It is difficult to name an invention that would have such a significant impact on the development of our civilization as the sword can boast. It cannot be considered as a banal murder weapon; the sword has always been something more. In different historical periods, this weapon was a symbol of status, belonging to a military caste or noble class. The evolution of the sword as a weapon is inextricably linked with the development of metallurgy, materials science, chemistry and mining.

In almost all historical periods, the sword was the weapon of the elite. And the point here is not so much the status of this weapon, but its high cost and the difficulty of producing high-quality blades. Making a sword that you could trust with your life in battle was not just a labor-intensive process, but a real art. And the blacksmiths who did this work can easily be compared to virtuoso musicians. It is not without reason that since ancient times, different nations have had legends about outstanding swords with special properties, made by real blacksmith masters.

The price of even an average blade could reach the cost of a small peasant farm. Products from famous masters were even more expensive. It is for this reason that the most common type of bladed weapon of Antiquity and the Middle Ages is a spear, but not a sword.

Over the centuries, developed metallurgical centers were formed in different regions of the world, the products of which were known far beyond their borders. They existed in Europe, the Middle East, India, China and Japan. The work of a blacksmith was revered and paid very well.

In Japan, the kaji (this is a blacksmith-armourer, “master of swords”) was on the same level as the samurai in the social hierarchy. Unheard of in this country. Craftsmen, which, in theory, blacksmiths should include, were even lower than peasants in the Japanese table of ranks. Moreover, samurai sometimes themselves did not hesitate to take up a blacksmith’s hammer. To show how respected Japan was for the work of a gunsmith, one fact can be cited. Emperor Gotoba (reigned in the 12th century) declared that making a Japanese sword was a job that even princes could do without diminishing their dignity in any way. Gotoba himself was not averse to working around the forge; several blades that he made with his own hands have been preserved.

Today, the media writes a lot about the skill of Japanese blacksmiths and the quality of the steel that was used to create the traditional katana. Yes, indeed, making a samurai sword required enormous skill and deep knowledge, but we can responsibly say that European blacksmiths were practically in no way inferior to their Japanese colleagues. Although there are legends about the hardness and strength of the katana, the making of a Japanese sword is not fundamentally different from the forging process of European blades.

Man began to use metals to make bladed weapons back in the 5th millennium BC. At first it was copper, which was quickly replaced by bronze - a durable alloy of copper with tin or arsenic.

By the way, the last component of bronze is very poisonous and often turned ancient blacksmiths and metallurgists into cripples, which is reflected in legends. For example, Hephaestus, the Greek god of fire and patron of blacksmithing, was lame; in Slavic myths, blacksmiths are also often depicted as crippled.

The Iron Age began at the end of the 2nd - beginning of the 1st millennium BC. Although, bronze weapons were used for many hundreds of years. In the 12th century BC. e. wrought iron was already used to make weapons and tools in the Caucasus, India and Anatolia. Around the 8th century BC. e. wrought iron appeared in Europe, and the new technology quickly spread across the continent. The fact is that the number of deposits of copper and tin in Europe is relatively small, but the reserves of iron are significant. In Japan, the Iron Age began only in the 7th century AD.

Making a sword. From ore to critsa

For a very long time, the technologies for producing and processing iron remained practically in one place; they could not properly satisfy the ever-growing demand for this metal, so there were few iron products and they were expensive. And the quality of tools and weapons made from this metal was extremely low. Surprisingly, for almost three thousand years metallurgy has not undergone any fundamental changes.

Before moving on to a description of the process of making edged weapons in ancient times, several definitions related to metallurgy should be given.

Steel is an alloy of iron with other chemical elements, primarily carbon. It determines the basic properties of steel: a large amount of carbon in steel ensures its high hardness and strength, while reducing the ductility of the metal.

The main method of producing iron in Antiquity and the Middle Ages (until the 13th century) was the cheese-blowing process, so named because unheated (“raw”) air was blown into the furnace. The main method of processing the resulting iron and steel was forging. The cheese-blowing process was very inefficient; most of the iron from the ore was lost along with the slag. In addition, the resulting raw materials were not of high quality and were very heterogeneous.

The production of iron from ore took place in a cheese furnace (a cheese furnace or domnitsa), which had a shape resembling a truncated cone, 1 to 2 meters high and a base diameter of 60-80 cm. Such a furnace was made of refractory brick or stone, coated with clay on top, which was then burned. A pipe led into the furnace to supply air; it was pumped in using bellows, and in the lower part of the house there was a hole for removing slag. A large amount of ore, coal and fluxes were loaded into the furnace.

Later, water mills were used to supply air to the furnace. In the 13th century, more advanced stoves appeared - stukofen, and then blauofen (15th century). Their productivity was much higher. A real breakthrough in metallurgy took place only at the beginning of the 16th century, when the conversion process was discovered, during which high-quality steel was obtained from ore.

The fuel for the cheese-making process was charcoal. Coal was not used due to the large amount of impurities it contains that are harmful to iron. They learned to coke coal only in the 18th century.

In a cheese furnace, several processes occur at once: waste rock is separated from the ore and leaves in the form of slag, and iron oxides are reduced, reacting with carbon monoxide and carbon. It fuses and forms the so-called kritsa. It contains cast iron. After receiving the kritsa, it is broken into small pieces and sorted by hardness, and then each fraction is worked on separately.

Today cast iron is the most important product of ferrous metallurgy; in the past it was different. It cannot be forged, therefore in ancient times cast iron was considered a useless waste product (“pig iron”), unsuitable for further use. It significantly reduced the amount of raw materials obtained during smelting. They tried to use cast iron: in Europe they made cannonballs from it, and in India, coffins, but the quality of these products left much to be desired.

From iron to steel. Forging a sword

The iron produced in the cheese furnace was extremely heterogeneous and of low quality. It took a lot more effort to turn it into a durable and deadly blade. Forging a sword involved several processes at once:

• iron and steel cleaning;
• welding different layers of steel;
• blade making;
• heat treatment of the product.

After this, the blacksmith needed to make the crosspiece, head, hilt of the sword, and also make a sheath for it.

Naturally, the cheese-blowing process is currently not used in industry to produce iron and steel. However, thanks to the efforts of enthusiasts and lovers of ancient edged weapons, it was recreated to the smallest detail. Today, this sword technology is used to create "authentic" historical weapons.

The kritsa obtained in the furnace consists of low-carbon iron (0-0.3% carbon content), metal with a carbon content of 0.3-0.6% and a high-carbon fraction (from 0.6 to 1.6% and above). Iron, which contains little carbon, is highly ductile, but it is very soft; the higher the carbon content in the metal, the greater its strength and hardness, but at the same time the steel becomes more brittle.

To impart the desired properties to the metal, the blacksmith can either saturate the steel with carbon or burn off its excess. The process of saturating a metal with carbon is called carburization.

The blacksmiths of the past faced a serious problem. If you make a sword from high-carbon steel, it will be durable and hold an edge well, but at the same time it will be too fragile; a weapon made from low-carbon steel will not be able to perform its functions at all. The blade must be both hard and elastic at the same time. This was the key problem that faced gunsmiths for many hundreds of years.

There is a description of the use of long swords by the Celts by the Roman historian Polybios. According to him, the swords of the barbarians were made of such soft iron that they became blunt and bent after every decisive blow. From time to time, Celtic warriors had to straighten their blades using their feet or knees. However, the very fragile sword posed a huge danger to its owner. For example, a broken sword almost cost the life of Richard the Lionheart, the English king and one of the most famous fighters of his time.

In that era, a broken sword meant about the same thing as failed car brakes today.

The first attempt to solve this problem was the creation of so-called laminated swords, in which soft and hard layers of steel alternated with each other. The blade of such a sword was a multi-layer sandwich, which allowed it to be both strong and elastic at the same time (in this case, however, the correct heat treatment of the weapon and its hardening played an important role). However, there was one problem with such swords: when sharpening, the surface hard layer of the blade quickly ground off and the sword lost its properties. Laminated blades already appeared among the Celts; according to modern experts, such a sword should have cost ten times more than a regular one.

Another way to make a strong and flexible blade was surface cementation. The essence of this process was to carburize the surface of a weapon made of a relatively soft metal. The sword was placed in a vessel filled with organic matter (most often coal), which was then placed in a furnace. Without access to oxygen, the organic matter charred and saturated the metal with carbon, making it stronger. The problem with cemented blades was the same as with laminated ones: the surface (hard) layer wore off quite quickly, and the blade lost its cutting properties.

More advanced were multilayer swords made according to the “steel-iron-steel” pattern. It made it possible to create blades of excellent quality: the soft iron “core” made the blade flexible and elastic, well absorbed vibrations during impacts, and the hard “shell” endowed the sword with excellent cutting properties. It should be noted that the above blade layout diagram is the simplest. In the Middle Ages, gunsmiths often "built" their products from five or seven "packs" of metal with different characteristics.

Already in the early Middle Ages, large metallurgical centers were formed in Europe, in which a significant amount of steel was smelted and weapons of fairly high quality were produced. Typically, such centers arose near rich deposits of iron ore. In the 9th-10th centuries, good blades were made in the state of the Franks. Charlemagne even had to issue a decree according to which it was strictly forbidden to sell weapons to the Vikings. The recognized center of European metallurgy was the area where the famous Solingen later arose. Iron ore of excellent quality was mined there. Later, Italian Brescia and Spanish Toledo became recognized centers of blacksmithing.

It is curious, but already in the early Middle Ages, blades of famous gunsmiths were often counterfeited. For example, the swords of the famous master Ulfbrecht (lived in the 9th century) were distinguished by excellent balance and were made of perfectly processed steel. They were marked with the personal sign of the gunsmith. However, the blacksmith simply physically could not make all the blades that are attributed to him. And the blades themselves vary greatly in quality. During the late Middle Ages, Solingen craftsmen counterfeited the products of blacksmiths from Passau and Toledo. There are even written complaints from the latter about such “piracy.” Later they began to counterfeit the swords of Solingen itself.

The selected strips are heated and then welded into a single block using forging. During this process, it is important to maintain the correct temperature and not burn the workpiece.

After welding, the forging of the blade begins, during which its shape is formed, the fullers are made, and the shank is made. One of the main stages of forging is the process of compacting the blades, which concentrates the layers of steel and allows the sword to retain its cutting properties longer. At this stage, the geometry of the blade is finally formed, the location of its center of gravity is determined, and the thickness of the metal at the base of the sword and at its tip is set.

Medieval blacksmiths, of course, did not have thermometers. Therefore, the required temperature was calculated based on the glow color of the metal. To better define this characteristic, in the past, forges were usually darkened, which further added mysticism to the aura of blacksmiths.

Then the heat treatment of the future sword begins. This stage is extremely important; it allows you to change the molecular structure of the steel and achieve the necessary characteristics from the blade. The fact is that forged steel, welded from various pieces, has a coarse grain structure and a large number of stresses within the metal. With the help of normalization, hardening and tempering, the blacksmith must get rid of these shortcomings as much as possible.

Initially, the blade is heated to about 800 degrees, and then suspended by the shank so that the metal does not “lead.” This process is called normalization; for different types of steel this procedure is carried out several times. Normalization is followed by a gentle annealing, during which the sword is heated to a brownish-red color and left to cool, wrapped in insulating material.

After normalization and annealing, you can begin the most important part of the forging process - hardening. During this procedure, the blade is heated to a brownish-red color and then quickly cooled in water or oil. Hardening freezes the steel structure obtained during normalization and annealing.

Differentiated hardening. This technique is typical for Japanese masters; it consists in the fact that different zones of the blade receive different hardening. To achieve this effect, layers of clay of varying thickness were applied to the blade before hardening.

It is absolutely clear that at any stage of the process described above, the blacksmith can make a mistake that will be fatal to the quality of the future product. In Japan, any blacksmith who valued his name had to ruthlessly break failed blades.

To improve the quality of the future sword, the method of nitration or nitriding was often used, that is, the treatment of steel with compounds containing nitrogen.

The saga of Wiland the Blacksmith describes a rather original method of nitration, which allowed the master to create a real “super sword”. To improve the quality of the product, the blacksmith sawed the sword into sawdust, added it to the dough and fed it to hungry geese. After that, he collected bird droppings and forged sawdust. They made a sword “... so hard and strong that it was difficult to find a second one on earth.” Of course, this is a literary work, but a similar method could well have taken place. Modern “nitrogen” steels have the highest hardness. Many historical sources report that swords were tempered in blood, which endowed them with special qualities. It is likely that such a practice actually took place, and here we are dealing with another method of nitration.

Immediately after hardening, the blade is released again. After the end of the heat treatment process, grinding begins, and it is carried out in several stages. During this process, the sword must be constantly cooled with water. In the Middle Ages, the grinding and polishing of a sword, as well as the installation of a crosspiece, hilt and pommel, was usually done not by a blacksmith, but by a special master - a schwertfeger.

Naturally, before starting work on the sword, the blacksmith thought through its future design and construction to the smallest detail. Will it be combat or is it intended more for “representational” purposes? How will its future owner mainly fight: on foot or on horseback? What armor is it expected to be used against? And, of course, during the manufacture of the sword, the characteristics of the warrior himself were taken into account: his height, the length of his arms, his favorite fencing technique.

Damascus steel and damask steel

Anyone who has been interested in historical edged weapons at least once in their life knows the phrase “Damascus steel.” Even today it fascinates with its touch of mystery, exoticism and masculinity. In fact, Damascus steel is another attempt to solve the eternal contradiction between the brittleness of steel and the softness of iron. And I must say that this attempt turned out to be one of the most successful.

It is unknown who first came up with the idea of ​​combining together a large number of layers of soft and hard steel, but this person can safely be called a genius of blacksmithing. Although, today historians believe that such technology was independently developed in different regions of the world. Already at the beginning of our era, weapons from Damascus steel were made in Europe and China. Previously it was believed that this type of steel was invented in the Middle East. However, today it is known for certain that it was invented by European masters. And in general, no evidence has yet been found that Damascus was ever a serious center for the production of weapons.

Wild Damascus was obtained if the original piece was cut in half, the halves were placed on top of each other and forged again. A similar operation was usually carried out several times, constantly doubling the number of layers of metal, thereby improving its properties. A simple mathematical calculation shows that a billet, forged seven times, receives 896 layers of high-carbon and low-carbon steel.

In the Middle Ages, the so-called twisted damask was popular in Europe. During its production, bars from different steels were twisted into a spiral and welded by forging. This process was repeated several times. Typically, the central part of the blade was made from such steel, onto which blades of ordinary hard steel were then forged.

Damascus steel blades were so highly valued in medieval Europe that they were often given to kings.

Bulat or wutz is steel made in a special way, thanks to which it has a unique internal structure, a characteristic pattern on the surface and the highest characteristics of strength and elasticity. It was made in Iran, Central Asia and India. This steel had a high carbon content, close to cast iron (about 2%), but at the same time retained the ability to forge and significantly exceeded cast iron in strength.

There are many legends about this material. For a long time it was believed that the secret of making damask steel was lost, although today many craftsmen claim that they know the secrets of making real wutz. One of the methods for its production is based on the partial melting of particles of iron or low-carbon steel in cast iron. The total amount of additives should be 50-70% by weight of cast iron. The result is a melt that has a mushy consistency. After cooling and crystallization, damask steel is obtained - a material with a high-carbon matrix interspersed with low-carbon particles.

There is information about other methods of producing damask steel in our days; probably, there were several of them in ancient times. Modern methods are associated with special methods of forging and heat treatment of metals.

One of the advantages of any sword made of patterned steel, be it Damascus or damask steel, is what experts call the micro-waviness of its blade. It automatically arises due to the heterogeneity of the layers or fibers of the metal that make up the blade. In fact, the cutting edge of such a weapon is a “micro saw,” which significantly increases its combat properties.

There are a huge number of myths about Damascus steel. The first of them is related to the name of the metal itself. Today it is known that the city of Damascus had no special connection with the invention and production of this steel, although some historians consider it an important trading center where Damascus weapons were sold. There is also still an opinion that Damascus steel was “worth its weight in gold” and cut armor like paper. This is not true. Damascus blades really perfectly combine hardness and elasticity, but they do not possess any extraordinary properties.

If you have any questions, leave them in the comments below the article. We or our visitors will be happy to answer them

Ton-ton.

Tonn-tenn-kann! Tonn-tenn-kann!

Ton-ton.

The sound from my telekinetic strikes mixed with something else.

Ton-ton-ton.

Oh, it looks like someone has come and is knocking on the door.

"-Fran."

It's good that Fran has already opened her eyes. Because waking her up is not an easy task. And if they saw that Fran was sleeping, how would we explain the sounds I made? We could hardly say that she forges while she sleeps.

“Princess-sama, good morning!”

Section No. of the village stood in front of the doors in a deep bow. In his hands he held a basket with bread and something else. Looks like he brought it on purpose.

- Here's breakfast.

- Thank you.

- No, no, what are you talking about? We worked all night, is everything okay?

Oh, were the sounds really loud?

— Did you make noise? Sorry.

- What are you saying, on the contrary! It’s for our sake that you even do this, all the residents are very grateful!

Fran then discussed today's plans with the head. We will continue to forge. Villagers - train in magic and fencing. Some of the old people will be cleaning the armor.

“It’s not necessary for everyone to train in magic and with a sword.

- Yes, I told them that it was of my own free will. But it seems like everyone wants to learn.

Still, the fact that one of them could possibly use magic was a great motivation.

Perhaps even black cats capable of magic will appear faster than I thought.

- Well, if you need anything, please call me.

While Section No. left the bread, we returned to the usual method of blacksmithing. I hit the ingots made in the forge, and Fran restored the armor and shields.

“The fact that you can improve your own knowledge with skills is the best thing in this world.”

Even I, who have never had experience in blacksmithing, know how to forge a sword. But in this world there is a special way of casting. The metal had to be poured into the mold, and depending on the situation, sometimes it was only necessary to hammer it at the end.

I don’t remember too well, but Japanese forging was very different from European. But here both the manufacturing method and the materials are different from those, so it’s probably wrong to compare them? Although I'm not good at forging, so I can't say for sure.

But in this world there is magic and magical tools, so you can make a sword with less effort, and at the same time make it more durable.

With magic you can make metal stronger, and by beating it with a hammer you can use magical flame, so you don’t even have to be in a forge.

Well, of course, this only applies to mediocre weapons; if you do something more worthy, then a forge is needed from start to finish.

“First, let’s collect a few ingots.”

Using Parallel Thinking and Telekinesis while simultaneously casting, hammering and polishing, I mass produced simple swords. But even with such a system, good swords were obtained only thanks to the tenth level of the Blacksmithing skill.

“Great, 50 pieces, is that probably enough?”

Together with those that were not damaged, it turns out to be about 80 pieces. For just starting black cats, these will be just right.

“Maybe I’ll try something.”

I'll experiment with the remaining ingots. Of course, if we come up with something worthy, we’ll give the village black cats.

“First, I’ll try to forge a sword.”

Thanks to the Blacksmithing skill, forging was possible with an understanding of what to do. So I heated the ingot until it was completely red, and then I hammered it into shape. So, heating and forging, I made one sword. It's strange, but I even knew when to stop. Apparently, thanks to the Production skill.

The quality of this sword was not bad, but it was also somehow special. Something like this. In general, the material was not particularly good, so maybe this is logical. Previous swords were called “Iron Sword”, and this one is called “Base Metal Sword”.

With such materials and level of skill, this is probably the limit. But I wanted to somehow improve it.

At the very least, put magic into forging. There are materials into which you cannot put a lot of magic, but I would like to invest at least as much as they allow. And to get materials, you can look for the necessary Demonic Beasts, and turning their bones into ash, mix it with metals. Even if they are weak animals, they are still magical. Their bones contain a small amount of magical energy, so this can increase the amount of magic in the sword.

Well, it's just an idea, so I don't know if it will actually work.

" - ABOUT? And that’s nothing.”

It took longer, but it turned out something interesting. Probably the metal changed its structure, but I was surprised that the hammer deteriorated.

And what I got was a Sword made from low-grade magical metal. I was unable to do anything with the quality of the metal, but I managed to create a magical thing. And indeed, there was a little magic in it. The conductivity of magic also changed from F to F+. Now it will be possible to attack enemies without a physical body. I really don’t know how many times I’ll have to hit it.

Name: Iron Sword

Attack: 88 Magic: 0 Durability: 300

Magic Conductivity: F-

Skills: no

Name: Sword made of base metal

Attack: 114 Magic: 1 Durability: 380

Magic Conductivity: F

Skills: no

Name: Sword made of low grade magical metal

Attack: 124 Magic: 10 Durability: 390

Magic Conductivity: F+

Skills: no

Something like this. Well, I’ll make magic swords from the remaining ingots. By the way, the sword forged by old man Gallas was like this:

Name: High grade steel long sword

Attack: 398 Magic: 5 Durability: 600

Magic Conductivity: F

Skills: no

I realized that I had underestimated the toughness of old Gallas. While I was thinking about this, Fran quietly approached.

- Mentor.

“Fran? What's happened."

- I'm hungry.

- Aww......

“Oh, it’s already such a time.”

I completely lost track of time. Our usual lunch time is long past.

“Sorry, I’ll cook it now.”

They don't cook lunch for us. In this village everyone eats only twice a day. But princesses eat three times a day. Well, I also understand that the village is poor.

When we resolve the matter with old man Gallas, we will come here again. Let's take a bunch of grain and seedlings with us.

“Come on, I’ll make some curry as an apology.”

- Is it true?

“Today you can eat as much as you want.”

- Ooh! Paradise!

“Grandiose, isn’t it?”

- Curry heaven! This is the name of the heavenly country.

Fran started composing ballads out of happiness. Well, if it would make her feel better, I got off easy. But there are fewer and fewer caries. After all, they eat it in huge portions at every opportunity. I don't know what will happen to Fran's mood if the curry runs out.

- Umm-umm!

For Fran, there is nothing worse than not eating her favorite food. Fortunately, no one is watching here and there are enough ingredients. Well, then I will cook the karia for the remaining time.

The Japanese sword leaves few weapon connoisseurs indifferent. Some believe that this is the best sword in history, the unattainable pinnacle of perfection. Others say that this is a mediocre craft that cannot stand comparison with swords of other cultures.

There are also more extreme opinions. Fans may argue that the katana cuts steel, that it cannot be broken, that it is lighter than any European sword of similar dimensions, and so on. Detractors say that the katana is at the same time fragile, soft, short and heavy, that it is an archaic and dead-end branch of the development of edged weapons.
The entertainment industry is on the fans' side. In anime, movies and computer games, Japanese-type swords are often endowed with special properties. The katana can be the best weapon of its class, or it can be the mega sword of the protagonist and/or the villain. Suffice it to recall a couple of Tarantino films. You can also remember the action films about ninjas from the 80s. There are too many examples to seriously mention.
The problem is that, due to the massive pressure of the entertainment industry, some people's filter, designed to separate the real from the fictional, fails. They begin to believe that the katana is truly the best sword, “after all, everyone knows it.” And then a natural desire for the human psyche arises to reinforce one’s point of view. And when such a person encounters criticism from the object of his adoration, he takes it with hostility.
On the other hand, there are people who have knowledge about certain shortcomings of the Japanese sword. Such people often react to fans who uncontrollably praise the katana with initially quite healthy criticism. Most often, in response - remember about the hostile reception - these critics receive an inadequate tub of slop, which often infuriates them. The argumentation on this side also goes towards the absurd: the advantages of the Japanese sword are hushed up, the shortcomings are exaggerated. Critics turn into scolders.
So there is an ongoing war, fueled on the one hand by ignorance, and on the other by intolerance. As a result, most of the available information about the Japanese sword comes from either fans or detractors. Neither one nor the other can be taken seriously.
Where is the truth? What exactly is a Japanese sword, what are its strengths and weaknesses? Let's try to figure it out.

Iron ore mining

It is no secret that swords are made of steel. Steel is an alloy of iron and carbon. Iron comes from ore, carbon comes from wood. In addition to carbon, steel may contain other elements, some of which have a positive effect on the quality of the material, while others have a negative effect.
There are many varieties of iron ore, such as magnetite, hematite, limonite and siderite. They differ, essentially, in impurities. In any case, the ores contain iron oxides, and not pure iron, so iron always has to be reduced from the oxides. Pure iron, not in the form of oxides and without significant amounts of impurities, is extremely rare in nature, not on an industrial scale. These are mainly fragments of meteorites.
In medieval Japan, iron ore was obtained from so-called iron sand or satetsu (砂鉄), containing grains of magnetite (Fe3O4). Iron sand is still an important source of ore today. Magnetite from sand is mined, for example, in Australia, including for export to Japan, where iron ore has long since run out.
You need to understand that other types of ore are no better than iron sand. For example, in medieval Europe, an important source of iron was bog ore, bog iron, containing goethite (FeO(OH)). There are also many non-metallic impurities there, and they need to be separated in the same way. Therefore, in a historical context, it is not very important what kind of ore was used to make steel. What is more important is how it was processed before and after smelting.
The controversy over the quality of the Japanese sword begins with a discussion of ore. Fans claim that satetsu ore is very pure and makes very advanced steel. Detractors say that when ore is mined from sand, it is impossible to get rid of impurities, and the resulting steel is of low quality, with a large number of inclusions. Who is right?
It’s paradoxical, but both are right! But not at the same time.
Modern methods of purifying magnetite from impurities actually make it possible to obtain very pure iron oxide powder. Therefore, the same swamp ore is commercially less interesting than magnetite sand. The problem is that these cleaning methods use powerful electromagnets that are relatively new.
The medieval Japanese had to either make do with clever methods of cleaning the sand using coastal waves, or separate grains of magnetite from the sand by hand. In any case, if you mine and refine magnetite using truly traditional methods, you will not get pure ore. There will remain quite a lot of sand, that is, silicon dioxide (SiO2), and other impurities.
The statement “Japan had bad ore, and therefore the steel for Japanese swords is by definition of low quality” is incorrect. Yes, Japan actually had less iron ore than Europe. But qualitatively it was no better and no worse than the European one. In both Japan and Europe, in order to obtain high-quality steel, metallurgists had to get rid of impurities that inevitably remained after smelting in a special way. For this, very similar processes were used, based on forging welding (but more on that later).
Therefore, statements such as “satetsu is a very pure ore” are true only in relation to magnetite, separated from impurities by modern methods. In historical times it was a dirty ore. When modern Japanese make their swords in the “traditional way,” they are lying because the ore for these swords is refined with magnets, not by hand. So these are no longer traditional steel swords, since the raw materials used for them are of a higher quality. Gunsmiths, of course, can be understood: there is no practical sense in using obviously inferior raw materials.

Ore: conclusion

Steel for nihonto, produced before the industrial revolution came to Japan, was made from ore that was dirty by modern standards. The steel for all modern nihonto, even those forged in the most remote and authentic Japanese villages, is made from pure ore.

If sufficiently advanced steel smelting technologies are available, the quality of the ore is not particularly important, since impurities will be easily separated from the iron. However, historically in Japan, as in medieval Europe, there were no such technologies. The fact is that the temperature at which pure iron melts is approximately 1539° C. In reality, you need to reach even higher temperatures, with a margin. It’s impossible to do this “on your knees”; you need a blast furnace.

Without relatively new technologies, achieving temperatures sufficient to melt iron is very difficult. Only a few cultures were able to do this. For example, high-quality steel ingots were produced in India, and merchants were already transporting them all the way to Scandinavia. In Europe, they learned to normally reach the required temperatures somewhere around the 15th century. In China, the first blast furnaces were built as early as the 5th century BC, but the technology did not spread outside the country.

The traditional Japanese cheese oven, tatara (鑪), was a fairly advanced device for its time. She coped with the task of obtaining the so-called tamahagane (玉鋼), “diamond steel.” However, the temperature that could be reached in Tatar did not exceed 1500 ° C. This is more than enough to reduce iron from its oxides, but not enough for complete melting.

Complete melting is necessary primarily to separate out the undesirable impurities inevitably contained in traditionally mined ore. For example, sand releases oxygen when heated and turns into silicon. This silicon turns out to be imprisoned somewhere inside the iron. If iron becomes completely liquid, then unwanted impurities like silicon simply float to the surface. From there they can be scooped out with a spoon or left so that they can later be removed from the cooled pig.

Iron smelting in the Tatar, as in most similar ancient furnaces, was not complete. Therefore, the impurities did not float to the surface in the form of slag, but remained in the thickness of the metal.

It should be mentioned that not all impurities are equally harmful. For example, nickel or chromium make stainless steel, while vanadium is used in modern tool steel. These are so-called alloying additives, the benefit of which will be at a very low content, usually measured in fractions of a percent.

In addition, carbon should not be considered an impurity at all when it comes to steel, because steel is an alloy of iron and carbon in a certain proportion, as noted earlier. However, when melting in Tatar we are dealing not only and not so much with alloying additives of the type mentioned above. Slag remains in the steel, mainly in the form of silicon, magnesium, and so on. These substances, as well as their oxides, are significantly worse in terms of hardness and strength characteristics than steel. Steel without slag will always be better than steel with slag.

Steelmaking: conclusion

Nihonto steel, smelted using traditional methods from traditionally mined ore, contains a significant amount of slag. This degrades its quality compared to steel produced using modern technologies. If you take modern, pure ore, the resulting “almost traditional” steel will turn out to be of noticeably higher quality than truly traditional steel.

The Japanese sword is made from a traditionally prepared steel called tamahagane. The blade contains carbon in different concentrations in different areas. The steel is folded in several layers and is zone hardened. These are widely known facts; you can read about them in almost any popular article about the katana. Let's try to find out what this means and what impact it has.

To get answers to these questions, you will need an excursion into metallurgy. We won't go into too much depth. Many nuances are not mentioned in this article; some points are deliberately simplified.

Material properties

Why are swords even made of steel and not, say, wood or cotton candy? Because steel as a material has more suitable properties for creating swords. Moreover, for creating swords, steel has the most suitable properties of all materials available to mankind.

Not much is required from a sword. It should be strong, sharp and not too heavy. But all three of these properties are absolutely necessary! A sword that is not strong enough will quickly break, leaving its owner without protection. A sword that is not sharp enough will be ineffective in causing damage to the enemy and will also not be able to protect its owner. A sword that is too heavy, at best, will quickly exhaust the owner, and at worst, it will be completely unsuitable for combat.

Now let's look at these properties in detail.

During operation, swords are subject to powerful physical impacts. What will happen to the blade if you hit it on a target, whatever it may be? The result depends on what the target is and how you hit it. But it also depends on the design of the blade with which we hit.

First of all, the sword must not break, that is, it must be durable. Strength is the ability of objects not to break from internal stresses arising under the influence of external forces. The strength of a sword is mainly influenced by two components: geometry and material.

With geometry, everything is generally clear: a crowbar is more difficult to break than a wire. However, the crowbar is much heavier, and this is not always desirable, so you have to resort to tricks that minimize the weight of the weapon while maintaining maximum strength. By the way, you can immediately notice that all types of steel have approximately the same density: approximately 7.86 g/cm3. Therefore, reducing mass is achievable only by geometry. We'll talk about it later, for now let's get on with the material.

In addition to strength, hardness is important for a sword, that is, the ability of the material not to deform under external influence. A sword that is not hard enough can be very strong, but it will not be able to stab or cut. An example of such a material is rubber. A sword made of rubber is almost impossible to break, although it can be cut - again the lack of hardness affects it. But more importantly, its blade is too soft. Even if you make a “sharp” rubber blade, it can only cut cotton candy, that is, an even less hard material. When trying to cut even wood, a blade made of a sharp but soft material will simply bend to the side.

But firmness is not always useful. Often, instead of hardness, plasticity is needed, that is, the ability of a body to deform without self-destruction. For clarity, let’s take two materials: one with a very low hardness - the same rubber, and the other with a very high hardness - glass. In rubber or leather boots, which dynamically bend with your foot, you can walk calmly, but in glass boots, you just can’t. A glass shard can cut rubber, but a rubber ball will easily break window glass without causing injury.

A material cannot simultaneously have high hardness and at the same time be plastic. The fact is that when deformed, a body made of solid material does not change shape, like rubber or plasticine. Instead, it first resists and then breaks, splitting - because it needs somewhere to put the strain energy that accumulates in it, and it is not able to extinguish this energy in a less extreme way.

At low hardness, the molecules that make up the material are not tightly bound. They move calmly relative to each other. Some soft materials return to their original shape after deformation, others do not. Elasticity is the property of returning to its original shape. For example, stretched rubber will come back together unless you overdo it, and plasticine will retain the shape that it is given. Accordingly, rubber deforms elastically, and plasticine deforms plastically. By the way, solid materials are more elastic than plastic: at first they do not deform, then they deform slightly elastically (if you let go here, they will return to shape), and then they break.

Types of steel

As mentioned above, steel is an alloy of iron and carbon. More precisely, it is an alloy containing from 0.1 to 2.14% carbon. Less is iron. More, up to 6.67% – cast iron. The more carbon, the higher the hardness and the lower the ductility of the alloy. And the lower the ductility, the higher the fragility.

In reality, of course, everything is not so simple. It is possible to obtain high-carbon steel that will be more ductile than low-carbon steel, and vice versa. There is much more to metallurgy than one iron-carbon diagram. But we have already agreed to simplify things.

Steel containing very little carbon is ferrite. What is “very little”? Depends on various factors, primarily temperature. At room temperature, this is somewhere up to half a percent, but you need to understand that you should not look for excessive clarity in an analog world full of smooth gradients. Ferrite is close in properties to pure iron: it has low hardness, is deformed plastically and is ferromagnetic, that is, it is attracted to magnets.

When heated, steel changes phase: ferrite turns into austenite. The easiest way to determine whether a heated steel workpiece has reached the austenite phase is to hold a magnet close to it. Unlike ferrite, austenite does not have ferromagnetic properties.

Austenite differs from ferrite in having a different crystal lattice structure: it is wider than that of ferrite. Everyone remembers about thermal expansion, right? This is where it shows up. Thanks to the wider lattice, austenite becomes transparent to individual carbon atoms, which can, to a certain extent, travel freely within the material, ending up right inside the cells.

Of course, if you heat the steel even higher, until it completely melts, then carbon will travel even more freely in the liquid. But now this is not so important, especially since with the traditional Japanese method of producing steel, complete melting does not occur.

As molten steel cools, it first becomes hard austenite and then changes back to ferrite. But this is a general case for “ordinary” carbon steels. If you add nickel or chromium to steel in an amount of 8-10%, then upon cooling the crystal lattice will remain austenitic. This is how stainless steels are made, in fact alloys of steel with other metals. As a rule, they are inferior to ordinary alloys of iron and carbon in terms of hardness and strength, so swords are made of “rusting” steel.

With modern metallurgical technologies, it is quite possible to obtain stainless steel comparable in hardness and strength to high-quality samples of historical carbon steel. Although modern carbon steel will still be better than modern stainless steel. But, in my opinion, the main reason for the lack of stainless steel swords is market inertia: gunsmiths’ clients do not want to purchase swords made of “weak” stainless steel, plus many value authenticity - despite the fact that this is essentially fiction, as discussed in the previous article .

Getting Tamahagane

We take iron ore (satetsu magnetite) and bake it. We would like to completely melt it, but it won’t work – the Tatara can’t handle it. But nothing. We heat it, bring it to the austenitic phase and continue heating until it stops. We add carbon by simply pouring coal into the stove. Add satetsu again and continue baking. It is still possible to melt some of the steel, but not all. Then let the material cool.

As the steel cools, it tries to change phase, turning from austenite to ferrite. But we added a significant amount of unevenly distributed coal! Carbon atoms, which moved freely inside liquid iron and normally existed inside a wide austenite lattice, when compressed and changed phase, begin to be squeezed out of a narrower ferrite lattice. It’s okay from the surface, there is somewhere to squeeze out, just into the air - and that’s good. But in the thickness of the material there is nowhere to go.

As a result of the transition of iron from austenite, part of the cooled steel will no longer be ferrite, but cementite, or iron carbide Fe3C. Compared to ferrite, it is a very hard and brittle material. Pure cementite contains 6.67% carbon. We can say that this is “maximum cast iron”. If there is more carbon in any part of the alloy than 6.67%, then it will not be able to disperse into iron carbide. In this case, the carbon will remain in the form of graphite inclusions without reacting with the iron.

When the tatara cools, a steel block weighing about two tons forms at its bottom. The steel in this block is not uniform. In those areas where satetsu borders on coal, there will not even be steel, but cast iron containing a large amount of cementite. In the depths of the satetsu, far from the coal, there will be ferrite. In the transition from ferrite to cast iron - various structures of iron-carbon alloys, which for simplicity can be defined as pearlite.

Perlite is a mixture of ferrite and cementite. During cooling and the phase transition from austenite to ferrite, as already mentioned, carbon is squeezed out of the crystal lattice. But in the thickness of the material there is nowhere to squeeze it out, only from one place to another. Due to various inhomogeneities during cooling, it turns out that part of the lattice squeezes out this carbon, turning into ferrite, and the other part accepts, turning into cementite.

When cut, perlite looks like zebra skin: a sequence of light and dark stripes. Most often, cementite is perceived as whiter than dark gray ferrite, although this all depends on lighting and viewing conditions. If there is enough carbon in pearlite, then the striped areas will be combined with purely ferritic ones. But this is all perlite too, just low-carbon.

The furnace walls are destroyed and the steel block is broken into pieces. These pieces are gradually crushed into very small pieces, meticulously inspected, and, if possible, cleaned of slag and excess carbon-graphite. Then they are heated to a soft state and flattened, resulting in flat ingots of arbitrary shape, reminiscent of coins. During the process, the material is sorted by quality and carbon content. The highest quality pieces of coins go to the production of swords, the rest go anywhere. With carbon content, everything is quite simple.

Ferrite obtained from tamahagane is called hocho-tetsu (包丁鉄) in Japanese. The correct English notation is “houchou-tetsu” or “hōchō-tetsu”, possibly without the hyphen. If you search as “hocho-tetsu” you won’t find anything good.

Perlite is precisely tamahagane. More precisely, the word “tamahagane” refers to both the resulting steel as a whole and its pearlite component.

Hard cast iron made from tamahagane is called nabe-gane (鍋がね). Although there are several names for cast iron and its derivatives in Japanese: nabe-gane, sentetsu (銑鉄), chutetsu (鋳鉄). If you are interested, then you can figure out for yourself when which of these words is correct to use. Not the most important thing in our business, to be honest.

The traditional Japanese method of steel smelting is not something highly sophisticated. It does not completely eliminate the toxins that are inevitably present in traditionally mined ore. However, it copes well with the main task - producing steel. The output is small pieces of iron-carbon alloys, similar to coins, with varying carbon content. Various types of alloys are involved in the further production of the sword, from soft and ductile ferrite to hard and brittle cast iron.

Composite steel

Almost all technological processes for producing steel for the production of swords, including Japanese, produce steel of different grades, with different carbon contents, and so on. Some varieties are more hard and brittle, others are soft and flexible. Gunsmiths wanted to combine the hardness of high-carbon steel with the strength of low-carbon steel. Thus, independently of each other, in different parts of the world, the idea of ​​​​producing swords from composite steel appeared.

Among fanatics of Japanese swords, the fact that the objects of their veneration were traditionally made in this way, from “many layers of steel”, is extolled as some kind of achievement that distinguishes the Japanese sword from other, “primitive” types of weapons. Let's try to figure out why this view of things is wrong.

Elements of technology

The general principle: pieces of steel of the desired shape are taken, assembled in one way or another and welded by forging. To do this, they are heated to a soft, but not liquid state, and driven into each other with a sledgehammer.

Assembly (piling)

The actual formation of a workpiece from pieces of material, most often with different characteristics. The pieces are welded by forging.

Typically, rods or strips are used the entire length of the product so as not to create weak points along the length. But you can assemble it in different ways.

Random structural assembly is the most primitive method in which pieces of metal of arbitrary shape are assembled at random. A random structural assembly is usually also a random compositional one.

Random compositional assembly - with such swords it is not possible to identify a meaningful strategy for distributing strips of material with different carbon and/or phosphorus content.

Phosphorus has not been mentioned previously. This additive is both beneficial and harmful, depending on the concentration and type of steel. For the purposes of this article, the properties of phosphorus in alloys with steel are not particularly important. But in the context of assembly, it is important that the presence of phosphorus changes the visible color of the material, or more precisely, its reflective properties. More on this later.

Structural assembly is the opposite of random structural assembly. The strips from which the workpiece is assembled have clear geometric outlines. There is a certain intention in the formation of the structure. However, such blades can still be randomly composed.

Composite assembly is an attempt to intelligently arrange different grades of steel in different areas of the blade - for example, creating a hard blade and a soft core. Composite assemblies are always structural.

It is worth mentioning exactly what structures were usually formed.

The simplest option is to stack three or more strips, with the top and bottom strips forming the surface of the blade, and the middle strip forming its core. But there was also its complete opposite, when the workpiece was assembled from five or more rods lying nearby. The outer rods form the blades, and everything between them forms the core. Intermediate, more complex options were also encountered.

For Japanese swords, assembly is a very common technique. Although not all Japanese swords were assembled in the same way, and not all of them were assembled at all. In modern times, the most common option is the following: the blade is hard steel, the core and back are soft steel, the side planes are medium steel. This variant is called sanmai or honsanmai, and it can be considered a kind of standard. When we talk about the structure of a Japanese sword in the future, we will have in mind just such an assembly.

But, unlike modern times, most historical swords have a kobuse structure: a soft core and back, a hard blade and side planes. They are indeed followed by sanmai swords, then by a large margin - maru, that is, swords not made of composite steel, just hard. Other tricky options, such as Orikaeshi Sanmai or Soshu Kitae, attributed to the legendary blacksmith Masamuna, exist in homeopathic doses and are mostly simply the products of experimentation.

Folding

It involves folding a fairly thinly flattened piece in half, heated to a soft state.

This element of technology, together with its manifestation from the next paragraph, is probably promoted more than others as the basis for the perfection of Japanese swords. Everyone has probably heard about the hundreds of layers of steel that Japanese swords are made of? So here it is. Take one layer and fold it in half. It's already two. Double again - four. And so on, in powers of two. 27=128 layers. Nothing special.

Fagging

Homogenization of material through repeated folding.

Bunching is necessary when the material is far from perfect - that is, when working with traditionally obtained steel. In fact, by “special Japanese folding” they mean stacking, because it is to remove impurities and homogenize slag that Japanese sword blanks are folded about 10 times. When folded ten times, the result is 1024 layers, so thin that they are no longer there - the metal becomes homogeneous.

Bagging allows you to get rid of impurities. With each thinning of the workpiece, more of its contents become part of the surface. The temperature at which all this happens is very high. As a result, some of the slag burns out, contacting oxygen in the air. Unburned pieces from repeated processing with a sledgehammer are sprayed in a relatively even concentration throughout the entire workpiece. And this is better than having one specific large weakness somewhere in a certain place.

However, bundling also has its downsides.

Firstly, the slag, consisting of oxides, does not burn out - it has already burned out. This slag partially remains inside the workpiece, and it is impossible to get rid of it.

Secondly, carbon burns out along with unwanted impurities when folding steel. This can and should be taken into account when using cast iron as a raw material for future hard steel, and hard steel for future soft steel. However, it’s already clear here that you can’t endlessly batch - you’ll end up with iron.

Thirdly, in addition to the slag, at the temperatures at which folding and packaging takes place, the iron itself burns, that is, oxidizes. It is necessary to remove iron oxide flakes that appear on the surface before folding the workpiece, otherwise a defect will result.

Fourthly, with each subsequent folding, the iron becomes less and less. Some of it burns, going into oxide, and some of it just falls off the edges or needs to be cut off. Therefore, it is necessary to immediately calculate how much more material will be needed. But it's not free.

Fifthly, the surface on which packaging is performed cannot be sterile, and neither can the air in the forge. With each folding, new impurities enter the workpiece. That is, up to a certain point, packaging reduces the percentage of contamination, but then begins to increase it.

Taking into account the above, it can be understood that folding and packaging is not some kind of super technology that allows you to obtain some unprecedented properties from metal. This is just a way to, to a certain extent, get rid of the defects of the material inherent in traditional methods of producing it.

Why aren't swords cast?

In many fantasy films, a beautiful montage shows the process of making a sword, usually for the main character or, conversely, for some evil antagonists. A common image from this montage: molten orange metal being poured into an open mold. Let's look at why this doesn't happen.

Firstly, molten steel has a temperature of about 1600° C. This means that it will not glow a soft orange, but a very bright yellowish-white color. In the movies, some alloys of soft and more fusible metals are poured into molds.

Secondly, if you pour the metal into an open mold, the top side will remain flat. Bronze swords were indeed cast, but in closed molds, consisting, as it were, of two halves - not a flat saucer, but a deep and narrow glass.

Thirdly, in the movie it is meant that after hardening the sword already has its final shape and, in general, is ready. However, the material obtained in this way, without further processing by forging, will be too fragile for weapons. Bronze is more ductile and softer than steel; everything is fine with cast bronze blades. But the steel billet will have to be forged long and hard, radically changing its size and shape. This means that the workpiece for further forging should not have the shape of the finished product.

In principle, you can pour molten steel into the form of a workpiece with the expectation of further deformation from forging, but in this case the distribution of carbon inside the blade will turn out to be very uniform or, at least, difficult to control - as much liquid as was in the frozen area, so much will remain. In addition, let us remember that completely melting steel is a very non-trivial task, one that few people solved in pre-industrial times. That's why no one did that.

Composite steel: output

The technological elements of composite steel production are not something complicated or secret. The main advantage of using these technologies is that they compensate for the shortcomings of the source material, making it possible to obtain a completely usable sword from low-quality traditional steel. There are many options for assembling a sword, more and less successful.

Types of composite steel

Composite steel is an excellent solution that allows you to assemble a very high-quality sword from mediocre starting materials. There are other solutions, but we'll talk about them later. Now let's figure out where and when composite steel was used, and how exclusive is this technology for Japanese swords?

Quite a lot of examples of ancient steel swords from Northern Europe have survived to the present day. We are talking about truly ancient weapons, made 400-200 BC. These are the times of Alexander the Great and the Roman Republic. The Yayoi period began in Japan, bronze blades and spear tips were in use, social differentiation appeared and the first proto-state formations arose.

Research into these ancient Celtic swords has shown that hammer welding was in use even back then. At the same time, the distribution of hard and soft material was quite diverse. Apparently this was an era of empirical experimentation, since it was not entirely clear which options were more useful.

For example, one of the options is completely wild. The central part of the sword was a thin strip of steel, onto which strips of iron were riveted on all sides, forming the surface planes and the blades themselves. So yes, a hard core with soft blades. This can only be explained by the fact that the soft blade is easy to straighten with a hammer at rest, and the hard core, made of steel with still not too much carbon content, keeps the sword from deforming. Or the fact that the blacksmith was not himself.

But more often, Celtic blacksmiths simply haphazardly folded strips of iron and mild steel, or did not bother with multi-layering at all. At that time, too little knowledge was accumulated to form specific traditions. For example, no traces of hardening were found, and this is a very important point in the production of a high-quality sword.

In principle, we could end here on the issue of the exclusivity of composite steel for Japanese swords. But let's continue, the topic is interesting.

Roman swords

Roman writers mocked the quality of Celtic swords, claiming that their domestic ones were much cooler. Surely not all of these statements were based solely on propaganda. Although, of course, the successes of the Roman military machine were mainly due not to the quality of equipment, but to general superiority in training, tactics, logistics, and so on.

Composite steel was, of course, used in Roman swords, and in a much more orderly manner than in Celtic ones. There was already an understanding that the blade should be rather hard, and the core should be rather soft. In addition, many Roman swords were hardened.

At least one blacksmith working around 50 AD used all the components of a perfect composite steel in his production. He selected different types of steel, homogenized them by multi-layer hammering, intelligently collected strips of hard and soft steel, forged it well into one product, knew how to harden and either used tempering or hardened very precisely, without overdoing it.

The Yayoi period continued in Japan. About 700-900 years passed before the original traditions of producing steel swords of the Japanese type known to us appeared there.

The traditions of producing Roman swords, despite the presence of all the necessary knowledge, were not perfect at the beginning of our era. There was a lack of some kind of systematicity, an explanation for the results of empirical observations. This was not engineering work, but almost biological evolution with mutations and culling of unsuccessful results. Nevertheless, taking all this into account, the Romans produced very high-quality swords for several centuries in a row. The barbarians who conquered the Roman Empire adopted and subsequently improved their technology.

Somewhere between 300 and 100 BC, Celtic blacksmiths developed a technology called pattern welding. Many swords have come down to us from Northern Europe, made in 200-800 AD in Northern Europe using this technology. Pattern welding was used by both the Celts and Romans, and, later, almost all residents of Europe. Only with the advent of the Viking era did this fashion end, giving way to simple and practical products.

Swords forged with pattern welding look very unusual. In principle, it is quite easy to understand how to achieve such an effect. We take several (many) thin rods consisting of different types of steel. They may vary in the amount of carbon, but the best visual effect comes from adding phosphorus to some of the rods: this steel turns out whiter than usual. We collect this thing into a bundle, heat it and twist it into a spiral. Then we make a second similar bundle, but we launch the spiral in the other direction. We cut the spirals into parallelepiped bars, weld them by forging and give them the desired shape, flattening them. As a result, after polishing, parts of rods of one type or another will appear on the surface of the sword - respectively, of different colors.

But actually doing such a thing is very difficult. Especially if you are not interested in chaotic stripes, but in some beautiful ornament. In fact, not just any rods are used, but pre-packaged (folded and forged a dozen times) thin layers of different grades of steel, carefully assembled into a kind of layer cake. On the sides of the final structure, rods of ordinary hard steel are riveted to form the blades. In particularly advanced cases, several flat plates with ornaments were made, which were riveted to the core of the blade made of medium steel. And so on.

It looked very colorful and joyful. There are a lot of technical nuances that are not important for understanding the general essence, but are necessary for the production of a real product. One mistake, one element of metal in the wrong place, one extra blow with a hammer that spoils the drawing - and everything is lost, the artistic intent is ruined.

But one and a half thousand years ago they somehow managed.

The influence of pattern welding on the properties of a sword

It is now believed that this technology does not provide any advantages over conventional high-quality composite steel, other than aesthetic ones. However, there is one significant caveat.

Obviously, creating a sword decorated with pattern welding is much more expensive and labor-intensive than making just an ordinary sword, even one with a full-fledged compositional assembly, but without all these decorative bells and whistles. So, this complication and rise in price of the product led to the fact that blacksmiths behaved much more carefully and thoughtfully when making weapons with pattern welding. The technology itself does not provide any advantages, but the fact of its use led to increased control at all stages of the process.

It’s not particularly scary to ruin an ordinary sword; anything can happen in production; a certain percentage of defects is acceptable and inevitable. But to screw up a job that went into a blade with pattern welding is a shame. That is why swords with pattern welding were, on average, of higher quality than ordinary swords, and the technology of pattern welding itself had only an indirect relationship to quality.

This same nuance should be kept in mind when it comes to any such fancy technology that magically improves the quality of a weapon. Most often, the secret is not in decorative tricks, but in increased quality control.

It's no secret that people often use certain words without understanding their meaning. For example, the so-called “Damascus” or “Damascus” steel has nothing to do with the capital of Syria. Someone illiterate once decided something for himself, and others repeated it. The version “blades made of steel of this variety came to Europe from Syria” does not stand up to criticism, since steel of this variety would not surprise anyone in Europe.

What is meant by “Damascus”?

In most cases - variations on the theme of patterned weaving. It is not at all necessary to stop at a “puff pastry” of thin layers of steel with different contents of carbon and phosphorus. Blacksmiths in different parts of the world came up with very diverse ways to achieve a beautiful visual effect on the surface of expensive blades. For example, in modern times, when they want to get “Damascus”, they usually do not use phosphorus steel and soft iron, since these materials are not very good. Instead, you can take normal carbon steel and add manganese, titanium and other alloying additives. Steel, alloyed with understanding and/or according to a competent recipe, will not be worse than ordinary carbon steel, but may differ visually.

Speaking about the quality of weapons made from such steel, we remember the reasons for the high quality of swords with pattern welding. Expensive, beautiful swords were made carefully and carefully. It would be possible to make the same quality sword out of "regular" steel, without all those beautiful patterns, but it would be harder to sell for very big money.

Bulat

There are probably no fewer legends associated with damask steel than with Japanese swords. And even more. Absolutely unimaginable properties are attributed to it, and it is believed that no one knows the secrets of its manufacture. An unprepared mind, when confronted with such tales, becomes foggy and begins to wander dreamily, in especially difficult cases reaching ideas like “I wish I could learn how to make damask steel and make tank armor from it!”

Bulat is a crucible steel made in ancient times using various tricks to bring the iron-carbon mixture to melt and not turn it into cast iron. Crucible means completely melted in a crucible, a ceramic pot that isolates it from fuel decomposition products and other contaminants inside the furnace.

It is important. Damask steel, unlike “ordinary” steel, is not simply somehow restored from oxides by prolonged baking, like Tamahagane and other ancient types of steel from cheese-blowing furnaces, but brought to a liquid state. Complete melting makes it easy to get rid of unwanted impurities. Almost everyone.

The iron-carbon diagram is indispensable here. We are not interested in all of it now, we are only looking at the top part.

The curved line going from A to B and then to C indicates the temperature at which the iron-carbon mass completely melts. Not just iron, but iron with carbon. Because, as can be seen from the diagram, when carbon is added up to 4.3% (eutectic, “easy melting”), the melting point drops.

Ancient blacksmiths could not heat their stoves to 1540° C. But up to 1200° C was enough. But it is enough to heat iron with 4.3% carbon to approximately 1150 ° C to obtain a liquid! But, unfortunately, when solidified, the eutectic mixture is completely unsuitable for the production of swords. Because what you get is not steel, but brittle cast iron, from which you can’t even forge anything - it simply breaks into pieces.

But let’s take a closer look at the process of solidification of liquid steel itself, that is, crystallization. Here we have a pot, closed with a lid with a small hole for venting gases. A molten mixture of iron and carbon splashes in it in a proportion close to eutectic. We took the pot out of the oven and left it to cool. If you think a little, it will become obvious that the solidification will be uneven. First, the pot itself will cool, then the part of the melt adjacent to its walls will cool, and only gradually the solidification and formation of crystals will reach the center of the mixture.

Somewhere near the inner wall of the pot, an irregularity occurs and a crystal begins to form. This happens at many points at once, but we are now concerned about one, any of them. It is the eutectic mixture that hardens most easily, but the distribution of carbon in the mixture is not entirely uniform. And the hardening process makes it even less uniform.

Let's look at the diagram again. From point C, the melting line goes both to the right, to D - the melting point of cementite - and to the left, to B and A. When a certain area solidified first, it can be assumed that it was the eutectic proportion that solidified. The crystal begins to spread, “absorbing” the easily solidifying mixture with 4.3% carbon.

But in addition to the eutectic regions, our melt also contains regions with a different proportion, more refractory. And, if we haven’t gone too far with carbon, then it’s more likely that these will be more refractory areas with less carbon content than vice versa. Moreover: the solidifying crystal “steals” carbon from neighboring areas of the molten mixture. Therefore, as a result, the further away from the walls of the vessel, the less carbon there will be in the frozen pig.

Unfortunately, if you do everything as is, you will still end up with cast iron, from which it is not possible to isolate possible small areas of steel suitable for forging. But you can be more cunning. There are so-called fluxes or fluxes, substances that, when added to a mixture, reduce its melting point. Moreover, some of them, such as manganese, in reasonable proportions are an additive that improves the properties of steel.

Now there is hope! And rightly so. So, we take the iron obtained previously in a cheese-blowing oven like the same Tatara that everyone had. We crush it as finely as possible. Ideally, it would be reduced to a state of dust, but this is very difficult to achieve with ancient technologies, so it is as it is. We add carbon to the iron: you can use either ready-made coal or unburned plant matter. Don't forget the correct amount of flux. We distribute all this in a certain way inside the crucible pot. How exactly depends on the recipe, there may be different options.

Using these and some other tricks, after melting and proper cooling in the central part of the crucible mass, the carbon content can be increased to 2%. Strictly speaking, it's still cast iron. But with the help of certain tricks, which are completely unnecessary to talk about here, ancient metallurgists obtained interesting structures for the distribution of crystals in this 2% material, which made it possible, with certain difficulties and precautions, to forge swords from it.

This is damask steel - very hard, very brittle, but much more durable than cast iron. Containing virtually no unnecessary impurities. In comparison with raw steel such as Tamahagane, yes, damask steel had certain interesting properties, and a specially trained blacksmith could create an impressive weapon from it. Moreover, this weapon, like almost all swords since Celtic times, was composite, including not only crucible damask steel, but also good old strips of relatively soft material.

More advanced smelting processes, which can heat the furnace to 1540°C or higher, simply eliminate the need for damask steel. There is nothing mythical about it. In the 19th century in Russia it was produced for some time, out of historical nostalgia, and then abandoned. Now it is also possible to produce it, but no one really needs it.

Carolingian-type swords, often called Viking swords, were common throughout Europe from 800 to about 1050. The name “Viking sword,” which has become a commonly used term in modern times, does not correctly convey the origin of this weapon. The Vikings were not the authors of the design of this sword - it logically evolves from the Roman gladius through the spatha and the so-called Wendel-type sword.

The Vikings were not the only users of this type of weapon - it was distributed throughout Europe. And finally, the Vikings were not seen either in the mass production of such swords, or in the creation of any particularly outstanding specimens - the best “Viking swords” were forged in the territory of future France and Germany, and the Vikings preferred imported swords. They imported, of course, robbery.

But the term “Viking sword” is common, understandable and convenient. Therefore, we will use it too.

Pattern welding was not used in swords of this era, so compositional assembly became easier. But it was not degradation, but the opposite. Viking swords were made entirely of carbon steel. Neither soft iron nor steel with a high phosphorus content was used. Forging technologies had already reached perfection during the period of pattern welding, and there was nowhere to develop in this direction. Therefore, development moved towards improving the quality of the source material - technologies for producing the steel itself developed.

During this era, weapon hardening became widespread. Early swords were also hardened, but not always. The problem was the material. All-steel blades made from high-quality prepared metal could already be guaranteed to withstand hardening according to some reasonable recipes, whereas in earlier times the imperfection of the metal could fail the blacksmith at the very last moment.

The blades of Viking swords differed from older weapons not only in material, but also in geometry. The fuller was used everywhere to lighten the sword. The blade had a lateral and distal narrowing, that is, it was narrower and thinner near the tip and, accordingly, wider and thicker near the cross. These geometric techniques, combined with more advanced material, made it possible to make a solid all-steel blade quite strong and at the same time light.

In the future, composite steel in Europe did not disappear anywhere. Moreover, from time to time, long-forgotten pattern welding emerged from oblivion. For example, in the 19th century, a kind of “renaissance of the early Middle Ages” arose, within the framework of which even firearms, not to mention bladed ones, were made by pattern welding.

So what's in Japan? Nothing special.

Fragments of the future workpiece are packaged from pieces of steel coins with different carbon contents. Then a blank of one or another composition is assembled and given the desired shape. Next, the blade is hardened and then polished - we'll talk about these steps later. Moreover, if we measure manufacturability, then in terms of the “technological level” of the material, damask steel beats everyone, including the Japanese. In terms of assembly perfection, pattern welding is no worse, if not better.

At the stage of assembly and actual forging of the sword, there is no specificity that makes it possible to distinguish Japanese blades from the weapons of other cultures and eras.

Composite steel: another conclusion

Steel baling, which produces a homogeneous material with an acceptable quantity and distribution of slag, has been used throughout the world almost since the beginning of the Iron Age. A well-thought-out composite blade assembly appeared in Europe no later than two thousand years ago. It is the combination of these two techniques that gives the legendary “multi-layer steel”, from which, of course, Japanese swords are made - like many other swords from all over the world.

Quenching and tempering

After a blade has been forged from one steel or another, the work on it is not completed. There is a very interesting way to obtain a material much harder than ordinary perlite, from which the blade of a more or less perfect sword is made. This method is called hardening.

You've probably seen in movies how a hot blade is dipped into a liquid, it hisses and boils, and the blade quickly cools down. This is what hardening is. Now let's try to understand what happens to the material. We can look again at the already familiar iron-carbon diagram, this time we are interested in the lower left corner.

For further hardening, the blade steel must be heated to an austenitic state. The line from G to S represents the austenite transition temperature of normal steel, without too much carbon. It can be seen that further from S to E the line grows steeply upward, that is, with excessive addition of carbon to the composition, the task becomes more complicated - but in almost any case this is already excessively brittle cast iron, so we are talking about lower concentrations of carbon. If the steel contains from 0 to 1.2% carbon, then the transition to the austenitic state is achieved at temperatures up to 911 ° C. For a composition with a carbon content of 0.5 to 0.9%, a temperature of 769 ° C is sufficient.

In modern conditions, measuring the temperature of a workpiece is quite easy - there are thermometers. In addition, austenite, unlike ferrite, is not magnetic, so you can simply apply a magnet to the workpiece and, when it stops sticking, it will become clear that this is steel in the austenitic state. But in the Middle Ages, blacksmiths did not have thermometers or sufficient knowledge about the magnetic properties of the various phases of steel. Therefore, we had to measure the temperature by eye in the literal sense of the word. A body heated to a temperature above 500° C begins to emit radiation in the visible spectrum. Based on the color of the radiation, it is quite possible to approximately determine body temperature. For steel heated to austenite, the color will be orange, like the sun at sunset. Due to these subtleties, hardening, which included preheating, was often carried out at night. In the absence of unnecessary lighting sources, it is easier to determine by eye whether the temperature is sufficient.

The differences between the crystal lattices of austenite and ferrite have already been discussed in one of the previous articles in the series. Briefly: austenite is a face-centered lattice, ferrite is a body-centered lattice. Taking into account thermal expansion, austenite allows carbon atoms to travel within its crystal lattice, whereas ferrite does not. It has also already been discussed what happens during slow cooling: austenite quietly transforms into ferrite, while the carbon inside the material disperses into strips of cementite, resulting in pearlite - ordinary steel.

And now we finally get to hardening. What happens if you don't give the material time to cool slowly at the usual rate of carbon on the cementite strips in perlite? So, let’s take our workpiece, heated to austenite, and put it in ice water, just like in the movies!..

...Most likely the result will be a split workpiece. Especially if we use traditional steel, that is, imperfect, with a bunch of impurities. The reason is extreme stresses resulting from thermal compression that the metal simply cannot cope with. Although, of course, if the material is clean enough, then you can put it in ice water. But traditionally, they often used either boiling water, so as not to drop the temperature too low, or even boiling oil. The temperature of boiling water is 100° C, oil is from 150° to 230° C. Both are very cool compared to the temperature of the austenitic workpiece, so there is nothing paradoxical in cooling with such hot substances.

So, let’s imagine that everything is fine with the quality of the material, and the water is not too cold. In this case the following will happen. Austenite, inside which carbon travels, will immediately turn into ferrite, while no delamination into pearlite strips will occur; carbon at the microlevel will be distributed quite evenly. But the crystal lattice will not be the usual smooth cubic one for ferrite, but wildly broken due to the fact that it is simultaneously formed, compressed by cooling and has carbon inside.

The resulting variety of steel is called martensite. This material, full of internal stress due to the peculiarities of the lattice formation, is more fragile than pearlite with the same carbon content. But martensite is significantly superior to all other types of steel in terms of hardness. It is from martensite that tool steel is made, that is, tools designed to work on steel.

If you look closely at the cementite in the composition of perlite, you will notice that its inclusions exist separately and do not touch each other. In martensite, the crystal lines are intertwined like wires from headphones that have been in your pocket all day. Pearlite is flexible because areas of hard cementite dissolved in soft ferrite simply move relative to each other when bent. But in martensite nothing like this happens; the regions cling to each other - therefore it is not prone to changing shape, that is, it has high hardness.

Hardness is good, but brittleness is bad. There are several ways to compensate for or reduce the brittleness of martensite.

Zone hardening

Even if you temper the sword exactly as described above, the blade will not be entirely made of homogeneous martensite. The blade (or blades, for a double-edged sword) cool quickly due to its thinness. But the blade in the thicker part, be it the back or the middle, cannot cool at the same rate. The surface is fine, but the inside is no longer there. However, this alone is not enough; anyway, a weapon hardened in this way without additional tricks turns out to be too fragile. But since the cooling is not uniform, you can try to control its speed. And this is exactly what the Japanese did, using zonal hardening.

A workpiece is taken - of course, already with the correct compositional assembly, formed blade, and so on. Then, before heating for further hardening, the workpiece is coated with a special heat-resistant clay, that is, a ceramic composition. Modern ceramic compositions can withstand temperatures of thousands of degrees in the solid state. The medieval ones were simpler, but the temperature was also needed lower. No exotic stuff is required, it’s almost ordinary clay.

The clay is applied unevenly to the blade. The blade is either left without any clay at all, or is covered with a very thin layer. The side planes and back, which do not need to turn into martensite, on the contrary, are coated with all their hearts. Then everything is as usual: heat it up and cool it down. As a result, a blade without thermal insulation will cool very quickly, turning into martensite, and everything else will easily form pearlite or even ferrite, but this already depends on the types of steel used in the assembly.

The resulting blade has a very hard edge, the same as if it were made entirely of martensite. But, due to the fact that most weapons consist of perlite and ferrite, they are much less fragile. In the event of an inaccurate blow or in a collision with something excessively hard, a pure martensite blade can break in half, because there is too much stress inside it, and if you overdo it a little, the material simply will not withstand it. A Japanese-type sword will simply bend, perhaps with the appearance of a dent on the blade - a piece of martensite will still break, but the blade as a whole will retain its structure. It is not very convenient to fight with a bent sword, but it is better than with a broken one. And then it can be straightened out.

Let us dispel the myth about the exclusivity of zone hardening: it is found on ancient Roman swords. This technology was generally known everywhere, but it was not always used because there was an alternative.

Jamon

A distinctive feature of Japanese swords, made and polished in the traditional way, is the hamon line, that is, the visible border between different types of steel. Zone hardening professionals knew how and are able to make jamon of various beautiful shapes, even with ornaments - the only question is how to mold the clay.

Not every good sword, or even every Japanese sword, has visible hamon. It cannot be seen without a specific procedure: special “Japanese” polishing. Its essence lies in the consistent polishing of the material with stones of varying hardness. If you simply polish everything with something very hard, then it will be impossible to distinguish any jamon, since the entire surface will be smooth. But if after this you take a stone that is softer than martensite, but harder than ferrite, and polish the surface of the blade with it, then only ferrite will be ground off. Martensite will remain intact, but pearlite may retain convex lines of cementite. As a result, the surface of the blade at the micro level ceases to be perfectly smooth, creating a play of light and shadows that is aesthetically pleasing.

Japanese polishing in general and hamon in particular have no effect at all on the quality of the sword.

Tempering and spring steel

Due to its structure, martensite has a large number of internal stresses. There is a way to relieve these tensions: vacation. Tempering is the heating of steel to a much lower temperature than the one at which it turns into austenite. That is, up to approximately 400° C. When the steel turns blue, it is heated enough, tempering has occurred. Then it is allowed to cool slowly. As a result, the stresses partially disappear, the steel acquires ductility, flexibility and springiness, but loses hardness. Therefore, spring steel cannot be as hard as tool steel - it is no longer martensite. And, by the way, this is why overheated instruments lose their hardening.

Spring steel is called such because it is used to make springs. Its main distinguishing property is elasticity. The blade, made of high-quality spring steel, bends upon impact, but immediately returns to its shape.

Flexible, springy swords are monosteel - that is, they consist entirely of steel, without pure ferrite inserts. Moreover, they are completely hardened to martensite and then completely tempered. If the structure of the blade before hardening includes fragments not made of martensite, then it will not be possible to make a spring.

A Japanese sword usually has such fragments: pearlite along the planes and ferrite in the middle of the blade. In general, it is mainly made of iron and mild steel; there is quite a bit of martensite there, only on the blade. So no matter how you harden the katana and don’t release it, it won’t spring back. Therefore, a Japanese sword either bends and remains bent, or breaks but does not spring, like a European monosteel tempered martensite blade. A slightly bent katana can be straightened without significant consequences, but often pieces of the martensite blade simply break off when bent, forming jagged edges.

The katana, unlike the European blade, is not at least fully tempered, so its blade retains hard martensitic steel, with a hardness of about 60 Rockwell. And the steel of a European sword can be in the region of 48 Rockwell.

There are several traditional ways to form the layered structure of a Japanese sword. Two of them do not use ferrite. The first is maru, which is simply hard high-carbon steel all over the blade. Of course, such a sword requires local hardening, otherwise it will break at the first blow. The second is warha tetsu, where the body of the blade, with the exception of the tip, consists of medium-hard steel, that is, perlite.

Why weren’t maru and warha tetsu made springy? It is not known exactly. Maybe in Japan they didn’t even know about the tempering properties of steel. Or they simply did not consider it necessary to make swords springy. We should not forget that for Japan, even more than for the rest of the world, following traditions was important. A significant number of variations in the design of Japanese (and not only) swords does not make any sense from a practical point of view, pure aesthetics. For example, a wide fuller on one side of the blade and three narrow fullers on the other side, or in general swords with asymmetrical geometry on the cut. Not everything can and should be explained rationally, in relation to the battle itself.

Modern blacksmiths make Japanese-style swords with a spring base blade and a martensite blade. The most famous is the American Howard Clark, who uses L6 steel. The base of his swords is made of bainite rather than pearlite and ferrite. The blade, of course, is martensitic. Bainite is a steel structure that was not discovered until 1920; it has high hardness and strength with high ductility. Spring steel is bainite or something close to it. Despite all the external similarities with the Nihonto, such a weapon can no longer be considered a traditional Japanese sword; it is of much higher quality than historical prototypes.

In a monostal sword you can also differentiate by hardness zones. If, after hardening, the martensitic workpiece is not tempered evenly, but by heating only the plane of the blade directly, then the heat reaching the edges will be insufficient to transform the martensitic blades into spring steel. At least in the modern production of knives and some tools, similar tricks are used. It is unknown how the increased fragility of the blades of such weapons will affect practice.

What is better: high hardness without flexibility or a decrease in hardness with the acquisition of flexibility?

The main advantage of a hard blade is that it holds an edge better. The main advantage of a flexible blade is the increased likelihood of its survival when deformed. When hitting a target that is too hard, the katana blade is likely to break off, but thanks to the softness of the rest of the blade, the sword will not break; rather, it will simply bend. If a monostal flexible blade breaks, it is usually in half - but breaking it with adequate use is very difficult.

Theoretically, hard steel should be able to cut through more materials than soft steel, but in practice, bones can be easily chopped with European swords, and armor steel cannot be pierced by any chopping sword.

If we talk about working with a blade against plate armor, then no one will cut anything there: they will stab into areas of the body unprotected by armor, which are still covered with at least a gambeson, or even chain mail. The very high flexibility of a spring blade is not suitable for thrusting, but special European swords for fighting against plate armor were not flexible. They, on the contrary, were equipped with additional stiffening ribs. That is, special anti-armor swords have always been inflexible, no matter what steel they were made of.

In my opinion, in battle it is better to have a stronger sword that is difficult to damage. It’s not so important that it cuts a little worse than a harder one. A hard, zone-hardened blade may be more useful in calm, controlled situations, such as tameshigiri, when there is plenty of time to aim and no one is trying to hit the sword from the weak side.

Quenching and tempering: conclusion

The Japanese had the technology of hardening, which was also known in Ancient Rome from the beginning of our era. There is nothing extraordinary about zonal hardening. In medieval Europe, they used a different technology to combat the fragility of steel, deliberately abandoning zonal hardening.

The blade of a Japanese sword is harder than that of most European ones - that is, it does not need to be sharpened as often. However, with active use, it is highly likely that the Japanese sword will have to be repaired.

Design and geometry

From a practical point of view, it is important that the sword is good enough. It must perform the tasks for which it was created - be it priority on slashing power, improved thrusts, reliability, durability, and so on. And when it's good enough, it doesn't really matter how it's made.

Statements like “a real katana must be made in the traditional way” are unfair. The Japanese sword has certain characteristics, including advantages. It doesn’t matter how these benefits are achieved. Yes, the Japanese style bainite swords from Howard Clark are not traditionally made katanas. But they are certainly katanas in the broad sense of the word.

It's time to move on to the more commonly discussed aspects of the sword, such as blade geometry, balance, hilt, and so on.

Slash Effectiveness

The katana is famous for being good at cutting things. Of course, based on this simple fact, fanatics create an entire mythology, but we will not become like them. Yes, it’s true - a katana cuts things well. But what does “good” even mean? Why does Nihonto cut things well, compared to what?

Let's start in order. What is “good” is a somewhat philosophical question, it smacks of subjectivity. In my opinion, this is what good chopping qualities are made of:

With a weapon it is enough to simply deliver an effective blow; even a person without training will be able to cut through a target of low complexity.
Cleaving does not require enormous force and/or impact energy, it is based on the sharpness of the warhead and precisely on dividing the target into two parts, and not on tearing.
If used properly, the weapon is unlikely to fail, meaning it is quite durable. It is advisable, of course, to have a margin of safety even for not very correct operation. When a sword is carried around like a sack, it is not as impressive as when a tree is cut down with a few careless blows.
It is really very easy to cut with a Japanese sword. The reasons will be discussed below, but for now let’s just remember this fact. I note that a significant portion of the mythologization of Japanese swords stems from it. For an inexperienced but diligent person, all other things being equal, it will be easier to cut a target with a katana than with a European long sword, simply because the katana is more patient with small mistakes. An experienced practitioner will not notice much of a difference.

For cutting itself, and not tearing the target, you need to have a fairly sharp cutting edge. Here the Japanese sword is in perfect order. Sharpening using traditional Japanese methods is very advanced. In addition, a martensite blade, when sharpened, retains its sharpness for quite a long time, although this rather relates to the next point. However, it should be noted that a sword, even without a martensite blade, can be sharpened and made very sharp. It will just become dull faster, meaning it will need to be re-sharpened sooner. In any case, the number of blows after which a sword needs to be sharpened is measured in tens and hundreds, so from a practical point of view, in a single episode, the hardness of a martensite blade does not give anything special, since two freshly sharpened swords will be used for a hypothetical comparison.

But the durability of the Japanese sword is much worse than that of its European counterparts. Firstly, from a sufficiently strong blow to an excessively hard surface, the martensite blade will simply break off, leaving a notch on the blade. Secondly, with a combination of excessive force and low accuracy of the blow, you can bend the sword without any problems even when hitting a fairly soft target. Thirdly, the stresses inside the material are such that a Japanese sword still has high strength when struck with the blade forward, but when struck in the back it has every chance of breaking, even if the blow seems very weak.

Voltages

To understand what stress is, let's conduct a thought experiment. You can also look at its schematic representation in the illustration. Let's imagine a rod made of no matter what material - let it be an elastic tree. Let's place it horizontally, secure the ends and leave the middle hanging in the air. A kind of letter “H”, where the horizontal jumper is our rod. The vertical columns are not fixed too rigidly; they can bend towards each other. (Position 1).

If we neglect gravity, which can be done since the rod is very light, then the stresses in the rod material known to us are small. If they exist, they clearly balance each other. The rod is in stable condition.

Let's try to bend it in different directions. The columns between which it is secured will bend towards the rod, but if you release it, it will return to the starting position, pushing the columns to the sides. If we do not bend it too much, then nothing special will happen from such deformations, and, more importantly, we do not feel any difference between which way we bend the rod. (Position 2).

Now let's hang a significant weight from the middle of the rod. Under its weight, the rod will be forced to bend towards the ground and remain in this state. Now there is obvious tension in our rod: its material “wants” to return to a straight state, that is, to bend from the ground, in the direction opposite to the bend. But he can’t, the load is in the way. (Position 3).

If you apply sufficient force in this direction, opposite to the load and corresponding to the direction of stress, the rod can straighten. However, as soon as the force is stopped, it will return to its previous bent state. (Position 4).

If you apply a relatively small force towards the load, opposite to the direction of the stress, the rod may break - the stress will have to escape somewhere, the strength of the material will no longer be enough. In this case, the same or even much more powerful force in the direction of stress will not lead to damage. (Position 5).

It's the same with the katana. The impact in the direction from the blade to the back goes in the direction of stress, “lifting the load” and, one might say, temporarily relaxing the material of the blade. The impact from the back to the blade goes against the tension. The strength of the weapon in this direction is very low, so it can easily break, like a rod on which too much weight is hung.

Again the effectiveness of the slash

Let's return to the previous topic. Let's now try to figure out what is needed in principle to cut a target.

It is necessary to strike correctly orientated.
The blade of the sword must be sharp enough to cut the target, and not just crush and move it.
You need to give the blade a sufficient amount of kinetic energy, otherwise you will have to cut, not chop.
You need to put enough force into the blow, which is achieved both by accelerating the blade and making it heavier, including through optimizing the balance for chopping, perhaps even to the detriment of other qualities.

Blade orientation upon impact

If you've ever tried tameshigiri, that is, chopping objects with a sharp sword, then you should understand what we're talking about. The orientation of the blade upon impact is the correspondence between the plane of the blade and the plane of impact. Obviously, if you hit a target with a plane, it definitely won’t be cut, right? So, much smaller deviations from the ideally accurate orientation already lead to problems. That is, when attacking with a sword, it is necessary to monitor the orientation of the blade, otherwise the blow will not be effective. With batons this question does not arise, it doesn’t matter which side to hit - but the blow will turn out to be impact-crushing, and not chopping-cutting.

In general, let's compare bladed and impact-crushing weapons, without being tied to specific samples. What are their mutual advantages and disadvantages?

Advantages of the sword:

A slash to a part of the body that is not protected by armor is much more dangerous than just a bludgeon. Although a club (a club with spikes) and a mace (a metal club with a developed warhead) cause significant damage, a sword is still more dangerous.
Usually there is a somewhat developed hilt that protects the hand. Even a cross or tsuba is better than a completely smooth handle.
Geometry and balance, coupled with sharpness, allow the weapon to be made comparatively longer without becoming overweight or losing impact power. A knight's sword and a mace of the same mass differ in length by one and a half to two times. You can make a long, light club, but a blow with it will be much less dangerous than a blow with a sword.
Significantly better stabbing capabilities.
Advantages of the baton:

Easy to manufacture and low cost. This is especially true for primitive clubs and clubs.
Developed varieties of impact-crushing weapons (mace, six-fin, war hammer) are specially sharpened for fighting against opponents in armor. A knight's or long sword against a man-at-arms is much less effective than a six-sword.
In the general case, excluding highly specialized war hammers and knives, it is easier to deliver an effective blow to a fairly close target with a club or mace. There is no need to monitor the orientation of the blade upon impact.
Let us again pay attention to the last of the listed advantages of impact-crushing weapons, which, accordingly, is a disadvantage of bladed weapons.

What can be said about the orientation of the blade when striking with a katana? That everything is fine with her.

A slight bend slightly increases the windage of the surface: leading a Japanese sword forward with the plane, and not with the blade or back, is a little more difficult than a straight blade of the same dimensions. Thanks to this windage, air resistance upon impact helps the blade to rotate correctly. To be fair, it should be noted that this effect is very weak and can easily be reduced to insignificance by applying the principle “you have the power, you don’t need the mind.” But if you still use your mind, you should first work the Japanese sword through the air - slowly, then quickly, then slowly again. This will help you feel when he walks without any noticeable resistance at all, cutting through the air, and when something slightly interferes with him.

The Japanese sword has one blade, and the thickness of the blade at the back is quite large. These geometric characteristics, as well as the materials used in nihonto, increase rigidity, that is, “inflexibility.” The katana is a sword that does not bend as easily as its European counterparts, which at some point began to be made from spring steel (bainite) to increase strength.

High rigidity coupled with a very hard blade leads to an interesting effect, which is what makes cutting with a katana so simple. It is clear that upon impact, deviations from the ideal orientation are likely. If deviations are completely or almost absent, then Japanese and European swords cut the target equally well. If the deviations are significant, then neither one nor the other sword will be able to cut the target, and the likelihood of damaging a Japanese sword is higher.

But if there are already deviations, but they are not too large, then the Japanese martensitic-ferritic and European bainite swords behave differently. The European sword will bend, spring back and bounce off the target with virtually no damage - just as if the deflection were higher. In this case, the Japanese sword will cut the target as if nothing had happened. A blade that enters a target at an angle cannot spring back and rebound due to its hardness and rigidity, so it bites at the angle at which it can, and even corrects the orientation of the blade to some extent.

Once again: this effect only works for small mistakes. It is better to deal a really bad blow with a European sword than with a Japanese one - he is more likely to survive.

Blade sharpening

The sharpness of the blade depends on the angle at which the cutting edge is formed. And here the Japanese sword has a potential advantage over the European double-edged sword - however, like any other single-edged blade.

Take a look at the illustration. It shows sections of the profiles of various blades. All of them (with obvious exceptions) can be fit into a 6x30 mm rectangle, that is, the blades at the point of cutting and analysis have a maximum thickness of 6 mm and a width of 30 mm. In the top row there are sections of one-sided blades, for example, nihonto or some kind of saber, and in the bottom row - double-edged swords. Now let's delve into it.

Look at swords 1, 2 and 3 - which one is sharper? It is quite obvious that 1, because the angle of its cutting edge is the most acute. Why is that? Because the edge is formed as much as 20 mm before the blade. This is a very deep sharpening and is used quite rarely. Why? Because this sharp blade becomes too fragile. When hardened, you will end up with more martensite than you would want to have on a sword designed to last more than one blow. Of course, it is possible to correct the formation of martensite using ceramic insulation during hardening, but such a cutting edge will still be less strong than duller options.

Sword 2 is already a normal, more durable option, which you don’t need to worry about with every blow. Sword 3 is very good, a reliable tool. There is only one drawback: he is still quite stupid and nothing can be done about it. More precisely, something can be done by sharpening it, but the reliability will just go away. Swords 2 and especially 1 are good for cutting targets at tameshigiri competitions, and sword 3 is good for training before competitions. It’s hard to study, but it’s easy to “combat”, where by combat we mean competition. If we talk about fighting with military weapons, then sword 3 is again preferable, since it is much stronger than 2 and especially 1. Although sword 2 can perhaps be considered something universal, much more serious research must be carried out before to say this.

The most interesting thing about sword 3 is the blue narrowing lines of the blade, which are not yet a cutting edge. If they were not there, and the edge remained the same short, 5 mm, then its angle would be 62°, and not a more or less decent 43°. Many Japanese and other swords are made using a similar taper, turning into a “blunted” blade, as this is an excellent way to make a weapon at the same time quite light, reliable and not too dull. A blade with an edge length of not 5, but at least 10 mm, like sword 2, with the same narrowing to 4 mm at the beginning of the blade will already have a sharpness of 22° - not bad at all.

Sword 4 is an abstraction, a geometrically sharpest blade within given dimensions. Has all the problems of Sword 1 in a more severe form. Sharp, yes, you can’t take that away, but extremely fragile. It is unlikely that a martensitic-ferritic structure will withstand such a geometry. If you take spring steel, it might hold up, but it will dull very quickly.

Let's move on to double-edged blades. Sword 6 is a Viking-type blade made in the dimensions specified above, having the profile of a flattened hexagon with fullers. The fullers do not have any effect on the sharpness of the blade; they are shown in the illustration for a certain integrity of the images. So, in terms of sharpness, this blade corresponds to one-sided sword 2. Which is not so bad. What's even better is that historically Viking-type swords had completely different proportions, being thinner and wider - as can be seen in sword 7, which is as sharp as sword 1. Why is this so? Because instead of the martensitic-ferritic structure, other materials are used here. Sword 6 will dull faster than sword 1, but it is less likely to break.

The disadvantage of sword 6 is its very low rigidity - it is the most flexible of the blades presented here. Excessive flexibility interferes with a slashing blow, but you can live with it, but with a piercing blow it is of no use at all. Therefore, in the late Middle Ages, the profile of the blade changed to a rhombic one, like that of sword 7. It is more or less sharp, although it does not reach swords 1 and 6. However, unlike sword 6, it is much less flexible. The maximum blade thickness of 6 mm makes it more rigid, which is great when stabbing. Compared to sword 6, sword 7 clearly sacrifices the slashing ability in favor of the piercing one.

Sword 8 has a purely piercing blade. Despite the sharpness of 17°, such a weapon will no longer be able to cut normally. After penetrating the target to a depth of 13 mm, the impact will be slowed down by stiffening ribs that have an angle of as much as 90°. But the mass of this blade is clearly less than that of sword 7, and its rigidity is even higher.

As a result, we have the following consideration: yes, a katana, in principle, can have a very sharp blade due to the geometry of the one-sided blade, which allows you to start sharpening or narrowing not from the middle, but from the back, without losing rigidity. However, martensitic-ferritic blades of Japanese swords do not have sufficient strength qualities to realize the maximum of what the geometry of a single-sided blade is capable of. We can say that the sharpness of a Japanese sword does not exceed a European one - especially when you consider that in Europe there were also single-sided blades, often made from materials more suitable for sharp sharpening.

Kinetic energy

E=1/2mv2, that is, the kinetic energy depends linearly on the mass and quadratically on the impact speed.

The weight of the katana is normal, perhaps a little higher than that of European swords of the same dimensions (and not vice versa). Of course, despite the general external similarity, there are Japanese swords of very different weights, which is not visible in the pictures. But the katana is primarily a two-handed weapon, so the increased mass does not particularly interfere with accelerating the blade to high speed.

Kinetic energy is not a question of the sword, but of its owner. If you have at least basic skills in working with weapons, everything will be fine. Here the Japanese sword does not have any tangible advantages or disadvantages compared to its European counterparts.

Impact force: balance

F=ma, that is, the force depends linearly on mass and acceleration. We've already talked about mass, but we need to add something about balance.

Imagine an object in the shape of a heavy weight on a 1 meter long handle, a kind of mace. Obviously, if you take this object by the end of the handle farthest from the weight, swing it well and hit it with the weight accelerated at the end of the handle-lever, the blow will be strong. If you take this object by the handle right next to the weight and hit it with the empty end, then the force of the blow will be completely different, despite the fact that an object of the same mass is used.

This is because when struck with a hand weapon, not the entire mass of the weapon is converted into force, but only a certain part of it. The balance of the weapon has a significant impact on what this part will be. The closer the balance point, the center of gravity of the weapon, is to the enemy, the more mass can be put into the blow. As m increases, so does F.

However, usually in everyday life “well balanced” refers to swords with a balance close to the owner of the weapon, and not to the enemy. The fact is that a well-balanced sword is much more convenient to fencing. Let's return mentally to our weight on the handle. It is clear that with the first grip option, making high-speed and unpredictable movements with this weapon will be very problematic due to the monstrous inertia. With the second, there are no problems, the massive mace practically does not have to be moved, it will only spin slightly near the fists, and it is not difficult to swing the light empty end.

That is, the optimal balance for chopping and fencing is different. If you need to cause damage, then the balance should be closer to the enemy. If maneuverability is necessary, and the lethality of a weapon is unimportant or, in the case of modern non-lethal modeling, undesirable, then it is better to have the balance closer to the owner.

The katana's balance for chopping is in perfect order. Nihonto tend to have a very massive blade without the significant distal taper typical of many European swords. In addition, they do not have a massive apple and a weighty crosspiece, and these parts of the hilt greatly shift the balance towards the owner. Therefore, fencing with a Japanese sword is somewhat more difficult, since it feels heavier and more inertial compared to a European analogue of identical mass. However, if the question of subtle maneuvers is not raised and you just need to slash powerfully, then the balance of the katana turns out to be more convenient.

Blade bend

Everyone knows that Japanese swords are characterized by a slight curve, but not everyone knows where it comes from. Since the blade cools unevenly during hardening, thermal compression also occurs unevenly. First, the blade cools, and it immediately contracts, so in the first seconds of the hardening process, the blade of the future Japanese sword has a reverse bend, like kukri and other kopis. But after a few seconds, the rest of the blade cools down, and it also begins to bend. It is clear that the blade is thinner than the rest of the blade, meaning there is more material in the middle and on the back. Therefore, as a result, the back of the blade is compressed more than the blade.

By the way, this effect distributes the stress inside the blade of a Japanese sword so that it can handle a blow from the side of the blade normally, but not from the side of the back.

When hardening a double-edged blade, curvature does not appear by itself, because at all phases of this process, compression on one side is compensated by compression on the other side. Symmetry is maintained, the sword remains straight. The katana can also be made straight. To do this, before hardening, the workpiece must be given a compensating reverse bend. There were such swords, but there weren’t too many of them.

It's time to compare straight and curved blades.

Advantages of straight blades:

For the same mass there is a large length, for the same length there is a smaller mass.
Much easier and better to prick. With curved blades you can thrust in an arc, but this is not as fast and common as a straight thrust.
A straight sword is often double-edged. If the hilt is not specialized for one direction of grip, then if the blade is damaged, it is easy to take the sword “back to front” and continue to fight.
Advantages of curved blades:

When delivering a chopping blow to the side surface of a cylindrical target (and a person is a collection of cylinders and similar figures), the more curved the blade is, the more easily the blow turns into a cutting blow. That is, with the help of a curved sword you can deliver a wounding blow by investing less force than is required for a straight sword.
Upon contact, a slightly smaller surface of the blade comes into contact with the target, which increases pressure and allows you to cut past the surface. For penetration depth, this advantage does not matter.
Thanks to the slightly larger windage of the curve, it is easier to move the blade forward, orienting it correctly upon impact.
In addition, both blades have specific fencing capabilities. For example, a curved blade is more convenient to cover in some stances, and its concave back can be used to influence the enemy’s weapon in an interesting way. A straight blade has the ability to strike with a false blade and is controlled somewhat more intuitively. But these are already details, one might say, balancing each other.

The following differences are significant: the advantage of straight blades in terms of weight/length, optimization of the delivery of injections and, accordingly, the advantage of curved blades in terms of ease of delivering an effective cutting blow. That is, if you need to specifically inflict damage with slashing blows, then a curved blade is better than a straight one. If you rather fencing in a non-lethal simulation, where “damage” is taken into account very conditionally, then it will be more convenient to work with a straight blade. Let me note that this does not mean that a straight blade is a game and training weapon, and a curved one is a real combat weapon. Both can fight and train, it’s just that their strengths manifest themselves in different situations.

A Japanese sword usually has a very slight curve. Therefore, oddly enough, in some sense it can generally be considered direct. It is quite convenient for them to stab in a straight line, although with a rapier, of course, it is better. There is usually no sharpening on the reverse side, but various types of broadswords may not have one. The mass - well, yes, it is quite large, and the sword is still with a chopping balance.

There is an opinion that a straight version of the Japanese sword would be better than the traditional curved ones. I don't share this opinion. The argumentation of the defenders of this opinion did not take into account the main advantage of the bend - enhancing the chopping ability of the blade. More precisely, she took it into account, but guided by incorrect premises. Even a slight bend of the sword already helps to deliver slashing blows with greater ease, and for a specialized slashing sword, which is the katana, this is what is needed. At the same time, there is no particular loss of capabilities inherent in straight swords with such a slight bend. The only thing missing is a double-edged sharpening, but with it it wouldn’t be a katana. Although, by the way, some nihonto have a one-and-a-half sharpening, that is, the back on the first third of the blade is brought together into a cutting edge and sharpened - like late European sabers. Why this didn’t become a standard, I don’t know.

Hilt

The Japanese sword has a very poor guard. Fanatics begin to shout “but the technique of work does not imply protection with a guard, you need to parry blows with a blade” - well, yes, of course it does not imply. Likewise, the absence of a bulletproof vest does not imply readiness to take a bullet in the stomach. The technique is like this because there is no normal guard.

If you take a katana and instead of the traditional approximately oval tsuba, screw on a kind of “tsuba” with protrusions-kiyons, then it will turn out better, it’s been tested.

Most swords have much better guards than Japanese ones. The crosspiece protects the hand more reliably than the tsuba. I’m generally silent about the bow, twisted hilt, cup or basket. The developed hilt objectively has no significant shortcomings.

You can name a couple of far-fetched ones. For example, the price - yes, of course, a developed hilt is more expensive than a primitive one, but compared to the cost of the blade itself, it’s pennies. You can also say something about changing the balance - but this will not harm most Japanese swords, it will only make fencing easier with them. The words that a developed hilt will interfere with the performance of some techniques are nonsense. If such techniques exist, they can still be performed with a cross. In addition, the lack of a developed hilt prevents the execution of a significantly larger number of techniques.

Why did Japanese swords, with the exception of a short period of imitation of Western-style sabers (kyu-gunto, late 19th and early 20th centuries), never develop a developed hilt?

First, I’ll answer the question with a question: why did developed hilts appear in Europe so late, only in the 16th century? Swords were waved there much longer than in Japan. In short, we didn’t have time to think of it earlier, the corresponding invention simply wasn’t made.

Secondly, traditionalism and conservatism. The Japanese saw European swords, but did not consider it necessary to copy the ideas of these round-eyed barbarians. National pride, symbolism and all that. The correct sword in the Japanese understanding looked like a katana.

Thirdly, nihonto, like most other swords, is an auxiliary, secondary weapon. In battle, the sword was used with powerful gloves. In peacetime, when the katana just appeared from the more ancient tati - see point two. A samurai who had thought of a developed hilt would not have been understood by his fellow classmates. You can figure out the consequences yourself.

It is interesting that after a short era of kyu-gunto, a structurally more advanced weapon than conventional nihonto, the Japanese returned to traditional type swords. Probably the reason for this was the same second point. A country with growing unhealthy nationalism and imperialist ambitions could not afford to abandon such a significant symbol as the traditional shape of the sword. Moreover, in this era, the sword on the battlefield no longer decided anything.

Once again: the Japanese sword has a very bad guard. This fact cannot be objectively objected to.

Design and geometry: conclusion

The Japanese sword has very good characteristics due to its design. It cuts targets well and easily, and is more tolerant of small imperfections in strikes. Chopping balance, martensitic blade and blade curvature are an excellent combination that allows you to achieve very high results with a controlled blow.

Unfortunately, there are also several noticeable flaws in the design of the Japanese sword. Tsuba protects the hand only slightly better than no guard at all. The strength of the blade when deviating from the ideal strike leaves much to be desired. The balance is such that fencing with a Japanese sword is not very convenient.

Conclusion

If we consider a katana to be an exclusively traditionally made Japanese sword, with all these inclusions in the tamahagana, with a martensitic-ferritic blade and tsuba, then the katana is a very old and, frankly speaking, rather defective sword that cannot stand comparison with newer similar sharpened pieces of iron, which can perform all its functions and even more. The katana is a very far from perfect weapon, despite the high cutting properties of its blade.

On the other hand, a sword is like a sword. It cuts well and has sufficient strength. Not ideal, but not complete crap either.

Finally, you can look at the katana from another side. In the form in which it exists - with this small tsuba, with a slight bend, with a jamon visible during traditional polishing, with stingray skin and a competent braid on the handle - it looks very beautiful. Purely aesthetically pleasing to the eye, it doesn’t look too utilitarian. Surely, its popularity is largely due to its appearance. There is no need to be ashamed of this; people generally love all sorts of beautiful things. And the katana - in any form - is truly beautiful.

Forging blades is quite an exciting activity, but where to start?
Unfortunately, in our country there is practically no special literature on this topic. This article is a kind of collection of information from many sources: books on blacksmithing, publications on the Internet, personal experience. Therefore, claims like “I read this somewhere” are not accepted. The article was written for people who do not have the opportunity to sift through all the printed material, but who are very eager to make a knife.

Where to begin? To do this, we must decide what we need the forge for. If from time to time, once every six months, we forge a small blade, then we don’t need a lot of bulky equipment, this is the minimum option. If you decide to devote a lot of time to forging and hope to achieve certain results, it makes sense to gradually acquire professional equipment. You can't save money on this. This is the maximum option.

The forge can be built from any type of building material: intertwined rods coated with clay, logs, various types of stone and brick, cinder blocks, concrete, and also welded iron. Previously, there were forges in dugouts and caves. The roofs were made as single-pitched, double- and hipped and covered with turf, straw, shingles, boards, tiles, roofing felt, slate and iron. But it is better, of course, to choose fire-resistant material for construction: brick, stone, and cover the roof with iron, slate or tiles. The sizes of forges can vary from 2X1.5 to 10X5 m or more, and in height from 2 to 4 m.

If it is possible to build a small forge at your dacha, then this is, of course, very good - it will serve you for many years. But if this is not possible, then do not despair, you can get by with a simple shed or organize a blacksmithing site in the open air. The site for the forge is chosen to be larger - at least 12-15 m2. The vegetation on it is removed and the soil is compacted well. Later, after installing the equipment, you can install a clay floor or concrete it. It is better to make a canopy against a blank wall of the house. To do this, you need to install two (or four) pillars, and put a sloping roof on them. To build a forge, you can use commercially available building materials. The supporting pillars on which the floor beams will be laid must be made of non-combustible materials - asbestos-cement or steel pipes, as well as brickwork. Their height is at least 2.6 m. The side walls are made of flat or corrugated asbestos cement sheets. They are whitened from the inside. An exhaust hood is installed over the forge. In summer it is not hot in such a room, since ventilation occurs due to natural air circulation through cracks and gaps in the structure and the exhaust hood, and in winter it is warmed up by the heat generated by the furnace. However, welding work must be carried out outdoors.
It is advisable to locate the premises for an amateur forge away from residential buildings. If this is not possible, the workshop can be organized in two areas: the metalworking workshop can be placed in the residential part of the house or barn, and the “hot” workshop can be located under a canopy at some distance. In this case, a ventilation device is not required and fire safety is better ensured.

When setting up and equipping a locksmith workshop, it is necessary to be guided by the requirements of the greatest convenience, taking into account material capabilities. A workshop area of ​​at least 10 m2 must be dry and bright. In the absence of natural light, provide good lighting with fluorescent lamps, and in the working area - local lighting with incandescent lamps. The main equipment of a metalworking workshop is a metalworking workbench measuring 60-70X120-150X X 80-85 cm with a vice and drawers for storing tools, an electric sharpener with a set of interchangeable wheels, an electric drill, an electric welding machine, and a set of metalworking tools.
The basic equipment of a forge consists of a forge, an anvil, a forge vice, a water container and a straightening plate. A slab measuring 50X50 cm is made from sheet steel with a thickness of at least 25 mm. Install it on a shoe welded from a corner, preferably one of the angles is 90°. The water container is dug into the ground - this way it will cool faster.

Heating devices.
To heat the metal to forging temperature, we need a heating device. In the classic version, it is a blacksmith's forge.

The basis of a stationary furnace is a pedestal (bed, bed, table), which serves to place the hearth and heated workpieces. Typically, the forge pedestal is installed in the center of the back (main) wall of the forge from the entrance. The height of the pedestal is determined by the height of the blacksmith based on the convenience of transferring the workpiece from the forge to the anvil and back and is taken equal to 700-800 mm, and the area of ​​the horizontal surface of the “table” is usually equal to 1X1.5 or 1.5x2 m. The forge pedestal can be made of brick, sawn stone or reinforced concrete, in the form of a box, the walls of which are made of logs, boards, bricks or stone, and the inside is filled with broken small stone, sand, clay and burnt earth. The upper horizontal part of the table is leveled and, if possible, lined with refractory bricks.
The pedestal can also be made cast (Fig. 46), welded or prefabricated, and the surface of the table can be laid out with refractory bricks and edged with a metal corner.
The central place of the table is occupied by the hearth, or forge nest, which can be placed either in the center or at the back or side wall of the forge.
The hearth is the place where the highest temperature develops, so its walls are usually lined with refractory bricks and coated with refractory clay. The dimensions of the nest are determined by the purpose of the forge and the size of the heated workpieces. The central nest usually has a round or square shape in plan, 200x200 or 400x400 in size and 100-150 mm in depth. To create flames of various types, several grates with various shapes of holes for air passage should be used. Evenly spaced round holes (Fig. 47, b) contribute to the formation of a torch flame, slotted holes (Fig. 47, c, d) - narrow and elongated. An umbrella is installed above the stationary furnace to collect and remove smoke and gases from the forge, which can have different designs. The dimensions of the lower inlet of the umbrella are usually equal to the dimensions of the forge table. The building wall is used as the back wall of the umbrella. Umbrellas are usually made from sheet iron with a thickness of 0.5-1.5 mm.
To better capture smoke and gases, umbrellas are installed above the furnace at a height of H = 400-^800 mm (see Fig. 46), and the exact height is already determined on site depending on the individual characteristics of the furnace - the blast force, the height and dimensions of the exhaust pipe and other parameters. In some cases, umbrellas are equipped with lowering wings. The disadvantage of metal umbrellas is that they burn out quite quickly, and their repair is complicated and time-consuming.
Umbrellas made of refractory bricks are more reliable and durable (Fig. 48). However, brick umbrellas are much heavier than metal ones and to support them they require a rigidly embedded metal frame made of corners or channels, and sometimes additional supports in the corners. Despite the widespread use of open forges in forging, their efficiency (the ratio of the amount of heat required to heat the workpiece to the total amount of heat obtained as a result of fuel combustion) is very low and amounts to 2-5%. It has been established that to heat 1 kg of metal to forging temperature, 1 kg of coal is required. In addition, as a result of direct contact of the metal with coal, the gray surface of the heated metal is saturated, which worsens the mechanical properties of forged products. Therefore, blacksmiths begin to put blanks into the forge when the coal flares up well and the sulfur burns out. To increase the efficiency of an open forge, blacksmiths, using the ability of coal to sinter under the influence of high temperature, arrange a dome-shaped “cap” of sintered coal over the hearth, into which they place the workpieces. As a result, the workpieces heat up faster and oxidize less.
In addition to the “hat,” blacksmiths usually make a stove of several bricks over the hearth.
Unfortunately, conditions often do not allow the installation of a stationary forge, but we can make a portable one. Portable furnaces are all-metal welded or prefabricated structures used for heating small workpieces and blades. A portable forge can be small in size and made from scrap materials.

Fuel.
To heat workpieces, blacksmiths use various types of fuel: solid, liquid and gaseous. Solid fuels are most widely used in small forges - firewood, peat, coal and coke.
Charcoal was the main type of fuel until the middle of the 18th century, and at present it is produced so little that it is practically not used for heating workpieces. However, if moderate heating of small workpieces is necessary, then it is best to do this on charcoal, which should be well burned, dense, hard, not burn too quickly, and have a shiny fracture and “ringing”. The mass of 1 m3 of good charcoal in loose filling is equal to: oak and beech - 330 kg, birch - 215 kg, pine - 200 kg, spruce - 130 kg.
Coke It is most widely used in forge shops for heating workpieces, as it has a relatively low percentage of sulfur and phosphorus content and a high calorific value.
Coal used when it is necessary to heat workpieces to a high temperature. Good quality coal should produce a short flame when burned and sinter well. The density of coal is 1.3 t/m3, and the mass of 1 m3 in loose filling is 750-800 kg. The coal should be black with a sheen the size of a walnut. Blacksmiths call this type of coal “nut”.
Liquid fuel - this is oil, its distillation products (gasoline, kerosene, etc.) and residual oils. The most widely used fuel oils in blacksmithing are fuel oils, which are relatively cheap and have a high calorific value.
Gaseous fuel (natural gas) is increasingly being used in forges, as it is relatively cheap, has a high calorific value, easily mixes with air, burns completely and, most importantly, it does not contain toxic carbon monoxide.
For those blacksmiths and blacksmithing enthusiasts who do not have the opportunity to use liquid or gaseous fuel to heat workpieces, or buy coal or coke, we will consider methods for producing charcoal.
Preparation of charcoal “Heaps” (Fig. 42) are arranged in the forest as close as possible to the place where trees are felled, in an area protected from the wind and not far from water. First, level the area, clear it of turf and compact the soil. Then three stakes are driven in the middle and pushed apart with planks, resulting in a vertical pipe. A mound of highly flammable materials (shavings, dry twigs, birch bark) is poured on the ground around the pipe, logs 1-1.5 m high are placed on the second one. A second one is installed above this row, and on top - horizontal logs and branches form the so-called “cap” . Then the whole heap is covered with a layer of leaves, moss and turf and covered with sand and earth with coal debris on top. In this case, it is necessary to ensure that the tire does not reach the ground. Next, dry branches are placed at the base of the heap on the windward side and set on fire. When the bottom of the logs flares up, the base of the pile is tightly covered and combustion continues with very little air access. It is always necessary to monitor the serviceability of the tire. The combustion process lasts 15-20 hours and is considered complete when blue smoke appears from the vents. After this, all vents are closed and the pile is cooled for several hours. Then they disassemble the tire and break up large pieces. It should be borne in mind that the volume of charcoal is 2 times less than the firewood, and by weight - 4 times. You can arrange “heaps” as shown in Fig. 43. On a flat, wind-protected area, lay two logs 1 m long and 12-15 cm thick in parallel at a distance of 30-40 cm from each other and fill the space between them with dry shavings and wood chips (a). Then they make out a “pile” (b, c). Gradually the “heap” takes the shape of a hemisphere (d). Then the firewood is covered on all sides with wet straw and covered with a layer of earth and covered with turf 10 cm thick, leaving an unfilled belt 20 cm high at the bottom. After this, the window between the lower parallel logs is cleared and the shavings are set on fire. As soon as the wood burns, the window is tightly closed with straw and covered with earth. If somewhere during the combustion process a flame begins to break through, then it is necessary to cover this place with straw and cover it with earth. After 10-12 hours, the firewood burns and the whole pile is covered to the base with a thin layer of earth so that further combustion occurs without access to air. After 3-4 hours, the coal is ready. The pile is raked, the coal is watered to stop burning and collected. An easier way to produce charcoal "in trenches". Logs are placed tightly in a trench 1.5-2 m long and approximately 0.5 m deep. Below, under the logs, you need to lay out small chips and shavings. Then the trench is covered with iron sheets, sand and earth are poured on top. On one side of the trench there is a window through which the wood chips are set on fire, and on the other there is a window for the smoke to escape. After the firewood has ignited, close the windows and combustion continues without air access. It should be borne in mind that it is better to use charcoal made from oak, maple, beech, and birch to heat the workpieces.

Light up the forge as follows. A thin layer of coal is poured into the furnace on a hearth board, and a layer of shavings and small wood chips moistened with kerosene is placed on top. Some dry firewood is placed on top. Another layer of coal is poured onto the burning wood and blowing begins. As soon as the coal is red hot, you can begin heating the workpieces. Periodically, the coal is sprinkled with water to form a crust on top, which retains the high temperature inside the burning mass. Ash from burnt wood and coal spills into the tuyere. The tuyere is periodically cleaned of ash. To do this, the bottom of the tuyere is equipped with a so-called bottom cover.

Blower devices. Hot forging of metals and alloys became possible only when reliable blowing devices appeared. The first such “devices” were slaves who blew into the fire through reed or wooden pipes. Over time, people began to use the skin (fur) of an animal - a goat or a ram - to supply air to the fire, removed with a “stocking”, i.e. entirely. All holes, except two, in the skin were sealed; a clay tube - a nozzle - was inserted into one hole, and the other hole served to suck air into the skin. The man lifted part of the skin by the edge of the hole and air entered the skin. After that, he closed the hole with his palm and, pressing on the skin, released air into the fire. This is how the first blowing devices appeared - bellows, which, with various changes, existed until the 20th century. Nowadays, good "blower" slaves are expensive, but we can use a vacuum cleaner, compressor or electric fan for these purposes.

You can also use a blowtorch to heat the workpieces.

It is installed in a pre-prepared hole, and a small stove made of refractory bricks is placed next to it. You can build a structure in which the blowtorch will be located under the furnace, giving the blacksmith more freedom to move. To do this, the bricks are placed on their ends, a grate is laid on them, and four bricks are installed on it in the form of a furnace. Coal is poured into this recess. The blowtorch is placed under the grate using a pipe. In this case, the blanks are placed in the gap between the bricks.

FORGING TOOLS AND ACCESSORIES

The main supporting forging tool is anvil weighing 100-150 kg, made of carbon steel. Anvils are divided into hornless, one-horned and two-horned. The most convenient is the two-horned one.

The upper surface of the anvil is called the clypeus, or face, and the lower surface is called the base. The top and casing must be hardened and ground, free from cracks and dents. Otherwise, marks may remain on the hot workpiece. On the front surface of the anvil there is a square through hole, usually 30x30 mm in size, for installing tools and accessories. The pointed part of the anvil (horn) is used for bending and straightening rings, and the opposite flat part (tail) is used for bending at right angles.
In addition, anvils can also be used for indirect purposes.

There are several ways to attach anvils.

The traditional method is to mount it on a wooden block - a chair. For this, blanks with a diameter of 500-600 mm of hard wood are used - oak, birch, etc. The height of the chair together with the anvil is about 75 cm, i.e. the face of the anvil should be at the level of the thumb of the blacksmith's lowered hand. If it is not possible to purchase a solid deck, then the chair can be made from separate bars fastened with steel hoops.
If you cannot purchase a real anvil, you can use any suitable steel blank with a flat surface, a piece of rail or I-beam.

Blacksmiths work with hot metal. When processing, the hot workpiece must be held in a certain position. If one hand is enough to work with any tool, the workpiece can be held with the other hand using pliers. In order for the pliers to tightly fit products of various configurations, their jaws are given different shapes. For example, it is more convenient to hold a cylindrical workpiece using pliers with jaws in the form of half rings.

According to the shape of the sponges, pliers are divided into longitudinal, transverse, longitudinal-transverse and special. If the size of the pliers' jaws turns out to be slightly larger than the size of the workpiece, this trick is used. The jaws of the pliers are heated in a forge, they grab the workpiece and press the jaws into the shape of the workpiece with blows of the handbrake. Blacksmith pliers should be lightweight, with long, springy handles. To securely hold the workpieces during work, craftsmen tighten the handles of the pliers with a special clamping ring (spread). As a rule, it is impossible to purchase real pliers, but you can make one yourself; a blacksmith begins by making his own pliers; this work is not easy, but after using pliers, forging a knife will seem like child's play.

To work with the tool, both hands of the blacksmith must be free, so a chair vice is used to clamp hot workpieces.

Such a vice is secured with massive bolts or screws to the main support of the bench. A mechanic's workbench is necessary in any forge, since in order to bring a forged product to its finished form, you often have to work on it with a metalworking tool. It is most convenient to position the vice so that the distance between the floor and the upper level of the jaws is 90-100 cm.
TO percussion instrument include hammers - handbrake hammers, war hammers and sledgehammers. The handbrake is the main tool of a blacksmith, with which he forges small products. Blacksmiths working without assistants (hammers) were called “one-armed” and, in this case, forged “with one hand.” Typically handbrake handles weigh 0.5-2 kg, but blacksmiths often use heavier handbrake handles weighing up to 4-5 kg. Handbrake handles have a variety of head shapes. Thus, to control the forging process when working with hammers, blacksmiths use handbrake handles with a light head, the back of which has a spherical shape. To forge products, blacksmiths use handbrake handles with a heavy head and a wedge-shaped longitudinal or transverse back. This shape of the handbrake head is more universal, since in addition to working with the striker, blacksmiths also work with the rear - accelerating the metal. Handbrake heads are made by forging from carbon and alloy steels (steels 45, 50, 40X), the working surfaces (break and back) are heat treated to a hardness of 48-52. The handles are made of thin-layer wood (hornbeam, maple, dogwood, birch, rowan, ash) with a length of 350-600 mm. The handles should be smooth, without cracks, and fit comfortably in the hand. War hammers are heavy two-handed hammers weighing 10-12 kg. War hammer heads come in three types: with a one-sided wedge-shaped back, with a double-sided longitudinal or transverse back.

The lower working surface of the head - the strike - is intended for the main forging, and the upper wedge-shaped back is for accelerating the metal along or across the axis of the workpiece. The material of the hammer head is steel 45, 50, 40X, U7, the hardness of the head and back is 48-52 to a depth of 20-30 mm. The hammer handle is made from the same types of wood as the handbrake, and the length of the handle is selected depending on the weight of the hammer head and the height of the hammer and is equal to 70-95 cm. A blacksmith working with one or two hammers is called “two-handed” or "three-handed". Working with hammers in three hands is carried out during complex forging of large products. A sledgehammer is a heavy (up to 16 kg) hammer with flat strikers, used for heavy forging work, where a large impact force is required. All impact tools must be as reliable as possible, When working, special attention is paid to fastening the handle with the head. The shape of the hole in the head of the hammer - “planting”, where the handle is inserted, must be elliptical and have a slope of 1: 10 from the middle to the side edges. This makes it easier to insert the handle and ensures its reliable fastening after driving Practice has established that the most reliable metal “jabbed” wedges are those that enter to a depth equal to 2/3 of the width of the hammer head, and the wedge should be driven in obliquely to the vertical axis, which allows the wood to be pushed apart in 2 planes.
When working with war hammers, three types of blows are used: light, or elbow (a), medium, or shoulder (shoulder strike) (b), strong, or hinged, when the hammer describes a full circle in the air (c).

Hammers use mounted blows when forging large masses of metal and during forge welding of massive parts.

Blade forging.

Forging steel is the initial stage of the heat treatment process, in which no less attention than forging should be paid to the operating temperature of the blank. Particular attention should be paid to not falling below the temperature limit, when internal stresses begin to develop in the steel due to overcooling. There is a technique that the Japanese call “wet forging”. It involves moistening the surface of the anvil and hammer with water during forging. In this case, the water does not cool the workpiece, but promotes the separation of scale from the surface, preventing it from “driving” into the blade. Unlike hot steel, scale is not malleable and leaves marks (“craters”) on the surface.
It is more convenient to start forging by forming the shank. But first you need to get a preliminary blank; if you have a rod, then convert it into a rectangle (square), and then cut it into a strip of the required thickness with an allowance for machining. It is convenient to align and check the blade before placing it in the forge for heating again, so as not to waste time on this after removing it from the forge. Particular attention should be paid to the positioning of the workpiece - it should be positioned strictly parallel to the plane of the anvil. The hammer head must act on the surface with its entire plane: otherwise, unevenly deformed areas are formed in the blade, which are subsequently strengthened (with the formation of internal inhomogeneities). Next, taking the strip blank, retreat the required distance

and perform a “break”, blows are applied to the edge on both sides of the workpiece to obtain a stepwise transition from the body of the blade to the shank.

This can be done either with the sharp toe of a hammer or using a backing tool. Then you pull the part separated for the shank onto a cone.

That's it, the shank is ready and now you can handle it with pliers, and later modify it with an electric sharpener.
Now we begin to form the body of the blade itself. To do this, you first need to shape the tip; this can be done either by forging or by simply cutting off the excess with a chisel.

By rounding the sharp corners and aligning the lines, we get a finished contour blank of the blade.
In principle, you can stop there and form the slopes using sandpaper. But you can go further and pull back the edge and decorate the slopes with forging. Here you need to take into account the expansion of the metal and take the width of the initial workpiece less than what you plan to get on the finished knife. A common mistake when forming a sharpening plane is lifting the workpiece above the anvil. This plane must be forged on a workpiece lying on an anvil - the side opposite to forging remains flat while you form the sharpening plane with a hammer.

It is useful to start work by profiling the “inconvenient” side, and once completed, turn the workpiece over to the other side. It is very important to forge both sides of the blade evenly. Otherwise, due to the uneven structure, the blade will “lead” or an asymmetrical profile will be formed. Another common problem is workpiece buckling. The old adage about not hitting the blade is wrong. You can hit the blade, but this requires a special technique. To do this, use the full length of the anvil, place the curved section on it and remove the curvature with light blows. If the blade has already been formed, the blows are applied with a mallet on a wooden block - the blade and butt are not damaged. After all the difficulties and failures, you have received a blade blank that vaguely resembles the knife of your dreams; the less grinding work required in the future, the better.

After forging and grinding, a contour and bevels must be formed, but the thickness of the cutting edge itself must be at least 1 mm, in order to avoid its “wave” during hardening; the overall symmetry of all parts is also an important point and affects possible hardening deformations . A forged blade has a large number of internal stresses, which during hardening can lead to its bending. To reduce this, the blade should be annealed before hardening. Place the blade with the butt down in the forge, heat the blade until red with low blowing, then turn off the blowing, leave the blade to cool with the forge overnight, and then go and rest.
The next stage of knife manufacturing will be heat treatment of the blade, let’s look at it in more detail.

Types and modes of heat treatment of steels.

Depending on the chemical composition of the steels, the dimensions of the forgings and the requirements for finished parts, the following types of heat treatment of steels can be used in forges.
Annealing consists of heating steel to a certain temperature, holding it and then very slowly cooling it, most often in conjunction with a forge or furnace.
Heating of steel for annealing is carried out in a forge or furnace. In order to prevent carbon from burning out from the surface of the steel when heated in a forge, the forgings are placed in metal boxes, sprinkled with dry sand, charcoal or metal shavings and heated to the temperature required for annealing the given grade of steel. The heating duration is taken depending on the size of the forgings, approximately 45 minutes for every 25 mm of the greatest cross-sectional thickness. Heating above the annealing temperature and prolonged exposure at this temperature are unacceptable, since the formation of a coarse-grained structure is possible, which will sharply reduce the impact strength of the metal. Cooling of forgings can be carried out somewhat faster than with a forge and furnace if you use the following recommendations. High-quality carbon structural steels should be cooled to approximately 600 °C in air to obtain a fine-grained structure, and then, to avoid internal stresses, cooling should be carried out slowly in a furnace or in a box of sand or ash installed in a forge. Tool carbon steels should be cooled in a furnace or forge to 670 °C, and then the cooling rate can be accelerated by opening the furnace dampers and removing fuel from the forge.
Depending on the purpose of changing structural transformations (the state diagram is shown in Fig.)

The following types of annealing are used.
Forgings made of carbon steels are cooled at a rate of 50... 150 degrees/h, and those of alloy steels - 20... 60 degrees/h. As a result, internal stresses in the metal are relieved, it becomes softer and more ductile, but less hard. Low annealing consists of heating forgings to a temperature slightly above the critical 723 °C (up to approximately 740...780 °C), with periodic temperature changes below and above point 5 and slow cooling to 670 °C, after which cooling can be accelerated. Such annealing is used to reduce hardness, increase ductility and improve machinability of forgings made of tool steels. Recrystallization annealing consists of heating steels to a temperature of 650...700 °C and cooling in air. With the help of this annealing, work hardening is removed and the structure of steels damaged during forging at low temperatures is corrected. Normalization annealing (normalization) consists of heating forgings to a temperature of 780... ...950°C, holding it for a short time and then cooling in air. Normalization, as a rule, is used to eliminate the coarse-grained structure formed as a result of a forced or accidental increase in the time the workpieces are in the furnace to correct the structure of overheated steel (overheating), refine the grain, soften the steel before cutting and obtain a cleaner surface when cutting, as well as general improvement of the structure before hardening. As a result of normalization, the steel turns out to be somewhat harder and less ductile than after low annealing. Normalization, compared to annealing, is a more economical operation, since it does not require cooling along with a forge or furnace.
Hardening is used to increase the hardness, strength and wear resistance of parts obtained from forgings. Heating of steel for hardening is carried out in forges or heating furnaces. The parts are placed in the forges so that the cold blast of air does not fall directly on the steel. You need to ensure that heating occurs evenly. The more carbon and alloying elements the steel contains, the more massive the part and the more complex its shape, the slower the heating rate for hardening should be. The duration of exposure at the quenching temperature is approximately assumed to be equal to 0.2 of the heating time. Excessive holding at the quenching temperature is not recommended, as this causes grains to grow rapidly and the steel loses strength.
Cooling is an extremely important hardening operation, since obtaining the required structure in the metal practically depends on it. For high-quality hardening, it is necessary that during the cooling process of the part, the temperature of the liquid remains almost unchanged, for which the mass of the liquid must be 30-50 times greater than the mass of the part being hardened. To achieve uniform hardening, the heated part must be quickly immersed in the coolant and mixed in the liquid until completely cooled. If only the end or part of the product is hardened (for example, an ax blade), then it is lowered into the quenching liquid to the required depth and moved up and down so that there is no sharp boundary of the cooling rate between the hardened and non-hardened parts of the product and cracks do not appear in the transition part. The blades are immersed either strictly vertically or at an angle with the blade part down.
The choice of cooling medium depends on the grade of steel, the cross-sectional size of the part and the required properties that the steel should obtain after hardening. Steels with a carbon content of 0.3 to 0.6% are usually cooled in water, while those with a higher carbon content are cooled in oil. In this case, the configuration of the parts and their cross-section should be taken into account. When hardening steel, it is difficult to obtain the desired two-speed cooling. In the temperature range 650...450 °C, rapid cooling is required at a rate of 20...30 °C/s. This avoids warping and cracking.
It is clear that the best quenching medium would be a two-layer liquid, in which the top layer is water with a temperature of 18...28 ° C, and the bottom layer is machine oil. But, unfortunately, such a two-layer liquid cannot be obtained, because the oil floats to the surface. With a certain skill, you can use the following cooling mode. Submerge the part in water for a few seconds and then quickly transfer it to the oil. The approximate cooling time in water before transfer to oil is 1...1.5 s for every 5...6 mm of the part section. This method of cooling is called “through water into oil” or intermittent quenching. It is used for hardening carbon steel tools.
With a large cross-section of the part, the outer layers cool faster than the inner ones, and therefore the hardness on the surface is greater than in the middle. Carbon steels, for example steels 40 and 45, are hardened to a depth of 4...5 mm, and deeper will be a partially hardened zone and an unhardened core. Alloying elements - manganese, chromium, nickel, etc. contribute to deeper hardening. Some blades require a lot of surface strength while maintaining a soft, tough core. It is recommended to surface harden such blades. One of the simplest methods of such hardening consists of loading the part into a high-temperature furnace (950...1000 °C), quickly heating the surface to the hardening temperature and cooling at high speed in a flow-through cooling medium. Often, quenching is performed immediately after forging without additional heating, if the temperature of the forging after forging is not lower than the quenching temperature.
Hardening can be strong, moderate and weak. To obtain strong hardening, water at 15...20 °C is used as a cooling medium before immersing the part in it and aqueous solutions of table salt and soda (sodium carbonate). Moderate hardening is obtained by using water with a layer of oil 20...40 mm thick, oil, fuel oil, soapy water, liquid mineral oil, and hot water. Weak hardening is obtained if a stream of air or molten lead and its alloys is used as a cooling medium.
Hardening requires attention and skill. Poor hardening can ruin almost finished parts, i.e., lead to the formation of cracks, overheating and decarburization of the surface, as well as to grooves (warping), which largely depends on the method and speed of immersion of the part in the coolant.
Hardening is not the final heat treatment operation, since after it the steel becomes not only strong and hard, but also very brittle, and large quenching stresses arise in the forging. These stresses reach such values ​​at which cracks appear in the forgings or parts from these forgings are destroyed at the very beginning of their operation. For example, a freshly hardened blacksmith's hammer cannot be used because when it hits metal, pieces of metal will break off. Therefore, to reduce brittleness, internal quenching stresses and obtain the required strength properties of steel after hardening, forgings are tempered.
Tempering consists of heating hardened steel to a certain temperature, holding it at this temperature for some time and cooling it quickly or slowly, usually in air. During the tempering process, no structural changes occur in the metal, but quenching stresses, hardness and strength decrease, and ductility and toughness increase. Depending on the grade of steel and the requirements for hardness, strength and ductility of the part, the following types of tempering are used.
High tempering consists of heating the hardened part to a temperature of 450...650 °C, holding at this temperature and cooling. Carbon steels are cooled in air, and chromium, manganese, chromium-silicon steels are cooled in water, since their slow cooling leads to temper brittleness. With this tempering, quenching stresses are almost completely eliminated, ductility and toughness increase, although the hardness and strength of the steel noticeably decreases. Hardening with high tempering, compared to annealing, creates the best ratio between the strength of steel and its toughness. This combination of heat treatment is called improvement.
The average tempering consists of heating the hardened part to a temperature of 300...450 °C, holding at this temperature and cooling in air. With this tempering, the viscosity of the steel increases and the internal stresses in it are relieved while maintaining a sufficiently high hardness. Low tempering consists of heating the hardened part to a temperature of 140...250 °C and cooling at any speed. With this tempering, the hardness and toughness of the steel almost does not decrease, but the internal quenching stresses are relieved. After such a tempering, the parts cannot be loaded with dynamic loads. Most often it is used for processing cutting tools made of carbon and alloy steels.
When making hand-forged metalworking, blacksmithing or measuring tools, blacksmiths often use hardening and tempering with one heating. This operation is called self-tempering and is performed as follows. The forging heated for quenching is cooled in water or oil not completely, but to a temperature slightly higher than the tempering temperature, which can be determined when removing the forging from the quenching medium, by the color of the tarnish on the surface of the forging pre-treated on an emery wheel. After this, the forging is finally cooled by immersing it in water or oil.
In the absence of measuring instruments, the heating temperature of the forging is determined by the color of the tarnish. To do this, before heating the forging for tempering, in the right place, clean a small area with sandpaper or other abrasive. Heat the forging and observe the change in color of the metal along the cleaned surface. In this case, the tarnish colors will correspond to the following approximate heating temperatures of the forging:
Temperature, °C
Grey_____________330
Light blue_______314
Cornflower_______295
Purple________285
Purple-red___275
Brown-red__265
Brown-yellow___255
Dark yellow_______240
Light yellow______220
Below are recommended tempering temperatures for some tools and parts (in degrees Celsius):
Cutters, drills, taps made of carbon steel. . . 180-200
Hammers, stamps, taps, dies, small drills. . 200-225
Punchers, scribers, drills for mild steel. . 225-250
Drills and taps for copper and aluminum, chisels for steel and cast iron. 250-280
Tool for wood processing. . . . . . . 280-300
Springs. . . . . . . . . . . . . . . . . 315-330
At higher temperatures, the surface of the steel darkens and remains so until a temperature of 600 ° C, when incandescent colors appear. Heat treatment regimes for steels must be observed very strictly, since only correct heat treatment makes it possible to obtain blades with a given strength, wear resistance, workability, ductility, etc.
After heat treatment, it’s time for final mechanical processing; it can be carried out using a simple device

or use an electric sharpener, but this is a topic for another discussion.

FORG WELDING.

The operation of obtaining a permanent connection by hand or machine forging is called forge welding. This method refers to pressure welding and consists in bringing the surfaces to be joined together by plastic deformation over distances (2-M) -10"8 cm, at which interatomic attractive forces arise. A high-quality permanent connection can only be obtained if oxidized and other oxidized substances are removed from the surfaces being joined. contaminating films. When pressure welding, this is achieved by applying pressure to the welded surfaces sufficient to destroy and remove contaminating films and remove all irregularities on the surfaces of the workpieces. Thus, to carry out forge welding, the metal of the workpiece must have high ductility, low resistance to deformation, and the surfaces being joined must be thoroughly cleaned at the time of plastic deformation.
Forge welding does not provide high reliability of the welded joint, it is low-productive, suitable for a limited number of alloys, requires highly qualified workers and is less often used in factories, where there are always other, more modern welding methods (arc, gas, contact, etc.) -However, in field conditions, when repairing non-critical machine parts, and when forging complex forgings by hand forging, forge welding is often used.
Obtaining a permanent joint by forge welding consists of the following main operations: preparing workpieces for welding, heating the parts of workpieces to be welded, welding workpieces by plastic deformation, finishing the workpiece at the welding site and straightening.
Information about alloys subjected to forge welding. Low-carbon structural steels are most often subjected to forge welding. For forge welding, steels with a carbon content of up to 0.3%, no more than 0.2% silicon, 0.6-0.8% manganese and no more than 0.05% each of sulfur and phosphorus are recommended. If it is necessary to weld steels with a high carbon content (more than 0.3%), it is recommended to add mild steel sawdust, which contains very little carbon, to the welding flux. When processing a part of a workpiece heated for welding with such sawdust, the metal is decarbonized, which increases the weldability of the surface layer of the workpiece.
Preparing workpieces for welding consists of giving the ends to be joined a certain shape. The prepared ends are usually upset and their shape depends on the welding method. Increasing the cross-section of the welded ends is necessary to perform plastic deformation during welding and give the welded part of the forging the required shape.
Heating mode of workpieces for welding. The heating temperature of steels for welding depends on the carbon content in them. The more carbon in steel, the lower the heating temperature. Mild low-carbon steel is heated to a temperature of 1350-1370^0. At this temperature, the welded ends become dazzling white. When welding steel with a high carbon content (for example, when welding an ax blade made of U7 steel), the workpiece is heated to a temperature of 1150 ° C. The workpiece at this temperature has a white heat color with a yellowish tint. Good welding quality is possible when performing plastic deformation without lowering the temperature of the metal. Therefore, welding should be carried out quickly, the welded ends should be thoroughly cleaned of scale and slag.
The heating temperature of workpieces for welding exceeds the forging start temperature Tn. As is known, at temperatures above Tn not only intensive scale formation occurs, but also metal burnout is possible. To reduce the formation of scale and remove it from the surface before welding, as well as to protect the metal from burning, the workpiece is sprinkled with flux. Quartz sand mixed with borax or table salt is used as a flux. Since manganese increases the weldability of steel, sometimes a little manganese is added to the flux. Flux is sprinkled onto the workpiece during the heating period, when its temperature reaches 950-1050 ° C. Under the influence of high temperature, the flux combines with scale, forming slag, which envelops the workpiece and protects its surface from oxidation during further heating.
Forges and welding furnaces are used to heat the welded ends. Chamber furnaces designed for heating workpieces for forging are not applicable in this case, since they do not provide heating to high welding temperatures. Heating for welding requires that the flame in the forge or furnace is not oxidized, that is, that fuel combustion occurs with maximum oxygen absorption and there is no excess of it in the hearth.
The best fuel for the forge when heating workpieces for forge welding is charcoal.
The heated workpieces are removed from the forge, the resulting slag and scale are knocked off by hitting an anvil or hammer blows, or they are cleaned off with a metal brush. Then, quickly putting the ends of the workpieces to be welded together, first apply weak but frequent blows to the welding site. With weak impacts, the remaining slag is squeezed out, the joint surfaces are pressed tightly against each other, which protects them from oxidation. The welding is completed with strong blows, subjecting the welding site to sufficiently large deformations and giving the workpiece the desired final shape.

When forging the joint, the individual layers of metal of the joined ends are embedded into each other and intertwined, which further increases the strength of the joint. Depending on the final shape of the weld, the forging is straightened using smoothers, crimps, tampers and other forging tools.
Welding methods. The ends of the parts to be welded are prepared and welded in different ways.
Welding an overlap joint provides the greatest strength to the welded joint. The increased quality of the welded joint is explained by the increased contact surface of the welded parts and the ability to subject the joined area to large deformations. Before welding, the ends of the workpieces are planted and they are shaped into curved thickenings (Fig. 88, a), rotated relative to the longitudinal axis at an angle of ~30°.
The prepared ends, preheated to 1000° C and coated with flux, are heated to welding temperature. The heated ends, cleared of flux and scale, are placed on top of each other and pressed against each other with light but frequent blows, and then the joint is carefully forged with strong blows. At the same time, a broaching operation is performed to give the welding area its original dimensions. After welding, the forging is given the required shape.
The advantage of this welding method is also that the shape of the initial welded surfaces ensures good removal of slag residues from the surfaces being joined. Workpieces with a thickness or diameter of up to 30 mm are welded in one step and with one heating. When the thickness of the welded ends is more than 30 mm, the operation is carried out in two stages: from the first heating, thin sections of thickenings are welded, from the second heating, the final welding is performed. When the diameter of the workpieces is over 50-60 mm, welding cannot be carried out by hand forging; it is performed with a hammer.
Socket welding requires more complex preparation of the welded ends. One of them is planted, cut along the longitudinal axis of the workpiece, and the resulting “petals” are moved apart. The end of the second workpiece is also planted and sharpened so that it fits into the cut of the first workpiece. The ends, heated to welding temperature and cleared of slag, are inserted into each other and with vigorous blows, forming the metal, welding is carried out, and then the final finishing of the workpiece is performed.
Butt welding is used in cases where, due to the small size of the workpiece, it is impossible to prepare the ends to be joined for an overlap joint. In some cases, the ends of the workpieces are simply rounded, heated to welding temperature, joined to each other and welded with blows along the axis on both sides. Under the influence of impacts, the heated joint settles and increases in diameter. Therefore, after welding, the joint is pulled to the required diameter.
Welding a butt joint without preliminary upsetting of the joined ends is inferior in strength to welding the same joint with preliminary thickening of the ends of the workpiece. With this method, the heated ends are planted and the ends are rounded. The prepared ends are joined and, applying blows along the axis of the workpieces to their cold ends, welding is performed, and then the final finishing of the forging is performed.
Strip blanks are welded by split welding. The ends of the workpieces are cut along the longitudinal axis and separated as shown in the figure. After heating to welding temperature, the ends are joined and forged until a strong connection and original dimensions are obtained.
When welding the ends of ring-type forgings or repairing them, welding using checkers is used (Fig. 88, e). Before heating for welding, the welded ends / and 2 are subjected to upsetting and forging until the shape shown in the figure is obtained. Auxiliary blocks 3 are prepared from the metal of the workpiece. At the welding temperature, blocks 3 are placed between the ends 1 and 2 of the fixed workpieces and subjected to joint plastic deformation with strong impacts. The welded place is then straightened. This welding method is usually performed with a hammer.
Defects in forge welding and control of the welded joint. Defects during forge welding can be conditionally reduced to two types: low quality of the welded joint, discrepancy between the dimensions and shape of the forging required. Welding is considered well done if the strength of the welded joint is not lower than 80-85% of the strength of the metal of the workpieces being welded. The strength of the seam can be checked by bending the rod at the welding site. If the welding quality is good, when bending, the seam does not separate and cracks do not appear on the metal surface.
Violation of forge welding conditions can lead to the following defects.
Lack of penetration occurs when the joining surfaces are poorly cleaned before welding: the joining surfaces are poorly cleaned of scale; after cleaning the surfaces of the heated workpieces, the start of forging was delayed and secondary scale formed on the joined surfaces; the surfaces to be welded were poorly treated with flux; When welding a butt joint, the ends of the workpieces were poorly rounded; slag remained in the middle of the joint, preventing welding of the ends.
Burnout is an irreparable defect that occurs when the ends of the workpieces are heated to a temperature exceeding the welding temperature. This defect is very likely when performing forge welding, since the welding temperature is very close to the burnout temperature and if the heating is not careful enough, it is easy to make a mistake and burn out the metal.
Low strength of the weld and heat-affected zone. Heating of workpieces to welding temperature is accompanied by grain growth. In the case of a small amount of metal when upsetting the welded ends, the degree of deformation of the metal during welding will be insufficient, the grains will not be crushed and the weld metal will have a coarse-grained structure and reduced strength.
Low strength of the heat-affected zone occurs when the ends of the workpiece are heated before long-length welding. The coarse-grained structure of the metal at the joint is processed (crushed) during the forging of the thickenings, and the zones adjacent to the ends and without thickenings are not subject to such deformation and retain the coarse-grained structure. Therefore, when welding, only the thickened ends of the workpieces being joined should be heated.
Inaccuracy in the dimensions of the forging section after welding occurs when there is insufficient metal on the ends being welded. When forging such ends, the cross-section of the forging is reduced and the final dimensions will be less than those required according to the drawing.
Occupational safety rules when performing forge welding are associated with high heating temperatures of the metal and the use of fluxes. When overheated, the metal begins to sparkle, and liquid slag forms on the surface of the workpiece. When working with such workpieces during stripping and forging, splashes of slag and sparks can cause burns, as well as ignition of flammable materials and clothing. Therefore, when forge welding, heating forgings should be carefully and thoroughly cleaned of scale and slag, and the workplace must meet fire safety requirements.
Useful tips.
1. Standard hammers can be used as blanks for making bits, shaped chisels, etc., giving their working ends the required shape.
2. A closed-type furnace can be made from a cast-iron stove, the inner surface of which should preferably be lined with refractory bricks. Air is supplied through a ash pan, into the door of which a piece of steel pipe is mounted.
3. Using a vacuum cleaner to supply air to the forge, it is connected to the network through a laboratory transformer. By changing the supply voltage, the air supply is adjusted. In this case, the vacuum cleaner motor will be protected from overload.
4.Good grates for the furnace are obtained from parts of cast iron grates used in road and sidewalk water intakes.
5. To protect small parts from overheating and falling into the fuel, they are heated in a section of steel or cast iron pipe, which is placed in hot coals.
6. When the surface of the coals is wetted with water, a sintered crust is formed, which retains heat well in the heating zone.
7. You can restore the notch of an old file or needle file by keeping it in a mixture of dilute sulfuric and hydrochloric acids in a 1:1 ratio. In this case, the size of the notch will become slightly smaller.
8. Using blowtorches as a heat source, they are protected from overheating by a screen made of sheet asbestos with a hole for the nozzle, or a metal mesh coated with clay is used for this.
9. To increase the service life of nichrome spirals, they are alliterated, that is, the surface is saturated with aluminum. To do this, the spirals are kept in molten aluminum with the addition of about 1% ammonium chloride at a temperature of 950-1150 °C.

Blacksmith-gunsmith Vasily Ivanov, specializing in traditional Japanese weapons, at the request of the editors of Popular Mechanics, took on the project of historical reconstruction of a 13th-century European sword. The sword had to be made from scratch - starting with smelting steel from ore. The first model was unsuccessful, and only the second successfully passed control tests

To save time, we had to deviate somewhat from historical authenticity and replace the hammering team with one pneumatic hammer. With its help, a multi-package block is given its original shape - it is forged into a strip, the shank of the blade is formed

Although a pneumatic hammer saves effort and time, some operations can only be done manually

Hardening is the most effective part of the heat treatment process of steel alloys, including annealing, hardening and tempering. During hardening, a heated carbon steel workpiece is dipped into a bath of water, saline or oil.

With rapid cooling, martensite appears in steel - a crystalline structure, due to which the metal becomes strong, hard and elastic (although it loses its ductility and becomes brittle). The resulting unevenness of internal stresses is partially removed during subsequent tempering - heating to a low temperature and cooling

To forge the dales, a special tool is used - a shperak. These are T-shaped pliers with round jaws, between which the future blade is clamped

When forging a shperak with a pneumatic hammer, semicircular grooves are formed on both sides of the blade - valleys, which are then polished by hand using wet abrasive stones. The fullers are often mistakenly called “blood holes,” but in fact they serve as stiffening ribs, and at the same time they allow you to reduce the weight of the blade

The last, final stage of making a sword is “dressing” the blade. We cast the crosshair from bronze, and then used a forge to weld two bronze strips together, leaving a hole in the center for the shank of the blade

The pommel (“apple”) is also cast from bronze. A metal ring is inserted under the suede, which is wrapped around the wooden handle of the ball, for better retention and control of the position of the sword. To give a historically authentic look, we heated the bronze parts with a gas torch so that they became patina and did not look new.

In the February issue of PM, we began a story about our project for the historical reconstruction of a medieval sword under the leadership of the famous blacksmith-gunsmith Vasily Ivanov, head of the workshop of traditional Japanese weapons Ishimatsu. In the first article, we described how we obtained the required grades of steel from iron ore, and promised to publish a continuation in the next issue. However, technical difficulties awaited us, which delayed the continuation for almost two months. However, these difficulties are also quite historically authentic - medieval blacksmiths and gunsmiths also encountered them.

From whetstone to blade

So, we have a steel bar assembled from seven packages - each of them has its own structure and purpose in the design of the blade. The first step is to turn this block into the actual workpiece - forge it into a steel strip of given dimensions, taking into account the margin for forging and pulling the blade (to save time, we deviated a little from historical authenticity, using a pneumatic hammer for this operation). At the final stage of this stage, Vasily, by hand, gives the strip its original geometry, forming the shank, tip and heel of the blade. From this moment on, the stripe’s shape already vaguely resembles the future sword. After the metal had cooled, Vasily once again carefully examined and measured the resulting workpiece, leaving a small supply of metal to correct future mistakes.

The next stage is forging the dales. Fullers are longitudinal grooves running along part of the length of the blade. Sometimes they are mistakenly called “blood fillers”, although in fact the function of the fullers in the design of the blade is completely different - they reduce the mass of the blade and play the role of stiffening ribs. The dales are forged using a special tool called a shperak. Shperak is a T-shaped pliers with circular jaws; the workpiece is clamped between them and forged, as a result of which longitudinal grooves appear on both sides of the blade.

And finally, the workpiece takes on a more or less final appearance after the blade is drawn (formed). “This is a rather painstaking process,” explains Vasily. “If at the previous stages you can use a pneumatic hammer, then to draw back the blade you need high precision, which can only be achieved by hand forging.” At this stage, the geometry of the future blade is finally set; you can slightly change the location of the center of gravity by varying the thickness of the blade at the tip or at the base. The thickness of the cutting edge at this stage is 2−2.5 mm. It can’t be thinner: the steel can be overheated, and there won’t be any reserve left for any “maneuvers.”

But the preliminary work is almost finished. Vasily once again checks that the dimensions of the blade comply with our technical specifications, straightens the workpiece and moves on to the next stage - heat treatment.

Heat treatment

Hardening does not begin immediately. First you need to get rid of internal stresses in the material that may have appeared during forging. To do this, the blade is annealed - heated to 950-970°C, and then left to cool slowly right in the forge - this process takes 5-8 hours. Then the workpiece is finally straightened, and minimally, to avoid over-compaction of the material in various parts of the blade.

Tempering is the most well-known part of the heat treatment process. During hardening, the workpiece is rapidly cooled, carbon steel becomes strong, hard and elastic (its ductility and toughness decreases).

Vasily adds charcoal and lights the forge, explaining: “Charcoal burns more evenly. In addition, it is lighter than coke, and therefore there is less chance of damaging a hot plastic blade when heated.” He heats the blade, trying to achieve uniform heating to approximately 890-900°C, then removes the workpiece from the forge and lowers it into a bath of saline solution for 7-8 seconds. Then the blade needs to be released - to remove the internal stresses accumulated in the metal during hardening, to make it less brittle and to increase impact strength: heat it to a low temperature (180-200°C) and cool it to room temperature in water (or air - methods vary). This operation is usually performed several times (in our case three) with breaks of 15-20 minutes. After this, the blade is left alone for several days so that the remaining internal stresses appear and “settle down.” “It is advisable to hang the blade, and not just place it on an anvil,” notes Vasily. “Otherwise, unevenness in heat transfer can disrupt the geometry, that is, the blade will simply ‘lead’.” But even in a suspended state after several days, the blade, as a rule, needs a little gentle cold straightening.

After heat treatment - another quality control. Vasily carefully examines the blade for “lack of penetration”, cracks, checks it for bending and torsion, hits the blade flat on the board and inspects it again. Then he grips the blade with two fingers and hits it with a metal stick, listens carefully to the ringing and shakes his head skeptically: “When the sound is ringing, bell-like, there is a long vibration through the sword - this indicates that the sword is forged, the absence of internal microcracks and a sufficiently high degree of hardening. If the sound is hoarse, dull and short-lived, it means there are some defects. There’s something wrong here: I don’t like the sound.” But there seem to be no objective signs, so we move on to the next stage.

Mechanical restoration

This rather monotonous process takes almost two weeks. During this time, the gunsmith, using wet abrasive sandstone stones, removes excess metal, grinds the valleys, shapes and sharpens the cutting edge. But finally, the work is nearing completion, and Vasily begins the final check - he examines the blade again, cuts several wooden blocks, a soft steel corner, bends the blade several times: “It seems that it was hardened unevenly - when bending, the base forms an arc, and the tip almost straight,” and at that very moment the blade, clamped in a vice, cracks with an unpleasant crunch. Its end is still clamped in a vice, and the rest is in the hands of Vasily, who shrugs: “I told you there’s something wrong here!” That’s why we made several blanks during smelting. It’s okay - we’ll figure out why this happened and try again.”

Broken Sword

Actually, this is what delayed the publication of this article for more than two months - it was necessary to understand the reasons for what happened, conduct several experiments, make adjustments to the process... and repeat the whole path from the multi-package bar again.

Why did our first sword break? “Let me remind you that we used non-standard steels, the exact composition of which is unknown, which means their characteristics are difficult to predict,” says Vasily. — Apparently, the quenching was excessively 'hard' - too high a temperature and the use of a saline solution led to the formation of microcracks in the high-carbon steel. This was felt already at the stage of preliminary testing after quenching - in sound and flexibility, but was finally confirmed only after machining - the steel microcracks are visible on the surface.”

Sounding Blade

After a series of experiments, the heat treatment process was modified. Firstly, we decided to slightly change the geometry of the blade, increasing the thickness of the tip to make the hardening more uniform. Secondly, they reduced the heating temperature to 830-850°C and decided to carry out the hardening itself not in a salt bath, but in a water-oil bath (30 cm thick layer of oil on top of water). After such a two-stage (due to oil having a boiling point of about 200°C) hardening, lasting 7-8 seconds, the blade was cooled in the air (in a cold of -5°C) until completely cooled (5 minutes). The method of further heat treatment was also changed: the blade was released to relieve internal stress in five passes, heated to a temperature of 280-320°C, and then left to cool in air.

And again - a break of several days, straightening, roughing, grinding and sharpening.

And finally, Vasily again hits the blade with a metal stick, listens to the long musical ringing, and a satisfied smile appears on his face: “It seems that this time everything worked out!” He clamps the blade in a vice and pulls on the tang - the blade bends into an almost perfect arc.

All that remains is all sorts of little things - etching the design so that a beautiful pattern appears on the surface of the blade, adjusting the wooden scabbard, installing a suede-covered handle, bronze crosshair and pommel (the so-called apple) on the sword. The sword, almost exactly the same as the one that Russian warriors of the 13th century could fight with, is completely ready - all that remains is to test it. But more about this in one of the following issues.