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SECRET OF MAKING STEEL PRODUCTION

A collection of methods for the manufacture of technology secrets for all occasions

Glossary

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The material of the blade - hardened steel - has the property that hardness and its elasticity, within certain limits, are in inverse relationship. The hardness of the blade should be large enough so that the knife does not quickly become blunt, but not excessive, otherwise the cutting edge crumbles or the blade breaks.

It has long been noted that the durability (durability) of the blade does not always depend on the hardness of the blade. It is not uncommon at which time the soft blade is blunt in labor less than the more cruel. At the Zlatoust plant, the well-known metallurgist Anosov, trying to recover the secrets of the technology of making damask steel, determined the durability of the blade by cutting felt rolls. In the course of the work, it became clear that blade samples taken from one piece of steel, which also underwent the same heat treatment, have different characteristics.

The cutting properties of the blade are determined by the parameters of the micropile, which is formed when it is sharpened, also visible if you look at the edge of the blade under a microscope. The teeth of this saw should be small and the same, their tops should have the maximum hardness also not to be painted. This is ensured by the microstructure of the material also by the method of sharpening the blade. The sharper the sharpening angle, the more easily the blade slips into the material being processed. But since the thin blade is more fragile, in order for it not to break, it is necessary to increase the elasticity, thereby reducing wear resistance.

In ancient times, the optimum combination of these properties provided damask material, which was brought from India. In the countries of the near East, he also came in the form of ingots and then, in the process of forging, also quenched by special methods, acquired unique properties, combining high hardness and greater elasticity as compared to those that did not have similar qualities, in our understanding, ordinary blades. However, Bulat were also different. At the end of the last century, at what time the interest in the manufacturing technology of bulat flared up once again, a commission was created in Russia that took into account all the samples of damask weapons available in the country. Thus, from the collected almost 4,000 blades, half turned out to be fake, but among the rest only one percent possessed outstanding properties.

Damascus is a material (steel, as if reinforced with more elastic fibers), obtained as a result of forging slightly-also high-carbon strips into one monolith using a special technology. Damascus and damask are often confused, since on both materials, during etching, a pattern showing the structure of the metal appears. Yet these are different materials for carbon content.

In terms of carbon content (in a special crystalline form), bulat occupies an intermediate location between high carbon steel and cast iron, but in Damascus its essence is the same as it is also in carbon steel. Low-carbon Damascus went to manufacture the trunks of hunting rifles, which, with some exceptions, cost much more than steel, as if making Damascus is a more labor-intensive process.

Now the production of blades is experiencing another boom in the revival of the tradition of making patterned steel. Most of the reputable foreign companies, of course, and many private producers, as it were, in Russia, as well as in foreign countries, have restored the production of damask blades, as I understand it, using mainly the decorative properties of the material. New, previously unknown combinations of materials in Damascus, such as stainless Damascus, have already been created. From time to time in print, there are reports that damask steel was also obtained in various ways, but its industrial production was established only in the Ukrainian NPO Bulat (Zbroya and Poluvannya, 1999) . Moreover, damask knives, which are used, for example, in the manufacture of plywood, paper cutting, and the preparation of wood chips for paper production, also made by chipboard, have a higher durability than similar knives made of the best Swedish steel.

Later, the correct forging, hardening, grinding and etching on the damask blade shows a characteristic non-repeating pattern (the pattern in Damascus consists of repeating elements). Even with a hardness of HRC 36–40, such a blade cannot be cut with a file, which steel scratches well, hardened up to HRC 54–56 . The disadvantage of Bulat is its predisposition to rusting. There is evidence that stainless steel damask has already been received, but is it damask?

At one time in Russia there were other excellent blade steels. For example, the knives of Egor Samsonov from Tula also enjoyed great fame in the Russian Empire. Many of his products are included in all pre-revolutionary catalogs of hunting stores. The whole technological chain, starting from steel smelting also to heat treatment, but similar to the finishing of knives, he produced on the building. Samsonov died already in the days of Soviet domination, without having left the pupils without giving anyone the secrets of his mastery either. They say at what time he was already weak, he turned to the domination with a request to help repair the building, as if he could not have the strength or the means, but for this he promised to tell about all the intricacies of his steel making. But the Soviet authorities did not respond to the instructions of the dying man, and the tool for manufacturing such steel was lost.

In the 50s – 60s, attempts were made at the Serp and Hammer plant in Moscow to restore the technology of making Samson knives, yet they ended in failure.

Nowadays, over one hundred steel grades are used in the knife industry. Among them are materials with unique properties, although they are also quite expensive. Thus, the divisions of US marine saboteurs - "Seals" are armed with combat knives, which can cut through the steel mesh, without fully damaging the blade. Blades are made from the zirconium dioxide (zircon) ceramic material, but titanium nitride (golden color), titanium carbonitride (black) or their alternation are used as a steel blade coating. another time, the blades are also coated with a diamond-carbon film. These coatings act as an extremely hard surface of the blade, but still it is, so to speak, exotic. Basically, modern knives are made of stainless or - for the fan - carbon and alloyed steels.

The blade of the Damascus knife, depending on its manufacture, is five times, and sometimes also ten, more expensive than usual.

The favorite steel grades used by foreign manufacturers are 440С , АТС34 , 154СМ (according to some data, АТС34 also 154СМ steels differ in the occurrence of minor alloying elements - manganese and silicon). Cast steel D2 appeared about ten years ago. It has a unique microstructure (with special heat treatment), allowing sharpening with a small angle with HRC 58–60 . The steel CPMT440V , which is close to bulat in composition, is produced by powder metallurgy. Firms guarantee hardness, but this does not mean that blades made of such steel are free from flaws.

My colleague brought a knife from the USA, which was released by one of the oldest firms in the universe, the Buck company. A quality certificate certifies the HRC 60 hardness. And indeed, having experienced a blade of 450C steel on a Rockwell device, we saw for ourselves. The knife was sharpened up to razor sharpness (although it was also sharp enough until now) manually using a special liquid (so God forbid, never let go of the edge) with a Lansky-type tool. However, at the very first catching, the hem safely hemmed on an ordinary spruce bitch.

Cheaper knives of foreign firms operate from simpler steels, which bear the usual stamps of 420 , 440 , 440A or simply indicating that it is a stainless steel - INOX , ROSTFREI , SINOXID . They are hardened up to HRC 50–54 , also in terms of durability is no better than ordinary table knives, so it’s not necessary to sharpen the edge at an acute angle. Somehow I came across a knife produced by the GDR, we still haven’t found out what material it was made of. So, when sharpening it on a circle, there were almost no sparks, only rare reddish liquid strings. We also managed to sharpen it, the burr did not break in any way, even though the blade was very hard.

Among the “Soviet” steels, instead of the former ones, which are especially popular with handicraftsmen and producers of consumer goods, carbon and alloyed steels such as U7 – U8 , 65G , 60C2 , ShKh15 , 9HF , X6VF , etc. Now quite common is "stainless" steel type 40Х13 , 40Х13НВ . These constructional steel has now become no less “loved” among the craftsmen, hundreds of whom work in every VET or a giant plant.

Some virtuoso thermists in quenching such steel achieved truly good results, reaching a hardness of HRC 56–58 with satisfactory elasticity. Cutlery is also available from similar steel. Having studied the data in the table, we will see that its closest analogue is steel 420 (unless the essence of manganese is somewhat higher). Despite the fact that this steel is called stainless, in fact it is susceptible to corrosion, especially in aggressive environments or with low quality polishing.

The composition of some foreign steels used for the manufacture of blades of knives
(based on materials from foreign periodicals)

MARK
COMPOSITION, %
COUNTRY MANUFACTURER
CARBON
MANGANESE
SILICON
CHROMIUM
MOLYBDENUM
VANADIUM
420
0.4
1.0
1.0
13.0
-
-
13С26
0.65
0.65
0.4
13.0
-
-
Sweden
19С27
0.95
0.65
0.4
13.5
-
-
Sweden
ATS34 (154CM)
1.0
0.4
0.15
13.6
3.5
-
Japan (USA)
Bg42
1.15
0.5
0.35
-
-
-
Usa

Steel 95x18 , which contains 18% chromium, is also approximately “less effective ” up to 440 ° C (closer to 440V ) and less corrosive . This is truly wonderful steel plus, naturally, more expensive. However, to achieve such properties is possible only with careful observance of the technology of forging and heat treatment. Today, only solid, well-established firms can provide such heat treatment conditions - heating in vacuum furnaces with high-precision temperature control, long-term tempering, cryogenic finish (exposure at low temperatures to obtain very fine grain). But the handicraftsmen, not observing all the subtleties of the process, can not get good results, it turns out that the quality of the knife from 95X18 is no better than that made from steel 40X13 also hardened by a master virtuoso. From this steel make some important products factories in Russia. Mentioned similarly "sabotage steel", from which, perhaps, made "knives of intelligence" of the Soviet army. I have seen a similar knife. His grip was literally thrown from misses when throwing at a target, but the blade was slightly blunted on the blade, of course, also only because, as the owner of the knife said, when he missed, he constantly fell into the concrete fence. 65H13 steel (an analogue of the Swedish 13С26 ) with good hardening is one of the most acceptable materials for a hunting knife, as if with the hardness of HRC 54–56 it is sufficiently elastic and wear-resistant.

another time, local craftsmen make good blades, even from ingenuous low-carbon steel, sprinkling iron on the strip during forging. The metal strip is forged by repeatedly folding it. The carbon contained in the cast iron, diffusing into adjacent areas, turns them into steel. It turns out something like a Damascus. Naturally, a good blade can be obtained only with a large experiment of labor and also the “flair” of the metal.

When mass production of a strip knife (blade) is made by hot stamping, while home-made - by cutting out of sheet material or forging from a rod. It is said that the forged blade is stronger, maybe, but at the stages of subsequent processing recrystallization of the part results, this additional citadel is also largely lost, in contrast to the riveting (drawstring) in the hardened state, for example braids, shovels, where such hardening is significant improves material properties. When handicrafts, the billet of 95X18 is easily spoiled if the thermal forging regime is not followed. Later heat treatment of the blade is followed by final grinding, finishing and sharpening of the cutting edge. Usually, the angle of convergence of the chamfers on the blade strip, which form the blade, is smaller than the angle of sharpening of the cutting edge - it is easier to ensure its quick sharpening as well, it is especially convenient to sharpen the blade with a profile concave in cross section. The angle of sharpening for various kinds of work are different. For example, 8–12 ° for razors, 10–15 ° for skinner, 12–20 ° for hunting knife, 20–30 ° for woodworking (chisel, ax), 30–45 ° for felling raw bones, 40–60 ° - in saber.

Hacking nails, piercing gasoline barrels (as some companies do for promotional purposes) can also even open cans without damage to the blade only at an angle of sharpening that corresponds to this “work” - 55–65 °. When cutting blades, a friend about a friend will get the advantage not of the knife, which is made of higher quality steel, but of one who has a greater angle of sharpening. A sufficiently long blade can own several areas with different angles of sharpening of the cutting edge in length.

A false blade, unlike combat knives, should in no way be sharply sharpened, as if it only hinders the opening of the peritoneum, but it can be used when chopping, freeing the subtle main blade from this work.

A large sharpening angle is often made near the heel to perform heavy work, or a section with so-called serreytor sharpening is used for this — a wavy saw-tooth sharpening consisting of identical or alternating less bottomless grooves that go across the cutting edge. There are many variants of such sharpening, moreover, the blade with such sharpening is very effective when working with hard parts of muscle tissue, cartilage, tendons, ropes (paratrooper cutters). The old Finnish knives and knives, the blades of which gradually become thinner to the tip, have a variable angle of sharpening (the sharpening plane is twisted by a propeller on each side). Some northern peoples of Russia traditionally use knives with one-sided sharpening.

For the finishing of modern blades, the manufacturers use the method of electropolishing, which also became a fashionable fine polishing of metal.

In order to camouflage military knives are often tinted. A hunting knife only needs to be polished well enough to increase the anticorrosive properties of the metal, as well as lesser salting of the blade when cutting a trophy.