TECHNICAL SPECIFICATIONS:

Knife name: MALYUK handmade knife by Oleksandr Repa, buy to order in Ukraine, powder steel - M390, 61 HRC
Knife type: Fixed blade
Brand:  OLEKSANDR REPA Handmade Knife Workshop

M390 powder steel: composition, decoding and application

Damascus steel has long held a leading position in terms of strength, reliability and durability. Modern technologies have allowed us to obtain a new type of material with the best performance - M390 steel. It was first introduced in Austria by Bohler-Uddeholm AG in the early 1990s.

Due to its high technological characteristics, the material quickly gained recognition and began to be used for the manufacture of knives. Its main properties include:

• Hardness (60-62 HRC) is due to the unique structure of the crystal lattice with a solid structure. This result was obtained on the basis of careful adjustment of the composition and ratio of components. Steel grade M390 is subjected to hardening, which significantly increases its strength.
• The use of vanadium and tungsten. Sharpening knives is carried out using tabletop units, since the use of a water stone will significantly complicate the process. After such processing, the knife remains sharp for a long time.
• The possibility of mirror polishing due to the high hardness of the metal. The smooth polished surface of M390 steel is characterized by the same reflective ability as a mirror.

Decoding and chemical composition
Today, the composition is widely used for the manufacture of cutting tools, including knives. It refers to materials of the powder production method, during its processing, the raw material is crushed and baked in molds at a temperature of up to 1500 degrees. This allows the use of a significant part of the alloying elements, which improves the characteristics of M390 steel.

The development of the metal was carried out on the basis of EU standards, according to which the chemical composition of M390 steel, in addition to iron, includes:

• Carbon in the amount of 1.85±0.05%. It is necessarily present in the metal of high hardness, binding the molecules of Ferrum (Fe) increasing mechanical properties. On the other hand, its presence worsens the processability of processing and increases brittleness. However, steel is considered the optimal material in the ratio of brittleness to strength.
• Chromium is contained in steel in an amount of 20±1%. It is intended to improve mechanical performance and corrosion resistance as a result of heat treatment. Increasing the concentration of this chemical element in steel grade M390 guarantees an extension of the period of trouble-free operation under cyclic loading and abrasive action.
• Silicon and manganese are contained in the metal in the amount of 0.7±0.1% and 0.25±0.05%, respectively. They are deoxidizers that prevent chemical elements from the air from entering the alloy during manufacturing. Due to them, chemical leaching is reduced, strength and surface quality are increased.
• Molybdenum and vanadium are contained in amounts of 1% and 3-4%, respectively. They are characterized by a high melting point, which increases the material's resistance to elevated temperatures, hardness, and improves technical properties.
• Tungsten in steel in an amount of 0.6±0.1%. It increases its strength and has the maximum effect on this indicator compared to other components.

Material features

The advantages of the alloy include:

• excellent plasticity with significant hardness;
• corrosion resistance, inability to oxidize in air and at t = 800 degrees;
• lack of reaction to the effects of many acidic and alkaline substances;
• preliminary heat treatment, which includes hardening and high tempering;
• strength that ensures failure under significant load, which is 1.4 times higher than the similar indicator of high-speed steels. The difference between the yield strength and tensile strength is practically absent;
• Knives made from M390 stay sharp for a long time.

The only disadvantages are the cost of the material and the difficulty of sharpening and grinding.

Knife from M390

Technical characteristics
M390 steel is characterized by the following main parameters:

• melting point 1300-1400 degrees;
• hardness 65 units according to Rockwell;
• ultimate strength of 900 MPa;
• the beginning of destruction is 850 MPa.

Application
The metal is used to make knife blades, surgical instruments, and industrial cutters. Knives are characterized by high hardness and the ability to withstand strong dynamic effects. They remain sharp for six months if the operating rules are followed. The only negative qualities are the difficulty of sharpening, which requires special equipment - a machine tool. It is also important to have skills in this process.

Analogues

Only the American product Duratech 20CV can be considered an analogue of M390 steel, which is due to the recent appearance of the metal on the market.

I also recommend looking at the following steel grades:

40XN;
12X18X10T.

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Vulcanized fiber

Vulcanized fiber is a composite material made of cellulose (cotton and cellulose fibers). The name is borrowed from the process of vulcanizing natural rubber to produce ebonite, which at first glance is very similar to the process of producing vulcanized fiber. In the production of vulcanized fiber, ribbons of cotton and/or cellulose fibers are passed through a parchmentizing bath with a solution of zinc chloride or sulfuric acid, as a result of which the fibers are slightly dissolved. The liquid is then squeezed out, as a result of which the individual fibers and ribbons are connected to each other without any binders.

Due to its high strength and stability, combined with its low weight and good elasticity, vulcanized fiber is used today not only for stamped parts, gaskets, laminate substrates and other industrial products, but also as a base for grinding wheels, so-called vulcanized disc grinding wheels or even short fiber wheels. For this, bases with a thickness of between 0.38 and 0.84 mm are usually used.

Vulcanized fiber can withstand high temperatures of up to 110° C for a long time. Therefore, when working with fiber wheels, high pressure and grinding in place should be avoided, as this can lead to blistering and burning of the wheel, i.e. tearing out the grain.
The cellulose that forms the basis of vulcanized fiber is hygroscopic, i.e. it can absorb moisture from the environment and give it away, as a result of which the volume of the fibers changes. In fiber wheels that are exposed to too high or too low air humidity, this effect leads to curling of the wheels. It is therefore recommended to store the wheels at medium air humidity (relative air humidity approx. 45-65%).

Vulcanized fiber is used by Klingspor as the basis for fiber discs. Here, Klingspor offers a wide range of products for various applications.

HANDLE MATERIAL - MAMMOTH TUSK

Mammoth tusk is a rare raw material used to make decorative items, such as knife handles, gun grips, and jewelry. It is a unique natural element that is rarely found, so its value is quite high.

Today, mammoth tooth, after certain processing (stabilization), is widely used by master knifemakers. Stabilization is the process of polymerizing the material under vacuum with or without the use of fat-soluble dyes, while the material is impregnated with polymeric substances throughout.

MAMMOTH TOOTH HANDLE MATERIAL

Mammoth tooth is a manufactured material of animal origin. Its exceptional feature is the fact that its source is extinct animals - mammoths. Paleontologists have established that they lived on Earth about 10 thousand years ago, and their number was very large. The teeth of mammoths were not permanent and changed about four times during their lives. The fallen teeth, which modern scientists find during excavations, become the basis for decorative elements, including knife handles.

Due to the long stay in the soil, the material acquired a very unstable structure - the enamel became rock hard, and the dentin, on the contrary, became loose. But modern technologies for stabilizing materials have helped turn mammoth teeth into an excellent basis for creating luxurious knife handles. The polymer composite provides the products with resistance to corrosion and moisture, and the natural base gives a unique texture and intricate pattern.

Material features

Mammoth molars are used to create various products. Outwardly, they resemble elephant teeth, but they have a much different shade. Given the historical value and rarity, mammoth tusk is especially highly valued, since this animal became extinct long before our era. Tusks of prehistoric giants can be found not only in paleontological museums, but also on the shelves of jewelry stores, they are used to decorate the interior, used to create various decorative elements - of course, not in their original form, but in processed form.

The age of the material, according to scientists, is 10-40 thousand years. How mammoths lived has not been fully studied today. However, the remains of these giants found by scientists, their bones, teeth, even whole carcasses have allowed scientists to make serious progress in this field of research. The available data made it possible to find out what the mammals looked like, what they ate, what climatic conditions they lived in, what behavioral characteristics they had (for example, whether they led a herd or solitary existence).

The mammoth ate practically the same as a modern elephant: its diet consisted of plant food. In the world, the animal could feed on coniferous plants. They preferred rough food, which they easily chewed with their strong jaws and teeth, similar to large plates. An interesting feature of the mammoth's body was that as the old tooth wore out, a new one grew, displacing the old one and taking its place. Thus, the animal could change its teeth several times during its life. Absolutely all teeth changed in about a ten-year period, and the average life span of a mammoth was 40 years. In other words, one animal could survive an average of four complete changes of molars. It is because of this feature that people often find individual worn mammoth teeth but do not encounter other traces of it.

Appearance

If you look at a mammoth tooth, you can see a heterogeneous surface with ribbed edges. Bone, enamel and soft tissue in this case alternate. The material has a rather complex structure:

Its basis is dentin.

The dentin layer is covered with protective enamel.

It is worth noting that the mammoth had only 4 molars and 2 tusks, which protruded outward and served mainly for self-defense.

After special processing, the molar can be used to make various jewelry products. The density of the material is very high and resembles stone. In order to process such a product, the master needs to spend a lot of effort and time.

Raw material stabilization

To prevent the tooth and tusk from collapsing during use and manufacturing of products from it, stabilization technology is used. This is a crucial stage of processing, in which the following technologies are used:

Polycondensation.
Vacuum processing.
Application of special dyes.

All cavities of the tooth are filled with a polymer substance, due to which the base acquires reliable protection from climatic influences. Such a product does not deform, cracks do not appear on it, it becomes able to withstand high temperatures. The appearance of the material also changes, becomes more attractive and unique.

Ironwood - iron wood - handmade knives

In nature, ironwood is extremely rare, so it occupies an honorable place in the Red Book. However, in terms of its properties, each ironwood is not inferior in density to cast iron. Its bark can withstand fire from firearms, but at the same time it hopelessly sinks in water. It is worth noting that this is not a separate class of trees, but a whole group collected from different species. It includes several dozen species of plants with unusually dense wood. They can be found on each of the continents. Moreover, the raw materials are used both in the industrial industry and in medical practice.

What is special about these trees?

It is quite difficult to recognize a "stone" species of perennial plant with the naked eye. Especially if they are on the verge of extinction. However, they are characterized by the following features:

• the age of such long-livers is at least 2 hundred years;
• wood fiber is resistant to corrosion processes and does not deteriorate under the influence of strong acids;
• the bark contains many tannins that protect their "owners" from all kinds of parasites, as well as from rotting fungi;
• the log will definitely go under water, since the density of wood is 1 t / m³, taking into account the humidity of 12%, for this reason such species grow quite slowly;
• The height of each exceeds 25 meters, and the trunk circumference reaches more than 200 cm.

All these properties are necessary for the iron tree to survive in the harshest climatic conditions. Sharp temperature drops in Russia, African drought or humid European climate will not be able to harm this phenomenon of nature. Such tree species adapt perfectly in any adverse environment. For this purpose, they are equipped with a considerable number of adaptations, ranging from the unique structure of the trunk / roots and ending with the chemical composition of the bark. In this regard, they are widely used in production:

• furniture;
• building structures;
• cars;
• cosmetics;
• decorative elements;
• underwater equipment.

Before the advent of this technology, mammoth teeth and bones were rarely used for making souvenirs, because they did not have sufficient strength due to the large number of cracks and delaminations inside. In addition, tooth enamel has high hardness, which quickly leads to the unusability of the saw when processed. A stabilized product is much easier to further process. Mammoth tooth has become especially popular in the manufacture of knife handles. It looks unusual, attractive, and if you add dye, you can create a unique pattern that can give even such a rare thing a special individuality.