Steel x12MF for knives: characteristics, pros and cons

CHEMICAL COMPOSITION OF TOOL STEEL X12MF

• Chromium (Cr). Content 11 – 12.5%. Chrome increases wear resistance and cutting properties. Makes metal resistant to corrosion.
• Carbon (C). Content 1.45 – 1.65%. Gives steel hardness and durability, increases the resistance of the alloy during heat treatment, and also makes it more durable.
• Molybdenum (Mo) - 0.40 - 0.60%, Vanadium (V) - 0.15 - 0.30%. Silicon (Si) - 0.10 0.40%. Steel is hardened in deep layers thanks to this element.
• Manganese (Mn) – 0.15 – 0.45%. Thanks to it, the alloy is less deformed during hardening.
• Nickel (Ni) - no more than 0.35% and Copper (Cu) - no more than 0.30%. The content of elements in the composition of steel prevents carbon from reacting with other components and improves ductility, and also eliminates brittleness during tempering.
• Phosphorus (P) allows metal to be cast smoothly during the annealing stage and improves ductility. Its content for high-quality steel should be no more than 0.030%.

Steel grade X12

Electroslag surfacing of X12 steel: electroslag surfacing is used if the surface area of ​​the part to be surfaced is large enough. It is performed both in the lower and vertical positions. For high-chromium ledeburite steels of type X12, the main alloying elements are carbon (1.2-2.3%) and chromium (11.5-13.5%). Some of this type of steel is alloyed with minor additions of tungsten, molybdenum, nitrogen, nickel, vanadium and titanium. The main alloying elements give steels high hardness, wear resistance, deep hardenability and low deformability during hardening. After annealing, they are satisfactorily processed by the cutter.

Tools with a deposited layer of steel type X12 are designed for processing particularly hard materials. For surfacing, mainly flux-cored electrode wires with a diameter of 2.8-3 mm and AN-26 flux are used. The chemical composition of cored wires is given in the table below. These wires provide the deposited metal with a standard composition in normal modes of electroslag surfacing (Ic per wire 250 - 500 A, Uc = 30-35 V). The best results were obtained with alternating current.

Workpieces weighing more than 25 kg should be heated before surfacing, and after surfacing, annealed at a temperature of 700 ° C for 1-2 hours with slow cooling. This will avoid the appearance of cold cracks after surfacing.

For subsequent mechanical processing, the deposited product is annealed according to the following regime: heating to 800-870° C, holding for 1 - 4 hours, slow cooling to 700° C, cooling in air; the total cooling time must be at least 10 hours. After mechanical processing, the product is subjected to hardening and tempering. Hardening modes are selected depending on the nature of the operation.

ESSENCE OF THE STEEL PRODUCTION PROCESS

Die tool steel is difficult to machine. It is necessary to strictly follow the quenching and tempering technology in order to obtain a high-quality alloy.

The metal is smelted in electric furnaces, open-hearth furnaces and oxygen converters, strictly maintaining temperatures up to 950 0C. If the temperature regime is violated, the steel will become brittle when cooled and will crumble during forging. Forging temperature 850 – 1140 0C.

The crystal lattice becomes stable after quenching and annealing. Hot metal releases internal tension and becomes solid.

X12MF steel is hardened and tempered several times to make it as strong as possible. The steel sheet is then hammered to give the alloy stability. The endurance of steel is 650 – 800 MPa.

The sheets are fired in a vacuum furnace and sent to metallurgical plants in the form of rolled products, wheels, ground and calibrated rods, strips, sheets and plates, blanks, slabs, forgings and forged blanks.

X12MF steel is cast exclusively in production foundries.

Brief overview of steel 95Х18

This stainless steel is considered one of the best for making knives. This is not my opinion, and not the opinion of Russian knife makers, this is what large manufacturers of Russian knives think. Indeed, there is no point for them to tinker with other types of steel when 95X18 holds an edge well, does not rust and is relatively easy to process. Although in recent years, even large knife companies have to somehow spin around and try new types of steels in order to interest the client.

Despite this, knives made from 95x18 have an excellent price-quality ratio. Blades are hardened to 57-59 HRC, which is quite enough for long-term retention of sharpening, and for relatively easy sharpening. The fact that 95X18 knives do not rust makes them ideal for those users who are not used to caring for knives.

A knife made of 95X18 will forgive even the fact that you put it dirty and wet in the sheath and remember about it the next day. An analogue of steel 95X18 is Japanese steel AUS-8.

STEEL X12MF CHARACTERISTICS, APPLICATION

Alloy steel is indispensable in metallurgy, mechanical engineering, the manufacture of cold-formed tools, and in the production of electrical equipment.

The aviation, motorcycle, and shipbuilding industries actively use the X12MF alloy in the production of parts.

Gears, body and molding dies, hole-punching dies, stampings of electrical machines, rolling dies, dies, dies and punches of cutting dies with complex shapes are made from it. The dies remain sharp even after more than 5,000 blanks have been cut from them.

Stamped tool alloy is considered the best in the production of edged weapons, knives for home use, as well as equipment for hunters and tourists.

X12MF knife steel: pros and cons

Knives made from this steel are unrivaled. But it also has its drawbacks. Let's start with the pros:

• Low cost due to available components.
• Withstands both low and high temperatures.
• The blade of the knives remains sharp without sharpening for a long time.
• There is no need to impregnate the alloy with anti-corrosion agents or constantly polish it. Metal does not rust if used carefully.

Now about the cons:

• To sharpen the blade you need special equipment.
• Limited blade length.
• If steel regularly comes into contact with acids and salts, spot rust forms on the surface.
• The knife is not shiny, but matte.

Steel grade X12MF for knives: pros and cons

Like any other steel, the X12MF grade has its advantages and disadvantages.

Its advantages are:

• high cutting properties;
• reasonable price;
• long-term sharpening retention;
• increased blade strength.

Experts will confirm that steel knives have one peculiarity: a maximally sharpened edge does not hold an edge well and quickly becomes dull. This cannot be said about the X12MF knives. The optimal percentage of carbon provides special resistance to wear, so a product with this marking will remain sharp for a very long time. In camping conditions, you can safely cut down bushes with a knife for a long time, and the blade will still retain good cutting abilities. At the same time, if you still intend to improve the sharpness, then using a stone with diamond chips will speed up the sharpening time.

Steel has its drawbacks. In particular, you should not use a knife made of steel of this marking to cut hard objects (for example, bones) - there is a risk of chips on the blade. Despite a certain level of elasticity, try not to test the knife for bending. The reason for all this is some fragility of the metal.

Production nuances

Industrial production of X12MF steel is established using a proven technical process. Depending on the delivery conditions and customer requirements, the melt is poured into molds or finished molds, taking into account allowances for machining. A small degree of shrinkage allows you to assign minimal allowances.

During cooling and crystallization, the formation of a dendritic structure is inevitable. In this case, the precipitation of carbides occurs unevenly across the cross section of the casting. To eliminate structural heterogeneity, annealing is performed.

Of interest is the production of castings using the electroslag remelting (ESR) method. Its use makes it possible to obtain an isotropic structure in all directions of casting. Metal produced by the ESR method has better forging characteristics. Similar results are obtained using the vacuum arc remelting (VAR) method.

During forging, the structure of the metal is further improved: heterogeneity in composition is eliminated, the dendritic structure is broken up, grains are refined, and voids in the crystal lattice are filled.

The performance properties of blades are significantly influenced not only by the chemical composition, but also by the smelting method. Preference is given to workpieces obtained by ESR, VDP and powder methods.

Rules for using knives made from this material

The main reason for knife failure is the blade breaking. This happens due to the application of bending forces. Steel is very sensitive to loads other than axial ones. Another common problem is loss of aesthetics. This happens when the knife is not properly cared for. To prevent this from happening, you must follow simple precautions:

1. The knife must not be thrown, thrown, dropped, or used as a lever. It is also not recommended to chop bones when cutting carcasses to avoid chips on the cutting edge.
2. It is important to avoid exposing the fabric to an acid-base environment. Pitting corrosion develops very quickly and can ruin the appearance of the product.
3. The ideal sharpening angle is 35 degrees. This value must be adhered to when restoring the cutting edge.

Ignoring these rules is guaranteed to lead to breakage of the knife. The properties and characteristics of a knife made of X12MF steel will help you maintain simple rules for storing the product:

1. It is best to store a knife in a sheath. This method will protect you from accidental falls and related chips.
2. After use, it is better to rinse the knife with running water, wipe it dry with a paper napkin, and lubricate it with petroleum jelly or ballistol.
3. Once every four months it is necessary to polish the blade with GOI paste and edit it on a leather belt. If necessary, use fine-grained diamonds. High-quality polishing reduces the risk of pitting corrosion.
4. The wooden handle of a knife should be regularly treated with an antiseptic. This procedure protects against mold and bacteria. Caring for a metal handle should be the same as caring for a blade.
5. If a corrosion spot is found on the canvas, this place must be lubricated with ballistol. After some time, the stain should come off.

Only recommended gun oils should be used. The use of poor quality oils will lead to a decrease in the quality and technical characteristics of a knife made of X12MF steel.

On a hunt, fishing, picnic, on a camping trip, or in the process of professional activities, a knife made of X12MF steel will become a friend and faithful assistant. With proper care and careful handling, it will retain its properties for a long time and will delight you with its appearance.

It is better to store knives in sheaths

The knife should be rinsed immediately with running water.

It is necessary to polish the steel on time

Treat the handle with antiseptics

So which is better?

Comparing these two steels is not entirely correct. Their working properties are very different. Here you need to focus on functionality. If you need a really working knife that will be used almost every day, then you need to take the X12MF. With such use, it will simply not have time to rust.

And if you rarely use a knife, and most of the time it lies around idle, then it is better to take 95X18. If you don’t use it to cut several carcasses a day, you won’t notice much of a difference in hardness. Although the X12MF blade cuts more aggressively and “juicily”. Words cannot explain it, you have to try it yourself.

Another extremely important point is the thermal treatment of the blades. Not all domestic manufacturers can make it adequately. So then you get under-heated and overheated blades.

So choose a knife according to your needs, but I prefer the X12MF.

Price

The popularity of X12MF steel exists due to its availability and the possibility of using recycled materials.

It is not easy to give more information than there is about the X12MF steel grade, which has been known for 90 years, since the times of the Soviet Union. Over these decades, information about it has been repeatedly given in periodicals in the most expanded format; there is a lot of specialized literature. Used by most of our knife makers. The reason for this popularity is due to the affordability of steel and the stable quality of manufactured products.

Read also: How to remove a rotary hammer bearing

X12MF steel was created by Soviet engineers for the needs of Soviet industry in the 30s of the 20th century. Initially intended for metal processing by stamping. According to the purpose, the biochemical component of the alloy and the entire technological process were developed.

Ratnikovsky knife

Later it was found that the characteristics of the alloy already introduced into production corresponded to the production of edged weapons on an industrial scale. Steel X12MF had all the necessary properties:

• appropriate viscosity;
• stable anti-corrosion properties;
• excellent performance on compression, elasticity, hardness and rigidity.

Therefore, in addition to industrial use, the alloy began to be used for knives made for special forces. For example, military personnel of the NKVD troops were armed with these weapons.