Basic instrumental materials: types, brands, properties, characteristics, materials of manufacture

The basic requirements for tool materials are hardness, resistance to wear, heat, etc. Compliance with these criteria allows cutting. In order to carry out the introduction into the surface layers of the article being processed, the cutting blades for cutting the working part must be made of strong alloys. Hardness can be natural or acquired.

For example, tool steel of factory manufacturing is cut easily. After processing by mechanical and thermal method, as well as grinding and honing, the level of their strength and hardness increases.

How is hardness determined?

Characteristics can be determined in many ways. Tool steels have Rockwell hardness, hardness has a numerical designation, and also letter HR with a scale A, B or C (for example, HRC). The choice of tool material depends on the type of metal being processed.

The most stable level of functioning and low wear of blades that have undergone heat treatment can be achieved with an HRC score of 63 or 64. At a lower value, the properties of the tool materials are not so high, and at high hardness they begin to crumble due to brittleness.

Metals with a hardness of HRC 30-35 are perfectly treated with iron tools that have been heat treated with an HRC of 63-64. Thus, the ratio of hardness is 1: 2.

For the treatment of metals with HRC 45-55, it is necessary to use devices based on hard alloys. Their indicator is HRA 87-93. Materials based on synthetics can be used in the treatment of steels subjected to hardening.

Strength of instrumental materials

In the process of cutting, the working part is affected by a force of 10 kN and higher. It provokes a high voltage, which can lead to the destruction of the instrument. To prevent this from happening, materials for cutting must have a high coefficient of strength.

The best combination of strength characteristics are tool steels. The working part, made of them, perfectly withstands a heavy load and can function for compression, torsion, bending and stretching.

The effect of the critical heating temperature on the tool blades

When heat is released during the cutting of metals, their blades are exposed to heat, more often to the surface. When the temperature is below the critical level (for each material it has its own), the structure and hardness do not change. If the heating temperature becomes higher than the allowable rate, then the hardness level drops. The critical temperature is called reddishness.

What does the term "red resistance" mean?

Redness is called the property of the metal when heated to a temperature of 600 ° C glow in a dark red color. The term implies the preservation of metal hardness and resistance to wear. At its core is the ability to withstand the effects of high temperatures. For different materials there is a limit, from 220 to 1800 ° C.

Due to what the efficiency of the cutting tool can be increased?

Tool materials of the cutting tool are characterized by increased functionality with increasing temperature stability and improving the heat dissipation released on the blade during cutting. Heat helps increase the temperature.

The more heat is diverted from the blade into the device, the lower the temperature on its contact surface. The level of thermal conductivity depends on the composition and heating.

For example, the content of elements such as tungsten and vanadium in steel causes a decrease in its thermal conductivity, and an admixture of titanium, cobalt and molybdenum causes its increase.

What determines the coefficient of sliding friction?

The coefficient of sliding friction coefficient depends on the composition and physical properties of the contacting materials, as well as on the stresses on the surfaces subjected to friction and sliding. The coefficient affects the wear resistance of the material.

The interaction of the tool with the material that has undergone processing takes place with a constant moving contact.

How do the tool materials behave in this case? Their species are equally worn out.

They are characterized by:

• The ability to wash the metal with which it contacts;
• Ability to show resistance to wear, that is, resist resistance to the erasure of another material.

Wear of blades occurs constantly. As a result of this, the devices lose their properties, and the shape of their working surface also changes.

The wear resistance index can vary depending on the conditions under which cutting takes place.

Which groups are divided into tool steels?

The main instrumental materials can be divided into the following categories:

• Cermet (hard alloys);
• Cermets, or mineral ceramics;
• Boron nitride based on synthetic material;
• Diamonds on a synthetic basis;
• Tool steels on a carbonaceous basis.

Instrumental iron can be carbon, alloy and high-speed.

Tool steels on a carbon basis

Carbonaceous substances began to be used for making tools. Their cutting speed is low.

How are the tool steels labeled? Materials are indicated by a letter (for example, "Y" means carbonaceous), and also by a figure (indicators of tenths of a percent of the carbon content). The presence of the letter "A" at the end of the marking indicates a high quality of steel (the content of such substances as sulfur and phosphorus does not exceed 0.03%).

Carbonaceous material characterizes hardness with an HRC of 62-65 and a low level of resistance to temperatures.

The grades of tool materials U9 and U10A are used in the manufacture of saws, and the series U11, U11A and U12 are designed for hand taps and other tools.

The level of resistance to the temperature of steels of the series U10A, U13A is 220 ° C, therefore the tool from such materials is advised to be used at a cutting speed of 8-10 m / min.

Alloyed iron

The alloyed tool material can be chromous, chromosilicate, tungsten and chromotungsten, with an admixture of manganese. Such series are designated by numbers, and also they have letter marks. The first left digit indicates the carbon content factor in tenths of a fraction if the content of the element is less than 1%. Right figures symbolize the average indicator of the doping component in percent.

The grade of the tool material X is suitable for the manufacture of taps and dies. Steel B1 is suitable for the manufacture of small drills, taps and reamers.

The level of resistance to temperature for doped substances is 350-400 ° C, so the cutting speed is one and a half times higher than for a carbon alloy.

Why use high-alloy steel?

Various rapid cutting tools are used in the manufacture of drills, countersinks and tap bits. They are marked with letters, as well as numbers. Important components of the materials are tungsten, molybdenum, chromium and vanadium.

The fast-cutting steels fall into two categories: normal and with a high level of productivity.

Steel with normal capacity

To the category of iron with a normal level of performance, the following brands: Р18, Р9, Р9Ф5 and tungsten alloys with an admixture of molybdenum of the P6МЗ, P6М5 series, which retain hardness not lower than HRC 58 at 620 ° С. The material is suitable for processing steels with carbon content and low-alloy category, gray cast iron and non-ferrous alloys.

Steel with increased capacity

This category includes the following brands: Р18Ф2, Р14Ф4, Р6М5К5, Р9М4К8, Р9К5, Р9К10, Р10К5Ф5, Р18К5Ф2. They are able to maintain HRC 64 at a temperature of 630 to 640 ° C. This category includes superhard instrumental materials. It is designed for iron and alloys, which are handled with difficulty, as well as for titanium.

Solid alloys

Such materials can be:

• Metal-ceramic;
• Mineral ceramic.

The shape of the plates depends on the properties of the mechanics. Such tools function at high cutting speed in comparison with high-speed material.

Metal Ceramics

Hard alloys of cermets are:

• Tungsten;
• Tungsten with titanium content;
• Tungsten with the inclusion of titanium and tantalum.

The VC series includes tungsten and titanium. Tools based on these components have increased wear resistance, but the level of resistance to impact is low. Devices on this basis are used for processing cast iron.

The alloy of tungsten, titanium and cobalt is applicable to all types of iron.

Synthesis of tungsten, titanium, tantalum and cobalt is used in special cases when other materials are ineffective.

Solid alloys are characterized by a high level of resistance to temperature. Materials from tungsten can retain their property with HRC 83-90, and tungsten with titanium - with HRC 87-92 at a temperature of 800 to 950 ° C, which makes it possible to operate at a high cutting speed (from 500 m / min to 2700 m / Min when processing aluminum).

For the processing of parts that are resistant to rust and high temperature, tools from a series of fine-grained OM alloys are used. Brand VK6-OM is suitable for finishing, and VK10-OM and VK15-OM - for semi-finished and rough.

Even more effective when working with "difficult" parts are super-hard tool materials series BK10-XOM and VK15-HOM. In them, tantalum carbide is replaced with chromium carbide, which makes them more durable even when exposed to high temperatures.

To increase the level of strength of the plate from a solid, resort to its coating with a protective film. Carbide, nitride and titan carbonite are used, which is applied in a very thin layer. The thickness is from 5 to 10 μm. As a result, a layer of fine-grained titanium carbide is formed. The level of durability of such plates is three times higher than that of plates without special coating, which increases the cutting speed by 30%.

In some cases, materials are used from cermets, which are obtained from aluminum oxide with the addition of tungsten, titanium, tantalum and cobalt.

Mineral ceramics

For cutting tools use mineral ceramics ЦМ-332. She is resistant to high temperature. The hardness index HRC is between 89 and 95 at 1200 ° C. Also, the material is characterized by wear resistance, which allows processing of steel, cast iron and non-ferrous alloys at high cutting speeds.

To make the cutting tools, also use the cermet of the B series. Its basis is made up of oxide and carbide. Introduction of mineral carbide metal carbide, as well as molybdenum and chromium, helps optimize the physical and mechanical properties of cermet and eliminates its fragility. Increases the cutting speed. Semi-cleaning and finishing with a cermet-based device is used for gray malleable cast iron, hard-to-work steel and a number of non-ferrous metals. The process is carried out at a speed of 435-1000 m / min. The ceramics for cutting are resistant to temperature. Its hardness on the scale is HRC 90-95 at 950-1100 ° C.

For the processing of iron, past hardened, durable cast iron, as well as fiberglass, a tool is used, the cutting part of which is made of solids containing boron nitride and diamonds. The index of hardness of elbor (boron nitride) is about the same as that of a diamond. Its resistance to temperature is two times higher than that of the latter. Elbor is characterized by inertness to iron materials. The limit of strength level of its polycrystals at compression is 4-5 GPa (400-500 kgf / mm ² ), and at bending - 0.7 GPa (70 kgf / mm ² ). Resistance to temperature is up to the limit of 1350-1450 ° C.

Also it is necessary to note diamond on a synthetic basis ballas of the ASB series and carbonado of the ASPK series. The chemical activity of the latter to carbon-containing materials is higher. That is why it is used for sharpening details from non-ferrous metals, alloys with a high content of silicon, hard materials VK10, VK30, and also non-metallic surfaces.

The indicator of the durability of carbonate cutters is 20-50 times higher than that of hard alloys.

What alloys are common in the industry?

Tool materials are produced all over the world. Types used in Russia, the United States and Europe, for the most part do not contain tungsten. They belong to the series CST016 and TN020. These models became a replacement for T15K6, T14K8 and VK8 brands. They are used for processing steels for structures, stainless steel and tool materials.

New requirements for tool materials are due to a deficit of tungsten and cobalt. This factor is connected with the fact that in the USA, Europe and Russia, alternative methods of obtaining new hard alloys that do not contain tungsten are constantly being developed.

For example, the tool materials manufactured by the American company Adamas Carbide Co series Titan 50, 60, 80, 100 contain carbide, titanium and molybdenum. The increase in the number indicates the degree of strength of the material. The characteristic of the tool materials of this release implies a high level of strength. For example, the Titan100 series has a strength of 1000 MPa. She is a competitor to ceramics.