Steel SHKH15: characteristics, application properties, the decryption of the marking

Features of steel SHKH15, as well as the production process has led to the fact that it was attributed to the group of structural steel.

Steel Structure

The most Important requirement for this type of steel is high hardness. In order to achieve this indicator, use a large amount of carbon as an alloying element, and add a certain amount of chromium.

At the time of delivery of the steel structure is a ferrite-carbide mixture. Often when you supply this kind of write it - annealed for granular perlite. It is also important to note that the application characteristics of steel SHKH15 applies high ductility, which must be met, as the raw material of this brand is often used for the production of various plastic designs.

Temperature tempering of steel, in which it passes the heat treatment, - 830-840 degrees Celsius. Holiday of raw materials is carried out at a temperature of 150 to 160 degrees, and the time required for the completion of the operation is 1-2 hours.

Carbide phase

Further features of the use of steel SHKH15 is largely dependent on the carbide phase and its successful completion. If we consider its flow under the microscope, we can observe that upon successful completion, the effort required for destruction of the matrix 140 kN.

To achieve this figure, the ball, which is the main element of the structure must have a homogeneous matrix, but also sufficiently uniform carbides. Same they should be in size and their distribution in the matrix. If during the processing something went wrong, the force required for destroying the structure, may fall to 68 kN. If this happens, then the ball structure turned out uneven. The carbides in this case can be located unevenly and/or have unequal size. This figure is very significant for the steel.

Defects in the carbide phase

As well as the characteristics of the use of steel SHKH15 is largely dependent on the flow of the carbide phase, it is important to know what can be the defects of this process:

• One of the first defects is carbide banding. It arises from the fact that there is heterogeneity of the structure of steel after quenching. In those areas where there are a large number of carbides, martensite appears-troostite structure, and in those places where the quantity of the substance is small, there is acicular martensite.
• Another defect that may occur is a carbide liquation. In bearing type of steel is often found major inclusion of carbides, which are arranged along the direction of rolling is called carbide liquation. The defect of this phenomenon lies in the fact that these elements are characterized by high strength and high fragility. Most of these elements are destroyed at the exit of steel on the working surface of which is formed a hearth of destruction. Pronounced defect of this type greatly increases the wear of steel ball bearing.

Bearings of steel

Due to the application characteristics of steel SHKH15 steel it is often used for the production of balls, rollers and bearing rings.

It is Worth noting that when these parts are constantly subjected to high alternating stresses. It is also important to understand that the roller or ball, and the path of the rings are experiencing a high load at a single point in time, which is distributed over a very small section of the plane. In such areas alternately occur such alternating voltage of the order of 3-5 MN/m² (300-500 kgf/cm²).

It is because of these loads, the quenching temperature of steel is very high, to give high strength to the material. It is also important to note that these high loads do not pass without a trace, they leave a small deformation of the bearing elements. Because of this, formed in the bearing fatigue cracks. The appearance of these defects leads to the fact that with the passage of this section there is an impact, which deformation only increases, and eventually the bearing completely fails.

Bearing steel: features

This steel grade is used for production of balls with a diameter of 150 mm, roller diameter up to 23 mm, and for the production of bearing rings, the wall thickness of which is 14 mm. Also this steel can be used for the manufacture of bushings of the plunger,injection valves and other parts for which the main requirement is high hardness, high wear resistance and contact strength.

Bearing steel of this brand also has a number of specific characteristics, such as: a propensity for brittleness or placentocentesis. The limits of short-term strength of this material are in the area from 590 to 750 MPa. The limit of proportionality for a given material - 370-410 MPa. Elongation of material at rupture is 20%. Steel grade SHKH15 has a relative narrowing of 45%. In addition, there is the feature of impact resistance, the rate of which is 440 kJ/m².

Properties of steel SHKH15

If we talk about the properties of this brand, then you need to pay attention to its chemical composition, which largely affects the formation of these properties. The SHKH15 steel in its composition contains such chemical elements:

• S - 0,95 -1.0;
• Si 0,17-0,37;
• Mn - 0,2-0,4;
• Cr - 1,35-of 1.65.

Also, this brand is characterized by another parameter - the critical point temperature. For steel SHKH15, the figure is in the area from 735 to 765 degrees Celsius.

To achieve the desired strength, this type of alloy is subjected to strong heating, the temperature exceeds eutectoid transformation. It provides the desired concentration of such elements as C and Cr in the steel composition in solid form, and makes the structure fine, uniform grain.

Transcript of steel SHKH15, which is obtained as a result of all these operations is as follows: the letter W denotes that the material belongs to the group of bearing steel, and the letter X indicates that the composition of the raw material includes such material as chromium, which is one of alloy elements.

Carbon steel

Steel SHKH15 - carbon and alloyed steel, which is in the manufacture of knives acquired the name "carbon". This material is used already for about 100 years. The main applications of this material is the bearing, wear-resistant and cutting parts or elements.

It is Also worth noting that this group of steel is a classic for the manufacture of knives and abroad. The knife of SHKH15 will have a huge strength and considerable sharpness. These products are used most often for any cutting tools, but it can be made of conventional kitchen knives.

Features of use

Transcript of steel SHKH15 speaks for itself, but it is worth adding that the 15 a measure of the amount of chromium in the material which it contains in an amount of 1.5%.

When using the products of this steel in the metastable environment with high loads, it is quite possible geometric changes of the detail dimensions. After observation of hardened samples and their changes in size, and after the radiographic studies people found that to stabilize such substances as martensite, tempering of the necessary raw materials for 2-4 hours at a temperature of 150 degrees Celsius. If it is necessary to stabilize the martensite for further use of the substance at elevated temperature conditions, the release process should take place at a temperature threshold that will exceed the operating temperature of 50-100 degrees Celsius.

It Can be noted that the main reason why, after quenching and tempering, the steel changes its geometrical parameters is the influence of residual austenite. To illustrate, one can imagine such a statement: 1% autentica the transformation to martensite will change the size of the part of 1•10^-4. For a more understandable definition this means that the resizing will occur at 10 µm per 100 mm size.