The role of alloying elements in precision bearing rolling bearing steel

China Bearing Network Summary Precision alloy rolling bearing steel alloy elements are mainly silicon and chromium, what are the two roles? Introduced as follows:

1. The role of silicon in GCr15 bearing steel

It is beneficial to the formation of the body-centered cubic ferrite structure. It does not form carbides in the steel. It is on the left side of the iron in the periodic table and is mainly dissolved in iron. It has little effect on the diffusion coefficient of carbon in austenite, and has no effect on the formation rate of austenite. It can raise the A1 point and relatively slow the formation of austenite. If the austenite grain size is slightly hindered or ineffective during heating, the pearlite phase transformation can be delayed to shift the C curve to the right, so that the nose on the C curve moves to a high temperature region, which lowers the Ms point and improves the supercooled austenite. The stability of the body, thereby reducing the quenching critical cooling rate and improving the hardenability of the steel. It can significantly slow down the decomposition of martensite at lower temperature, but does not slow down the decomposition of martensite at tempering at 400-500 °C, significantly hindering the accumulation of carbides, hindering the elimination of various types of distortion in steel during tempering. The effect, and generally delays the recovery, recrystallization and carbide aggregation process of the α phase of the quenched steel, thereby inhibiting the reduction of the hardness and strength of the steel and enhancing the tempering stability of the steel. The recrystallization temperature of the α phase can be increased, the temper brittleness of the steel can be significantly enhanced, the phase structure of the steel can be changed, and the amount of pearlite can be increased. The main purpose is to increase the hardenability of the steel. All the hardened parts can obtain high and uniform comprehensive mechanical properties after high temperature tempering, especially the high yield ratio, which significantly strengthens the ferrite and is more than a certain range. Can improve the toughness of steel.

2. The role of chromium in GCr15 bearing steel

The element of the γ phase region can be blocked. When the content reaches a certain amount, the γ phase region is blocked, even if the γ region on the phase diagram shrinks to a small range, and the γ to α phase transformation occurs in the alloy beyond this content, which is beneficial to the body center. Formation of cubic ferrite structure. Carbide can be formed in steel, which is a transitional over-group element. It is located on the left side of iron in the periodic table, which can reduce the carbon content of the steel at the eutectoid point and the maximum solid solubility of carbon in γ. The phase region disappears and all ferrite structures are obtained. It is a strengthening element forming element, which reduces the diffusion coefficient of carbon in austenite, thus greatly delaying the transformation process of pearlite to austenite. In the steel, the formation of special carbides is not easy to dissolve, which will reduce the austenite formation speed. Slow, can raise the A1 point, relatively slowing the formation of austenite. Significantly, the recrystallization temperature of the α phase is pushed to a high temperature, so that temper brittleness is apparent in the steel, and the further development of martensite decomposition is strongly prevented, and the phase structure of the steel can be changed to increase the amount of pearlite. Increasing the hardenability of the steel, all the hardened parts can obtain high and uniform comprehensive mechanical properties after high temperature tempering, especially the high yield ratio, significantly strengthening the ferrite, and increasing the steel in a certain range. Resilience. If a special carbide which is difficult to dissolve is formed, if the holding time is insufficient during heating, austenite having extremely uneven composition will be obtained. It has a moderate hindrance to the austenite grain size during heating, which can delay the pearlite phase transformation, reduce the Ms point, improve the stability of the supercooled austenite, thereby reducing the quenching critical cooling rate and improving the hardenability of the steel. Significantly hinder the accumulation of carbides, hinder the steel from eliminating various types of distortion during tempering, and generally delay the recovery, recrystallization and carbide aggregation of the α phase of the quenched steel, thereby inhibiting the reduction of hardness and strength of the steel. Enhance the role of manganese in 5.3 GCr15 bearing steel.https://www.supplyforever.com/

The role of cages in INA universal joint bearings

The use factors mainly refer to whether the installation adjustment, use and maintenance, maintenance and repair, etc. meet the technical requirements. According to the technical requirements for the installation, use, maintenance and maintenance of the universal joint bearing, the load, speed, working temperature, vibration, noise and lubrication conditions of the running INA bearing are monitored and inspected. Adjust to bring it back to normal. The installation condition is one of the primary factors in the use factor. The bearing is often changed due to improper installation, and the force state between the parts of the whole bearing changes. The bearing is operating in an abnormal state and the end of the service life is early. Refers to the three major factors that determine the quality of the bearing, such as structural design, manufacturing process and material quality.
The metallurgical quality of bearing materials used to be a major factor affecting the early failure of universal joint bearings. With the advancement of metallurgical technologies (such as vacuum degassing of bearing steels), the quality of raw materials has improved. The proportion of raw material quality factors in bearing failure analysis has dropped significantly, but it is still one of the main factors affecting INA bearing failure. The proper selection of materials is still a factor that must be considered in bearing failure analysis.
The bearing is a structure of a tape carrier and a cage. Among them, large-sized bearings are generally required to bear a large load, often without a cage, but filled with rolling elements between the inner and outer raceways. Most small and medium-sized rolling bearings are equipped with cages.
In the INA bearing process, how the outer ring, inner ring, rolling element and cage of the universal joint bearing are assembled. Simply put, the inner and outer rings of the bearing are placed first, the inner ring is placed sideways, then the rolling elements are placed (on one side), then the position of the rolling elements is adjusted, and finally, the cage is placed. Now everyone knows that there is also a cage in the processing of the bearing, so what is the main function of the bearing cage?
The role of the cage is:
1. Guide and drive the rolling elements to roll on the correct raceway;
2. The cage separates the rolling elements from each other and is evenly distributed on the circumference of the raceway to prevent the rolling bodies from colliding and rubbing during work;
3. In the split type bearing, the rolling element and a ferrule are combined to prevent the rolling elements from falling off.
The bearing is called a window and is used to isolate and guide the rolling elements. The pocket clearance allows the cage to have a certain amount of motion in the radial and axial directions. The total radial activity is called the gap of the cage. There are many types of structures and complicated shapes in the roller cage. There are many equidistant pockets on the cage. The shape of the pockets is spherical, round, elliptical, rectangular and toothed. The size of the pocket is larger than the size of the rolling element. The difference between the two is pocket clearance, sometimes for the bearing cage window. The portion of the connection between them is called a lintel, which acts to connect and increase the strength of the cage.

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