Basic requirements for smelting quality of bearing steel

The quality requirements for bearing steel smelting

Bearings are widely used in all kinds of machines, and bearing steel accounts for a large proportion in the bearings. The quality of bearing steel smelting directly affects the performance of the bearings. Bearing steel is a very important part of bearing production. In order to ensure the use performance of bearings, especially the rotating accuracy, life and reliability of bearings, higher quality requirements and technical conditions must be met.

1. The composition and content of chemical elements of bearing steel should meet the provisions of the relevant national standard;

2. Bearing steel must have good cleanliness, and the impurities are mostly non-metallic inclusions such as oxides, sulfides, and hydroxides, which can be tested by an optical microscope. The shape of the inclusions is related to the manufacturing process and materials, and the size should not exceed the allowable limit;

3. The bearing steel must have good metallographic structure, the microstructure should be fine and uniform, the size of pearlite and ferrite grains is not large, and there should be no large crystal grains, coarse and skin spots, etc. The properties of bearing steel are good or bad. All depend on the general structure, organization and position of the structure components;

4, bearing steel mechanical properties must meet the requirements of the relevant national standard, should have good strength, hardness, plasticity and toughness, etc., to ensure that the bearing has good fatigue resistance, wear resistance, corrosion resistance and other performance requirements;

5. The heat treatment of bearing steel should be accurately controlled, and the requirements of heat treatment should meet the relevant national standard, not too large or too small;

6. The quality of the surface of bearing steel should be good, there should be no obvious defects, and the surface should have good smoothness, no pitting, fold marks, ripples, scratches and other defects;

7. The dimensional accuracy of bearing steel should also meet the requirements of the relevant national standard. There should be no obvious discrepancy between its own size and the dimensional design requirements.

In short, the quality requirements of bearing steel smelting should meet the relevant national standards, and the production enterprises should inspect each process before the smelting furnace, control the quality of the raw materials, strictly implement the metallographic structure and mechanical properties, and strive to improve the pass rate and performance of bearing steel.

Basic Requirements for Steel Smelting Quality of Bearing Steel

1. The chemical composition of bearing steel must ensure that the elements of carbon, alloy and other elements meet the requirements of the industry standard.

2. The density and tensile strength of bearing steel must be up to the industry standard in order to better meet the needs of different bearing products.

3. The surface finish of bearing steel must be up to standard (smooth, bright, free of oil impurities, etc.).

4. After heat treatment and forging, the hardness of bearing steel must meet the requirements of the industry standard to ensure its comprehensive performance.

5. The inclusions of bearing steel must be cleaned up to a certain level in order to reduce the potential problems caused by inclusions.

6. The microstructure of bearing steel should be uniform and fine and there should be no shrinkage cavities, cracks and other defects which affect the overall performance of bearing steel.

7. The isotropy and orientation of bearing steel should meet the requirements of the industry standard so as to ensure its bearing performance.

8. The bearing steel must pass the non-destructive testing, such as ultrasonic and magnetic particle testing, and other surface testing, etc., in order to ensure the quality of bearing steel.