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What factors will affect the performance of bearing steel balls
High dimensional precision steel is required for rolling bearing steel balls, as most bearing parts are pressure formed.
If the dimensional accuracy of steel is not high, it can save materials and improve labor productivity. The bearing sleeves are mostly forged, the steel balls are cold bent or hot rolled, and the small rollers are also cold bent. The calculation of cutting size and weight is inaccurate, and the quality of bearing parts cannot be guaranteed. The equipment and molds are easily damaged. The bearing steel balls require particularly strict non-uniformity of carbides.
If the distribution of heavy carbides is 11, it is easy to cause uneven microstructure and hardness during heat treatment, and uneven steel has a significant impact on fatigue strength.
The unevenness of carbides can easily lead to cracking of bearing parts during quenching and cooling processes. The unevenness of carbides may also lead to the fracture of bearing parts. Due to the shortened service life of bearings, there are specific requirements for different specifications of steel in the bearing material standards.
The strict chemical composition requirements are mainly for high carbon chromium bearing steel balls used in ordinary bearing steel balls, which have a carbon content of about 1, added about 1.5 chromium, and a small amount of manganese and silicon hypereutectoid steel.
Chromium can improve heat treatment performance, hardenability, microstructure uniformity, and tempering stability. It can also improve the rust resistance and wear resistance of steel.
However, when the chromium content exceeds 1.65, the chromium content in the quenched residual austenite steel will increase, thereby reducing hardness and dimensional stability, increasing the unevenness of carbides, and reducing the impact toughness and fatigue strength of the steel.
Therefore, bearings with high chromium content in high carbon chromium typically control the temperature of the steel below 1.65. Only by strictly controlling the chemical composition of bearing steel balls can the microstructure and hardness that meet bearing performance be obtained through heat treatment processes. Bearing steel balls require particularly severe surface and internal defects.
Surface defects include cracks, inclusions, burrs, oxide scales, etc. Internal defects include shrinkage, bubbles, white spots, severe porosity, and segregation. These defects will have a significant impact on bearing processing, bearing performance, and service life, and the bearing material standards explicitly prohibit the use of these defects.
Bearing steel balls are a general term for steel used to manufacture various rolling rings and rolling elements that operate in different environments. High carbon chromium bearing steel balls have a history of over 100 years since their introduction in the early 20th century. Since its inception, the content of chemical elements has hardly changed, but due to the improvement of the purity of bearing materials, their fatigue life has doubled or even tens of times. The improvement of the purity of bearing steel balls mainly depends on the modernization of metallurgical processes and the widespread adoption of external refining technologies.
Heat treatment is the process of changing the internal structure of a metal (some including surface chemical composition) through heating and cooling to achieve the desired performance. These properties include process performance, mechanical performance, and chemical performance. In modern mechanical manufacturing, it mainly refers to the strength, hardness, toughness, wear resistance, heat resistance, and corrosion resistance of materials. Therefore, heat treatment is an important way to improve the performance of parts, ensure product quality, transform processing technology, fully tap into material potential, and save raw materials.
If the dimensional accuracy of steel is not high, it can save materials and improve labor productivity. The bearing sleeves are mostly forged, the steel balls are cold bent or hot rolled, and the small rollers are also cold bent. The calculation of cutting size and weight is inaccurate, and the quality of bearing parts cannot be guaranteed. The equipment and molds are easily damaged. The bearing steel balls require particularly strict non-uniformity of carbides.
If the distribution of heavy carbides is 11, it is easy to cause uneven microstructure and hardness during heat treatment, and uneven steel has a significant impact on fatigue strength.
The unevenness of carbides can easily lead to cracking of bearing parts during quenching and cooling processes. The unevenness of carbides may also lead to the fracture of bearing parts. Due to the shortened service life of bearings, there are specific requirements for different specifications of steel in the bearing material standards.
The strict chemical composition requirements are mainly for high carbon chromium bearing steel balls used in ordinary bearing steel balls, which have a carbon content of about 1, added about 1.5 chromium, and a small amount of manganese and silicon hypereutectoid steel.
Chromium can improve heat treatment performance, hardenability, microstructure uniformity, and tempering stability. It can also improve the rust resistance and wear resistance of steel.
However, when the chromium content exceeds 1.65, the chromium content in the quenched residual austenite steel will increase, thereby reducing hardness and dimensional stability, increasing the unevenness of carbides, and reducing the impact toughness and fatigue strength of the steel.
Therefore, bearings with high chromium content in high carbon chromium typically control the temperature of the steel below 1.65. Only by strictly controlling the chemical composition of bearing steel balls can the microstructure and hardness that meet bearing performance be obtained through heat treatment processes. Bearing steel balls require particularly severe surface and internal defects.
Surface defects include cracks, inclusions, burrs, oxide scales, etc. Internal defects include shrinkage, bubbles, white spots, severe porosity, and segregation. These defects will have a significant impact on bearing processing, bearing performance, and service life, and the bearing material standards explicitly prohibit the use of these defects.
Bearing steel balls are a general term for steel used to manufacture various rolling rings and rolling elements that operate in different environments. High carbon chromium bearing steel balls have a history of over 100 years since their introduction in the early 20th century. Since its inception, the content of chemical elements has hardly changed, but due to the improvement of the purity of bearing materials, their fatigue life has doubled or even tens of times. The improvement of the purity of bearing steel balls mainly depends on the modernization of metallurgical processes and the widespread adoption of external refining technologies.
Heat treatment is the process of changing the internal structure of a metal (some including surface chemical composition) through heating and cooling to achieve the desired performance. These properties include process performance, mechanical performance, and chemical performance. In modern mechanical manufacturing, it mainly refers to the strength, hardness, toughness, wear resistance, heat resistance, and corrosion resistance of materials. Therefore, heat treatment is an important way to improve the performance of parts, ensure product quality, transform processing technology, fully tap into material potential, and save raw materials.