Bearing steel new skills and direction

**New Skills and Directions in Bearing Steel Development** Home > Bearing Knowledge > New Skills and Direction of Bearing Steel Bearing steel is primarily used to manufacture the rolling elements and raceways of rolling bearings. To meet the requirements of long life, high precision, low heat generation, high speed, high rigidity, low noise, and high wear resistance, bearing steel must possess high hardness, uniform hardness, high elastic limit, high contact fatigue strength, good toughness, certain hardenability, and corrosion resistance. To achieve these properties, the chemical composition of bearing steel must be strictly controlled, with attention to the uniformity of components, the type and content of non-metallic inclusions, carbide particle size, and their dispersion and decarburization. Over time, bearing steels have evolved toward higher quality, more functionality, and greater variety. They are classified based on their characteristics and operating conditions, including high-carbon chromium bearing steel, carburized bearing steel, high-temperature bearing steel, stainless bearing steel, and special bearing materials. With the growing demand for high-temperature, high-speed, high-load, corrosion-resistant, and radiation-resistant bearings, new types of bearing steels with special functions have been developed. Techniques such as vacuum melting, electroslag remelting, and electron beam melting have been introduced to reduce oxygen content in the steel. Large-volume bearing steels are now produced using electric arc furnaces combined with LF/VD or RH refining and continuous casting and rolling processes, ensuring high-quality, energy-efficient production. In heat treatment, the process has evolved from bottom-furnace and cover-furnace methods to continuous, controllable atmosphere annealing. Modern continuous heat treatment furnaces can be over 150 meters long, ensuring stable and uniform spheroidization of the microstructure and minimal decarburization. Since the 1970s, with economic growth and industrial advancements, the use of bearings has expanded globally, promoting international standardization and the development of new technologies and equipment. Countries like Japan and Germany have established high-purity, high-quality production lines, achieving significant improvements in steel cleanliness and fatigue life. For example, the oxygen content in Japanese and Swedish bearing steels has dropped below 10 ppm. The contact fatigue life of bearings is highly sensitive to the uniformity of the steel's microstructure. Improving steel cleanliness by reducing impurities and inclusions, and ensuring fine, uniform distribution of non-metallic inclusions and carbides, significantly enhances the fatigue life of bearing steel. The ideal microstructure consists of fine carbide particles evenly distributed in a tempered martensite matrix. Controlled rolling and controlled cooling have become essential in producing high-quality bearing steel. These techniques help eliminate reticulated carbides and obtain suitable microstructures. Low-temperature controlled rolling (800–850°C) followed by air cooling and short-time annealing, or even skipping the spheroidizing annealing step, has been successfully applied in countries like Russia and Japan. Temperature processing at 650°C is another emerging technique. When eutectoid or high-carbon steels are processed under specific conditions, they can exhibit superplasticity, enabling easier forming and improved material properties. This method reduces energy consumption and simplifies production. In heat treatment, efforts have focused on improving the quality of spheroidizing annealing, achieving finer and more uniform carbide distributions while reducing annealing time or eliminating the process altogether. Continuous spheroidizing annealing is now considered a key direction for future development. New bearing steel grades are being developed to replace traditional ones, such as fast-carburizing steels with improved carburizing speeds and shorter times. High-frequency hardened bearing steels made from medium carbon steels also offer cost savings and longer service life. In Japan, GCr465 and SCM465 have shown fatigue life improvements of 2–4 times compared to SUJ2. For extreme environments, high-temperature and corrosion-resistant bearing steels like M50NiL and 50X18M are being researched. Ceramic bearing materials are also gaining traction due to their superior performance in harsh conditions. China has developed high-hardenability bearing steels like GCr15SiMo, which offers better fatigue life and impact resistance compared to GCr15SiMn. Another innovation is GCr4, which improves impact value and crack resistance, making it suitable for heavy-duty, high-speed train bearings. Looking ahead, bearing steel will continue to evolve toward higher cleanliness and functional diversification. Reducing oxygen content to as low as 5 ppm can extend bearing life by an order of magnitude. Future developments will focus on meeting diverse environmental demands, such as quasi-high-temperature, corrosion-resistant, and high-frequency hardened bearing steels, as well as high-temperature applications in aerospace. **Related Articles** - Common Repair Methods for Bearings - How to Protect SKF Bearings - The Advancement of Bearing Technology - Operating Principle of Oil Film Bearings **Recommended for Friends** Comments | Close Window This article is sourced from China Bearing Network: http://www.chinabearing.net Previous: Correct Application of Grease Next: Disposal of Excessive Bearing Temperature

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