CAS NO: 4050-45-7,Molecular Formula: C6H12,CAS NO: 65886-91-1,Molecular Formula: C9H9Cl,CAS NO: 250337-98-5,Molecular Formula: C9H9Br,CAS NO: 250337-98-5 Chemtarget Technologies Co., Ltd. , https://www.dgtbcb.com
Bearing steel new technology and direction
Bearing steel is primarily used in the manufacturing of rolling elements and races for bearings. To ensure long service life, high precision, low heat generation, high-speed operation, high rigidity, minimal noise, and excellent wear resistance, bearing steel must possess specific properties such as high hardness, uniform hardness, high elastic limit, superior contact fatigue strength, adequate toughness, proper hardenability, and corrosion resistance in lubricants. These requirements necessitate strict control over the chemical composition, non-metallic inclusions, carbide size and distribution, and decarburization levels.
Over time, bearing steels have evolved toward higher quality, better performance, and a wider range of applications. They are categorized into types such as high-carbon chromium bearing steel, case-hardened bearing steel, high-temperature bearing steel, stainless bearing steel, and special-purpose materials based on their characteristics and usage environments. To meet modern demands like high temperature, high speed, heavy load, corrosion resistance, and radiation tolerance, new specialized bearing steels have been developed.
To reduce oxygen content and improve purity, advanced smelting techniques like vacuum arc remelting, electroslag remelting, and electron beam remelting have been introduced. Large-scale production now uses electric arc furnaces combined with primary refining processes, enhancing efficiency and quality. Modern production involves primary furnace + LF/VD or RH + continuous casting + continuous rolling, ensuring high-quality output with low energy consumption.
Heat treatment has also advanced, with continuous controlled atmosphere annealing furnaces replacing traditional methods. These furnaces can be up to 150 meters long, offering stable spheroidized structures, minimal decarburization, and reduced energy use. The focus remains on achieving a uniform fine carbide structure in a tempered martensite matrix, which is essential for optimal performance.
Since the 1970s, industrial growth and international trade have driven the standardization and adoption of new technologies in bearing steel. Countries like Japan and Germany have established high-purity production lines, significantly improving steel quality and fatigue life. Japanese and Swedish bearing steels now have oxygen content below 10 ppm, with some reaching as low as 5.4 ppm.
Improving cleanliness by reducing impurities and inclusions enhances contact fatigue life. Controlling carbide distribution through processes like controlled rolling and cooling helps achieve finer microstructures and longer bearing life. Low-temperature controlled rolling (below 850°C) and advanced heat treatments, such as 650°C processing, have also been explored to simplify production and enhance performance.
In terms of heat treatment, progress has been made in achieving finer, more uniform carbides while reducing or eliminating spheroidizing annealing. This has increased furnace efficiency by 25–30%. Continuous spheroidizing annealing is becoming the future direction for bearing steel processing.
New bearing steels are being developed to replace traditional grades. Fast carburizing steels, for example, increase carburizing speed and reduce processing time. High-frequency quenching steels offer cost-effective alternatives with improved service life. In Japan, GCr465 and SCM465 show 2–4 times the fatigue life of SUJ-2, while M50 and 440C are being replaced by newer materials like M50NiL and 50X18M.
China has also developed advanced bearing steels like GCr15SiMo, which offers higher hardenability and significantly improved contact fatigue life compared to GCr15SiMn. GCr4 steel, designed for energy savings and impact resistance, shows a 66–104% increase in impact value and a 12% improvement in L10 life.
Looking ahead, bearing steel will continue to evolve in two main directions: higher cleanliness and diversified performance. Reducing oxygen content from 28 ppm to 5 ppm can extend bearing life by an order of magnitude. As application environments become more demanding, new bearing steels must address challenges like high temperature, corrosion, and process simplification. Future developments will focus on creating versatile, durable, and cost-effective materials suitable for aerospace, automotive, and other high-performance industries.