The inner and outer rings and rolling elements of rolling bearings should have high hardness and contact fatigue strength, good wear resistance and impact toughness, and are generally made of chromium-manganese high-carbon steel (pitting resistance), and commonly used materials are GCr15 bearing steel, GCr15SiMn bearings Steel, GCr6 bearing steel, GCr9 bearing steel, etc., the hardness after quenching is not less than 61HRC-65HRC. Bearing steel Based on the understanding, the following summarizes the performance of bearing steel of various materials commonly used in rolling bearings, mainly in the following categories: GCr15 bearing steel GCr15 bearing steel is a high-carbon chromium bearing steel with less alloy content, good performance and the most widely used. After quenching and tempering, it has high and uniform hardness, good wear resistance and high contact fatigue performance. The steel has moderate cold working plasticity, average cutting performance, poor welding performance, high sensitivity to white spots, and temper brittleness. GCr15 bearing steel, containing c0.95-1.05, Mn0.25-0.45, Si0.15-0.35. Good comprehensive performance. After spheroidizing annealing, it has good cutting performance. After quenching and tempering, it has high and uniform hardness, high wear resistance and contact fatigue strength. It has good thermal processing performance. It contains less alloy elements and is cheaper. GCr15SiMn bearing steel GCr15SiMn bearing steel has higher wear resistance and hardenability than GCr15, moderate plastic deformation during cold working, poor weldability, sensitive to white spot formation, and temper brittleness during heat treatment. Used to manufacture rings with wall thickness > 12mm and outer diameter ≥ 250mm; steel balls with a diameter of 50.8-203.2mm, rollers with a diameter > 22mm; in addition, it can also be used as other mechanical parts that require high hardness and high wear resistance, such as rolls. Spiral gauges, etc. GCr15SiMn steel is a high-carbon, high-chromium bearing steel, which has higher wear resistance and hardenability than GCr15 steel. The critical quenching diameter in oil is 90~110mm (volume fraction is 50% martensite). After 840°C oil cooling quenching, 350°C tempering state, and then light quenching, the surface hardness is as high as 1096HV, and the depth of the hardened layer can reach 1mm. In view of the lack of heat treatment process of the forming roller, pre-cooling at the thin edge is used to produce non-martensitic transformation, and Trostite or sorbite is produced to enhance toughness, reduce stress, and then overall quench to meet the process requirements. Ice cooling treatment can improve the dimensional stability of the bearing, or martensitic quenching can be carried out to stabilize the retained austenite and obtain high dimensional stability and high toughness. This steel is generally not recommended for forging. Generally used after quenching and low temperature tempering. GCr6 bearing steel GCr6 bearing steel is used for measuring tools and cutting tools. The composition of this steel is similar to that of GCr6 bearing steel. Its hardenability, hardness and wear resistance are higher than those of carbon tool steel, and its size does not change much during heat treatment. Widely used as measuring tools, such as templates, pallets, sample sets, gauges, block gauges, ring gauges, thread plug gauges and sample columns, etc., can also be used to manufacture cold working dies such as wire drawing dies and cold heading dies, and low-speed tool cutting without too hard material. GCr9 bearing steel The wear resistance and hardenability are higher than GCr6 steel, the machinability is acceptable, the cold strain plasticity is medium, the weldability is poor, and it is also sensitive to the formation of white spots, and the heat treatment has a tendency to temper brittleness. It is used to manufacture steel balls with a diameter of 13.5-25.4mm, tapered rollers with a diameter of 10.3-18.5mm, cylindrical rollers with a diameter of 9.4-17.2 and spherical rollers with a diameter of 9.2-17.1. GCr9 steel is a high-carbon chromium bearing steel with less alloy content, good performance and the most widely used. After quenching and tempering, it has high hardness, uniform structure, good wear resistance and high contact fatigue performance. The steel has moderate cold working plasticity, average cutting performance, poor welding performance, high sensitivity to white spots, and temper brittleness. It is mainly used to make steel balls, rollers and rings of internal combustion engines, electric locomotives, automobiles, tractors, machine tools, rolling mills, drilling machines, mining machinery, general machinery, and high-load mechanical transmission bearings that rotate at high speed. In addition to making balls, bearing rings, etc., it is sometimes used to make tools, such as dies and measuring tools.  

We have rich experience on precision bearing manufacturing and are ranked NO.1 in China and NO.3 all over the world.

We can tailor the overall solution for the use of precision bearings.

HONB– Accountability & Innovation