The inner and outer rings and rolling bodies of rolling bearings should have high hardness, contact fatigue strength, good wear resistance and impact toughness. They are generally made of chromium manganese high carbon steel (pitting corrosion resistance), and the commonly used materials are GCr15 bearing steel, GCr15SiMn bearing steel, GCr6 bearing steel, GCr9 bearing steel, etc. After quenching, the hardness is not less than 61HRC-65HRC.
According to the understanding of the following China bearing network, it summarizes the performance of various commonly used materials of rolling bearings, bearing steel, which mainly include the following:
GCr15 bearing steel
GCr15 bearing steel is a kind of 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, general cutting performance, poor welding performance, high sensitivity to the formation of white spots, and tempering brittleness.GCr15 bearing steel, containing C0.95-1.05, Mn0.25-0.45, Si0.15-0.35.
Good overall performance. Good cutting performance after spheroidizing annealing.After quenching and tempering, the hardness is high and uniform, wear resistance and contact fatigue strength is high.Hot working performance is good. Contain less alloy elements, the price is cheaper.
GCr15SiMn bearing steel
GCr15SiMn bearing steel has higher wear resistance and hardenability than GCr15, medium plastic deformation in cold processing, poor weldability, sensitive to white spot formation, and temper brittleness during heat treatment.Used for manufacturing wall thickness >12mm. Rings with outer diameter ≥250mm;Diameter 50.8-203.2 steel ball, diameter >;22mm roller;In addition, it can also be used for other mechanical parts requiring high hardness and high wear resistance, such as rollers.Screw gauges, etc.
GCr15SiMn steel is high carbon and high chromium bearing steel, which has higher wear resistance and hardenability than GCr15 steel.The critical quenching diameter in the oil is 90~110mm (volume fraction is 50% martensite), after 840°C oil cold quenching,350°C tempering state, and then light quenching, surface hardness up to 1096HV, the depth of hardened layer up to 1mm.In view of the deficiency of heat treatment process of forming roller, non-martensite transformation is produced by precooling at thin edge to produce tortensite or sorbite, which can enhance toughness, reduce stress, and then quench as a whole to meet the process requirements.
Cold treatment can improve the dimensional stability of bearings, or martensite grading quenching, to stabilize the residual austenite, obtain high dimensional stability and high toughness.Forging of this steel is generally not recommended.Generally used after quenching and low temperature tempering.
GCr6 bearing steel
GCr6 bearing steel is used for measuring 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 that of carbon tool steel, and the size changes are not large during heat treatment.Widely used in measuring tools, such as templates, clamps, sample sleeves, gauges, block gauges, ring gauges, threaded plug gauges and sample columns, etc., can also be used in the manufacture of wire drawing die and cold heading die and other cold die, and low speed cutting tools to cut not too hard materials.
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 the formation of white spot is also sensitive, and the heat treatment has the tendency of tempering brittleness.Used to manufacture steel balls with diameters of 13.5-25.4mm, tapered rollers with diameters of 10.3-18.5mm, cylindrical rollers with diameters of 9.4-17.2 and spherical rollers with diameters of 9.2-17.1.
GCr9 steel is a kind of high carbon chromium bearing steel with less alloy content, good properties and most widely used.After quenching and tempering, it has higher hardness, uniform structure, good wear resistance and high contact fatigue performance.The steel has moderate cold working plasticity, general cutting performance, poor welding performance, high sensitivity to the formation of white spots, and tempering brittleness.
Mainly used in the production of internal combustion engines, electric locomotives, automobiles, tractors, machine tools, rolling mills, drilling machines, mining machinery, general machinery, as well as high-speed rotation of a high load mechanical transmission bearing ball, roller and ring.In addition to making ball, bearing rings, sometimes also used to make tools, such as die, measuring tools.