High Temperature Bearing Steel

Generally, bearings used at temperatures above 150°C are called high-temperature bearings. Because the hardness of chromium bearing steel will drop sharply when the temperature exceeds 150℃~C, the size will be unstable, and the bearing will not work normally. Therefore, for bearings that work at a working temperature of 150 ° C ~ E ~ 250 ° C, if the rings and rolling elements are still made of ordinary high-carbon chromium bearing steel, special tempering treatment must be carried out on the bearing parts, generally higher than Tempering is carried out at a working temperature of 50°C. The bearing steel that has been tempered according to the above requirements can be used normally at the working temperature. However, due to the decrease in hardness after tempering, the bearing life is reduced. When the working temperature of the bearing is higher than 250°C, it must be made of high temperature resistant bearing steel.
In addition to the properties of general bearing steel, high-temperature bearing steel should also have certain high-temperature hardness, high-temperature wear resistance, high-temperature contact fatigue strength, oxidation resistance, high-temperature impact resistance and high-temperature dimensional stability. Commonly used high temperature bearing steels are:
Molybdenum steel: Cr4M04V, Crl5M04, 9Crl8Mo, Crl4M04;
Tungsten steel: W9Cr4V2Mo, W18Cr4V;
Tungsten and molybdenum series: W6MoSCr4V2.High-temperature bearing steels W, Cr, V, Mo, etc. can form insoluble carbides at high temperatures, and can precipitate dispersed carbides during tempering, resulting in a secondary hardening effect, making this type of steel still have a relatively high temperature at a certain temperature. High hardness, wear resistance, strong oxidation resistance, high fatigue resistance and dimensional stability. Among the high temperature bearing steels, Cr4M04V and W18Cr4V are the most commonly used.
For bearings with complex structures and strong impact loads, they can be made of high-temperature carburized steel. 12Cr2Ni3M05 is a high-temperature carburized bearing steel with better performance. Because of its low carbon content (about 0.15%), there is no defect of uneven carbides, low annealing hardness, good cutting performance, and high toughness. Good forgeability can increase the forging ratio of bearing parts, which is beneficial to the service life of the bearing. After carburizing, it can meet the service conditions at a temperature below 430~C, and has good impact resistance.
H10Cr4M04Ni4VA is currently the best high-temperature carburized bearing steel, but its price is relatively expensive. When the service temperature of the bearing exceeds 500~E, it is difficult to meet the performance requirements of high-temperature-resistant bearing steel, and high-temperature-resistant materials such as cobalt-based, nickel-based alloys or ceramics should be used.
High-temperature bearings are mainly used in aviation jet engines, gas turbines, nuclear reactor systems, X-ray tube tungsten discs, and high-speed aircraft, rockets, and spacecraft.