High temperature bearing steel

Generally, bearings whose operating temperature is above 150°C are called high-temperature bearings, and these bearings need to be made of high-temperature resistant steel materials. As the chromium bearing steel is used at a temperature exceeding 150℃~C, its hardness will drop sharply, the size will be unstable, and the bearing will not work normally. Therefore, for bearings whose working temperature is 150℃~E～250℃, if the rings and rolling elements are still made of ordinary high-carbon chromium bearing steel, the bearing parts must be subjected to special tempering treatment, which should generally be high Tempering is performed at a working temperature of 50°C. The bearing steel that has been tempered according to the above requirements can be used normally at a working temperature of 250°C. However, due to the decrease in hardness after tempering, the life of the bearing is reduced. When the bearing operating temperature is higher than 250°C, it must be made of high-temperature bearing steel.

In addition to the properties of general bearing steels, high-temperature bearing steels also have certain high-temperature hardness and 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 series steel: Cr4M04V, Crl5M04, 9Crl8Mo, Crl4M04;

Tungsten steel: W9Cr4V2Mo, W18Cr4V;

Tungsten and molybdenum series: W6MoSCr4V2.

Elements such as W, Cr, V, Mo in high temperature bearing steel can form carbides that are insoluble at high temperatures, and precipitate dispersed carbides during tempering, resulting in a secondary hardening effect, so that this type of steel still has a certain temperature Higher hardness, wear resistance, stronger oxidation resistance, higher fatigue resistance and dimensional stability. Among them, Cr4M04V and W18Cr4V are the most commonly used in high temperature bearing steels

For bearings that are complex in structure and need to withstand strong impact loads, they can be made of high-temperature carburized steel. 12Cr2Ni3M05 is a high-temperature carburized bearing steel with good performance. Because of its low carbon content (about 0.15%), there is no defect of uneven carbides, low annealing hardness, good cutting performance, high toughness. , and good forgeability, can increase the forging pressure ratio of bearing parts, and is beneficial to the service life of the bearing. After carburizing, it can meet the conditions of use below 430~C, and has good impact resistance.

H10Cr4M04Ni4VA is currently the best high-temperature carburized bearing steel, and its price is relatively expensive. When the service temperature of the bearing exceeds 500~E, the selection of high-temperature bearing steel is difficult to meet its performance requirements, and high-temperature 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 disks, and high-speed aircraft, rockets, and spacecraft