Usually, the working temperature above 150 ℃ using bearing called high temperature bearing.
Due to chromium bearing steel in the use of temperature exceeds 150 ℃ ~ C, its will be a sharp drop in hardness, size is not stable, and causes the bearing cannot work normally.
So for the working temperature at 150 ℃ ~ E ~ 250 ℃ under the working conditions of the bearings, if the ring and rolling body still choose ordinary high carbon chromium bearing steel manufacturing, it must be special tempering treatment was carried out on the bearing parts, the general should be higher than under the working temperature of 50 ℃ tempering.
After tempering treatment according to the requirements of the bearing steel, can be used in normal working temperature.
But after tempering hardness decreased, bearing life.
When the bearing temperature higher than 250 ℃, must use high temperature resistant bearing steel manufacturing.
High temperature bearing steel besides should have general bearing steel performance, should also have a certain high temperature hardness and high temperature wear resistance, high temperature and contact fatigue strength, oxidation resistance, heat shock resistance and high temperature dimensional stability.
The commonly used high temperature bearing steel are: molybdenum steel: Cr4M04V, Crl5M04, 9 crl8mo, Crl4M04;
Tungsten steel: W9Cr4V2Mo, W18Cr4V;
Tungsten molybdenum: W6MoSCr4V2.
High temperature bearing steel W, Cr, V, Mo and so on can form of undissolved carbide under high temperature, and can precipitate are dispersed carbides during tempering, produce the secondary hardening effect, make this kind of steel under a certain temperature still has high hardness, wear resistance, strong oxidation resistance, high fatigue resistance and dimensional stability.
High temperature bearing steel with Cr4M04V and W18Cr4V is most commonly used.
For complex structure, but also bear strong impact load bearing, can use high temperature carburizing steel manufacturing.
12 cr2ni3m05 is a kind of performance better high temperature carburizing bearing steel, because of its low carbon content (
0.
About 15%)
, there is no uneven carbide shortcomings, annealing hardness is low, cutting performance is good, has the high toughness and good malleability and can increase the bearing parts of the forging ratio, is beneficial to the service life of bearing, after carburizing can meet under the temperature 430 ~ C conditions of use, and has the very good impact resistance.
H10Cr4M04Ni4VA is currently the best performance of high temperature carburizing bearing steel, but its price is more expensive.
When the bearing temperature more than 500 ~ E, using high temperature resistant bearing steel has been difficult to meet the performance requirements, and should choose cobalt base, such as resistance to high temperature nickel base alloy or ceramic materials.
High temperature bearing is mainly used for air jet engines, gas turbine, the nuclear reactor system, the X-ray tube tungsten plate, and high-speed aircraft, rocket, the spacecraft.
