High-temperature bearing steel
High-temperature bearing steel
Typically, the operating temperature above 150 ℃ in the bearings as the use of high-temperature bearings. Chromium bearing steel as a result of the use temperature exceeds 150 ℃ ~ C, the hardness of the sharp decline in the size of instability and lead to bearing not work correctly. Therefore, the working temperature of 150 ℃ ~ E ~ 250 ℃ under the conditions of the work of bearing, if the ferrule and the ball still use an ordinary high-carbon chromium bearing steel manufacturing, must be parts of the bearing special tempering treatment, the general should be higher than temperature tempering under 50 ℃. After tempering to deal with these requirements in accordance with the bearing steel, able to work under the normal use temperature. However, a decrease of hardness after tempering, the bearings have lower life expectancy. When the bearing operating temperature is higher than 250 ℃, it must be high temperature resistant steel bearings.
In addition to high-temperature bearing steel bearing steel with the performance of the general should have some 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 in high-temperature bearing steel are:
Molybdenum steel: Cr4M04V, Crl5M04, 9Crl8Mo, Crl4M04;
Tungsten steel grades: W9Cr4V2Mo, W18Cr4V;
Department of W-Mo: W6MoSCr4V2.
High-temperature bearing steel W, Cr, V, Mo, etc. can form insoluble carbide under high temperature and precipitation in tempering can diffuse distribution of carbides, resulting in secondary hardening effect, so that this type of steel under certain temperature is still more high hardness, wear resistance, strong anti-oxidation performance, a higher fatigue resistance and dimensional stability. High-temperature bearing steel of which the most commonly used Cr4M04V and W18Cr4V.
The complex structure, but also need to bear the strong impact of load bearing, to be used in high temperature carburizing steel. 12Cr2Ni3M05 better performance is a high-temperature carburizing bearing steel, because of its low carbon content (0.15% or so), there is no disadvantage of uneven carbide, annealing of low hardness, good cutting performance with high toughness can be forging good bearings to increase than forging parts, bearing in favor of life, can meet the carburizing temperature of 430 ~ C the following conditions of use and has good impact resistance capacity.
H10Cr4M04Ni4VA is the best performance of the high-temperature carburizing bearing steel, but its price is rather expensive. When the bearing temperature exceeds the use of 500 ~ E, the selection of high temperature bearing steel has been difficult to meet their performance requirements, and should use cobalt-based, nickel-based alloys or ceramic materials such as high temperature.
The main bearings for high-temperature air jet engines and gas turbines, nuclear reactor systems, X-ray tube tungsten plate, and high-speed aircraft, rockets, spacecraft in.
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Author：mosbearing 2009-7-13 Source: View(949) Comment(0)