Heat treatment process of GCr15 steel bearing ring

Abstract

The invention provides a heat treatment process of a GCr15 steel bearing ring, comprising the following steps of: (1) heating a bearing to 830 DEG C-860 DEG C and keeping the temperature; (2) quenching in oil; and (3) tempering and keeping the temperature. By adopting the selection of the tempering temperature and the temperature keeping time and the control of carbon potential, the invention ensures that under the condition of quasi high-temperature tempering, at the working temperature of 160 DEG C, the size variation of an inner-ring roller path and an outer-ring roller path of the heat-treated GCr15 steel bearing ring is not more than 0.008 mm, and the hardness is not less than 57HRC and is more than that of a high-temperature tempered GCr15 steel bearing ring. Meanwhile, the heat treatment process is simple and has lower cost compared with the traditional low-temperature treatment and high-temperature tempering process.

Description

technical field [0001] The invention relates to the field of heat treatment technology, in particular to the heat treatment technology of GCr15 steel bearing rings. Background technique [0002] The working temperature of ordinary GCr15 steel bearings is below 150°C, and the bearings used at working temperatures above 150°C are called high-temperature bearings. After normal quenching and tempering of GCr15 steel bearing rings, when the operating temperature exceeds 150°C, the hardness will drop sharply, the size will be unstable, and the bearing will not work normally. This is because the content of retained austenite in the structure of GCr15 steel bearing ring after conventional martensitic quenching is generally 6% to 15%. Retained austenite is a soft metastable phase. Under certain conditions (such as tempering, natural aging or the use of parts), its instability occurs and decomposes into martensite or bainite. The consequence of decomposition is that the hardness of ...

AI Technical Summary

Problems solved by technology

First of all, cryogenic treatment can eliminate residual austenite and increase dimensional stability, but since the twin martensite formed after cryogenic treatment is a hard and brittle phase, its impact resistance is poor, so bearings after cryogenic treatment are prone to brittleness. fracture failure

Especially it is difficult to be applied under the condition of certain impact load

Moreover, the capacity of cold treatment equipment is limited, and most of them are periodic operation equipment, which is difficult to meet the needs of mass production

To achieve a good cold treatment effect, usually need to use dry ice or liquid nitrogen, high production cost

Secondly, the conventional heat treatment process of increasing the tempering temperature to eliminate residual austenite usually leads to a reduction in the hardness of the bearing parts, which will cause the wear resistance of the bearing parts to deteriorate and shorten the service life

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