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Shanghai Shang Shaft Bearing Quality Inspection Institute Co., Ltd.

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(II) on Dimensional Stability of Rolling Bearings

2021-04-28 14:12

2.4 Domestic rightCr4Mo4Vstudy of steel

Domestic rightCr4Mo4VSteel200Dimensional stability after high temperature tempering for hours3.

FigureCr4Mo4VSteel200Dimensional stability after high temperature tempering in hours

By1000See Table for dimensional changes after high temperature tempering in hours.2。

T/℃

204

316

427

532

Dimensional change/(10-6mm/mm)

22

12

27

-50

TableCr4Mo4VSteel1000Dimensional change after high temperature tempering in hours

2.5 Other Methods

Some domestic scholars are studyingGCr15The residual austenite and grinding stress of the bearing ring are used in100~170The dimensional stability of the ferrule is measured by long-term artificial aging between degrees C and the amount of dimensional change is observed.

Discussion

3.1 Clear whether there is"Poor dimensional stability" problem

Many domestic bearing manufacturers react"The dimensional stability of domestic bearings is poor", but it is impossible to provide relevant test data to prove its gap. In fact, most of the failed bearings have not reached the design life, and the reasons for the damage are poor lubrication, fatigue, pollution, improper installation and use. When the bearing fails, the cause of the failure should be analyzed first. For the failure caused by non-manufacturing factors, it is not necessary to mix the problem of "dimensional stability. When the dimensional stability of the product is questioned, the product should be tested and verified, especially in the process of product imitation, more attention should be paid to the use of data to reflect the gap.

3.2 System Problems of Dimensional Stability

The dimensional stability of the bearing is aimed"Bearing" is not a simple metal material or heat treatment problem, but a system problem, should consider the structural design, manufacturing, application and each bearing component in the bearing service process on the size change. Problems such as large performance differences between batches or single pieces should not be discussed in the scope of "dimensional stability". Methods to improve product "consistency" and "stability" should be based on the stability of production equipment, processing quality consistency, personnel skill level, personnel stability, production process control means, material uniformity and accuracy of measurement system.

3.3 Choosing the appropriate evaluation method

The method of evaluating dimensional stability at home and abroad described in this paper is not applicable to all bearings, and there are certain limitations. Readers can use this as a reference or explore the evaluation methods suitable for their own products, and summarize the technical requirements suitable for specific models of products. For example, the evaluation method of the ring described in this paper has the problem of long test cycle, a foreign company on this basis to explore and develop a more simple and fast test method, and put forward specific technical requirements for different models of products. In addition, it is recommended that the relevant departments develop testing standards as soon as possible to provide an agreement basis for bearing manufacturers and users.

References

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 Zhang Lifeng, etc..Non-metallic inclusions and element segregation in bearing steel[M].Beijing:Metallurgical Industry Press,2017.

 Li Aimin, etc..Effect of Final Grinding Process on Dimensional Stability of Bearing Rings[J].Bearing,2009,12(1):17-19.

 Zhou LeiInfluencing Factors of Dimensional Stability of. PA6 Material[J].Plastic,2019,48(4):72-76.

 GB/T36222General specification for deep groove ball bearing for aero motor[S].Beijing:China Standard Press,2018.

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 Yan Minggao, etc..China Aviation Material Manual No.2Edition No.1coil structural steel stainless steel[M].Beijing:China Standard Press,2001.