Cracking failure analysis of 40Cr steel forgings for automobile front axle

doi:10.13251/j.issn.0254-6051.2021.12.049

Abstract

Abstract: Cracking reason of 40Cr steel forgings used for automobile front axle was analyzed by means of chemical composition, microstructure and hardness analysis. The results show that the crack is a quenching crack occurred at the R angle of the forgings. The elemental segregation at the R angle of the forgings results in significantly higher hardenability than that of other locations around. Surface defects are produced in the forging process, so that the volume stress generated by martensitic transformation during quenching exceeds the strength of the material, resulting in the generation of quenching cracks. By increasing the R angle radius, controlling the chemical segregation of raw materials and adjusting the forging process, the risk of quenching cracking of 40Cr steel forgings for automobile front axle after heat treatment can be reduced.

Key words: 40Cr steel, automotive front axle, quenching crack, elemental segregation

CLC Number:

TG157.35

Cheng Yuan, Hu Fangzhong, Yang Shaopeng, Wang Kaizhong, Jin Guozhong, Chen Shijie, Wang Lianglin. Cracking failure analysis of 40Cr steel forgings for automobile front axle[J]. Heat Treatment of Metals, 2021, 46(12): 294-297.

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