Crack analysis of case-hardened 20Cr2Ni4 steel gear after assembly

doi:10.13251/j.issn.0254-6051.2021.08.048

Abstract

Abstract: Failure reason of the case-hardened 20Cr2Ni4 steel gear after assembly was analyzed by means of OM, micro-hardness tester and spectrometer. The results show that the tooth top hardness and hardened case depth of the carburized and hardened gear all meet the requirements and the microstructure is good. The cracks source is at the weight-reducing hole of spoke, and the rough tool marks obviously formed in the inner wall of weight-reducing hole can lead to the stress concentration, resulting in the cracks of gear and axle after assembly expanding to the inner hole of gear gradually. And then the fracture failure is occurred, finally some improvement measures are put forward.

Key words: gear, 20Cr2Ni4 steel, carburizing and quenching, weight-reducing hole, rough tool mark, crack source

CLC Number:

TG156.8

Xu Hongxiang, Wang Hongwei, Zhang Heng, Wang Jun, Zhao Shaofu. Crack analysis of case-hardened 20Cr2Ni4 steel gear after assembly[J]. Heat Treatment of Metals, 2021, 46(8): 250-253.

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Crack analysis of case-hardened 20Cr2Ni4 steel gear after assembly

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