Thermal fatigue evaluation of AISI H13 steels surface modified by gas nitriding with pre- and post-shot peening
作者:    发表时间: 2019-04-02   阅读次数: 821次

Thermal fatigue evaluation of AISI H13 steels surface modified by gas
nitriding with pre- and post-shot peening

Bin Liu, Bo Wang, Xudong Yang, Xingfeng Zhao, Ming Qin, Jianfeng Gu

 

Keywords: Hot work die steel, Gas nitriding, Shot peening, Thermal fatigue, Thermal cracking

 

Abstract:    In this work, the H13 hot work die steels were surface modified and experimentally evaluated in a homemade thermal fatigue simulation tester. Two types of nitrided compound layers, and compound-free layers with and without surface deformation were prepared by a selection of surface modifications including traditional gas nitriding, controlled gas nitriding, gas nitriding with pre-shot peening, and controlled gas nitriding with postshot peening. Thermal cracks formed in the nitrided compound layer propagated faster on surface but slower along the depth direction as compared to those in the compound-free layer. Thermal crack advancing along the depth direction in the sample nitrided with pre-shot peening had a tendency to be suppressed by the higher cross-sectional hardness distribution. The deformed compound-free nitrided layer showed the excellent thermal fatigue cracking resistance in both surface and cross-section, which was attributed to the good combination of hardness and toughness, as well as the underlying enhanced compressive residual stress.

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