Heat Treatment of Metals ›› 2024, Vol. 49 ›› Issue (4): 257-263.DOI: 10.13251/j.issn.0254-6051.2024.04.041

• SURFACE ENGINEERING • Previous Articles     Next Articles

Fatigue crack propagation properties of industrial pure iron intensified by high energy shot peening

Liu Rongwei, Huang Zhiguo, Liu Xiangyu, Sun Yangfeng, Wei Yandong, Cui Xihe, Hou Helong, Xu Lindong   

  1. Industrial Technology Center, Hebei Petroleum University of Technology, Chengde Hebei 067000, China
  • Received:2023-11-06 Revised:2024-03-11 Online:2024-04-25 Published:2024-05-27

Abstract: High-energy shot peening was adopted to form self-nanocrystallization layer on the surface of industrial pure iron, and its effects on fatigue crack propagation rate, microstructure, microhardness and fatigue fracture morphology of the base metal were comparatively analyzed by fatigue crack propagation test. The results show that high-energy shot peening has a significant inhibitory effect on initiation and propagation of the fatigue crack when the stress intensity factor is lower than 50 MPa·m1/2, but it is not obvious for that higher than 50 MPa·m1/2. After high-energy shot peening, the grains on surface structure of the specimen are seriously extruded and fragmented, and the surface hardness is about 40% higher than that of the base metal, while the hardness decreases rapidly with the increase of the depth from surface. The maximum effect depth of high-energy shot peening reaches 3.88×10-4 mm. From the surface to the inside of the shot peening specimen, it can be divided into surface damage zone, nano layer, severe grain deformation zone, grain deformation zone and unaffected zone, and there is no obvious boundary between different zones.

Key words: industrial pure iron DT4C, high-energy shot peening, fatigue crack propagation, microstructure, fatigue fracture

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