Improving tension fatigue performance of gray cast iron by LSPwC-induced gradient structure and carbon diffusion

HT250 Gray cast iron (GCI) commonly utilized in diesel engine cylinders, is susceptible to fatigue failure under alternating stress conditions. To address this issue, the investigation involved the application of laser shock peening without coating (LSPwC) on HT250 GCI to assess its impact on the high cycle tension fatigue properties of the material. Both experimental and simulation methodologies were employed to analyze the effects of LSPwC on residual stress, microhardness, and microstructure in HT250 GCI. The LSPwC resulted in a substantial 29% enhancement in the high cycle tension fatigue limit of the HT250 GCI, which is attributed to a synergistic combination of factors induced by LSPwC, including high-amplitude compressive residual stresses, elevated microhardness, grain refinement, and carbon diffusion. This study contributes valuable insights into the reinforcement of complex cast components.