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对C250型18%Ni超高强度钢(C250钢)进行铸钢丸一次喷丸(单喷)和铸钢丸+玻璃丸二次喷丸(双喷),研究喷丸前后的表面形貌、显微组织和低周疲劳性能的变化.结果表明,单喷后C250钢低周疲劳寿命提高了接近2.5倍,而双喷后试样疲劳寿命提高3倍.喷丸表面的亚晶粒细化是提高低周疲劳性能的主要因素,二次喷丸带来的平滑化效果进一步提高了低周疲劳性能.平滑化效果减小了表面应力集中程度,使经过双喷后试样疲劳断口为单源疲劳断口,而未喷丸试样和单喷试样的低周疲劳断口呈现多源疲劳状态.
The surface morphology of the C250 18% Ni ultrahigh strength steel (C250 steel) shot blasting shot blasting (single shot) and cast steel shot + glass shot secondary shot blasting (double shot blasting) The results show that the low cycle fatigue life of C250 steel after single injection is increased by nearly 2.5 times and the fatigue life of sample after double injection is increased by 3 times.The subgrain refinement Is to improve the low cycle fatigue performance of the main factors, the second shot peening to bring the smoothing effect to further improve the low cycle fatigue performance.Smoothing effect reduces the surface stress concentration, so that after double-jet sample fatigue fracture as a single Source fatigue fracture, but not shot peening specimens and single low-cycle fatigue fracture showed multi-source fatigue state.