为了研究基于机械喷丸(SP)、热定型工艺的激光冲击处理(LSP) 对气门弹簧性能影响, 利用高功率激光对不同加工工艺制造的气门弹簧内侧进行单点冲击处理, 从残余应力、显微硬度和微观组织等方面分析了激光冲击强化对气门弹簧的影响。结果表明, 弹簧的激光冲击强化与喷丸强化相比, 效果差距不大。对基于喷丸强化的气门弹簧激光冲击处理的强化效果明显, 二次喷丸下的激光冲击处理出现最大残余压应力, 达到-541 MPa, 经二次喷丸+热定型处理的弹簧表面显微硬度最大, 达到668.4 HV。不同制造工艺制造的弹簧激光冲击强化后表面显微硬度的变化规律与冲击前基本一致。弹簧经激光冲击强化后晶粒发生细化, 晶粒尺寸和强化相是提高硬度的主要原因。

In order to study the effect of laser shock processing (LSP) on valve spring based on shot peening (SP) and heat setting, the valve spring manufactured by different processes were treated by LSP with high power Nd∶YAG laser. The effects of valve spring on mechanical properties after LSP were analyzed from residual stress, micro-hardness and microstructure. The results indicate that the effect on valve spring after LSP is similar to that after SP. The strengthening effect of valve spring by LSP based on SP is obvious. After LSP, the residual stress of valve spring based on shot peening twice reaches maximum value -541MPa and the micro-hardness of valve spring surface based on shot peening twice and heat setting reaches maximum value 668.4 HV. The variation of micro-hardness on valve spring surfaces manufactured by different processes after LSP is mostly identical to that before LSP. The grain refinement occurs after LSP and the primary cause of improving micro-hardness is grain size and strengthening phase.