搭接次数对40Cr钢激光冲击残余应力分布的影响

Effects of Overlapping Times on Distribution of Laser Shock Residual Stress for 40Cr Steel

利用Nd：YAG激光器对40Cr表面进行不同光斑搭接率的激光冲击强化处理。采用XRD-350A型X射线衍射仪对冲击后表面不同搭接区域的残余应力进行分析。结果表明：激光冲击后的表面残余压应力明显大于未冲击的表面残余压应力。当光斑搭接率为50%时,测得的最小残余压应力为基体的3.3倍。随光斑搭接率的增加,不同搭接区域表面的平均残余压应力随之增加。搭接率50%时表面平均残余压应力为搭接率30%时表面平均残余压应力的1.36倍。随着搭接次数的增加,表面残余压应力也随之增加,而增幅随之减小。

Laser shock processing（LSP） was carried on 40 Cr surface by Nd：YAG laser under different facula overlapping rates. The residual stress after shock under different overlapping regions was detected by XRD-350 A X-ray diffraction instrument. The results show that the residual stress on the surface after LSP is obviously greater than that before LSP. The minimum measured residual compressive stress is 3.3 times of the substrate when the overlapping rate is 50%. With the increase of facula overlapping rate, the average residual compressive stress under different overlapping regions increases.When the overlapping rate is 50%, the average residual compressive stress is 1.36 times of that of the overlapping rate of 30%.With the increase of overlapping times, the surface residual compressive stress increases, but the amplification reduces.