Effects of High Frequency Impact Vibration Stress Relief on Residual Stress and Microstructure of a Laser Surface Treated S355 Steel
B.P. Gu, P. Wang, X. Hu, Z.D. JIN, J.T. Lai, G.H. Xu, Z.S. Yang, Z.P. Huo and Z.S. Wang
The high frequency impact vibration stress relief (HFIVSR) technology is studied. The S355 steel specimens with large tensile residual stress were prepared by laser surface treatment with a fibre laser, which is used to simulate the welding process. Then the effects of the HFIVSR on residual stress and microstructure for the S355 steel specimens were discussed. In addition, the multi-degree of freedom (DOF) system model of metal particles was developed to reveal the mechanism of the HFIVSR. The experimental results indicate that the tensile residual stress can be effectively eliminated and homogenized by the HFIVSR. The HFIVSR will not change the microstructure of the materials and there are no considerable changes in the grain size for the S355 steel before and after the HFIVSR; furthermore, the HFIVSR can slow down the lattice distortion energy and thus the tensile residual stresses in the S355 steel specimens can be eliminated. The HFIVSR process is expected to be widely used in field of the mechanical engineering.
Keywords: Fibre laser, S355 steel, laser surface treatment, high frequency impact vibration stress relief (HFIVSR), residual stress, microstructure