Visual Study on Surface Micro-Topography and Residual Stress of Sheet Metal after Pulsed Laser Peening

Abstract

In order to control surface microscopic quality of sheet metal after laser peen forming (LPF), visual numerical analyses for SUS304 plate was employed. Based on the FEM code ABAQUS/CAE, a conversion model of laser shock wave loading was established. The tracks controlling technology of LPF was solved by functional element programs. The micro-plastic flow process of surface material was analyzed, and the change of residual stress distribution as well as micro-topography in real time can be shown with the movement of pulsed laser beam. On the basis of FEM simulation, LPF experiments were carried out. The micro-topography and section analysis were analyzed by AFM, surface residual stress was measured by X-ray diffraction method. It was found that after LPF, the surface irregularity was less than 0.15μm, the variation of average surface roughness was slight, both sides of deformed sheet existed useful residual compressive stress, and the maximum stress was -616.1MPa, meanwhile average surface micro-hardness in the peened zone was higher than the base’s surface. Simulative results show a good agreement with experimental results.