Abstract: At present, there is still little research on the mechanism and correction of external instability deformation after ultra-thin plate welding. A finite element model based on shell element was established to analyze the wave deformation of 0.07 mm thick stainless steel foil caused by laser welding. A thermal-mechanical sequential coupling analysis was conducted. The waveform distribution of simulation was in good agreement with the experiments. The welding stress on the whole weld length will balance itself in the welding process, and there will be compressive stress outside the tensile stress zone to balance, resulting in interval distribution of local compressive stress zone and wave deformation. The out-of-plane instability deformation of the foil was greatly reduced by using 0.15% pre-stretching method. The main cause is the transformation of plastic strain from compression to tension in the weld after welding. The wave deformation at the weld can be corrected by roller rolling. The overall out-of-plane deformation of the ultra-thin plate was reduced from the original 0.46 mm to 0.25 mm by rolling. The foil was close to flatness after rolling the diameter 72 mm roller. The height difference of wave deformation at the weld was basically controlled within 0.002 mm. The research results have positive reference function for improving the welding quality of ultra-thin plate structure.

Key words: wave deformation, finite element analysis, rolling, pre-tension