Abstract: An experimental design approach to technical parameter optimizing for the laser lap welding of 0.8 mm/1.5 mm SUS301L austenitic stainless steels is studied by using YAG laser in order to reduce the welding distortions of the back of the welding seams while ensuring mechanical properties of welding joints. To determine the optimal laser-welding parameters, a set of mathematical models of welding parameters related to each of the weld characteristics are built. The accuracy of the models are inspected by validation tests, and the error range is smaller than 5%, so they can be used for subsequent optimization analysis. Based on the optimization scheme, the laser power, welding speed, laser incident angle and defocusing distance in the range of 3.50～3.79 kW, 7.40～8.00 m/min, 65° and 0 mm respectively, are identified as the optimal set of process parameters. By experimental study and optimization analysis, it is obtained that the focusing distance has influence only on the deviation of optimal region, and has little effect on the width of optimal region, while the laser incident angle has great effect on both deviation and width of optimal region.

Key words: Austenitic stainless steel, Distortion, Experimental design, Laser welding, Tensile strength