针对2 mm厚SUS301L不锈钢薄板进行CO2激光-MIG复合焊接实验。研究了保护气体、热源间距、电弧电流、激光功率等工艺参数对焊缝成形及焊接过程的影响规律, 以及复合焊接对装配间隙和错边的适应性。试验结果表明: CO2激光-MIG复合焊接保护气采用He、Ar混合气时可以改善焊接过程稳定性, 当He气比例达到50%即可获得较好效果; 热源间距为2 mm时, 焊接过程波动较小, 所得焊缝成形均匀; 当电弧电流为150 A时, 激光功率为2 000 W时焊缝背面熔宽较1 600 W时小, 在电弧电流超过150 A时, 焊接飞溅严重, 过程稳定性变差。在优化的焊接工艺下, 复合焊接对间隙不大于1.0 mm, 错边不大于1.2 mm的装配误差有良好的适应性, 但是随着装配间隙和错边量的增大, 接头强度逐渐降低, 拉伸试样全部断裂在焊缝中靠近熔合线的粗大柱状晶区, 断裂类型属韧性断裂。

In this paper, SUS301L stainless steel sheet with the thickness of 2 mm was welded using CO2 laser-MIG hybrid. The influence of welding parameters, such as shielding gas, the distance of heat resource, arc current and laser power on weld seam shape and welding process was studied. The adaptability of gap and offset for hybrid welding was investigated. The results indicated that the stability of welding process can be improved using He and Ar gas mixture as shielding gas during CO2 laser-MIG hybrid welding. Furthermore, using 50% He as the shielding gas, the result is the best. When the distance of heat resource from the surface of work-piece is 2 mm, the small welding fluctuation and the uniform weld seam shape can be obtained. When the arc current is 150 A, the foot width at the laser power of 2 000 W is smaller than that of 1 600 W. In addition, the welding spatter is serious when the arc current is more than 150 A. Under the optimized welding parameters, the hybrid welding has good adaptability for gap less than 1.0 mm and offset less than 1.2 mm. But the strength of joint is decreased with the gap and offset increasing. The fractured surface shows the ductile characteristic using the tensile test and the fracture takes place along to the seam close to the fusion-line. The microstructure of the fractured surface took on the course columnar.