采用Roin 4 kW光纤激光器对镀锌钢和高强钢进行激光叠焊, 通过电子显微镜、光学显微镜和维氏硬度仪等, 研究不同板间间隙对焊接接头表面、截面形貌、宏观和微观缺陷、显微组织、显微硬度的影响。结果表明, 当间隙为0.1～0.2 mm时, 焊缝成形良好, 叠焊结合面宽度稳定, 焊缝质量缺陷少, 剪切强度较镀锌板母材大, 且焊缝具有优良的综合性能。镀锌钢和高强钢侧焊缝、热影响区均未出现气孔、裂纹等缺陷。镀锌钢侧焊缝组织以马氏体为主, 高强钢侧焊缝组织为板条马氏体、针状铁素体和晶界铁素体。由于镀锌钢和高强钢侧热影响区及焊缝区产生了淬火马氏体, 其显微硬度均比母材高。

Galvanized steel and high strength steel were lap welded using the ROIN 4 kW fiber laser. With the help of digital microscope, optical microscope and vicker hardness tester, the influences of gap between sheets on weld topography, cross section, quality defects, microstructure and microhardness were studied. The results indicate that the welding joint can obtain excellent weld, stable combination width, few drawbacks of quality and very good comprehensive performances when the gap is between 0.1 mm and 0.2 mm. Both the sides of the galvanized steel and the high strength steel, the welds and the heat affected zones are without any defects, such as pores and cracks. The weld microstructure of galvanized steel side is mainly composed of martensite, and the weld microstructure of high strength steel side are mainly composed of lath martensite, acicular ferrite, and grain boundary ferrite. Due to the formation of the quenching martensite in the heat affected zones and welds of galvanized steel and high strength steel, the microhardness are higher than the parent metal.