通过扫描电子显微镜(SEM)、电子背散射分析(EBSD),研究了TRIP590钢激光焊接接头的界面微观结构和形成机理。SEM分析表明,焊接接头焊缝区组织为马氏体组织,热影响区组织主要是贝氏体和铁素体,离焊缝位置越近,马氏体量越多。EBSD分析表明,母材区的晶粒分布均匀,都是大角度晶界,没有明显的择优取向。热影响区晶粒大小不均,贝氏体有相同或相近的取向。焊缝区板条尺寸最为粗大,有明显的织构。残余奥氏体弥散分布在晶粒内部或晶界,焊缝和热影响区晶界取向差都是1°~5°之间的小角度晶界,大量的小角度晶界导致焊缝与热影响区的塑性要小于母材。 The interfacial microstructure and formation mechanism of TRIP590 steel laser welded joints were studied by scanning electron microscope (SEM) and electron backscatter analysis (EBSD). The SEM analysis shows that the welded joints are martensite and the HAZ is mainly composed of bainite and ferrite. The closer to the weld, the more martensite. EBSD analysis shows that the grain distribution of the base metal region is uniform and all are large-angle grain boundaries with no obvious preferred orientation. The heat affected zone is not uniform in grain size and has the same or similar orientation of bainite. Weld seam area plank size is the most coarse, obvious texture. The retained austenite is dispersed in the grain boundaries or grain boundaries, and the grain boundary difference between the weld and the heat affected zone is a small angle grain boundary between 1 ° and 5 °. A large number of small-angle grain boundaries lead to weld and heat The plasticity of the affected area should be less than the base metal.