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针对汽车用钢的焊接问题,利用光学显微镜、扫描电镜、硬度和拉伸试验研究分析了不等厚异种钢激光拼焊板接头的组织及性能。结果表明,焊缝区为板条马氏体组织,板条之间有残留奥氏体组织存在。熔合区附近的组织结构比较复杂,主要由马氏体和贝氏体构成。而相变诱发塑性(TRIP)钢热影响区组织主要由贝氏体和铁素体组成,且晶粒比较细小,双相钢(DP)接头热影响区中存在显著的马氏体组织,但几乎不存在过热区组织。接头焊缝区的硬度达到母材的1.6倍以上,此外接头宏观断裂发生在薄板DP钢的母材区。
Aiming at the welding problem of automotive steel, the microstructures and properties of welded joints of unequal thickness dissimilar steel were analyzed by optical microscope, scanning electron microscope, hardness and tensile test. The results show that the weld zone is lath martensite with residual austenite between the laths. The organization of the structure near the fusion zone is complex and consists mainly of martensite and bainite. However, the microstructure of the heat-affected zone in phase-change-induced plasticity (TRIP) steel mainly consists of bainite and ferrite, and the grains are relatively small. There is significant martensite in the heat-affected zone of duplex steel (DP) There is almost no overheating zone organization. Joint weld zone hardness reached 1.6 times more than the base material, in addition to macroscopic fracture joints occurred in the sheet of the base material of DP steel.