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通过富氩气体保护焊方法,采用直径为1.2 mm的ER70S-6实芯焊丝对1.4 mm厚的DP590镀锌钢板进行搭接焊,并对搭接接头的金相组织进行了观察,对接头拉伸剪切强度、显微硬度等力学性能进行了测试。结果表明,接头不完全正火区主要组织为铁素体+马氏体+少量的粒状贝氏体,细晶区主要组织为粒状贝氏体,粗晶区主要组织为粒状贝氏体+板条铁素体+少量针状铁素体,焊缝组织主要为针状铁素体+先共析铁素体。焊接接头的拉剪强度均在629 MPa以上,断裂位置位于母材,即焊缝的实际拉剪强度高于母材强度。焊缝平均硬度最高,热影响次之,母材最低。
By argon-gas-shielded arc welding method, the 1.2 mm diameter ER70S-6 solid wire was used to lap-weld the 1.4 mm thick DP590 galvanized steel and the microstructure of the lap joint was observed. Tensile shear strength, microhardness and other mechanical properties were tested. The results show that the main microstructure of the joints is not ferrite + martensite + a small amount of granular bainite, the main structure of fine grain is granular bainite, the main structure of coarse grain is granular bainite + plate A small amount of ferrite + acicular ferrite, weld microstructure mainly acicular + pro-eutectoid ferrite. The tensile shear strength of the welded joints are above 629 MPa, the fracture location is located in the base metal, that is, the actual tensile shear strength of the weld is higher than that of the base metal. The average hardness of the weld is the highest, followed by the heat, the lowest base metal.