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采用TIG熔-钎焊焊接方法,以镁合金焊丝为填充材料,对镁合金与镀锌钢进行连接实验,并分析热输入量对接头显微组织和力学性能的影响.热输入量过小会阻碍镁/钢界面反应层的形成而使得焊缝难以焊合,热输入量过大又会促进焊缝内部脆性第二相的长大,降低接头力学性能.接头强度随着焊接电流和焊接速度的增大都呈现先上升后下降的趋势,电流为70 A时强度达到最大,该值接近AZ31B母材的88.7%.此时断裂发生于焊缝熔焊区,断面出现大量韧窝和撕裂棱,呈现出塑性断裂特征.
TIG fusion welding method was used to weld the magnesium alloy and galvanized steel with magnesium alloy wire as the filler, and the effect of heat input on the microstructure and mechanical properties of the joint was analyzed. Hinder the formation of the reaction layer of magnesium / steel interface and make the weld difficult to weld, the heat input is too large will promote the growth of brittle second phase of the weld, reduce the mechanical properties of the joint.The joint strength with the welding current and welding speed Increase first and then decrease, and reach the maximum value when the current is 70 A, which is close to 88.7% of the AZ31B base metal.At this time, the fracture occurs in the weld zone of the weld and a large number of dimples and tear edges , Showing a plastic fracture characteristics.