TRIP980高强钢电阻点焊接头的组织及力学性能

采用电阻点焊对TRIP980高强钢进行焊接. 通过单因素法和焊后回火优化了焊接参数和工艺，研究了较优焊接参数和工艺时的接头熔核显微组织及力学性能，结果表明，优化参数为9.5 kA，22 cycle，3 kN，接头熔核为粗大的马氏体组织，接头硬度为617.1 HV，最大拉剪载荷为17.8 kN；在此基础上增加焊后回火，回火电流6.3 kA、回火时间13 cycle，接头组织显著细化，接头硬度降低至574 .0 HV，接头最大拉剪载荷提高到19.5 kN，增幅为9.6%，断口形式由原先的界面断裂转变为纽扣断裂.

Study on microstructure and mechanical properties of spot welded joints of TRIP980 high strength steel

TRIP980 high strength steel was welded by resistance spot welding. By optimizing the parameters and process of resistance spot welding, the variation of microstructure and mechanical properties of weld nugget was studied. The results showed that the microstructure of nugget was gross martensite structure, the hardness of the joint was 617.1 HV and the maximum tensile force was 17.8 kN when optimized welding parameters were 9.5 kA, 22 cycle, 3 kN. Temper process was performed on the basis of this. When the tempering current and time were 6.3 kA and 13 cycles, respectively, the grain size of the joint microstructure was the smallest, the joint hardness reduced to 574 .0 HV, and the joint tensile force was increased to 19.5 kN, increased by 9.6%. The fracture form was transformed from the original interface fracture to the button fracture.