对D406钢和20钢进行了角焊接, 研究了异质钢焊接接头的显微组织和力学性能, 此外还研究了D406钢对接接头的力学性能。结果表明: 此异质钢焊接接头D406钢侧焊缝区的显微组织主要以板条马氏体为主, 熔合区主要是针状马氏体, 该区是接头中最易产生裂纹的区域; D406A钢侧焊接接头热影响区靠近焊缝处的硬度最大, 约为659 HV; 20钢侧焊接接头焊缝区的最高硬度约为350 HV, 低于D406A钢侧的最高硬度, 因而D406A钢侧热影响区的淬硬倾向相对较大; D406A钢对接接头熔合区的冲击功小于母材和焊缝区的冲击功, 该焊接接头的拉伸试样均断裂于在焊缝区, 抗拉强度的平均值为679 MPa, 这与其焊缝区的组织为板条马氏体有很大关系。

Microstructure and mechanical properties of heterogeneous joint of D406A steel and 20 steel were studied, meanwhile, the mechanical properties of butt joint of D406 steels also were studied. The results show that the microstructure of weld seam zone at the side of D406A steel was mainly lath martensite, and microstructure of fusion zone was mostly lamellar martensite. Cracks were easy to appear in the fusion zone. Microhardness near weld seam in HAZ of welded joint at the side of D406A steel was maximum, the value was about 659 HV. The highest microhardness in weld seam zone of welded joint at the side of 20 steel was about 350 HV, which was lower than the highest microhardness at the side of D406A steel. Therefore, the hardening of HAZ at the side of D406A steel was relatively large. Impact energy of fusion zone of D406A steels butt joint was less than those of base metal and weld seam zone, the tensile fracture area of the butt joint located at weld seam zone, and the average tensile strength of the butt joint was 679 MPa, which is closely related with the lath martensite in the weld seam zone.