采用焊条电弧焊对30CrMnSiA钢焊接接头进行多次(3,4次)补焊试验,研究了补焊次数对接头组织和力学性能的影响。结果表明:补焊次数的增加对接头焊缝区域的显微组织类型影响不大,原始焊缝和补焊焊缝组织均为奥氏体柱状晶,但会导致原始焊缝区域的晶粒粗化和热影响区的大角度晶界分布密度下降,并减少热影响区的马氏体数量,从而对接头强度产生不利影响。补焊4次接头的抗拉强度较补焊3次接头降低了7.8%,断后伸长率降低了25.3%,但断裂机制仍为韧性断裂;补焊4次接头的抗弯性能和硬度也低于补焊3次接头。

Multiple repair welding (for three and four times) tests were carried out on 30CrMnSiA welded joint by shielded metal arc welding. The effect of the repair welding time on the microstructure and mechanical properties of the joint was studied. The results show that increasing repair welding time had little effect on the microstructure type of the joint weld zone. The microstructures of the original weld and the repairing weld both consisted of austenite columnar crystals. Increasing repair welding time could lead to grain coarsening in the original weld zone, and reduce the distribution density of high angle grain boundaries and martensitic quantities in the heat-affected zone, resulting in negative effects on the strength of the joint. The tensile strength of the four-time repair welding joint was reduced by 7.8% and the percentage elongation after fracture was reduced by 25.3% comparing with those of the three-time repair welding joint, but the fracture mechanism was still ductile fracture. The bending resistance and hardness of the four-time repair welding joint were also lower than those of the three-time repair welding joint.