Investigation on the microstructure and proper-ties of flux core gas shielded welding joint of Q620 steel

Q620钢药芯焊丝气体保护焊接头组织与性能的研究 Investigation on the microstructure and proper-ties of flux core gas shielded welding joint of Q620 steel 邢珂 XING Ke 1 first-author 李博文 LI Bowen 2 内蒙古机电职业技术学院 内蒙古机电职业技术学院 Department of Metallurgy and Material Engineering,Inner Mongolia Technical College of Mechanics and Electrics Department of Metallurgy and Material Engineering,Inner Mongolia Technical College of Mechanics and Electrics 中科院金属研究所 中科院金属研究所 Material environment corrosion research center,metal research institute,Chinese academy of sciences Material environment corrosion research center,metal research institute,Chinese academy of sciences 在非预热状态下,采用Ar+CO 2 混合气体保护焊方法,选择低合金系碱性渣系药芯焊丝,在三种热输入下对Q620钢进行焊接。通过进行焊接接头质量分析、焊缝金属化学成分分析、显微组织观察和力学性能测试,研究了Q620钢的可焊性和工程使用性。结果表明,Q620钢常温下可焊接性良好,焊缝区合金元素分布均匀,当焊接热输入由低向高变化时,焊缝区组织由铁素体+珠光体向贝氏体+马氏体组织转变,并且焊缝区强度下降,硬度上升。随着热输入的增大,焊缝区冲击断口形貌由韧性断裂向着韧窝+准解理的混合断裂方式转变。 The Ar+CO 2 gas shielded welding method was used in the condition of non-preheating,and the low-alloy basic slag flux-cored wire was selected to weld Q620 steel under three heat inputs. The weldability and engineering usability of high strength and low alloy Q620 steel were studied by welding joint quality analysis,weld metal chemical composition analysis,microstructure observation and mechanical property test. The results show that Q620 steel has good weldability at room temperature,and the alloying elements in the weld zone are evenly distributed. When the welding heat input changes from low to high,the microstructure of the weld zone changes from ferrite +pearlite to bainite +martensite,and the strength and hardness of the weld zone decrease. With the increase of heat input,the impact fracture morphology of weld zone changes from ductile fracture to hybrid fracture mode of dimple and quasi-cleavage. 药芯焊丝气体保护焊 Q620高强钢 力学性能 焊缝组织 可焊性 flux core gas shielded welding Q620 steel mechanicalproperty weldstructure weldability TG407 2022-03-08 5 50