热输入对25 mm厚A710钢MAG焊接头组织与性能的影响  

Effect of heat input on microstructure and mechanical properties of MAG welded joint of 25 mm thick A710 steel

作　　者：王亚平 吕纯洁 李世旺 李胜 赵飞 杨志斌 WANG Yaping;LYU Chunjie;LI Shiwang;LI Sheng;ZHAO Fei;YANG Zhibin(CRRC Datong Co.,Ltd.,Datong 037038,Shanxi pro.,China;School of Materials Science and Engineering,Dalian Jiaotong University,Dalian 116028,Liaoning pro.,China)

机构地区：[1]中车大同电力机车有限公司,山西大同037038 [2]大连交通大学材料科学与工程学院,辽宁大连116028

出　　处：《焊接技术》2025年第3期18-23,I0001,I0002,共8页Welding Technology

摘　　要：文中采用不同热输入分别对25 mm厚A710钢进行多层多道MAG焊,对比分析不同热输入对接头微观组织和力学性能的影响。试验结果表明:常规热输入和大热输入焊缝成形质量均较好,不同热输入焊缝组织形态相似,常规热输入接头组织晶粒尺寸略小;大热输入接头热影响区宽度略大,不同热输入接头硬度均为焊缝区最低,盖面层大热输入接头焊缝区和热影响区硬度值更高,打底层常规热输入接头焊缝区和热影响区硬度值更高;常规热输入和大热输入接头弯曲性能均良好;大热输入接头拉伸性能低于常规热输入接头的,屈服强度和断后伸长率下降较明显,但抗拉强度下降不显著,拉伸试样均断裂在焊缝区,微观断口均呈现塑性断裂特征;在-40,-50,-60℃下,常规热输入接头冲击性能均优于大热输入接头的,不同热输入接头冲击性能均随温度降低而降低,尤其是大热输入接头的降低更明显。In this paper,25 mm thick A710 steel were welded by using multi-layer and multi-pass MAG welding with different heat inputs,and the effects of different heat inputs on the microstructure and mechanical properties were analyzed.The results indicated that well-formed weld could be obtained with conventional and large heat input,the microstructures of different heat-input welds were similar,and the grain sizes of conventional heat input joints were slightly smaller.The heat affected zone width of the large heat input joint was larger,the microhardness in the weld zone was the lowest for both conventional and large heat input joints.The microhardness of the large heat input joint was higher for the covering layer,but the microhardness of the conventional heat input joint was higher for the backing layer.Both the conventional and large heat input joints had good bending properties.The tensile properties of large input joints were lower than those of conventional heat input joints,and the yield strength and elongation decreased significantly,but the tensile strength decreased non-significantly.The tensile specimens all fractured in the weld zone,and the microscopic characteristics were plastic fracture.At-40,-50 and-60℃,the impact performances of the conventional heat input joints were all better than those of the large heat input joints.The impact performances of different heat input joints decreased as the temperature reduced,especially the large heat input joints.

关 键 词：A710钢 MAG焊 热输入 微观组织 力学性能 

分 类 号：TG404[金属学及工艺—焊接]