超细晶粒钢低热输入背面辅助成形焊接工艺研究  

Research on Welding Technology of Low Heat Input and Back Aided Forming of Ultra-fine Grain Steel

作　　者：王燕[1] 张富巨[2] 

机构地区：[1]三峡大学机械与动力学院,湖北宜昌443002 [2]武汉大学动力与机械学院,湖北武汉430072

出　　处：《热加工工艺》2015年第3期48-50,54,共4页Hot Working Technology

摘　　要：对400 MPa级超细晶粒钢进行STT焊接电源下的CO2气体保护焊,采用低热输入窄坡口自制焊剂垫背面辅助成形工艺得到焊缝成形美观、根部和侧壁熔合良好以及热影响区极窄的焊接接头。研究结果表明:低热输入窄坡口条件下,焊剂垫只起引弧作用而不起强迫成形作用,只用熔敷金属的自重以及电弧吹力的作用来达到辅助成形目的;小曲率焊剂垫更利于加大电弧扩展角,使得焊缝成形更为合理。在低热输入窄坡口背面辅助成形工艺下所得接头力学性能均优于母材,焊缝区是因为焊材的合理选择。扫描电镜观察显微组织发现HAZ生成了晶粒较小不同方向不同晶界的多种非平衡组织,尤其是出现了能改善力学性能的粒状珠光体。400MPa ultra-fine grain steel was welded by CO2 gas shielded arc welding under STT welding power source. The welding technology of low heat input, narrow grove and back aided forming can get excellent welded joint,which has beautiful formation, good fusion of root and lateral wall and very narrow HAZ. The results show that flux backing aided forming is only used as arc ignition but not forced forming by deposited metal deadweight and arc spray force under low heat input and narrow grove. Small curvature flux backing is more conducive to increase arc diffusion angle, which can make weld shape to be more reasonable. The mechanical properties of the welded joint are superior to the base metal because the excellent performance of the weld zone can be gotten by the reasonable selection of welding material. By SEM analysis, HAZ generates various non-equilibrium microstructure which is smaller grain and different direction and grain boundary, especially the appearance of the granular pearlite can improve the mechanical properties

关 键 词：超细晶粒钢 低热输入 背面辅助成形 焊接工艺 

分 类 号：TG457.11[金属学及工艺—焊接]