316奥氏体不锈钢高频感应焊接技术及缺陷形成机理  

High Frequency Induction Welding Technology and Defect Formation Mechanism of 316 Austenitic Stainless Steel

作　　者：王超 陈琪 肖述广 董仕节 谢志雄 罗平 解剑英 WANG Chao;CHEN Qi;XIAO Shuguang;DONG Shijie;XIE Zhixiong;LUO Ping;XIE Jianying(School of Materials and Chemical Engineering,Hubei University of Technology,Wuhan 430068,China;Wuhan Botal New Materials Technology Co.,Ltd.,Wuhan 430058,China)

机构地区：[1]湖北工业大学材料与化学工程学院,武汉430068 [2]武汉市博钛新材料科技有限公司,武汉430058

出　　处：《材料导报》2022年第19期157-161,共5页Materials Reports

基　　金：国家自然科学基金(51771071)。

摘　　要：采用高频感应焊接技术对壁厚0.3 mm的316奥氏体不锈钢进行焊接试验,研究焊接工艺对焊缝宏观形貌、接头组织及力学性能的影响,并讨论了焊接缺陷形成机理。结果表明,开口角较小时,毛刺以椭球状驼峰缺陷成形,随着开口角的增加驼峰缺陷呈减少趋势;焊接点有水渍聚集时,易出现焊接飞溅。当热输入为16.5 kJ/m、焊接速度为80 m/min、开口角为6°、钢带边缘保持干燥和洁净时,可获得无缺陷连续毛刺形貌。焊缝组织为奥氏体+δ-铁素体,焊缝区平均硬度值达到289HV,接头平均抗拉强度约为920 MPa,高于母材抗拉强度(760 MPa)。焊缝强度高的原因是挤压辊的压力将脆性杂质从焊缝中挤出,提高了晶粒间的结合能力,且焊缝成形好,焊缝区晶粒组织细小,奥氏体晶界析出大量阻碍位错运动的δ-铁素体。本工作提出了一种熔融金属流动模型分析其驼峰缺陷形成机理,即:焊接时开口角小,熔融金属内部的平衡状态短时间内随着熔融金属的聚集长大而被破坏,驼峰形成;开口角增大到合适角度时,焊接状态保持稳定,最终连续毛刺形成。The high-frequency induction welding technology was used to conduct the welding test on 316 austenitic stainless steel with a wall thickness of 0.3 mm.The influence of welding process on the macro morphology of weld,microstructure and mechanical properties of joint was studied,and the formation mechanism of welding defects was discussed.The results show that when the opening angle is small,the burr is formed by ellipsoid hump defect,and the hump defect decreases with the increase of opening angle.When the welding points are gathered with water stains,welding spatter is prone to occur.When the heat input is 16.5 kJ/m and the welding speed is 80 m/min,the opening angle is 6°,and with the edge of the steel strip dry and clean,the defect-free continuous burr morphology can be obtained.The microstructure of the weld is austenite andδ-ferrite.The average hardness of the weld zone reaches 289HV,and the average tensile strength of the joint is about 920 MPa,which is higher than that of the base metal(760 MPa).The high strength of the weld can be attributed to the extrusion of brittle impurities from the weld by the pressure of the extrusion roller,which improves the bonding ability between grains,and the good formation of the weld,with a result that the grain structure in the weld area is fine,and a large number ofδ-ferrites precipitate at the austenite grain boundary hindering the dislocation movement.A flow model of molten metal is proposed to analyze the formation mechanism of hump defects,that is,the opening angle is small during welding,and the equilibrium state inside the molten metal is destroyed with the aggregation of molten metal in a short time to form humps.When the opening angle increases to a suitable one,the welding remains stable and eventually forms a continuous burr.

关 键 词：奥氏体不锈钢 高频感应焊接 微观组织 焊接缺陷 形成机理 

分 类 号：TG456.9[金属学及工艺—焊接]