坡口角度及焊丝偏移量对钛/铝冷弧MIG焊接头显微组织与力学性能的影响  

Influence of bevel angle and wire offset on the microstructure and mechanical properties of Ti/Al joint by cold arc MIG welding

作　　者：魏守征[1] 王志英 任晓鹏 王建国 WEI Shouzheng;WANG Zhiying;REN Xiaopeng;WANG Jianguo(Welding Research Center,North University of China,Taiyuan,030051,China;Jiangyang Chemical Limited Company of China Jinxi Weapon Industrial Group,Taiyuan,030051,China;The Laboratory Center,Taiyuan Heavy Industry Transit Equipment Co.,Ltd.,Taiyuan,030051,China)

机构地区：[1]中北大学,焊接研究中心,太原030051 [2]中国兵器晋西集团江阳化工有限公司,太原030051 [3]太原重工轨道交通设备有限公司,太原030051

出　　处：《焊接学报》2021年第8期59-66,I0004,I0005,共10页Transactions of The China Welding Institution

基　　金：国家自然科学基金资助项目(51805492);山西省自然科学基金资助项目(201801D221149).

摘　　要：采用SAl 5183焊丝对TA2钛/5A05铝进行脉冲冷弧MIG焊.研究钛侧坡口角度θ及焊丝偏移量d对接头成形及显微组织与力学性能的影响.结果表明,坡口角度过小时,接头上部钛局部熔化而根部结合不良,Ti/Al界面组织差异大;坡口角度过大则出现焊缝下塌;坡口角度在30°~45°范围内,Ti/Al界面组织差异小且结合良好.焊丝偏向钛侧时,接头上部钛局部熔化而根部结合不良,Ti/Al界面组织差异大;焊丝向铝侧偏移过大则出现焊缝下塌;焊丝偏铝侧0~1 mm时,Ti/Al界面组织差异小且结合良好.试验获得的优化工艺为坡口角度θ=35°,焊丝偏铝d=0.5 mm.最佳工艺下,接头上部Ti/Al钎焊界面形成了Ti_(3.3)Al和TiAl_(3)两层金属间化合物;接头下部则通过形成一层TiAl_(3)实现钎焊结合;接头平均抗拉强度达198 MPa.创新点:(1)揭示了坡口角度及焊丝偏移量对钛/铝冷弧MIG焊接头成形、Ti/Al界面组织特性及接头抗拉强度影响规律.(2)揭示了优化工艺下钛与铝异种金属冷弧MIG焊结合机理.Cold arc MIG welding of TA2 titanium and 5A05 aluminum alloy was conducted with SAl 5183 wire.The influence of bevel angle in titanium and wire offset on joint forming and the Ti/Al interfacial microstructure was studied.Partial melting of top titanium and poor bonding of the root appeared in the same joint when the bevel angle is too small.However,Weld sag was observed with too large bevel angles.With the bevel angle is in the range of 30°~45°,good joint forming and sound interfacial combination along the thickness direction were observed.Partial melting of top titanium and poor bonding of the root appeared in the same joint when the welding wire was point to titanium side.Weld sag was observed with too large wire offset towards aluminum.Good joint forming and sound interfacial combination were observed with the wire offset towards aluminum was in the range of 0~1 mm.The optimal parameters obtained were that the bevel angle was 35°in titanium and the wire offset was 0.5 mm towards aluminum,the average tensile strength reached up to 198 MPa.The titanium and the weld metal were brazed by the formation of a Ti_(3.3)Al layer and a TiAl_(3)layer in the upper region of the joint.While only a TiAl_(3)layer was formed between titanium and weld metal in the bottom region of the joint .Highlights:(1)The influence of bevel angle in titanium and wire offset on joint forming,the Ti/Al interfacial microstructure and the mechanical properties was revealed.(2)The joining mechanism of the cold arc MIG welded Ti/Al joint was revealed.

关 键 词：冷弧MIG焊 坡口角度 焊丝偏移量 显微组织 力学性能 

分 类 号：TG457.19[金属学及工艺—焊接]