钛合金T形接头双面双弧MIG焊工艺

Double-sided double-arc MIG welding process of titanium alloy T-joint

首次将双面双弧熔化极惰性气体保护焊(MIG焊)应用到大厚度的钛合金T形接头的焊接上,针对焊接工艺参数对T形接头成形及缺陷形成的影响规律展开系统研究。结果表明,焊枪间距过大或过小都会导致焊接气孔增多,气孔主要为工艺气孔;打底焊时应尽量减小焊枪角度α1,而填充焊及盖面焊时应适当增加α1;焊枪角度α2为60°左右时气孔发生率最低;单枪焊接热输入越大,熔池高温停留时间越长,气孔数量越少;焊接电流I/焊接速度v对焊缝成形情况有重要影响,随着v的增加,I与v的匹配性得到改善。与普通单枪TIG焊相比,使用双面双弧MIG焊接工艺制备的“十字形”接头的冲击吸收能量A KV明显提高,接头塑、韧性更高,综合性能优良。

Double-sided double-arc MIG welding was applied to weld T-joint of titanium alloy with large thickness for the first time,and the influence of welding parameters on formation and defect forming of T-joint of titanium alloy was systematically studied.The result showed that too large or too small distance between welding gun and workpiece would lead to the increase of weld porosities,which were mainly process porosities.The welding gun angleα1 should be reduced as far as possible during backing welding,while the welding gun angleα1 should increase appropriately during filling and cosmetic welding.The incidence of porosity was lowest when the welding gun angleα2 was about 60°.The larger the heat input of single-arc TIG was,the longer the high-temperature residence time of the molten pool was and the smaller the quantity of porosity was.The ratio of welding current I to welding speed v had an important influence on formation of T-joint.The matching of I and v was improved with the increase of v.Compared with ordinary single-arc TIG,the impact energy A KV of the cruciform joint prepared by double-sided double-arc MIG welding was significantly improved,and the joint had better plasticity,toughness,and comprehensive performance.