铝合金变极性等离子弧穿孔横焊焊缝成形规律分析

以穿孔等离子弧焊接过程中形成的穿孔熔池为研究对象,根据熔池热源形态的特点,采用数值模拟与试验相结合的手段研究横焊位置下的铝合金变极性等离子弧焊缝成形.由于焊接速度波动和工件厚度的影响,体热源作用下的穿孔熔池背面存在最高温度点和最大熔宽截面相背离的现象;因此通过对穿孔熔池背面进行分区和定义,提出温宽偏离度概念,即熔池背面最高温度点和最大熔宽截面的偏离程度,用以描述穿孔熔池状态及焊缝成形;通过调节焊枪角度来改变焊接过程中的温宽偏离度,在其它参数不变的情况下减轻重力在焊接过程中对焊缝成形的影响,实现变极性等离子弧穿孔焊接在横焊位置上的良好成形.

Principle of weld formation in variable polarity keyhole plasma arc transverse welding of aluminum alloy

Taking the keyhole molten pool in plasma arc welding as the study object,the weld formation in variable polarity keyhole plasma arc transverse welding of aluminum alloy was investigated by using both experiments and numerical simulation according to the characteristic of heat source.The study indicates the deviated phenomena between the highest temperature point and the widest fusion width section in keyhole molten pool root surface under the heat source due to the welding speed fluctuation and effect of thickness of plate.By making division of the keyhole molten pool root surface,the concept named temperature width deviation was defined as the deviation between the highest temperature point and the widest fusion width point in molten pool root surface,to describe the state of keyhole molten pool root surface and the welding formation.Temperature width deviation was changed by adjusting the welding torch position,so as to reduce the effect of gravity in welding process,with other parameters being unaltered,to get a good weld formation of variable polarity keyhole plasma arc welding at transverse position.