超窄间隙焊接中焊剂片与电弧相互作用机制分析

Interaction mechanism of flux band and arc in ultra-narrow gap welding

通过向间隙宽度为4 mm的I形坡口中预置焊剂片进行超窄间隙焊接试验,采用一种快速中断电弧的方法,保留焊接过程中焊剂片、坡口底部和侧壁的熔化形态,分析了焊剂片与电弧相互作用面积对电弧受约束程度的影响.结果表明,增加电弧电压或降低焊剂片熔点,可使焊剂片熔化面积增大,固壁约束面积减小.当焊剂片熔化面积大于一定值而小于固壁约束面积时,电弧受约束程度适中,电弧加热区域被控制在坡口根部和两侧壁,从而获得成形良好的焊缝.当焊剂片熔化面积大于固壁约束面积时,电弧受约束程度减弱,电弧加热区域集中在两侧壁上,很难形成一个完整的熔池,最终形成了带有大量孔洞的焊缝.

Ultra-narrow gap welding was conducted on 4 mm wide I-type groove deposited with flux band. By interrupting arc quickly,the melting forms of flux band,groove bottom and side walls in welding were retained. The influence of interaction area of flux band and arc on the constricted degree of arc was analyzed. The results showed that increasing voltage or decreasing the melting point of flux band could increase the melting area of flux band and decrease the wall constricted area. When the melting area was larger than a certain value but smaller than the wall constricted area,a suitable constricted degree of arc was acquired and the arc heating area was controlled in the groove bottom and side walls,so a weld with good formation was made.When the melting area was larger than the wall constricted area,the constricted degree of arc decreased and the arc heating area was restricted in the two side walls,then it was difficult to form a complete molten pool. Finally,a weld with a large number of holes formed.