电弧摆动对窄间隙GMAW横焊打底焊道成形的影响

Influence of arc-swing on backing bead formation of narrow-gap GMAW in horizontal position

采用一款新型摆动电弧窄间隙熔化极气体保护焊焊枪,对FH40厚板进行窄间隙横焊试验,探究不同工艺参数对打底焊道成形、熔滴过渡及缺陷的影响规律。结果表明,摆动幅度对焊道的熔宽和表面凹凸度影响最大,焊接速度对熔深和焊道成形的不对称性影响最大;电弧不摆动时,熔池铺展范围小,焊道凸而窄,坡口两侧无法熔合;电弧摆动过程中熔滴过渡形式和熔池流动状态会发生变化,合适的电弧摆动幅度有助于熔池均匀填满坡口,获得侧壁熔合良好、成形对称的打底焊焊道,但过大的摆动幅度会加快熔池下淌,甚至造成焊道外凸、咬边等焊接缺陷。

A new type of swing arc narrow-gap gas metal arc welding torch was used to conduct the narrow-gap horizontal welding test on FH40 thick plates.The relationship between process parameters and backing bead formation,droplet transfer and defects were studied.The results showed that the arc swing amplitude influences greatly on the weld width and the surface formation,and the welding speed has the greatest impact on the weld penetration and the asymmetry of the weld.The molten pool could not widely expand in welding without arc-swing,and the weld bead becomes narrow and convex to result in lack-of-sidewall penetration in the weld.In welding with swing arc,the droplet transfer form and the molten pool flow state could be changed.An appropriate swing amplitude was helpful for the molten pool to fill the groove evenly and to obtain a well-formed symmetrical weld with satisfied sidewall penetration.An excessive large amplitude of arc swing would accelerate the sagging of molten pool,even to cause welding defects such as undercut and weld bead convexity.