焊丝自转式MAG焊焊接过程与接头组织分析

Study on welding process and joint microstructure of rotated wire metal active gas welding

提出了通过焊丝自转搅动熔池进而细化焊缝组织的MAG焊接新方法.试验中采集了焊接过程电信号和熔池形态,分析了焊丝转速对低碳钢表面堆焊接头组织特征的影响.结果表明,焊丝自转可以增加短路过渡的频率,使焊接过程更稳定,熔滴过渡近似熵的计算也证明焊接过程的稳定性可以明显地提高.利用钨颗粒示踪技术可以发现焊丝自转能够显著增加熔池金属流动性,熔池宽度随着焊丝自转速度的改变先变大后变小,焊缝金相组织分析也证明熔池流动性的改变可以有效细化焊缝金属晶粒,减少联生结晶的生成.

A new rotated wire metal active gas welding process was put forward to improve molten metal flow and to refine weld microstructure.welding current,arc voltages and weld pool behaviors ware collected to analyze the effect of rotation velocity change on the joint microstructure when build-up welding on mild steel.The results showed that the rotation of the welding wire could add transition frequency of short circuiting transfer and improve the stability of the welding process.The calculation of the droplet transfer approximate entropy also proved the stability of the welding process was improved.The flow of molten pool was added by the additional motion of the welding wire and this can be seen from the tungsten particle tracer method results.The width of the bead firstly increased and then decreased.The joint microstructure could be refined obviously and the epitaxial growth of weld metal was restrained.