激光-电弧复合焊接咬边缺陷分析及抑制方法

为了提高激光-电弧复合焊接的可靠性,对复合焊接咬边缺陷成形机理及抑制方法进行了研究.结果表明,激光能够提高复合焊接的临界咬边速度,最高可达电弧焊接的5倍.在激光-电弧相互作用下,复合焊接存在两种抑制咬边的机理.一种是改变焊趾处固、液、气三相的表面张力状况,形成指向熔池外部的合力.另一种是通过提高熔池内温度梯度和热输入来增加熔池内由内向外的流动速度和时间,使熔化金属能够流向并填充焊趾,这种抑制机理作用更为显著.试验确定了复合焊接临界咬边速度的经验公式和电弧电压的合理调节范围.

Mechanism and remedy of undercut formation during laser-arc hybrid welding

To enhance the reliability of laser-arc hybrid welding, undercut formation and its remedy mechanisms during this process were discussed.The results demonstrated that laser can increase undercut critical speed of hybrid welding, which reaches 5 times than that of arc welding with appropriate welding parameters.Two undercut remedying mechanism resulted from laser-arc interaction were found during hybrid welding.The one is the surface tension state of three phases (solid, liquid and gas)at weld toe is changed by laser-arc synergic effects and form a resultant force pointing to the outside of molten pool.The other is the enhancement of flow speed and time of molten metal flowing from pool center to outer by the increasing of heat input and temperature gradient in molten pool.This faster flow drives molten metal to weld toe and avoid undercut, which is the main mechanism for restraining undercut.Furthermore, the experiential formula to undercut critical speed of hybrid welding and the optimal adjusting range of arc voltage were also obtained.