脉冲激光-电弧复合焊接镁合金过程中熔池行为与气孔产生的关系研究

Relationship between molten pool behavior and keyhole-induced porosity in pulsed laser-arc hybrid welding of magnesium alloy

摘要:

激光-电弧复合焊接镁合金过程中气孔是一种重要缺陷。本文针对复合热源焊接过程中熔池行为和激光匙孔引起的气孔之间的关系进行了实验研究。研究中重点考查了激光脉冲对熔池的冲击作用，匙孔的动态行为以及气孔的形成规律。研究结果表明激光脉冲的参数决定其对液态熔池的冲击作用，较强的激光脉冲作用可以有效抑制气孔的形成；液态金属的行为主要有匙孔行为主导；匙孔的尺寸和开-闭状态直接影响焊后气孔的形成；过高的激光脉冲功率会导致焊后气孔的形成；匙孔开口维持时间越长，焊后气孔数量越少。

Abstract:

The porosity is an important kind of weld defects in deep-penetration laser-arc welds. This paper gives an Experimental study on relationship between molten pool behavior and keyhole-induced porosity in pulsed laser-arc hybrid welding. In this research, the impact effect of laser pulse on the weld pool, and live behavior of the laser keyhole and the porosities in the weld were investigated in detail. Results show that the impact effects from the laser pulse depend on the laser pulse parameters and stronger impact effect helps restrain the porosity formation. The laser keyhole state dominants the welding pool behavior. The keyhole dimension and open-close state directly influences the porosity formation. Extremely high laser pulse power always brings about porosities after welding. Lengthening the laser keyhole opening time and giving the gas enough time to escape will be an effectively way to restrain the porosity.