Modeling keyhole and weld pool dynamics of laser welding under variable ambient pressure

Abstract

It is widely accepted that evaporation induced recoil pressure plays critical roles in keyhole and weld pool dynamics during laser welding. Recent experiments by some of the authors have demonstrated that the partial pressure of surrounding gas could also contribute an important role to the dynamics of evaporation surface during laser welding under atmospheric pressure. However, most of mathematical models of keyhole and weld pool behaviours of laser welding did not include the effect of ambient pressure. In this study, we formulate a new mathematical model of recoil pressure which considering the effect of ambient gas pressure and adopt it to theoretically investigate keyhole and weld pool behaviours in laser welding under different ambient pressure, based on HUST’s comprehensive transient keyhole welding simulation code. Preliminary theoretical comparisons of three dimensional transient keyhole and weld pool behaviours during laser welding under variable ambient pressure are discussed. Some interesting phenomena which correspond well to recent experimental results are found. This research provides some theoretical backgrounds for applications of laser welding under different atmospheric pressure.It is widely accepted that evaporation induced recoil pressure plays critical roles in keyhole and weld pool dynamics during laser welding. Recent experiments by some of the authors have demonstrated that the partial pressure of surrounding gas could also contribute an important role to the dynamics of evaporation surface during laser welding under atmospheric pressure. However, most of mathematical models of keyhole and weld pool behaviours of laser welding did not include the effect of ambient pressure. In this study, we formulate a new mathematical model of recoil pressure which considering the effect of ambient gas pressure and adopt it to theoretically investigate keyhole and weld pool behaviours in laser welding under different ambient pressure, based on HUST’s comprehensive transient keyhole welding simulation code. Preliminary theoretical comparisons of three dimensional transient keyhole and weld pool behaviours during laser welding under variable ambient pressure are discussed. Some interesting ...