자유표면변형을 고려한 저에너지밀도 및 고에너지밀도 레이저 용접공정 통합 해석

Abstract

In this study, a unified numerical investigation has been performed on the evolution of weld pool, key-hole geometry during low-power, high-power density laser welding. Unsteady phase-change heat transfer, fluid flow with the surface tension are examined. The one-dimensional vaporization model is introduced to model the overheated surface temperature, recoil pressure during high-power density laser welding. It is shown that Marangoni convection in the weld pool is dominant at low-power density laser welding,, the keyhole with thin liquid layer, the hump are visible at high-power density laser welding. It is also shown that the transition from conduction welding to penetration welding for iron plate exists when the laser power density is about 10^6W/㎠ .