# A Unified Analysis of Low-Power and High-Power Density Laser Welding Processes with Evolution of Free Surface

• 하응지 (한양대학교 대학원 기계공학과) ;
• 김우승 (한양대학교 기계공학과)
• 발행 : 2005.10.01

#### 초록

In this study, a unified numerical investigation has been performed on the evolution of weld pool and key-hole geometry during low-power and high-power density laser welding. Unsteady phase-change heat transfer and fluid flow with the surface tension are examined. The one-dimensional vaporization model is introduced to model the overheated surface temperature and 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, and the keyhole with thin liquid layer and the hump are visible at high-power density laser welding. It is also shown that the transition from conduction welding to penetration welding fur iron plate exists when the laser power density is about $10^6W/Cm^2$.

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