플라즈마 키홀 박판 용접에서의 열 및 물질 유동

Heat and mass flow in plasma arc keyhole-welding of thin plate

본 연구에서는 플라즈마 키홀 용접 시의 열 및 물질 유동을 규명함으로써 용 접부 조직변화 예측과 더불어 용접부 형상설계, 열응력 계산 등의 기본자료를 제시하 여 전체적인 용접부 품질성능을 향상시키는데 목적이 있다.

Use of a plasma arc as the source of energy for penetration welding of thin plates gives rise to a cylindrical hole surrounded by the molten metal. Material moves from the front to the rear of the hole by flowing around the hole as the workpiece is translated relatively to the arc. Based on the finite difference method, three different computer models have been proposed for the steady state, two dimensional heat and mass flow during the plasma arc welding. In the formulation energy equation was derived by the energy blance method through the cell control volume, and all the governing equations derived for the fixed coordinates was translated for the moving coordinate system. The driving force for fluid flow being considered was only electromagnetic force. The calculated and measured molten poon and HAZ width were compared and better agreement was obtained for the models considering the keyhole effect.