激光深熔焊运动熔池瞬态形成过程数值模拟

Numerical simulation of transient evolvement of molten pool in laser deep penetration welding

考虑到表面张力、浮力、液-固相之间内作用力、焊接速度、紊流、对流以及辐射等影响因素,建立激光深熔焊接过程运动熔池的数学模型,并对熔池的温度、流动、焊缝形貌的动态演化过程进行预测.结果表明,运动熔池形成过程中,变宽的趋势比拉长的趋势大,在宽度上达到最大值后继续拉长、变尖,达到准稳态;运动熔池上部分对流传热起主导作用,下部扩散传热起主导作用;Marangoni力是运动熔池上部变宽、拉长的主要作用力。数值模拟得到的熔池动态结果与实际拍摄的试验结果吻合较好。

The numerical model,including some effect factors such as surface tension,flotage,interaction force between liquid and solid,turbulent,welding velocity,convection and radiation,was founded for laser deep penetration welding processes,and the evolvements of the temperature,the flowing and the weld profile in the molten pool were forecasted.The results show that the trend of broaden in the molten pool is larger than that of elongate,the main heat transfer method in the upper of molten pool is the convection,but that in the lower of molten pool is diffusion,and the main force for the broadening and elongating in the upper pool is Marangoni force.The results of the high speed CCD camera and Katayama's X-ray image are well agreed with simulation results.