熔滴对激光焊接匙孔与熔池影响的数值模拟

Numerical Simulation of Influence of Droplet on Keyhole and Molten Pool of Laser Welding

对不同尺寸的熔滴填充进入熔池后的匙孔三维形貌和熔池金属流动特性进行相应的数值模拟研究。数值模拟结果表明:熔滴在匙孔上方下落后填充进入熔池,该过程对匙孔的形态波动影响较大,熔滴尺寸较大时,匙孔深度的波动幅度较大。半径为0.9 mm的熔滴进入熔池后,匙孔前壁的液态金属由熔池上方向熔池下方流动的趋势更强烈,匙孔底部出现向下的流动趋势,该流动趋势与熔滴未滴入前的流动趋势截然相反;半径为0.6 mm的熔滴进入熔池后,匙孔前壁的液态金属流动趋势较为复杂,匙孔前壁上部出现由熔池表面向熔池下方流动的趋势,匙孔前壁中部出现由左向右的流动趋势,匙孔底部出现由熔池底部向上方流动的趋势。

In this study,the 3D morphology of a keyhole after droplets fill the molten pool and the metal flow behavior of the molten pool during the process of droplets of different size filling the molten pool by corresponding numerical simulation are studied.Numerical simulation results show that the droplets above and below the keyhole that fall into the molten pool have a greater influence on the morphology fluctuation of the keyhole.Larger droplets increase the keyhole depth fluctuation.After a droplet with a radius of 0.9 mm enters the molten pool,the tendency of the liquid metal on the front wall of the keyhole to flow from the top to the bottom of the molten pool is increased,and a downward flow trend is observed near the bottom of the keyhole.The flow trend before a droplet enters the molten pool is diametrically opposite.After a droplet with a radius of 0.6 mm enters the molten pool,the liquid metal flow trend in the front wall of the keyhole is more complicated,the upper part of the front wall of the keyhole has a tendency to flow from the surface to the bottom of the molten pool.The flow trend from left to right in the middle of the front wall of the keyhole and a trend from the bottom of the molten pool to the top of the bottom of the keyhole occurs。