表面张力对激光深熔焊熔池流动的影响

为研究激光深熔焊中表面张力对熔池流动行为及熔池形貌的影响，获得活性剂对Q235低碳钢和304L不锈钢焊缝截面形貌的影响规律. 基于有限元计算软件Fluent，计算分析了激光深熔焊时表面张力在改变熔池流动行为中的重要作用. 结果表明，未添加活性剂焊接时，熔池液态金属的表面张力温度系数为负，熔池表面熔融金属以匙孔为中心由内向外流动，焊缝横截面形貌宽且浅. 添加活性剂焊接后，表面张力温度系数为正值，在熔池表面形成了由外向内的反向流动，形成了窄且深的焊缝形貌. 随表面张力温度系数绝对值的增大，表面张力变大，流体流动速度增大.

Effect of surface tension on flow in laser deep penetration welding molten pool

In order to study the effect of surface tension on the flow behavior of molten pool and the morphology of molten pool, the active agent test was designed, and based on the finite element calculation software Fluent, the effect of surface tension on the flow behavior of molten pool was analyzed. The results show that when the active agent is not added, the surface tension temperature coefficient is negative, the molten metal on the surface flows from the near keyhole to the edge of the molten pool, welds are wide and shallow. After adding the active agent, temperature coefficient of surface tension is positive, so that the vortex reverse, forming a narrow and deep weld. With the increase of the absolute value of the surface tension temperature coefficient, the surface tension becomes larger and the fluid velocity increases.