薄板铝合金激光深熔焊熔池流动数值模拟

针对薄板铝合金激光焊接过程,采用有限体积法开展熔池流动研究.建立了三维焊接熔池流动数学模型,并采用高斯旋转体热源表征激光束的热作用.在考虑与不考虑表面张力作用下,分别计算获得了焊接温度场、熔池流场和熔池形貌.基于计算结果,分析了温度场云纹图、熔池焊接热循环曲线、熔池速度场分布多视图.最后进行相同参数下的激光焊接试验,基于观察获得的焊接接头形貌,综合分析了模拟结果和试验结果.结果表明,所建立的模型和模拟方法是合理可行的.同时考虑Marangoni对流作用所计算得到的熔池和焊缝几何形状更加接近实际焊接接头.

Molten flow simulation of laser deep penetration welding of aluminum alloys

For controlling size and distribution of oxide inclusions in weld metal,a method was presented in which an auxiliary electric field was applied between molten slag and weld pool metal with submerged arc welding so as to lead ion flow in molten by making use of auxiliary electric field.The preliminary experimental research was carried out with voltage supplied by direct current power supply as auxiliary electric field.The results show that when tungsten is used as cathode of auxiliary electric field,the electric conductivity of molten slag can be greatly improved due to lots of free electrons running into molten slag,and this makes a steady directional ion flow effectively inside the molten.By making complex particles ionization inside the molten, the auxiliary electric field applied between molten slag and weld pool metal impels both positive and negative ions to produce inverse flowers and results in electrochemical reactions at interface, thus reducing the opportunity of oxidation and this is helpful for inclusions to be broken and homogeneous.Meanwhile, under auxiliary electric field,the free oxygen ion in weld pool will migrate to slag-metal interface and be preferably combined with oxide forming elements in molten slag,then enter into slag.Therefore the oxygen content in weld metal can be effectively reduced.