电弧增材制造等离子体对熔积层热力作用的研究

Effect of Arc Additive Manufacturing Plasma on Heat and Force Transfer of Cladding Layer

采用COMSOL multiphysics软件建立了电弧增材制造电弧对熔积层的热力作用模型。选择基板和焊丝材料均为304不锈钢,保护气体为纯氩气,研究了熔积层总高度对熔积层表面热通量密度、压力分布、电流密度和电磁力分布的影响。结果表明,热通量峰值随着层高增大而增大,与无熔积层相比,20 mm层高下熔积层表面热流密度峰值增幅达136%。熔积层边缘处等离子体流速增大,产生低压区,最低压强随着高度增大而减小。由于熔积层的电导率高于电离氩气,电流优先经过熔积层,熔积层顶面电流密度显著增大。熔积层中的径向电流较小,而轴向电流在自感应磁场下产生了指向中心的电磁力。并且热流密度、压力分布,电流和磁场在熔积层高达到20 mm后保持稳定。

Using COMSOL multiphysics software, a thermo-mechanical coupling model of the arc additive manufacturing arc on the deposited layer was established. The substrate and welding wire materials were selected as 304stainless steel, and the shielding gas was pure argon. The influence of the total height of the deposited layer on the surface heat flux density, pressure distribution, current density and electromagnetic force distribution of the deposited layer was studied.The results show that the peak heat flux increases with the increase of the layer height. Compared with that of the non-cladding layer, the peak heat flux density of the surface of the cladding layer at 20 mm layer height increases by 136%.The flow velocity at the edge of the deposited layer increases, resulting in a low pressure zone, and the minimum pressure decreases with the increase of the height. Since the conductivity of the deposited layer is higher than that of the ionized argon,the current preferentially passes through the deposited layer, and the current density on the top surface of the deposited layer increases significantly. The radial current in the deposited layer is smaller, and the electromagnetic force directed to the center is generated with the axial current under the self-induced magnetic field. And the heat flux density, pressure distribution,current and magnetic fields remain stable when the deposited layer height reaches 20 mm.