Effect of Marangoni Convection on Welding Pool of Plasma Direct Metal Forming Finite Element Model

With considering the Marangoni convection in the molten pool on plasma direct metal forming process, a finite element model posed to describe and reflect the flow in the molten pool. Results of temperature distribution modeling prepared by plasma direct metal forming process of metal powders in an Ar environment were numerically obtained and compared with experimental data. Powders of Fe314 and base plates of R235 steel were taken as sample materials. In the experiment a multi-stream nozzle capable of delivering metal powder coaxially with the plasma arc was used. The model revealed that the velosity of the front part of the pool is a little slower than aft part. Marangoni convection reinforced the convection and enhanced the heat transfer. Profile of the model is the same as the experimental data. This allows us to conclude that the model can be applied for preselecting the process parameters. Keywords: plasma, rapid forming, temperature field, Marangoni convection.