Simulation Of Interlayer Cooling Time And Weld Forming Law In Magnetically Controlled Plasma Arc Additive Manufacturing

Plasma arc additive manufacturing has unique advantages in arc additive manufacturing technology because of the high energy density and free wire feeding of the arc,and is widely used in the manufacture of metal parts.However,the high deposition efficiency will increase the heat accumulation,which will easily cause the deformation of the formed parts and the unsightly forming surface.Therefore,in this paper,the external transverse magnetic field technology is applied to the plasma arc additive manufacturing to solve the forming problems caused by the heat accumulation.Based on finite element simulation software,the process of additive manufacturing is simulated and the temperature field and stress-strain field are analyzed,by the way the interlayer cooling time for subsequent tests is also determined,then a test platform is built to conduct a series of process tests to achieve good performance of the straight-walled body.The specific work of the paper is as follows:1.Establish a finite element model of magnetron plasma arc additive manufacturing,solve and determine the interlayer cooling time in subsequent actual experiments.Based on the finite element method to solve the temperature field and stress-strain field theory,the basic assumptions of the model are made,and the simulation model of magnetron plasma arc additive manufacturing is built through geometric model establishment,mesh division,heat source model selection and initial condition setting.And the calculation and analysis are carried out,and the variation law of the internal temperature field and stress-strain field in the process of additive manufacturing is analyzed and understood from the simulation results of Simufact welding software.In order to reduce the heat accumulation,the influence of the interlayer cooling time on the thermal cycle of the tracking point in the forming process is studied,and the interlayer cooling time is determined to provide guidance for the subsequent process tests.2.Build a test platform for magnetron plasma arc additive manufacturing.Through the independent selection of equipment and the structural design of the magnetron and wire feeding and clamping devices,a magnetron plasma arc additive manufacturing test platform is built to carry out process test.3.Carry out the magnetron plasma additive manufacturing process test to achieve good formation of straight wall bodies.A series of process tests are carried out on the platform.The plasma arc shape is observed by a high-speed camera,and the single-factor variable method is used to study the law of wire feeding speed,wire feeding angle,and wire feeding height on the formation of single-track deposition.In the bridging transition mode,the liquid molten pool is stable and the shape is well.The influence of the matching of the excitation frequency of the external transverse magnetic field and the wire feeding speed on the forming is further studied.The experiments show that different wire feeding speeds can be matched with the appropriate excitation frequency,which can not only ensure the stability of the forming process,but also improve the forming efficiency.Finally,a straight wall body is manufactured under this method.There are no obvious pores and cracks in the metallographic observation.The hardness test result is good and the overall shape is well.