Study On The Forming Characteristics And Microstructure Properties Of Bypass-Current Wire-Heating PAW On Additive Manufacturing

Compared with the traditional processing methods,arc additive manufacturing technology can be directly make the shape that we want,can improve the design flexibility,enhance the complex parts manufacturing capacity,known as "transformative" low cost,short cycle,high performance,"shape control/performance control "integrated manufacturing technology,is expected to replace the traditional mold,forging and other processing technology to manufacture metal parts.In this paper,a new technology of Bypass-current wire-heating plasma additive manufacturing is proposed.On the basis of constructing the test device,the experiment of Bypass-current wire-heating plasma additive manufacturing is first carried out,and the influence of process parameters on the forming of the material is studied,determine the best range of process parameters,and then under the best parameters carry on the additive manufacturing.After the determination of the optimum process parameters,the relationship between the parameters and the droplet transfer were studied.The influence of start arc and stop arc on the forming and the control method were studied.Further,the additive manufacturing experiment of the rotary body,the inclined wall structure,the copper and the steel-copper composite joint was carried out,stable and flat forming was obtained.Then,the structure of the straight wall was selected,and the metallographic specimen and the tensile specimen were prepared.The microstructure and morphology of the joint were analyzed by metallographic microscope and universal tensile tester,microhardness tester and scanning electron microscope.Fracture morphology observation to verify the feasibility of this process,and analysis of the impact of additive manufacturing on the organizational performance.Finally,the stress field and the strain field of the traditional plasma additive manufacturing and bypass-current wire-heating additive manufacturing were analyzed by ANSYS software,and the advantages and disadvantages of the two methods were analyzed.The results show that the parameter matching has a great influence on the appearance of the shape,and the parameter matching affects the droplet transition,and it is prone to collapse in the case of large droplet transition.The components produced by the bypass wire-heating plasma arc reinforcements have a more dense microstructure than ordinary 304 stainless steel.Fracture morphology shows that the material has a large number of dimples,the fracture form is ductile fracture.The results of welding simulation show that the stress and deformation of the 40 layers by plasma surfacing are larger than those of the bypass current wire-heating plasma.The displacement field has similar results.Bypass wire-heating plasma arc welding not only has a high fuse efficiency can also reduce the heat input and welding deformation,etc.It is a stable and reliable way to additive manufacturing,and greatly increased the efficiency of the material additive manufacturing,with a larger practical application prospects.For the development of additive manufacturing to provide a new process.