Study On Microstructure Evolution And Arc Physical Properties Of 316L Stainless Steel With TIG Additive Manufacturing

With the development of industrial technology,additive manufacturing technology has its own place in aerospace,navigation,biomedical and other industries with its unique manufacturing process.The use of metal additive manufacturing technology has been able to produce stainless steel impeller parts with good performance.With the characteristics of high deposition rate,strong adaptability and low cost,arc additive manufacturing has been widely concerned in the field of large-scale complex and difficult to machine deformable components.TIG arc additive manufacturing is widely used in large-scale and small-scale manufacturing of complex structures in aviation,navigation,energy and other fields because of its good stability,no spatter and high-quality forming.In this paper,the physical characteristics and microstructure evolution of TIG additive manufacturing are studied,and the manufacturing system of TIG additive manufacturing is built.The forming process,physical characteristics and microstructure evolution of TIG additive manufacturing are discussed.The main contents of this paper are as follows:The proper process parameters of arc additive manufacturing are the premise to obtain the components with good performance.The current and droplet transfer form of the additive are important parameters that affect the stability of the arc and the shape of the component.In this paper,three different current sizes are used to test the additive manufacturing process,and the shape,arc transfer form and arc shape of the additive manufacturing under three groups of current are compared.Finally,the deposition current 200 A,deposition speed 250-260 mm / min,wire feeding speed200 cm / min,interlayer cooling are determined The removal time is about 60 s,and the transition form is the optimal parameter under the condition of bridging transition;In the process of TIG arc additive manufacturing,with the increase of the number of layers,the properties of the additive manufacturing arc also change.The spectral distribution and characteristic spectral intensity distribution of the additive manufacturing arc are obtained by the optical acquisition test system of TIG arc additive manufacturing,and the visual change trend of the additive manufacturing arc is obtained by analyzing the geometric shape of the additive manufacturing arc.Furthermore,the relative strength method is used to calculate the temperature of the arc center of the additive manufacturing,and the change trend of the arc temperature in the process of the additive manufacturing is analyzed.It is found that the temperature of the arc center of the additive manufacturing increases in the first five layers as a whole,and after five layers,the temperature of the arc center decreases slightly,and then stabilizes in a certain range.According to the characteristics of the heat flow distribution of the arc heat source,the change rule of the heat source in the additive manufacturing arc is analyzed.It is found that the additive manufacturing heat source increases with the number of deposition layers,the central temperature of the arc increases and radiates to both sides in Gaussian distribution.After five layers,the temperature distribution trend is stable in a certain range.The analysis of the physical properties of the arc in the process of adding material lays a foundation for the research of the heat input in the adding material component.During the process of adding material,each deposition layer undergoes repeated preheating,heating and post heating processes,and its structure change is determined by the heat input of arc and the heat process of workpiece heat dissipation.In this paper,the microstructure of the top layer in the deposition process of the additive manufacturing component is observed under the condition of non-equilibrium heat accumulation and heat accumulation equilibrium respectively,and the change behavior of the microstructure of the top layer in the multilayer deposition layer is discussed.Then,the microstructure of the whole additive manufacturing component is observed under the condition of non-equilibrium heat accumulation and heat accumulation equilibrium respectively,and the structure of different layers of the additive manufacturing is analyzed The microstructure of the whole part was obtained under different conditions.