Experimental Study On GMA Arc Additive Process Of Layered And Overlapping Structure

Based on GMA arc additive manufacturing technology,this paper imitates the "brickmud" structure of natural shell and pearl layer to prepare additive structures with excellent impact resistance.In this paper,ER130S-G high-strength steel is taken as the main research object to analyze the forming characteristics of additive process,trace microstructure and mechanical properties,carry out the research on the forming characteristics and size control of single trace deposition,multi-trace overlap process,and the microstructure and properties of layered overlapping structural parts.For high strength steel single pass deposition,a process parameter window was established and a well formed process specification interval was obtained.By using the Design-Expert software,the quadratic regression equation between the height and width of the deposited pass and the input variables was established by taking the wire feeding speed,arc motion speed and swing amplitude as input variables and the height and width of the deposited pass as output variables using the traditional quadratic regression method.It is concluded that the wire feeding speed has the most significant influence on the bead forming size.Experimental study on multichannel lap joint process of high strength steel,the effects of lap rate,cooling temperature and wire feeding speed on its forming,microstructure and mechanical properties were studied.The results show that the microstructure of high strength steel after lap joints can be divided into unheated areas mainly composed of acicular ferrite and granular bainite.The heating area is mainly composed of acicular ferrite + a small amount of granular bainite + lath martensite mixed structure.In lap rate was 45%,the cooling temperature of 150 ?,wire feed speed 6.0 m/min to get the best performance.Finally,the structural characteristics of natural shell and pearl layers are simulated to test the multi-layer and multi-channel layered overlapping structures of high strength steels and stainless steels with different ratio of layers.The microstructure of high strength steel was mainly martensite and bainite,and the microstructure of stainless steel was mainly austenite and ferrite.Compared with pure stainless steel,the tensile strength of high strength steelstainless steel laminated and overlapped structure is obviously improved along the pass and vertical pass.When the ratio of stainless steel to high strength steel is 1:3,the maximum tensile strength can reach 1119.54 mpa.By adding a certain proportion of stainless steel,the impact performance of the layered and overlapping structure of different materials can be improved both in front and side impact.When the ratio of stainless steel to high strength steel is 1:1,the impact resistance is improved most obviously,with the front impact toughness increased by 74.24% and the side impact toughness increased by 66.98%.