The Research On Process Parameters And Size Control Of Arc Addictive Manufacturing For Stainless Steel

Arc material manufacturing technology is an important research direction of metal 3D printing and its purpose is to produce complex structural parts quickly.The whole workpiece made up of weld has the characteristics of compact structure and high mechanical properties.The forming process of one-layer was studied.In the different ranges of parameters.the forming morphology was different,mainly including small rough forming under low current-high welding speed,incomplete fusion under low current-high speed of wire feeding,wide and flat weld line under high current-low welding speed-high speed of wire feeding and forming perfect under other parameters intervalFirstly,single and multi-layer single pass forming processes are studied.The shape and precision of different parameters were studied,and the matching range of process parameters was established.The size deviation of arc starting point and arc ending point was analyzed and the dimension control strategy was proposed.For the straight wall body,we took the reciprocating packing method as the forming size in the arc starting point is large and the forming size in the arc ending point is small.At the same time,the current and wire feeding speed were reduced and the welding speed was increased on the arc starting point,while the feeding speed was increased the and the welding speed was reduced on the arc ending point.For the closed loop,a lap joint was formed and its length was 8mm.A model was developed between the size(width,height)and process parameters(stack current,speed and feed rate)for the control of dimensional accuracy.By means of orthogonal rotation combination test,the two regression models of size and parameters were obtained by MATLAB software.The results of the model analysis showed that the influence of the parameters on the layer width was:welding speed>wire feeding speed>stack current.The influence of the parameters on the size was:wire feeding speed>welding speed>stack current.The size can be controlled effectively by adjusting the parameters,and the purpose of optimizing parameters can be achieved.Then,the microstructure and mechanical properties were studied.It is found that it is composed of austenite and a small a little ferrite.Its tensile strength is about 510MPa,and in the vertical direction,it is higher.The stress distribution has the obvious law:in the height direction,the highest and lowest got high hardness,the middle part of the hardness is low;in the width direction,both sides of the hardness is low and in the center of the weld the hardness is high.Based on the plasma arc increasing material manufacturing system,the shaping strategy of a complex annular shell was raised.The forming of the workpiece was completed by the robot,and its error is low.The maximum relative error was 5.37%and the maximum error value was 0.22mm.Deposited efficiency reached 0.197kg/h.