Forming Characteristics And Dimensional Control Of Thin-walled Components With Plasma Arc And Wire Additive Manufacture

Plasma arc and wire additive manufacturing,using plasma arc as the heat source and wire as the addictive material, fabricate high density and mechanical properties metal components rapidly. Production efficiency was improved and the core competitiveness was strengthen with shorter the production cycle. Based on robotized plasma arc and wire addictive manufacturing process technology, research on forming characteristics and critical dimension control has been carried out on carbon steel thin-walled structures in this paper.The effects of process parameters on forming appearance of the single-layer single-bead were studied. When the deposition speed was at 20～50cm/min range, a convex performance was observed on the layer width with the speed increases. Influenced by the mechanical limitations of the nozzle, layer width gradually approaches the nozzle diameter 3.2mm,while the deposition speed was increase.Straight wall addictive process test and critical forming dimension modeling and analysis with Matlab software was conducted. The results of single parameter impact analysis on layer height show that:the current reduction increases layer height, and this effect is more obvious when current is at 90-100A range than range 80-90A. The order of parameters effect on layer height is as follows:deposition speed> deposition current> layer interval. When layer interval is less than 60s,the effect of layer interval can be ignored. And the impact on layer width of deposition speed gradually strengthened as the current increasesMicrostructure and mechanical properties of the straight wall has been tested. The results showed that straight wall was composed of four typical microstructure grain zones,multi reheat layer microstructure zone consists of pearlite and fine equiaxed ferrite and pearlite region at the middle, top multi-junction configuration area and the top of acicular ferrite, bainite, sorbite and some a few overheated zone. The yield strength of all the tensile samples is over 340MPa and tensile strength is over 460MPa, equivalent to Q345 steel. belong to ductile fracture inclusions related. Straight wall hardness stabilized when the count of layer is over10.Based on robot-positioner plasma arc and wire addictive manufacturing system, a "single vector+slope" forming strategy was determined,and the robot program was made. A 3D rotation variable structure thin-walled cone was acquired and the average thickness is 5.175mm. process accuracy is about 0.2mm, material utilization is up to 96.5%.