Study Of Technology And Mechanical Property On The Fabricated Fe25 Alloy By MPAW

With the development of rapid prototyping technology,using rapid prototyping to fabricating resin,wax and other non-metallic materials technology has become more and more mature.Researchers' vision also gradually turned to study on the metal parts directly rapid prototyping technology at home and abroad.At present,ripe relatively direct metal forming technology are mainly laser and electron beam which as the forming source of heat to fabricate metal parts,which have high density,good mechanical performance and high precision and have been applied in the field of aerospace and other high-end demand field.However,no denying that the expensive laser and the electron-beam which needs harsh conditions increased the cost of making the parts,therefore,to a certain extent,the development of direct metal forming and popularity is hampered by these factors.So some universities and companies began to look for low cost and high quality metal forming technology in the field of welding cladding.Among various kinds of 3d welding,Micro-beam Plasma Arc Welding(MPAW)with its better stiffness,strong stability,energy density focus,and the advantages of small heat affected metal rapid prototyping technology was introduced.This paper systematically researched the process from the line scan to face scan to body scanning in turn based on the independent build micro-beam plasma three-dimensional welding platform,and the mechanical properties of the forming parts and tensile failure forms were analyzed.First of all,the numerical model of molten pool was established,and And single channel single layer printing process were studied by Using the control variable method,Mainly studied the welding current,feeding rate and scanning speed and other parameters on the forming effect,and determined the best process parameters in the form of combination of macro and micro organization.Secondly,building overlapping model,research the process of surface scanning and analysis the cladding layers of tissue morphology and hardness under different overlapping rate,and the best lap rate was determined With the combination of theory and experiment.Then using the previous two part of the process parameters to study body scanning,to analyzing causes of various defects in the forming and optimizing the process.Finally,mechanical property on the forming metal parts in different scanning path was studied.The experimental results show that the influence law of welds about the process parameters is obtained through the study of line scanning.Best printing technology is welding current 30 A,scanning speed is 0.75 mm/s,feeding rate of 10 g/min,the arc column height is 10 mm;When the overlapping rate of the weld bead at 30%,we can obtain good surface quality and small and dense micro-structure.When printing in a small number of layer,reduced the thickness of the base plate can reduce the residual stress in the process of forming,obtained forming parts with less crack and inclusion.Micro-beam plasma three-dimensional welding Fe25 alloy has good mechanical properties,and the fracture mode of tensile samples is ductile fracture.