Research On Arc Additive Compound Forming Technology Of Superalloy

With the high-speed development of aeroengine its usage scenario gradually diversified,in the face of large complex structure forming manufacturing,the traditional processing method because of its low machining efficiency,the cost is expensive and the overall processing is difficult,difficult to adapt to the development of new type of aircraft engine gradually,but the emergence of arc added material manufacturing technology that makes it possible to processing and forming of large complicated structure.Arc additive manufacturing can greatly reduce the processing cycle due to the rapid integral forming of customized large and complex structural parts,and the additive materials can be modulated to meet the needs of multi-scene use of additive forming parts.However,arc additive manufacturing technology is evolved from welding technology in essence,and its development is restricted by low machining accuracy and internal defects of forming parts.How to improve the mechanical properties of arc additive forming parts and how to achieve precise shape control are the key problems that need to be solved urgently in arc additive manufacturing technology.Therefore,this paper focuses on the research of GH4169nickel-based superalloy arc additive composite forming technology.Firstly,the three-dimensional twinning dynamic simulation of temperature field and stress field in the TIG arc additive process of GH4169 nickel-based superalloy was realized by using the special finite element analysis software Simufact for Welding.The reliability of the simulation model was verified by heat source checking and experimental comparison tests.The evolution law of temperature field inside the cladding layer was explored,and the influence mechanism of thermal effect in arc additive process on heat accumulation and temperature gradient inside the forming parts was analyzed.Secondly,according to the actual arc additive process,the phenomenon of arc forming failure due to the collapse of the additive forming parts,the evolution law of the internal stress field of the forming parts was explored through demand traction,the formation reason and main influencing factors of the internal residual stress of the arc additive forming parts were analyzed,and the influence law of residual stress distribution on the deformation of the workpiece was explored.In order to further explore the forming characteristics of arc additive under different working conditions,the evolution law of forming path and inter-pass cooling time on thermal field was explored by changing the corresponding process parameters of numerical simulation.In view of the phenomenon that the stress concentration in arc addition process leads to the collapse of arc starting and extinguishing and thus can not be formed stably,the precise forming of welded parts is realized by using an external water-cooling device and coupling the optimal path and inter-pass cooling time,which provides a basis for forming process optimization and forming quality control.In order to explore the influence of high-frequency micro-forging impact strengthening technology on the mechanical properties and morphology regulation of arc additive forming parts,a composite forming system of high-frequency micro-forging impact strengthening for arc additive was first built to analyze the forming mechanism of high-frequency micro-forging impact strengthening.The effects of impact strengthening technology on grain growth characteristics,microhardness changes and tensile strength of multilayer stacked cladding layer were studied by designing five-factor and four-level orthogonal experiment.By comparing the macroscopic morphology of the samples without impact strengthening and the samples with impact strengthening,the effectiveness of the high-frequency micro-forging impact strengthening technology for forming part shape control was verified.Finally,in view of the problem that the mechanical properties of arc additive forming parts do not meet the standard of forgings and the use scenario is limited,the solution aging heat treatment system is introduced to explore the influence of different solution temperatures and solution time on the grain size,precipitated phase composition and mechanical properties of the additive forming parts.After solution and aging,the grain of the additive was refined,the precipitated phase composition was uniform and the mechanical properties reached the standard of forgings.