Research On Solid Granules Medium Forming Process Of T-pipe

The T-pipe is widely used in many fields such as aerospace industry,marine industry,automotive industry,household appliances,etc.Traditional welding,casting,hot extrusion and other processes have long been unable to meet the increasingly diversified production needs.Using solid granules medium as an internal high-pressure expansion medium can meet the requirements of one-time forming of lightweight parts.The process greatly reduces the mold cost,ensures production safety,simplifies the process,and improves the quality of components,which is well worth promoting research.Therefore,combining the current needs of T-pipe and the advantages of solid granules medium forming process,this paper proposes the solid granules medium forming process of T-pipe.In order to verify the feasibility of the process,this paper carries out the analysis of forming principle,theoretical derivation,finite element analysis,establishment of response surface optimization model,process test verification and other research work successively.(1)This paper introduces the principle of T-pipe solid granules medium forming process in detail,combs out the whole process considerations,and analyzes the possible forms of defects during the forming process.The relationship between stress and strain in the deformation zone of the pipe is briefly deduced.The material properties of the pipe and the parameters of the solid granules medium are experimentally determined.Establish a suitable simplified finite element model of the T-pipe particle media forming process in ABAQUS.Compare the advantages and disadvantages of three different bulging forming methods: spontaneous bulging forming,axial force and internal pressure bulging forming and compound bulging forming.Finally,the T-pipe solid granules medium compound bulging forming with reasonable stress and strain distribution,high branch height and good wall thickness uniformity is selected.(2)The single-factor experimental method is used to investigate the effect of the individual variables on the quality of T-pipe forming.It is determined that the superiority of the scanned die surface as the surface at the transition round corner of the T-pipe female die.Initially,the velocity of punch movement,the friction coefficient,the slope of the axial punch,the counter punch’s pressure and the loading function and the end-face bevel angle are selected as the factors to be investigated.Among these factors,the lower of the friction coefficient is beneficial to the forming process,the counter punch’s loading function is preferable to choose the ladder loading.And the end-face bevel angle of 15°is preferred.The remaining factors are approximately determined by analyzing the stress-strain relationship,branch height and the distribution of pipe wall thickness.(3)The branch height and maximum wall thickness difference are selected as response values,combined with a user-defined evaluative function.The BBD experimental design method in response surface method is applied to construct the correct response surface model.The interaction between three uncertain factors: the velocity of punch movement,the slope of the axial punch and the counter punch’s pressure on the response value is analyzed.In order to obtain the desired response values,the optimal solutions of the three factors are solved.The complete loading path solution is eventually formed and input to ABAQUS simulation for verification.(4)A kit of T-pipe solid granules medium forming die is designed to conduct technological experiments.The experiments demonstrate the influence of different factors and the accuracy of the ideal loading path.The best factors are adopted to successfully manufacture qualified T-pipes.