Device Design And Experimental Study On Titanium Tube Extrusion-rolling Forming Process

In order to meet the requirements of titanium tube manufacturing in high technology field,a new titanium tube forming process,namely extrusion-rolling forming,is proposed in this paper,which combines the advantages of high forming efficiency and high spinning precision of three-roll oblique rolling,and realizes low cost and high efficiency pipe processing.In view of the difficulties of titanium tube machining,such as narrow process window and large deformation resistance,this paper carried out theoretical analysis,numerical simulation analysis and experimental research of titanium tube extrusion-rolling forming based on extrusion-rolling forming principle,which has practical application value for improving dimensional accuracy and mechanical properties of titanium tube.a new titanium tube forming process,namely extrusion forming,is proposed in this paper,which combines the advantages of high forming efficiency and high spinning precision of three-roll oblique rolling,and realizes low cost and high efficiency pipe processing.In view of the difficulties of titanium tube processing,such as narrow process window and large deformation resistance,this paper carried out theoretical analysis,numerical simulation analysis and experimental research on titanium tube extrusion forming based on the principle of extrusion forming,which has practical application value for improving the dimensional accuracy and mechanical properties of titanium tube.Firstly,the influence of roll shape on tube blank extrusion-rolling forming process was analyzed,the roll shape was designed,and the motion state of the roll was analyzed.The mathematical model of roll extrusion force was established based on Sims rolling theory,and the mathematical model of the projection area of the contact area between the roll and tube blank in the space coordinate plane was established according to the roll motion track.Secondly,the structure design of extrusion-rolling forming equipment is carried out.Based on the parameters of the tube billet and the specifications of the capillary tube,the key parts of extrusion-rolling forming equipment are selected through the mathematical model design of extrusion-rolling force,the three-dimensional model of extrusion-rolling forming equipment is established and manufacture the extrusion-rolling forming equipment.Then,the forming process of TA2 titanium tube was numerically simulated by finite element software,and the changes of stress,strain,temperature distribution and material flow of the tube blank were analyzed during the forming process.The influence of process parameters(roll feeding angle,roll revolution speed and tube blank advancing speed)on the stress-strain nephogram,dimension parameters,material accumulation and extrusion force of the tube after extrusion-rolling forming was studied.Orthogonal numerical simulation was carried out with appropriate process parameters,and the optimal process parameters were obtained based on the geometric dimension accuracy and axial section of the tube.Finally,the extrusion-rolling test of TA2 titanium tube was carried out on the self-designed extrusion-rolling forming equipment,and the TA2 titanium tube with good surface quality was successfully extruded.After extrusion-rolling forming,the diameter grain size of the capillary tube was significantly reduced compared with that of the original tube blank,indicating that extrusion-rolling forming had a grain refining effect on the tube blank.Tensile test at room temperature shows that the yield strength and tensile strength of TA2 titanium tube are obviously improved after extrusion-rolling forming.