Finite Element Simulation Study On Tube Spinning Process And Texture Evolution Of TC21 Titanium Alloy

Titanium alloy tubes are a kind of important component in aerospace applications,which is usually formed by strong spinning(The surface of the workpiece is reduced in thickness by the rotary wheel and rotates along the mandrel axis).With the increasing requirement of integration and thin-wall lightweight of titanium alloy tubes in aerospace,the deformation degree of titanium alloy tube components formed by spinning is more and more large,which not only brings difficulties to the spinning process of titanium alloy tubes,but also causes strong texture orientation and anisotropy in the components,thus affecting the service performance of tubes.In this paper,the spinning process and texture of TC21 titanium alloy tubes are simulated and optimized by using the finite element simulation software ABAQUS.According to the spinning process of the tube,a finite element model is established,which is in accordance with the actual production process.The constitutive equation established by TC21 titanium alloy thermal simulation compression experimental data is imported into the finite element model.Through the numerical simulation results and analysis,the influence of spinning process parameters on the stress and strain of the blank in the forming process of TC21 titanium alloy tube is studied and optimized Spinning process parameters.The results show that the maximum equivalent stress decreases with the increase of spinning temperature.Spindle speed has no significant effect on the equivalence of force and strain,but can affect the billet wrinkling and roundness accuracy of outer diameter.During the spinning process,the two factors that had the most significant influence on the billet were the feed speed and the thinning rate.The increase of the feeding speed or the thinning rate would lead to the increase of the maximum stress area and strain peak value,and the most serious uplift defects were found when the feeding speed was 2.5mm/s and the thinning rate was 25%.Considering the forming quality of TC21 titanium alloy tubes,the spinning temperature 860℃,feed speed 1mm/s,spindle speed 4r/s and thinning rate 20% are suitable.The secondary development of the finite element simulation software ABAQUS was carried out,the crystal plasticity theory was embedded in the user material subroutine UMAT,and the secondary development of the ABAQUS was used to perform the spin-texture finite element numerical simulation.The results show that the spinning texture of the TC21 titanium alloy cylindrical part mainly includes four main components,which are the basal texture,the prismatic texture,the pyramidal texture and the silk texture.By increasing the feed speed,spindle speed and thinning rate all promote the formation of the basal texture,the pyramidal texture and the silk texture.Increasing the spinning feed speed of the tube spinning,the spindle speed and the thinning rate will increase the texture strength.The maximum texture strength is reached when the spindle speed is5r/s,and it is found that the increase in the thinning rate will also make the position of the strong point of texture changes.