Simulation Research And Technology Parameter Optimization For Rolling Process Of 2219 Aluminum Alloy Y-section Ring

In this paper,a large Y-section ring of 2219 aluminum alloy is taken as the research subject,and establishes a Y-section ring rolling finite element model.Aiming at the problem of defects occurring in Y-section ring which is possible to insufficient filling during the rolling process,the research is carried out from the aspects of coordinated control of roll system movement,geometric parameters of profiled section rings as well as rolling process parameters on the forming quality of rings,and the formation mechanism of forming defects.Moreover,using response surface method and weighted combination method to optimize it,in order to obtain a reasonable process parameter scheme to improve the forming quality of the ring.Finally,to sorve the blanking problem of ring blanks with profiled section sections,a double-station profiled section ring rolling process is proposed.In this paper,numerical simulation is used as the main research method,and the following works are carried out:(1)Based on the ring rolling forming theory,the mechanical and mathematical model of the Y-section ring rolling are established,the calculation formula of the limit guiding force of the Y-section is deduced,and the stiffness conditions of the ring rolling process are established;A mathematical model for the speed control strategy of the tapered roller as well as the force-position coupling motion control strategy of the guide roller considering the correction of the forward slip coefficient is established;In order to accurately control the coordinated motion of the roller system,the secondary development of Abaqus is carried out by using Fortran language,and a finite element simulation model of the Y-section ring is obtained.Furthermore,the high-temperature rheology curve,hightemperature elastic modulus and air-cooled surface heat transfer coefficient of 2219 aluminum alloy were obtained through thermal compression experiments,pulse excitation method and finite element method,in order to make the material properties and boundary conditions of the finite element simulation model more accurate.(2)Numerical simulation is used to compare the influence of different rolling passes on the ring forming quality,and it is concluded that the closed-pass rolling Y-section ring is the best.And the influence of the geometric parameters of the profiled section ring(the depth of the target groove section,the angle of the target groove section)on the filling of the profiled section ring and the rolling force and the influence of rolling ratio and core roll feed strategy(core roll radial feed strategy,ring growth speed,driving roll speed)on equivalent plastic strain,temperature distribution and rolling force during rolling of profiled section ring was studied by numerical simulation,it is concluded that with the increase of the groove depth of the target section and the decrease of the groove angle of the target section,the difficulty of filling the ring and the degree of insufficient filling increases.(3)The formation mechanism of Y-section ring forming defects is analyzed,and it is concluded that due to uneven force and unreasonable distribution of metal axial flow,the ring is prone to occur insufficient filling defects,and the method of optimizing blank section shape is proposed to suppress the defects;The response surface model of the quantitative relationship between the standard deviation of equivalent plastic strain,standard deviation of temperature,standard deviation of rolling force and the degree of insufficient filling of the profiled section ring and the groove geometric parameters,ring growth speed,driving roller speed and blank Angle of the profiled section ring is obtained based on the response surface method.Combined with the weighted group method,multi-objective optimization is carried out for the process parameter scheme of the ring with the groove depth of the target section of 80 mm and the groove Angle of 50°.The results shows that the standard deviation of equivalent plastic strain,temperature,rolling force standard deviation and degree of insufficient filling are decreased by 15.19%,13.10%,31.96% and 55.47%respectively after optimization.The roundness of the ring is better and the defect of insufficient filling is inhibited obviously.(4)The double-station special-shaped ring rolling process is proposed,and its finite element model is established,furthermore,the coordinated motion control strategy of the roll system is designed;Afterwards,based on this process,the rolling numerical simulation of the Y-section ring is carried out,and the evolution as well as distribution law of temperature and equivalent plastic strain in the rolling zone of the ring which occurs during the rolling process are also studied.It is concluded that at the end of stable rolling,the highest temperature of rolling area is the core,the closer the lower the temperature on the surface of the ring,the ring outside surface temperature minimum bottom corner position,the equivalent plastic strain at the center is small,and the plastic strain increases as the ring is closer to the surface.