Precise Forming Simulation And Process Optimization Design Of Large C-shaped 2A14 Aluminum Alloy Barrel

Aiming at the problems of instability and underfill defect in the rolling process of 2A14 aluminum alloy large C-shaped barrel,this paper systematically studies the motion feed strategy and control of each roll,the mathematical model of matching the tube growth and core roll feed speed,the metal flow law,the blank optimization design and the barrel forming quality by combining theoretical analysis and finite element simulation,and effectively solves the problems of C-shaped barrel rolling instability and underfill defect,It provides theoretical guidance for the precise forming and manufacturing of large C-shaped barrel parts.The main research results of this paper are as follows:(1)Based on the forming theory of ring rolling technology,the bite in and forging through conditions of large C-shaped barrel parts are explored,and the motion feed strategy of each roll is established.The reasonable value range of driving roll speed is derived to be 0.127～0.509r/s,and the reasonable value range of core roll feed speed is 0.43～1.83mm/s.Facing the needs of stable rolling forming,the closed core roll rolling and constant outer radius growth of tube parts are proposed,and the rolling strategy of variable core roll feed speed is deduced,which effectively ensures the stability of the rolling process of large C-shaped barrel.(2)The axial flow law of material volume and the deformation behavior of blank rolling are analyzed.It is proved that the main cause of underfill problem is that the overturning moment of the roll causes the bending deformation of the rectangular blank,resulting in underfill defect.In the rolling process,the axial upward and downward volume flow of the intermediate metal of the barrel is not enough to meet the required volume of the underfill part,resulting in underfill defect in the final formed barrel.Based on this reason,the solutions of rectangular blank and special-shaped blank are put forward.It is found that the rectangular blank with rolling deformation not less than 45% and the special-shaped blank with taper of76 ° have no underfill defect,and the filling effect is good.The actual rolling test shows that the rectangular blank with 45% deformation can effectively solve the problem of underfill defect.(3)The equivalent plastic strain diagram,temperature distribution field and rolling force curve with time of the rectangular blank scheme with45% rolling deformation and the special-shaped blank scheme with 76 °taper are compared and analyzed.Based on the fitting analysis of MATLAB software,the forming quality and rolling stability of the rectangular blank scheme before and after optimization and the rectangular and special-shaped two blank schemes after optimization are explored,The results show that the tube forming quality is better,the rolling process is more stable,and the forming result of irregular blank is slightly better than that of rectangular blank.(4)The effective plastic strain and temperature distribution as well as the influence law of distribution uniformity of C-shaped barrel rolling results under three different main roller speeds of 0.3r/s,0.35r/s and 0.4r/s and three different outer radius growth speeds of 3.5mm/s,4mm/s and4.5mm/s were investigated respectively.The main research results are as follows: the smaller the driving roller speed and the faster the outer radius growth speed,the more uniform the equivalent plastic strain and temperature distribution of the rolled barrel.Therefore,this paper optimized the optimal combination of forming process parameters with driving roller speed of 0.3r/s and outer radius growth speed of 4.5mm/s.