Research On Closure Of Void Defects In The Forgings

In this paper, numerical simulation and physical simulation were used to study the process of void closure in forgings during upsetting. The results of study deepened the understanding of the complicated problem. There is certain reference value to eliminate void defects in forgings by making use of reasonable processes.The MSC.SuperForm software was used in numerical simulation to investigate the upsetting process of 45 # steel cylinder forgings. By simulating the upsetting process of cylinder forgings with flat anvils, the internal distributions of stress and strain, and the effects of the ratio of height to diameter for forgings and friction conditions were obtained. The simulation results of the upsetting process of cylinder forgings with a single void with flat anvil indicated the shape variation of the void was sphere→ellipse→aperture in turn and at last the closure of void. The main influencing factors included the ratio of height to diameter for forgings and friction condition. A critical reduction in height formula for closure of voids was obtained by regression on the numerical result, reflecting the effects of main factors on the void closure.The process of upsetting of cylinder forgings with spherical anvil was numerically simulated using MSC.SuperForm software. According to the numerical results, the distributions of internal stress and strain were presented. The analysis results indicated that this new technique is important for ameliorating the inhomogeneous deformation and distributions of internal stress and strain. By simulating the process of upsetting of cylinder forgings with a single void with spherical anvils, the influence of the ratio of height to diameter for forgings and the ratio of spherical radius to cylinder diameter were obtained. The void which is located near the top or bottom surface of cylinder can be closed more easily by upsetting with spherical anvils than by upsetting with flat anvils.Investigation by physical simulation on the process of the void closure in a cylinder polycarbonate sample with an artificial void in the center during upsetting process was carried out. The process of void closure was observed directly. Compared with the physical simulation results, the numerical simulation with the same sample dimensions was verified to be reasonable.