The Numerical Simulation And Experimental Research Of Flexible Rolling And Extrusion Compound Forming

Hollow shaft parts has been widely used in auto and machinery industry. With the developing trend of small batch and more specifications, the research of new flexible efficient forming process becomes more and more particularly urgent and necessary. This research subject based on the project of the hollow shaft parts flexible rolling extrusion compound forming mechanism of the simulation and experiment research, which is supported by Natural Science Foundation of China. The thorough research of the flexible forming extrusion compound process has been done.In this article, this process was analyzed by numerical simulation and experiment. The finite element model of the process was established. Several key issues like the law of material flow conditions, the rolling condition, the damage evolution of the center, and the stress of the piercing plug were studied. The experimental device was designed, the hot rolling experiments was completed, and the preliminary experimental results were obtained. The results of the study deepened the recognization of this new technology, which has certain reference significance for the chosen of parameters and design of experimental facility.In attention to analyze the rolling condition, the relationship between the friction coefficient and unilateral reduction, nip angle, the head angle was obtained by numerical calculation, these results can provide theoretical bases for simulation calculation and the chosen of process experiment parameters. The flexible rolling forming was carried out by numerical simulation software Deform based on Oyane fracture criterion, the shear friction model,2d and3d simulation analyses. The damage evolution of the solid bar and tube billet forming was obtained. The pierce plug is best to be arranged in the front of the roll to improve the stress. With a series of simulation calculation, the process and mechanical parameters were obtained. It can provide experimental institutions for strength and stiffness design.Based on the experiment facility of flexible rolling, the clamping device was designed, and the hot forming experiment was done. The simulation results were verified With different process parameters, the law of the heart puff was studied, when the section shrinkage is between0.2and0.38, the heart puff won’t occur, rolling for more times is conducive to the generation of crack, the bigger the unilateral, the more prone to heart puff. The macro cavity of the center is star shaped crack. When the macro cavity was formed, to feed the pierce plug it is liable to form epicanthal folds. So the feeding chance is best to forestall the generation of the macro cavity.