Research On Numerical Simulation Of Cogging Process Of Large Size TC21Alloy Ingot

Large size titanium ingots usually have severe internal metallurgy defects, mennwihle the control of the suface defect and the make of the cogging processing parameters are tough matters. So the research on forging technologies is of great significance. In this work, TC21alloy was hot compressed in a broad range of temperatures, and the relationship between the flow stress and deformation parameters was studied; The high temperatrure forging process of TC21alloy ingot upset to pancake and the forging process from billet to forging with required square section were simulated and the influence of different cogging processing parameters on the quality of forging was analyzed to provide theory and guidance for the preparation of large size TC21alloy forging. The main conclusions are summarized as follows:(1) TC21alloy was hot compressed in a broad range of temperatures and the relationship between the flow stress and deformation parameters was studied to provide model to the simulation of cogging process.(2) The high temperature forging process of ingot upset to pancake is simulated. The influence of different strain combinations and friction on the effective strain and forged pancake during the whole process were analyzed and optimized. Strain combinations of40%+50%two-step forging can enlarger the strain homogeneity of forged pancake and the damage is the lowest.(3) The high temperature forging process from the billet with round section to forging with square section was investigated. During the simulation,the influence of different forging parameters, such as the anvil fillet, the relative feed and reduction on surface quality of heavy forging were analyzed and opitimzed.(4) The stretching process of forging with square section was simulated. The influence of the anvil width, the reduction and the reposition of the anvil during each pass on the forging interal quality were analyzed and abtain:The pores in the forging can close well when the anvil width ratio is0.6; When the stretching scheme that every process takes the similar reduction is matched with the anvil relocation scheme that each process takes1/2anvil, forging will have good quality.