Cu-ni-fe Alloy During Hot Deformation Behavior And The Hollow Spindle Upsetting - Perforation Extruded Tube Numerical Simulation

Cu-Ni-Fe alloy tube which is mainly producted by hot extrusion, cold-rolling and cold-drawing is the critical material for producing condensor. Because of lacking systemic experiment of the flow character of the deforming materials in the hot extrusion processing, the implement of technical process and the design of dies are usually finished by experiences and results in some flaws which can't be visualized and can't get full understanding. This paper research the hot deformation behaviors of Cu-Ni-Fe alloy adopting physical simulation, and simulate the processing of perforate extruding with hollow ingot based on finite volmue method(FVM).The true stress-true strain curves of BFe10-1-1 and BFe30-1-1 copper alloy are got under the thermal simulation experiment by the technique of Gleeble-1500. The results indicate: the true stress decreases with the increase of deformation temperature under the same strai rate, and as the strain rate rises, the true stress increases under the same deformation temperature. The Cu-Ni-Fe alloy presentes work-harding phenomenon under the low temperature and low strain rate. The true stress-true strain curves appear wave phenomenon under the high temperature and high strain rate, and the dynamic recrystallization character is obvious with the strain rate's increasing. The flow stress equations of BFe10-1-1 and BFe30-1-1 copper alloy under hot deformation are obtained which are described by Zener-Hollomon parameter with Arrhenius model. The temperature rise is obvious in the hot compression processing, the maximum temperature rise up to 27℃which is helpful to the dynamic recrystallization.The structure analysis indicates that the dynamic recrystallization degree raises with the deformation temperature rising and deformation degree increasing, the size of grain under annealing status is refined with the deformation degree rising under the same strain rate and deformation temperature, which is helpful to the subsequent cold forming of the Cu-Ni-Fe alloy tube.The Upsetting-Perforating extrusion technical process with hollow ingot for tube producing is proposed to reach the purpose of improving ratio of material utilization, increasing length of the tube, reducing extrusion force and saving energy, but there are some defects which generate in the production process, for instances, inclusion, lamination and eccentric, et al. In this investigation, basing on software platform MSC.SuperForge, a multi-stage simulation technology of Finite Volume Method (FVM) is usd to simulate Upsetting-Perforating extrusion for BFe10-1-1 alloy tube producing adopting hollow ingot. The flow law, the field of temperature, stress and strain of the deforming materials are obtained. The closing process of the internal wall of the hollow ingot is got, which can be used to explain the phenomenon that the oxide skin which belong to the internal wall of hollow ingot occludes into the wall of extruded tube. The upsetting ratio affects the formation of these defects obviously. The defects in the wall of hot-extrued tube can be avoided by modificating the strcture of hole forming pin.