High-temperature High-speed Hot Deformation Behavior Of Inconel625 Alloy And Optimization Of High-speed Extrusion Process For Tube Of This Alloy

Incone1625 alloy is nickel-base wrought superalloy which is based on solid solution strengthened precipitation ofγ' phase. This alloy is with high strength, high toughness, excellent anti-fatigue and anti-corrosion from low temperature to 980℃. This alloy is widely used for nuclear industry, aviation, space flight and petrochemical industry etc. as tube.Nickel-base superalloy ballet can hardly be formed by hot piercing. Hot extrusion process is the tendency to form superalloy tube. By increasing the extrusion speed, billet can be deformed into tube which meets the requirements in a short time at high temperature. In present the research of Incone1625 alloy concentrated in the corrosion resistance, wearing resistance, fatigue and so on. On the hot deformation behavior, especially under high temperature and high strain rate there are few report. Deeply understanding deformation of Incone1625 alloy under high temperature and high strain rate and establishing an accurate constitutive model is not only the key to improve the prediction accuracy of numerical simulation, but also the main basis to determine the parameters of hot extrusion process.The solution heat treatment experiment was used to obtain Incone1625 alloy with single austenitic phase. The rules of grain growth and grain boundary segregation dissolving were researched on the solution heat treatment process. The model of grain growth was established and reasonable method of solution heat treatment was found based on this experiment.The true stress-strain curves were obtained through the high temperature and high speed compression experiment. The errors in flow stress caused by thermal effect were corrected. Constitutive equation of Incone1625 alloy at high temperature and high speed was established by curvilinear regression method.The microstructure after deformation showed dynamic recrystallization (DRX) is the main reason leading to softening for Incone1625 alloy. Then the model of DRX evolution in the process of deformation was established. Based on the dynamical materials model (DMM) and plastic instability criteria of Prasad, the processing map of Incone1625 alloy was established. The processing map was analyzed with the microstructures observation of the deformed specimens. The results can optimize the processing region of fine grain.According to the research above, the high speed hot extrusion process of Incone1625 alloy was simulated by using DEDORM3D finite software. The optimized process parameter was brought forth by analyzing the distribution of temperature, effective strain and effective stress for billet and mandrel under different deformation.