Abstract
Abstract
The deformation constitutive equation and the microstructure models in terms of critical strain, dynamic recrystallization, and grain growth for superalloy IN718 have been established based on the isothermal compression tests. Non-isothermal upsetting experiments have been carried out to refine and validate the microstructure evolution models. A processing map has been generated using the flow stress data obtained from the isothermal compression tests. According to the processing map, the optimum hot working parameters for superalloy IN718 have been obtained. The effect of process parameters on the microstructure development during the hot die forging of IN718 turbine disc have been investigated through coupling the microstructure evolution prediction system developed with a commercial FE software, MSC. Superform. To design the hot die forging of IN718 turbine disc, a uniform function of microstructure has been proposed as the goal function. On the basis of simulation results, the optimum hot die forging parameters have been obtained.