Numerical simulation of hot die forging for IN 718 disc

Continuous improvements of properties for individual parts are indispensable for perpetual development of aircraft engines. Concerning turbine disc, numerical simulation of forging process is one of the most attractive tools to reduce the cost and time and to improve the properties and the reliability at the same time. In this paper, the hot deformation behavior of IN 718 superalloy has been characterized in the temperature range 900-1020 oC and strain rate range 0.001-0.1 s-1 using isothermal constant strain rate compression tests on process annealed material, with a view to obtain a correlation between grain size and the process parameters. Through a comparison study of two forging methods, temperature-field and strain-field finite element analysis modeling were established, and load-time curves were obtained for a turbine disc under routine and hot die forging process conditions. Results of numerical simulation show that compared to routine forging, hot die forging gives a decrease in total forging force, the temperature-field and strain-field of the turbine disc is more uniform. The effect of cold die on the microstructure is decreased notably under hot die forging condition. (AU) © 2010 by The Materials, Metals, & Materials Society. All rights reserved.