Sensitivity analysis to optimise the microstructural properties of an inconel 718 component manufactured by rotary forging

Microstructural behaviour of Inconel 718 using rotary forging as forming process is presented in this paper. This work is the continuation of a previous one, presented in ESAFORM 2012, in which the numerical model was described and previous results about microstructural behaviour were shown. Several simulations are carried out in order to investigate the effect of initial grain size, temperature and strain rate in microstructure. Experimental tests are done in order to validate the numerical results, analyzing the final microstructure. Preparation of the experimental equipment is shown: heating tool system, thermal isolation technique, tool design for the integration of the heating and the isolation system. Heat loss during the transfer operation between furnace and rotary forging machine is measured experimentally, in order to obtain a precise initial temperature value of the part at the beginning of the process. The experimental tests allow validating the simulation work, obtaining the real input parameters for the numerical calculation. Two ways of forming are obtained depending on the initial grain size. The optimal combination of the rotary forging process parameters listed above is determined in achieving a fine and homogeneous microstructure.