Grain size prediction during open die forging processes

Abstract

One of the most important target parameters during open die forging is the microstructure, respectively
the grain size. This paper details different semi-empiric models that ultimately help to predict the microstructure
properties of a forged block. As a first step, trials in industrial scale were performed by Buderus Edelstahl
GmbH and attended by SMS Meer GmbH. The collected process data was used by the Institute of Metal Forming
(IBF) for the numerical analysis of the open die forging process and to validate the microstructure prediction
module STRUCSIM. The numerical prediction of the grain size shows a good agreement with the results
obtained from the metallography. In a second step models for the core fibre of a forged block were developed
at the IBF. The models use data from the online process measurement and simplified plastomechanical
interrelations for the calculation of equivalent strain and the temperature in the core of the forged part during
the process. With their results the microstructure in the core fibre of the workpiece can be predicted online.
The models are still in development and the most recent results will be presented in this paper.