3-D Simulation of hot forming and microstructure evolution

Stretch rolling is used for the production of a preform for subsequent die-forging of a connecting rod. A fully three-dimensional thermo-mechanically coupled FEM-simulation of a five-pass stretch rolling process has been performed. The influence was studied of various thermal and mechanical boundary conditions on the spatial strain and temperature fields developing. The results for the parameters strain, strain rate and temperature are used to predict the austenite grain size during the hot forming process by use of established recrystallization models. The calculated grain sizes are compared with those of formed components showing good agreement between experiment and numerical prediction.