Process modelling of flat rolling of steel

This paper describes the methodology of developing a process model using finite element method (FEM) based software, DEFORM-3D, to simulate hot rolling process of steel plates in industrial plate mill. Three dimensional thermal and plastic deformation models of plate rolling process were formulated in the software. In the preprocessing module of the software, objects like roll and slab were created using the respective dimensional data collected from the mill. Environmental conditions of the process were incorporated in the model. Flow stress, a material property required as one of the model inputs, was measured experimentally at different strain, strain rate and temperature in Gleeble-3500, a dynamic thermo-mechanical simulator. Empirical equations relating flow stress to strain, strain rate and temperature were developed by modifying the coefficients of the Norton - Hoff model equation. The coefficients of the equation were calculated from experimental data by error minimization. The modified flow stress equations were incorporated in the material properties module of the software. The post-processor was used for calculation of stress, temperature and roll force during rolling. The simulated results were validated with the measured data. There was a close match between the calculated and measured roll force. The prediction error was 3-5%.