Simulation of hot rolling deformation at intermediate passes and its industrial validity

Thermo-mechanical behaviour of a rectangular bloom of micro-alloyed 38MnVS6 steel grade in a multi-pass hot rolling process using FORGE deformation simulation software was studied to predict the rolling load, torque, temperature distribution, metal flow behaviour, macrostructure, microstructural phase constitution and austenitic grain size distribution. The predicted load and torque values of the simulation matched with the experimental data evaluated using analytical equations. The metal flow behaviour showed that the strain penetration increased with degree of deformation. The corners have highest strain and the core has the least strain. The macrostructure of the experimental rolled bloom showed decrease in central porosity with increasing deformation. The predicted phase constitution at intermittent passes matches with experimentally determined microstructure. The prior austenite grain size validation showed a variation which was attributed to higher static recrystallisation at the billet surface. The surface temperature distribution measured in experiment using optical pyrometer showed variation with the predicted results and it was attributed to scale formation. Thus, this study has experimentally validated the effectiveness of deformation model in predicting the material behaviour in a hot rolling process.