Experimental and Computational Modelling of Temperature Gradients during Hot Rolling

摘要

During industrial production of hot strip, problems with cooled edges can occur. At low finish rolling temperatures, the microstructure of the material can be fully austenitic and the edges can display a partially transformed microstructure due to a temperature gradient over the strip width. So the edges could be rolled in the two-phase region of ferrite and austenite, whereas the centre is rolled in the austenitic region. For a proper prediction of the resulting microstructure and mechanical properties distribution, it is necessary to include the temperature gradient in the simulation of the transformation under a given deformation schedule. In this project the microstructure evolution in the final pass during hot rolling with cooled edges is described in a pilot-scale experiment. The transformation behaviour of the material is calculated by means of a semi-empirical transformation model with respect to the temperature gradient over the strip width.