M Ebrahimi - M. S. Student, Material Scince And Technology Department, Sharif University of Technology, Tehran, Iran
A Akbarzadeh - Assistant Prof. , Material Scince And Technology Department, Sharif University of Technology, Tehran, Iran

Accurate prediction of rolling forces as well as the dimentional variation of hot rolled sheets can be achieved by mathematical modelling of thermal and mechanical behaviour of material during hot rolling. The paterns of temperature, strain and the flow stress distribution are determined by heat transfer and plasticity models. In this work, a two dimentional heat transfer model is coupled with a simple upper bound model to calculate the roll presure ditribution across the sheet width. This is done by a 2D FDM which is utillized to solve the equation. The thermal model includes the conduction, convection and radiation before, during and after steady state rolling. The extracted model is unsteady state one and it is solved in implicit form. An upper bound velocity field is applied to explain material movement between the rolls and to calculate the strain rate and strain distribution at the roll gap. Finally, the pressure distribution along roll barrel is determined for rolls without crown by employing the proper boundary conditions. The results are compared with some measured data on a low carbon hot band rolling mill.

hot rolling, hot bands, finite difference method , rolling pressure, roll crown