Modelling temperature changes during hot working operations

Finite difference methods have been applied to determine radial heat transfer in round billets under conditions of hot extrusion, and in flat slabs during hot rolling. The principles of the computing procedures are outlined, together with the approximations adopted to eliminate iterative procedures and to obtain an accurate estimate of the surface temperature as well as of the temperature of the internal elements. In both situations, heat transfer coefficients at the surface have been determined experimentally and these coefficients can then be applied to other geometrical conditions to give excellent agreement with observation.