Two-dimensional temperature distribution of strip in preheating furnace of continuous annealing line

In this article, two-dimensional temperature distributions of the steel strip in preheating furnace of the continuous annealing line (CAL) are studied by the energy balance method with the aid of finite element analysis. The space of the furnace is first divided into several enclosures, in which the mechanisms of heat convection, heat radiation, and contact heat transfer between the strip and the rolls are taken into account. It is assumed that the furnace is already in the steady state. In other words, the energy remains balance within each enclosure and the temperature at each component is independent of time. In the present study, the surface temperatures of the rolls as well as the contact pressure between the strip and the roll are determined first by finite element analysis. The longitudinal and transverse temperature distributions of the strip are then calculated by using the method of energy balance. It is found that the strip exhibits a significant temperature rise after contacting with the roll. Moreover, the crown of roll has a significant influence on the transverse temperature distribution of the strip. The strip shows a non-uniform temperature distribution along the width direction with smaller magnitude at two sides in the preheating furnace.