Characteristics and prevention of thermomechanical controlled process plate deflection resulting from uneven cooling

Abstract

AbstractThe thermomechanical controlled process (TMCP) plates manufactured by this accelerated cooling process may have serious and complicated deflection problems resulting from uneven cooling and consequent thermal stresses. The deflections of TMCP plates were classified into first, second, and third deflections according to the stage at which they occur. Each type of deflection was analysed by applying thermal stress and elastic instability theory to the related temperature deviation. Accordingly, the cooling processes, such as top/bottom flow ratio, cooling water on/off timing, and amount of edge masking, were modified to improve the uniformity of cooling. In addition, a theoretical prediction model was developed which could estimate the deflections of plates during air cooling and after splitting into narrow strips, from the measured temperature distribution after hot levelling. Based on the result of this theoretical calculation, the requirements for stress relief treatment such as the cold levellin...