A study of flatness defect in strip rolling occurred in tension unloading

Strips are usually fabricated under tension in tandem mill. They look flat if the tension is large and flatness control is performed via the measurement of transverse residual stress shape. Since compressive residual stresses are the main cause of geometric defect, actuator forces are changed in line to reduce or eliminate them. It is commonly supposed that strips buckle where residual stress field remain compressive. In this paper we show that this relation between residual stress fields and flatness defect is not always valid.