Effects of Transversal Temperature Distribution and Phase State on Strip Profile During Hot Rolling Process

Transversal temperature distribution and phase transformation of the strip steel in hot rolling process are analyzed by thermographic observations and thermal simulation tests. The effects of transversal temperature distribution and phase state on strip profile are investigated by finite element (FE) simulations, in which the material model of the strip steel is generated from the thermal simulation tests and a constitutive model. FE calculation shows that the decreased temperature at the edge causes smaller strip crown with the dual-phase state, while it leads to edge bulges in strip profile under single-phase state. With the convex temperature distribution, large strip crown is witnessed under dual-phase state; small crowns or even edge bulges appear under the single-phase state. For the concave temperature distribution, opposite conclusions are drawn compared with the convex temperature distribution. Measures to prevent edge bulges and control the strip crown are proposed and applied to industrial production. Reheating the edge area and assigning large target crown to the former stand of the finishing mill can avoid the edge bulges. Strip crown of the steel is more significantly affected by the bending force under dual-phase state than that under single-phase state.