METHOD FOR DETECTING METAL-IN STATE

摘要

PURPOSE: A method for detecting metal-in state is provided to prevent early operation of looper by detecting metal-in time from distance and speed between rolling rolls and memorizing roll force after completing roll shift, thereby accurately detecting metal-in even during rolling of thin strip. CONSTITUTION: In a method for detecting metal-in state of each stands in hot rolling facility comprising a plurality of rolling stands (F1-F7), the method for detecting the metal-in state comprises a step (S1) of checking whether the top end of strip is advanced into a cut point or not; a step (S2) of memorizing zero ton as memory roll force of stand F1 if the top end of strip is advanced into the cut point; a step (S3) of judging it as stand F1 metal-in if roll force detected in stand F1 is the same as or more than the reference range compared to the memory roll force; a step (S4,S5) of judging the metal-in state by comparison of roll force of stand F2 after memorizing actual roll force of the stand F2 as memory roll force at a stand F1 metal-in time point; a step (S6,S7) of judging the metal-in state by comparison of roll force of stand F3 after memorizing actual roll force of the stand F3 as memory roll force at a stand F2 metal-in time point; and a step (S8-S12) of generating metal-in signals for the rear end stand (F(n+1)) if the strip moving distance is the same or longer than a distance between the strip and rear end stand (F(n+1)) by calculating moving distance of the strip when front end stand (F(n)) (n is 4 to 7) is in the metal-in state for the respective stands (F1-F7).