Board thickness abnormal cause presumption manner null of tandem roller and tandem

摘要

PURPOSE:To estimate an abnormality in automatic thickness control in a tandem mill provided with plural AGC. CONSTITUTION:Plate thickness gages T/G mounted on the outlet side of a 1-st stand and on the outlet side of a 5-th stand detect deviation of plate thickness continuously at least for a prescribed time. A frequency analyzing device 70 analyzes the frequency component of a detected thickness deviation. A data base 76 stores the frequency of an eccentric roll to periodical plate thickness variation by eccentricity of the roll, etc., in accordance with the respective rolling roll etc. An abnormality estimating means 78 estimates the abnormality in the automatic plate thickness control by the frequency of each eccentric roll through analyzed frequency components.