METHOD AND DEVICE FOR AVOIDING ABNORMAL ROLLING STATE IN TANDEM MILL

摘要

PURPOSE: To automatically avoid the unstable phenomenon of operation such as the variation in thickness and defects in shape of a product by judging the abnormal state of a rolling mill, estimating the factor of occurrence of abnormality and automatically correcting the state of control based on the estimating result. CONSTITUTION: The high-speed Fourier transformation of the thickness on the outlet side of the rolling mill 1 and time series data of the variation in interstand thickness and variation in interstand tension is executed with a frequency analyzer 10. The abnormal state of each measured value is judged according to the difference between each power spectrum and each threshold value determined from the present rolling speed with an abnormal rolling state judging device 11. The factor of the occurrence of the abnormal state and its degree are estimated from the degree of coincidence of the mutual juged results of abnormality and each power spectrum of the variation in the thickness on the inlet side and variation in rolling load and rolling speed with an abnormality occurrence factor estimating device 12. Control function that is the object of excess and deficiency of the state of control is judged from the rule of thumb with a control-state correcting/judging device 13. A control parameter or a control signal command value of the object control function is corrected with a rolling controller 14.