Method for detecting abnormal vibration of rolling mill, apparatus for detecting abnormality of rolling mill, rolling method, and method for producing metal strip

A method for detecting abnormal vibration of a rolling mill that has a pair of work rolls and a plurality of backup rolls that support the work rolls, the method comprising:

• a collecting step of collecting vibration data of the rolling mill;
• a frequency analysis step of generating first analysis data by performing frequency analysis of the vibration data;
• a principal component analysis step of performing principal component analysis on the first analysis data by using reference data specified in advance on a basis of a normal state as a principal component and thereby generating evaluation data, which is a projection of the first analysis data onto the reference data;
• and
• an abnormal vibration detection step of extracting an outlier component from the evaluation data and the first analysis data and detecting an abnormality of the rolling mill from the extracted outlier component, wherein
• in the principal component analysis step, the principal component extracted as the reference data is set for each rolling speed in the rolling mill.