Abstract: In order to obtain accurate flatness measurement, the calibration model as well as filter calculation of measured flatness signal are set by analysis of the principle and configuration of shapemeter roll. The model of thickness distribution across strip is set, from which the calculation precision of stress distribution across strip is improved by taking into account of thickness difference across strip. For the purpose of correcting measured flatness in edge of strip, the correction model of flatness measurement in edge of strip is established by analysis of the contact situation between strip and shapemeter roll. In case of transducer failure after long time running, the interpolation model of dummy segments is set. In addition, the transformation model of measured flatness from covered segments to several characteristic points is given so as to reduce complexity of data processing in flatness control system. The practical applications on the 1450 tandem cold mill show that this model is with excellent accuracy and provides a basis for flatness control.

Key words: Cold rolling, Flatness control, Flatness measurement, Shapemeter roll