Online forecasting manner null of hueraito crystal grain size

摘要

PURPOSE:To realize the control of the quality of steel products and the prediction of the quality thereof with high accuracy by measuring the conveying speed of the steel products and measuring the transformation rates in the plural longitudinal positions of the steel products thereby determining the progression rate of the gamma/alpha transformation of the steel products. CONSTITUTION:The progression condition of the transformation rate on a run-out table can be approximated by Y=exp{-[(k-t)/a]n}X100 when the gamma/alpha transformation rate is designated as Y%, the time elapsed after finish rolling as t(sec), constants by the chemical components of the steel plate are designated as K and (a) and the value depending on the progression rate of the transformation is designated as (n). The progression rate of the transformation can, therefore, be calculated from iVj=(Yj-Yi)/(tj-ti) if (n) is determined by substituting the measured value of the gamma/alpha transformation rate Y by the transformation rate detectors A1-A8 nearest the desired transformation rate range and the elapsed time (t) calculated from the conveying speed into the above-mentioned equation then determining the elapsed time ti, tj in the desired transformation rate range, for example, Yi, Yj by using such (n) value. The ferrite crystal grain size is predicted from the signals from the detectors A1-A8 and a conveying speedometer 24 and the information on the chemical components of the steel to be measured separately inputted into an arithmetic unit 22.