| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for preventing fluctuation in the plate width in a continuous heat treatment facilities for estimating the width shrinkage not only in a stationary condition but also the width shrinkage in a non-stationary condition when shifting from a preceding steel strip to a succeeding steel strip. SOLUTION: A leveler is provided inside a continuous heat treatment furnace, the width of the steel strip is measured with a plate width meter disposed at the inlet side of the continuous heat treatment furnace, the width shrinkage of a measured part in the continuous heat treatment furnace is estimated, the width shrinkage is subtracted from the measured value of the width of the steel strip to estimate the width of the steel strip on the outlet side of the continuous heat treatment furnace, and the elongation rate of the leveler is adjusted so that the estimated width of the steel strip agrees with the target value. The width shrinkage is obtained on the basis of the shape of a thermal crown and the temperature of the steel strip by calculating the temperature of the steel strip in the furnace and the temperature distribution in each hearth roll in the axial direction, and determining the shape of the thermal crown of each hearth roll on the basis of the temperature distribution in the axial direction thereof.
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