JPS5723036A - Method for cooling steel plate - Google Patents

Abstract

PURPOSE:To confine the deformation of a steel plate caused by ununiform cooling within a tolerance value by a method wherein, from temp. difference of the steel plate when the deformation thereof is reached to the tolerance value and each physical values at this time, thermal stress which is different corresponding to average temp. difference of the steel plate are measured and a temp. of a cooling roll is controlled so as to adjust said stress to a yield point of said steel plate. CONSTITUTION:Usually, both ends of the steel plate is fixed and extention DELTAL due to temp. difference DELTAT of both left and right end surfaces, strain epsilon and thermal stress sigma are respectively determined by formula I, II and III. Then, because a phenomena similar to the case of said model are partially generated also in cooling the steel plate by a practical cooling roll, the thermal stress generated in this time is made lower than a yield point of the steel plate to prevent the deformation of the steel plate. That is, the temp. difference DELTAT may be controlled so as to satisfy a condition of a formula IV. In a practical cooling roll, as said temp. difference, by using difference of a temp. of the cooling roll and an average temp. of the steel plate at a position where said steel plate starts contact against the cooling roll, the heat stress generated by said temp. difference is made lower than a yield point of said steel plate.