METHOD OF MANUFACTURING HOT ROLLED STEEL STRIP

摘要

PROBLEM TO BE SOLVED: To provide a method for stabilizing the rolling of hot rolling equipment having a constitution which cools a steel strip by a quenching device arranged at the outlet side of a finishing mill, and for improving the quality of a steel plate.SOLUTION: A method of manufacturing a hot rolled steel strip comprises: pinch rolls 155, 159 arranged at the outlet side of a hot rolling mill 151; an immediate quenching device 153; and a down-coiler 160. The manufacturing method also comprises: a first step of controlling the speed of the pinch rolls with a value obtained by adding a prescribed lead speed to a moving speed of the steel strip as a speed command; a second step of controlling the current of a motor of the pinch rolls, so that the tension of the steel strip at the inlet side of the pinch rolls may be a desired value; a third step of controlling the tension of the pinch rolls, so that tension measured by a tension detector 157 may be a desired value; a fourth step of calculating a value corresponding to a current command to the motor for driving the pinch rolls as a speed correction amount, and controlling the speed of the pinch rolls with a value calculated from the moving speed of the steel strip and a speed correction amount as a speed command; and a fifth step of controlling the speed of the pinch rolls with the moving speed of the steel strip as a speed command.