| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for stabilizing material quality by canceling a gap between the material quality (mechanical properties) and a target value due to the variation of operation conditions in steps of manufacturing a steel plate. SOLUTION: This stabilization method comprises the steps of: previously determining a relational expression among content values of the base steel, the operation conditions in each step from hot rolling up to heat treatment of a final step side, and the material quality (yield strength and tensile strength), by analyzing past operational performance data; calculating a predicted value of the material quality from the relational expression, on the basis of the operational performance value in each step (preceding step) up to the heat treatment and a heating temperature (set value) in the heat treatment to be performed, determining the difference between the predicted value and the target value, and simultaneously determining a correction value of the heating temperature necessary for canceling the gap between the predicted value and the target value, before heat-treating the steel plate; and heat-treating the steel plate at the corrected and reset heat treatment temperature. Then, the stabilization method cancels the total influences of the material quality due to the variation of the operational performance in the preceding steps up to the heat treatment by the corrected heat treatment temperature, and consequently minimizes the gap between the material quality and the target value. COPYRIGHT: (C)2007,JPO&INPIT |
