METHOD FOR PREVENTING HEAT BUCKLE AND DETERIORATED SHAPE IN STRIP IN CONTINUOUS ANNEALING

摘要

PURPOSE:To prevent the development of heat buckle and deteriorated shape by calculating elastic wrinkle developing limit tension as a function of temp. difference between center part and end part in a strip width and varying cooling blast rate or heating rate in the strip width direction so as to become temp. difference more than the above calculated temp. difference. CONSTITUTION:A model equation for the heat buckling developing limit tension of the strip 2 is set and the heat buckling developing limit tension value preset in each steel kind of the strip 2, size and line speed of continuous annealing is decided and set into a limit tension setter 6. To an arithmetic unit 7 of the above model equation, the limit tension value from the setter 6, yield stress from a yield stress arithmetic unit 5, strip temp. from a strip temp. meter 4-1 and previously informed conditional data for strip running are inputted. The operation of the above model equation is executed in the arithmetic unit 7 and the elastic wrinkle developing limit tension is outputted as the function of the temp. difference between the center part and the end part in the strip 2, and the cooling blast rate or heating rate are varied in the width direction of the strip 2 so as to become the temp. difference more than the above calculated temp. difference.