| 摘要 |
PURPOSE:To prevent effectively the generation of meandering and heat buckling of a steel strip and to improve product quality in continuous annealing by adjusting the temp. at which the steel strip is led into and out of a horizontal type furnace. CONSTITUTION:The steel strip S is heated to some extent by passing through a preheating zone 21 and a low-temp. heating zone 22 in a continuous annealing installation for a cold-rolled steel sheet for deep drawing, etc. and is then introduced into a high-temp. heating and soaking zone 23 which is the horizontal type furnace where the steel strip is subjected to the prescribed heat treatment. The steel strip is in succession cooled down to a prescribed temp. by passing through the primary cooling zone 24 and is thereafter passed through the secondary cooling zone 25, overaging treatment zone 26 and tertiary cooling zone 27 of a vertical type furnace, by which prescribed material characteristics are given to the steel strip. The steel strip temp. on the inlet and outlet sides of the furnaces 23, 24 is controlled at about 780 deg.C to prevent the generation of the heat buckling. The passing speed is thereby increased and the productivity is improved. |
