| 摘要 |
PURPOSE:To prevent the generation of heat buckling of a steel strip and to provide an increase in passing speed and an improvement in productivity in continuous annealing by adjusting the temp. at which the steel strip is led into and out of a vertical type single-pass 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 introduced into the high-temp. heating and soaking zone 23 of the vertical single-pass furnace where the 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 then passed through the secondary cooling zone 25, overaging treatment zone 26 and tertiary cooling zone 27, by which prescribed material characteristics are given thereto. The temp. of the steel strip on the inlet and outlet side of the vertical type single-pass furnace is controlled at about <780 deg.C to prevent generation of the heat buckling. The generation of meandering the annealing furnace and the generation of flaws on the steel strip are thus prevented. |
