| 摘要 |
PURPOSE:To provide an installation having improved thermal efficiency by using heating rolls for the secondary heating of the installation provided with a quick cooling zone, holding zone, secondary heating zone, overaging zone and secondary cooling zone in succession to a heating zone, soaking zone and slow cooling zone. CONSTITUTION:The continuous annealing installation is provided with the heating zone 1 for heating a steel strip A up to the prescribed temp. above the recrystallization temp., the soaking zone 2 for holding the strip at the temp. of the zone 1, the cooling zone 3 for slow cooling of the strip down to the prescribed temp. for starting the quick cooling, the quick cooling zone 4 for quick cooling of the strip with cooling rolls 5 down to the prescribed quick cooling end temp., the holding zone 6 for holding of the strip at the final cooling temp., the secondary heating zone 7 for heating the strip with heating rolls 8 up to the prescribed aging temp., the overaging zone 9 for holding the strip at the overaging temp. and the secondary cooling zone 10 for cooling down to the ordinary temp. The heating rolls 8 are heretofore not usable owing to the heat resistance of the rolls but in this part the strip is required to be heated in the low temp. part of, for example, 250 400 deg.C and therefore there is no problem of the heat resistance and the thermal efficiency is remarkably improved as compared to other systems.
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