| 摘要 |
PURPOSE:To prevent for a steel plate to move in zigzag direction, by changing the line speed with the speed-time change rate obtained by a specified method in case of increasing line speed of an upright type continuous annealing furnace. CONSTITUTION:In upright type continuous annealing furnace, the steel plate 1 is suspendingly wound to a helper roll 6 to pass a heating zone 2, a soaking zone 3 and cooling zones 4, 5 to carry out annealing. In this operation, when the line speed is to be raised, the line speed-time change rate is found by the preestimating calculation for an axial temp. distribution of the helper roll in such a way that the max. temp. difference in the transient state between the center part of the helper roll 6 and the steel plate 1 is the limit value, or less, of the helper roll axial temp. difference corresponding to the heat crown limit value of the helper roll 6 which is the limit value allowing a stable movement of the steel plate 1. The set value of the line speed is changed by the obtained line speed-time change rate. Thus, the line speed is changed without the occurrence of zigzag motion of the steel plate.
|
