| 摘要 |
PURPOSE:To enable to be obtained a high quality steel sheet not hiving a high dispersion, by dividing quenching zone of continuous annealing furnace in two zones and carrying out overaging treatment providing the overaging zone between the above zones, and also, controlling passing time of the sheet to be annealed through the overaging zone. CONSTITUTION:The main body of continuous annealing furnace 1 is composed of the heating zone 3 of the sheet to be annealed 2, the uniform heating zone 4, the primary quenching zone 5, the secondary quenching zone 6 and the overaging zone 7 put between the zone 5 and 6. Moreover, the non-contact type durometer 8 is provided in order to measure the hardness of the sheet 2 sent out from the zone 6 continuously. Signal sent from the durometer 8 to the comparator 9, is compared with the signal from the aimed hardness set-up-device 10 and the hardness deviation signal DELTAH sent out. Next, the signal DELTAH is sent to the operator 11 and the correction amount of overaging treatment time DELTAt is operated based on the relation between the previously set signal DELTAH and overaging treatment time as shown in the figure 12. Then, the amount DELTAt is sent to the controller of driving motor of roll for the board 2 movement and is converted to the speed control signal DELTAV. Then, the above mentioned motor voltage is controlled by the treating speed value 14 and passing time of the zone 7 of the board 2 is controlled. |
