| 摘要 |
PURPOSE:To improve respondence of temperature control in an annealing furnace, by installing plural heating devices each having different heating velocity to the heating zone and soaking zone of the continuous annealing furnace, and temporarily heating a strip at the time of abnormal operation. CONSTITUTION:A radiant tube heating device 7 whose heating velocity is, for example, <=15 deg.C/sec. is installed to a heating furnace 1 and/or a soaking furnace of a continuous annealing furnace, and an induction heating device 9 whose heating velocity is, for example, <=50 deg.C/sec. is installed to the outlet side, central part, or inlet side of the heating furnace 1. In the early stage of heating during the course of operation, the normal heating is performed by, for example, a radiant tube 7, and, when a command that the strip temperature or the line speed is to be changed is received, the output of the induction heating device 9 is rapidly increased and the strip temperature is raised in a short time. After that, the ouput of induction heating device 9 is gradually lowered until the normal heating is achieved. In this way, controllability of temperature and productivity of the strip are improved. |
