| 摘要 |
PURPOSE:To reduce a cooling time considerably without generation of any thermal strain by controlling the quantity of heat rediation from the clearances between the ceiling and side walls of an annealing furnace according to the temp. of coils, and cooling the coils on the outside of the furnace after cooling the same down to an upper limit temp. for starting of the cooling on the outside of the furnace. CONSTITUTION:In cooling metallic coils 10 after heating and soaking the same in a batch type annealing furnace, the cooling state of the coils 10 is detected with a thermocouple 14, and a ceiling opening device 18 is driven by a controller 16 to control the opening in the clearances 20 between a ceiling 6 and side walls 4. Then the coils 10 are cooled mainly from an axial direction by the heat radiation from the furnace inside through the clearances 20 and the heat thereof is held while the relation between the walls 4 and the coils 10 is kept as it is. When the coils 10 attain the upper limit temp. of the primary cooling in such a state, the furnace body is removed, a muffle 12 is exposed into the atmosphere and the coils 10 are subjected to secondary cooling with the muffle 12. |
