| 摘要 |
PURPOSE:To enable arbitrary setting of the temp. of a circulating gas by providing a cooler freely drawably to the circulation passage for the circulating gas formed in a furnace body and adjusting the drawing length of the cooler. CONSTITUTION:A band-shaped metallic material 6 is subjected to a heat treatment in a heating chamber 2, temp. varying chamber 3 and cooling chamber 4 of a floating furnace 6. Cooling of the material 6 in the temp. varying chamber 3 is executed by drawing out the cooler 13 forward from a housing case 12 by the shrinkage effect of a sealing material 16, engaging a heat insulating material 14 in the front end part with an engaging recess 17 across a suction passage 10A and shutting off the inlet of the case 12 by a heating insulating material 14' in the rear end part. The circulating gas is circulated in this state into the temp. varying chamber 3 by a circulation fan 18 to cool the material 6. The temp. varying chamber 3 is selectively set as a slow cooling zone or soaking zone by adjusting the drawing-out length of the cooler 13 in the case of slow cooling or soaking the material 6.
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