| 摘要 |
PURPOSE:To prevent the development of width shrinkage, heat buckle, etc., by making tension of steel sheet in high temp. zone horizontal furnace independent of the specific value or less from low temp. zone vertical furnace, at the time of annealing at high temp. in the vertical, horizontal and vertical furnaces while forming, in order of heating, soaking and cooling zones. CONSTITUTION:The steel sheet S introduced into the furnace, is executed to the prescribed heat-treatment during passing preheating zone 1, low temp. heating zone 2, high temp. heating soaking zone 3, high temp. cooling zone 4 and low temp. cooling zone 5, in order. Then, in the high temp. zone, occurrence of the development of width shrinkage or heat buckle is eliminated by controlling the added tension at <=0.6kg/mm<2> through pair of bridle rolls 6a, 6b. Further, construction of the furnace is horizontal, and the development of snaking or rough surface is prevented by arranging gas float supporting device, which supports by catenary under noncontact as supporting means for the steel sheet in the furnace.
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