| 摘要 |
PROBLEM TO BE SOLVED: To provide a cooling method for steel which has excellent cooling capacity and no problem to the surroundings and improves the profitability by executing the cooling while supplying an endothermic type modified gas into fluidized bed composed of solid fine grains. SOLUTION: While supplying the endothermic type modified gas into the solid fine grains, the cooling of the steel is executed. Since the endothermic type modified gas utilizes gas produced from a gas modifying furnace attached to a heat treatment apparatus, the preparation of gas generation and supplying device, etc., for executing the fluidization of the solid fine grains are not necessary, and thus, this method is profitable. This endothermic modified gas contains of about 35% H2 gas besides about 40% N2 gas and has excellent cooling effect in comparison with only N2 gas. Further, as the solid fine grain, ceramic fine grain is used and therein, alumina is very desirable material because this has chemically and physically stability and high hardness and high sp. heat besides high heat resistance. Then, it is desirable that the gas flowing speed in the fluidized bed is 5 times to 30 times of the min. fluidized flowing speed.
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