| 摘要 |
PROBLEM TO BE SOLVED: To provide a cooling method and its apparatus by which the higher cooling effect than that of the conventional method can be obtained without oxidizing a steel strip and the consumption of hydrogen is reduced and a tramping or twisting phenomena are not caused. SOLUTION: In the forcible convection type cooling method for steel strip in a continuous heat treatment facility for performing the cooling by injecting cooling gas to the steel strip, the hydrogen concentration in the cooling gas injected to the steel strip, is 30-75% and satisfies formula (1). 0.001≤P<SB>H2O</SB>/P<SB>H2</SB>≤maximum value, either of [0.56×ln(T) -3.26] or [0.07]. Wherein, P<SB>H2O</SB>: partial pressure of steam, P<SB>H2</SB>: partial pressure of hydrogen, T: temperature (°C) of the steel strip. COPYRIGHT: (C)2004,JPO&NCIPI
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