| 摘要 |
PROBLEM TO BE SOLVED: To uniformly and economically cool a high temp. steel without using any special equipment by cooling at a high cooling rate with cooling water after a red scale is uniformly generated on a high temp. steel surface. SOLUTION: After a red scale is generated on a whole surface of a high temp. steel to be cooled, water cooling is conducted. In order to generate the red scale on a steel surface, a chemical composition of the steel, for example, like increasing Si content, etc., is adjusted. A most suitable method to stably obtain the red scale is that an appropriate thickness of a normal scale is generated to the steel surface, hot rolling is conducted without removing the scale and is finished at about <=900 deg.C and then the red scales generated. A normal scale thickness of the steel surface before rolling is preferably in a range of 20-100μm. The red scale herein is of red color to yellow red color when observing the steel surface after hot rolled/cooled under visual observation.
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