PURPOSE: To restrain the generation of a scale pattern of controlled rolling material by regulating a temperature controlling time to the outside of a specific curve in accordance with the starting temperature of temperature control at the time of cooling during the temperature control of controlled rolling.
CONSTITUTION: After rolling a thick steel plate in an austenite recrystallization region; temperature control is started from the plate temperature at the time of the completion of rolling in a recrystallization region, in case of restarting the controlled rolling in an austenite unrecrystallization region higher in temperature than an Ar3 transformation point or a region extending to an austenite- ferrite two phases region. The rolling is restarted after setting the starting temperature and the successive time of temperature control to the outside of an oblique lined region surrounded by a characteristic curve of scale stripping relating to time and temperature, shown in the figure. Accordingly at the outside of the region, a secondary hard-to-strip film is uniformly formed on the whole surface of the plate, and the generation of scale pattern is effectively restrained.
TARUI RIYOU
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