| abstract |
When the absolute value of the difference between the temperatures of the steel materials SM measured by the radiation thermometers (20a, 20b) is equal to or higher than a predetermined temperature, the scale composition determination device (10) determines that Fe 2 O is formed in the outermost layer of the scale (SC) 3 , otherwise, it is determined that Fe 2 O 3 is not formed in the outermost layer of the oxide scale (SC). |