| 摘要 |
PROBLEM TO BE SOLVED: To propose a method and device for measurement of an oxide film thickness on the surface of a steel plate, capable of performing an accurate on-line and continuous measurement of the film thickness of an iron-based oxide formed on the surface of the steel plate, from outside a heating furnace being far from the steel plate.SOLUTION: The surface of the steel plate is irradiated intermittently with infrared light. When irradiated with the infrared light, the energy being the total of spontaneous light radiation energy radiated from the surface of the steel plate and reflected light energy of the radiated infrared light from the surface of the steel plate is detected in two different infrared wavelength bands. When irradiation with the infrared light is intercepted, only the spontaneous radiation energy from the steel plate is detected likewise. Out of detection values detected by the intermittent irradiation with the infrared light, the detection value detected upon interception of the infrared light is deducted from that detected upon irradiation, so as to calculate the reflected light energy. As to the calculated reflected light energy, the ratio between the energies in the two different infrared wavelength bands is computed on the entrance and exit sides of the heating furnace, and the ratio between them computed on these sides is computed. |
