To provide an oxide film thickness measuring method for a steel sheet surface capable of measuring an applied amount of a solvent in an inlet side of a direct heating furnace, and an oxide film thickness on the steel sheet surface in an outlet side of the direct heating furnace, and capable of carrying out precise measurement, and an instrument therefor.
An infrared ray is emitted toward the steel sheet 1 in the inlet side of the direct heating furnace, to measure an intensity of a reflected ray thereof, an intensity of radiation light radiated spontaneously from the steel sheet 1 is measured in the outlet side of the direct heating furnace, and an intensity of reflection/radiation light composed with the radiation light radiated spontaneously from the steel sheet 1 and the reflected ray of the irradiated ray is measured by irradiating the steel sheet 1 with the infrared ray, to find at least one of the film thickness d of iron oxides generated on the surface in the steel sheet 1 and the applied amount W of the solvent applied onto the steel sheet 1, based on the intensity of the reflected ray, the intensity of radiation light in the same position where the intensity of the reflected ray is measured, and the intensity of reflection/radiation light.
COPYRIGHT: (C)2008,JPO&INPIT
Kiyoshi Yasushima
Souji Sasaki
Noboru Omura
Takanashi Norio
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