METHOD FOR DISCRIMINATING HIGH-TEMPERATURE RED HEATED MATERIAL

摘要

In heating a material radiant at high temperatures, such as, for example, a steel product, in a heating furnace, the material is charged into the heating furnace to heat. A discrimination mark is previously drawn on the surface of material to be discriminated on a portion readily watched from outside the furnace. A heat resisting paint sensitive to near ultraviolet rays of wavelength approximately 4358.ANG., which is comprised of (a) a manganese frit and a potassium silicate or (b) a zirconium frit and a potassium silicate is used to make the mark. The material which is radiant-heated in the heating furnace is discriminated from outside the furnace as being radiant by applying near ultraviolet rays of a high pressure mercury lamp thereto from outside the furnace to provide a sharp contrast between the material surface and the discrimination mark, for the discrimination of the mark from outside the furnace. The discrimination can be used to distinguish one material from another material being heated, or to discriminate a particular material. Preferably, the discrimination is achieved by photographing the interior furnace with a TV camera having a vidicon tube which has a high sensitivity to such near ultraviolet rays.