The radiation properties of technologically important metallic materials are required for the calculation of heat transfer and pyrometric temperature measurement. Given the conditions in modern heat-treatment plants, spectral emissivities of bright metals in the temperature range 200 - 1200 ℃, wavelength range 0.8 - 16 μm, and in protective atmospheres must be known. A measuring apparatus with the desired parameters was constructed which allows investigations on nearly all metals with bright surfaces. Several steel grades and nonferrous alloys were examined to determine the influence of different parameters such as measurement temperature, chemical composition, and surface roughness on the emissivities. Total emissivities which can be employed for heat transfer calculations were computed from the measured spectral emissivities.
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