On the emissivities of molten metals and iron alloys

Abstract

When temperatures are measured of molten metals and alloys by using a disappearing filament type optical pyrometer through the optical system, calibrations have to be made because the observed temperatures are always lower than the true temperatures. These calibrations consist of the emissivity and transmissivity corrections, since the emissivity depends on temperature, melt composition and measuring conditions, and the transmissivity changes according to the optical system used. The true temperatures of the melts were obtained by measuring the apparent optical temperatures of a cylindrical cavity in the magnesia crucible.