Temperature effects of imperfectly formed metal-ingots in high temperature fixed point crucibles

This paper investigates, through thermal modeling the effect on the radiance temperature of imperfectly filled thermometric fixed points. A two dimensional axisymmetric thermal model was established and the effect on the radiance temperature of various ingot imperfections such as voids and cracks in different places and of different dimensions in the ingot structure was calculated. It was found that the radiance temperature of the fixed point is quite tolerant to even relatively large flaws in the ingot structure. Only when flaws of significant dimensions near the radiating back wall were introduced was the overall radiance temperature significantly affected.