| 摘要 |
<p>Indicator to demonstrate visually that ceramic body has been uniformly heated to a predetermined temp. comprises material which has burn-off temp. equal to required temp. Body is ceramic filter for molten metal, and at least one preheat indicator is located on surface thereof. Dots of indicator are pref. applied at 2 opposed corners or sides of body to show that the body has been uniformly heated. Indicator is pref. a dye which fades at the required temp. and esp. has burn-off temp. of 400-1200 deg.F, and is esp. aniline dye which is applied as 0.01-30 g/l aq. soln.</p> |
