THE TESTING OF SILICA BRICK

The Steger Load Test Apparatus. —Pressure was applied, in a granular-carbon resistance furnace, to the small test cylinders by means of a hollow carborundum rod. The temperature was read with an optical pyrometer sighted through this hollow pressure red. The volume changes were indicated by a pointer and scale and recorded by means of a rotating drum. (See Fig. 1.) Estimation of Quartz and Cristobalite in the Finished Br —The areas occupied by each type of crystal on the photomicrograph were determined with the aid of a transparent cross-section grating. Suggested Specifications for A1 Silica Brick. —Trust specific gravity not greater than 2.38; not more than 2% permanent Linear expansion after heating to 1600°C in one and one-half hours, and holding at that temperature for one-half hour; the amount of quartz land silicates) as determined by the grating method applied to photomicrograph should not exceed 15%.