PHYSICAL PROPERTIES OF REFRACTORY MATERIALS

The purpose of this program is to characterize and correlate the physical and mechanical properties of JTA graphite and from these data, determine its critical engineering properties. Three JTA billets were studied, two of 7 in. diameter by 6 12 in. long and one 14 in. diameter by 7 in. long. Examination of gross flaws and differences in density was done using radiographic methods. Densities of the three billets are above 3.00 gcc. Metallographic, x-ray, and mechanical measurements indicate that JTA graphite is anisotropic the with grain orientation is about twice as strong as the across grain orientation. Size effect studies indicate that a minimum 14 in. cross-section dimension is adequate for determining average mechanical properties. Studies were made using both flexure and tension measurements. Temperature and oxygen pressure have a great effect on the oxidation resistance of JTA graphite. The material appears to be more resistant at the higher temperatures.