A refractory material's one that retains its strength at high temperatures. ASTM C71 defines refractories as "non-metallic materials having those chemical and physical properties that made them applicable for structures, or as components of systems, that're exposed to environments above 1000 °F (800K, 500 °C)". Refractory materials are used in linings for furnaces, kilns, incinerators and reactors. They're also used to make crucibles. Refractory materials Refractory materials must b… (More on Refractory)