Abstract: A sight tube for an optical temperature measuring device suitable for immersion in molten steel comprises an elongated, cylindrical body having an optical sighting bore therein extending axially from an open end of the body to a closed end. The body is a carbon bonded alumina graphite material made from a mix consisting of, in weight percent, between about 5-45% graphite; between about 20-85% alumina; 0 to 15% anti-oxidant; and between about 3-20% phenolic resin binder. The mixture is isostatically pressed in the desired body shape and fired at a temperature in excess of 1400.degree. C. in a reducing atmosphere. The graphite is preferably a high purity flake graphite, greater than 99% pure. The alumina is preferably "brown" fused alumina grain having minimum amounts of volatile elements: sodium (Na), potassium (K), boron (B), phosphorous (P), sulphur (S) and chlorine (Cl). The sodium content, present as Na.sub.2 O in the alumina source is less than 0.05% by weight, and preferably no more than 0.02% by weight.

Abstract: The invention concerns a material for covering the metal contacting surfaces of casting elements such as slide gate valves and casting nozzles and shrouds to resist steel erosion and alumina deposition during the continuous casting of aluminum killed steel.It is comprised of a fused mixture of calcium oxide and zirconia, with a calcium oxide content of between about 20% and about 60% by weight and preferably between about 20% and about 50% by weight, the composition may include a binder producing carbon/carbon bonds by sintering. The material may also include a ceramic bond or may be applied as a fused layer by plasma spraying.

Abstract: A refractory liner composition which consists essentially of carbon and a composite selected from the group consisting of zirconia and O'-sialon and zirconia and silicon oxynitride.

Abstract: The invention is directed to a lining composition for submerged entry pouring nozzles and like shapes used in the continuous casting of metals, particularly aluminum killed, low carbon steels. The lining prevents harmful buildup of alumina and other oxides within the nozzle bore which may cause premature nozzle clogging. The nozzle liner comprises a carbon-bonded, SiAlON-graphite refractory material. Small amounts of antioxidants and additional amounts of less expensive refractory grain or powder are also added to dilute the more expensive SiAlON material.