Vesuvius Crucible Company

Dale B Hoggard

Han K Park

Mark K Fishler

Philippe Guillo

Quentin K Robinson

Fiona C Morrison

The present invention provides a composite pressure-sintered material comprising a continuous phase of hexagonal boron nitride and, dispersed therein, a second material comprising (a) at least one metal nitride selected from the group consisting of silicon, aluminium and titanium nitrides and (b) at least one stable metal oxide; wherein the amount of metal oxide is such that the second material does not contain more than 35% by weight of oxygen. This material possesses a low thermal expansion coefficient and therefore reveals good thermal shock resistance. Another characteristic of this material is its low wettability by molten steel which is thus responsible for excellent chemical resistance to liquid metal. Finally, this material is exceptionally mechanical wear resistant.

Composite material

A refractory material possessing excellent erosion, thermal shock and oxidation resistance, as well as resistance to oxide build up useful in continuous casting of steel for use in such articles as tundish shrouds, particularly for slagline sleeves, bore liners and upper seating areas in such shrouds, as well as for stopper rod noses. The material consists of the following by weight: (a) carbon, from about 4% to about 50%; (b) one or more members selected from the group consisting of zirconium di-boride and titanium di-boride in an amount of from about 10% to about 90%; and (c) one or more members selected from the group consisting of zirconia, SiAlON, clay, alumina, magnesia, silica, silicon carbide, silicon nitride, boron nitride, mullite and chromia in an mount of from about 10% to about 80%.

Erosion, thermal shock and oxidation resistant refractory compositions

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.

Refractory liner compositions

The invention is directed to improved carbon containing refractory compositions and sintered bodies made therefrom which are particularly resistant to slag and metal erosion and to thermal shock. This is achieved by combining grains or powders of SiAlON and/or silicon nitride with elemental carbon in the form of graphite, carbon black or charcoal. The particulate materials are mixed with a carbonaceous binder such as resin or pitch, pressed to shape and fired in a reducing atmosphere. Small amounts of antioxidants are also added to protect the carbon bond phase against slag attack. Additional amounts of a less expensive refractory grain or powder are also optionally added to the mix to dilute the more expensive SiAlON and/or silicon nitride.

Carbon bonded refractory bodies

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.

Growing community of inventors

Allegheny County, PA, United States of America

Dale B Hoggard