Refractory shape having an external layer capable of forming a layer impermeable to gases and process for its preparation
AssigneeVesuvius Crucible Company
InventorsEric Hanse, Phillipe Dumas
Life of this patent
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Abstract
The invention concerns a component for the pouring of steel that has a body (2) of a refractory material containing carbon. It has a layer (10) that covers the body partially or completely and is capable of forming a surface layer (10a) that is oxidized and densified and is impermeable to gases when it is brought to a temperature above 1000.degree. C. The layer (10) is comprised of a refractory material containing sintering precursors chosen in the group consisting of calcined alumina, reactive calcined alumina, silica fumes and clays.
Claims15
A refractory article for the pouring of steel, comprising a body of a refractory material containing carbon and one or more metal oxides, said article having a refractory layer integral with the body and covering molten steel contacting surfaces of said refractory article, containing one or more metal oxides, 4-9% by weight carbon and at least one sintering precursor, wherein said layer is adapted to form a densified, carbon free and gas impermeable surface when the layer is heated to a temperature above 1000.degree. C. in an oxygen bearing atmosphere such that the carbon in the layer is removed by oxidation along the surface to provide a porous refractory structure which is simultaneously densified by virtue of the sintering precursor.
A refractory article for the pouring of steel, comprising a body of a carbon bonded refractory material including alumina and graphite constituents, said body having an integral layer of a refractory material thereon covering molten steel contacting surfaces of said refractory article, the refractory material of said layer comprising a mixture of 80 to 90% by weight alumina;
- 2 to 10% by weight carbon;
- up to 5 weight % of one or more sintering precursors selected from the group consisting of calcined alumina, reactive calcined alumina, fumed silica and clays;
- and up to 5 weight % of one or more permeability reducing agents chosen from the group consisting of borax, silicon carbide, boron carbide and metallic additions including silicon metal;
- and wherein said layer is adapted to form a densified, carbon free and gas impermeable surface when said layer is heated to a temperature of above 1000.degree. C. in an oxygen bearing atmosphere.
Dependencies are inferred from the claim text.