Erosion, thermal shock and oxidation resistant refractory compositions

A refractory composition consisting essentially of, by weight:

• (a) carbon from about 15% to about 25%;
• (b) zirconium di-boride from about 30% to about 40%;
• and 40%;
• (c) zirconia from about 30% to about 40%;
• and further including
• (d) boron carbide from about 1% to about 5%.

An article for use in casting molten metal wherein the article includes a molten metal contacting surface of a carbon bonded refractory composition for resisting erosion, thermal shock, oxidation and oxide build-up consisting essentially of, by weight:

• (a) carbon from about 15% to about 50%;
• (b) zirconium di-boride in an amount of from about 10% to about 75%;
• (c) zirconia in an amount of from about 10% to about 75%;
• and
• (d) from 0% to about 8% boron carbide.

A submerged tundish shroud for use in continuous casting of molten steel comprising:

• a body portion of a refractory material having a central axial bore for conveyance of molten steel therethrough from an inlet end to an outlet end of said body;
• a seating area portion surrounding said bore at the inlet end thereof;
• a lining portion surrounding said central bore adapted to be in contact with said molten steel and a slagline sleeve portion formed around an exterior circumferential surface of the body adapted to contact a layer of slag in a continuous casting mold, at least one of said seating area portion, lining portion and slagline sleeve portion being made from a carbon bonded refractory composition consisting essentially of, by weight:
• (a) carbon, from about 4% to about 50%;
• (b) zirconium di-boride in an amount of from about 10% to about 90%;
• and
• (c) zirconia in an amount of from about 10% to about 80%.

A tundish shroud wherein at least one of a seating area and slagline sleeve portion is made from a carbon bonded refractory composition consisting essentially of:

• (a) carbon from about 15% to about 25%;
• (b) zirconium di-boride from about 30% to about 40%;
• (c) zirconia from about 30% to about 40%;
• and further including
• (d) boron carbide from about 1% to about 5%.