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AssigneeBaker Refractories
InventorsDonald B. Hoover, Franklin A. Renda, Donald J. Griffin, Colin Richmond
Estimating the term…
An improved submerged entry nozzle is provided which is useful in the casting of aluminum killed molten steel. The nozzle has an improved slagline sleeve or collar which surrounds the outer portion of the nozzle to protect it from corrosion during the casting process. The slagline sleeve is made from resin bonded zirconia/graphite which has been formulated so that upon curing of the resin to form resite, there is a reduction in the contractile tendency which results in a reduction in stress fracturing. The reduction of the contractile tendency and the resulting resistance to stress fracturing is achieved by adding an effective amount of calcium oxide to the resin-zirconia-graphite mixture which is used to form the sleeve.
In a composition for forming a slagline sleeve which comprises zirconium oxide, graphite and resin binder capable of forming a resite during a curing reaction which liberates water, said zirconium oxide optionally containing a stabilizing amount of CaO within the crystalline structure thereof
In a method for making a nozzle for pouring molten metal, said nozzle comprising a body portion and a slagline sleeve portion attached thereto;
Dependencies are inferred from the claim text.
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From the US filing history. Foreign family members aren’t listed.
Condensation polymers of aldehydes or ketones: phenol-formaldehyde condensation polymers
Pouring-nozzles: rings, inserts or other means preventing external nozzle erosion by the slag
Manufacturing or repairing thereof: characterised by the materials used therefor
Based on oxide ceramics: containing carbon
Term ended 13 Oct 2019 (estimated)
1. Field of the Invention
The present invention relates to refractory submerged entry nozzles which are used in the continuous casting of aluminum killed molten steel. More particularly this invention pertains to an improved sleeve or collar which surrounds the outer portion of the nozzle to protect it from the corrosive effects of molding powder which floats on the surface of the molten metal contained in the continuous casting mold through which the nozzle is partially immersed. This invention also pertains to the refractory composition which is used to make the improved sleeve or collar.
2. Background Art
FIG. 1 is a cross section of a conventional submerged entry nozzle which shows the location of a slagline sleeve.
FIG. 1 shows the configuration of a conventional submerged nozzle indicated generally by reference numeral 1. The nozzle includes sleeve 2 which is made from zirconia/graphite. A bore 3 extends through the nozzle for the passage of molten steel therethrough. The sleeve 2 is conveniently limited to the slagline portion of the nozzle. However, as noted above, it is not essential to confine the sleeve to the narrow zone around the slagline. In fact, the sleeve may extend along the entire length or any portion thereof so long as it is present in at least a portion of the nozzle which comes in contact with the molten slag of mold powder which floats on the surface of the molten metal in the mold.
The carbon bonded doloma/graphite nozzle for which the sleeve of the present invention is particularly useful is made from a resin bonded blend containing doloma refractory and graphite, particularly flake graphite. The doloma, resin and graphite are mixed and molded into the desired shape of the nozzle, the resin is cured and then the formed nozzle is heated under carbonizing conditions to convert the resin binder into a carbon matrix. Thus, the nozzle contains graphite and doloma within a carbon matrix or network derived from the binder resin by heating the resin under carbonizing conditions.
Calcined sintered dolomite, known as doloma, is a well known commercially available refractory material which is currently used for a variety of refractory applications due to its heat resistant capability. It is made by calcining dolomite (CaCO3.MgCO3) to convert the MgCO3 to MgO and the CaCO3 to CAO. Sintering is then performed on the calcined dolomite to densify the grain.