Refractory element, assembly and tundish for transferring molten metal

Abstract

A refractory element is configured to prevent or limit steel reoxidation in a steel casting process. The refractory element contains a base surrounded by a periphery in a specified geometrical arrangement. The refractory element is constituted of a base surrounded by a periphery in a specified geometrical arrangement.

We claim: 
     
         1 . A refractory element for transferring molten metal comprising:
 a base having a bottom and a main surface,   a main orifice passing through the main surface, and   a periphery surrounding the main surface,   wherein the main orifice has an interior face and a longitudinal axis,   wherein the periphery has an interior face, an exterior face and an upper face,   wherein the upper face of the periphery is higher than the main surface of the refractory element,   wherein the periphery intersects the bottom of the base, and   wherein the exterior face of the periphery forms an angle other than a right angle with the bottom of the base in at least one point in their intersection.   
     
     
         2 . The refractory element of  claim 1 , wherein the exterior face of the periphery forms a right angle with the bottom of the base at two points in their intersection. 
     
     
         3 . The refractory element of  claim 1 , wherein the exterior face of the periphery forms an acute angle with the bottom of the base at all points in their intersection. 
     
     
         4 . The refractory element of  claim 1 , wherein the exterior face of the periphery forms an obtuse angle with the bottom of the base at all points in their intersection. 
     
     
         5 . The refractory element of  claim 1 , wherein the element partially encloses a volume with a cross-section that decreases in size with decreasing distance to the bottom surface. 
     
     
         6 . The refractory element of  claim 1 , wherein the plane of the upper face of the periphery and the plane of the bottom of the base are not parallel. 
     
     
         7 . The refractory element of  claim 1 , wherein the upper face of the periphery comprises an upper level and a lower level joined by two transitional non-vertical, non-horizontal portions. 
     
     
         8 . The refractory element of  claim 1 , wherein the main surface has a geometry selected from the group consisting of circular, oval, truncated circular, truncated oval, and polygonal geometry. 
     
     
         9 . The refractory element of  claim 1 , further comprising a vane extending from the interior face of the periphery. 
     
     
         10 . The refractory element of  claim 1 , further comprising a plurality of vanes extending from the interior face of the periphery. 
     
     
         11 . The refractory element of  claim 1 , further comprising a vane extending from the exterior face of the periphery. 
     
     
         12 . The refractory element of  claim 1 , further comprising a plurality of vanes extending from the exterior face of the periphery. 
     
     
         13 . The refractory element of  claim 1 , further comprising at least one port passing from the exterior face to the interior face of the periphery. 
     
     
         14 . The refractory element of  claim 1 , further comprising a feature located at a position selected from the group consisting of the interior face of the main orifice and the bottom of the base, wherein the feature is selected from the list consisting of a marking, a recess, a protrusion, a groove, a lip, a peg, a bore, a notch, a dimple, a mogul, a ridge, a threaded receiver, a key receiver, a bayonet receiver, a bevel, and a non-circular geometry. 
     
     
         15 . An assembly for the transferring of molten metal comprising
 a refractory element according to  claim 1 , and   a refractory nozzle in communication with the refractory element,   wherein the nozzle has a bore having a longitudinal axis, and   wherein the nozzle has an exterior radial surface configured to mate with the interior face of the main orifice.   
     
     
         16 . The assembly of  claim 15 , wherein the axis of the nozzle bore is aligned with the axis of the main orifice. 
     
     
         17 . The assembly of  claim 15 , wherein the main surface of the base of the element has a lowest level, the lowest level being lower than the top outer edge of the nozzle inlet portion. 
     
     
         18 . The assembly of  claim 15 , wherein the refractory element and the refractory nozzle together comprise a single piece. 
     
     
         19 . The assembly of  claim 15 , wherein the refractory element comprises a main orifice having a non-circular geometry, and wherein the refractory nozzle comprises an exterior radial surface having a non-circular geometry configured to mate with the refractory element. 
     
     
         20 . The assembly of  claim 15 , wherein the refractory element comprises a main orifice interior face having a mating feature, wherein the refractory nozzle comprises an exterior radial surface having a corresponding mating feature configured to engage with the main orifice interior face mating feature. 
     
     
         21 . The assembly of  claim 20 , wherein the mating feature and the corresponding mating feature, when engaged, prevent rotational motion of the element around the longitudinal axis of the bore of the nozzle. 
     
     
         22 . A metallurgical vessel for the casting of molten metal comprising
 an assembly of a refractory nozzle having an inlet portion forming a passage through the bottom wall of the metallurgical vessel and   a refractory element according to  claim 1  surrounding the inlet portion of the nozzle,   wherein the inlet portion of the nozzle has a top outer edge,   wherein the inlet portion of the nozzle has a longitudinal axis,   wherein the main orifice of the element is adapted for matching engagement with at least a portion of the outer surface of the nozzle,   wherein the main surface of the base of the element has a lowest level, the lowest level being lower than the top outer edge of the nozzle inlet portion, and   wherein at least a portion of the periphery of the refractory element is higher than the surface of the bottom wall of the tundish.   
     
     
         23 . The assembly of  claim 15 , wherein the element comprises a gas impervious refractory material. 
     
     
         24 . The assembly of  claim 15 , wherein the nozzle comprises a gas impervious refractory material. 
     
     
         25 . The assembly of  claim 15 , further comprising gas impervious mortar between the nozzle and the refractory element. 
     
     
         26 . The element of  claim 1 , consisting essentially of a high alumina material comprising at least 75 wt. % of Al 2 O 3 , and less than 1.0 wt. % of SiO 2 , less than 5 wt. % of C. 
     
     
         27 . Process for the continuous casting of steel comprising pouring the molten steel from a ladle into a metallurgical vessel according to  claim 22 , and from the metallurgical vessel into a casting mold 
     
     
         28 . The refractory element of  claim 1 , wherein the periphery of the element has a thickness equal to or greater than 2 millimeters, and equal to or less than 100 millimeters.