Patent Publication Number: US-8110142-B2

Title: High yield ladle bottoms

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to refractory linings for metallurgical vessels, and more particularly to a lining bottom for such vessels. The invention is particularly applicable for use in ladles used in handling molten steel, and will be described with particular reference thereto. It will, of course, be appreciated that the present invention has application in other types of metallurgical vessels for handling molten metal. 
     BACKGROUND OF THE INVENTION 
     In the manufacture of steel, molten steel is poured from a metallurgical furnace into a ladle. In pouring the liquid metal from the metallurgical furnace, there is typically some carryover of slag from the furnace into the ladle. The molten steel may also undergo further refinement in the ladle. In this respect, various slag-forming constituents may be added to the liquid steel in the ladle to aid in the refinement process. Thus, the ladle will typically contain molten steel with a layer of slag floating on top of the steel. 
     The molten steel typically is cast, i.e., drained, from the ladle through a well block in a bottom of the ladle. A slide gate or stopper rod serves to open a channel through which the liquid metal exits the ladle. During the casting process, slag particles can become entrained in the stream of liquid steel exiting the ladle. Entrainment can be caused by vortexing, i.e., swirling, in the vicinity of the well block. Vortexing may occur once the level of the liquid metal in the ladle drops to a critical level. The level of steel in the ladle will eventually drop to a point where slag may also be pulled directly into the stream of liquid steel exiting the ladle, even in the absence of vortexing. The slag particles cause contamination of the liquid metal thereby causing the resulting steel to be of lower quality. 
     To avoid contamination of the steel by slag, casting is generally terminated before the level of liquid metal in the ladle reaches the critical level at which slag may be entrained. This results in a certain amount of liquid metal being left in the ladle. This residual liquid metal represents lost production, and is referred to as a “decrease in yield.” To increase yield, steelmakers endeavor to allow the level of the liquid steel in the ladle to fall to as low a level as possible before stopping the casting operation. 
     The present invention provides a ladle bottom that increases the yield of slag-free steel from a steel-making ladle and reduces the entrainment of slag into the stream of liquid metal. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, there is provided a refractory bottom for a metallurgical vessel comprised of a bottom lining having a bottom surface that is dimensioned to overlay a bottom of a metallurgical vessel and an upper surface. The upper surface is comprised of a plurality of discrete sections that include an uppermost section, an intermediate section and a lowermost section. Each section has an upper surface at a discrete elevation such that the upper surface of the uppermost section has a highest elevation and the upper surface of the lowermost section has a lowest elevation. The upper surface of the uppermost section, the intermediate section and the lowermost section comprise a series of successive stepped sections that define a stepped path from the uppermost section downward to the lowermost section. Each successive section of the upper surface is lower than a preceding section. An opening extends through the lowermost section of the bottom lining to allow a molten metal to drain from the vessel. 
     In accordance with another aspect of the present invention, there is provided a refractory bottom for a metallurgical vessel comprised of a bottom lining. The bottom lining has an upper surface comprised of an uppermost section, an intermediate section and a lowermost section. The sections define a path from the uppermost section to the lowermost section. The path is comprised of successive stepped sections. Each section defines a step in the path and each successive step is lower than a preceding step. An opening extends through the lowermost section of the bottom lining to allow molten metal to drain from a metallurgical vessel. 
     An advantage of the present invention is the provision of a refractory bottom lining for a ladle used in a steel making process 
     Another advantage of the present invention is the provision of a refractory bottom lining, as described above that aids in the flow of molten metal in the ladle as the molten metal is drained from the ladle. 
     Another advantage of the present invention is the provision of a bottom lining, as described above that is designed to minimize the amount of slag entrained in the molten metal as the molten metal is drained from the ladle. 
     A still further advantage of the present invention is the provision of a bottom lining, as described above that captures slag on sections of the bottom lining as the molten metal is drained from the ladle. 
     Still another advantage of the present invention is the provision of a bottom lining, as described above that reduces the volume of molten metal remaining in the ladle when the flow of molten metal from the ladle ceases. 
     Still another advantage of the present invention is the provision of a bottom lining, as described above that increases a yield of molten metal by allowing more slag-free, molten metal to be drained from the ladle. 
     These and other advantages will become apparent from the following description of a preferred embodiment taken together with the accompanying drawings and the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention may take physical form in certain parts and arrangement of parts, a preferred embodiment of which will be described in detail in the specification and illustrated in the accompanying drawings which form a part hereof, and wherein: 
         FIG. 1  is a side, sectional view of a ladle for handling molten metal, showing a bottom lining of the ladle according to a first embodiment of the present invention; 
         FIG. 2  is a sectional view taken along lines  2 - 2  of  FIG. 1 ; 
         FIG. 3  is a perspective view of a bottom lining as shown in  FIGS. 1 and 2 ; 
         FIG. 4  is a sectional view taken along lines  4 - 4  of  FIG. 3 , showing a cross-section of the bottom lining; 
         FIG. 5  is a perspective view of a bottom lining, illustrating a second embodiment of the present invention; 
         FIG. 6  is a perspective view of a bottom lining, illustrating a third embodiment of the present invention; 
         FIG. 7  is a sectional view taken along lines  7 - 7  of  FIG. 6 , showing a cross-section of the bottom lining; 
         FIG. 8  is a perspective view of a bottom lining, illustrating a fourth embodiment of the present invention; 
         FIG. 9  is a sectional view taken along lines  9 - 9  of  FIG. 8 , showing a cross-section of the bottom lining; 
         FIG. 10  is a perspective view of a bottom lining, illustrating a fifth embodiment of the present invention; and 
         FIG. 11  is a sectional view taken along lines  11 - 11  of  FIG. 10 , showing a cross-section of the bottom lining. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings wherein the showings are for the purposes of illustrating preferred embodiments of the invention only and not for the purposes of limiting the same, the present invention relates generally to a refractory lining for a metallurgical vessel. The invention is particularly applicable to a steel ladle used in handling molten steel, and will be described in particular reference thereto. It will be appreciated from a further reading of the specification, that the invention is not limited to a steel ladle, but may find advantageous application for linings used in other types of metallurgical vessels handling molten metal. 
       FIG. 1  shows a conventional steel ladle  10  generally comprised of an outer metallic shell  12 . Shell  12  has a cup-shaped bottom  14  and a slightly conical side wall  16 . A refractory lining  22 , comprised of two layers of refractory brick  24 , is disposed along the inner surface of side wall  16 . In the embodiment shown, refractory lining  22  of refractory bricks  24  extends along the entire length of side of wall  16  from bottom  14  to the open upper end of ladle  10 , as best seen in  FIG. 1 . 
     A bottom lining  30  (best seen in  FIG. 3 ) is dimensioned to be disposed on bottom  14  of metallic shell  12 . Bottom lining  30  is basically comprised of a refractory material. In this respect, bottom lining  30  may be comprised of a refractory castable, refractory bricks or a combination of a refractory castable and refractory bricks. 
     Bottom lining  30  is dimensioned to cover and rest upon bottom  14  of shell  12 . In the embodiment shown, bottom lining  30  is essentially oblong in shape, and is dimensioned to have a lower surface  38 . Lower surface  38  is dimensioned to match oblong bottom  14  of shell  12 . A V-shaped slot  34 , best seen in  FIG. 3 , is formed in the peripheral edge of bottom lining  30  to secure bottom lining  30  in ladle  10 , as shall be described in greater detail below. 
     Referring now to  FIGS. 1-3 , bottom lining  30 , illustrating a first embodiment of the present invention, is shown. Bottom lining  30  has an upper portion comprised of discrete sections. In the embodiment shown, the upper portion of bottom lining  30  is comprised of an uppermost section  42 , six (6) intermediate sections  44 ,  46 ,  48 ,  52 ,  54 ,  56  and a lowermost section  58 . Uppermost section  42 , intermediate sections  44 ,  46 ,  48 ,  52 ,  54 ,  56  and lowermost section  58  are each basically pie-shaped. Uppermost section  42 , intermediate sections  44 ,  46 ,  48 ,  52 ,  54 ,  56  and lowermost section  58  are arranged such that each section extends from a center point “A,” best seen in  FIG. 2 . An opening  59  extends through the portion of bottom lining  30  defining lowermost section  58 . Uppermost section  42  has an upper surface  42   a , intermediate section  44  has an upper surface  44   a , intermediate section  46  has an upper surface  46   a , and so forth. Surfaces  42   a ,  44   a ,  46   a ,  48   a ,  52   a ,  54   a ,  56   a ,  58   a  are each disposed at a discrete elevation and combine to form an upper surface  36  of bottom lining  30 . In the embodiment shown, surfaces  42   a ,  44   a ,  46   a ,  48   a ,  52   a ,  54   a ,  56   a ,  58   a  are each parallel and horizontal when ladle  10  is in a normal operating orientation. Surface  42   a  has an elevation higher than an elevation of surfaces  44   a ,  46   a ,  48   a ,  52   a ,  54   a ,  56   a ,  58   a . Surfaces  44   a ,  46   a ,  48   a ,  52   a ,  54   a ,  56   a  are each dimensioned to have a different elevation such that surface  44   a  is higher than surface  46   a , surface  46   a  is higher than surface  48   a , and so forth until surface  56   a , that has an elevation less than surfaces  44   a ,  46   a ,  48   a ,  52   a ,  54   a . Surface  58   a  has an elevation lower than surface  56   a . Surfaces  42   a ,  44   a ,  46   a ,  48   a ,  52   a ,  54   a ,  56   a ,  58   a  are arranged to form a series of successive steps, wherein each surface steps downwardly from surface  42   a , to surfaces  44   a ,  46   a ,  48   a ,  52   a ,  54   a ,  56   a  to surface  58   a.    
     In the embodiment shown, bottom lining  30  is formed by molding sections  42 ,  44 ,  46 ,  48 ,  52 ,  54 ,  56 ,  58  using a single mold (not shown) or using conventionally known forms (not shown). For the method wherein bottom lining  30  is formed in a single mold, a bottom of the mold is dimensioned to match upper surface  36 . In this respect, when a refractory material is poured into the mold, upper surface  36  of bottom lining  30  is formed in the bottom of the mold. Bottom lining  30  is then removed from the mold and inverted such that upper surface  36  of bottom lining  30  faces upward. For the method of forming bottom lining  30  using conventional forms, lowermost section  58  is formed first. Conventionally known forms are then used to aid in forming the remaining sections  42 ,  44 ,  46 ,  48 ,  52 ,  54 ,  56  of bottom lining  30  starting with intermediate section  56 , then intermediate section  54  and so forth. 
     Refractory material, used to form bottom lining  30 , is selected based upon the desired operating characteristics and performance parameters of bottom lining  30 . Various high-temperature refractory castables may find advantageous application in the present invention. In the embodiment of the present invention wherein bottom lining  30  is a monolithic, refractory slab, a low-moisture, high alumina castable, manufactured and sold by North American Refractories Co. under the trade designations D-CAST 85 GOLD or HP-CAST ULTRA is used. Castables having 80% alumina content or higher are preferred. In an embodiment wherein bottom lining  30  is comprised of refractory bricks, an alumina-magnesia-carbon brick, manufactured and sold by North American Refractories Co, under the trade designations COMANCHE FA or COMANCHE FA MX may be used. 
     Spaced-apart lifting pin assemblies  74  are embedded within bottom lining  30 , as best seen in  FIG. 4 , when bottom lining  30  is formed. Each lifting pin assembly  74  is basically comprised of a threaded rod  76  that is threaded into a matching nut  78  that in turn is welded to a flat metallic washer  82 . Several lifting pin assemblies  74  are set into bottom lining  30  at spaced-apart locations when bottom lining  30  is formed. Pin assemblies  74  facilitate movement of bottom lining  30  from its point of fabrication to its ultimate location within ladle  10 . 
     U.S. Pat. No. 6,673,306 entitled “Refractory Lining For Metallurgical Vessel” and U.S. Pat. No. 6,787,098 entitled “Refractory Lining For Metallurgical Vessel,” which are expressly incorporated herein by reference, describe bottom linings for ladles that are pre-formed. 
     As best seen in  FIG. 1 , refractory well block  66  is dimensioned to be disposed in opening  59  of bottom lining  30 . An upper nozzle  68  that is part of a slide gate assembly  72 , shown in phantom, is inserted into well block  66 . 
     The present invention shall now be described with respect to assembling bottom lining  30  into ladle  10 . Bottom lining  30  may be fabricated, as described above, at a location remote from a place where ladle  10  is used to cast molten steel. It is also contemplated that bottom lining  30  may be fabricated at a mill. Whether bottom lining  30  is formed at a remote location or at a mill, bottom lining  30  is then placed within bottom  14  of ladle  10  using spaced-apart lifting assemblies  74 . As shown in  FIGS. 1 and 2 , bottom lining  30  is dimensioned to form a slight gap  62  between refractory lining  22  of ladle  10  and the peripheral edge of bottom lining  30 , as best seen in  FIG. 1 . Well block  66  is positioned within bottom lining  30  after bottom lining  30  is placed in ladle  10 . Well block  66  is located in opening  59  below surface  58   a  of lowermost section  58  such that a recess  61  is formed in bottom lining  30 . Gap  62  is filled with a conventionally known, refractory castable or ramming material  64  to complete the refractory lining covering bottom  14  of ladle  10 . In this respect, castable or ramming material  64  also fills V-shaped slot  34  to aid in securing bottom lining  30  in ladle  10 . 
     The present invention shall now be described with respect to a steel casting operation using ladle  10 . Referring now to  FIGS. 1-4 , a ladle  10  having a bottom lining  30  illustrating a first embodiment of the present invention is shown. As described above, there is typically a carryover of slag from a metallurgical furnace into ladle  10 . The slag typically forms a slag layer that floats on top of the molten metal in ladle  10 . The molten metal in ladle  10  is cast from ladle  10  through well block  66  when slide gate assembly  72  is opened. As the molten metal in ladle  10  drains from ladle  10 , the level of the molten metal decreases. As the level of the molten metal decreases, a point is reached wherein the level of the molten metal in ladle  10  is equal to the level of surface  42   a  of uppermost section  42 . At this point, the slag layer floating on the molten metal engages surface  42   a  of uppermost section  42 . As the level of the molten metal continues to decrease, the slag above surface  42   a  of uppermost section  42  has a tendency to adhere to surface  42   a  of uppermost section  42 . In other words, a portion of the slag floating on the molten metal is retained on surface  42   a  of uppermost section  42  as the molten metal continues to drain from ladle  10 . 
     As the level of the molten metal continues to decrease, a point is reached wherein the level of the molten metal in the ladle is equal to the elevation of surface  44   a  of intermediate section  44 . As the level of the molten metal continues to decrease, the slag above surface  44   a  of intermediate section  44  begins to adhere, i.e., is retained, on surface  44   a  of intermediate section  44 . In this respect, as molten metal continues to drain out of ladle  10 , slag has a tendency to adhere and be retained on surfaces  46   a ,  48   a ,  52   a ,  54   a ,  56   a ,  58   a  in a similar manner as described above for surface  42   a  of uppermost section  42 . In other words, as the molten metal is drained from ladle  10 , the level of the molten metal in ladle  10  decreases such that slag is first retained on surface  42   a  of uppermost section  42 , then slag is retained on surface  44   a  of intermediate section  44 , then slag is retained on surface  46   a  of intermediate section  46 , and so forth until slag is retained on surface  58   a  of lowermost section  58 . Bottom lining  30  is designed such that as molten metal is drained from ladle  10 , slag adheres to and is retained on successive stepped surfaces, namely surfaces  42   a ,  44   a ,  46   a ,  52   a ,  54   a ,  56   a ,  58   a , as the level of the molten metal in ladle  10  decreases. 
     The casting of the molten metal from ladle  10  is preferably stopped before slag above well block  66  is entrained into the stream of molten metal exiting ladle  10 . In this respect, the casting of molten metal from ladle  10  may be stopped when the level of the molten metal in ladle  10  is between surface  42   a  of uppermost section  42  and surface  58   a  of lowermost section  58 . 
     The present invention therefore provides a stepped bottom lining that collects, i.e., retains, slag on an upper surface of the bottom lining, thereby reducing the amount of slag that may exit the ladle when the molten metal is drained from the ladle. The present invention also provides a stepped bottom lining that can improve yield by reducing the amount of residual molten metal remaining in a ladle at the end of a casting process. 
     Referring now to another aspect of the present invention, it is generally known that the draining of molten metal from ladle  10  may also cause a vortex, i.e., a swirling motion, to form in the molten steel above well block  66  once the level of molten metal in ladle  10  reaches a critical level. This vortex can cause the slag floating on the molten metal to be entrained into the molten metal exiting the ladle  10 . In the northern hemisphere, when fluid drains from a tank, a vortex forms within the tank causing the fluid to rotate in a clockwise direction. Bottom lining  30  of the present invention is designed to facilitate flow of the molten metal in ladle  10  in a counter-clockwise direction to retard the formation of the vortex in ladle  10 . In this respect, as molten metal is drained from ladle  10  and the level of the molten metal in ladle  10  decreases, successive sections  42 ,  44 ,  46 ,  48 ,  52 ,  54 ,  56 ,  58  of upper surface  36  are exposed. At one point the level of the molten metal in ladle  10  is between surface  42   a  of uppermost section  42  and surface  44   a  of intermediate section  44 . As the level of the molten metal continues to decrease, molten metal above surface  44   a  of intermediate section  44  flows toward a surface at a lower elevation, i.e., surface  46   a  of intermediate section  46 . In this respect, the molten metal above intermediate section  44  flows in a counter-clockwise direction towards intermediate section  46 . This flow of molten metal, beneath the slag layer, is repeated for each successive section  46 ,  48 ,  52 ,  54 ,  56 . The molten metal flows from successive sections  42 ,  44 ,  46 ,  48 ,  52 ,  54 ,  56  of upper surface  36  along a path “B-B” in a counter-clockwise direction. In this respect, bottom lining  30  is designed so that exposure of successive sections  42 ,  44 ,  46 ,  48 ,  52 ,  54 ,  56 ,  58  of upper surface  36 , creates flow of molten metal in a counter-clockwise direction. It is believed that the flow of molten metal in the counter-clockwise direction, created by exposure of successive stepped sections  42 ,  44 ,  46 ,  48 ,  52 ,  54 ,  56 ,  58 , retards the formation of the vortex in the molten metal in ladle  10  above well block  66 . Retarding the formation of the vortex in the molten metal reduces the likelihood of slag floating on the molten metal being entrained into metal exiting through well block  66 . The present invention, therefore, also provides a stepped bottom lining that retards the formation of a vortex in molten metal in a ladle by creating a flow opposite to the natural flow of the molten metal in the ladle. It is believed that this counter flow reduces the amount of slag that may exit the ladle when the molten metal is drained from ladle. 
     Referring now to  FIG. 5 , a bottom lining  130  illustrating a second embodiment of the present invention is shown. Elements of the second embodiment that are substantially the same as elements of the first embodiment, shown in  FIGS. 1-4 , have been given the same reference numbers and shall not be described in detail. Bottom lining  130  is similar in most respects to bottom lining  30 . In one embodiment, bottom lining  130  is comprised of a castable refractory material. In an alternative embodiment (not shown), bottom lining  130  is comprised of refractory bricks or a combination of a castable refractory material and refractory bricks. Bottom lining  130  has an upper portion comprised of an uppermost section  142 , two (2) intermediate sections  144 ,  146  and a lowermost section  158 . In this respect bottom lining  130  has two (2) intermediate sections  144 ,  146  whereas bottom lining  30  has six (6) intermediate sections  44 ,  46 ,  48 ,  52 ,  54 ,  56 . Uppermost section  142  has an upper surface  142   a , intermediate section  144  has an upper surface  144   a , intermediate section  146  has an upper surface  146   a  and lowermost section  158  has an upper surface  158   a . In the embodiment shown, upper surfaces  142   a ,  144   a ,  146   a ,  158   a  are each parallel and horizontal when ladle  10  is in a normal operating orientation. An upper surface  136  is formed by combining surfaces  142   a ,  144   a ,  146   a ,  158   a.    
     Well block  66  is placed in bottom lining  130  after bottom lining  130  is placed in ladle  10 . Well block  66  is placed in bottom lining  130  below surface  158   a  of lowermost section  158  such that a recess  61  is formed therein, as best seen in  FIG. 5 . 
     The present invention shall now be described with respect to a steel casting operation using bottom lining  130  in ladle  10 . The casting of steel using bottom lining  130  in ladle  10  is similar in most respects to casting steel using bottom lining  30  in ladle  10 . In the second embodiment, the slag adheres to surfaces  142   a ,  144   a ,  146   a ,  158   a  instead of surfaces  42   a ,  44   a ,  46   a ,  48   a ,  52   a ,  54   a ,  56   a ,  58   a , as described above for the first embodiment. In addition, as molten metal drains from ladle  10 , the molten metal above upper surface  136  and beneath the slag layer flows from successive sections  142 ,  144 ,  146 ,  158  of upper surface  136  along a path “D-D” in a counter-clockwise direction. In this respect, bottom lining  130  is designed so that exposure of four (4) successive sections  142 ,  144 ,  146 ,  158  of upper surface  136 , creates flow of molten metal in a counter-clockwise direction. The first embodiment, as described above, includes six (6) successive sections that are exposed to create flow of molten metal in a counter-clockwise direction. 
     Referring now to  FIGS. 6-7 , a bottom lining  230  illustrating a third embodiment of the present invention is shown. As best seen in  FIG. 6 , bottom lining  230  is generally oblong in shape and has an upper portion comprised of discrete sections. In the embodiment shown, the upper portion of bottom lining  230  is comprised of an uppermost section  242 , two (2) intermediate sections  244 ,  246  and a lowermost section  258 . Uppermost section  242 , intermediate sections  244 ,  246  and lowermost section  258  are basically elongated sections that transverse the upper portion of bottom lining  230 . Uppermost section  242  has an upper surface  242   a  and an edge  242   b . Intermediate section  244  has an upper surface  244   a  and an edge  244   b . Intermediate section  246  has an upper surface  246   a  and an edge  246   b . Lowermost section  258  has an upper surface  258   a . In the embodiment shown, edges  242   b ,  244   b ,  246   b  are parallel to each other. Surfaces  242   a ,  244   a ,  246   a ,  258   a  are each disposed at a discrete elevation and combine to form an upper surface  236 . In the embodiment shown, surfaces  242   a ,  244   a ,  246   a ,  258   a  are each parallel and horizontal when ladle  10  is in a normal operating orientation. Surface  242   a  has an elevation higher than an elevation of surfaces  244   a ,  246   a ,  258   a . Surfaces  244   a ,  246   a  are each dimensioned to have a different elevation such that surface  244   a  is higher than surface  246   a . Surface  258   a  has an elevation lower than surface  246   a . Surfaces  242   a ,  244   a ,  246   a ,  258   a  are arranged to form a series of successive steps, wherein each surface steps downwardly from surface  242   a , to surfaces  244   a ,  246   a  to surface  258   a.    
     Well block  66  is positioned within bottom lining  230  after bottom lining  230  is placed in ladle  10 . Well block  66  is placed in bottom lining  230  below surface  258   a  of lowermost section  258  such that a recess  61  is formed therein, as best seen in  FIG. 6 . 
     The present invention shall now be described with respect to a steel casting operation using bottom lining  230  in ladle  10 . As described above, a slag layer typically floats on top of the molten metal in ladle  10 . As the molten metal in ladle  10  is cast from ladle  10 , the level of the molten metal decreases and a portion of the slag floating on the molten metal adheres to and is retained on surface  242   a  of uppermost section  242 . As molten metal continues to drain out of ladle  10 , slag has a tendency to adhere to and be retained on surfaces  246   a ,  248   a ,  258   a . In other words, as the molten metal is drained from ladle  10 , the level of the molten metal in ladle  10  decreases such that slag is first retained on surface  242   a  of uppermost section  242 , then slag is retained on surface  244   a  of intermediate section  244 , then slag is retained on surface  246   a  of intermediate section  246  until slag is retained on surface  258   a  of lowermost section  258 . Bottom lining  230  is designed such that as molten metal is drained from ladle  10 , slag adheres to and is retained on successive stepped sections, namely uppermost section  242 , intermediate sections  244 ,  246  and lowermost section  258 , as the level of the molten metal in ladle  10  decreases. 
     Similar to the first embodiment, as the level of molten metal decreases, the molten metal above upper surface  236  and beneath the slag layer, flows from successive sections  242 ,  244 ,  246 ,  258  of upper surface  236  along a path “E-E.” In this respect, bottom lining  230  is designed so that exposure of successive stepped sections  242 ,  244 ,  246 ,  258  causes molten metal to flow in a direction along the path “E-E.” 
     Referring now to  FIGS. 8-9 , a bottom lining  330  illustrating a fourth embodiment of the present invention is shown. Elements of the forth embodiment that are substantially the same as elements of the third embodiment, shown in  FIGS. 6-7 , have been given the same reference numbers and shall not be described in detail. Bottom lining  330  is similar in most respects to bottom lining  230 . Bottom lining  330  has an upper portion comprised of an uppermost section  242 , two (2) intermediate sections  244 ,  246 , a lowermost section  258  and an impact pad  331 . In this respect bottom lining  330  includes impact pad  331  whereas bottom lining  230  does not include an impact pad. Impact pad  331  has an upper surface  331   a . An upper surface  336  is formed by combining surfaces  242   a ,  244   a ,  246   a ,  258   a ,  331   a.    
     In the embodiment shown, impact pad  331  is a rectangular member typically comprised of a cast, refractory material. In another embodiment (not shown), impact pad  331  is comprised of a plurality of tightly packed high-density and high-temperature refractory bricks or a combination of a cast, refractory material and refractory bricks. In the embodiment shown, impact pad  331  is embedded in bottom lining  330 . 
     The casting of molten metal from ladle  10  containing bottom lining  330  is similar, in most respects, to casting molten metal from ladle  10  containing bottom lining  230 . In the embodiment wherein bottom lining  330  is disposed in ladle  10 , as molten metal is drained from ladle  10 , the level of the molten metal decreases. As the level of the molten metal decreases, a point is reached wherein the level of the molten metal in ladle  10  is equal to the level of surface  331   a  of impact pad  331 . At this point, the slag layer floating on the molten metal engages surface  331   a  of impact pad  331  such that the slag adheres to surface  331   a  of impact pad  331 . As the level of the molten metal continues to decrease, slag adheres to successive sections  242 ,  244 ,  246 ,  258 , as described above for bottom lining  230 . 
     As the level of the molten metal in ladle  10  decreases, molten metal above surface  331   a  of impact pad  331  flows towards surface  242   a  of uppermost section  242  or towards surface  244   a  of intermediate section  244 . As the molten metal continues to drain out of ladle  10 , the molten metal above surface  336  flows to successive stepped sections  246 ,  258 , as described above for bottom lining  230 . The molten metal flows from successive stepped surfaces  331   a ,  242   a ,  244   a ,  246   a ,  258   a  of upper surface  336  along L-shape paths “F-F.” In this respect, bottom lining  330  is designed so that exposure of successive surfaces  331   a ,  242   a ,  246   a ,  258   a , creates flow of molten metal towards well block  66  along paths “F-F.” 
     Referring now to  FIGS. 10-11 , a bottom lining  430  illustrating a fifth embodiment of the present invention is shown. Elements of the fifth embodiment that are substantially the same as elements of the third embodiment shown in  FIGS. 6-7  have been given the same reference numbers and shall not be described in detail. 
     Bottom lining  430  has an upper portion comprised of an uppermost section  442 , an intermediate section  444  and a lowermost section  458 . In this respect, bottom lining  430  has one (1) intermediate section  444  whereas bottom lining  230  has two (2) intermediate sections  244 ,  246 . Uppermost section  442  has an upper surface  442   a , intermediate section  444  has an upper surface  444   a  and lowermost section  458  has an upper surface  458   a . In the embodiment shown, surfaces  442   a ,  444   a ,  458   a  each generally slope downwardly towards well block  66 , as best seen in  FIG. 11 , when ladle  10  is in a normal operating orientation. Surfaces  442   a ,  444   a ,  458   a  combine to form an upper surface  436 . In this respect, bottom lining  430  has stepped surfaces  442   a ,  444   a ,  458   a  that each are sloped whereas bottom lining  230  has stepped surfaces  242   a ,  244   a ,  246   a ,  258   a  that each are horizontal. 
     The operation of casting steel from ladle  10  having bottom lining  430  is similar to casting steel from ladle  10  having bottom lining  230  and shall not be described in detail. Bottom lining  430  is designed to have an upper surface  436  such that the flow of molten metal along path “G-G” (as shown in  FIG. 10 ), is aided by sloping surfaces  442   a ,  444   a ,  458   a  of upper surface  436  toward well block  66 . 
     It should be understood that a bottom lining, according to the present invention, may assume other shapes and configurations without deviating from the present invention. For example, bottom linings,  30 ,  130 ,  230 ,  330 ,  430  each show sections of upper surfaces  36 ,  136 ,  236 ,  336 ,  436  that are generally planar. It is also contemplated that upper surfaces  36 ,  136 ,  236 ,  336 ,  436  may have sections that are non-planar, e.g., convex-shaped or concave-shaped to facilitate a desired flow of metal within ladle  10 . Furthermore, in an alternative embodiment of the present invention all or at least a portion of the refractory cast material of bottom lining  30 ,  130 ,  230 ,  330 ,  430  may be substituted with refractory bricks. It should be further appreciated that each embodiment of the bottom lining described above may be modified to incorporate one or more features of the other embodiments. For example,  FIGS. 1-9  show sections of upper surfaces  36 ,  136 ,  236 ,  336  that are horizontal. It is contemplated that sections of upper surfaces  36 ,  136 ,  236 ,  336  may also be sloped, similar to sections  442 ,  444 ,  458  of upper surface  436 , as shown in  FIGS. 10-11 . 
     Other modifications and alterations will occur to others upon their reading and understanding of the specification. It is intended that all such modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof.