CA2174266A1 - Tundish impact pad and method - Google Patents
Tundish impact pad and methodInfo
- Publication number
- CA2174266A1 CA2174266A1 CA002174266A CA2174266A CA2174266A1 CA 2174266 A1 CA2174266 A1 CA 2174266A1 CA 002174266 A CA002174266 A CA 002174266A CA 2174266 A CA2174266 A CA 2174266A CA 2174266 A1 CA2174266 A1 CA 2174266A1
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- Canada
- Prior art keywords
- impact
- exit
- area
- direction away
- flow
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
- B22D41/003—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like with impact pads
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Continuous Casting (AREA)
Abstract
An impact pad for reducing the velocity of a liquid steel flow in a tundish includes a base having an impact area upon which liquid steel from a ladle stream impacts and at least one sidewall. The sidewall extends in an upward direction along the periphery of the base and defines a flow area within said impact pad for receiving liquid steel from a ladle stream.
The cross-section of the flow area increases in size in a direction away from the impact area to provide an expanding volume for reducing the velocity of the liquid steel within the impact pad.
The cross-section of the flow area increases in size in a direction away from the impact area to provide an expanding volume for reducing the velocity of the liquid steel within the impact pad.
Description
217~266 -IMPROVED TUNDISH IMPACT PAD AND METHOD
BACKGROUND OF THE INVENTION
This invention is directed to apparatus for reducing surface turbulence in a molten metal bath, and more particularly, to impact pads for reducing surface turbulence generated by an incoming ladle stream in a continuous caster tnn~ h.
Tlln(li.~h~s are located between the ladle delivering liquid steel to the caster and the mold that forms the product. They are large containers for holding a reservoir of liquid steel.
The liquid steel is ~ r~lled from the ladle through a nozzle extending into the t~ln~ h, and the liquid steel is fed at a continuous or semicontinuous flow controlled by a stopper rod, or by a slide gate assembly.
Extensive water flow-model studies have been con(lucted in the past, and continue to be con~ cted today, to develop both methods and appald~us for reducing surface turbulence in the tundish and improving the microcle~nlin~ss of steel products. These watermodelling tests have been beneficial in d~lel "~inil~g critical areas of tundish design such as depth of bath, well block locations, and placement of fluid flow control devices within the tl-n~ h As a result of such studies, it is well-known that the fluid flow generated by the incoming ladle stream is reflected from the flat tundish floor toward the surface of the liquid steel. This generated fluid flow causes a turbulent boiling action and extensive wave motion at the surface of the steel bath. Additionally, where the fluid flow forces are obstructed by structural barriers such as tundish side and end walls, the fluid flow surges upward along such barriers and causes excessive turbulence at the surface of the liquid steel bath. The excessive turbulence produced by the upward surge breaks up the tundish flux cover and produces a dowllw~ld surge around the ladle nozzle. The broken flux cover allows the liquid steel to be exposed to the atmosphere which sets up conditions conducive to altering the chemistry of the steel bath. The chemical changes typically involve loss of alllll-illll,,, from the bath and/or absorption of oxygen and nitrogen into the steel. The dowllwald flow of the liquid steel swirling around the ladle nozzle entrains particles of broken slag cover within the ladle stream.
Modern high quality steel product requirements dictate that hll~ulilies and chemical changes cannot be tolerated. Heretofore, there have been various aLLelll~l~ to reduce or elimin~te surface turbulence within the tundish to improve the quality of the fni.~h~(l steel product. These attempts have included a wide assortment of dams and weirs which redirect the ladle stream fluid flow away from the bath surface. One recent improvement includes the development of an impact pad that elimin~tes surface boil by level~ g the direction of the fluid flow gellel~l~d by the incoming ladle stream. United States Patent No. 5,169,591 granted to Schmidt, et al. on December 8, 1992 discloses such a fluid flow reversing impact pad. The Schmidt impact pad includes at least one sidewall having an undercut portion that extends along the length of the inner surface of the sidewall, the undercut being shaped to receive and reverse the direction of the fluid flow generated by the incoming ladle stream. Schmidt's impact pad elimin~t~s surface boil, and has found widespread use within the industry.
Some impact pad shapes produce high velocity steel flows within the tl-n~ h Highvelocity flow rates can cause "short circuiting," a term used to describe liquid steel moving in a direct flow path from the ladle stream to the discharge nozzle of the t~ln~ h Short circuiting reduces the Illil~i,,,,,,,l residence time of the liquid steel in a tundish and can cause large inclusions to be carried into the caster mold. Instead of using the entire tundish volume for flow, fast moving liquid steel travels along the bottom of the tundish directly to the discharge nozzle, bypassing the majority of the tlm~ h. This creates dead zones within the tl-ntli~h, and reduces inclusion float-out to the slag cover at the bath surface. The dead zone areas freeze up and produce skull. Such conditions reduce the quality and microcle~nlinf~-ss of the finished steel product.
217~266 We have discovered that the above problems can be overcome by casting the refractory material to provide an impact pad shape that reduces the velocity of the steel flowing from the impact pad area.
SUMMARY OF THE INVENTION
It is therefore an object of this invention to improve the microcle~nlintoss of a steel product by reducing the velocity of the liquid steel fluid flow exiting a tundish impact pad.
It is a further object of this invention to improve the microcle~nlin~ss of a steel product by increasing the liquid steel retention time in a tundish to enhance inclusion float out.
And finally, it is a further object of this invention to improve the microcle~nlin~ss of a steel product by preventing short circuiting and eli~ g or reducing the dead zones within a liquid steel bath contained in a tlln~ h.
We have discovered that the foregoing objects can be ~ in~-l with a tundish impact pad comprising a base having an impact area upon which a liquid steel stream from a ladle impacts, and at least one sidewall extending in an upward direction along the periphery of the base, the bounds of the sidewall defining a volumetric area for receiving the liquid steel and having an increasing cross-section in a direction away from the impact area of the base.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 IS a plan view showing the pler~lled embodiment of the impact pad lnvention.
Figure 2 is an elevation view of Figure 1 in cross-section.
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Figure 3 is an isometric view of Figure 1.
Figure 4 is a plan view of an alternate embodiment of the impact pad invention.
Figure 5 is an elevation view of Figure 4 in cross-section.
Figure 6 is an isometric view of Figure 4.
Figure 7 is an isometric view of a still further alternate embodiment of the impact pad invention.
Figure 8 is an elevation view of Figure 7 in cross-section.
Figure 9 is a plan view Figure 7.
Figure 10 is an elevation view in cross-section showing the impact pad of Figure 1 placed in a continuous caster tlln~ h.
Figure 11 is an elevation view in cross-section showing the impact pad of Figure 4 placed in a continuous caster llln-lish.
Figure 12 is an elevation view in cross-section showing the impact pad of Figure 7 placed in a continuous caster tlln~ h Figure 13 is an elevation view in cross-section showing the impact pad of Figure 1 in combination with a flow control dam placed in a continuous caster t ln~ h.
217~266 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The increased demand for cleaner steels has resulted in co"li",li~lg research to advance methods and apparatus for improving the microcle~nlin~.ss of certain steel grades. One such advancement in the art is the discovery of an impact pad for receiving and reversing the fluid flow generated by an incoming ladle stream as taught in the prior U.S. patent 5,169,591. It has now been discovered that the microcle~nlin~-ss of liquid steel can be further improved by reshaping such fluid flow reversing pads to reduce the velocity of the liquid steel flow exiting the impact pad into the main body of a tlmtli~h. It has also been discovered that microcle~nlinl~s~ may be further improved by providing additional flow control devices, such as dams, downstream from the reshaped impact pads. The dowl~lealll flow control devices redirect the liquid steel flow into dead zones within the steel bath. This prevents freeze up and ~lling within the dead zones, and improves the quality of the finished steel product.
Referring to Figures 1 through 3 of the drawings, the impact pad 1 of the plefelled embodiment is a shaped refractory brick or block m~mlf~ red from a castable highalumina refractory material capable of resisting erosion from an incoming ladle stream impacting upon the pad. The impact pad is shaped to dissipate the kinetic energy in a liquid steel flow generated by the incoming ladle stream and reduce its velocity. The refractory impact pad shape includes a base 2, a sidewall 3, a closed end 4, and an open end 5 opposite closed end 4. The open end 5 provides an exit to discharge the liquid steel flow from the impact pad. Sidewall 3 extends in an upward direction along the periphery of base 2 and includes an outside surface 6, an inside surface 7 a top 8 and an undercut 10 that extends along the inside surface 7 of sidewall 3. Top 8 includes a peripheral surface defining an opening 11 through which an incoming ladle stream is directed.
Opening 11 exposes base 2 and provides a large target area for an incoming ladle stream to impact upon the base. Opening 11 extends from a position adjacent the closed end 4 217426~
and commllnicates with open end 5.
The bounds of sidewall 3, and the space between base 2 and undercut 10 define a flow area "A" for receiving the liquid steel flow generated by the incoming ladle stream that impacts upon base 2 of the pad. The inside surface 7 of sidewall 3 and undercut 10 are flared in a bell like shape to create a continuously increasing llal~velse cross-section along the length of the flow area "A" As a result, the transverse cross-section adjacent closed end 4 is smaller than the cross-section at open end 5.
As more clearly shown in Figure 2, the geometry of the base sidewall and top forms the bell like shape or flow area that extends from the ladle stream impact area to the open end 5. The height of sidewall 3 adjacent the closed end 4 is smaller than the height of the sidewall at the open end 5. This dirr~lellce in height along sidewall 3 causes undercut 10 to be inclined in an upward direction away from the closed 4 end toward the open end 5.
The upward pitch of the undercut gives a closed end height "h" that is less than an open end height "H". Additionally, the inside surface 7 of sidewall 3, as well as the legs 12 of opening 11, are angled in an outward direction away from the closed end 4 toward the open end 5. As shown in Figure 1, the angled sidewall surface 7 gives a closed end sidewall width "w" that is less than an open end sidewall width "W", and the angled legs of opening 11 give a closed end opening "o" that is less than the open end opening "O".
It should also be noticed that sidewall 8 may include end portions 9 that have an inside surface that is not parallel to inside surface 7. The end portions 9 are adjacent open end 5, and they are shaped to direct the liquid steel in a flow direction substantially parallel to the tundish sidewalls after the steel is discharged from the impact pad. This prevents the liquid steel from ~m~hing into the refractory lining of the sidewalls, and it reduces erosion and premature wear on the lining.
- 217~6~
As heretofore disclosed, the transverse cross-section along the flow area "A" increases continuously from closed end 4 toward open 5 of the impact pad. This dissipates the kinetic energy as the liquid steel flow moves from the smaller cross-section adjacent closed end 4 toward the largest cross-section at the open end 5. As the energy of the liquid steel flow decreases due to its expanding cross-section, the velocity of the liquid steel flow decreases, and the steel is discharged from open end 5 at a reduced velocity. Additionally, because the undercut 10 is inclined in an upward direction away from closed end 4 toward open end 5, and because end portions 9 are substantially parallel to the tundish sidewalls, the liquid steel flow is forced to move away from the impact pad in an upward direction that is substantially parallel to the tundish sidewalls. This causes the liquid steel to flow toward dead zones normally found at the discharge end of a ~lnfli~h. The slower upward flow pattern avoids short Cif~;ui~ g within the tundish and provides effective retention time to improve inclusion float-out to the slag cover on the surface of the heat. Freeze-up and .skllllin~ within the tundish are also reduced because the improved flow uses a larger portion of the tundish for circ~ ting the steel. As a result, a cleaner steel product is produced.
Referring to Figures 4 through 6 of the drawings, an alternate embodiment of the impact pad invention is shown coll-p-ising an impact pad 20 having a base 21 and a first sidewall 22 parallel to a second sidewall 23. The parallel sidewalls 22 and 23 extend in an upward direction along opposite sides of the base 21, and each sidewall includes an outside surface 24, an inside surface 25, and a top 26. The two top portions 26 extend inward from sidewalls 22 and 23 and provide an undercut 28 along the inside surface 25 of both sidewalls. A longihl(lin~l opening 29 extends between the opposed undercuts 28 to expose the impact area 32 of base 21 and provide a large target for an incoming ladle stream.
Impact pad 20 is flared in a double bell like shape to provide an increasing transverse cross-section in two directions. The first bell like shape includes a flow area "Aa" that extends from the impact area 32 toward a first open end 30, and the second bell like shape includes a flow area "Ab" that extends from the impact area 32 toward a second open end 31 opposite the first open end 30. The size of the transverse cross-section of both flow areas increases in the direction away from the impact area 32 toward both respective open ends 30 and 31. As more clearly shown in Figure 5, sidewalls 22 and 23 increases in height in a direction away from the impact area 32 toward each open end 30 and 31. The difference in sidewall height causes the opposed undercuts 28 to be inclined in an upward direction away from the impact area 32 toward both open ends 30 and 31. This gives an impact area height "h" that is less than both open end heights "H". Additionally, sidewalls 22 and 23, as well as the legs 33 of opening 29, are angled in an ou~w~d direction away from the impact area 32 toward the open ends 30 and 31. As shown in Figure 4, the angled sidewalls give a sidewall width "w" adjacent the impact area that is less than a sidewall width "W" at both open ends 30 and 31, and the angled legs 33 give an opening width "o" adjacent the impact area that is less an opening "O" at both open ends.
The transverse cross-section of both flow areas "Aa" and "Ab" increases continuously from the impact area 32 toward both open ends 30 and 31. The increasing cross-section causes a decrease in the kinetic energy of the liquid steel flow as it moves from the smaller cross-section at the impact area 32, toward the larger cross-sections adjacent both open ends 30 and 31. As the kinetic energy of the liquid steel flow decreases due to its increasing cross-section as it moves along the length of flow areas "Aa" and "Ab", the velocity of the liquid steel flow decreases, and the steel exits both open ends 30 and 31 at a reduced velocity. Additionally, because the undercuts 28 are inclined in an upward direction away from the impact area 32 toward both open ends 30 and 31, and because end portions 27 are substantially parallel to the tundish sidewalls, the liquid steel flow is forced to move away from the impact pad in an upward direction that is substantially parallel to the tundish sidewalls. This causes the liquid steel to flow toward dead zones normally found at the opposite discharge ends of the tlln~ h The slower upward flow patterns avoid short c~l~;uiLillg within the tundish and provides effective retention time to improve inclusion float-out to the slag cover at the surface of the heat. Freeze-up and ~ lling 217g266 -within the tundish are also reduced because the improved flow uses a larger portion of the tundish for circulating the steel. As a result, a cleaner steel product is produced.
Although Figures 4 through 6 show the flow areas "Aa" and "Ab" being the same size and shape, it should be understood that one of the open ends 30 or 31 could be larger than the opposite open end to provide a larger flow area along one half of the impact pad. Such variations in the flow areas enable the impact pad to be designed to meet dirrelellt flow pattern requirements that may exist at opposite ends of a continuous caster t ln~ h.
Referring now to Figure 7 through 9 of the drawings, a still further alternate embodiment of the impact pad invention is shown C~ lisillg an impact pad 40 having a base 41, a top 45, and a sidewall 42 including an outside surface 43 and an inside surface 44. The sidewall extends continuously along the periphery of the base 41 between the base 41 and top 45, and the top extends inward from the sidewall to form an undercut that extends along the inside surface 44 of sidewall 42. The top 45 also includes a peripheral surface that defines an opening 49 through which an incoming ladle stream is directed to impact upon base 41.
Impact pad 40 is also flared in a double bell like shape similar to the embodiment shown in Figures 4-6. However, the continuous sidewall 42 provides no open ends to discharge the liquid steel flow from the impact pad, and the liquid steel is required to exit through opening 49. The closed bell like shape of impact pad 40 includes an impact area 52 for receiving the incoming ladle stream, a first exit end 50, and a second exit end 51 opposite the first exit end 50. The double bell like shape provides two flow areas "Aa" and "Ab"
along the length of the impact pad 40. Similar to the previous embodiments, the flared shape of the flow areas provides an increasing cross-section in a direction away form the impact area 52 toward both exit ends 50 and 51. Flow areas "Aa" and "Ab" are both shaped to receive the liquid steel stream flow generated by the incoming ladle stream imp~rting upon the impact area of base 41 and direct it toward the larger cross-sectional 217426~
areas at both exit ends 50 and 51.
Impact pad 40 is similar to the above embodiments in that sidewall 42 also increases in height in a direction away from the impact area 52 toward both exit ends 50 and 51. The difference in height along sidewall 42 causes undercut 47 to be inclined in an upward direction away from the impact area 52 toward both closed exit ends 50 and 51. This gives an undercut height "h" adjacent the impact area that is less than undercut height "H"
at both exit ends. Additionally, the inside surface 44 of sidewall 42 is angled in an oulwdrd direction away from the impact area 52 toward both exit ends 50 and 51, and the opening 49 is also angled in an ~ulward direction from the impact area 52 toward both exit ends 50 and 51. The angle of the inside wall surface 44 gives a sidewall width "w"
adjacent the impact area that is less than a sidewall width "W" at both exit ends.
Likewise, the angle of opening 49 gives an opening width "o" adjacent the impact area that is less than an opening width "O" at both exit ends 50 and 51.
The increasing size of the transverse cross-section along the length of both flow areas "Aa" and "Ab" dissipates the kinetic energy in the liquid steel flow gelleldl~d by the incoming ladle stream. The kinetic energy is dissipated as the liquid steel flow moves from the smallest flow area cross-section adjacent the impact area 52 toward the largest flow area cross-sections at both exit ends 50 and 51. As the kinetic energy is dissipated the velocity of the liquid steel flow is decreased, and the steel exits the impact pad at or near the opening width "O" of opening 49. The liquid steel flow exits the impact pad through opening 49 in an upward direction at a reduced velocity. The slower upward flow pattern avoids short cir~;uilil1g within the tundish and provides effective retention time to improve inclusion float-out to the slag cover on the surface of the heat. Freeze-up and ~kl-lling within the tundish are also reduced because the improved flow uses a larger portion of the tundish for circulating the steel. As a result, a cleaner steel product is produced.
217g26~
Although Figures 7 through 9 show the flow areas "Aa" and "Ab" being the same size and shape, it should be understood that either one of the exit ends 50 or 51 could be larger than the opposite exit end to provide a larger flow area along one half of the impact pad.
Such variations in the flow area enable the impact pad to be designed to meet dirrelellL
flow pattern requirements at opposite ends of a continuous caster tundish.
Each of the above three impact pad embodiments, shown as impact pads 1, 20 and 40 respectively, have vertical sidewalls extending in an upward direction along the periphery of the impact pad base. For example, in the pler~ d embodiment shown in Figures 1-3, impact pad 1 includes a base 2, a top 8 and a sidewall 3. The sidewall extends along the periphery of base 2 between the base and top surface 8. Sidewall 8 includes a shaped inside surface 7 that receives and reverses the direction of a liquid steel flow gellel~t~d by the incoming ladle stream impacting upon base 2. The plane of inside surface 7 intersects the plane of base 2 and the plane of top 8 at a sharp angle of 90 or less to provide a sharp angled undercut along the inside surface of the sidewall.
It has been discovered that if a flow reversing undercut has a sharp angle where the plane of the sidewall intersects the plane of the top, and where the plane of the sidewall intersects the plane of the base of the impact pad, energy (li~ip~tion is greater because the sharp angles create an abrupt direction change that increases friction between the shaped refractory and particles of liquid steel. The increased energy (li~ip~tion gellel~t~d by the sharp angled undercut expends more kinetic energy than the stre~mlin~ undercuts that were taught in the past. As a result the liquid steel flow is discharged from the impact pad at a lower velocity than achieved by using past impact pad designs.
Referring now to Figure 10 of the drawings, impact pad 1 is shown placed within a tundish 60 having a first end wall 61 opposite a second end wall 62. The impact pad is located at the tundish end opposite the discharge well block 63, and the pad is positioned to receive an incoming ladle stream 64 from a nozzle or ladle shroud 65.
217~26~
-The incoming ladle stream impacts upon the base 2 and radiates in an oulwald liquid steel flow "F" toward the sidewall 3. Undercut 10 reverses the r~ ting liquid steel flow back into the incoming ladle stream, and friction between the undercut and liquid steel flow as well as friction generated by collisions between the reversed liquid steel flow and the S incoming ladle stream, dissipates the kinetic energy in the liquid steel. The flowing liquid steel is contained within the flow area "A" and it moves in a direction away from the ladle stream impact area toward open end 5. As the liquid steel flow moves along the flow area toward the open end, its cross-section is increased because of the increasing shape of the flow area "A". The increasing cross-section of the liquid steel flow dissipates additional kinetic energy in the steel and further reduces the velocity of the liquid steel being discharged from the impact pad. The steel exits opening 5 at a greater reduced velocity than would be achieved by using only the reversing undercut shape of the impact pad.
Additionally, because the top of the impact pad inclined in an upward direction away from closed end 4 toward open end 5, and because end portions 9 are substantially parallel to the tundish sidewalls 66, the liquid steel flow is forced to move through the steel bath 67 in an upward direction that is substantially parallel to the tundish sidewalls. This causes the liquid steel to flow toward dead zones normally found at the discharge end 62 of a tlln(li~h. This slower upward flow pattern avoids short circuiting within the tundish and provides effective retention time to improve inclusion float-out to the slag cover 68 at the surface of the heat. Freeze-up and ~ lling within the tundish are also reduced because the improved flow uses a larger portion of the tundish for circ~ ting the steel. As a result, a cleaner steel product is produced.
Figure 11 shows impact pad 20 placed within a tundish 70 having at least two discharge nozzles 71. Tundish 70 includes a first end wall 72 opposite a second end wall 73. The impact pad is positioned between the discharge nozzles to receive an incoming ladle stream 74 from a nozzle or ladle shroud 75.
217~26S
The incoming ladle stream impacts upon the base 21 of the pad and ge~ dles a liquid steel flow "F" that radiates ~uLwdld toward the undercut 28 extending along the inside surface of sidewalls 22 and 23. The liquid steel flow is reversed back into the incoming ladle stream by the undercut portion 28. As heretofore disclosed, the r~velsillg feature of undercut 28 dissipates kinetic energy in the liquid steel flow, and the liquid steel flow is contained within the flow areas "Aa" and "Ab" of the impact pad. The liquid steel flow moves in a direction away from the ladle stream impact area toward both open ends 30 and 31. The increasing transverse cross-section along the lengths of the flow areas "Aa" and "Ab" further dissipates kinetic energy within the liquid steel flow, and the steel exits the pad through the open ends 30 and 31 at a greater reduced velocity as explained in the plcl~ d embodiment.
The exiting liquid steel flow "F" enters the main body of the tundish in a direction controlled by incline of undercut 28 and the angle of the inside surface 25. Additionally, because the undercut 28 is inclined in an upward direction, and because end portions 27 are substantially parallel to the tundish sidewalls 78, the liquid steel flow is forced to move through the steel bath 77 in an upward direction that is substantially parallel to the tundish sidewalls. This causes the liquid steel to flow toward dead zones normally found at both discharge ends 72 and 73 of the tlln(li~h. This slower upward flow pattern avoids short circuiting within the tundish and provides effective retention time to improve inclusion float-out to the slag cover 76 on the surface of the heat. Freeze-up and ~-llin~ within the tundish are also reduced because the improved flow uses a larger portion of the tundish for circul~ting the steel. As a result, a cleaner steel product is produced.
Figure 12 shows impact pad 40 placed within a tundish 80 having at least two discharge nozzles 81. Tundish 80 includes a first end wall 82 opposite a second end wall 83. The impact pad is positioned between the discharge nozzles to receive an incoming ladle stream 84 from a nozzle or ladle shroud 85.
The incoming ladle stream impacts upon the base 41 of the pad and radiates ~ulward in a liquid steel flow "F" toward the inside surface 44 of sidewall 42. The liquid steel flow is reversed back into the incoming ladle stream by the undercut portion 47, and as described above, friction between the undercut and liquid steel flow as well as friction generated by collisions between the reversed liquid steel flow and incoming ladle stream, dissipate the kinetic energy in the liquid steel.
As illustrated in the drawing, the flow areas "Aa" and "Ab" contain the liquid steel flow within the impact pad, and the liquid steel flow moves in a direction away from the ladle stream impact area 52 toward the exit closed ends 50 and 51. As the steel flow moves toward the exit ends its cross-section is increased and kinetic energy is further dissipated.
The decrease in kinetic energy causes the velocity of the liquid steel flow to decrease as it moves away from the impact area toward both exit ends, and the liquid steel flow is discharged from the impact pad through opening 49 at opening width "O" located adjacent both exit ends 50 and 51.
The exiting liquid steel flow "F" enters the main body of the tundish in an upward direction at a more reduced velocity than would be achieved by using only the flow reversing undercut feature without the increasing flow areas "Aa" and "Ab". Because the flow moves in a slowed upward direction, the liquid steel moves through the steel bath 87 toward dead zones normally found at both discharge ends 82 and 83 of a tlmtli~h. This slower upward flow pattern avoids short circuiting within the tundish and provides effective retention time to improve inclusion float-out to the slag cover 86 on the surface of the heat. Freeze-up and ~lllin~ within the tundish are also reduced because the improved flow uses a larger portion of the tundish for circul~ting the steel. As a result, a cleaner steel product is produced.
Figure 13 shows the plefell~d embodiment of the impact pad used in combination with at least one additional flow control device 90 placed downstream from the impact pad. The 217426~
slower velocity of the liquid steel flow "F" exiting the open end of the impact pad allows for better flow control of the liquid steel dowl~Llealll of the impact pad. Dam 90 redirects the slower steel upward flow below the slag cover 91 without breaking up the slag cover.
Such a flow path enhances inclusion float-out and produces a cleaner steel product.
While this invention has been described as having a pl~r~lled design, it is understood that it is capable of further modifications, uses, and/or adaptations following in general the principle of the invention and including such depalLules from the present disclosure as come within known or customary practice in the art to which the invention pertains, and 10 as may be applied to the essential features set forth herein, and fall within the scope of the invention limited by the appended claims.
BACKGROUND OF THE INVENTION
This invention is directed to apparatus for reducing surface turbulence in a molten metal bath, and more particularly, to impact pads for reducing surface turbulence generated by an incoming ladle stream in a continuous caster tnn~ h.
Tlln(li.~h~s are located between the ladle delivering liquid steel to the caster and the mold that forms the product. They are large containers for holding a reservoir of liquid steel.
The liquid steel is ~ r~lled from the ladle through a nozzle extending into the t~ln~ h, and the liquid steel is fed at a continuous or semicontinuous flow controlled by a stopper rod, or by a slide gate assembly.
Extensive water flow-model studies have been con(lucted in the past, and continue to be con~ cted today, to develop both methods and appald~us for reducing surface turbulence in the tundish and improving the microcle~nlin~ss of steel products. These watermodelling tests have been beneficial in d~lel "~inil~g critical areas of tundish design such as depth of bath, well block locations, and placement of fluid flow control devices within the tl-n~ h As a result of such studies, it is well-known that the fluid flow generated by the incoming ladle stream is reflected from the flat tundish floor toward the surface of the liquid steel. This generated fluid flow causes a turbulent boiling action and extensive wave motion at the surface of the steel bath. Additionally, where the fluid flow forces are obstructed by structural barriers such as tundish side and end walls, the fluid flow surges upward along such barriers and causes excessive turbulence at the surface of the liquid steel bath. The excessive turbulence produced by the upward surge breaks up the tundish flux cover and produces a dowllw~ld surge around the ladle nozzle. The broken flux cover allows the liquid steel to be exposed to the atmosphere which sets up conditions conducive to altering the chemistry of the steel bath. The chemical changes typically involve loss of alllll-illll,,, from the bath and/or absorption of oxygen and nitrogen into the steel. The dowllwald flow of the liquid steel swirling around the ladle nozzle entrains particles of broken slag cover within the ladle stream.
Modern high quality steel product requirements dictate that hll~ulilies and chemical changes cannot be tolerated. Heretofore, there have been various aLLelll~l~ to reduce or elimin~te surface turbulence within the tundish to improve the quality of the fni.~h~(l steel product. These attempts have included a wide assortment of dams and weirs which redirect the ladle stream fluid flow away from the bath surface. One recent improvement includes the development of an impact pad that elimin~tes surface boil by level~ g the direction of the fluid flow gellel~l~d by the incoming ladle stream. United States Patent No. 5,169,591 granted to Schmidt, et al. on December 8, 1992 discloses such a fluid flow reversing impact pad. The Schmidt impact pad includes at least one sidewall having an undercut portion that extends along the length of the inner surface of the sidewall, the undercut being shaped to receive and reverse the direction of the fluid flow generated by the incoming ladle stream. Schmidt's impact pad elimin~t~s surface boil, and has found widespread use within the industry.
Some impact pad shapes produce high velocity steel flows within the tl-n~ h Highvelocity flow rates can cause "short circuiting," a term used to describe liquid steel moving in a direct flow path from the ladle stream to the discharge nozzle of the t~ln~ h Short circuiting reduces the Illil~i,,,,,,,l residence time of the liquid steel in a tundish and can cause large inclusions to be carried into the caster mold. Instead of using the entire tundish volume for flow, fast moving liquid steel travels along the bottom of the tundish directly to the discharge nozzle, bypassing the majority of the tlm~ h. This creates dead zones within the tl-ntli~h, and reduces inclusion float-out to the slag cover at the bath surface. The dead zone areas freeze up and produce skull. Such conditions reduce the quality and microcle~nlinf~-ss of the finished steel product.
217~266 We have discovered that the above problems can be overcome by casting the refractory material to provide an impact pad shape that reduces the velocity of the steel flowing from the impact pad area.
SUMMARY OF THE INVENTION
It is therefore an object of this invention to improve the microcle~nlintoss of a steel product by reducing the velocity of the liquid steel fluid flow exiting a tundish impact pad.
It is a further object of this invention to improve the microcle~nlin~ss of a steel product by increasing the liquid steel retention time in a tundish to enhance inclusion float out.
And finally, it is a further object of this invention to improve the microcle~nlin~ss of a steel product by preventing short circuiting and eli~ g or reducing the dead zones within a liquid steel bath contained in a tlln~ h.
We have discovered that the foregoing objects can be ~ in~-l with a tundish impact pad comprising a base having an impact area upon which a liquid steel stream from a ladle impacts, and at least one sidewall extending in an upward direction along the periphery of the base, the bounds of the sidewall defining a volumetric area for receiving the liquid steel and having an increasing cross-section in a direction away from the impact area of the base.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 IS a plan view showing the pler~lled embodiment of the impact pad lnvention.
Figure 2 is an elevation view of Figure 1 in cross-section.
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Figure 3 is an isometric view of Figure 1.
Figure 4 is a plan view of an alternate embodiment of the impact pad invention.
Figure 5 is an elevation view of Figure 4 in cross-section.
Figure 6 is an isometric view of Figure 4.
Figure 7 is an isometric view of a still further alternate embodiment of the impact pad invention.
Figure 8 is an elevation view of Figure 7 in cross-section.
Figure 9 is a plan view Figure 7.
Figure 10 is an elevation view in cross-section showing the impact pad of Figure 1 placed in a continuous caster tlln~ h.
Figure 11 is an elevation view in cross-section showing the impact pad of Figure 4 placed in a continuous caster llln-lish.
Figure 12 is an elevation view in cross-section showing the impact pad of Figure 7 placed in a continuous caster tlln~ h Figure 13 is an elevation view in cross-section showing the impact pad of Figure 1 in combination with a flow control dam placed in a continuous caster t ln~ h.
217~266 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The increased demand for cleaner steels has resulted in co"li",li~lg research to advance methods and apparatus for improving the microcle~nlin~.ss of certain steel grades. One such advancement in the art is the discovery of an impact pad for receiving and reversing the fluid flow generated by an incoming ladle stream as taught in the prior U.S. patent 5,169,591. It has now been discovered that the microcle~nlin~-ss of liquid steel can be further improved by reshaping such fluid flow reversing pads to reduce the velocity of the liquid steel flow exiting the impact pad into the main body of a tlmtli~h. It has also been discovered that microcle~nlinl~s~ may be further improved by providing additional flow control devices, such as dams, downstream from the reshaped impact pads. The dowl~lealll flow control devices redirect the liquid steel flow into dead zones within the steel bath. This prevents freeze up and ~lling within the dead zones, and improves the quality of the finished steel product.
Referring to Figures 1 through 3 of the drawings, the impact pad 1 of the plefelled embodiment is a shaped refractory brick or block m~mlf~ red from a castable highalumina refractory material capable of resisting erosion from an incoming ladle stream impacting upon the pad. The impact pad is shaped to dissipate the kinetic energy in a liquid steel flow generated by the incoming ladle stream and reduce its velocity. The refractory impact pad shape includes a base 2, a sidewall 3, a closed end 4, and an open end 5 opposite closed end 4. The open end 5 provides an exit to discharge the liquid steel flow from the impact pad. Sidewall 3 extends in an upward direction along the periphery of base 2 and includes an outside surface 6, an inside surface 7 a top 8 and an undercut 10 that extends along the inside surface 7 of sidewall 3. Top 8 includes a peripheral surface defining an opening 11 through which an incoming ladle stream is directed.
Opening 11 exposes base 2 and provides a large target area for an incoming ladle stream to impact upon the base. Opening 11 extends from a position adjacent the closed end 4 217426~
and commllnicates with open end 5.
The bounds of sidewall 3, and the space between base 2 and undercut 10 define a flow area "A" for receiving the liquid steel flow generated by the incoming ladle stream that impacts upon base 2 of the pad. The inside surface 7 of sidewall 3 and undercut 10 are flared in a bell like shape to create a continuously increasing llal~velse cross-section along the length of the flow area "A" As a result, the transverse cross-section adjacent closed end 4 is smaller than the cross-section at open end 5.
As more clearly shown in Figure 2, the geometry of the base sidewall and top forms the bell like shape or flow area that extends from the ladle stream impact area to the open end 5. The height of sidewall 3 adjacent the closed end 4 is smaller than the height of the sidewall at the open end 5. This dirr~lellce in height along sidewall 3 causes undercut 10 to be inclined in an upward direction away from the closed 4 end toward the open end 5.
The upward pitch of the undercut gives a closed end height "h" that is less than an open end height "H". Additionally, the inside surface 7 of sidewall 3, as well as the legs 12 of opening 11, are angled in an outward direction away from the closed end 4 toward the open end 5. As shown in Figure 1, the angled sidewall surface 7 gives a closed end sidewall width "w" that is less than an open end sidewall width "W", and the angled legs of opening 11 give a closed end opening "o" that is less than the open end opening "O".
It should also be noticed that sidewall 8 may include end portions 9 that have an inside surface that is not parallel to inside surface 7. The end portions 9 are adjacent open end 5, and they are shaped to direct the liquid steel in a flow direction substantially parallel to the tundish sidewalls after the steel is discharged from the impact pad. This prevents the liquid steel from ~m~hing into the refractory lining of the sidewalls, and it reduces erosion and premature wear on the lining.
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As heretofore disclosed, the transverse cross-section along the flow area "A" increases continuously from closed end 4 toward open 5 of the impact pad. This dissipates the kinetic energy as the liquid steel flow moves from the smaller cross-section adjacent closed end 4 toward the largest cross-section at the open end 5. As the energy of the liquid steel flow decreases due to its expanding cross-section, the velocity of the liquid steel flow decreases, and the steel is discharged from open end 5 at a reduced velocity. Additionally, because the undercut 10 is inclined in an upward direction away from closed end 4 toward open end 5, and because end portions 9 are substantially parallel to the tundish sidewalls, the liquid steel flow is forced to move away from the impact pad in an upward direction that is substantially parallel to the tundish sidewalls. This causes the liquid steel to flow toward dead zones normally found at the discharge end of a ~lnfli~h. The slower upward flow pattern avoids short Cif~;ui~ g within the tundish and provides effective retention time to improve inclusion float-out to the slag cover on the surface of the heat. Freeze-up and .skllllin~ within the tundish are also reduced because the improved flow uses a larger portion of the tundish for circ~ ting the steel. As a result, a cleaner steel product is produced.
Referring to Figures 4 through 6 of the drawings, an alternate embodiment of the impact pad invention is shown coll-p-ising an impact pad 20 having a base 21 and a first sidewall 22 parallel to a second sidewall 23. The parallel sidewalls 22 and 23 extend in an upward direction along opposite sides of the base 21, and each sidewall includes an outside surface 24, an inside surface 25, and a top 26. The two top portions 26 extend inward from sidewalls 22 and 23 and provide an undercut 28 along the inside surface 25 of both sidewalls. A longihl(lin~l opening 29 extends between the opposed undercuts 28 to expose the impact area 32 of base 21 and provide a large target for an incoming ladle stream.
Impact pad 20 is flared in a double bell like shape to provide an increasing transverse cross-section in two directions. The first bell like shape includes a flow area "Aa" that extends from the impact area 32 toward a first open end 30, and the second bell like shape includes a flow area "Ab" that extends from the impact area 32 toward a second open end 31 opposite the first open end 30. The size of the transverse cross-section of both flow areas increases in the direction away from the impact area 32 toward both respective open ends 30 and 31. As more clearly shown in Figure 5, sidewalls 22 and 23 increases in height in a direction away from the impact area 32 toward each open end 30 and 31. The difference in sidewall height causes the opposed undercuts 28 to be inclined in an upward direction away from the impact area 32 toward both open ends 30 and 31. This gives an impact area height "h" that is less than both open end heights "H". Additionally, sidewalls 22 and 23, as well as the legs 33 of opening 29, are angled in an ou~w~d direction away from the impact area 32 toward the open ends 30 and 31. As shown in Figure 4, the angled sidewalls give a sidewall width "w" adjacent the impact area that is less than a sidewall width "W" at both open ends 30 and 31, and the angled legs 33 give an opening width "o" adjacent the impact area that is less an opening "O" at both open ends.
The transverse cross-section of both flow areas "Aa" and "Ab" increases continuously from the impact area 32 toward both open ends 30 and 31. The increasing cross-section causes a decrease in the kinetic energy of the liquid steel flow as it moves from the smaller cross-section at the impact area 32, toward the larger cross-sections adjacent both open ends 30 and 31. As the kinetic energy of the liquid steel flow decreases due to its increasing cross-section as it moves along the length of flow areas "Aa" and "Ab", the velocity of the liquid steel flow decreases, and the steel exits both open ends 30 and 31 at a reduced velocity. Additionally, because the undercuts 28 are inclined in an upward direction away from the impact area 32 toward both open ends 30 and 31, and because end portions 27 are substantially parallel to the tundish sidewalls, the liquid steel flow is forced to move away from the impact pad in an upward direction that is substantially parallel to the tundish sidewalls. This causes the liquid steel to flow toward dead zones normally found at the opposite discharge ends of the tlln~ h The slower upward flow patterns avoid short c~l~;uiLillg within the tundish and provides effective retention time to improve inclusion float-out to the slag cover at the surface of the heat. Freeze-up and ~ lling 217g266 -within the tundish are also reduced because the improved flow uses a larger portion of the tundish for circulating the steel. As a result, a cleaner steel product is produced.
Although Figures 4 through 6 show the flow areas "Aa" and "Ab" being the same size and shape, it should be understood that one of the open ends 30 or 31 could be larger than the opposite open end to provide a larger flow area along one half of the impact pad. Such variations in the flow areas enable the impact pad to be designed to meet dirrelellt flow pattern requirements that may exist at opposite ends of a continuous caster t ln~ h.
Referring now to Figure 7 through 9 of the drawings, a still further alternate embodiment of the impact pad invention is shown C~ lisillg an impact pad 40 having a base 41, a top 45, and a sidewall 42 including an outside surface 43 and an inside surface 44. The sidewall extends continuously along the periphery of the base 41 between the base 41 and top 45, and the top extends inward from the sidewall to form an undercut that extends along the inside surface 44 of sidewall 42. The top 45 also includes a peripheral surface that defines an opening 49 through which an incoming ladle stream is directed to impact upon base 41.
Impact pad 40 is also flared in a double bell like shape similar to the embodiment shown in Figures 4-6. However, the continuous sidewall 42 provides no open ends to discharge the liquid steel flow from the impact pad, and the liquid steel is required to exit through opening 49. The closed bell like shape of impact pad 40 includes an impact area 52 for receiving the incoming ladle stream, a first exit end 50, and a second exit end 51 opposite the first exit end 50. The double bell like shape provides two flow areas "Aa" and "Ab"
along the length of the impact pad 40. Similar to the previous embodiments, the flared shape of the flow areas provides an increasing cross-section in a direction away form the impact area 52 toward both exit ends 50 and 51. Flow areas "Aa" and "Ab" are both shaped to receive the liquid steel stream flow generated by the incoming ladle stream imp~rting upon the impact area of base 41 and direct it toward the larger cross-sectional 217426~
areas at both exit ends 50 and 51.
Impact pad 40 is similar to the above embodiments in that sidewall 42 also increases in height in a direction away from the impact area 52 toward both exit ends 50 and 51. The difference in height along sidewall 42 causes undercut 47 to be inclined in an upward direction away from the impact area 52 toward both closed exit ends 50 and 51. This gives an undercut height "h" adjacent the impact area that is less than undercut height "H"
at both exit ends. Additionally, the inside surface 44 of sidewall 42 is angled in an oulwdrd direction away from the impact area 52 toward both exit ends 50 and 51, and the opening 49 is also angled in an ~ulward direction from the impact area 52 toward both exit ends 50 and 51. The angle of the inside wall surface 44 gives a sidewall width "w"
adjacent the impact area that is less than a sidewall width "W" at both exit ends.
Likewise, the angle of opening 49 gives an opening width "o" adjacent the impact area that is less than an opening width "O" at both exit ends 50 and 51.
The increasing size of the transverse cross-section along the length of both flow areas "Aa" and "Ab" dissipates the kinetic energy in the liquid steel flow gelleldl~d by the incoming ladle stream. The kinetic energy is dissipated as the liquid steel flow moves from the smallest flow area cross-section adjacent the impact area 52 toward the largest flow area cross-sections at both exit ends 50 and 51. As the kinetic energy is dissipated the velocity of the liquid steel flow is decreased, and the steel exits the impact pad at or near the opening width "O" of opening 49. The liquid steel flow exits the impact pad through opening 49 in an upward direction at a reduced velocity. The slower upward flow pattern avoids short cir~;uilil1g within the tundish and provides effective retention time to improve inclusion float-out to the slag cover on the surface of the heat. Freeze-up and ~kl-lling within the tundish are also reduced because the improved flow uses a larger portion of the tundish for circulating the steel. As a result, a cleaner steel product is produced.
217g26~
Although Figures 7 through 9 show the flow areas "Aa" and "Ab" being the same size and shape, it should be understood that either one of the exit ends 50 or 51 could be larger than the opposite exit end to provide a larger flow area along one half of the impact pad.
Such variations in the flow area enable the impact pad to be designed to meet dirrelellL
flow pattern requirements at opposite ends of a continuous caster tundish.
Each of the above three impact pad embodiments, shown as impact pads 1, 20 and 40 respectively, have vertical sidewalls extending in an upward direction along the periphery of the impact pad base. For example, in the pler~ d embodiment shown in Figures 1-3, impact pad 1 includes a base 2, a top 8 and a sidewall 3. The sidewall extends along the periphery of base 2 between the base and top surface 8. Sidewall 8 includes a shaped inside surface 7 that receives and reverses the direction of a liquid steel flow gellel~t~d by the incoming ladle stream impacting upon base 2. The plane of inside surface 7 intersects the plane of base 2 and the plane of top 8 at a sharp angle of 90 or less to provide a sharp angled undercut along the inside surface of the sidewall.
It has been discovered that if a flow reversing undercut has a sharp angle where the plane of the sidewall intersects the plane of the top, and where the plane of the sidewall intersects the plane of the base of the impact pad, energy (li~ip~tion is greater because the sharp angles create an abrupt direction change that increases friction between the shaped refractory and particles of liquid steel. The increased energy (li~ip~tion gellel~t~d by the sharp angled undercut expends more kinetic energy than the stre~mlin~ undercuts that were taught in the past. As a result the liquid steel flow is discharged from the impact pad at a lower velocity than achieved by using past impact pad designs.
Referring now to Figure 10 of the drawings, impact pad 1 is shown placed within a tundish 60 having a first end wall 61 opposite a second end wall 62. The impact pad is located at the tundish end opposite the discharge well block 63, and the pad is positioned to receive an incoming ladle stream 64 from a nozzle or ladle shroud 65.
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-The incoming ladle stream impacts upon the base 2 and radiates in an oulwald liquid steel flow "F" toward the sidewall 3. Undercut 10 reverses the r~ ting liquid steel flow back into the incoming ladle stream, and friction between the undercut and liquid steel flow as well as friction generated by collisions between the reversed liquid steel flow and the S incoming ladle stream, dissipates the kinetic energy in the liquid steel. The flowing liquid steel is contained within the flow area "A" and it moves in a direction away from the ladle stream impact area toward open end 5. As the liquid steel flow moves along the flow area toward the open end, its cross-section is increased because of the increasing shape of the flow area "A". The increasing cross-section of the liquid steel flow dissipates additional kinetic energy in the steel and further reduces the velocity of the liquid steel being discharged from the impact pad. The steel exits opening 5 at a greater reduced velocity than would be achieved by using only the reversing undercut shape of the impact pad.
Additionally, because the top of the impact pad inclined in an upward direction away from closed end 4 toward open end 5, and because end portions 9 are substantially parallel to the tundish sidewalls 66, the liquid steel flow is forced to move through the steel bath 67 in an upward direction that is substantially parallel to the tundish sidewalls. This causes the liquid steel to flow toward dead zones normally found at the discharge end 62 of a tlln(li~h. This slower upward flow pattern avoids short circuiting within the tundish and provides effective retention time to improve inclusion float-out to the slag cover 68 at the surface of the heat. Freeze-up and ~ lling within the tundish are also reduced because the improved flow uses a larger portion of the tundish for circ~ ting the steel. As a result, a cleaner steel product is produced.
Figure 11 shows impact pad 20 placed within a tundish 70 having at least two discharge nozzles 71. Tundish 70 includes a first end wall 72 opposite a second end wall 73. The impact pad is positioned between the discharge nozzles to receive an incoming ladle stream 74 from a nozzle or ladle shroud 75.
217~26S
The incoming ladle stream impacts upon the base 21 of the pad and ge~ dles a liquid steel flow "F" that radiates ~uLwdld toward the undercut 28 extending along the inside surface of sidewalls 22 and 23. The liquid steel flow is reversed back into the incoming ladle stream by the undercut portion 28. As heretofore disclosed, the r~velsillg feature of undercut 28 dissipates kinetic energy in the liquid steel flow, and the liquid steel flow is contained within the flow areas "Aa" and "Ab" of the impact pad. The liquid steel flow moves in a direction away from the ladle stream impact area toward both open ends 30 and 31. The increasing transverse cross-section along the lengths of the flow areas "Aa" and "Ab" further dissipates kinetic energy within the liquid steel flow, and the steel exits the pad through the open ends 30 and 31 at a greater reduced velocity as explained in the plcl~ d embodiment.
The exiting liquid steel flow "F" enters the main body of the tundish in a direction controlled by incline of undercut 28 and the angle of the inside surface 25. Additionally, because the undercut 28 is inclined in an upward direction, and because end portions 27 are substantially parallel to the tundish sidewalls 78, the liquid steel flow is forced to move through the steel bath 77 in an upward direction that is substantially parallel to the tundish sidewalls. This causes the liquid steel to flow toward dead zones normally found at both discharge ends 72 and 73 of the tlln(li~h. This slower upward flow pattern avoids short circuiting within the tundish and provides effective retention time to improve inclusion float-out to the slag cover 76 on the surface of the heat. Freeze-up and ~-llin~ within the tundish are also reduced because the improved flow uses a larger portion of the tundish for circul~ting the steel. As a result, a cleaner steel product is produced.
Figure 12 shows impact pad 40 placed within a tundish 80 having at least two discharge nozzles 81. Tundish 80 includes a first end wall 82 opposite a second end wall 83. The impact pad is positioned between the discharge nozzles to receive an incoming ladle stream 84 from a nozzle or ladle shroud 85.
The incoming ladle stream impacts upon the base 41 of the pad and radiates ~ulward in a liquid steel flow "F" toward the inside surface 44 of sidewall 42. The liquid steel flow is reversed back into the incoming ladle stream by the undercut portion 47, and as described above, friction between the undercut and liquid steel flow as well as friction generated by collisions between the reversed liquid steel flow and incoming ladle stream, dissipate the kinetic energy in the liquid steel.
As illustrated in the drawing, the flow areas "Aa" and "Ab" contain the liquid steel flow within the impact pad, and the liquid steel flow moves in a direction away from the ladle stream impact area 52 toward the exit closed ends 50 and 51. As the steel flow moves toward the exit ends its cross-section is increased and kinetic energy is further dissipated.
The decrease in kinetic energy causes the velocity of the liquid steel flow to decrease as it moves away from the impact area toward both exit ends, and the liquid steel flow is discharged from the impact pad through opening 49 at opening width "O" located adjacent both exit ends 50 and 51.
The exiting liquid steel flow "F" enters the main body of the tundish in an upward direction at a more reduced velocity than would be achieved by using only the flow reversing undercut feature without the increasing flow areas "Aa" and "Ab". Because the flow moves in a slowed upward direction, the liquid steel moves through the steel bath 87 toward dead zones normally found at both discharge ends 82 and 83 of a tlmtli~h. This slower upward flow pattern avoids short circuiting within the tundish and provides effective retention time to improve inclusion float-out to the slag cover 86 on the surface of the heat. Freeze-up and ~lllin~ within the tundish are also reduced because the improved flow uses a larger portion of the tundish for circul~ting the steel. As a result, a cleaner steel product is produced.
Figure 13 shows the plefell~d embodiment of the impact pad used in combination with at least one additional flow control device 90 placed downstream from the impact pad. The 217426~
slower velocity of the liquid steel flow "F" exiting the open end of the impact pad allows for better flow control of the liquid steel dowl~Llealll of the impact pad. Dam 90 redirects the slower steel upward flow below the slag cover 91 without breaking up the slag cover.
Such a flow path enhances inclusion float-out and produces a cleaner steel product.
While this invention has been described as having a pl~r~lled design, it is understood that it is capable of further modifications, uses, and/or adaptations following in general the principle of the invention and including such depalLules from the present disclosure as come within known or customary practice in the art to which the invention pertains, and 10 as may be applied to the essential features set forth herein, and fall within the scope of the invention limited by the appended claims.
Claims (57)
1. An impact pad comprising:
a) a top having a peripheral surface defining an opening through which a steel stream is directed;
b) a base opposite said top having an impact area upon which said steel stream impacts and over which a steel stream flow advances after impact;
c) a shaped sidewall extending between said base and said top for receiving at least a portion of the steel stream flow and for directing the portion back to the steel stream; and d) at least one exit through which said steel stream flow is discharged from said impact pad, said sidewall, base and top defining a flow area for the steel stream flow, said flow area increasing from said impact area to said exit.
a) a top having a peripheral surface defining an opening through which a steel stream is directed;
b) a base opposite said top having an impact area upon which said steel stream impacts and over which a steel stream flow advances after impact;
c) a shaped sidewall extending between said base and said top for receiving at least a portion of the steel stream flow and for directing the portion back to the steel stream; and d) at least one exit through which said steel stream flow is discharged from said impact pad, said sidewall, base and top defining a flow area for the steel stream flow, said flow area increasing from said impact area to said exit.
2. The impact pad of claim 1 wherein:
a) said sidewall is angled in an outward direction away from said impact area toward said exit to provide said flow area increasing from said impact area to said exit.
a) said sidewall is angled in an outward direction away from said impact area toward said exit to provide said flow area increasing from said impact area to said exit.
3. The impact pad of claim 1 wherein:
a) said top is inclined in an upward direction away from said impact area toward said exit to provide said flow area increasing from said impact area to said exit.
a) said top is inclined in an upward direction away from said impact area toward said exit to provide said flow area increasing from said impact area to said exit.
4. The impact pad of claim 1 wherein:
a) said sidewall is angled in an outward direction away from said impact area toward said exit, and said top is inclined in an upward direction away from said impact area toward said exit to provide said flow area increasing from saidimpact area to said exit.
a) said sidewall is angled in an outward direction away from said impact area toward said exit, and said top is inclined in an upward direction away from said impact area toward said exit to provide said flow area increasing from saidimpact area to said exit.
5. The impact pad of claim 1 wherein:
a) said flow area increases in cross-section in a direction away from said impact area to said exit.
a) said flow area increases in cross-section in a direction away from said impact area to said exit.
6. The impact pad of claim 5 wherein:
a) said flow area continuously increases in cross-section in a direction away from said impact area to said exit.
a) said flow area continuously increases in cross-section in a direction away from said impact area to said exit.
7. The impact pad of claim 1 wherein:
a) said top incudes a peripheral surface defining an opening increasing from said impact area to said exit.
a) said top incudes a peripheral surface defining an opening increasing from said impact area to said exit.
8. The impact pad of claim 1 wherein:
a) said top incudes a peripheral surface defining an opening continuously increasing from said impact area to said exit.
a) said top incudes a peripheral surface defining an opening continuously increasing from said impact area to said exit.
9. The impact pad of claim 1 wherein:
a) said sidewall includes a closed end and an open end opposite said closed end;
and b) said top is inclined in an upward direction away from said closed end towardsaid open end, said open end having a dimension "H" between said base and said top greater than a dimension "h" between said base and said top adjacent said impact area.
a) said sidewall includes a closed end and an open end opposite said closed end;
and b) said top is inclined in an upward direction away from said closed end towardsaid open end, said open end having a dimension "H" between said base and said top greater than a dimension "h" between said base and said top adjacent said impact area.
10. The impact pad of claim 1 wherein:
a) said sidewall includes;
i) a closed end and an open end opposite said closed end, and ii) at least one inside surface angled in an outward direction away from said closed end toward said open end, said open end having a dimension "W"
between the bounds of said sidewall greater than a dimension "w" between the bounds of said sidewall adjacent said impact area.
a) said sidewall includes;
i) a closed end and an open end opposite said closed end, and ii) at least one inside surface angled in an outward direction away from said closed end toward said open end, said open end having a dimension "W"
between the bounds of said sidewall greater than a dimension "w" between the bounds of said sidewall adjacent said impact area.
11. The impact pad of claim 10 wherein said at least one inside surface includes an end portion adjacent said open end, said end portion being non - parallel to said at least one inside surface.
12. The impact pad of claim 1 wherein:
a) said sidewall includes;
i) a closed end and an open end opposite said closed end, and ii) at least one inside surface angled in an outward direction away from said closed end toward said open end, said open end having a dimension "W"
between the bounds of said sidewall greater than a dimension "w" between the bounds of said sidewall adjacent said impact area; and b) said top is inclined in an upward direction away from said closed end toward said open end, said open end having a dimension "H" between said base and said top greater than a dimension "h" between said base and said top adjacent said impact area.
a) said sidewall includes;
i) a closed end and an open end opposite said closed end, and ii) at least one inside surface angled in an outward direction away from said closed end toward said open end, said open end having a dimension "W"
between the bounds of said sidewall greater than a dimension "w" between the bounds of said sidewall adjacent said impact area; and b) said top is inclined in an upward direction away from said closed end toward said open end, said open end having a dimension "H" between said base and said top greater than a dimension "h" between said base and said top adjacent said impact area.
13. The impact pad of claim 12 wherein said at least one inside surface includes an end portion adjacent said open end, said end portion being non - parallel to said at least one inside surface.
14. The impact pad of claim 1 comprising:
a) a first exit through which a portion of said steel stream flow is discharged from said impact pad, and a second exit through which a portion of said steel stream flow is discharged from said impact pad, said sidewall, base and top defining a first flow area increasing from said impact area to said first exit and a second flow area increasing from said impact area to said second exit.
a) a first exit through which a portion of said steel stream flow is discharged from said impact pad, and a second exit through which a portion of said steel stream flow is discharged from said impact pad, said sidewall, base and top defining a first flow area increasing from said impact area to said first exit and a second flow area increasing from said impact area to said second exit.
15. The impact pad of claim 14 wherein:
a) said sidewall is angled in an outward direction away from said impact area toward said first exit to provide said first flow area increasing from said impact area to said first exit; and b) said sidewall is angled in an outward direction away from said impact area toward said second exit to provide said second flow area increasing from said impact area to said second exit.
a) said sidewall is angled in an outward direction away from said impact area toward said first exit to provide said first flow area increasing from said impact area to said first exit; and b) said sidewall is angled in an outward direction away from said impact area toward said second exit to provide said second flow area increasing from said impact area to said second exit.
16. The impact area of claim 14 wherein:
a) said top is inclined in an upward direction away from said impact area towardsaid first exit to provide said first flow area increasing from said impact areato said first exit; and b) said top is inclined in an upward direction away from said impact area towardsaid second exit to provide said second flow area increasing from said impact area to said second exit.
a) said top is inclined in an upward direction away from said impact area towardsaid first exit to provide said first flow area increasing from said impact areato said first exit; and b) said top is inclined in an upward direction away from said impact area towardsaid second exit to provide said second flow area increasing from said impact area to said second exit.
17. The impact pad of claim 14 wherein:
a) said sidewall is angled in an outward direction away from said impact area toward said first exit, and said top is inclined in an upward direction away from said impact area toward said first exit to provide said first flow area increasing from said impact area to said first exit; and b) said sidewall is angled in an outward direction away from said impact area toward said second exit, and said top is inclined in an upward direction away from said impact area toward said second exit to provide said second flow area increasing from said impact area to said second exit.
a) said sidewall is angled in an outward direction away from said impact area toward said first exit, and said top is inclined in an upward direction away from said impact area toward said first exit to provide said first flow area increasing from said impact area to said first exit; and b) said sidewall is angled in an outward direction away from said impact area toward said second exit, and said top is inclined in an upward direction away from said impact area toward said second exit to provide said second flow area increasing from said impact area to said second exit.
18. The impact pad of claim 14 wherein:
a) said first flow area increases in cross-section in a direction away from said impact area toward said first exit; and b) said second flow area increases in cross-section in a direction away from said impact area toward said second exit.
a) said first flow area increases in cross-section in a direction away from said impact area toward said first exit; and b) said second flow area increases in cross-section in a direction away from said impact area toward said second exit.
19. The impact pad of claim 18 wherein:
a) said first flow area continuously increases in a direction away from said impact area toward said first exit; and b) said second flow area continuously increases in a direction away from said impact area toward said second exit.
a) said first flow area continuously increases in a direction away from said impact area toward said first exit; and b) said second flow area continuously increases in a direction away from said impact area toward said second exit.
20. The impact pad of claim 14 wherein:
a) said top includes a peripheral surface defining an opening increasing from said impact area toward said first exit and increasing from said impact area toward said second exit.
a) said top includes a peripheral surface defining an opening increasing from said impact area toward said first exit and increasing from said impact area toward said second exit.
21. The impact pad of claim 14 wherein:
a) said top includes a peripheral surface defining an opening continuously increasing from said impact area toward said first exit and continuously increasing from said impact area toward said second exit.
a) said top includes a peripheral surface defining an opening continuously increasing from said impact area toward said first exit and continuously increasing from said impact area toward said second exit.
22. The impact pad of claim 14 wherein:
a) said sidewall includes a first open end and a second open end opposite said first open end; and b) said top is inclined in an upward direction away from said impact area towardsaid first open end, and said top is inclined in an upward direction away from said impact area toward said second open end, said first open end and said second open end both having a dimension "H" between said base and said top greater than a dimension "h" between said base and said top adjacent said impact area.
a) said sidewall includes a first open end and a second open end opposite said first open end; and b) said top is inclined in an upward direction away from said impact area towardsaid first open end, and said top is inclined in an upward direction away from said impact area toward said second open end, said first open end and said second open end both having a dimension "H" between said base and said top greater than a dimension "h" between said base and said top adjacent said impact area.
23. The impact pad of claim 22 wherein said first open end dimension "H" is not equal to said second open end dimension "H".
24. The impact pad of claim 14 wherein:
a) said sidewall includes a first open end and a second open end opposite said first open end; and b) said sidewall includes at least one inside surface angled in an outward direction away from said impact area toward said first open end, and at least one inside surface angled in an outward direction away from said impact area toward said second open end, said first open end and said second open end both having a dimension "W" between the bounds of said sidewall greater than a dimension "w" between the bounds of said sidewall adjacent said impact area.
a) said sidewall includes a first open end and a second open end opposite said first open end; and b) said sidewall includes at least one inside surface angled in an outward direction away from said impact area toward said first open end, and at least one inside surface angled in an outward direction away from said impact area toward said second open end, said first open end and said second open end both having a dimension "W" between the bounds of said sidewall greater than a dimension "w" between the bounds of said sidewall adjacent said impact area.
25. The impact pad of claim 24 wherein said first open end dimension "W" is not equal to said second open end dimension "W".
26. The impact pad of claim 24 wherein said at least one inside surface includes an end portion adjacent at least one of said first open end or said second open end, said end portion being non - parallel to said at least one inside surface.
27. The impact pad of claim 14 wherein:
a) said sidewall includes;
i) a first open end and a second open end opposite said first open end, and ii) at least one inside surface angled in an outward direction away from said impact area toward said first open end, and at least one inside surface angled in an outward direction away from said impact area toward said second open end, said first open end and said second open end both having a dimension "W" between the bounds of said sidewall greater than a dimension "w" between the bounds of said sidewall adjacent said impact area; and b) said top is inclined in an upward direction away from said impact area towardsaid first open end and in an upward direction away from said impact area toward said second open end, said first open end and said second open end both having a dimension "H" between said base and said top greater than a dimension "h" between said base and said top adjacent said impact area.
a) said sidewall includes;
i) a first open end and a second open end opposite said first open end, and ii) at least one inside surface angled in an outward direction away from said impact area toward said first open end, and at least one inside surface angled in an outward direction away from said impact area toward said second open end, said first open end and said second open end both having a dimension "W" between the bounds of said sidewall greater than a dimension "w" between the bounds of said sidewall adjacent said impact area; and b) said top is inclined in an upward direction away from said impact area towardsaid first open end and in an upward direction away from said impact area toward said second open end, said first open end and said second open end both having a dimension "H" between said base and said top greater than a dimension "h" between said base and said top adjacent said impact area.
28. The impact pad of claim 27 wherein said first open end dimension "H" is not equal to said second open end dimension "H".
29. The impact pad of claim 27 wherein said first open end dimension "W" is not equal to said second open end dimension "W".
30. The impact pad of claim 27 wherein said at least one slanted inside surface includes an end portion adjacent at least one of said first open end or said second open end, said end portion being non - parallel to said at least one inside surface.
31. The impact pad of claim 1 wherein:
a) said sidewall extends continuously between said base and said top; and b) said opening through which said steel stream is directed includes a first exit end and a second exit end opposite said first exit end for discharging said steel stream flow from said impact pad.
a) said sidewall extends continuously between said base and said top; and b) said opening through which said steel stream is directed includes a first exit end and a second exit end opposite said first exit end for discharging said steel stream flow from said impact pad.
32. The impact pad of claim 31 wherein:
a) said sidewall is angled in an outward direction away from said impact area toward said first exit end to provide said first flow area increasing from said impact area to said first exit end; and b) said sidewall is angled in an outward direction away from said impact area toward said second exit end to provide said second flow area increasing from said impact area to said second exit end.
a) said sidewall is angled in an outward direction away from said impact area toward said first exit end to provide said first flow area increasing from said impact area to said first exit end; and b) said sidewall is angled in an outward direction away from said impact area toward said second exit end to provide said second flow area increasing from said impact area to said second exit end.
33. The impact area of claim 31 wherein:
a) said top is inclined in an upward direction away from said impact area towardsaid first exit end to provide said first flow area increasing from said impact area to said first exit end; and b) said top is inclined in an upward direction away from said impact area towardsaid second exit end to provide said second flow area increasing from said impact area to said second exit end.
a) said top is inclined in an upward direction away from said impact area towardsaid first exit end to provide said first flow area increasing from said impact area to said first exit end; and b) said top is inclined in an upward direction away from said impact area towardsaid second exit end to provide said second flow area increasing from said impact area to said second exit end.
34. The impact pad of claim 31 wherein:
a) said sidewall is angled in an outward direction away from said impact area toward said first exit end, and said top is inclined in an upward direction awayfrom said impact area toward said first exit end to provide said first flow areaincreasing from said impact area to said first exit end; and b) said sidewall is angled in an outward direction away from said impact area toward said second exit end, and said top is inclined in an upward direction away from said impact area toward said second exit end to provide said second flow area increasing from said impact area to said second exit end.
a) said sidewall is angled in an outward direction away from said impact area toward said first exit end, and said top is inclined in an upward direction awayfrom said impact area toward said first exit end to provide said first flow areaincreasing from said impact area to said first exit end; and b) said sidewall is angled in an outward direction away from said impact area toward said second exit end, and said top is inclined in an upward direction away from said impact area toward said second exit end to provide said second flow area increasing from said impact area to said second exit end.
35. The impact pad of claim 31 wherein:
a) said first flow area increases in cross-section in a direction away from said impact area toward said first exit end; and b) said second flow area increases in cross-section in a direction away from said impact area toward said second exit end.
a) said first flow area increases in cross-section in a direction away from said impact area toward said first exit end; and b) said second flow area increases in cross-section in a direction away from said impact area toward said second exit end.
36. The impact pad of claim 35 wherein:
a) said first flow area continuously increases in a direction away from said impact area toward said first exit end; and b) said second flow area continuously increases in a direction away from said impact area toward said second exit end.
a) said first flow area continuously increases in a direction away from said impact area toward said first exit end; and b) said second flow area continuously increases in a direction away from said impact area toward said second exit end.
37. The impact pad of claim 31 wherein:
a) said top includes a peripheral surface defining an opening increasing from said impact area toward said first exit end and increasing from said impact area toward said second exit end.
a) said top includes a peripheral surface defining an opening increasing from said impact area toward said first exit end and increasing from said impact area toward said second exit end.
38. The impact pad of claim 31 wherein:
a) said top includes a peripheral surface defining an opening continuously increasing from said impact area toward said first exit end and continuously increasing from said impact area toward said second exit end.
a) said top includes a peripheral surface defining an opening continuously increasing from said impact area toward said first exit end and continuously increasing from said impact area toward said second exit end.
39. The impact pad of claim 31 wherein:
a) said top is inclined in an upward direction away from said impact area toward said first exit end, and said top is inclined in an upward direction away from said impact area toward said second exit end, said first exit end and said second exit end both having a dimension "H" between said base and said top greater than a dimension "h" between said base and said top adjacent said impact area.
a) said top is inclined in an upward direction away from said impact area toward said first exit end, and said top is inclined in an upward direction away from said impact area toward said second exit end, said first exit end and said second exit end both having a dimension "H" between said base and said top greater than a dimension "h" between said base and said top adjacent said impact area.
40. The impact pad of claim 39 wherein said first exit end dimension "H" is not equal to said second exit end dimension "H".
41. The impact pad of claim 31 wherein:
a) said sidewall includes at least one inside surface angled in an outward direction away from said impact area toward said first exit end, and at least one inside surface angled in an outward direction away from said impact area toward said second exit end, said first exit end and said second exit end both having a sidewall dimension "W" greater than a sidewall dimension "w" adjacent said impact area.
a) said sidewall includes at least one inside surface angled in an outward direction away from said impact area toward said first exit end, and at least one inside surface angled in an outward direction away from said impact area toward said second exit end, said first exit end and said second exit end both having a sidewall dimension "W" greater than a sidewall dimension "w" adjacent said impact area.
42. The impact pad of claim 41 wherein said first exit end dimension "W" is not equal to said second exit end dimension "W".
43. The impact pad of claim 41 wherein said at least one inside surface includes an end portion adjacent at least one of said first exit end or said second exit end, said end portion being non - parallel to said at least one inside surface.
44. The impact pad of claim 31 wherein:
a) said sidewall includes at least one inside surface angled in an outward direction away from said impact area toward said first exit end, and at least one inside surface angled in an outward direction away from said impact area toward said second exit end, said first exit end and said second exit end both having a sidewall dimension "W" greater than a sidewall dimension "w" adjacent said impact area;
b) said top is inclined in an upward direction away from said impact area towardsaid first exit end, and said top is inclined in an upward direction away from said impact area toward said second exit end, said first exit end and said second exit end both having a dimension "H" between said base and said top greater than a dimension "h" between said base and said top adjacent said impact area; and c) said top includes a peripheral surface defining an opening increasing from said impact area toward said first exit end and increasing from said impact area toward said second exit end, said first exit end and said second exit end both having an opening dimension "O" greater than an opening dimension "o"
adjacent said impact area.
a) said sidewall includes at least one inside surface angled in an outward direction away from said impact area toward said first exit end, and at least one inside surface angled in an outward direction away from said impact area toward said second exit end, said first exit end and said second exit end both having a sidewall dimension "W" greater than a sidewall dimension "w" adjacent said impact area;
b) said top is inclined in an upward direction away from said impact area towardsaid first exit end, and said top is inclined in an upward direction away from said impact area toward said second exit end, said first exit end and said second exit end both having a dimension "H" between said base and said top greater than a dimension "h" between said base and said top adjacent said impact area; and c) said top includes a peripheral surface defining an opening increasing from said impact area toward said first exit end and increasing from said impact area toward said second exit end, said first exit end and said second exit end both having an opening dimension "O" greater than an opening dimension "o"
adjacent said impact area.
45. The impact pad of claim 44 wherein said first exit end dimension "H" is not equal to said second exit end dimension "H".
46. The impact pad of claim 44 wherein said first exit end dimension "W" is not equal to said second exit end dimension "W".
47. The impact pad of claim 44 wherein said first exit end dimension "O" is not equal to said second exit end dimension "O".
48. An impact pad comprising:
a) a top having a peripheral surface defining an opening through which a steel stream is directed;
b) a base opposite said top having an impact area upon which said steel stream impacts and over which a steel stream flow advances after impact;
c) a shaped sidewall extending between said base and said top for receiving at least a portion of the steel stream flow and for directing the portion back to the steel stream, said shaped sidewall intersecting said base at a sharp angle, and said shaped sidewall intersecting said top at a sharp angle; and d) at least one exit through which said steel stream flow is discharged from said impact pad.
a) a top having a peripheral surface defining an opening through which a steel stream is directed;
b) a base opposite said top having an impact area upon which said steel stream impacts and over which a steel stream flow advances after impact;
c) a shaped sidewall extending between said base and said top for receiving at least a portion of the steel stream flow and for directing the portion back to the steel stream, said shaped sidewall intersecting said base at a sharp angle, and said shaped sidewall intersecting said top at a sharp angle; and d) at least one exit through which said steel stream flow is discharged from said impact pad.
49. The impact pad of claim 48 wherein:
a) said sidewall, base and top defining a flow area for the steel stream flow, said flow area increasing from said impact area to said exit.
a) said sidewall, base and top defining a flow area for the steel stream flow, said flow area increasing from said impact area to said exit.
50. A method for dissipating kinetic energy in a liquid steel flow in a tundish, the steps of the method comprising:
a) directing a steel stream to impact upon a base of an impact pad having an impact area, said base, a shaped sidewall and a top of said impact pad defining a flow area increasing from said impact area to at least one exit;
b) receiving within said flow area a steel stream flow generated by said steel stream impacting upon said base;
c) causing said steel stream flow to move toward said at least one exit, said flow area increasing from said impact area to said at least one exit dissipating kinetic energy in said steel stream flow; and d) discharging said steel stream flow having dissipated kinetic energy through said at least one exit into said tundish.
a) directing a steel stream to impact upon a base of an impact pad having an impact area, said base, a shaped sidewall and a top of said impact pad defining a flow area increasing from said impact area to at least one exit;
b) receiving within said flow area a steel stream flow generated by said steel stream impacting upon said base;
c) causing said steel stream flow to move toward said at least one exit, said flow area increasing from said impact area to said at least one exit dissipating kinetic energy in said steel stream flow; and d) discharging said steel stream flow having dissipated kinetic energy through said at least one exit into said tundish.
51. The method of claim 50 including a further step comprising:
a) inclining said top in an upward direction away from said impact area to provide said flow area increasing from said impact area to said at least one exit.
a) inclining said top in an upward direction away from said impact area to provide said flow area increasing from said impact area to said at least one exit.
52. The method of claim 50 including a further step comprising:
a) slanting said shaped sidewall in an outward direction away from said impact area to provide said flow area increasing from said impact area to said at leastone exit
a) slanting said shaped sidewall in an outward direction away from said impact area to provide said flow area increasing from said impact area to said at leastone exit
53. The method of claim 50 including a further step comprising:
a) inclining said top in an upward direction away from said impact area, and slanting said shaped sidewall in an outward direction away from said impact area to provide said flow area increasing from said impact pad to said at least one exit.
a) inclining said top in an upward direction away from said impact area, and slanting said shaped sidewall in an outward direction away from said impact area to provide said flow area increasing from said impact pad to said at least one exit.
54. The method of claim 50 including a further step comprising:
a) discharging said steel stream flow having dissipated kinetic energy through afirst exit and a second exit opposite said first exit into said tundish.
a) discharging said steel stream flow having dissipated kinetic energy through afirst exit and a second exit opposite said first exit into said tundish.
55. The method of claim 50 including the further steps comprising:
a) directing said steel stream through an opening extending through said top defining said flow area of said impact pad, and where the shaped sidewall defining said flow area is continuous; and b) discharging said steel stream flow through a first exit end and a second exit end opposite said first exit end of said opening extending through said top.
a) directing said steel stream through an opening extending through said top defining said flow area of said impact pad, and where the shaped sidewall defining said flow area is continuous; and b) discharging said steel stream flow through a first exit end and a second exit end opposite said first exit end of said opening extending through said top.
56. The method of claim 50 including the further steps comprising:
a) inclining said top in an upward direction away from said impact area toward at least one exit, and slanting said shaped sidewall in an outward direction away from said impact area toward at least one exit to provide at least one saidflow area increasing from said impact pad toward at least one exit; and b) slanting at least one side of said opening extending through said top in an outward direction away from said impact area toward at least one exit end to provide at least one opening portion increasing from said impact pad toward at least one exit end.
a) inclining said top in an upward direction away from said impact area toward at least one exit, and slanting said shaped sidewall in an outward direction away from said impact area toward at least one exit to provide at least one saidflow area increasing from said impact pad toward at least one exit; and b) slanting at least one side of said opening extending through said top in an outward direction away from said impact area toward at least one exit end to provide at least one opening portion increasing from said impact pad toward at least one exit end.
57. The method of claim 50 including a further step comprising:
a) providing at least one flow control device downstream from said impact pad to control the direction of said liquid steel flow discharged from said at leastone exit of said impact pad.
a) providing at least one flow control device downstream from said impact pad to control the direction of said liquid steel flow discharged from said at leastone exit of said impact pad.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US51454795A | 1995-08-14 | 1995-08-14 | |
| US08/514,547 | 1995-08-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2174266A1 true CA2174266A1 (en) | 1997-02-15 |
Family
ID=24047672
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002174266A Abandoned CA2174266A1 (en) | 1995-08-14 | 1996-04-16 | Tundish impact pad and method |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2174266A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107073574A (en) * | 2014-08-15 | 2017-08-18 | 安赛乐米塔尔研究与发展有限责任公司 | Impact pad includes the cast disk and equipment and its application method of impact pad |
-
1996
- 1996-04-16 CA CA002174266A patent/CA2174266A1/en not_active Abandoned
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107073574A (en) * | 2014-08-15 | 2017-08-18 | 安赛乐米塔尔研究与发展有限责任公司 | Impact pad includes the cast disk and equipment and its application method of impact pad |
| CN107073574B (en) * | 2014-08-15 | 2020-06-26 | 安赛乐米塔尔研究与发展有限责任公司 | Impact pad, casting tray and apparatus including impact pad, and method of using same |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |
Effective date: 19990416 |