CN107073574A - Impact pad includes the cast disk and equipment and its application method of impact pad - Google Patents

Abstract

The present invention provides cast disk impact pad, the cast disk comprising the cast disk impact pad and its application method and the component comprising impact pad and cast disk.Cast disk impact pad is characterised by including：Base portion, the base portion has base surface, and the base surface includes taper shock surface region, and the taper shock surface region forms summit；Side wall；And roof, the roof is extended internally relative to side wall, to terminate inside edge, and inward flange formation nozzle part opening, the nozzle part opening is opened with vertex spacings above summit and is centered about relative to summit.Roof includes antelabium, and the antelabium is sloped inwardly and downwardly radially toward taper shock surface.

Description

Impact pad, pouring pan and apparatus including impact pad, and method of use thereof

Cross-references and priority claims to related patent applications

This application claims priority to US Provisional Application No. 62/037,949, filed August 15, 2014, the entire disclosure of which is incorporated herein by reference.

technical field

The present invention relates to impingement pads for use in steelmaking, and in particular to tundish impact pads adapted to reduce turbulence and bath surface disruption produced by the ladle flow of molten steel fed into the tundish of a continuous casting machine. The invention also relates to tundishes and apparatus including impact pads, and methods of using impact pads, tundishes and apparatus.

Background technique

Steel casting machines are equipment used to perform continuous casting, also known in the art as chain casting. Continuous casting involves transferring molten steel from a steelmaking furnace into a ladle. Molten steel is fed from the ladle through a ladle shroud (also known as a ladle shroud) which extends into a container or vessel called a tundish. Molten steel is usually fed in a continuous or semi-continuous liquid stream into a pool of molten steel contained in a tundish. The tundish is generally used as a reservoir from which molten steel can be fed into the casting machine mold without interruption or undesired shutdown. To protect the molten steel in the tundish from undesired chemical reactions (eg excessive oxidation) and airborne particulate matter, a protective slag cap/layer or "flux" is allowed to form at the surface of the molten steel pool.

The surface requirements and cleanliness standards of modern high-quality steel products have a very low tolerance for impurities and chemical changes. Impurities and chemical changes are caused by turbulence created by ladle flow introduced by the molten steel fed into the tundish. Certain tundish designs for receiving liquid steel from a ladle shroud result in unfavorable fluid flow conditions within the tundish, such as turbulent flow, and promote extremely free surface flow. For example, fluid flow from an incoming ladle flow may reflect from the flat tundish floor and side walls towards the surface of the liquid steel. This resulting fluid flow causes turbulent boiling action, massive waves, and sputtering at the surface of the steel bath.

For example, Fig. 10 shows a longitudinal cross-section of a single-chain tundish 1 with an asymmetric fluid flow 9a. The ladle shroud 7 is shown adjacent to the end wall 3 opposite the block (not shown in Figures 10 and 11 ). Water flow modeling studies have shown that the fluid flow generated by the incoming ladle flow 8 from the ladle shroud 7 is reflected from the flat tundish floor 4 in an upward direction towards the surface of the liquid steel. If the fluid flow is restricted by the tundish walls 2 and 3, the restricted fluid flow is forced to travel upwards along the surface of the walls 2,3. This upward flow follows the circular path 9c and creates an upward surge along the surface of the end wall 3 and a downward flow around the ladle shroud 7 . The upward surge of the circular flow 9c causes excessive turbulence at the surface of the molten pool. These extremely free surface movements in the tundish create a phenomenon known as "eye opening", whereby the protective slag cover 6 on top of the steel bath ruptures. The ruptured slag cover 6 exposes the liquid steel to the surrounding environment and creates conditions favorable to changing the chemistry of the steel bath and creating inclusions in the steel bath. The chemical changes typically involve loss of aluminum from the molten pool and/or oxygen and nitrogen uptake into the steel molten pool with subsequent surface re-oxidation. Re-oxidation and other undesired reactions may, for example, introduce excess amounts of alumina, manganese sulphides and calcium sulphides into the steel bath. Additionally, the downward flow around the ladle shroud 7 creates shear forces and vortices, and traps and pulls broken particles 10 from the broken flux cover 6 down into the liquid steel bath. These fractured particles 10 are eventually discharged from the tundish with the molten steel and produce inclusions in the final steel product.

Chemical changes and inclusions ultimately degrade steel quality and are the main reason for limiting high value steel grades such as HIC and armor plate grades. In addition, the splashing of high-temperature liquid steel on the wall of the pouring pan may pose a safety hazard to the operator. With conventional equipment, problems can also arise regarding lack of steel bath temperature homogeneity and insufficient residence time to allow contained particulate matter to float onto the protective slag cover where the particulate matter can be isolated from the liquid steel and/or separately.

Various attempts have been made to reduce or eliminate surface turbulence in the tundish of a continuous caster in order to improve the quality of the final steel product. These attempts have included various dams and weirs that redirect the ladle fluid flow away from the surface of the molten steel bath. Although some known fluid flow control devices have been somewhat successful in controlling fluid flow and reducing surface turbulence, such control devices are insufficient for the demands of high quality steel and/or tend to cause operational problems such as questions like those mentioned above.

Contents of the invention

According to a first aspect of the present invention there is provided a tundish impact pad, the tundish impact pad is characterized by comprising: a base having a base surface comprising a conical impact surface region, the conical impact surface The region forms an apex; side walls; and a top wall extending inwardly relative to the side walls to terminate at an inner edge forming a mouth opening spaced above and opposite to the apex. Centered on the vertex. The top wall includes a lip that slopes radially inward and downward toward the tapered impact surface.

A second aspect of the present invention provides an apparatus characterized by comprising: a continuous casting machine tundish for containing a reservoir of molten metal having fluid flow; and tundish impact pads in tundishes of continuous casting machines. The pouring pan impact pad includes: a base having a base surface including a tapered impact surface area forming an apex; side walls; and a top wall extending inwardly relative to the side walls , to terminate at an inner edge forming a mouth opening spaced above and centrally located relative to the apex from the apex. The top wall includes a lip that slopes radially inward and downward toward the tapered impact surface.

A third aspect of the present invention provides a chain casting method or molten steel processing method in which an incoming ladle flow of molten liquid steel is fed into a continuous casting machine tundish and is allowed to flow through tundish impact pads The mouth impacts the conical impact surface area of the tundish impact pad before opening into the tundish reservoir. The tundish impact pad includes a base having a base surface, side walls, and a top wall extending inwardly relative to the side walls to terminate at an inner edge forming a mouth opening in a tapered The apex of the impact surface area is spaced above and centrally located relative to the apex. The top wall includes a lip that slopes radially inward and downward toward the tapered impact surface.

According to an embodiment of the various aspects described herein, the top wall of the tundish impact pad is characterized by comprising a lower surface which, together with the base surface and the continuous sidewall inner surface of the sidewall, forms a continuous annular cavity, the continuous annular cavity The chamber is configured to reduce turbulence of molten liquid steel introduced into the ladle flow.

According to a further embodiment of the above aspect, the conical impact surface region has an axis passing through the apex, about which axis the conical impact surface region is rotationally symmetric.

According to a further embodiment of the above aspect, the conical impact surface region has a linear profile.

According to another embodiment of the above aspect, the conical impact surface area has a cone angle measured from a horizontal plane on which the outer periphery of the conical impact surface area is located to an inclined plane on which the conical impact surface area is located, and the cone angle is in the range of About 15 degrees to about 25 degrees.

According to another embodiment of the above aspect, the lip has a downward lip angle measured from the horizontal plane to the lower surface of the lip, the downward lip angle ranging from about 20 degrees to about 25 degrees.

According to another embodiment of the above aspect, the continuous annular chamber has a radius of curvature of about 30mm.

According to another embodiment of the above aspect, the protrusions, for example hemispherical protrusions, are distributed around the lower surface area of the lip.

The above-described embodiments may be implemented in any combination with each other.

Other aspects and embodiments of the invention, including devices, assemblies, devices, articles of manufacture, methods of making and using, processes, etc., forming a part of the invention will become more apparent upon reading the following detailed description of the exemplary embodiments. obvious.

Description of drawings

The accompanying drawings are incorporated in and constitute a part of this specification. The drawings, together with the foregoing general description and the detailed description of exemplary embodiments and methods given below, serve to explain the principles of the invention. In the attached picture:

Figure 1 is a longitudinal cross-sectional front perspective view of a single chain caster tundish including impact pads according to one embodiment of the present invention;

Fig. 2 is a longitudinal cross-sectional front view of the pouring pan of the single chain casting machine of Fig. 1;

Figure 3 is a front perspective view of the impact pad of the embodiment shown in Figure 1;

Figure 4 is a plan view of the impact pad of Figure 3;

Figure 5 is a cross-sectional view taken along the line V-V of Figure 4;

Figure 6 is a cutaway side perspective view of the impact pad of Figures 3-5;

Figure 7 is a cross-sectional end view taken from the point of view of the arrow on the right side of Figures 1 and 2, showing the flow profile of incoming liquid steel directed through a shroud centrally positioned above the impact pad;

8 is a cross-sectional view of an impact pad according to another embodiment of the present invention;

Fig. 9 is a bottom sectional view taken along line IX-IX of Fig. 8;

Figures 10 and 11 reproduce US Patent No. Re. 35,685, wherein Figure 10 is a longitudinal cross-sectional view of a water flow model study pouring tray, and Figure 11 is a transverse cross-sectional view taken along line XI-XI of Figure 10 .

detailed description

Reference will now be made in detail to the exemplary embodiments and methods, as illustrated in the drawings, wherein like reference numerals represent like or corresponding parts throughout. It should be noted, however, that the invention in its broader aspects is not necessarily limited to the specific details, representative materials and methods, and illustrative examples shown and described in connection with the exemplary embodiments and methods.

A tundish for a chain casting machine according to an exemplary embodiment is indicated generally at 10 in FIGS. 1 and 2 . Although a single chain casting machine is shown herein, it should be understood that embodiments of the invention may be practiced in conjunction with double chain or other multi-chain casting machines. An example of a multi-chain caster design (albeit with different impact pads) is shown in Figure 10 of US Patent No. RE35,685. The tundish 10 comprises tundish end walls 12 and 14, front and rear side walls of the tundish (no reference numerals) and a tundish floor 16 extending between the end walls 12, 14 and the side walls and Connected (or integrally combined) with end walls and side walls. The tundish end walls 12, 14 and floor 16 together form a chamber or reservoir 18 for receiving and holding a pool of molten steel. The tundish impact pad 20 is positioned in the reservoir 18 , for example closer to the end wall 12 than to the end wall 14 . Positioned above the tundish impingement pad 20 is a lower portion of the ladle shroud 22 for directing an incoming ladle stream 24 ( FIG. 7 ) of molten steel into the impingement pad 20 . A ladle shroud 22 is shown passing through the top of the molten steel bath, the end of the ladle shroud 22 being spaced above and coaxially with the tundish impact pad 20 Centered. The flow of molten steel and the structure and function of impact pad 20 are discussed in further detail below.

The pouring tray 10 also includes a weir 26 which divides the pouring tray 10 into left and right (first and second) compartments 18a and 18b respectively, in Figures 1 and 2 the impact pad 20 is in the right compartment In 18a, it is located on the bottom plate 16 of the pouring pan. The bottom of the weir 26 includes a channel 26a for allowing fluid communication between the liquid steel in the left and right compartments 18a, 18b. A diffuser 28 is positioned on the tundish floor 16 in the right compartment 18a between the weir 26 and the tundish impact pad 20 . A bank 30 with a plurality of upwardly sloping (right to left in the direction of flow) cylindrical channels 30a rests against the tundish floor 16 in the left compartment 18b. On the side of the dike 30 opposite the weir 26 , the stopper rod 32 is aligned with an outlet port or pouring pan brick 34 through which liquid steel exits the pouring pan 10 . The upward and downward movement of the stopper rod 32 controls the flow of molten steel from the tundish 10 and into the casting machine (not shown).

The tundish impact pad 20 may be made of one or more materials suitable for use in a casting machine tundish for molten steel processing. Typically, such materials have high impact and corrosion resistance, high hot strength and fire resistance, and good castability. Examples of suitable materials are metals, ceramics and ceramic-coated sand. As specific but non-limiting examples, low moisture, high alumina castable compositions such as Narcon 70 Castable and coarse high alumina, low cement castable compositions such as 70C Plus) is a refractory material suitable for use as the tundish impact pad 20. According to product information: Narcon 70 Castable contains (calcined basis) 26.9% of silicon dioxide (SiO ₂ ), 69.8% of aluminum oxide (Al ₂ O ₃ ), 1.7% of titanium dioxide (TiO ₂ ), 0.8% of iron oxide (Fe ₂ O ₃ ), 0.7% lime (CaO), and 0.1% alkali (Na ₂ O); 70C Plus contains (calcined basis) 27.5% silicon dioxide (SiO ₂ ), 67.3% aluminum oxide (Al ₂ O ₃ ), 2.1% titanium dioxide (TiO ₂ ), 1.2% iron oxide (Fe ₂ O ₃ ) , 1.6% lime (CaO), 0.1% magnesium oxide (MgO), and 0.2% alkali metal (Na ₂ O+K ₂ O). The body portion of the tundish impact pad 20 may be coated with a corrosion resistant material to form a corrosion resistant coating for receiving and contacting the incoming ladle flow 24 . Erosion-resistant coatings can be made of moderately emissive materials such as zirconia, yttrium oxide, silicon carbide, high reflectivity materials such as aluminum and alumina, or high temperature non-oxidizing lubricants such as boron nitride.

Referring to the embodiment shown in Figures 3-6, the tundish impact pad 20 includes a circular base 40 (relative to a plan or bottom view). The base 40 includes a top base surface having a conical impact surface area 42 concentrically surrounding the conical impact surface area 42 and an adjoining adjacent annular base surface area 44 . In the illustrated embodiment, the conical impact surface region 42 is not truncated. Optionally, the top of the conical impact surface region 42 may be slightly rounded, but still retain the conical shape. As best shown in FIG. 5 , the tapered impact surface region 42 extends upwardly to terminate at an apex or tip 46 . The conical impact surface region 42 is rotationally symmetric about an imaginary axis Az ( FIG. 5 ) passing through the apex 46 . In the illustrated embodiment, the tapered impact surface region 42 has a linear profile or cross-section, as best shown in FIG. 5 . The base of the linear profile of the tapered impact surface area 42 terminates at an outer perimeter 48 which is adjacent to and adjoins the radially inner edge of the annular base surface area 44 . The top of the linear profile of the conical impact surface area 42 ends at a point corresponding to the apex 46, which coincides with the axis Az. The annular base surface area 44 may be at least partially flat and in a horizontal plane parallel to the bottom surface 40 a of the base 40 .

The tundish impact pad 20 also includes a side wall 50 having a side wall inner surface 52 which continuously/uninterruptedly wraps around itself so as to appear as a ring when viewed from above, as Figure 4 shows. Sidewall 50 is shown as having a uniform thickness throughout its 360 degree extent. The sidewall inner surface 52 is positioned concentrically outboard of the annular base surface area 44 and generally perpendicular to the annular base surface area. As best shown in the cross-sectional view of FIG. 5 , sidewall inner surface 52 includes curved transition regions 54 , 56 at its bottom and top, respectively. The curved transition regions 54, 56 may be symmetrical to each other. The ends of the lower curved transition region 54 are flush with and adjoin the annular base surface region 44 and the side wall inner surface 52 . The lower curved transition region 54 is continuously curved between the base 40 and the sidewall inner surface 52 .

The tundish impact pad 20 also includes a top wall 60 extending inwardly from the top transition region 56 and generally perpendicular to the side walls 50 to terminate at an inner edge 62 . The top transition region 56 is configured as a curvilinear undercut that is continuously curved between the side wall inner surface 52 and the top wall 60 and ends flush with the side wall inner surface 52 and the top wall 60 Qi and adjoining. Mouth opening 64 formed by inner edge 62 is spaced above and centrally located relative to apex 46 . In use, the mouth opening 64 is located below and coaxially with the ladle shroud 22 to receive the incoming ladle flow 24 . In the illustrated embodiment, the diameter of the mouth opening 64 is approximately equal to or less than the diameter of the outer perimeter 48 of the tapered impact surface region 42 .

Top wall 60 includes a lip 66 that slopes inwardly and downwardly to terminate at inner edge 62 . The top wall 60 has a first lower surface region 60a extending horizontally generally parallel to the bottom surface 40a and a second lower surface region (also referred to herein as a lower lip surface) 66a, which The second lower surface area corresponds to the bottom of the lip 66 . The lower lip surface 66a slopes radially inwardly and downwardly from the first lower surface region 60a towards the tapered impact surface 42 . As best shown in Figures 4 and 5, first lower surface region 60a and lower lip surface 66a meet at 60b.

The base 40, the side walls 50 and the top wall 60 may be integral, ie a unitary part or a unitary part. Alternatively, base 40, side walls 50, top wall 60 and/or other portions of pouring tray 10 may be formed from separate components that are temporarily or permanently connected to each other. The conical impact surface area 42, the annular base surface area 44, the continuous side wall inner surface 52, the curved transition surface areas 54, 56 and the lower surface areas 60a, 66a together form a continuous annular chamber about the axis Az which may be in the form of a torus .

Referring to FIG. 7 , liquid steel is directed into the tundish 10 through a shroud or sprue 22 as an incoming ladle flow 24 . It has been found that a ratio of the diameter D _j of the inner diameter of the shroud 22 to the diameter D _m of the mouth opening 64 (D _j /D _m ) in the range of about 0.3 to about 0.4 provides particularly good results. In the exemplary embodiment, the ladle shroud 22 and the mouth opening 64 are coaxially aligned with each other. The design of the exemplary embodiments described herein is such that the incoming ladle flow 24 impinges on the conical impact surface region 42 which directs the flow 24 radially outward toward the lower transition portion 54 and sidewall inner surface 52 Reboot. The shape of the continuous annular chamber is such that the flow of molten steel is reversed towards the incoming ladle flow 24 to reduce turbulence and dissipate the energy of the molten steel before it flows from the impingement pad 10 . The reverse fluid flow exits upwardly through the mouth opening 64 and then flows generally radially outward in all directions towards the wall of the tundish 10 as a substantially laminar flow. By providing a mouth opening 64 having a larger diameter than the shroud 22 , an annular upward flow is created between the incoming ladle flow 24 and the inner edge 62 .

Molten steel exits the mouth opening 64 into the first compartment 18a. The continuous inflow of the incoming ladle flow and removal of molten steel through the outlet 34 causes the molten steel in the compartment 18a to flow towards the weir 26 and through the weir channel 26a. After passing through weir channel 28 , the molten steel flows over bank 30 and/or through cylindrical channel 30 a before exiting through outlet 34 .

The flow of molten steel reverses onto itself creating a self-braking effect. Thus, the outflow of molten steel through the mouth opening 64 and into the first compartment 18a is less turbulent and has lower energy. Thus, the above-mentioned "eye opening" and sputtering problems are significantly reduced.

In a particular exemplary embodiment designed to inhibit "eye opening," the conical impact surface region 42 has a cone angle θ( FIG. 5 ), the taper angle ranges from about 15 degrees to about 25 degrees. In another specific exemplary embodiment designed to inhibit "eye opening," the lip 66 has a downward lip angle theta(θ) measured from a horizontal plane to the plane in which the lower surface 66a of the lip 66 lies, which The angle ranges from about 20 degrees to about 25 degrees. In another specific exemplary embodiment designed to inhibit "open eyes", the continuous annular chamber has a radius of curvature of about 30mm. These exemplary embodiments may be implemented alone or with each other in any combination. The impingement chamber may have a height equal to or greater than the inner diameter of the shroud to affect flow control.

Computational fluid dynamics (CFD) simulations were performed on impact pads designed according to the above parameters. The area average velocity (a measure of flow activity on the pouring side of the top surface of the steel bath) was calculated to be about 50% lower for the embodiment embodying the invention compared to the flat petal-shaped impact pad. The likelihood of forming an "open eye" is also calculated to be reduced by the same ratio. Using CFD analysis in which velocities and areas are calculated for the number of cells and area average velocities of the mesh, the area average velocities are determined as follows:

In general, it has been found that higher areal average velocities correspond to more tundish flux entrainment and poorer quality steel, while lower areal average velocities correspond to less tundish flux entrainment and lower quality steel. High quality steel. Thus, an approximately 50% reduction in areal average velocity significantly reduces tundish flux entrainment and results in a higher quality steel product. Without being bound by theory, it is believed that the improved quality obtained with the exemplary embodiments described herein may be attributable to one or more of the following: High velocity incoming flow and reduced turbulence due to the "self-braking" effect ; less spattering during start-up and continuous operation; longer residence time of molten steel in the reservoir; facilitated flotation of impurities and particulates; and more uniform reservoir temperature.

8 and 9 illustrate an impact pad according to another exemplary embodiment. For the sake of brevity, the following description focuses on the differences between the exemplary embodiments of FIGS. 8 and 9 and the other exemplary embodiments described above. Like reference numerals indicate like or corresponding parts in the various exemplary embodiments.

In the exemplary embodiment of Figures 8 and 9, the protrusions 80 are distributed 360 degrees around the lower lip surface 66a. Protrusions 80 may be uniformly distributed, such as in a matrix pattern, or may be randomly or otherwise distributed. In the illustrated embodiment, the outer surface of the protrusion 80 has a hemispherical shape. However, protrusion 80 may take alternative shapes. Furthermore, protrusions 80 may have the same or different shapes relative to each other. It has been found that the protrusions 80 , particularly the hemispherical protrusions, further reduce the velocity of the outflow of liquid steel before exiting the impact pad 20 through the mouth opening 64 . Additionally or alternatively, protrusions 80 may be located elsewhere on the inner surface of the impact pad.

The foregoing detailed description of some exemplary embodiments has been provided in order to explain the principles of the invention and its practical application, to enable those skilled in the art to understand various embodiments of the invention and various embodiments as are suited to the particular use contemplated. Revise. This description is not necessarily intended to be exhaustive or to limit the invention to the particular embodiments disclosed. The specification describes specific examples to accomplish more general goals that could otherwise be achieved.

Only those claims using the word "intended" will be construed according to the sixth paragraph of 35USC112. Furthermore, the specification does not place any limitations on any claims unless such limitations are expressly included in the claims.

Claims (21)

1. A pouring tray impact pad, comprising: a base having a base surface including a conical impact surface area forming an apex; side walls; and a top wall extending inwardly relative to the side walls to terminate at an inner edge forming a mouth opening spaced above and centrally located relative to the apex, the top wall comprising A lip slopes radially inwardly and downwardly toward the conical impact surface. 2. The tundish impact pad of claim 1 , wherein the side walls include a continuous side wall inner surface radially outward of the base surface, and wherein the top wall includes a lower surface that is in contact with the base surface and the continuous side wall. The inner surfaces together form a continuous annular chamber configured to reduce turbulence of molten liquid steel introduced into the ladle flow. 3. The tundish impact pad of claim 2, wherein: the base surface also includes a first planar annular region between the tapered impact surface region and the continuous sidewall inner surface; the top wall includes a second planar annular region extending between the continuous side wall inner surface and the lip; and The first flat annular region and the second flat annular region are spaced apart from each other and extend in planes parallel to each other. 4. A pouring pan impact pad as claimed in any one of claims 1 to 3, wherein the conical impact surface region has an axis passing through the apex, about which axis the conical impact surface region is rotationally symmetric. 5. The tundish impact pad of claim 4, wherein the tapered impact surface region has a linear profile. 6. A tundish impact pad as claimed in claim 5, wherein the conical impact surface region has an angle measured from a horizontal plane on which the outer periphery of the conical impact surface region lies to an inclined plane on which the linear profile of the conical impact surface region lies. A cone angle ranging from about 15 degrees to about 25 degrees. 7. A tundish impact pad as claimed in any one of claims 1 to 6 wherein the lip has a downward lip angle measured from a horizontal plane to the lower surface of the lip in the range of about 20 degrees to about 25 degrees. 8. A pouring pan impact pad according to any one of claims 1 to 7, wherein the top wall includes a lower surface which, together with the base surface and the inner surface of the continuous side wall, forms a continuous annular cavity, the continuous annular cavity The radius of curvature of the chamber is approximately 30 mm. 9. A tundish impact pad according to any one of claims 1 to 8, further comprising: The protrusions are distributed around the lower surface area of the lip. 10. The tundish impact pad of claim 9, wherein the protrusion is hemispherical in shape. 11. A device comprising: a continuous caster tundish for containing a reservoir of molten metal having a fluid flow resulting from an incoming ladle flow; and A tundish impact pad according to any one of claims 1 to 10. 12. A chain casting method comprising: An incoming ladle stream of molten liquid steel is fed into a continuous casting machine tundish containing a tundish impact pad comprising a base having a base surface including a conical impact surface area forming an apex; side walls; and a top wall extending inwardly relative to the side walls to terminate at an inner edge forming a mouth opening spaced above and centrally located relative to the apex, the mouth the opening is positioned to receive the incoming ladle flow, the top wall includes a lip sloping radially inwardly and downwardly toward the conical impact surface; causing the incoming ladle flow of molten liquid steel to impact the conical impact surface area; and The molten liquid steel allowed to impinge is expelled from the tundish impingement pad through the mouth opening. 13. The chain casting method of claim 12, wherein the side walls comprise a continuous side wall inner surface radially outward of the base surface, and wherein the top wall comprises a lower surface that is in contact with the base surface and the continuous side wall The inner surfaces together form a continuous annular chamber configured to reduce turbulence of molten liquid steel introduced into the ladle flow. 14. The chain casting method of claim 13, wherein: the base surface also includes a first planar annular region between the tapered impact surface region and the continuous sidewall inner surface; the top wall includes a second planar annular region extending between the continuous side wall inner surface and the lip; and The first flat annular region and the second flat annular region are spaced apart from each other and extend in planes parallel to each other. 15. A chain casting process as claimed in any one of claims 12 to 14, wherein the conical impact surface region has an axis passing through the apex, about which axis the conical impact surface region is rotationally symmetric. 16. The chain casting method of claim 15, wherein the conical impact surface area has a linear profile. 17. Chain casting method according to claim 16, wherein the conical impact surface area has a value measured from a horizontal plane on which the outer periphery of the conical impact surface area is located to an inclined plane on which the linear profile of the conical impact surface area is located. A cone angle ranging from about 15 degrees to about 25 degrees. 18. A chain casting method according to any one of claims 12 to 17, wherein the lip has a downward lip angle measured from a horizontal plane to the lower surface of the lip, the downward lip angle is in the range of about 20 degrees to about 25 degrees. 19. A chain casting method as claimed in any one of claims 12 to 18, wherein the top wall comprises a lower surface which, together with the base surface and the inner surface of the continuous side wall, forms a continuous annular chamber, the continuous annular chamber The radius of curvature of the chamber is approximately 30 mm. 20. A chain casting method according to any one of claims 12 to 19, further comprising: The protrusions are distributed around the lower surface area of the lip. 21. The chain casting method according to claim 20, wherein the shape of the protrusion is hemispherical.