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

Definitions

• This invention relates to a tundish impact pad, i.e. a pad of erosion resistant material positioned on the floor of a tundish to receive the incoming stream of molten metal poured into the tundish from a ladle.
• U.S. patent 5169591 discloses an impact pad for a tundi h for continuous casting of steel that comprises a base, a peripheral top surface and a discontinuous sidewall extending between the base and the peripheral top surface, the sidewall having an undercut inner surface, which may be curvilinear.
• U.S. patent 5358551 discloses an impact pad which comprises a base, a sidewall extending around the base, the sidewall having an inner surface having a portion which extends inwardly and upwardly. That inner surface may be concave.
• both of the aforesaid types of impact pad are designed to reduce turbulence in the tundish
• improved turbulence reduction can be achieved by providing an impact pad with internal corners defined between its base, its peripheral wall and its upper surface.
• the invention provides a tundish impact pad comprising a body of refractory material capable of withstanding contact with molten steel in a tundish; the body comprising a base having an impact surface, an endless outer sidewall extending upwardly from the impact surface, a top surface connected to the sidewall and defining an opening therein, the top surface having an inner annular portion substantially parallel to the impact surface and the sidewall having an interior face which is substantially perpendicular to the impact surface and wherein a substantially right angle corner is provided between the sidewall and the impact surface and a substantially right angle corner is provided between the sidewall and the top surface inner annular portion.
• Molten steel entering through the opening and contacting the impact surface flows outwardly then is turned inwardly by the sidewall interior face and then flows out the opening.
• the sidewall is endless, i.e. it extends continuously around the impact surface.
• the opening is non-uniform in that it has a long dimension and a short dimension perpendicular to the long dimension.
• the opening may be, for example, rectangular or oval.
• the top outer surface of the pad may conveniently also be parallel to the impact surface.
• the impact pads of the present invention uniformly disperse the flow of incoming steel rather than merely redirecting it. Since the steel flow can be dispersed over a larger area than if a circular or other uniform configuration were used, the result is more uniformly surface directed flow while maintaining the benefits of reduced splash and turbulence. Also due to the non-uniform configuration of the impact pad it presents a larger • "target" to the incoming steel than a similar width uniform shaped pad (e.g. circular or square), with the desired results obtained even if the steel stream is imperfectly aligned with the centre of the impact pad.
• a similar width uniform shaped pad e.g. circular or square
• the invention is particularly useful in providing improved residence time distribution parameters in the poured molten steel. It can also be of reduced cost due to its simplified internal chamber shapes and may be of reduced overall size relative to known impact pads.
• the impact pads according to the present invention are formed of a refractory composition which is capable of withstanding continuous contact with molten metal, in particular, molten steel such as used in continuous casting operations.
• molten metal in particular, molten steel
• a standard medium- to-high alumina monolithic refractory with an alumina content in the range of about 55 to 85% by weight is desirable.
• a basic refractory is preferred because of steel chemistry, it is preferred that a magnesia based monolithic refractory be utilised, with MgO in the range of about 58 to 93% by weight.
• the invention provides a tundish for holding a volume of molten steel and having a floor and side walls enclosing a region of impact and a drain, an impact pad of the present invention being provided on the floor of the tundish in the region of impact.
• Figure 1 is a side cross-sectional view of a tundish including an impact pad of the invention disposed on the floor of the tundish;
• Figure 2 is a top plan view of the impact pad of Figure 1, which illustrates where the cross-section of Figure 1 is taken (along line I to I);
• Figure 3 is a cross- section along line III to III of Figure 2.
• Figure 4 is an enlarged sectional view of a portion of the impact pad of Figure 3.
• a conventional tundish 10 is shown and includes an inner lining 12 and a pair of well blocks or outlets 14 to allow molten metal (typically steel) from a bath 16 contained in the tundish 10 to continuously exit the tundish 10 and enter moulds (not shown) which form metal castings.
• a ladle shroud 18 or like tundish filling device is positioned above the tundish 10 and continuously directs a stream of molten metal into the tundish 10.
• a tundish impact pad 20 constructed according to the present invention is placed generally centrally on the floor 15 of the tundish 10.
• the tundish impact pad 20 is preferably rectangular in shape and is positioned with its longer sides parallel to the longitudinal axis of the tundish.
• the pad includes a base - 5 -
• the pad 20 further includes an endless, annular outer sidewall 26, 40 having an inner wall face surface 28.
• the impact pad 20 also has a top surface 32 parallel to the impact surface 24 and connected to the sidewall 26, 40 and defining a non-uniform opening 30 therein.
• non-uniform it is meant that the opening 30 is not circular or square; rather it has a long dimension 30' (see Figure 2) and a short dimension 30" substantially perpendicular to the long dimension 30'.
• the interior face 28 of the sidewall extends upwardly substantially at right angles to the impact surface 24 around the entire periphery thereof.
• the continuous nature of the inner surface 28 is perhaps seen most clearly in Figure 2, being shown in dotted line therein.
• the sidewall 28, with impact surface 24 and underside portion 42 of top surface 32 provides two sharp corners 28A and 28B respectively, which corners also extend continuously around the inside of the impact pad.
• the outer sidewall 26 may be tapered inwardly from the top surface 32 toward the base 22, defining ears 27 at opposite ends.
• the ears 27 facilitate connection of the impact pad 20 to the base or floor 15 of the tundish when certain types of tundishes are utilised.
• the impact pad 20 may merely be mounted in a conventional manner on the bottom of the tundish.
• the bottom portion of the top surface 32 has annular portions 39, 42 (see Figure 3) thereof, which lie parallel to the impact surface 24.
• This annular, overhang surface 42 facilitates proper directing of the molten steel during filling of the tundish 10.
• the long dimension 30' of the opening 30 is positioned aligned with the long dimension of the tundish (the dimension between the outlets 14, as seen in Figure 1), whereas the short dimension 30" of the opening 30 is aligned with the short dimension of the tundish 10.
• outer sidewall portions 40 rather than being tapered inwardly like the sidewall portions 26, preferably taper very slightly (e.g. 2 to 5°) outwardly, as seen in Figure 3.
• straight sides may be provided for both walls 26, 40 and straight sidewalls 26 may or may not contain ears 27.
• the refractory material of which the impact pad 20 is made must be capable of withstanding continuous contact with molten steel during the entire use cycle of the tundish 10. It must have adequate refractoriness normally available from a standard medium-to-high alumina monolithic refractory. For example, an alumina content in the range of about 55 to 85% may be utilised. Where a basic refractory is preferred because of the steel chemistry, typically an MgO-based monolithic refractory, with MgO in the range of about 58 to 93% is preferred.
• the impact pad 20 be rectangular in shape, as illustrated in Figures 1 through 4, other non-uniform configurations can also be provided.
• an oval impact pad may be utilised, or another type of multi-sided polygon configuration, as long as there is an opening with a long dimension which is aligned with the long dimension of the tundish 10 and a short dimension aligned with the short dimension of the tundish 10.
• molten steel flowing in the path 34 from a location disposed above the pad 20 strikes the impact surface 24 and then moves radially outwardly as illustrated by arrows 35.
• small corner fillets may be present in the right- angle corners between the sidewall and the impact surface and /or the top surface inner annular portion.

Landscapes

• Mechanical Engineering (AREA)
• Engineering & Computer Science (AREA)
• Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
• Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
• Excavating Of Shafts Or Tunnels (AREA)
• Silicon Polymers (AREA)
• Vehicle Step Arrangements And Article Storage (AREA)
• Cold Cathode And The Manufacture (AREA)
• Fluid-Damping Devices (AREA)
• Laminated Bodies (AREA)
• Ceramic Products (AREA)
• Refuge Islands, Traffic Blockers, Or Guard Fence (AREA)
• Details Of Garments (AREA)
• Professional, Industrial, Or Sporting Protective Garments (AREA)
• Ultra Sonic Daignosis Equipment (AREA)
• Feeding, Discharge, Calcimining, Fusing, And Gas-Generation Devices (AREA)
• Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
• Molds, Cores, And Manufacturing Methods Thereof (AREA)

Applications Claiming Priority (5)

Publications (2)

Family

ID=26306906

Family Applications (1)

Country Status (14)

Families Citing this family (16)

Family Cites Families (4)

• 1995
  • 1995-10-24 BR BR9509706A patent/BR9509706A/pt active IP Right Grant
  • 1995-10-24 DE DE69502838T patent/DE69502838T2/de not_active Expired - Lifetime
  • 1995-10-24 JP JP51581096A patent/JP4007429B2/ja not_active Expired - Lifetime
  • 1995-10-24 ES ES95934731T patent/ES2104525T3/es not_active Expired - Lifetime
  • 1995-10-24 EP EP95934731A patent/EP0790873B1/de not_active Expired - Lifetime
  • 1995-10-24 WO PCT/GB1995/002505 patent/WO1996014951A1/en active IP Right Grant
  • 1995-10-24 CN CN95197120A patent/CN1069243C/zh not_active Expired - Lifetime
  • 1995-10-24 AT AT95934731T patent/ATE166814T1/de active
  • 1995-10-24 AU AU37043/95A patent/AU692622B2/en not_active Expired
  • 1995-10-24 DK DK95934731T patent/DK0790873T3/da active
  • 1995-11-08 TR TR95/01393A patent/TR199501393A2/xx unknown
  • 1995-11-09 CA CA002162551A patent/CA2162551C/en not_active Expired - Lifetime
  • 1995-11-28 TW TW084112638A patent/TW321615B/zh not_active IP Right Cessation
• 1997
  • 1997-05-07 FI FI971968A patent/FI110312B/fi not_active IP Right Cessation

Non-Patent Citations (1)

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