USRE29646E - Method or restoring ingot mold stools and closed-bottom ingot mold - Google Patents

Method or restoring ingot mold stools and closed-bottom ingot mold Download PDF

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Publication number
USRE29646E
USRE29646E US05/781,252 US78125277A USRE29646E US RE29646 E USRE29646 E US RE29646E US 78125277 A US78125277 A US 78125277A US RE29646 E USRE29646 E US RE29646E
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United States
Prior art keywords
cavity
mold
accordance
mixture
melt
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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.)
Expired - Lifetime
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US05/781,252
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English (en)
Inventor
Robert H. Kachik
Samuel J. Manganello
Arthur J. Pignocco
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United States Steel Corp
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United States Steel Corp
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Priority claimed from US05/664,793 external-priority patent/US4005742A/en
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Assigned to USX CORPORATION, A CORP. OF DE reassignment USX CORPORATION, A CORP. OF DE MERGER (SEE DOCUMENT FOR DETAILS). Assignors: UNITED STATES STEEL CORPORATION (MERGED INTO)
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
    • B23P6/00—Restoring or reconditioning objects
    • B23P6/04—Repairing fractures or cracked metal parts or products, e.g. castings
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D7/00—Casting ingots, e.g. from ferrous metals
    • B22D7/06—Ingot moulds or their manufacture
    • B22D7/066—Manufacturing, repairing or reinforcing ingot moulds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K23/00—Alumino-thermic welding

Definitions

  • This invention relates to a relative inexpensive method for repairing ingot molds and stools and closed-bottom ingot molds which utilize an aluminothermic reduction (ATR) bulk metal deposition process to effect such repair.
  • ATR aluminothermic reduction
  • Aluminothermic reduction (ATR) techniques have been used in the past to repair castings such as ingot molds and mold stools.
  • ATR Aluminothermic reduction
  • surface scale is usually removed from the casting and many have thought it essential to undercut the casting surface so that the deposited metal is "keyed" in, i.e. locked in place so that it will not fall out even if it is not bonded to the casting.
  • casting must be preheated in order to assure a good weld bond of the deposited metal.
  • ATR powder Since a given volume of ATR powder will yield only about a fifth as much deposited metal, by volume, it has always been necessary to use a containment perimeter to confine the ATR powder and ATR reaction products to the site to be repaired. That is to say, in order to fill a crater of given volume with a like volume of ATR deposited metal, the volume of ATR powder used must be five times greater. Hence, a refractory perimeter system is necessary to confine the ATR powder directly over the cavity to be filled. In addition, the perimeter system becomes necessary to similarly confine the molten reaction products which also have a volume greater than the cavity. That is, to yield a volume of metal equal to the volume of the cavity, an even greater volume of slag is necessarily produced.
  • the heavier metal product will settle to the bottom filling the cavity, while the slag portion accumulates at the top within the volume defined by the refractory perimeter system.
  • the perimeter system and overlaying slag are removed, leaving the deposited metal in the cavity.
  • This invention concerns a method for repairing large castings, such as ingot molds and stools, particularly a method of filling erosion craters therein, which employs an exothermic reduction reaction, such as an aluminothermic reduction reaction and which does not require the above described complicated procedures.
  • This method does not require any surface conditioning, any preheating nor the use of a perimeter system.
  • the chemical reaction can be represented as:
  • MeO represents the oxide of the metal to be deposited, such as hematite (Fe 2 O 3 )
  • Al is the aluminum fuel
  • Al 2 O 3 the oxide of aluminum, which is a major constituent of the resulting slag.
  • One novel and critical step in our method is the proper disposition of the ATR charge when the ATR reaction is initiated.
  • the ATR charge consisting of a stoichiometric mixture of aluminum and iron oxide, is placed within the defective area such as an erosion pit, etc. Since the reaction takes place and the superheated metal is generated in intimate contact with the substrate surface instead of in a crucible as is normally practiced, the heat of reaction is efficiently utilized, thereby enhancing the bonding of the deposited metal to the steel substrate.
  • FIG. 1 is a transverse cross-section of an eroded mold stool and the necessary material to accomplish our method.
  • FIG. 2 is a transverse cross-section of a mold stool repaired by the invented method.
  • FIG. 3 is a transverse cross-section of a big-end-up (BEU) ingot mold set-up according to another embodiment of our method of depositing an abrasion-resistant monolithic ceramic liner in the bottom thereof.
  • BEU big-end-up
  • FIG. 4 is a transverse cross-section of the ingot mold of FIG. 3 after deposition of a ceramic bottom liner.
  • a mold stool 10 has been eroded in service to such an extent that a crater 12 exists in the surface of the stool.
  • the mixture 14 is deposited in an amount sufficient to overfill the crater 12 so that a mound 16 of mixture 14 is formed. Ideally, about a 50% excess of mixture 14 is desired. As shown, the 50% excess is domed over the crater 12.
  • the mixture 14 is preferably an aluminothermic reduction (ATR) reaction mixture.
  • the mixture consists of about three parts powdered iron oxide, which is preferably Fe 2 O 3 and not finer than +200 mesh, and preferably having a size at least as fine as -35 mesh, one part aluminum powder preferably having a size between about -100 mesh and +400 mesh.
  • Other fuels that might be used instead of aluminum are magnesium, calcium, silicon and calcium-silicon alloy or mixtures thereof.
  • the ATR mixture 14 is ignited by a flame, flare or hot filament. The reaction causes the formation of a superheated melt comprising a metal phase 20 (FIG. 2) and a slag phase 22. The more dense metal phase quickly separates from the melt and settles to the bottom where it becomes metallurgically bonded to the stool.
  • any oxide scale which may have existed on the surface of the mold stool is either chemically reduced or melted with the overlaying slag phase 22. It is believed that this "in situ" bulk deposition process uses the heat of reaction efficiently to provide a mechanism for cleaning and descaling the surface, thereby enhancing the formation of additional filler material which becomes welded to the stool.
  • a metal phase 20 has been weld bonded to the stool 10.
  • the overlaying slag phase 22 is firmly attached to the metal phase 20 therebeneath, and is left in place to provide additional, although temporary, protection from erosion.
  • ATR mixture Since a considerably greater amount of deposited metal was necessary, a correspondingly greater amount of ATR mixture was necessary. As noted above, this then necessitated building or placing a refractory containment perimeter system around the cavity to contain the extra ATR mixture and reaction products so that the metal would enter the cavity. In practice, it was found necessary that the loose ATR mixture have a volume of approximately six times greater than the volume of the cavity. In the above practice, however, wherein both reaction products are to fill the cavity, i.e. the metal and slag phases, the ATR mixture should have a volume of one and a half times that of the crater in order to fill the crater. Accordingly, a refractory perimeter system is not necessary, and hence the repair can be effected without the need of any apparatus whatsoever.
  • the loose ATR mixture provided should have a volume about 50% greater than the volume of the cavity. It should be noted, however, that it is not necessary that the metal and slag phases completely fill the cavity. Indeed, the upper surface of the slag phase 22 may be lower than the upper surface of the mold stool 10 without sacrificing any advantages. In some applications, it may even be desirable that the cavity be under-filled as the slag phase 22 tends to "lock" in place into the cavity walls. In addition to the above modifications, it is not necessary that all of the ATR mixture be applied in the cavity at one time.
  • the cavity can be partially filled with ATR mixture, the mixture reacted, and then subsequently more ATR mixture may be added and then reacting that the mixture.
  • ATR mixture the reaction products from the first added ATR mixture are still molten when the second ATR mixture is added, the two metal phases and the two slag phases will combine to yield just two phases substantially as shown in FIG. 2.
  • the reaction products from the first added ATR mixture have solidified when the second ATR mixture is added, four distinct layers will be formed, i.e. metal and overlaying slag from the first ATR mixture and then second metal and slag layers thereover from the second ATR mixture.
  • the above described procedure for adding the ATR mixture at two different times does provide one advantage in that upper slag layer formed when the second ATR mixture is reacted tends to be more dense, i.e. less porous. It is believed that the first ATR reaction results in some slag porosity because the reaction is in contact with the cast iron mold stool, and carbon in the cast iron reacts with oxygen in the ATR mixture to form some CO 2 . However, the second ATR products are exposed to substantially less cast iron surface, and hence less CO 2 is formed. It is interesting to note that this greater slag density results whether or not the first ATR reaction products have solidified when the second ATR mixture is added.
  • FIGS. 3 and 4 illustrate this embodiment wherein a closed-bottom ingot mold 30, having an erosion cavity 32 in the bottom thereof is repaired.
  • sufficient ATR mixture 34 is provided to cover the bottom of the mold to a depth no greater than about three inches as sufficient to assure that the ATR reaction slag phase 36 not only fills the upper portion of cavity 32 but also forms a thin layer of slag completely covering the bottom of mold 30.
  • the metal phase 36 will be securely bonded to the bottom of the cavity 32, while the slag phase 38 will be attached to the metal phase 36 and the bottom of the ingot mold 30.
  • the slag phase layer should not be more than about one or two inches thick, since thicker deposits may result in shorter ingots stripped therefrom, unless of course, special overly tall ingot molds are involved.
  • the metal phase 36 covers the entire bottom of the ingot mold 30 problems may be encountered. Specifically if the metal layer is thick, the slag layer will be even thicker and hence the depth of the mold will be appreciably reduced. This will result in appreciably shorter ingot cast therein. On the other hand, if such a metal phase layer is thin, the heat therein is quickly dissipated to the mold bottom, and hence the metal does not form a good bond with the mold bottom. For optimum results therefore, the amount of ATR mixture used in this embodiment should be such that the entire metal phase is contained within the cavity so that only the slag phase extends from mold wall to wall.
  • volume of ATR mixture used should be more than 1.5 times the volume of the cavity, i.e. that amount necessary to fill only the cavity with metal and slag; and should be less than 5 times the volume of the cavity, i.e. that amount which would completely fill the cavity with metal phase.
  • the slag deposit not cause ingot contamination, but it does provide the beneficial result of being less susceptible to melt away erosion during teeming.
  • the slag phase does provide extra protection from erosion and does extend the life of the repaired stool or mold.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Furnace Housings, Linings, Walls, And Ceilings (AREA)
  • Molds, Cores, And Manufacturing Methods Thereof (AREA)
  • Continuous Casting (AREA)
  • Polishing Bodies And Polishing Tools (AREA)
  • Photoreceptors In Electrophotography (AREA)
US05/781,252 1976-03-08 1977-03-25 Method or restoring ingot mold stools and closed-bottom ingot mold Expired - Lifetime USRE29646E (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US05/664,793 US4005742A (en) 1974-10-25 1976-03-08 Method of restoring ingot mold stools and closed-bottom ingot mold

Related Parent Applications (2)

Application Number Title Priority Date Filing Date
US51799174A Continuation-In-Part 1974-10-25 1974-10-25
US05/664,793 Reissue US4005742A (en) 1974-10-25 1976-03-08 Method of restoring ingot mold stools and closed-bottom ingot mold

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USRE29646E true USRE29646E (en) 1978-05-30

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US (1) USRE29646E (xx)
AR (1) AR215881A1 (xx)
AT (1) AT352309B (xx)
AU (1) AU503783B2 (xx)
BR (1) BR7701333A (xx)
DE (1) DE2705834A1 (xx)
ES (1) ES456590A1 (xx)
FR (1) FR2343539A1 (xx)
GB (1) GB1571661A (xx)
IN (1) IN147462B (xx)
IT (1) IT1082471B (xx)
MX (1) MX144530A (xx)
NO (1) NO770780L (xx)
SE (1) SE432728B (xx)
ZA (1) ZA77653B (xx)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040093984A1 (en) * 2002-11-14 2004-05-20 Kachik Robert Henry Aluminothermic reduction mixtures

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2787925B1 (fr) 1998-12-24 2001-03-09 Cit Alcatel Generateur electrochimique dans lequel une electrode a un bord renforce par un feuillard
CN113601103B (zh) * 2021-06-25 2022-10-14 上海航天精密机械研究所 一种铝、镁合金铸件疏松缺陷修复方法

Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3264696A (en) * 1962-06-13 1966-08-09 Charles F Funk Method of cladding metal surfaces
US3340082A (en) * 1962-11-19 1967-09-05 Prochirhin Sa Process of extending the duration of service of ingot molds
US3357481A (en) * 1965-08-27 1967-12-12 Nalco Chemical Co Method of inhibiting erosion on mold surfaces
US3396776A (en) * 1965-10-20 1968-08-13 Jennings B Thompson Method of cladding metal
US3421570A (en) * 1967-02-20 1969-01-14 Elektro Thermit Gmbh Aluminothermic welding process
FR1587253A (xx) * 1968-10-28 1970-03-13
DE2014608A1 (en) * 1967-08-21 1970-10-15 VEB Chemische Werke Buna, Schkopau Alumina thermal repair of cast iron articles
US3540514A (en) * 1966-05-09 1970-11-17 Foseco Int Production of metal ingots,slabs and billets
US3674518A (en) * 1970-01-19 1972-07-04 Toseco Intern Ltd Refractory dressing method
US3856076A (en) * 1973-02-15 1974-12-24 United States Steel Corp Apparatus for containing the molten reaction products of a reactive cladding process
US3942578A (en) * 1973-02-15 1976-03-09 United States Steel Corporation Method of repairing large castings
US3946793A (en) * 1973-02-15 1976-03-30 United States Steel Corporation Method of forming a high-temperature abrasion-resistant coating on a ferrous metal substrate

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1436561A (en) * 1973-01-18 1976-05-19 Foseco Int Repair of ingot mould bottom plates
US3933191A (en) * 1973-02-15 1976-01-20 United States Steel Corporation Method for containing the molten reaction products of a reactive cladding process
DE2450043C2 (de) * 1973-10-24 1984-12-06 Goricon Metallurgical Services Ltd., Bridgend, Glamorgan Verfahren zum Füllen eines Loches in einem Körper aus eisenhaltigem Metall
US4005742A (en) * 1974-10-25 1977-02-01 United States Steel Corporation Method of restoring ingot mold stools and closed-bottom ingot mold
FR2326260A1 (fr) * 1975-10-02 1977-04-29 Uss Eng & Consult Procede de reparation de grandes pieces moulees

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3264696A (en) * 1962-06-13 1966-08-09 Charles F Funk Method of cladding metal surfaces
US3340082A (en) * 1962-11-19 1967-09-05 Prochirhin Sa Process of extending the duration of service of ingot molds
US3357481A (en) * 1965-08-27 1967-12-12 Nalco Chemical Co Method of inhibiting erosion on mold surfaces
US3396776A (en) * 1965-10-20 1968-08-13 Jennings B Thompson Method of cladding metal
US3540514A (en) * 1966-05-09 1970-11-17 Foseco Int Production of metal ingots,slabs and billets
US3421570A (en) * 1967-02-20 1969-01-14 Elektro Thermit Gmbh Aluminothermic welding process
DE2014608A1 (en) * 1967-08-21 1970-10-15 VEB Chemische Werke Buna, Schkopau Alumina thermal repair of cast iron articles
FR1587253A (xx) * 1968-10-28 1970-03-13
US3674518A (en) * 1970-01-19 1972-07-04 Toseco Intern Ltd Refractory dressing method
US3856076A (en) * 1973-02-15 1974-12-24 United States Steel Corp Apparatus for containing the molten reaction products of a reactive cladding process
US3942578A (en) * 1973-02-15 1976-03-09 United States Steel Corporation Method of repairing large castings
US3946793A (en) * 1973-02-15 1976-03-30 United States Steel Corporation Method of forming a high-temperature abrasion-resistant coating on a ferrous metal substrate

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040093984A1 (en) * 2002-11-14 2004-05-20 Kachik Robert Henry Aluminothermic reduction mixtures

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FR2343539B1 (xx) 1982-04-02
SE432728B (sv) 1984-04-16
AR215881A1 (es) 1979-11-15
AU503783B2 (en) 1979-09-20
IT1082471B (it) 1985-05-21
AU2199377A (en) 1978-08-17
MX144530A (es) 1981-10-23
ES456590A1 (es) 1978-02-16
NO770780L (no) 1977-09-09
IN147462B (xx) 1980-03-08
DE2705834A1 (de) 1977-09-15
GB1571661A (en) 1980-07-16
ATA148477A (de) 1979-02-15
SE7702258L (sv) 1977-09-09
FR2343539A1 (fr) 1977-10-07
BR7701333A (pt) 1977-12-20
AT352309B (de) 1979-09-10
ZA77653B (en) 1977-12-28

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Owner name: USX CORPORATION, A CORP. OF DE, STATELESS

Free format text: MERGER;ASSIGNOR:UNITED STATES STEEL CORPORATION (MERGED INTO);REEL/FRAME:005060/0960

Effective date: 19880112