US3802482A - Process for making directionally solidified castings - Google Patents

Process for making directionally solidified castings Download PDF

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Publication number
US3802482A
US3802482A US00233168A US23316872A US3802482A US 3802482 A US3802482 A US 3802482A US 00233168 A US00233168 A US 00233168A US 23316872 A US23316872 A US 23316872A US 3802482 A US3802482 A US 3802482A
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US
United States
Prior art keywords
mold
alloy
coating
core
casting
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.)
Expired - Lifetime
Application number
US00233168A
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English (en)
Inventor
C Phipps
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Raytheon Technologies Corp
Original Assignee
United Aircraft Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by United Aircraft Corp filed Critical United Aircraft Corp
Priority to US00233168A priority Critical patent/US3802482A/en
Priority to CA154,862A priority patent/CA981416A/en
Priority to IL41118A priority patent/IL41118A/en
Priority to GB5845672A priority patent/GB1405768A/en
Priority to SE7216591A priority patent/SE403058B/xx
Priority to AU50273/72A priority patent/AU466583B2/en
Priority to DE2303181A priority patent/DE2303181A1/de
Priority to FR7306389A priority patent/FR2174858B1/fr
Priority to BE128155A priority patent/BE796024A/xx
Priority to IT21316/73A priority patent/IT983513B/it
Priority to CH349573A priority patent/CH585077A5/xx
Application granted granted Critical
Publication of US3802482A publication Critical patent/US3802482A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B21/00—Unidirectional solidification of eutectic materials
    • C30B21/02—Unidirectional solidification of eutectic materials by normal casting or gradient freezing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C3/00—Selection of compositions for coating the surfaces of moulds, cores, or patterns
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D27/00—Treating the metal in the mould while it is molten or ductile ; Pressure or vacuum casting
    • B22D27/04—Influencing the temperature of the metal, e.g. by heating or cooling the mould
    • B22D27/045—Directionally solidified castings
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
    • C23C4/04—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the coating material
    • C23C4/10—Oxides, borides, carbides, nitrides or silicides; Mixtures thereof
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
    • C23C4/04—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the coating material
    • C23C4/10—Oxides, borides, carbides, nitrides or silicides; Mixtures thereof
    • C23C4/11—Oxides
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T50/00—Aeronautics or air transport
    • Y02T50/60—Efficient propulsion technologies, e.g. for aircraft

Definitions

  • the present invention relates to a process for making directionally solidified castings and is applicable to the well known superalloys having nickel or cobalt base and also to titanium base alloys, eutectics and quasieutectics and other alloys having one or more ingredients that react with the mold or core material.
  • One feature of the invention is the coating of the surface of the mold or core which is in contact with the molten alloy with a material which will minimize interaction between the alloy and the mold or core.
  • Another feature is the coating of the exposed parts of the mold or core with an oxide of one of the reactive elements in the alloy for the purpose of minimizing reactions between the alloy and thematerial of the core or mold.
  • the process involves forming the mold which is generally a shell type mold, coating the surface of the mold that is exposed to the alloy with a material with which the reactive element of the alloy does not react, filling themold with the alloy and causing solidification of the alloy in the mold.
  • the invention contemplates making a split mold so that the coating may be readily applied to the inner surface of the mold which contacts with the alloy when the mold is filled with the molten alloy in making the cast- BRIEF DESCRIPTION 'OF THE DRAWING
  • FIG. 1 is a vertical sectional view through a mold for a turbine blade showing a core in position.
  • FIG. 2 is a horizontal sectional view through the mold of FIG. 1
  • the mold and/or core are generally made of a ceramic material such as silica, alumina, zircon or a combination of these compounds with the silica serving as a high temperature bond tohold the particles together.
  • the inner surface of the mold may also be a finer material than the rest of the mold in order to give a smooth surface finish to the wall of the casting cavity. This surface is formed by the first dip coat used in preparing the multi-layer mold in shell molding and is generally of the same material as the rest of the mold, that is to say, silica, alumina, zircon and/or a combination of these compounds but in which the particles are more finely powdered to give the smoother surface.
  • the term mold will hereinafter be used to include the core which is essentially a part of the mold.
  • the mold surface a coating of an oxide which will be inert to the reactant ingredient of the alloy. In most cases, this coating will be the oxide of the refractory ingredient in the alloy. Thus, if the alloy has hafnium as an addition, the applied coating would be hafnia since this is an inert oxide. If the alloy being cast is an yttrium bearing alloy, the core and the mold would have a coating of yttria.
  • the inert oxide used for coating the mold would desirably be the most inert oxide available and useable and thus would'be yttria or hafnia.
  • zirconia was found to be sufficiently inert to provide a retarded reaction between the mold and the alloy so that compositionally good surfaces of the casting were obtained.
  • the oxide coating may be applied in a number of different ways but is preferably applied by either flame spraying or plasma spraying of the oxide onto the surface of the mold. Under most circumstances the mold was at room temperature at the start of the spraying operation. More uniform coatings were found to be possible under certain circumstances if the mold were warmed somewhat, for example, to a temperature of about 600F.
  • the core presents no problem in being coated either by flame or plasma spraying or by other suitable means prior to positioning in the mold, or in the pattern around which the mold is formed.
  • the mold may be difficult to coat unless the mold is split or made in several parts to expose the alloy contacting surfaces when the mold is open.
  • the mold is made up of two opposed and cooperating parts 2 and 4 which are separableone from another and are so made during the mold forming process by positioning separators 6, for example, at leading and trailing edges of the airfoil portion 8 of the mold.
  • separators extend upwardly for the entire length of the mold so that the latter may be separated in two pieces and thereby expose the inner surface of the mold, the part that contacts with the alloy during the casting operation so that a spray coating operation may readily be performed thereon.
  • the separators will obviously be so made that the material of the mold will not adhere thereto and thereby permit easy separation of the mold into the two parts.
  • the split is so arranged that if there is a core 10 positioned in the mold, the core may be positioned along the line of separation of the mold for support by the mold. In making the casting the mold is positioned on a chill plate 12.
  • the effect of the sprayed-on coating is to so completely cover the surface of the mold coming in contact with the alloy being cast that the reactive elements in the mold will not be exposed directly to the alloy itself. It is believed that the greatest reaction between the alloy and the mold occurs with the silica in the mold and the coating effectively insulates the silica within the mold from the alloy when it is poured into the mold.
  • the coating of the mold or core is of particular advantage where the solidification time is relatively long as in the solidification of some of the eutectic alloys or the nickel or cobalt base alloys which are solidified in a directionally solidified arrangement thereby producing either the columnar grain of the VerSnyder patent above referred to, the single crystal of the Piearcey patent or the so-called plane front solidification.
  • a high purity alumina coating was applied to a zircon-silica core for use with a cobalt base alloy PWA 657 having the following composition:
  • a similar alloy UARL 236C was used with the same type of alumina coated core and again the effect of the coating was to minimize the surface carbon depletion in the cast alloy.
  • the composition of this alloy is as follows:
  • the titanium alloy used was a cast alloy similar to AMS 4928 (6A1, 4V, Bal Ti).
  • Another alloy PWA-AMRDL 350 having the following composition incorporates yttrium as a modifying ingredient:
  • Nickel Balance To minimize the depletion of yttrium from the alloy, the split mold was plasma sprayed with yttria prior to the casting operation. The effect was almost completely to reduce the reaction between the mold and the alloy so that depletion of yttrium in the alloy was eliminated to the extent that could be determinedfrom testing the various portions of the cast alloy. This alloy was directionally solidified to produce columnar grained structure.
  • An alloy to which hafnium has been added as a modifying ingredient PWA 1422 has the following composition:
  • Nickel Remainder This alloy was cast in a mold the surface of which was coated with hafnia by a plasma spray coating process. This alloy was directionally solidified to produce a single crystal structure in the cast alloy. The use of the hafnia coating reduced the hafnium losses through reaction with the mold significantly.
  • this leachant is preferably either a solution of NaOH or KOH in water. The same leachant has been used on the eutectics and core removal was not detrimentally affected.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Coating By Spraying Or Casting (AREA)
  • Mold Materials And Core Materials (AREA)
US00233168A 1972-03-09 1972-03-09 Process for making directionally solidified castings Expired - Lifetime US3802482A (en)

Priority Applications (11)

Application Number Priority Date Filing Date Title
US00233168A US3802482A (en) 1972-03-09 1972-03-09 Process for making directionally solidified castings
CA154,862A CA981416A (en) 1972-03-09 1972-10-25 Process for making directionally solidified castings
GB5845672A GB1405768A (en) 1972-03-09 1972-12-19 Casting processes employing coated moulds
SE7216591A SE403058B (sv) 1972-03-09 1972-12-19 Forfarande for att gjuta produkter av nickel-, kobolt- eller titanbaserade legeringar, vilka innefattar minst ett emne som omsettes med materialet i formen vid gjutningen, varvid formen belegges med en inert oxid
AU50273/72A AU466583B2 (en) 1972-03-09 1972-12-19 Process for making directionally solidified castings
IL41118A IL41118A (en) 1972-03-09 1972-12-19 A process for making directionally solidified castings from alloys that contain a single element that reacts with the pattern
DE2303181A DE2303181A1 (de) 1972-03-09 1973-01-23 Giessverfahren
FR7306389A FR2174858B1 (ru) 1972-03-09 1973-02-14
BE128155A BE796024A (fr) 1972-03-09 1973-02-27 Procede de preparation de pieces coulees solidifiees directionnellement
IT21316/73A IT983513B (it) 1972-03-09 1973-03-08 Procedimento per la fabbricazione di pezzi fusi solidificati dire zionalmente
CH349573A CH585077A5 (ru) 1972-03-09 1973-03-09

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US00233168A US3802482A (en) 1972-03-09 1972-03-09 Process for making directionally solidified castings

Publications (1)

Publication Number Publication Date
US3802482A true US3802482A (en) 1974-04-09

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ID=22876166

Family Applications (1)

Application Number Title Priority Date Filing Date
US00233168A Expired - Lifetime US3802482A (en) 1972-03-09 1972-03-09 Process for making directionally solidified castings

Country Status (11)

Country Link
US (1) US3802482A (ru)
AU (1) AU466583B2 (ru)
BE (1) BE796024A (ru)
CA (1) CA981416A (ru)
CH (1) CH585077A5 (ru)
DE (1) DE2303181A1 (ru)
FR (1) FR2174858B1 (ru)
GB (1) GB1405768A (ru)
IL (1) IL41118A (ru)
IT (1) IT983513B (ru)
SE (1) SE403058B (ru)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3888301A (en) * 1974-06-07 1975-06-10 United Aircraft Corp Multi-part mold clamp
US3908733A (en) * 1973-10-26 1975-09-30 United Technologies Corp Method and apparatus for control of alloy in columnar grain castings
US3927710A (en) * 1974-08-21 1975-12-23 United Technologies Corp Joining of multi-section ceramic molds
US3972367A (en) * 1975-06-11 1976-08-03 General Electric Company Process for forming a barrier layer on ceramic molds suitable for use for high temperature eutectic superalloy casting
US3973750A (en) * 1972-10-06 1976-08-10 Office National D'etudes Et De Recherches Aerospatiales (O.N.E.R.A.) Casting mold for directional solidification of an alloy
US4031945A (en) * 1976-04-07 1977-06-28 General Electric Company Process for making ceramic molds having a metal oxide barrier for casting and directional solidification of superalloys
US4147201A (en) * 1975-02-20 1979-04-03 Office National D'etudes Et De Recherches Aerospatiales (O.N.E.R.A.) Method of manufacturing of a metallurgical mold
US5337800A (en) * 1992-09-09 1994-08-16 Cook Arnold J Reactive coating
US20040176715A1 (en) * 2003-03-04 2004-09-09 Nelson Ronald E. Self adjusting knee brace
US20040232582A1 (en) * 2001-04-17 2004-11-25 Fts Systems, Llc (A/K/A Fts, Llc) Method and apparatus with redundancies, for treating substrate plastic parts to accept paint without using adhesion promoters
US20050045301A1 (en) * 2003-08-28 2005-03-03 Bullied Steven J. Investment casting
CN106363131A (zh) * 2016-09-21 2017-02-01 上海万泽精密铸造有限公司 钛合金铸造用陶瓷型壳面层改性的方法
WO2022157331A1 (en) * 2021-01-22 2022-07-28 Oerlikon Metco Ag, Wohlen Transplanted thermal barrier coating system

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2124116A (en) * 1982-07-09 1984-02-15 Rolls Royce A coating on a foundry core or mould
US6494250B1 (en) * 2001-05-14 2002-12-17 Howmet Research Corporation Impregnated alumina-based core and method
CN111621731B (zh) * 2020-06-11 2022-09-30 南昌硬质合金有限责任公司 一种硬质合金烧结用石墨舟皿隔离涂层的制备方法

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3180632A (en) * 1961-10-02 1965-04-27 North American Aviation Inc Coated crucible and crucible and mold coating method
US3373795A (en) * 1965-08-10 1968-03-19 Trw Inc Gating of unshrouded airfoils to permit directional solidification
US3472310A (en) * 1967-04-26 1969-10-14 Ford Motor Co Shell mold and process for shell molding
US3515201A (en) * 1967-11-14 1970-06-02 Amsted Ind Inc Method of casting
GB1234575A (ru) * 1966-10-24 1971-06-03
US3645767A (en) * 1969-02-19 1972-02-29 Monsanto Chemicals Process for coating ceramic molds
US3727666A (en) * 1971-08-16 1973-04-17 Howmet Corp Method of casting using a mold having a refractory coating thereon
US3743003A (en) * 1971-06-03 1973-07-03 Rem Metals Corp Making investment shell molds inhibited against reaction with molten reactive and refractory casting metals

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2857285A (en) * 1954-08-16 1958-10-21 Stephen D Stoddard High temperature refractory coating for graphite molds

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3180632A (en) * 1961-10-02 1965-04-27 North American Aviation Inc Coated crucible and crucible and mold coating method
US3373795A (en) * 1965-08-10 1968-03-19 Trw Inc Gating of unshrouded airfoils to permit directional solidification
GB1234575A (ru) * 1966-10-24 1971-06-03
US3472310A (en) * 1967-04-26 1969-10-14 Ford Motor Co Shell mold and process for shell molding
US3515201A (en) * 1967-11-14 1970-06-02 Amsted Ind Inc Method of casting
US3645767A (en) * 1969-02-19 1972-02-29 Monsanto Chemicals Process for coating ceramic molds
US3743003A (en) * 1971-06-03 1973-07-03 Rem Metals Corp Making investment shell molds inhibited against reaction with molten reactive and refractory casting metals
US3727666A (en) * 1971-08-16 1973-04-17 Howmet Corp Method of casting using a mold having a refractory coating thereon

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3973750A (en) * 1972-10-06 1976-08-10 Office National D'etudes Et De Recherches Aerospatiales (O.N.E.R.A.) Casting mold for directional solidification of an alloy
US3908733A (en) * 1973-10-26 1975-09-30 United Technologies Corp Method and apparatus for control of alloy in columnar grain castings
US3888301A (en) * 1974-06-07 1975-06-10 United Aircraft Corp Multi-part mold clamp
US3927710A (en) * 1974-08-21 1975-12-23 United Technologies Corp Joining of multi-section ceramic molds
US4147201A (en) * 1975-02-20 1979-04-03 Office National D'etudes Et De Recherches Aerospatiales (O.N.E.R.A.) Method of manufacturing of a metallurgical mold
US4250943A (en) * 1975-02-20 1981-02-17 Office National D'etudes Et De Recherches Aerospatiales Method of manufacturing of a metallurgical mould
US3972367A (en) * 1975-06-11 1976-08-03 General Electric Company Process for forming a barrier layer on ceramic molds suitable for use for high temperature eutectic superalloy casting
US4031945A (en) * 1976-04-07 1977-06-28 General Electric Company Process for making ceramic molds having a metal oxide barrier for casting and directional solidification of superalloys
US5337800A (en) * 1992-09-09 1994-08-16 Cook Arnold J Reactive coating
US20040232582A1 (en) * 2001-04-17 2004-11-25 Fts Systems, Llc (A/K/A Fts, Llc) Method and apparatus with redundancies, for treating substrate plastic parts to accept paint without using adhesion promoters
US20040176715A1 (en) * 2003-03-04 2004-09-09 Nelson Ronald E. Self adjusting knee brace
US20050045301A1 (en) * 2003-08-28 2005-03-03 Bullied Steven J. Investment casting
US7201212B2 (en) * 2003-08-28 2007-04-10 United Technologies Corporation Investment casting
CN106363131A (zh) * 2016-09-21 2017-02-01 上海万泽精密铸造有限公司 钛合金铸造用陶瓷型壳面层改性的方法
WO2022157331A1 (en) * 2021-01-22 2022-07-28 Oerlikon Metco Ag, Wohlen Transplanted thermal barrier coating system

Also Published As

Publication number Publication date
IL41118A0 (en) 1973-02-28
SE403058B (sv) 1978-07-31
CA981416A (en) 1976-01-13
BE796024A (fr) 1973-06-18
AU466583B2 (en) 1974-06-20
AU5027372A (en) 1974-06-20
IT983513B (it) 1974-11-11
FR2174858B1 (ru) 1977-04-29
DE2303181A1 (de) 1973-09-20
CH585077A5 (ru) 1977-02-28
IL41118A (en) 1977-04-29
GB1405768A (en) 1975-09-10
FR2174858A1 (ru) 1973-10-19

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