US3552479A - Casting process involving cooling of a shell mold prior to casting metal therein - Google Patents

Casting process involving cooling of a shell mold prior to casting metal therein Download PDF

Info

Publication number
US3552479A
US3552479A US684916A US3552479DA US3552479A US 3552479 A US3552479 A US 3552479A US 684916 A US684916 A US 684916A US 3552479D A US3552479D A US 3552479DA US 3552479 A US3552479 A US 3552479A
Authority
US
United States
Prior art keywords
casting
shell mold
mold
alloy
metal
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
US684916A
Other languages
English (en)
Inventor
John Hockin
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.)
MARTIN METALS CO
Original Assignee
MARTIN METALS CO
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 MARTIN METALS CO filed Critical MARTIN METALS CO
Application granted granted Critical
Publication of US3552479A publication Critical patent/US3552479A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D18/00—Pressure casting; Vacuum casting
    • B22D18/06—Vacuum casting, i.e. making use of vacuum to fill the mould

Definitions

  • the present invention is concerned with casting of alloys and, more particularly, with the casting of nick'el-base, chromium-containing super alloys in ceramic shell molds.
  • a shell mold is a mold havinga coherent ceramic body adapted to contain'molten'metal within walls having thicknessesbetween aboutone-eighth to about one-halfinch.
  • a shell mold coating awax model of'a turbine blade with refractory such as zircon -or alumina such as zircon -or alumina.
  • the coating is provided byfi'rst dipping the model into "a' slurry of very finely-divided refractory, removing the slurry coated model from "the dipping bath and stuccoing the slurry coated model with particulate refractory having a' particle size substantially in excess of the particle size'of the refractory in the' slurry.. This dipping and stuccoing process is repeated until the required thickness of approximately three-eighths inch is";obtain ed. After the coating onthe model is dry .and a temporary bond is obtained, the model can be removed by dissolution, melting, burning or temperatures, a phenomenon termed creep occurs.
  • Creep is generally considered to be an irreversible deformation, the magnitude of which deformation is dependent in part upon time and in part upon temperature and stress. Eventually, creep will cause failure either by causing the metal part to extend beyond limits of tolerance or, in drastic cases, to fracture.
  • the higher the temperature of use the more severe is the creep problem assuminga constant applied stress. Conversely, generally speaking, the greater the stress, the more severe is the creep problem assuming a constant temperature.
  • the resistance of a metal to creep at various temperatures is not usually uniformly high or low. It is not only possible but usual for a metal part to exhibit good creep resistance at l,800 F. and relatively poor creep reslstanceat l,400 F. Conversely, a part made of identical metal chemistry but somewhat difl'erent prior thermal history may have relatively poor creep resistance at l,800 F. and relatively good creep resistance at l,800 F. and relatively good creep resistance at -l ,400 F,
  • the present invention is concerned with one of these factors,
  • the solidification rate and the rate of cooling of precision cast metal, cast into ceramic shell molds such as described hereinbefore are primarily affected by the pouring temperature of the metal and the initial mold temperature -at'the start of casting. It is known that with many nickel-base alloys of the kind in question, if relatively slow cooling rates are used by providing an initial high mold temperature, good 1-,400 F. creep the like.yThe shell mold is then matured and provided with a ceramic bond by firing at an elevated temperature; for example, at about 1,600 to 2,000 F.
  • shell molds' In physical form, shell molds','the manufacture of which is described generally; in the preceding paragraph, include not only a cavity in the shape'of the article to be'mold'e'd but also connecting cavities in the shapesof feeders, 'risers,.spru es, pouring basins and the like suchthat all of ,the features required by proper casting technique are incorporated in the ceramic shell mold. Quite often, but not necessarily, the shell mold is employed in vacuum casting. ltis well known that the normal atmosphere can contaminate inost metals when the metal is in the molten state. With common metals'such'as steel, it is quite usual to at least partially protect the molten metal from atmospheric contamination by melting and pour- .ing under a slag cover.
  • alloys contain eyen relatively small amounts of elements, such as titanium, aluminum, zirconium, boron and the like, it is highly'advantageous to melt and cast such'alloys in vacuum. Again, bynow, vacuum melting and casting of alloys sensitive to atmospheric contamination is well known in the art. Further, it is, of course, well known in the art to vacuum cast 'such alloys into ceramic shell molds of the type described hereinbefore.
  • Certainnickel-base alloys containing, chromium (primarily for'oxidation resistance) and other elements designed to provide'hardening by means of solid solution strengthening, carbide strengthening and gamma pri'rneprecipitation are especially adapted to becast in vacuum.
  • Many of such alloys are net forgeable except in an extremely limitedway and are par-- I jected to stress below their-yield point especiallyat elevated rupture properties and ductility can be provided. Under such casting conditions the creep resistance'properties at l,800 F of the cast metal are relatively low. Conversely, if a low mold temperature is used to'provide extremely rapid cooling, ex-
  • tremely good creep properties can be provided for use at l,800 F. but only at a sacrifice of properties at l ,400 F., such as ductility. If it were possible to'design turbine engines to operate uniformly at a single high temperature the aforedescribedcasting vargaries would provide no difficulty. in practice, however, the high temperature section of a-jet engine does not operate at a-single temperature. The temperature of a single turbine blade in the hot section-of a jet engine can varyin different spots across its cross section and in different spots along its length. It is not impossible that a single practical operating turbine blade would involve in different areas thereof temperatures ranging from 1,400 to l,800 F. at any given moment of operation.
  • the temperatures in the hot section of a turbine engine can vary over the range of from' ambient atmospheric temperatures to up to 2,000 F. For these reasons it is important to provide cast structures having optimum properties over a reasonably wide range of elevated temperatures.
  • the present invention is concerned with vthe solution of this problem which, as far as I am aware, has not heretofore been solved in a satisfactory manner on a commercial scale.
  • thepresent invention contemplates the process of casting and the'product produced thereby wherein an alloy (metal), selected from the group of certain nickelbase alloys specified hereinafter,-in molten form at a tempera ture of about 200 F. above the freezing point thereof is poured into a ceramic shell mold characterized just prior to the-start of pouring by-having different temperatures in different areas in and on the'mold with the spread-of the temperatures being in the range of about l to 350 in TABLE III Fahrenheit units. and the poured metal is thereafter allowed to cool and solidify in said shell mold.
  • an alloy selected from the group of certain nickelbase alloys specified hereinafter
  • m n the maximum of said temperature spread is about 800 in Chrommm 8-18 Fahrenheit units below the freezing point of the metal and the gobalt 0-20 ungsten 0-13. 5 minimum IS about 1,100 In Fahrenheit units below the freez- Molybdenum ing point of the metal.
  • the freezing point of an alloy (metal) shall be con- Tit i 0-6 sidered to be the liquidus of the particular alloy composition Aluminum plus titanium 6-11 employed. C rbon 0. 02-0.
  • the nickel'base alloys particularly adapted to be employed P 02 in the process of the present invention are nickel-base.
  • gg gi chromium-containing alloys having in the solid state a gamma 31 matrix, a gamma prime precipitate dispersed throughout the '::III:IIII: matrix upon initial solidification of the alloy from the molten (j l bi 0-6 state. elements in solid solution to strengthen said gamma Nickel 1 Balance matrix and carbide particles dispersed throughout the alloy l Together with impurities and incidental elements which do not adbody.
  • such alloys will contain at least verse/1y meet the utility of the alloys about 5 percent of an element selected from the group consisting of titanium and aluminum or both, at least 2 percent of an element selected from the group of molybdenum, tungsten. columbium, or tantalum. at least about 0.02 percent carbon
  • a boron and z co um. table [II are cooled from the molten state, carbide phases are for example up to about 0. 2 perce t f bOfOn n p to about initially formed in the solid metal followed by gamma prime 0.3 percent of zirconium.
  • such alloys can re ipitate.
  • alloys adapted to be used in the contain up to about 2 perc n Cob l and may HIB H process of the present invention are not amenable to be soluamounts of iron, manganese, silicon and other incidental elenon-treated and aged to redistribute and/or reform carbide ments which do not affect the basic characteristics of the aland gamma prime phases. loys.
  • the composition of In carrying out the process of the present invention one of such alloys will be balanced so as to avoid the formation of the easiest ways to achieve the required temperature profile of embrittling phases during exposure to elevated temperatures.
  • the shell mold as described hereinbefore, is to initially heat A typical alloy which is particularly adapted to be treated by the mold to a temperature of l.900 F. and then cool the mold, the process of the present invention is that alloy known in advantageously in vacuum, for about2 to about l5 minutes or commerce as B-l900 which has a nominal composition as set more before casting metal therein. If the cooling is accomforth in table I. plished primarily by radiation, it is thought that the inner walls of the mold should cool slower than the outer walls because the heat sinks to which the inner walls will be radiating (each TAB I other) will be much higher in temperature than the sinks to Perqent which the outer walls radiate.
  • the complexity of the cooling process in- Nickel Balance troduces temperature variations throughout the whole mold whereby certain areas are hotter by up to about 300 in Fahrenheit units than the coolest areas of the mold.
  • the nominal compositions of other alloys which can be emmetal such as B-l900 is cast using a pouring temperature of ployed in the process of the present invention are set forth in about 200 F. above the freezing point into the mold cooled table II. from l.900 F. to provide the aforementioned thermal TABLE II Alloy 01' Mo Cb Ti Al B Zr Co C Ni W Ta Fe V INCONEL alloy 713C 2. 0 8 6.1 0. 012 0.10 12 Balance MAR M 2 alloy 200- 1 2 5 0.015 0.05 10 0.
  • cooling period is about 3 to about minutes. for example about 5 to about 9 minutes, to optimize all properties.
  • the present invention contemplates casting metal into a shell mold having the defined temperature dif- Table IV shows that. by using the process of the present invention. one can provide structures made from alloy B-l900 having an excellent combination of high temperature mechanical characteristics, the measured characteristics ferentials no matter how such a condition is created. The 5 being essentially equal if not superior to the optimum stresssequence of practical steps of the process of the present inven tion involving cooling for about 2 to about minutes is depicted in schematic fon'n on the drawing.
  • Example I rupture characteristics obtainable at either 1,400 F. or l,800 F. using prior molding techniques A or B.
  • Example ll An alloy having the chemistry of that alloy identified in table ll as'MAR M alloy 246 was melted and cast in exactly the same fashion as was described in Example 1 except that the mold was allowed to cool for about [0 minutes.
  • a shell mold, as described hereinbefore, containing a plurality of cavities conforming to the shape of stress-rupture specimens was heated to 1,900 F. and allowed to cool for about seven with the process of the present invention.
  • Nom.p.s.l. pounds per square inch.
  • Example lll As a final example of the utility and unobviousness of the present invention a relatively newly developed high temperature nickel-base chromium-containing alloy was cast into test bars using a ceramic shell mold cooled-back from l.900 F.
  • TABLE VI in the range of about l,200 F. to 2.000 F. and comprising, as a solid. a matrix gamma phase, a gamma prime phase and a carbide phase, comprising the steps of:
  • Table VI shows that the reduction-of-area of the relatively newly developed alloy in hot tensile test at l,600 F. is greatly improved, e.g. over I00 percent improvement, without detriment to other characteristics significant from an engineering standpoint. At least one major jet engine manufacturer considers the reduction-of-area during hot tensile testing to be a highly significant factor in determining the suitability of an alloy or alloy structure for hot stage jet engine service. Table VI shows that hot tensile reduction-of-area can be raised from l0.5 percent up to 22.7 percent and even higher for this particular alloy by means of the present invention without significantly varying the stress rupture life and accompanying reduction-of-area at 1,800" F. under a load of 27.5 k.s.i.
  • a refractory shell mold initially preheating a refractory shell mold to about 1.900" F. in vacuum; causing said initially preheated refractory shell mold to cool by radiation in said vacuum from about 1.900 F. for about 2 to about 15 minutes to provide a refractory shell mold, characterized by having a diversity of temperatures at diverse locations therein and thereon with a spread of about l00 to 350 in Fahrenheit units between the maximum and the minimum of said temperatures, said maximum and minimum of said temperatures being between about 400 and l,200 in Fahrenheit units below the freezing point of said alloy;

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Manufacture Of Alloys Or Alloy Compounds (AREA)
  • Turbine Rotor Nozzle Sealing (AREA)
US684916A 1967-11-22 1967-11-22 Casting process involving cooling of a shell mold prior to casting metal therein Expired - Lifetime US3552479A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US68491667A 1967-11-22 1967-11-22

Publications (1)

Publication Number Publication Date
US3552479A true US3552479A (en) 1971-01-05

Family

ID=24750073

Family Applications (1)

Application Number Title Priority Date Filing Date
US684916A Expired - Lifetime US3552479A (en) 1967-11-22 1967-11-22 Casting process involving cooling of a shell mold prior to casting metal therein

Country Status (2)

Country Link
US (1) US3552479A (enrdf_load_stackoverflow)
GB (1) GB1234584A (enrdf_load_stackoverflow)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3669180A (en) * 1971-01-20 1972-06-13 United Aircraft Corp Production of fine grained ingots for the advanced superalloys
US3677331A (en) * 1969-07-14 1972-07-18 Martin Marietta Corp Casting process for nickel base alloys
US4033401A (en) * 1974-05-29 1977-07-05 Sulzer Brothers Limited Precision casting process
US20030011093A1 (en) * 2000-02-23 2003-01-16 Sandor Cser Method for production of an oxidation inhibiting titanium casting mould
US20050063827A1 (en) * 2002-10-09 2005-03-24 Ishikawajima-Harima Heavy Industries Co., Ltd. Rotating member and method for coating the same
US20060035068A1 (en) * 2002-09-24 2006-02-16 Ishikawajima-Harima Heavy Industries Co., Ltd. Method for coating sliding surface of high-temperature member, high-temperature member and electrode for electro-discharge surface treatment
US20100086398A1 (en) * 2002-09-24 2010-04-08 Ihi Corporation Method for coating sliding surface of high-temperature member, high-temperature member and electrode for electro-discharge surface treatment
US20200147850A1 (en) * 2018-11-14 2020-05-14 Meissner Ag Modell- Und Werkzeugfabrik Casting tool, for example core shooting tool or permanent mould, and corresponding casting method

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2283888C2 (ru) * 2001-11-13 2006-09-20 Фундасьон Инасмет Изготовление продукта из конструкционных металлических материалов, армированных карбидами

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3153824A (en) * 1961-12-29 1964-10-27 Martin Metals Corp Method of casting metals
US3200455A (en) * 1962-04-04 1965-08-17 Howe Sound Co Method of shell mold casting
US3274652A (en) * 1963-08-23 1966-09-27 Distington Engineering Co Method of constructing a casting mould by determination of isothermal pattern
US3279006A (en) * 1963-12-30 1966-10-18 Martin Metals Company Method of preparing composite castings

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3153824A (en) * 1961-12-29 1964-10-27 Martin Metals Corp Method of casting metals
US3200455A (en) * 1962-04-04 1965-08-17 Howe Sound Co Method of shell mold casting
US3274652A (en) * 1963-08-23 1966-09-27 Distington Engineering Co Method of constructing a casting mould by determination of isothermal pattern
US3279006A (en) * 1963-12-30 1966-10-18 Martin Metals Company Method of preparing composite castings

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3677331A (en) * 1969-07-14 1972-07-18 Martin Marietta Corp Casting process for nickel base alloys
US3669180A (en) * 1971-01-20 1972-06-13 United Aircraft Corp Production of fine grained ingots for the advanced superalloys
US4033401A (en) * 1974-05-29 1977-07-05 Sulzer Brothers Limited Precision casting process
US20030011093A1 (en) * 2000-02-23 2003-01-16 Sandor Cser Method for production of an oxidation inhibiting titanium casting mould
US6802358B2 (en) * 2000-02-23 2004-10-12 Sandor Cser Method for production of an oxidation inhibiting titanium casting mould
US20060035068A1 (en) * 2002-09-24 2006-02-16 Ishikawajima-Harima Heavy Industries Co., Ltd. Method for coating sliding surface of high-temperature member, high-temperature member and electrode for electro-discharge surface treatment
US20100086398A1 (en) * 2002-09-24 2010-04-08 Ihi Corporation Method for coating sliding surface of high-temperature member, high-temperature member and electrode for electro-discharge surface treatment
US9187831B2 (en) 2002-09-24 2015-11-17 Ishikawajima-Harima Heavy Industries Co., Ltd. Method for coating sliding surface of high-temperature member, high-temperature member and electrode for electro-discharge surface treatment
US9284647B2 (en) 2002-09-24 2016-03-15 Mitsubishi Denki Kabushiki Kaisha Method for coating sliding surface of high-temperature member, high-temperature member and electrode for electro-discharge surface treatment
US20050063827A1 (en) * 2002-10-09 2005-03-24 Ishikawajima-Harima Heavy Industries Co., Ltd. Rotating member and method for coating the same
US7537809B2 (en) * 2002-10-09 2009-05-26 Ihi Corporation Rotating member and method for coating the same
US20090200748A1 (en) * 2002-10-09 2009-08-13 Ihi Corporation Rotating member and method for coating the same
US20100124490A1 (en) * 2002-10-09 2010-05-20 Ihi Corporation Rotating member and method for coating the same
US7918460B2 (en) 2002-10-09 2011-04-05 Ihi Corporation Rotating member and method for coating the same
US20200147850A1 (en) * 2018-11-14 2020-05-14 Meissner Ag Modell- Und Werkzeugfabrik Casting tool, for example core shooting tool or permanent mould, and corresponding casting method

Also Published As

Publication number Publication date
GB1234584A (enrdf_load_stackoverflow) 1971-06-03

Similar Documents

Publication Publication Date Title
US3260505A (en) Gas turbine element
US3061426A (en) Creep resistant alloy
US4222794A (en) Single crystal nickel superalloy
US5173255A (en) Cast columnar grain hollow nickel base alloy articles and alloy and heat treatment for making
US3149411A (en) Composite materials containing cemented carbides
US7824606B2 (en) Nickel-based alloys and articles made therefrom
US2698990A (en) Chromium-alumina metal ceramics
US20110052443A1 (en) Nickel-Based Superalloys and Articles
US2977222A (en) Heat-resisting nickel base alloys
US3552479A (en) Casting process involving cooling of a shell mold prior to casting metal therein
US3677747A (en) High temperature castable alloys and castings
CN102625856A (zh) 镍基超耐热合金和由所述超耐热合金制成的部件
US2829048A (en) High damping alloy and members prepared therefrom
US2469718A (en) Alloys
EP0362661B1 (en) Cast columnar grain hollow nickel base alloy article and alloy and heat treatment for making
JPS6250429A (ja) 高温鍛造金型用ニツケル基鋳造合金
US2766156A (en) Heat-treatment of nickel-chromiumcobalt alloys
US3107167A (en) Hot workable nickel base alloy
US5916384A (en) Process for the preparation of nickel base superalloys by brazing a plurality of molded cavities
CN111373063A (zh) 具有高抗氧化性的用于燃气涡轮应用的合金
US3145124A (en) Heat treatment of nickel chromiumcobalt alloys
US4092183A (en) Directionally solidified castings
US2743175A (en) Precision casting alloy
US3816111A (en) Chromium-base alloy for making a chill-mold and a process of making same
US1698934A (en) Alloy and method of making the same