US3908733A - Method and apparatus for control of alloy in columnar grain castings - Google Patents

Method and apparatus for control of alloy in columnar grain castings Download PDF

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Publication number
US3908733A
US3908733A US410146A US41014673A US3908733A US 3908733 A US3908733 A US 3908733A US 410146 A US410146 A US 410146A US 41014673 A US41014673 A US 41014673A US 3908733 A US3908733 A US 3908733A
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US
United States
Prior art keywords
cavity
mold
alloy
reservoir
article
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
US410146A
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English (en)
Inventor
Geoffrey R Brazer
Patrick M Curran
Bruce E Terkelsen
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
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United Technologies Corp
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Filing date
Publication date
Application filed by United Technologies Corp filed Critical United Technologies Corp
Priority to US410146A priority Critical patent/US3908733A/en
Priority to CH1389374A priority patent/CH600973A5/xx
Priority to AU74383/74A priority patent/AU483146B2/en
Priority to NLAANVRAGE7413682,A priority patent/NL174330C/xx
Priority to SE7413149A priority patent/SE410411B/xx
Priority to IL45917A priority patent/IL45917A/en
Priority to GB46069/74A priority patent/GB1487598A/en
Priority to FR7435640A priority patent/FR2248897B1/fr
Priority to DE2450602A priority patent/DE2450602C2/de
Priority to CA212,277A priority patent/CA1035538A/en
Priority to JP49123272A priority patent/JPS5074521A/ja
Priority to IT28777/74A priority patent/IT1025186B/it
Application granted granted Critical
Publication of US3908733A publication Critical patent/US3908733A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • 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

Definitions

  • a reservoir which is shaped to minimize depletion of the element is positioned above the article cavity in the mold to supply alloy to the top of the article cavity.
  • the molten alloy in the reservoir serves to enrich the solidifying alloy in the article forming portion of the mold with the depleted reactive ingredient.
  • the molten alloy is depleted in hafnium during the solidification cycle. This is especially true in casting columnar grained articles as in the VerSnyder US. Pat. No. 3,260,505 or the particular type of columnar grain single crystal of the Piearcey US. Pat. No. 3,494,709 since such casting necessitates a controlled cooling of the alloy from the bottom to the top of the mold. In such casting procedures it is found that the lower portion of the cast article has the percentage of hafnium that is provided in the alloy as it is poured but that further up in the cast article the hafnium content is found to be lower.
  • hafnium content between 1.75 and 2.50 weight percent.
  • hafnium contents as low as 1.43 percent have been observed at the tip end of the airfoil with hafnium content at the base 2.50 percent. Such a low percentage of hafnium at the tip is undesirable.
  • a reservoir of molten alloy is located in the mold above the article cavity and this reservoir has a large volume to surface ratio so that the hafnium will be depleted to a lesser extent.
  • the invention also includes the process ofmaking castings of high temperature superalloys with an added ingredient such as hafnium which reacts with the mold and cores so that the ingredient is depleted during solidification, the process includes the supplying of the ingredient rich alloy from a reservoir located in the mold above the article cavity, the alloy in the reservoir remaining molten-until all the alloy in the article cavity is solidified.
  • FIG. 1 is a vertical sectional view through a mold embodying the invention.
  • FIG. 2 is a sectional view along the line 22 of FIG.
  • FIG. 3 is a sectional view along the line 33 of FIG.
  • FIG. 4 is a vertical sectional view of a modification for making hollow blades.
  • FIG. 5 is a sectional view along line 5--5 of FIG. 4.
  • the mold 2 when ready for useis positioned on the chill plate 4 and has an open lower end 6 so that when molten alloy is poured into the ingredient is reduced during the solidification process.
  • One such ingredient is the element hafniumanda nominal composition of one of the superalloysto whichhaf i nium is added as follows:
  • Titanium I Nickel Balance The molds used in the casting process contain oxide'f f I materials such as silicon dioxide that react with the haf nium in the molten alloy. It has been found for example.-
  • the cast article, the tip of the blade may be as low as 1.40 percent and this is too low to produce the desired ductility in a cast article.
  • the purpose for which the hafnium is added is to increase ductility as described in the Sullivan et al. U.S. Pat. No. 3,711,337 above mentioned.
  • the cast alloy As it is undesirable for the cast alloy to contain more than a predetermined percentage of hafnium, for example 2.5 percent as above described, the amount of hafnium in the master alloy as poured cannot be above this value. Thus, the net loss of the hafnium from the upper portion of the casting must be reduced.
  • the mold is constructed with a reservoir which is sized to reduce the amount of depletion.
  • the mold has a growth zone 8 at the bottom in which the crystalline growth is converted into columnar grains, this growth zone being removed after the casting is solid substantially along the dotted line 9 in the drawing.
  • the root zone 10 of the cast article Above the growth Zone in FIG. 1 is the root zone 10 of the cast article and above this is the shroud or platform cavity for the turbine blade being cast.
  • the platform cavity Above the platform cavity is the cavity 12 for the airfoil or gas contacting portion of the blade, this portion being relatively thin as shown in FIG. 2 and airfoil shaped in cross section.
  • a substantial surface area is exposed to the oxide surface area of the mold and permits reaction of the hafnium in the molten alloy with the material in the mold with resultant depletion of the hafnium.
  • a riser portion 14 relatively short in height and then a reservoir 16 providing a significant volume for a supply of the molten alloy.
  • the reservoir 16 communicates through the riser 14 over the entire area of the tip of the blade or airfoil portion 12 of the article portion of the mold.
  • the riser 14 is shown as increasing in area from the top of the blade portion 14 to the base of the reservoir and the latter is broader at all points than the thickness of the tip of the blade and is slightly larger than the chord of the blade portion and extends beyond both the leading and trailing edges of the blade cross section at the tip. This is emphasized by showing the tip opening of the blade in the showing of FIG. 3, the section through the reservoir.
  • This reservoir will supply molten alloy to the top portion of the article cavity as the alloy is depleted in hafnium during solidification thereby supplying an alloy with an adequate quantity of hafnium to the upper portion of the cast article.
  • This reservoir 16 is preferably somewhat similar in cross sectional shape to the cavity 12 but larger as shown in FIG. 3 preferably at least twice as large in horizontal cross section.
  • This reservoir is of significant height, for example, from I to 1 /2 inches in height for a blade that may have an airfoil portion from 2 to 3 inches tall.
  • the riser portion provides a location at which the blade when cast may be cut off from the cast alloy in the reservoir.
  • a gate 18 through which the mold cavity is filled the latter communicating with a filling sprue, not shown.
  • the mold In use the mold is positioned on the chill plate and in the furnace having means for heating the mold to a temperature above the melting point of the alloy. After the mold is so heated, the alloy with about 300F of superheat is poured into the mold to fill it at least to the top of the reservoir 16. Solidification starts at the chill plate and continues upwardly with columnar grains or a single crystal columnar grain formed in the growth zone. By controlling the temperature gradient in the mold as described in the VerSnyder or the Piearcey patent, the columnar growth continues through the mold into the reservoir so that the entire blade structure is columnar grained or single crystal.
  • the hafnium in the molten alloy reacts with the mold and thus the hafnium content is depleted to a greater degree toward the top of the article cavity 12 thereby reducing the percentage of hafnium.
  • the depletion is reduced in the alloy in the reservoir thus as the alloy solidifies within the blade cavity it is enriched from the still hafnium-rich alloy in the reservoir.
  • the percentage of hafnium in the airfoil portion of the blade is not reduced below the desired minimum and the ductility required in the blade particularly near the tip is obtained.
  • the invention is equally effective in making hollow blades as shown in the cross section in FIGS. 4 and 5.
  • the mold 2' has a core portion 20 which is also high in oxides such as silicon dioxide which reacts with the hafnium in the molten alloy. Since this core does not extend upward into the reservoir 16' at the top of the article cavity 12' in the mold as shown in FIG. 4, the same results are obtained in the finished article with the resultant satisfactory percentage of hafnium in the finished cast blade even at the top thereof.
  • the term mold is intended to include the core as an essential part of the mold.
  • the description is directed to a mold for making a turbine blade and to the use of such a mold it is equally adapted to making other articles such as stationary turbine vanes and other geometries having high surface area to volume ratios.
  • the significant feature is that the reservoir be of such a size that the hafnium therein is not depleted below the desired minimum during the solidification cycle. In this way there is an adequate supply of hafnium rich alloy to enrich the top of the article cavity during solidification.
  • connection from the article cavity to the secondary cavity increasing in dimension in all directions from the maximum area of the article cavity at the top to the larger in-area secondary cavity, the connection providing a gradual blending from the top of the article cavity to the secondary cavity;
  • the mold for casting gas turbine blades from high temperature alloys having as an ingredient an element that reacts with the mold material and is thereby depleted during solidification said mold including:
  • a large reservoir cavity directly above and communicating directly with the airfoil shaped cavity the communication gradually increasing in dimension in all lateral directions from bottom to top
  • said reservoir cavity being shaped to have a large volume! to-surface area ratio, and being large enough to prevent depletion of the reactive element therein below the required amount during solidification of the alloy, said reservoir cavity being greater in all lateral directions from the maximum area of the top of the airfoil cavity and the communication providing a gradual blending of dimension from the top of the airfoil cavity to the reservoir cavity.
  • a mold as in claim 5 in which the reservoir cavity is also an airfoil shape and larger in cross sectional area than the end of the blade cavity communicating therewith said secondary cavity extending laterally in all directions beyond the top of the airfoil shaped cavity.
  • a mold as in claim 5 in which the bottom of the mold is open to rest on a chill plate.
  • a mold as in claim 5 in which the reservoir is simi lar in cross section to and communicates with the entire cross section of the tip of the airfoil shaped cavity.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Turbine Rotor Nozzle Sealing (AREA)
US410146A 1973-10-26 1973-10-26 Method and apparatus for control of alloy in columnar grain castings Expired - Lifetime US3908733A (en)

Priority Applications (12)

Application Number Priority Date Filing Date Title
US410146A US3908733A (en) 1973-10-26 1973-10-26 Method and apparatus for control of alloy in columnar grain castings
CH1389374A CH600973A5 (de) 1973-10-26 1974-10-16
AU74383/74A AU483146B2 (en) 1973-10-26 1974-10-16 Method and apparatus for control of alloy in columnar grain castings
NLAANVRAGE7413682,A NL174330C (nl) 1973-10-26 1974-10-18 Gietvorm ter vervaardiging van gietstukken met stengelkristalstructuur van een hogetemperatuurlegering.
SE7413149A SE410411B (sv) 1973-10-26 1974-10-18 Forfarande och gjutform for framstellning av gjutprodukter med pelarformiga korn
IL45917A IL45917A (en) 1973-10-26 1974-10-23 Control of alloy composition in columnar grain castings containing an element which reacts with the mold
GB46069/74A GB1487598A (en) 1973-10-26 1974-10-24 Control of alloy in columnar grain castings
FR7435640A FR2248897B1 (de) 1973-10-26 1974-10-24
DE2450602A DE2450602C2 (de) 1973-10-26 1974-10-24 Gießform
CA212,277A CA1035538A (en) 1973-10-26 1974-10-25 Control of alloy in columnar grain castings
JP49123272A JPS5074521A (de) 1973-10-26 1974-10-25
IT28777/74A IT1025186B (it) 1973-10-26 1974-10-25 Metodo e stampo per la fabbricazio ne controllata di articoli colati a cristalli colonnari

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US410146A US3908733A (en) 1973-10-26 1973-10-26 Method and apparatus for control of alloy in columnar grain castings

Publications (1)

Publication Number Publication Date
US3908733A true US3908733A (en) 1975-09-30

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ID=23623421

Family Applications (1)

Application Number Title Priority Date Filing Date
US410146A Expired - Lifetime US3908733A (en) 1973-10-26 1973-10-26 Method and apparatus for control of alloy in columnar grain castings

Country Status (11)

Country Link
US (1) US3908733A (de)
JP (1) JPS5074521A (de)
CA (1) CA1035538A (de)
CH (1) CH600973A5 (de)
DE (1) DE2450602C2 (de)
FR (1) FR2248897B1 (de)
GB (1) GB1487598A (de)
IL (1) IL45917A (de)
IT (1) IT1025186B (de)
NL (1) NL174330C (de)
SE (1) SE410411B (de)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3965963A (en) * 1973-11-16 1976-06-29 United Technologies Corporation Mold and process for casting high temperature alloys
US4475582A (en) * 1982-01-27 1984-10-09 United Technologies Corporation Casting a metal single crystal article using a seed crystal and a helix
US4988266A (en) * 1988-03-14 1991-01-29 Hitachi, Ltd. Gas turbine and shroud for gas turbine
US20080099177A1 (en) * 2006-10-31 2008-05-01 General Electric Company Investment casting process and apparatus to facilitate superior grain structure in a DS turbine bucket with shroud
CN102756117A (zh) * 2012-08-07 2012-10-31 无锡蠡湖叶轮制造有限公司 铝合金无氧化皮浇注装置
CN103143678A (zh) * 2013-04-01 2013-06-12 东方电气集团东方汽轮机有限公司 一种用于优化高温合金叶片定向柱晶组织的模壳
US8641381B2 (en) 2010-04-14 2014-02-04 General Electric Company System and method for reducing grain boundaries in shrouded airfoils
US20140190653A1 (en) * 2011-08-19 2014-07-10 Instytut Odlewnictwa Method for producing investment castings
CN111566317A (zh) * 2018-01-11 2020-08-21 西门子股份公司 燃气涡轮动叶和用于制造动叶的方法

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2978927B1 (fr) 2011-08-09 2013-09-27 Snecma Procede de fonderie de pieces metalliques monocristallines

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3620289A (en) * 1968-08-05 1971-11-16 United Aircraft Corp Method for casting directionally solified articles
US3633648A (en) * 1970-04-24 1972-01-11 United Aircraft Corp Method of casting in investment molds having a radiation shield
US3802482A (en) * 1972-03-09 1974-04-09 United Aircraft Corp Process for making directionally solidified castings
US3810504A (en) * 1971-03-26 1974-05-14 Trw Inc Method for directional solidification

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL136758C (de) * 1963-10-21 1900-01-01
US3494709A (en) * 1965-05-27 1970-02-10 United Aircraft Corp Single crystal metallic part
US3711337A (en) * 1970-12-16 1973-01-16 United Aircraft Corp Columnar-grained nickel-base superalloy castings

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3620289A (en) * 1968-08-05 1971-11-16 United Aircraft Corp Method for casting directionally solified articles
US3633648A (en) * 1970-04-24 1972-01-11 United Aircraft Corp Method of casting in investment molds having a radiation shield
US3810504A (en) * 1971-03-26 1974-05-14 Trw Inc Method for directional solidification
US3802482A (en) * 1972-03-09 1974-04-09 United Aircraft Corp Process for making directionally solidified castings

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3965963A (en) * 1973-11-16 1976-06-29 United Technologies Corporation Mold and process for casting high temperature alloys
US4475582A (en) * 1982-01-27 1984-10-09 United Technologies Corporation Casting a metal single crystal article using a seed crystal and a helix
US4988266A (en) * 1988-03-14 1991-01-29 Hitachi, Ltd. Gas turbine and shroud for gas turbine
US20080099177A1 (en) * 2006-10-31 2008-05-01 General Electric Company Investment casting process and apparatus to facilitate superior grain structure in a DS turbine bucket with shroud
US8641381B2 (en) 2010-04-14 2014-02-04 General Electric Company System and method for reducing grain boundaries in shrouded airfoils
US20140190653A1 (en) * 2011-08-19 2014-07-10 Instytut Odlewnictwa Method for producing investment castings
CN102756117A (zh) * 2012-08-07 2012-10-31 无锡蠡湖叶轮制造有限公司 铝合金无氧化皮浇注装置
CN102756117B (zh) * 2012-08-07 2016-01-27 无锡蠡湖叶轮制造有限公司 铝合金无氧化皮浇注装置
CN103143678A (zh) * 2013-04-01 2013-06-12 东方电气集团东方汽轮机有限公司 一种用于优化高温合金叶片定向柱晶组织的模壳
CN103143678B (zh) * 2013-04-01 2015-02-18 东方电气集团东方汽轮机有限公司 一种用于优化高温合金叶片定向柱晶组织的模壳
CN111566317A (zh) * 2018-01-11 2020-08-21 西门子股份公司 燃气涡轮动叶和用于制造动叶的方法
US11396817B2 (en) 2018-01-11 2022-07-26 Siemens Energy Global GmbH & Co. KG Gas turbine blade and method for producing such blade
CN111566317B (zh) * 2018-01-11 2023-03-03 西门子能源环球有限责任两合公司 燃气涡轮动叶和用于制造动叶的方法

Also Published As

Publication number Publication date
DE2450602A1 (de) 1975-04-30
CA1035538A (en) 1978-08-01
IT1025186B (it) 1978-08-10
SE7413149L (de) 1975-04-28
NL7413682A (nl) 1975-04-29
JPS5074521A (de) 1975-06-19
FR2248897A1 (de) 1975-05-23
GB1487598A (en) 1977-10-05
FR2248897B1 (de) 1980-05-30
DE2450602C2 (de) 1982-12-30
CH600973A5 (de) 1978-06-30
IL45917A (en) 1977-07-31
SE410411B (sv) 1979-10-15
AU7438374A (en) 1976-04-29
IL45917A0 (en) 1975-05-22
NL174330C (nl) 1984-06-01
NL174330B (nl) 1984-01-02

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