WO1989002326A1 - Systeme de coulage a mousse evaporable utilisant un alliage d'aluminium et de silicium hypereutectique - Google Patents

Systeme de coulage a mousse evaporable utilisant un alliage d'aluminium et de silicium hypereutectique Download PDF

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Publication number
WO1989002326A1
WO1989002326A1 PCT/US1988/002864 US8802864W WO8902326A1 WO 1989002326 A1 WO1989002326 A1 WO 1989002326A1 US 8802864 W US8802864 W US 8802864W WO 8902326 A1 WO8902326 A1 WO 8902326A1
Authority
WO
WIPO (PCT)
Prior art keywords
alloy
pattern
silicon
molten
molten alloy
Prior art date
Application number
PCT/US1988/002864
Other languages
English (en)
Inventor
William G. Hesterberg
Raymond J. Donahue
Terrance M. Cleary
Original Assignee
Brunswick Corporation
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 Brunswick Corporation filed Critical Brunswick Corporation
Priority to BR888807691A priority Critical patent/BR8807691A/pt
Priority to DE88907541T priority patent/DE3885292T2/de
Priority to AT88907541T priority patent/ATE96352T1/de
Publication of WO1989002326A1 publication Critical patent/WO1989002326A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D21/00—Casting non-ferrous metals or metallic compounds so far as their metallurgical properties are of importance for the casting procedure; Selection of compositions therefor
    • B22D21/002—Castings of light metals
    • B22D21/007—Castings of light metals with low melting point, e.g. Al 659 degrees C, Mg 650 degrees C
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/02—Sand moulds or like moulds for shaped castings
    • B22C9/04—Use of lost patterns
    • B22C9/046—Use of patterns which are eliminated by the liquid metal in the mould

Definitions

  • a HYPEREUTECTIC ALUMINUM SILICON ALLOY Aluminum alloys due to their light weight, have been used for casting engine blocks for internal combustion engines.
  • Hypereutectic aluminum silicon alloys containing from 16% to 19% by weight of silicon are known to possess good wear resistant properties, achieved by the precipitated silicon crystals which constitute the primary phase.
  • United States Patent 4,603,665 describes an improved hypereutectic aluminum silicon casting alloy having particular use in casting engine blocks for marine engines.
  • the alloy of the aforementioned patent contains by weight from 16% to 19% silicon, up to 1.4% iron, 0.4% to 0.7% magnesium, up to 0.3% manganese up to 0.37% copper, and the balance aluminum.
  • the ternary aluminum-silicon-copper eutectic is avoided and the resulting alloy has a relatively narrow solidification temperature range.
  • Evaporable foam casting is a known technique in which a pattern formed of an evaporable foam material is supported in a mold and surrounded by an unbonded particulate media, such as sand. When the molten metal contacts the pattern, the foam material vaporizes, with the vapor passing into the interstices of the sand, while the molten metal replaces the void formed by the vaporized foam material.
  • the invention is directed to an evaporable foam casting system using a specific hypereutectic aluminum silicon alloy which, due to its composition, provides a slower solidification rate to provide high quality castings.
  • the invention provides a method of casting, comprising the steps of preparing a molten hypereutectic aluminum silicon alloy containing by weight from 16% to 19% silicon, casting said molten alloy into a mold into contact with an evaporable foam pattern surrounded by a finely divided media, the heat of said molten alloy acting to vaporize said pattern with the vapor passing into and being retained within said i ⁇ edia and said molten alloy filling the void resulting from the vaporization of said pattern, and precipitating the silicon in said alloy as said molten alloy cools to generate heat of crystallization to retard the solidification rate of said alloy and permit said vapor to escape from said molten alloy.
  • the hypereutectic aluminum silicon alloy to be used in the casting method of the invention preferably contains by weight from 16% to 19% silicon, 0.4% to 0.7% magnesium, up to 1.4% iron, up to 0.3% magnesium, up to 0.37% copper and the balance aluminum. Due to the minimum copper content, the ternary aluminum-silicon-copper eutectic is avoided and the alloy has a relatively narrow solidification range, less then 150°F, and preferably less than 100°F.
  • the heat of the alloy will decompose the foam material to vaporize the foam, the vapor passing into the interstices of the surrounding sand and the molten alloy filling the void created by vaporization of the foam material.
  • Solidification of the alloy occurs in conjunction with the heat of crystallization of primary silicon. As the alloy contains a substantial quantity of silicon, the heat of crystallization slows the solidification rate temporarily, thus allowing additional time for the elimination of pattern residue vapors from the molten alloy.
  • the decrease in solidification rate also permits casting of relatively thin sections or filling isolated areas of the pattern located relatively long distances from the ingate.
  • the cast alloy produced by the method of the invention has inherent soundness attributable to the relatively narrow solidification range, good corrosion resistance, and excellent wear resistance due to the precipitated silicon.
  • Fig. 1 is a longitudinal section of a typical evaporable foam casting system that can be utilized
  • Fig. 2 is a section taken along line 2-2 of Fig. 1;
  • FIG. 3 is a perspective view of the sprue.
  • Fig. 1 illustrates a typical evaporative foam casting system which can be utilized. As illustrated, the casting system includes a mold 1 and a pattern assembly 2 is supported within the mold and surrounded by an unbonded particulate material 3, such as sand. The molten alloy is introduced into the mold through a funnel 4 which communicates with inlet assembly 5 of pattern assembly 2.
  • Pattern assembly 2 includes a group of patterns ( corresponding in configuration to the part to be cast and which are formed of an evaporative foam material, such as expanded polystyrene.
  • the polystyrene, polymethylmethacrylate, or alternative pattern material may be coated with a synthetic resin or a pattern wax.
  • the construction of the evaporable foam resin casting system is not critical and may take any desired form.
  • Patterns 6 are supported from a central sprue 7 by a plurality of ingates 8 which can be formed of the same evaporable foam material as the patterns.
  • the sprue is generally rectangular in horizontal cross section having a central opening 9 and an open bottom.
  • Two vertical rows of ingates 8 are associated with each side surface of sprue 7 and each row of ingates is connected to one of the patterns 6, so that, as illustrated, eight patterns are supported from the sprue 7.
  • ingates 8 are formed integrally with the respective pattern 6, and the inner flat end of each ingate is attached to the respective surface of sprue 7 through a layer of adhesive 10.
  • the adhesive is a conventional type which will be vaporized by the heat of the molten alloy as it is introduced into the sprue and the vapor generated by vaporization of the adhesive will pass into the interstices of the sand.
  • ingates 8 alternately, can be integrally formed with sprue 7 and thus connected to the patterns 6 through use of a layer of adhesive, or the ingates can be separate pieces and connected through adhesives to both the patterns 6 and the sprue 7.
  • the upper end of each side surface of sprue 7 is provided with an opening or recess 11 through which sand can flow into the interior chamber 9 of the sprue.
  • opposite surfaces of the sprue are provided with openings 12 and 13, which also serve to admit sand to the internal chamber 9.
  • Inlet assembly 5 includes a generally rectangular inlet member 14 formed of an evaporable foam material, such as polystyrene, and having a closed bottom, as shown in Fig. 3.
  • the alloy to be used in the process of the invention is hypereutectic aluminum silicon alloy, such as that described in U.S. Patent 4,603,665.
  • the preferred alloy contains, by weight 16% to 19% silicon, 0.4 to 0.7% magnesium, up to 1.4% iron, up to 0.3% manganese, up to 0.37% copper, and the balance aluminum.
  • the magnesium acts to strengthen the alloy, while the iron and manganese tend to harden the alloy.
  • the resulting alloy has increased machineability, with more stable mechanical properties at elevated temperatures.
  • the copper content is maintained below 0.37% and preferably at a minimum. As the copper content is minimized, the aluminum-silicon-copper eutectic is correspondingly eliminated with the result that the alloy has a relatively narrow solidification range, below 150°F, and preferably less than 100°F.
  • the alloy has a yield strength of 15,000 to 30,000 psi, an ultimate tensile strength in the range of 20,000 to 35,000 psi, and an elongation of 0% to 2.0%.
  • Specific examples of the hypereutectic aluminum-silicon alloy to be used in the invention are as follows in weight percent:
  • the silicon in the alloy precipitates as relatively large crystals which generate substantial heat of crystallization.
  • the heat of crystallization generated by precipitation of the silicon crystals slows the solidification rate, by nonexternal means, while within the physical/thermodynamic constraints of nature. This allows additional time for the escape of vapors from the molten alloy, thereby minimizing gas porosity in the solidified alloy.
  • the choice of silicon is ideal for this purpose because silicon has the highest heat of fusion of any element in the periodic table.
  • the method of the invention permits relatively thin or complicated sections to be cast and also permits isolated areas of the pattern, located a relatively long distance from the ingate, to be cast without defects.
  • the solidification rate is slowed, not by increasing the initial pouring temperature of the alloy, but through the heat of crystallization generated by the precipitation of the silicon crystals.
  • the hypereutectic aluminum silicon alloy has a relatively low solidification range, less than 150°F, segregation on solidification is correspondingly minimized.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Continuous Casting (AREA)
  • Powder Metallurgy (AREA)
  • Manufacture Of Metal Powder And Suspensions Thereof (AREA)

Abstract

Le procédé de coulage décrit utilise un système à mousse évaporable avec un alliage d'aluminium et de silicium hypereutectique. L'alliage comprend 16 à 19 % en poids de silicium, 0,4 à 0,7 % en poids de magnésium, jusqu'à 1,4 % en poids de fer, jusqu'à 0,4 % en poids de manganèse et jusqu'à 0,37 % en poids de cuivre, le reste étant de l'aluminium. L'alliage en fusion est introduit dans un moule en contact avec une structure en mousse évaporable formée de polystyrène ou similaire. La chaleur de l'alliage en fusion provoque la décomposition et l'évaporation de la structure et la vapeur pénètre dans les interstices du sable environnant, pendant que l'alliage en fusion remplit le vide causé par l'évaporation de la structure. La chaleur de cristallisation produite par la précipitation du silicium lors de la solidification de l'alliage ralentit temporairement la vitesse de solidification de l'alliage, augmentant ainsi le temps disponible pour éliminer de l'alliage en fusion les vapeurs résiduelles de la structure.
PCT/US1988/002864 1987-09-08 1988-08-19 Systeme de coulage a mousse evaporable utilisant un alliage d'aluminium et de silicium hypereutectique WO1989002326A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
BR888807691A BR8807691A (pt) 1987-09-08 1988-08-19 Processo de fundicao
DE88907541T DE3885292T2 (de) 1987-09-08 1988-08-19 Vollformgiessverfahren zum giessen einer überentektischen aluminium-silicium-legierung.
AT88907541T ATE96352T1 (de) 1987-09-08 1988-08-19 Vollformgiessverfahren zum giessen einer ueberentektischen aluminium-silicium-legierung.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US9439387A 1987-09-08 1987-09-08
US094,393 1987-09-08

Publications (1)

Publication Number Publication Date
WO1989002326A1 true WO1989002326A1 (fr) 1989-03-23

Family

ID=22244899

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1988/002864 WO1989002326A1 (fr) 1987-09-08 1988-08-19 Systeme de coulage a mousse evaporable utilisant un alliage d'aluminium et de silicium hypereutectique

Country Status (6)

Country Link
EP (1) EP0377615B1 (fr)
JP (1) JPH03501229A (fr)
BR (1) BR8807691A (fr)
CA (1) CA1318106C (fr)
DE (1) DE3885292T2 (fr)
WO (1) WO1989002326A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5000244A (en) * 1989-12-04 1991-03-19 General Motors Corporation Lost foam casting of dual alloy engine block
DE19731804A1 (de) * 1997-07-24 1999-01-28 Bayerische Motoren Werke Ag Herstellverfahren für eine Zylinderbüchse einer Brennkraftmaschine
US9109271B2 (en) 2013-03-14 2015-08-18 Brunswick Corporation Nickel containing hypereutectic aluminum-silicon sand cast alloy
US9650699B1 (en) 2013-03-14 2017-05-16 Brunswick Corporation Nickel containing hypereutectic aluminum-silicon sand cast alloys
US10370742B2 (en) 2013-03-14 2019-08-06 Brunswick Corporation Hypereutectic aluminum-silicon cast alloys having unique microstructure

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4281705A (en) * 1978-03-14 1981-08-04 NOVEX Talalmanyfejleszto es Ertekesito Kulker. Rt. Process for casting objects having complicated shapes
US4603665A (en) * 1985-04-15 1986-08-05 Brunswick Corp. Hypereutectic aluminum-silicon casting alloy
US4632169A (en) * 1985-05-01 1986-12-30 Outboard Marine Corporation Two cycle cylinder block foam pattern

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4281705A (en) * 1978-03-14 1981-08-04 NOVEX Talalmanyfejleszto es Ertekesito Kulker. Rt. Process for casting objects having complicated shapes
US4603665A (en) * 1985-04-15 1986-08-05 Brunswick Corp. Hypereutectic aluminum-silicon casting alloy
US4632169A (en) * 1985-05-01 1986-12-30 Outboard Marine Corporation Two cycle cylinder block foam pattern

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5000244A (en) * 1989-12-04 1991-03-19 General Motors Corporation Lost foam casting of dual alloy engine block
EP0431770A2 (fr) * 1989-12-04 1991-06-12 General Motors Corporation Moulage à mousse perdue d'un bloc moteur en deux alliages
EP0431770A3 (en) * 1989-12-04 1992-10-21 General Motors Corporation Lost-foam casting of dual alloy engine block
DE19731804A1 (de) * 1997-07-24 1999-01-28 Bayerische Motoren Werke Ag Herstellverfahren für eine Zylinderbüchse einer Brennkraftmaschine
US9109271B2 (en) 2013-03-14 2015-08-18 Brunswick Corporation Nickel containing hypereutectic aluminum-silicon sand cast alloy
US9650699B1 (en) 2013-03-14 2017-05-16 Brunswick Corporation Nickel containing hypereutectic aluminum-silicon sand cast alloys
US10370742B2 (en) 2013-03-14 2019-08-06 Brunswick Corporation Hypereutectic aluminum-silicon cast alloys having unique microstructure

Also Published As

Publication number Publication date
CA1318106C (fr) 1993-05-25
BR8807691A (pt) 1990-08-07
DE3885292T2 (de) 1994-05-05
EP0377615B1 (fr) 1993-10-27
DE3885292D1 (de) 1993-12-02
JPH03501229A (ja) 1991-03-22
EP0377615A1 (fr) 1990-07-18

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