EP1900455A1 - Procédé de moulage à l'état semi solide et charge - Google Patents

Procédé de moulage à l'état semi solide et charge Download PDF

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Publication number
EP1900455A1
EP1900455A1 EP07013338A EP07013338A EP1900455A1 EP 1900455 A1 EP1900455 A1 EP 1900455A1 EP 07013338 A EP07013338 A EP 07013338A EP 07013338 A EP07013338 A EP 07013338A EP 1900455 A1 EP1900455 A1 EP 1900455A1
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EP
European Patent Office
Prior art keywords
alloy
solid
fraction
constituent
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.)
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Application number
EP07013338A
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German (de)
English (en)
Inventor
Adam E. Kopper
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.)
Brunswick Corp
Original Assignee
Brunswick Corp
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Filing date
Publication date
Application filed by Brunswick Corp filed Critical Brunswick Corp
Publication of EP1900455A1 publication Critical patent/EP1900455A1/fr
Withdrawn legal-status Critical Current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
    • B22D17/00—Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
    • B22D17/007—Semi-solid pressure die casting
    • 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
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C1/00—Making non-ferrous alloys
    • C22C1/12—Making non-ferrous alloys by processing in a semi-solid state, e.g. holding the alloy in the solid-liquid phase

Definitions

  • the invention relates to a slurry-on-demand (SOD) casting method according to the preamble of claim 1 and to a SOD casting alloy charge according to the preamble of claim 7.
  • SOD slurry-on-demand
  • the present invention relates in general to producing an "on-demand" semi-solid material for use in a casting process.
  • the prior art forming the starting point of the invention ( WO-A-O1/91945 ) incorporates electromagnetic stirring and various temperature control and cooling control techniques and apparatuses to facilitate the production of the semi-solid material within a comparatively short cycle time. Also included are structural arrangements and techniques to discharge the semi-solid material directly into a casting machine shot sleeve.
  • the concept of "on-demand” means that the semi-solid material goes directly to the casting step from the vessel where the material is produced.
  • the semi-solid material is typically referred to as a "slurry” and the slug which is produced as a “single shot” is also referred to as a billet.
  • Semi-solid forming of light metals for net-shape and near-net shape manufacturing can produce high strength, low porosity components with the economic cost advantages of die casting.
  • the viscosity of semi-solid metal is very sensitive to the slurry's temperature or the corresponding solid fraction.
  • the primary solid phase of the semi-solid metal should be nearly spherical.
  • semi-solid processing can be divided into two categories; thixocasting and rheocasting.
  • thixocasting the microstructure of the solidifying alloy is modified from dendritic to discrete degenerated dendrite before the alloy is cast into solid feedstock, which will then be re-melted to, a semi-solid state and cast into a mold to make the desired part.
  • rheocasting liquid metal is cooled to a semi-solid state while its microstructure is modified. The slurry is then formed or cast into a mold to produce the desired part or parts.
  • the major barrier in rheocasting is the difficulty to generate sufficient slurry within preferred temperature range in a short cycle time.
  • the cost of thixocasting is higher due to the additional casting and remelting steps, the implementation of thixocasting in industrial production has far exceeded rheocasting because semi-solid feedstock can be cast in large quantities in separate operations which can be remote in time and space from the reheating and forming steps.
  • a slurry is formed during solidification consisting of dendritic solid particles whose form is preserved.
  • dendritic particles nucleate and grow as equiaxed dendrites within the molten alloy in the early stages of slurry or semi-solid formation.
  • the dendritic particle branches grow larger and the dendrite arms have time to coarsen so that the primary and secondary dendrite arm spacing increases.
  • the dendrite arms come into contact and become fragmented to form degenerate dendritic particles.
  • the particles continue to coarsen and become more rounded and approach an ideal spherical shape.
  • the extent of rounding is controlled by the holding time selected for the process. With stirring, the point of "coherency" (the dendrites become a tangled structure) is not reached.
  • the semi-solid material comprised of fragmented, degenerate dendrite particles continues to deform at low shear forces.
  • the present invention incorporates apparatuses and methods in a novel and unobvious manner which utilize the metallurgical behavior of the alloy to create a suitable slurry within a comparatively short cycle time.
  • the semi-solid material is ready to be formed by injecting into a die-mold or some other forming process.
  • Primary aluminum (alpha) particle size is controlled in the process by limiting the slurry creation process to temperatures above the point at which solid alpha begins to form and alpha coarsening begins.
  • the stirring drives and controls a large volume and size of semi-solid slurry, depending on the application requirements.
  • the stirring helps to shorten the cycle time by controlling the cooling rate, and this is applicable to all type of alloys, i.e., casting alloys, wrought alloys, MMC, etc.
  • Vigorous electromagnetic stirring is the most widely used industrial process that permits the producation of a large volume of slurry. Importantly, this is applicable to any high-temperature alloys.
  • the other is termed “linear” stator stirring due to the up and down flow loop of the alloy within the vessel.
  • US-A-4,434,837 describes an electromagnetic stirring apparatus for the continuous making of thixotropic metal slurries in which a stator having a single two pole arrangement generates a non-zero rotating magnetic field which moves transversely of a longitudinal axis.
  • the moving magnetic field provides a magnetic stirring force directed tangentially to the metal container, which produces a shear rate of at least 50 /sec to break down the dendrites.
  • US-A-5,219,018 describes a method of producing thixotropic metallic products by continuous casting with polyphase current electromagnetic agitation. This method achieves the conversion of the dendrites into nodules by causing a refusion of the surface of these dendrites by a continuous transfer of the cold zone where they form towards a hotter zone.
  • the object of the present invention is to enable application of above explained SOD casting method to a wider area of die cast alloys and die casting applications.
  • vessel 10 contains a semi-solid casting alloy 12 and is carried on a fixture 14 on a transfer device such as robotic arm 16.
  • the alloy is heated, e.g. in a furnace as in the above prior art patents, to a molten liquid state, and then poured or discharged into vessel 10, which is surrounded by an optional cooling sleeve or jacket 18, and may be separated therefrom by air gaps such as 20 for controlled cooling.
  • Jacket 18 is disposed within an electromagnetic stirring device 22, e.g. a stator, supported by base plate 24 which may or may not be cooled.
  • electromagnetic stirring means specific reference is made to initially mentioned WO-A-01/91945 and further to EP-A-1 563 929 .
  • the alloy After cooling and magnetic stirring, the alloy is transferred while in a partial solid/liquid phase to a casting machine, all as is known and disclosed in the above noted and prior art patents.
  • the noted transfer may be facilitated by a pouring spout 26 formed in the upper collar or lip of vessel 10, Figs. 2, 3.
  • a SOD (slurry-on-demand) casting method casts a low-solid-fraction, namely 10 to 30% by weight solid-fraction alloy.
  • This is in contrast to prior solid-fraction ratios of 40 to 60%.
  • the noted prior 40 to 60% solid-fraction ratio provides an ice cream-like or jello-like billet
  • a 10 to 30% solid-fraction ratio provides a soupy milkshake-like or oatmeal-like charge or billet. It is has been found that the latter ratio, namely a low-solid-fraction, namely 10 to 30% solid-fraction, enables usage of a wider array of die cast alloys, including alloys 380, 383, 360, and Mercalloy (commercially produced under such Trademark by Mercury Marine Division, Brunswick Corporation).
  • the present method provides a slurry-on-demand casting method for casting a low-solid-fraction, namely 10 to 30% solid-fraction, alloy, including the steps of heating the alloy to a molten liquid state, e.g. in vessel 10 as above, cooling and stirring the alloy to nucleate and create a partial solid phase of the noted low-solid-fraction, and transferring the alloy while in the partial solid phase of the noted low-solid-fraction to a casting machine, as in the above noted prior art patents.
  • the alloy includes a pair of constituents of different melting point including a first constituent of a first melting point, and a second constituent of a second lower melting point.
  • the preferred embodiment of the present method cools the alloy below the first melting point but above the second melting point, whereafter the noted transferring step is performed.
  • the first and second melting points are preferably selected close enough to each other such that during the cooling and stirring step, the solidification of the first constituent is limited to the noted low-solid-fraction until the second constituent begins to solidify, and then the transferring step is performed when the temperature of the alloy is between the noted first and second melting points.
  • the alloy is provided with aluminum as the first constituent and silicon as the second constituent.
  • the silicon content in the molten state increases from 9% to 12% ⁇ 1% (in one preferred embodiment the latter being 12.6%) during the noted cooling step between the first and second melting temperatures whereby the amount of aluminum transitioning in phase from liquid to solid state is limited to the noted low-solid-fraction, wherein the eutectic composition of the alloy is at the noted 12.6% silicon.
  • the noted first constituent is nucleated and solidified by magnetic stirring, as in the above noted prior art patents, without introducing a foreign object into the molten alloy.
  • a rotating cooled rod e.g. a graphite rod
  • the alloy is transferred while in the molten liquid state to vessel 10, and then the cooling and magnetic stirring step is performed while the alloy is in vessel 10, and then the alloy is transferred in the noted partial solid phase of the noted low-solid-fraction from the vessel to the casting machine.
EP07013338A 2006-09-13 2007-07-07 Procédé de moulage à l'état semi solide et charge Withdrawn EP1900455A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US11/520,829 US20080060779A1 (en) 2006-09-13 2006-09-13 Sod, slurry-on-demand, casting method and charge

Publications (1)

Publication Number Publication Date
EP1900455A1 true EP1900455A1 (fr) 2008-03-19

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EP07013338A Withdrawn EP1900455A1 (fr) 2006-09-13 2007-07-07 Procédé de moulage à l'état semi solide et charge

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US (1) US20080060779A1 (fr)
EP (1) EP1900455A1 (fr)
JP (1) JP2008068321A (fr)
AU (1) AU2007216614A1 (fr)
CA (1) CA2587816A1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5032422B2 (ja) * 2008-09-11 2012-09-26 有限会社ティミス 電磁撹拌式鋳造方法とその装置
JP5965890B2 (ja) * 2013-12-16 2016-08-10 東芝機械株式会社 成形装置、半凝固金属の製造装置、成形方法及び半凝固金属の製造方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0663251A1 (fr) * 1994-01-13 1995-07-19 Rheo-Technology, Ltd Procédé pour le moulage sous pression de fonte à graphite à l'état de mélange solide-liquide
US20050161127A1 (en) * 1995-05-29 2005-07-28 Ube Industries, Ltd. Method for shaping semisolid metals
WO2006062482A1 (fr) * 2004-12-10 2006-06-15 Magnus Wessen Procede et dispositif de production d'une composition metallique liquide-solide

Family Cites Families (15)

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Publication number Priority date Publication date Assignee Title
US4049248A (en) * 1971-07-16 1977-09-20 A/S Ardal Og Sunndal Verk Dynamic vacuum treatment
US4434837A (en) * 1979-02-26 1984-03-06 International Telephone And Telegraph Corporation Process and apparatus for making thixotropic metal slurries
US4832112A (en) * 1985-10-03 1989-05-23 Howmet Corporation Method of forming a fine-grained equiaxed casting
US6845809B1 (en) * 1999-02-17 2005-01-25 Aemp Corporation Apparatus for and method of producing on-demand semi-solid material for castings
US6428636B2 (en) * 1999-07-26 2002-08-06 Alcan International, Ltd. Semi-solid concentration processing of metallic alloys
US6443216B1 (en) * 2000-06-01 2002-09-03 Aemp Corporation Thermal jacket for a vessel
US6402367B1 (en) * 2000-06-01 2002-06-11 Aemp Corporation Method and apparatus for magnetically stirring a thixotropic metal slurry
US6432160B1 (en) * 2000-06-01 2002-08-13 Aemp Corporation Method and apparatus for making a thixotropic metal slurry
US6399017B1 (en) * 2000-06-01 2002-06-04 Aemp Corporation Method and apparatus for containing and ejecting a thixotropic metal slurry
US7024342B1 (en) * 2000-07-01 2006-04-04 Mercury Marine Thermal flow simulation for casting/molding processes
US6611736B1 (en) * 2000-07-01 2003-08-26 Aemp Corporation Equal order method for fluid flow simulation
US6645323B2 (en) * 2000-09-21 2003-11-11 Massachusetts Institute Of Technology Metal alloy compositions and process
US6742567B2 (en) * 2001-08-17 2004-06-01 Brunswick Corporation Apparatus for and method of producing slurry material without stirring for application in semi-solid forming
JP2003068076A (ja) * 2001-08-27 2003-03-07 Elpida Memory Inc 半導体記憶装置の電力制御方法及び半導体記憶装置
US6918427B2 (en) * 2003-03-04 2005-07-19 Idraprince, Inc. Process and apparatus for preparing a metal alloy

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0663251A1 (fr) * 1994-01-13 1995-07-19 Rheo-Technology, Ltd Procédé pour le moulage sous pression de fonte à graphite à l'état de mélange solide-liquide
US20050161127A1 (en) * 1995-05-29 2005-07-28 Ube Industries, Ltd. Method for shaping semisolid metals
WO2006062482A1 (fr) * 2004-12-10 2006-06-15 Magnus Wessen Procede et dispositif de production d'une composition metallique liquide-solide

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Publication number Publication date
US20080060779A1 (en) 2008-03-13
CA2587816A1 (fr) 2008-03-13
JP2008068321A (ja) 2008-03-27
AU2007216614A1 (en) 2008-04-03

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