US20020084053A1 - Hot chamber die casting of semisolids - Google Patents

Hot chamber die casting of semisolids Download PDF

Info

Publication number
US20020084053A1
US20020084053A1 US10/086,393 US8639302A US2002084053A1 US 20020084053 A1 US20020084053 A1 US 20020084053A1 US 8639302 A US8639302 A US 8639302A US 2002084053 A1 US2002084053 A1 US 2002084053A1
Authority
US
United States
Prior art keywords
composition
die
hot
caster
semisolid
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.)
Abandoned
Application number
US10/086,393
Inventor
Merton Flemings
Sergio Gallo
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.)
Teksid SpA
Teksid Aluminum SRL
Original Assignee
Teksid Aluminum SRL
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
Priority to US09/228,965 priority Critical patent/US20010037868A1/en
Application filed by Teksid Aluminum SRL filed Critical Teksid Aluminum SRL
Priority to US10/086,393 priority patent/US20020084053A1/en
Publication of US20020084053A1 publication Critical patent/US20020084053A1/en
Assigned to TEKSID S.P.A. reassignment TEKSID S.P.A. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: GALLO, SERGIO
Assigned to TEKSID S.P.A. reassignment TEKSID S.P.A. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: FLEMINGS, MERTON C.
Assigned to TEKSID ALUMINIUM S.P.A. reassignment TEKSID ALUMINIUM S.P.A. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: TEKSID S.P.A.
Abandoned legal-status Critical Current

Links

Images

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22DCASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D17/00Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
    • B22D17/02Hot chamber machines, i.e. with heated press chamber in which metal is melted
    • B22D17/04Plunger machines
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22DCASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D17/00Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
    • B22D17/007Semi-solid pressure die casting

Abstract

A hot chamber method of die casting material in a semisolid state. The semisolid material has a high viscosity, which can be controlled by controlling the fraction of solid phase and the morphology of the solid phase. By controlling the viscosity of the melt, turbulence and consequent gas entrapment can be minimized or eliminated. Further, shrinkage is substantially reduced, thereby reducing porosity and hot tearing to form stronger, more reliable castings.

Description

  • This application is a continuation of and claims the priority of U.S. patent application Ser. No. 09/228,965, filed Jan. 12, 1999, the entire contents of which are incorporated by reference herein.[0001]
  • FIELD OF THE INVENTION
  • This application relates to methods and apparatus for hot chamber die casting of semisolid materials. [0002]
  • BACKGROUND OF THE INVENTION
  • Die casting has traditionally been divided into cold chamber processes and hot chamber processes. Hot chamber processes are distinguished by the fact that the injection cylinder is at least partially immersed in the molten metal, and thus is at the same temperature as the molten metal. Hot chamber die casting is widely used for light alloys such as magnesium- and zinc-based alloys, but has not been found to be commercially viable for casting aluminum alloys. These alloys generally have a higher melting temperature, and thus tend to rapidly degrade steel die casters using a hot chamber process. [0003]
  • Advantages of the hot chamber casting process include higher productivity, reduced scrap and metal losses, reduced die closing pressures, and reduced die wear. Both hot and cold chamber processes, however, suffer from the disadvantage that it is difficult to produce fully sound castings. Liquid metal generally enters the die in a turbulent fashion, entrapping mold gases and forming oxide inclusions in the finished part. Further, solidification shrinkage produces porosity and sometimes tears in the finished casting. It is an object of the present invention to provide a hot-chamber die casting system which minimizes or eliminates these disadvantages. [0004]
  • SUMMARY OF THE INVENTION
  • The present invention supplies a hot chamber method of die casting material in a semisolid state. The semisolid material has a high viscosity, which can be controlled by controlling the fraction of solid phase and the morphology of the solid phase. By controlling the viscosity of the melt, turbulence and consequent gas entrapment can be minimized or eliminated. Further, shrinkage is substantially reduced, thereby reducing porosity and hot tearing to form stronger, more reliable castings. [0005]
  • In one aspect, the invention provides a method of die casting, in which a semisolid composition is held between its liquidus and solidus temperatures, and agitated to prevent the formation of interconnected dendritic networks. The composition forms a slurry of solid particles in liquid, which is pumped into a die by an immersed pump. The material is then cooled to cast it in the die. The material may be, for example, a light alloy such as a magnesium, zinc, or aluminum alloy. [0006]
  • In another aspect, the invention includes a hot chamber die caster adapted to cast semisolid materials. The die caster includes a container for holding a composition in the semisolid state, and a pump for pumping the semisolid material into a die. Agitation means prevent the formation of dendrites, holding the material in a semisolid slurry state. The agitation means may be, for example, mechanical or electromagnetic. The caster may be used to cast a variety of light alloys, such as magnesium, zinc, and aluminum alloys. The pump may comprise ferrous materials such as stainless steel.[0007]
  • BRIEF DESCRIPTION OF THE DRAWING
  • The invention is described with reference to the several figures of the drawing, in which, [0008]
  • FIG. 1 is an illustration of a typical hot chamber die casting machine; [0009]
  • FIG. 2 is an illustration of one embodiment of a hot chamber die caster according to the invention; and [0010]
  • FIG. 3 is an illustration of another embodiment of a hot chamber die caster according to the invention. [0011]
  • DETAILED DESCRIPTION
  • FIG. 1 shows a typical hot chamber die caster [0012] 10, such as is commonly used for casting of magnesium and zinc alloys. The caster works on a “sump pump” principle, using an immersed piston 12 to force molten metal into the casting chamber 14.
  • A hydraulic cylinder [0013] 16 reciprocates the piston 12, within a piston chamber 17 whose end is connected to a gooseneck chamber 18 leading to the casting chamber 14. As the piston 12 reaches the top of its stroke, molten metal 20 flows into the piston chamber 17 and the gooseneck chamber 18 through an aperture 22. When the piston 12 then moves down into the chamber 18, it seals the aperture 22 and forces molten metal into the casting chamber 14. The casting chamber 14 is defined by two mold halves 24 and 26. Once the molten metal 20 in the casting chamber 14 has solidified, mold half 26 is moved to release the cast part. The mold is then closed and another cycle of the system can be performed. The gooseneck 18 and cylinder head 16 are thus continuously exposed to molten metal in this process.
  • The semisolid (or rheocasting) process was discovered about twenty years ago in the laboratory of one of the present inventors. It was found that mechanical stirring of a material between the liquidus and solidus temperatures could break up dendrites, forming a slurry of spheroidized solid particles in liquid. The viscosity of the material can be set to a value in the range of 10[0014] −1-108 poise, simply by controlling the stirring rate. Detailed descriptions of semisolid processing techniques can be found, for example, in U.S. Pat. Nos. 3,954,455 and 3,948,650 to Flemings, et al., both of which are incorporated herein by reference. Rheocast castings are generally of more uniform strength and of lower porosity than conventional castings.
  • The present invention uses semisolid processing to die cast materials using a hot chamber process. FIG. 2 shows a die caster designed to carry out this process. It is similar to the die caster shown in FIG. 1, but includes a mechanical stirrer [0015] 28 for agitating semimolten metal 21. In the embodiment shown, the furnace is provided with a cover 29 and a pressure inlet 30 to aid in forcing semimolten metal 21 through the aperture 22 into the piston chamber 17. Added pressure is not necessary in standard hot-chamber casting processes, because of the very low viscosity of fully molten metal (typically on the order of 10−2 poise). The higher viscosity of the semisolid compositions of the present invention may make applied pressure preferable or even essential, depending on the properties of the semisolid composition and of the caster material.
  • The optimum applied pressure for any given embodiment depends on the solid fraction of the semisolid metal and the speed with which it is desired to fully fill the piston chamber [0016] 17. It is preferred that die casters according to the invention be able to apply a pressure of at least 30 psi gauge (i.e., 30 psi above atmospheric pressure). If desired, applied pressure and the viscosity of the semisolid metal can be adjusted to provide a relatively high fill rate while minimizing the turbulence of flow into the casting chamber 14.
  • A temperature controller maintains the melt [0017] 20 within a relatively narrow temperature range, in order to ensure that it stays between the liquidus and solidus temperatures. For example, the liquidus and solidus temperatures differ by about 120° C. for Mg-8%Al-1%Zn, a common magnesium casting alloy. Known process-control techniques can be used to ensure that the metal temperature and viscosity are kept within acceptable limits.
  • FIG. 3 depicts an embodiment of the die caster related to that of FIG. 2, but using electromagnetic, rather than mechanical, stirring means. A set of coils [0018] 32 is provided for heating and stirring the semimolten metal 20. The use of electromagnetic stirring and heating may simplify the application of pressure, since the coils 32 do not need to be placed within the semimolten metal 21.
  • Hot chamber die casting of semisolid materials offers several advantages. The lower temperatures required may provide reduced energy costs and reduced wear rates for casters, and may expand the list of materials which can be inexpensively die cast by the hot chamber method. Further, the increased viscosity of the melt reduces turbulence as the melt enters the die. Reduced turbulence leads to minimal gas entrapment and thus to a reduced concentration of oxide inclusions. In addition, the shrinkage from the semisolid to the solid state is substantially less than that from the fully liquid to the solid state. Thus, shrinkage porosity and hot tearing are reduced in the present process, allowing simpler and less expensive mold designs to be used. [0019]
  • Other embodiments of the invention will be apparent to those skilled in the art from a consideration of the specification or practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the invention being indicated by the following claims.[0020]

Claims (12)

What is claimed is:
1. A method of die casting, comprising
holding a composition at a temperature between the liquidus temperature and the solidus temperature of the composition;
agitating the composition to form a slurry of primary solids comprising discrete solid particles in liquid while preventing the formation of interconnected solid dendritic networks;
pumping the composition into a die with a pump at least partially immersed in the composition; and
solidifying the material in the die.
2. The method of claim 1, wherein agitating is accomplished by mechanical stirring.
3. The method of claim 1, wherein agitating is accomplished by electromagnetic stirring.
4. The method of claim 1, wherein the composition comprises a majority component of a metal selected from the group consisting of magnesium, zinc, and aluminum.
5. The method of claim 4, wherein a surface of the pump in contact with the composition comprises a ferrous material.
6. The method of claim 1, further comprising applying a pressure greater than atmospheric pressure to the slurry.
7. A hot-chamber die caster, comprising:
a container for holding a semisolid composition between its liquidus and solidus temperatures;
means for agitating the semisolid composition to form a slurry of primary solids comprising discrete solid particles in liquid while preventing the formation of interconnected solid dendritic networks;
a die for casting the composition; and
a pump, at least partially immersed in the semisolid composition and arranged to pump the composition into the die.
8. The hot-chamber die caster of claim 7, wherein the agitation means comprise a mechanical agitator.
9. The hot-chamber die caster of claim 7, wherein the agitation means comprise an electromagnetic agitator.
10. The hot-chamber die caster of claim 7, wherein the caster is adapted to cast an alloy comprising a metal selected from the group consisting of aluminum, magnesium, and zinc.
11. The hot-chamber die caster of claim 11, wherein a surface of the pump in contact with the semisolid composition comprises a ferrous material.
12. The hot-chamber die caster of claim 7, further comprising a pressure inlet for applying a pressure greater than atmospheric pressure to the semisolid composition.
US10/086,393 1999-01-12 2002-02-28 Hot chamber die casting of semisolids Abandoned US20020084053A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US09/228,965 US20010037868A1 (en) 1999-01-12 1999-01-12 Hot chamber die casting of semisolids
US10/086,393 US20020084053A1 (en) 1999-01-12 2002-02-28 Hot chamber die casting of semisolids

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US10/086,393 US20020084053A1 (en) 1999-01-12 2002-02-28 Hot chamber die casting of semisolids
US10/306,947 US20030079854A1 (en) 1999-01-12 2002-11-29 Hot chamber die casting of semisolids

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
US09/228,965 Continuation US20010037868A1 (en) 1999-01-12 1999-01-12 Hot chamber die casting of semisolids

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US10/306,947 Continuation US20030079854A1 (en) 1999-01-12 2002-11-29 Hot chamber die casting of semisolids

Publications (1)

Publication Number Publication Date
US20020084053A1 true US20020084053A1 (en) 2002-07-04

Family

ID=22859280

Family Applications (3)

Application Number Title Priority Date Filing Date
US09/228,965 Abandoned US20010037868A1 (en) 1999-01-12 1999-01-12 Hot chamber die casting of semisolids
US10/086,393 Abandoned US20020084053A1 (en) 1999-01-12 2002-02-28 Hot chamber die casting of semisolids
US10/306,947 Abandoned US20030079854A1 (en) 1999-01-12 2002-11-29 Hot chamber die casting of semisolids

Family Applications Before (1)

Application Number Title Priority Date Filing Date
US09/228,965 Abandoned US20010037868A1 (en) 1999-01-12 1999-01-12 Hot chamber die casting of semisolids

Family Applications After (1)

Application Number Title Priority Date Filing Date
US10/306,947 Abandoned US20030079854A1 (en) 1999-01-12 2002-11-29 Hot chamber die casting of semisolids

Country Status (3)

Country Link
US (3) US20010037868A1 (en)
JP (1) JP2002534272A (en)
WO (1) WO2000041831A1 (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040043028A1 (en) * 2001-11-02 2004-03-04 Lee Chichang Methods and compositions for enhanced protein expression and/or growth of cultured cells using co-transcription of a Bcl2 encoding nucleic acid
US20040055726A1 (en) * 2002-09-25 2004-03-25 Chunpyo Hong Die casting method and apparatus for rheocasting
US20040055735A1 (en) * 2002-09-25 2004-03-25 Chun Pyo Hong Method and apparatus for manufacturing semi-solid metallic slurry
US20050011631A1 (en) * 2003-07-15 2005-01-20 Chun Hong Apparatus for manufacturing semi-solid metallic slurry
US20050126737A1 (en) * 2003-12-04 2005-06-16 Yurko James A. Process for casting a semi-solid metal alloy
WO2007139306A1 (en) * 2006-05-26 2007-12-06 Futurecast Co., Ltd. Hot chamber die casting apparatus for semi-solid metal alloy and the manufacturing method using the same

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6645323B2 (en) * 2000-09-21 2003-11-11 Massachusetts Institute Of Technology Metal alloy compositions and process
JP4175602B2 (en) * 2001-07-02 2008-11-05 セイコーアイデアセンター株式会社 Casting pouring equipment
DE10236794A1 (en) 2002-08-10 2004-02-26 Demag Ergotech Gmbh Casting metals comprises heating a solid metallic starting material in a container using an inductive heater above the solidus temperature, feeding to a storage vessel
AU2003294225A1 (en) * 2002-09-23 2004-04-23 Worcester Polytechnic Institute Method for making an alloy and alloy
US20040261970A1 (en) * 2003-06-27 2004-12-30 Cyco Systems Corporation Pty Ltd. Method and apparatus for producing components from metal and/or metal matrix composite materials
DE102009057197B3 (en) * 2009-11-30 2011-05-19 Oskar Frech Gmbh + Co. Kg Casting unit for a die casting machine
CN102806329A (en) * 2012-07-17 2012-12-05 南昌大学 Continuous blank casting system capable of performing semi-solid processing on non-ferrous alloy
KR101373758B1 (en) 2013-05-09 2014-03-13 해동이엠티(주) Appparatus for supplying melted magnesium
EP3585915A1 (en) 2017-02-24 2020-01-01 Innomaq 21, S.L. Method for the economic manufacture of light components

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3999593A (en) * 1976-02-19 1976-12-28 International Lead Zinc Research Organization, Inc. Method and apparatus for pore-free die casting
US4534403A (en) * 1980-10-14 1985-08-13 Harvill John I Hot chamber die casting machine
EP0733421B1 (en) * 1995-03-22 2000-09-06 Hitachi Metals, Ltd. Die casting method
JP3817786B2 (en) * 1995-09-01 2006-09-06 Tkj株式会社 Alloy product manufacturing method and apparatus

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040043028A1 (en) * 2001-11-02 2004-03-04 Lee Chichang Methods and compositions for enhanced protein expression and/or growth of cultured cells using co-transcription of a Bcl2 encoding nucleic acid
US20040055726A1 (en) * 2002-09-25 2004-03-25 Chunpyo Hong Die casting method and apparatus for rheocasting
US20040055735A1 (en) * 2002-09-25 2004-03-25 Chun Pyo Hong Method and apparatus for manufacturing semi-solid metallic slurry
EP1413373A2 (en) * 2002-09-25 2004-04-28 Hong Chunpyo Method and apparatus for pressure diecasting a semi-solid metallic slurry
EP1413373A3 (en) * 2002-09-25 2005-11-30 Hong Chunpyo Method and apparatus for pressure diecasting a semi-solid metallic slurry
US20050011631A1 (en) * 2003-07-15 2005-01-20 Chun Hong Apparatus for manufacturing semi-solid metallic slurry
US20050126737A1 (en) * 2003-12-04 2005-06-16 Yurko James A. Process for casting a semi-solid metal alloy
WO2007139306A1 (en) * 2006-05-26 2007-12-06 Futurecast Co., Ltd. Hot chamber die casting apparatus for semi-solid metal alloy and the manufacturing method using the same

Also Published As

Publication number Publication date
US20030079854A1 (en) 2003-05-01
JP2002534272A (en) 2002-10-15
US20010037868A1 (en) 2001-11-08
WO2000041831A1 (en) 2000-07-20

Similar Documents

Publication Publication Date Title
Nadella et al. Macrosegregation in direct-chill casting of aluminium alloys
Flemings Behavior of metal alloys in the semisolid state
Xia et al. Liquidus casting of a wrought aluminum alloy 2618 for thixoforming
Fan et al. Microstructure and mechanical properties of rheo-diecast (RDC) aluminium alloys
US4771818A (en) Process of shaping a metal alloy product
Eskin Broad prospects for commercial application of the ultrasonic (cavitation) melt treatment of light alloys
Ray Synthesis of cast metal matrix particulate composites
EP0462218B1 (en) Die-casting process and equipment
AU2001264749C1 (en) Method and apparatus for making a thixotropic metal slurry
Mohammed et al. Semisolid metal processing techniques for nondendritic feedstock production
Kiuchi et al. Mushy/semi-solid metal forming technology–Present and Future
US6645323B2 (en) Metal alloy compositions and process
US6070643A (en) High vacuum die casting
CN106555087B (en) A kind of 7 line aluminium alloy melting and casting methods
Zhang et al. Effect of pressure on microstructures and mechanical properties of Al-Cu-based alloy prepared by squeeze casting
Shabestari et al. Effect of copper and solidification conditions on the microstructure and mechanical properties of Al–Si–Mg alloys
EP1018383B1 (en) Die casting method
JP3474017B2 (en) Method for producing metal slurry for casting
Maleki et al. Effects of squeeze casting parameters on density, macrostructure and hardness of LM13 alloy
Zoqui et al. Macro-and microstructure analysis of SSM A356 produced by electromagnetic stirring
EP0575796B1 (en) Method for production of thixotropic magnesium alloys
KR100554093B1 (en) Forming apparatus for rheoforming method
EP0701002A1 (en) Process for moulding aluminium- or magnesiumalloys in semi-solidified state
CA2485828C (en) Process for injection molding semi-solid alloys
CN102482752B (en) Process for production of roughly shaped material for engine piston

Legal Events

Date Code Title Description
AS Assignment

Owner name: TEKSID S.P.A., ITALY

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:GALLO, SERGIO;REEL/FRAME:013354/0403

Effective date: 19990531

AS Assignment

Owner name: TEKSID S.P.A., ITALY

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:FLEMINGS, MERTON C.;REEL/FRAME:013369/0610

Effective date: 20021003

AS Assignment

Owner name: TEKSID ALUMINIUM S.P.A., ITALY

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:TEKSID S.P.A.;REEL/FRAME:013475/0979

Effective date: 20020531

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION