EP0099470A1 - Coulée de métaux non-ferreux - Google Patents

Coulée de métaux non-ferreux Download PDF

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Publication number
EP0099470A1
EP0099470A1 EP83105779A EP83105779A EP0099470A1 EP 0099470 A1 EP0099470 A1 EP 0099470A1 EP 83105779 A EP83105779 A EP 83105779A EP 83105779 A EP83105779 A EP 83105779A EP 0099470 A1 EP0099470 A1 EP 0099470A1
Authority
EP
European Patent Office
Prior art keywords
sand
mould
casting
ferrous
resin
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.)
Withdrawn
Application number
EP83105779A
Other languages
German (de)
English (en)
Inventor
John Campbell
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.)
Cosworth Research and Development Ltd
Original Assignee
Cosworth Research and Development Ltd
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 Cosworth Research and Development Ltd filed Critical Cosworth Research and Development Ltd
Publication of EP0099470A1 publication Critical patent/EP0099470A1/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Withdrawn legal-status Critical Current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
    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C5/00—Machines or devices specially designed for dressing or handling the mould material so far as specially adapted for that purpose
    • B22C5/08—Machines or devices specially designed for dressing or handling the mould material so far as specially adapted for that purpose by sprinkling, cooling, or drying

Definitions

  • This invention relates to costing non-ferrous metals having a melting point below that of ferrous metals such as aluminium, magnesium and copper and alloys based thereon.
  • US-A-2,535,662 discloses the use of zircon sand for moulds for casting ferrous metals where linseed oil is the binder. The hardening of the linseed oil bonded sand is carried out in an oven. This process is costly in energy and is accepted throughout the industry as being at a grave disadvantage because of distortion during baking.
  • BE-A-864,207 discloses that zircon sand is used mainly because of its high refractoryness, i.e. it has high thermal stability and it does not fracture nor melt under conditions of thermal shock and so provides improved casting surface finishes relative to silica sands when casting ferrous metals.
  • moulds are produced by the Croning (Shell) process, which uses phenolic based thermo-setting resins. Although the process has a reasonable reputation for the accuracy of the resulting castings, the accuracy is necessarily limited by the use of hot metal patterns, which are subject to thermal distortion and the distortion of the thin shell moulds.
  • the expensive zircon sand is re-ciaimed by a number of existing thermal reclamation systems, most of which heat the sand to a temperature in the range 800°C to I,000°C to burn off the remaining resin prior to re-coating with fresh resin.
  • the high cost of such reclamation is usually recoverable in the relatively high price of such ferrous shell-moulded castings.
  • a method of casting non-ferrous metals having a melting point below that of ferrous metals comprising the steps of making a mould predominantly of zircon sand and a chemically hardenable organic resin binder which can be hardened at a temperature not exceeding 50°C, casting molten non-ferrous metal into said mould to make a casting and separating the used sand from the casting.
  • the mould and cores may comprise, in addition to a catalyst or hardening agent for the resin binder;
  • the organic resin binder is preferably a resin which can be hardened at or substantially at room temperature.
  • the organic resin binder may comprise phenolic, furane, or isocyanate base resin which can be hardened by a solid or liquid catalyst but which is preferably gas hardened.
  • Zircon sand preferably comprises the whole of the sand of which the mould and cores, if any, are made.
  • the zircon sand may have a particle grain size lying in the range 50pm to 500 ⁇ m. An average grain size of approximately 100 ⁇ m is common but as low as 75 ⁇ m is experienced.
  • the mouid, and core if any, may be made by hand filling and ramming or by blowing on an automatic core or mould blowing machine.
  • a mould a moulding box or a boxless process may be used.
  • the method includes the steps of returning the sand to grain size and reclaiming the separated used sand such as by the method described hereinafter, which method and apparatus are the subject of our U.K. Application No. 8137797, and then using the thus reclaimed sand to make a mould in which molten non-ferrous metal is cast to make a casting followed by separating the used sand from the casting, again reclaiming the sand by the above described method and re-using the reclaimed sand to make a further mould.
  • zircon sand for complete moulds and cores for non-ferrous metals is not an obvious choice, indeed the cost of zircon and the cost of reclaiming zircon blocked the concept of its use in this way until the present invention.
  • the present invention provides a number of extremely important and unlooked for benefits as follows.
  • the accuracy of cored holes and wall thicknesses defined by cores are improved by a factor of up to twenty times. External features of castings are typically five times more accurate than their silica sand cast counterparts. This improvement in accuracy follows from the low expansion combined with the high thermal capacity of zircon sand compared to silica. It enables the accuracy to exceed the accuracy of all other casting methods known to date including investment and pressure die casting. The high thermal capacity increases freezing rate and also improves mechanical properties.
  • the levels of addition of the resin binder are significantly lower than those used for the Croning Shell Process. Because the patterns are used at or near to room temperature, they retain their accuracy and so produce accurate moulds and cores. Also, the moulds can be made of any convenient thickness as a thick shell, or in the form of block moulds, or can be made in steel boxes or frames. In this way, also, accuracy can be conserved compared and contrasted for example with a thin Croning Shell mould which is easily distorted.
  • the zircon sand is reclaimed by maintaining a mass of the sand without agitation of sand in the container whilst permitting the gas to percolate through the sand and whilst the sand is held in a treatment teperature range of 250°C to below 600°C for a time to achieve good reclamation.
  • the treatment temperature may lie in the range 250 0 C to 400°C, preferably in the range 250°C to 350°C.
  • the treatment temperature may lie in the range 300°C to below 400° C .
  • the treatment temperature lies in the range 300°C to 350°C.
  • the treatment time may lie in the range 4-30 hours and may lie in the range 4-24 hours.
  • the mass of sand being treated may lie in the range 20 to 100 tons.
  • a foundry includes a moulding station 1 where moulds are made of zircon sand bonded with a furane resin.
  • the moulds may be made by hand filling or ramming but, in the present example, are blown using an automatic mould blowing machine.
  • the mould may be used in conventional mould boxes or a boxless process, as in the present example, may be used.
  • a phenolic resin, isocyanate or similar resin which can be hardened by soiid or liquid catalyst but which is preferably gas hardened at room temperature or up to 50 0 C may be used.
  • a core or cores are similarly made of such resin bonded zircon sand, although if desired a different binder system may be used compared with that of the remainder of the mouid.
  • the core or cores is/are positioned, as necessary, within the mould cavity at a mould assembly station 2 where the cope and drag halves of the mould are closed.
  • the mould comprises:
  • the resin was hardened using SO 2 gas amounting to about 0.25% S0 2 equivalent by weight of sand.
  • the sand has average grain size of 145 ⁇ m.
  • moulds are transferred by a conveyer 3 to a casting station 4 where molten metai, in the present example magnesium alloy, is cast through ingates in the mould into the mould cavity and around the core or cores when present.
  • molten metai in the present example magnesium alloy
  • the full mould is transferred by the conveyor 3 to a shakeout station 5 where the sand of the mould and core or cores, when present, are shaken out of the casting by a shakeout machine.
  • the used lumps of zircon sand initially shaken out of the casting are returned to grain size by the vibratory action of the shakeout machine at the shakeout station 5.
  • the sand lumps can be returned to grain size by a separate attrition or crushing unit, not shown.
  • the sand, returned to grain size, is fed by a conveyor 6 to a sand reclaiming plant 7 where the sand is reclaimed and then supplied by a conveyor 8 to the moulding station I where binder is mixed with the reclaimed sand and new cope and drag parts of a mould made and transferred to the mould assembly station 2.
  • the reclaiming plant 7 comprises, referring to Figure 2, a closed hopper 10 to which sand is supplied by the conveyor 6. Sand is fed from the bottom of the hopper 10 by a screw conveyor I into a container 12 containing electrical heating element 13 and sparge tubes 14. Fluidising air is fed to the sparge tubes 14 via a duct 15 by a fan 16.
  • Sand is heated to a temperature lying in the range 250-400°C to the fluidised bed. As a result, little or no reclamation occurs in the fluidised bed. However, if desired the sand may be heated to a higher temperature, for example up to 600°C in which case some reclamation of the sand occurs in the fiuidised bed, the extent of reclamation depending upon the dwell time of the sand in the bed.
  • the temperature of the sand entering the container 17 is only slightly below the temperature in the fluid bed. If it is necessary to feed the sand over a greater distance, for example as a result of location of the container 12 remote from the container 17, suitable thermal insulation and/or auxiliary heating means may be necessary to prevent excessive cooling of the sand.
  • the sand is allowed to dwell unagitated in the container 17 at a temperature lying in the range 250-400°C, although the maximum temperature may be 600°C, for a time sufficient to achieve reclamation.
  • oxygen for the slow combustion process occurring within the container 17 is obtained from air rising from the exit 19 and percolating through the mass of sand 18 in the container 17, the dwell time typically lies in the period four to twenty four hours.
  • air may be caused to pass through the sand at a flow rate of at least 400/L/min m 2 in which case the dwell time is measured in minutes.
  • the used air is removed from the container 17 by an updraught through a conduit 20, extending to a cyclone 21 where the extracted dust fines and the like are withdrawn as indicated at 22 whilst invisible fumes are discharged to atmosphere as indicated at 23.
  • the table below sets out the operating conditions in respect of two reclaiming operations carried out on zircon sand which has been used to manufacture non-ferrous metal castings. After treatment under conditions set out in the table, the sand was re-used and found to produce high quality moulds in which non-ferrous metals again cast.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Mold Materials And Core Materials (AREA)
  • Molds, Cores, And Manufacturing Methods Thereof (AREA)
EP83105779A 1982-06-18 1983-06-13 Coulée de métaux non-ferreux Withdrawn EP0099470A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8217743 1982-06-18
GB8217743 1982-06-18

Publications (1)

Publication Number Publication Date
EP0099470A1 true EP0099470A1 (fr) 1984-02-01

Family

ID=10531147

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83105779A Withdrawn EP0099470A1 (fr) 1982-06-18 1983-06-13 Coulée de métaux non-ferreux

Country Status (5)

Country Link
EP (1) EP0099470A1 (fr)
JP (1) JPS597457A (fr)
AU (1) AU1577283A (fr)
GB (1) GB2122523B (fr)
ZA (1) ZA834310B (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1992015181A1 (fr) * 1991-02-22 1992-09-03 SAMUEL STRAPPING SYSTEMS_(a division of Samuel Manu-Tech Inc Lit fluidifie et procede de traitement de materiaux
WO2003013760A2 (fr) * 2001-08-07 2003-02-20 Noram Technology, Ltd Produits de fabrication de moules et de noyaux utilises pour le coulage de metaux, et leur procedee fabrication et de recyclage a partir de roche concassee
CN102051507A (zh) * 2009-11-04 2011-05-11 株式会社亚铝质提 耐热镁合金及合金铸件的制造方法

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61290151A (ja) * 1985-06-14 1986-12-20 株式会社クボタ 屋根材
CH681434A5 (fr) * 1990-01-31 1993-03-31 Fischer Ag Georg

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1886249A (en) * 1930-10-04 1932-11-01 Lebanon Steel Foundry Mold for high temperature castings
US2535662A (en) * 1948-03-10 1950-12-26 Gen Electric Mold for casting metals
US3179990A (en) * 1961-10-26 1965-04-27 Freeman Chemical Corp Foundry composition with cross-linked polyester binder
US3212144A (en) * 1962-06-22 1965-10-19 Frank R Capps Sand molds for metal casting and methods therefor
BE864207A (fr) * 1978-02-22 1978-08-22 Du Pont Sable de moulage contenant du zircon
EP0054288A1 (fr) * 1980-12-16 1982-06-23 Cosworth Research And Development Limited Procédé et dispositif de traitement d'un matériau granuleux

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1115441A (en) * 1965-01-19 1968-05-29 Doulton & Co Ltd Improvements relating to the production of metal and alloy castings
GB1413779A (en) * 1974-05-24 1975-11-12 Tsniitmash Self-hardening moulding mixture of making foundry moulds and cores
GB1568519A (en) * 1976-12-21 1980-05-29 Foseco Technik Ag Resin-forming furfuryl alcohol compositions and their use in the production of foundry moulds and cores
GB1533357A (en) * 1977-04-13 1978-11-22 Ts Ni I T Mastiinostr Process for preparing a sand composition for use in making cores and moulds
AU539985B2 (en) * 1979-10-01 1984-10-25 Farley Metals Inc. Die casting core

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1886249A (en) * 1930-10-04 1932-11-01 Lebanon Steel Foundry Mold for high temperature castings
US2535662A (en) * 1948-03-10 1950-12-26 Gen Electric Mold for casting metals
US3179990A (en) * 1961-10-26 1965-04-27 Freeman Chemical Corp Foundry composition with cross-linked polyester binder
US3212144A (en) * 1962-06-22 1965-10-19 Frank R Capps Sand molds for metal casting and methods therefor
BE864207A (fr) * 1978-02-22 1978-08-22 Du Pont Sable de moulage contenant du zircon
EP0054288A1 (fr) * 1980-12-16 1982-06-23 Cosworth Research And Development Limited Procédé et dispositif de traitement d'un matériau granuleux

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1992015181A1 (fr) * 1991-02-22 1992-09-03 SAMUEL STRAPPING SYSTEMS_(a division of Samuel Manu-Tech Inc Lit fluidifie et procede de traitement de materiaux
WO2003013760A2 (fr) * 2001-08-07 2003-02-20 Noram Technology, Ltd Produits de fabrication de moules et de noyaux utilises pour le coulage de metaux, et leur procedee fabrication et de recyclage a partir de roche concassee
WO2003013760A3 (fr) * 2001-08-07 2003-10-23 Noram Technology Ltd Produits de fabrication de moules et de noyaux utilises pour le coulage de metaux, et leur procedee fabrication et de recyclage a partir de roche concassee
US6691765B2 (en) 2001-08-07 2004-02-17 Noram Technology, Ltd. Products for the manufacture of molds and cores used in metal casting and a method for their manufacture and recycle from crushed rock
CN102051507A (zh) * 2009-11-04 2011-05-11 株式会社亚铝质提 耐热镁合金及合金铸件的制造方法

Also Published As

Publication number Publication date
ZA834310B (en) 1984-07-25
AU1577283A (en) 1983-12-22
JPS597457A (ja) 1984-01-14
GB8316242D0 (en) 1983-07-20
GB2122523B (en) 1986-01-29
GB2122523A (en) 1984-01-18

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Inventor name: CAMPBELL, JOHN