US3831662A - Casting mold with constricting device - Google Patents

Casting mold with constricting device Download PDF

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Publication number
US3831662A
US3831662A US00317522A US31752272A US3831662A US 3831662 A US3831662 A US 3831662A US 00317522 A US00317522 A US 00317522A US 31752272 A US31752272 A US 31752272A US 3831662 A US3831662 A US 3831662A
Authority
US
United States
Prior art keywords
casting
riser
cavity
metal
mold
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.)
Ceased
Application number
US00317522A
Other languages
English (en)
Inventor
J Nieman
R Worman
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.)
Caterpillar Inc
Original Assignee
Caterpillar Tractor Co
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 Caterpillar Tractor Co filed Critical Caterpillar Tractor Co
Priority to US00317522A priority Critical patent/US3831662A/en
Priority to GB5829173A priority patent/GB1457436A/en
Priority to GB2811776A priority patent/GB1457437A/en
Priority to DE2363940A priority patent/DE2363940A1/de
Priority to FR7346013A priority patent/FR2211304B1/fr
Priority to ES421688A priority patent/ES421688A1/es
Priority to JP49004440A priority patent/JPS4996923A/ja
Application granted granted Critical
Publication of US3831662A publication Critical patent/US3831662A/en
Priority to US06/194,535 priority patent/USRE31972E/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/08—Features with respect to supply of molten metal, e.g. ingates, circular gates, skim gates
    • B22C9/084—Breaker cores
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D31/00—Cutting-off surplus material, e.g. gates; Cleaning and working on castings

Definitions

  • ABSTRACT A stricture is formed between riser and cast article in a conventional metal mold casting process to facilitate clean removal of the riser after casting by interposing thin-walled frangible constriction means between riser cavity and casting cavity prior to pouring molten metal; the flow of metal into casting cavity is also regulated thereby.
  • This invention relates to metal foundry techniques.
  • this invention relates to techniques employed in metal founding to obtain a formed metal casting which requires a minimum amount of grinding or machining after being removed from the mold.
  • cast metal articles are made in the foundry industry by introducing molten metal into casting molds, and allowing the metal to cool and harden. Since the molten metal shrinks on cooling. resulting in an imperfect casting if further molten metal is not introduced to till the voids in the mold created by shrinkage, the industry conventionally employs risers, or molten metal reservoirs to supply molten metal to the filled mold required during the cooling process.
  • risers are normally provided with ports of fairly large cross-sectional area.
  • risers with such large port areas has, how ever, contributed its own problems. Although the absence of a constricting throat in these risers generally permits sufficient molten metal into the mold cavity during hardening to obviate the problem of shrinkage in the casting, the presence of the large cross-sectional area constitutes a strong connection between casting and riser when the liquid metal therein has cooled and hardened.
  • the riser is, of course, integrally cast with the casted article in the mold. and the riser must subsequently be separated from the casting. Such separation is frequently effected by, for example, sawing apart the two sections in the vicinity of the port between riser and casting; the casting must then be ground off to remove excess metal, and machined to obtain a smooth finish in the separation area.
  • the separation process is further complicated by the fact that often padding metal is included in the casting at the juncture of riser and casting; this excess metal is provided as a cushion" between the casting and the separation point in order to aid in preventing rupture of the casting itself when it is forcibly separated from the riser.
  • This padding metal must also be removed by grinding prior to machining.
  • Mold II conventionally includes a cope portion 12 fitted on a drag portion 13, with the juncture of these two parts indicated by line 14.
  • Molten metal is poured into the mold through a conventional type gating system 15 which includes a pouring basin 16, a downsprue l7, and a runner 18.
  • a choke is provided at the lower end of downsprue 17 to regulate the flow of metal therethrough. Molten metal flows through downsprue l7 and runner 18 to riser cavity 22, and from riser cavity 22 into adjoining casting cavity 24 through riser port 25. Casting cavity 24 will of course conform to the desired mold pattern.
  • the mold cavity 24, as illustrated, is defined by upper surface 26 disposed along juncture line 14, lower surface 27, and cylindrically shaped side surfaceor wall 28.
  • Riser port intersects casting cavity 24 preferably at one of the casting cavity surfaces having a lesser dimension, in this instance at side surface 28 having a height H determined by the vertical spacing between upper and lower surfaces 26 and 27, respectively.
  • the cross-sectional surface area of riser port 25 is generally rectangular, as shown in FIG. 3, and advantageously has a vertical dimension corresponding with height H of mold cavity 24.
  • constricting devicd 10 comprising outer peripheral rib 48 which is tapered on the inner surface thereof to form this wall 45.
  • the radius R between projections or flanges 42 of outer peripheral rib 48 is sufficiently large to provide a smooth transition to inlet side of wall to relieve stress concentrations therebetween which could otherwise be induced by high temperatures of the molten metal.
  • Rib 48 further contributes strength and rigidity to constricting device 10, reducing likelihood of breakage thereof during handling or casting.
  • Wall 45 is further provided with aperture 46 through which molten metal flows into mold cavity 24 indicated by mold cavity surfaces 26 and 27.
  • Aperture 46 is defined by rounded peripheral edge 47 of wall 45, whereby aperture 46 is narrowest in diameter approximately midway through wall 45.
  • Constricting device 10 is composed of a non-fusible material which will withstand high temperatures incountered in metal casting, and is preferably frangible to allow it to be readily broken away from the hardened metal casting. Many common fired ceramics will serve this purpose.
  • Wall 45 creates a stricture in the metal casting between the riser portion and cast article portion thereof, enabling the riser to be readily broken away from the cast article when the metal has cooled and hardened. It is necessary that wall 45 be sufficiently thin and have sufficient thermal conductivity to transmit a sufficient amount of heat to permit the proper directional solidification of a casting, and avoid premature blockage of the channel between riser and mold cavity with hardened metal.
  • wall 45 will depend on the relative thermal conductivity of the material comprising constriction device 10; however, it is preferable that device 10 be formed of a ceramic material, and in this case a wall thickness of about one-eighth inch will suffice. In general, wall thicknesses of from about onesixteenth inch to about one-fourth inch are contemplated.
  • Aperture 46 the sole connection between riser 22 and mold cavity 24, is proportioned relative to the size of choke 20 to control the flow of metal during pouring to permit the level of the molten metal in the riser cavity 22 to rise slightly above the aperture while the casting cavity is being filled. Impurities, such as slag and dross, normally floating on the surface of the metal are thus prevented from entering casting cavity 24.
  • Outlet wall 36 comprises the forward surface of mold cavity 24 and is contoured in the desired pattern to form this surface. Rib 48, including wall 45 thereof extends beyond the mold cavity opening, defined by surfaces 26 and 27, as indicated at sections 41 of rib 48. As is best seen in FIG. 3, inlet wall 35 is larger than riser port 25; riser port 25 in this instance has a height dimension equivalent to that of mold cavity 24.
  • a recess 43 is provided in the mold to receive constricting device 10.
  • the recess 43 is so located as to allow constricting device 10 to fit as tightly as possible between mold cavity 24 and riser port 25 to avoid leakage of molten metal therebetween which would require additional grinding or machining.
  • Constricting device 10 is firmly held in mold l] by the portions of rib 48 which extend into mold 11 (FIGS. 1 and 2). Constricting device 10 may be formed by any conventional means; however, die casting is frequently advantageous as it provides a greater degree of flexibility in obtaining configurations necessary to conform to the corresponding mold pattern surface.
  • mold 11 is conventionally formed by packing molding sand in the cope portion 12 and drag portion 13 about a pattern (not shown) which conforms to the shape of the desired casting.
  • the constricting device 10 is inserted into recess 43 when the mold is opened and the pattern removed.
  • recess 43 can be formed in the mold by any desired method, it is conveniently formed therein by a core print added to the casting pattern.
  • molten metal poured into pouring basin l6 flows down downsprue 17, into runner l8 and begins filling riser cavity 22.
  • the constricted aperture 46 permits the level of metal in the riser to rise above aperture 46 to prevent slag and dross floating on the surface of the metal from entering casting cavity 24 during the filling thereof.
  • wall 45 permits the transmission of heat from the metal in the riser to the adjacent metal in the casting to insure proper directional solidification of the casting.
  • mold 11 is usually placed on a mechanical shaker to remove the mold sand from around the metal.
  • the riser will normally be broken off from the casting by inertial forces due to the relatively small size of the structure between riser and casting.
  • device 10 will be fractured and crumbled from the casting as well. This eliminates the necessity of laboriously removing the riser by hand.
  • the casting is substantially free of superflouous metal normally found at the casting surface when the riser has been removed. Thus, the casting does not require any grinding or other preliminary operations performed on it prior to ma? chining.
  • a mold assembly for casting having an upper portion and a lower portion and a casting cavity defined by said upper and lower portions in which a casting is to be formed, said upper and lower portions mating along an interface plane, said casting cavity communicating with a riser cavity in which a riser is formed for feeding molten material to the casting cavity as the casting solidifies, means for forming a stricture between the riser cavity and casting cavity and for regulating the flow of molten metal from the riser cavity into the casting cavity, said means including a constriction device having aperture means therein, said device being interposed between the casting cavity and the riser cavity at the point of communication thereof, and said device simultaneously engaging both said upper and lower portion of said mold when said portions are in mating engagement along said interface plane.
  • constriction device comprises a frangible thinwalled member defin ing an aperture therethrough and further having a thickened ribbed peripheral portion.
  • said aperture means is of a size sufficient for inhibiting the flow of molten metal from the riser cavity into the casting cavity to maintain the level of molten metal within the riser cavity above said aperture means.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Molds, Cores, And Manufacturing Methods Thereof (AREA)
  • Casting Devices For Molds (AREA)
US00317522A 1972-12-22 1972-12-22 Casting mold with constricting device Ceased US3831662A (en)

Priority Applications (8)

Application Number Priority Date Filing Date Title
US00317522A US3831662A (en) 1972-12-22 1972-12-22 Casting mold with constricting device
GB5829173A GB1457436A (en) 1972-12-22 1973-12-17 Casting casting
GB2811776A GB1457437A (en) 1972-12-22 1973-12-17 Casting
DE2363940A DE2363940A1 (de) 1972-12-22 1973-12-20 Verfahren und form zur herstellung von metallgussteilen
FR7346013A FR2211304B1 (hu) 1972-12-22 1973-12-21
ES421688A ES421688A1 (es) 1972-12-22 1973-12-21 Perfeccionamientos introducidos en moldes para fundicion demetales.
JP49004440A JPS4996923A (hu) 1972-12-22 1973-12-22
US06/194,535 USRE31972E (en) 1972-12-22 1980-10-06 Casting mold with constricting device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US00317522A US3831662A (en) 1972-12-22 1972-12-22 Casting mold with constricting device

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US06/194,535 Reissue USRE31972E (en) 1972-12-22 1980-10-06 Casting mold with constricting device

Publications (1)

Publication Number Publication Date
US3831662A true US3831662A (en) 1974-08-27

Family

ID=23234056

Family Applications (1)

Application Number Title Priority Date Filing Date
US00317522A Ceased US3831662A (en) 1972-12-22 1972-12-22 Casting mold with constricting device

Country Status (6)

Country Link
US (1) US3831662A (hu)
JP (1) JPS4996923A (hu)
DE (1) DE2363940A1 (hu)
ES (1) ES421688A1 (hu)
FR (1) FR2211304B1 (hu)
GB (2) GB1457436A (hu)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1979000795A1 (en) * 1978-03-20 1979-10-18 Caterpillar Tractor Co Aperture forming member for gasifiable patterns
WO1999000202A1 (en) * 1997-06-26 1999-01-07 Georg Fischer Disa A/S Method and arrangement for casting metal objects in casting cavities adapted to be filled upwardly

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2905682A1 (de) * 1979-02-14 1980-08-21 Miguel Jeanneret Eingiessystem
GB2147531A (en) * 1983-10-07 1985-05-15 Mitsubishi Steel Mfg Facilitating the division of a feeder heat from an article cast in a mould
CH676094A5 (hu) * 1988-02-12 1990-12-14 Fischer Ag Georg
DE3872873T2 (de) * 1988-05-06 1993-03-04 Miguel Jeanneret Giesserei-anschnitt-system.
DK171732B1 (da) * 1996-05-01 1997-04-21 Georg Fischer Disa As Indretning af støbeindløbssystem med efterfødningsreservoir i en indløbskanal til efterfødning af støbegods samt fremgangsmåde til udformning af støbeindløbssystem
US9364890B2 (en) * 2013-03-11 2016-06-14 Ati Properties, Inc. Enhanced techniques for centrifugal casting of molten materials
CN104772430A (zh) * 2015-04-23 2015-07-15 江苏万力机械股份有限公司 铁型覆砂曲轴法兰工装

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US900970A (en) * 1906-03-15 1908-10-13 Edwin C Washburn Riser-lining for molding devices.
US1030066A (en) * 1911-10-17 1912-06-18 August Erlandson Pouring-gate for castings.
US1049877A (en) * 1912-09-06 1913-01-07 Herman H Lange Pattern for skim-gates.
US1657952A (en) * 1926-04-14 1928-01-31 Zoda Salvatore Skim gate
US2451505A (en) * 1945-05-21 1948-10-19 Edwin T Myskowski Screen for casting risers

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR913425A (fr) * 1942-01-21 1946-09-10 Meehanite Metal Corp Moule de fonderie à garniture intérieure et mode de production de pièces coulées

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US900970A (en) * 1906-03-15 1908-10-13 Edwin C Washburn Riser-lining for molding devices.
US1030066A (en) * 1911-10-17 1912-06-18 August Erlandson Pouring-gate for castings.
US1049877A (en) * 1912-09-06 1913-01-07 Herman H Lange Pattern for skim-gates.
US1657952A (en) * 1926-04-14 1928-01-31 Zoda Salvatore Skim gate
US2451505A (en) * 1945-05-21 1948-10-19 Edwin T Myskowski Screen for casting risers

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1979000795A1 (en) * 1978-03-20 1979-10-18 Caterpillar Tractor Co Aperture forming member for gasifiable patterns
WO1999000202A1 (en) * 1997-06-26 1999-01-07 Georg Fischer Disa A/S Method and arrangement for casting metal objects in casting cavities adapted to be filled upwardly
US6341640B1 (en) 1997-06-26 2002-01-29 Georg Fischer Disa A/S Method and arrangement for casting metal objects in casting cavities adapted to be filled upwardly

Also Published As

Publication number Publication date
JPS4996923A (hu) 1974-09-13
DE2363940A1 (de) 1974-06-27
GB1457437A (en) 1976-12-01
ES421688A1 (es) 1976-09-16
FR2211304A1 (hu) 1974-07-19
FR2211304B1 (hu) 1977-09-23
GB1457436A (en) 1976-12-01

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