US3750442A - Compressive forming - Google Patents

Compressive forming Download PDF

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Publication number
US3750442A
US3750442A US00245734A US3750442DA US3750442A US 3750442 A US3750442 A US 3750442A US 00245734 A US00245734 A US 00245734A US 3750442D A US3750442D A US 3750442DA US 3750442 A US3750442 A US 3750442A
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United States
Prior art keywords
workpiece
die cavity
matrix
die
article
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Expired - Lifetime
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US00245734A
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English (en)
Inventor
R Cogan
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General Electric Co
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General Electric Co
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Publication date
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21K—MAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES, RIVETS, BOLTS OR WHEELS
    • B21K1/00—Making machine elements
    • B21K1/28—Making machine elements wheels; discs
    • B21K1/32—Making machine elements wheels; discs discs, e.g. disc wheels
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
    • B21J5/00—Methods for forging, hammering, or pressing; Special equipment or accessories therefor

Definitions

  • a die including a. a die cavity, b. a workpiece receiving chamber connected with and angularly disposed with the die cavity and c. port means in a wall of the die cavity and distinct from the workpiece receiving chamber; a soft metal matrix contained within the die cavity; means to introduce a workpiece into the die cavity; force means to press the workpiece into the die cavity; and control means to control the rate of release of matrix from the die cavity through the port means.
  • This invention relates to the forming of articles through the use of compressive forces, and more particularly, to methods and apparatus for use in the compressivc forming of solid metallic articles.
  • 1,613,595 Abel shows the forging of a blank into an article through the use of appropriately shaped dies into which the blank is pressed.
  • a compressive force sometimes transmitted to the workpiece through a liquid is applied inside a hollow work piece to press portions of the workpiece into a die member.
  • the die may or may not include a type of guiding means to adjust the shape of the expanding wall.
  • various drop forging and roll forming methods are widely described in the literature. In all of these known methods and with the use of known machining and grinding, are required; In addition, the
  • Another object is to provide an improved apparatus, including a die cavity in which a workpiece is formed and in which the application of back pressure to the deforming portion of a workpiece can be controlled and programmed.
  • FIGS. 1 3 are sectional, partially schematic views of one form of the die of the present invention in operation
  • FIGS. 4 and 5 are sectional, partially schematic views of another form of the die of the present invention in operation
  • FIGS. 6, 7 and 8 are sectional, isometric, partially schematic views of other forms of the apparatus of the present invention.
  • FIGS. 9, l0 and 11 are sectional, partially schematic views of still another form of the present invention.
  • FIG. 12 is sectional, isometric view ofa whwlformed by the apparatus in FIGS. 9 11.
  • the rate of matrix flow from the die cavity is controlled so that a reaction force is applied to the deforming workpiece at the interface between the matrix and the workpiece of a magnitude of at least threequarters of the compressive strength of the material of the workpiece.
  • the apparatus form of the present invention in one aspect includes a die having a die cavity. Connected with the die cavity are a workpiece'receiving chamber and port means.
  • the apparatus includes means to introducea matrix into the die cavity and means to intro- ,duce a workpiece into the die cavity, force means to press the workpiece intothe die cavity, and control means to control the rate of matrix release from media cavitythrough the port means.
  • the practice of the'present invention will eliminate the hot forming and cladding required to be used with many advanced materials. It will allow cold forming of highly reactive materials such as those reactive to oxidation and to conventional forging temperatures.
  • such materials as beryllium, tungsten, columbium and molybdenum could be cold formed in the M clad condition.
  • brittle alloys such as the nickel base superalloys, cast iron, etc., which are now used only in the cast condition becauseof their relatively poor ductility have been worked by the method of the present invention to result in superior strength as a result of the improved grain size and flow characteristics developed by the present invention.
  • This method is applicable as well to conventional, more ductile alloys to prepare in a single operation more complex forging shapes than can be prepared by present processing thus eliminating finishing operations and costs.
  • FIGS. 1 3, inclusive represent a sequence using the apparatusof this invention, in the practice of its method aspect, to form a billet 20, FIG. 1 into a shaped disc 20a in FIG. 3.
  • a die 24 having a cavity 26 shaped according to the article to be compressively formed is first filled with a matrix 28.
  • the material of matrix 28 is one which has a compressive strength less than that of the material of billet 20. Compressive strength is defined, with regard to yield, as the maximum stress that a material subjectcd to compression can withstand without a predefined amount of plastic deformation. Therefore, the material of matrix 28 will flow at a pressure lower per unit than will the material of billet 20.
  • Die 24 is provided with release or port means 30 through which the matrix 28 can flow.
  • Port means 30 can be of a predetermined size or can include valve means, such as 42 in FIG. 6, to control the rate of flow of matrix 28.
  • This arrangement provides a predetermined pressure inside cavity 26, particularly at interface 32 between the workpiece billet and the matrix 28.
  • the size and shape of cavity 26 can be maintained uniformly throughout the process either by means of externally applied force such as is represented by arrows 34, or by the construction and resistance to deformation of the material of the die itself in comparison with the magnitude of the forces applied inside the die during processing.
  • a workpiece deforming force represented by arrow 36 is applied to the workpiece billet 20 to press the workpiece into the die.
  • the minimum amount required for force 36 is the sum of l) a force equal to the compressive strength of the material of billet 20 under ordinary yield conditions, (2) a force predetermined to press matrix 28 through port 30 and (3) a friction force resisting flow of the workpiece in the die. It has been found that the application of back pressure on the deforming interface 32 of workpiece 20 by a matrix 28 preloaded into the die cavity inhibits the start of cracking of the workpiece material at that interface and allows a much greater deformation of workpiece 20 than could be achieved under normal extrusion type conditions.
  • the preferred amount of back pressure exerted by the matrix on workpiece 20 is at least about three-quarters of the compressive strength of the workpiece material.
  • FIGS. 4 and 5 the operation and apparatus in FIGS. 1 3 can be modified according to this invention to provide the application of force 36 to workpiece 20 from a plurality of directions in order to control the flow of workpiece material.
  • the matrix 28 is controlled and released in the same manner as described in connection with FIGS. 1 3.
  • a plurality of ports 30 can be appropriately located in die 40 to guide further the flow of the workpiece material by means of the release of matrix 28 from the die cavity 26.
  • a manifold 38 can be provided with die 40, as in FIG. 6, to control back pressure while allowing ports 30 to control flow rates.
  • Means to control theflow of matrix from manifold 38 can be provided by one or a plurality of ports 30a which can include valves 42 in the ports or in con nection with manifold -38 to control ultimately the back pressure applied to interface 32 of workpiece material 20. Programming the passage of matrix 28 through a plurality of valves 42 can provide accurate control of workpiece material flow.
  • FIGS. 7 and 8 represent anotherform of the present invention using split die halves 44 and 44a held together by external forces 46 such as a mechanical press.
  • External force 46 cooperates with and is less than workpiece deforming force 36 per unit of area.
  • the dies 44 and 44a Upon application of force 36, the dies 44 and 44a will separate to create aport means 48 to allow matrix 28 to be extruded or released.
  • port 48 is an annular slot.
  • the relationship of workpiece deforming force 36 to force 46 determines the separation distance between die halves 44 and 44a and hence the size of port 48.
  • the present invention can be used to make a wheel for an axial flow compressor stage having a central opening for mounting the wheel on a shaft.
  • a wheel is shown in FIG. 12.
  • a ring forging 50 in FIG. 9 can be used with the method. and apparatus of this invention shown in FIGS. 9, l0 and 11 in the manner described above.
  • the workpiece material 50 of each portion of the ring is deformed in two directions at the same time with the matrix being released through a plurality of ports such as 52 and 54.
  • FIGS. 4 and 5 involving the application of force from ,a plurality of di-. rections to each portion of the workpiece can be applied to the operations of FIGS. 9, l0 and 11 within the scope of this invention to form an article such as shown in FIG. 12.
  • the matrix material preloaded into and cooperating with the die cavity is a material more ductile or having a lower compressive strength than that of the material of the workpiece and of the material of the die.
  • a ductile matrix material is preferably based on such elements as lead, copper, zinc and other soft, easily ex truded materials.
  • less ductile materials can be used provided the die material can withstand the total compressive forces required through the use of a matrix more difficult to flow.
  • the matrix material which fills the die cavity prior to operation can be introduced in a variety of ways. However successful operation has resulted by forcing a matrix such as lead, under substantial pressure into the cavity by a ram through the workpiece receiving port until the cavity is filled. Then the workpiece material is placed in the workpiece receiving cavity in contact with the matrix and the above described process of pressing the workpiece material into the die takes place with the more ductile matrix being displaced by the workpiece flowing into the die cavity.
  • the back pressure exerted by the matrix depends upon the matrix material used, the rate at which the matrix was displaced, and the size and shape of the port or the control exercised by the valve in connection with the port.
  • the back pressure sometimes referred to as hydro dynamic pressure, can be controlled by these variablesto suit the requirements of the workpiece material and the shape of the article being formed.
  • ductile tensile fractures begin with the formation of extremely small voids, concurrent with plastic slip.
  • the present invention supplies forces by back pressure to effectively prevent these voids from forming or opening.
  • the back pressure applied by the matrix results in uniform strain distribution in the compressively formed article.
  • the non-uniform strain distribution arising from die friction results in a complex distribution of stresses in the article from its center to its edge. Such a distribution can lead to cracking at the edges because of the development of high-tensile hoop stresses.
  • the low yield stress of the matrix as used in the present invention limits the effect offriction and produces a more homogeneous distribution eliminating cracking by controlling the strain rate of the workpiece material.
  • Apparatus for the compressive forming of an article comprising:
  • a die including a. a die cavity
  • a workpiece receiving chamber connected with and angularly disposed with the die cavity and c. port means in a wall of the die cavity and distinct from the workpiece receiving chamber;
  • control means to control the rate of release of matrix from the die cavity through the port means.
  • Apparatus for use in the compressive forming of an article comprising:
  • a die including a. a plurality of shaped members which together define walls of a die cavity and b. a workpiece receiving chamber connected with and angularly disposed with the die cavity;
  • the first force means being greater than the sum of the second force means and the compressive strength of the workpiece material
  • the first force means deforms the workpiece into the die cavity while at the same time separating the walls of the plurality of shaped members to allow matrix to flow from the walls of the die cavity.
  • a method for compressively forming a workpiece into an article in a die having a cavity shaped as the article to be formed comprising the steps of:
  • the matrix being released at a controlled rate to control pressure exerted at the interface between the workpiece and the matrix to at least about threefourths of the compressive strength of the workpiece.
  • a method for compressively forming a workpiece into an article in a die having a workpiece receiving chamber and a die cavity shaped as the article to be formed comprising the steps of:
  • the matrix being released at a controlled rate to control pressure exerted at the interface between the matrix and the workpiece to at least about threefourths of the compressive strength of the workpiece.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Forging (AREA)
US00245734A 1962-12-19 1962-12-19 Compressive forming Expired - Lifetime US3750442A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US24573462A 1962-12-19 1962-12-19

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US3750442A true US3750442A (en) 1973-08-07

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US (1) US3750442A (de)
CH (1) CH414321A (de)
GB (1) GB999228A (de)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4356612A (en) * 1980-03-31 1982-11-02 Cameron Iron Works, Inc. Method of producing a forged product
US4422236A (en) * 1981-10-01 1983-12-27 General Electric Company Method of extruding parts with captured fixture
US5934876A (en) * 1997-10-21 1999-08-10 Beckett Air Incorporated Blower wheel assembly with steel hub having cold-headed lugs, and method of making same
US6179566B1 (en) 1997-10-21 2001-01-30 Beckett Air Incorporated Blower Wheel assembly with steel hub, and method of making same
US6206640B1 (en) 1997-10-21 2001-03-27 Beckett Air Incorporated Blower wheel assembly with steel hub, and method of making same
US6220818B1 (en) 1997-10-21 2001-04-24 Beckett Air Incorporated Blower wheel assembly with steel hub, and method of making same
US7895873B1 (en) * 2008-04-23 2011-03-01 Meadville Forging Co LP Method and system for simultaneously forging two parts
US20110113850A1 (en) * 2008-01-03 2011-05-19 General Electric Company Near net shape forging process for compressor and turbine wheels and turbine spacer wheels

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2139164C1 (ru) * 1998-05-12 1999-10-10 Уфимский государственный авиационный технический университет Способ деформирования заготовок в пересекающихся каналах

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1012401A (en) * 1907-09-03 1911-12-19 Piercy B Mccullough Dental swaging apparatus.
US1613595A (en) * 1925-01-21 1927-01-11 Patent Button Co Method of making metal articles
US2168641A (en) * 1938-03-07 1939-08-08 Northern Indiana Brass Co Die mechanism
US2783727A (en) * 1951-09-12 1957-03-05 Lake Erie Engineering Corp Cushion die structure for apparatus for pressing sheet metal shapes

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1012401A (en) * 1907-09-03 1911-12-19 Piercy B Mccullough Dental swaging apparatus.
US1613595A (en) * 1925-01-21 1927-01-11 Patent Button Co Method of making metal articles
US2168641A (en) * 1938-03-07 1939-08-08 Northern Indiana Brass Co Die mechanism
US2783727A (en) * 1951-09-12 1957-03-05 Lake Erie Engineering Corp Cushion die structure for apparatus for pressing sheet metal shapes

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4356612A (en) * 1980-03-31 1982-11-02 Cameron Iron Works, Inc. Method of producing a forged product
US4422236A (en) * 1981-10-01 1983-12-27 General Electric Company Method of extruding parts with captured fixture
US5934876A (en) * 1997-10-21 1999-08-10 Beckett Air Incorporated Blower wheel assembly with steel hub having cold-headed lugs, and method of making same
US6179566B1 (en) 1997-10-21 2001-01-30 Beckett Air Incorporated Blower Wheel assembly with steel hub, and method of making same
US6206640B1 (en) 1997-10-21 2001-03-27 Beckett Air Incorporated Blower wheel assembly with steel hub, and method of making same
US6220818B1 (en) 1997-10-21 2001-04-24 Beckett Air Incorporated Blower wheel assembly with steel hub, and method of making same
US20110113850A1 (en) * 2008-01-03 2011-05-19 General Electric Company Near net shape forging process for compressor and turbine wheels and turbine spacer wheels
US8256260B2 (en) * 2008-01-03 2012-09-04 General Electric Company Near net shape forging process for compressor and turbine wheels and turbine spacer wheels
US7895873B1 (en) * 2008-04-23 2011-03-01 Meadville Forging Co LP Method and system for simultaneously forging two parts

Also Published As

Publication number Publication date
GB999228A (en) 1965-07-21
CH414321A (de) 1966-05-31
DE1527462A1 (de) 1970-01-22

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