US3871200A - Method and apparatus for producing sintered metal product - Google Patents

Method and apparatus for producing sintered metal product Download PDF

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Publication number
US3871200A
US3871200A US376061A US37606173A US3871200A US 3871200 A US3871200 A US 3871200A US 376061 A US376061 A US 376061A US 37606173 A US37606173 A US 37606173A US 3871200 A US3871200 A US 3871200A
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United States
Prior art keywords
billet
sintered metal
sintered
back pressure
extrusion
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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.)
Expired - Lifetime
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US376061A
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English (en)
Inventor
Mineo Onoda
Takahiko Kimura
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Sumitomo Electric Industries Ltd
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Sumitomo Electric Industries Ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/20—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces by extruding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/02—Compacting only
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/02—Compacting only
    • B22F2003/026—Mold wall lubrication or article surface lubrication
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/20—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces by extruding
    • B22F2003/202—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces by extruding with back pressure
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S29/00—Metal working
    • Y10S29/031—Pressing powder with other step
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S29/00—Metal working
    • Y10S29/047—Extruding with other step

Definitions

  • ABSTRACT A method for producing a sintered metal product
  • a lubricating coating such as zinc stearate on the surface of a billet composed of a sintered metal of low to medium density, maintaining it at a working temperature ranging from room temperature to 750C, applying a back pressure to the billet and extruding it.
  • a single action press can be used which is equipped with a punch for applying the back pressure.
  • the sintered metal product obtained has uniform high density and is free from surface and inner cracks with its inner pores not enlarged.
  • This invention relates to a method and an apparatus for producing a sintered metal product made of sintered iron, sintered steel or a sintered metal such as a sintered non-ferrous metal, especially a sintered metal product of high density for use as component parts of machines.
  • machine parts made of sintered metals have a complicated shape, they are in some cases required to be machined into final shapes. Furthermore,
  • oils are generally used as a pressure medium and lubricant.
  • the oils penetrate into an innumerable number of pores present in the sintered pre-form billet under high pressures, the extruded product tends to develop cracks easily both in its interior and on its surface. and does not get uniform high density.
  • a feature of this invention is to provide a method which comprises forming a lubricant coating on the surface of a sintered metal of low to medium density as an extruding material (to be referred to as billet), feeding the billet into a die hole called, a container exerting a back pressure thereon, and extruding it using a punch.
  • Another feature of this invention is to provide a very effective method for providing the lubricant coating.
  • Still another object of this invention is to provide an apparatus for exerting a back pressure on the billet and working it by extrusion using a punch.
  • an apparatus for producing a sintered metal product comprising a die hole for feeding thereinto a sintered metal billet of low to medium density with its surface coated with a lubricant coating, a first punch for applying an extruding pressure to the billet in the die hole, and a second punch for applying to the portion of the billet which has been deformed by the extruding pressure, a back pressure lower than the extruding pressure in a direction opposite to the direction of said deformation.
  • FIG. 1 is an explanatory view of a back pressureapplying device for use in the first example in accordance with the method of this invention
  • FIG. 2 is an explanatory view of a back pressureapplying device for use in the second example in accordance with the method of this invention
  • FIG. 3(a) shows the configuration of a billet in the first example of the invention
  • FIG. 3(b) is a vertical sectional view of a worked product made from the billet of FIG. 3(a);
  • FIG. 4(a) shows the configuration of a billet in the second example of the invention
  • FIG. 4(b) is a vertical sectional view of a worked product made from the billet of FIG. 4(a);
  • FIG. 4(c) is a side elevation of the product of FIG. b);
  • FIG. 4(d) is a top plan of the product of FIG. 4(b);
  • FIG. 5 is a graphic representation of the density distribution of a worked product obtained by the method of this invention using a sintered ferrous alloy
  • FIG. 6 is a graphic representation showing the state of detects of the sintered material by influences of the back pressure and the working temperature, (a) showing exterior defects and (b) showing interior defects;
  • FIG. 7(1), (2), (3) and (4) are microscope photographs of a worked product without back pressure (a) at positions 1, 2, 3, and 4, the product being formed into the configuration showing FIG. 3(b); and,
  • FIG. 8(1), (2) and (3) are microscopic photographs of a worked product (a) obtained in the first example by this invention at position 1, 2 and 3.
  • the critical feature of the present invention is that sintered pre-form is subjected to a back pressure which is minimum 20% of the extruding pressure, using a special back pressure applying device, and extruded at room temperature to 750C. to form parts or components of complicated configurations which cannot be easily obtained by ordinary sintered techniques.
  • the sintered pre-form Prior to extrusion, the sintered pre-form must be subjected to a lubricating treatment. If a liquid lubricant is directly coated on the pre-form, the liquid penetrates into the interior of the preform to prevent the collapsing of the pores, and it becomes difficult to increase the density of the resulting product. Moreover, if the lubricating liquid contaminates the walls of the pores, the strength of the product cannot be increased even if its density increases. These defects have been removed by the following lubricating treatment in accordance with the present invention.
  • porous sintered metal billet and a powdery solid lubricating material such as, a metallic soap (such as zinc stearate), M or graphite are placed in a rotary barrel together with elastic beads such as rubber or plastics that do not scar the sintered material, and tumbled together. This tumbling operation result in uniform and intimate adhesion of the solid lubricating material only on the surface of the sintered material without scarring.
  • the amount of the powdery solid lubricant is sufficiently such that it uniformly covers the surfaces of the sintered material and the elastomer beads. There is no significance in adding it in an amount of more than 40% by volume of the sintered material and the elasto mer beads, and moreover, the adhesion becomes nonuniform. On the other hand, amounts below 2'7: are in sufficient. It is recommended to heat the sintered preform to about 100C, because this not only results in improvement of the adhesion of the metallic soap, but also makes it possible to adhere an inorganic lubricant such as graphite conjointly.
  • the amount of the elastic beads is at least equal in volume to the sintered material. Within this range of the amount, there is hardly any scar, and a uniform adhesion can be obtained. If the amount of the elastomer beads is smaller, the material undergoes scars as a result of hitting, and these scars do not disappear even after coining.
  • the tumbling is performed using an ordinary rotary barrel for use in deburring.
  • a period of 3 minutes is sufficient for the tumbling, and there is no significance in continuing the tumbling for too long periods of time.
  • Another effective procedure for providing the lubricous coating on the surface of the sintered metal comprises spraying a solution in an organic solvent, or a suspension in water, of a solid lubricant such as a metallic soap such as zinc stearate, M05 graphite or glass onto the sintered material heated to a temperature above the boiling point of the organic solvent or water, and instantaneously evaporating off only the solvent or water on the surface of the sintered material, thereby to adhere the solid lubricant only to the surface of the sintered material without penetration of the liquid into the interior of the pores.
  • a solid lubricant such as a metallic soap such as zinc stearate, M05 graphite or glass
  • the temperature at which the material is heated may be above the evaporating point of the solvent. However, too high temperatures are undesirable since the solvent is volatilized before the solution spray reaches the sintered material. If the solvent is water, the suitable heating temperature is 150 to 250C., and if the solvent is methylene chloride, it is 40 to 60C.
  • a back pressure is required to be applied to the billet through its extrusion free surface in a direction opposite to the extrusion direction at the same time as the initiation of extrusion.
  • This application of back pressure makes it possible to prevent the enlargement of the pores, and the formation of cracks both on the surface and in the interior of the sintered billet.
  • the back pressure-applying device for use in the present invention is designed to remove these defects, and a solid pressure medium is used for applying back pressure to the sintered preform billet.
  • This device can easily be mounted on a single-action mechanical press. Examples of this device are illustrated in FIGS. 1 and 2.
  • FIG. 1 shows an assembly of an apparatus for working the material by forward extrusion.
  • the left half of the figure shows the state of the apparatus before working, and the right half, the state of the apparatus after working.
  • the apparatus includes a punch l, a die 2, an ejector (lower punch) 3, a knockout pin 4, a fitting plate 5, a knockout pin guide plate 6, an oil hole 9, a relief valve 10, an upper ram 11 of a press, and a table 12 of the press.
  • the reference numeral 8 designates the workpiece.
  • a space 7 surrounded by the fitting plate 5, knockout pin guide plate 6, ejector 3 and knockout pin 4 is maintained air-tight by O-rings.
  • the pressed (25 kg/mm oil fed from the oil hole 9 provided in the fitting plate 5 causes the ejec tor to move upwards and the knockout pin to move downwards.
  • the workpiece is rapidly extruded to push down the ejector, and an oil pressure is generated in the space 7.
  • the pressure can be controlled by the relief valve 10.
  • the total working pressure at this time is [30 kg/mm*.
  • FIG. 2 shows an assembly of an apparatus for working the material by backward extrusion.
  • a punch for applying a back pressure is shown at 13, a punch holder at 14, a fitting plate for applying a back pressure at 15, and an upper punch fitting plate at 16.
  • the punch 13 is adapted to slide vertically along an upper punch 1.
  • a space 7 surrounded by the punch holder 14, the fitting plate 15, fitting plate 16 and upper punch l is maintained air-tight by O-rings.
  • the pressure of air or oil (5 kg/cm fed from an oil or air hole 9 provided in the upper punch fitting plate 16 causes the punch 13 to move downwards.
  • the outside diameter of the fitting plate 15 is so determined as to generate a pressure of 20 kg/mm at the end surface of the punch.
  • Machine parts or components of uniformly high density can be obtained
  • the method is economical since there is no need for using expensive double action presses
  • EXAMPLE 1 Each of four starting powders of Fe, Fe-0.2C, Fe- 0.4C and Fe-3Ni-O.3Mo-0.5C was mixed with 0.8% of zinc stearate in a mixer. The mixture was molded into a billet with a size of25 X 17.5 mm and a density of 6.8 g/cm dewaxed for 1 hour at 550C., and then sintered for 30 minutes in an atmosphere of H in a continuous sintering furnace at l250C.
  • a lubricant coating was formed on the resulting billet by tumbling with zinc stearate (when the billet was to be worked at room temperature), or by spraying a suspension of graphite on the heated billet (when the billet was to be worked at elevated temperatures).
  • the billet was then heated for about 20 minutes in a furnace containing 21 hydrogen gas atmosphere and held at room temperature to 750C, and transported therefrom to a die hole called a container. It was fabricated into a forged product of the desired shape by a forging press equipped with a back pressure applying device.
  • FIG. 6 shows that the properties of the sintered material in its interior and on its surface were very good as a result of applying back pressure at a heating temperature of 450C. and this substantiates the superiority of the method of this invention.
  • EXAMPLE 2 Copper powders obtained by electrolysis were compacted to a density of 7.9 g/cm, and sintered in an atmosphere of H at 790C. for 1 hour to form billet (20 (b X A coating of zinc stcarate was formed on the surface of the billet by the tumbling method described above, and the billet was subjected to extrusion working at room temperature using an apparatus of the type shown in FIG. 2.
  • the sintered metal product thus obtained has a higher, more uniform density and is free from surface and inner crack with its inner pores not enlarged.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Forging (AREA)
  • Powder Metallurgy (AREA)
  • Lubricants (AREA)
  • Extrusion Of Metal (AREA)
US376061A 1973-02-06 1973-07-02 Method and apparatus for producing sintered metal product Expired - Lifetime US3871200A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP48014964A JPS5146500B2 (de) 1973-02-06 1973-02-06

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US3871200A true US3871200A (en) 1975-03-18

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US (1) US3871200A (de)
JP (1) JPS5146500B2 (de)
DE (1) DE2333136A1 (de)
FR (1) FR2221210A1 (de)
GB (1) GB1416103A (de)
IT (1) IT985820B (de)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4197757A (en) * 1977-04-13 1980-04-15 Hackett Kenneth P Method and apparatus for the cold forming of metal
FR2469222A1 (fr) * 1979-11-14 1981-05-22 Hackett Kenneth Procede et appareil pour le faconnage de metal par extrusion a froid
US4341106A (en) * 1977-04-13 1982-07-27 Gleason Works Apparatus for controlling the movement of a reciprocatory hydraulically driven element of a metal forming machine
US4388054A (en) * 1980-04-25 1983-06-14 Asea Aktiebolag Method for manufacturing elongated bodies by extrusion of powder in a capsule
US4632702A (en) * 1985-10-15 1986-12-30 Worl-Tech Limited Manufacture and consolidation of alloy metal powder billets
US4699657A (en) * 1986-11-03 1987-10-13 Worl-Tech Limited Manufacture of fine grain metal powder billets and composites
US4882924A (en) * 1987-09-15 1989-11-28 Sanshin Industry Co., Ltd. Method and apparatus for manufacturing hollow cylindrical guide roller for magnetic recording tape
GB2235700A (en) * 1989-08-18 1991-03-13 Alsthom Gec Methods of manufacture of neodymium-iron-boron alloy pressings
US5400633A (en) * 1993-09-03 1995-03-28 The Texas A&M University System Apparatus and method for deformation processing of metals, ceramics, plastics and other materials
US6086970A (en) * 1998-04-28 2000-07-11 Scimed Life Systems, Inc. Lubricious surface extruded tubular members for medical devices
WO2003055619A1 (fr) * 2001-12-26 2003-07-10 Nihon Parkerizing Co., Ltd. Procede et appareil de formation d'un film lubrifiant
US20070243312A1 (en) * 2006-04-06 2007-10-18 C3 Materials Corp. Microstructure applique and method for making same

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5680314A (en) * 1979-12-03 1981-07-01 Pooru Haketsuto Kenesu Cold extruding molding method and its device
JP2612072B2 (ja) * 1989-08-31 1997-05-21 日立粉末冶金株式会社 塑性加工用の筒状鉄系焼結スラグ、およびその製造方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3645728A (en) * 1970-06-03 1972-02-29 Gen Motors Corp Method for making spark plug shells
US3686910A (en) * 1968-03-20 1972-08-29 Western Electric Co Methods of and apparatus for hydrostatic forming
US3785038A (en) * 1968-08-20 1974-01-15 Krebsoege Gmbh Sintermetall Process of working a sintered powder metal compact

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3686910A (en) * 1968-03-20 1972-08-29 Western Electric Co Methods of and apparatus for hydrostatic forming
US3785038A (en) * 1968-08-20 1974-01-15 Krebsoege Gmbh Sintermetall Process of working a sintered powder metal compact
US3645728A (en) * 1970-06-03 1972-02-29 Gen Motors Corp Method for making spark plug shells

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4197757A (en) * 1977-04-13 1980-04-15 Hackett Kenneth P Method and apparatus for the cold forming of metal
US4341106A (en) * 1977-04-13 1982-07-27 Gleason Works Apparatus for controlling the movement of a reciprocatory hydraulically driven element of a metal forming machine
FR2469222A1 (fr) * 1979-11-14 1981-05-22 Hackett Kenneth Procede et appareil pour le faconnage de metal par extrusion a froid
US4388054A (en) * 1980-04-25 1983-06-14 Asea Aktiebolag Method for manufacturing elongated bodies by extrusion of powder in a capsule
US4632702A (en) * 1985-10-15 1986-12-30 Worl-Tech Limited Manufacture and consolidation of alloy metal powder billets
US4699657A (en) * 1986-11-03 1987-10-13 Worl-Tech Limited Manufacture of fine grain metal powder billets and composites
US4882924A (en) * 1987-09-15 1989-11-28 Sanshin Industry Co., Ltd. Method and apparatus for manufacturing hollow cylindrical guide roller for magnetic recording tape
GB2235700A (en) * 1989-08-18 1991-03-13 Alsthom Gec Methods of manufacture of neodymium-iron-boron alloy pressings
GB2235700B (en) * 1989-08-18 1993-06-09 Alsthom Gec Methods of manufacture of neodymium-iron-boron alloy pressings
US5400633A (en) * 1993-09-03 1995-03-28 The Texas A&M University System Apparatus and method for deformation processing of metals, ceramics, plastics and other materials
US6086970A (en) * 1998-04-28 2000-07-11 Scimed Life Systems, Inc. Lubricious surface extruded tubular members for medical devices
WO2003055619A1 (fr) * 2001-12-26 2003-07-10 Nihon Parkerizing Co., Ltd. Procede et appareil de formation d'un film lubrifiant
US20070243312A1 (en) * 2006-04-06 2007-10-18 C3 Materials Corp. Microstructure applique and method for making same
US7722735B2 (en) * 2006-04-06 2010-05-25 C3 Materials Corp. Microstructure applique and method for making same

Also Published As

Publication number Publication date
JPS49102563A (de) 1974-09-27
IT985820B (it) 1974-12-20
GB1416103A (en) 1975-12-03
DE2333136A1 (de) 1974-08-22
JPS5146500B2 (de) 1976-12-09
FR2221210A1 (de) 1974-10-11

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