US20100290942A1

US20100290942A1 - Systems and methods to produce forged powder metal parts with transverse features

Info

Publication number: US20100290942A1
Application number: US12/466,456
Authority: US
Inventors: Edward P. Becker; Anil K. Sachdev
Original assignee: GM Global Technology Operations LLC
Current assignee: GM Global Technology Operations LLC
Priority date: 2009-05-15
Filing date: 2009-05-15
Publication date: 2010-11-18
Also published as: CN101885068B; DE102010020167A1; CN101885068A

Abstract

Systems and methods produce forged powder metal parts respectively comprising a transverse feature. A system may comprise a powder metal die, a sintering oven, a forging apparatus, a core material, and a powder metal. The powder metal die may receive and compact the core material and the powder metal to form a compacted powder metal part with at least a portion of the core material embedded therein to define a transverse feature in the compacted powder metal part. The sintering oven may receive and sinter the compacted powder metal part with the core material remaining embedded therein to maintain the definition of the transverse feature during sintering. The forging apparatus may receive and forge the sintered powder metal part with the core material remaining embedded therein to maintain the definition of the transverse feature during forging with the embedded core material being removable from the forged powder metal thereafter.

Description

BACKGROUND

The present invention relates generally to powder metal parts with transverse features. More particularly, the invention relates to systems and methods to produce forged powder metal parts with transverse features.
Conventional systems and methods of the prior art to produce powder metal parts having transverse features utilize core materials to define the transverse features during compacting and sintering phases of powder metal part manufacturing processes. The utilized core materials, however, are formed substantially of matter(s) that has a melting point lower than fusion temperatures of the powder metal achieved during sintering phases. As such, the core material melts, vaporizes, and/or infiltrates the powder metal part during sintering phases. Such matter(s) forming the core materials typically include copper and/or zinc. With the melting, vaporization, and/or infiltration of the core material into the powder metal part, the transverse feature is provided therein as a void region.
Such conventional systems and methods, however, are not suitable for powder metal parts to be forged. Forging strengthens powder metal parts such that forged powder metal parts typically are stronger than cast or machined metal parts. Powder metal parts produced according to conventional systems and methods where the core material is melted, vaporized, and/or infiltrated into the part are subject to deformation. More particularly, the void region defining the transverse feature formerly defined and occupied by the core material prior to sintering, generally at least partially collapses during forging since the core material is absent from the void region, leaving nothing to prevent the metal from filling the void region when subjected to the compressive forces commonly associated with forging processes. Other conventional approaches that do not utilize core materials to define transverse features in powder metal parts typically require completion of machining operations of the parts, which often is difficult, time-consuming, and costly. As such, based on the foregoing, there exists a need for systems and methods that utilize core materials to produce forged powder metal parts with transverse features and that do not require completion of subsequent machining.

SUMMARY

It is against the above background that embodiments of the present invention generally relate to systems and methods that utilize core materials to produce forged powder metal parts with transverse features.
In accordance with one embodiment, a method of producing a forged powder metal part comprising a transverse feature comprises providing a powder metal die and positioning a core material in the die. The method also comprises filling the die at least partially with a powder metal to at least partially cover the core material with the powder metal and compacting with the die the powder metal to form a compacted powder metal part with at least a portion of the core material embedded therein, wherein the embedded core material defines a transverse feature formed in the compacted powder metal part. Thereafter, the method comprises sintering the compacted powder metal part to form a sintered powder metal part with the core material remaining embedded therein to maintain the definition of the transverse feature during the sintering of the compacted powder metal part and forging the sintered powder metal part to form a forged powder metal part with the core material remaining embedded therein to maintain the definition of the transverse feature during the forging of the sintered powder metal part. Following the forging of the powder metal part, the method comprises removing the embedded core material from the forged powder metal part.
Optionally, the core material may be frangible. The frangible core material may be sufficiently brittle so as to be at least partially pulverized during the forging of the sintered powder metal part. The frangible core material may be at least partially broken during the forging of the sintered powder metal part. The frangible core material may comprise a degree of resiliency sufficient such that the at least partially broken frangible core material maintains the definition of the transverse feature during the forging of the sintered powder metal part. Further, the core material may comprise at least one of graphite and ceramic. The core material may not melt, vaporize, infiltrate, or otherwise dissipate during the compacting of the powder metal, the sintering of the compacted powder metal part, and the forging of the sintered powder metal part, and any combination thereof. The core material may be positioned in the die prior to the filling of the die with the powder metal or may be positioned in the die during the filling of the die with the powder metal. The embedded core material may be removed from the forged powder metal part via at least one of a shaking, a reaming, a brushing, and an air blowing of the forged powder metal part.
Further, optionally, the transverse feature may comprises a depression of any one or more shapes, sizes, and dimensions in the forged powder metal part. The transverse feature may comprise at least one of a hole, a groove, a passage, a recess, an indentation, a thread, a cavity, an undercut, a crosscut, and an impression. The forged powder metal part may comprise a connecting rod of a reciprocating piston engine and the transverse feature comprises a lubricant passage between a crank end and a piston end of the connecting rod. The lubricant passage may connect the crank end and the piston end of the connecting rod so as to permit passage of a lubricant there-between.
In accordance with another embodiment, a method of producing a forged powder metal part comprising a transverse feature comprises providing a powder metal die and positioning a frangible core material in the die. The method also comprises filling the die at least partially with a powder metal to at least partially cover the frangible core material with the powder metal. Thereafter, the method comprises compacting with the die the powder metal to form a compacted powder metal part with at least a portion of the frangible core material embedded therein, wherein the embedded frangible core material defines a transverse feature formed in the compacted powder metal part, sintering the compacted powder metal part to form a sintered powder metal part, wherein the frangible core material remains embedded therein and does not melt, vaporize, infiltrate, or otherwise dissipate during the sintering so as to maintain the definition of the transverse feature during the sintering of the compacted powder metal part, and forging the sintered powder metal part to form a forged powder metal part with the frangible core material remaining embedded therein to maintain the definition of the transverse feature during the forging of the sintered powder metal part. The method further comprises removing the embedded frangible core material from the forged powder metal part.
In accordance with yet another embodiment, a system to produce a forged power metal part comprising a transverse feature comprises a powder metal die, a sintering oven, a forging apparatus, a core material, and a powder metal. The powder metal die is operable to receive and compact the core material and the powder metal to form a compacted powder metal part with at least a portion of the core material embedded therein, wherein the embedded core material defines a transverse feature formed in the compacted powder metal part. The sintering oven is operable to receive and sinter the compacted powder metal part to form a sintered powder metal part with the core material remaining embedded therein to maintain the definition of the transverse feature during a sintering of the compacted powder metal part by the sintering oven. The forging apparatus is operable to receive and forge the sintered powder metal part to form a forged powder metal part with the core material remaining embedded therein to maintain the definition of the transverse feature during a forging of the sintered powder metal part by the forging apparatus. The embedded core material is removable from the forged powder metal.
Optionally, the core material may be frangible and may be at least partially broken during the forging of the sintered powder metal part. The frangible core material may comprise a degree of resiliency sufficient such that the at least partially broken frangible core material maintains the definition of the transverse feature during the forging of the sintered powder metal part by the forging apparatus. The core material may not melt, vaporize, infiltrate, or otherwise dissipate during the compacting of the powder metal, the sintering of the compacted powder metal part, and the forging of the sintered powder metal part, and any combination thereof. The core material may comprise at least one of graphite and ceramic.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description of specific embodiments can be best understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:

FIG. 1 illustrates a system to produce a forged powder metal part with a transverse feature according to one embodiment of the present invention; and

FIG. 2 illustrates a cross-sectional view of a connecting rod forged powder metal part produced according to an embodiment of the present invention.

The embodiments set forth in the drawings are illustrative in nature and are not intended to be limiting of the embodiments defined by the claims. Moreover, individual aspects of the drawings and the embodiments will be more fully apparent and understood in view of the detailed description that follows.

DETAILED DESCRIPTION

As mentioned above, embodiments of the present invention relate generally to systems and methods that utilize core materials to produce forged powder metal parts with transverse features. As used herein, “transverse features” include, but are not limited to, depressions of any one or more shapes, sizes, and dimensions in forged powder metal parts. Such depressions, and, thus, transverse features, may include, but are not limited to, holes, grooves, passages, recesses, indentations, threads, cavities, undercuts, crosscuts, and impressions. Further, as used herein, “powder metal” may include, but is not limited to, an aluminum, a titanium, an iron, a steel, a brass, a stainless steel, a bronze, any alloys thereof, and any combination thereof.
Referring initially to FIG. 1, one embodiment of the present invention relates to a system 10 to produce a forged powder metal part 28 comprising a transverse feature. The system 10 comprises a powder metal 12, a core material 14, a powder metal die 16, a sintering oven 20, and a forging apparatus 24. As mentioned above, the powder metal 12 may comprise at least one of a variety of metals and alloys thereof. The core material 14 is at least partially embedded into the powder metal during compacting, sintering, and forging thereof. The embedded core material shapes the powder metal accordingly. More particularly, the core material 14 defines the shapes, sizes, and dimensions of a transverse feature formed in the powder metal 12 through the compacting, sintering, and forging thereof by the system 10.
The core material 14 is configured at least substantially of a material that does not melt, vaporize, infiltrate, or otherwise dissipate during the compacting, sintering, and forging, and any combination thereof, of the powder metal 12. Thus, the core material 14 comprises a melting temperature higher than the fusion temperature of the powder metal during sintering thereof. Such materials include, but are not limited to, graphite and ceramic. Thus, in one embodiment, the core material 14 comprises at least one of graphite and ceramic. As used herein, “dissipate” refers generally to a withdrawal of the core material 14 from the formed transverse feature. For example, a core material that melts or vaporizes may infiltrate the powder metal and, thereby, no longer be confined to the transverse feature formed by the core material.
The powder metal die 16 may be any conventional die known or later developed in the art that is operable to compact the powder metal as described herein. The powder metal die 16 is operable to receive the powder metal 12 and the core material 14. The core material 14 is positioned in the die 16 according to a desired position for the transverse feature to be formed in the powder metal 12. The core material 14 may be positioned in the die 16 either prior to or during the filling of the die 16 with the powder metal 12. The die 16 is filled at least partially with the powder metal 12 so that the core material 14 is at least partially covered with the powder metal 12. The die 16 also is operable to compact the core material 14 and the powder metal 12 positioned therein. The die 16 compacts the core material 14 and the powder metal 12 to form a compacted metal part 18 with at least a portion of the core material embedded therein. The embedded core material defines the transverse feature formed in the compacted powder metal part 18.
The sintering oven 20 is operable to receive and sinter the compacted powder metal part 18 with the embedded core material. Thereby, the sintering oven 20 forms a sintered powder metal part 22 with the embedded core material remaining embedded therein. As such, the embedded core material maintains the definition of the transverse feature during the sintering of the compacted powder metal part 18 by the sintering oven 20.
The forging apparatus 24 is operable to receive and forge the sintered powder metal part 22 with the embedded core material. Thereby, the forging apparatus 24 forms a forged powder metal part 26 with the embedded core material remaining embedded therein. As such, the embedded core material maintains the definition of the transverse feature during the forging of the sintered powder metal part 22 by the forging apparatus 24. The embedded core material is removable from the forged powder metal part 26 to produce a forged powder metal part 28 with an exposed transverse feature. The embedded core material may be removed, generally after sufficiently cooling, from the forged powder metal part 26 via at least one of a shaking, a brushing, and an air blowing of the forged powder metal part 26 to result in the forged powder metal part 28 with the exposed transverse feature.
The core material 14 may be frangible such that it is sufficiently brittle so as to be at least partially pulverized during the forging of the sintered powder metal part 22 by the forging apparatus 24. For example, the frangible core material may be at least partially broken during the forging of the sintered powder metal part 22. The frangible core material may comprise a degree of resiliency sufficient such that the at least partially broken core material maintains the definition of the transverse feature during the forging of the sintered powder metal part. A breaking of the core material into smaller parts may facilitate the removal of the embedded core material from the powder metal part following completion of forging processes.
The presence of the embedded core material in the sintered powder metal part substantially prevents closure of the transverse feature during forging processes. Otherwise, should the embedded core material melt, vaporize, dissipate, or otherwise be removed from the transverse feature, the compressive forces applied to powder metal parts by forging apparatuses during forging processes generally is sufficient to cause the powder metal to collapse and at least partially fill in the transverse feature abandoned by the core material.
It is contemplated by the present inventors that the forged powder metal part 28 with the transverse feature may any part attainable with an embodiment of the present invention. In one embodiment, for example, as shown in FIG. 2, the forged powder metal part 28 comprises a connecting rod 30 of a reciprocating piston engine and the transverse feature 32 comprises a lubricant passage 34 between a crank end 36 and a piston end 38 of the connecting rod 30. The lubricant passage 34 may connect the crank end 36 and the piston end 38 of the connecting rod 30 so as to permit passage of a lubricant there-between.
Additional embodiments of the present invention relate generally to methods of producing forged powder metal parts with transverse features. In accordance with one such embodiment, a method produces a forged powder metal part comprising a transverse feature, as follows: position a core material in a powder metal die; fill the die at least partially with a powder metal such that the core material is at least partially covered thereby; operate the die to compact the powder metal and the core material to form a compacted powder metal part with at least a portion of the core material embedded therein so that the embedded core material defines a transverse feature in the compacted powder metal part; position the compacted powder metal part with the embedded core material in a sintering oven; operate the sintering oven to sinter the compacted powder metal and the embedded core material to form a sintered powder metal part with the embedded core material remaining embedded therein throughout the sintering process to maintain the definition of the transverse feature; position the sintered powder metal part with the embedded core material in a forging apparatus; operate the forging apparatus to forge the sintered powder metal part and the embedded core material to form a forged powder metal part with the embedded core material remaining embedded therein throughout the forging process to maintain the definition of the transverse feature; remove the embedded core material from the forged powder metal part to expose the transverse feature therein.
It is noted that recitations herein of a component of an embodiment being “configured” in a particular way or to embody a particular property, or function in a particular manner, are structural recitations as opposed to recitations of intended use. More specifically, the references herein to the manner in which a component is “configured” denotes an existing physical condition of the component and, as such, is to be taken as a definite recitation of the structural factors of the component.
It is noted that terms like “generally,” “commonly,” and “typically,” when utilized herein, are not utilized to limit the scope of the claimed embodiments or to imply that certain features are critical, essential, or even important to the structure or function of the claimed embodiments. Rather, these terms are merely intended to identify particular aspects of an embodiment or to emphasize alternative or additional features that may or may not be utilized in a particular embodiment.
For the purposes of describing and defining embodiments herein it is noted that the terms “substantially,” “significantly,” and “approximately” are utilized herein to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation. The terms “substantially,” “significantly,” and “approximately” are also utilized herein to represent the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue.
Having described embodiments of the present invention in detail, and by reference to specific embodiments thereof, it will be apparent that modifications and variations are possible without departing from the scope of the embodiments defined in the appended claims. More specifically, although some aspects of embodiments of the present invention are identified herein as preferred or particularly advantageous, it is contemplated that the embodiments of the present invention are not necessarily limited to these preferred aspects.

Claims

1. A method of producing a forged powder metal part comprising a transverse feature, the method comprising:

providing a powder metal die;

positioning a core material in the die;

filling the die at least partially with a powder metal to at least partially cover the core material with the powder metal;

compacting with the die the powder metal to form a compacted powder metal part with at least a portion of the core material embedded therein, wherein the embedded core material defines a transverse feature formed in the compacted powder metal part;

sintering the compacted powder metal part to form a sintered powder metal part with the core material remaining embedded therein to maintain the definition of the transverse feature during the sintering of the compacted powder metal part;

forging the sintered powder metal part to form a forged powder metal part with the core material remaining embedded therein to maintain the definition of the transverse feature during the forging of the sintered powder metal part; and

removing the embedded core material from the forged powder metal part.

2. The method of claim 1, wherein the core material is frangible.

3. The method of claim 2, wherein the frangible core material is sufficiently brittle so as to be at least partially pulverized during the forging of the sintered powder metal part.

4. The method of claim 2, wherein the frangible core material is at least partially broken during the forging of the sintered powder metal part.

5. The method of claim 4, wherein the frangible core material comprises a degree of resiliency sufficient such that the at least partially broken frangible core material maintains the definition of the transverse feature during the forging of the sintered powder metal part.

6. The method of claim 1, wherein the core material comprises at least one of graphite and ceramic.

7. The method of claim 1, wherein the core material does not melt, vaporize, infiltrate, or otherwise dissipate during the compacting of the powder metal, the sintering of the compacted powder metal part, and the forging of the sintered powder metal part, and any combination thereof.

8. The method of claim 1, wherein the core material is positioned in the die prior to the filling of the die with the powder metal.

9. The method of claim 1, wherein the core material is positioned in the die during the filling of the die with the powder metal.

10. The method of claim 1, wherein the embedded core material is removed from the forged powder metal part via at least one of a shaking, a reaming, a brushing, and an air blowing of the forged powder metal part.

11. The method of claim 1, wherein the transverse feature comprises a depression of any one or more shapes, sizes, and dimensions in the forged powder metal part.

12. The method of claim 11, wherein the transverse feature comprises at least one of a hole, a groove, a passage, a recess, an indentation, a thread, a cavity, an undercut, a crosscut, and an impression.

13. The method of claim 1, wherein the forged powder metal part comprises a connecting rod of a reciprocating piston engine and the transverse feature comprises a lubricant passage between a crank end and a piston end of the connecting rod.

14. The method of claim 13, wherein the lubricant passage connects the crank end and the piston end of the connecting rod so as to permit passage of a lubricant there-between.

15. A method of producing a forged powder metal part comprising a transverse feature, the method comprising:

providing a powder metal die;

positioning a frangible core material in the die;

filling the die at least partially with a powder metal to at least partially cover the frangible core material with the powder metal;

compacting with the die the powder metal to form a compacted powder metal part with at least a portion of the frangible core material embedded therein, wherein the embedded frangible core material defines a transverse feature formed in the compacted powder metal part;

sintering the compacted powder metal part to form a sintered powder metal part, wherein the frangible core material remains embedded therein and does not melt, vaporize, infiltrate, or otherwise dissipate during the sintering so as to maintain the definition of the transverse feature during the sintering of the compacted powder metal part;

forging the sintered powder metal part to form a forged powder metal part with the frangible core material remaining embedded therein to maintain the definition of the transverse feature during the forging of the sintered powder metal part; and

removing the embedded frangible core material from the forged powder metal part.

16. A system to produce a forged power metal part comprising a transverse feature, the system comprising a powder metal die, a sintering oven, a forging apparatus, a core material, and a powder metal, wherein:

the powder metal die is operable to receive and compact the core material and the powder metal to form a compacted powder metal part with at least a portion of the core material embedded therein, wherein the embedded core material defines a transverse feature formed in the compacted powder metal part;

the sintering oven is operable to receive and sinter the compacted powder metal part to form a sintered powder metal part with the core material remaining embedded therein to maintain the definition of the transverse feature during a sintering of the compacted powder metal part by the sintering oven; and

the forging apparatus is operable to receive and forge the sintered powder metal part to form a forged powder metal part with the core material remaining embedded therein to maintain the definition of the transverse feature during a forging of the sintered powder metal part by the forging apparatus,

wherein the embedded core material is removable from the forged powder metal.

17. The system of claim 16, wherein the core material is frangible and is at least partially broken during the forging of the sintered powder metal part.

18. The system of claim 17, wherein the frangible core material comprises a degree of resiliency sufficient such that the at least partially broken frangible core material maintains the definition of the transverse feature during the forging of the sintered powder metal part by the forging apparatus.

19. The system of claim 16, wherein the core material does not melt, vaporize, infiltrate, or otherwise dissipate during the compacting of the powder metal, the sintering of the compacted powder metal part, and the forging of the sintered powder metal part, and any combination thereof.

20. The system of claim 16, wherein the core material comprises at least one of graphite and ceramic.