HYDROSTATIC CYCLIC EXPANSION EXTRUSION PROCESS FOR PRODUCING ULTRAFINE-GRAINED RODS
A method of producing ultrafine-grained materials and a system for mass production of ultrafine-grained materials is disclosed. The system includes a die assembly with a die channel that extends from a first end to a second end. The system also includes first punch and a second punch. A lubricant is poured into a portion of the die channel to surround a workpiece that is positioned within the die channel in order to minimize the effects of friction during processing.
This application claims the benefit of priority from Iran Patent Application Serial Number 139550140003008482, filed on Oct. 5, 2016, and entitled “HYDROSTATIC CYCLIC EXPANSION EXTRUSION (HCEE) PROCESS FOR PRODUCING UFG HIGH STRENGTH LONG RODS,” which is incorporated herein by reference in its entirety.BACKGROUND
Ultrafine-grained and nanostructured materials are materials that possess particularly high strength. Structures made of ultrafine-grained and nanostructured materials are often suitable for making lighter and at the same time energy efficient vehicles, airplanes, and other machinery. A variety of methods have been developed to produce ultrafine-grained (UFG) materials. For example, processing through the use of various metalworking techniques such as severe plastic deformation (SPD) can apply strain to produce ultrafine grained and nanostructured materials. In some cases, SPD may be understood as a process in which high strain is applied without any significant change in the dimensions of a workpiece.SUMMARY
This summary is intended to provide an overview of the subject matter of this patent, and is not intended to identify essential elements or key elements of the subject matter, nor is it intended to be used to determine the scope of the claimed implementations. The proper scope of this patent may be ascertained from the claims set forth below in view of the detailed description below and the drawings.
In one aspect, the present disclosure is directed to a method of producing ultrafine grain materials that includes positioning a workpiece in a die channel, the die channel being formed in a die assembly, pouring lubricant into a first end of the die channel, thereby substantially surrounding the workpiece with the lubricant, and moving a first punch toward the workpiece and thereby pushing the workpiece toward a second end of the die channel.
The above general aspect may include one or more of the following features. For example, the method can further include inserting a first seal into the first end of the die channel, thereby sealing the lubricant in the die channel. The method can also include a step of inserting the first punch into the first end of the die channel, as well as inserting a second punch into the second end of the die channel. In some cases, the method can include rotating the die assembly approximately 180 degrees to complete a first pass, and/or pouring additional lubricant into the second end of the die channel during a second pass. In addition, in some implementations, the method includes inserting a second seal into the second end of the die channel during the second pass, and/or inserting the first punch into the second end of the die channel. In another example, the method can include removing the second punch from the die assembly, and/or removing the first seal from the die assembly.
In another aspect, the present disclosure is directed to a die assembly for production of ultrafine-grain materials that includes a first die segment including a first die portion joined to a first panel portion and a second die segment including second die portion joined to a second panel portion. In addition, the first die segment is removably attached to the second die segment.
The above general aspect may include one or more of the following features. For example, the die assembly can further include a first plurality of fasteners configured to attach the first die portion to the first panel portion. In another example, the first panel portion may include a gasket. In some implementations, the first die portion has a substantially cylindrical shape, and/or the second die portion has a substantially cylindrical shape. In one implementation, the first die portion and the first panel portion include a plurality of apertures for receiving the first plurality of fasteners. In addition, in some cases, the die assembly includes a set of connectors configured to removably attach the first die segment to the second die segment. In one example, a die channel extends from the first die segment to the second die segment. In some implementations, the die channel includes an expansion section and an extrusion section, and a lubricant may fill or be disposed within the die channel, the lubricant being configured to substantially surround an entire exterior surface of a workpiece disposed in the die channel. Furthermore, the die assembly can be configured to apply hydrostatic pressure to a workpiece. In one implementation, a second plurality of fasteners may be configured to attach the second die portion to the second panel portion.
Other systems, methods, features and advantages of the implementations will be, or will become, apparent to one of ordinary skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description and this summary, be within the scope of the implementations, and be protected by the following claims.
The implementations can be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the implementations. Moreover, in the figures, like reference numerals designate corresponding parts throughout the different views.
In the following detailed description, various examples are presented to provide a thorough understanding of inventive concepts, and various aspects thereof that are set forth by this disclosure. However, upon reading the present disclosure, it may become apparent to persons of skill that various inventive concepts and aspects thereof may be practiced without one or more details shown in the examples. In other instances, well known procedures, operations and materials have been described at a relatively high-level, without detail, to avoid unnecessarily obscuring description of inventive concepts and aspects thereof.
As compared to more conventional coarse grained materials, UFG materials typically demonstrate highly improved mechanical, chemical and physical properties. In conventional Cyclic Expansion Extrusion (CEE) processes, long metal articles cannot be formed, because increased friction forces cause a fracture of the die and failure in the die. In the following disclosure, a Hydrostatic Cyclic Expansion Extrusion (HCEE) process is introduced, a process in which the limiting effects of friction is removed and workpieces of greater quality may be produced. In the HCEE process, the workpiece does not come into contact with the die and metal forming is achieved through pressurized lubricating fluid. In conventional methods, friction remains a limiting factor, making the production of long metal articles difficult or impossible.
Thus, an objective of the present disclosure is to present a novel process that allows for the production of workpieces without limitation on the length of the workpiece. For purposes of reference, this process will be referred to as Hydrostatic Cyclic Expansion Extrusion (HCEE). Generally, in HCEE, deformation is achieved through the application of compressed fluid, thereby reducing or eliminating friction. This reduction in friction can allow the HCEE process to be substantially independent of the length of the workpiece, making it possible to fabricate ultrafine grained materials of longer lengths. Thus the HCEE process makes the mass production of long metal UFG articles possible.
In different implementations, a cyclic extrusion expansion (CEE) system a die can comprise an axisymmetric barrel-like hollow, as well as one or more punches that can control or impose a flow of material. An extrusion section is placed after the part in which the sample experiences expansion. In one implementation, the force needed to extrude the material also provides the appropriate amount of back-pressure for expansion. Within the die cavity, the cylindrical material is initially expanded in diameter and then shrunk (usually returned to its original diameter) through an extrusion configuration. The material undertakes two portions of straining at expansion and extrusion. It can be understood that the HCEE process described herein can incorporate some or all features of the CEE system.
Referring now to
Referring now to both
In a third stage 230, lower punch 160 that had blocked the exit (associated with a second end 280 disposed toward the lower end of the die assembly) is removed, whereby the necessary back-pressure for expansion of the workpiece is provided by the subsequent extrusion that occurs after the expansion. Upper punch 160 moves further inward or downward through a first end 270, pushing the material such that it flows through the die cavity or die channel, and moving the workpiece material downward to its end point. At this point, the workpiece has gone through one pass of the HCEE process. If desired, additional passes can be performed, as represented by a fourth stage 240, where the apparatus (including workpiece 140) can be rotated approximately 180 degrees, such that first end 270 is now disposed toward the lower end of the die assembly and second end 280 is now disposed toward the upper end of the die assembly. After the assembly has been rotated, additional lubricant 230 is poured into the die, and another seal 220 can be added therein. The upper punch 160 can then be inserted or entered through the opposite opening (what had been the end associated with the exit), pressing the workpiece in a direction opposite to the previous direction. The additional lubricant ensures that friction continues to be minimized during the procedure. The apparatus can be rotated and the process can be performed any number of times until the workpiece is in the desired condition. In some cases it is necessary to remove the previous seal before refilling or pouring additional lubricant into the cavity.
In order to provide greater detail to the reader, an exploded view of an implementation of a die assembly for use in the HCEE system is presented next in
In different implementations, one or both set of components (i.e., first die portion 410 with first panel portion 420, and second die portion 430 with second panel portion 440) are securely fitted together as shown in
In addition, the four components are aligned and connected as shown in
For purposes of clarity, a cross-sectional view of die assembly 150 is also provided in
For purposes of illustration,
Thus, as presented herein, the HCEE process can provide for the fabrication of ultrafine-grained and/or nanostructured bulk articles in long lengths. Testing of the process has shown that articles comprising materials that have low formability in room temperature such as magnesium can be produced. Furthermore, it should be understood that in addition to the production of UFG long length rods at ambient temperature, the disclosed HCEE process and apparatus can be used at high temperature for materials that are not prone to deformation at room (or ambient) temperatures, such as magnesium and titanium, and other materials that deform only at relatively higher temperatures.
The inclusion of a layer of lubricating fluid provides the system with substantially reduced friction of the die as a result of the separation of the workpiece and the inner surface of the cavity. The production of long materials with a favorable strength-weight ratio offer many advantages to the automotive and aerospace industry. With the elimination of the effects of friction in the disclosed HCEE process, the mass production of long metal articles of ultrafine grained and nanostructured materials become possible.
While the foregoing has described what are considered to be the best mode and/or other examples, it is understood that various modifications may be made therein and that the subject matter disclosed herein may be implemented in various forms and examples, and that the teachings may be applied in numerous applications, only some of which have been described herein. It is intended by the following claims to claim any and all applications, modifications and variations that fall within the true scope of the present teachings.
Unless otherwise stated, all measurements, values, ratings, positions, magnitudes, sizes, and other specifications that are set forth in this specification, including in the claims that follow, are approximate, not exact. They are intended to have a reasonable range that is consistent with the functions to which they relate and with what is customary in the art to which they pertain.
The scope of protection is limited solely by the claims that now follow. That scope is intended and should be interpreted to be as broad as is consistent with the ordinary meaning of the language that is used in the claims when interpreted in light of this specification and the prosecution history that follows and to encompass all structural and functional equivalents. Notwithstanding, none of the claims are intended to embrace subject matter that fails to satisfy the requirement of Sections 101, 102, or 103 of the Patent Act, nor should they be interpreted in such a way. Any unintended embracement of such subject matter is hereby disclaimed.
Except as stated immediately above, nothing that has been stated or illustrated is intended or should be interpreted to cause a dedication of any component, step, feature, object, benefit, advantage, or equivalent to the public, regardless of whether it is or is not recited in the claims.
It will be understood that the terms and expressions used herein have the ordinary meaning as is accorded to such terms and expressions with respect to their corresponding respective areas of inquiry and study except where specific meanings have otherwise been set forth herein. Relational terms such as first and second and the like may be used solely to distinguish one entity or action from another without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by “a” or “an” does not, without further constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.
The Abstract of the Disclosure is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in various implementations. This is for purposes of streamlining the disclosure, and is not to be interpreted as reflecting an intention that the claimed implementations require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed implementation. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separately claimed subject matter.
While various implementations have been described, the description is intended to be exemplary, rather than limiting and it will be apparent to those of ordinary skill in the art that many more implementations and implementations are possible that are within the scope of the implementations. Although many possible combinations of features are shown in the accompanying figures and discussed in this detailed description, many other combinations of the disclosed features are possible. Any feature of any implementation may be used in combination with or substituted for any other feature or element in any other implementation unless specifically restricted. Therefore, it will be understood that any of the features shown and/or discussed in the present disclosure may be implemented together in any suitable combination. Accordingly, the implementations are not to be restricted except in light of the attached claims and their equivalents. Also, various modifications and changes may be made within the scope of the attached claims.
1. A method of producing ultrafine grain materials comprising:
- positioning a workpiece in a die channel, the die channel being formed in a die assembly;
- pouring lubricant into a first end of the die channel, thereby substantially surrounding the workpiece with the lubricant; and
- moving a first punch toward the workpiece and thereby pushing the workpiece toward a second end of the die channel.
2. The method according to claim 1, further comprising inserting a first seal into the first end of the die channel, thereby sealing the lubricant in the die channel.
3. The method according to claim 1, further comprising inserting the first punch into the first end of the die channel.
4. The method according to claim 3, further comprising inserting a second punch into the second end of the die channel.
5. The method according to claim 2, further comprising rotating the die assembly approximately 180 degrees to complete a first pass.
6. The method according to claim 5, further comprising pouring additional lubricant into the second end of the die channel during a second pass.
7. The method according to claim 6, further comprising inserting a second seal into the second end of the die channel during the second pass.
8. The method according to claim 7, further comprising inserting the first punch into the second end of the die channel.
9. The method according to claim 4, further comprising removing the second punch from the die assembly.
10. The method according to claim 7, further comprising removing the first seal from the die assembly.
11. A die assembly for production of ultrafine-grain materials comprising:
- a first die segment including a first die portion joined to a first panel portion;
- a second die segment including second die portion joined to a second panel portion; and
- the first die segment being removably attached to the second die segment.
12. The die assembly of claim 11, further comprising a first plurality of fasteners configured to attach the first die portion to the first panel portion.
13. The die assembly of claim 11, wherein the first panel portion comprises a gasket.
14. The die assembly of claim 11, wherein the first die portion has a substantially cylindrical shape.
15. The die assembly of claim 14, wherein the second die portion has a substantially cylindrical shape.
16. The die assembly of claim 11, wherein the first die portion and the first panel portion include a plurality of apertures for receiving the first plurality of fasteners.
17. The die assembly of claim 11, further comprising a set of connectors configured to removably attach the first die segment to the second die segment.
18. The die assembly of claim 11, further comprising a die channel extending from the first die segment to the second die segment.
19. The die assembly of claim 18, wherein the die channel includes an expansion section and an extrusion section.
20. The die assembly of claim 12, further comprising a second plurality of fasteners configured to attach the second die portion to the second panel portion.