CN113145675B - Bidirectional extrusion die for preparing ultra-fine grain metal sheet and preparation method - Google Patents

Bidirectional extrusion die for preparing ultra-fine grain metal sheet and preparation method Download PDF

Info

Publication number
CN113145675B
CN113145675B CN202011540976.XA CN202011540976A CN113145675B CN 113145675 B CN113145675 B CN 113145675B CN 202011540976 A CN202011540976 A CN 202011540976A CN 113145675 B CN113145675 B CN 113145675B
Authority
CN
China
Prior art keywords
channel
workpiece
die
plate die
main plate
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.)
Active
Application number
CN202011540976.XA
Other languages
Chinese (zh)
Other versions
CN113145675A (en
Inventor
陈海涛
邹银辉
邓文君
周子涵
李松青
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.)
South China University of Technology SCUT
Original Assignee
South China University of Technology SCUT
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 South China University of Technology SCUT filed Critical South China University of Technology SCUT
Priority to CN202011540976.XA priority Critical patent/CN113145675B/en
Publication of CN113145675A publication Critical patent/CN113145675A/en
Application granted granted Critical
Publication of CN113145675B publication Critical patent/CN113145675B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C23/00—Extruding metal; Impact extrusion
    • B21C23/002—Extruding materials of special alloys so far as the composition of the alloy requires or permits special extruding methods of sequences
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C23/00—Extruding metal; Impact extrusion
    • B21C23/02—Making uncoated products
    • B21C23/03—Making uncoated products by both direct and backward extrusion
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C25/00—Profiling tools for metal extruding
    • B21C25/02—Dies
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C26/00—Rams or plungers; Discs therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C29/00—Cooling or heating work or parts of the extrusion press; Gas treatment of work
    • B21C29/003—Cooling or heating of work
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C31/00—Control devices, e.g. for regulating the pressing speed or temperature of metal; Measuring devices, e.g. for temperature of metal, combined with or specially adapted for use in connection with extrusion presses
    • 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/25—Process efficiency

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Extrusion Of Metal (AREA)

Abstract

The invention discloses a bidirectional extrusion die for preparing an ultra-fine grain metal sheet and a preparation method thereof. The die comprises a main plate die, an auxiliary plate die detachably connected with the main plate die, a positive pressure ejector rod, a back pressure ejector rod, an extrusion block, a main knocking rod, a supporting block and an auxiliary knocking rod, a first channel capable of accommodating a workpiece to be machined to move is arranged on the inner side surface of the main plate die in a concave mode along the length direction of the main plate die, a second channel communicated with the first channel is arranged on one side of the main plate die in a concave mode along the width direction of the main plate die and located on the first channel, the positive pressure ejector rod and the back pressure ejector rod are oppositely arranged at two ends of the first channel and can move in the first channel to apply pressure to two ends of the workpiece to be machined, the extrusion block is located on the inner side of the main plate die and close to the first channel and the second channel, the main knocking rod is used for taking out the extrusion block from the main plate die, and the auxiliary knocking rod can be in contact with the workpiece to take out the workpiece. The invention has simple structure and can prepare the ultrafine crystal metal sheet with uniform gradient distribution.

Description

Bidirectional extrusion die for preparing ultra-fine grain metal sheet and preparation method
Technical Field
The invention relates to the technical field of plastic flow processing of metal materials, in particular to a bidirectional extrusion die for preparing an ultra-fine grain metal sheet and a preparation method thereof.
Background
With the continuous improvement of the industrial technology, the requirements on the performance of the metal material are also higher and higher. The ultra-fine grain nano-crystalline material has excellent mechanical, chemical and physical properties due to fine grains, high dislocation density and defect density, but as the strength and hardness of the ultra-fine grain material increase, the toughness and plasticity of the ultra-fine grain material are significantly reduced, the work hardening capacity disappears, and the structural stability is deteriorated, and the defects further limit the application and development of the ultra-fine grain material. Research in recent years shows that the superfine crystal material with the gradient structure has high strength and high plasticity. The gradient structure means that the surface of the superfine crystal material is of a superfine crystal structure, the inside of the superfine crystal material is of coarse crystals, and the size of crystal grains is reduced in a gradient manner from the surface of the material to the inside of the material. The region with the finest grains experiences the greatest accumulated strain and is therefore the highest in mechanical strength; the deformation degree of the area with the thicker and larger grain area is not so large, so the processing hardening degree is not high, and the area can be further deformed, the unique structure of the gradient structure material enables the material to have high strength and good plasticity at the same time, and the problem that the strength and the plasticity of the superfine grain nanocrystalline material are not compatible with each other is solved, so the material has wide research in the disciplines of tribology, biomechanics, fracture mechanics, nanotechnology and the like.
In recent years, many researchers have conducted many studies on how to prepare gradient nano-metal materials with high efficiency and high quality. Aoudia et al (Coatings, 2018,8 (12), 1344-1355) used a nickel-chromium coating deposited on a metal press surface with a Surface Mechanical Abrasion Treatment (SMAT) to prepare a gradient structure. However, the coating has many pores and defects inside, which adversely affect the mechanical properties of the material. H.Y Ma et al (Materials Letters,159, 185-188) applied electrodeposition technology to carbon nanotubes produced gradient structures with grain sizes ranging from 20 to 425000nm, the process was complex, and the thickness of the produced gradient structures was not easily controlled, resulting in no significant gradient distribution of internal grain sizes. The Chinese invention patent (CN 105821180A) provides a method for constructing a gradient structure on the surface of a metal material, the method uses a continuous laser to carry out laser heat treatment on the surface of the metal material, the size of fine grains prepared by the method is 5-10um, and the size range of ultra-fine grains is not reached, so that the further improvement of the mechanical property of the material is limited.
Therefore, the method has the problems that the material with the gradient structure has internal defects, the prepared gradient structure is not easy to control, the size of the prepared fine crystal grains cannot reach the superfine crystal standard and the like, and the application of the material with the gradient structure is limited.
Disclosure of Invention
In view of solving the above problems, a first object of the present invention is to provide a bi-directional extrusion die for manufacturing an ultra-fine grained metal sheet having a gradient structure, which is simple in structure, low in cost, and capable of manufacturing a gradient structure material having a uniform gradient distribution.
Another object of the present invention is to provide a method of manufacturing an ultra-fine grained metal sheet.
In order to achieve the purpose, the scheme of the invention is realized by the following technical scheme:
a bidirectional extrusion die for preparing an ultra-fine grain metal sheet with a gradient structure comprises a main plate die, an auxiliary plate die detachably connected with the main plate die, a positive pressure ejector rod, a back pressure ejector rod, an extrusion block, a main knock rod, a supporting block and an auxiliary knock rod,
a first channel which can accommodate the workpiece to be processed to move is concavely arranged on the inner side surface of the main plate die, which is contacted with the auxiliary plate die, along the length direction of the main plate die, the length of the first channel is equal to that of the main plate die, a second channel which is communicated with the first channel is concavely arranged along the width direction of the main plate die and positioned on one side of the first channel, a positive pressure ejector rod and a negative pressure ejector rod are oppositely arranged at two ends of the first channel and can move in the first channel to apply pressure to two ends of the workpiece to be processed,
the extrusion block is positioned at the inner side of the main plate die and is arranged close to the first channel and the second channel, one side of the extrusion block close to the first channel extends into the first channel,
the main knock bar is used for taking the extrusion block out of the main plate die,
the auxiliary knock bar can be brought into contact with the workpiece to take out the workpiece.
Furthermore, a chamfer is arranged at the upper left corner of the extrusion block. The chamfer angle determines the angle of the machined workpiece, and the chamfer height determines the thickness of the machined workpiece. The workpiece to be processed moves downwards under the combined action of the positive pressure ejector rod and the negative pressure ejector rod to contact with the chamfer of the extrusion block and generate shearing deformation, and one part of the workpiece is prepared into an ultra-fine crystal thin plate with a gradient structure. On one hand, the chamfer is formed, so that the workpiece to be processed can be conveniently sheared, and the stress condition of the extrusion block is changed so as to reduce the probability of damage of the extrusion block. On the other hand, by arranging the chamfer angle on the extrusion block, the superfine crystal thin plate with different gradients can be prepared by changing the parameters of the chamfer angle.
Furthermore, the width of the extrusion block is 16.5-17.5mm, the height of the extrusion block is 18-20mm, the angle of the chamfer on the extrusion block is 10-80 degrees, and the height of the chamfer is 1-3mm.
Furthermore, an extrusion block clamping opening is formed below the second channel and close to the first channel, and the extrusion block is clamped in the extrusion block clamping opening. The arrangement mode of the extrusion block can facilitate the installation and the replacement of the extrusion block.
Further, the device also comprises a supporting block,
a supporting block clamping groove is arranged on the main plate die and positioned at the inner side of the extrusion block clamping opening, a main knock bar jack communicated with the supporting block clamping groove is inwards arranged on the outer side surface of the main plate die,
the supporting block is clamped and fixed in the supporting block clamping groove, and the main knocking rod can be in contact with the supporting block through the main knocking rod insertion hole.
Through setting up the supporting shoe, with main knock bar contact supporting shoe to strike, strike power and transmit the extrusion piece through the supporting shoe, be convenient for follow-up take out the work piece. And the supporting block transmits the striking force to the extrusion block, so that the extrusion block can be prevented from being damaged due to direct striking of the extrusion block.
Furthermore, an auxiliary rapping bar insertion hole is formed in the main plate die and located at the first channel, the auxiliary rapping bar insertion hole penetrates through the main plate die from the thickness direction, and the auxiliary rapping bar can be inserted into the auxiliary rapping bar insertion hole from the outer side face of the main plate die inwards to be in contact with a workpiece.
Through setting up vice rapping bar jack, vice rapping bar can insert vice rapping bar jack and contact with the work piece, beats vice rapping bar, and the power of beating is transmitted the work piece, is convenient for take out the work piece.
Further, the second channel comprises a horizontal section and a slope section,
the left end of the horizontal section is close to the first channel, and the right end of the horizontal section inclines towards the upper end and the lower end to form the inclined section. This is provided to reduce friction with the ultra-fine grained thin plate having a gradient structure.
A manufacturing method of a bidirectional extrusion die for manufacturing an ultra-fine grained metal sheet with a gradient structure, the bidirectional extrusion die being driven by a hydraulic machine, the bidirectional extrusion die being fixed on a stage of the hydraulic machine through a mounting base, the hydraulic machine including an upper punch and a lower punch, the manufacturing method comprising:
1) Carrying out heat treatment on the main plate die, the auxiliary plate die, the positive pressure ejector rod and the back pressure ejector rod;
2) Fixing the extrusion block and the supporting block on the main plate die, placing a workpiece to be processed into a first channel of the main plate die, contacting the workpiece to be processed with the extrusion block, and fixing the main plate die and the auxiliary plate die by bolts and nuts to form a combined die;
3) Placing the combined mould on an objective table of a hydraulic press, and fixing the combined mould through a mounting seat, a bolt and a nut;
4) Inserting the bottom end of the positive pressure ejector rod into the first channel from the upper part of the combined die, inserting the counter pressure ejector rod into the first channel from the lower part of the combined die, and tightly contacting an upper punch of the hydraulic press with the top end of the positive pressure ejector rod and tightly contacting a lower punch with the bottom end of the counter pressure ejector rod;
5) Setting the pressure of an upper punch and the pressure of a lower punch, wherein the pressure of the upper punch is greater than the pressure of the lower punch; starting a hydraulic machine, enabling an upper punch to move downwards and act on a positive pressure ejector rod, enabling the positive pressure ejector rod to apply a vertically downward pressure to a workpiece to be machined, enabling a lower punch to move upwards and act on a negative pressure ejector rod, enabling the negative pressure ejector rod to apply a vertically upward pressure to the workpiece to be machined, enabling the workpiece to be machined to move downwards from top to bottom along a first channel under the action of the two pressures and to be in contact with an extrusion block to generate shearing deformation, enabling part of materials on the workpiece to be machined to be separated from the workpiece to be machined, enter a second channel and flow horizontally in the second channel, and finally manufacturing an ultrafine crystal sheet with a gradient mechanism due to strain applied by the extrusion block;
6) And closing the hydraulic press, pulling out the positive pressure ejector rod and the negative pressure ejector rod, loosening bolts and nuts for fixing the main plate die and the auxiliary plate die, taking down the auxiliary plate die, inserting one end of the main knocking rod into the main knocking rod insertion hole to be connected with the supporting block, inserting one end of the auxiliary knocking rod into the auxiliary knocking rod insertion hole, and knocking the main knocking rod and the auxiliary knocking rod to take down the processed workpiece.
Further, the workpiece is annealed before the performing step.
Further, the material of the workpiece to be processed is a ductile metal such as copper and aluminum.
Furthermore, the pressure range of an upper punch of the hydraulic press is 100MPa < the pressure of the upper punch is less than or equal to 200MPa, and the pressure of a lower punch is set to be 100MPa. The bidirectional extrusion respectively applies different pressures to the positive pressure ejector rod and the back pressure ejector rod, the pressure applied to the positive pressure ejector rod is greater than that applied to the back pressure ejector rod, the workpiece to be processed can be guaranteed to be stably sheared and deformed under the action of the pressure difference between two ends of the workpiece to be processed, and the superfine crystal thin plate with a large gradient structure layer thickness and uniform gradient distribution is prepared.
Compared with the prior art, the invention has the following beneficial effects:
(1) The invention fully utilizes the plastic deformation performance of metal, so that a workpiece to be processed is contacted with the extrusion block when moving downwards to be extruded and sheared to form an ultra-fine grain material, and the ultra-fine grain material enters the second channel after being separated from the workpiece and flows in the second channel to form an ultra-fine grain thin plate.
(2) In the invention, the extrusion block shears the workpiece to form the ultra-fine grain material, and larger strain is applied to one side of the separated ultra-fine grain material, which is contacted with the extrusion block, and the strain applied to the ultra-fine grain material by the horizontal flow and the friction of the second channel is smaller, so the grain size of the ultra-fine grain metal sheet prepared by the invention is distributed relatively regularly on the surface parallel to the extrusion block, and the grain size is distributed in a gradient manner along the width direction of the surface.
(3) In the invention, the grain size of the workpiece to be processed, which is in contact with the extrusion block, is 100-500nm grade ultrafine crystal, so that the strength of the material is greatly improved; and the grain size of the other side of the workpiece to be processed is in the level of 1-5um, so that the workpiece has the capability of further deformation. The gradient structure enables the superfine crystal material to have high strength and high plasticity.
(4) The bidirectional extrusion applied by the invention can ensure that the process of shearing deformation of the workpiece to be processed in contact with the extrusion block is carried out stably, more workpiece materials are converted into the superfine crystal thin plate with the gradient structure, and the utilization rate of the workpiece is increased.
(5) The invention is suitable for wide range of workpiece materials, and can be block-shaped tough metals such as copper, aluminum, iron, steel and the like.
(6) In the invention, the extrusion block is convenient to install, the angle of the processed workpiece, the thickness of the processed workpiece and the thickness of the prepared superfine crystal thin plate can be changed by replacing the extrusion blocks with different chamfer angles, heights and widths, and the operation is flexible.
Drawings
Fig. 1 is a schematic structural diagram of a bidirectional extrusion die provided by the present invention.
Fig. 2 is an exploded view of the bi-directional extrusion die of the present invention.
Fig. 3 is a schematic view of the process of the present invention.
FIG. 4 is a schematic view of an ultra-fine grained metal sheet with a gradient structure according to the present invention.
Labeled as: 1: a main plate mold 1-1: a first channel 1-2: a second channel, 1-3: a groove, 1-4: an extrusion block clamping port, 1-5: auxiliary tapping rod jack, 1-6: main tapping rod jack, 2: auxiliary plate mold, 3: extrusion block, 4: a supporting block, 5: main tapping rod, 6: auxiliary knock bar, 7: positive pressure ejector rod, 8: back pressure mandril, 9: workpiece to be processed, 10: bolt, 11: nut, 12: and (7) mounting a seat.
Detailed Description
Preferred embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.
Example 1
As shown in fig. 1 and 2, the present example discloses a bi-directional extrusion die for preparing an ultra-fine grained metal thin plate with a gradient structure, which is composed of a main plate die 1, a sub-plate die 2, an extrusion block 3, a support block 4, a main knock bar 5, a sub-knock bar 6, a positive ejector pin 7 and a negative ejector pin 8.
The bottom of the outer side face of the main plate die 1 and the bottom of the outer side face of the auxiliary plate die 2 are respectively fixedly provided with an L-shaped mounting seat 12, the mounting seat 12 is provided with a bolt hole, and during preparation, the main plate die 1 and the auxiliary plate die 2 can be fixed on a hydraulic machine by matching bolt nuts with the bolt holes. First mounting hole has all been seted up to four edges of mainboard mould 1, correspond on the auxiliary board mould 2 seted up with four second mounting holes, mainboard mould 1 and auxiliary board mould 2 realize dismantling the connection through bolt and nut and first mounting hole and second mounting hole cooperation. When the die is assembled, the four first mounting holes and the four second mounting holes are respectively opposite one to one, bolts are respectively inserted, and nuts are adopted for fastening, so that the main plate die 1 and the auxiliary plate die 2 can be fixed.
The inner side face, which is in contact with the auxiliary plate die 2, of the main plate die 1 is provided with a first channel 1-1 which can accommodate a workpiece 9 to be processed to move in a concave mode along the length direction of the main plate die 1, the first channel 1-1 transversely penetrates through the main plate die 1 from the length direction, and a second channel 1-2 which is communicated with the first channel 1-1 is arranged in a concave mode along the width direction of the main plate die 1 and located on the right side of the first channel 1-1. The first channel is used for installing a positive pressure ejector rod 7 and a negative pressure ejector rod 8 and placing a workpiece 9 to be processed, and the second channel is used for preparing an ultrafine crystal thin plate with a gradient structure. The positive pressure mandril 7 and the negative pressure mandril 8 are oppositely arranged at two ends of the first channel 1-1 and can move in the first channel 1-1 so as to apply pressure to two ends of a workpiece 9 to be processed.
The cross section of the first channel is square, the side length variation range is 11-21mm, and the length of the first channel is 140mm. The workpiece 9 to be processed is in a rectangular strip shape, the cross section of the workpiece is square, the side length variation range is 10-20mm, and the length of the blank to be processed is 80-100mm.
Referring to fig. 3, the second channel 1-2 includes a horizontal section and a slope section, the left end of the horizontal section is close to the first channel 1-1, and the right end of the horizontal section is inclined towards the upper and lower ends to form the inclined section. The length of the horizontal section is 4mm, and L1 in fig. 3 represents the length of the horizontal section. 4mm is a reasonable value, the horizontal section with the length of 4mm is enough to enable the ultra-fine grained thin plate to flow horizontally, if the horizontal section is too long, the friction degree between the extruded ultra-fine grained thin plate and the horizontal section is intensified to influence the performance of the ultra-fine grained thin plate, therefore, two sides of the rest part of the second channel are processed into slope structures, and the slope structures play a role in reducing the friction between the ultra-fine grained thin plate and the second channel. The separated workpiece portion flowing out from the horizontal section will not flow in a deflected manner without any external force, and finally the ultra-fine grained metal sheet as shown in fig. 4 can be formed (the right part of the chain line in fig. 4 is the finally manufactured ultra-fine grained metal sheet).
FIG. 3 shows the machining principle of the invention and the reference numerals of the key parameters, where P f Setting the pressure for the upper punch, P b Setting the pressure, W, for the lower punch e To squeeze the block width, H e And the length of the extrusion block, w is the chamfering height of the extrusion block, phi is the chamfering angle of the extrusion block, and h is the width of the horizontal part of the second channel.
Referring to fig. 2, the extrusion block 3 is located inside the main plate die 1 and is disposed adjacent to the first passage 1-1 and the second passage 1-2. In the embodiment, an extrusion block clamping opening 1-4 is formed in the inner side of the main board die 1 and below the intersection of the first channel 1-1 and the second channel 1-2 for clamping and fixing the extrusion block 3. When the workpiece to be processed moves from top to bottom in the first channel 1-1, the workpiece to be processed is contacted with the extrusion block 3, and the workpiece to be processed is subjected to shear deformation. In the embodiment, a chamfer angle is formed at the upper left corner of the extrusion block 3, the chamfer angle of the extrusion block is 60 degrees, the chamfer height is 2mm, the width of the extrusion block is 16.6mm, and an ultrafine crystal thin plate with the width of 1.4mm can be prepared. By arranging the chamfer, the probability of damage of the extrusion block can be reduced, and the ultra-fine crystal thin plates with different sizes can be prepared by changing the parameters of the chamfer, namely the angle, the height and the like of the chamfer. In the present embodiment, the first and second electrodes are,
a supporting block clamping groove 1-3 is formed in the main plate die 1 and located on the inner side of the extrusion block clamping opening 1-4, a main knock bar inserting hole 1-6 communicated with the supporting block clamping groove 1-3 is formed in the outer side face of the main plate die 1 inwards, the supporting block 4 is clamped and fixed in the supporting block clamping groove 1-3, and the main knock bar 5 can be in contact with the supporting block 4 through the main knock bar inserting hole 1-6. An auxiliary knock bar inserting hole 1-5 is formed in the main plate die 1 and located at the first channel 1-1, the auxiliary knock bar inserting hole 1-5 penetrates through the main plate die 1 from the thickness direction, and the auxiliary knock bar 6 can be inserted into the auxiliary knock bar inserting hole 1-5 from the outer side face of the main plate die 1 inwards to be in contact with a workpiece.
The workpiece is easy to flow laterally in the extrusion processing process so as to be blocked in the channel, the workpiece can be tightly contacted with the extrusion block and is difficult to separate, and the extrusion block or the workpiece is difficult to take out. In order to take out the workpiece better, a main knocking rod and an auxiliary knocking rod are arranged, and the workpiece is knocked out from the side surface. Specifically, one end of a main knock rod 5 abuts against the supporting block 4 through the main knock rod insertion holes 1-6, the main knock rod 5 is knocked, and the hitting force is transmitted to the extrusion block 3 through the supporting block 4, so that the extrusion block 3 can be easily taken out. One end of the auxiliary knocking rod 6 is abutted against the workpiece through the auxiliary knocking rod insertion holes 1-5, and the auxiliary knocking rod 6 is knocked to apply force to the workpiece, so that the workpiece can be taken out easily.
In this embodiment, the main plate die 1, the sub plate die 2, and the extrusion block 3 are made of Cr12MoV.
When the bidirectional extrusion die provided by the embodiment is used for preparation, the main plate die 1 and the auxiliary plate die 2 are fixed on an object stage of a four-column hydraulic machine through the mounting seat 12, the bottom end of the positive pressure ejector rod 7 is inserted into the first channel 1-1 from the upper part, the reverse pressure ejector rod 8 is inserted into the first channel 1-1 from the lower part, a workpiece 9 to be processed is placed in the first channel 1-1 and is positioned between the positive pressure ejector rod 7 and the reverse pressure ejector rod 8, an upper punch of the four-column hydraulic machine is contacted with the top end of the positive pressure ejector rod 7 and applies downward pressure to the positive pressure ejector rod 7, the positive pressure ejector rod 7 applies force to the workpiece to be processed, a lower punch is contacted with the bottom end of the reverse pressure ejector rod 8 and applies upward pressure to the reverse pressure ejector rod 8, the reverse pressure ejector rod 8 applies force to the workpiece, the workpiece to be processed because the force applied by the upper punch is larger than the force applied by the lower punch, the workpiece to be processed moves downwards in the first channel, the workpiece to be processed in the chamfer of the extrusion block 3 in the moving process, the workpiece to be processed, the superfine crystal material flows in the second channel 1-2, and finally flows along the second channel.
The extrusion block of the embodiment shears the workpiece to form the metal sheet, one side of the ultra-fine grain sheet, which is in contact with the extrusion block, can generate relatively large strain, and the prepared ultra-fine grain material has uniform gradient structure distribution, high Vickers hardness and good tensile property. The invention has simple and convenient processing technology, low cost and easy industrialization.
Example 2
The embodiment provides a method for preparing an ultra-fine grained metal sheet by using the bidirectional extrusion die provided in embodiment 1, where the bidirectional extrusion die is fixed on an object stage of a hydraulic press by a mounting seat, the bidirectional extrusion die is driven by the hydraulic press, the hydraulic press includes an upper punch and a lower punch, and the specific preparation method includes:
(1) And treating the workpiece to be processed, heating the workpiece to be processed 9 at 340 ℃ for 3 hours, then quickly taking out the workpiece to be processed 9 from the muffle furnace, and air-cooling. Annealing the workpiece to be processed to make the internal structure uniform, and eliminating the stress structure defect and residual stress in the workpiece to be processed so as to improve the processability of the workpiece.
(2) Processing the die, namely quenching the main plate die 1, the auxiliary plate die 2, the positive pressure ejector rod 7 and the negative pressure ejector rod 8, heating the materials at 650 ℃ for 2 hours, at 850 ℃ for 2 hours and at 1030 ℃ for 1.5 hours in sequence, and cooling the materials with oil; and tempering the main plate die 1, the auxiliary plate die 2, the positive pressure ejector rod 7 and the negative pressure ejector rod 8, heating the materials at 180 ℃ for 6 hours, taking the materials out of a muffle furnace, cooling in air, and repeatedly tempering until the Rockwell hardness of the materials reaches 60. The main plate die, the auxiliary plate die, the positive pressure ejector rod and the negative pressure ejector rod are subjected to heat treatment, so that the mechanical properties of the main plate die, the auxiliary plate die, the positive pressure ejector rod and the negative pressure ejector rod are improved, and the failure phenomena of bending of the positive pressure ejector rod and the negative pressure ejector rod, cracking of the main plate die and the auxiliary plate die and the like in machining are avoided.
(3) Sequentially installing a supporting block 4 and an extrusion block 3 on a main board die 1, putting a workpiece 9 to be processed which is processed to a required size into a first channel 1-1 of the main board die 1, and enabling the workpiece to be processed to be just contacted with the extrusion block 8; the main plate die 1 and the sub plate die 2 are fixed with hexagon socket head cap bolts 10 and nuts 11 to form a combined die.
(4) The combined die is placed on an objective table of a four-column hydraulic press, and is fixed through the mounting base 12 and the bolts and nuts.
(5) The bottom end of the positive pressure ejector rod 7 is inserted into the first channel 1-1 from the upper part of the combined die, the counter pressure ejector rod 8 is inserted into the first channel 1-1 from the lower part of the combined die, an upper punch of the hydraulic press is tightly contacted with the top end of the positive pressure ejector rod 7, and a lower punch is tightly contacted with the bottom end of the counter pressure ejector rod 8.
(6) Setting the working pressure of the upper punch and the lower punch, wherein the pressure of the upper punch is greater than that of the lower punch, and forming pressure difference at two ends of the workpiece, so that the workpiece is stably subjected to shear deformation, and the success rate and the conversion rate of preparing the ultra-fine grain thin plate are improved; starting the four-column hydraulic machine to enable the upper punch to move downwards and act on the positive pressure ejector rod 7, and enabling the positive pressure ejector rod 7 to act on the upper end of the workpiece 9 to be processed to generate a vertically downward pressure; meanwhile, the lower punch acts on the back pressure ejector rod 8, and the back pressure ejector rod 8 acts on the lower end of the workpiece 9 to be processed to enable the workpiece to generate a vertically upward pressure. The pressure borne by the upper end of the workpiece 9 to be processed is larger than the pressure borne by the lower end, under the action of the pressure difference between the two ends, the workpiece 9 to be processed stably moves vertically downwards and generates shear deformation, a part of materials are separated from the workpiece 9 and horizontally flow in the second channel vertical to the first channel, and meanwhile, the side, acting on the extrusion block, of the part of materials is subjected to strain exerted by the extrusion block 3, and finally the superfine crystal thin plate with the gradient structure is formed.
(7) Closing a switch of the four-column hydraulic machine, removing pressure at two ends of an extrusion die, pulling out a positive pressure ejector rod 7 and a negative pressure ejector rod 8, loosening bolts and nuts for fixing a main plate die 1 and an auxiliary plate die 2, taking off the auxiliary plate die 2, installing a main knock bar 5 in a main knock bar insertion hole 1-6 of the main plate die 1, enabling one end of the main knock bar 5 to be in contact with a supporting block 4, inserting one end of an auxiliary knock bar 6 into an auxiliary knock bar insertion hole 1-5, enabling one end of the auxiliary knock bar 6 to be in contact with a workpiece, and knocking the main knock bar 5 and the auxiliary knock bar 6 by a hammer to take out the rest workpiece and the superfine crystal thin plate. The horizontal portion of fig. 4, which is located at the right side of the center line, is the desired ultra-fine grained metal sheet with a gradient structure, and the size of the ultra-fine grained metal sheet is 20mm × 10mm × 1.4mm. During the processing, the part is sheared and separated and smoothly flows in the second channel, and a thin plate with a flat surface and no cracks is formed. Tests show that the average grain size of one side of the gradient material, which is in contact with the extrusion block, is about 400nm to reach the ultra-fine grain level, the average grain size of the other side of the gradient material is about 3 mu m, and the gradient structure is uniformly distributed. The average Vickers hardness of the ultrafine grain thin plate was 48HV, and the elongation thereof was 5%.
In this embodiment, the first passage 1-1 of the master die is lubricated with a general-purpose cutting oil.
During preparation, lubricating oil can be added to the workpiece to be processed and the extrusion block so as to prevent the workpiece to be processed from being blocked and improve the processability of the material.
The material of the workpiece 9 to be processed is any one of tough metals such as copper, aluminum, iron, steel and the like. In this embodiment, the workpiece to be processed is made of pure aluminum 1010, the cross-sectional dimension of the workpiece is 10mm × 10mm, and the length of the workpiece is 80mm.
In this embodiment, the working pressure of the upper punch was set to 150Mpa, and the working pressure of the lower punch was set to 100Mpa.
The above-mentioned embodiment is only one embodiment of the present invention, but the embodiment of the present invention is not limited by the above-mentioned embodiment. It should be understood that any other changes, modifications, substitutions, combinations and simplifications which do not depart from the spirit and principle of the invention should be construed as equivalents thereof and are included in the scope of the invention.

Claims (9)

1. A bidirectional extrusion die for preparing an ultra-fine grain metal sheet is characterized in that: comprises a main plate die (1), an auxiliary plate die (2) detachably connected with the main plate die (1), a positive pressure ejector rod (7), a back pressure ejector rod (8), an extrusion block (3), a main knock bar (5), a supporting block (4) and an auxiliary knock bar (6),
a first channel (1-1) which can accommodate a workpiece (9) to be processed to move is concavely arranged on the inner side surface of the main plate die (1) which is contacted with the auxiliary plate die (2) along the length direction of the main plate die (1), the length of the first channel (1-1) is equal to that of the main plate die (1), a second channel (1-2) which is communicated with the first channel (1-1) is concavely arranged on one side of the first channel (1-1) along the width direction of the main plate die (1), a positive pressure ejector rod (7) and a back pressure ejector rod (8) are oppositely arranged at two ends of the first channel (1-1) and can move in the first channel (1-1) to apply pressure to two ends of the workpiece (9) to be processed,
the extrusion block (3) is positioned at the inner side of the main plate die (1) and is arranged close to the first channel (1-1) and the second channel (1-2), one side of the extrusion block (3) close to the first channel (1-1) extends into the first channel (1-1),
the main knocking rod (5) is used for taking the extrusion block (3) out of the main plate die (1),
the auxiliary knocking rod (6) can be in contact with the workpiece to take the workpiece out; a supporting block clamping groove (1-3) is arranged on the main board die (1) and positioned at the inner side of the extrusion block clamping opening (1-4), a main knock bar jack (1-6) communicated with the supporting block clamping groove (1-3) is inwards arranged on the outer side surface of the main board die (1),
the supporting block (4) is clamped and fixed in the supporting block clamping grooves (1-3), and the main knocking rod (5) can be in contact with the supporting block (4) through the main knocking rod insertion holes (1-6); an auxiliary rapping bar jack (1-5) is formed in the main plate die (1) and located at the first channel (1-1), the auxiliary rapping bar jack (1-5) penetrates through the main plate die (1) from the thickness direction, and the auxiliary rapping bar (6) can be inserted into the auxiliary rapping bar jack (1-5) from the outer side face of the main plate die (1) inwards to be in contact with a workpiece.
2. The bi-directional extrusion die for manufacturing ultra-fine grained metal sheet as claimed in claim 1, wherein: the left upper corner of the extrusion block (3) is provided with a chamfer.
3. The bi-directional extrusion die for manufacturing ultra-fine grained metal sheet as claimed in claim 1, wherein: the width of the extrusion block is 16.5-17.5mm, the height of the extrusion block is 18-20mm, the thickness of the extrusion block is 11-21mm, the angle of the chamfer on the extrusion block is 10-80 degrees, and the height of the chamfer is 1-3mm.
4. The bi-directional extrusion die of claim 1, wherein: an extrusion block clamping opening (1-4) is formed below the second channel (1-2) and close to the first channel (1-1), and the extrusion block (3) is clamped in the extrusion block clamping opening (1-4).
5. The bi-directional extrusion die of claim 1, wherein: the second channel (1-2) comprises a horizontal section and a slope section,
the left end of the horizontal section is close to the first channel (1-1), and the right end of the horizontal section inclines towards the upper end and the lower end to form the slope section.
6. A method for manufacturing an ultra-fine grained metal sheet using the bi-directional extrusion die of any one of claims 1 to 5, characterized in that: fixing the bidirectional extrusion die on a hydraulic press objective table, driving the bidirectional extrusion die through a hydraulic press, wherein the hydraulic press comprises an upper punch and a lower punch, and the preparation method comprises the following steps:
1) Fixing an extrusion block (3) and a supporting block (4) on a main plate die (1), putting a workpiece (9) to be processed into a first channel (1-1) of the main plate die (1), contacting the workpiece (9) to be processed with the extrusion block (3), and fixing the main plate die (1) and an auxiliary plate die (2) by adopting bolts and nuts to form a combined die;
2) Fixing the combined mould on a hydraulic press objective table;
3) Inserting the bottom end of a positive pressure ejector rod (7) into the first channel (1-1) from the upper part of the combined die, inserting a counter pressure ejector rod (8) into the first channel (1-1) from the lower part of the combined die, and tightly contacting an upper punch of a hydraulic machine with the top end of the positive pressure ejector rod (7) and a lower punch with the bottom end of the counter pressure ejector rod (8);
4) Setting the pressure of an upper punch and the pressure of a lower punch, wherein the pressure of the upper punch is greater than the pressure of the lower punch; starting a hydraulic machine, enabling an upper punch to move downwards and act on a positive pressure ejector rod (7), enabling the positive pressure ejector rod (7) to apply a vertically downward pressure to a workpiece (9) to be processed, enabling a lower punch to move upwards and act on a counter pressure ejector rod (8), enabling the counter pressure ejector rod (8) to apply a vertically upward pressure to the workpiece (9) to be processed, enabling the workpiece (9) to be processed to move from top to bottom along a first channel (1-1) and to be in contact with an extrusion block (3) under the action of the two pressures, enabling the workpiece (9) to be processed to be subjected to shearing deformation, enabling partial materials on the workpiece (9) to be processed to be separated from the workpiece (9) to be processed, enter a second channel (1-2) and flow horizontally in the second channel (1-2), and finally forming an ultrafine crystal thin plate with a gradient structure due to strain applied by the extrusion block (3);
5) Closing the hydraulic machine, pulling out the positive pressure ejector rod (7) and the back pressure ejector rod (8), loosening bolts and nuts for fixing the main plate die (1) and the auxiliary plate die (2), taking down the auxiliary plate die (2), inserting one end of the main knocking rod (5) into the main knocking rod insertion holes (1-6) to be in contact with the supporting block (4), inserting one end of the auxiliary knocking rod (6) into the auxiliary knocking rod insertion holes (1-5), and knocking the main knocking rod (5) and the auxiliary knocking rod (6) to take down the machined workpiece.
7. The method of manufacturing according to claim 6, characterized in that: annealing the workpiece before the step 1).
8. The method of manufacturing according to claim 6, characterized in that: the workpiece (9) to be machined is made of copper, aluminum, iron or steel.
9. The method of manufacturing according to claim 6, characterized in that: the pressure range of an upper punch of the hydraulic press is 100MPa < the pressure of the upper punch is less than or equal to 200MPa, and the pressure of a lower punch is set to be 100MPa.
CN202011540976.XA 2020-12-23 2020-12-23 Bidirectional extrusion die for preparing ultra-fine grain metal sheet and preparation method Active CN113145675B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202011540976.XA CN113145675B (en) 2020-12-23 2020-12-23 Bidirectional extrusion die for preparing ultra-fine grain metal sheet and preparation method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202011540976.XA CN113145675B (en) 2020-12-23 2020-12-23 Bidirectional extrusion die for preparing ultra-fine grain metal sheet and preparation method

Publications (2)

Publication Number Publication Date
CN113145675A CN113145675A (en) 2021-07-23
CN113145675B true CN113145675B (en) 2022-12-16

Family

ID=76878014

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202011540976.XA Active CN113145675B (en) 2020-12-23 2020-12-23 Bidirectional extrusion die for preparing ultra-fine grain metal sheet and preparation method

Country Status (1)

Country Link
CN (1) CN113145675B (en)

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3822186B2 (en) * 2003-05-26 2006-09-13 アカマツフォーシス株式会社 Mold for grain refinement
CN102773297B (en) * 2012-07-30 2015-01-28 华南理工大学 Severe plastic deformation method and severe plastic deformation device for pressing and rolling corner of non-equivalent passage
CN103785700B (en) * 2014-01-28 2016-04-13 徐州工程学院 A kind of mould and method preparing ultra-fine crystal block body material
CN103831588A (en) * 2014-02-28 2014-06-04 华南理工大学 Large-strain extruding and cutting preparation method for ultra-fine grain or nanocrystalline metallic material
CN107282671A (en) * 2017-07-21 2017-10-24 合肥工业大学 The blanking type variable cross-section of ultra fine grained steel bar back and forth squeezes and turns round upsetting manufacturing process
CN108380682A (en) * 2018-03-26 2018-08-10 合肥工业大学 A kind of diameter reduced reciprocating extrusion forming method of grain size gradient distribution
CN110026444A (en) * 2019-04-25 2019-07-19 上海工程技术大学 A kind of automation equipment being used to prepare ultrafine grain metal material and control method

Also Published As

Publication number Publication date
CN113145675A (en) 2021-07-23

Similar Documents

Publication Publication Date Title
RU2454292C1 (en) Four-head forging device for forging press
CN102029350B (en) Progressive forging forming method for large cake forged pieces
CN1943899A (en) Pressure variable edge force difference temperature drawing method for magnesium alloy plate
CN102126121B (en) New process combining forging and rolling
CN113145675B (en) Bidirectional extrusion die for preparing ultra-fine grain metal sheet and preparation method
CN113695500A (en) Gear shaft forging process
CN1778487A (en) Bending stretch shaping method and shaper for low-melting point alloy mould
CN109622648B (en) Asymmetric continuous large-deformation extrusion forming method for magnesium alloy
CN104646416A (en) Strong-shear rolling forming method and device for metal plate
CN201353616Y (en) Thermoforming, punching and trimming integrated die of high-strength steel elements
CN109648024A (en) A kind of application method of forging tools convex tup
CN110158000A (en) A method of abatement alloy plate residual stress
CN1556229A (en) Multimedia steel ball automatic quencing machine
CN101486062A (en) Thermoforming and edge-cutting integrated technique and mold of high-duty steel part
CN104772538B (en) Preparation method for copper-aluminum composite micro-electrolysis electrode
CN202438652U (en) Shaping mould for hot extrusion forming of through hole of forging work clamping sheet
CN202411317U (en) Pre-forging mold for forging hot extrusion through hole of working clip
CN207508180U (en) A kind of self-jacking type spine bar hot forged mould
Bhoyar et al. Manufacturing processes part II: a brief review on forging
CN101819118B (en) Wearing characteristics detection die of tool material for steel plate material punching
CN110394606A (en) A kind of aluminum alloy cross beam assembly processing technology
CN213915934U (en) Heavy ton forging seat for end head of large steel bar
CN108754365A (en) A kind of high density twin structure ZK21 magnesium alloy block materials preparation methods
CN220144666U (en) V-shaped anvil block assembly
CN201353618Y (en) Thermoforming and trimming integrated die of high-strength steel elements

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant