CN114507829B - Preparation device and method of aluminum and aluminum alloy plate - Google Patents
Preparation device and method of aluminum and aluminum alloy plate Download PDFInfo
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- CN114507829B CN114507829B CN202210044315.0A CN202210044315A CN114507829B CN 114507829 B CN114507829 B CN 114507829B CN 202210044315 A CN202210044315 A CN 202210044315A CN 114507829 B CN114507829 B CN 114507829B
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- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
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Abstract
The invention relates to a device and a method for preparing aluminum and aluminum alloy plates, which comprises the following steps: limiting the severe plastic deformation of the die pressing on the aluminum and aluminum alloy plates; while limiting the mould pressing deformation process, pulse current is introduced into the aluminum and aluminum alloy plates; synchronously cutting off the pulse current after the deformation is finished; and obtaining the required aluminum and aluminum alloy plates after the final treatment of limiting the severe plastic deformation of the die pressing. In the process of limiting deformation of mould pressing, pulse current is introduced to flow through the whole aluminum and aluminum alloy plate, the pulse current is cut off while the pressure head is lifted after the deformation is finished, then the press bending process and the flattening process of limiting mould pressing are repeated, and the process of multi-pass deformation or cross mould pressing deformation is finished according to the material properties; through the pulse current synchronously flowing in the die pressing process, the grain structure of the aluminum and aluminum alloy plates can be refined after die pressing, and the elongation and the comprehensive mechanical property of the deformed plates are improved.
Description
Technical Field
The invention relates to the technical field of metal processing, in particular to a device and a method for preparing aluminum and aluminum alloy plates.
Background
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
The aluminum and the aluminum alloy have the characteristics of low density, high strength, good plasticity, excellent weldability, electrical conductivity, thermal conductivity and corrosion resistance and no low-temperature brittleness, and the crystal grains can be refined by using a severe plastic deformation method in the production process, so that the strength of the material is improved. And the restrained die-pressing deformation is one of the severe plastic deformation methods, by alternately pressing using a set of asymmetric groove dies and a set of flat dies, theoretically pure shear deformation is uniformly applied to the plate sample, and by repeating this process, an ultra-fine grain structure is obtained without changing the sample size to enhance the properties of the material.
The limitation of the die pressing can effectively refine the grains of the plate and improve the strength, but can cause the problem of reduced plasticity. The reduction of plasticity not only influences the possibility of subsequent limitation of the introduction of larger deformation amount by die pressing, but also influences the further processing performance of the deformed plate.
Disclosure of Invention
Aiming at the aluminum and aluminum alloy plates, in the process of limiting the deformation of the die pressing, pulse current is introduced to flow through the whole plate at the same time, the pulse current is cut off when the pressure head is lifted after the deformation is finished, then the plate is rotated by 180 degrees, the bending process and the flattening process of the die pressing are limited repeatedly, the die pressing is limited to be finished once after the two-time bending and flattening deformation is finished, and the multi-pass deformation or the cross-mode die pressing deformation process is finished according to the material property; through pulse electricity which synchronously flows in the die pressing process, the grain structure of the aluminum and aluminum alloy plates can be refined after die pressing, and the elongation and the comprehensive mechanical property of the deformed plates are improved.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention provides a preparation method of an aluminum and aluminum alloy plate, which comprises the following steps:
limiting the severe plastic deformation of the die pressing on the aluminum and aluminum alloy plates;
while limiting the die pressing deformation process, introducing pulse current to the aluminum and aluminum alloy plates; synchronously cutting off the pulse current after the deformation is finished;
and obtaining the required aluminum and aluminum alloy plates after the final treatment of limiting the severe plastic deformation of the die pressing.
The thickness of the aluminum and aluminum alloy plate is 1-5 mm.
In the process of limiting severe plastic deformation of the mould pressing, the tooth width range of the bending mould of the mould pressing is 1-5 mm, and the tooth height range is 1-5 mm.
The electrical pulse parameters were: pulse width of 90-100 mus, pulse voltage range of 50-90, pulse frequency range of 200-700 Hz, effective current density range of 1-10A/m 2 。
The process for limiting the severe plastic deformation of the die comprises at least one press bending deformation process and at least one flattening deformation process.
And pulse current is introduced into the aluminum and aluminum alloy plates in each bending deformation and flattening deformation process.
After the aluminum and aluminum alloy plates are subjected to bending twice and flattening deformation, the die pressing is limited to be completed in one step.
The second aspect of the invention provides a preparation device for realizing the method, which is a molded plate positioned between an upper die and a lower die, wherein the molded plate is connected with an electrode, the electrode is connected with a pulse power supply, and the molded plate is connected with a temperature sensor.
The upper and lower dies comprise an upper bending die, a lower bending die, an upper flattening die and a lower flattening die.
The oblique teeth on the surfaces of the upper bending die and the lower bending die enable the die-pressed plate to be sheared and deformed, and the upper flattening die and the lower flattening die enable the deformed part of the die-pressed plate to be flattened.
Compared with the prior art, the above one or more technical schemes have the following beneficial effects:
in the deformation process of limiting mould pressing, pulse current is introduced to flow through the whole aluminum and aluminum alloy plate, the pulse current is cut off while the pressure head is lifted after the deformation is finished, then the press bending process and the flattening process of limiting mould pressing are repeated, and the mould pressing deformation process of multi-pass deformation or a cross mode is finished according to the material property; through the pulse current synchronously flowing in the die pressing process, the grain structure of the aluminum and aluminum alloy plates can be refined after die pressing, and the elongation and the comprehensive mechanical property of the deformed plates are improved.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention.
FIG. 1 (a) is a schematic structural diagram of a plate making apparatus according to one or more embodiments of the present invention, when a transverse power is applied;
FIG. 1 (b) is a schematic structural diagram of a plate making apparatus according to one or more embodiments of the present invention, when longitudinal power is applied;
FIG. 2 is a schematic diagram of a structure of an insulation press punch in a sheet preparation apparatus according to one or more embodiments of the present invention;
FIG. 3 is a schematic diagram of a bending die and a flattening die in a sheet preparation apparatus according to one or more embodiments of the present invention;
FIG. 4 is a schematic flow diagram of a conventional parallel restrained sheet material formed by a press according to one or more embodiments of the present invention;
FIG. 5 is a schematic flow chart of a 180 cross-restriction embossing sheet material according to one or more embodiments of the present invention;
FIG. 6 is a schematic flow diagram of a 90 cross-limit sheet material stamping process provided by one or more embodiments of the present invention;
FIG. 7 (a) is a graph of the stress-strain curve of 1060 pure aluminum annealed to form a sheet in accordance with one or more embodiments of the present disclosure;
FIG. 7 (b) is a schematic graph showing the stress-strain curve of a plate obtained after electric pulse assisted restraint die pressing of 1060 pure aluminum according to one or more embodiments of the present invention;
FIG. 8 (a) is a schematic cross-sectional microhardness diagram of a sheet at each pass under different conditions of 1060 run pure aluminum according to one or more embodiments of the present invention;
FIG. 8 (b) is a schematic cross-sectional hardness distribution analysis chart of 1060 pure aluminum in various passes according to one or more embodiments of the present invention;
FIG. 9 (a) is a graph illustrating a stress-strain curve of 6061 aluminum annealed to form a sheet in accordance with one or more embodiments of the invention;
FIG. 9 (b) is a schematic graph of a stress-strain curve of a 6061 aluminum sheet obtained by electric pulse assisted restraint die pressing according to one or more embodiments of the present invention;
FIG. 10 (a) is a schematic cross-sectional microhardness diagram of 6061 aluminum at various passes according to one or more embodiments of the present invention;
FIG. 10 (b) is a schematic diagram of a statistical analysis of the cross-sectional hardness distribution of 6061 aluminum in each pass under different conditions according to one or more embodiments of the present invention;
FIG. 11 is a statistical representation of the range of grain sizes of the sheet under different limiting die pressing conditions, according to one or more embodiments of the present invention;
in FIG. 1 (a): 1. the device comprises a pressure-bearing steel plate, 2 parts of insulating mica, 3 parts of a first conductive copper pole, 4 parts of a die, 5 parts of a temperature measuring point, 6 parts of a guide device, 7 parts of a die pressing plate, 8 parts of a plate fixing device, 9 parts of an insulating layer;
in FIG. 1 (b): 21. PEEK insulation board, 31, baffle, 61, second conductive copper pole, 81, U-shaped restriction groove;
in fig. 2: 10. and the die pressing punch head 11, the nylon bolt 12 and the bakelite.
Detailed Description
The invention is further described with reference to the following figures and examples.
As described in the background art, the limitation of press molding is effective in refining the grains of the sheet and improving the strength, but causes a problem of reduction in plasticity. The reduction of plasticity not only influences the possibility of subsequent limitation of the introduction of larger deformation amount by die pressing, but also influences the further processing performance of the deformed plate.
The high-energy pulse current introduced in the process of processing the metal material is a rapid non-equilibrium process, and electric energy, heat energy and strain energy instantaneously influence the microstructure and the macroscopic property of the metal material. As the application of high-energy external field processing in plastic forming, the high-energy electric pulse auxiliary forming can obviously reduce the deformation resistance of materials, improve the plasticity, improve the structure performance of products, reduce the residual stress of the products, cancel annealing or reduce intermediate annealing, and reduce pores or heal cracks. The research shows that the electric pulse auxiliary forming can improve the surface quality of the workpiece, obviously improve the ultimate tensile strength of the plate, promote the dynamic recrystallization of the alloy and refine grains. The research on the effect of the electric pulse action mainly focuses on promoting atomic diffusion (electromigration), improving the plasticity (electrostrictivity) of the material, or enabling the material to obtain superplasticity (electrostrictivity), and the like, so as to improve the elongation.
Therefore, the following embodiments provide a device and a method for preparing an aluminum and aluminum alloy plate, aiming at the aluminum and aluminum alloy plate, in the deformation process of limiting die pressing, pulse current is introduced to flow through the whole plate at the same time, after the deformation is finished, the pressure head is lifted, and the pulse current is cut off, then the plate is rotated by 180 degrees, the bending process and the flattening process of limiting die pressing are repeated, after the two times of bending and flattening deformation are finished, the limiting die pressing is finished once, and according to the material properties, the multi-pass deformation or the cross mode die pressing deformation process is finished; through pulse electricity which synchronously flows in the die pressing process, the grain structure of the aluminum and aluminum alloy plates can be refined after die pressing, and the elongation and the comprehensive mechanical property of the deformed plates are improved.
The first embodiment is as follows:
as shown in fig. 1 to 11, a method for preparing an aluminum and aluminum alloy plate comprises the following steps:
limiting the severe plastic deformation of the die pressing on the aluminum and aluminum alloy plates;
while limiting the mould pressing deformation process, pulse current is introduced into the aluminum and aluminum alloy plates; synchronously cutting off the pulse current after the deformation is finished;
and obtaining the required aluminum and aluminum alloy plates after the final treatment of limiting the severe plastic deformation of the die pressing.
Specifically, the method comprises the following steps:
the preparation device is shown in fig. 1, and the present example provides two types of electric pulse assisted restriction molding devices, namely, a transverse electric pulse assisted restriction molding device, as shown in fig. 1 (a); a longitudinal electric pulse auxiliary limiting die pressing device, as shown in FIG. 1 (b);
in the experimental process, pulse current needs to be introduced into the plate, and the plate is limited by alternately using bending and flattening dies for die pressing forming. In the process, the current does not pass through a universal testing machine, so that the punch part and the die clamping part are subjected to insulation treatment, and the whole die is prevented from being crushed, and insulation and compression resistance design is needed for some parts.
The design of insulation treatment aims to insulate all parts of the die and ensure that a pulse current forms a loop in the forming process. And secondly, the whole die and the universal testing machine are insulated to ensure the normal operation and personal and property safety of the extrusion process of the testing machine. A plurality of mica sheets or PEEK plates are used for insulating the clamping parts of the upper die, the lower die and the plates so as to ensure the safety of the experiment. And bakelite is adopted for insulation at the lower part of the placement position of the die main body.
The insulating design can ensure that the pulse current flows through the plate. As shown in fig. 1, in the transverse electric die, the pulse current is connected to the conductive copper poles on both sides, the conductive copper poles are connected to the die pressing plate through fixing columns, and the mica plates are used for being partially insulated from the upper die and the lower die, so that the pulse current flows in a single direction only through the plate and not through other components of the die; in the longitudinal power-up die, the positive and negative electrodes of the pulse current are directly connected with the upper die and the lower die, and the PEEK plates are used for insulation around the upper die, the lower die and the die pressing plate, so that the pulse current completely passes through the die pressing plate and does not pass through other assemblies of the die. Through the insulation design, the most efficient auxiliary limit mould pressing process of the pulse current can be realized, the energy loss is reduced, and the optimal effect is achieved.
In the pressure-resistant design, the upper part and the lower part of the bakelite are respectively provided with a pressure-bearing steel plate made of 45 steel to share the pressure applied in a smaller area, so that the use reliability of the die is ensured.
The die pressing punch is characterized in that as shown in figure 2, the lower pressure-bearing part of the extrusion punch is connected with the connecting part of a stretcher through bakelite, and the three parts are connected through bolts made of nylon, so that the insulation effect can be effectively achieved, and the compressive strength can be guaranteed.
The transverse die is a concave block connected with the upper die and a convex block connected with the lower die, and the two blocks are matched to play a role in positioning the die so as to ensure that the tooth profile is not dislocated or deviated in the process of pressing down materials; in the longitudinal die, the upper die and the lower die are limited in four directions by the U-shaped groove and the front limiting baffle and the rear limiting baffle, and only the upper die and the lower die are allowed to move up and down, so that the guiding and positioning effects are achieved.
The upper and lower dies of the two sets of devices are universal, the schematic diagrams of the upper and lower dies are shown in fig. 3, the upper and lower dies are divided into a pair of bending dies and a pair of flattening dies, an asymmetric structure is adopted, cr12MoV die steel materials are selected and subjected to heat treatment to meet the rigidity requirement, and the plate fixing mode, the insulation mode and the connection mode are different.
The lubricant in the mould pressing process is limited to be quick-drying graphite lubricant, because the graphite has good conductivity, the contact failure and the danger caused by the discharge between circuits can be avoided in the process of introducing electric pulses.
Because the extrusion head and the die base are both made of bakelite material, and the bakelite has insufficient rigidity when bearing a large load, the metal plate is subjected to limited die pressing by a press at room temperature by adopting a force control mode.
In the embodiment, the molding process parameters are limited to that the tooth width of a bending die of a molding die is 2mm, the tooth height of the bending die is 2mm, the thickness of a plate is 2mm, the molding speed is 1mm/min, a force control mode is adopted in an experiment, and molding stop conditions are selected according to different materials. And in the experiment 1, the load is stopped and selected to be 100KN, in the experiment 2, the load is stopped and selected to be 200KN, and the testing machine stops descending after the set load is reached.
In this embodiment, the auxiliary electrical pulse parameters are: the pulse width is 90-100 mus, the pulse voltage is 70V, the pulse frequency is 300Hz, and the effective current density is 1.59A/mm < 2 >.
In the experimental process, a thermocouple is connected at a temperature measuring point identified by the figure 1, and a multi-channel temperature measuring instrument is used for temperature monitoring; specifically, a temperature thermocouple is welded on the molded plate, and a multi-channel temperature measuring instrument is used for temperature monitoring.
The method can increase the strength, plasticity and deformation uniformity of the die-pressing plate. Compared with the common parallel limit die pressing, the electric pulse is added to assist forming, so that the die has higher strength, elongation and better deformation uniformity.
The pure aluminum plates and aluminum alloy plates used in this example were commercially available.
The pulse current supply device used in this example was composed of an electro plastic processing apparatus (THDM-1, a product of metals, ltd, hong bridge, black dragon river) and a digital storage oscilloscope (TDS-1002C-EDU, a product of technologies, ltd, tektronix).
When high-energy pulse current is adopted to assist hot extrusion forming, the instantaneous introduction of electric energy, heat energy and strain energy can affect the microstructure and the macroscopic performance of the metal plate, so that the plasticity of the metal plate can be obviously improved, the forming performance can be improved, and the strain uniformity can be improved.
And the positive electrode and the negative electrode of the pulse power supply are connected with the conductive copper electrode, a cable of the positive power supply is led into the Hall sensor, and pulse current parameter information is acquired by using an oscilloscope. The bandwidth and the maximum sampling rate of the digital storage oscilloscope are respectively 100MHz and 1GS/s, and signals can be accurately captured. In the process of an electric pulse auxiliary limit mould pressing experiment, the frequency width, the peak voltage, the effective voltage and other data of pulse current can be accurately read on a digital storage oscilloscope. And welding a thermocouple wire at the middle position of the plate, and monitoring the temperature change of the plate in the forming process by using a multi-channel thermodetector.
Setting test parameters including pressing speed, molding termination condition and the like on the testing machine, starting the pulse current generating device and simultaneously starting molding. Under the action of the die pressing punch, the metal plate is subjected to shearing deformation under the action of the upper bending die and the lower bending die. In the whole deformation process, pulse current flows through the whole plate through the electrodes, the pulse current generating device is immediately closed after the deformation is finished, the stamping head is manually lifted, and then the flattening die is replaced to repeat the step. And then, rotating the plate by 180 degrees, repeating the bending process and the flattening process, limiting the die pressing to be finished once after the two times of bending and flattening deformation are finished, and finishing the multi-pass deformation or cross die pressing deformation process according to the material property.
For convenience of discussion, common parallel-limited embossing is abbreviated as CGP, and electric pulse-assisted-limited embossing is abbreviated as ECGP, the traditional multi-pass limited embossing is marked as-1 and-2, and the cross-limited embossing is marked as-90 or-180 according to different paths. Fig. 4-6 are schematic diagrams of different strain paths of aluminum and aluminum alloy sheets under electrical pulse assisted confining pressure, wherein fig. 4 shows a conventional parallel confinement die, fig. 5 shows a 180 ° cross confinement die, and fig. 6 shows a 90 ° cross confinement die.
Experiment 1:
FIG. 7 shows the stress-strain curve obtained for commercial purity aluminum 1060 by electrical pulse assisted restraint of stamped (transverse) sheet material. The yield strength is respectively increased by 66.69MPa (229%) and 73.67MPa (252%) in 1 pass and 2 passes of common CGP deformation at room temperature; the tensile strength is respectively increased by 29.6MPa (41.2%) and 35.6MPa (49.5%), and compared with the common parallel limit mould pressing, the ECGP has more remarkable strength improvement effect; the elongation rates of the 1 and 2 passes under the electric pulse auxiliary condition are both higher than that of room-temperature die pressing, the elongation rate after the 1 pass of the electric pulse auxiliary die pressing is 11.6%, and the elongation rate after the one pass of the electric pulse auxiliary die pressing is 8.15% at room temperature, and is improved by 41.3%, similarly, the elongation rate under the electric pulse auxiliary die pressing is 14.8% and is improved by 62.6% at room temperature after the 2 passes of die pressing, and compared with the common parallel limit die pressing process, the elongation rate of the deformed plate can be improved under the same deformation pass of the electric pulse auxiliary limit die pressing.
Fig. 8 shows the micro hardness distribution and analysis of the cross section of the plate under different conditions of 1060 pure aluminum, and it can be found that the hardness distribution is more uniform with the accumulation of strain, and the hardness distribution is more uniform with the addition of electric pulse compared with the plate without the electric pulse-assisted die pressing, thus demonstrating that the electric pulse-assisted mode limiting die pressing effectively improves the strain uniformity. According to related researches, electric pulses can reduce dislocation tangle, obtain better strain uniformity, and avoid plasticity reduction caused by overhigh local internal stress after deformation, thereby improving the ductility of the alloy.
Experiment 2:
fig. 9 shows a stress-strain curve obtained by electric pulse-assisted restraint molding (longitudinal direction) of aluminum alloy 6061. The yield strength of the returned plate in the original state is 55.63MPa, the yield strength is improved to 158.15MPa and 166.28MPa after CGP/ECGP deformation in one pass through parallel die pressing, and the yield strength is respectively improved to 171.32MPa and 173.05MPa after GP/ECGP cross die pressing at 180 ℃; after GP/ECGP cross die pressing at 90 ℃, the yield strength is 142.12MPa and 181.11MPa respectively, so that the electric pulse can improve the strength of the plate, and particularly the metal plate can be obviously improved after a complex deformation process. Similarly, the ultimate tensile strength is respectively improved to 170.3MPa, 180.5MPa, 184.9 MPa, 185.8MPa, 149.9MPa and 192.3MPa from the original 128.2MPa through CGP/ECGP parallel die pressing and 180-degree and 90-degree cross die pressing. It should be noted here that after the cross die pressing at room temperature of 90 °, the strength and elongation rate of the cross die pressing are significantly reduced compared with other deformation modes, which may be because the strain accumulation amount in the deformation state is relatively complex, and the defects such as stress concentration and microcracks are more easily generated inside the plate, so that the change of the strength and elongation rate is significantly reduced, but after the electric pulse assisted ECGP 90 ° cross die pressing, the reduction of the elongation rate and strength of the cross die pressing is significantly improved. Compared with room temperature die-pressing plates, the ductility of the plate is improved, and the strength of the plate is also greatly improved. Compared with the room-temperature CGP process, the electric pulse assisted ECGP process has obvious improvement on the elongation of the plate, the elongation of the plate is improved by 5.75% after the plate is subjected to parallel die pressing for 1 pass deformation, the elongation of the plate is improved by 6.6% after the ECGP is subjected to deformation, the elongation of the plate is improved by 53.96% after the plate is subjected to 180-degree cross die pressing for deformation, the elongation of the plate is improved by 5.26% after the plate is subjected to ECGP deformation, the elongation of the plate is improved by 1.78% after the plate is subjected to 90-degree cross die pressing for deformation, the elongation of the plate is improved by 2.64% after the plate is subjected to ECGP deformation for up to 48.3%, and the obvious effect of the electric pulse assistance on the elongation of the plate after the deformation is proved.
Fig. 10 shows the microhardness distribution and statistical analysis of the cross section of the 6061 aluminum alloy under different conditions, and it can be found that the hardness distribution is more uniform along with the accumulation of strain, and the hardness distribution is more uniform along with the addition of electric pulse compared with the non-electric pulse assisted die pressing plate, thereby demonstrating that the electric pulse assisted mode limiting die pressing effectively improves the strain uniformity. The conclusion and the principle are the same, the electric pulse can reduce dislocation tangle, obtain better strain uniformity, and avoid plasticity reduction caused by overhigh local internal stress after deformation, thereby improving the ductility of the alloy.
Fig. 11 shows the statistics of the fraction of the plate grain size under different limited molding conditions, and it can be seen that the fraction of <5 μm grains increases with the increase of molding pass and the accumulation of strain, and the fraction of <5 μm grains further increases with the addition of electric pulse, which indicates that the electric pulse assists in further refining grains under the same plastic deformation, which is consistent with the results obtained from previous studies. According to the Hall-Petch relation, the mechanical property of the ECGP sheet material, particularly the reason of improving the ductility, is explained from the microscopic view by further refining the grain structure.
Example two:
the device for realizing the preparation method comprises a die pressing plate positioned between an upper die and a lower die, wherein the die pressing plate is connected with an electrode, the outer surfaces of the upper die and the lower die are provided with insulating layers, the die pressing plate is connected with a temperature measuring sensor, and the electrode is connected with a pulse power supply.
Preparation apparatus as shown in fig. 1, this example provides two types of electric pulse-assisted restriction molding apparatuses;
as shown in fig. 1 (a), the transverse electric pulse auxiliary limiting die pressing device comprises a die 4 located in the upper space of a pressure-bearing steel plate 1, an insulating layer 9 is arranged on the upper surface of the pressure-bearing steel plate 1, the die 4 comprises an upper die and a lower die (an upper die and a lower die) which are matched with each other, a die pressing plate 7 is located between the upper die and the lower die and fixed by a plate fixing device 8, the upper die and the lower die move under the guidance of a guide device 6, insulating mica 2 is arranged on the outer surfaces of the upper die and the lower die, and a first conductive copper electrode 3 is connected with the die pressing plate 7.
In a transverse power-up die, pulse current is connected into first conductive copper poles 3 on two sides, the first conductive copper poles 3 are connected with a die pressing plate 7 through fixing columns, and are partially insulated from a die 4 (an upper die and a lower die) by using insulating mica 2, so that the pulse current can realize unidirectional circulation and only passes through the plate without passing through other components of the die;
as shown in figure 1 (b), the vertical electric pulse auxiliary limiting die pressing device comprises a die 4 which is positioned in the upper space of a pressure-bearing steel plate 1, an insulating layer 9 is arranged on the upper surface of the pressure-bearing steel plate 1, the die 4 comprises an upper die and a lower die (an upper die and a lower die) which are matched with each other, a die pressing plate 7 is positioned between the upper die and the lower die, temperature measuring points 5 are arranged on the upper die and the lower die, temperature measuring sensors (thermocouples) are welded on the die pressing plate and are connected with a multi-channel thermometer through the temperature measuring points 5 to measure temperature, U-shaped limiting grooves 81 and a baffle plate 31 are arranged on the outer sides of the upper die and the lower die, PEEK insulating plates are arranged on the outer surfaces of the upper die and the lower die, and a second conductive copper electrode 31 is connected with the die pressing plate 7. The upper and lower molds are restricted in four directions by the U-shaped restriction grooves 81 and the front and rear restriction flaps 31, and are allowed to move only up and down, thereby performing a guiding and positioning function.
In a longitudinal electrification mold, the positive and negative poles of the pulse current are directly connected with the mold 4 (an upper mold and a lower mold), and the PEEK plates 21 are used for insulation around the upper mold and the lower mold and the molded plate 7, so that the pulse current completely passes through the molded plate 7 and does not pass through other components of the mold.
Through the insulation design, the most efficient auxiliary limit mould pressing process of the pulse current can be realized, the energy loss is reduced, and the optimal effect is achieved.
As shown in figure 2, the pressure-bearing lower part of the die pressing punch 10 is connected with the connecting part of the drawing machine through bakelite 12, and the bakelite 12 and the connecting part of the drawing machine are connected through nylon bolts 11, so that the die pressing punch can effectively play an insulation role, and the compressive strength can be ensured.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (5)
1. A preparation method of aluminum and aluminum alloy plates is characterized by comprising the following steps: the method comprises the following steps:
limiting the severe plastic deformation of the die pressing on the aluminum and aluminum alloy plates;
while limiting the mould pressing deformation process, pulse current is introduced into the aluminum and aluminum alloy plates; synchronously cutting off the pulse current after the deformation is finished;
obtaining the required aluminum and aluminum alloy plates after the final pass treatment of limiting the severe plastic deformation of the die pressing; the thickness of the aluminum and aluminum alloy plate is 1 to 5mm;
each time of the bending deformation and the flattening deformation process is performed, pulse current is introduced into the aluminum and aluminum alloy plates, and the parameters of the electric pulse are as follows: the pulse width is 90-100 mu s, the pulse voltage range is 50-90V, the pulse frequency range is 200-700Hz, and the effective current density range is 1-10A/m 2 。
2. The method of claim 1, wherein the method comprises the following steps: in the process of limiting severe plastic deformation of the die pressing, the tooth width range of a bending die of the die pressing die is 1-5 mm, and the tooth height range of the bending die is 1-5 mm.
3. The method of claim 1, wherein the method comprises the following steps: the process for limiting the severe plastic deformation of the die pressing comprises at least one press bending deformation process and at least one flattening deformation process.
4. The method of manufacturing an aluminum and aluminum alloy sheet according to claim 1, wherein: after twice bending and flattening deformation, the die pressing is limited to be completed once.
5. An apparatus for implementing the method of any one of claims 1-4, characterized in that: the temperature measuring device comprises a mould pressing plate positioned between an upper mould and a lower mould, wherein the mould pressing plate is connected with an electrode, the electrode is connected with a pulse power supply, and the mould pressing plate is connected with a temperature measuring sensor;
the upper and lower dies comprise an upper bending die, a lower bending die, an upper flattening die and a lower flattening die; the oblique teeth on the surfaces of the upper bending die and the lower bending die enable the molded plate to be sheared and deformed, and the upper flattening die and the lower flattening die enable the deformed part of the molded plate to be flattened.
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| KR100467942B1 (en) * | 2001-06-08 | 2005-01-24 | 김용석 | Method of Fabricating High Strength Ultrafine Grained Aluminum Alloys Plates by Constrained Groove Pressing(CGP) |
| CN101327506A (en) * | 2008-06-20 | 2008-12-24 | 哈尔滨工业大学 | Method for plasticizing and forming TiAl-based sheet alloy caused by electricity |
| CN101623729B (en) * | 2009-07-21 | 2011-09-21 | 清华大学深圳研究生院 | High-efficiency electroplastic punch molding device |
| CN101818268B (en) * | 2010-06-01 | 2011-09-28 | 福州大学 | Preparation method of nanometer twin crystal Cu-Zn alloy material |
| CN102814349A (en) * | 2012-02-22 | 2012-12-12 | 陶艳 | Electro-plasticizing continuous extrusion molding processing technology of high-strength aluminum alloy |
| CN105483588B (en) * | 2015-12-09 | 2017-06-30 | 东北大学 | A kind of preparation method of High-strength pure titanium sheet material |
| CN108372210B (en) * | 2016-12-20 | 2020-10-16 | 中国航空制造技术研究院 | Equal-channel extrusion method |
| CN110479785A (en) * | 2019-09-30 | 2019-11-22 | 吉林大学 | The Equal Channel Angular Pressing device and method of pulse current auxiliary |
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