CN112058985B - Light alloy sheet stamping heat treatment process and stamping device - Google Patents
Light alloy sheet stamping heat treatment process and stamping device Download PDFInfo
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- CN112058985B CN112058985B CN202010739219.9A CN202010739219A CN112058985B CN 112058985 B CN112058985 B CN 112058985B CN 202010739219 A CN202010739219 A CN 202010739219A CN 112058985 B CN112058985 B CN 112058985B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
- B21D22/02—Stamping using rigid devices or tools
- B21D22/022—Stamping using rigid devices or tools by heating the blank or stamping associated with heat treatment
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- 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
- B21C51/00—Measuring, gauging, indicating, counting, or marking devices specially adapted for use in the production or manipulation of material in accordance with subclasses B21B - B21F
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D37/00—Tools as parts of machines covered by this subclass
- B21D37/10—Die sets; Pillar guides
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D37/00—Tools as parts of machines covered by this subclass
- B21D37/16—Heating or cooling
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/0081—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for slabs; for billets
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
- C22F1/002—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working by rapid cooling or quenching; cooling agents used therefor
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
- C22F1/04—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon
Abstract
The invention discloses a light alloy plate stamping heat treatment process and a stamping device, wherein the light alloy plate stamping heat treatment process comprises the following steps: heating the light alloy material to above the solid solution temperature and keeping the heat preservation temperature; acquiring a forming temperature path required by the forming process of the stamping part, and enabling the temperature of the part to change according to the required forming temperature path in the forming process of the part through electric pulses so that the part has a preset stamping organization state; acquiring a cooling temperature path required by the cooling process of the stamping part, and controlling the cooling temperature change of the part according to the forming temperature path and the cooling temperature path so as to enable the part to have a preset cooling structure state; acquiring target strength and current strength of a part; and determining that the current strength is smaller than the target strength, and performing an artificial aging process on the cooled part. The technical scheme of the invention is beneficial to improving the internal tissue state of the part so as to improve the formability and physical properties of the part.
Description
Technical Field
The invention relates to the technical field of stamping forming, in particular to a stamping heat treatment process and a stamping device for a light alloy plate.
Background
With the development of economy, the quality requirements of products on light alloy materials, such as automobile door panels, are increasing. However, in the stamping process of the door panel, the heat treatment of the door panel at each stage cannot be kept in an ideal state, so that the internal organization state of the door panel is poor, and the overall quality of the door is affected.
Disclosure of Invention
The invention mainly aims to provide a stamping heat treatment process for a light alloy plate, which aims to improve the internal structure state of a part so as to improve the formability and physical properties of the part.
In order to achieve the above purpose, the light alloy sheet stamping heat treatment process provided by the invention comprises the following steps:
heating the light alloy material to above the solid solution temperature and keeping the heat preservation temperature;
acquiring a forming temperature path required by the forming process of the stamping part, and enabling the temperature of the part to change according to the required forming temperature path in the forming process of the part through electric pulses so that the part has a preset stamping organization state;
acquiring a cooling temperature path required by the cooling process of the stamping part, and controlling the cooling temperature change of the part according to the forming temperature path and the cooling temperature path so as to enable the part to have a preset cooling structure state; acquiring target strength and current strength of a part;
And determining that the current strength is smaller than the target strength, and performing an artificial aging process on the cooled part.
Optionally, the artificial aging comprises an electric pulse artificial aging first stage and an electric pulse artificial aging second stage, wherein a heat treatment procedure of promoting the nucleation of the GP phase by the electric pulse in the electric pulse artificial aging first stage is applied after the forming, and the workpiece is placed in an aging heating device, and the temperature is lower than the melting temperature of the GP phase; and in the second stage of the electric pulse artificial aging, the GP phase separated out in the first stage of the electric pulse artificial aging is converted into a peak strengthening state beta' phase through electric pulse heat treatment.
Optionally, the temperature of the second stage of the electric pulse artificial aging is higher than the temperature of the first stage of the electric pulse artificial aging, and the temperature of the first stage of the electric pulse artificial aging is increased to the temperature required by the second stage of the electric pulse artificial aging according to a preset temperature rising curve.
Optionally, in the first stage of the artificial aging of the electric pulse, the nucleation temperature of the GP phase is 90-130 ℃; the current density of the applied electric pulse is 50-200 amperes/square millimeter, and the frequency of the electric pulse is more than or equal to 10 Hz; the temperature of the second stage of the artificial aging of the electric pulse is 220-260 ℃.
Optionally, the molding temperature path comprises a gradual cooling path, and the temperature self-insulation temperature of the gradual cooling path gradually decreases to a first preset temperature according to a preset first temperature decreasing curve; and/or the number of the groups of groups,
the molding temperature path comprises a constant temperature path, and the temperature of the constant temperature path keeps the heat preservation temperature for a preset time period.
Optionally, the step of varying the temperature of the part during its formation by means of an electrical pulse in accordance with a desired formation temperature path comprises:
acquiring a heat preservation temperature, a first preset temperature, an ambient temperature and a preset first temperature drop curve;
and adjusting the voltage value, the current value and the pulse duration of the electric pulse treatment according to the heat preservation temperature, the first preset temperature, the ambient temperature and the preset first temperature drop curve so as to supplement the temperature of the stamped part in real time.
Optionally, the step of adjusting the voltage value and the current value of the electric pulse processing according to the insulation temperature, the first preset temperature, the ambient temperature and the preset first temperature drop curve includes:
acquiring a target temperature at the current moment according to the heat preservation temperature, the first preset temperature, the ambient temperature and a preset first temperature drop curve;
acquiring the detection temperature of the current part;
And adjusting the voltage value, the current value and the pulse duration of the electric pulse treatment according to the difference value between the target temperature and the detected temperature.
Optionally, the step of varying the temperature of the part during its formation by means of an electrical pulse in accordance with a desired formation temperature path comprises:
acquiring a heat preservation temperature and an environment temperature;
and adjusting the voltage value, the current value and the pulse duration of the electric pulse treatment according to the heat preservation temperature and the ambient temperature so as to carry out real-time temperature supplementation on the stamped part.
Optionally, the temperature of the cooling temperature path is reduced to a second preset temperature according to a preset second temperature reduction curve, or the self-heat-preserving temperature is reduced to a third preset temperature according to a preset third temperature reduction curve; or alternatively, the process may be performed,
and reducing the temperature from the first preset temperature to a fourth preset temperature according to a preset fourth temperature reduction curve, or reducing the temperature from the first preset temperature to a fifth preset temperature according to a preset fifth temperature reduction curve.
Optionally, the second temperature drop curve and/or the fourth temperature drop curve are realized by pressure maintaining quenching on the part subjected to the electric pulse temperature compensation stamping forming; and/or the number of the groups of groups,
and the third temperature drop curve and/or the fifth temperature drop curve are realized by air cooling the part subjected to the electric pulse temperature compensation stamping forming.
Optionally, the step of obtaining a cooling temperature path required for the cooling process of the stamped part and controlling the cooling temperature variation of the part according to the forming temperature path and the cooling temperature path further comprises:
and naturally aging the cooled part.
The invention also provides a stamping device for realizing the stamping heat treatment process of the light alloy plate, which comprises the following steps:
heating the light alloy material to above the solid solution temperature and keeping the heat preservation temperature;
acquiring a forming temperature path required by the forming process of the stamping part, and enabling the temperature of the part to change according to the required forming temperature path in the forming process of the part through electric pulses so that the part has a preset stamping organization state;
acquiring a cooling temperature path required by the cooling process of the stamping part, and controlling the cooling temperature change of the part according to the forming temperature path and the cooling temperature path so as to enable the part to have a preset cooling structure state;
acquiring target strength and current strength of a part;
and determining that the current strength is smaller than the target strength, and performing an artificial aging process on the cooled part.
According to the technical scheme, the light alloy material is firstly heated to be above the solid solution temperature of the light alloy material and the heat preservation temperature is maintained; acquiring a forming temperature path required by the forming process of the stamping part, and changing the temperature of the part according to the required forming temperature path in the forming process by electric pulse so as to enable the part to have a preset stamping organization state; then, a cooling temperature path required by the cooling process of the stamping part is obtained, and the cooling temperature change of the part is controlled according to the forming temperature path and the cooling temperature path so that the part has a preset cooling structure state; therefore, the temperature of the part can be changed according to a forming temperature path required by stamping in the stamping process, so that the part can obtain a tissue state matched with the shape, structure and material of the part after stamping; in the cooling process, the temperature of the part can be changed according to a cooling temperature path required by cooling, so that the part is subjected to stamping to obtain a tissue state matched with the shape, structure and material of the part, the tissue state of the part in the stamping and cooling process is effectively optimized, and the physical properties of the formed part are greatly improved; acquiring the target strength and the current strength of the part; it is worth to say that in the heat-treatable reinforced aluminum alloy, the evolution process of the reinforced phase in the heat treatment is supersaturated solid solution- & gt Guinier-Preston (GP-focusing layer, enrichment region) region- & gt' & gt beta phase in the 2-series, 6-series, 7-series and other aluminum alloy series materials. Suitable heat treatment processes can provide greater dislocation shear stress to reach peak hardened conditions. Through the control of aging, the material can reach the peak hardening state quickly, so that the GP zone can be quickly separated out for nucleation and phase change to beta' phase with optimal size. The electric pulse can reduce the energy barrier required by nucleation in the aluminum matrix, and form nano-scale GP phase nuclei in a short time, so that the heat treatment time can be greatly reduced, and the production efficiency is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to the structures shown in these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic flow chart of an embodiment of a press forming process of a lightweight alloy sheet material according to the present invention;
FIG. 2 is a schematic view of an embodiment of a punch of the stamping die of the present invention;
FIG. 3 is a schematic view of the male die insert at the four corners of FIG. 2;
FIG. 4 is a schematic view of a die of the stamping device according to an embodiment of the present invention;
FIG. 5 is a schematic view of the die insert at the four corners of FIG. 4;
FIG. 6 is a schematic structural diagram of the working principle of the stamping die electric pulse heat compensation according to the invention;
FIG. 7 is a schematic flow chart of an embodiment of a stamping heat treatment process for a lightweight alloy sheet material;
FIG. 8 is a graph showing a temperature change path of an embodiment of a stamping heat treatment process for a lightweight alloy sheet material.
Reference numerals illustrate:
The achievement of the objects, functional features and advantages of the present invention will be further described with reference to the accompanying drawings, in conjunction with the embodiments.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It should be noted that all directional indicators (such as up, down, left, right, front, and rear … …) in the embodiments of the present invention are merely used to explain the relative positional relationship, movement, etc. between the components in a particular posture (as shown in the drawings), and if the particular posture is changed, the directional indicator is changed accordingly.
Furthermore, the description of "first," "second," etc. in this disclosure is for descriptive purposes only and is not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, "and/or" throughout this document includes three schemes, taking a and/or B as an example, including a technical scheme, a technical scheme B, and a technical scheme that both a and B satisfy; in addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent and not within the scope of protection claimed in the present invention.
The invention mainly provides a light alloy plate stamping forming process, which is mainly used for stamping forming a light alloy material, and by carrying out electric pulse treatment on the light alloy material while hot stamping, the electric pulse treatment is matched with the physical and material characteristics of the light alloy material, the shape, structure and size of a part to be stamped, so that the appointed area of the plate can reach the optimal temperature range required by stamping in extremely short time, thereby enabling the local recrystallization of the material, reducing the dislocation density, improving the plastic deformation capability, improving the formability, greatly reducing the requirements of a material transfer mechanism and a press, enabling the stamping of the part to be free from using an expensive rapid transfer mechanism and a press, and greatly reducing the stamping cost; meanwhile, the electric pulse inhibits the growth and coarsening of the strengthening phase in the material, so that the requirement on the temperature drop rate during pressure-maintaining quenching can be greatly reduced, the pressure-maintaining time is shortened, the energy consumption is reduced, and the production efficiency is improved; in addition, the electric pulse accelerates the nucleation of the strengthening phase, can quickly form the strengthening phase with uniform dispersion, provides a very good foundation for the subsequent aging heat treatment, can greatly reduce the heat treatment time and greatly improve the production efficiency of parts; in addition, proper electric pulse can promote nucleation and grain refinement of the plate, and a good tissue foundation is laid for further processing and improving the strength of the part. Among them, the form of the light alloy may be a plurality of forms, such as titanium alloy, magnesium alloy, aluminum alloy, etc., and the aluminum alloy is exemplified.
The specific steps of the light alloy sheet press forming process will be mainly described below.
Referring to fig. 1 to 8, in an embodiment of the present invention, the light alloy sheet press forming process includes the steps of:
s100, heating the light alloy material to the solid solution temperature or above;
s200, placing the heated light alloy material between the female die 200 and the male die 100;
s300, acquiring detection temperatures of all areas of the light alloy material;
and S400, closing the female die 200 and the male die 100 for stamping, and simultaneously, carrying out electric pulse treatment on the region according to the detection temperature.
Specifically, in the present embodiment, the light alloy may include an alloy material of aluminum alloy, magnesium alloy, titanium alloy, or the like. The shape of the light alloy material may be varied, and a plate-like arrangement is exemplified. There are many ways to heat the light alloy material to the solution temperature, such as heating in a furnace. After the light alloy material is heated to the solid solution temperature, the heat is preserved for a certain period of time until the alloy material is subjected to solid solution heat treatment. Specifically, the light alloy material is heated to the solid solution temperature or above, and is kept for a preset period of time until the strengthening phase in the structure of the light alloy material is completely fused into the solid solution, so that the formability of the plate reaches the optimal state. After the alloy material is heated to the desired state, the light alloy material is carried between the die 200 and the punch 100 in preparation for stamping. The transfer can be performed by a manipulator, and the heat conduction and the heat diffusion of the light alloy are very fast in the process of transferring the alloy material to the die, so that the transfer time is shortened as much as possible, and is usually controlled to be within 10 s.
Before the die 200 and the punch 100 are closed and punched, temperature detection is performed on each region of the alloy material. The light alloy material is divided into a plurality of regions, for example, the whole alloy material plate can be divided into a plurality of regions, that is, any part of the alloy material plate is divided into a certain region, and the temperature of the whole alloy material plate can be detected during temperature detection. Of course, in some embodiments, only a partial area of the alloy material, for example, an area with larger deformation, an area with a more complex structure, etc. may be detected, so as to improve the detection efficiency by reducing the detection amount, and of course, the detection method may be arranged according to the actual situation in the actual process.
In the stamping process, the female die 200 and the male die 100 are closed to perform stamping, and at the same time, the region is subjected to electric pulse treatment according to the detected temperature. Each region has a minimum guaranteed temperature or target temperature, and the minimum guaranteed temperature or target temperature can be different due to different positions or requirements. When the detected temperature is lower than the minimum guarantee temperature or the target temperature, the electric pulse is carried out on the area so as to carry out temperature compensation on the area, and the temperature is higher than the minimum guarantee temperature or the target temperature is reached. Therefore, the strengthening phase in the light alloy material structure is completely fused into the solid solution again, so that the formability of the plate is kept in an optimal state, the forming capability is improved, and the forming requirement is met.
In this embodiment, the light alloy material is heated to the solid solution temperature or above, and then the heated light alloy material is placed between the female die 200 and the male die 100; acquiring detection temperatures of all areas of the light alloy material before stamping, and then performing electric pulse treatment on the areas according to the detection temperatures while closing the female die 200 and the male die 100 for stamping; therefore, the heat energy of the required region can be timely and accurately supplemented, so that the strengthening phase in the alloy material tissue of the corresponding region is completely fused into the solid solution again, and the alloy material tissue is in the optimal molding state, so that the moldability is improved;
it is worth noting that when pulse current passes through the metal material, a large amount of free electrons (electron wind) with directional drift are generated, the drift electron group frequently impacts dislocation in a directional way, electron wind similar to external stress is generated on the dislocation section, and the dislocation is promoted to move on the sliding surface of the dislocation; thus, the electron wind effect generated by the current can provide nucleation energy of the strengthening phase, so that the strengthening phase can quickly nucleate, and a uniform nano-scale and dispersed precipitation strengthening phase is generated, and the heat treatment time is reduced; meanwhile, when pulse current is applied, electric energy, heat energy and stress are instantaneously input into the material, and random thermal motion of atoms obtains enough kinetic energy to leave an equilibrium position under the action of the instantaneous impact force of the pulse current, so that the diffusion capacity of the atoms is enhanced, dislocation is easier to slip and climb, and the plasticity of metal is improved;
Meanwhile, the electric pulse treatment is matched with the physical and material characteristics of the light alloy material, the shape and structure of a part to be punched and the size of the part, so that the appointed area of the plate can reach the optimal temperature range required by punching in extremely short time, thereby enabling the local part of the material to be dynamically recrystallized, reducing the dislocation density, improving the plastic deformation capability, improving the formability, greatly reducing the requirements of a material transfer mechanism and a press, enabling the punching of the part to be free from using an expensive rapid transfer mechanism and a press, and greatly reducing the punching cost; meanwhile, the electric pulse inhibits the growth and coarsening of the strengthening phase in the material, so that the requirement on the temperature drop rate during pressure-maintaining quenching can be greatly reduced, the pressure-maintaining time is shortened, the energy consumption is reduced, and the production efficiency is improved; in addition, the electric pulse accelerates the nucleation of the strengthening phase, can quickly form the strengthening phase with uniform dispersion, provides a very good foundation for the subsequent aging heat treatment, can greatly reduce the heat treatment time and greatly improve the production efficiency of parts. Meanwhile, the electric pulse mode realizes the temperature compensation or the maintenance of the plate material at the key part of the part through the structural design of the die for the plate material part needing heat supplement, so that the forming risk points are guaranteed to be overcome, and meanwhile, the electron wind effect of the electric pulse is utilized to promote the nucleation and grain refinement of the plate material, so that a good tissue foundation is laid for further processing and improving the strength of the part.
In some embodiments, in order to reduce the detection area, improve the detection efficiency and reduce the detection cost, the step of obtaining the detection temperature of each area of the light alloy material includes:
determining each risk area;
and detecting the temperature of each risk area to obtain the detection temperature.
Specifically, in this embodiment, the risk area is first determined, and the cause of the formation of the risk area may be various, such as the complexity of the structure, the deformation amount of the area, and so on. Thus, the determination of the risk area may be determined by theoretical derivation and calculation. Of course, under some operating conditions, it may also be determined by empirical analysis. Alternatively, in some embodiments, it may be determined by experimentation and detection, although the above three approaches may be used in combination. The following description will be given by taking an actual example.
The step of determining each risk area comprises the following steps:
obtaining target temperatures required by all areas when the light alloy plate is stamped and formed into the current part;
obtaining experimental temperature or simulation temperature of the light alloy plate during stamping;
determining that the target temperature is higher than the experimental temperature or the simulation temperature, and determining that the current region is a risk region; the experimental temperature is the temperature when the light alloy plate is not subjected to heat compensation in the stamping process; the simulation temperature is the temperature when the light alloy plate is not subjected to heat compensation in the simulation stamping process.
That is, before the actual mass production stamping, the stamping process of the part can be dynamically simulated in a three-dimensional simulation tool, so that the state of the stamped part can be seen under the condition that no electric pulse is loaded, and the damaged position or the position where the stamping does not meet the standard can be clearly obtained. These locations are then analyzed to find the reasons for unsuccessful stamping and the conditions required for stamping. Of course, the stamping experiment can be performed on the parts before the mass production stamping, so that the experiment temperature is obtained in the experiment, and then the target temperature required by the current area of the current part of the current material is obtained through the stamping experiment and the analysis of the material. It should be noted that the target temperature, the simulation temperature, and the experimental temperature may be obtained in different manners, or may be obtained in the same experiment or simulation. For example, the target temperature may be obtained by theoretical calculation, or may be obtained by experiment or simulation; the simulation temperature is usually obtained through simulation, and the experimental temperature is obtained through experiments. Under the condition that the target temperature is higher than the experimental temperature or the simulation temperature, the current area is determined to be a risk area, namely, the deformation state of the area can not meet the deformation requirement under the condition that the temperature compensation is not carried out on the area, and even phenomena such as breakage and the like are sent. After determining the risk area, the temperature of the detected risk area is taken as the detected temperature. The number of risk areas in the same part may be one or more. Each risk zone is equipped with temperature detection means and electrical pulse heating means.
In some embodiments, to further enhance the effect of the electrical pulse treatment, the step of subjecting the region to the electrical pulse treatment according to the detected temperature includes: comparing the current detection temperature with a target temperature required by a region when the current part is formed by stamping; and determining that the current detected temperature is lower than the target temperature, and performing electric pulse processing on the area. Wherein, confirm that the present detected temperature is lower than the goal temperature, carry on the step of the electric pulse treatment to the area including: acquiring the temperature difference between the detection temperature and the target temperature; and acquiring a voltage value and a current value of the electric pulse processing and the duration of the pulse processing according to the temperature difference.
Specifically, in the present embodiment, in the case where the material of the punched part and the structure, shape, and size of the part itself are determined, the target temperature required for each region at the time of punching may be one temperature value or one temperature range value. In the stamping process, the temperature of the area is detected in real time, and closed loop feedback is realized. As an example, when the temperature of the region is lower than the target temperature, the temperature of the region is compensated, and when the temperature of the region is higher than a certain value, the compensation is stopped, and the temperature of the region is maintained or reduced. Specifically, taking a target temperature as a target area temperature as an example, acquiring a detection temperature in real time, wherein the target temperature is the target area temperature; determining that the detected temperature exceeds the target area temperature; and according to the condition that the detected temperature exceeds the target area temperature, adjusting the voltage value and the current value of the electric pulse processing and the duration of the pulse processing so as to enable the current temperature to return to the target area temperature. When the detected temperature is higher than the maximum value of the temperature of the target area, the current temperature is too high, and the current value, the voltage value and the pulse processing duration are reduced, so that the temperature of the part is reduced to the temperature of the target area; when the detected temperature is lower than the minimum value of the target area temperature, the current temperature is too low, the current value and the voltage value are increased, and the pulse processing time length is increased, so that the temperature of the part is increased to the target area temperature. Thus, the part is ensured to be in a better molding state in the whole stamping process until the stamping action is finished.
In some embodiments, in order to further improve the physical characteristics of the part, the step of performing the electric pulse treatment on the area according to the detected temperature while the female die 200 and the male die 100 are closed for stamping further comprises: and (3) performing pressure maintaining quenching on the stamping formed part by using a cooling water channel arranged in the die. Specifically, in this embodiment, a cooling water channel is provided in the mold, and the arrangement of the cooling water channel corresponds to the structural feature arrangement of the part. After the part is subjected to pressure maintaining quenching, the structure state of the part is changed, so that the performance of the formed part is affected.
Of course, in some parts processing processes, it is also necessary to paint the parts, such as automobile parts. At this time, the formed parts are subjected to artificial aging heat treatment, so that the artificial aging heat treatment can be quickly realized in the whole vehicle paint spraying and baking process, and a separate heat treatment device is not needed.
The invention also provides a stamping device, which comprises a female die 200 and a male die 100, and is used for realizing a stamping forming process of the light alloy plate, and the specific scheme of the stamping forming process of the light alloy plate refers to the embodiment, and because the stamping device adopts all the technical schemes of all the embodiments, the stamping device at least has all the beneficial effects brought by the technical schemes of the embodiments, and the description is omitted herein.
It is worth noting that in some embodiments, for convenient temperature detection and temperature compensation of the area, inserts are provided on the mold at desired locations. Specifically, the stamping device includes a female die 200 and a male die 100, a male die insert 110 is disposed at a preset position of the male die 100, and a female die insert 210 is disposed at a position of the female die 200 corresponding to the male die 100; a thermocouple 370 is provided on either the die insert 210 or the punch insert 110. In the region, for example, a risk region, a die insert 210 and a punch insert 110 are provided on the die 200 and the punch 100 corresponding to the risk region of the part, respectively. The die insert 210 is detachably connected to the die 200, the punch insert 110 is detachably connected to the punch 100, and the surface of the die insert 210 conforms to the shape characteristics required for the surface of the die 200, and the surface of the punch insert 110 conforms to the shape characteristics required for the surface of the punch 100. The surface of the die insert 210 has a positive electrode 350 that is electrically connected to the electrical pulse power source 310 and the surface of the punch insert 110 has an accessory that is connected to the negative electrode 380 of the electrical pulse power source 310. A mounting hole is provided in the punch insert 110, and a temperature thermocouple 370 is mounted in the mounting hole. When the temperature is detected to be lower by the temperature measuring couple, the electric pulse circuit performs electric pulse temperature compensation on the detected area.
Referring to fig. 2 to 6, an aluminum alloy door inner panel for an electric vehicle will be described as an example. The part has complex shape and more characteristics, the traditional cold and hot methods can not successfully mold, the four corners of the part are the biggest difficult problems in molding, and the problems of cracking, wrinkling and the like are difficult to balance. The invention provides a method for realizing integral stamping forming of parts by adopting thermoforming and electric pulse complementary hot stamping. Determining the size of the cut plate according to the process scheme and the simulation analysis result; and heating and preserving the heat of the cut plate, wherein the heating temperature is higher than the solid solution temperature, the preserving time is selected according to the optimal solid solution time of the plate, and the preserving time is generally 3-30min, so that the strengthening phase in the plate tissue is ensured to be completely fused into the solid solution, and the formability of the plate reaches the optimal state. Then the plate is transferred into a mould by a manipulator, and the transfer time is as short as possible and is generally controlled within 10s because the heat conduction and the heat diffusion of the light alloy are very fast; stamping the plate transferred to the die to form the required product shape in the closing process of the upper die and the lower die, and simultaneously, screening out a formed risk area from simulation analysis; a temperature detecting device and an electric pulse heat supplementing device are specifically designed at the position of the die, the temperature of the area is fed back in real time in the stamping process, the electric pulse heat supplementing is started when the temperature is lower than the ideal forming temperature (generally 400-450 ℃), and the stability of the temperature of the plate is controlled through closed-circuit feedback until the stamping action is finished; after stamping, the cooling water channel arranged in the die is utilized to carry out die pressure maintaining quenching on the parts, so that the structure state of the parts is changed, and the performance of the finished part forming is affected.
Wherein, four corners of the part are four risk areas, four male die inserts 110 are arranged on the male die 100 corresponding to the four risk areas, and four female die inserts 210 are arranged on the female die 200 corresponding to the four risk areas. The electric pulse of each risk area can be independently controlled, and different currents, voltages and pulse processing durations are provided according to different specific requirements, so that different pulse processing can be provided for different working conditions at the same time.
The installation place of the temperature thermocouple 370 and the electric pulse connection electrode is determined according to the initial contact position of the plate material, and generally, the installation position is in the area where the die firstly contacts the plate material (the die 100 can be arranged on the male die 200 or the female die 200, and the die 100 is generally designed as far as possible, so that the die is easy to install and fix). The early contact places are cooled most quickly in the stamping process, and the flatter parts with convex characteristics are selected to be drilled and provided with temperature detection thermocouples. The positive and negative electrodes 380 are designed to fully utilize the features of the parts and the mold, and a more gentle feature surface on the mold is selected along the boundary of the electric pulse heat compensation area. The width is 20-30mm, can split into two halves, each half is split into small inserts, the small inserts are processed into characteristic shapes of parts, the small inserts are used as electrodes, then the electrodes are connected with a die main body through screws, the electrodes are isolated from the die main body through insulating materials, and after the design and installation are finished, the accurate heat compensation and temperature control of a local area are ensured. After the thermocouple detects the temperature, the feedback controller 320 is used for controlling whether the electric pulse circuit continues to work and adjusting pulse parameters, if the local temperature is lower than the set temperature, the electric pulse circuit continues to be electrified and heated, after the temperature reaches the set temperature, the current, the frequency and the pulse time are reduced to maintain the temperature, and when the temperature is higher than the pulse temperature, the electric pulse circuit is automatically powered off, so that an automatic control closed loop system is formed. The sheet material is ensured to be in an ideal thermal state in the die at any time, and the optimal condition is provided for forming.
According to the electric pulse heating mentioned in the above embodiment, in order to perform appropriate electric pulse treatment for a desired position more precisely, a light alloy sheet stamping heat treatment process is proposed below, comprising the steps of:
s10, heating the light alloy material to a temperature above the solid solution temperature of the light alloy material and keeping the heat preservation temperature;
s20, acquiring a forming temperature path required by a forming process of the stamping part, and enabling the temperature of the part to change according to the required forming temperature path in the forming process of the part through electric pulses so that the part has a preset stamping structure state;
s30, acquiring a cooling temperature path required by the cooling process of the stamping part, and controlling the cooling temperature change of the part according to the forming temperature path and the cooling temperature path so as to enable the part to have a preset cooling structure state.
Specifically, in this embodiment, the light alloy material is heated above its solution temperature and held at a soak temperature until the alloy material is finished with the solution heat treatment. Specifically, the light alloy material is heated to the solid solution temperature or above, and is kept for a preset period of time until the strengthening phase in the structure of the light alloy material is completely fused into the solid solution, so that the formability of the plate reaches the optimal state.
There are many ways to obtain the required forming temperature paths for the stamping part forming process, and the required forming temperature paths may be different for different materials, different part structures, shapes and sizes. In the following, the material, structure, shape and dimensions of the part are determined in a few ways to obtain the forming temperature path. By means of theoretical calculation, the stamping forming temperature path can be obtained, and main reference factors of the stamping forming temperature path comprise materials, structures, shapes and sizes of parts, and working environments and working scenes of the parts at later times. The test piece can also be obtained by a stamping test mode, and can also be obtained by a simulation mode. In some embodiments, in order to improve the working efficiency, a very accurate and reliable forming temperature path is obtained by theoretical calculation, simulation test and stamping experiment. After the forming temperature path is determined, a temperature-time change curve in the stamping process is determined, so that the temperature at each moment in the stamping process has a corresponding value, and in some embodiments, the temperature value at each moment can be within a certain temperature range. In this way, the electric pulse adjusts the temperature of the region according to the temperature value or the temperature range at each moment, thereby ensuring that the region is kept in an optimal forming state at each moment in the stamping process, and ensuring that the stamped and formed part has a preset stamping organization state. When the part has a preset stamping structure state, the stamping forming process is perfect, and a good foundation is provided for the subsequent process.
Similarly, the parts need to be cooled after stamping, and the ways to obtain the cooling temperature paths needed in the cooling process of the stamped parts are numerous, and the cooling temperature paths needed may be different for different materials, different part structures, shapes and sizes. In the following, the cooling temperature path is obtained in a number of ways, with the material, structure, shape and dimensions of the part being determined. By means of theoretical calculation, the stamping cooling temperature path can be obtained, and main reference factors of the stamping cooling temperature path include materials, structures, shapes and sizes of parts, and working environments and working scenes of the parts at later times. The test piece can also be obtained by a stamping test mode, and can also be obtained by a simulation mode. In some embodiments, in order to improve the working efficiency, a very accurate and reliable cooling temperature path is obtained by theoretical calculation, simulation test and stamping experiment. After determining the cooling temperature path, the temperature-time profile during the stamping process is determined so that the temperature at each time during the cooling process has a corresponding value, although in some embodiments, the temperature value at each time may be within a certain temperature range. In this way, the electric pulse adjusts the temperature of the region according to the temperature value or the temperature range at each moment, thereby ensuring that the region is kept in an optimal state at each moment in the stamping process, and ensuring that the formed part is cooled and has a preset cooling organization state. When the part has a preset cooling structure state, the cooling process is perfect, and a good foundation is provided for the subsequent process.
In the embodiment, firstly, the light alloy material is heated to be above the solid solution temperature and the heat preservation temperature is maintained; acquiring a forming temperature path required by the forming process of the stamping part, and changing the temperature of the part according to the required forming temperature path in the forming process by electric pulse so as to enable the part to have a preset stamping organization state; then, a cooling temperature path required by the cooling process of the stamping part is obtained, and the cooling temperature change of the part is controlled according to the forming temperature path and the cooling temperature path so that the part has a preset cooling structure state; therefore, the temperature of the part can be changed according to a forming temperature path required by stamping in the stamping process, so that the part can obtain a tissue state matched with the shape, structure and material of the part after stamping; in the same way, the temperature of the part can be changed according to a cooling temperature path required by cooling in the cooling process, so that the part is subjected to stamping to obtain a tissue state matched with the shape, structure and material of the part, the tissue state of the part in the stamping and cooling process is effectively optimized, and the physical characteristics of the formed part are greatly improved.
The forming temperature path may take many forms, and in some embodiments, different forming temperature paths are required for different part characteristics (materials, shapes, structures, dimensions, operating environments, etc.), to further purposefully enhance the structural state and physical properties of the part, as described below by way of example.
The forming temperature path comprises a gradual cooling path, and the temperature self-insulation temperature of the gradual cooling path gradually decreases to a first preset temperature according to a preset first temperature decreasing curve; and/or the forming temperature path comprises a constant temperature path, and the temperature of the constant temperature path keeps the heat preservation temperature for a preset time period.
Specifically, in this embodiment, when the molding temperature path includes a gradual cooling path, the temperature self-insulation temperature of the gradual cooling path gradually decreases to a first preset temperature according to a preset first temperature decreasing curve. That is, under the condition of the gradual cooling path, the temperature of the part gradually decreases according to the first temperature decreasing curve, the starting point of the temperature decreasing curve is the heat preservation temperature, and the end point is the first preset temperature. It should be noted that, the temperature value on the first temperature drop curve may be a fixed value or a temperature range value; the first preset temperature may be a specific temperature value or a temperature range value. When the temperature value on the first temperature drop curve and the first preset temperature are the temperature range values, the electric pulse processing only needs to ensure the temperature of each moment of the forming temperature path, and the temperature is within the temperature range values.
Specifically, the step of varying the temperature of the part during its formation by means of an electrical pulse in accordance with a desired formation temperature path comprises: acquiring a heat preservation temperature, a first preset temperature, an ambient temperature and a preset first temperature drop curve; and adjusting the voltage value, the current value and the pulse duration of the electric pulse treatment according to the heat preservation temperature, the first preset temperature, the ambient temperature and the preset first temperature drop curve so as to supplement the temperature of the stamped part in real time. In this embodiment, the heat preservation temperature, the first preset temperature, and a temperature drop curve are all related to the characteristics of the part, and these parameters may be obtained by real-time calculation or may be retrieved from a preset database, where, of course, a mapping table of the part and the heat preservation temperature, the first preset temperature, and a temperature drop curve is stored in the database. The ambient temperature may be obtained by direct detection by a temperature detection device, or may be obtained from another device or a network by communication. After the heat preservation temperature, the first preset temperature, the ambient temperature and the preset first temperature drop curve are determined, the electric pulse can accurately control the temperature by adjusting the voltage value, the current value and the pulse duration, so that the part has a very good tissue state in the stamping process.
Of course, in some embodiments, in order to perform the point pulse processing on the area more accurately, the step of adjusting the voltage value and the current value of the electric pulse processing according to the holding temperature, the first preset temperature, the ambient temperature and the preset first temperature drop curve includes: acquiring a target temperature at the current moment according to the heat preservation temperature, the first preset temperature, the ambient temperature and a preset first temperature drop curve; acquiring the detection temperature of the current part; and adjusting the voltage value, the current value and the pulse duration of the electric pulse treatment according to the difference value between the target temperature and the detected temperature. The higher the target temperature is higher than the detection temperature, the higher the voltage value and the current value of the electric pulse treatment are, and the longer the pulse duration is; the lower the target temperature is above the detected temperature, the lower the voltage value and the current value of the electric pulse treatment, and the shorter the pulse duration. When the target temperature is lower than the detected temperature, the voltage value and the current value are further reduced, and the pulse duration is shortened, in some embodiments, the operation of the electric pulse may be stopped according to the actual situation.
The forming temperature path comprises a constant temperature path, the temperature of the constant temperature path keeps the heat preservation temperature for a preset time, and the step of changing the temperature of the part according to the required forming temperature path in the forming process by electric pulse comprises the following steps: acquiring a heat preservation temperature and an environment temperature; and adjusting the voltage value, the current value and the pulse duration of the electric pulse treatment according to the heat preservation temperature and the ambient temperature so as to carry out real-time temperature supplementation on the stamped part.
There may be many forms of cooling temperature paths, and in some embodiments, different cooling temperature paths are required for different part characteristics (materials, shapes, structures, dimensions, working environments, etc.), as will be described below, to further specifically enhance the structural state and physical properties of the part.
The temperature of the cooling temperature path is reduced to a second preset temperature according to a preset second temperature reduction curve, or the self-heat-preservation temperature is reduced to a third preset temperature according to a preset third temperature reduction curve; or the temperature of the cooling temperature path is reduced from the first preset temperature to the fourth preset temperature according to a preset fourth temperature reduction curve, or is reduced from the first preset temperature to a fifth preset temperature according to a preset fifth temperature reduction curve.
The initial temperature at the time of entering the cooling stage is different due to the different molding temperature paths at the molding stage. When the forming temperature path changes according to the constant temperature path, the initial temperature after entering the cooling stage is the heat preservation temperature, the forming temperature path is carried out according to the temperature of the gradual cooling path, and the initial temperature after entering the cooling stage is the first preset temperature. Based on this, the form of the cooling temperature path can be more diversified. The temperature reduction conditions of the initial temperature being the heat preservation temperature and the first preset temperature are respectively described below.
The self-heat-preservation temperature is reduced to a second preset temperature according to a preset second temperature reduction curve, or the self-heat-preservation temperature is reduced to a third preset temperature according to a preset third temperature reduction curve; the second preset temperature and the third preset temperature may be the same or different. The second temperature drop curve and the third temperature drop curve may be straight lines or curves. In this embodiment, the second temperature drop curve and the third temperature drop curve have different temperature drop paths, regardless of whether the second temperature drop curve and the third temperature drop curve are identical. For example, the slope of the second temperature drop curve is greater than the slope of the third temperature drop curve, i.e., the temperature drop rate of the second temperature drop curve is greater than the temperature drop rate of the third temperature drop curve.
Similarly, the temperature is reduced from the first preset temperature to the fourth preset temperature according to a preset fourth temperature reduction curve, or the temperature is reduced from the first preset temperature to a fifth preset temperature according to a preset fifth temperature reduction curve. The fourth preset temperature and the fifth preset temperature may be the same or different. The fourth temperature drop curve and the fifth temperature drop curve may be straight lines or curves. In this embodiment, the temperature drop paths of the fourth temperature drop curve and the fifth temperature drop curve are different, regardless of whether the fourth temperature drop curve and the fifth temperature drop curve are identical. For example, the slope of the fourth temperature drop curve is greater than the slope of the fifth temperature drop curve, i.e., the temperature drop rate of the fourth temperature drop curve is greater than the temperature drop rate of the fifth temperature drop curve.
In the actual cooling process, there are many ways to implement the second cooling curve, the third cooling curve, the fourth cooling curve, and the fifth cooling curve, which are illustrated below.
The second temperature drop curve and/or the fourth temperature drop curve are realized by carrying out pressure maintaining quenching on the part subjected to the electric pulse temperature compensation stamping forming; and/or the third temperature drop curve and/or the fifth temperature drop curve is realized by air cooling the part subjected to the electric pulse temperature compensation stamping forming. That is, the second temperature drop curve and the fourth temperature drop curve may be realized by performing pressure-maintaining quenching on the part, and the third temperature drop curve and the fifth temperature drop curve may be realized by performing air cooling on the part.
In some embodiments, to further improve the physical characteristics of the cooled part, the step of obtaining a cooling temperature path required for the cooling process of the stamped part and controlling the cooling temperature variation of the part according to the forming temperature path and the cooling temperature path further comprises: and naturally aging the cooled part.
In some embodiments, to further increase the strength of the part, the step of obtaining a cooling temperature path required for the cooling process of the stamped part and controlling the cooling temperature variation of the part according to the forming temperature path and the cooling temperature path further comprises, after: acquiring target strength and current strength of a part; and determining that the current strength is smaller than the target strength, and artificially aging the cooled part. When the strength of the part is determined to be insufficient, the strength of the part can be increased through artificial aging after the part is cooled so as to meet the requirement of the part.
In the heat-treatable reinforced aluminum alloy of series 2, 6, 7, etc., the evolution process of the reinforced phase in the heat treatment is supersaturated solid solution→guilier-Preston (GP-focusing layer, enrichment zone) zone→β "→β' →β phase. The optimal heat treatment process should be such that the β "phase ratio in the material is relatively large and large in size, providing a large dislocation shear stress to reach the peak hardened state. In order for the material to reach the peak hardening state quickly, it is desirable that the GP zone be able to precipitate quickly to nucleate and phase change to the optimally sized β "phase. The electric pulse can reduce energy barrier required by nucleation in the aluminum matrix, and nano-scale GP phase nuclei are formed in a short time. The method can greatly reduce the heat treatment time and improve the production efficiency.
Referring to FIG. 8, an example of the temperature change of the electric pulse heat compensation process when an automobile door is processed by using a specific aluminum alloy sheet is shown below.
Compared with the traditional heating method or heating, stamping and cooling technology, the plate with electric pulse heat supplementing function in the hot stamping process has finer crystal grains and more nucleation, and the difference in structure directly leads to the shortening of the heating time and the reduction of the temperature of the subsequent aging treatment, so that the efficiency is greatly improved under the condition of meeting the strength requirement of parts. According to the different brands of the aluminum alloy of the plate and the different required strength of the part, the subsequent heat treatment process can select the aging strengthening treatment and baking varnish strengthening treatment for heat preservation for a certain time at a certain specific temperature, and even can directly perform baking varnish strengthening on the formed part so as to meet the strength requirement of the part. The specific heat treatment process route and the description are as follows:
T SHT : heating and solutionizing temperature of the aluminum alloy;
t 0 —t 1 : heating;
t 1 —t 2 : a heat preservation process;
t 2 —t 3 : the forming process, (1) the path represents pulse temperature compensation, only the slow temperature drop in the forming process is realized, and (2) the path represents pulse heating to maintain the temperature unchanged in the plate deformation process;
t 3 —t 4 : a cooling path (3) for carrying out pressure maintaining quenching on the die after the electric pulse temperature compensation forming;
t 3 —t 5 : a cooling path (4) for cooling the air after the electric pulse temperature compensation molding;
t 3 —t 6 : a cooling path (5) for carrying out pressure maintaining quenching on the die after electric pulse constant temperature forming;
t 3 —t 7 : a cooling path (6) for cooling the electric pulse after the electric pulse is molded at a constant temperature;
t 7 —t 8 : naturally aging, wherein the time period can be long or short according to the process requirement;
t 8 —t 9 : in the first stage of the artificial aging of the electric pulse, a path (7) represents the process of heating and preserving heat by artificial aging, and whether the artificial aging process of the electric pulse is needed or not depends on the strength requirement of the part; heat of electric pulse to promote GP phase nucleationThe treatment process should be applied after forming (t 8-t 11), the workpiece should be placed in an aging heating device, and the temperature should be lower than the solvus temperature of the GP phase, for example, for 6-series aluminum alloys, the optimal temperature for GP phase nucleation is 90-130 degrees celsius, for example, 110 degrees celsius. The current density of the applied electric pulse ranges from 50 ampere/square millimeter to 200 ampere/square millimeter, the frequency of the electric pulse is not lower than 10 Hz, and the temperature of the workpiece during the application of the electric pulse does not exceed the temperature of the GP phase solvus at 110 ℃. The treatment time at this stage is 0 min (millisecond level) to 3 min;
t9-t10: and an electric pulse artificial aging second stage, wherein the heat treatment is performed to convert the GP phase precipitated in the electric pulse artificial aging first stage into a peak strengthening state beta', for example, the effective temperature range is 220-26 ℃ for 6-series aluminum alloy, and 240 ℃ is taken as an example. The treatment time at this stage is 0 (millisecond level) to 5 minutes. The current density of the applied electric pulse ranges from 50 ampere/square millimeter to 200 ampere/square millimeter, the frequency of the electric pulse is not lower than 10 Hz, and the temperature of the workpiece during the application of the electric pulse is not higher than the effective precipitation temperature of the strengthening phase by 240 ℃. the optimal process parameters for t8-t11 are determined by orthogonal tests and based on the strength and ductility requirements of the product.
It is worth noting that the temperature of the second stage of the electric pulse artificial aging is higher than that of the first stage of the electric pulse artificial aging, and the temperature of the first stage of the electric pulse artificial aging is increased to the temperature required by the second stage of the electric pulse artificial aging according to a preset temperature rising curve. The preset heating curve can be an inclined straight line or a curve, and can be correspondingly adjusted according to actual conditions. Similarly, in the first stage (t 8 —t 9 ) And an electrical pulse artificial aging second stage (t 9 —t 10 ) In the method, the respective constant temperature can be kept, the temperature can be changed gradually, the temperature can be changed linearly or changed in a curve, and particularly, the method can be properly adjusted according to factors such as actual working condition requirements, such as materials, current environment temperature and the like.
t 11 —t 12 : baking the paint, wherein the stage is determined according to the requirement, and the automobile panel is commonly used;
the plate organization after the electric pulse complementary hot stamping provides more flexible and diversified heat treatment process paths for the treatment of subsequent parts, and different paths can be selected or even some processes can be omitted according to the final strength acceptance criteria and organization requirements of the parts.
The invention also provides a stamping device, which comprises a female die 200 and a male die 100, and is used for realizing a stamping forming process of the light alloy plate, and the specific scheme of the stamping heat treatment process of the light alloy plate refers to the embodiment, and because the stamping device adopts all the technical schemes of all the embodiments, the stamping device at least has all the beneficial effects brought by the technical schemes of the embodiments, and the description is omitted.
The foregoing description is only of the preferred embodiments of the present invention and is not intended to limit the scope of the invention, and all equivalent structural changes made by the description of the present invention and the accompanying drawings or direct/indirect application in other related technical fields are included in the scope of the invention.
Claims (7)
1. The stamping heat treatment process for the light alloy plate is characterized by comprising the following steps of:
heating the light alloy material to above the solid solution temperature and keeping the heat preservation temperature;
acquiring a forming temperature path required by the forming process of the stamping part and acquiring detection temperatures of all areas of the stamping part, and performing electric pulse treatment on the corresponding areas according to the detection temperatures so as to enable the temperature of the part to change according to the required forming temperature path in the forming process of the part through electric pulses, so that the part has a preset stamping organization state; the forming temperature path comprises a gradual cooling path, and the self-insulation temperature of the gradual cooling path gradually decreases to a first preset temperature according to a preset first temperature decreasing curve; and/or the forming temperature path comprises a constant temperature path, and the temperature of the constant temperature path keeps the heat preservation temperature for a preset time period;
the step of varying the temperature of the part during its formation by means of the electrical pulse according to a desired formation temperature path comprises:
acquiring a heat preservation temperature, a first preset temperature, an ambient temperature and a preset first temperature drop curve;
adjusting the voltage value, the current value and the pulse duration of the electric pulse treatment according to the heat preservation temperature, the first preset temperature, the ambient temperature and the preset first temperature drop curve so as to carry out real-time temperature supplementation on the stamped part; and/or the number of the groups of groups,
The step of varying the temperature of the part during its formation by means of the electrical pulse according to a desired formation temperature path comprises:
acquiring a heat preservation temperature and an environment temperature;
adjusting the voltage value, the current value and the pulse duration of the electric pulse treatment according to the heat preservation temperature and the environment temperature so as to carry out real-time temperature supplementation on the stamped parts;
the step of obtaining the detection temperature of each area of the stamping part comprises the following steps:
determining each risk area;
detecting the temperature of each risk area to obtain a detection temperature;
the electric pulse processing of the corresponding area according to the detected temperature comprises the following steps:
comparing the detected temperature with the minimum guaranteed temperature or target temperature of the area;
if the detected temperature is lower than the minimum guarantee temperature or the target temperature, carrying out electric pulse treatment on the area;
acquiring a cooling temperature path required by the cooling process of the stamping part, and controlling the cooling temperature change of the part according to the forming temperature path and the cooling temperature path so as to enable the part to have a preset cooling structure state;
acquiring target strength and current strength of a part;
and determining that the current strength is smaller than the target strength, and performing an artificial aging process on the cooled part.
2. The stamping heat treatment process of the light alloy plate according to claim 1, wherein the artificial aging comprises an electric pulse artificial aging first stage and an electric pulse artificial aging second stage, wherein the heat treatment process of promoting the nucleation of the GP phase by the electric pulse in the electric pulse artificial aging first stage is applied after forming, and a workpiece is placed in an aging heating device, and the temperature is lower than the melting temperature of the GP phase; and in the second stage of the electric pulse artificial aging, the GP phase separated out in the first stage of the electric pulse artificial aging is converted into a peak strengthening state beta' phase through electric pulse heat treatment.
3. The stamping heat treatment process of the light alloy sheet according to claim 2, wherein the temperature of the second stage of the electric pulse artificial aging is higher than the temperature of the first stage of the electric pulse artificial aging, and the temperature of the first stage of the electric pulse artificial aging is increased to the temperature required by the second stage of the electric pulse artificial aging according to a preset heating curve.
4. The light alloy sheet stamping heat treatment process according to claim 3, wherein in the first stage of the electric pulse artificial aging, the temperature of GP phase nucleation is 90-130 ℃; the current density of the applied electric pulse is 50-200 amperes/square millimeter, and the frequency of the electric pulse is more than or equal to 10 Hz; the temperature of the second stage of the artificial aging of the electric pulse is 220-260 ℃.
5. The process according to any one of claims 1 to 2, wherein the temperature of the cooling temperature path is reduced from the self-heat-preserving temperature to a second preset temperature according to a preset second heat-preserving temperature reduction curve, or is reduced from the self-heat-preserving temperature to a third preset temperature according to a preset third heat-preserving temperature reduction curve; or alternatively, the process may be performed,
and reducing the temperature from the first preset temperature to a fourth preset temperature according to a preset fourth temperature reduction curve, or reducing the temperature from the first preset temperature to a fifth preset temperature according to a preset fifth temperature reduction curve.
6. The light alloy sheet stamping heat treatment process according to claim 5, wherein the second temperature drop curve and/or the fourth temperature drop curve is realized by pressure-maintaining quenching of the part after the electric pulse temperature compensation stamping forming; and/or the number of the groups of groups,
and the third temperature drop curve and/or the fifth temperature drop curve are realized by air cooling the part subjected to the electric pulse temperature compensation stamping forming.
7. The process according to claim 1, wherein the step of obtaining a cooling temperature path required for the cooling process of the punched part and controlling the cooling temperature variation of the part according to the forming temperature path and the cooling temperature path further comprises, after the step of:
And naturally aging the cooled part.
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