JP2004130350A - Method for forming aluminum alloy automobile panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a forming method of an aluminum alloy automobile panel by which the forming of a shape part where becomes stretch flanging or shrinkage flanging when the aluminum alloy automobile panel is formed with a press is enabled. <P>SOLUTION: This method is a method for forming the aluminum alloy automobile panel 1 by press forming and, by performing the forming of the shape part 3a, 3b where stretch flanging or shrinkage flangingis perfomed when the panel is formed by pressing is performed by the electromagnetic forming, the forming of the part of the stretch flanging or the shrinkage flanging is enabled. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for forming an aluminum alloy automobile panel (hereinafter, aluminum is also referred to as Al).
[0002]
[Prior art]
Conventionally, panels such as outer panels (outer panels) and inner panels (inner panels) of panel structures such as automobile hoods, fenders, doors, roofs, and trunk lids have been made of thin and high-strength Al alloy panels. Al-Mg-based 5,000-based aluminum alloy sheets (rolled sheet materials) having excellent formability and Al-Mg-Si-based 6000-based aluminum alloy sheets (rolled sheet materials) having excellent formability and bake hardenability have begun to be used.
[0003]
As is well known, a panel such as an outer panel or an inner panel of an automobile is formed into a final panel shape by pressing an aluminum alloy plate. As is well known, an outer panel of an automobile or the like is manufactured by combining the same aluminum alloy plate with a forming process such as a bulging process in a press forming process or a bending process. For example, an outer panel such as a hood or a door is formed into a molded product as an outer panel by press forming such as overhang, and then is bonded to the inner panel by hemming a flat hem or the like around the outer panel periphery. Is performed to form a panel structure.
[0004]
In recent years, in view of the design and design of the body of an automobile or the like, the size of the panel molded product has become larger and more complicated, and a panel molded product having a large number of curved surface portions has been required as a design shape.
[0005]
For example, FIG. 1A is a perspective view showing an example of a panel molded product having a largely curved side wall portion and a flange portion, such as an automobile outer panel. In FIG. 1 (a), a panel molded product 1 has a product portion 2 having a relatively large height h and a flange portion (excess portion) having a width w which becomes a part of the panel molded product or is selectively cut off later. Consists of four. Characteristically, the product side wall portion 3 has curved portions such as curved side wall portions 3a and 3b and curved flange portions 4a and 4b which are curved in a large arc shape.
[0006]
The aluminum alloy plate is inferior in formability to a portion that is difficult to form, such as a curved portion, as compared with a steel plate. For this reason, when manufacturing a panel molded product having such a curved portion by press molding such as overhanging from an aluminum alloy plate, a crack X 2 is likely to be generated in the curved portion. This tendency of the curved portion to crack becomes particularly strong when the curvature of the curved portion is increased. This is because the aluminum alloy material of the curved portion is partially stretched and flange deformation occurs.
[0007]
That is, the deformation from the flange bending portions 4a, 4b to the product bending portions 3a, 3b is different from the two-dimensional deformation of other parts, and is a three-dimensional deformation of a fan-shaped portion (shown by oblique lines). It becomes a deformation. In the case of this stretched flange deformation, as the flange curved portions 4a and 4b move toward the product curved portions 3a and 3b in the direction of arrow a, the end 4c of the flange curved portion moves in the direction of arrow b that is perpendicular to arrow a. And it will grow. The larger the degree of curvature or the scale of the side wall portion or the flange portion of the panel molded product, the greater the amount of movement of the flange curved end portion 4c, and therefore the greater the stretch flange deformation. As a result, the amount of strain applied to the material in this portion increases, and cracks X, which are breakage of stretch flanges, are likely to occur. For this reason, when the shape of the aluminum alloy panel molded product becomes larger and more complicated, and the degree of curvature and scale of the side wall portion and the flange portion are increased, the tendency of occurrence of flange end portion cracking is particularly increased. .
[0008]
There is a limit to preventing such cracks by improving the stretch flangeability on the aluminum alloy material side. Further, in order to prevent this cracking, there is a limit to improvement on general molding conditions such as using a draw bead 9 or increasing a wrinkle pressing force by a blank holder to suppress the material from flowing into a mold. is there.
[0009]
Therefore, at present, especially in the case of a panel material made of an aluminum alloy, there is a great limitation on the degree of curvature and scale of the curved portion of the panel molded product that can be molded. For this reason, in reality, the only choice was to use a material with good formability at the expense of strength (low strength) or to change the design of the panel members.
[0010]
In addition, in press forming of an aluminum alloy automobile panel, a large number of other formed portions that cause such stretch flange deformation and contraction flange deformation are generated. For example, after a press-formed panel is provided with a through hole, as shown in the sectional views of FIGS. 3 (a) and 3 (b), the through hole 22 is further expanded by a hole expanding process to form an aluminum alloy panel 21. In some cases, a flange (overhang portion, boss portion) 23 having a certain height h is formed. If there is a through hole 22 including the flange 23, it is easy to attach another component such as a bolt or a fastening jig via a washer or the like. Further, the flange 23 having a certain height h 1 serves as a guide for preventing displacement of these shafts when attaching a fastening jig such as a bolt. Also, due to the increase in the joining area and joining length by the flange 23, even if the aluminum alloy panel 21 is a thin plate, the length necessary for fixing the shaft (member) such as the bolt is secured, and other parts and fastenings are made. Fixing of the jig and bonding strength can also be secured. These effects increase as the height h 2 of the flange 23 increases. Further, in addition to the above advantages, the rigidity of the aluminum alloy panel 21 is increased by providing a predetermined number of the flanges 23 irrespective of attachment of other parts or fastening jigs, as compared with a flat aluminum alloy panel. It is possible.
[0011]
In order to form the flange 23 having such a constant height in the through hole 22 of the aluminum alloy panel, first, the through hole 22 is provided by a punching process shown in FIG. 22 is expanded. However, this hole enlarging process is a press process accompanied by the stretch flange deformation, and in such a press process, the amount of strain applied to the material of the deformed portion increases due to the stretch flange deformation. For this reason, cracks that penetrate the plate thickness from the edge (end face) of the flange 23 tend to occur. This crack is more likely to occur as the height h 2 of the flange 23 increases. Also, the higher the strength of the aluminum alloy panel and the thinner the plate thickness is 5 mm or less, the more remarkable. When this crack occurs, a fatal problem arises in that the processed aluminum alloy plate panel cannot be used for a structure or the like.
[0012]
On the other hand, application of electromagnetic molding technology has been proposed as a new molding technology for panels and the like. Electromagnetic forming itself instantaneously applies (discharges) electric energy (charge) stored at a high voltage to a current-carrying coil, and forms an extremely short-time strong magnetic field. Utilizing the fact that the placed work (workpiece, metal member) is subjected to strong expansion and contraction by the repulsive force of the magnetic field (Lorentz force according to Fleming's left hand rule) and plastically deforms at high speed. This is a technique for plastically processing or forming a work into a predetermined shape.
[0013]
This electromagnetic molding is intended for molding metal members such as metal plates and tubes, which are highly conductive and easily generate eddy current, and are used for forming plates, expanding tubes, contracting tubes, and tube ends. Promising for molding. In particular, an aluminum alloy is a good conductor of electricity and is a material suitable for this electromagnetic forming.
[0014]
As a specific example of the application of forming an aluminum alloy plate, use for forming an aluminum alloy can body (plate) has been proposed (for example, see Patent Document 1). Further, use for forming ribs (projections) on an aluminum alloy core plate (plate) has been proposed (for example, see Patent Document 2). Further, as a more specific electromagnetic forming method of a plate, a coil having a shape corresponding to the plate portion to be formed is provided close to the surface side of the plate, while the mold forming surface is close to the opposite surface side of the plate. An aluminum alloy plate formed by applying electric energy to the coil to deform the plate portion to be formed and pressing only one side of the deformed plate surface against the mold forming surface to form a predetermined curved surface shape Has been proposed (see Non-Patent Document 1).
[0015]
[Patent Document 1]
JP-A-9-29370 (pages 1-2, FIG. 1)
[Patent Document 2]
JP-A-1998-156461 (pages 1 and 2, FIG. 1)
[Non-patent document 1]
Toshio Sano and four others, "Study on Plastic Working Using Electromagnetic Force", "Mechanical Engineering Laboratory Report No. 150", published in March 1990, Mechanical Engineering Laboratory (Chapter 3
Forming of board, pp. 7-28)
[0016]
If this electromagnetic forming method can be applied to a formed portion that undergoes stretch flange deformation or shrink flange deformation, such as overhang forming of the curved portion of the aluminum alloy panel, it is possible to solve various problems of forming defects such as cracks and shape defects. .
[0017]
[Problems to be solved by the invention]
However, electromagnetic forming of automotive aluminum alloy panels has not yet been put to practical use. This is due to the fact that it is more difficult to form aluminum alloy plates by electromagnetic forming than to form other shapes such as expanding and contracting tubes. Also, in electromagnetic forming of aluminum alloy panels for automobiles, the area of the formed part of the aluminum alloy plate is large (wide). As the area of the portion to be formed of the aluminum alloy plate is larger, the size of the coil required to have a size corresponding to the portion to be formed is also increased, and there is a problem that the production of the coil itself becomes difficult and expensive. For this reason, electromagnetic forming has not been applied to forming automotive aluminum alloy panels.
[0018]
The present invention has been made in view of such circumstances, and an object of the present invention is to form an aluminum alloy automobile panel in a shape portion that becomes stretched or deformed when pressed and formed. Another object of the present invention is to provide a method for forming an aluminum alloy automobile panel.
[0019]
[Means for Solving the Problems]
The gist of the method for forming an aluminum alloy automobile panel according to the present invention for achieving the above object is a method for molding an aluminum alloy automobile panel by press molding, and the shape that causes stretch flange deformation or contraction flange deformation when pressed. The molding of the portion is performed by electromagnetic molding.
[0020]
In the present invention, a shape portion such as a curved surface shape which is deformed by stretch flange deformation or contraction flange deformation during normal press forming is selected, and finish forming or preliminary forming of the limited shape portion is performed by electromagnetic forming. Other easily press-formed panel parts are basically formed by normal press forming. As described above, by performing the electromagnetic molding in combination with the normal press molding, the area and the size of the panel portion to be electromagnetically formed are limited, and the size of the coil corresponding to the outer panel portion to be formed is also limited. This facilitates electromagnetic forming and coil production. This makes it possible to apply electromagnetic forming to an aluminum alloy automobile panel and to form the shaped portion.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the method for forming an aluminum alloy automobile panel of the present invention will be described with reference to the drawings.
[0022]
2 (a), (b) and (c) show a method of forming the outer panel molded product of FIG. 1 (a) by electromagnetic molding after press molding. First, FIG. 2A shows a normal press forming method prior to electromagnetic forming, and is a cross-sectional view of a press forming apparatus including a mold. In the press forming shown in FIG. 2A, the panel molded product 1 shown in FIG. 1A except for curved portions such as the curved side wall portions 3a and 3b and the curved flange portions 4a and 4b which are curved in a large arc shape. Press-forming into a pre-molded product having a substantially HAT shape as shown in a perspective view in b). In FIG. 1 (b), circled portions are portions corresponding to the arc-shaped curved side wall portions 3a, 3b formed by electromagnetic molding described later.
[0023]
In FIG. 2A, a die (die) 6 has a forming part 6a of a product part 2 of the panel molded product 1 and a die face 6b forming a flange part 4 around the product part. Are provided with draw bead portions 9a and 9b.
[0024]
The panel material (blank) 5 made of an aluminum alloy plate is applied with a wrinkle suppressing force by a blank holder 8 at the time of molding, and is provided with a material passage resistance by draw beads 9a and 9b. 6a, and a substantially HAT type pre-molded product shown in FIG. 1 (b) is press-molded.
[0025]
Next, FIGS. 2B and 2C show a case where the arc-shaped curved side wall portions 3a and 3b of the outer panel molded product of FIG. 1A are partially formed by electromagnetic forming. First, as shown in a partially enlarged view in FIG. 2 (b), a punch 7 having a molding surface 7a having an arcuate curved shape is provided on a portion 3a corresponding to the arcuate curved side wall portion of the panel material 5. Are provided close to each other from inside.
[0026]
Then, as shown in FIG. 2C, the electromagnetic forming coil 10a having a shape corresponding to the portion 3a corresponding to the arc-shaped curved side wall portion is moved outward from the portion 3a corresponding to the arc-shaped curved side wall portion. Is provided close to. Then, electric energy is applied to the electromagnetic forming coil 10a to deform the formed portion of the panel material 5 in the direction of the arrow, and the deformed panel formed portion is pressed against the forming surface 7a of the punch 7 to form the outer panel. The arcuate curved side wall portions 3a and 3b of the product are formed. The portion 3b corresponding to the other arcuate curved side wall portion is similarly electromagnetically formed.
[0027]
According to the electromagnetic forming in combination with such press forming, the arc-shaped curved side wall portion is not deformed at a low speed as in the conventional press forming, but an extremely high-speed stretch flange deformation occurs. No crack X 1 occurs in the part. Further, since the molding is performed using a mold such as the molding surface 7a of the punch 7, the shape accuracy is high. In addition, since the entire press-formed product is not electromagnetically formed but only partially electromagnetically formed, the coil required to have a size corresponding to the portion to be formed can be relatively small, and the coil itself can be manufactured. Is easy, has a long life and is inexpensive.
[0028]
Here, the coil 10a shown in FIG. 2 (c) has an area (size) corresponding to the panel portion to be formed and a substantially rectangular shape. When the area of the coil 10a is smaller than the panel portion to be molded, the outer panel molded product is not accurately formed with respect to the designed product shape. Conversely, if the size is too large, the outer panel molded product will not have the same shape accuracy as the molded product design shape, making it difficult to manufacture the coil and shortening the coil life.
[0029]
The coil 10a is provided close to the surface of the panel 5 as shown in FIG. If the distance (spacing) between the coil 10a and the surface of the panel 5 is too long (large), the electric energy applied to the coil 10a is lost without being efficiently used for forming (deforming) the panel portion, and the molded product is lost. The shape accuracy of the panel molded product with respect to the design shape is not high.
[0030]
On the other hand, the molding surface 7a of the punch 7 serving as a mold is also provided close to the opposite surface side of the panel 5. If the distance (spacing) between the molding surface 7a and the surface of the panel 5 is too large (large), the deformed panel portion is deformed by the input of electric energy to the coil 10a (the molding surface 7a of the punch 7). ) Is not pressed with a large pressing force. As a result, the shape accuracy of the panel molded product with respect to the design shape of the molded product is not high.
[0031]
In addition, as a result of not being pressed with a large pressing force, the pressed molded panel portion does not work harden. As a result, the strength of the molded panel portion cannot be increased, and the dent resistance of the molded panel portion cannot be improved. This work hardening function becomes more important as the required characteristics of the dent resistance for the panel become higher.
[0032]
In the electromagnetic forming according to the present invention, the size of the panel portion, the generated plate thickness, and the work accuracy of the formed portion are improved by performing the electromagnetic forming only once to improve the shape accuracy of the panel formed product with respect to the design shape of the formed product. The amount of electric energy input to the coil is preferably 7.3 kJ or more, although it depends on the molding conditions such as the amount of reduction, material properties, and the amount of input electric energy. If it is less than 7.3 kJ, the amount of electric energy applied to the coil per operation is small, so that a panel molded product satisfying dimensional accuracy and shape accuracy cannot be formed. In addition, it is more likely that the formed panel molded product portion is hardened by work, and the strength reduction due to the reduced thickness of the flange cannot be compensated.
[0033]
The reason why the electromagnetic forming of a plate described in the aforementioned Mechanical Engineering Research Institute Report No. 150 was difficult was that the amount of electric energy input per one time was about 7.2 kJ or less at most due to restrictions such as coils. This was largely due to the low level of
[0034]
In addition, in order to prevent softening of the formed metal member and promote work hardening, the series of electromagnetic forming in the present invention is preferably performed in a state where the sheet material is at room temperature (electromagnetic forming is performed at room temperature). However, the normal temperature, including room temperature, allows a temperature rise that does not soften. In addition, if the work hardening amount can be ensured after the shape accuracy is obtained, it is permitted to perform electromagnetic forming at a low temperature, such as a high temperature or a very low temperature, depending on a material or a member shape.
[0035]
Aluminum alloys used for molding in the present invention are generally used in applications such as this kind of structural material, and aluminum alloys such as 5000 series and 6000 series specified in AA to JIS standards have high formability and high strength. It is preferable because it has both functions. Al-Mg-based 5000-based aluminum alloys are preferable in that they have a large amount of work hardening during electromagnetic forming and high formability. Also, the Al-Mg-Si-based 6000 series aluminum alloy has artificial age hardening (baked hard property), which makes it easy to mold in a low proof stress state, and can increase the yield strength by artificial age hardening after molding. It is preferred in that respect. Of course, other aluminum alloys can be electromagnetically formed and can be selected according to the application and required characteristics.
[0036]
Here, the coil used for electromagnetic molding preferably has a planar shape corresponding to the panel molded part shape, such as a coil 10 shown in a cross section in FIG. A conductor element wire 11 having a square (or rectangular) cross section, buried in a plane and wound in a plane, an insulating material 12 wound outside the conductor element element 11 itself, and the outside of the conductor element element 11. And an insulating substance 13 disposed on the front side. Adjacent conductor strands 11 are closely contacted so that there is no gap, and the thickness of the insulating layer is uniform. Further, the wire surfaces are wound and arranged so as to be parallel. As these insulating substances, a fiber reinforced resin obtained by impregnating glass fibers with an epoxy resin or the like is preferably used.
[0037]
By the use of such a fiber reinforced resin and the above-mentioned respective insulators, and the arrangement of the conductor strands such as copper wires, the periphery of the conductor strands is reinforced, and even when subjected to a strong expansion force when energizing the coil. In addition, deformation of the conductor strand itself and damage to the insulating layer are reduced. Furthermore, since the conductor strands are arranged so that the surfaces of adjacent conductor strands are parallel to each other, there is no room for unnecessary voids to enter during resin impregnation and impairing the insulation.
[0038]
Next, a method for forming a flange in a through hole of the aluminum alloy panel will be described with reference to FIG. First, a method of providing a through hole in a panel is performed by a normal punching process shown in FIG. That is, as shown in the cross-sectional view of the pressing die in FIG. 4A, a shear (shear) load is applied to the aluminum alloy panel 21 after the press forming by the cooperation of the die 25, the punch 24, and the plate holder 26. In addition, a perforation process is performed to provide a predetermined diameter d (the diameter d of the punch 24) and a predetermined number of through holes 22. The diameter of the through hole 22 to be stamped is the diameter d of the punch 24, but is determined by the diameter of the hole required for mounting other structural parts. Also, the number and spacing of the through holes 22 are determined by the relationship with the required number and spacing of other structural components (including fastening jigs) such as the bolts to be attached.
[0039]
In FIG. 4A, c is a clearance between the inner diameter of the die 25 and the outer diameter of the punch 24. In this case, it is preferable that the clearance is in the range of 15 to 25% of the plate thickness of the aluminum alloy plate to be processed, more specifically, in the range of 20 to 25%. If the clearance is too small or too large, the distortion applied to the periphery of the through hole 22 during the punching process increases. If the clearance is too large, a defective shape such as a burr is likely to occur at the edge of the through hole 22 during the punching process.
[0040]
Further, various conditions of the press working die, such as the shoulder R (diameter) of the corner of the die 25 and the shoulder R (diameter) of the corner of the punch 24, are determined by selecting the clearance between the die and the punch, and the The conditions under which punching can be performed are appropriately selected according to the diameter d.
[0041]
Next, as shown in FIGS. 4B and 4C, the through hole 22 is expanded to form a small flange 23. This hole enlarging process is a preforming for forming the flange 23 to a required height h 2 by electromagnetic forming described later. Accordingly, the height of the flange 23 in this hole expanding process is set low so as not to cause the above-described cracking, and is set to a height which is easily set to a height h required by electromagnetic molding described later. The flange 23 shown in FIG. 4B has a reduced diameter portion (flange portion) 23a required for the fastening structure at the upper end, and the flange 23 shown in FIG. Having.
[0042]
Further, the flange of FIG. 4 (b) and the flange of FIG. 4 (c), which have been subjected to the hole expansion processing, are connected to the flange 23 having a predetermined height h as shown in FIGS. 5 (a) and 5 (b). Electromagnetic molding. The height h of the flange 23 depends on the required guide length of other structural components (including the fastening jig) such as the bolts to be attached, the length required for fixing or joining, or the required rigidity improvement of the aluminum alloy panel. Is determined.
[0043]
As shown in FIGS. 5A and 5B, an electromagnetic forming coil 10b having, for example, a circular shape corresponding to the flange 23 is provided close to the inside of the flange 23. Then, electric energy is applied to the electromagnetic forming coil 10b to deform the molded portion of the panel material 21 in the direction of the arrow, and the deformed panel molded portion is pressed against the molding surface 28a of the die 28 to form a flange. 23 is formed to have a predetermined height h and a shape.
[0044]
At this time, in the electromagnetic molding, the strain rate applied to the material of the flange deformed portion is extremely high as compared with the conventional hole expanding process. As a result, cracks that penetrate the plate thickness starting from the edge (end face) of the flange do not occur. In addition, not all of the hole expansion processing is performed by electromagnetic molding, but only partial electromagnetic molding, so that the amount of electric energy input per electromagnetic molding can be small, and the coil itself can be easily manufactured, and the life is long. And it becomes cheap.
[0045]
Also, in the present invention, the outer peripheral portion (contour portion) of the outer panel to be hemmed is not only a linear peripheral shape but also an arc-shaped (curved) peripheral shape having a constant radius of curvature. In this case, it can be applied instead of the conventional hemming. In other words, in the arc-shaped peripheral edge portion, at the time of hemming, the flange becomes a stretch flange or a shrinking flange, and the actual outer contour of the peripheral edge portion of the hemmed portion after the hemming is designed or assumed in advance. The outer contour of the periphery of the hem after the hemming will be slightly larger or smaller, and the R part will not be sharper than the original design shape. However, there is a problem that the shape accuracy is not high, such as that the arc shape is not.
[0046]
When the outer contour of the peripheral edge of the hem in such a panel is misaligned, the outer contour of the panel may be misaligned with the outer contour of another straight portion, or a hood, a fender, a door, a roof, and a trunk of an automobile may be displaced. The dimensional accuracy of the outer contour of the panel structure such as the lid is reduced, and the panel structure has a large adverse effect on assembly and joining with other panels and frames.
[0047]
On the other hand, in the normal hemming, in particular, the pre-hem process or the down-flange process, which causes the deformation of the stretch flange or the contraction of the flange, is replaced by electromagnetic forming, respectively or together. In this way, the 90 ° or 135 ° bending deformation of the panel end in the prehem process or the down flange process does not become the extension flange deformation or the contraction flange deformation, and the dimensional accuracy of the outer contour of the panel structure is reduced. Get higher. Then, after that, a conventional or ordinary flat hemming process or a rope hemming process may be performed to further bend and form by 180 °.
[0048]
【The invention's effect】
As described above, according to the present invention, by combining press molding and electromagnetic molding, stretch flange deformation or contraction flange deformation occurs in press molding, and a shape portion where molding failure is likely to occur, molding failure occurs. It can be molded without using. In addition, there is also an effect that the electromagnetic molding itself can be realized by the partial electromagnetic molding of the shape portion where the molding failure easily occurs. Further, since it is possible to form an aluminum alloy into a panel having a shape that is usually difficult to form, it is very significant that the use of the aluminum alloy can be expanded.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a press-formed product of a panel, in which (a) shows a press-formed product, and (b) shows an embodiment of a pre-formed product of (a).
FIGS. 2A and 2B are cross-sectional views showing modes of a molding method according to the present invention, in which (a) shows press forming and (b) and (c) show electromagnetic forming of the press-formed product of (a).
FIGS. 3 (a) and 3 (b) are cross-sectional views each showing a panel-expanded molded product.
FIG. 4 is a sectional view showing one embodiment of a forming method of the present invention, in which (a) shows one embodiment of punching (press forming), and (b) and (c) shows one embodiment of hole expanding (press forming). .
FIG. 5 is a cross-sectional view showing an embodiment of the electromagnetic molding of the present invention, following FIG. 4, in which (a) shows one embodiment of the forming flange, and (b) shows another embodiment of the forming flange.
[Explanation of symbols]
1: Panel molded product, 2: Molded product part, 3: Vertical wall part, 4: Flange part,
5: aluminum alloy blank, 6: mold, 7: punch, 8: plate holder, 9: bead,
10: electromagnetic coil, 11: conductor wire, 12: insulating material, 13: insulating material, 14: resin
21: Aluminum alloy panel, 22: Hole, 23: Flange, 24: Punch,
25: die, 26: plate holder, 27: punch, 28: flange

Claims (5)

A method of forming an aluminum alloy automobile panel by press molding, wherein the forming of a shape portion that undergoes stretch flange deformation or contraction flange deformation during press molding is performed by electromagnetic molding. Method. At the time of the electromagnetic molding, a coil having a shape corresponding to the shape portion that becomes the stretch flange deformation or the contraction flange deformation is provided close to one surface of the formed portion, and a mold forming surface of the panel is formed. Provided close to the other surface of the molded part, applying electric energy to the coil to deform the molded part of the panel, and pressing the deformed panel molded part against the mold molding surface 2. The method for forming an aluminum alloy automobile panel according to claim 1, wherein the shape portion is formed. The method for forming an aluminum alloy automobile panel according to claim 1 or 2, wherein the input electric energy at the time of the electromagnetic forming is 7.3 kJｋ or more. The method for forming an aluminum alloy automobile panel according to any one of claims 1 to 3, wherein the aluminum alloy is an Al-Mg-Si-based aluminum alloy. The method of forming an aluminum alloy automobile panel according to any one of claims 1 to 4, wherein the formed panel portion is work-hardened to increase the rigidity of the panel.

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