JPH04237524A - Method for drawing metallic sheet - Google Patents

Abstract

PURPOSE:To increase forming speed, to improve productivity and further to ameliorate various physical properties of a drawn can by effectively preventing deformation to flattering generated when a metallic sheet is drawn by a punch and a die into a cup. CONSTITUTION:When the metallic sheet is drawn into a cup between the punch and the die, at least part of the place vertical to the rolling direction of the metallic sheet is drawn at a step surface in the direction vertical to the joint between the bottom part and the side wall part of the cup so that it is located inside the diametrical direction as compared with a part located in the rolling direction of the metallic sheet.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a method for drawing metal plates, and more specifically, it prevents the drawing cup from becoming flat during processing, thereby improving drawing workability and various characteristics of the drawn can. This invention relates to a molding method that can improve

0002

[Prior Art] Conventionally, a metal material such as an aluminum plate or a surface-treated steel plate is subjected to a one-stage or multi-stage drawing process between a drawing die and a punch to form a body with no seams on the sides and a seam on the body. It is widely practiced to produce cans with seamless sides and an integrally connected bottom. In multi-stage drawing or drawing-deep drawing, a metal plate is formed into a shallow drawn cup with a relatively large diameter, and then formed into a deep drawn cup with a relatively large diameter. Further, shaping into a cup is generally performed by adjusting the stroke of the punch so that a flat plate portion called a flange remains at the open end of the cup.

0003

[Problem to be Solved by the Invention] However, if the cup is formed so as to leave a flange at the open end, the cup is removed from the punch between the punch and the die before the next forming stroke of the punch. In addition, it is necessary to transport the removed cup to the outside of the molding area, and the stroke of the punch must be adjusted so that the flange remains, resulting in a slow molding speed, which is still unsatisfactory in terms of productivity. It wasn't. Furthermore, since there remains an ear or flat plate portion at the upper end of the cup that is removed by trimming, there is still room for improvement in terms of effective use of the metal plate.

[0004] From this point of view, it is expected that drawing a metal plate into a flangeless cup between a punch and a die will increase the forming speed, improve productivity, and further reduce material costs. . However, the flangeless cup formed by the above-mentioned drawing method has a flat and greatly distorted shape, which makes it difficult to transfer and position the cup.
It was recognized that an important problem occurred during operations such as inserting a punch during redrawing.

That is, the deformation of this cup into a flat shape is as follows:
This is based on the anisotropy of the physical properties of the metal plate, and the cup side wall portion that corresponds to the rolling direction deforms in the direction of decreasing diameter, that is, inward, while the cup side wall portion that corresponds to the direction perpendicular to the rolling direction expands in diameter. It was confirmed that flattening occurs by deforming in the direction of deformation, that is, outward. Furthermore, as the side wall portion becomes flattened, the bottom portion is also deformed into a warped shape. If such deformation occurs, it may become difficult to sit on the conveying member, the engagement with jigs, gripping tools, fixing members, punches, dies, etc. may not be carried out smoothly, or accurate positioning may become difficult. Furthermore, when these members come into contact with the cup, there is a tendency for the contact portion of the cup to be deformed and the resin protective coating to be damaged.

[0006] The above deformation was first observed when drawing a metal plate into a flangeless cup, and when forming a metal plate into a flanged cup, the opening end of the side wall is fixed with a flat flange. Because of this, such deformation into a flat shape is hardly recognized. however,
In the latter case, residual stress exists in the cup side wall due to the anisotropy of the physical properties of the metal plate, and a similar deformation occurs when the flange is cut off.

[0007] Accordingly, an object of the present invention is to provide a method for effectively preventing flattening deformation that occurs when a metal plate is drawn into a cup using a punch and a die. Another object of the present invention is to prevent flattening deformation caused by the anisotropy of the physical properties of metal plates, increase forming speed, improve productivity, and improve various physical properties of drawn cans. To provide a drawing method.

[0008]

[Means for Solving the Problems] According to the present invention, in order to achieve the above object, when a metal plate is drawn into a cup between a punch and a die, the connecting portion between the bottom and side wall of the cup is In the vertical cross section, drawing is performed so that at least a part of the part of the metal plate perpendicular to the rolling direction is located radially inward compared to the part of the metal plate located in the rolling direction.

In the present invention, it is preferable to draw the metal plate into a flangeless cup between a punch and a die in order to increase the forming speed and improve productivity. The metal plate may be an uncoated metal plate or a resin-coated metal plate, but according to the drawing method of the present invention, damage to the cup surface during molding is prevented, so the advantage is that a resin-coated plate can be used. It is also one of the.

The metal plate used may be a metal plate with large anisotropy of physical properties due to rolling, and has the following formula:

[Formula 2] In the formula, σmax is the maximum value of the tensile strength of the metal plate obtained by changing the pulling direction, σmin is the minimum value of the tensile strength of the metal plate obtained by changing the pulling direction, and σave is the maximum value of the tensile strength of the metal plate obtained by changing the pulling direction. It is an average value. It is preferable that the rolled metal sheet has a strength anisotropy value (R) defined as 1.5% or more, particularly 3 to 20%. Also,
On the cross section of the connection part including the central axis of the cup, the length of the outline of the flat plate part and the connection part at the point located in the rolling direction of the metal plate is l0, and the length of the outline of the flat plate part and the connection part at the point located at right angles to the rolling direction of the metal plate is When the length of the outline of the flat plate portion and the connecting portion is l1, the ratio l1/l0 is preferably 0.9995 or less.

In a preferred embodiment of the present invention, the punch has a tip, a side wall, and a corner between the two, and a pair of notches extending from the tip to the corner in a direction perpendicular to the axis of the punch. Use a tool with a cutout groove in the tip that is perpendicular to the axis of the punch, or a line connecting the cutout of the punch or the direction of the groove of the punch and the rolling direction of the metal plate. Draw forming in a positional relationship where the and are almost at right angles.

0012

[Operation] When drawing a metal plate into a cup between a punch and a die, the portion perpendicular to the rolling direction of the metal plate is By drawing so that at least a part of the metal plate is located radially inward compared to the part located in the rolling direction, flattening deformation caused by the anisotropy of the physical properties of the metal plate can be prevented, and punch and die This is based on the knowledge that it is possible to manufacture a cup with a shape that almost exactly corresponds to the shape of the cup.

[0013] Metal plates for can manufacturing are manufactured by rolling metal, but these metal plates have anisotropy in physical properties, where the strength in the rolling direction is generally smaller than the strength in the direction perpendicular to the rolling direction. There is sex. When this metal plate is drawn, it deforms into a flat shape because, as already pointed out, the side wall portion of the cup that coincides with the rolling direction deforms in the direction of decreasing diameter, that is, inward, while the part that is perpendicular to the rolling direction deforms. This is because the cup side wall portion that corresponds to the rolling direction is deformed in the direction in which the diameter increases, that is, to the outside.
This seems to be because the bending effect at the connection part is alleviated in the part in the direction perpendicular to the rolling direction, and the part tries to return to its original state.

In FIG. 1 (bottom view) and FIG. 2 (enlarged sectional view showing the X-X and Y-Y cross sections of FIG. 1 superimposed) for explaining the principle of the present invention, this aperture cup 1 has the following features: This is a flangeless cup formed by drawing and drawing a metal material, and consists of a bottom part 2, a side wall part 3, and a connecting part 4 between them. In the figure, the XX direction indicates the rolling direction of the metal, and the Y-X direction indicates the rolling direction of the metal.
-Y direction indicates a direction perpendicular to the rolling direction, and in FIG. 2, a solid line X indicates a cross section of a portion coincident with the rolling direction, and a dotted line Y indicates a section perpendicular to the rolling direction. In the present invention, in the vertical cross section of the connecting portion 4, at least a part of the portion Y perpendicular to the rolling direction of the metal plate is located radially inward compared to the portion X located in the rolling direction of the metal plate. Draw and form.

That is, as an example, the bending start point 5Y of the portion Y located on the bottom surface is located radially inward than the bending start point 5X of the portion X, and the bending end point of the portion Y located on the side wall surface. 6Y is located above the bending end point 6X of portion X in the height direction, or is located at the same position. By doing this, the cross section 5Y-6Y of the connecting portion of the portion Y perpendicular to the rolling direction is located radially inward compared to the cross section 5X-6X of the connecting portion of the portion X located in the rolling direction. . In such a state, paying attention to the length of the connecting part and the bottom contour on the cross section in the X-X direction and the cross section in the Y-Y direction, calculate the length of the arc 5X-6X, the length of the straight line 5X-5X', and the arc The total length of 5X'-6X' is l0, arc 5Y
-6Y length and straight line 5Y-5Y' length and arc 5Y'-
If the total length of 6Y' is l1, l0>l0 is always satisfied, and if the ratio l0/l1 is taken, l1/l0<1. By providing such a connection structure to the portion Y perpendicular to the rolling direction of the metal plate, flattening of the cup can be prevented because the bending at the connection portion is performed with a large average radius of curvature. This seems to be because the bending stress is dispersed, so there is less residual stress trying to return to the original state.

According to the present invention, it is possible to prevent the side wall from becoming flattened and the bottom from becoming warped.
, improves seating on the conveying member, smoothly engages with jigs, gripping tools, fixing members, punches, dies, etc., enables more accurate positioning, increases molding speed, and improves productivity. be able to. Furthermore, during transfer, positioning, post-processing, etc. of the cup, the contact part of the cup may be deformed or
It is possible to reduce the tendency of the resin protective coating to be damaged and to improve the various physical properties of the squeeze can. In the present invention,
Since deformation of the cup is prevented even when the cup does not have a flange, it is possible to draw and form a metal plate into a cup without a flange between a punch and a die, which further increases the drawing speed. This makes it possible to increase productivity.

[0017] Also, on the cross section of the connection part including the central axis of the cup, the length of the outline of the flat plate part and the connection part at a point located in the rolling direction of the metal plate is defined as 10, and the length of the outline of the flat plate part and the connection part at a point located in the rolling direction of the metal plate is defined as 10, and When the length of the outline of the flat plate part and the connecting part at the location located at is l1, the ratio of l1/l0 is 0.9995
It is better if it is below. In a preferred embodiment of the present invention, the punch has a tip, a side wall, and a corner between the two, and a pair of notches are formed from the tip to the corner in a direction perpendicular to the axis of the punch. Use a punch with a notch in the tip or one with a notch in the direction perpendicular to the axis of the punch, and make sure that the line connecting the notch of the punch or the direction of the groove of the punch and the rolling direction of the metal plate are approximately the same. Draw and form at right angles. These punches have the advantage of being easy to process and having excellent drawability.

[0018]

Preferred Embodiments of the Invention (Metallic Material) In the present invention, various surface-treated steel plates and light metal plates such as aluminum are used as the metal plate. The surface-treated steel sheet may be a cold-rolled steel sheet, or it may be subjected to secondary cold rolling after annealing, and subjected to one type of surface treatment such as galvanizing, tin plating, nickel plating, electrolytic chromic acid treatment, chromic acid treatment, aluminum plating, etc. Two or more kinds of methods can be used. An example of a suitable surface-treated steel sheet is an electrolytic chromic acid treated steel sheet, in particular a steel sheet with a surface treatment of 10 to 20
0mg/m^2 metallic chromium layer and 1 to 50mg/m^
2 (metallic chromium equivalent), and this material has an excellent combination of coating film adhesion and corrosion resistance. Another example of a surface-treated steel sheet is a hard tin plate with a tin coating amount of 0.5 to 11.2 g/m^2. This tin plate is 0.5 to 1 in terms of metal chromium.
00 mg/m^2 of chromic acid or chromic acid/phosphoric acid treatment is desirable.

As the light metal plate, an aluminum alloy plate is used in addition to a so-called pure aluminum plate. The aluminum alloy plate with excellent corrosion resistance and workability is Mn0.2.
to 1.5% by weight, Mg 0.8 to 5% by weight, Zn
The composition is 0.20 to 0.3% by weight, Cu 0.15 to 0.45% by weight, and the balance Al. These light metal plates are also preferably subjected to chromic acid treatment or chromic acid/phosphoric acid treatment such that the amount of chromium is 3 to 300 mg/m^2 in terms of metal chromium.

The thickness of the metal plate varies depending on the final can body diameter and the type of metal, but in the case of surface-treated steel plate, it is 0.08
0.24 mm, especially 0.12 to 0.17 mm in the case of thin steel plates and aluminum plates, 0.1 to 0.4 mm,
In particular, by selecting a thin aluminum plate having a predetermined thickness from among thin aluminum plates of 0.14 to 0.3 mm, a can having a predetermined strength can be obtained. The present invention has the advantage that it can be applied to a metal plate that has undergone a high degree of rolling treatment to produce a drawn container that does not have a tendency to flatten and deform. By using materials within the above-mentioned range, it is possible to manufacture a squeeze can that is thin but has high strength.

(Protective coating) In the present invention, a protective coating of resin is applied to the metal plate prior to drawing, and it is remarkable that the protective coating layer is not damaged even if this is subjected to one or multiple drawing operations. This is a great advantage. The protective coating is formed by applying a protective coating or by laminating a thermoplastic resin film.

As protective coatings, any protective coatings made of thermosetting and thermoplastic resins, such as modified epoxy coatings such as phenol-epoxy coatings and amino-epoxy coatings, such as vinyl chloride-vinyl acetate copolymers, vinyl chloride; - Vinyl or modified vinyl paint such as partially saponified vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, epoxy modified, epoxy amino modified, or epoxy phenol modified vinyl paint: Acrylic resin Paint system: Synthetic rubber paints such as styrene-butadiene copolymer may be used alone or in combination of two or more.

These paints can be applied in the form of organic solvent solutions such as enamels or lacquers, or in the form of aqueous dispersions or solutions, such as roller coating, spray coating, dip coating, electrostatic coating, electrophoretic coating, etc. Applied to metal materials in shapes. Of course, if the resin paint is thermosetting, the paint may be baked if necessary. From the viewpoint of corrosion resistance and processability, the protective coating film preferably has a thickness (dry state) of generally 2 to 30 μm, particularly 3 to 20 μm. Moreover, in order to improve processability, various lubricants can be included in the coating film.

[0024] As the thermoplastic resin film used for lamination, polyethylene, polypropylene, ethylene-
Propylene copolymer, ethylene-vinyl acetate copolymer,
Olefin resin films such as ethylene-acrylic ester copolymer and ionomer: Polyester films such as polyethylene terephthalate, polybutylene terephthalate, and ethylene terephthalate/isophthalate copolymer: nylon 6, nylon 6,6, nylon 11, nylon 12, etc. Examples include polyamide film, polyvinyl chloride film, polyvinylidene chloride film, and the like. These films may be unstretched or biaxially stretched. Its thickness is generally 3 to 50 μm
, especially preferably in the range of 5 to 40 μm. The film is laminated onto the metal plate by a heat fusion method, dry lamination, extrusion coating method, etc. If the adhesiveness (heat fusion property) between the film and the metal plate is poor, for example, urethane-based Adhesives, epoxy adhesives, acid-modified olefin resin adhesives, copolyamide adhesives, and copolyester adhesives can be interposed.

(Preferred laminate) In the present invention,
As a film to be laminated to a metal plate, a film containing ethylene terephthalate units as a main component, containing a small amount of other ester units, and having a melting point of 170 to 235°C, particularly 180 to 235°C.
It is preferred to use a biaxially stretched film of copolyester at 30°C. In other words, since this copolymerized polyester is mainly composed of ethylene terephthalate units, it has excellent mechanical strength and workability, and can be subjected to advanced drawing and deep drawing (re-drawing) processing while coated on a metal plate. becomes. Furthermore, polyester containing ethylene terephthalate units as a main component has excellent barrier properties against corrosive components compared to other polyesters, and cans having an inner surface coated with this film have the advantage of excellent corrosion resistance. This copolyester also contains a small amount of ester units other than ethylene terephthalate, which brings about good results in terms of lamination workability and peeling resistance. Polyester (PET) consisting of ethylene terephthalate alone generally has a melting point of 257°C, but by including a copolymerized ester component, the melting point of this film is lowered to the above range, and it can be used as a metal plate. To enable lamination without melting a tin plating layer even when using tinplate. In addition, by introducing the copolymerized ester component, it is possible to lower the ultimate crystallinity and crystallization rate, which, together with lowering the melting point, makes it possible to lower the internal stress remaining in the laminate. . This copolyester film is preferably biaxially stretched, and by biaxially stretching the copolyester film, the stiffness of the film becomes stronger and lamination becomes easier. Furthermore, since the polyester of the film is molecularly oriented in biaxial directions, it also has the advantage of being difficult to form lamellae (spherulites) even when heated below its melting point. This copolymerized polyester is
Generally, 70 mol% or more, especially 75 mol% or more of the dibasic acid component in the copolymerized polyester consists of a terephthalic acid component, and 70 mol% or more, especially 75 mol% or more of the diol component consists of ethylene glycol, and the dibasic acid Ingredients and/or
or 1 to 30 mol% of the diol component, especially 5 to 25
It is preferred that the mole percentage consists of dibasic acid components other than terephthalic acid and/or diol components other than ethylene glycol. Examples of dibasic acids other than terephthalic acid include aromatic dicarboxylic acids such as isophthalic acid, phthalic acid, and naphthalene dicarboxylic acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; succinic acid, adipic acid, sebacic acid, dodecanedioic acid, etc. one or two aliphatic dicarboxylic acids;
Diol components other than ethylene glycol include propylene glycol, 1,4
One or more of -butanediol, diethylene glycol, 1,6-hexylene glycol, cyclohexanedimethanol, ethylene oxide adduct of bisphenol A, etc. can be mentioned.

The copolyester used should have a molecular weight sufficient to form a film, for which it should have an intrinsic viscosity (I.V.) of 0.55 to 1.9 dl/g, especially 0.65 to 1. A value in the range of .4 dl/g is desirable. The degree of biaxial orientation of the copolyester film can be confirmed by polarized fluorescence, birefringence, density gradient tube density, etc., but in this aspect of the invention, the copolyester film is 1.37g/ It is desirable that the molecules are oriented so as to have a density of 1.37 g/cm^3 or more, particularly 1.37 g/cm^3 or more.

It is generally desirable that the surface of the biaxially oriented copolyester film be subjected to a corona discharge treatment before bonding. The degree of corona discharge treatment is such that the wetting tension is 44
It is desirable that it be dyne/cm or more. In addition, it is also possible to perform adhesion-improving surface treatments known per se such as plasma treatment and flame treatment on the film, or adhesion-improving coating treatments such as urethane resin-based or modified polyester resin-based coatings.

As a primer for the copolyester film, resol-type phenol-aldehyde resins derived from various phenols and formaldehyde,
Phenol consisting of bisphenol type epoxy resin
Epoxy paint, especially phenol resin and epoxy resin in a weight ratio of 50:50 to 5:95, especially 40:60.
A paint containing the above-mentioned components in a weight ratio of 10:90 to 10:90 is preferably used.

(Drawing) According to the present invention, the metal plate is sheared into a shape such as a disk, and then the metal plate is sheared into a shape such as a disk, and then the metal plate is sheared with a punch and a die so that the vertical cross-sectional shape at the connection part has the above-mentioned relationship. Draw and form in between. That is, any punch that provides the above-mentioned l1/l0 ratio at the connection part of the cup can be used, but as shown in FIG. a corner portion 13 between the tip portion 11 and the corner portion 13;
A pair of notches 14 are formed in a direction perpendicular to the axis of the punch.
Use a punch with a notch 1 formed on it.
It is desirable that the draw forming be performed in a positional relationship in which the line connecting 4 and the rolling direction of the metal plate are approximately perpendicular. It is generally desirable that the height (H) of the notch is in the range of 0.1 to 3 mm.

As shown in FIG. 4, the punch 10 includes a tip 11, a side wall 12, and a corner 1 between the two.
3, and a cutout groove 15 is provided in a direction perpendicular to the axis of the punch from the tip 11 to the corner 13, and the direction of the groove 15 of the punch and the rolling direction of the metal plate are approximately the same. It is also desirable to perform drawing forming in a perpendicular positional relationship. The height of the groove may also be in the same range as the notch.

[0031] The method of the present invention is carried out as a drawing process into a large diameter, shallow cup without ears, which is then subjected to one or multiple stages of deep drawing between a small diameter drawing punch and a drawing die. In this deep drawing step, the upper part of the cup side wall may be lightly drawn to make the wall thickness uniform. A lubricant can also be applied to the material during drawing. Of course, the drawing process can be performed at room temperature, but generally better molding workability is obtained when it is performed at a temperature of 20 to 70°C. The resulting squeeze cup is
After performing post-processing such as trimming and necking,
The can body is flanged and sealed to the can lid.

According to the method of the present invention, in the method of drawing a metal plate into a cup between a punch and a die, the metal plate is The metal plate is drawn into a cup using a punch and die by drawing so that at least a part of the part perpendicular to the rolling direction is located radially inward compared to the part of the metal plate located in the rolling direction. Although flattening deformation that occurs during forming can be effectively prevented, depending on the components, composition, or manufacturing conditions of the metal plate, rolling of the metal plate may occur in a cross section that includes the central axis of the connection between the bottom of the cup and the side wall. A greater effect may be achieved by drawing the metal plate so that at least a part of the internal portion thereof is located radially inward compared to the portion of the metal plate located in the rolling direction. In that case, it is preferable to arrange the material and the punch so that the positional relationship between the material and the punch is optimal. Of course, the method of the present invention can also be carried out in the drawing step during the manufacturing process of drawn and ironed cans (DI cans). Furthermore, the method of the present invention can also be applied to the case of forming a cup without a flange part in re-drawing. In this case, a means is required to determine the positional relationship between the punch and the rolling direction of the rolled plate in the drawing cup at the previous stage.

[0033]

[Example] Example 1 Tin-free steel with a plate thickness of 0.5 mm and a heat quality of DR-9
A tensile test was carried out on a TFS plate according to a conventional method, and the tensile strength in each direction was measured.The minimum value was 59.9 kgf/
mm^2, the maximum value is 6 in the tensile strength in the direction perpendicular to the rolling direction.
6.2kgf/mm^2, average value is 63.0kgf/m
It was m^2. Therefore, the intensity anisotropy value (R) according to equation (1) was 10%. Thickness 2 on both sides of this steel plate
An organic coated steel plate was obtained by thermally bonding a 0 μm biaxially stretched polyethylene terephthalate film. Approximately 1 mg of white petrolatum was added to this organic coated steel plate as a lubricating oil for forming.
/dm^2 after coating on both sides, diameter 179mm
A disk was punched out, and drawn using a punch, die, and wrinkle suppressor. The diameter of the punch side wall portion at this time was 115 mm, and the drawing ratio expressed by the value of the diameter of the material and the diameter of the punch was approximately 1.56. The punch tip and its vicinity have the shape roughly shown in FIG. 3, and the details of the notch are shown in FIGS. 5(A) and 5(B) at Rp=6m.
m, H=0.3 mm, and W=14 mm. Said l1/
The value of l0 is 0.9989. Wrinkle holding force is 3to
It was set as n. Prior to forming, the punch was arranged so that the line connecting the pair of notches at the tip was perpendicular to the rolling direction of the material, and then forming was performed.

[0034] The cup formed under the above conditions has an almost perfect circular outline at the top of the side wall (mouth part), an inner diameter of about 114 mm in the direction coincident with the rolling direction, and a shape perpendicular to the rolling direction. The inner diameter in the direction is about 116mm and the difference is about 2
mm, and the cup bottom had an ideal shape with good flatness. Furthermore, when this cup was continuously conveyed at a rate of 100 cups per minute to a conveyor transport device and an insertion device for the next step, the re-squeezing step, the flow was very smooth and no trouble occurred. Furthermore, when the inner surface of the final product was inspected, the coating was completely maintained and no exposed metal was observed.

Example 2 After applying white petrolatum as a forming lubricant to both sides of the same organic coated steel plate as used in Example 1 at a rate of about 1 mg/dm^2, it was punched out into a disc with a diameter of 179 mm. , a punch, a die, and a wrinkle presser were used to perform drawing forming. The diameter of the side wall of the punch at this time was 115 mm, and the drawing ratio expressed as the ratio of the diameter of the material to the diameter of the punch was approximately 1.56. The tip of the punch and its vicinity have the shape roughly shown in Fig. 4, and the details of the shape of the notched groove part are shown in Fig. 6, Rp = 6 mm, D = 0.7 m.
m, L=102 mm. The value of l1/l0 is 0.
It is 9981. The wrinkle pressing force was 3 tons. Prior to molding, the grooves of the punch and the rolling direction of the material were arranged at right angles, and then molding was performed.

[0036] The cup formed under the above conditions has an almost perfect circular outline at the top of the side wall (mouth part), an inner diameter of about 114 mm in the direction coincident with the rolling direction, and a shape perpendicular to the rolling direction. The inner diameter in the direction is about 116mm and the difference is 2m
m, and the cup bottom had an ideal shape with good flatness. Furthermore, when this cup was continuously conveyed at a rate of 100 cups per minute to a conveyor transport device and an insertion device for the next step, the re-squeezing step, the flow was very smooth and no trouble occurred. In addition, when inspecting the inner surface of the final product,
The coating was completely maintained and no exposed metal was observed.

Example 3 A tensile test was carried out on an Al-Mn aluminum alloy rolled plate having a thickness of 0.26 mm according to a conventional method, and the tensile strength in each direction was measured. The tensile strength in the direction parallel to the rolling direction is 28.7 kgf/mm^2, and the maximum value is 29.7 kgf/mm in the direction perpendicular to the rolling direction.
m^2, the average value was 29.1 kgf/mm^2. Therefore, the intensity anisotropy value (R) according to equation (1) is 3.
It was 4%. A thickness of 20 μm is applied to both sides of this aluminum alloy plate.
An organic coated plate was obtained by thermally bonding the biaxially oriented polyethylene terephthalate film. Drawing forming was carried out in the same manner as in Example 1 except for using this organic coated plate. The contour of the molded cup is approximately a perfect circle at the top of the side wall (mouth area), and the inner diameter in the direction that coincides with the rolling direction is approximately 114.5 mm, and the inner diameter in the direction perpendicular to the rolling direction is approximately 114.5 mm. 115.5mm, the difference is about 1mm,
The bottom of the cup had an ideal shape with good flatness. The roundness of the side wall portion was well maintained, and the cup bottom had an ideal shape with good flatness. Furthermore, when this cup was continuously conveyed at a rate of 100 cups per minute to a conveyor transport device and an insertion device for the next step, the re-squeezing step, the flow was very smooth and no trouble occurred. In addition, when inspecting the inner surface of the final product,
The coating was completely maintained and no exposed metal was observed.

Comparative Example 1 After applying white vaseline as a molding lubricant to both sides of the same organic coated steel plate as used in Example 1 at a rate of about 1 mg/dm^2, a disc with a diameter of 179 mm was coated. Drawing molding was performed by punching, punching, dicing, and wrinkle suppressing. The diameter of the side wall of the punch at this time was 114 mm, and the drawing ratio expressed as the ratio of the diameter of the material to the diameter of the punch was approximately 1.56. The tip of the punch is a plane perpendicular to the central axis, and the connecting portion between the tip and the cylindrical surface has a constant radius of curvature Rp=6 in a cross section including the central axis. Therefore, this punch has an axially symmetrical shape with respect to the central axis. The wrinkle pressing force was 3 tons. In the cup formed under the above conditions, at the top of the side wall (mouth area),
Its profile is flat, with an inner diameter of approximately 110.5 mm in the direction of rolling, and an inner diameter of approximately 11 mm in the direction perpendicular to the rolling direction.
It was 7.5 mm, and the difference was approximately 7 mm, making it an approximately ellipse. Furthermore, the bottom was slightly curved in the rolling direction. Furthermore, when this cup was passed through a conveyor transport device and a device that inserts it into the next re-squeezing process, it exhibited somewhat unstable behavior during conveyor transport, and even fell off from the gripping tool during the re-squeezing process. Otherwise, poor engagement with the wrinkle suppressing tool frequently occurred, making continuous can making difficult.

[0039]

According to the present invention, when a metal plate is drawn into a cup between a punch and a die, in the vertical cross section of the connection between the bottom and the side wall of the cup, there is no difference in the rolling direction of the metal plate. By drawing so that at least a part of the perpendicular part is located radially inward compared to the part of the metal plate located in the rolling direction, it is possible to draw the metal plate into a cup with a punch and die. It can effectively prevent the flattening deformation that occurs, and furthermore, by preventing the flattening deformation that occurs due to the anisotropy of the physical properties of the metal plate, it increases the forming speed, improves productivity, and improves the various physical properties of the drawn can. It becomes possible to improve the

[Brief explanation of the drawing]

FIG. 1 is a bottom view of a squeeze cup shown to explain the principle of the invention.

FIG. 2 is an enlarged cross-sectional view of the X-X and Y-Y cross sections of FIG. 1 superimposed to explain the principle of the present invention.

FIG. 3 is a perspective view showing an example of the squeeze punch used in the present invention from the bottom side.

FIG. 4 is a perspective view showing another example of the squeeze punch used in the present invention from the bottom side.

FIG. 5 is an explanatory diagram for explaining an embodiment of the present invention.

FIG. 6 is an explanatory diagram for explaining an embodiment of the present invention.

[Reference numbers] 1 is the squeeze cup, 2 is the bottom, 3 is the side wall,
4 is a connection part, 10 is a punch, 11 is a tip part, 12 is a side wall part, 13 is a corner part between them, 14 is a notch part, 1
5 is the notched groove, X-X is the metal rolling direction, Y-Y is the direction perpendicular to the rolling direction, solid line X is the cross section of the part that coincides with the rolling direction, dotted line Y is the part perpendicular to the rolling direction, 5Y is The bending start point of part Y, 5X is the bending start point of part X, 6Y is the bending end point of part Y, and 6X is the bending end point of part X.

Claims (7)

[Claims] Claim 1: In a method of drawing a metal plate into a cup between a punch and a die, in a vertical cross section of the connection between the bottom and the side wall of the cup, at least a portion perpendicular to the rolling direction of the metal plate is formed. A method for drawing a metal plate, characterized in that drawing is performed so that a portion of the metal plate is located radially inward compared to a portion of the metal plate located in the rolling direction. 2. The method of drawing a metal plate according to claim 1, wherein the metal plate is drawn into a flangeless cup between a punch and a die. 3. The method of drawing a metal plate according to claim 1, wherein the metal plate is a resin-coated metal plate. Claim 4: The metal plate has the following formula: [Formula 1] where σmax is the maximum value of the tensile strength of the metal plate obtained by changing the pulling direction, and σmin is the tensile strength of the metal plate obtained by changing the pulling direction. and σave is the average value of the tensile strength. 2. The method for drawing a metal plate according to claim 1, wherein the metal plate is a rolled metal plate having a strength anisotropy value (R) of 1.5% or more. 5. On the cross section of the connection portion including the central axis of the cup, the length of the outline of the flat plate portion and the connection portion at a location located in the rolling direction of the metal plate is defined as l0, and the length is perpendicular to the rolling direction of the metal plate. 2. The metal plate draw forming method according to claim 1, wherein the ratio of l1/l0 is 0.9995 or less, where l1 is the length of the outline of the flat plate part and the connecting part at the location located at . 6. A punch having a tip, a side wall, and a corner between the two, and a pair of notches extending from the tip to the corner in a direction perpendicular to the axis of the punch. 2. The method of drawing a metal plate according to claim 1, wherein drawing is performed in a positional relationship in which a line connecting the notches of the punch and the rolling direction of the metal plate are substantially perpendicular to each other. 7. The punch has a tip, a side wall, and a corner between the two, and a cutout groove is provided from the tip to the corner in a direction perpendicular to the axis of the punch. 2. The method of drawing a metal plate according to claim 1, wherein drawing is performed in a positional relationship in which the direction of the groove of the punch and the rolling direction of the metal plate are substantially perpendicular.