JPS6042099B2 - Can body and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a can body formed from a metal plate and a method for manufacturing the same, and more particularly to a can body formed from a metal plate, which has flanges on both opening edges. and its manufacturing method.

Recently, due to advances in rolling technology, plate thickness has increased from 30 to 150 μm.
So-called ultra-thin metal plates (in this specification, a plate thickness of 30 to 150 μm is referred to as ultra-thin) have come to be stably manufactured.

Therefore, from the viewpoint of saving material flow and reducing weight, the body of three-piece cans, such as beverage or food cans or art cans, has a plate thickness of 150 to 320μ (in this specification,
Attempts have been made to manufacture metal plates from ultra-thin metal plates instead of so-called average-thick metal plates, which have a thickness of 150 to 320 microns (referred to as ordinary thickness). In general, it is possible for a metal plate that has been rolled to an ultra-thin thickness to compensate for the decrease in strength due to the reduction in plate thickness by increasing the strength to some extent through cold rolling. The can body can have sufficient strength as a can body for cans that require considerable strength, such as cans for beer or carbonated beverages.

However, a metal plate rolled to an extremely thin thickness is hardened by cold rolling, resulting in a considerable decrease in ductility. An important problem to be solved is cracking when flanging edges. In order to solve this problem, it was first proposed to increase the ductility by annealing the entire ultra-thin metal sheet blank for manufacturing the can body.

However, when annealed, the strength decreases considerably, and a can body formed from an annealed ultra-thin metal plate blank does not have sufficient strength and may cause so-called can body buckling. Therefore,
As disclosed in Japanese Patent Application Laid-Open No. 50-871, only the opening edges of a can body formed from an ultra-thin metal plate blank are selectively annealed by heating to, for example, about 500°C.
Increasing the ductility of the opening edges of the can body without reducing the strength of the main portion between the opening edges of the can body, and thus without creating the risk of the can body buckling. It was proposed to at least prevent the occurrence of cracks during flange processing.

However, if only the opening edges of the can body are locally heated, the can body will be distorted and deformed due to such local heating, and the quality of the can body will be significantly impaired. Put it away. Furthermore, in the can body formed from an ultra-thin metal plate and the manufacturing method thereof, the flanges formed by flanging both opening edges of the can body are extremely thin. When sealing a can lid or can bottom, it is quite difficult to seal the can lid or bottom properly.In many cases, it is necessary to paint or print the metal plate before forming it into a can body, but extremely thin metal plates, In particular, large ultra-thin metal plates that have not yet been cut into predetermined dimensions tend to flutter like thin paper when being painted or printed (flapping in the open area during baking), making it difficult to paint or print well. , etc., there are problems to be solved.

The present invention has been made in view of the above-mentioned facts, and its main purpose is to eliminate the above-mentioned drawbacks found in conventional can bodies manufactured from ultra-thin metal plates and methods for manufacturing the same. A new and excellent can body that satisfies the requirements for saving materials and reducing weight, has flanges, has sufficient ductility at both opening edges, and has sufficient strength as a whole, and a method for manufacturing the same. The goal is to provide the following.

According to the invention, the can body is formed from a metal plate,
A can body is provided in which both flanged opening edges are of average thickness, and the main portion between the opening edges is extremely thin. Further, according to the invention, there is provided a method for manufacturing a can body as described above from a metal sheet, wherein at least one pair of work rolls is provided, wherein one or both work rolls have at least one recess extending in the axial direction of the work rolls. A belt-shaped metal plate is passed through the plate and cold-rolled, and the part that passes through the pair of work rolls corresponding to the recess is medium thick, and the part that passes through the pair of work rolls corresponding to the recess is extremely thin. The strip-shaped metal plate is then cut to form a blank with normal thickness at both side edges and extremely thin between the two side edges, and the blank thus obtained is formed into a cylindrical body, and the cylindrical body is Both opening edges are flanged to form a can body in which the flanged opening edges are of average thickness and the main portion between the opening edges is extremely thin. A manufacturing method featuring features is provided.

Further, according to the present invention, in the method for manufacturing the can body as described above from a metal plate, both ends are cylindrical, and the main portion between the two ends has a convex portion and a concave portion in the axial direction. A first work roll having an alternating wave shape, and a recessed portion whose both ends are cylindrical and whose main portion between the two end portions corresponds to the convex portion and the recessed portion of the first work roll, respectively, in the axial direction. A strip-shaped metal plate is cold-rolled through at least one pair of work rolls consisting of a second work roll having a corrugated shape having alternating convex portions, and both ends of the work roll pair are cold-rolled. The both side edges passing between the parts are made to have a normal thickness, and the center part passing between the main parts of the work roll pair is made extremely thin in a wave shape, and the both side edges from the belt-shaped metal plate are made to have a normal thickness and the both side edges are made to have a normal thickness. A blank with extremely thin gaps is formed, the blank thus obtained is formed into a cylindrical body, and both opening end edges of the cylindrical body are flanged to form flanged double opening end edges. is medium thick,
There is provided a manufacturing method characterized in that the can body is formed into a can body in which the main portion between the opening edges is extremely thin.

In the can body according to the present invention as described above, firstly,
Since the main part of the can body other than the flanged edges of both openings, and therefore most of the can body, is extremely thin, it is possible to save material or reduce weight, etc., in the same way as with an ultra-thin can body. satisfy the request. Secondly, the opening edges to which flanging is applied are of normal thickness and therefore have sufficient ductility so that there is no risk of cracking during flanging. Third
In addition, since both opening edges have sufficient ductility, there is no need to anneal the entire can body or only a local part thereof, and therefore there is a risk that the strength of the main part of the can body may decrease and buckling of the can body may occur.
There is no problem of the can body being deformed due to distortion. Fourth, both opening edges are of normal thickness, and therefore the flange formed by flanging is of normal thickness, which makes it difficult to wrap the can lid or can bottom around the can body. Good seaming can be easily achieved. Furthermore, in the method for manufacturing a can body according to the present invention as described above, a large-sized metal plate or a metal plate blank of a predetermined size before cutting, which has locally average thickness portions, is used. Such metal or metal plate blanks are effectively prevented from fluttering due to the stiffness of the medium-thickness sections, and can therefore be easily painted or printed if desired. A more detailed explanation will be given below with reference to the accompanying drawings. The can body according to the present invention can be obtained by cold-rolling the main portion of a medium-thick metal plate 1 other than both side edges by an appropriate method, as shown in FIGS. 1 and 2, for example. 3 and 4 (the method for forming the blanks as shown in FIGS. 3 and 4 will be described in detail later).

The blank shown in FIGS. 3 and 4 consists of a main part 3 which is made extremely thin by further cold rolling the main part of a normal thick metal plate, and a main part 3 which is made extremely thin by further cold rolling the main part of a normal thick metal plate, and a main part 3 which is made extremely thin by further cold rolling the main part of a normal thick metal plate, and a Both side edges 2 remain the same thickness. The cross-sectional shape of the boundary between the medium-thick side edge portions 2 and the ultra-thin main portion 3 may be a tapered shape at a desired angle as shown in the figure, or a predetermined shape from the main portion 3 to each side edge portion 2. It may take any form such as a curved shape that continues with curvature. Such a blank is formed into a cylindrical shape so that both side edges 2 thereof become both open end edges, and is subjected to appropriate joining such as seam-fold joining, overlap joining, or welding, which is well known to those skilled in the art. When formed into a cylindrical body by this method, a cylindrical body 4 as shown in FIGS. 5-A and 5-B is formed.

The cylindrical body 4 shown in FIG. 5-A and FIG. 5-B has both open end edges defined by both side edges 2 of the blank, and has a normal thickness, and the main body between both open ends. It is defined from the main part of the blank 3 in the section and is extremely thin. As is well known, the cylindrical body 4 is flanged at both opening edges by press-fitting a suitable ring die into the opening edges, as shown in FIGS. 6 and 7, for example. is applied and shaped as shown in FIG. 8 to form a can body according to the present invention. Further, a can bottom and a can lid are wrapped around both flanged opening edges to form a can body as shown in FIG. 9. Next, a blank as shown in FIGS. 3 and 4, which is used to form a can body according to the present invention, is produced, in which both side edges are of average thickness and the main portion between both side edges is extremely thin. A preferred method for this will be described.

The first preferred method will be explained with reference to FIGS. 10 to 14. As shown in FIG. 12, for example, a strip-shaped medium-thick metal material 1 wound into a coil is sequentially unwound. Pass through one or more pairs (one pair in the case shown) of work roll pairs 6 and 6'', such work roll pairs 6 and 6
A medium-thick metal material 1 is cold-rolled to make it extremely thin.

- As shown in detail in FIG. 10, one work roll 6 of the pair of work rolls 6 and 6'' may include one work roll extending in the axial direction or a plurality of work rolls arranged at equal intervals in the circumferential direction (in the case shown in the figure, one work roll 6 extends in the axial direction). The distance between the circumferential surface of the work roll 6'' and the circumferential surface of the work roll 6'' is extremely thin, and the concave portions 7 on the circumferential surface of the work roll 6 correspond to the circumferential surface of the work roll 6''.
The distance between the work rolls 6″ and the circumferential surface of the work rolls 6″ corresponds to the normal thickness. Therefore, the work roll pairs 6 and 6 that rotate synchronously
The band-shaped metal material passed through the recess 7 of the work roll 6
Correspondingly, the part passing through the work roll pair 6 and 6'' is of normal thickness, and the part corresponding to the part other than the recess 7 of the work roll 6 and passing through the work roll pair 6 and 6'' is rolled and extremely thick. Therefore, as shown in FIGS. 13 and 14, portions 2 of average thickness exist at predetermined intervals, and portions 3 between these portions 2 of average thickness are extremely thin. Forced by the material. If such a material is cut transversely at the center of the medium-thickness portion 2 (i.e., at the position indicated by the dashed-dotted line in FIGS. If the blank is cut to a predetermined width), a blank as shown in FIGS. 2 and 3 can be obtained in which both side edges 2 are of average thickness and the main portion 3 between both side edges is extremely thin. In the illustrated example, the strip-shaped metal material 1 is rolled using a pair of work rolls 6 and 6'', but the strip-shaped metal material 1 is rolled gradually using a plurality of pairs of work rolls. It can also be rolled.

In such a case, since the so-called blank height C (Fig. 13) gradually increases due to gradual rolling, a pair of large-diameter work rolls with a correspondingly increased gap between recesses is used as the downstream work roll pair. It is necessary to use Further, instead of the work roll pair 6 and 6'' as shown in FIG. 10, a work roll pair 8 and 8'' as shown in FIG. 11 can also be used.

In the pair of work rolls 8, 8'' shown in FIG. 11, recesses 7'' having half the depth of the recesses of the work roll 6 shown in FIG. 10 are provided at corresponding positions on both sides. 10th
In the metal material passed through the work roll pair 6 and 6'' shown in the figure, the medium-thick part 2 protrudes from the extremely thin part 3 only on one side, but as shown in FIG. In the metal material passed through the pair of work rolls 8, 8'' shown, the medium-thick portion protrudes from the extremely thin portion 3 on both sides. Of course, recesses of the same depth as the recesses of the work roll 6 shown in FIG. An element of form that protrudes alternately on the upper and lower sides of a part. You can also get wood. Generally, in the can manufacturing process, the parts shown in Figs. 3 and 4 before being formed into the can body are
In many cases, the blank as shown in the figure or the material as shown in FIGS. 13 and 14 before being cut into blanks is subjected to the required painting or printing, but the blank as shown in FIGS. The blank as shown or the material as shown in FIGS. 13 and 14 before cutting into blanks,
In addition to the ultra-thin portion 3, there is a medium-thick portion 2, and the rigidity of the medium-thick portion effectively prevents so-called fluttering, so that painting or printing can be easily performed.

If there is no medium thickness part, especially if the large size material before cutting into blanks has no medium thickness part and is all very thin, it will flutter like tissue paper when painting or printing,
It is quite difficult to paint or print. Next, with reference to FIGS. 15 to 18, a blank as shown in FIGS. 3 and 4 is produced in which both side edges are of average thickness and the main portion between both J side edges is extremely thin. A second preferred method will now be described.

In a second preferred method, both ends are cylindrical;
A first work row whose main portion between both ends has a wave shape having alternating convex portions and concave portions in the axial direction. Similarly, both end portions are wave-shaped, and the main portion between the two end portions is wave-shaped with alternating concave portions and convex portions corresponding to the convex portions and concave portions of the first work roll in the axial direction. at least one pair of work rolls 11, 11 consisting of a certain second work roll;
is used.

The first work roll and the second work roll of this work roll pair correspond to a normal thickness at both end portions, and an extremely thin distance at their main portions. Therefore, as shown in FIG. 15, when a medium-thick metal plate is rolled through the pair of work rolls 11, 11, the pair of work rolls 11, 1
Both side edges 2 passing between both ends of 1 remain of normal thickness,
Central part 3'' passing between the main parts of the work roll pair 11, 11
An ultra-thin, corrugated metal plate having a cross-sectional shape as shown in FIG. 16 is obtained. Even if such a metal plate is manufactured into a can body with a corrugated central portion as it is, a can body with improved strength can be obtained, but if the central portion has a corrugated central portion 3″, a can body with improved strength can be obtained.
For example, if you flatten it by applying it to a pair of cylindrical rolls,
As shown in FIGS. 17 and 18, the blank has normal thickness on both side edges and an extremely thin main portion between the both side edges, that is, the third blank.
A blank similar to that illustrated in FIG. 4 is obtained. Of course, the main part of the blank can be made into a further corrugated shape to improve the strength of the can. In addition, Figures 10 to 1
In the method explained with reference to FIG. 4 and the method explained with reference to FIGS. 15 to 18, the medium thickness metal material that has been subjected to the primary cold rolling is further subjected to the secondary cold rolling. However, when performing such secondary cold rolling, it is preferable to perform the secondary cold rolling in a direction perpendicular to the direction of the primary cold rolling.

This is because, in general, when a metal material is first cold-rolled to produce a medium-thick metal material, as shown by arrow a in FIG.
Grain alignment occurs in the direction of cold rolling. When such a medium-thick metal material is subjected to secondary cold rolling in the same direction as the primary cold rolling, the grain arrangement produced by the primary cold rolling is loaded, and this causes the metal material to become Ductility is considerably reduced. However, when secondary cold rolling is performed in a direction perpendicular to the direction of primary cold rolling, as shown in FIG. In addition, a grain arrangement b due to the secondary cold rolling is generated, thereby reducing the decrease in ductility. In addition, this reduces the springback characteristics of the blank, making it easier to form it into a cylindrical body, making it easier to join it to the can body, and minimizing the amount of deformation of the formed can body. A high quality can body can be obtained.

[Brief explanation of the drawing]

1 and 2 are a side view and a plan view, respectively, of a medium-thick metal material. 3 and 4 are side and plan views, respectively, of a blank for forming a can body according to the present invention; FIGS. 5-A and 5-B are perspective views of the cylindrical body formed by the blanks shown in FIGS. 3 and 4. FIG. FIGS. 6 and 7 are cross-sectional views showing a method of flanging the opening edge of a cylindrical body. FIG. 8 is a simplified diagram of the can body of the present invention. FIG. 9 is a simplified diagram of a can body formed by wrapping a can bottom and a can lid onto a can body. 10 to 14 are simplified diagrams illustrating a first method for producing a blank for forming a can body according to the present invention from a medium-thick metal material. Figures 15 to 18 are
FIG. 3 is a simplified diagram illustrating a second method for producing a blank for forming a can body according to the invention from a medium-thick metal material; FIG. 19 and FIG. 20 are simplified diagrams showing the grain arrangement caused by cold rolling. 2... Average thickness opening edge portion, 3... Extremely thin main portion, 4... Cylindrical body.

Claims (1)

[Scope of Claims] 1. A can copper body formed from a metal plate, in which both flanged opening edges are of average thickness, and the main portion between the opening edges is extremely thin. A can body characterized by: 2. A method for manufacturing a can body from a metal sheet, which comprises cold rolling a strip metal sheet through at least one pair of work rolls, one or both of which has at least one recess extending in the axial direction. , the part that passes through the pair of work rolls corresponding to the recessed part is made to be of average thickness, and the part that passes through the pair of work rolls corresponding to the part other than the recessed part is made extremely thin, and the strip-shaped metal plate is cut. , forming a blank with normal thickness on both side edges and extremely thin between the both side edges, forming the blank thus obtained into a cylindrical body, and flanging both opening end edges of the cylindrical body, A manufacturing method characterized by forming a can body in which both flanged opening edges are of average thickness and the main portion between the opening edges is extremely thin. 3. A method for manufacturing a can body from a metal plate, wherein the first work roll has both ends having a cylindrical shape, and the main portion between the two ends has a corrugated shape having alternating convex portions and concave portions in the axial direction. and both ends have a cylindrical shape, and the main portion between the two ends has a wave shape that alternately has concave portions and convex portions corresponding to the convex portions and concave portions of the first work roll in the axial direction. Second
A belt-shaped metal plate is cold rolled through at least one pair of work rolls consisting of a pair of work rolls, and the work roll pair is passed between the both ends of the pair of work rolls, and the both side edges of the pair of work rolls are coated with a uniform thickness. The central part passing between the main parts of the belt is made extremely thin in a wave shape, and a blank is formed from the strip-shaped metal plate with medium thickness at both end edges and extremely thin between the two side edges, and the blank thus obtained. is formed into a cylindrical body, and both opening edges of the cylindrical body are flanged, so that the flanged opening edges are of average thickness, and the main part between the opening edges is of average thickness. A manufacturing method characterized by forming an extremely thin can body.