JP5295494B2 - DI can - Google Patents

Description

  The present invention relates to a DI can used for a can whose contents are sealed.

  Widely marketed are cans that are filled and sealed with beverages, etc., and cans that have flanges that can be wrapped around the open ends, and bottle cans that have caps screwed into the open ends. In circulation. A DI can used for such a can body is conventionally formed by drawing and ironing a plate material made of an Al alloy such as JIS3004 (AA3004) or JIS3104 (AA3104).

Conventionally, in the distribution process of a can body, for example, a fine hole generated when a sharp body contacts or collides with the body portion, or a fine particle generated by rubbing in a state where a foreign object is sandwiched between the can and the can. There was a problem that a so-called distribution pinhole (hereinafter referred to as a pinhole) such as a hole or breakage occurred and its contents leaked. As means for solving such a problem, for example, a configuration in which a resin film is disposed on a body part as shown in Patent Document 1 below is known.
JP-A-08-325514

  However, in the conventional can body, when the DI can is formed using the Al alloy as described above, the cross-sectional shape of the trunk portion orthogonal to the central axis O of the can body in a state where the contents are filled is substantially a perfect circle. As a result, the circumferential position of the body portion corresponding to 45 ° with respect to the rolling direction of the Al alloy sheet at the center of the bottom of the can is 45 °. Due to the anisotropy of the alloy material, there was a problem that the puncture strength was low and pinholes were liable to occur because the tensile strength and proof stress were lower than other parts of the same can.

  As a means for solving such a problem, it is difficult to generate pinholes by increasing the thickness of the body portion, and pinhole characteristics (in this specification, pinhole characteristics are generated by pinholes). However, in this case, parts may need to be replaced or readjusted for various manufacturing equipment, and the weight of the can also increases. It cannot be avoided that it increases.

As described above, the object is to secure the pressure resistance of the can body while suppressing the increase in the weight of the can body, and to easily and stably manufacture the can body. As a result of intensive studies by the inventors of the invention, the following findings were obtained.
With regard to materials and manufacturing methods for manufacturing DI cans, DI cans require, for example, material strength and pinhole characteristics related to pressure strength such as tensile strength as product characteristics, and the can body can be easily ironed. The characteristics (hereinafter referred to as DI moldability) and the characteristics (hereinafter referred to as neck moldability) indicating the ease of forming the neck portion of the DI can are required as characteristics for easily manufacturing the DI can. It was found that the characteristics of these are closely related to each other and are an obstacle to other characteristics.

That is, in order to increase the pressure resistance, which is a characteristic required for DI cans, in addition to the high material strength of the walls constituting the DI cans, it is preferable that they are sufficiently work-hardened. It is important to realize thinning. However, when the component strength is adjusted to increase the material strength itself, the DI moldability and neck moldability tend to decrease, and if the pressure resistance strength is secured by advancing work hardening, the can body When deformed, plastic deformation is likely to proceed, and the pinhole characteristics are deteriorated because the allowance of deformation (strain) allowed from the start of the deformation to the fracture is reduced after an external force is applied.
As described above, regarding work hardening, it can be said that the pressure resistance and the pinhole characteristics are contradictory properties, and the increase in the material strength itself deteriorates the moldability such as DI workability and neck workability.

On the other hand, when improving the DI moldability by reducing the squeezing rate in the manufacturing process, it is effective to reduce the squeezing rate by reducing the material thickness if the final thickness of the body is constant. However, reducing the thickness of the material leads to a decrease in pressure resistance at the bottom of the DI can.
Moreover, increasing the material strength or improving the work hardening in order to improve the pressure resistance strength results in a decrease in neck formability.

Also, if the material strength itself is reduced to improve the DI moldability and neck moldability, the pressure strength and pinhole characteristics are reduced, and if the pressure strength and pinhole characteristics are improved, the DI moldability and neck There is a mutually contradictory relationship that moldability is lowered.
From the knowledge obtained above, characteristics required for DI cans in terms of material properties and molding methods, such as material strength such as tensile strength, pressure strength and pinhole characteristics based on work hardening of materials, DI moldability and neck moldability Has been radically reviewed without being constrained by conventional manufacturing techniques.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a DI can that can prevent the occurrence of pinholes without increasing the manufacturing cost.

In order to solve the above problems, the present invention proposes the following means.
The invention described in claim 1 is a bottomed cylindrical DI can formed by drawing and ironing an aluminum alloy plate material, and the plate material has a final reduction ratio of 45% to 45% after intermediate annealing. 80% by Rutotomoni is plate thickness is less than 0.28mm or 0.24 mm, the drawing and ironing is ironing ratio is less than 51.4% 56.3%, the center axis O of the trunk portion The cross-sectional shape orthogonal to the above includes a convex portion protruding outward with a 90 ° interval in the circumferential direction of the barrel portion, and the circumferential position of the convex portion in the barrel portion is at the center of the bottom portion. The crossing angle with respect to the rolling direction of the said board | plate material is formed corresponding to 45 degrees, It is characterized by the above-mentioned.

  Invention of Claim 2 is DI can of Claim 1, Comprising: The radial direction distance of the said convex-shaped part from the central axis O formed in the can axial direction through the said bottom part is the said convex-shaped part. It is characterized by being formed larger in the range of 0.1 mm or more and 0.6 mm or less than the radial distance of other parts.

  Invention of Claim 3 is DI DI of Claim 1 or Claim 2, Comprising: The radial direction distance of the said convex-shaped part from the said center axis line O in the state with which the content was filled is the said It is characterized by being formed larger in the range of 0.05 mm or more and 0.15 mm or less than the radial distance of the part other than the convex shaped part.

  The invention described in claim 4 is the DI can according to any one of claims 1 to 3, wherein the aluminum alloy has a mass% of Si: 0.1 to 0.5%, Fe : 0.3-0.7%, Cu: 0.05-0.5%, Mn: 0.5-1.5%, Mg: 0.4-1.5%, Cr: 0.001-0 .10%, Zn: 0.05 to 0.30%, Ti: 0.05 to 0.10%, the balance being Al containing inevitable impurities.

The DI can according to the present invention is formed by subjecting an ingot to hot rolling, cold rolling, and annealing to a predetermined plate thickness, and subjecting the intermediate plate to cold finish rolling with a final reduction ratio of 45% to 80%. Since the aluminum alloy plate material is subjected to drawing ironing processing in which the ironing rate is 51.4% or more and 60.4% or less, the crossing angle with respect to the rolling direction of the plate material at the center of the bottom of the can is 45. A convex portion that extends in the can axis direction at an interval of 90 ° in the circumferential direction of the barrel portion and protrudes outward from the barrel portion is formed at a circumferential position of the barrel portion.
As a result, the puncture strength is increased and the pinhole characteristics are improved.

  The mechanism by which the convex portion is formed in the DI can according to the present invention is not clear, but the piercing strength is increased and the pinhole characteristics are improved because the crossing angle with respect to the rolling direction is 45 ° and the material strength By forming a convex part with a large curvature protruding outward in the circumferential position where the (tensile strength, proof stress) is the lowest, the inner part of the body when pressed inward in the radial direction This is presumably because the amount of plastic deformation from the beginning of dent to the breakage increases, so that the energy consumed by the plastic deformation and the corresponding stress increase.

  In addition, when the final reduction ratio of the aluminum alloy plate is 45% to 80%, sufficient strength is ensured by work hardening by DI processing, while work hardening is sufficiently lower than the work limit. Therefore, when the squeezing rate is 51.4% or more and 60.4% or less on this plate material, protrusions and sand are pushed into the convex part and work hardening proceeds. However, it is suppressed to a value smaller than the processing limit, and as a result, a margin for the processing limit is secured in the convex shape portion formed at a position where the intersecting angle with respect to the rolling direction, which is said to have the lowest material strength, is 45 °. It is presumed that breakage is suppressed.

Here, as shown in the flowchart of FIG. 4, the final rolling reduction is the thickness t1 of the intermediate plate (the plate before the cold rolling that is finally applied without sandwiching the annealing) and the final plate ( By the thickness (final plate thickness) tf of the plate material after the cold rolling described above,
Final rolling reduction = ((t1−tf) / t1) × 100 (%)
Calculated by
For example, in the case of performing intermediate annealing (IA) and final cold rolling (CF) after hot rolling (H) as shown in FIG. 4 (A), a stage where hot rolling (H) is performed, That is, the thickness of the plate before cold rolling (C1) is t1, and the thickness of the plate at the stage where the final cold rolling (CF) is completed is tf. In this case, if the temperature immediately after the end of hot rolling (H) is sufficiently high and recrystallization occurs spontaneously without intermediate annealing, intermediate annealing may be omitted. In addition, for example, when cold rolling (C1) and annealing are performed after hot rolling (H) as shown in FIG. 4B, the intermediate annealing (IA) is finally performed. The thickness of the plate is set to t1, and the thickness tf of the plate at the stage where the final cold rolling (CF) is completed. In this case, the flow indicated by a two-dot chain line in FIG. 4B may be performed a plurality of times, for example, 4 to 5 times, but it does not depend on the number of times.

  The DI can according to the present invention can prevent the occurrence of pinholes without increasing the manufacturing cost.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows a method for manufacturing a DI can shown as an embodiment of the present invention. FIGS. 2 and 3 are diagrams showing a DI can according to an embodiment. In FIG. , DI cans are shown.

  The DI can 10 has a size in the can axis direction, that is, a height of about 123.5 mm, an outer diameter of 65 mm or more and 67 mm or less, and the bottom portion 12 in the can axis direction of the trunk portion 11 as shown in FIG. A dome portion 12 a that is recessed inward is provided, and an outer peripheral edge portion of the dome portion 12 a is an annular convex portion 12 c that protrudes outward in the can axis direction of the body portion 11. The top of the annular convex portion 12c in the can axis direction is a grounding portion 12b that contacts the grounding surface L when the DI can 10 is placed on the grounding surface L so that the DI can 10 is in an upright posture. .

  The DI can 10 is formed into a bottomed cylindrical shape by squeezing and squeezing an aluminum alloy plate material W, and the cross-sectional shape of the body 11 perpendicular to the center axis O of the can is in the circumferential direction of the body 11. A convex portion 16 is provided that extends in the can axis direction with an interval of 90 ° and protrudes outward of the barrel portion 11. The circumferential position of the convex portion 16 in the trunk portion 11 is the same as that of the bottom portion 12. The crossing angles with respect to the rolling direction (0 ° or 180 ° direction in FIG. 3) of the sheet material W at the center (position where the central axis O passes) are the positions A1, A2, A3, A4 corresponding to 45 °.

When the DI can 10 is not filled with the contents, the convex portion 16 has a radial distance D1, D2, D3 from the central axis O within a range of 20 mm to 85 mm in height from the grounding portion 12b. D4 is formed larger in the range of 0.1 mm or more and 0.6 mm or less than the minimum value Dmin of the radial distance of parts other than the convex portion 16.
In the state where the DI can 10 is filled with the contents, the convex portion 16 has a radial distance D1, D2, D3 from the central axis O within a range of 20 mm to 85 mm from the grounding portion 12b. , D4 is larger than the minimum value Dmin of the radial distance of parts other than the convex portion 16 within a range of 0.05 mm or more and 0.15 mm or less.
Here, the state in which the contents are filled is a DI can 10 in which carbonated water is filled and a can lid is wound up so that the internal pressure of the can is 0.245 MPa at a room temperature of 20 ° C.
The central axis O is an axis that passes through the center of the bottom 12 and extends in the direction of the can axis. Specifically, it is an axis that passes through the center of the bottom 12 and the center of the opening of the DI can 10. is there.

In addition, the DI can 10 is made by printing and painting the outer surface of the body portion 11 including a printed portion such as character information using a polyester-based paint, and the DI can 10 subjected to the outer surface printing and the outer surface coating is 180 ° C. After forming a 50 mg / dm ² coating film by heating for 30 seconds, the inner surface of the DI can 10 was coated with an epoxy-based paint and heated to 200 ° C. for 60 seconds to be 40 mg / dm ² The outer surface printing, the outer surface coating, and the inner surface coating in which the coating film is formed are performed.

Next, a method for producing an aluminum alloy plate material used for forming the DI can 10 will be described.
First, a molten Al alloy having a composition according to JIS3004 (AA3004) or JIS3104 (AA3104) is degassed and inclusions removed by a conventional method, and the thickness is 550 mm, the width is 1.5 m, and the length is 4.5 m by semi-continuous casting. The slab is cast, and the slab is soaked, and then hot-rolled until the thickness becomes 6.5 mm, and then cold-rolled.

  And it hold | maintains in the temperature range of a heating rate of 100 degree-C / sec and 530-550 degreeC for 20 second, and anneals on the conditions of a cooling rate of 100 degree-C / sec, and is then cold-finished by a final reduction rate of 76%. As a result, a plate material (product coil) having a final plate thickness of 0.27 mm was obtained. In addition, all homogenization processes shall be 600 degreeC x 6 hours.

  After hot rolling, cold rolling and annealing are performed on an ingot of Al alloy to form an intermediate plate having a predetermined thickness, the intermediate plate is subjected to cold finish rolling with a final reduction ratio of 45% to 80%. Is formed on a plate material W having a final plate thickness (0.24 mm or more and 0.28 mm or less), and the after baking yield strength is 275 MPa to 284 MPa. Here, the after baking yield strength is a method for evaluating an Al alloy material, and is a yield strength by a tensile test after heating an Al alloy plate material at 210 ° C. for 10 minutes.

Next, a plate-shaped plate material (blank) W having a diameter of about 150 mm is formed by punching the plate material W.
Next, the plate material W is drawn into a cup-shaped body W1 by drawing with a cupping press.

Subsequently, the DI processing apparatus performs redrawing and ironing on the cup-shaped body W1 to form a bottomed cylindrical body W2. At this time, the ironing rate is 60.4%, and the ironing process is performed until the thickness of the thinnest portion of the body portion 11 becomes 0.105 mm.
The DI processing apparatus used for the redrawing ironing process includes a single redrawing die having a circular through hole for redrawing processing, and a plurality of sheets having circular through holes arranged coaxially with the redrawing die ( For example, three ironing dies (ironing dies) are coaxial with the ironing die, and can be fitted into the through holes of the respective ironing dies, and are movable in the axial direction. A cylindrical punch sleeve and a cylindrical cup holder sleeve fitted to the outside of the punch sleeve are provided.

  In the redrawing process by the DI processing apparatus, the cup W1 is disposed between the punch sleeve and the redrawing die, the cup holder sleeve and the punch sleeve are advanced, and the cup holder sleeve is moved to the end face of the redrawing die. The punch sleeve pushes the cup W1 into the through-hole of the redraw die while pressing the bottom surface to perform the cup pressing operation. As a result, a redrawn cup having a predetermined inner diameter is formed. Subsequently, the redrawn cup is passed through a plurality of ironing dies one after another and gradually ironed, and the side wall of the cup-shaped body is squeezed to extend the side wall to increase the side wall height and wall thickness. To form a bottomed cylindrical body W2.

The bottomed cylindrical body W <b> 2 that has been subjected to the ironing process has its bottom formed, for example, in a dome shape by the punch sleeve further pushing forward and pressing the bottom against the bottom molding die.
The bottomed cylindrical body W2 is cold-worked and hardened by the side walls being squeezed to increase the strength.

Next, the open end W2a of the bottomed cylindrical body W2 is trimmed.
Since the opening end W2a of the bottomed cylindrical body W2 formed by the DI processing apparatus is uneven and has a concavo-convex shape that undulates in the can axis direction, the opening end W2a of the bottomed cylindrical body W2 is By cutting and trimming, the height of the side wall in the can axis direction is made uniform over the entire circumference. In this way, the DI can 10 having a circular cross section having the body 11 and the bottom 12 is formed.

The DI can 10 thus formed is washed to remove lubricating oil and the like, then subjected to surface treatment and dried, then subjected to outer surface printing and outer surface coating, and then inner surface coating.
For example, the outer surface is coated and printed on the outer surface of the body of the DI can 10 using a polyester-based paint, and the DI can 10 that has been subjected to the outer surface printing and outer surface coating is heated at 180 ° C. for 30 seconds or more. The inner surface coating is performed by coating the inner surface of the DI can 10 with the outer surface coated using, for example, an epoxy-based paint and heating it at 200 ° C. for 60 seconds or longer.

Next, necking and flanging are performed on the DI can 10, and the neck portion 13 in which the body portion 11 of the DI can 10 is reduced in diameter toward the opening end, and the flange portion connected to the opening end of the neck portion 13. 14 is formed.
When performing necking, for example, by pressing the opening end side a plurality of times in the axial direction of the DI can 10 against an annular necking die arranged concentrically outside the opening end, the DI can The neck portion 13 is formed by sequentially reducing the diameter of the ten open ends.

In this embodiment, the plate material (blank) W has a disk shape with a diameter of 145 mm or more and 155 mm or less and a thickness of 0.24 mm or more and 0.28 mm or less, and the cup-shaped body W1 has a size in the axial direction of about The outer diameter is 42 mm and 42 mm.
Further, the redrawing ironing process applied to the cup-shaped body W1 is set so that the ironing rate when it is formed on the bottomed cylindrical body W2 is 51.4% or more and 60.4% or less.

Here, the ironing rate is
Ironing rate = (thickness of plate material W−thickness of body portion 11) / thickness of plate material W × 100 (%)
Is calculated by
The thickness of the trunk portion 11 is the thinnest portion of the trunk portion 11, for example, the thickness of the trunk portion 11 at a portion 60 mm away from the ground contact portion 12 b in the upper direction of the can axis. And the thickness of this trunk | drum 11 shall be 0.105 mm or more and 0.125 mm or less.

  Further, the aluminum alloy plate W is in weight percent (hereinafter the same), Si: 0.1-0.5%, Fe: 0.3-0.7%, Cu: 0.05-0.5%, Mn: 0.5 to 1.5%, Mg: 0.4 to 1.5%, Cr: 0.001 to 0.10%, Zn: 0.05 to 0.30%, Ti: 0.05 to It is preferable to use a composition composed of Al containing 0.10% and the balance containing inevitable impurities.

  Silicon (Si) forms a compound with Mg contained at the same time, and acts as a solid solution hardening, precipitation hardening, dispersion hardening action, and forms an intermetallic compound with Al, Mn, Fe, etc. Demonstrates the effect of preventing seizure. If the Si content is less than 0.1%, the desired lubricating performance cannot be exhibited, which is insufficient for preventing seizure on the die. On the other hand, if the Si content exceeds 0.5%, it becomes brittle and the workability deteriorates. Accordingly, the proper content of Si is preferably set to 0.1 to 0.5%.

Iron (Fe) and chromium (Cr) exert an effect of making crystals finer and preventing seizure on the die during ironing. If the Fe content is less than 0.3%, the desired effect cannot be obtained. On the other hand, if the Fe content exceeds 0.7%, it becomes brittle and the workability deteriorates. Therefore, the content of Fe is preferably set to 0.3 to 0.7%.
In addition, when Cr is added, in order to obtain a desired effect, the Cr content is set to 0.001% or more, and in order to prevent brittleness and deterioration of workability, the Cr content is set to 0.10. % Or less is preferable. Therefore, when adding Cr, the Cr content is preferably set to 0.001 to 0.10%.

  Copper (Cu) forms an intermetallic compound with Mg, and has solid solution hardening, precipitation hardening, and dispersion hardening actions. If the Cu content is less than 0.05%, these effects are poor, and if the Cu content exceeds 0.5%, the workability deteriorates. Therefore, the Cu content is preferably set to 0.05 to 0.5%.

  Manganese (Mn) forms an intermetallic compound together with Fe, Si, and Al, and serves as a crystallization phase and a dispersed phase to exhibit a dispersion hardening action, and also exhibits an effect of preventing seizure on a die during ironing processing. If the Mn content is less than 0.5%, desired curing characteristics cannot be obtained. On the other hand, if the Mn content exceeds 1.5%, it becomes brittle and the workability deteriorates. Therefore, the Mn content is preferably set to 0.5 to 1.5%.

  Magnesium (Mg) has a solid solution strengthening action, enhances work hardening at the time of rolling, and exhibits dispersion hardening and precipitation hardening by coexisting with the Si and Cu. When the Mg content is less than 0.4%, these functions and effects are not sufficiently exhibited, and when the Mg content exceeds 1.5%, the workability deteriorates, and particularly the curl workability deteriorates. Therefore, the Mg content is preferably set to 0.4 to 1.5%, preferably 1.1 to 1.3%.

Zinc (Zn) has the effect of refining the precipitated intermetallic compounds of Mg, Si, and Cu. In the case of adding Zn, in order to obtain a desired effect, the content is set to 0.05% or more, and in order to suppress deterioration of workability and corrosion resistance, the Zn content is set to 0.30% or less. Preferably there is. Accordingly, the Zn content is preferably set to 0.05 to 0.30%.
Titanium (Ti) has the effect of refining crystal grains and improving workability.
In the case of adding Ti, in order to obtain a desired effect, the content is set to 0.05% or more, and in order to suppress deterioration of workability due to the formation of a coarse compound, The amount is preferably 0.10% or less. Accordingly, the Ti content is preferably set to 0.05 to 0.10%.

  The body 11 of the DI can 10 has a tensile strength of 315 MPa or more, a 0.2% yield strength of 290 MPa or more, and a difference between these tensile strengths and 0.2% yield strength of 27.5 MPa or more, preferably 29 MPa. The above is preferable.

Table 1 below shows, as an example, two DI cans having different projecting amounts of convex portions according to the above embodiment, corresponding to the crossing angle θ with respect to the rolling direction at the center of the bottom 12 and the crossing angle θ. The relationship of the puncture strength (unit: N) in the circumferential direction position to perform is shown.
<Table 1>
Crossing angle θ 0 ° 45 ° 90 °
Example 1 42N 45N 43N
Example 2 42N 47N 43N
Comparative Example 1 42N 42N 43N
Comparative Example 2 41N 40N 43N
In Table 1 above, Example 1 is a DI can according to the above embodiment, in which the protruding amount of the convex portion is about 0.1 mm, and Example 2 is a DI can according to the above embodiment. Comparative example 1 is a DI can molded with a conventional material (projection at an angle of 45 ° with respect to the rolling direction is 0.1 mm or less). In Comparative Example 2, the body 11 having a projection amount of 0.6 mm equivalent to that of Example 2 is developed into a flat plate (the crossing angle θ indicates the circumferential position before deployment). The protrusion amounts in Examples 1 and 2 and Comparative Examples 1 and 2 are values when the contents are not filled.

  Further, the piercing strength is a presser having a radius of curvature of 0.5 mm on the outer surface at a position 60 mm away from the grounding portion in the can axis direction of the barrel portion of the DI can 10 (approximately the center position of the can in the can axis direction). Was moved at a rate of 50 mm / min toward the inside in the radial direction of the barrel portion, and the magnitude of the pressing force when a hole was formed in the barrel portion of the can was measured, and this was defined as the piercing strength.

From the above examples, it was confirmed that the DI can according to the present invention has a higher piercing strength when 0.6 mm is the protrusion amount of the convex portion within the range of 0.1 mm to 0.6 mm. .
Moreover, since the piercing strength of Examples 1 and 2 is higher than that of the conventional DI can of Example 1, the reduction in strength due to the anisotropy in the rolling direction of the plate material forming the DI can results in a final reduction rate. Was found to be 45% to 80%, and it was confirmed that the ironing rate in the drawing ironing process was improved from 51.4% to 60.4%.
Moreover, since the DI can according to the present invention has a high piercing strength at a crossing angle of 45 ° compared to the flat plate of Comparative Example 2, the DI can of Examples 1 and 2 has a decrease in strength due to material anisotropy. It was confirmed that not only the improvement but also that the position corresponding to the crossing angle of 45 ° was the convex portion contributed to the improvement of the piercing strength.

As described above, the DI can 10 according to the above embodiment is subjected to cold finish rolling with a final reduction rate of 45% to 80%, and the ironing rate when drawing and ironing the plate material is 51.4%. Since the ratio is 60.4% or less, the circumferential direction A1, A2, A3, A4 of the body portion 11 corresponding to the crossing angle of 45 ° with respect to the rolling direction of the plate material W at the center of the bottom portion 12 of the can is the circumferential direction. Is formed with a convex portion 16 projecting outward of the body portion 11 extending in the direction of the can axis with a 90 ° interval therebetween. As a result, the piercing strength is increased and pinhole characteristics are improved. The generation of holes is suppressed.
Further, it is possible to maintain the current equivalent weight of the can by suppressing an increase in the manufacturing cost of the can body.

  Further, according to the DI can 10 of the above-described embodiment, the outer diameter of the trunk portion 11 is set to 65 mm or more and 67 mm or less, the height is set to about 123.5 mm, and the thickness at the thinnest portion of the trunk portion 11 is 0.1. Since a can body having an inner capacity of 350 ml for which the inner volume is set to 105 mm or more and 0.125 mm or less is formed, without causing excessive increase in the weight of the can, insufficient height, increase in manufacturing cost, and reduction in buckling strength, The puncture strength can be improved.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. The DI can 10 was formed by drawing and squeezing a disk-shaped plate material W having an outer diameter of 0.24 mm or more and 0.28 mm or less and an outer diameter of 145 mm or more and 155 mm or less. It is also possible to form DI cans 10 having different thicknesses, outer diameters, and capacities by setting them in the range of 4% or more and 60.4% or less.

Moreover, although the plate | plate material W was formed as final plate | board thickness by performing cold finish rolling of 45%-80% of final rolling reduction, it is not restricted to the manufacturing method by the said cold finish rolling.
Moreover, it is also possible to perform inner surface coating and outer surface coating other than those described in the above embodiment.

  In the above embodiment, the DI can has a flange that winds up the can lid at the opening end. However, the DI can is necked at the opening and the shoulder and the cap are screwed together. It is also possible to use it for a bottle can having a cap portion that is made possible.

  It is possible to provide a DI can that can prevent the occurrence of pinholes.

It is process drawing which shows the manufacturing method of DI can shown as one Embodiment of this invention. It is a longitudinal cross-sectional view of DI can shown in FIG. It is a cross-sectional view when the can body of the DI can shown in FIG. 1 is seen from the can axis direction. It is a figure for demonstrating the final rolling reduction in one Embodiment of this invention.

Explanation of symbols

10 DI Can 11 Body 12 Bottom 16 Convex Part D1, D2, D3, D4 Radial Distance (Convex Part)
Dmin Radial distance (minimum value of parts other than the convex part)
O Center axis W Plate material

Claims (4)

A bottomed cylindrical DI can formed by squeezing and ironing a plate of aluminum alloy,
The plate, the final reduction ratio after the intermediate annealing is 45% to 80% Rutotomoni plate thickness is less than 0.28mm or 0.24 mm,
In the drawing ironing process, the ironing rate is 51.4% to 56.3%,
The cross-sectional shape perpendicular to the central axis O of the trunk part includes a convex part protruding outward with a 90 ° interval in the circumferential direction of the trunk part,
The DI can characterized in that the circumferential position of the convex portion in the body portion is formed such that the crossing angle with respect to the rolling direction of the plate material at the center of the bottom portion is 45 °. The DI can according to claim 1,
The radial distance of the convex portion from the central axis O formed in the can axis direction through the bottom is
A DI can characterized in that the DI can is formed larger in a range of 0.1 mm or more and 0.6 mm or less than a radial distance of a portion other than the convex portion. The DI can according to claim 1 or claim 2,
The radial distance of the convex portion from the central axis O in the state filled with the contents is:
A DI can characterized in that the DI can is formed larger than a radial distance of a portion other than the convex portion within a range of 0.05 mm or more and 0.15 mm or less. The DI can according to any one of claims 1 to 3,
The said aluminum alloy is mass: Si: 0.1-0.5%, Fe: 0.3-0.7%, Cu: 0.05-0.5%, Mn: 0.5-1. 5%, Mg: 0.4-1.5%, Cr: 0.001-0.10%, Zn: 0.05-0.30%, Ti: 0.05-0.10%, A DI can characterized in that the balance is Al containing inevitable impurities.

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