JP2008057030A - Di can - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a DI can which prevents a pinhole from forming therein without increasing a manufacturing cost. <P>SOLUTION: An aluminum alloy comprises, by mass%, 0.1 to 0.5% Si, 0.3 to 0.7% Fe, 0.05 to 0.5% Cu, 0.5 to 1.5% Mn, 0.4 to 2.0% Mg, 0 to 0.1% Cr, 0 to 0.5% Zn, 0 to 0.15% Ti and the balance aluminum with unavoidable impurities. The cylindrical DI can 10 with the bottom is formed by drawing and ironing a sheet made from the aluminum alloy so that the sack body has a thickness of 0.105 mm or more but 0.125 mm or less in the thinnest part, and has such a difference between a tensile strength and a 0.2% yield strength as to be controlled to 27.5 MPa or higher. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

  This type of can body is used for cans with a can lid wrapped around the open end or bottle cans with a cap screwed to the open end, filled with contents such as beverages, sealed, and marketed. It is 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). The body portion has a thickness of about 0.106 mm at the thinnest portion, and a difference between the tensile strength and the 0.2% proof stress is 27 MPa or less.

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, the conventional can body requires a device for laminating a resin film on a plate material, and a dedicated device for drawing and ironing the plate material on which the resin film is disposed. There was a problem that the increase could not be avoided.

  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 such problems and achieve the above-mentioned object, the DI can of the present invention is composed of Si: 0.1 to 0.5%, Fe: 0.3 to 0.7%, Cu : 0.05 to 0.5%, Mn: 0.5 to 1.5%, Mg: 0.4 to 2.0%, Cr: 0 to 0.1%, Zn: 0 to 0.5%, Ti: A bottomed cylindrical DI can formed by squeezing and squeezing an aluminum alloy plate made of aluminum containing 0 to 0.15% and the balance containing unavoidable impurities. The thickness of the thinnest part is 0.105 mm or more and 0.125 mm or less, and the difference between the tensile strength and the 0.2% proof stress is 27.5 MPa or more.
Further, the aluminum alloy has a mass% of Mg: 0.4 to 1.5%, Cr: 0.001 to 0.10%, Zn: 0.05 to 0.30%, Ti: 0.05 to More preferably, the content is 0.10%.

According to the present invention, since the difference between the tensile strength and the 0.2% proof stress in the barrel portion of the DI can is 27.5 MPa or more, the barrel thickness is maintained at the same level as the current barrel. It is possible to increase the stress value required until the portion is plastically deformed and then ruptured. As a result, the amount of strain under plastic deformation can be increased. That is, it is possible to increase the amount of strain until the processing limit is reached in the body portion. Therefore, for example, in the process where a sharp body collides with the body and this sharp body presses the body toward the inside, it is possible to work harden while denting the inside of the body without breaking this part. Thus, the piercing strength can be improved.
As described above, the current manufacturing equipment can be used as it is, and the weight of the can can be maintained at the same level as the current one, and the occurrence of pinholes can be prevented without increasing the manufacturing cost.

  Here, the DI can may be formed by drawing and ironing a plate material having a thickness of 0.24 mm or more and 0.28 mm or less at an ironing rate of 51.4% or more and 60.4% or less.

  In this case, since the thickness of the plate material is 0.24 mm or more, it becomes possible to provide a sufficient buckling strength at the bottom of the DI can, and since the thickness is 0.28 mm or less, the ironing rate is reduced. Even when the thickness is 51.4% or more and 60.4% or less, which is smaller than the conventional one, it is possible to prevent the body thickness from becoming excessively large.

  In general, when drawing a thin plate material, if the ironing ratio is small, the height of the DI can, that is, the size in the can axis direction may be insufficient. By making the diameter larger than before, the height of the DI can can be maintained at the current level. For example, the outer diameter of the body portion is 65 mm or more and 67 mm or less, the height is about 123.5 mm, and the inner volume of the thinnest portion of the body portion is 0.105 mm or more and 0.125 mm or less is 350 ml. When forming a DI can for forming a can for the above, if the outer diameter of the disk-shaped plate material is 145 mm or more and 155 mm or less and the thickness is 0.24 mm or more and 0.28 mm or less, the ironing rate is Even if it is made as small as 51.4% or more and 60.4% or less, the height of the DI can is not insufficient.

  Further, for example, the outer diameter of the body portion is set to 65 mm or more and 67 mm or less, the height is set to about 168 mm, and the inner volume of the thinnest portion of the body portion is set to 0.105 mm or more and 0.125 mm or less to be 500 ml. In the case of forming a DI can for forming a can body, the outer diameter of the disk-shaped plate material is 160 mm or more and 180 mm or less, and the thickness is 0.24 mm or more and 0.28 mm or less. The ironing rate can be 51.4% or more and 60.4% or less.

In addition, the plate material is subjected to hot rolling, cold rolling and annealing on the ingot to form an intermediate plate material having a predetermined plate thickness, and then the intermediate plate material is subjected to cold finish rolling with a final reduction ratio of 45% to 80%. May be formed to a final thickness.
Here, as shown in the flow chart of FIG. 3, 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. 3 (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. 3B, 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. 3B may be performed a plurality of times, for example, 4 to 5 times, but it does not depend on the number of times.

In this case, pinholes can be reliably prevented from occurring.
That is, the processing by cold finish rolling with a final reduction ratio of 80% or less is a processing degree lower than the processing limit, and the plate material thus formed is subjected to drawing ironing (hereinafter referred to as “DI processing”). Does not exceed the processing limit. Therefore, among the effects described above, it is possible to reliably realize an increase in the amount of strain until the processing limit is reached in the body portion.
Further, by applying DI processing to a plate material formed by cold finish rolling with a final reduction ratio of 45% or more, sufficient strength can be obtained by work hardening in DI processing.
Therefore, for example, when the sharp body collides with the trunk portion, it is possible to prevent the trunk portion from breaking immediately.

  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 and FIG. 2 show a DI can and a method for manufacturing a DI can shown as an embodiment of the present invention. FIG. 2 shows a DI can formed up to a neck portion and a flange portion.

First, the manufacturing method of a board | plate material is demonstrated.
This sheet material W is subjected to hot rolling, cold rolling and annealing on an ingot of Al alloy such as JIS3004 (AA3004) or JIS3104 (AA3104) to form an intermediate sheet material having a predetermined sheet thickness, It is formed to a final thickness (0.24 mm or more and 0.28 mm or less) by performing cold finish rolling with a final reduction ratio of 45% to 80%.
First, the plate material W is punched to form a disk-shaped plate material (blank) 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.
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, polyester paint is used to print and paint the outer surface of the body of the DI can, and the DI can that has been externally printed and coated is heated at 180 ° C for 30 seconds or longer. The inner surface coating is performed by coating the inner surface of the DI can whose outer surface is coated with, for example, an epoxy-based paint and heating it at 200 ° C. for 60 seconds or more.

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 42 mm. The outer diameter is about 90 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.

The DI can 10 has a size in the can axis direction, that is, a height of about 123.5 mm and an outer diameter of 65 mm or more and 67 mm or less.
Further, as shown in FIG. 2, the bottom portion 12 includes a dome portion 12 a that is recessed toward the inside in the can axis direction of the trunk portion 11, and an outer peripheral edge portion of the dome portion 12 a is in the can axis direction of the trunk portion 11. It is set as the annular convex part 12c which protrudes toward the outer side. 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. .

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.

  In the plate material W, Si: 0.1 to 0.5%, Fe: 0.3 to 0.7%, Cu: 0.05 to 0.5%, Mn: 0.00% by weight (hereinafter the same). 5-1.5%, Mg: 0.4-1.5%, Cr: 0.001-0.10%, Zn: 0.05-0.30%, Ti: 0.05-0.10% In which the balance is made of Al containing inevitable impurities. The reason will be described below.

  Silicon (Si) forms a compound with Mg contained at the same time, and acts as a solid solution hardening, precipitation hardening, and dispersion hardening, and also 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. Therefore, the appropriate content of Si is 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 proper content of Fe is 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 content of Cr is 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 appropriate content of Cu is 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 appropriate content of Mn is 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 appropriate content of Mg is 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. Therefore, the proper content of Zn is 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. Therefore, the proper content of Ti is 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% proof stress of 290 MPa or more, and a difference between these tensile strengths and 0.2% proof stress of 27.5 MPa or more, preferably 29 MPa or more.

  As described above, according to the DI can 10 according to the present embodiment, the difference between the tensile strength and the 0.2% proof stress in the body portion 11 is 27.5 MPa or more. While maintaining the same level as the present, it is possible to increase the stress value required until the body 11 is plastically deformed and then broken, and as a result, the amount of strain under plastic deformation can be increased. That is, it becomes possible to increase the amount of strain until the processing limit is reached in the body portion 11.

Therefore, for example, in the process in which the sharp body collides with the body portion 11 and the sharp body presses the body portion 11 toward the inside, the portion is not hardened and is hardened while being recessed toward the inside of the body portion 11. And the puncture strength can be improved.
As described above, the current manufacturing equipment can be used as it is without replacement or readjustment of parts, and the weight of the can can be maintained at the same level as that of the present, generating pinholes without increasing manufacturing costs. Can be prevented.

  Further, since the plate material W has a thickness of 0.24 mm or more, the bottom portion 12 of the DI can 10 can be provided with sufficient buckling strength. In addition, since the thickness is 0.28 mm or less, even if the ironing rate is 51.4% or more and 60.4% or less, which is smaller than the conventional one, it is possible to prevent the thickness of the body portion 11 from becoming excessively large. Thus, it is possible to reliably realize the suppression of the increase in the manufacturing cost of the can body as described above and the maintenance of the can weight at the same level as the current one.

  Here, when the sheet material W having a thickness of 0.24 mm or more and 0.28 mm or less is drawn and ironed (hereinafter referred to as “DI processing”), the ironing rate is 51.4% or more and 60.4% or less and the ironing rate is small. There is a possibility that the height of the DI can 10, that is, the size in the can axis direction may be insufficient, but in this embodiment, the outer diameter of the plate material W is set to 145 mm or more and 155 mm or less, which is larger than the conventional one. The height can be maintained at the current level.

  As described above, in the DI can manufacturing method of the present 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. To increase the can weight excessively, to cause insufficient height, and to increase the manufacturing cost of the DI can for forming a can for 350 ml having an inner volume of 350 mm or more and 0.125 mm or less. It can be formed with improved puncture strength without causing problems such as lowering buckling strength.

  Furthermore, after the plate material W is rolled and annealed on the ingot to form an intermediate plate material having a predetermined thickness, the intermediate plate material is subjected to cold finish rolling with a final reduction ratio of 45% to 80%. Since it is formed to have a plate thickness, it is possible to reliably prevent pin holes from occurring in the DI can 10.

That is, the processing by cold finish rolling with a final reduction ratio of 80% or less is set to a processing degree lower than the processing limit, and the processing limit is not exceeded even if DI processing is performed on the plate material W thus formed. Therefore, it is possible to reliably realize an increase in the amount of strain until the processing limit is reached in the body portion 11 among the effects described above.
Further, by applying DI processing to the plate material W formed by cold finish rolling with a final reduction ratio of 45% or more, sufficient strength can be obtained by work hardening in DI processing. Therefore, for example, when the sharp body collides with the body part 11, it is possible to prevent the body part 11 from being broken immediately.

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.
For example, in the above-described embodiment, the disc-shaped plate material W having a thickness 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 is squeezed with an ironing ratio of 51.4% or more and 60.4% or less. Although the DI can 10 is formed by processing, the DI can 10 may be formed by changing the thickness, outer diameter, and ironing rate. 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 such a manufacturing method.

Here, among the effects explained above, by setting the ironing rate within the above range, it is possible to prevent the occurrence of pinholes without increasing the weight of the can while maintaining the thickness of the body 11 equal to the current thickness. A first verification test was conducted on what could be done.
In the first verification test, an Al alloy plate material having an after baking yield strength of 275 MPa to 284 MPa was subjected to DI processing. Here, the after-baking yield strength is a method for evaluating an Al alloy material, and is a yield strength obtained by a tensile test after heating an Al alloy plate material at 210 ° C. for 10 minutes (the same applies hereinafter).
In this verification experiment, the piercing strength was measured by printing and painting the outer surface of the body of the DI can, including the printed portion of character information, using a polyester-based paint. By forming a 50 mg / dm ² coating film by heating the DI can at 180 ° C. for 30 seconds, coating the inner surface of the DI can with an epoxy paint and heating at 200 ° C. for 60 seconds A DI can on which outer surface printing, outer surface coating, and inner surface coating with a 40 mg / dm ² coating film were formed was filled with carbonated water and the can lid was wound, and the internal pressure of the can was adjusted to 0.2 at room temperature of 20 ° C. A DI can of 245 MPa was used.
For measurement, a presser with a radius of curvature of 2.25 mm was placed on the outer surface at a position 60 mm above the grounding portion in the can axis direction of the DI can body (approximately the center position of the can in the can axis direction). It was moved at a rate of 25 mm / min toward the inside of the body in the radial direction, the magnitude of the pressing force when a hole was formed in the body of the can was measured, and this was defined as the piercing strength.

The results are shown in FIG.
From this result, the sheet material made of the above Al alloy was subjected to squeezing and ironing at an ironing rate of 51.4% or more and 60.4% or less, and the thickness of the thinnest portion of the body portion 11 was 0.105 mm or more and 0.125 mm or less. In the DI can 10, the weight is 11 g to 12 g and the bulge strength is maintained at 0.5 MPa or more, and the piercing strength is increased to 124 N or more, that is, it is possible to prevent the occurrence of pinholes. It was confirmed that

Here, the 2nd verification test about the effect demonstrated above was implemented. In carrying out this test, six types of DI cans of Examples 1 to 5 and Comparative Examples 1 and 2 were prepared.
In the second verification test, an Al alloy having an after baking yield strength of 275 MPa to 284 MPa was used in both the examples and the comparative examples.
In the examples, an Al alloy of Si: 0.30%, Fe: 0.43%, Cu: 0.27%, Mn: 1.00%, Mg: 1.25%, Zn: 0.10% is used. did. The molten alloy was degassed and inclusions removed by a conventional method, and cast into a slab having a thickness of 550 mm, a width of 1.5 m, and a length of 4.5 m by semi-continuous casting. Subsequently, the slab was subjected to a soaking treatment, followed by hot rolling until the thickness reached 6.5 mm, and then cold rolling. 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%. The plate material (product coil) of Example 1 having a final plate thickness of 0.27 mm was obtained. The homogenization treatment was performed at 600 ° C. for 6 hours.

  Next, this plate material is punched out to obtain a circular plate material W having a diameter of about 150 mm. The plate material W has a squeezing rate of 60.4% and the thickness at the thinnest portion of the body 11 becomes 0.105 mm. The DI can of Example 1 was formed by squeezing and squeezing up to.

In Examples 2, 3, and 5, a plate material W having a diameter of about 150 mm is obtained by punching out a plate material formed in the same manner as the plate material of Example 1 except that the final rolling reduction is 80%. The plate material W was drawn and ironed to form a DI can. In Example 2, a DI can was formed by squeezing and squeezing until the thickness of the thinnest portion of the body portion 11 was 0.110 mm with an ironing rate of 58.5%. In Example 3, a DI can was formed by squeezing and squeezing until the thickness of the thinnest portion of the body portion 11 was 0.115 mm with an ironing rate of 57.4%. In Example 5, a DI can was formed by performing squeezing and squeezing until the thickness of the thinnest portion of the body portion 11 was 0.125 mm with an squeezing rate of 51.4%.
Further, in Example 4, except that the final rolling reduction is 78%, a plate material formed in the same manner as the plate material of Example 1 is punched out to obtain a circular plate material W having a diameter of about 150 mm. A DI can was formed by subjecting the plate material W to a squeezing rate of 55.0% and a squeezing and squeezing process until the thickness of the thinnest portion of the body 11 was 0.120 mm.

  In the comparative example, an Al alloy of Si: 0.27%, Fe: 0.43%, Cu: 0.23%, Mn: 1.05%, Mg: 1.00%, Zn: 0.19% is used. did. The molten alloy was degassed and inclusions removed by a conventional method, and cast into a slab having a thickness of 550 mm, a width of 1.5 m, and a length of 4.5 m by semi-continuous casting. Subsequently, after the slab was subjected to a soaking treatment, hot rough rolling was performed until the thickness became 25 mm, and then hot finish rolling was performed to a thickness of 2.0 mm. And after making it self-annealed, it cold-rolled with the final reduction of 85%, it was set as final plate thickness 0.296mm, and also stabilized annealing was performed, and the board | plate material of the comparative example 1 was obtained.

  Next, this plate material is punched out to obtain a circular plate material W. The plate material W is subjected to squeezing and squeezing until the thickness of the thinnest portion of the body portion 11 is 0.111 mm at a squeezing rate of 62.5%. The DI can of Comparative Example 1 was formed.

  In Comparative Example 2, a plate material W having a thickness of 0.296 mm formed by punching out a plate material having a thickness of 0.296 mm, which was formed in the same manner as the plate material of Comparative Example 1, except that the final reduction ratio was 90%, was obtained. The DI can of Comparative Example 2 was formed by drawing and ironing until the thickness at the thinnest portion of the body portion 11 was 0.111 mm at an ironing rate of 62.5%.

Then, a verification test was performed, and the tensile strength TS, 0.2% proof stress YS, elongation rate, and piercing strength in the body of the DI cans of Examples 1 to 5 and Comparative Examples 1 and 2 were measured.
For the measurement of the tensile strength TS and 0.2% proof stress YS of this verification test, as shown in FIG. 6, the rolling direction in the body 11 of the DI can 10 intersects the can axis direction in the body 11 at 45 °. A test piece cut in the can axis direction at the circumferential position of the DI can 10 was used.
In this verification experiment, the plate thickness of the plate used in Examples 1 and 2 was 0.265 mm, the plate thickness of the plate used in Example 3 was 0.270 mm, and the plate thickness of the plate used in Example 4 was 0.267 mm. The plate thickness used in Example 5 was 0.257 mm, and the piercing strength was measured under the same conditions as described above.

  As a result, as shown in FIG. 5, in Examples 1 to 5, in comparison with Comparative Examples 1 and 2, the thickness of the trunk portion 11 was maintained to be equal to 0.105 mm or more and 0.125 mm or less. By improving YS to 27.5 MPa or more, it was confirmed that the puncture strength was improved to 126 N or more, and the occurrence of pinholes could be effectively prevented.

  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 partially expanded longitudinal cross-sectional view of the DI can shown in FIG. It is a figure for demonstrating the final rolling reduction in one Embodiment of this invention. It is a figure which shows the result of the 1st verification test which verified the effect of the DI can obtained by the manufacturing method of DI can shown as one Embodiment of this invention. It is a figure which shows the result of the 2nd verification test which verified the effect of the DI can shown as one Embodiment of this invention. It is a figure explaining the sampling position in the DI can of the test piece used in order to measure tensile strength TS and 0.2% yield strength YS in the verification test which concerns on this invention.

Explanation of symbols

10 DI can 11 Body W Plate material

Claims (3)

Mass% is Si: 0.1 to 0.5%, Fe: 0.3 to 0.7%, Cu: 0.05 to 0.5%, Mn: 0.5 to 1.5%, Mg: 0 .4 to 2.0%, Cr: 0 to 0.1%, Zn: 0 to 0.5%, Ti: 0 to 0.15%, the balance of aluminum alloy made of aluminum containing inevitable impurities A bottomed cylindrical DI can formed by squeezing and squeezing a plate material,
The body is characterized in that the thickness of the thinnest part is 0.105 mm or more and 0.125 mm or less, and the difference between the tensile strength and the 0.2% proof stress is 27.5 MPa or more. DI can. The DI can according to claim 1,
The aluminum alloy has a mass% of Mg: 0.4 to 1.5%, Cr: 0.001 to 0.10%, Zn: 0.05 to 0.30%, Ti: 0.05 to 0.00. DI can characterized by 10%. The DI can according to claim 1 or claim 2,
A DI can characterized in that the thickness of the thickest part of the bottom of the can is 0.24 mm or more and 0.28 mm or less.

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