JP5111807B2 - DI can manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing 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. Conventionally, DI cans used for such cans are obtained by subjecting a plate material made of an Al alloy such as JIS3004 (AA3004) or JIS3104 (AA3104) to a drawing rate of 63.7% (Drawing & Ironing). The thickness at the thinnest part of the body part is 0.106 mm.

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 the occurrence of pinholes. In this case, parts may need to be replaced or readjusted for various manufacturing equipment, and the weight of the can also increases, which also increases the manufacturing cost. I can't avoid doing it.

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 method of manufacturing 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 object, the DI can manufacturing method of the present invention has a mass% of Si: 0.1 to 0.5%, Fe: 0.3 to 0.7. %, Cu: 0.05-0.5%, Mn: 0.5-1.5%, Mg: 0.4-2.0%, Cr: 0-0.1%, Zn: 0-0. A DI can that forms a bottomed cylindrical DI can by drawing and ironing an aluminum alloy plate made of aluminum containing 5%, Ti: 0 to 0.15% and the balance containing inevitable impurities. 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 final reduction ratio of 45% to 80% is applied to the intermediate plate material. The aluminum sheet is formed to a final sheet thickness by performing cold finish rolling of 51.4% to 59.4%. The aluminum alloy plate is subjected to drawing and ironing so that the thickness of the thinnest part of the body is 0.105 mm or more and 0.110 mm or less .
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 ironing rate is smaller than the conventional one, it is possible to improve the breaking strain and breaking strength of the trunk while maintaining the same thickness as the current thickness. It is possible to increase the stress value required until the body portion is plastically deformed and then ruptured. As a result, the strain amount (residual deformation amount) under the plastic deformation can be increased. In other words, it is possible to leave a deformation amount that can be plastically deformed and hardened without breaking in the body portion. For example, even when the sharp body collides with the body portion, the body portion is not broken. Can be hardened while being recessed toward the inside.
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, 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, it is possible to reliably prevent pin holes from occurring in the DI can. 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 exceeded even if DI processing (Drawing & Ironing) is applied to the plate material thus formed. There is nothing.
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.
As described above, it is possible to form a DI can having both breaking strain and breaking strength improved, and pinholes can be prevented from occurring in the obtained DI can.

  In general, when drawing and squeezing a thin plate material, if the squeeze rate is small, the height of the DI can, that is, the size in the can axis direction may be insufficient. By making the outer 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, the outer diameter of the disk-shaped plate member is 145 mm or more and 155 mm or less, the thickness is 0.24 mm or more and 0.28 mm or less, and the ironing rate is 51.4. If the percentage is from 6% to 60.4%, the height of the DI can will not be 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.

Further, the neck portion and flange portion of the DI can may be formed by spin flow necking.
When the neck and flange of the DI can are formed by spin flow necking, the side wall near the opening end of the DI can is sandwiched and formed from the outside and inside, so that work hardening during necking is difficult to occur. Even when the moldability of the material is low, necking can be easily performed while suppressing the occurrence of wrinkles or the like in the molded portion.
As a result, a more stable necking process can be performed on a material whose DI moldability and neck moldability are reduced in order to improve the pressure strength and pinhole characteristics.

  According to the DI can manufacturing method of the present invention, it is possible to 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.

Next, the DI body processing device performs redrawing and ironing on the cup-shaped body W1 to form a bottomed cylindrical body W2.
A DI processing apparatus used for redrawing and ironing includes a single redrawing die having a circular through hole for redrawing and a plurality of circular through holes arranged coaxially with the redrawing die. One (for example, three) ironing dies (coiling dies), coaxial with the ironing dies, and can be fitted inside the through holes of the ironing dies, and can be moved in the axial direction. A cylindrical punch sleeve, and a cylindrical cup holder sleeve fitted to the outside of the punch sleeve.

  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 mass% (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, 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. 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 0.4 to 0.8%.

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%.

  Further, 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 14 connected from the opening end of the neck portion 13 can be formed by spin flow necking. A case where the neck portion 13 and the flange portion 14 are formed by spin flow necking will be described.

  As shown in FIGS. 4 and 5, the spin flow necking apparatus used for the spin flow necking process has a base pad 22 that adsorbs and supports the bottom portion 12 of the DI can 10 in which a pre-neck is preliminarily formed around the opening end portion 11a by die necking. And a slide roll 23 fitted around the open end 11a of the DI can 10 while the DI can 10 is rotated around its axis by the base pad 22 and inserted into the DI can 10 with a smaller diameter than the slide roll 23. Between the inner roll 24 and the forming roll 25. The inner roll 24 is arranged outside and the forming roll (outer roll) 25 disposed outside the can and reciprocally movable in the substantially radial direction of the DI can 10. The diameter of the DI can 10 is reduced toward the opening end portion 11a, and the neck portion 13 reduced in diameter from the body portion 11 is provided on the DI can 10. It is intended to form.

  That is, the inner roll 24 inserted into the DI can 10 is offset with respect to the axis of the DI can 10 and brought into contact with the inner surface of the DI can 10 and between the forming roll 25 brought into contact with the outer surface of the DI can 10. Reduce the diameter while sandwiching the can. Here, the slide roll 23 and the forming roll 25 are arranged so as to be movable in the axial direction thereof, and are always urged toward the direction of the internal roll 24 (forward movement direction) by the springs 26 and 27.

  In addition, these inner roll 24 and molding roll 25 are usually carried out while each DI can 10 is conveyed at a high speed, and its operation is uniformly defined by a cam (not shown). Each outer peripheral surface can be regularly contacted and separated from the inner and outer surfaces of the DI can 10.

  A cam ring 28 is fixed to the slide roll 23 in the vicinity of the outer side in the radial direction and abuts the tip 28a on the outer peripheral surface of the forming roll 25. As shown in FIG. An interval t between the slide roll 23 and the forming roll 25 is defined.

  On the other hand, the outer peripheral surface of the forming roll 25 is composed of a curved surface 25a near the center in the axial direction, an inner roll side forming surface 25b on the inner roll 24 side, and a slide side forming surface 25c on the slide roll 23 side. .

  The step surface 25e is disposed at a portion facing the tip portion 28a of the cam ring 28 at the end of the necking process, and is formed with a predetermined step D with respect to the main molding surface 25d. Further, the position of the front end portion 28a of the cam ring 28 is set so that the interval t is larger than the thickness of the DI can 10 by a predetermined amount in contact with the main molding surface 25d.

  Hereinafter, the necking can manufacturing method by spin flow necking using the necking can manufacturing apparatus 20 of this embodiment is divided into [neck portion diameter reducing step] and [opening end portion forming step], and refer to FIG. I will explain.

  [Neck part diameter reducing step] In the spin flow necking process, as in the prior art, first, as shown in FIG. 5A, the slide roll 23 and the internal roll 24 which are brought close to the opening end 11a peripheral side of the DI can 10 are used. Is placed in the DI can 10, the forming roll 25 is brought close to the outside of the DI can 10, and the wall surface of the DI can 10 is sandwiched in the radial direction as shown in FIG. Displace toward 10 inward in the radial direction.

  When the forming roll 25 comes into contact with the DI can 10, the forming roll 25 receives a force in a direction of retreating along the tapered surface of the internal roll 24, and is retreated against the biasing force of the spring 27, thereby forming the roll 25. While moving inward in the radial direction of the DI can, the diameter of the periphery of the open end 11a is reduced. As the diameter reduction process proceeds, the slide roll 23 is also displaced in the direction of being pushed back by the forming roll 25 as shown in FIG.

  As a result, the interval between the inner roll 24 and the slide roll 23 is gradually widened, and the diameter reduction processing around the opening end 11a of the DI can 10 is performed so that the molding roll 25 is inserted therebetween. become.

  At this time, the interval t between the slide roll 23 and the forming roll 25 is such that the tip portion 28a of the cam ring 28 is brought into contact with the main forming surface 25d of the forming roll 25 to reduce the diameter and increase the thickness of the neck portion 13. The neck portion 13 is formed in a reduced diameter by moving smoothly between the slide roll 23 and the forming roll 25 while having a predetermined clearance with respect to the thickness.

  Thereafter, as shown in FIG. 5 (d), the inner roll 24 is returned to a position that is concentric with the axis of the DI can 10, and the forming roll 25 is separated from the outer surface of the DI can 10. Then, as shown in FIG. 5E, the slide roll 23 and the internal roll 24 are extracted from the DI can 10 and the spin flow necking process is completed.

As described above, according to the manufacturing method of the DI can 10 according to the present embodiment, the ironing rate is made smaller than that of the conventional case, so that the thickness of the barrel portion 11 is maintained at the same level as that of the current barrel portion 11. It is possible to improve the breaking strain and breaking strength, and it is possible to increase the amount of residual deformation that can be plastically deformed without breaking in the body portion 11. In other words, it is possible to leave a deformation amount that can be plastically deformed and hardened without breaking in the body portion 11. For example, even when a sharp body collides with the body portion 11, the body portion is not broken without being broken. Work hardening can be performed while being recessed toward the inside of the portion 11.
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, and since the thickness is 0.28 mm or less, the ironing is performed. Even if the rate is made smaller than before, it becomes possible to prevent the thickness of the body 11 from becoming excessively large, and by using the current manufacturing apparatus as it is without replacement or readjustment of parts, An increase in manufacturing cost can be suppressed, and the weight of the can can be maintained 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, if the ironing ratio is small and 51.4% or more and 60.4% or less, the height of the DI can 10, that is, the can Although the size in the axial direction may be insufficient, 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, so that the height of the DI can 10 can be maintained at the current level. Therefore, in the DI can manufacturing method of the present embodiment, 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 thickness of the thinnest portion of the body portion 11 is 0.105 mm. It is possible to form a DI can for forming a can for 350 ml whose inner volume is set to 0.125 mm or less without causing a height shortage.

  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, 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 thus formed. 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.
As described above, it is possible to form a DI can having both breaking strain and breaking strength improved, and pinholes can be prevented from occurring in the obtained DI can.

  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.

  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. Two types of verification tests were conducted on what can be done.

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 result of the first verification test is shown in FIG.
From this result, the sheet material made of the 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 11 was 0.105 mm or more and 0.125 mm or less. In the DI can 10, the weight can be increased from 11g to 12g and the bulge strength to 0.5MPa or more, while maintaining the current equivalent, and the piercing strength can be increased to 124N or more, that is, pinholes can be prevented. It was confirmed that

  Next, it is possible to reliably prevent occurrence of pinholes in the DI can 10 by forming the plate material W having the final plate thickness by subjecting the intermediate plate material to cold finish rolling with a final reduction ratio of 45% to 80%. The second verification test was conducted.

  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 for 20 second in the temperature range of a heating rate of 100 degree-C / sec and 530-550 degreeC, and it anneals on the conditions of a cooling rate of 100 degree-C / sec, and then performs cold finish rolling at the final reduction of 80% As a result, a plate material (product coil) having a final plate thickness of 0.27 mm was obtained. The homogenization treatment was performed at 600 ° C. for 6 hours.

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. Then, after the slab was soaked, hot rough rolling was performed until the thickness reached 25 mm, and then hot finish rolling was performed to obtain a thickness of 1.973 mm. And after making it self-annealed, it cold-rolled with the final reduction of 85%, the final board thickness was 0.296 mm, and also stabilized annealing was performed, and the board | plate material of the comparative example 1 was obtained.
Further, the plate material of Comparative Example 2 was formed in the same manner as the plate material of Comparative Example 1 except that the thickness of the plate after hot finish rolling was 2.96 mm and the final reduction ratio was 90%.
Similarly to the plate material of Comparative Example 1, the plate material of Comparative Example 3 was formed with the thickness of the plate after hot finish rolling being 1.73 mm and the final reduction ratio being 85%.

  Next, the plate material of the example was punched out to obtain a circular plate material W having a diameter of about 150 mm, and the thickness of the thinnest portion of the body portion 11 was 0.115 mm with an ironing rate of 57.4%. The DI can of the example was formed by squeezing and ironing until it became.

  And the breaking strength in the trunk | drum of the DI can of an Example and elongation rate were measured. As a result, as shown in FIG. 7, the breaking strength was 324 MPa, and the elongation was 4.7%. The puncture strength was 152N.

The plate material of Comparative Example 1 was punched out to obtain a disk plate material, and this plate material was drawn and ironed at a squeezing rate of 62.5% to form a DI can of Comparative Example 1.
Further, the plate material of Comparative Example 2 was punched out to obtain a disk plate material, and this plate material was subjected to squeezing and ironing at a squeezing rate of 62.5% to form a DI can of Comparative Example 2.
Further, the plate material of Comparative Example 3 was punched out to obtain a disk plate material, and this plate material was subjected to squeezing and ironing at a rate of 57.0% to form a DI can of Comparative Example 3.

  And the breaking strength and elongation rate in the trunk | drum of these DI cans were measured. As a result, as shown in FIG. 7, in Comparative Example 1, the breaking strength was 319 MPa and the elongation was 2.8%, and in Comparative Example 2, the breaking strength was 314 MPa and the elongation was 2.6%. In Example 3, the breaking strength was 322 MPa, and the elongation was 3.0%. Further, the piercing strength of Comparative Example 1 was 124N, the piercing strength of Comparative Example 2 was 119N, and the piercing strength of Comparative Example 3 was 122N.

From the above, it was confirmed that in the examples, the breaking strength and the elongation rate, as well as the piercing strength, were improved as compared with Comparative Examples 1 and 2, and the occurrence of pinholes could be effectively prevented.
Further, when the example and the comparative example 3 are compared, even if the ironing rate of the example is 57.4% and the ironing rate of the comparative example 3 is 57.0%, the final reduction is achieved. It was confirmed that the example in which the rate was 80% had higher piercing strength than Comparative Example 3 having a final reduction rate of 85%.

  It is possible to provide a DI can that can prevent a pinhole from occurring in the can body.

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 spin flow necking apparatus used for the spin flow necking process which concerns on one Embodiment of this invention. It is a figure which shows the spin flow necking process which concerns on one Embodiment of this invention. It is a figure which shows the result of the 1st verification test which verified the 1st effect of the DI can obtained by the manufacturing method of the 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 obtained by the manufacturing method of DI can shown as one Embodiment of this invention.

Explanation of symbols

10 DI Can 11 Body 12 Bottom 12b Grounding Part 13 Neck Part 14 Flange Part W Plate Material

Claims (3)

Mass% is Si: 0.1-0.5%, Fe: 0.3-0.7%, Cu: 0.05-0.5%, Mn: 0.5-1.5%, Mg: Aluminum alloy composed of aluminum containing 0.4 to 2.0%, Cr: 0 to 0.1%, Zn: 0 to 0.5%, Ti: 0 to 0.15% and the balance containing inevitable impurities A method of manufacturing a DI can that is subjected to drawing and ironing on the plate material to form a bottomed cylindrical DI can,
The plate material is subjected to hot rolling, cold rolling and annealing on the ingot to form an intermediate plate material having a predetermined thickness, and then subjected to cold finish rolling with a final reduction ratio of 45% to 80%. Is formed to the final thickness,
The DI in which the aluminum alloy plate is subjected to drawing and ironing at an ironing rate of 51.4% or more and 59.4% or less, and the thickness of the thinnest part of the body is 0.105 mm or more and 0.110 mm or less. A method for producing a DI can, comprising molding a can. In the manufacturing method of DI can of 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. A method for producing a DI can, characterized by 10%. In the manufacturing method of DI can of Claim 1 or Claim 2 ,
The DI can has a neck portion and a flange portion formed by a spin flow necking process.

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