TWI582241B - Aluminum alloy plate for cans - Google Patents

Description

Aluminum alloy plate for can body

The present invention relates to an aluminum alloy sheet for a can body used for forming a two-piece can for DI (draw & ironing).

In order to achieve a reduction in environmental load and a reduction in cost, the thinning of the material for aluminum cans for beverages is progressing, and the thinning of the walls of the cans after DI forming is also progressing (previous technology) The thickness of the tank wall is about 105 to 110 μm, and the thickness of the tank wall is about 95 to 100 μm.

If the thickness of the can wall is thinned, when the protrusion is in contact with the outer surface of the can wall and is pushed in, the front end of the protrusion penetrates the can wall and is opened (pinhole), and the content is likely to occur. Leakage problem. Leakage of the contents, because the system causes major problems, it is difficult to open the protrusions even when the protrusions are pushed in even in the case of the thinned wall of the tank (in the spur resistance) There is a demand for materials for the aluminum can body and the aluminum can body.

Patent Document 1 describes an aluminum alloy for a can body. The gold plate contains Si, Fe, Cu, Mn, and Mg in a specific amount, and limits the number density and the area ratio of the intermetallic compound of a specific size on the surface of the plate to a specific range. According to the description of Patent Document 1, the can body obtained by performing DI molding on the aluminum alloy sheet is excellent in pinhole resistance (stud resistance). However, in the case of this aluminum alloy plate, the thickness of the can wall after DI molding is set to a thickness exceeding 110 μm, and does not correspond to the tendency of thinning described above.

Patent Document 2 describes an aluminum alloy plate for a can body which contains Si, Fe, Cu, Mn, and Mg in a specific amount and which has an intermetallic compound of a specific size on the surface and the cross section of the plate. The number density and area ratio are limited to a specific range. According to the description of the patent document 2, the can body obtained by DI-forming the aluminum alloy sheet is thinner than the thickness of the can wall of 90 to 95 μm (refer to the example of Patent Document 2). The spurt is still excellent. However, in the embodiment of Patent Document 2, the aluminum alloy sheet is subjected to film lamination and DI molding, and the can body system in the form of DI molding without performing film lamination is not considered. Most of the aluminum cans that are currently in the market are formed by DI molding without film lamination. From this point of view, the aluminum alloy plate described in the embodiment of Patent Document 2 can be said. There is a lack of generality.

Patent Document 3 describes an aluminum alloy sheet for a can body which contains Si, Fe, Cu, Mn, and Mg in a specific amount, and contains five or more of Mg and/or Cu atoms in total. The average density of a particular collection of atoms (atomic clusters) is limited to a specific range. According to the description of Patent Document 3, the can body obtained by DI-forming the aluminum alloy sheet is a secondary crystal grain of the can body structure after the can is an aluminum can body and after the baking treatment is applied. The promotion is promoted, and the stab resistance of the can body is improved.

[Previous Technical Literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2007-197815

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2009-270192

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2014-125677

Patent Document 3 describes that it is possible to obtain excellent spur resistance in a DI can in which the wall of the can is reduced in thickness. On the other hand, in the case of the aluminum alloy plate for the can body of the DI can, in addition to the above-mentioned spur resistance, tearing does not occur during DI processing and wrinkles occur at the bottom of the can of the DI can. There is a need for characteristics such as wrinkles which are generated in the range from the ground portion of the can bottom to the side wall. However, in a DI can in which the material is thinned, the can bottom wrinkles are likely to occur, and the DI can having the can bottom wrinkles is a defective appearance.

It is an object of the present invention to provide an excellent spur resistance even in a DI can which is thinned in a tank wall and even if it is It is also possible to obtain an aluminum alloy sheet for a can body which is excellent in the resistance to spurs in the DI can which has been subjected to DI molding without performing film lamination, and which does not wrinkle the bottom of the can.

If the work hardening energy (= uniform deformation energy) of the tank wall after the DI forming is increased, when the projection is pushed in from the outer surface of the tank wall and the tank wall is deformed, it becomes a board in which the tank wall is hard to occur. The thickness is reduced (shrinked), and the load (stab strength) that can be withstood until the breakage is increased. In the present invention, by limiting the relationship between the dislocation density of the aluminum alloy sheet and the lodging strength after baking to a specific range, the work hardening energy of the can wall after the DI forming is improved, and the DI can be obtained. Improved resistance to spurs after forming. At the same time, it is also possible to prevent the occurrence of wrinkles at the bottom of the can after the DI is formed.

The aluminum alloy plate for a can body of the present invention contains: Si: 0.1 to 0.5% by mass, Fe: 0.3 to 0.6% by mass, Cu: 0.1 to 0.35% by mass, Mn: 0.5 to 1.2% by mass, Mg: 0.7~ 2.5 mass%, and the residue is formed of Al and unavoidable impurities. The aluminum alloy sheet for the can body has a lodging strength after baking at 200 ° C for 20 minutes, and is 251 to 295 MPa, and the undulation strength (unit: MPa) after baking of the aluminum alloy sheet is used as a horizontal The axial dislocation density (unit: ×10 ¹⁴ /m ² ) at the center of the thickness of the plate measured by X-ray diffraction is shown in Fig. 4, the aforementioned lodging strength after baking and by X The dislocation density at the center of the plate thickness measured by the line diffraction is at the point A (251, 1.0 × 10 ¹⁴ ); the coordinate B (251, 8.0 × 10 ¹⁴ ); coordinates C (276, 8.0 ×) 10 ¹⁴ ); coordinates D (295, 14.2 × 10 ¹⁴ ); coordinates E (295, 1.0 × 10 ¹⁴ ) are in the range of polygons (including lines) surrounded by lines. The aluminum alloy plate for the can body contains one or more of Cr: 0.10% by mass or less, Zn: 0.40% by mass or less, and Ti: 0.10% by mass or less, depending on the demand.

The aluminum alloy sheet for a can body of the present invention is obtained by limiting the dislocation density to a specific range, even in the case where the wall of the can is formed by DI molding without laminating the film. The shape of the tank after DI forming and baking is also excellent in stab resistance. Thereby, in the case where the projections come into contact with the wall of the pot after filling, it is possible to prevent breakage of the tank wall after filling, and to prevent leakage of the contents. Further, in the aluminum alloy sheet for a can body of the present invention, by limiting the dislocation density to a specific range, it is possible to prevent wrinkles from occurring at the bottom of the can after the DI molding. Further, it has excellent drawing workability, and the can after the DI molding and baking has high pressure resistance.

The aluminum alloy sheet for a can body of the present invention may be subjected to DI molding after film lamination.

(pressure resistance test)

2‧‧‧Base plate

3‧‧‧Support

4‧‧‧Fixed components

5‧‧‧O-ring

6‧‧‧ Rubber tube

8‧‧‧ cans

(Spur strength test)

11‧‧‧ cans

12‧‧‧Support

14‧‧‧Spurs

[Fig. 1A] is a description of the procedure for the pressure resistance test of the can The figure is a side view of the can used in the compressive strength test.

Fig. 1B is a view for explaining the procedure of the pressure resistance test of the can, and is a side view of an important part of the pressure tester.

Fig. 1C is a view for explaining the procedure of the withstand voltage test of the can, and is a plan view of the withstand voltage tester shown in Fig. 1B.

[Fig. 2A] is a diagram for explaining the procedure of the pressure resistance test of the can, and is a side view when the can is fixed at the holder.

Fig. 2B is a view for explaining the procedure of the pressure resistance test of the can, and is a side view when the can bottom is buckled by internal pressure.

FIG. 3 is a cross-sectional view schematically illustrating a method of measuring the spur strength of the can body.

[Fig. 4] shows the relationship between the lodging strength after baking of the aluminum alloy sheet of the example and the dislocation density at the central portion of the sheet thickness measured by X-ray diffraction, the aluminum of the present invention. The alloy plate is included in the range of the polygon surrounded by the line connecting the points A to E.

Hereinafter, the aluminum alloy sheet for a can body of the present invention and a method for producing the same will be described in detail.

<Component composition of aluminum alloy plate> (Si: 0.1 to 0.5% by mass)

If the Si content is less than 0.1% by mass, the 0-180° ear becomes high during the DI molding, and the crack is easily generated during the drawing process. And the tear caused by this. On the other hand, when the Si content exceeds 0.5% by mass, since the unrecrystallized grains remain in the hot coil, the 45° ear system becomes high during the DI molding, and the stretching process is likely to occur. Cracked ears and tears caused by this. In addition, when the Si content exceeds 0.5% by mass, more Al—Fe—Mn—Si-based intermetallic compound or Mg—Si-based intermetallic compound is formed, and as a result, a force is applied to the tank wall. When the tank wall is deformed, the formation of voids around the compound and the propagation of cracks are promoted, and the stab resistance is lowered.

(Fe: 0.3 to 0.6% by mass)

When the Fe content is less than 0.3% by mass, since the non-recrystallized grains remain in the hot rolled sheet, the 45° ear system becomes high during the DI molding, and the cracking during the drawing process is likely to occur. The tear caused by this. On the other hand, when the Fe content exceeds 0.6% by mass, the Al—Fe—Mn-based intermetallic compound increases, and tearing is likely to occur during the drawing process. In addition, when the Al-Fe-Mn-based intermetallic compound is increased, when the tank wall is deformed by applying a force to the tank wall, the formation of voids around the compound and the propagation of cracks are promoted, and the resistance to spurs is lowered. .

(Cu: 0.1 to 0.35 mass%)

If the Cu content is less than 0.1% by mass, the strength is insufficient and the pressure resistance of the can is insufficient. On the other hand, when the Cu content exceeds 0.35 mass%, the strength is excessively increased, and tearing is likely to occur during the stretching process.

(Mn: 0.5 to 1.2% by mass)

If the Mn content is less than 0.5% by mass, the strength is insufficient and the pressure resistance of the can is insufficient. On the other hand, when the Mn content is more than 1.2% by mass, the Al-Fe-Mn-based intermetallic compound is increased, and tearing is likely to occur during the drawing process. In addition, when the Al-Fe-Mn-based intermetallic compound is increased, when the tank wall is deformed by applying a force to the tank wall, the formation of voids around the compound and the propagation of cracks are promoted, and the resistance to spurs is lowered. .

(Mg: 0.7 to 2.5% by mass)

If the Mg content is less than 0.7% by mass, the strength is insufficient and the pressure resistance of the can is insufficient. Further, the work hardening energy (uniform deformation energy) is insufficient, and when the tank wall is deformed by applying a force to the tank wall, the shrinkage tends to occur, and the spur resistance is lowered. On the other hand, when the Mg content exceeds 2.5% by mass, the strength is excessively increased, and tearing is likely to occur during the stretching process. In order to obtain particularly excellent characteristics in connection with the tensile workability, the pressure resistance of the can, and the stab resistance, the ideal lower limit of the Mg content is 1.0% by mass, and the ideal upper limit is 1.8% by mass.

(Cr: 0.10% by mass or less)

If the Cr content is 0.10% by mass or less, the material properties of the aluminum alloy sheet and the characteristics of the can after the DI molding are not affected. ring. Although Cr is an unavoidable impurity, in order to reduce the cost, for example, it is also possible to increase the blending ratio of the scrap (including scrap containing a large amount of Cr) in the raw material, and to actively add Cr within the above range. . However, when the Cr content exceeds 0.10% by mass, unrecrystallized grains remain in the hot coil, and in the DI molding, the 45° ear system becomes high, and the cracking during the drawing process is likely to occur and the cause is caused by This caused the tear. Therefore, the Cr content in the aluminum alloy is limited to the above range.

(Zn: 0.40% by mass or less)

When the content of Zn is 0.40% by mass or less, the material properties of the aluminum alloy sheet and the tank characteristics after DI molding are not affected. Zn is an unavoidable impurity. However, in order to reduce the cost, for example, it is possible to increase the blending ratio of the scrap in the raw material (waste of the heat exchanger packaging material, etc.), and to actively add Zn within the above range. .

(Ti: 0.10% by mass or less)

Ti is added for the purpose of miniaturization of ingot crystal grains. When the ingot structure is made fine at the time of casting, the castability is improved, and high-speed casting is possible. This effect is obtained by adding 0.01% by mass or more. On the other hand, if Ti is added in an amount of more than 0.10% by mass, the clogging of the screen will become faster, and the casting system will gradually become difficult to pass through the screen during casting, and finally the casting has to be stopped. Therefore, the Ti content in the aluminum alloy is limited to the above range. Inside. Further, in the case where Ti is added, the ingot refiner (Al-Ti-B) having a mass ratio of Ti and B of 5:1 is added to the pre-casting state in the form of a cake or a rod. In the melt soup, therefore, B corresponding to the content ratio is also inevitably added.

(other inevitable impurities)

The unavoidable impurities (V, Na, Zr, Ni, Ca, etc.) other than the above-mentioned elements are not contained in an amount of 0.05% by mass or less, and the total amount is 0.15% by mass or less. The material properties and the characteristics of the can after forming the DI are affected. In addition, as for the elements, the same is true, as long as it does not exceed the above-mentioned content, even when it is contained as an unavoidable impurity, even if it is intended to blend the waste containing the elements. When the rate is increased and the enthusiasm is added, the effect of the present invention is not hindered.

<Characteristics of Aluminum Alloy Sheet> (falling strength after baking: 251~295MPa)

If the fall strength of the aluminum alloy sheet after baking at 200 ° C for 20 minutes is less than 251 MPa, the strength is insufficient, and the pressure resistance of the can after DI molding and baking may be insufficient. On the other hand, if the fall strength of the aluminum alloy sheet after baking at 200 ° C for 20 minutes is more than 295 MPa, the strength is excessively increased, and tearing is likely to occur during the drawing process, and the productivity is lowered. In addition, the strength after baking is related to the strength before baking, and the strength after baking is a large aluminum alloy plate, before baking (stretching processing) The strength of the former is also large. The lodging strength after baking is preferably set to 250 MPa or more.

(Dislocation density at the center of the plate thickness)

The term "dislocation" refers to a defect in a line shape or a rib shape which is introduced into an aluminum alloy sheet for a can body due to cold rolling. These dislocations can be identified as a line or a rib by a transmission electron microscope at a magnification of 50,000 times. If the dislocation density is large, the dislocation of the dislocations will result in a forest dislocation, which will become an obstacle to the movement of other dislocations, and the intensity will increase.

The relationship between the dislocation density at the center portion of the thickness of the aluminum alloy sheet of the present invention and the drop strength after baking at 200 ° C for 20 minutes is shown in Fig. 4 . 4 is a dislocation density at the central portion of the thickness of the aluminum alloy plate measured by X-ray diffraction after the buckling strength (unit: MPa) after baking of the aluminum alloy plate is taken as the horizontal axis ( Unit: ×10 ¹⁴ /m ² ) As the vertical axis, and the vertical axis is a single logarithmic line graph of the natural logarithmic scale. The value of the dislocation density of the aluminum alloy sheet of the present invention and the strength of the post-baking stress is limited to the line connecting the point A, the point B, the point C, the point D, and the point E shown in FIG. Within the range of the enclosed polygon (also including the line). In addition, the coordinates (X, Y) of each point when the horizontal axis is the X axis and the vertical axis is the Y axis is the point A (251, 1.0 × 10 ¹⁴ ); the point B (251, 8.0 × 10 ¹⁴ ); point C (276, 8.0 × 10 ¹⁴ ); point D (295, 14.2 × 10 ¹⁴ ); point E (295, 1.0 × 10 ¹⁴ ).

When the dislocation density at the center portion of the thickness of the aluminum alloy sheet is less than 1.0 × 10 ¹⁴ /m ² , the work hardening at the time of drawing processing becomes large, and tearing is likely to occur. On the other hand, if the dislocation density exceeds 8.0 × 10 ¹⁴ /m ² , the work hardening energy (uniform deformation energy) of the can wall after DI molding and baking is insufficient, and the can is applied to the tank wall to apply force. When the wall is deformed, the shrinkage tends to occur, the spur resistance is lowered, and the bottom of the can is easily broken. However, when the strength of the aluminum alloy sheet after baking is in the range of 276 to 295 MPa, the dislocation density may exceed 8.0 × 10 ¹⁴ /m ² . More specifically, in the region below the line connecting the points C (276, 8.0 × 10 ¹⁴ ) and the point D (295, 14.2 × 10 ¹⁴ ) shown in Fig. 4, it is possible to form and The wall of the can after baking is appropriately imparted with work hardening energy, the stab resistance is not lowered, and the occurrence of wrinkles at the bottom of the can is also prevented.

By controlling the value of the dislocation density at the central portion of the thickness of the aluminum alloy plate and the value of the lodging strength after baking to the above range, it is possible to prevent tearing during the drawing process, and to ensure DI forming and baking. The pressure resistance of the can, and imparting good work hardening energy to the can wall, provides excellent resistance to spurs and prevention of wrinkles at the bottom of the can.

<Method of Manufacturing Aluminum Alloy Sheet>

The aluminum alloy sheet of the present invention can be produced by various processes of casting, homogenization heat treatment, hot rolling, and cold rolling. The intermediate annealing (also referred to as rough annealing) after the inter-heat rolling and the intermediate annealing in the middle of the cold rolling and the finishing annealing after the cold rolling are not performed. Moreover, the method for producing an aluminum alloy sheet of the present invention is preferably carried out by a tandem calender. The cold is calendered, and the winding temperature is increased, and the cooling rate of the specific temperature region is controlled to be low during the cooling after winding. Thereby, the recovery of the material during the cold rolling and after the winding is promoted, and the dislocation density of the aluminum alloy plate (product plate) can be controlled within the above range.

Hereinafter, each project will be described.

First, an aluminum alloy is cast by a known semi-continuous casting method such as a DC casting method.

Next, after removing the region of the ingot surface which is a non-uniform structure by surface cutting, a homogenization heat treatment is applied based on a usual method. In this case, a two-stage homogenization heat treatment or a two-time homogenization heat treatment may be employed. The so-called two-stage homogenization heat treatment here means that after the ingot is held at a high temperature for a certain period of time (the homogenization heat treatment in the first stage), it is not always cooled to room temperature, and is more than 200 ° C. The cooling is stopped at the temperature and maintained at this temperature for a specific period of time (homogenization heat treatment in the second stage). In addition, the secondary homogenization heat treatment is performed by temporarily cooling the ingot at a high temperature for a certain period of time (the first homogenization heat treatment), and then temporarily cooling to a temperature of 200 ° C or lower including room temperature. The heating is again carried out and maintained at a specific homogenization treatment temperature for a specific period of time (the second homogenization heat treatment).

After the homogenization heat treatment, the inter-heat rolling is continued without cooling, and it is preferable to terminate the inter-heat rolling at 300 ° C or higher. The heat-rolled rolled material produced is a recrystallized structure.

Then, the cold rolling is performed by one process by a tandem calender, or by calendering by a single calender. In the case, it is carried out by a so-called continuous process of immediately performing the next process after one process. By performing the cold rolling in the first process of the tandem calender or the continuous process of the single calender, the heat generation in the cold rolling is increased, and the dynamic recovery of the material and the recovery after winding are promote. Further, from the viewpoint of production efficiency, it is desirable to use calendering by a tandem calender.

The total rolling ratio of cold rolling is set to 80 to 90%. This rolling rate is achieved by a pass plate which is caused by a tandem calender or a pass plate which is a process of a plurality of single calenders. If the total rolling ratio in the cold rolling is less than 80%, the strength of the aluminum alloy sheet is insufficient, and the pressure resistance of the can after DI forming and baking may be insufficient. On the other hand, if the total rolling ratio exceeds 90%, the strength becomes excessively large, and an increase of 45° ear is caused, and cracking and tearing due to this are liable to occur during the drawing process. In order to increase the processing heat and increase the winding temperature and set the dislocation density in the range specified in the present invention, it is necessary to perform processing at a high temperature by a work roll having a small diameter. Specifically, it is necessary to perform cold rolling by a work roll having a diameter of 650 mm or less, and it is preferable to perform cold rolling by a work roll having a diameter of 450 mm or less.

The winding temperature after cold rolling is preferably 150 ° C or higher. By increasing the winding temperature, the recovery of the material is promoted, the dislocation density of the aluminum alloy plate (product plate) is reduced to the above range, and the work hardening energy (uniform deformation energy) of the can wall after DI forming and baking The system is lifted, the occurrence of wrinkles at the bottom of the tank is prevented, and the stab resistance is improved. On the other hand, if the winding temperature exceeds 180 ° C, excessive recovery occurs, and the dislocation density is further lowered within the above range. As a result, the work hardening at the time of the stretching process becomes large, and tearing is likely to occur. Further, the softening of the aluminum alloy sheet due to the heat generation during processing becomes large, and the sheet fracture is likely to occur during rolling. As a result, since the productivity of the aluminum alloy sheet is greatly reduced, it is not practical in practical use. Therefore, the winding temperature after cold rolling is preferably 150 ° C or higher, more preferably 160 ° C or higher, and the upper limit is 180 ° C.

Further, in the temperature region (temperature region of 120 ° C or higher) from the winding temperature up to 120 ° C, the average cooling rate of the coil is set to 15 ° C / hr or less. By setting the cooling rate to 15 ° C / hr or less, the recovery of the material is promoted, and the dislocation density of the aluminum alloy plate (product plate) is lowered to the above range, and the DI forming and baking cans are The work hardening energy (uniform deformation energy) of the wall is improved, the occurrence of wrinkles at the bottom of the tank is prevented, and the stab resistance is improved. When the cooling rate in the temperature region above 120 ° C is more than 15 ° C / hr, the recovery of the material is not sufficient, the dislocation density is not sufficiently reduced, and the DI is formed and the wall of the can after baking The work hardening energy system will be insufficient, and it will easily cause wrinkles at the bottom of the tank, and the stab resistance will be reduced.

[Examples]

Hereinafter, the examples for confirming the effects of the present invention will be compared with the comparative examples which do not satisfy the requirements of the present invention, and will be specifically described. In addition, the present invention is not limited by this embodiment. By.

The aluminum alloy having the composition shown in Tables 1 and 2 was melted, and an ingot having a thickness of 600 mm was produced by a semi-continuous casting method (excluding No. 12 of Comparative Example). The surface layer of the ingot was subjected to face cutting, and a homogenization heat treatment was applied, followed by hot inter-calendar rolling and hot-end finishing treatment calendering. Thereafter, the intermediate annealing zone is not applied, and the inter-heating rolled material is subjected to cold rolling (in-line calender or single calender) to form an aluminum alloy plate (rolling plate) having a thickness of 0.27 mm, and is wound. . The finish annealing after cold rolling was not performed (except No. 19 of Comparative Example). Further, in No. 12 of the comparative example, the clogging of the sieve was caused, and casting was impossible.

In Tables 1 and 2, the type of calender used in cold rolling, the total rolling ratio of cold rolling, the winding temperature after cold rolling, and the average cooling rate of the coil after winding (from the roll The presence and absence of the finish annealing after cold rolling and the conditions are described. In the case where the inter-column rolling was performed by the tandem rolling mill, the total rolling ratios described in Tables 1 and 2 were achieved by one pass.

The manufactured aluminum alloy sheets of Examples No. 1 to 22 and Comparative Examples No. 1 to 11 and 13 to 19 were used as test materials, and the post-baking strength and dislocation were determined according to the following methods. The density was measured. The results are shown in Table 3.

<After Baking Strength of Aluminum Alloy Sheet>

After baking at 200 ° C for 20 minutes for the test material (aluminum alloy sheet), the JIS No. 5 test piece was taken in the parallel direction of the rolling, and the tensile test was carried out in accordance with the provisions of JIS Z 2241 to reduce the 0.2%. The strength was measured. When the 0.2 drop strength was in the range of 240 to 295 MPa, it was evaluated as acceptable.

<Dislocation density of aluminum alloy sheets>

In the present invention, the dislocation density is measured by X-ray diffraction. A densely distributed linear or rib-shaped dislocation (cell wall or shear band) in a dislocation is difficult to discriminate in a transmission electron microscope, and may be a measurement error in obtaining a dislocation density ρ. . On the other hand, in the X-ray diffraction, as will be described later, since the dislocation density ρ is calculated based on the half width of the diffraction peak from each of the faces in the collective structure, there is even if there is This kind of forest error will also have fewer advantages.

In a structure in which dislocations are introduced by plastic deformation such as cold stretching, lattice distortion is generated centering on dislocations. Moreover, by the arrangement of dislocations, low angle grain boundaries, cell structures, etc. Da. If the dislocation and the domain structure accompanying this are grasped based on the X-ray diffraction pattern, a characteristic enlargement and shape corresponding to the diffraction index appear in the diffraction pattern. The shape (line profile) of the diffraction peak can be analyzed (line profile analysis) to extract the dislocation density.

First, according to the X-ray diffraction of the center portion of the thickness of the test material (aluminum alloy plate), the surface of each of the main directions in the aggregate structure of the center portion of the plate thickness is extracted. Half the width of the diffraction peak. If the dislocation density ρ is higher, the half width of the diffraction peak of each of these faces becomes larger.

In addition, the X-ray diffraction test uses an X-ray diffraction device manufactured by RIGAKU Co., Ltd., and uses Cu in the target, and has a tube voltage of 45 kV, a tube current of 200 mA, a scanning speed of 1 °/min., and a sampling width. The conditions of 002° and measurement range (2θ) of 30° to 145° were implemented.

Next, based on the half width of the diffraction peaks of the respective faces, the lattice deformation (crystal deformation) ε was taken out by the Williamson-Hall method, and the dislocation density ρ was calculated according to the following formula. In the following formula, b is the size of the Burgers vector, and this time, b = 2.8635 × 10 ^-10 m is used.

ρ=16.1×ε ² /b ²

The X-ray diffraction test was carried out at one of five sites (both in the center of the plate thickness) for one test material, and the average dislocation density was calculated based on the obtained results.

Next, the aluminum alloy sheets of Examples No. 1 to 22 and Comparative Examples Nos. 1 to 11 and 13 to 19 were used. And made a DI can. As a producer In the first method, a blank of 140 mm in diameter was punched out from an aluminum alloy plate, and the blank was subjected to drawing forming to prepare a cup having a diameter of 90 mm. With respect to the obtained cup, DI forming (re-extension + drawing processing) was performed by a general-purpose aluminum can body forming machine, and a DI can was produced.

The produced DI can has an outer diameter of 66.3 mm, a thickness of the thinnest wall portion of the can wall (a height of 60 mm from the bottom of the can) of 90 μm, and a processing ratio of this portion of 66.7% (initial thickness: 270 μm) ).

Each of the examples and the comparative examples was continuously molded into 10,000 cans by the aluminum can body molding machine, and the tensile workability (DI processability) was evaluated in accordance with the following method. Next, using the formed can, the measurement of the withstand voltage and the spur strength and the evaluation of the bottom wrinkles were carried out in accordance with the method shown below. The results are shown in Table 3. Further, in Comparative Examples No. 6, 10, and 16, in the continuous molding by the aluminum can body molding machine, since a large amount of tearing occurred, the pressure strength and the spur strength were not measured. .

(stretching workability)

Among the 10,000 cans which were continuously formed, the cans having the problem of tearing or the like were evaluated to be acceptable (○), and those having 4 or more were evaluated as unacceptable (×).

(the pressure resistance of the can)

The body portion of the produced DI can (can body portion) was trimmed to have a height of 100 mm, and baked at 200 ° C for 20 minutes. Connect Using a hydraulic pressure tester (hydraulic pressure-reducing buckling tester manufactured by ACETECH Co., Ltd., type name WBT-500), and making the internal pressure of the DI tank after baking And measured the maximum internal pressure at the bottom of the tank when the buck occurred.

As shown in FIG. 1B and FIG. 1C, the pressure tester is provided with a base plate 2 provided on the machine table 1, and a cylindrical holder 3 provided on the base plate 2, and A pair of fixing members 4, 4 disposed at both sides of the holder 3. At the intermediate position in the height direction of the holder 3, an O-ring 5 is provided. Inside the holder 3, a rubber tube 6 is provided, which extends downward through the base plate 2 and is connected to the water passage, and is connected to the water pressure gauge, the switching valve, or the like. The hydraulic pump is connected (not shown). At the base plate 2, a hole 7 is formed which is connected to the vent line and is connected to the vacuum pump via a switching valve or the like (none of which is shown). The fixing members 4 and 4 are advanced and retracted by hydraulic cylinders (not shown).

The withstand voltage test was carried out as follows.

(1) As shown in Figs. 1A to 1C, the can 8 is fitted to the holder 3 with the can bottom facing, and then the fixing members 4, 4 are advanced for a specific stroke. If the fixing members 4, 4 reach a specific position (refer to FIG. 2A), the front ends of the fixing members 4, 4 are at a position slightly below the O-ring 5 to push the tank wall of the tank 8 from both sides, and The can 8 is fixed at the holder 3. Thereby, the inner surface of the can wall of the can 8 is adhered to the periphery of the O-ring 5, and the inside of the holder 3 (in the can 8) is sealed except for the place of the rubber tube 6 and the hole 7.

(2) The vacuum pump is operated, and the inside of the holder 3 (inside the tank 8) is deaerated to 9.8 kPa (0.1 kgf/cm ² ) or less through the hole 7, and then the vent line is closed.

(3) The hydraulic pump is operated, and water is supplied from the rubber tube 6 to the inside of the holder 3 (inside the tank 8). The water pressure in the holder 3 (in the tank 8) (measured by the aforementioned water pressure gauge) rises slightly in proportion to the elapsed time from the start of supply, and at the moment when the bottom of the tank is wrinkled reduce. The maximum internal pressure at the time of the wrinkling of the bottom of the can occurs as the pressure resistance of the can. In Fig. 2B, the state when the wrinkle of the can bottom occurs is shown.

The case where the pressure resistance was 618 kPa or more (6.3 kgf/cm ² or more) was evaluated as acceptable.

(spur strength)

The opening of the prepared DI can was trimmed to a height of 100 mm, and baking was performed at 200 ° C for 20 minutes. Thereafter, as shown in FIG. 3, the opening of the can 11 was fixed to the holder. 12 and sealed. Next, air is supplied from the vent line 13 to the inside of the tank, and the internal pressure of ² kgf/cm ² is applied, and the steel spur needle 14 having a hemispherical surface having a radius of 0.5 mm at the tip end is vertically at the speed of the tank wall. 50mm/min to make a spur. The portion where the burrs are formed by the burrs 14 is a portion where the rolling direction of the aluminum alloy plate and the direction of the can axis coincide with each other and the height L of the bottom of the can is 60 mm. The load until the spur needle 14 penetrates the can wall is continuously measured, and the obtained maximum load is used as the spur strength. Those who have a spur strength of 35 N or more are evaluated as qualified.

(Evaluation of the bottom of the tank)

Any 30 cans were selected from the DI cans produced by the can body forming machine, and the range from the ground portion of the can bottom to the side walls was observed by visual observation for each can. The case where the bottom of the can is not wrinkled in any of the selected 30 cans is evaluated as acceptable (○), and any occurrence in any of the selected 30 cans will occur. The case where the bottom of a can was wrinkled was evaluated as unacceptable (x). Further, in the above-described can body molding machine, the stretching was carried out under the conditions of suppressing the air pressure of 50 psi and the stretching die R of 2.0 mm by wrinkles. Moreover, the diameter of the ground portion of the bottom of the produced DI can is 48mm.

The values of the dislocation density and the post-baking drop strength described in Table 3 are plotted and shown in FIG.

As shown in Tables 1, 3 and 4, the composition of the aluminum alloy, the lodging strength after baking, and the dislocation density are within the requirements of the present invention. The aluminum alloy sheets of Examples Nos. 1 to 22 in the range were excellent in the stretchability, and the pressure resistance and the spur strength of the can were large, and the bottom of the can was not wrinkled. In this manner, in Examples Nos. 1 to 22, the thickness of the can wall was 90 μm and was thin, and the film lamination was not performed in the DI molding, but it was excellent in sting resistance and also It can prevent the occurrence of wrinkles at the bottom of the tank. In Examples Nos. 1 to 22, cold rolling, winding, and cooling after winding were performed within the range of the conditions described above.

In addition, it is presumed that the aluminum alloy sheets of Examples No. 1 to 22 have excellent spur resistance, and the work hardening energy (= uniform deformation energy) of the tank wall is improved, and the spur needle 14 is pushed. When the tank wall is deformed and the tank wall is deformed, it is difficult to reduce the thickness of the tank wall (shrinkage). The can formed by DI molding using the aluminum alloy sheets of Examples No. 1 to 22 prevents the tank wall from being broken when the projections are brought into contact with the filled tank wall, thereby preventing the occurrence of contents. The leaking situation. Moreover, the aluminum alloy plate of Examples No. 1 to 22 can prevent the occurrence of wrinkles at the bottom of the can, and it is presumed that the can body forming machine is performed by increasing the work hardening energy of the material. At the time of re-stretching, the forming force (tension) in the direction of the can axis is increased, and as a result, the buckling in the circumferential direction of the can (= occurrence of wrinkles) is suppressed.

On the other hand, as shown in Tables 2, 3, and 4, one of the compositional composition of the aluminum alloy, the lodging strength after baking, and the dislocation density is Comparative Example No. falling within the predetermined range of the present invention. .1~11, 13~19 aluminum alloy sheets, one of the evaluations of the tensile processability, the pressure resistance of the can, the spurt, and the bottom wrinkles of the tank are not satisfied with the hair. The benchmark of the Ming.

In Comparative Example No. 1, since the Si content was insufficient, the drawability was poor. In Comparative Example No. 2, since the Si content was excessive, the stretch workability was poor, and the stab resistance was also poor.

In Comparative Example No. 3, since the Fe content was insufficient, the drawability was poor. In Comparative Example No. 4, since the Fe content was excessive, the drawability was poor, and the stab resistance was also poor.

In Comparative Examples No. 5, 7, and 9, since the content of Cu, Mn, and Mg was insufficient, the lodging strength after baking was insufficient, and the pressure resistance of the can was poor. Comparative Example No. 9 was also inferior in stab resistance. In Comparative Examples Nos. 6 and 10, since the Cu and Mg contents were excessive, the fall strength of the aluminum alloy sheet after baking was too large, and the stretch workability was poor. In Comparative Examples No. 8 and 11, since the content of Mn and Cr was excessive, the tensile processability was poor. Comparative Example No. 8 was also inferior in stab resistance. In No. 12, since the Ti content was excessive, casting was not possible as described above.

In Comparative Example No. 13, since the total rolling ratio of the cold rolling was insufficient, the lodging strength after baking was insufficient, and the pressure resistance was poor. In Comparative Example No. 14, since the total rolling ratio was excessively large, the fall strength of the aluminum alloy sheet was excessively large, and the drawability was poor.

In Comparative Example No. 15, the winding temperature was low, the recovery after the dynamic recovery and the winding was insufficient, the dislocation density of the aluminum alloy sheet was high, and the stab resistance of the can was poor, and occurred. The bottom of the can is wrinkled. In Comparative Example No. 16, the winding temperature was high, and the dislocation density of the aluminum alloy sheet was lowered, and the stretching was performed. The engineering system is poor.

In Comparative Example No. 17, the cooling rate from the winding temperature to the temperature region of 120 ° C was large, and the recovery after winding was insufficient, and the dislocation density of the aluminum alloy plate was high, and the can was The stab resistance was poor, and the bottom of the can was wrinkled.

In Comparative Example No. 18, cold rolling was performed by a single calender, and there was time between the process and the process. Therefore, the winding temperature was low, the dynamic recovery, and the recovery after winding. Insufficient, the dislocation density of the aluminum alloy sheet is high, the stretch workability and the stab resistance of the can are poor, and the bottom of the can is wrinkled. In Comparative Example No. 19, the inter-column rolling was performed by a single calender, and there was time between the process and the process. Therefore, the winding temperature was low, the dynamic recovery, and the recovery after winding. It is not sufficient, and the effect of finishing annealing is also small, the dislocation density is high, the toughness resistance of the can is poor, and the bottom of the can is wrinkled.

Although the present invention has been described with reference to the embodiments of the present invention, it is obvious to those skilled in the art that various changes or modifications may be made without departing from the spirit and scope of the invention. Corrected.

This application is based on the Japanese franchise (Japanese Patent Application No. 2015-055910) filed on March 19, 2015, and the Japanese franchise (Japanese Patent Application No. 2015-245939) filed on December 17, 2015. This is referred to as a reference.

[Industrial use possibility]

The aluminum alloy plate for the can body of the present invention, even if the tank wall is In the case of a DI tank that has been thinned and a DI tank that has been subjected to DI molding without film lamination, it is also possible to have excellent spur resistance and prevent wrinkles at the bottom of the tank, in particular, It is useful when it is used as a can body for a 2-piece can.

11‧‧‧ cans

12‧‧‧Support

13‧‧‧Ventilation line

14‧‧‧Spurs

L‧‧‧ Height from the bottom of the tank

Claims (3)

An aluminum alloy plate for a can body, comprising: Si: 0.1 to 0.5% by mass, Fe: 0.3 to 0.6% by mass, Cu: 0.1 to 0.35% by mass, Mn: 0.5 to 1.2% by mass, Mg: 0.7 to 2.5% by mass, and the residual portion is formed of Al and unavoidable impurities, and the lodging strength after baking at 200 ° C for 20 minutes is 251 to 295 MPa, and the aforementioned lodging strength after baking is borrowed. The relationship between the dislocation density at the center of the thickness of the plate as measured by the X-ray diffraction is based on the dangling strength (unit: MPa) after baking of the aluminum alloy plate as the X-axis and by the X-ray. The dislocation density (unit: ×10 ¹⁴ /m ² ) at the center of the plate thickness measured by diffraction is taken as the Y-axis line graph, and falls on the coordinates A, B, C, D, and E described below. Within the range of the polygon surrounded by the lines connecting the points: coordinates A (251, 1.0 × 10 ¹⁴ ); coordinates B (251, 8.0 × 10 ¹⁴ ); coordinates C (276, 8.0 × 10 ¹⁴ ); coordinates D (295, 14.2 × 10 ¹⁴ ); coordinates E (295, 1.0 × 10 ¹⁴ ). An aluminum alloy sheet for a can body according to the first aspect of the invention, which contains Cr: 0.10% by mass or less, Zn: 0.40% by mass or less, and Ti: 0.10% by mass or less, and one or more of the above. . The aluminum alloy sheet for a can body according to the first or second aspect of the invention, wherein the aluminum alloy has a Mg content of 1.0 to 1.8% by mass.