JP2006283113A - Aluminum alloy sheet for drink can barrel, and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aluminum alloy sheet for a drink can barrel having excellent bottom wrinkle properties, also capable of obtaining high can barrel strength, and producible with high production accuracy and productivity, and to provide a method for producing the same. <P>SOLUTION: The aluminum alloy sheet for a drink has a composition containing, by mass, 0.10 to 0.25% Si, 0.5 to 1.5% Mn, 0.8 to 1.5% Mg, 0.35 to 0.5% Fe, 0.1 to 0.3% Cu, Ti, B, and the balance Al with inevitable impurities. By suitably controlling the particle diameter and volume fraction of intermetallic compounds, its working hardenability is retained to the fixed one or above, so as to realize production with high accuracy, by controlling its electric conductivity to 30.0 to 39.0% IACS, the degree of elute elements to enter into solid solution in the Al matrix is regulated, and the tensile strength of a blank is controlled to ≤320 MPa to prevent the deformation resistance of the material from being made excessive during forming. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

    TECHNICAL FIELD The present invention relates to an aluminum alloy plate for beverage can bodies used as a can body material for various beverage cans such as carbonated beverages, beer and soft drinks, and a method for producing the same.

As the can body of beverage cans made of aluminum alloy, oil is applied to the aluminum alloy plate, cupping and DI molding (Draw-Ironing) are applied to form the can body, and trimming, cleaning, drying, outer surface and inner surface 2. Description of the Related Art Two-piece cans are often used that are painted, baked, necked, and flanged, filled with a beverage, and then the can lid is tightened.
The aluminum alloy sheet is manufactured by subjecting an aluminum alloy ingot to homogenization, hot rolling, then annealing as necessary, and then cold rolling. Usually, in addition to this, finishing treatments such as annealing, degreasing, washing, and lubricating oil application are performed.

  In recent years, due to the need for cost reduction of beverage cans, the thickness of the can body has been reduced (gauge down) and the diameter of the can lid has been reduced. Thinning the can body weakens the forming force during drawing, which increases the amount of material flowing into the can bottom chime, making it easy to buckle and constrict, resulting in an appearance defect called can bottom wrinkle. Let In addition, reducing the diameter of the can bottom requires a reduction in the ground diameter of the bottom of the can in order to ensure stackability when the cans are stacked together. In order to easily cause a buckling phenomenon in the chime portion, bottom wrinkle generation is promoted.

With reference to FIG. 1, the mechanism of the occurrence of the above bottom wrinkles will be described.
The thinning of the beverage can body 1 increases the amount of material flowing from the can side wall 2 to the can bottom chime portion 3 to easily cause buckling and constriction. 3a ... is generated. Further, it is necessary to reduce the diameter of the bottom of the can bottom, which is the diameter of the can bottom grounding portion 4, by reducing the diameter of the can lid (not shown). The bending phenomenon is likely to occur, and this also promotes the generation of the bottom wrinkles 3a, 3a.

  As an aluminum alloy plate for can barrels that can solve the above problems and can be used for thinning the can barrel and reducing the diameter of the can lid, and a manufacturing method thereof, Patent Document 1 discloses Mg, Mn, Fe. , Si, Cu, and Ti are defined, the tensile strength and elongation rate are regulated, and further, homogenization treatment, hot rolling, and cold rolling comprising three passes in which the cold-rolling outlet temperature is controlled. Improvement methods have been proposed.

Furthermore, Patent Document 2 defines the contents of Cu, Mg, Mn, Fe and Si, regulates mechanical properties that affect can bottom molding such as elongation, work hardening index and proof stress, homogenization treatment and hot work. An improved method has been proposed in which rolling is performed sequentially, and then the outlet temperature and cooling rate of cold rolling are controlled.
JP 2001-262261 A JP 2004-3000537 A

It has been clarified that the bottom wrinkle is improved by lowering the strength of the aluminum alloy sheet and increasing the elongation of the element. In order to increase this elongation, annealing after cold rolling is performed. It is effective to apply the treatment.
However, performing an annealing treatment after cold rolling has a problem of increasing the cost due to a decrease in productivity and reducing the strength of the can body. Furthermore, in order to cope with further thinning of the can body and reduction in the diameter of the can lid in the future, a material having high can body strength and excellent bottom wrinkle property is indispensable.

  Based on such a request, in the aluminum alloy plate for can bodies excellent in can bottom formability described in Patent Document 1 and the manufacturing method thereof, it is proposed to perform cold rolling consisting of three passes with controlled outlet temperature. It was. However, although this aluminum alloy plate and its manufacturing method are extremely effective means, they do not clarify the conditions directly necessary for obtaining a material having high can barrel strength and excellent bottom wrinkling properties. Further study was necessary in terms of realizing highly accurate and highly efficient productivity.

  On the other hand, Patent Document 2 simply defines that the elongation is 5.5% or more, the work hardening index is 0.06 or more, and the proof stress is 290 N / mm 2 or less. Consideration as a reliable means to achieve the quality required for plates is still inadequate, making it possible to produce highly accurate and highly efficient materials with high can barrel strength and excellent bottom wrinkling properties. However, it is not possible to substantially meet the demand for the future reduction in the thickness of the can body and the reduction in the diameter of the can lid.

    In view of the above problems in the prior art, the present invention provides a beverage can that is excellent in bottom wrinkle and has high can body strength, can be further thinned, and can be produced with high production accuracy and productivity. An object of the present invention is to provide an aluminum alloy plate for a trunk and a method for producing the same.

  In order to solve the above-mentioned problems, the present inventors have conducted intensive research. As a result, in order to achieve excellent bottom wrinkle and high can body strength, an aluminum alloy containing a predetermined amount shown in the present invention alloy is an intermetallic compound. The present inventors have found that the work hardenability can be effectively increased by optimally controlling the distribution state (particle diameter, volume fraction), and have arrived at the aluminum alloy plate for beverage can bodies of the present invention. Further, the aluminum alloy sheet of the present invention is configured by optimally controlling the cold rolling process of the cold rolling pass outlet temperature and the total rolling rate for the aluminum alloy containing the predetermined amount shown in the alloy of the present invention. Thus, the inventors have found that the electrical conductivity can be appropriately set, and have arrived at the method for producing an aluminum alloy plate for beverage can bodies of the present invention.

  The aluminum alloy plate for beverage can bodies of the present invention is Si: 0.10 to 0.25% (mass%, the same applies hereinafter), Mn: 0.5 to 1.5%, Mg: 0.8 to 1.5% Fe: 0.35 to 0.5%, Cu: 0.1 to 0.3%, Ti: 0.1% or less, B: 0.1% or less, the balance being Al and inevitable impurities An aluminum alloy plate comprising, as material properties, an intermetallic compound having a particle size of 0.1 to 1.0 μm having a volume fraction of 1 to 5% and an electrical conductivity of 30.0 to 39.0% IACS The tensile strength in the rolling direction of the base plate is 320 MPa or less, and the strength after baking is 250 MPa or more in terms of the yield strength in the rolling direction.

  The above-mentioned coating baking applied to the aluminum alloy plate for beverage can bodies according to the present invention is held at 180 to 220 ° C. for 5 to 30 minutes or at the maximum reached temperature of 210 to 260 ° C. for 2 minutes or less. It can be.

  The manufacturing method of the aluminum alloy plate for beverage can bodies of the present invention is as follows: Si: 0.10 to 0.25%, Mn: 0.5 to 1.5%, Mg: 0.8 to 1.5%, Fe: Aluminum containing 0.35 to 0.5%, Cu: 0.1 to 0.3%, Ti: 0.1% or less, B: 0.1% or less, the balance being Al and inevitable impurities After producing an alloy ingot and chamfering the aluminum alloy ingot, it is subjected to a homogenization treatment at a temperature of 550 to 620 ° C., and after the furnace is left out, the time until hot rolling starts within 30 minutes, The rolling is performed with the rolling end temperature set at 250 to 350 ° C., and the volume fraction of the intermetallic compound having a particle size of 0.1 to 1.0 μm is 1 to 5% as a material characteristic, and the conductivity is 30. 0 to 39.0% IACS, the tensile strength in the rolling direction of the base plate is 320 MPa or less, Strength after is a manufacturing method of a beverage can body for the aluminum alloy plate is at least 250MPa with yield strength in the rolling direction.

  The baking finish applied to the aluminum alloy plate for beverage can barrels of the present invention produced by the method for producing an aluminum alloy plate for beverage can barrels of the present invention described above is maintained at 180 to 220 ° C. for 5 to 30 minutes, or the highest Paint baking can be performed by holding at an ultimate temperature of 210 to 260 ° C. within 2 minutes.

  Moreover, in the manufacturing method of the aluminum alloy plate for beverage can bodies according to the present invention described above, cold rolling is performed at a total rolling rate of 70% or more, the final pass temperature is 130 ° C. or higher, and the other roll pass outlet temperatures are set. By performing the treatment under a temperature condition of 130 ° C. or less, the material structure can be recovered.

[Action]
The present inventors have examined in detail the cause of bottom wrinkle generation, and found that the bottom wrinkle can be improved by increasing the work hardenability of the material. Furthermore, this work hardenability is a finely dispersed intermetallic compound. The present invention has been found out that it can be improved by controlling the dispersion state.

  As described above, the aluminum alloy plate for beverage can bodies of the present invention has a volume fraction of an intermetallic compound having a particle size of 0.1 to 1.0 μm of 1 to 5% and an electrical conductivity of 30.0 to With 39.0% IACS, the tensile strength in the rolling direction of the base plate is set to 320 MPa or less, and the proof stress after baking is 250 MPa or more. Therefore, high strength and excellent bottom wrinkling properties can be realized. The aluminum alloy sheet of the present invention can be produced by regulating the homogenization treatment conditions in the ordinary aluminum alloy sheet production method, the time until start of hot rolling after furnace exit, the hot rolling conditions, and the cold rolling conditions. . This makes it possible to produce an aluminum can body material that has excellent bottom wrinkling properties and can have a high can body strength, and can be used for reducing the thickness of the aluminum can body and reducing the diameter of the can lid. .

The reasons for limiting the alloy composition will be described below with respect to the aluminum alloy plate for beverage can bodies of the present invention.
[Si component range: 0.10 to 0.25%]
Si causes phase transformation in the Al—Mn—Fe intermetallic compound in the homogenization treatment, and contributes to the formation of a high hardness Al—Mn—Fe—Si intermetallic compound having a solid lubricating action. As a result, a sufficient die screening effect is obtained, and the problem of seizure to the die during molding is prevented. The component range is 0.1 to 0.25%. If it is less than 0.1%, the intermetallic compound is not sufficiently formed, and seizure defects are likely to occur. If it exceeds 0.25%, the volume fraction of the intermetallic compound having a particle diameter of 0.1 to 1.0 μm is formed more than specified in the present invention, so that the bottom wrinkle property is lowered and the solid solution amount of the solute is reduced. However, the effect of increasing the strength of the can body cannot be obtained sufficiently. A desirable content is 0.18 to 0.22 wt%.

[Mn component range: 0.5 to 1.5%]
Mn is an element effective in improving can barrel strength and DI moldability, and forms a high-hardness intermetallic compound (Al-Mn-Fe-Si system) having a solid lubricating action as described above, thereby providing a die screening effect. It is an element necessary for obtaining. The component range is 0.5 to 1.5%. If it is less than 0.5%, the effect cannot be sufficiently obtained, and a problem that the aluminum alloy plate adheres to the die die due to insufficient lubrication occurs. Furthermore, since the intermetallic compound is not sufficiently formed, the can body strength is not improved. On the other hand, if the content is 1.5% or more, the material strength becomes too high, and thus DI moldability is impaired, and the volume fraction of the intermetallic compound having a particle size of 0.1 to 1.0 μm is more than specified in the present invention. Since it is formed, the bottom wrinkle property is lowered. A desirable content is 0.8 to 1.2 wt%.

[Mg component range: 0.8 to 1.5%]
Similar to Mn, Mg is an element that contributes to improving the strength of the can body, and is effective in increasing the strength of the bottom portion and improving work hardening. Its component range is set to 0.8-1.5%. If it is less than 0.8%, it is difficult to sufficiently obtain the required strength. Further, since sufficient work hardening does not occur at the time of molding, bottom wrinkles are likely to occur. Further, if the content exceeds 1.5%, the strength becomes too high, so that the frequency of occurrence of can barrel breakage and cracking increases during DI molding, thereby impairing moldability. A desirable content is 1.0 to 1.4 wt%.

[Fe component range: 0.35 to 0.5%]
Fe, like Mn and Mg, is an element that contributes to improving the strength of the can body, and also produces hard Al—Mn—Fe (—Si) -based intermetallic compounds having solid lubricating action including Mn. While promoting, the distribution state is made uniform and the moldability is improved. The component range is 0.35 to 0.5%. If it is less than 0.35%, it is difficult to impart sufficient strength, and further, an intermetallic compound necessary for preventing adhesion to a die is not sufficiently formed. If it exceeds 0.5%, the strength becomes too high, and the moldability is lowered.

[Cu component range: 0.1 to 0.3%]
Cu is an element that contributes to improving the strength of the can body by its own solid solution, and is an element that contributes to improving the strength by precipitation hardening of Al-Cu-Mg-based precipitates in the coating baking process during can making. . Thereby, the strength of the can body, particularly the strength of the bottom portion can be improved. The component range is 0.1 to 0.3%. If the content is less than 0.1%, sufficient material strength cannot be obtained. If the content exceeds 0.3%, the strength becomes too high. Is damaged.

[Inevitable impurities]
In aluminum alloy plates for beverage can bodies, a small amount of Ti and B is often added to refine crystal grains. The Ti content is limited to 0.1% or less, preferably 0.005% or more and 0.05% or less. If the Ti content is less than 0.005%, the effect of crystal grain refining cannot be sufficiently obtained. If the Ti content exceeds 0.05%, a large Al-Ti intermetallic compound tends to be produced. If it exceeds 1%, the tendency to generate a huge intermetallic compound of Al-Ti system increases, and cracks and pinholes are generated during the forming process, thereby reducing the formability.

  B has an effect of promoting crystal grain refinement. The B content is limited to 0.1% or less, preferably 0.001% or more and 0.01% or less. If the content is less than 0.001%, the effect cannot be sufficiently obtained. If the content exceeds 0.01%, a Ti-B giant intermetallic compound tends to be generated. The tendency to form a large -B-based intermetallic compound increases, and cracks and pinholes are likely to occur during molding. As other inevitable impurities, if Zn is 0.3% or less, Cr is 0.3% or less, Zr is 0.1% or less, and V is 0.1% or less, the effect of the present invention is not impaired. Is acceptable.

Next, the manufacturing method of the aluminum alloy plate of this invention is demonstrated.
First, an aluminum alloy having the alloy composition of the present invention is cast into a slab (plate ingot) by a water-cooled continuous casting method. The slab is homogenized. In the present invention, the homogenization temperature is regulated to 550 to 620 ° C. If it is less than 550 ° C., a sufficient homogenizing effect cannot be obtained, and segregation of the solute distribution is not sufficiently eliminated, so that the DI moldability is lowered. Furthermore, since a large number of intermetallic compounds having a particle size of 0.1 to 1.0 μm are distributed, the volume fraction is outside the specified value of the present invention. If it exceeds 620 ° C., the cast surface is swollen, and further, the eutectic portion is locally melted, so that the surface quality is remarkably deteriorated.

  As for the homogenization time, the effect is not sufficient unless it is maintained for 1 hour or longer, and a certain amount of time is required. In view of the homogenization effect and productivity, 3 to 12 hours is desirable, and 5 to 10 hours is appropriate. If the homogenization treatment is 550 ° C. or less or less than 1 hour, a sufficient homogenization effect cannot be obtained, and if it exceeds 620 ° C., the casting surface is swollen and the eutectic part is melted.

  Hot rolling is performed after the homogenization treatment. At that time, either a process of performing hot rolling as it is without reheating after the homogenization process or a process of performing reheating and hot rolling after being cooled to room temperature may be used.

  Furthermore, in order to adjust the distribution state of the intermetallic compound, the time from the start of the furnace to the start of hot rolling is regulated within 30 minutes. If it is 30 minutes or longer, an excessive amount of intermetallic compounds having a particle size of 0.1 to 1.0 μm is formed during that period, and the volume fraction falls outside the specified value of the present invention.

  The hot rolling start temperature is preferably 400 to 550 ° C, more preferably 450 to 550 ° C. If it is less than 450 ° C., sufficient rolling processability cannot be obtained, so there is a concern that cracks may occur at the edge of the sheet width, and if it is 400 ° C. or less, the hot rolling end temperature is lowered, so Since sufficient crystal grains are not generated, rolling cracks occur at the plate width edge portion. When the temperature exceeds 550 ° C., the DI formability deteriorates due to surface oxidation of the hot rolled plate or coarsening of recrystallized grains.

  The hot rolling end temperature is specified at 250 to 350 ° C. If it is 250 degrees C or less, it cannot be made into a recrystallized state, but the intensity | strength of a final board will raise remarkably and DI moldability will fall. On the other hand, in the case of 350 ° C. or higher, transition elements such as Mn are likely to be precipitated, so that the volume fraction of the intermetallic compound of the present invention is not specified.

  In the present invention, the thickness of the hot-rolled sheet is regulated to 2.5 mm or less, particularly 1.5 to 2.5 mm. When the plate thickness exceeds 2.5 mm, the cold rolling rate increases, the material strength increases, and the DI moldability decreases. On the other hand, if the thickness is less than 1.5 mm, the hot-rolled sheet is likely to be seized or rough, and the thickness profile is further deteriorated.

Cold rolling is performed after hot rolling. The exit side temperature of the final cold rolling is 130 ° C. or more, preferably 200 ° C. or less, and the exit side temperature of the other rolling passes is 130 ° C. or less, preferably 110 ° C. or less.
As described above, in the present invention, the material temperature is controlled by controlling the base plate strength that is excessively increased by reducing the processing dislocation density generated by the cold rolling in the middle pass by setting the outlet temperature of the final cold rolling to 130 ° C. or higher. Contributes to the improvement of bottom wrinkle.

  On the other hand, the exit side temperature of the intermediate pass rolling is 130 ° C. or lower, preferably 110 ° C. or lower, so that Al—Cu—Mg-based precipitates and Al—Cu—Mg—Si generated during cold rolling are used. This contributes to reducing the amount of system precipitates produced. As a result, dislocation localization starting from precipitates is less likely to occur during molding, so that local work softening due to dynamic recovery is suppressed and bottom wrinkle properties are improved. The total rolling reduction of cold rolling is 70% or more. If it is less than 70%, the pressure strength is insufficient. The total rolling rate of this cold rolling is preferably 90% or less. If it exceeds 90%, the strength of the final plate is remarkably increased and the DI moldability is lowered.

  Next, regarding the aluminum alloy plate for beverage can bodies of the present invention, the distribution state of the intermetallic compound (particle diameter, volume fraction) and the reason for limiting the conductivity will be shown.

  The structure | tissue which has the intermetallic compound characterized by this invention is obtained by an appropriate setting of an above-described alloy composition and a manufacturing process. An intermetallic compound having a particle diameter of 0.1 to 1.0 μm and a volume fraction of 1 to 5% specified in the present invention has an important influence on material strength and bottom wrinkle property. If the volume fraction of the intermetallic compound having a particle size of 0.1 to 1.0 μm exceeds 5%, dislocations are likely to be localized during the forming process, and work curability is lowered, so that bottom wrinkles are generated. It becomes easy to do. On the other hand, when the volume fraction is 1% or less, the effect of precipitation hardening cannot be sufficiently obtained, and the can body strength is not improved.

  For conductivity, the range is restricted to 30.0-39.0% IACS. The conductivity is a characteristic value that correlates with the amount of the solid solution element in the material. When the solute element is dissolved in the material, an effect of improving the can body strength by solid solution hardening can be obtained. If it exceeds 39.0% IACS, the amount of solid solution elements is small, so that the effect cannot be sufficiently obtained and the strength of the can body is not improved. On the other hand, if it is less than 30.0% IACS, the moldability deteriorates due to excessive solid solution curing.

Next, the reasons for limiting the tensile strength of the base plate of the aluminum alloy plate of the present invention and the yield strength after baking are described.
The tensile strength of the base plate is set to 320 MPa or less. If it exceeds 320 MPa, the deformation resistance of the material increases during molding, so the frequency of occurrence of cracks increases during ironing. The yield strength after baking is set to 250 MPa or more. When the pressure is less than 250 MPa, the pressure resistance is insufficient, and when the contents are filled as an aluminum can, the strength that can withstand changes in internal pressure cannot be maintained.

The present invention will be specifically described below based on examples.
The aluminum alloy of the present invention having the alloy components shown in Table 1 was melt cast by a conventional method to obtain a slab (plate ingot) having a thickness of 500 mm. The slab is chamfered to a thickness of 490 mm, homogenized at 600 ° C. for 6 hours, cooled to room temperature, and then reheated to the hot rolling start temperature. The time from the start of the furnace to the start of hot rolling is 20 minutes. Next, hot rolling is performed at a rolling start temperature of 490 ° C. and a rolling end temperature of 320 ° C. to obtain a hot-rolled sheet having a thickness of 2.2 mm, which is wound around a coil and cooled to room temperature. For hot rolling, rough rolling was performed with a single mill reverse type rolling mill, and a four-stand tandem rolling mill was used for finish rolling. Next, cold rolling is performed to produce an aluminum alloy plate for beverage can bodies having a thickness of 0.3 mm. In cold rolling, the total rolling rate of 3 passes is 86%.

(Comparative Example 1)
An aluminum alloy plate was produced by the same method as in Example 1 except that the alloy composition was outside the specified value of the present invention.

  Table 1 shows the alloy compositions of Example 1 and Comparative Example 1 of the present invention.

  For each aluminum alloy produced in Example 1 and Comparative Example 1, (1) mechanical properties, (2) conductivity, (3) particle size and volume fraction of intermetallic compound, (4) DI moldability, (5) Can bottom moldability (bottom wrinkle property) and (6) pressure strength were evaluated.

(1) The mechanical properties were measured by measuring the tensile strength of the base plate in the rolling direction of the manufactured aluminum alloy plate and the yield strength after baking.
Empty baking is the assumption of paint baking conditions at the time of can-making, and was performed at 205 ° C. for 10 minutes. With respect to the tensile strength of the base plate, 320 MPa or less was evaluated as acceptable (within the specified value of the present invention), and the yield strength after baking was determined to be acceptable at 250 MPa or more.
(2) The conductivity was measured by an eddy current method after being kept at a constant temperature in a constant temperature room at 20 ° C.
(3) The particle size and volume fraction of the intermetallic compound were determined by using a transmission electron microscope for a sample from which dislocation was removed by water quenching after heating in a salt bath at 450 ° C. for 20 seconds. The volume fraction of the intermetallic compound of 0.1 to 1.0 μm was determined. Note that the intermetallic compound was assumed to be a sphere, and the sample thickness was determined by equal thickness interference fringes.

(4) DI moldability is DI molded into a can body for a general beverage (inner diameter 66 mmΦ, sidewall plate thickness 100 μm, sidewall tip plate thickness 150 μm), and is a can of 10,000 cans. Continuous without cracking or breaking. What was able to be made can be judged as good (◯), and those with cracks and fractures were judged as bad (x).
(5) For bottom wrinkle, the cup is squeezed from the blank, and then the re-drawn can (blank diameter: 140 mmΦ, cup diameter: 87 mmΦ, redrawable diameter: 66 mmΦ) Measurements were made and evaluated at the maximum amplitude. A maximum amplitude of 180 μm or less was judged as good (◯), and 180 μm or more was judged as bad (×).
(6) With regard to the pressure strength, after DI molding, baking (205 ° C. × 10 minutes) was performed, and the pressure at which the can bottom dome was reversed by applying air pressure to the inside of the can body was measured. A reversal pressure of 650 kPa or higher was judged as good (◯), and a reversal pressure of 650 kPa or lower was judged as defective (x). These survey results are shown in Table 2. Table 2 shows various characteristic evaluations of the aluminum alloys manufactured in Example 1 and Comparative Example 1.

  As apparent from Table 2, the sample No. of Example 1 in which the alloy composition is within the specified range of the present invention and the manufacturing conditions satisfy the present invention. 1 (alloy No. A), sample no. 2 (Alloy No. B), Sample No. All the aluminum alloy plates of No. 3 (alloy No. C) were excellent in bottom wrinkle properties and good properties (DI moldability, pressure strength, mechanical properties) required for beverage cans.

On the other hand, Sample No. of Comparative Example 1 whose alloy composition is outside the scope of the present invention. Since the aluminum alloy plate of No. 4 (alloy No. D) has a large amount of Mg, the tensile strength of the base plate increased, the DI formability decreased, and ironing cracks occurred.
Sample No. Since the aluminum alloy plate of No. 5 (Alloy No. E) has a small amount of Mg, the yield strength after baking was outside the scope of the present invention, resulting in poor pressure strength.

Sample No. 6 (Alloy No. F) aluminum alloy plate has a large amount of Mn, so the tensile strength of the base plate increases, and a coarse intermetallic compound is formed. did. Furthermore, the volume fraction of the intermetallic compound having a particle size of 0.1 to 1.0 μm was outside the specified value of the present invention, and bottom wrinkles were observed.
Sample No. Since the aluminum alloy plate of No. 7 (Alloy No. G) had a small amount of Mn, the amount of crystallized material having a solid lubricating action was reduced, the ironing die was baked, the surface of the can was rough, and the molding was defective. Furthermore, the proof stress after baking was out of the scope of the present invention, and the pressure resistance decreased.

Sample No. The aluminum alloy plate of No. 8 (alloy No. H) has a large amount of Si, so the amount of solute is reduced and the effect of increasing the strength of the can body after baking is not obtained by solid solution hardening, resulting in a decrease in pressure resistance. did.
Sample No. 9 (Alloy No. I) had a small amount of Si, so the amount of crystallized material having a solid lubricating action was reduced, the ironing die was baked, the surface of the can was rough, and the molding was defective.

Sample No. Since the aluminum alloy plate of No. 10 (alloy No. J) has a small amount of Cu, the yield strength after baking was out of the scope of the present invention, resulting in poor pressure strength.
Sample No. Since the aluminum alloy plate of No. 11 (alloy No. K) has a large amount of Cu, the tensile strength of the base plate increased and the DI moldability decreased.

  The aluminum alloy of (alloy No. A) of the present invention composition shown in Table 1 is melt cast by a conventional method to form a plate-like ingot (slab) having a thickness of 500 mm, which is chamfered to a thickness of 490 mm, and then homogenized. Processing and hot rolling. Next, it cold-rolled and manufactured the aluminum alloy plate for drink can bodies of thickness 0.3mm variously within the regulation value of this invention.

(Comparative example 2) The aluminum alloy plate was manufactured by the same method as Example 2 except having made manufacturing conditions outside the regulation value of the present invention. About each aluminum alloy plate obtained in Example 2 or Comparative Example 2, various characteristics were investigated by the same method as in Example 1, and the quality was judged. The results are shown in Tables 3 and 4. Table 3 shows the aluminum alloy sheet manufacturing conditions of Example 2 and Comparative Example 2 of the present invention.

  Table 4 shows various characteristics evaluations of the aluminum alloys manufactured in Example 2 and Comparative Example 2 of the present invention.

  As is apparent from Table 4, the aluminum alloy of Example 2 of the present invention (Sample No. 12, Sample No. 13, Sample No. 14, Sample No. 15, Sample No. 16, Sample No. 17, Sample No. 17). No. 18) had good bottom wrinkle properties, and the particle diameter and volume fraction of the intermetallic compound, the electrical conductivity, the tensile strength of the base plate, and the proof strength after baking were values that satisfied the conditions of the present invention.

  On the other hand, sample No. which is a comparative example. In No. 19 aluminum alloy sheet, since the time until the start of hot rolling after furnace discharge was 30 minutes or more, bottom wrinkles were generated due to the formation of intermetallic compounds.

Sample No. Since the aluminum alloy plate No. 20 had a low homogenization temperature, segregation was not sufficiently eliminated and DI formability was lowered. Furthermore, bottom wrinkles were observed due to the formation of intermetallic compounds.
Sample No. Since the aluminum alloy plate No. 21 had a high hot rolling start temperature, the iron formability was lowered.
Sample No. Since the aluminum alloy plate No. 22 had a low hot rolling finish temperature, it was not recrystallized and its DI formability was lowered.

Sample No. 23 and sample no. The aluminum alloy sheet No. 24 had a high exit temperature in the first or second pass of cold rolling, and bottom wrinkles were generated due to excessive formation of intermetallic compounds.
Sample No. The 25 aluminum alloy sheet had a low exit side temperature in the final cold rolling, and the bottom wrinkle property was lowered.
Sample No. The 26 aluminum alloy sheet had a low total rolling rate, so the yield strength after baking was reduced and the pressure resistance was reduced.

  The present invention relates to an aluminum alloy plate used as a can body material for various beverage cans such as carbonated beverages, beer and soft drinks, and has an excellent bottom wrinkle property and can provide a high can body strength. It can be applied as a plate and its manufacturing method.

It is sectional drawing which shows typically the site | part (can bottom chime part) where a bottom wrinkle generate | occur | produces.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Beverage can body, 2 ... Can side wall, 3 ... Can bottom chime part, 4 ... Can bottom grounding part

Claims (5)

  Si: 0.10 to 0.25% (mass%, the same applies hereinafter), Mn: 0.5 to 1.5%, Mg: 0.8 to 1.5%, Fe: 0.35 to 0.5% Cu: 0.1 to 0.3%, Ti: 0.1% or less, B: 0.1% or less, the balance is an aluminum alloy plate made of Al and inevitable impurities, The volume fraction of the intermetallic compound having a particle size of 0.1 to 1.0 μm is 1 to 5%, the conductivity is 30.0 to 39.0% IACS, and the tensile strength in the rolling direction of the base plate is 320 MPa. An aluminum alloy plate for a beverage can body, characterized in that the strength after baking is at least 250 MPa in terms of proof stress in the rolling direction.   The aluminum alloy plate for beverage can bodies according to claim 1, wherein the baking is performed by holding the coating baking at 180 to 220 ° C for 5 to 30 minutes, or holding the maximum baking temperature at 210 to 260 ° C within 2 minutes.   Si: 0.10 to 0.25%, Mn: 0.5 to 1.5%, Mg: 0.8 to 1.5%, Fe: 0.35 to 0.5%, Cu: 0.1 An aluminum alloy ingot containing 0.3%, Ti: 0.1% or less, B: 0.1% or less, the balance being Al and inevitable impurities is manufactured, and the aluminum alloy ingot is face-cut. Then, a homogenization treatment is performed at a temperature of 550 to 620 ° C., and after the furnace is discharged, the time until the start of hot rolling is within 30 minutes, and then the hot rolling is performed at a rolling end temperature of 250 to 350 ° C. As a material property, the volume fraction of the intermetallic compound having a particle size of 0.1 to 1.0 μm is 1 to 5%, the conductivity is 30.0 to 39.0% IACS, and the rolling direction of the base plate The tensile strength at 320 is 320 MPa or less, and the strength after baking is 250 MPa or more as the proof stress in the rolling direction. Method for producing a beverage can body for an aluminum alloy sheet, wherein the door.   4. Production of aluminum alloy sheet for beverage can body according to claim 3, wherein the paint baking is performed by holding at 180-220 [deg.] C. for 5-30 minutes or at a maximum temperature of 210-260 [deg.] C. for 2 minutes. Method.   Cold rolling is performed at a total rolling ratio of 70% or more under a temperature condition in which the outlet temperature of the final pass is 130 ° C. or higher and the outlet temperature of the other rolling passes is 130 ° C. or lower. The manufacturing method of the aluminum alloy plate for drink can bodies of Claim 3 or Claim 4 to perform.

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