JP2007169744A - Aluminum alloy sheet for aluminum bottle can barrel having excellent can roundness and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aluminum alloy sheet required for producing an aluminum bottle can barrel in which defects in necking forming are reduced, and can shape (roundness) after necking forming is satisfactory. <P>SOLUTION: The aspect ratio (the length in the rolling direction)/(the length in the sheet thickness direction) in the crystal grains of an Al-Mn-Mg-Cu alloy sheet having a specified composition is controlled to 10 to 30, the area ratio of intermetallic compounds with a size satisfying a diameter equivalent to a circle of 0.1 to <0.3 μm is controlled to 0.3 to 0.8%, also, the area ratio of intermetallic compounds with a size satisfying a diameter equivalent to a circle of ≥3 μm is controlled to 0.3 to 0.5%, and, the anisotropy in material strength in the case a test piece is extracted from the side wall part of a bottle-shaped formed body is controlled to ≤5%. In its production method, a cast ingot is subjected to homogenizing treatment, and thereafter, the temperature conditions of hot rolling, the spraying conditions of rolling oil and the like are controlled to specified ranges. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an aluminum alloy plate for an aluminum bottle can body in which a can body portion is formed by DI processing (Draw drawing + Ironing ironing) and a drinking mouth portion is formed by necking a can opening portion. In addition, the bottle can body, which is the subject, is equipped with a screw part for fitting with the cap body serving as a lid, so that the consumer does not feel uncomfortable when drinking the beverage body that is the contents. Curled.

  In the past, inventions aimed at improving the roundness of cans in aluminum DI cans have been made, but differ from the contents of the present invention for the following reasons.

  Patent Documents 1 and 2 stipulate the upper limit of the tensile strength anisotropy in the plate surface and the absolute value of the ear ratio in order to improve the can roundness of the DI can. Both are effective measures to improve the roundness of the can, but the production method of the aluminum alloy sheet requires a combination of provision of intermediate annealing between cold rolling passes and cold rolling in different directions, It is disadvantageous industrially.

  Patent Document 3 describes a method for producing a DI molded body in which heat treatment is applied to the cup after drawing, but applying the heat treatment to the conventional molding process significantly impairs productivity.

Patent Document 4 stipulates that the tensile strength anisotropy in the plate surface is within 1.5 kgf / mm ² in order to improve the roundness of the can in the DI can. In order to reduce the final cold rolling rate and the crystal grain size, it is necessary to apply a relatively high temperature annealing treatment between the cold rolling passes, which is different from the present invention which does not require an intermediate heat treatment.

  Patent Document 5 stipulates that when an aluminum alloy plate is heat-treated at 230 to 270 ° C. for 20 minutes, the tensile strength change ΔTS before and after the heat treatment is (1.1 × T-230) or less. ing. The object of the present invention is to suppress changes in the shape of the can due to baking treatment for paint baking of the can, which is different from the present invention.

  Although there is an invention related to the material for aluminum DI cans, although not directly related to the roundness, it differs from the contents of the present invention for the following reasons.

  Patent Document 6 discloses that a Q phase (Al) of 100 nm or less that promotes the generation of 100-200 nm Al—Mg—Cu-based precipitates that contribute to an increase in strength, does not contribute to an increase in strength, and significantly lowers iron moldability. For the purpose of suppressing precipitates of (Cu-Mg-Si system), a method for producing an aluminum plate is defined. The strength anisotropy, which is the object of the present invention, is particularly affected by the occupation density of 100-200 nm Al—Mg—Cu-based precipitates, but differs in that control by applying an intermediate annealing step is not performed.

  In Patent Document 7, in order to improve the iron moldability, the lower limit of the density of a crystallized substance having a size of 5 μm or more existing on the aluminum surface is defined together with other characteristics. This is aimed at the die screening effect at the time of ironing forming, and the purpose is different, and since it is necessary to impart two annealings in the middle of cold rolling, it is not industrially preferable.

Japanese Patent Laid-Open No. 02-092220 Japanese Patent Laid-Open No. 02-092421 Japanese Patent Laid-Open No. 04-172138 Japanese Patent Laid-Open No. 03-146632 JP 2003-277865 A Japanese Patent Laid-Open No. 06-002089 Japanese Patent Laid-Open No. 06-271968

  The aluminum bottle can body is generally manufactured as follows. An aluminum alloy plate is punched into a circular shape and drawn into a cylindrical shape. After thinning the side wall of the cylindrical container by DI molding and securing the height of the can so as to obtain the required capacity, the inner and outer surfaces of the can are painted through a washing and drying process. The diameter of the opening of the painted can is reduced by necking, and threading and curling are performed.

  If the shape of the opening is distorted by the necking molding described above, defective loading into the mold may occur during threading or curl processing in the next process, or the distortion of the shape may be exaggerated by processing. The aluminum bottle can is finally filled with the contents and needs to be fitted with the cap lid, but if the shape of the screw or curl near the opening is distorted, the seal with the cap is secured. May be insufficient, or the torque required to open the sealed cap may be excessive.

  An object of the present invention is to provide an aluminum alloy plate which is necessary for reducing defects in necking molding and for producing an aluminum bottle can body having a good can shape (roundness) after necking molding. .

  The present invention provides an aspect ratio of crystal grains of an aluminum alloy having a specific composition, an area ratio of an intermetallic compound having a circle equivalent diameter of 0.1 μm or more and less than 0.3 μm and an intermetallic compound having a circle equivalent diameter of 3 μm or more. This is based on the knowledge that each of the above can be solved within the specific range. Moreover, it is based on the knowledge that such a rolled sheet can be manufactured by controlling the temperature conditions of hot rolling, spraying conditions of rolling oil, and the like within a specific range.

    That is, as described in claim 1, Mg: 0.8-1.2%, Mn: 0.7-1.5%, Cu: 0.10-0.25%, Si: 0.1-0. 3%, Fe: 0.1 to 0.3%, balance Al and inevitable impurities, aspect ratio of crystal grains in cross section parallel to rolling direction (length in rolling direction) / (length in plate thickness direction) And the intermetallic compound having a circle equivalent diameter of 0.1 μm or more and less than 0.3 μm is distributed in an area ratio of 0.3 to 0.8% in a cross section parallel to the rolling direction, and For an aluminum alloy sheet in which an intermetallic compound having a circle-equivalent diameter of 3 μm or more is distributed in an area ratio of 0.3 to 0.5% in a cross section parallel to the rolling direction, a drawing ratio of 1.5 to 2. After drawing at 0, redrawing with a drawing ratio of 1.1 to 1.3 and a plate thickness reduction rate of 6 on the side wall After three or four steps of ironing are applied to make up to 70%, baking is performed at a baking temperature of 200 ° C. for 15 minutes, and then a 12-15% squeezing is performed near the opening of the can. An aluminum alloy plate for can bottles with excellent can roundness, characterized in that the material strength anisotropy is 5% or less when a specimen is taken from the side wall of the molded body necked at a rate. is there.

Furthermore, the manufacturing method is as described in claim 2, the alloy ingot having the above composition is homogenized at 570 to 620 ° C. for 4 to 48 hours, cooled to 450 to 550 ° C., and then hot rough rolled. Starting, a hot rough rolled sheet having a rising temperature of 400 to 470 ° C. is obtained. When this hot rough rolled sheet is rolled by a tandem hot finish rolling mill, a rolling roll and / or a rolling roll is obtained. The total amount of rolling oil sprayed on the plate is 150 to 350 liters / minute per 1 m of the plate width,
The total rolling reduction of hot finish rolling is 88 to 93%, the rolling speed is 270 m / min or more, and the coil side surface temperature immediately after coiling is 310 to 340 ° C. By performing the cold rolling so that the coil rolling temperature is 80 to 150 ° C. immediately after winding after the cold rolling is finished and the coil rolling temperature is 75 to 87% in 2 to 4 passes. The aspect ratio of the crystal grains in the cross section parallel to the rolling direction (length in the rolling direction) / (length in the plate thickness direction) is 10 to 30, and the circle equivalent diameter is 0.1 or more and less than 0.3 μm. An intermetallic compound is distributed in an area ratio of 0.3 to 0.8% in a cross section parallel to the rolling direction, and an intermetallic compound having a circle-equivalent diameter of 3 μm or more has an area ratio of 0.00 in a cross section parallel to the rolling direction. The distribution is 3 to 0.5%. The is an excellent method for producing the aluminum bottle can barrel aluminum alloy strip for cans roundness characterized.

  According to the present invention, defects in necking molding of an aluminum bottle can body can be reduced, and an aluminum bottle can body having a good can shape (roundness) after necking molding can be created.

  The reason for the action and range limitation of the alloy components in the present invention will be described.

  Mg: Addition amount is 0.8 to 1.2%. Mg contributes to strength improvement by solid solution hardening. It is also a constituent element of precipitates that contribute to strength improvement during cold rolling and baking. If it is less than 0.8%, these effects are insufficient, and if it exceeds 1.2%, work hardening during rolling or forming becomes large, and the anisotropy of the material becomes large.

  Mn: Addition amount is set to 0.7 to 1.5%. Mn is an element necessary for improving the strength and forming an Al (Fe, Mn) Si-based compound (α phase). The α phase has the function of preventing seizure on the die during ironing and is essential for this application. If it is less than 0.7%, the effect is insufficient, and if it exceeds 1.5%, the Al—Mn—Fe coarse crystallized product increases and the iron moldability is impaired.

  Cu: Addition amount is set to 0.10 to 0.25%. Cu is necessary for increasing strength and improving heat resistance due to Al-Mg-Cu precipitation during cold rolling and baking. If it is less than 0.10%, the effect is small, and if it exceeds 0.25%, the density of Al—Mg—Cu-based precipitates increases and the material anisotropy increases.

  Si: Addition amount is 0.1 to 0.3%. Si is an element necessary for forming the aforementioned α phase. Further, since the Mn solid solution amount changes depending on the Si addition amount, it is also effective as a means for controlling the Mn solid solution amount. If Si is less than 0.1%, it is impossible to obtain an α-phase distribution sufficient to prevent baking on the die. If it exceeds 0.3%, the solid solubility limit of Mn decreases, and the size and distribution density of Al-Mn-Fe (-Si) -based crystallized crystals become too large. Cracks will occur as a starting point.

  Fe: Addition amount is 0.1 to 0.3%. Fe is an element necessary for the formation of the α phase, like Si and Mn. Further, similarly to Si, the Mn solid solution amount can be controlled by the addition amount. If it is less than 0.1%, the effect of preventing seizure to the die is insufficient, and if it exceeds 0.3%, a coarse crystallized product is formed, and ironing formability is impaired.

  In addition to the above elements, basically, Al and inevitable impurities may be used.

In particular, Ti and B are elements for uniformly refining ingot crystal grains and are often added for this purpose. However, when the content exceeds 0.1% and 0.001%, coarse crystallized substances are formed. Forming and ironing formability are reduced, and pinholes on the side wall of the can are easily generated.

  The crystal grain aspect ratio (length in the rolling direction) / (length in the plate thickness direction) in the cross section parallel to the rolling direction of the aluminum alloy plate = 10-30. As in the present invention, in a manufacturing method that does not include an annealing step for the purpose of recrystallization after hot rolling, the shape and size of the crystal grains obtained during the final recrystallization during hot rolling are hot. The aspect ratio of the crystal grains changes depending on the amount of cold rolling reduction after rolling. When the crystal grain aspect ratio exceeds 30, the amount of cold rolling becomes excessively large, and the strength anisotropy of the can opening when formed into the aluminum alloy plate and the can body becomes large. Further, if the crystal grain aspect ratio is less than 10, the amount of cold rolling is insufficient, so that the strength required for the can cannot be obtained.

  The distribution of the intermetallic compound having an equivalent circle diameter of 0.1 μm or more and less than 0.3 μm existing in the aluminum alloy sheet is such that the area ratio is 0.3 to 0.8% in the cross section parallel to the rolling direction. Control. An intermetallic compound having an equivalent circle diameter of 0.1 μm or more and less than 0.3 μm is obtained by dividing the crystallized product generated during casting solidification into a temperature range from hot rolling to cold rolling. Are deposited. An intermetallic compound of this size contributes to imparting strength to the aluminum alloy sheet by increasing the degree of accumulation of dislocations in cold rolling. However, the excessive presence of intermetallic compounds increases the strength difference between the rolling direction and the other direction, which affects the strength anisotropy. When the distribution of the intermetallic compound is more than 0.8% in a cross section parallel to the rolling direction, the strength anisotropy after cold rolling or can forming becomes too high, and 0.3% If it is less than this, the strength required for the can cannot be obtained.

  Further, the distribution of the intermetallic compound having an equivalent circle diameter of 3 μm or more is set to an area ratio of 0.3 to 0.5% in a cross section parallel to the rolling direction. An intermetallic compound having a size of 3 μm or more corresponds to a crystallized product generated during casting solidification, which remains in the material without being finely divided even when rolled. Al-Mn-Fe-based and Al-Mn-Fe (-Si) -based crystallized substances are applicable, but especially Al-Mn-Fe (-Si) -based crystallized substances are very hard and are used during grinding. It acts like a grain to prevent the material from being baked on the ironing mold and to increase the gloss of the surface of the aluminum can. If the intermetallic compound with a thickness of 3 μm or more is less than 0.3%, the above-mentioned effects cannot be obtained. If it exceeds 0.5%, the material deformation resistance during ironing increases, and the same crystal The material breaks frequently from the starting material.

  The aluminum alloy plate satisfying the above requirements is subjected to drawing at a drawing ratio of 1.5 to 2.0, followed by redrawing with a drawing ratio of 1.1 to 1.3 and a reduction in thickness of the side wall. After the can container which has been continuously subjected to the three-stage or four-stage iron forming so as to be 60 to 70% is baked at a baking temperature of 200 ° C. for 15 minutes, it is further placed near the opening of the can. The material strength anisotropy is 5% or less when a test piece is collected from the side wall of the molded article necked at a drawing ratio of ˜15%. If it exceeds 5%, the roundness of the cross-sectional shape parallel to the height direction of the can opening portion deteriorates, and a defect occurs in curl molding or threading molding as the next process.

  In the present invention, an aluminum alloy having the above alloy composition is made into an ingot by ordinary DC casting and manufactured by the following steps.

  After homogenizing at 570 to 620 ° C. for 4 to 48 hours, after furnace cooling to 450 to 550 ° C., hot rough rolling is started, and the hot rough rolled aluminum alloy sheet having a rising temperature of 400 to 470 ° C. Get. Next, when this hot rough rolled sheet is rolled with a tandem hot finish rolling mill, the rolling oil and / or rolling oil sprayed on the rolled sheet is totaled at 150 to 350 liters / minute per sheet width. The total rolling reduction of hot finish rolling is 88 to 93%, the rolling speed is 270 m / min or more, and the coil end face temperature immediately after coiling is 310 to 340 ° C., followed by intermediate heat treatment When the cold rolling is performed, the entire rolling rate is 75 to 87% in 2 to 4 passes, and the coil side surface temperature immediately after winding after the cold rolling is 80 to 150 ° C. Is cold rolled.

  The homogenization treatment is performed at 570 to 620 ° C. or lower for 4 to 48 hours. The purpose of the homogenization treatment is to homogenize the heterogeneous structure produced during casting and to stabilize the unstable phase. However, in the bottle can material as in the present invention, the Al—Fe · Mn system phase is changed to Al (Fe , Mn) Si transformation is important. When the Al (Fe, Mn) Si-based phase is appropriately dispersed, the material can be prevented from being burned into the die during ironing. If the homogeneous temperature is less than 570 ° C., the amount of transformation to α phase is not sufficient, and if it exceeds 620 ° C., there is a possibility of burning, which is not preferable. If the holding time is less than 4 hours, the homogenization effect of the entire ingot cannot be obtained. Even if the holding time is maintained for 48 hours or more, the effect is saturated, which is not industrially preferable.

  After the furnace is cooled to 450 to 550 ° C. after the homogenization treatment, hot rough rolling is started to obtain a hot rough rolled aluminum alloy sheet having a rising temperature of 400 to 470 ° C.

  When manufacturing in a process in which intermediate annealing is not performed after hot rolling as in the present invention, it is essential to realize recrystallization of the entire material at the end of hot finish rolling. Therefore, temperature management of materials from homogenization to hot finish rolling is important. If the temperature at the start of hot rough rolling is less than 450 ° C., recrystallization of the material after hot finish rolling cannot be achieved completely, no matter how the hot rolling conditions that are subsequently applied are changed. When it exceeds 550 degreeC, possibility that a material and a roll will raise | generate baking during hot rough rolling will become high.

  The rise temperature of hot rough rolling depends on the rolling time and atmosphere temperature of hot rough rolling, the rolling amount, and the oil temperature and jetting amount of rolling oil, but at less than 400 ° C, the temperature of the material after hot finish rolling is reduced. If the crystallization is insufficient and the hot rough rolling is performed so as to exceed 470 ° C., the rolling condition becomes too severe, and a defect such as pickup inclusion occurs on the material surface.

  When rolling with a tandem type hot finish rolling mill, the total rolling oil to be blown onto the rolling roll and / or the rolled sheet is 150 to 350 liters / minute per 1 m of the sheet width, and the total reduction ratio of the hot finish rolling. Is set to 88 to 93%, the rolling speed is set to 270 m / min or more, and the coil side surface temperature immediately after winding in a coil shape is set to 310 to 340 ° C.

  The coil temperature after being wound on the coil is the most important item for achieving recrystallization of the entire material. In addition to satisfying this temperature, the finish total rolling reduction, rolling speed, etc. should be controlled. To do. If the material is not sufficiently recrystallized, the strength anisotropy of the aluminum alloy sheet subjected to the subsequent cold rolling will increase. If the coil temperature is less than 310 ° C, recrystallization of the material is insufficient, and surface defects frequently occur under rolling conditions where the temperature exceeds 340 ° C. As described above, in order to achieve recrystallization in the entire aluminum alloy plate, it is necessary to perform processing of a certain amount or more and ensure that the material temperature after rolling is equal to or higher than the recrystallization temperature by processing heat generation of the material. . If the total rolling reduction of hot finish rolling is less than 88%, the processing rate is not sufficient, and thus the material temperature after hot finish rolling cannot reach the recrystallization temperature. If the processing rate exceeds 93%, the processing rate per step becomes too high, and the material surface may become defective. The rolling speed corresponds to the strain rate of the material, but if it is not 270 m / min or more, recrystallization of the material is not promoted, and even if recrystallized, coarse crystal grains may be formed. The upper limit is not particularly defined, but 400 m / min or less is preferable in order to prevent the plate from being cut due to excessive tension acting on the material.

  The hot rolling oil sprayed on the rolling roll and / or the rolled sheet is generally obtained by emulsifying a mineral oil base oil and an oily agent in water, and its purpose is for lubrication and cooling. . If the total amount of hot rolling oil exceeds 350 liters / minute per 1 m of the plate width, the aluminum alloy plate is excessively cooled, and a coil temperature of 310 to 340 ° C. after hot finish rolling cannot be secured. If it is less than 150 liters / minute, lubrication between the roll and the aluminum alloy plate becomes insufficient, and pick-up inclusion may occur frequently or the aluminum alloy plate may be baked on the roll.

  Cold rolling is performed so that the overall rolling rate is 75 to 87% and the coil side surface temperature immediately after winding is 120 to 150 ° C. in the number of rolling passes of 2 to 4 passes. Cold rolling is intended to impart strength by work hardening, but Al-Cu, Al-Mg, and Al-Mg-Cu-based precipitates are present in the temperature range at the end of rolling or at the end of rolling during cold rolling. In the subsequent cold rolling, dislocations accumulate around the precipitate, resulting in a phenomenon in which excessive strength and strength anisotropy deteriorate. When the rolling rate exceeds 87%, the strength anisotropy of the material becomes too high, and the roundness of the mouth portion of the bottle can deteriorates. If it is less than 75%, the strength required for the can cannot be obtained. In addition, although the number of rolling is 2 to 4 passes, the above rolling rate cannot be cold-rolled with 1 pass, and it is possible to roll with 5 passes or more, but the manufacturing time becomes excessive. Industrially unfavorable. When the coil side surface temperature immediately after winding exceeds 150 ° C., Al—Cu, Al—Mg, and Al—Mg—Cu based precipitates are excessively deposited, resulting in poor strength anisotropy. If rolling to less than 80 ° C., the rolling speed is abnormally slow, which is not industrially preferable.

Examples are shown below. The evaluation method of characteristics was performed as follows.
<Evaluation method>

-Measurement of crystal grain size of cross section of plate The cross section parallel to the rolling direction of the final plate (cross section with two sides in the rolling direction and the plate thickness direction) was mechanically / electropolished, and the crystal grain size was measured with an optical microscope. The length L1 in the rolling direction and the length L2 in the thickness direction of the crystal grains were measured to determine the aspect ratio (L1 / L2) of the crystal grains. The observation location was the center layer of the plate thickness of the plate cross section, and the average value of the aspect ratios measured at 30 locations was determined.

-Area ratio of intermetallic compound The cross section parallel to the rolling direction of the final plate (cross section with two sides in the rolling direction and the plate thickness direction) is mechanically polished, and the intermetallic compound is photographed with a transmission electron microscope / optical microscope. did. In order to derive the area ratio, the photographed image was binarized by an image analysis device, and was determined from the ratio of the area occupied by the second phase particles to the analysis visual field area. The analysis visual field area was 0.2 mm ² for an intermetallic compound having a circle equivalent diameter of 0.1 μm or more and less than 0.3 μm, and 5 mm ² for an intermetallic compound having a circle equivalent diameter of 3 μm or more.

・ Tensile test of can flange part Drawing is performed at a drawing ratio of 1.7, then redrawing with a drawing ratio of 1.2 and three-stage ironing so that the thickness reduction rate of the side wall part is 66%. After the cans were continuously baked at a baking temperature of 200 ° C for 15 minutes, necking was performed near the opening of the cans at a drawing ratio of 14%. did.
For cans after ironing (represented as “after DI” in the table), after baking (represented as “after baking” in the table), and after necking (represented as “after necking” in the table) A test piece for a tensile test was cut out at a size of 15 mm from the opening end in the can height direction and 80 mm in the circumferential direction of the can, and a tensile test was performed at a pulling speed of 20 mm / min to obtain a can side wall strength. In addition, each can was tested in three directions of 0 °, 45 °, and 90 ° from the rolling direction, and the strength anisotropy of the can side wall was determined from {(maximum value) − (minimum value) )} / (Average value in three directions). If the material strength after baking is less than 280 MPa as the strength required for the can body, it is judged as defective.

・ Roundness of the opening of the necking can The shape profile of the necking can at the position of 10 mm from the end of the can opening is measured at n = 10, and the radius of the outer circle and the inner circle when sandwiched between two concentric circles The difference was roundness, and the average value for 10 cans was roundness. When the roundness exceeds 0.3 mm, it is determined as defective.

An Al alloy having the alloy composition shown in Table 1 was melt cast by a conventional method to produce an ingot. Subsequently, after homogenization at 600 ° C. × 6 h, the furnace was cooled to 490 ° C. and immediately subjected to hot rough rolling. The rising temperature of hot rough rolling was 430 to 470 ° C. as measured with a radiation thermometer. Thereafter, the plate was conveyed by a drive table, and hot finish rolling was started 300 seconds after the hot rough rolling was completed. Hot finish rolling is performed with a four-stage tandem rolling mill, the total rolling reduction is 90%, the minimum rolling speed of the final product is 275 m / min, and the maximum rolling speed is 350 m / min. . Immediately before coiling, the temperature was controlled using a radiation thermometer, and the amount of hot rolling oil ejected was controlled. The amount of rolling oil used as a result was 200 to 300 liters / minute, and the material temperature immediately after coiling was 320 to 330 ° C. It was confirmed that the entire plate after hot rolling was completely recrystallized.
Thereafter, an aluminum plate was manufactured with 3 passes of cold rolling and a total reduction ratio of 85.8% without performing intermediate heat treatment (annealing). The coil temperature immediately after 3 cold rolling passes was 130 ° C.

An alloy within the composition range of the present invention has good ironing and necking can processability and good roundness at the opening of the necking can.
No. 7, 8, and 11 had a large amount of Si, Fe, and Mn, respectively, so that the distribution of intermetallic compounds with an equivalent circle diameter of 3 μm or more was excessive, and fractures occurred frequently during DI molding. No. 9 and 13, since Cu and Mg exceed the specified amount, the distribution of intermetallic compounds with an equivalent circle diameter of 0.1 μm or more and less than 0.3 μm becomes excessive, and the roundness at the opening of the necking can is increased. It was bad. No. Nos. 10, 12, and 14 had a small amount of Cu, Mn, and Mg, respectively, so that the side wall strength after baking was insufficient.

  An ingot was produced by melting and casting an Al alloy having an alloy composition 1 in Table 1 in a conventional manner. Then, the homogenization process, hot rolling, and cold rolling were implemented on the conditions of Table 2, and the aluminum alloy plate was manufactured.

  Table 2 shows the results of the examples. In the production conditions A and B of the present invention, the crystal grain aspect ratio of the cross section of the plate and the distribution of intermetallic compounds are within the present invention, and the results of good DI moldability and roundness of the can are obtained.

In C, since the homogenization temperature was low, the distribution of the crystallized product was too large, and although no fracture occurred during DI molding, vertical streaks were observed on the side wall of the can cylinder. D is the case where the time from the end of the homogenization treatment to the start of hot rough rolling has become long, but the coil temperature after hot finish rolling does not reach the required temperature, and the material is sufficiently recrystallized. It was not converted. E and F are cases where the amount of hot finish rolling oil used is small and large, respectively, but in the former case, roundness of the can deteriorated due to excess of precipitates. The latter was supercooled and partially non-recrystallized, resulting in an increased crystal grain aspect ratio and excessive strength on the side wall of the can. Since G had a high temperature before the final pass of cold rolling, the precipitate distribution was excessive, and the strength anisotropy and can roundness deteriorated.

Claims (2)

Mg: 0.8-1.2% (mass%, the same shall apply hereinafter), Mn: 0.7-1.5%, Cu: 0.10-0.25%, Si: 0.1-0.3% , Fe: 0.1 to 0.3% contained, remaining Al and inevitable impurities, aspect ratio of crystal grains in a cross section parallel to the rolling direction (length in the rolling direction) / (length in the plate thickness direction) Is 10-30, and an intermetallic compound having a circle equivalent diameter of 0.1 μm or more and less than 0.3 μm is distributed in an area ratio of 0.3 to 0.8% in a cross section parallel to the rolling direction, and is equivalent to a circle. With respect to an aluminum alloy sheet in which an intermetallic compound having a diameter of 3 μm or more is distributed at an area ratio of 0.3 to 0.5% in a cross section parallel to the rolling direction, the drawing ratio is 1.5 to 2.0. Then, drawing is performed, and then redrawing with a drawing ratio of 1.1 to 1.3 and the thickness reduction rate of the side wall portion is 60 to 7 % Or three-stage ironing is continuously performed, baking is performed at a baking temperature of 200 ° C. for 15 minutes, and further, the drawing ratio is 12 to 15% near the opening of the can. An aluminum alloy plate for an aluminum bottle can body excellent in can roundness, characterized in that material strength anisotropy is 5% or less when a test piece is collected from a side wall portion of a necked molded body. Mg: 0.8-1.2%, Mn: 0.7-1.5%, Cu: 0.10-0.25%, Si: 0.1-0.3%, Fe: 0.1 An aluminum alloy ingot containing 0.3% of the balance Al and inevitable impurities is homogenized at 570 to 620 ° C. for 4 to 48 hours, cooled to 450 to 550 ° C., and then hot rough rolled. Start, to obtain a hot rough rolled plate having a rising temperature of 400 to 470 ° C.,
When rolling this hot rough rolled sheet with a tandem hot finishing mill,
The rolling oil sprayed onto the rolling rolls and / or the rolled sheet is set to 150 to 350 liters / minute per 1 m of the sheet width,
The total rolling reduction of hot finish rolling is 88 to 93%, the rolling speed is 270 m / min or more,
The coil side surface temperature immediately after winding in a coil shape is 310 to 340 ° C.,
Without intermediate heat treatment
By performing the cold rolling so that the coil rolling temperature is 80 to 150 ° C. immediately after winding after the cold rolling is finished and the coil rolling temperature is 75 to 87% in 2 to 4 passes.
The aspect ratio of the crystal grains in the cross section parallel to the rolling direction (length in the rolling direction) / (length in the plate thickness direction) is 10 to 30, and the circle equivalent diameter is 0.1 or more and less than 0.3 μm. An intermetallic compound is distributed in an area ratio of 0.3 to 0.8% in a cross section parallel to the rolling direction, and an intermetallic compound having a circle-equivalent diameter of 3 μm or more has an area ratio of 0.00 in a cross section parallel to the rolling direction. A method for producing an aluminum alloy plate for an aluminum bottle can body excellent in can roundness, characterized by being distributed at 3 to 0.5%.