JP6718701B2 - Method for producing aluminum alloy sheet for beverage can body excellent in anisotropy and neck formability, and for bottle can body excellent in anisotropy and bottle neck formability - Google Patents

Description

The present invention relates to a method for producing an aluminum alloy sheet for a beverage can body having excellent anisotropy and neck formability, and for a bottle can body having excellent anisotropy and bottle neck formability.

An aluminum-Mn-Mg-based alloy hard plate such as JIS3004 (AA3004) or JIS3104 alloy is used for a can body of an aluminum can for beverage. The alloy hard plate is required to have strength, corrosion resistance, a beautiful appearance, and excellent formability required for use as a container.
The alloy hard plate is manufactured through the steps of melting, casting, homogenizing, hot rolling, cold rolling, and the like, like a general aluminum alloy plate. And, generally, the strength and the moldability of each part of the can body are adjusted to 3/4 hard to extra hard with the optimum balance. That is, the aluminum alloy sheet is once recrystallized during rolling to be in a soft state, and then cold rolled at a rolling reduction of about 50 to 90% to obtain an appropriate strength mainly by work hardening.

When an aluminum alloy sheet is rolled using a recent industrial cold rolling mill, the material temperature rises due to the heat generated by rolling, and therefore sufficient ductility can be obtained even without rolling. Therefore, the aluminum alloy sheet is usually used in the as-rolled condition (H16 to H19). When sufficient ductility cannot be obtained, such as when the aluminum alloy sheet is rolled at a slow rolling speed, stabilizing annealing may be performed to use the H3X tempered aluminum alloy sheet.
However, if the mechanical properties of the rolled aluminum alloy plate are anisotropic, it may impair the formability of the can body, reduce the symmetry of the can body after forming, and increase the yield of materials used. There is a problem such as lowering. The anisotropy of the rolled plate depends on the orientation distribution (texture) of the crystal grains. Therefore, it is considered possible to reduce the anisotropy of the rolled aluminum alloy sheet by controlling the texture generated by recrystallization before cold rolling in consideration of the change in texture caused by cold rolling.

From the above viewpoint, it is important to control the recrystallization before cold rolling in order to control the anisotropy of the rolled aluminum alloy plate, and from this viewpoint, the method for manufacturing an aluminum can body material. Can be classified into the following three types.
(1) Hot rolling→recrystallization→final cold rolling The first method is to hot-roll a relatively thin-walled aluminum alloy sheet material having a thickness of, for example, 3 mm or less, and after hot rolling, wind it into a coil. This is a method in which the material is recrystallized as it is, or artificially annealed to recrystallize it, and then cold rolling is performed.
(2) Hot rolling→Cold rolling under low pressure→Recrystallization→Final cold rolling The second method is hot rolling to a relatively thin aluminum alloy sheet having a thickness of, for example, 3 mm or less, and then under relatively low pressure. For example, as described in Patent Document 1 below, a method of performing 6 to 15% cold rolling on an aluminum alloy sheet, annealing, and finally performing final cold rolling with a reduction rate of about 90% is used. is there.
(3) Hot rolling→Cold rolling→Recrystallization using a continuous annealing furnace→Final cold rolling under a relatively low pressure The third method is to perform the first cold rolling after the hot rolling of the aluminum alloy sheet material. Then, a continuous annealing furnace is used to perform rapid annealing at a relatively high temperature and then rapid cooling, and finally cold rolling at a relatively low pressure reduction rate of, for example, about 60%.

Japanese Patent No. 3644819

By the way, demands for lower prices of aluminum cans are strict, and therefore, attempts are being made to reduce the amount of materials used as much as possible. However, since it becomes difficult to balance the formability and anisotropy when the material plate thickness is thin, there is an increasing demand for a good balance between the formability and anisotropy.
For example, in order to control the anisotropy of an aluminum alloy sheet, it is effective to use a tandem hot finishing mill, and a single mill reverse hot finishing mill can obtain a sufficient cubic crystal orientation. However, there is a problem that the anisotropy is difficult to control.

Further, when the method (1) and the method (2) described above are compared, in the method described in (2), cold rolling under a relatively low pressure is performed as compared with the method described in (1). However, this cold rolling treatment has an advantage of promoting the development of cubic texture during annealing.
The present inventors have conducted various studies on conditions for producing aluminum cans for beverages using a single mill reverse type hot finish rolling machine, and as a result, can form a sufficient cubic orientation before cold rolling. The inventors have found a manufacturing method capable of controlling the anisotropy of an aluminum alloy plate for beverage cans, and arrived at the present invention.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a method for producing an aluminum alloy sheet for a beverage can body having excellent anisotropy and neck formability.

The manufacturing method of the aluminum alloy plate for a can body of the present invention is, in mass %, Si: 0.35% or less, Fe: 0.35 to 0.55%, Cu: 0.15 to 0.48%, Mn: An ingot obtained by smelting an aluminum alloy containing 0.8 to 1.15%, Mg: 0.60 to 1.60% and the balance being Al and inevitable impurities and semi-continuously casting After performing a hot rough rolling through a homogenization treatment and a soaking treatment to obtain a hot rough rolled plate of 25 to 16 mm, the temperature of the first pass leading side is 380° C. or less, and the temperature of the second pass leading side is 340° C. hereinafter, 3 pass Medellin side finishing temperature and 2 4 0-310 ° C., after hot finish rolling, performing a first cold rolling to a reduction ratio between 10% to 20%, then, a continuous annealing apparatus The first intermediate annealing is performed under the conditions of a holding temperature of 460 to 540° C. and a holding time of 5 to 60 seconds, followed by a second cold rolling at a reduction rate of 80 to 95%, and a sheet thickness of 0.210. It is characterized by obtaining an aluminum alloy plate having a 0.47 mm and a yield strength after baking of 230 to 320 N/mm 2.

In the method for producing an aluminum alloy sheet for a can body of the present invention, the homogenization treatment performed on the ingot is performed at 555 to 605°C for 4 to 10 hours, and the subsequent soaking treatment is 500 to 555°C. It is preferable that the heating is performed for 1 hour or more.
In the method for producing an aluminum alloy plate for a can body of the present invention, it is preferable that the final pass outlet side material temperature of the hot rough rolling is 400 to 460°C.

In the method for producing an aluminum alloy plate for a can body of the present invention, at least one of Cr: 0.05% or less, Zn: 0.25% or less, and Ti: 0.10% or less with respect to the above composition. Alternatively, an aluminum alloy containing two or more kinds can be used.
In the method for producing an aluminum alloy sheet for a can body of the present invention, it is preferable that after the second cold rolling, final stabilization annealing is performed under the conditions of a holding temperature of 120 to 140°C and a holding time of 2 to 4 hours.

The method for producing an aluminum alloy sheet for a can body of the present invention is to produce an aluminum alloy having a composition containing Si, Fe, Cu, Mn, and Mg in a specific range, and after hot rough rolling, define 1 to 3 passes. By performing hot finish rolling controlled to the outlet temperature, performing cold rolling with a reduction rate of 10 to 20%, performing continuous annealing under specific conditions, and performing final cold rolling with a reduction rate of 80 to 95%, It is possible to provide an aluminum alloy plate for a beverage can body and a bottle can body, which is excellent in both anisotropy and neck formability.
Further, by carrying out a stabilizing annealing in which the holding temperature and the holding time are controlled after the final cold rolling, it is possible to provide an aluminum alloy plate for a beverage can body and a bottle can body that are further excellent in anisotropy and neck formability. ..

Explanatory drawing which shows the apparatus and process used in a hot rolling process, when implementing the manufacturing method which concerns on this invention. The schematic block diagram which shows an example of the continuous annealing apparatus used for implementation of the manufacturing method which concerns on this invention. The process drawing which shows an example of the manufacturing method of a DI can. The partial cross section figure which shows an example of a DI can.

Hereinafter, each embodiment of the method for producing an aluminum alloy plate for a beverage can body having excellent anisotropy and neck formability according to the present invention will be described, but the present invention is not limited to the embodiments described below. Absent.
First, the composition of the aluminum alloy plate for a can body used in this embodiment will be described.
The aluminum alloy plate for a can body of this embodiment has a mass% of Si: 0.35% or less, Fe: 0.35 to 0.55%, Cu: 0.15 to 0.48%, Mn: 0. The aluminum alloy has a composition of 80 to 1.15%, Mg: 0.60 to 1.60% or less, and the balance of Al containing unavoidable impurities. Further, an aluminum alloy containing one or more of Cr: 0.05% or less, Zn: 0.25%, and Ti: 0.10% or less is used as the aluminum alloy having the above composition ratio. May be.
The reasons for limiting the composition of the aluminum alloy used in this embodiment will be described below.
The content of each element described in the present specification is% by mass unless otherwise specified, and includes the upper limit and the lower limit unless otherwise specified. For example, the notation of 0.35 to 0.55% means 0.35% or more and 0.55% or less.

"Si: 0.35% or less"
Si easily forms a compound with Mg contained at the same time and has a solid solution hardening action, a dispersion hardening action and a precipitation hardening action, and also forms a compound with Al, Mn, Fe, etc. to prevent seizure on the die at the time of forming. It has the effect of preventing. If the Si content exceeds 0.35 mass %, the workability deteriorates, which is inconvenient.
"Fe: 0.35-0.55%"
Fe has the effect of preventing crystal fineness and seizure on the die during molding. If the Fe content is less than 0.35 mass %, the desired effect cannot be obtained, and if it exceeds 0.55 mass %, the workability is deteriorated.

"Cu: 0.15-0.48%"
Cu easily forms a compound with Mg and contributes to solid solution hardening, dispersion hardening and precipitation hardening.
If the Cu content is less than 0.15 mass %, the desired effect cannot be obtained, and if it exceeds 0.48 mass %, the workability is deteriorated.
"Mn: 0.8-1.15%"
Mn easily forms a compound with Fe, Si, Al, etc., and acts as a crystallized phase and a dispersed phase to exhibit a dispersion hardening action and at the same time has the effect of preventing seizure on the die during molding. If the content of Mn is less than 0.8% by mass, desired curing characteristics cannot be obtained, and if it exceeds 1.15% by mass, workability deteriorates.
"Mg: 0.60 to 1.60%"
Mg has a solid solution strengthening action, enhances work hardenability by rolling, and exhibits dispersion hardening and precipitation hardening effects by coexisting with the Si and Cu. If the content of Mg is less than 0.60 mass %, the desired effect cannot be obtained, and if it exceeds 1.60 mass %, the workability is deteriorated.

The aluminum alloy used in this embodiment may contain one or more of the following Cr, Zn, and Ti in addition to the main components of Si, Fe, Cu, Mn, and Mg.
"Cr: 0.05% or less"
Cr exhibits the effect of preventing the seizure of the die during the miniaturization of the crystal and the molding process. If the content of Cr exceeds 0.05% by mass, it becomes brittle and the workability deteriorates.

"Zn: 0.25% or less"
Zn has a function of refining precipitates of Mg, Si, and Cu. If the Zn content exceeds 0.25% by mass, workability and corrosion resistance deteriorate.
"Ti: 0.10% or less"
Ti has an effect of refining crystal grains to improve workability. However, if the content of Ti exceeds 0.10 mass %, a coarse compound is formed and conversely the workability is deteriorated.

<Method for producing aluminum alloy sheet for beverage can body excellent in anisotropy and neck formability>
Next, an embodiment of a method for producing an aluminum alloy sheet for a beverage can body having excellent anisotropy and neck formability according to the present embodiment will be described.
In the method for producing an aluminum alloy plate for a beverage can body of the present embodiment, the aluminum alloy having the composition is melted, homogenized, and subjected to soaking to the ingot obtained by casting, and then hot working. Cans having a desired plate thickness are obtained by performing rough rolling and subsequent hot rolling by hot finish rolling, performing first cold rolling with a low reduction ratio, performing first intermediate annealing, and further performing final cold rolling. Obtain an aluminum alloy plate for a body.
Further, in addition to the above steps, the stabilization annealing can be performed under the conditions of a holding temperature of 120 to 140° C. and a holding time of 2 to 4 hours.
Hereinafter, the method for producing the aluminum alloy sheet for a beverage can body which is excellent in anisotropy and neck formability according to this embodiment will be described in the order of steps.

"casting"
After melting the aluminum alloy having the above composition, a cast ingot is cast from the molten aluminum alloy according to a conventional method, but prior to casting, when the aluminum alloy is melted, inclusions such as hydrogen gas and oxides are removed, An ingot is obtained by a continuous casting method.
The solidification rate at this time is usually 5 to 20° C./sec. The thickness of the cast ingot can be, for example, about 500 to 600 mm.
Next, chamfering is performed, and the surface of the ingot is cut by about 1 to 25 mm to produce a chamfered body. The chamfering may be performed after the homogenization treatment described later.

"Homogenization treatment"
Next, the produced chamfered body is subjected to homogenization treatment. The homogenization treatment is generally performed for homogenization of microsegregation generated by solidification of a molten metal, precipitation of a supersaturated solid solution element, transition of a metastable phase formed by solidification to an equilibrium phase, and the like.
In the homogenization treatment, it is important to set the homogenization temperature within the range of 555 to 605°C. If the homogenization temperature is less than 555° C., the effect of continuous annealing described below cannot be obtained, cracks are likely to occur in the hot rolling step and the first cold rolling step described below, and the ear rate of the final plate material increases. If the homogenizing temperature exceeds 605°C, the ingot may melt.

In the homogenization treatment, the chamfered body is preferably heated to a homogenization temperature at a heating rate of 100° C./hour or less. If the heating rate exceeds 100° C./hour, melting may occur partially.
Further, in the homogenization treatment, it is preferable that the time of maintaining at the homogenization temperature (homogenization time) is 4 hours or more and 10 hours or less. If the homogenization time is less than 4 hours, the homogenization may not proceed sufficiently. However, if the homogenization time is too long, there is no effect and the production efficiency decreases. From the above viewpoints, the preferable homogenization time is within the range of 4 to 10 hours. This homogenization treatment is usually performed by placing it in a batch-type furnace because the homogenization time is relatively long.
In the present embodiment, after the homogenization treatment, the chamfered body is further cooled to 500 to 555° C., soaking for holding for a predetermined time, and then hot rolling is started. The holding time (soaking time) in the temperature range of 500 to 555° C. can be 1 hour or more.

"Hot rolling"
The hot rolling is composed of hot rough rolling and subsequent hot finish rolling, and in the present embodiment, it is preferable to perform hot finish rolling using a single-mill reverse hot finishing mill.
In the hot rolling step, as shown in FIG. 1, after hot rough rolling to a plate thickness of about 20 mm using a hot rough rolling mill 20, to a plate thickness of 2 to 7 mm using a hot finish rolling mill 30. Hot rolling.

The hot rough rolling mill 20 shown in FIG. 1 is provided with, for example, upper and lower work rolls 21 and 22, backup rolls 23 and 24, and transport paths 4 and 6 in which a plurality of transport rollers are arranged, and has been transported from aluminum. This is an apparatus for passing the alloy plate material 5 between the work rolls 21 and 22 and rolling it to a target thickness.
In FIG. 1, the hot rough rolling mill 20 is provided with a sheet material 5 by repeatedly supplying a sheet material 5 of an aluminum alloy to the work rolls 21 and 22 from the conveying paths 4 and 6 on the left and right sides of the work rolls 21 and 22 and sequentially performing rough rolling. 5 can be rolled to a required thickness to form a plate material 7.

The hot finish rolling mill 30 shown in FIG. 1 is a single-mill reverse hot rolling mill, and is installed, for example, on the upper and lower work rolls 31, 32 and backup rolls 33, 34, and the entry side of these rolls. It comprises a reel-type delivery winding device 35 and a reel-type delivery winding device 36 installed on the delivery side. The hot finish rolling mill 30 has an operation of winding the sheet material sent out from the delivery winding device 35 and passed between the work rolls 31 and 32 to be hot-rolled by the delivery winding device 36, and from the delivery winding device 36. The operation of re-passing between the work rolls 31 and 32 and hot-rolling the plate material by the delivery winding device 35 is repeated a required number of times, and the interval between the work rolls 31 and 32 is gradually adjusted at each rolling operation. By doing so, it is an apparatus for hot finish rolling an aluminum alloy sheet material to a desired sheet thickness.

After the soaking treatment, the slab taken out of the soaking furnace usually starts hot rough rolling immediately, but the start of hot rough rolling may be delayed unless the slab temperature falls below 500°C. The number of passes of the hot rough rolling depends on the ingot (slab) thickness, the finished thickness, the slab width, the alloy composition, etc., but is generally in the range of 10 to 20 passes.
The hot rough rolling is performed by using a one-stand type rough rolling machine (a hot rough rolling machine 20 shown in FIG. 1) in which a transport table is usually installed before and after the rolling machine while the rolled material is thick. However, if the plate becomes thin, the required transport table length becomes long, the slack due to the weight of the plate becomes large, and the plate is easily cooled.

Therefore, in order to hold it on the transport table, the plate thickness needs to be ten and several millimeters or more. Therefore, the minimum plate thickness when the plate is sent from the rough rolling mill to the finishing rolling device depends on the coil weight and the plate width, but in the case of the weight and width industrially used, it is about 16 mm or more. preferable. Further, if the plate thickness when sending from the rough rolling mill to the finish rolling mill is too thick, the number of rolling passes in the finish rolling mill is increased and the productivity is reduced. Therefore, the upper limit of the plate thickness when sent to the finishing rolling mill is preferably 40 mm or less. When the aluminum alloy sheet material becomes thin from the upper limit to the lower limit of the above-mentioned thickness, hot finish rolling is performed by the single-mill reverse hot finishing mill having the configuration shown in FIG.

Hot finish rolling is performed using a single-mill reverse hot finishing mill.
By using a single-mill reverse-type hot finishing mill (hot finishing mill 30 shown in FIG. 1) having winding devices on both sides of the rolling mill, the hot finishing sheet thickness can be reduced.
Therefore, the reduction ratio of the subsequent cold rolling can be reduced, so that the number of passes of cold rolling can be reduced and the productivity can be improved. On the other hand, for example, when a hot finish rolling mill in which the winding device is installed on only one side is used, there is a minimum value for the plate thickness that can be held on the transport table, and therefore hot rolling can be performed. The minimum plate thickness will increase. Therefore, the cold reduction rate after hot rolling increases.

As described above, thinning the finished sheet thickness of hot rolling contributes to the improvement of productivity by reducing the number of cold rolling passes. Therefore, in the present embodiment, the finished plate thickness of the hot finish rolling is preferably within the range of 2 to 7 mm. If the finished plate thickness is less than 2 mm, the reduction ratio of the first cold rolling is insufficient, and a low ear ratio cannot be obtained. If the finished plate thickness exceeds 7 mm, the number of passes of the first cold rolling increases and the productivity decreases.
As conditions for hot finish rolling, the exit temperature of the first pass is set to 380°C or less, the exit temperature of the second pass is set to 340°C or less, and the exit temperature of the third pass (finishing temperature). that is preferably in the range of 2 4 0 to 310 ° C..
Further, the rolling reduction in the third pass is preferably 55% or more and 65% or less.

When the temperature on the exit side of the first pass is set to a temperature higher than 380°C, local strain during rolling acts as a driving force to partially recrystallize, mechanical properties are deteriorated, and random orientation There is a risk that the crystal grains will increase and the anisotropy will deteriorate.
When the temperature on the outlet side of the second pass is set to a temperature higher than 340° C., the same problem occurs due to the same phenomenon as the first pass.
Regarding the outlet temperature of the third pass, at a temperature of more than 310° C., the same phenomenon occurs as in the first pass, and the same problem occurs. 2 4 hardly occurs recrystallized grains nuclear cube orientation is 0 below ℃ temperature, not grow enough cubic orientation even if the first intermediate annealing following the first cold rolling to be described later, anisotropy Getting worse.
Regarding rolling reduction of the third pass, a similar problem in the same phenomenon as in the case of less than the above delivery temperature 2 4 0 ° C. occurs is less than 55%. If it exceeds 65%, the rolling load becomes too large, which causes a problem that it is difficult to perform stable rolling.

"First cold rolling"
In the first cold rolling step, the plate material that has been cooled after the hot rolling is cold rolled to a rolling reduction of 10 to 20%. The first cold rolling is a step necessary to give a driving force for preferentially growing the cubic-oriented nuclei formed by hot rolling in the subsequent first intermediate annealing. If the reduction ratio of the first cold rolling exceeds 20%, the strain becomes excessive, and the growth of the recrystallized grains of the cubic orientation formed by the hot rolling in the first intermediate annealing is hindered, and conversely the random orientation grows. Aggravates the anisotropy.
On the other hand, if the reduction ratio of the first cold rolling is less than 10%, it becomes difficult to control the rolling and the driving force for preferentially growing the cubic orientation in the first intermediate annealing is insufficient, which is also different. Directionality deteriorates.

"First intermediate annealing"
In the first intermediate annealing step, a holding temperature of 460 to 540° C. (range of 460° C. or more and 540° C. or less) is applied to the plate material after the first cold rolling by using a continuous annealing device having a basic configuration shown in FIG. ) Is held for 5 to 60 seconds and then cooled.
In the first intermediate annealing step, it is preferable to heat at a heating rate in the range of 10 to 200° C./sec (10° C./sec or more and 200° C./sec or less), and a cooling rate in the range of 10 to 200° C./sec ( It is preferable to perform cooling at a rate of 10° C./sec or more and 200° C./sec or less).
This annealing step brings the aluminum alloy sheet material into a semi-softened state, and it is preferable to set the yield strength after annealing; YS (Yield Strength) to a suitable range.
If the annealing temperature is lower than 460° C., the softening is insufficient and sufficient cubic oriented grains cannot be grown, resulting in deterioration of anisotropy. If the annealing temperature exceeds 540° C. or the holding time exceeds 60 seconds, the solid solubility of the solute element becomes excessive, the mechanical properties of the final product become high, and the neck formability of the can deteriorates.

FIG. 2 shows an example of the basic configuration of a continuous annealing device (Continuous Annealing Line: CAL). The continuous annealing device 40 of this example draws a long aluminum alloy plate 42 from a supply roll 41 and a shock absorber 43. Is supplied to a long furnace main body 44 of about several tens of meters to 100 m, is annealed under the above conditions while moving in the furnace main body 44, is drawn out from the furnace main body 44 after annealing, and is taken up by a winding device 47 via a shock absorber 46. It is a device that can be wound up. According to the continuous annealing device 40, the aluminum alloy sheet material 42 passing through the furnace body 44 can be continuously treated as a single body, and therefore, the annealing treatment can be performed under more accurate heating and cooling conditions than in the batch type annealing furnace. it can.

In the continuous annealing device 40, even if the width and diameter of the coil of the aluminum alloy plate 42 wound around the supply roll 41 are different, in other words, the width and thickness of the aluminum alloy plate 42 and the length to be processed. Even if they are different in size, they can be annealed in the order in which they are to be manufactured.Therefore, an increase in intermediate inventory is required compared to the case of a batch-type annealing furnace in which only coils of the same size were brought into the annealing furnace and annealed. Can be suppressed.

"Second cold rolling"
Next, the plate material after the first intermediate annealing is cold-rolled so that the rolling reduction is within the range of 80 to 95%. By setting the reduction ratio of the second cold rolling within the range of 80 to 95%, it is possible to achieve both the appropriate mechanical properties required for the plate material for a can body and the anisotropy/neck formability.
If the reduction ratio of the second cold rolling is less than 80%, the workability becomes insufficient, the required strength cannot be obtained, and work hardening easily occurs, which causes a problem of reducing the neck formability of the can.
If the reduction ratio of the second cold rolling exceeds 95%, the working ratio becomes excessive, the strength becomes excessive in some cases, and the anisotropy deteriorates.
By the second cold rolling, an aluminum alloy plate for beverage can bodies having a plate thickness of 0.210 to 0.47 mm can be obtained. The aluminum alloy plate preferably has a proof stress after coating and baking in the range of 230 to 320 N/mm ² .

"Stabilized annealing"
According to the above manufacturing method, an aluminum alloy plate for a can body having excellent anisotropy and neck formability can be obtained. However, in DI forming of the alloy plate, the bottom part may be formed depending on the shape and forming conditions of the bottom part of the can. There may be a problem of molding abnormality such as omission.
For this reason, it is possible to improve local formability such as can bottom forming by performing stabilizing annealing on the alloy sheet under the conditions of a holding temperature of 120 to 140° C. and a holding time of 2 hours to 6 hours. Can be effectively suppressed.

If the holding temperature is lower than 120° C., there is a problem in that the above effect is hardly observed, and if the holding temperature is higher than 140° C., there is a problem of strength reduction.
If the holding time is less than 2 hours, it becomes difficult to stably heat-treat the entire coil, and if the holding time exceeds 4 hours, the productivity is lowered.
By performing the stabilizing annealing treatment under the above-mentioned conditions, there is a feature that molding can be performed without causing abnormalities in can molding and problems of stable productivity.

The process of producing a DI can using the above-mentioned aluminum alloy plate and the outline of the DI can are described below.
FIG. 3 is a process diagram of a method for manufacturing a DI can, and FIG. 4 is a partial cross-sectional view showing the DI can. In these figures, reference numeral 10 indicates the DI can.
The DI can 10 is a bottomed cylindrical DI can made of an aluminum alloy, and is an aluminum alloy plate material having a plate thickness of 0.240 mm or more and 0.270 mm or less and an ironing rate of 54.2% or more 64. It is formed by drawing and ironing at 8% or less, and has, for example, a size in the axial direction of the can, that is, a height of about 122.5 mm and an outer diameter of 65 mm or more and 67 mm or less. The body portion has a wall thickness of 0.095 mm or more and 0.110 mm or less, a tensile strength of 340 MPa or more and 410 MPa or less, and a can body weight in this case of 11.6 g or less.

Further, as shown in FIG. 4, the bottom portion 12 is provided with a dome portion 12a that is recessed inward in the can axis direction of the body portion 11, and the outer peripheral edge portion of this dome portion 12a is in the can axis direction of the body portion 11. It is an annular convex portion 12c protruding outward. The top of the annular convex portion 12c in the can axis direction is a grounding portion 12b that contacts the grounding surface L when the DI can 10 is placed on the grounding surface L so that the DI can 10 is in an upright posture. ..
Further, the DI can 10 is printed and painted on the outer surface of the body portion 11 including a printed portion of character information and the like by using a polyester-based paint, and the outer surface printed and outer surface-painted DI can 10 is subjected to 180° C. After forming a coating film of 50 mg/dm ² by heating for 30 seconds, the inner surface of the DI can 10 is coated with an epoxy-based coating, and heated at 200° C. for 60 seconds to 40 mg/dm ^2. The outer surface printing, the outer surface coating, and the inner surface coating with the coating film of are formed.

This DI can is manufactured, for example, by the following steps.
The aluminum alloy plate obtained in the above process is punched out to form a disc-shaped plate material (blank) W having a diameter of about 150 mm.
Next, the plate material W is drawn by a cupping press to form a cup-shaped body W1.
Next, the cup-shaped body W1 is re-drawn and ironed by a DI processing device to form a bottomed cylindrical body W2. At this time, the ironing rate is, for example, 60.4%, and the drawing and ironing process is performed until the thinnest portion of the body portion 11 has a thickness of 0.100 mm.

A DI processing apparatus used for redrawing and ironing includes a single redrawing die having a circular through hole for redrawing and a plurality of circular throughholes arranged coaxially with the redrawing die ( For example, three ironing dies (ironing dies) are coaxial with the ironing dies, which can be fitted in the through holes of the respective ironing dies and can be moved in the axial direction. It is provided with a cylindrical punch sleeve and a cylindrical cup holder sleeve fitted on the outside of the punch sleeve.

In the redrawing processing by the DI processing device, the cup- shaped body W1 is arranged between the punch sleeve and the redrawing die, the cup holder sleeve and the punch sleeve are advanced, and the cup holder sleeve is placed on the end surface of the redrawing die. The punch sleeve pushes the cup- shaped body W1 into the through hole of the redrawing die while pressing the bottom surface of the body W1 to perform the cup pressing operation. As a result, a redrawn cup having a predetermined inner diameter is formed. Successively, the re-drawn cup is passed through a plurality of ironing dies sequentially to gradually iron and squeeze the side wall of the cup-shaped body to extend the side wall to increase the side wall height and the wall thickness. Is thinned to form a bottomed tubular body W2.

The bottomed cylindrical body W2 that has undergone the ironing process is formed in a dome shape, for example, by the punch sleeve pushing further forward and pressing the bottom portion against the bottom molding die.
The bottomed cylindrical body W2 is cold work-hardened due to the side wall being squeezed, so that the strength is increased.

Next, the open end W2a of the bottomed tubular body W2 is trimmed.
Since the open end W2a of the bottomed tubular body W2 formed by the DI processing device is uneven and has a wavy shape in the can axis direction, the open end W2a of the bottomed tubular body W2 is By cutting and trimming, the height of the side wall in the axial direction of the can is made uniform over the entire circumference.
In this way, a DI can 10 having a body 11 and a bottom 12 and having a circular cross section can be formed.

If the aluminum alloy plate obtained by the above-described manufacturing method is used, it is possible to improve the neck moldability even when it is subjected to the ironing process in the above-described DI can manufacturing method, and it is possible to prevent scratches and molding defects. It is possible to obtain an aluminum can that does not cause problems.

Hereinafter, the method for producing an aluminum alloy plate for a can body according to the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples.
The aluminum alloys having the compositions shown in Tables 1 and 2 were melted, degassed, and the melt was filtered, and then cast into a slab having a thickness of 600 mm, a width of 1100 mm, and a length of 4.5 m by semi-continuous casting. Note that the contents of Cr, Zn, and Ti in each slab of this example are almost the same, and Cr = 0.02 to 0.03%, Zn = 0.15 to 0.17%, and Ti = 0.02 to 0, respectively. It was 0.03%.

Next, after the slab was faced, a homogenizing/soaking furnace was used to perform homogenizing treatment at a holding temperature of 565° C. and a holding time of 8 hours, and then cooled in the furnace to a holding temperature of 545° C. Soaking was performed at the holding temperature for a holding time of 1 hour or more.
Subsequently, after hot rough rolling to a plate thickness of 20 mm using the hot rough rolling mill 20 having the configuration shown in FIG. 1, using the single-mill reverse hot finishing mill 30 shown in FIG. Sheet materials with various finished thicknesses were obtained by hot finish rolling.
The outlet temperature of the hot rough rolling was 430° C. as shown in Tables 1 and 2.
The exit temperature of the first pass of hot finish rolling is adjusted to 375 to 385° C. as shown in Table 1 and Table 2, the exit temperature of the second pass is adjusted to 330 to 345° C., and three passes are applied. The outlet temperature of the eye was adjusted to 225 to 315°C.

Next, after subjecting the sheet material after the hot rolling to the first cold rolling at the reduction rate (first cold rolling rate) shown in Tables 3 and 4, the continuous annealing device was used to set forth in Tables 3 and 4 At the holding temperature, the average heating rate from room temperature to the holding temperature is 25° C./sec, the holding time is 5 to 60 seconds, and the average cooling rate from the highest temperature to 70° C. is 50° C./sec. ) Went.
Next, the plate material after the first intermediate annealing was subjected to the second cold rolling at the rolling reductions (second cold rolling reductions) shown in Tables 3 and 4, and the can bodies having the plate thicknesses (mm) shown in Tables 3 and 4 were obtained. An aluminum alloy plate for use was obtained.
Further, a part of the obtained aluminum alloy sheet for a can body was further subjected to stabilization annealing under the conditions of holding time at the holding temperature shown in Tables 3 and 4 for 3 hours using a batch type annealing furnace. It was

The material strength (ASTS) of the obtained aluminum alloy sheet for a can body was obtained by a tensile test according to JIS Z2241, and further heat treatment equivalent to coating baking was performed under the condition of 210° C.×10 minutes to obtain a yield strength (ABYS, 0 after baking). .2% proof stress) was measured.
The physical property values (ASTS) were measured for samples taken from three or more positions in the width direction and the longitudinal direction of the coil, and the allowable range for the ASTS variation (maximum value-minimum value) was less than 8 MPa. ..
The blank material of the obtained aluminum alloy plate for a can body was processed into a beverage can having a capacity of 350 cc.

"Ear rating"
As anisotropy evaluation of the obtained aluminum alloy plate for a can body, the ear rate in cup molding was measured.
The ear ratio was calculated from the height of the side wall of the cup obtained by deep drawing the material with an Erichsen tester. The processing conditions were: punch diameter: 33 mm (flat head punch), drawing ratio: 1.75, wrinkle holding force: 3 kN. The side wall height of this cup was measured with a digital micrometer, and the ear rate was calculated by the following formula.
(Mountain average height-valley average height)/valley average height x 100 = ear ratio (%)
The average heights of the ridges of 0° and 180° and the average heights of the ridges of 45°, 135°, 225°, and 315° were obtained, and the higher one was defined as the average height of the ridges in the above formula. Further, the valley average heights of 90° and 270° were obtained and set as the valley average height in the above formula.
For the evaluation of anisotropy by ear rate, the average value of n=3 is “⊚” when less than 1.5%, “◯” when 1.5% or more and less than 2.5%, and 2.5% or more 3. Less than 5% was designated as "△" and 3.5% or more was designated as "x". “⊚” and “∘” were judged as passing levels.

The neck moldability was evaluated by molding all samples into 350 cc beverage cans. After the DI molding, the mouth end of the can was removed by trimming, and after washing and drying, the inner and outer surfaces of the can were painted and printed, die neck molding and spin flow molding were performed, and the neck shape of a 350 cc beverage can having an inner diameter of approximately 55 mm was obtained. Note that when the DI forming, by reducing the thickness of the portion receiving the neck molding promoted evaluated cracks occurring in portions to form a curled portion and a threaded portion have your neck molding. Twenty-four cans of each sample were manufactured, and the number of cans having cracks in the curl portion and the portion corresponding to the formation of the screw portion was visually counted to determine the neck molding defect rate. The case where no neck molding defect was observed was marked with ⊚, the neck molding defect rate of 5% or less was marked with ◯, and the neck molding defect rate of 5% to 10% was marked with Δ, and X exceeding 10%. The case of ⊚ or ○ was judged to be acceptable, and Δ or × was judged to be unacceptable.
The above results are shown in Tables 1 to 4 below.

As shown in Table 1 and Table 3, the sample samples of Nos. 1 to 16 are desirable alloy components, the exit temperature of the first pass to the third pass, the first cold rolling reduction, and the first intermediate annealing conditions. Since it satisfied the second cold rolling reduction, it was an aluminum alloy plate having excellent AB yield strength, no anisotropy, and excellent neck formability.
In contrast to these example samples, the comparative example sample of No. 17 is a sample in which the exit temperature of the first pass of hot finish rolling is set to 385° C., which is higher than the desired range of 380° C. or less, It deteriorated and caused a problem in neck moldability.
The comparative sample of No. 18 was a sample in which the exit temperature of the second pass of hot finish rolling was set to 345° C., which is higher than the desirable range of 340° C. or lower, but the anisotropy deteriorated and the neck formability was also deteriorated. Caused a problem.
The comparative example sample of No. 19 was a sample in which the exit temperature of the third pass of hot finish rolling was set to 315° C., which was higher than the desired range of 310° C. or less, but both the anisotropy and the neck formability deteriorated.

The comparative sample of No. 20 is a sample in which the outlet temperature of the third pass of hot finish rolling is set to 225° C., which is lower than the desirable range of 240 ° C. or higher, but the anisotropy deteriorates and the neck formability is also deteriorated. Caused a problem.
The sample of Comparative Example No. 21 is a sample in which the rolling reduction of the first cold rolling is set to 8%, which is lower than the desirable range of 10% or more, but the anisotropy deteriorates and a problem occurs in neck formability. It was
The comparative sample of No. 22 was a sample in which the rolling reduction of the first cold rolling was set to 22%, which was higher than the desirable range of 20% or less, but both the anisotropy and the neck formability deteriorated.
The comparative sample of No. 23 was a sample not subjected to the first intermediate annealing treatment, but both the anisotropy and the neck formability deteriorated.
The sample of Comparative Example No. 24 was a sample in which the temperature of the first intermediate annealing treatment was too low, but both the anisotropy and the neck formability deteriorated.
The comparative sample of No. 25 was a sample in which the temperature of the first intermediate annealing treatment was too high, but the anisotropy was good, but the neck formability deteriorated.

The sample of Comparative Example No. 26 was a sample in which the Si content in the aluminum alloy component was excessively large, but the anisotropy was good, but the neck formability was deteriorated.
The comparative example sample of No. 27 is a sample in which the Fe content is too low in the components of the aluminum alloy, and the comparative example sample of No. 28 is a sample in which the Fe content is too high, but the anisotropy is good. However, the neck moldability deteriorated, and when the amount of Fe was small, seizure occurred in the die.
Sample Comparative Sample of No.29 is that too small a Cu content in the components of the aluminum alloy, although Comparative Sample of No.30 is a sample too much Cu content, AB in the case of Cu under- The yield strength decreased, the anisotropy deteriorated, and the neck formability deteriorated when Cu was excessive.
The comparative example sample of No. 31 is a sample in which the Mn content is too low in the aluminum alloy component, and the comparative example sample of No. 32 is a sample in which the Mn content is too high. Both the directionality and the neck formability deteriorated, and seizure occurred, and when Mn was excessive, the anisotropy deteriorated and the neck formability deteriorated.
The comparative example sample of No. 33 is a sample in which the Mg content in the aluminum alloy component is too low, and the comparative example sample of No. 34 is a sample in which the Mg content is too high. Both the directionality and the neck formability deteriorated, and when Mg was excessive, the anisotropy deteriorated, and the neck formability also deteriorated.
The sample of the comparative example of No. 35 was a sample in which the temperature of the stabilizing annealing was made too high, but the anisotropy and the neck formability were good, but the AB proof stress decreased.

4, 6... Conveyance path, 5, 7... Plate material, 10... DI can, 11... Body part, 12... Bottom part , 12a... Dome part, 12b... Grounding part, 12c... Annular convex part, 13... Neck part, 14... Flange portion (curl portion and screw portion forming equivalent portion) 20 ... Hot rough rolling mill, 21, 22... Work roll, 23, 24... Backup roll, 30... Hot finish rolling mill, 31, 32... Work roll , 33, 34... Backup rolls, 35, 36... Delivery winding device, 40... Continuous annealing device, 41... Supply roll, 42... Aluminum alloy plate material, 43, 46... Buffer device, 44... Furnace body, 47... Winding device Roll , W... Plate material, W1... Cup-shaped body, W2... Bottomed cylindrical body, W2a... Open end .

Claims (5)

In mass %, Si: 0.35% or less, Fe: 0.35 to 0.55%, Cu: 0.15 to 0.48%, Mn: 0.8 to 1.15%, Mg: 0.60. ˜1.60%, the balance being Al and an unavoidable impurity, an aluminum alloy having a composition is melted, and the ingot obtained by semi-continuous casting is subjected to homogenization treatment and soaking treatment, and hot rough rolling is performed. 25 to 16 mm of a hot rough rolled plate, and then the first pass temperature on the first pass side is 380° C. or less, the second pass temperature on the second pass side is 340° C. or less, and the third pass temperature on the second finish side is 2 40 to 0. After the hot finish rolling at 310° C., the first cold rolling at a reduction rate of 10 to 20% is performed, and then the continuous annealing device is used to maintain a holding temperature of 460 to 540° C. and a holding time of 5 to 5. The first intermediate annealing is performed under the condition of 60 seconds, and then the second cold rolling is performed at a reduction rate of 80 to 95% to obtain a sheet thickness of 0.210 to 0.47 mm and a yield strength of 230 to 320 N/mm2 after baking. Aluminum alloy plate for beverage can body excellent in anisotropy and neck formability, characterized by obtaining aluminum alloy plate, and method for producing aluminum alloy plate for bottle can body excellent in anisotropy and bottle neck formability .. The homogenization treatment performed on the ingot is performed at 555 to 605° C. for 4 to 10 hours, and the subsequent soaking treatment is performed at 500 to 555° C. for 1 hour or more. An aluminum alloy plate for a beverage can body excellent in anisotropy and neck formability according to claim 1, and a method for producing an aluminum alloy plate for a bottle can body excellent in anisotropy and bottle neck formability. The final pass outlet material temperature of the hot rough rolling is 400 to 460° C. The aluminum alloy for a beverage can body excellent in anisotropy and neck formability according to claim 1 or 2, Plate and a method for producing an aluminum alloy plate for a bottle can body having excellent anisotropy and bottleneck formability. Use of an aluminum alloy further containing at least one or more of Cr: 0.05% or less, Zn: 0.25% or less, and Ti: 0.10% or less with respect to the above composition. An aluminum alloy plate for a beverage can body excellent in anisotropy and neck moldability according to any one of claims 1 to 3, and a bottle excellent in anisotropy and bottle neck moldability. Manufacturing method of aluminum alloy sheet for can body. After the second cold rolling, final stabilization annealing is performed under the conditions of a holding temperature of 120 to 140° C. and a holding time of 2 to 4 hours, and the difference according to any one of claims 1 to 4. A method for producing an aluminum alloy plate for a beverage can body having excellent toughness and neck formability, and an aluminum alloy plate for a bottle can body having excellent anisotropy and bottle neck formability.

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