JP2010053367A - Aluminum alloy sheet for can end, and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aluminum alloy sheet for a can end, which is particularly superior in a bulge pressure even though having been thinned, keeps pressure resistance, and is also superior in formability and opening easiness that tend to become problems when the aluminum alloy sheet is thinned, and to provide a method for manufacturing the same. <P>SOLUTION: The aluminum alloy sheet has a composition comprising 4.3 to 5.5% Mg, 0.35 to 0.55% Mn, 0.04 to 0.30% Si, 0.12 to 0.40% Fe, and the balance Al with unavoidable impurities; has a sheet thickness of 0.20 to 0.25 mm; has an organic resin film formed on one side or both sides thereof; and shows such mechanical properties that when tensile tests in directions of 0&deg;, 45&deg;and 90&deg;with respect to a rolling direction of the aluminum alloy sheet have been conducted, a difference between the minimum value of yield stress and the minimum value of tensile strength is 30 to 65 MPa. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an aluminum alloy plate for can ends, and more specifically, can end materials for beverage cans and food cans that do not decrease in bulge pressure even if they are thinned. Especially, positive pressure cans (beer, carbonated, or filled with nitrogen gas). The present invention relates to an aluminum alloy plate for can ends used for an end for cans to which internal pressure is applied and a method for producing the same.

  Among beverage cans, beer cans, and canned aluminum alloy plates used for positive pressure cans with high can internal pressure, such as soft drink cans containing carbonic acid, need strength that can withstand can internal pressure, In recent years, thinning of can end materials has been required from the viewpoint of cost reduction and environmental load reduction. If thinning is done with a normal manufacturing method, it cannot withstand the internal pressure of the can even with the same material strength. Is required.

  The ability to withstand the can internal pressure required for the positive pressure can end is pressure resistance and bulge pressure. When positive pressure cans such as beer and carbonated drinks are left in places where the temperature is high, such as in a car in the summer, the internal pressure of the can rises and the end of the can swells. However, the pressure inside the can at this time is called pressure resistance, and if the pressure resistance is low, buckling occurs easily and the mouth end of the can end opens, Some cracks occur, causing problems such as the contents blowing out.

  Moreover, when packing and transporting a positive pressure can filled with beer or carbonated beverage, the can internal pressure rises due to a rise in temperature or vibration, and the can end swells. Normally, at normal temperature, the tab position is lower than the tightening position with respect to the height direction of the can, but when the can end swells in this way, the tab position rises and comes into contact with the packaging material. The internal pressure at this time is called the bulge pressure. If the bulge pressure is low, the tab and the packing material easily come into contact with each other due to the expansion of the can end, and as a result, vibration is transmitted to the tab during transportation, and the drinking mouth is damaged due to fatigue. The problem of opening will occur.

  As is clear from the above definition, the bulge pressure is lower than the pressure resistance, but when the can internal pressure reaches the bulge pressure and pressure resistance, the material forming the can end is plastically deformed. However, since the amount of plastic deformation at the time of reaching the bulge pressure and the pressure resistance is different, the can end having a high pressure resistance does not necessarily have a high bulge pressure.

  Since the amount of plastic deformation of the material when the bulge pressure is reached is relatively small, in order to obtain a high bulge pressure, it is desirable that the material begins to plastically deform, that is, a material having a high yield strength in terms of the tensile properties of the material. On the other hand, since the plastic material has already undergone plastic deformation when the pressure resistance is reached, in order to obtain a high pressure resistance, it can be said by the stress corresponding to the deformation stress after work hardening due to plastic deformation, that is, the tensile properties of the material. If the tensile strength is high, it is desirable.

  Furthermore, since the material has strength anisotropy, naturally, deformation starts from a position where strength is weak and buckling occurs. Therefore, in order to predict the performance based on the tensile properties of the material, it must be evaluated in the direction of the weakest strength. In this case, the difference in strength between the direction of high strength and the direction of low strength is not important, and it is obvious that the evaluation may be made in the direction of the lowest strength.

  On the other hand, there are moldability and openability as characteristics that are problematic due to thinning. In the can end molding, rivet molding is particularly severe, but the rivet diameter required to fix the tab does not change even if the thickness is reduced, so the distortion due to processing increases by the reduced thickness, which is higher. Formability is required.

  Further, a groove called a score is formed at a position where the end drinking mouth opens. After the contents are filled and tightened, the remaining thickness of the score (difference between the original plate thickness and the groove depth of the score) is managed to prevent unexpected opening due to internal pressure. Even so, the thinner the original plate thickness, the smaller the score processing amount, and the more difficult the score opens. In addition, when opening the score, the stress is concentrated in the groove by pressing the inside of the score with the tab. At this time, if the plate thickness is thin, the score itself is pushed by the tab and bends, causing the groove to enter the groove. The stress that concentrates is reduced, and the crack may break along the score in the middle of opening. As described above, when the thickness is reduced, a problem arises that the amount of molding increases geometrically and the rigidity decreases.

  As described above, when the can end material is simply thinned, both the pressure resistance and the bulge pressure are lowered, and the pressure resistance and the bulge pressure required for the positive pressure can end cannot be secured with the same tensile characteristics as in the past. In addition, as the material becomes thinner, the new issues of securing the moldability of the can end material and securing the opening of the can end must be overcome. There is a strong demand for aluminum alloy plates for can ends that can be made to be able to be made.

Up to now, as an example of paying attention to tensile properties in three directions in an aluminum alloy plate for high pressure can end, after hot rolling under specific conditions for an aluminum alloy containing Mg and Mn as essential components A method for producing an aluminum alloy sheet that is subjected to cold rolling has been proposed (see Patent Document 1), but the required pressure and bulge pressure required as a positive pressure can end can be secured even if the wall thickness is reduced, and formability and opening are further improved. It is difficult to ensure sex. While attempts have been made to specify hot rolling conditions and cold rolling rates and to specify components such as Mg and Mn (see Patent Documents 2 and 3), this combination does not necessarily ensure pressure resistance and bulge pressure. It is not possible to obtain tensile properties.
Japanese Patent Laid-Open No. 3-28749 Japanese Patent Laid-Open No. 4-176848 JP 2001-164347 A

  In order to obtain an aluminum alloy sheet for can end that can satisfy the above characteristics at the same time even if the thickness is reduced, the inventor conducted multifaceted tests and studies on alloy components, manufacturing processes, and combinations thereof. In the process, it is possible to obtain excellent pressure resistance and bulge pressure by controlling the content of Mg and Mn among the alloy components, especially the cold rolling rate and the heating rate during paint baking among the production methods. I found it.

  The present invention has been made on the basis of the above examination results, and the purpose thereof is excellent in bulge pressure even when the thickness is reduced, and at the same time, the pressure resistance is maintained, and the moldability that becomes a problem with the thickness reduction and An object of the present invention is to provide an aluminum alloy plate for can ends that is excellent in openability and a method for producing the same.

  In order to achieve the above object, the aluminum alloy plate for can end according to claim 1 is Mg: 4.3-5.5%, Mn: 0.35-0.55%, Si: 0.04-0. 30%, Fe: 0.12 to 0.40%, further containing 0.10% or less of Cu, Cr, Zn, and Ti, respectively, and having a composition comprising the balance Al and inevitable impurities. A 20 to 0.25 mm aluminum alloy plate, one or both surfaces of which are coated with an organic resin film, and subjected to a tensile test in directions of 0 °, 45 °, and 90 ° with respect to the rolling direction of the aluminum alloy plate. The difference between the minimum value of the proof stress and the minimum value of the tensile strength is 30 to 65 MPa.

  The aluminum alloy plate for can ends according to claim 2 is characterized in that, in claim 1, the thickness per one side of the organic resin film is 1 to 20 μm.

  According to a third aspect of the present invention, there is provided a method for producing an aluminum alloy plate for a can end, the homogenizing heat treatment step of holding the aluminum alloy ingot having the composition according to claim 1 at a temperature of 460 to 540 ° C. for 2 to 24 hours; When hot ingot and hot finish rolling are performed on the ingot subjected to hydrothermal treatment, the hot rough rolling is finished in the temperature range of 460 to 540 ° C and the hot finish rolling is finished in the temperature range of 300 to 370 ° C. Hot rolling step to obtain a recrystallized structure, and cold rolling in a temperature range of room temperature to 180 ° C. and a reduction rate of 70 to 93%, and a cold rolled plate having a thickness of 0.20 to 0.25 mm When the organic resin film is coated and baked on one side or both sides of the cold-rolled plate, the temperature reached by the plate is 230 to 270 ° C. at a heating rate of 10 ° C./s or more after coating. The painting baking process to bake under the conditions And wherein the Mukoto.

  The method for producing an aluminum alloy sheet for can ends according to claim 4 is the method according to claim 3, wherein after the hot rolling step or during the cold rolling step, intermediate annealing is performed, and the intermediate annealing is performed, A cold rolling step in which a cold rolled sheet having a thickness of 0.20 to 0.25 mm is obtained by cold rolling in a temperature range of ˜180 ° C. and a reduction rate of 70% to 93%, and after the cold rolling step In addition, when an organic resin film is coated and baked on one or both surfaces, it includes a coating baking process in which baking is performed at a temperature rising rate of 10 ° C./s or more after coating and at a plate temperature of 230 to 270 ° C. And

  According to the present invention, even if the thickness is reduced, the bulge pressure is excellent, the pressure resistance is maintained at the same time, the strength reduction after the coating baking process is suppressed, and the moldability and openability that become a problem with the thickness reduction are also achieved. An excellent aluminum alloy plate for a bulge pressure improving can end and a method for producing the same are provided.

The significance of the alloy components of the aluminum alloy plate for can ends according to the present invention and the reason for limitation thereof will be described.
Mg is an important additive element that functions to provide the necessary proof stress and tensile strength to ensure the desired bulge pressure and pressure resistance, and the preferred content is in the range of 4.3 to 5.5%. is there. If it is less than 4.3%, the proof stress and tensile strength required to secure the bulge pressure and pressure resistance cannot be obtained, and if it exceeds 5.5%, hot workability is inferior and cracking occurs during hot rolling. It becomes easy and decreases productivity.

  Mn, together with Mg, is not only an important additive element that functions to provide the necessary proof stress and tensile strength in order to ensure the desired bulge pressure and pressure resistance, but also greatly increases the openability, rivet formability, etc. It is an influential element and must be strictly controlled. If it is less than 0.35%, the proof stress and tensile strength necessary to ensure the bulge pressure and the pressure resistance cannot be obtained, and when opening the mouth end of the can end, Al- Mn, Al-Mn-Fe, Al-Mn-Si, Al-Mn-Fe-Si intermetallic compound is insufficient, the opening force of the can end becomes too high, and the groove of the opening is derailed. There is also. When the amount of Mn exceeds 0.55%, the above-described intermetallic compound increases too much, and cracks easily propagate, so that the formability of the product plate, particularly the rivet formability, is significantly lowered.

Si and Fe are unavoidable elements from the viewpoint of using recycled materials. The preferable content of Si is in the range of 0.04 to 0.3%. If it is less than 0.04%, the purity of the raw metal that is the melting raw material has to be increased, which not only increases the cost but also recycles. The material cannot be used. When Si exceeds 0.3%, coarse Mg ₂ Si generated as a crystallized product increases, and the amount of Mg solid solution that contributes to strength decreases, resulting in the same problem as when the amount of Mg is too small. In addition, Mg ₂ Si, Al—Mn—Si, Al—Mn—Fe—Si, and Al—Fe—Si intermetallic compounds become too much, and problems similar to the case where the amount of Mn is too much arise.

  The preferable content of Fe is in the range of 0.12 to 0.4%, and if it is less than 0.12%, the purity of the bare metal as the melting raw material has to be increased, and the same as when the amount of Si is too small. Problems arise. When the amount of Fe exceeds 0.4%, there are too many Al-Fe, Al-Mn-Fe, Al-Mn-Fe-Si, Al-Fe-Si intermetallic compounds, and too much Mn amount. Similar problems arise.

  In the present invention, Cu, Cr, Zn, and Ti as impurities must be limited to 0.10% or less, respectively. If each of these elements exceeds 0.10%, the recyclability of the can end is hindered, which is not desirable. Moreover, since these transition metal elements form an intermetallic compound similarly to Mn and Fe, the same problems as when the amount of Mn is too large are likely to occur.

  The thickness of the aluminum alloy plate for can ends according to the present invention is preferably 0.20 to 0.25 mm. When the plate thickness is less than 0.20 mm, it is difficult to ensure the pressure resistance and bulge pressure required for the positive pressure can end. When it exceeds 0.25 mm, it is not different from a conventionally used can end material, and does not contribute to the cost reduction effect and the environmental load reduction. In order to make the cost reduction effect and environmental load reduction effective, a plate thickness of 0.24 mm or less is more preferable.

  The difference between the minimum value of the proof stress and the minimum value of the tensile strength when performing a tensile test in the direction of 0 °, 45 °, and 90 ° with respect to the rolling direction of the aluminum alloy sheet is preferably 30 to 65 MPa, If the difference between the minimum value of the proof stress in three directions and the minimum value of tensile strength is less than 30 MPa, the amount of plastic deformation from when the material starts plastic deformation until it breaks is small, and the formability is poor. On the other hand, if the difference exceeds 65 MPa, the material is easily plastically deformed with a low strain amount, so that the bulge pressure required for the positive pressure can end cannot be obtained. In order to stably obtain the bulge pressure regardless of the lid shape, it is desirable that the minimum value of the proof stress is 315 MPa or more.

  The thickness per one side of the organic resin film provided on one or both sides of the aluminum alloy plate for can ends of the present invention is desirably 1 to 20 μm, and if it is less than 1 μm, the barrier property required for the can end material is ensured. The metal material may corrode with components of the content that has passed through the film after the content has been filled. On the other hand, if the thickness exceeds 20 μm, the coating and baking process must be performed at a continuous coating baking line, the aluminum alloy sheet coated with the paint must be held at a high temperature, and the baking process must be maintained at a high temperature for a long time. In addition to the fact that the recovery of the material progresses and the proof stress is excessively lowered and the bulge pressure required for the positive pressure can end cannot be obtained, the line speed must be lowered and the productivity is inferior.

Hereinafter, the manufacturing method of the aluminum alloy plate for can ends which concerns on this invention is demonstrated.
The aluminum alloy having the above composition is melted and cast according to a conventional method, and the resulting ingot is subjected to homogenization heat treatment. The homogenization heat treatment is preferably performed at 460 to 540 ° C. for 2 to 24 hours. If the homogenization heat treatment temperature is less than 460 ° C., it takes a long time to homogenize and the productivity is poor. When it exceeds 540 degreeC, there exists a possibility that the eutectic compound formed at the casting process may melt | dissolve. If the homogenization heat treatment time is less than 2 hours, it is difficult to obtain the effect of homogenization. If the homogenization heat treatment time exceeds 24 hours, not only is the productivity inferior, but the ingot surface is oxidized and streak defects on the rolled surface of the product plate. May occur and the surface quality may be deteriorated.

  After the homogenization heat treatment, hot rough rolling is performed. The end temperature of the hot rough rolling temperature is preferably 460 to 540 ° C., and if it is less than 460 ° C., the load required for rolling increases, and the reduction amount per pass must be reduced, thereby impairing productivity. When it exceeds 540 degreeC, there exists a possibility that the crack resulting from melting of a eutectic compound may arise.

  Hot finish rolling is performed following hot rough rolling. The end temperature of hot finish rolling is preferably 300 to 370 ° C. If it is less than 300 ° C, a recrystallized structure cannot be obtained at the end of hot rolling, which causes variations in strength and in-plane anisotropy. In particular, when manufacturing in the process of cold rolling to the product sheet thickness without intermediate annealing, the variation in in-plane anisotropy for each production lot becomes significant, and the variation in lip height distribution after lid making becomes large. However, the substantial cold work degree becomes too high, and there is a possibility that an ear crack occurs during the cold rolling to inhibit the productivity and the formability of the product plate is lowered. If the temperature exceeds 370 ° C., the oxide film aggregates on the roll due to the friction between the rolling surface and the rolling roll, which may cause streak defects on the rolling surface.

  Thereafter, cold rolling is performed to obtain a predetermined plate thickness (0.20 to 0.25 mm). The rolling reduction of cold rolling is preferably 70 to 93%. If it is less than 70%, the yield strength becomes too low for the tensile strength, and the bulge pressure required as a positive pressure can end material is secured. Difficult to do. If it exceeds 93%, work hardening proceeds too much, the difference between the proof stress and the tensile strength becomes small, and the moldability of the product plate may be lowered.

  Cold rolling is preferably performed in a temperature range of room temperature (20 to 25 ° C.) to 180 ° C. If the cold rolling temperature exceeds 180 ° C., the material recovers during or immediately after the cold rolling, and the product It becomes difficult to form a dense dislocation cell structure on the plate, and as a result, the yield strength becomes too low, and it becomes difficult to secure a bulge pressure. In addition, you may perform intermediate annealing as needed before cold rolling or in the middle of cold rolling. When the intermediate annealing is performed, the cold rolling reduction (70 to 93%) is the rolling reduction in the cold rolling after the intermediate annealing.

  The cold-rolled aluminum alloy sheet is coated with an organic resin film on one or both sides, and is baked. The ultimate temperature of the plate material in painting baking is preferably 230 to 270 ° C., and the rate of temperature rise to the ultimate temperature is preferably 10 ° C./s or more.

  If the coating baking temperature is less than 230 ° C., the temperature at which the paint is baked is too low, and a predetermined coating film performance cannot be obtained. When the temperature exceeds 270 ° C., the recovery of the metal material proceeds too much, and the same problem as when the temperature rising rate is too slow occurs. When the coating baking temperature rise rate is less than 10 ° C./s, the time for holding at a high temperature becomes long, so the dislocation density introduced by cold rolling becomes too low due to recovery, resulting in low proof stress and bulge pressure. It becomes difficult to ensure.

  Examples of the present invention will be described below in comparison with comparative examples to demonstrate the effects. In addition, these Examples show one embodiment of this invention, and this invention is not limited to these.

Example 1 and Comparative Example 1
An aluminum alloy having the composition shown in Table 1 was ingot-formed by semi-continuous casting, and the resulting ingot was hot-rolled by homogenizing heat treatment at a temperature of 500 ° C. for 4 hours. In the hot rolling, the hot rough rolling was finished at 470 ° C., and the hot finish rolling was finished at 330 ° C. Subsequently, it was cold-rolled and subjected to intermediate annealing so that the material temperature reached 450 ° C. in a continuous annealing line to obtain a recrystallized structure. In Table 1, those outside the conditions of the present invention are underlined.

  Then, it cold-rolled to the product board thickness (Table 1). Cold rolling was controlled so that the material temperature for each pass was 120 to 150 ° C. Moreover, the plate | board thickness at the time of intermediate annealing was adjusted so that the cold rolling rate after intermediate annealing might be set to 75%.

  A cold-rolled sheet is coated with water-based paint on both sides of the cold-rolled sheet in a continuous processing line, and coating baking is performed within a temperature increase rate of 11 to 15 ° C / s, and the maximum temperature reached 250 ° C. The epoxy-acrylic-phenolic resin was coated in a controlled manner.

  Using the aluminum alloy plate (product plate) coated and baked with the resin as a test material, the following methods were used to evaluate the tensile strength, yield strength, formability, bulge pressure, pressure resistance, and openability (can openability). did. The evaluation results are shown in Table 2.

Tensile strength and proof stress in three directions: After removing the resin from the sulfuric acid film from the product plate, a tensile test piece having a distance between the gauge points of 50 mm and a parallel part width of 25 mm is formed, and the direction is 0, 45, 90 ° with respect to the rolling direction. Tensile tests were performed to measure proof stress and tensile strength. At this time, the minimum value among the values of the proof stress and the tensile strength in the three directions was obtained, and the difference between them was displayed as “difference”.
Formability: When a rivet cracks in the process of making a lid, the formability is determined to be rejected (x), and bulge pressure, pressure resistance measurement and openability evaluation cannot be performed. .
Bulge pressure: After forming a 204-diameter end from the product plate, winding it around the can body, increasing the internal pressure of the can at a pressure increase rate of 10 kPa / s by air pressure, and measuring the internal pressure when the tab nose position reaches the seam band position And bulge pressure. A bulge pressure of 480 kPa or higher was accepted (◯) and less than 480 kPa was rejected (x).

Pressure resistance: Like the bulge pressure, the internal pressure of the can is increased by air pressure at a pressure increase rate of 25 kPa / s, and the internal pressure when buckling is measured. did.
Openness: After making the lid, the tab was raised and opened, and the one opened along the groove in the opening was passed (◯), and the one derailed from the groove was rejected (x).

  As can be seen from Table 2, the test materials E1 to E6 according to the present invention are different from each other in the difference between the minimum value of the proof stress in three directions and the minimum value of the tensile strength in the range of 30 to 65 MPa. It had bulge pressure, pressure resistance and openness.

  On the other hand, since the test material C1 had a small amount of Mg, the tensile strength was low and the pressure resistance was inferior. Since the test material C2 has a small amount of Mn, the opening property is inferior, and the test material C3 has a large amount of Mn, so the moldability is poor. Since the test material C4 has a large amount of Si and the test material C5 has a large amount of Fe, all of them have poor moldability. Since the test material C6 has a large amount of Cu, the test material C7 has a large amount of Cr, the test material C8 has a large amount of Zn, and the test material C9 has a large amount of Ti.

Example 2 and Comparative Example 2
Using the ingot having the composition of E1 in Table 1, a product plate was produced under the conditions shown in Table 3, and performance evaluation was performed in the same manner as in Example 1 using the product plate as a test material. The evaluation results are shown in Table 4. In Tables 3 and 4, those outside the conditions of the present invention are underlined.

  As shown in Table 4, all of the test materials P1 to P3 according to the present invention have a difference between the minimum value of the proof stress in three directions and the minimum value of the tensile strength in the range of 30 to 65 MPa, and good moldability, It had bulge pressure, pressure resistance and openness.

  On the other hand, since the test material Q1 has a low end temperature of hot finish rolling, the variation in strength in the three directions is large, and the difference between the minimum value of the proof stress and the minimum value of the tensile strength in the three directions is small. Moreover, the moldability was inferior. Since test material Q2 had a low rolling reduction in cold rolling, the yield strength was low with respect to tensile strength, and a good bulge pressure could not be obtained. Since test material Q3 had a large cold rolling reduction, the difference between the proof stress and the tensile strength was reduced, and the formability was lowered. The test material Q4 had a high end temperature for cold rolling, so the yield strength was low, and a good bulge pressure could not be obtained.

  Since the test material Q5 had a low temperature increase rate at the time of coating baking, the proof stress was low and a good bulge pressure could not be obtained. Since test material Q6 had a high temperature at which coating baking was performed, the proof stress was low and a good bulge pressure could not be obtained.

Claims (4)

Mg: 4.3-5.5% (mass%, the same shall apply hereinafter), Mn: 0.35-0.55%, Si: 0.04-0.30%, Fe: 0.12-0.40% An aluminum alloy plate having a thickness of 0.20 to 0.25 mm, further comprising Cu, Cr, Zn, Ti each containing 0.10% or less, and the balance consisting of Al and inevitable impurities, One side or both sides are coated with an organic resin film, and the minimum value of the proof stress and the tensile strength when the tensile test is performed in the 0 °, 45 °, and 90 ° directions with respect to the rolling direction of the aluminum alloy plate. The aluminum alloy plate for can ends, wherein the difference between the minimum values is 30 to 65 MPa. The aluminum alloy plate for a can end according to claim 1, wherein the thickness per one side of the organic resin film is 1 to 20 µm. A homogenization heat treatment step of holding the aluminum alloy ingot having the composition according to claim 1 at a temperature of 460 to 540 ° C for 2 to 24 hours, and hot rough rolling and hot rolling of the ingot subjected to the homogenization heat treatment. When performing the finish rolling, the hot rolling step is completed at a temperature range of 460 to 540 ° C, the hot finish rolling is terminated at a temperature range of 300 to 370 ° C, and a recrystallized structure is obtained. A cold rolling step of cold rolling in a temperature range of 180 ° C. and a rolling reduction of 70 to 93% to obtain a cold rolled plate having a thickness of 0.20 to 0.25 mm, and one side of the cold rolled plate Alternatively, when the organic resin film is coated and baked on both sides, it includes a coating baking step of baking at a temperature rising rate of 10 ° C./s or more after coating and a temperature at which the plate reaches 230 to 270 ° C. Manufacturing method of aluminum alloy plate for can end . After the hot rolling step or in the middle of the cold rolling step, intermediate annealing is performed, and after the intermediate annealing is performed, cold rolling is performed at a temperature range of room temperature to 180 ° C. and a reduction rate of 70 to 93%. Then, a cold rolling step for obtaining a cold rolled plate having a thickness of 0.20 to 0.25 mm, and after the cold rolling step, when the organic resin film is coated and baked on one side or both sides, 10 ° C./s after coating 4. The method for producing an aluminum alloy plate for can ends according to claim 3, further comprising a paint baking step in which baking is performed under the above-described temperature rise rate and a condition that the temperature reached by the plate is 230 to 270 ° C.