JP2953592B2 - Lid for aluminum can with stay-on tub method and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lid for aluminum cans, and more particularly to a lid for aluminum cans of the stainless tub type having high strength and excellent tearability.

[0002]

2. Description of the Related Art Generally, as a lid material for an aluminum can,
50 such as 5052 alloy, 5082 alloy, 5182 alloy, etc.
No. 00 alloy is used, especially for cans for beer and other carbonated drinks, that is, for cans to which internal pressure is applied, high strength of 300 N / mm ² or more in proof strength after baking coating. Is required, so 518 for such applications
Two alloys dominate.

On the other hand, recently, in order to facilitate the reuse (recycling) of aluminum cans, it has been considered that the can body and the can lid are made of an alloy having the same composition, that is, a so-called unialloy is used. It has been proposed to use an alloy based on 3004 alloy for both the cover material and the body material for unialloy. However, in the conventional cover material based on the 3004 alloy, it is possible to obtain a level equivalent to that of the 5182 alloy. It is difficult, and a high degree of cold working is required to obtain a strength level equivalent to that of the 5182 alloy. Therefore, there is a problem of moldability as a lid material, and thus it has not been put to practical use.

[0004]

As a conventional can opening method of a general beverage can, a tab attached to the can lid is pulled up so that the tab and a part of the can lid (a drinking part) are completely removed from the can. In many cases, the so-called pull-on tab system is separated, but recently, from the viewpoint of environmental problems, the tab 2 attached to the can lid upper surface 1 and the can opening 3 of the can lid as shown in FIGS. There is an increasing tendency to employ a so-called suite-on-tub method that is not completely separated from the can. Also, as already mentioned, the tendency to collect and redissolve used cans and re-use them for recycling aluminum materials is increasing. It is becoming increasingly desirable to develop possible strategies.

By the way, in the pull-on tab type can, by pulling up the tab, the score is directly torn off from the score (notched portion serving as a cut line) by the force of a human finger. As shown in FIGS. 2 and 3, the attachment portion (rivet portion) 5 of the tab 2 is not pulled directly from the score 4 by pulling the handle 2 </ b> A of the tab 2 but pulling the handle 2 </ b> A. The tip 2 of the tab 2 by the action of a lever as a fulcrum
B is lowered, thereby pushing down the spout portion 3 and tearing the spout portion 3 away from the score 4 leaving a part.

As described above, in the stay-on tub system, since the force of the fingers is indirectly used by the action of the lever, the way of applying the force should be such that the mouth portion is smoothly torn from the score when the can is opened. The mouth part 3 cannot be torn evenly from the score 4 depending on how the force is applied, so that the opening of the can may fail. Such a problem can be improved to some extent by the shape and strength of the tab, or the notch size and shape of the score, but from the viewpoint of the material, a material that requires a small tearing force when opening the can, that is, It is desired to develop a material having good tearability.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a lid material used in a stainless steel tub type aluminum can which has high strength, good tearability, and is easy to recycle, and a method of manufacturing the same. It is intended to provide.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted various experiments and studies to solve the above-mentioned problems, and as a result, have found that the components are relatively similar to the 3004 alloy used for the body material. By appropriately setting the composition and appropriately adjusting the dispersion state of the intermetallic compound in the final sheet, it is a component system having high strength and good tearability, and relatively close to the body material. The present inventors have found that a lid material that can be easily recycled is obtained, and have accomplished the present invention.

More specifically, the lid material for a stainless steel tub type aluminum can according to the first aspect of the present invention is characterized in that:
3.0wt%, Cu0.05 ~ 0.7wt%, Si0.05 ~ 0.5wt%,
Mn contains 0.5 to 1.7 wt% and Fe 0.1 to 1.0 wt%, and the total amount of Mn and Fe is in the range of 1.0 to 2.0 wt%, and the balance consists of Al and unavoidable impurities. The number of intermetallic compounds of 1.0 μm or more is in the range of 500 to 3000 per 0.2 mm ² , the average diameter of intermetallic compounds on the surface is in the range of 2 to 6 μm, and 180 to 400 ° C. × 5. The minimum proof strength is 300 among the proof strength values in each direction in the plane after baking coating processing for ~ 1800 sec.
N / mm ² or more.

[0010] The method of manufacturing a lid member for a stainless steel tub type aluminum can according to the second aspect of the present invention is characterized in that:
%, Cu 0.05-0.7 wt%, Si 0.05-0.5 wt%, Mn
0.5 to 1.7 wt%, Fe 0.1 to 1.0 wt%, and Mn
The total amount of Fe and Fe is in the range of 1.0 to 2.0 wt%, and the balance is made of an alloy consisting of Al and unavoidable impurities by DC casting, then heating the ingot and rolling it to obtain an intermediate sheet thickness. At a heating rate of 1 ° C / sec or more.
Heated at a temperature within the range of ~ 620 ° C and no holding or 2
After holding for not more than 1 minute, perform intermediate annealing to cool at a high temperature rate of 1 ° C / sec or more, and then apply cold rolling to the final sheet thickness, whereby the number of intermetallic compounds of 1 μm or more on the surface per 0.2 mm ² The average diameter of the intermetallic compound on the surface is in the range of 500 to 3000
m, and 180 ~ 400 ℃ × 5 ~ 1800s
It is characterized in that a lid material having a minimum proof strength of 300 N / mm ² or more among proof strength values in each direction in a plane in a state where ec has been subjected to the baking coating treatment is obtained.

[0011]

First, the reasons for limiting the component composition range of the lid material according to the present invention will be described.

Mg: Mg coexists with Cu and Si to form M
In addition to contributing to age hardening due to precipitation of g ₂ Si and Al ₂ CuMg, Mg itself also contributes to solid solution strengthening. M
If the g amount is less than 1.0 wt%, the strength required for the lid material cannot be obtained. On the other hand, if the Mg content exceeds 3.0% by weight, strength improvement can be expected, but the Mg content in the ingot (recycled ingot) after the recovered aluminum two-piece can is redissolved for recycling increases, In the case of manufacturing a 3000-series body material from a lump, pure aluminum metal is required to dilute the Mg concentration, achieving one of the objects of the present invention, the ease of recycling. become unable.
Therefore, the amount of Mg was set in the range of 1.0 to 3.0 wt%.

Cu: Cu itself contributes to solid solution strengthening in the same manner as Mg, and Al ₂ C coexists with Mg.
It contributes to age hardening due to the precipitation of uMg, and particularly in applications where baking coating is used as in the present invention, the above-mentioned effect is large, and a material having high strength after baking coating can be obtained. If the Cu content is less than 0.05 wt%, the effect is small,
If it exceeds 0.7 wt%, age hardening can be easily obtained, but it becomes too hard and disadvantageous for subsequent molding.

Si: Si is Mg ₂ S due to coexistence with Mg.
Precipitates i and contributes to age hardening, but in the case of the present invention, rather contributes to obtaining an appropriate dispersion state of the intermetallic compound in the presence of Fe and Mn. Si
If the amount is less than 0.05 wt%, the effect is small, while 0.5 wt%
If the ratio exceeds 1, the effect is saturated, and age hardening by Mg ₂ Si becomes excessive or solid solution hardening by Si itself progresses to deteriorate the formability. Therefore, the amount of Si is 0.05-
It was within the range of 0.5 wt%.

Mn: Mn not only contributes to the improvement of strength, but is also an essential element for producing an intermetallic compound in the present invention, and plays an important role together with Fe for obtaining an appropriate intermetallic compound dispersion state. Fulfill. In the case of the DC casting method mainly applied in the present invention, the Mn content is 1.7 wt.
%, A primary intercrystalline giant intermetallic compound of MnAl ₆ is formed, which significantly impairs formability. On the other hand, Mn content is 0.5wt%
If it is less than 3, it becomes difficult to secure an amount of the intermetallic compound sufficient to obtain a necessary intermetallic compound dispersion state. Therefore, the Mn content is set in the range of 0.5 to 1.7 wt%.

Fe: Fe is an element necessary for obtaining an appropriate intermetallic compound dispersion state together with Mn.
Like Si, it is an element that promotes crystallization of Mn. Fe
If the amount is less than 0.1 wt%, the effect is small, while 1.0 wt%
If the ratio exceeds the above range, a primary crystal giant intermetallic compound is formed in combination with the addition of Mn, and the formability is impaired. Therefore, the amount of Fe is 0.1 ~
It was within the range of 1.0 wt%.

Mn + Fe: The amount of Mn and the amount of Fe are individually as described above, but both need to coexist for the formation of the intermetallic compound. In order to obtain an appropriate dispersion state, it is necessary to consider the total content of both. If the total amount of Mn + Fe is less than 1.0% by weight, an appropriate dispersion state of the intermetallic compound cannot be obtained, while if the total amount exceeds 2.0% by weight, a primary crystal intermetallic compound is formed to deteriorate the formability. So Mn +
The total amount of Fe was in the range of 1.0 to 2.0 wt%.

In a usual aluminum alloy,
In order to refine the ingot crystal grains, a small amount of Ti alone or Ti may be added in combination with B. In the present invention, the addition of a small amount of Ti or Ti and B is acceptable. However, if Ti is added in an amount of less than 0.01 wt%, the effect of refining ingot crystal grains cannot be obtained, while 0.3 wt%
If it exceeds the limit, the formability will be impaired.
Is preferably within the range. When B is added together with Ti, the effect is not obtained if B is less than 1 ppm.
If it exceeds 500 ppm, the moldability is impaired, so that B is preferably within the range of 1 to 500 ppm.

In addition, if each of Cr, Zr, and V is up to about 0.3% by weight, the effects of the present invention are contributed to the improvement of strength without losing the effect. Further, when Zn is also up to about 0.5 wt%, it contributes to the improvement of strength without losing the effect of the present invention.

Here, the alloy composition of the lid material specified in the present invention is the composition composition of the 3004 alloy (Mg 0.8-1.3 wt%, Mn 1.
0 to 1.5 wt%, Si 0.30 wt% or less, Fe 0.7 wt% or less, C
u 0.25 wt% or less, the balance being close to Al). Therefore, a two-piece can is made by combining the lid material of the present invention and a body material made of a conventional general 3004 alloy, and the can is collected and recycled again for recycling, and the ingot (recycled ingot) )), If the same lid material and body material are to be manufactured again, the loss of Mg due to oxidation during re-dissolution (Mg is reduced by about 20%) is expected.
Need only be added, and therefore it is not necessary to add new aluminum ingots, so that recycling is easy. Incidentally, even when the lid material and the body material are made of exactly the same alloy and made into a unialloy, it is usual to add new Mg due to the loss of Mg at the time of re-melting. It can be said that the ease of recycling when the lid material within the range is used is equivalent to the case of the unialloy.

In the lid material of the present invention, not only the alloy composition is regulated as described above, but also the dispersion state of the intermetallic compound is appropriately adjusted, and the proof stress after baking coating is appropriately secured. Very important. That is, as shown in FIG. 4, the present inventors applied a load (tearing force) to an aluminum alloy plate 10 having a width W of 40 mm and a thickness T of 0.3 mm.
A test was conducted to evaluate the tearing property by adding the above and below, and in order to obtain excellent tearing property without impairing the formability, the number of intermetallic compounds having a diameter of 1 μm or It is necessary that the average diameter of the intermetallic compound having a size of 500 to 3000 per 0.2 mm ² and 1 μm or more is within a range of 2 to 6 μm,
It is also excellent that the proof strength in the direction where the proof strength is the lowest among the proof strengths in each direction in the plane is 300 N / mm ² or more in the proof strength value after baking coating treatment at 180 to 400 ° C. × 5 to 1800 sec. Was found to be necessary in order to obtain a good tearability.

The larger the number of intermetallic compounds on the plate surface and the larger the diameter of the intermetallic compounds, the better the tearability. The number of intermetallic compounds of 1 μm or more is 0.2 mm ²
If the number is less than 500 pieces per piece, the desired tearing property cannot be obtained in the present invention, and even if the average diameter of the intermetallic compound is less than 2 μm, the desired tearing property cannot be obtained. However, if the number of intermetallic compounds of 1 μm or more exceeds 3000 per 0.2 mm ^2, or if the average diameter exceeds 6 μm, the material becomes brittle and problems arise in molding. Therefore, the dispersion state of the intermetallic compound is defined as described above. The average diameter of the intermetallic compound is as follows for an intermetallic compound having a major axis of 1 μm or more.
The sum of the major axes of the intermetallic compounds is reduced by the number of intermetallic compounds.

On the other hand, with respect to the proof stress, when the thin plate is to be torn, the higher the proof stress value, the smaller the load required for the tear. That is, FIG. 5 is an enlarged view of the state of the tear progress portion 11 in the tear property test shown in FIG. 4 described above. The depth L of the tear progress portion 11 up to the tear crack tip 11A increases as the proof stress increases. In addition, the greater the depth L, the smaller the apparent tearing force. Therefore, the greater the proof strength of the plate, the smaller the force required for tearing, and the better the tearability.

In the tearing test shown in FIG. 4 described above, each of the lid material satisfying the component composition conditions and the intermetallic compound dispersion conditions specified in the present invention and each of the conventional 5182 alloy, 5082 alloy, and 5052 alloy were hardened. FIG. 6 shows the results of examining the tearing force of the conventional lid member made of a plate with various proof stress values (provided that the proof stress value in the in-plane rolling direction) was varied.

As is apparent from FIG. 6, the lid material of the present invention in which the dispersion state of the intermetallic compound is within the range defined by the present invention is as follows.
As compared with a conventional lid material (a hard plate made of a 5182 alloy or the like), the tearing force is reduced by about 20% with the same strength (proof stress) and the same plate thickness. Further, it can be seen that the tearing force of the same material decreases as the proof stress increases, and that the tearing force is sufficiently reduced particularly when the proof stress is 300 N / mm ² or more. As described above, by appropriately setting the conditions of the intermetallic compound and increasing the proof stress to 300 N / mm ² or more, it is possible to tear with a small tearing force, and the tearing property is improved.

Here, the rolled sheet usually has a strength difference in each direction within the plane, and generally, the L direction (rolling direction), the C direction (direction perpendicular to the rolling direction) and the 45 direction in the plane.
The 45 ° direction has the lowest strength among the ° directions (directions of 45 ° in the L direction and C direction). Since the direction of the score line always includes the 45 ° direction in the stay-ion tub type can lid, in order to obtain good tearability over the entire length of the score, in the present invention, the direction with the lowest proof stress value (usually 45 °) is used.
Direction), it is specified that the material has a proof stress of 300 N / mm ² or more in the direction of the lowest proof stress value so that good tearability can be obtained.

Further, the proof stress value in the in-plane proof strength minimum direction is set to 3
The definition of 00 N / mm ² or more also has the following meaning.

That is, in applications where internal pressure is applied, such as beer and carbonated beverages, it is generally required that the can material has a high strength, and in view of the recent tendency of the can body to be thinner, a higher strength can material is required. Is required. As described above, a rolled plate usually has a strength difference depending on each in-plane direction.In general, the strength is the lowest in the 45 ° direction.
Begin swelling from the ° direction. Therefore, among the proof stress values in each direction in the plane, it is required to improve the proof stress value in the direction of the lowest proof stress. However, by setting the proof stress value in the lowest proof stress direction to 300 N / mm ² or more, sufficient reduction in thickness is possible. Can respond.

In the stay-on tub system, as described above, the tip of the tub presses the drinking portion inside the score by the action of the lever with the rivet as a fulcrum, and tears off the score. At this time, the higher the strength of the lid material, the less the force is absorbed by the deformation of the material between the pressed portion by the tab and the score, and as a result, the force is easily applied to the score portion. Therefore, from this point as well, the higher the strength, the better the tearability.

Next, the manufacturing process of the lid member according to the present invention will be described.

First, an aluminum alloy ingot having the above component composition is cast by a DC casting method (semi-continuous casting method). At the time of this casting, in order to obtain the dispersion state of the intermetallic compound specified in the present invention, the cooling rate is set to 1
It is preferable that the temperature be in the range of about 30 ° C./sec. If the cooling rate is slower than this range, the intermetallic compound becomes coarse, and if it is slower than this range, the intermetallic compound becomes too fine, and it is difficult to obtain the target dispersion state and size in the final plate.

Next, the ingot is subjected to heating as a homogenization treatment, and then subjected to preheating before hot rolling or preheating before hot rolling also serving as a homogenization treatment. Such ingot heating may be performed at a temperature in the range of 460 to 630 ° C. for about 1 hour to 24 hours according to a conventional method.

After the ingot is heated, hot rolling is performed. In this hot rolling, the rising temperature is 250 mm or less when the rising thickness is about 10 mm or less.
If the temperature is within the range of about 350 ° C., the subsequent properties are not adversely affected.

After the hot rolling, intermediate annealing is immediately performed, or primary cold rolling is performed to obtain an intermediate sheet thickness.
Intermediate annealing is performed. In this intermediate annealing, heating is performed at a temperature rising rate of 1 ° C./sec or more to a temperature in the range of 450 to 620 ° C., and holding is performed for 120 seconds or less at a temperature in the range (including the case where no holding is performed). It is necessary to cool at a cooling rate of 1 ° C / sec or more. Such conditions can generally be achieved by annealing using a continuous annealing furnace. The reason for setting the intermediate annealing conditions in this way is as follows.

That is, when the temperature is raised and lowered at a rate of less than 1 ° C./sec, as in the annealing using the conventional box-type annealing furnace, the solid solution amount of Mn obtained in the hot-rolled state is reduced, C
Even if the solid solution amount of elements such as u, Mg, and Si is reduced and the final cold rolling reduction is increased to about 90%, it is difficult to obtain sufficient strength. On the other hand, by setting the heating rate and the cooling rate at 1 ° C./sec or more and the heating temperature at 450 to 620 ° C., the solid solution amount of Mn can be maintained, and Cu, M
As the solid solution of g, Si and the like progresses, the material subjected to the baking coating process, such as the material targeted in the present invention, has less softening due to the baking coating process, so that sufficient strength can be obtained as the strength after the baking coating. Become. If the heating temperature is lower than 450 ° C, it is difficult to obtain sufficient strength.
If it exceeds, local melting may occur. Also
If the holding time at 450 to 620 ° C. exceeds 120 seconds, the oxidation of the surface proceeds, which causes a problem in appearance.

After the intermediate annealing as described above, final cold rolling is performed to the product sheet thickness. If the cold rolling reduction at this time is 30% or more, the required high strength can be obtained by appropriately selecting the component composition and other process conditions.

The rolled sheet having the final thickness obtained by the final cold rolling may be directly used as a lid material for a can lid, but at a temperature in the range of 100 to 200 ° C. for about 30 minutes to 10 hours. When the final annealing is performed, aging precipitation is promoted, and a decrease in strength in baking coating can be reduced, and a lid material having higher strength can be obtained even with the same component composition and the same manufacturing process conditions. In addition, since the strength is improved by the final annealing as described above, the final cold rolling reduction can be reduced even if the final strength is the same, so that the formability and ear ratio are improved.

In the baking coating process, it is generally 180 to 400 ° C.
For about 5 to 1800 sec. Therefore, in the present invention, the proof strength value of the cover material in the lowest proof strength direction (300 N / mm ²
The above is defined as the yield strength after a paint baking treatment at 180 to 450 ° C. × 5 to 1800 sec.

[0039]

EXAMPLES DC casting of alloys A, B, and C in Table 1 was carried out according to a conventional method, and each obtained ingot was subjected to ingot heating and hot rolling according to a conventional method. Some of the hot-rolled sheets are subjected to primary cold rolling,
Some of them were subjected to intermediate annealing without primary cold rolling. Furthermore, final cold rolling is performed to make the final sheet thickness,
Some were subjected to final annealing. Main process conditions are shown in production numbers 1 to 4 in Table 2. When a continuous annealing furnace is used as the intermediate annealing, both the rate of temperature rise and the rate of temperature fall satisfy the condition of 1 ° C./sec or more specified in the present invention.

For each of the obtained lid materials, 1 μm
The number of intermetallic compounds having the above diameter (per 0.2 mm ² ) was examined, and the average diameter of intermetallic compounds having a diameter of 1 μm or more on the plate surface was also examined. The results are shown in Table 2.

Further, each lid material is subjected to a heat treatment of 270 ° C. × 20 sec corresponding to continuous annealing coating, and each in-plane direction (L direction, C direction, 45 °) after the heat treatment equivalent to baking coating.
Direction) and the tear force (tearing load) when tearing along the L direction by the method of FIG. 4 already described. Table 3 shows the minimum proof stress value (although all the proof stress values were in the 45 ° direction) among the proof stress values in the in-plane directions, and the tearing force. Table 3 also shows the results of checking the lid forming properties of each lid material. In this case, an experiment was conducted in which 10,000 pieces were covered, and a circle mark was given when the occurrence of defects was zero.

[0042]

[Table 1]

[0043]

[Table 2]

[0044]

[Table 3]

In Tables 1 to 3, the lids obtained by Production No. 1 and Production No. 2 are alloys whose alloy component composition is within the range of the present invention, and the manufacturing process conditions are within the range specified by the present invention. As a result, the intermetallic compound dispersion state and the proof strength value in the lowest strength direction in the final plate were within the ranges specified in the present invention. In this case, the tearing force was small, the tearability was good, and the It turns out that a lid property is also favorable.

On the other hand, the lid material obtained by Production No. 3 was subjected to intermediate annealing, which was performed by a box-type annealing furnace having a low heating rate and a low cooling rate and a low heating temperature. In this case, the components of the present invention were used. Although an attempt was made to increase the strength by using a relatively high Mg content in the composition range and increasing the cold rolling reduction relatively, the proof stress value in the lowest proof stress direction is specified by the present invention.
It did not exceed 0 N / mm ² .

The lid material according to the production number 4 uses the 5182 alloy which has been conventionally used for the lid material.
In this case, the number of intermetallic compounds in the final plate was small, and the tearability was poor.

[0048]

As is clear from the above description, the lid material of the present invention has excellent tearability and can be easily torn with a small tearing force. The spout portion can be torn uniformly and easily from the score, there is little risk of failure to open the can, and the strength after baking is high, so that it can sufficiently cope with the thinning of the can body. In addition, the composition of the lid material of the present invention has been frequently used for the body material.
Since it is close to alloy 04, it can be easily recycled by combining with alloy body 3004.

Further, according to the method for manufacturing a lid member of the present invention, a lid member having the above-described excellent characteristics can be actually manufactured.

[Brief description of the drawings]

FIG. 1 is a plan view showing an upper surface of a can lid in a stay-tub type can.

FIG. 2 is a vertical cross-sectional view of the upper surface of a can lid of a stay-ion tub type can, that is, a vertical cross-sectional view taken along line AA of FIG.

FIG. 3 is a longitudinal sectional view corresponding to FIG. 2, showing a state of an upper surface of a can lid when the can is opened in a stay tub type can.

FIG. 4 is a perspective view showing a state in which a tear test is performed.

FIG. 5 is a schematic diagram showing a magnified view of a tear portion in the tear test shown in FIG. 4;

FIG. 6 is a graph showing a relationship between a proof stress value and a tearing force of a material according to the tearing test shown in FIG.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-301183 (JP, A) JP-A-61-64847 (JP, A) JP-A 1-247544 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) C22C 21/00-21/18

Claims (2)

(57) [Claims] 1. Mg 1.0 to 3.0 wt%, Cu 0.05 to 0.7 wt%
%, Si 0.05-0.5wt%, Mn 0.5-1.7wt%, Fe
0.1 to 1.0 wt%, and the total amount of Mn and Fe is
1.0 to 2.0 wt%, the balance being Al and unavoidable impurities, the number of intermetallic compounds of 1.0 μm or more on the surface is in the range of 500 to 3000 per 0.2 mm ² , and The average diameter of the intermetallic compound is 2
~ 6μm, 180 ~ 400 ℃ × 5-1
A lid material for a stainless steel tub type aluminum can, characterized in that the minimum proof strength among the proof strength values in each direction in the plane after the baking coating treatment for 800 sec is 300 N / mm ² or more. 2. Mg 1.0 to 3.0 wt%, Cu 0.05 to 0.7 wt%
%, Si 0.05-0.5wt%, Mn 0.5-1.7wt%, Fe
0.1 to 1.0 wt%, and the total amount of Mn and Fe is
An alloy in the range of 1.0 to 2.0 wt%, with the balance being Al and unavoidable impurities, is cast by a DC casting method, then subjected to ingot heating and then rolled to an intermediate plate thickness, and further 1 ° C / sec. Heated at a temperature within the range of 450 to 620 ° C at the above temperature rise rate, without holding, or after holding within 2 minutes 1 ° C
Intermediate annealing at a cooling rate of at least / sec or more is performed, and then cold rolling is performed to a final sheet thickness, whereby the number of intermetallic compounds of 1 µm or more on the surface is in the range of 500 to 3000 per 0.2 mm ² . And the average diameter of the intermetallic compound on the surface is in the range of 2 to 6 μm, and among the proof stress values in each of the in-plane directions when baking coating treatment is performed at 180 to 400 ° C. and 5 to 1800 sec. Minimum proof stress
Characterized by obtaining a lid material of 300 N / mm ² or more,
A method for manufacturing a lid member for a stainless steel tub type aluminum can.