JPH0949043A - Rolled aluminum alloy sheet for forming, excellent in ironing property - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve ironing property and to prevent the occurrence of galling by embedding fine solid lubricants in the surface of an Al and an Al alloy sheet and improving the lubricity of the surface. SOLUTION: After solid lubricants of 0.1-50μm average grain size, e.g. Mo2 , WS2 , graphite, BN, (CF)n , metal oxide, such as PbO MoO3 and ZnO, fluoride such as CaF2 , NbF, and BaF2 , and Si3 N4 , are applied to respective surfaces of an industrial pure Al sheet and various Al alloy sheets, rolling is carried out, by which the solid lubricants are embedded in >=20% of the surface of the Al sheet and the Al alloy sheets into the state where at least a part of each solid lubricant is allowed to appear to the surface. The occurrence of flaw and deformation, that is, so-called galling in a direction nearly parallel to an ironing direction at the surface, causing deterioration in external appearance quality, can be prevented at the time of ironing these Al sheet and Al alloy sheets, and as a result, the Al sheet and the Al alloy sheets, excellent in formability, can be produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy plate which is less likely to cause galling during ironing, and more particularly to an aluminum alloy plate suitable as a can body. In the present invention, the aluminum alloy plate means an industrial pure aluminum plate and various aluminum alloy plates.

[0002]

2. Description of the Related Art Generally, drawing processing (Dra
Wing) and ironing (Ironing) are added (DI
(Processing and generic name), during the ironing process, scratches and discoloration, so-called galling, may occur on the surface of the material plate almost parallel to the ironing direction. This goring significantly deteriorates the quality of the surface of the material plate, and especially in the case where the aluminum base is exposed instead of coating the entire can body like an aluminum can, the occurrence of this goring does not occur. It is a fatal surface defect that significantly impairs the appearance of the product.

Further, the occurrence of goring causes damage to tools such as dies and shortens tool life. Further, if the goring is severe, troubles such as material breakage may occur during ironing, interrupting the work to reduce the work rate, and debris sometimes damages the ironing tool and the processing equipment.

From the above, it is strongly desired to suppress the occurrence of galling in the ironing process.

The mechanism of galling on an aluminum plate is that the ironing die is in direct contact with the surface of the aluminum alloy plate due to poor lubrication during ironing, and the aluminum alloy pieces and hard particles such as Al ₂ O ₃ are contained in the alloy plate. It is considered that it is caused by peeling from the surface and adhering to the ironing die, and the agglomerated mass rubbing the surface of the aluminum alloy plate. Therefore, various methods have been devised to suppress the occurrence of galling by improving lubrication as compared with the related art.

As to the lubricating oil to be applied, 1) as a pretreatment for ironing, a lubricating oil stock solution is applied to an aluminum alloy plate to perform re-oil treatment for improving lubricity. 2) Use various combinations of the composition ratio of the lubricating oil during ironing, and use a lubricating oil with an appropriate composition ratio that will not run out easily. 3) Adjust the roughness of the surface of the material plate to improve the oil retaining property by the unevenness of the surface of the plate. There is a method such as.

Further, it is also practiced to suppress the occurrence of galling by controlling the material characteristics such as the structure of the aluminum alloy plate. For example, AA3004 alloy is currently widely used for can body materials. One of the reasons is that it has relatively high strength, excellent formability, and relatively low work hardening during ironing. Although it can be said that it is excellent, a large amount of Al—Mn—Fe-based coarse crystallization compounds also exist, and this coarse crystallization compound exhibits solid lubricity, and due to the voids formed in the vicinity of the crystallization compound, the oil retaining property is improved. It is also one of the reasons why this alloy is adopted as a practical alloy because it is less likely to cause galling due to the effects such as improvement of the heat treatment and the effect of self-cleaning of the ironing die.

[0008]

As described above, various methods have been devised as a countermeasure against the galling, but the present situation is that they are not yet sufficient.

In the method using the lubricating oil, in the case of multi-step processing such as ironing with a large degree of processing such as can forming, which is performed several times in succession, although the lubricating property is shown in the first processing, the lubricating oil is increased as the processing progresses. Is peeled off and oil runs out.

A method of applying a solid lubricant to the surface of the plate instead of the lubricating oil has also been devised. However, although it is effective to process only once, in multi-step processing such as can forming, the lubricant applied in the first to second processing is stripped off, and the lubricant is applied in subsequent processing. There is a problem that shortage occurs and goring occurs.

Further, even in the method of improving the material characteristics by devising the manufacturing conditions of the plate so as to have the characteristics such as the structure in which the galling is unlikely to occur, the manufacturing conditions for forming the specific structure become complicated and the cost becomes high. There are problems that the condition range is narrow and advanced technology is required for manufacturing. Further, when the degree of processing is large, sufficient galling resistance cannot be obtained only by improving the characteristics of the material.

[0012] Further, a uni-alloying method in which a can lid material and a can body material are made of the same alloy, which has been conventionally made of different alloy materials, has been studied from the viewpoint of productivity and recyclability. The limited methods of improving ironing workability prevent this uni-alloying. Therefore, there has been a demand for a method for improving ironing workability other than improving the alloy components and properties of the material itself.

In view of the above problems, the present invention improves the ironing workability by suppressing the occurrence of galling in the current aluminum alloy plate for a can body and the aluminum alloy plate of the high strength material or the like which is currently poor in the ironing workability. By supplying materials suitable for DI processed can body materials suitable for high strength thinning and suppressing the formation of coagulated lumps in dies during DI processing, the die screening interval is extended and the work rate is improved. In addition, the purpose is to extend the life of tools such as dies.

[0014]

According to the present invention, a means for solving the problem is to embed a solid lubricant on the surface of a plate to improve the lubricity of the surface of the plate, thereby improving the workability of the plate, especially ironing. It is intended to improve workability and suppress the occurrence of goring.

That is, in the present invention, a solid lubricant having an average particle diameter of 0.1 to 50 μm is embedded in the plate surface in an area ratio of 20% or more, and at least a part of the solid lubricant is exposed on the plate surface. It is an aluminum alloy rolled plate for forming, which is excellent in ironing workability, and is coated with a solid lubricant having an average particle size of 0.1 to 50 μm on the plate surface, and then rolled. A method for producing a rolled aluminum alloy plate for forming, which is excellent in ironing workability, characterized in that a solid lubricant is embedded on the surface in an area ratio of 20% or more.

As the solid lubricant to be used, those generally used may be used, but typical ones include molybdenum disulfide, tungsten disulfide, graphite, boron nitride, graphite fluoride (CF) _n , metal oxide ( Examples thereof include lead oxide, molybdenum oxide, zinc oxide, etc.), fluorides (calcium fluoride, barium fluoride, sodium fluoride, etc.), silicon nitride, and mixtures of two or more of these solid lubricants.

The average particle size of the solid lubricant used is 0.1
It is 50 μm. If it is less than 0.1 μm, the coefficient of friction becomes large, and if it exceeds 50 μm, the load bearing performance deteriorates.

The amount of the solid lubricant to be embedded must be such that the area ratio of the solid lubricant on the plate surface is 20% or more. If it is less than 20%, a sufficient lubricating effect cannot be obtained for the newly formed surface produced by processing.
The upper limit of the area ratio is not particularly limited, but it is determined by the plate thickness during hot rolling for forming the surface lubricating layer in the treatment and the cold rolling ratio thereafter. The area ratio in the final plate is determined by the dispersion of the initial surface lubrication layer and the formation of the newly formed surface by cold rolling. Generally, 20% or more of cold rolling is generally performed, so that the area ratio of the solid lubricant is 80% or less.

In the present invention, it is important that a part of the solid lubricant is exposed on the surface of the plate, and if the solid lubricant is completely buried inside the aluminum alloy plate, galling prevention and ironing are not performed. The effect of improving the sex is lost.

The depth of the plate surface layer in which the solid lubricant is embedded may be determined according to the plate thickness of the aluminum alloy plate and the working ratio such as the ironing ratio, but 0.1 to 1 from the plate surface.
A depth of 50 μm is suitable. That is, it is necessary that the solid lubricant is distributed to a depth of about one layer, and it is effective that the solid lubricant is embedded to the inside of the plate. 0.
If the solid lubricant is present only in the range of less than 1 μm, the amount is too small to produce a solid lubricating effect, and it is easy to be buried or peeled off. On the other hand, a sufficient lubrication effect cannot be obtained. Further, even if the depth is set to exceed 150 μm, further improvement in performance cannot be expected. However, especially when performing strong working or multiple times of working, it is better to distribute deeply because the solid lubricant in the vicinity of the surface will be deprived of the deep working solid lubricant instead of being exposed to the surface. preferable.

As a method for producing an aluminum alloy plate according to claim 1, the solid lubricant is applied to the surface of the aluminum alloy plate as described in claim 2 and then the solid lubricant is applied to the plate surface by rolling. The embedding method is raised.

In order to apply the solid lubricant to the surface of the plate, it is preferable to apply the solid lubricant as it is or to disperse it in a dispersion medium such as a liquid into a colloidal state with a brush, a roll coater or the like, or spray it with a spray. Since the solid lubricant is rolled immediately after it is applied, it is not necessary to firmly adhere it, but it is important to apply it uniformly over the entire surface.

In the rolling after the coating, the solid lubricant can be embedded in the surface of the aluminum alloy plate if the rolling ratio is 3% or more. Therefore, it may be carried out in either the hot rolling or the cold rolling in the usual aluminum alloy sheet manufacturing process. However, if it is carried out too much in the upstream process, the plate surface area will increase due to the subsequent rolling, and as a result, the final area ratio of the solid lubricant may be less than 20%. In this case, it is desirable to set the area ratio of the solid lubricant at the time of application to be high.

[0024]

[Operation] The mechanism of the occurrence of galling on the aluminum plate is (1) direct contact between the surface of the aluminum alloy plate and the ironing die due to poor lubrication such as oil film breakage during ironing, and aluminum alloy pieces sticking to the die,
(2) The hard particles of oxides such as Al ₂ O ₃ and MgO and the fine intermetallic compounds such as Al (Mn, Fe) Si formed on the surface of the aluminum alloy plate are peeled from the surface where they are adhered to the ironing die. It is considered that the coagulated lumps formed by doing so and the like rub against the surface of the aluminum alloy plate.

On the other hand, in the aluminum alloy plate according to the present invention, a solid lubricant is embedded in the surface layer of the plate to prevent direct contact between the aluminum alloy itself and the die surface to reduce friction and to reduce the surface of the aluminum alloy plate. It is possible to prevent the oxides and the like generated in the above from being peeled off by the die, and as a result, it is possible to prevent the occurrence of galling and the adhesion of aluminum alloy pieces, oxides and intermetallic compounds to the die.

Moreover, in the processing such as the multi-step ironing which involves a remarkable reduction of the plate thickness and the formation of a newly formed surface, only by applying the conventional solid lubricant, the lubricating effect is lowered during the processing and a sufficient effect is obtained. However, according to the aluminum alloy plate of the present invention, since the solid lubricant is embedded in the plate surface, the lubricant is stripped from the plate surface even if the plate thickness is significantly reduced or a new surface is formed. Because it is never taken,
A sufficient lubrication effect is obtained even in multi-step ironing, and no galling occurs.

The above-mentioned action of the present invention can be further improved by using it together with a mineral lubricating oil, a vegetable lubricating oil, a synthetic lubricating oil or a mixed lubricating oil thereof.

[0028]

EXAMPLES Examples of the present invention will be described below.

The aluminum alloys used as test materials are JISA3004P, JISA5052P, and JISA5.
182P was used. The alloy component composition is shown in Table 1.

[0030]

[Table 1]

The surface lubricating layer was formed by the following method. I: At the time of hot rolling, a colloidal solid lubricant was spray-coated on the surface of the roll and the plate, and embedded in the plate surface by rolling. II: A solid lubricant was applied to the plate on which the surface lubricating layer was not formed before the pull-out test. -: The solid lubricant layer was not formed, and the test was performed as it was. The galling resistance was evaluated by making a test piece having a width of 10 mm and a length of 150 mm from each test material and performing a pull-out test. In the drawing test, the drawing speed is 500 mm / min, assuming multi-step processing such as drawing-ironing.
The drawing process with a plate thickness reduction rate of 20% is performed twice consecutively, and 1
A mineral oil-based lubricating oil was applied only for the first time.

[Example 1] For Nos. 1 to 3, 3004 alloy was used to obtain an ingot having a plate thickness of 500 mm by DC casting. Next, the sheet thickness is 3.5 mm by hot rolling and 0.75 mm by cold rolling, intermediate annealing is performed by a continuous annealing furnace (CAL), and then the sheet thickness is 0.30 by cold rolling.
mm. Here, in the intermediate annealing, cooling was performed under the conditions of a heating rate of 20 ° C./s and a cooling rate of 20 ° C./s immediately after reaching the set temperature. For Nos. ₂ and 3, colloidal MoS ₂ was applied by spraying during hot rolling and rolled to form a surface lubricating layer. Using this test material, the pulling test was performed to evaluate the galling resistance.
Table 2 shows the production conditions and the results of evaluation of galling resistance.

[0033]

[Table 2]

As shown in the table, all of the DC materials of 3004 alloy have excellent galling resistance, so that all of them show extremely good performance. That is, it has been confirmed that when the present invention is applied to an alloy having excellent galling resistance, it exhibits the same or superior performance as the conventional material and does not deteriorate the performance.

[Embodiment 2] Embodiment No. 4 to which the present invention is applied, which uses the 5052 alloy, which is conventionally considered to be unusable for ironing due to severe occurrence of galling.
~ 12 are shown.

[0036]

[Table 3]

For Nos. 4, 5, 6 and 7, ingots having a thickness of 500 mm were obtained by DC casting. After that, it is hot rolled to 3.5 mm and cold rolled to 1.0 mm.
An O material was obtained by annealing at 0 ° C. × 2 hours. For Nos. 8 to 12, similarly, a 500 mm ingot obtained by DC casting was 3.5 mm by hot rolling and 0.75 mm by cold rolling.
And CAL intermediate annealing was performed at 500 ° C. Then, it cold-rolled to 0.3 mm and was set as the sample material. No4
For 5, 8, 10, 11, and 12, the initial surface lubricating layer was formed by hot rolling in the same manner as in Example 1.
Graphite was used as the solid lubricant. No. 7 was tested by applying colloidal graphite before the pull-out test. Inventive examples Nos. 4, 5 and 8 showed good galling resistance. In contrast, No6, 9
Is a comparative example using the conventional method using only lubricating oil, and strong galling occurred. No. 7 in which graphite was simply applied to the plate surface immediately before the pull-out test was effective at the first time, but galling occurred at the second time because the lubricant was stripped off by this pull-out process. No10
No, because the area ratio of the solid lubricant is less than 20%.
In 11, the average particle size of the solid lubricant graphite is 0.1
Since the average particle size of graphite was less than 50 μm because of the average particle size of No. 12 or less, no sufficient effect was obtained.

[Embodiment 3] Similarly, inferior ironing workability 5
The Example No. 13-21 which used 182 alloy is shown. 51
After obtaining an ingot with a thickness of 500 mm by DC casting using the No. 82 alloy, No. 13 to 17 were hot rolled to 3.5 mm and cold rolled to 0.60 mm. Here, intermediate annealing was performed at 320 ° C. for 2 hours and then cold rolling was performed to 0.3 mm. No. 18 to 21 are 5.0 mm by hot rolling and 1.0 mm by cold rolling.
And an O material was obtained by annealing at 320 ° C. for 2 hours. Boron nitride is used as the solid lubricant, and No. 13, 14, 1
The formation of the initial surface lubricating layers of Nos. 5, 17, 18 and 20 was performed during hot rolling. For Nos. 16, 19, and 21, the surface lubricating layer according to the present invention was not formed.

[0039]

[Table 4]

Nos. 13, 14, 15, and 18 are examples by the method of the present invention, and all showed good galling resistance. Nos. 16 and 19 are comparative examples in which only lubricating oil was used, and both of them caused oil shortage during processing, resulting in strong galling. In No. 17, the area ratio of the solid lubricant in the surface lubricating layer was smaller than 20%, and in No. 20, the average particle size of the solid lubricant was larger than 50 μm, so that neither sufficient effect was obtained. No. 21 was obtained by applying colloidal boron nitride to the plate before the pull-out test, and the test was effective in the first pull-out.
At this time, the solid lubricant was stripped off, and galling occurred in the second drawing.

[Embodiment 4] Similar to Embodiment 2, the case where the type of solid lubricant was changed with respect to the 5052 alloy and a case where a plurality of types of solid lubricants were mixed was examined. An ingot having a thickness of 500 mm was obtained by DC casting using the 5052 alloy.
Next, the thickness was 3.5 mm by hot rolling, and at the same time, an initial surface lubricating layer was formed with a solid lubricant. No. as a solid lubricant. 22 to 27 are molybdenum disulfide, No.
In 28 to 32, a mixture of molybdenum disulfide having an average particle size of 5 μm and graphite having an average particle size of 5 μm in a ratio of 1: 1 was used. Then, by cold rolling to 0.75 mm,
Intermediate annealing was performed in a CAL (continuous annealing furnace) at an ultimate temperature of 500 ° C., and cold rolling was performed to 0.3 mm to obtain a test material.

[0042]

[Table 5]

No. 22,23,24,28,29,3
Nos. 0 and 31 are examples of the present invention, and all showed good ironing property. On the other hand, No. In No. 25, since the area ratio of the solid lubricant was 20% or less, a slight effect was recognized in the first time, but strong galling occurred in the second time. No. 26
Similarly, since the area ratio was low, galling occurred. N
o. In No. 27, the area ratio of the solid lubricant is sufficient, but since the average particle size is too small, galling occurs. No.
In No. 32, the area ratio was small, and strong galling occurred.

[0044]

As described in detail above, according to the present invention, 3
Not limited to aluminum alloy plates produced by the 004-based aluminum alloy DC casting method, the ironing property is inferior to the metallographic structure 30
Whether it is 04 series CC material (continuous cast rolled material) or another alloy system such as 5000 series, it has good ironing workability equal to or better than 3004 series DC material, and the characteristics such as mechanical properties of the material. It is possible to obtain an excellent aluminum alloy plate for forming, which does not deteriorate.

Therefore, conventionally, since it is difficult to achieve both workability such as ironing property and strength, different alloys having different compositions have been adopted for the can lid and the can body. However, according to the present invention, the can lid and the can body are made of different alloys. For example, the same alloy such as high strength 5052 material can be adopted. As a result, there is an advantage in terms of work and cost such that only one type of alloy needs to be manufactured at the time of manufacturing, and also in terms of recycling, the conventional can lid and can body are made of different alloys, and thus are used as recycled alloys. There was no problem, or there was a problem that it was necessary to drastically adjust the alloy composition in order to use it, but since the same alloy can also be used, the recovered material can be melted as it is and used as a can material. It has a great effect.

Further, since the aluminum plate itself is pre-lubricated in advance, re-oiling or the conventional lubricating oil application work in DI processing is unnecessary, or even if lubricating oil is applied, it is extremely small. Therefore, it is possible to omit the steps.

Although this time is limited to ironing (DI) in particular, by applying the present invention to forming work such as general drawing and overhanging which is lighter than ironing, tools such as dies can be applied. Adhesion of oxides, etc. peeled off from the plate surface is reduced, maintenance man-hours such as die replacement and die screening can be reduced, workability is improved, and wear of tools such as dies due to adhered substances can be reduced. Therefore, it also has the effect of extending the tool life.

Claims (2)

[Claims] 1. A solid lubricant having an average particle size of 0.1 to 50 μm is embedded in the plate surface in an area ratio of 20% or more, and at least a part of the solid lubricant is exposed on the plate surface. A rolled aluminum alloy plate for forming that has excellent ironing workability. 2. The surface of the plate is coated with a solid lubricant having an average particle diameter of 0.1 to 50 μm, and then the plate is rolled to embed the solid lubricant in an area ratio of 20% or more. A method for producing a rolled aluminum alloy plate for forming, which has excellent ironing workability.