JPH036356A - Manufacture of aluminum alloy material for forming - Google Patents

Abstract

PURPOSE:To manufacture the Al alloy material for forming having excellent strength and formability by subjecting an Al alloy hot rolled material having specified compsn. constituted of Mg, Si, Mn, Cu, Fe, Cr and Al to specified soln. heat treatment, precipitating treatment and cold rolling. CONSTITUTION:An Al alloy ingot contg., by weight, 0.5 to 3.5% Mg, 0.1 to 0.6% Si, 0.05 to 1.5% Mn and 0.05 to 0.2% Cu, furthermore contg. at least one kind of 0.1 to 0.6% Fe and 0.05 to 0.3% Cr and the balance Al with inevitable impurities is subjected to homogenizing treatment of soaking to about 450 to 600 deg.C for about 48hr. Next, the ingot is hot-rolled at about 400 to 500 deg.C. The obtd. alloy material is subjected to soln. heat treatment at 450 to 580 deg.C to promote the entering of Mg and Si into solid soln. The alloy material is successively subjected to the precipitating treatment at 130 to 250 deg.C for >=0.1min. After that, the alloy material is cold-rolled at >=30% draft and, according to necessary, is furthermore, subjected to finish annealing at 100 to 250 deg.C. In this way, the Al alloy material for forming having excellent strength and formability and free from the generation of the reticulate pattern at the time of deep drawing can be obtd.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a method for manufacturing an aluminum alloy material for forming,
More specifically, the present invention relates to a method for producing a moldable aluminum alloy material that has high strength and excellent formability and is suitable for use as metal can cylinders and caps such as beverage cans and food cans.

(Prior Art) Hard and semi-hard materials such as JIS 3105 alloy, 3004 alloy, and 5052 alloy are generally used as materials for beverage cans, food can containers, PP caps, etc. manufactured by deep drawing. In order to further reduce the cost and weight of cans, cans, and caps, there is a strong desire for aluminum alloy materials that are even thinner than conventional ones, and aluminum alloys with higher strength than those conventionally used for this material are being used. material is requested.

(Problems to be Solved by the Invention) However, when attempting to increase the strength of conventional aluminum alloys by simply increasing the cold rolling rate or by increasing the content of Mg, which is the main alloying element, drawing process Not only does it cause an increase in the selvage rate and a decrease in deep drawability, but paint baking also causes a significant decrease in strength when heated (
Therefore, a problem arose in that the strength required for thinning could not be obtained.

Furthermore, as mentioned above, if the cold rolling rate and Mg content are simply increased to increase the strength of a conventional material, shear areas will occur during shrinkage flanging during cold rolling and subsequent deep drawing. A problem has arisen, which is a linear pattern that intersects at an angle of inclination of about 30 to 40 degrees with respect to the plate surface when viewed from the thickness section of the rolled plate parallel to the rolling direction during cold rolling. In particular, when Mgfx is high or when the cold rolling rate is high, the shear zone grows throughout the sheet thickness, so during rolling or subsequent press working,
It will break at that point and no further processing will be possible.

Also, during deep drawing, approximately 30
The kagome pattern, which appears as a group of curves intersecting at an inclination angle of ~40°, spoils the appearance of the container and lowers its commercial value, and if the drawing ratio is high, cracks occur along the kagome pattern. This causes a marked deterioration in deep drawing formability.

Furthermore, when drawing is performed after applying a coating film, such as on food cans or caps, there is a risk that the coating film may peel off and the corrosion resistance may deteriorate.

It is an object of the present invention to solve the above-mentioned conventional problems and provide a method for producing an aluminum alloy material for forming, which has excellent strength and formability and does not generate a kagome pattern during deep drawing.

(Means for Solving the Problems) In view of the current state of the above-mentioned prior art, the present inventors conducted intensive research and found that:
Heat treatable aluminum alloy instead of non-heat treatable aluminum alloy of 5000 series such as 000 series and ρ-Mg series,
In particular, A which causes the precipitation effect of Mg-Si intermetallic compounds by aging treatment or baking treatment.
By using the °C-Mg-5i series alloy, sufficient strength and good formability can be obtained as an aluminum alloy plate for cans or caps. In the case of , solid solution Mg atoms in the alloy and mobile dislocations introduced by cold rolling etc. are caused by dynamic strain aging, and this occurs during cold rolling or subsequent press working in the thickness direction. (1) Even in 60006000 series heat-treatable alloys, the fine precipitated phases that are consistent or semi-coherent with the matrix that occur in the early stages of aging are intersected by mobile dislocations introduced by cold rolling, etc. However, by performing precipitation treatment before cold rolling to coarsen the precipitates to some extent, the formation of shear zones can be prevented and the formability of the final sheet can be improved. ,
Based on this knowledge, the present invention was accomplished.

That is, the present invention includes (1) Mg 0.5 to 35% by weight (hereinafter, % in the metal composition indicates weight%), Si 0.1
~0.6%, Mn 0.05-1.5% and Cu0.0
Contains 5-0.2% and further Fe 0.1-0.6%
An alloy obtained by homogenizing and hot rolling an aluminum alloy ingot containing at least one selected from 0.05 to 03% of Cr, with the balance being AI2 and unavoidable impurities. After applying solution treatment to the plate at a temperature of 450 to 580℃, followed by precipitation treatment at a temperature of 130 to 250℃ for 0.1 minutes or more, the reduction rate is 30%.
(2) A method for producing an aluminum alloy material for forming (referred to as the first invention), characterized in that the cold rolling is performed as described above, The present invention provides a method for producing an aluminum alloy material for forming according to the present invention (referred to as the second invention).

Regarding the aluminum alloy material according to the present invention, the effects of each component and the reason for limiting the content will be described below.

Mg is set to 0.5 to 3.5%. Mg dissolves in solid solution in the matrix and has the effect of increasing the strength of the blank plate and precipitating Mg-5i compounds to strengthen it.

If the Mg content is less than 0.5%, it is quantitatively insufficient to precipitate and strengthen Mg-3i compounds, and 3.5
%, toughness deteriorates and formability is impaired.

Si is set to 0.1 to 0.6%. Along with Mg, Sl is Mg-
It has the effect of precipitating and strengthening 3i-based compounds. Si
If the content of Aj2-Mg-3i is less than 0.1%, it is insufficient in quantity to precipitate and strengthen Aj2-Mg-3i-based compounds by aging treatment or baking, and if the content exceeds 0.6%, , has high quenching sensitivity (so coarse Mg5L alloys precipitate at grain boundaries during the cooling process after solution treatment, deteriorating toughness and reducing formability. Furthermore, A
The amount of precipitated C-Mg-Si compound is insufficient and sufficient strength cannot be obtained.

Mn is set to 0.05 to 1.5%. Mn has the effect of refining crystal grains to improve formability and strength. If the content is less than 0.05%, the above effects will be small (
On the other hand, if it exceeds 1.5%, coarse intermetallic compounds are formed and drawability deteriorates.

Cu is set to 0.05 to 0.2%. Cu has the effect of forming fine precipitates during baking and improving strength. If the content is less than 0.05%, the above effects will be diminished, and if it exceeds 0.2%, the crystal grains will become coarse, roughening will occur during deep drawing, and corrosion resistance will deteriorate.

Fen, 1-0.6%, Cr 0.05-0.3%,
At least one or more selected from these is contained within the above range. Fe and Cr refine the crystal grains, improve formability, stabilize the texture, and reduce the cup-edge ratio.
Furthermore, it has the effect of improving strength. Each content is 0
．． If the content is less than 1% or 0.05%, the above effects will be small (on the contrary, if the content exceeds 0.6% or 0.3%, respectively, coarse intermetallic compounds will be formed and the drawability will deteriorate.

In addition, Ti, which is usually added as a refining agent for the ingot structure,
B is preferably added in an amount of 0.1% or less and 0.02% or less, respectively.

There is no particular problem as long as other impurities are 0.1% or less.

Next, the method for manufacturing the alloy material of the present invention will be described. First, a molten aluminum alloy containing the above-mentioned components is cast according to a conventional method. Semi-continuous casting is generally used as this casting method, but continuous thin plate casting may also be used to save energy and improve mechanical properties. The obtained ingot was subjected to soaking treatment (
homogenization process). This soaking treatment condition is such that the soaking temperature is set at 450-660℃ in order to refine the crystal grains of the solution treatment.
It is preferable that the temperature and soaking time be 48 hours or less.

After the soaking treatment, hot rolling is carried out, but there is no need to strictly control this hot rolling (400 mm according to the usual method).
Hot rolling may be performed at ~500''C.

Next, solution treatment is performed, but cold rolling may be performed before that. By performing cold rolling, the crystal grains in the solution treatment can be further refined.

Solution treatment promotes solid solution of Mg and Si into the alloy,
The heating temperature is in the range of 450 to 580°C. That is, if the solution temperature is less than 450°C, solid solution of Mg and Si will not be sufficiently achieved, and if it exceeds 580°C, local dissolution of Mg will occur due to burning, which is not preferable. The solution annealing method can be a normal batch annealing followed by rapid cooling, or a continuous annealing method with rapid heating and rapid cooling, but the continuous annealing method can control the selvage ratio, improve formability by refining grains, and improve productivity. It is desirable from the point of view.

In addition, the cooling temperature is set at 5'C/sec to prevent the formation of precipitates during the cooling process after solution heating and to ensure the strength of the final plate.
It is desirable to set the above.

Next, a precipitation treatment is performed, and this precipitation treatment is carried out at a temperature of 130 to 250
The purpose of heating at ℃ is to improve the strength of the final plate through precipitation hardening, as well as to coarsen the precipitated phase and suppress the occurrence and growth of cracks during cold rolling and subsequent press working. If the treatment temperature is less than 130°C, a large number of fine precipitated phases will be formed, and although the strength will be improved, it is undesirable because it will make it easier to form a new grain, and if the temperature exceeds 250°C, a new grain will not be formed. This is not preferable because the strength decreases. Also, the aging retention time is 0. The reason why the holding time is set to 1 minute or more is because the above effects are insufficient if the holding time is less than 0.1 minute.

Next, cold rolling is performed, and the cold rolling is performed at a reduction rate of 30% or more in order to improve the strength of the blank plate through work hardening, while a reduction rate of less than 30% corresponds to thinning of the blank plate. This is not preferable because sufficient strength cannot be obtained.

Next, in the second invention, finish annealing is performed after cold rolling. This is to recover the processed structure and improve formability (drawing, stretchability). If the annealing temperature is less than 100°C, the desired formability cannot be secured; on the other hand, at 250°C
If it exceeds this, recovery progresses too much and sufficient strength cannot be obtained, which is not preferable.

The alloy material of the present invention obtained in this way is subjected to degreasing and other treatments and then painted and baked for several minutes at a temperature of about 200°C before drawing, or even if painted and baked, it has no strength. The aluminum alloy material is suitable as an aluminum alloy material for forming cans, caps, etc. because the decrease in strength is small or the strength is improved compared to before baking.

(Example) Next, the present invention will be explained in more detail based on examples.

Melting A2 alloy with the composition shown in Table 1 by a normal method,
After forming the ingot and facing it, it was homogenized and hot-rolled into a plate with a thickness of 3 mm. Next, this hot-rolled plate was subjected to cold rolling to form a plate with a thickness of 0.4 to 1.5 mm, and then subjected to solution treatment, precipitation treatment, final cold rolling and the like under the conditions shown in Table 1. Inventive methods 1 to 3 and comparative methods 4 to 14 were carried out by performing final annealing, respectively, to produce AQ alloy plates 1 to 3 by the inventive method and comparative A12 alloy plates 4 to 14 by the comparative method. These Aj
2 alloy plate (final plate thickness 0.25 mm) was baked at 200°C for 10 minutes, and then a drawn cup was produced by deep drawing using a die with a diameter of 33 mm and a shoulder radius of curvature of 4.5 mm. Then, the critical drawing ratio (L, D, R,) was measured, and the presence or absence of a zigzag pattern on the side wall of the cup was also measured. Further, the tensile strength was measured by a 0.2% proof stress test of the board before and after baking. These results are shown in Table 2.

2 Table 2 *200°C x 10 minutes** Kagome pattern judgment O: Good (no Kagome pattern generated) All of the A42 alloy plates 1 to 3 of the present invention that were tested were conventional J I 55052 (No, 15), JIS 30
04 (No. 16) and JIS3105 (No. 17)
) Compared to alloy plates, it has high strength and excellent formability, and no kagome pattern is observed.

In addition, comparative Aρ manufactured by the comparative method (No. 4 to 14)
Alloy plates No. 4 to 14 are inferior in at least one of these properties.

That is, the alloy plate with Mg content below the lower limit (No. 4)
The alloy plate (No. 8) with a Cu content below the lower limit has good formability but lacks strength. In addition, the alloy plate (No. 5) in which the Mg content is above the upper limit and the alloy plate (No. 7) in which the Si content is added in excess of the upper limit, both suffer from a large decrease in strength due to baking heating and lack strength. In addition, the alloy plate (No. 8) in which the Mn content exceeds the upper limit has deteriorated formability. Furthermore, the alloy plate (No. 10) whose solution temperature is less than the lower limit is likely to have a kagome pattern if its strength is insufficient, and the alloy plate (No. 11) whose cold rolling rate is less than the lower limit is , strength is insufficient.

Furthermore, alloy plate No. 12.13, in which the precipitation treatment temperature or time was less than the lower limit, had sufficient strength but had frequent kagome patterns and poor formability. In addition, the alloy plate (No. 14) whose precipitation treatment time exceeds the upper limit has insufficient strength and poor formability.

(Effects of the invention) As described above, the method of the present invention has excellent strength and moldability,
In addition, an aluminum alloy material for forming that does not generate a kagome pattern during deep drawing can be obtained, and this alloy material can be suitably used for packaging containers such as cans and caps.

Claims (2)

[Claims] (1) Mg0.5-3.5%, Si0.1-0.6%,
Contains Mn0.05-1.5% and Cu0.05-0.2%, further Fe0.1-0.6%, Cr0.05-0.05%
An aluminum alloy ingot containing at least one selected from 0.3% (wherein, % indicates weight %) and the remainder Al and unavoidable impurities is subjected to homogenization treatment and hot rolling. 450 to 58 to the alloy material obtained by applying
Solution treatment was performed at a temperature of 0°C, followed by 130~25
A method for producing an aluminum alloy material for forming, which comprises performing a precipitation treatment at a temperature of 0° C. for 0.1 minutes or more, followed by cold rolling at a reduction rate of 30% or more. (2) The method for producing an aluminum alloy material for forming according to claim (1), wherein after the cold rolling, final annealing is performed at a temperature of 100 to 250°C.