JPH06108194A - Rigid moldable isotropic aluminum alloy for stretching and drawing - Google Patents

Abstract

PURPOSE: To produce a lighter can subjected to strong drawing in accordance with a production program equal to that for the conventional alloys in such a manner that the material is economized.

CONSTITUTION: An Al base alloy for spinning and/or drawing having the following compsn. is provided: the alloy compsn. contg., by weight, ≤0.25% Fe, ≤0.25% Si, 0.8 to 1.6% Mn, 0.7 to 2.5% Mg, 0.20 to 0.6% Cu, 0 to 0.35% Cr, 0 to 0.1% Ti, 0 to 0.1% V and the other elements by ≤0.05% respectively and ≤0.15% in total, or contg. 0.7 to 1.5% Fe, ≤0.4% Si, ≤0.8% Mn, 1.5 to 3% Mg, 0 to 0.6% Cu, 0 to 0.35% Cr, 0 to 0.1% Ti, 0 to 0.1% V and the other elements by ≤0.05% respectively and ≤0.15% in total, and the balance Al.

COPYRIGHT: (C)1994,JPO

Description

Detailed Description of the Invention

The present invention relates to aluminum-based alloys for drawing and / or drawing which have high mechanical strength, good isotropic properties (low ear index) and good cold formability.

It is known that the 3004 or 3104 alloy according to the Aluminum Association name is commonly used in the production of can bodies by drawing.

Current developments are mechanically stronger, which may reduce the wall thickness for a given application, and are more isotropic,
In other words, alloys have been sought which have a low selvage index in the case of drawing and / or drawing in order to improve their usefulness, while at the same time retaining sufficient cold formability. This is because the above-mentioned conventional alloy is relatively difficult to combine the first and last two properties.

US-A-4318755 describes alloys of this type, but their cold-worked mechanical properties are relatively normal, R: 280-300 MPa,
E0.2: 250 to 280 MPa and elongation: 2 to 4%
That is, an acceptable degree of formability by drawing and drawing is guaranteed while maintaining good isotropy.

The aluminum-based alloys of the present invention having a high degree of mechanical properties, good isotropy and good formability belong to two distinct classes, (I) being derived from the conventional 3004 alloy. And (II) is essentially Fe and Mg
Containing additives.

The alloy of the present invention is distinguished from the prior art by two basic analytical features: low Fe content but conventional Mn content and low Mn content but high Fe. . Moreover, the Cu content is preferably relatively high.

More precisely, the alloy according to the invention has the following composition in% by weight: (I) (II) Fe ≤0.25 0.7-1.5 Si ≤0.25 ≤0.4 Mn 0. 8 to 1.6 ≤0.8 Mg 0.7 to 2.5 1.5 to 3 Cu 0 to 0.6 0 to 0.6 Cr 0 to 0.35 0 to 0.35 Ti 0 to 0.1 0-0.1 V 0-0.1 0-0.1 Inevitable impurities respectively ≤0.05% by weight ≤0.05 Total ≤0.15% by weight ≤0.15 Al balance balance balance In composition (I), 0.20% by weight or more, further 0.2
A Cu content of 5% by weight or more is preferred. Similarly, 0.20
Fe contents of up to and including 0.1% by weight are preferred.

Furthermore, the crude precipitates of the primary compounds are harmful during the subsequent rolling and / or drawing and drawing operations,
It has been found to be preferable to limit the content of Mn, Fe and Mg in order to avoid these coarse precipitates, as they induce defects. In this case, the following relationships are observed:% Mn + 0.9% Fe + 0.3% Mg ≦ 1.9.

Similarly, while maintaining a high degree of isotropy, without intermediate annealing (first thickness-final thickness) / cold deformation defined by the first thickness is higher than 50%. Or, in order to be higher than 60% or 65%, the following relationship must be taken into account with respect to composition (I):% Mn-2.25% Fe ≧ 0.50.

The limit of each content is determined for the following reasons.

Fe ≧ 0.25 and / or Si ≧ 0.25
In the composition (I), the micrograph structure after homogenization or heating and hot rolling has a "white band".
s) ”appears and the Mn content is low in these zones,
Therefore, the anisotropy of the material is promoted.

The lower limits of the contents of Mn and Mg are determined in order to obtain sufficient mechanical strength. On the other hand, when Mn exceeds 1.6% by weight, primary intermetallic particles, which are harmful to formability during rolling or drawing and / or drawing, appear.
With Mg ≧ 2.5 wt%, defects such as sticking on the die (also called the ring) and excessively high anisotropy appear during the drawing process.

The Cu content is based on the canned food manufacturing standard (1987).
It is kept below 0.6% by weight in order to meet the regulations of August 27), but higher than 0.20% by weight and even less than 0.2% in order to obtain the desired high mechanical properties by baking the coating.
It is preferably higher than 25% by weight.

If the Cr content exceeds 0.35% by weight, coarse primary intermetallic compounds appearing which are harmful to formability due to damage. The upper limits of the Ti and V contents are determined for the same reason.

The preferred composition is 1.2-1.6% by weight.
Mn, 0.8-1.2 wt% Mg, 0.2-0.6
Contains wt% Cu and up to 0.25 wt% Cr.

With respect to composition (II), the Mn content is preferably kept below 0.40% by weight, more preferably below 0.35% by weight. Similarly, the Fe content is preferably 1.0
5% by weight or more, more preferably 1.10% by weight or more. These two measures can preferably also be combined.

The limit of each content in the composition (II) is determined for the following reason.

When the Fe content is less than 0.7% by weight, an increase in the problem of anisotropy (large ears of 45 °) and a defect of adhesion during drawing are observed. If it exceeds 1.5% by weight, rough primary phase and damage appear due to rolling and drawing and / or drawing operations.

When the Mn content exceeds 0.8% by weight, coarse grains appear which are harmful to rolling and / or drawing and drawing due to damage.

If the Mg content is less than 1.5% by weight, the mechanical properties are insufficient. If it is more than 3% by weight, the anisotropy is too large and adhesion-type defects are recognized during the drawing process.

The Cu content is kept below 0.6% by weight to meet the food canning manufacturing standards.

When the Cr content exceeds 0.35% by weight, primary precipitates harmful to formability (damage) appear. The upper limits of the Ti and V contents are determined for the same reason.

The preferred composition is 1.1 to 1.4 wt% Fe, 1.6 to 2.5 wt% Mg and 0.25 wt%.
Up to Cr.

Uses of the alloys of the invention 3004 and 3104
Similar to alloy, but as detailed in the examples, except as to the need for intermediate annealing of alloy (I).

The manufacturing program therefore basically consists of the following operations, which result in a blank suitable for drawing and drawing operations: -casting, generally by semi-continuous ingot casting or direct strip casting; -homogenization Or heating; -hot rolling to an intermediate thickness; -cold rolling, optionally with intermediate annealing.

The cold deformation degree is 50 even without intermediate annealing.
It should be noted that the product retains good isotropy if more than 60% or even 60% or 65%.

The basic difference between the conventional 3004 alloy and the alloy of the invention (I) lies in the limited Fe and / or Si content, which results in hot-rolled products (generally sheets having a thickness of more than 3 mm or The strips) have a very different micrograph texture.

The conventional 3004 alloy contains coarse primary intermetallic precipitates and intragranular secondary precipitates present in the interdendritic zone as well as a fine "white band" with no precipitate in the interdendritic zone.
Is characterized by the presence of an organization that includes In contrast, the alloys of the invention have a similar microstructure but no "white bands".

The alloy according to the invention is therefore characterized by a very uniform distribution of the primary and secondary precipitates in the Al-based matrix from the ingot stage.

FIGS. 1, 2 and 3 are 40 of the conventional 3004 alloy (Example 0) and the alloys obtained in Examples 1 (or 3) and 2 of the present invention respectively in a hot-rolled rough state.
It is a micrograph of 0 times magnification.

FIG. 4 shows the distance (μm) calculated from the interdendritic zone of the dendrite cross section of the conventional 3004 alloy (thick line) and the alloy of the present invention (thin line) having a width of about 95 μm.
3 is a graph showing the distribution (volume%) of precipitates as a function of

[0032]

[Examples] 3 adopted as a standard according to the following examples
The present invention will be further described in comparison with 004 alloy.

In these examples, the properties of the materials obtained were determined by the mechanical properties of traction (transverse direction), the horn index X45 / 90 defined below, and the LDR defined below.
And LIR values.

Horn content:

[0035]

[Equation 1]

Here,

[0037]

[Equation 2]

Where H is the height of the cylindrical formed workpiece in the direction forming an angle α with the rolling direction, and H is

[0039]

[Equation 3]

The average value of the heights of the cylinder-formed workpiece defined by (n is the number of extreme values = 2 × the number of ears).
See NFA Standard 50-301, June 1976.

LDR (limiting drawin)
g ratio) is a predetermined drawing condition, that is, lubrication, blank holding pressure, punch shape (round shape), ratio of no fracture appearing under the thickness of sheet (blank), maximum blank φ / punch φ. .

LIR (limiting ironin)
g ratio (%) enables drawing on a cylindrical punch without defects appearing under certain conditions such as tool shape (die / punch), lubrication, initial thickness, number of passes (generally 3) The ratio: LIR = 100 (e _o −e _f ) / e _{o is} the nominal value, where e _o is the initial wall thickness and e _f is the final thickness.

The following examples (1-5) illustrate the invention with reference to alloy 3004 (example 0). Examples 1-3 are compositions (I), Examples 4 and 5
Relates to composition (II).

An alloy having the chemical composition shown in Table 1 was prepared as 110
It was cast into a plate of 0 × 300 × 2650 mm ³ , homogenized or heated, peeled, hot-rolled to a thickness of 3 mm, optionally subjected to intermediate annealing, and cold-rolled to a thickness of 0.3 mm.
Details of the conditions are shown in Table 2 (state H1x).

20 simulations of varnish baking
It was carried out by holding at 4 ° C for 10 minutes (state H2
8).

The results obtained are shown in Table 3.

The following were found: Example 1 exhibits a high degree of mechanical properties and low anisotropy,
It has moldability comparable to 3004.

Example 2 shows good formability and a very high degree of mechanical properties, the isotropy being much greater than 3004.

-Example 3 exhibits a particularly high isotropy, and the mechanical strength and moldability characteristics are the same as 3004.

Examples 4 and 5 show particularly high mechanical properties, with isotropic and formability properties at least equal to 3004.

The present invention is mainly used in the production of pultruded cans, especially beverage cans, which allows lighter and / or stronger cans to be used in a conventional alloy (3004 ...
3104), the production program can be simplified by using a production program that is completely similar to that of 3104) and avoiding intermediate annealing.

[0052]

[Table 1]

[0053]

[Table 2]

[0054]

[Table 3]

[Brief description of drawings]

FIG. 1 is a micrograph showing a metal structure of a conventional 3004 alloy (Example 0).

FIG. 2 is a micrograph showing a metal structure of an alloy of the present invention (Example 1 or 3).

FIG. 3 is a micrograph showing the metal structure of an alloy of the present invention (Example 2).

FIG. 4 is a graph showing the distribution of precipitates in a conventional 3004 alloy and the alloy of the present invention.

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[Submission date] December 3, 1992

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Claims (17)

[Claims] 1. Fe ≦ 0.25% by weight, Si ≦ 0.25
% By weight, Mn 0.8-1.6% by weight, Mg 0.7-2.
5% by weight, Cu 0.20 to 0.6% by weight, Cr 0 to 0.
35% by weight, Ti 0 to 0.1% by weight, V 0 to 0.1% by weight, other elements <0.05% by weight, total <0.1%
An Al-based alloy for drawing and / or drawing, which contains 5% by weight and the balance is Al. 2. Alloy according to claim 1, characterized in that the Fe content is less than 0.20% by weight. 3. Alloy according to claim 1, characterized in that the Fe content is less than 0.15% by weight. 4. The alloy according to claim 1, wherein the Cu content is higher than 0.25% by weight. 5.% Mn + 0.9% Fe + 0.3% Mg ≦
Alloy according to one of the claims 1 to 4, characterized in that it is 1.9. 6. Mn 1.2 to 1.6% by weight, Mg 0.8
~ 1.2 wt%, Cu 0.2-0.6 wt% and Cr
Alloy according to one of the claims 1 to 5, characterized in that it contains 0.25% by weight or less. 7. Alloy according to claim 1, characterized in that% Mn−2.25% Fe ≧ 0.50. 8. In a homogenized state or a hot rolled state,
Alloy according to one of the claims 1 to 7, characterized in that its structure consists of an Al-based matrix containing uniformly distributed primary and secondary precipitates, with no white bands. 9. Fe ≦ 0.25% by weight, Si ≦ 0.25
% By weight, Mn 0.8-1.6% by weight, Mg 0.7-2.
5% by weight, Cu 0 to 0.6% by weight, Cr 0 to 0.35% by weight, Ti 0 to 0.1% by weight, V 0 to 0.1% by weight, other elements <0.05% by weight, total <0% Al consisting of casting, homogenizing or heating, hot rolling, cold rolling without intermediate annealing, containing 15% by weight, balance Al
A method for obtaining a rolled strip of alloy, characterized in that% Mn-2.25% Fe ≧ 0.50 and the cold deformation degree is higher than 50%. 10. Fe 0.7 to 1.5 wt%, Si ≦
0.4 wt%, Mn ≦ 0.8 wt%, Mg1.5-3 wt%, Cu0-0.6 wt%, Cr0-0.35 wt%, Ti0-0.1 wt%, V0-0. 1% by weight, other elements <0.05% by weight, total <0.15% by weight
An Al-based alloy for drawing and / or drawing, which contains Al and the rest is Al. 11. Obtained by a conventional semi-continuous casting or continuous strip casting method, characterized in that the following formula is obtained:% Mn + 0.9% Fe + 0.3% Mg ≦ 1.9.
The alloy according to 0. 12. Alloy according to claim 10, characterized in that Mn ≦ 0.40% by weight. 13. The alloy according to claim 12, characterized in that Mn ≦ 0.35% by weight. 14. The alloy according to claim 10, wherein Fe ≧ 1.05% by weight. 15. Alloy according to claim 14, characterized in that Fe ≧ 1.10% by weight. 16. Fe1.1 to 1.4% by weight, Mg1.
Alloy according to one of claims 9 to 15, characterized in that it contains 6-2.5% by weight and not more than 0.25% by weight Cr. 17. Fe 0.7 to 1.5% by weight, Si0.
4 wt% or less, Mg 1.5 to 3 wt%, Cu 0.6 wt% or less, Cr 0.35 wt% or less, Ti 0.1 wt% or less, V 0.1 wt% or less, impurities each 0.05 wt% or less, Al alloys containing less than 0.15% by weight in total, consisting of casting, homogenizing or heating, hot rolling, cold rolling without intermediate annealing, characterized in that the cold deformation is higher than 50%. Method of obtaining a rolled strip of alloy.