JPH1017972A - Aluminum alloy for casting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an aluminum alloy for casting, improved in toughness without causing deterioration of tensile strength and proof stress. SOLUTION: In the composition of this aluminum alloy, the contents of Fe and Si as impurities are regulated, by weight, to 0.0005-0.01% and 0.0005-0.01%, respectively, and 0.2-5.0% Mg, 0.5-8.0% Zn, 0.05-1.0% Cu, 0.10-0.50% Ti, 0.002-0.01% B, and 0.05-0.60% of one or >=2 elements among Mn, Cr, and Zr are incorporated and, if necessary, Be is added by 0.001-0.005%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an aluminum alloy for castings.

[0002]

2. Description of the Related Art In recent years, Al-Zn-Mg
-Cu-based aluminum alloy castings have begun to be used. A
The l-Zn-Mg-Cu-based aluminum alloy has the advantage that the strength can be improved by natural aging, but has the problem that the toughness (elongation) decreases with the improvement in strength.

[0003]

As described above, Al-Zn-Mg-Cu-based aluminum alloy castings have begun to be used, but have many problems. An object of the present invention is to provide an aluminum alloy for castings having improved toughness without reducing tensile strength and proof stress.

[0004]

In order to achieve the above object, the present invention provides an aluminum alloy having the following composition. That is, Fe as an impurity is 0.0005 to
0.01wt%, 0.0005-0.01wt% Si
And Mg 0.2 to 5.0 wt%, Zn 0.5 to
8.0 wt%, Cu 0.05-1.0 wt%, Ti0.
10-0.50wt%, B0.002-0.01wt
%, Mn, Cr, Zr, or two or more of them in an amount of 0.05 to 0.06 wt%.
It is an aluminum alloy for casting to which 01 to 0.005 wt% is added.

The reasons for limiting the composition of each component of the aluminum alloy according to the present invention will be described below. Fe forms Al-Fe-Si and Al-Cu-Fe compounds at the time of casting and solidification, and reduces the toughness to 0.01% by weight or less. However, even if less than 0.0005% by weight, the effect is improved. Therefore, the content is set to 0.0005 to 0.01 wt%.

[0006] Si also forms an Al-Fe-Si compound in the same manner as Fe and reduces the toughness to 0.01% by weight or less. However, even if it is less than 0.0005% by weight, its effect is not improved. 0005 to 0.01 wt%.

[0007] Zn is 0.5% to improve tensile strength and proof stress.
However, if it exceeds 8.0 wt%, the stress corrosion cracking resistance and the casting crack resistance are reduced.
〜8.0 wt% is optimal.

[0008] Mg is 0.2 wt% to improve the tensile strength
The addition is made as described above, but if it exceeds 5.0 wt%, the toughness and the feedability deteriorate, so 0.2 to 5.0 wt% is optimal.

Cu is used in an amount of 0.0 to improve tensile strength and proof stress.
5 wt% or more is added, but if it exceeds 1.0 wt%, the toughness decreases, so 0.05 to 1.0 wt% is optimal.

Mn, Cr and Zr are added in an amount of 0.05 wt% or more to prevent a decrease in toughness in order to improve tensile strength and proof stress and to prevent stress corrosion cracking. Properties and toughness are reduced.
5 to 0.60 wt% is desirable.

[0011] Ti is added in an amount of 0.10 wt% or more for refining the cast structure and improving mechanical properties.
If the content exceeds wt%, a coarse Ti compound is generated and the toughness is reduced, so the content is set to 0.10 to 0.35 wt%.

B combines with Ti to refine the casting structure,
0.002wt% or more is added to improve castability.
Even if the content exceeds 0.01 wt%, no improvement in the effect is observed, so that 0.002 to 0.01 wt% is optimal.

Be is 0.001 to prevent Mg oxidation.
wt% or more, but if the content exceeds 0.005 wt%, no improvement in the effect is observed, so 0.001 to 0.005 w
A range of t% is desirable.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to examples and comparative examples. Various aluminum alloys shown in Table 1 were melted and cast in air in molds.
(2) The hardness was measured. The test conditions are shown below. (1) Tensile test device Instron type tensile tester Test piece JIS No. 4 test piece (2) Hardness test device Brinell hardness tester

[0015]

[Table 1]

Example Table 2 shows the results of a tensile test and a hardness measurement of a test piece cast into a mold and cut out.

[0017]

[Table 2]

The alloy of the present invention has the same tensile strength as the comparative material,
The proof stress and the hardness were shown, and the elongation was improved by about 10%.

As is clear from the examples, the reason why the alloy of the present invention shows performance equal to or higher than that of the comparative material is that the impurities Fe,
It is considered that the content of Si and Si was limited to 0.0005 to 0.01 wt%.

[0020]

According to the present invention, the content of Fe and the content of Si are limited to 0.0005 to 0.01 wt%, and Zn,
Add appropriate amount of Mg, Cu, Mn, Cr, Ti, B, Be
If the adjusted alloy is cast by various casting methods (all casting processes such as sand mold, mold, lost wax, shell mold, etc.), it shows tensile strength, proof stress, hardness comparable to that of comparative material and improvement of elongation. It is an alloy that is optimal for products that require toughness because of its strength.

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[Procedure amendment]

[Submission date] September 13, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 1

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction contents]

[0004]

In order to achieve the above object, the present invention provides an aluminum alloy having the following composition. That is, Fe as an impurity is 0.0005 to
0.01wt%, 0.0005-0.01wt% Si
And Mg 0.2 to 5.0 wt%, Zn 0.5 to
8.0 wt%, Cu 0.05-1.0 wt%, Ti0.
10-0.50wt%, B0.002-0.01wt
%, Mn, cr, Zr, or two or more
0.05-0.60 wt% , in some cases Be0.0
It is an aluminum alloy for casting to which 01 to 0.005 wt% is added.

Claims (1)

[Claims] 1. The method according to claim 1, wherein 0.0005-Fe is used as an impurity.
0.01wt%, 0.0005-0.01wt% Si
And Mg 0.2 to 5.0 wt%, Zn 0.5 to
8.0 wt%, Cu 0.05-1.0 wt%, Ti0.
10-0.50wt%, B0.002-0.01wt
%, Mn, Cr, Zr, or two or more of them in an amount of 0.05 to 0.06 wt%.
Aluminum alloy for casting to which 01 to 0.005 wt% is added.