JPS6013047A - High-strength aluminum alloy with superior cold workability - Google Patents

Abstract

PURPOSE:To obtain the titled alloy with superior bulging workability as well as corrosion resistance, stress corrosion cracking resistance and extrusibility by preparing a specified composition consisting of Zn, Mg, Cu, Zr, Mn, Cr, Ti, V, B and Al. CONSTITUTION:This Al alloy with superior cold workability, especially bulging workability and high strength consists of, by weight, 5.5-10.0% Zn, 1.5-2.2% Mg, 0.65-2.0% Cu and 0.05-0.25% Zr as essential components, <=0.08% Mn, <=0.1% Cr, one or more among 0.001-0.1% Ti, 0.05-0.25% V and 0.0001-0.08% B, and the balance Al with inevitable impurities. The alloy has necessary performance with respect to corrosion resistance, stress corrosion cracking resistance and extrusibility which are required when the alloy is put to practical use.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is applicable to high-strength aluminum alloys with excellent cold workability, particularly for high-strength materials that require cold working such as stretching, such as motorcycle rim materials. A
The present invention relates to a Q-Zn-Mg-Qu alloy.

Aluminum alloys, such as those used for motorcycle rim materials, have excellent strength and corrosion resistance.
Since recesses and the like for attaching spokes must be formed by stretching, it is required to have excellent cold workability. However, conventionally,
Hataρ-Zn-M, known as a high-strength aluminum alloy
The g-Cu alloy has poor cold workability even in a tempered state where it is easy to work, such as a solution state or a go-to material state, and has the disadvantage that it is easily cracked by the above-mentioned overhang processing.

After conducting various studies on the cause of this, we found that 8ρ-Zn-M
It has been found that in y-Cu alloys, Mn and Cr, which are usually added to adjust the crystal grain shape, have an adverse effect. On the other hand, as a conventional alloy, the above-mentioned Ma and cr (7) are substituted with: Zr e added A
U-Zn-Ma-CU alloys, such as A7050 alloy, are known, but these alloys still have poor cold workability such as stretch processing due to the excessive Qu content. It has been found that the quality has become inferior.

This invention is based on the above-mentioned findings, and in particular Mn and C.
By regulating the blueness of r and limiting the content of Qu to a specific range, aluminum can simultaneously satisfy both properties: high strength and excellent cold workability, especially stretch workability. The present invention aims to provide an aluminum alloy that has the required performance in terms of corrosion resistance, stress corrosion cracking resistance, extrudability, etc., which are required from the viewpoint of reliability.

For the above purpose, the high strength aluminum alloy with excellent cold workability according to the present invention contains 5.5 to 10.0% Zn.
, MOI, 5-2.2%, Cu 0.65-2.0%,
Contains Zr0.05-0°25% as an essential component, Mn 0.08% or less, Cr 0.1% or less, and other T+ o, oo1-0.1%, Vo, 05-0.25
%, at least 1 from 80.0001 to 0.08%
11 or more, with the remainder consisting of aluminum and unavoidable impurities.

In this specification, "1%" is expressed on a weight basis.

The significance of the components contained in the aluminum alloy and the proportions thereof according to the present invention will be explained as follows.

ZO is an essential element for increasing the strength of alloys as a hardening element, and if it is less than 5.5%, its effect is small;
Moreover, if the content exceeds 10.0%, corrosion cracking resistance will deteriorate. The most preferable content range of Zn is 6.0 to 8.
．． It is about 0%.

Like Zn, MQ is also an essential component for increasing strength, and if it is less than 1.5%, its effect is small; 2.
Even if it is contained in an amount exceeding 2%, it hardly contributes to improvement in strength, and on the contrary, a drawback arises in that cold workability and hot workability deteriorate.

The most preferable content range is about 1.6 to 1.8%.

Qu is an important element that is essential for improving stress cracking resistance at the same time as improving strength, but if it is less than 0.65%, its effect is small, and if it exceeds 2.0%, it will reduce cold workability. and its contribution to strength improvement is also small. The most preferred range is
It is about 0.7 to 1°5%.

2" suppresses coarse recrystallization in the alloy and changes the crystal grain shape.
& It is effective for stabilizing the structure by creating a coarse structure and improving stretchability, but if it is less than 0.05%, these effects are small, and if it exceeds 0.25%, it may cause coarse crystals. Extrusions are generated and the toughness deteriorates. The most preferable range is about 0.1 to 0.15%.

Mn is originally effective for adjusting crystal grain shape, but
On the contrary, its addition tends to deteriorate cold workability. However, if it is less than 0.08%, its harmful effects are small.

Cr, like M and n, deteriorates cold workability, but if it is less than 0.01%, the effect is small.

r+, v, and B are all effective for stabilizing the tissue, but at least one of them is
T+ o, oo1% or more, Vo, 0596JX upper, BO
,0O01%lX or more can achieve this effect. However, since too much content of these deteriorates extrudability, etc., Ti is 0.1% or less,
Vo is limited to 25% or less and 80.08% or less, respectively.

As is clear from the following Examples, the aluminum alloy according to the present invention is comparable in mechanical properties such as tensile strength, yield strength, and elongation to various conventionally known comparative alloys. In fact, it possesses superior properties and is excellent in cold workability such as stretch processing, and can be used not only as a rim material for motorcycles, etc., but also with high strength and can be used in trail processing, press processing, drawing processing, etc. Because it requires cold working such as ironing, it can be suitably used as a material for various applications that require ductility.

Note that the alloy according to the present invention can be used not only as an extruded material like the above-mentioned rim material, but also as a sheet material.

Next, examples of this invention will be shown. ,.

Examples Table 1 Extruded materials manufactured by conventional methods for aluminum alloys having various chemical compositions shown in Table 1 were solution-treated at 470°C for 1 hour, cooled with water, and then aged at 120°C for 24 hours. The sample was taken as a sample. Then, we investigated the mechanical properties and stretchability of each sample, and the results are as follows.
It was as shown in the table.

[Margins below] Table 2 In addition, in the above Table 2, the overhang workability is determined when the wall thickness is 6 m.
Take the extruded material as a sample, and directly? ! ! The height of the overhang until cracking occurred in the sample was measured when the sample was overhanged into a spherical shape using an Erichsen machine with a 17-wire punch. In addition, all evaluations were based on the use as a rim material, and were expressed as 0: good Δ: somewhat good ×: poor.

that's all patent applicant Showa Aluminum Co., Ltd.

Claims (1)

[Claims] Zn 5.5-10.0%, M91.5-2゜2%, O
LI 0.65-2.0%, Zr 0.05-0.25
% as an essential component, and Mn 080% or less and Cr 0.1% or less, and Ti 0.001~o,
i%, Vo, 05-0.25%, so, oooi-0.
1. A high-strength aluminum alloy with excellent cold workability, characterized in that it contains at least one kind of 0.08% and the remainder consists of aluminum and unavoidable impurities.