JPS60125346A - High strength aluminum alloy having superior workability - Google Patents

Abstract

PURPOSE:To obtain a high strength Al alloy having superior mechanical properties and formability by specifying the average grain size of an Al alloy contg. specified percentages of Mg, Zn and Cu. CONSTITUTION:An Al alloy consisting of, by weight, 6.0-10.0% Mg, 0.5-2.5% Zn, 0.05-0.30% Cu and the balance essentially Al and having >=10mum average grain size is prepd. The alloy may further contains one or more among 0.05- 0.25% Cr, 0.05-0.20% Zr, 0.05-0.50% Mn and 0.05-0.20% V. The average grain size is preferably <= about 20mum. A high strength Al alloy having >= about 35kg/mm.<2> strength and superior workability and producing no stretcher strain is obtd.

Description

[Detailed Description of the Invention] * Ia llll! Regarding the 1+ Stretch Stone T-Wh Stretched Full ζNium alloy, more specifically, it is a high-quality alloy that has excellent mechanical properties and formability, and has excellent formability without stretcher strain. Power related to aluminum alloy.

Conventionally, for example, AA was used as an aluminum alloy for automobiles.
5182 alloy is widely used, but although this alloy has excellent formability, it has low strength and is prone to stretcher strain, making it unsuitable for use in structural members and where surface quality is a problem.

In addition, 5085 alloy and 2036 alloy have been used, but although they have good strength as aluminum alloys for automobiles, they have the problem of poor formability. It was created in view of the problems with aluminum alloys used in automobiles, for example, and has a strength of 35 kg/men2.
It is an object of the present invention to provide a high-strength aluminum alloy which has the above properties, has excellent formability, and also has excellent formability without the occurrence of stretcher strain.

The high-strength aluminum alloy with excellent formability according to the present invention includes (1) Mg6. (1-10, Ou+t%, Zn
O,5-2,5wt%, CuO,05-0,30wt
%, the remainder substantially consists of A1, and the average crystal grain size is 10u or more.
6.0-10.0wt%, Zn 0.5-2.5+ll
t%, Cu O,05-0, 30 wt%, and further contains Cr 0.05-0.25 wt%, Zr O,05
-0,20+ut%, Mn 0.05-0,50wt%
, Vo, and one or more selected from 05 to 0.20 wt%, the remainder substantially consists of A1, and the average crystal grain size is 10 u or more. This invention consists of two inventions, with the second invention being an excellent high-strength aluminum alloy.

The high-strength aluminum alloy with excellent formability according to the present invention will be described in detail below.

First, the components and component ratios of the high-strength aluminum alloy with excellent formability according to the present invention will be explained.

M is an effective element for increasing strength and ductility, and if the content is less than 6.0%, sufficient strength cannot be obtained; If the content exceeds Quit%, cracks are likely to occur during hot rolling. Therefore, the Mg content is 6.
0 to 10.0 wt%.

Zn is an element that improves formability and prevents stretcher strain. If the content is less than 0.5wL%, this effect is small, and if the content exceeds 2.5@t%, the formability is reduced. . Therefore, the Zn content is 0.
5 to 2.5u+t%.

Cu is an element that increases strength, and if the content is less than 0.05 iut%, this effect will be small, and if the content exceeds 0.30 wt%, the formability will be inhibited. Therefore, the Cu content is set to 0.05-0.30WL%.

Cr, Zr, Mn, and V are elements that impart strength, and if their content is less than 0.05 wt%, this effect is small;
In addition, CrO, 25wt%, Zr and VO, 20
If the content exceeds u+t% and Mn 0050u+t%, moldability will be inhibited. Therefore, the Cr content is 0.05 to 0.
25wt%, Zr content 0.05-0.20wt%, M
n content 0.05-0.50u, t%, ■ content 0.0
5-0.20+ut%.

If the crystal grain size is less than 10 μm, stretcher strain will occur, and if the crystal grain size becomes too coarse, surface roughness will occur during molding, so it is appropriate to set it to 20 μm or less.

In addition to the above-mentioned components, Ti and Nb5B can be contained in O.1wt% or less to refine the crystal grains of the ingot, and Be can be contained in 0.05u+t% or less to prevent Mg oxidation. There is no problem with the top.

There is no problem with impurities as long as they are normally contained in industrial quantities, such as FeO, 5u+t% or less, and S10.
It is permissible if it is 3u+t% or less.

Examples of high-strength aluminum alloys with excellent formability will be described in this book, and comparative examples will also be described.

Example 1 Melting was carried out according to a conventional method so that the ingredients and proportions shown in Table 1 were obtained, and after casting, hot rolling was performed to a thickness of 3.5 mm, followed by cold rolling. It was made into a shaft plate. This was used for the test after being continuously annealed at a temperature of 500°C for 10 seconds (continuous annealing was performed at a temperature of 530 to 45
It is desirable to carry out the process at a temperature of 0° C. for 15 seconds or less.

Formability was evaluated by notch elongation, which indicates the characteristics of formability under a stress gradient.

The results are shown in Table 1, and the high-strength aluminum alloy according to the present invention with excellent formability (in Table 1, the present invention alloy)
has high strength and does not cause stretcher strain. However, stretcher strain occurs in the comparative example.

Example 2 Mg 8u+t%, Zn 1.2wt%, CuO,2
The high-strength aluminum alloy of the present invention containing u+t% and having excellent formability is continuously annealed at a temperature of 410 to 530°C, and the average grain size is changed by changing the annealing temperature. The presence or absence of strain was investigated.

The results are shown in Table 2. From this table, the average grain size is 1
It can be seen that stretcher strain does not occur when the thickness is 5μ or more.

Table 2 shows that in order to make the crystal grain size 10μ or more, 450~
It is preferable to perform short-time annealing at a high temperature of 530° C., and continuous annealing is preferable since batch type heating requires a long time and the grain size tends to become coarse.

As explained above, the high-strength aluminum alloy with excellent formability according to the present invention has the above structure, so it has high strength and excellent formability, and
It has extremely excellent effects as an automobile material that does not generate stretcher strain.

Claims (2)

[Claims] (1) Mg6.0-10. O@t%, Zn O,5
-2.5 wL%, CuO, 0.5-0.30 wt%, the remainder is substantially A1, and the average crystal grain size is 10 μ or more. Aluminum alloy. (2) Mg 6.0-10.0w1%, Zn 005
-2.5wt%, CuO,05-0,30wt%, and further contains CrO,05-0,25@t%, Zr 0.05-0
．． 20wt%, MnO, 05-0,5Qwt%, V
Containing one or more selected from O, 05-Q, 20 wt%, the remainder being substantially A1, and having an average crystal grain size of 10 μ or more. Superior high strength aluminum alloy.