JPH03173736A - High strength aluminum alloy capable of hollow extruding by combination die - Google Patents

Abstract

PURPOSE:To manufacture the high strength Al alloy capable of extruding a thin hollow shape material by a combination die by incorporating specified ratios of Mg, Zn, Cu and Zr into Al. CONSTITUTION:An Al alloy contg., by weight, 1.3 to 2.0% Mg, 5.0 to 8.0% Zn, 0.4% to 1.0% Cu, 0.1 to 0.2% Zr and the balance Al with inevitable impurities is manufactured by the conventional method. In this way, the high strength Al alloy capable of subjecting a thin shape material to hollow extruding by an combination die such as a porthole die can be obtd., and the obtd. hollow extruded material is provided with about >=50kg.fmm<2> tensile strength.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to hollow extruded sections by a combination die such as a boathole die, for example, a combination die used for hollow extrusion sections for motorcycle frames, rear hawks, and other structures. This invention relates to a high-strength aluminum alloy that can be hollow extruded.

Conventional technology When producing a hollow extruded section as described above using a combination die such as a boathole die consisting of a combination of a male die and a female die, the material used is conventionally 7N0.
1.7003 alloy was used.

Incidentally, in recent years, with the demand for weight reduction of devices such as vehicles, there has been a demand for reducing the weight of hollow extruded shapes used as parts and the like by making the walls thinner. Since the strength of the hollow shape material decreases when the shape is made thinner, it is essential to improve the strength of the hollow shape material itself.For this purpose, 50 K9 f/
- Tensile strength of at least a certain degree is now required.

Problems to be Solved by the Invention However, the conventional material 7N01.7003 alloy has poor strength as a material itself, and cannot satisfy the above requirements.

On the other hand, 7075 alloy exists as a material that satisfies the required strength, but boathole extrusion is not possible with this alloy.

Moreover, since it is highly sensitive to quenching, it is necessary to carry out a compacting treatment after extrusion, and as a result, quenching distortion occurs, making it difficult to manufacture complex hollow shapes such as those obtained by boathole extrusion.

The present invention was made in view of the above technical background, and it is possible to manufacture hollow shapes using a combination die such as a boat hole die, and a 50Kyf/#II
The purpose of the present invention is to provide an aluminum alloy having a tensile strength of approximately J or more.

Means for Solving the Problems The above objectives are as follows: Mg: 1. 3-2. 0wt%, Z
n: 5. O~8. 0wt%, Cu: 0.4~
Contains 1°0 wt%, Zr: 0.1 to 0.2 wt%,
This is achieved by a high-strength aluminum alloy that can be hollow extruded using a combination die, characterized in that the balance consists of aluminum and unavoidable impurities.

First, in the alloy composition of the present invention, Mg contributes to improving the strength of the extruded material. However, if it is less than 1.3 wt%, the effect is poor. On the other hand, if it exceeds 2.0 wt%, extrudability will be inhibited, causing problems in hollow extrusion using a combination die such as boathole extrusion. A particularly preferable range of Mg is 18
It is 4-1°7vt%.

Zn is also effective in improving the strength of extruded materials. However, 5. If it is less than 0wt5, the effect is poor. On the other hand 8
．． If it exceeds 0wt%, stress corrosion cracking resistance (SCC resistance)
(sexuality) worsens. A particularly preferable range of Zn is 5.5 to 7
．． It is 5vt%.

Cu has the effect of improving the stress corrosion cracking resistance of the crimped part of the extruded material. However, if it is less than 0.4 wt%, the effect is small, and if it exceeds 1.0 wt%, hardenability and extrudability deteriorate, making boathole extrusion difficult. A particularly preferred range of Cu is 0.5 to 0.7 vt%.

2" contributes to the refinement of the structure.

However, if O is less than 1 wt%, the effect is poor;
．． Even if it exceeds 2 wt%, the effect will not be increased significantly, and on the contrary, it will cause economic waste. A particularly preferable range of Zr is 0.
It is 12-0.17vt%.

Hollow extrusion using a combination die such as boathole extrusion using the aluminum alloy according to the present invention may be carried out according to a conventional method. For example, a cast billet is soaked and then hot extruded. Immediately after extrusion, the product is cooled and quenched using a fan or water spray, or separately subjected to compaction treatment and quenching treatment, followed by aging treatment to obtain the desired hollow extruded material.

Effects of the Invention The aluminum alloy according to the present invention can be hollow extruded using a combination die such as a boathole die due to the combination of each element and composition range, and the obtained hollow extrusion material has a heat resistance of 50 K'J f. A tensile strength of /- or more can be imparted. Therefore, not only is it possible to manufacture a hollow section with a complicated shape, but its high strength also makes it possible to make the section thinner, which contributes to the reduction in size and weight of devices such as vehicles. Moreover, since the 7075 alloy is not very sensitive to hardening, it can be hardened easily and the subsequent aging treatment can be carried out satisfactorily.

Example Next, examples of this invention will be shown.

D
After casting into a billet with a diameter of 178 IIM by C casting, it was soaked at 470° C. for 8 hours.

Next, using a bridge die which is a combination die, the above billet was diced at a billet temperature of 480°C and a ram speed of 0.1 m.
/ ■ At a speed of 1n, length 40 shoes, width 100 mgg, wall thickness 3
First, the feasibility of extrusion was investigated by extruding it into M hollow square material. As a result, sample N.

Extrusion could be carried out without any problems except for the 7075 alloy in No. 6. In contrast, 7075 alloy was difficult to extrude.

Next, each of the hollow extruded materials described above was quenched by cooling with a fan and water spray immediately after extrusion. After extruding and leaving for 24 hours, 70℃ x 5 hours + 140℃
Aging treatment was performed for 10 hours.

The tensile strength of each hollow extruded shape obtained above was measured. For 7075 alloy, 4 extruded rods of φ25
After being held at 70°C for 2 hours, it was water-cooled and aged at 120°C for 12 hours, and its tensile strength was measured. The result is the first
It is also shown in the table.

[Margin below]

From the results in Table 1, the alloy of the present invention can be hollow extruded using a combination die, and the obtained extruded material weighs 50 kg.
It was confirmed that it had a tensile strength exceeding f/-. On the other hand, the 7N01.7003 alloy had poor strength, and the 7075 alloy could not be extruded as described above.

that's all 205

Claims (1)

[Claims] Mg: 1.3-2.0wt%, Zn: 5.0-8.0w
t%, Cu: 0.4-1.0wt%, Zr: 0.1-0
．． A high-strength aluminum alloy that can be hollow extruded using a combination die, characterized in that the aluminum alloy contains 2 wt% and the balance consists of aluminum and unavoidable impurities.