JPH09143604A - Aluminium-magnesium-silicon base alloy excellent in extrudability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce an Al-Mg-Si base alloy in which the surface quality can be maintained while the high productivity is secured by the increase of the extruding rate and furthermore capable of realizing energy comsuption as for soaking treatment for the alloy for obtaining the above capacity. SOLUTION: This alloy has a compsn. contg., by weight, 0.35 to 0.80% Mg, 0.20 to 0.90% Si, 0.16 to 0.25% Fe, 0.01 to 0.20% Cu, 0.01 to 0.15% Ni and 0.01 to 0.02% Ti, and the balance aluminum with impurities, and, optionally, one or two kinds of <=0.15% Mn and <=0.10% Cr may be incorporated therein.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an Al-Mg-Si alloy having excellent extrudability, which is used for general building materials such as aluminum sashes and other structural materials.

[0002]

2. Description of the Related Art Al-Mg-Si alloys (J
(IS6000 series alloy) has high productivity because it has excellent extrudability, and is widely used for general building materials such as aluminum sashes and other structural materials. Further, recently, attempts have been made to increase the extrusion speed in the extrusion processing of the 6000 series alloy to further improve the productivity.

However, when the extrusion speed is increased, the insoluble Al-Fe-Si contained in the billet of the 6000 series alloy.
Particles are the origin and peeling and surface defects such as pickup occur in the extruded material. Therefore, in order to improve the productivity while maintaining the surface quality, it is necessary to control the content of Al-Fe-Si particles and the like. It was one of the important issues.

Therefore, a small amount of Mn is added to the 6000 series alloy, and the alloy is subjected to a soaking treatment at a high temperature to make Al-Fe-Si particles, which are the origin of surface defects, finer, and the particles are spread over the entire billet. Japanese Patent Publication No. 4-72899 reports an alloy capable of suppressing the occurrence of surface defects even if the extrusion speed is increased by evenly dispersing the alloy.

[0005]

However, when Mn is added to a 6000 series alloy to make Al-Fe-Si particles finer, in the step of soaking the billet of the alloy obtained by casting in a soaking process. Heating at a high temperature around 585 ° C for several hours was required. Therefore, although the above-mentioned alloy improves productivity in extrusion processing, it requires a large amount of energy and causes an increase in cost.

The present invention has been made in view of the above problems, and it is possible to maintain the surface quality while increasing the extrusion speed in the extrusion process to ensure high productivity, and
Al-Mg-S that can realize energy saving for soaking for finely homogenizing Al-Fe-Si particles
The purpose is to provide an i-based alloy.

[0007]

As a result of earnest research and experimentation, the present inventor has found that the above object is obtained by adding a predetermined amount of Ni to an Al-Mg-Si-based alloy having excellent extrudability as a base. The inventors have found that the above can be achieved, and have reached the present invention.

That is, according to the present invention, Mg: 0.35 to 0.
80 wt%, Si: 0.20 to 0.90 wt%, Fe: 0.
16 to 0.25 wt%, Ni: 0.01 to 0.15 wt%,
Cu: 0.01-0.20 wt%, Ti: 0.01-0.
Al-Mg-Si excellent in extrudability characterized by containing 02 wt% and the balance being aluminum and impurities
It is based on a system alloy. In addition to the above elements, Mn: 0.15 wt% or less, Cr: 0.10 wt%
You may contain any 1 type or 2 types of% or less.

In the above, Mg and Si are elements that contribute to improving the strength of the alloy. However, Mg is 0.35 wt%
%, Si is less than 0.20 wt%, the effect is poor, conversely Mg exceeds 0.80 wt%, Si is 0.9
If the content exceeds 0 wt%, the extrudability will decrease. Therefore, Mg is 0.35-0.80 wt% and Si is 0.20-
It must be contained in the range of 0.90 wt%. Particularly preferred lower limits of the content are Mg: 0.40 wt% and Si:
0.35 wt%, the upper limit is Mg: 0.75 wt%, S
i: 0.85 wt%

[0010] Fe forms insoluble Al-Fe-Si particles in the alloy that cause surface defects during extrusion molding, so it is preferable to suppress the content of Fe as much as possible. The lower the value, the higher the price of the alloy itself, and the more uneven the surface color due to anodic oxidation that may be performed after forming. Therefore, the lower limit of the Fe content is limited to 0.16 wt%.

On the other hand, when Al-Fe-Si particles are contained in the alloy, the particle size is fine, the particles are evenly distributed in the alloy, and the higher the α-conversion rate, the higher the probability of occurrence of surface defects. Will be lower. In the present invention, Ni is added to the 6000 series alloy to promote the refinement and alpha conversion of the Al-Fe-Si particles. However, if the Fe content is high, the addition of Ni also causes Al-Fe- The upper limit of the Fe content is 0.
Limited to 25 wt%.

Therefore, Fe must be contained in the range of 0.16 to 0.25 wt%. Particularly preferable Fe content is 0.18 wt% as the lower limit and 0.22 wt% as the upper limit.
It is.

Ni is insoluble in Al-
It is an element that promotes α-formation and miniaturization of Fe-Si particles. Therefore, if the Ni content is less than 0.01 wt%, the effect of promoting α-formation and refinement becomes poor. On the other hand, 0.15 wt
If it is contained in excess of%, not only the above effect is saturated but also the corrosion resistance of the alloy is lowered. Therefore, Ni is 0.01-0.
It must be contained in the range of 15 wt%. A particularly preferable lower limit of the Ni content is 0.03 wt% and an upper limit thereof is
It is 0.10 wt%.

Cu contributes to improving the strength of the alloy, but if its content is less than 0.01 wt%, its effect is poor, and if it exceeds 0.20 wt%, the effect is saturated. Also,
Ti contributes to the refinement of crystal grains, and its content is 0.01
If it is less than wt%, the effect is poor, and if it exceeds 0.02 wt%, the effect is saturated.

Mn, which is optionally added, has the same A content as Ni.
Although it contributes to miniaturization of 1-Fe-Si particles,
Even if added over 0.15 wt%, the miniaturization effect is saturated. Further, Cr contributes to improving the strength of the alloy by refining the crystal grains, but even if added in excess of 0.10 wt%, the refining effect is saturated and further addition causes economical waste. . Particularly preferred lower limit of the content of Mn and Cr containing Mn and Cr is 0.02 wt%,
Cr: 0.01 wt%, the upper limit is Mn: 0.12 wt
%, Cr: 0.10 wt%.

The Be element may be added to the alloy according to the present invention for the purpose of improving the efficiency of the aging treatment performed after extrusion molding. Specifically, the Be content is 0.0005.
It is preferable to add it in the range of 0.15 wt%, and the particularly preferable lower limit of the Be content is 0.001 wt%.
%, And the upper limit is 0.10 wt%.

In producing the alloy according to the present invention, each element is adjusted and melted according to a conventional method so as to be in the above content range, and then cast into a billet having a predetermined shape. Next, the billet is homogenized, and Al- contained in the alloy is
A soaking process is performed in order to make the Fe-Si particles finer, to be α, and to disperse them uniformly in the alloy. Although the temperature condition of the soaking can be arbitrarily selected, in the present invention, by adding Ni, the Al—Fe—Si particles can be made finer and can be made α by a soaking at a relatively low temperature. , 550 to 570 ℃ in consideration of time and energy cost
It is preferable to perform soaking at a temperature of 1.5 to 3 hours.

[0018]

Next, an embodiment of the present invention will be described.

As shown in Table 1, six types of samples A to F within the composition range of the present invention and three types of samples G to I out of the composition range were prepared as comparative examples. . Each of the above-mentioned samples was formed into a billet having a predetermined shape by casting, after preparing and dissolving each composition according to a conventional method. The billet used in this example had a diameter of 6 inches and a length of 650 mm.

[0020]

[Table 1]

Next, the Al--Fe--Si particles are refined and α
A soaking process was carried out in order to form and uniformly disperse in the billet. The conditions of the soaking treatment were set to various values shown in Table 2 below in order to confirm a significant difference from the comparative example.

[0022]

[Table 2]

After the soaking treatment, the billet is once cooled, but the method for cooling the billet is not particularly limited.

Next, the billet subjected to the soaking treatment under the above respective conditions was extruded according to a conventional method. In this example, the direct extrusion method was adopted, and the billet heated to 470 ° C. was extruded into an extruded profile having a height of 47 mm and a width of 29 mm. The extrusion speed was set to 40 m / min.

Next, the extruded material was subjected to an aging treatment at 200 ° C. for 3 hours to obtain a finished extruded material.

The surface of the extruded material thus obtained was visually observed to evaluate the surface quality of the extruded material in each alloy.
The results are shown in Table 3 below. In order to obtain the correlation between the α-gelatinization rate of Al-Fe-Si particles contained in the billet before extrusion and the surface quality after extrusion, the α-gelatinization rate of the billet was measured. It writes according to Table 3.

[0027]

[Table 3]

As can be seen from the results in Table 3, in the billet having the composition range according to the present invention, the Al-Fe-Si particles were completely converted into α, regardless of the temperature and time of soaking, and the billet after extrusion was Almost no defects were observed on the surface of the extruded material,
It was confirmed that the surface quality was better than that of the comparative example.

[0029]

According to the present invention, the 6000 series alloy contains a predetermined amount of Ni, depending on the above. Therefore, even if the soaking temperature as low as 550 to 570 ° C., the Al-- The Fe-Si particles are promoted to be finer and to be alpha, and surface defects do not appear in the extruded material even if the extrusion speed in the extrusion of the billet is increased. Therefore, according to the alloy of the present invention, high productivity can be secured while maintaining the surface quality, and energy saving can be realized.

Claims (2)

[Claims] 1. Mg: 0.35 to 0.80 wt% Si: 0.20 to 0.90 wt% Fe: 0.16 to 0.25 wt% Ni: 0.01 to 0.15 wt% Cu: 0.01 -0.20 wt% Ti: 0.01-0.02 wt%, the balance being aluminum and impurities, and an Al-Mg-Si based alloy excellent in extrudability. 2. Mg: 0.35 to 0.80 wt% Si: 0.20 to 0.90 wt% Fe: 0.16 to 0.25 wt% Ni: 0.01 to 0.15 wt% Cu: 0.01 -0.20 wt% Ti: 0.01-0.02 wt%, Mn: 0.15 wt% or less Cr: 0.10 wt% or less Any one or two types are contained, and the balance is aluminum and An Al-Mg-Si based alloy excellent in extrudability characterized by comprising impurities.