JPH02250937A - Grayly developing aluminum alloy - Google Patents

Abstract

PURPOSE:To obtain the age hardening type Al alloy developing into bluish dark gray free from color shade by adding specified amounts of Si, Mg and Ni to an Al-Fe series alloy. CONSTITUTION:The Al alloy contains, by weight, 0.80 to 2.2% Fe, 0.40 to 1.2% Si, 0.25 to 0.7% Mg and 0.05 to 1.0% Ni, and at need, contains each 0.05 to 1.0% Co and/or Cu and the balance Al. In the Al alloy, Fe is the main element developing into gray by anodic oxidation treatment. Si and Mg impart age hardenability and lower limit or more is required respectively for obtaining prescribed hardness, but, the objective color tone can not be obtd. when the content of Si reaches to the upper limit or more, and in Mg, extrudability is deteriorated for the upper limit or more. Ni stably imparts objective color tone without the generation of color shade, but the effect is eliminated for the lower limit or less and the effect is saturated for the upper limit or more.

Description

[Detailed description of the invention] [Purpose of the invention]

(Industrial Application Field) The present invention relates to a gray-colored aluminum alloy containing Fe as the main coloring component, and more specifically, the present invention relates to a gray-colored aluminum alloy that is colored uniformly to a deep bluish gray with no color unevenness by anodizing treatment. Moreover, it relates to age-hardening aluminum alloys that have excellent extrudability, strength, and corrosion resistance, and in particular, it relates to gray-coloring aluminum alloys that are used to color extruded aluminum shapes gray at the anodizing stage. . (Prior art) Aluminum products such as sash materials, panel materials, and building materials such as gates are required to be available in a variety of colors.
There is also a strong demand for gray. Among grays, there is a strong demand for grays with strong bluish tones and dark tones, rather than pale, reddish, or yellowish ones. Conventionally, methods for surface-treating and coloring aluminum alloys include: - using numerical alloys to obtain the desired color by applying special bath compositions and treatment conditions according to the color, and natural coloring. A method of obtaining each color tone by anodizing using an alloy is known. (Problems to be Solved by the Invention) However, among the above methods, in the former method using a numerical alloy, it is very difficult to finish in an achromatic color or a dark tone even among grays. On the other hand, the latter method, which utilizes natural color development through anodic oxidation treatment, is generally highly weather resistant and corrosion resistant, and thus has been increasingly used in construction materials and the like in recent years. However, the color tone after the anodic oxide film treatment changes depending on the type and amount of added alloying elements, heat treatment method, anodization treatment method, etc., so it is necessary to make the color tone uniform and adjust the balance between the various characteristics of the alloy and the desired color tone. Alloy component design is generally difficult. That is, Al with Si added as a coloring component in AM
It is known that -5i series alloys or A-31-Mg series alloys made into age-hardening alloys by adding Mg to them develop a gray color when anodized. To obtain this, the Si content in the alloy must be increased, and an increase in Si content of 81% impairs the corrosion resistance and weather resistance of the alloy. Furthermore, these alloys develop a strong yellowish or reddish gray color when subjected to anodizing treatment, making it impossible to obtain the highly desired clear gray tone with a bluish tinge. In addition, with Al-Fe alloys containing Fe as a color-forming component, a deep gray tone with a bluish tinge can be obtained by normal alumite treatment in a sulfuric acid solution, but
In addition to the type of alloy that does not age harden, the intermetallic compound that is the coloring element of this system is unstable, and it is difficult to control its distribution state and particle size uniformly, so color unevenness is likely to occur. There was a problem. In addition, when Fe is added as a coloring component to an All-Mg-3i alloy, which is an age-hardening alloy, not only the desired dark gray tone cannot be obtained, but also the age-hardening property deteriorates due to the addition of Fe. However, there were concerns that sufficient strength would not be obtained even after heat treatment, so no examples have been put into practical use. This is because Fe is more likely to form An-Fe-3i intermetallic compounds than to form Al16 Fe, which is a color-forming element, so even if Fe is added, AM6 Fe, which is a color-forming element, is not formed much, and hardening is difficult. This is because it is thought that as a result of reducing the element Mg2Si, the color tone will hardly be improved and the strength will deteriorate. (Object of the Invention) The present invention has been made to solve the above-mentioned problems of conventional gray-colored aluminum alloys. The purpose of the present invention is to provide an age-hardening aluminum alloy that uniformly develops a dark gray color with a slight bluish tinge, and has excellent extrudability, strength, corrosion resistance, and weather resistance.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present inventor has determined that alloy components, heat treatment methods, etc. can be used to improve color tone, stability, and uniformity of color developed by anodizing treatment, as well as extrudability and age hardening properties. As a result of careful consideration of the effect on color, etc., we found that using Fe as the main coloring component is the most effective way to obtain the desired achromatic color with no reddish or yellowish tint, or a deep gray tone with a bluish tinge. Regarding the problems of non-heat treatability and color unevenness of An-Fe alloys, it is possible to give age hardenability by adding specific amounts of St and Mg to AM-Fe alloys, and roughly by adding Ni. By doing so, we have obtained completely new knowledge that the uneven coloring of Al--Fe alloys can be eliminated. In addition, Co and/or C
It has also been found that by testing a specific amount of u, a color tone with a strong bluish tinge or a dark gray tone can be obtained, and the stability of color development can also be increased. The gray-colored aluminum alloy according to the present invention is based on the above knowledge, and has Fe: 0.80 to 2 in weight%.
．． 2%, Si: 0.40~1.2%, Mg: 0.25~
0.7%, Ni: 0.05-1.0%, further Co: 0.05-1.0% and/or Cu: 0 as necessary
．． 05 to 1.0%, with the remainder consisting of Ai and unavoidable impurities. Below, the reasons for limiting the component values (wt%) of the gray-colored aluminum alloy according to the present invention will be described. Fe: 0.80-2.2% Fe forms An6 Fe and An-Fe-3i-based intermetallic compounds and is the main element that develops gray color by anodizing treatment, but if it is less than O, aO% A gray tone cannot be obtained, and conversely, if it exceeds 2.2%, not only the extrudability deteriorates, but also the age hardenability deteriorates, and the strength after aging decreases to be comparable to 6063 alloy. Strength cannot be obtained. Si: 0.40-1.2% St forms Mg2Si, which is necessary for age hardening, and has the effect of increasing strength due to single Sf, and 0.40%
If it is less than 1.2, it will not be possible to obtain the same strength as 6063 alloy.
If it exceeds %, extrudability will be inhibited, and due to the natural coloring effect of St during anodizing treatment, the color tone will be strong yellowish, making it impossible to obtain the desired bluish dark gray tone. Mg: 0.25-0.7% Mg is necessary together with the above-mentioned Si to obtain a certain strength, but if it is less than 0.25%, the effect cannot be expected;
If it exceeds 7%, extrudability deteriorates. Note that the influence of Mg on the color tone due to anodizing treatment is relatively small. Ni: 0.05 to 1.0% Nf is added to the alloy as an essential component because it has the effect of stably producing a more bluish tone or dark gray tone without color unevenness. If it is less than 0.05%, there is no effect, and if it exceeds 1.0%, the effect is saturated and there is no further effect of addition. Note that Ni has almost no negative effect on age hardenability if the other component compositions are within the above range, and even if Ni is added within the above range, the tensile strength and yield strength after age hardening treatment will be lower than that of Ni. The tensile strength and yield strength do not become lower than those without additives, but rather tend to slightly increase in tensile strength and yield strength depending on the amount of Ni added. Co: 0.05-1.0% Co has the same additive effect as Ni on the color tone after anodizing treatment, and by adding it as necessary, it can produce a darker gray tone and blue color. A strong gray tone is obtained. In addition, Co has little negative influence on age hardenability,
Even if added, Co does not cause a decrease in strength after age hardening treatment.Additionally, if Co is less than 0.05%, the addition has no effect.
If it exceeds 1.0%, the effect is saturated and there is no further effect of addition. Cu: 0.05-1.0% When Cu is further added to an alloy in which Fe, St, Mg, and Ni are in the above composition range, the gray color tone after anodizing becomes darker gray, and the hue becomes darker. The color becomes yellowish. Furthermore, by adding Cu, the tensile strength and yield strength after age hardening treatment increase. Therefore, Fe
, St. By adding Cu to an alloy in which Mg and Ni have the above-mentioned composition, fine adjustment of color tone and mechanical properties becomes possible. In addition, if Cu is less than 0.05%, there is no effect of adding it.
If it exceeds 1%, corrosion resistance will be significantly impaired. Although the alloy of the present invention has the above-mentioned composition, Ti or Zr can be added as another component. In other words, Ti and Zr have the function of refining the crystal grains of the ingot, and have the effect of making the color tone more uniform when the shape extruded from the billet is anodized, so if necessary, 0. About 1 to 0.2% of O may be added. The characteristics of the alloy of the present invention will be described in more detail below. The alloy of the present invention is a conventional An-Fe alloy that does not have age hardenability and has Fe as the main color forming component, but has age hardenability and color stability and uniformity.
By adding Mg to the Mg-St alloy and more Si than the conventional A-Mg-St alloy, such as 6063 alloy, Mg
g2Si is formed and used as an age-hardening element, and Fe
It can be said that the amount of Si and the amount of free Si for forming Mg2Si, which are insufficient due to the formation of ALL-Fe-3i-based gold metal compounds in the presence of , are compensated for by the above-mentioned line 31. In other words, the alloy of the present invention is the first gray color-forming alloy containing Fe as the main color-forming component that can be age-hardened, and can obtain strength comparable to that of 6063 alloy by applying artificial aging treatment. In addition, as mentioned above, Mg2S
Since i is a hardening element, it has excellent extrudability, high productivity during processing, and is an extremely easy-to-use alloy. In addition, due to the addition of St, the alloy of the present invention has Fe as the main coloring component, and is less likely to cause color unevenness and has excellent color tone stability. It is believed that the formation of Fe-3t-based gold metal compounds also contributes to improving the uniformity and stability of one color tone. Regarding the homogenization heat treatment temperature of the cast aluminum alloy billet of the present invention, if the temperature is lower than 400°C, the homogenization effect will be insufficient, and the occurrence of uneven color defects will become noticeable.
At temperatures exceeding 550°C, the coloring element AjL6Fe becomes Al3.
Since it changes to Fe, it becomes impossible to obtain a gray tone. Therefore, the homogenization heat treatment is desirably performed at a temperature range of 400° C. or higher and 550° C. or lower, and more preferably at 450° C. or higher in terms of uniformity of color tone. In addition, when surface-treating the extruded shape made of the alloy according to the present invention, degreasing and etching are performed. Smut removal is carried out according to a conventional method, and anodization treatment is also carried out by a commonly used method such as a sulfuric acid bath, and there are no particular limitations on the treatment conditions. (Example) Below, the superiority of the present invention will be shown more specifically by Examples and Comparative Examples. Casting aluminum alloys with each composition shown in Table 1 at a casting speed of 10
Cast into a 160mm billet at 0mm/min,
After homogenization heat treatment at 00℃XIO hours, 470℃
0 then 19 extruded into a C-shaped building material.
Artificial aging treatment at 0°C x 2.5 hours and degreasing9. Etching and smut removal were carried out according to conventional methods, and the current density was 1.50 A/dm' in a 130 g/sulfuric acid bath at 20°C.
Approximately 20Bm by performing anodization treatment for 50 minutes at
The color tone of the film was measured using a colorimeter manufactured by Suga Test Instruments, and expressed as L values and b values according to JIS Z8729. Here, regarding comparative alloys G and H, the present invention alloys A-F
Anodizing was performed in the same manner as above, and the color tone was measured in the same manner. Note that the L value represents brightness, and the higher the L value, the whiter the color, and the lower the L value, the darker the color.
The b value represents hue, with a high b8 value representing yellow, and a low b8 value representing blue; the closer the b value is to 0, the closer to an achromatic color. The results are shown in FIG. 1, and the alloys A to F of the present invention having components within the range specified in the present invention developed a deep gray color close to an achromatic color. In alloys A, B, and C, as the amount of Ni increased, the color developed into a deep gray with a strong bluish tinge. In addition, E with 10.20 wt% of Cu added to alloy B
In terms of color shading, the alloy produced a darker gray color than Alloy B, but in terms of hue, the b value was higher;
It was confirmed that the addition of Cu caused a tendency to become yellowish. Furthermore, alloy D, in which 0.20 wt% of Co was added to alloy B, and alloy F, in which 0.20 wt% of Co and Cu were each added to alloy B, developed a deeper blue gray color than alloy B. On the other hand, Comparative Alloy H containing Mn, which is generally considered to stabilize iron-based compounds, has a significantly lighter gray color.
Moreover, the color had a strong yellowish tinge. Table 2 shows the mechanical properties of each sample obtained through the same casting, homogenization heat treatment, extrusion 9 artificial aging treatment steps as the anodized sample. U ＼ As can be seen from this table, as the amount of Ni increases, the tensile strength and yield strength do not decrease, but rather tend to increase. In addition, in alloy E, which is obtained by adding Cu to alloy B, the tensile strength and yield strength after artificial aging treatment were approximately 2 kgf/mm' higher than those of alloy B. As described above, it was confirmed that all of the alloys A to F of the present invention have mechanical properties equivalent to those of T5 material, a 6063 alloy profile often used for construction purposes. It was confirmed that the corrosion resistance of these invention alloys was good, and that all of the A-F alloys satisfied KL2 in JIS H8601 (anodized film of aluminum and aluminum alloys).

【Effect of the invention】

As explained above, the gray coloring aluminum alloy according to the present invention can be produced by adding specific ranges of St, Mg and Ni to the Al-Fe alloy, thereby improving age hardenability and coloring to the alloy containing Fe as the main coloring component. In addition to imparting uniformity and stability, the color tone and mechanical properties can be controlled by adding Go and Cu singly or in combination as necessary. It has the same strength, has excellent extrudability, corrosion resistance, and weatherability, and develops an achromatic color or a dark gray color with a bluish tinge through anodizing treatment.
Moreover, it has many features such as no uneven color development and stable color tone even under variations in manufacturing conditions such as homogenization heat treatment conditions and extrusion temperature conditions, and has a wide range of uses, mainly for building materials. can be expected.

[Brief explanation of drawings]

FIG. 1 is a graph showing the influence of chemical composition on the color tone after anodizing treatment.

Claims (4)

[Claims] (1) In weight%, Fe: 0.80-2.2%, Si: 0
．． 40-1.2%, Mg: 0.25-0.7%, Ni:
A gray-colored aluminum alloy characterized by containing 0.05 to 1.0% of Al, with the remainder consisting of Al and unavoidable impurities. (2) In weight%, Fe: 0.80-2.2%, Si: 0
．． 40-1.2%, Mg: 0.25-0.7%, Ni:
A gray-colored aluminum alloy containing 0.05 to 1.0% Co, 0.05 to 1.0% Co, and the remainder consisting of Al and inevitable impurities. (3) In weight%, Fe: 0.80-2.2%, Si: 0
．． 40-1.2%, Mg: 0.25-0.7%, Ni:
A gray-colored aluminum alloy characterized by containing 0.05-1.0% of Cu, 0.05-1.0% of Cu, and the remainder consisting of Al and inevitable impurities. (4) In weight%, Fe: 0.80-2.2%, Si: 0
．． 40-1.2%, Mg: 0.25-0.7%, Ni:
0.05-1.0%, Co: 0.05-1.0%, Cu
: 0.05 to 1.0%, and the remainder consists of Al and unavoidable impurities.