JPH0525572A - Corrosion resisting aluminum alloy clad material for high temperature forming - Google Patents

Abstract

PURPOSE:To obtain an aluminum alloy clad material suitable for a product member used in a marine atmosphere, such as ships, excellent in high temp. formability, and having superior strength and corrosion resistance. CONSTITUTION:The material is a corrosion resisting aluminum alloy clad material for high temp. forming in which an Al alloy containing, by weight, 0.5-7.5% Mg and also containing one or >=2 elements among Cr, Mn, Zr, Ti, Fe, Ni, Cu, and Zn as selective elements is used as a core material and an Al alloy containing 0.1-2.5% Zn, <=1% Fe, and <=1% Si and also containing one or >=2 elements among Mg, Cu, Cr, Mn, Zr, and Ni as selective elements is used as a cladding material and one side or both sides of the core material are clad with the cladding material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy clad material excellent in corrosion resistance and formability, which is suitable for materials which are formed by high temperature forming and then subjected to surface treatment or not. In particular, it is suitable for a product member used in a marine atmosphere such as a ship.

[0002]

2. Description of the Related Art Ships, particularly relatively small fishing boats, leisure boats, and the like, are often used after being coated with a steel sheet after press forming. However, steel sheets have low corrosion resistance after coating scratches and peeling, and regular repainting was required, so in recent years, the number of ships employing FRP hulls has increased rapidly. However, these F
Since it is difficult to process scraps of the RP hull after the life of the ship has expired, environmental pollution problems due to leaving the abandoned ship at the seaside or the like have become apparent.

[0003]

Under the above-mentioned background, as a hull structural material of these ships, an aluminum plate material which is more excellent in corrosion resistance than a steel plate and more excellent in scrap processing and recycling than FRP is drawing attention. . For structural members exposed to such a marine atmosphere, Al-Mg based alloys having excellent corrosion resistance, strength and formability are often used. On the other hand, aluminum structural materials generally tend to be inferior in formability to steel plates, which is an obstacle in determining the shape of products. Therefore, warm forming or high temperature forming has been studied as a technique for forming an aluminum plate material into a more complicated shape. In this technique, a part or the whole of a material and a mold are heated to 100 to 500 ° C., and a molding process is performed under the condition that the moldability of the material is improved.
This is a technique suitable for forming members that require high processing. Further, also in this high temperature molding, bulge molding using pneumatic pressure or hydraulic pressure is being studied in addition to normal press working. According to this method, pneumatic or hydraulic pressure is used as the pressurizing medium, so that a male mold is not required, and the material is uniformly deformed, so that the molding limit is improved. However, when the above Al—Mg-based alloy is subjected to high temperature molding, concentration and oxidation of Mg atoms occur on the surface to give a greenish black color, which is not preferable in appearance. Further, even when coating is applied, this oxide layer lowers the coating film adhesion, resulting in deterioration of the corrosion resistance of the product. Such an oxide film needs to be removed chemically and mechanically, which has been a factor that hinders productivity. The formation of this oxide film is affected by temperature and processing time,
This is often a particular problem in press molding by a hydraulic press or bulge processing, which has a relatively low molding speed. In view of these problems, the present invention has developed a corrosion-resistant aluminum alloy clad material for high-temperature forming, which is suitable for use as a member such as an outer plate of a relatively small ship that is formed at high temperature.

[0004]

The present invention contains 0.5 to 7.5 wt% of Mg as an essential element, and further contains Cr0.0
3 to 0.55 wt%, Mn 0.03 to 2.5 wt%, Zr
0.03 to 0.25 wt%, Ti 0.005 to 0.35 wt
%, Fe 0.03 to 0.5 wt%, Ni 0.03 to 1.5
One or two or more of wt% are selectively contained, and the balance is Zn0.1
~ 2.5wt%, Si≤1wt%, Fe≤1wt%, balance A
1. A corrosion-resistant aluminum alloy clad material for high-temperature forming, which is characterized by clad with a skin material made of 1 and containing 0.5 to 7.5 wt% of Mg as an essential element,
Further, Cr 0.03 to 0.55 wt%, Mn 0.03 to
2.5 wt%, Zr0.03-0.25 wt%, Ti0.0
05-0.35wt%, Fe0.03-0.5wt%, Ni
One or both of 0.03 to 1.5 wt% of the core material is selectively contained, and the balance is made of Al, and Zn0.1 to 2.5 wt%, Si ≦ 1 wt%, Fe ≤
Contains 1 wt%, Cu 0.1-1 wt%, Mg 0.1-
2 wt%, Mn 0.1-2.5 wt%, Cr 0.1-1.0
wt%, Zr0.1-0.3wt%, Ni0.1-1.5wt
%, One or two or more of them are selectively contained, and a corrosion-resistant aluminum alloy clad material for high-temperature forming is clad with a skin material whose balance is Al, and Mg0. 5 to 7.5 wt%,
And Cu 0.01-0.5 wt%, Zn 0.02-2.5
Contains either one or two of wt%, and Cr
0.03 to 0.55 wt%, Mn 0.03 to 2.5 wt%,
Zr 0.03 to 0.25 wt%, Ti 0.005 to 0.3
5wt%, Fe0.03-0.5wt%, Ni0.03-
One or more of 1.5 wt% of the core material is selectively contained, and the balance is made of Al.
n0.1-2.5 wt%, Si ≦ 1 wt%, Fe ≦ 1 wt%,
A corrosion-resistant aluminum alloy clad material for high-temperature forming, characterized in that a clad material having the balance of Al is clad is defined as claim 3, containing 0.5 to 7.5 wt% of Mg as an essential element, and Cu 0.01 to 0. 0.5 wt%, Zn 0.02
It contains any one or two of 2.5 wt%, and further contains Cr 0.03 to 0.55 wt% and Mn 0.03 to 2.5.
wt%, Zr 0.03 to 0.25 wt%, Ti 0.005
0.35 wt%, Fe0.03-0.5 wt%, Ni0.0
One or two or more of 3 to 1.5 wt% are selectively contained, and the balance is made of Al on one or both sides of the core material.
Zn 0.1-2.5 wt%, Si ≦ 1 wt%, Fe ≦ 1 wt%
Containing 0.1 to 1 wt% Cu and 0.1 to 2 wt% Mg
%, Mn 0.1 to 2.5 wt%, Cr 0.1 to 1.0 wt
%, Zr 0.1 to 0.3 wt%, Ni 0.1 to 1.5 wt%
1 or 2 or more of them are selectively contained, and the balance is A
A corrosion-resistant aluminum alloy clad material for high-temperature molding, which is characterized in that a skin material made of 1 is clad.

[0005]

The reason for limiting the alloy components in the present invention will be described below. First, the alloy composition of the core material will be described. Mg
Dissolves in the material and has the effect of improving the formability by improving the strength and ductility of the material. Especially when heated to a high temperature, it has the effect of promoting uniform deformation during the forming process of the material, and as a result, the forming limit is improved. It also has the effect of increasing the static strength as a product, preventing deformation due to external force, and preventing temporal changes (creep deformation, etc.) when the hull or the like receives external pressure for a long time. Further, the product intended by the present invention has an effect of improving the corrosion resistance of the material when the skin material is damaged due to environmental factors or the like. If the addition amount is less than 0.5 wt%, these effects are not sufficient, and if it exceeds 7.5 wt%, a coarse Al-Mg-based compound is generated in the material, resulting in moldability,
Deteriorates corrosion resistance. Cu and Zn have the effect of improving the formability by improving the strength and ductility of the material by forming a fine compound in the material together with Mg. However, for both elements, the corrosion resistance of the raw materials tends to be slightly lowered, and in products in which the corrosion resistance of the core material poses a problem, it is preferable to decide addition or non-addition in consideration of the shape and use environment. If the addition amount is less than the respective lower limits, the effect of improving the formability cannot be expected so much, and if the addition amount exceeds the upper limit, the corrosion resistance is significantly reduced. Cr, Mn, Zr, Ti, Fe, and Ni each generate a fine compound in the material together with Al, and have the effect of refining the material structure to improve strength and formability and also improve the corrosion resistance of the material. Therefore, one or more of these elements should be selectively added. If the addition amount is less than the lower limit, these effects are not sufficient, and if the addition amount is more than the upper limit, a coarse compound is generated in the material to deteriorate the formability. Regarding the contained elements other than the above, Si is mainly used as an impurity element, but Si produces a Mg-Si-based compound together with Mg at the time of alloy casting, reducing the substantial addition amount of Mg and reducing its effect. In addition, the content is preferably low in order to deteriorate the corrosion resistance. However, reducing the Si content means increasing the purity of the metal used, which leads to an increase in manufacturing cost. Therefore, it is industrially unfavorable to reduce the Si content more than necessary. From these facts, the Si content should be 0.5 wt% or less. Regarding other trace elements, if the content is 0.05 wt% or less, the characteristics of the present invention are not adversely affected. Therefore, B may be added for the purpose of improving castability.
It is possible to add trace elements such as e, B, etc. or misch metal, which may be added for improving formability, in the range of 0.05 wt% or less. In addition, other elements mixed during the production may be 0.5 wt% or less.

Next, alloy components of the skin material will be described. Zn
Increases the potential difference between the core material and the skin material by making a solid solution to make the skin material less base potential, and as a result, preferential corrosion of the skin material relatively when exposed to a corrosive environment during use. Occurs, and the effect of improving the corrosion life of the entire member is exhibited. If less than 0.1 wt%, this effect is not sufficient,
If it exceeds 2.5, the corrosion resistance is significantly reduced. Fe and Si are mainly contained as impurities, but if each of these elements exceeds 1 wt%, coarse crystallized substances are formed in the material to impair formability and corrosion resistance. Therefore, the content of these elements should be 1 wt% or less. C
u, Mg, Mn, Cr, Zr, and Ni have the effect of improving the formability of the material at high temperatures. If the amount is less than the lower limit, these effects are not sufficient, and if the amount exceeds the upper limit, the moldability may be decreased. However, these elements may slightly lower the corrosion resistance in the use environment, so it is necessary to decide whether to add or not to add as necessary. If the amount of other elements mixed in during manufacturing is 0.5 wt% or less, the characteristics of the material of the present invention are not adversely affected. The clad material of the present invention can be manufactured by a conventional method.

[0007]

EXAMPLES An example of the present invention will be described below.
Alloys of a core material and a skin material having the chemical composition shown in Table 1 were formed by DC casting into an ingot having a thickness of 400 mm and a width of 2300 mm.
The skin material was chamfered on both sides of each ingot by 5 mm, homogenized at 600 ° C for 8 hours, and then hot-rolled and cold-rolled to 10
mm plate material. For the core material, after ingot cutting both sides of the ingot by 10 mm,
440 ℃ x 6 as a 400 mm laminated material by combining the leather materials
After homogenizing at h + 520 ℃ × 8h, and then hot rolling and cold rolling by the usual method to make a clad material with a thickness of 1mm, this plate material is annealed at 500 ℃ × 10sec. It was made of wood. Among the comparative examples, for the material without clad, a 380 mm ingot after chamfering was homogenized, hot-rolled, cold-rolled, and annealed in the same manner as the clad material, and a 1-mm thick sample was used. It was a plate material. A 400 × 400 mm test piece was processed from the obtained plate material and subjected to a warm molding bulging test. In the warm molding bulging test, molding was performed at 450 ° C. using a 200 mmφ ball head punch, and the molding limit height without cracking was determined. Forming speed is 1 mm as punch moving speed
/ Sec. Further, the degree of discoloration of the material surface after molding was visually checked. The results are also shown in Table 1.
In addition, the test material is used as a heating simulation during high temperature forming.
After heating at 0 ℃ × 5min. And cooling to room temperature, width 50mm
× A test piece with a length of 100 mm is cut out, one side is sealed, and the corrosion resistance of the unsealed surface is tested by the CASS test 720.
The evaluation was carried out by a time corrosion test. The evaluation was based on the maximum pitting depth of the corrosion test. The results are also shown in Table 1.

[0008]

[Table 1]

As is clear from the table, the aluminum alloy clad material of the present invention does not show discoloration when subjected to high temperature forming, and has excellent warm formability and excellent corrosion resistance after heating, as compared with the comparative material. I understand.

[0010]

EFFECTS OF THE INVENTION According to the present invention, excellent warm forming workability, high strength and corrosion resistance after working, and features such as no surface discoloration after working and the like, which is a remarkable industrial effect, It plays.

Claims (4)

[Claims] 1. Mg 0.5 to 7.5 wt% as an essential element
Containing Cr, 0.03 to 0.55 wt% Cr, Mn
0.03 to 2.5 wt%, Zr 0.03 to 0.25 wt%,
Ti 0.005 to 0.35 wt%, Fe 0.03 to 0.5
wt%, Ni 0.03 to 1.5 wt%, selectively containing one or more of Ni and 0.1 to 2.5 wt% Zn, Si ≤ 1 wt% on one or both sides of the core material with the balance being Al.
%, Fe ≦ 1 wt%, and a clad material made of Al, the balance being Al, and a corrosion resistant aluminum alloy clad material for high temperature molding. 2. 0.5 to 7.5 wt% Mg as an essential element
Containing Cr, 0.03 to 0.55 wt% Cr, Mn
0.03 to 2.5 wt%, Zr 0.03 to 0.25 wt%,
Ti 0.005 to 0.35 wt%, Fe 0.03 to 0.5
wt%, Ni 0.03 to 1.5 wt%, selectively containing one or more of Ni and 0.1 to 2.5 wt% Zn, Si ≤ 1 wt% on one or both sides of the core material with the balance being Al.
%, Fe ≦ 1 wt%, and Cu 0.1 to 1 wt%, M
g 0.1-2 wt%, Mn 0.1-2.5 wt%, Cr0.
1-1.0 wt%, Zr0.1-0.3 wt%, Ni0.1
A corrosion-resistant aluminum alloy clad material for high-temperature forming, characterized in that it selectively contains one or more of 1.5 wt% to 1.5 wt%, and clad a skin material with the balance being Al. 3. Mg 0.5 to 7.5 wt% as an essential element
Containing 0.01 to 0.5 wt% Cu, Zn0.0
2 to 2.5 wt% containing any one or two,
Further, Cr 0.03 to 0.55 wt%, Mn 0.03 to
2.5 wt%, Zr0.03-0.25 wt%, Ti0.0
05-0.35wt%, Fe0.03-0.5wt%, Ni
One or both of 0.03 to 1.5 wt% of the core material is selectively contained, and the balance is made of Al, and Zn0.1 to 2.5 wt%, Si ≦ 1 wt%, Fe ≤
A corrosion-resistant aluminum alloy clad material for high-temperature forming, characterized by clad with a skin material having 1 wt% and the balance being Al. 4. Mg 0.5 to 7.5 wt% as an essential element
Containing 0.01 to 0.5 wt% Cu, Zn0.0
2 to 2.5 wt% containing any one or two,
Further, Cr 0.03 to 0.55 wt%, Mn 0.03 to
2.5 wt%, Zr0.03-0.25 wt%, Ti0.0
05-0.35wt%, Fe0.03-0.5wt%, Ni
One or both of 0.03 to 1.5 wt% of the core material is selectively contained, and the balance is made of Al, and Zn0.1 to 2.5 wt%, Si ≦ 1 wt%, Fe ≤
Contains 1 wt%, Cu 0.1-1 wt%, Mg 0.1-
2 wt%, Mn 0.1-2.5 wt%, Cr 0.1-1.0
wt%, Zr0.1-0.3wt%, Ni0.1-1.5wt
%, A corrosion-resistant aluminum alloy clad material for high-temperature molding, characterized in that it selectively contains one or more kinds of Al and the remainder is clad with Al.