JPH0525657A - Aluminum alloy sheet excellent in formability - Google Patents

Abstract

PURPOSE:To offer an aluminum sheet or an aluminum alloy sheet exceedingly improved in press formability compared to that of the conventional aluminum or aluminum alloy sheet and easily, stably and economically manufacturable on an industrial scale. CONSTITUTION:An aluminum alloy sheet in which the surface of an aluminum alloy sheet contg. >=4wt.% Mg has a plating layer of a single layer or >= two layers and its outer plating layer is constituted of ferrous plating with 1 to 50g/m<2> coating weight and excellent in formability having properties of >=30% elongation, <=0.13 sliding resistance and very small bearing dependency of the sliding resistance is manufactured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy sheet mainly used as a lightweight material for automobiles, and more particularly to an aluminum sheet or an aluminum alloy sheet having excellent press formability.

[0002]

_2. Description of the Related Art The weight reduction of automobiles has been actively promoted from the viewpoint of energy saving, CO ₂ global environmental problems, etc. Among them, aluminum or aluminum is used in view of material reliability, workability, recycling, etc. Aluminum alloys have been in the spotlight and are being used frequently in recent years.

However, since aluminum alloy sheets have different characteristics from those of steel sheets that have been widely used in the past, they have many problems when applied to automobile bodies. The representative is press molding. Taking SPCC as an example of a steel sheet, the elongation is 45%, and the limiting drawing LDR reaches 2.15 at an r value of 1.4, while the aluminum alloy sheet is A51.
Taking 82 as an example, the elongation is 30%, the r value is 0.7, and the LDR reaches only 1.8. As described above, the formability of the aluminum alloy plate is remarkably inferior, so that there is a great limitation in application to an automobile body. That is, the application example of the aluminum alloy plate to the vehicle body panel is limited to a lightly processed member such as a hood, and it has not been possible to apply it to a more complicated member accompanied by heavy working.

Since aluminum alloys have only recently been put to practical use in mass-produced products by press molding such as automobiles, no proposal or appropriate means for solving the above problems has been found, and these problems have been solved. At present, the products are produced while being held, and as a result, it is difficult to achieve the body weight reduction that is a social demand. .

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art. The press formability is remarkably improved as compared with the conventional aluminum or aluminum alloy sheet, and industrially. An object of the present invention is to provide an aluminum plate or an aluminum alloy plate that can be easily and stably manufactured economically.

[0006]

Means for Solving the Problems The inventors of the present invention have diligently studied the cause of poor press formability of an aluminum plate or an aluminum alloy plate (hereinafter referred to as an aluminum alloy plate), and as a result, a material typified by the above elongation characteristics In addition to being significantly inferior to the steel sheet, it was also found that the sliding characteristics of the aluminum alloy sheet are different from those of the steel sheet. In other words, as a result of examining the surface pressure dependence of the friction coefficient during sliding, as shown in FIG. 1, it is found that the surface pressure dependence of the aluminum alloy plate is very large compared to the surface pressure dependence of the steel plate being small. is there. On the low surface pressure side, the friction coefficient of the aluminum alloy sheet is about the same as the friction coefficient of the steel sheet, but as the surface pressure increases, the friction coefficient of the aluminum alloy sheet decreases and the difference with the steel sheet increases.

Based on this finding, the present inventors have completed the present invention based on the results of earnest studies to improve the press formability of the aluminum alloy sheet. That is, the present invention remarkably improves the press formability by improving the elongation characteristics of the aluminum alloy plate and at the same time applying iron-based plating containing iron as a main constituent on the surface of the aluminum alloy plate. That is, the present invention has a plating layer consisting of a single layer or two or more layers on the surface of an aluminum alloy plate containing 4% by weight or more of Mg, and the outer plating layer has a basis weight of 1 to 50 g / m ² of Fe system. To provide an aluminum alloy plate excellent in formability, which is characterized by being plated and has an elongation of 30% or more, a sliding resistance of 0.13 or less, and a surface pressure dependency of the sliding resistance is very small. Is.

[0008]

The present invention will be described in more detail. The aluminum alloy plate which is the material to be plated, which is one of the constituent features of the present invention, contains 4% by weight of Mg as an additive element for the reason described later.
% Or more. Further, the iron-based plating containing iron as a main constituent, which is another constituent of the present invention, is iron plating, iron-P plating, iron-C plating, iron-B plating, iron-zinc alloy plating, iron- Nickel alloy plating,
Or other iron alloy plating. The iron-based plating needs to be on the outermost surface that comes into contact with the mold during press forming of the aluminum alloy plate, and therefore, in the plating of a single layer or two or more layers, the outermost layer plating is limited to the iron-based plating. In the plating of two or more layers, the type of lower layer plating is not particularly limited, but iron-based or zinc-based plating is preferable. Also,
Any means such as electroplating, chemical plating, displacement plating, vapor deposition plating or cladding may be used as the plating means, and the means is not particularly limited.

When the above-mentioned iron-based plating is applied to the surface of an aluminum or aluminum alloy plate and the effect of improving press formability is expected, as shown in FIG. 1, friction is applied at a basis weight of the iron-based plating of lg / m ² or more. When the coefficient becomes 0.13 or less, the dependency of the friction coefficient on the surface pressure also decreases. Similarly, even if the basis weight exceeds 50 g / m ² , no further effect can be expected, and various raw materials and various energy are economically wasted. Therefore, the preferable basis weight of the iron-based plating is 1 to 50 g. / M ² . Further, even if the coefficient of friction is 0.13 or less, the elongation of the aluminum alloy plate material is low.
As shown in, the improvement in moldability is insufficient. Therefore, the elongation of the material is regulated to 30% or more, and the amount of Mg contained in the aluminum alloy plate to secure the elongation of 30% or more is regulated to 4% by weight or more, as is clear from FIG.

[0010]

EXAMPLES Next, the present invention will be specifically described based on Examples. Aluminum plate, especially 3.5% as a typical aluminum alloy plate used as a car body material
A Mg-containing aluminum alloy plate (elongation 28%) was used as a comparative material, and Mg contained 4.5% and 5.5% and had an elongation of 30%, respectively.
%, 35% aluminum alloy plate (Both thickness 1.0
mm) was subjected to various iron-based plating shown in Table 1. For these materials, the coefficient of friction was measured and, at the same time, cup molding was performed. The results are shown in Table 1. Also, the effects of the Fe-P coating weight and the surface pressure during sliding on the friction coefficient of the 5.5% Mg material were compared with the effects of the surface pressure on the friction coefficient of the steel plate (SPCC, plate thickness 1.0 mm). Shown in FIG. Further, FIG. 2 shows the influence of the Fe—P plating basis weight on the cup forming height of the above three types of aluminum alloy plates, and FIG. 3 shows the influence of the Mg addition amount on the elongation of the aluminum alloy plate (plate thickness 1.0 mm). Shown in.

Friction coefficient measurement test: Flat plate sliding, low viscosity oil coating Cup forming: 50 mmφ cylindrical punch, blank diameter 100
mm, low-viscosity oil coating Measure the forming height until the oil breaks

Table 1 ──────────────────────────────────── Mg amount elongation Plating friction coefficient Forming height Remarks (%) (%) Type Weight (mm) ─────────────────────────────────── ── 3.5 28 None 0.16 6 Comparative Example 3.5 28 Fe-0.1% P 5g / m ² 0.12 13 Comparative Example 4.5 30 None 0.16 8 Comparative Example 4.5 30 Fe-0.1% P 5g / m ² 0.12> 20, Through-throttle Invention Example 4.5 30 Fe-20% Zn 5g / m ² 0.12> 20, Through-drawing Example of invention 5.5 35 None 0.16 12 Comparative example 5.5 35 Fe-0.1% P 5g / m ² 0.115> 20, Through-drawing example of invention 5.5 35 Fe-20 % Zn 5g / m ² 0.125> 20, Drawing example 5.5 35 Fe-0.1% C 5g / m ² 0.12> 20, Drawing example ────────────────── ───────────────────

[0013]

As described above, according to the present invention, the press formability is remarkably improved by the combination of the compositional limitation of the aluminum plate or the aluminum alloy plate and the iron-based plating. As a result, it is possible to expect the effect of improving the production efficiency by reducing various troubles at the time of press forming and at the same time expanding the range of application of the aluminum alloy plate to the member having a complicated shape.

[Brief description of drawings]

1] Fe on friction coefficient of aluminum alloy plate
-P is a graph showing the influence of the coating weight and the surface pressure.

FIG. 2 is a graph showing the influence of material elongation and Fe-P plating areal weight on the cup forming height of an aluminum alloy plate.

FIG. 3 is a graph showing the influence of the amount of Mg on the elongation of an aluminum alloy plate.

Front Page Continuation (72) Inventor Makoto Imanaka 1 Kawasaki-cho, Chiba-shi, Chiba Within the Technical Research Division, Kawasaki Steel Co., Ltd. (72) Inventor Takaaki Hira 1 Kawasaki-cho, Chiba-shi, Chiba Kawasaki Steel Co., Ltd. Within the Research Headquarters (72) Inventor Yoshihiro Matsumoto 1 Kawasaki-cho, Chiba-shi, Chiba Kawasaki Steel Co., Ltd.Technical Research Division (72) Inventor Koichi Hashiguchi 1 Kawasaki-cho, Chiba-shi Kawasaki Steel Co., Ltd. In the Research Headquarters (72) Inventor, Motohiro Namba, Hirono Aluminum Industry Co., Ltd. 2-6-1, Marunouchi, Chiyoda-ku, Tokyo

Claims (1)

Claims: 1. An aluminum alloy plate containing 4 wt% or more of Mg has a plating layer consisting of a single layer or two or more layers on the surface thereof, and the outer plating layer has a basis weight of 1 to 50 g / Featuring m ² Fe-based plating, elongation of 30% or more,
An aluminum alloy sheet having a sliding resistance of 0.13 or less and a very small dependency of the sliding resistance on the surface pressure and having excellent formability.