JP2949673B2 - Iron-plated aluminum alloy sheet with excellent formability and adhesion - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

_2. Description of the Related Art Lightening of automobiles has been actively promoted from the viewpoints of energy saving, global environmental issues due to CO _2, etc. Among them, aluminum or aluminum has been considered in terms of material reliability, workability, recycling and the like. Aluminum alloys have been in the limelight and have been widely used in recent years.

[0003] However, aluminum alloy sheets have different characteristics as compared with steel sheets that have been frequently used in the past, and therefore have many problems when applied to automobile bodies. A typical example is press molding. Taking SPCC as an example of a steel sheet, the limit drawing LDR reaches 2.15 at an elongation of 45% and an r value of 1.4, whereas the aluminum alloy sheet has an A51 of A51.
Taking 82 as an example, the LDR reaches only 1.8 at an elongation of 30% and an r value of 0.7. As described above, since the formability of the aluminum alloy sheet is remarkably inferior, application to an automobile body has been greatly restricted. 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 cannot be applied to a more complicated member with a strong processing.

Since aluminum alloys have only recently been put into practical use as 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, production is carried while holding the vehicle, and as a result, it has become difficult to achieve a reduction in body weight, which is a social requirement.

[0005]

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

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies on the cause of poor press formability of an aluminum plate or an aluminum alloy plate (hereinafter referred to as an aluminum alloy plate). Was found to be remarkably inferior to steel plates and that the sliding properties of aluminum alloy plates were different from those of steel plates. That is, as a result of examining the surface pressure dependency of the friction coefficient during sliding, as shown in FIG. 1, the surface pressure dependency is extremely large in the aluminum alloy plate, while the surface pressure dependency is small in the steel plate. is there. On the low surface pressure side, the friction coefficient of the aluminum alloy sheet is almost 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 from the steel sheet increases.

Based on this finding, the present inventors have made intensive studies to improve the press formability of the aluminum alloy sheet, and have completed the present invention. That is, the present invention significantly improves the press formability by improving the elongation characteristics of the aluminum alloy plate and simultaneously applying iron-based plating containing iron as a main component to the surface of the aluminum alloy plate, and further improves the baseability of the iron-based plating. By providing a thin zincate layer, the adhesion of the plating layer is improved. That is, the present invention is characterized by having a zincate layer on the surface of an aluminum alloy plate containing 4% by weight or more of Mg and a Fe-based plating layer having a basis weight of 3 to 20 g / m ² thereon, and having an elongation of 30% or more. , Sliding resistance is 0.13
It is an object of the present invention to provide an aluminum alloy plate which is excellent in both formability and plating adhesion, which has the following characteristics and has very small surface pressure dependence of sliding resistance.

[0008]

The present invention will be described in more detail. The aluminum alloy plate to be plated, which is one of the constituent elements of the present invention, contains 4% or more by weight of Mg as an additive element for the reason described later. The iron-based plating containing iron as a main component, which is another component of the present invention, includes iron plating, iron-P plating, iron-C plating, iron-B plating, iron-zinc alloy plating, and iron-plating. Nickel alloy plating,
Or it refers to other iron alloy plating. The means for plating may be any means such as electroplating, chemical plating, vapor deposition plating or cladding, and the means is not particularly limited. Further, as a zincate layer serving as a base of the iron-based plating layer, Zn, Zn
-Ni, Zn-Fe, Zn-Ni-Cu, etc. may be used.

When the above-mentioned iron-based plating is applied to the surface of an aluminum or aluminum alloy plate and an effect of improving press formability is expected, as shown in FIG. 1, friction is required at a basis weight of the iron-based plating of lg / m ² or more. The coefficient is stabilized at 0.13 or less, and at the same time, the dependency of the friction coefficient on surface pressure is reduced. Further, even if the friction coefficient is 0.13 or less, if the elongation of the aluminum alloy sheet material is low, the improvement of the formability becomes insufficient as shown in FIG. Therefore, the elongation of the raw material is specified to be 30% or more, and the Mg content contained in the aluminum alloy plate is specified to be 4% by weight or more as apparent from FIG. Since the iron-plated aluminum alloy sheet having the above-described configuration shows much better formability than a conventional aluminum alloy sheet, it can be applied to parts having complicated shapes and strong processing. However, the peeling of the plating layer, which is a concern during strong working, can be suppressed by providing a zincate layer on the underlayer as compared with the iron-based single-layer plating as shown in FIG. In this case, it is preferable that the amount of the zincate layer attached is small. Further, in the surface layer structure composed of the zincate layer and the iron-based plating layer, if the iron-based plating weight is less than 3 g / m ² or more than 20 g / m ² , the plating adhesion is deteriorated, so that the iron-based plating weight is 3 to 20 g / m ^2. It was limited to the range of m ^2.

[0010]

Next, the present invention will be specifically described based on examples. 3.5% as an aluminum plate, especially a typical aluminum alloy plate used as an automobile body material
A Mg-containing aluminum alloy plate (elongation: 28%) was used as a comparative material and contained 4.5% and 5.5% of Mg, and each had an elongation of 30%.
%, 35% aluminum alloy plate (both plate thickness 1.0%
mm) was subjected to various iron-based platings shown in Table 1. For these materials, cup molding was performed at the same time as the coefficient of friction was measured. Table 1 shows the results. In addition, the effects of the basis weight of Fe-P plating and the surface pressure during sliding on the friction coefficient of 5.5% Mg material were compared with those of the steel plate (SPCC, plate thickness 1.0 mm). FIG. FIG. 2 shows the effect of the basis weight of Fe-P plating on the cup forming height of the above three types of aluminum alloy plates, and FIG. 3 shows the effect of the amount of Mg added on the elongation of the aluminum alloy plate (plate thickness: 1.0 mm). FIG. 4 shows the plating adhesion of a 5.5% Mg-added aluminum alloy plate. The plating adhesion was evaluated by applying a tape to the sliding surface after the sliding test at a surface pressure of 4 kgf / mm ² and evaluating the degree of blackening of the tape after peeling off the tape from 0 to 5. The higher the rating, the greater the amount of peeling and the darker the color.

Friction coefficient measurement test: flat plate sliding, low-viscosity oil-coated oil Cup molding: 50 mmφ cylindrical punch, blank diameter 100
mm, the height of molding until the low viscosity oil coating oil breaks

Table 1 ──────────────────────────────────── Mg content Elongation Zincate plating Friction coefficient Molding height Remarks (%) (%) Type Type Weight (mm) ─────────────────────────────────── ─ 3.5 28 None None 0.16 6 Comparative Example ──────────────────────────────────── 3.5 28 Zn Fe- 0.1% P 5g / m ² 0.12 13 Comparative example ──────────────────────────────────── 4.5 30 None None 0.16 8 Comparative example ──────────────────────────────────── 4.5 30 Zn-Ni Fe-0.1% P 5g / m ² 0.12> 20, Draw-out Invention example ──────────────────────────────────── 5.5 35 None None 0.16 12 Comparative Example ──────────────────────────────────── 5.5 35 Zn-Ni Fe-0.1 % P 5g / m ² 0.115> 20, Draw-out Invention example ──────────────────────────────────── 5.5 35 Zn Fe-20% Zn 5g / m ² 0.125> 20, Draw-through Invention example ────────────────────────────── ────── 5.5 35 Zn-Fe Fe-0.1% C 5g / m ² 0.12> 20, Draw-through Invention example ────────────────────── ──────────────

[0013]

As described above, according to the present invention, both the adhesion of the plating layer and the press formability are remarkably improved by limiting the composition of the aluminum plate or aluminum alloy plate and by combining the zincate layer and the iron-based plating. As a result, the production efficiency can be improved by reducing various troubles such as breakage at the time of press molding and generation of stars due to the peeling powder of the plating layer, and at the same time, the effect of expanding the application range of the aluminum alloy plate to a complicated shape member can be expected.

[Brief description of the drawings]

FIG. 1. Effect of Fe on friction coefficient of aluminum alloy plate
4 is a graph showing the influence of -P plating weight and surface pressure.

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

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

FIG. 4 is a graph showing the influence of the presence or absence of a zincate layer and the basis weight of plating on the plating adhesion of an aluminum alloy plate.

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Yasuji Uesugi 1 Kawasaki-cho, Chiba-shi, Chiba Kawasaki Steel Corporation Research and Development Headquarters (72) Inventor Makoto Imanaka 1 Kawasaki-cho, Chiba-shi, Chiba Kawasaki (72) Inventor Takaaki Hira 1 Kawasaki-cho, Chiba-shi, Chiba Prefecture In-house Technology Research Headquarters, Chiba Pref. (72) Koichi Hashiguchi 1 Kawasaki-cho, Chiba-shi, Chiba Address Kawasaki Steel Corporation Research and Development Headquarters (72) Inventor Motohiro Nambae 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Furukawa Aluminum Industry Co., Ltd. (58) Field surveyed (Int. Cl. ⁶ , DB Name) C23C 30/00

Claims (1)

(57) [Claims] 1. A zincate layer on a surface of an aluminum alloy plate containing at least 4% by weight of Mg and a basis weight of 3-2.
Characterized by having a Fe-based plating layer of 0 g / m ² ,
An aluminum alloy sheet having an elongation of 30% or more, a sliding resistance of 0.13 or less, and a very small dependency of the sliding resistance on surface pressure, which is excellent in both formability and plating adhesion.