JP2000319740A - Aluminum alloy material with excellent adhesive characteristics - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an aluminum alloy material whose mechanical strength is larger than that of an existing material 6063 alloy, having an approvable strength of adhesion after a corrosion test and excellent moldability and chemical treatability. SOLUTION: This is an aluminum alloy which consists of >2.6 wt.% to <=5.0 wt.% Si, >0.3 wt.% to <=2.0 wt.% Fe >0.3 wt.% to <=2.0 wt.% Cu, >0.1 wt.% to <=1.5 wt.% Mn, >0.1 wt.% to <=1.0 wt.% Mg, >0.2 wt.% to <=1.0 wt.% Zn, and the balance Al with inevitable impurities and the roughness of at least one surface of which is not smaller than 2 μm at Ra and not smaller than 20 μm at Rmax.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy material having excellent adhesiveness and a method for producing the same, and more particularly to an aluminum alloy extruded material used as a frame material for automobiles.

[0002]

2. Description of the Related Art In the automobile industry, there is a strong demand for reduction of vehicle body weight for the purpose of improving fuel efficiency and performance, and the specific gravity of iron or steel material has been replaced by iron or steel material used as a conventional structural member. There is growing demand for almost one third of aluminum materials (particularly aluminum alloys). In addition, aluminum alloys are not only lightweight, but also have excellent corrosion resistance, workability, surface treatment properties, etc., and are easy to recycle, so they have received the most attention as structural members for automobiles. , Bumpers, heat exchangers, engines, etc., and the range of application to other parts is increasing. By the way, when such an aluminum alloy is used for an automobile structural member, the manufacturing process is basically the same as that of a conventional iron-based material, and in principle, formability, weldability, corrosion resistance after painting, aesthetics and It is required to be comparable in terms of adhesiveness and the like. In the case of aluminum alloy, normal casting, soaking, hot rolling, cold rolling,
After finishing annealing (may be performed during cold rolling), forming (cutting to a predetermined size from a coil or a sheet material cut to a predetermined size from a coil), joining (joining to peripheral members by bonding and welding), Pre-coating treatment, then coating (undercoating (electrodeposition coating), intermediate coating, topcoating), and finally in the order of cladding.

[0003]

However, when an aluminum alloy material is used as it is for a structural member for an automobile, the initial bonding strength does not reach a desired level, or a corrosion durability test is performed in a severe environment. When,
There has been a problem that the bonding strength of the bonding portion falls below a desired level due to peeling off from the bonding portion and the safety and reliability are hindered.

[0004] Considering the cause of the poor adhesion of the aluminum alloy material from the surface properties of the aluminum alloy, if the surface oxide film of the aluminum alloy is thick, the surface oxide film itself acts as a fragile layer (peeled portion), which lowers the adhesive strength. It has been known that this is
In No. 1, the thickness of the surface oxide film is 10 to 200 °, the surface roughness is 0.1 to 2.5 μm in Ra, and 0.5 to
It is specified as 40 μm. In other words, in order to obtain adhesiveness, it has been known to control the thickness of the surface oxide film.
To control the surface oxide film, alkali etching or the like is required, and it is difficult to control the oxide film thickness on the surface in a stable manner due to variations in the chemical reaction of the solution. There is a problem that the variation in the above results in unstable adhesion.

[0005]

In order to solve the above-mentioned problems, the present invention provides (1) over 2.6 wt% to 5.0 wt%.
Si below, F above 0.3 wt% and below 2.0 wt%
e, Cu exceeding 0.3 wt% and 2.0 wt% or less;
Mn of more than 1 wt% and not more than 1.5 wt%, 0.1 wt%
, An aluminum alloy containing more than 1.0 wt% Mg, more than 0.2 wt% and less than 1.0 wt% Zn, the balance being aluminum and unavoidable impurities, and at least one surface having a surface roughness of Ra. 2 μm or more, R
(2) an aluminum alloy material excellent in adhesiveness characterized by having a maximum of 20 μm or more; and (2) the surface of the alloy material according to (1) having a surface roughness Ra of 2 μm or more and an Rmax of 20 μm or more. (3) An aluminum alloy material described in (2) above, which is a joint member, and (4) A structural member for automobiles (2) )), And (5) more than 2.6 wt% to 5.0.
wt% or less Si, more than 0.3 wt% and less than 2.0 wt% Fe, more than 0.3 wt% and less than 2.0 wt% C
u, Mn exceeding 0.1 wt% and 1.5 wt% or less.
Mg of more than 1 wt% and less than 1.0 wt%, 0.2 wt%
And an aluminum alloy containing 1.0 wt% or less of Zn and the balance of aluminum and unavoidable impurities, wherein at least one surface has a surface roughness of 2 μm or more in Ra and 20 μm or more in Rmax. Surface roughness Ra of aluminum alloy material with excellent adhesiveness is 2μ
The present invention provides a method for producing an aluminum alloy material, characterized in that surfaces having Rmax of 20 μm or more are fixed with an adhesive, and has stable adhesion without controlling an oxide film. It is. In addition, the aluminum alloy material according to any one of the above items (1) to (5) only needs to have the specified surface roughness on at least one surface, and both surfaces may satisfy the surface roughness.

[0006]

The reasons for limiting the components of the present invention will be described. Si is dissolved in aluminum alloy or elemental S
It has the effect of increasing the strength of the alloy by precipitating Mg ₂ Si in the presence of i and Mg and the effect of increasing the deformation resistance of the material. Further, the ternary eutectic of Si, Mg ₂ Si, and Mg has an effect of welding to the die and increasing the roughness. 2.6wt% Si
%, The effect is small, and if Si exceeds 5.0 wt%, the deformation resistance of the material becomes too large to make extrusion difficult. Therefore, in the present invention, the amount of Si is set to 3.
The content of Si was defined to be more than 0 wt% and 5.0 wt% or less. F
e is a solid solution in an aluminum alloy or Al ₃ Fe and S
i, has the effect of precipitating Al and the Al-Si-Fe-based compound to increase the material strength. If the Fe content is less than 0.3 wt%, the effect of the material strength is poor, and if it exceeds 2.0 wt%, the corrosion resistance of the material is impaired and the adhesion is impaired. Therefore, in the present invention, the amount of Fe exceeds 0.3 wt% and exceeds 1.5 wt%.
wt% or less.

[0007] Cu has the effect of increasing the strength by forming a solid solution in the matrix and has the effect of improving the material formability. If the Cu content is 0.5 wt% or less, the effect of the material strength is small, and if it exceeds 2.0 wt%, the strength is improved, but the deformation resistance at the time of extrusion becomes large, and the extrusion cannot be performed. In addition, the corrosion resistance of the material is impaired and the adhesion is impaired. Therefore, in the present invention, the amount of Cu is 0.5w
It is specified that the content exceeds t% and is 2.0 wt% or less. Mn is Fe,
Mn has the effect of forming an intermetallic compound with Si and contributing to the improvement of strength, and has the effect of increasing the deformation resistance of the material.
If the amount is less than 0.1 wt%, the effect of improving strength is small,
If the content exceeds 1.5 wt%, not only the resistance at the time of extrusion becomes large and it is impossible to extrude, but also the surface is roughened to cause a problem in the surface appearance. Therefore, in the present invention, the amount of added Mn is specified to be more than 0.1 wt% and not more than 1.5 wt%.

[0008] Mg forms an intermetallic compound with Si and contributes to improvement in strength. If the amount of Mg is less than 0.1 wt%, the effect of improving strength is small, and if it exceeds 0.5 wt%, Mg ₂
Although a large amount of Si precipitates to improve the strength, coarse precipitates serve as starting points of cracks during extrusion. Therefore, in the present invention, the amount of added Mg is specified to be more than 0.1 wt% and 0.5 wt% or less. Zn forms an intermetallic compound with Mg and contributes to the improvement of strength, and also has the effect of increasing the frictional resistance of the die surface during extrusion. It was found that when the frictional resistance of the die surface was increased, the surface roughness of the extruded material had the range of the present invention. If the Zn content is less than 0.2 wt%, the effect of improving strength and the roughness of the die surface do not fall within the scope of the present invention, and if it exceeds 1.0 wt%, the corrosion resistance of the material is deteriorated, and the adhesive strength is reduced. Therefore, in the present invention, the Zn content is specified to be more than 0.2 wt% and 1.0 wt% or less.

In the present invention, the amounts of Cr and Ti are not particularly specified. However, there is no problem if Cr is less than 0.1 wt% so as not to inhibit the quenching sensitivity. 0.1 wt% or less, B is 0.02 wt%
The following is added, but there is no problem in various adhesive properties. In the present invention, the definition of the surface roughness is an important condition. In the present invention, the surface roughness is 2 μm or more in Ra, Rmax
Is defined as 20 μm or more because the surface roughness Ra is 2 μm.
When it is less than μm, the contact area between the aluminum surface and the adhesive becomes small, so that a desired adhesive strength cannot be obtained at the initial stage of the adhesion and after the corrosion test, and Rmax is 20 μm.
If it is less than m, the effect on the adhesive strength of the oxide film on aluminum becomes large, and as a result, the thickness of the oxide film on aluminum due to uneven etching depends on the initial and after the corrosion test the adhesive strength. In addition, the desired adhesive strength cannot be stably obtained. In the present invention, a joint refers to one used for the purpose of ensuring good adhesion to a member to be adhered, and specifically, a lap joint type is mainly used, but a mount member for a flat plate is used. It is used in the form of a joint to be fixed or an insertion joint or the like in which extruded profiles having different dimensions are used and both are inserted and combined. Further, as the structural members for automobiles defined by the present invention, there are those mentioned in the above-mentioned "Prior Art", and preferred are a frame, a body panel, an inner panel and the like. The adhesive used in the present invention is used for joint members, structural members for automobiles, and the like,
Known ones are appropriately selected depending on the conditions. For example, thermosetting resin adhesives (epoxy resin, phenol resin,
Resorcinol resin) is preferably used, but is not limited thereto.

[0010]

The present invention will be described below in detail with reference to the following examples. (1) Aluminum material A billet having an alloy composition shown in Table 1 was produced by a semi-continuous casting method, homogenized at a temperature of 490 ° C for 4 hours, and air-cooled after the homogenization. Then, it was heated to a temperature of 400 ° C. and hot-extruded into a 2 mm shape with a flat plate. Thereafter, an aging precipitation treatment was performed at a temperature of 180 ° C. for 2 hours to prepare a test piece. Table 1 shows the results of measuring the surface roughness of the obtained test pieces.

(2) Surface treatment Using a methylene chloride solution, oil and deposits on the surface were removed. In addition, a test piece in which the surface hydroxide was removed with 30% nitric acid after partially etching the surface with a 5% NaOH solution was also prepared.

(3) Preparation of heat-curable epoxy resin adhesive Commercially available adhesive (epoxy adhesive manufactured by Sunstar Giken; E
-6208) to the same adhesive and aluminum material (dimensions: 25 mm in width, 100 mm in length) and other aluminum materials of the same dimensions using the above adhesive (thickness of the adhesive: 0.1 mm). 1mm clip), wrap width 13
mm, and heat-cured at 190 ° C. for 30 minutes to prepare an adhesion test piece (n = 3). Then JIS
The salt spray test of Z2371 was performed for 90 days, the tensile shear strength before and after the corrosion test was measured, and the residual ratio (%) of the strength was calculated by the following formula.

Residual strength (%) = (shear strength after corrosion test) / (shear strength before corrosion test) × 100 The results are shown in Table 1.

[0014]

[Table 1]

[0015] As shown in Table 1, the samples of the present invention had a high strength retention rate in the corrosion test even without surface treatment.
It has been confirmed that an aluminum material without surface treatment has a surface oxide film having a thickness of about 100 °). On the other hand, Si in Comparative Example 1, Cu in Comparative Example 5, and M in Comparative Example 9
Extrusion was not possible because g exceeded the example of the present invention.
Comparative Example 2 contained Si, Comparative Example 4 contained Fe, Comparative Example 12
Since Zn was lower than that of the examples of the present invention, the surface roughness was lower than that of the examples of the present invention, and the residual strength ratio after the corrosion test was significantly lower than that of the examples of the present invention. Since Fe in Comparative Example 3 and Zn in Comparative Example 11 are higher than those of the present invention, the initial surface roughness is higher than that of the present invention, but the corrosion resistance after the corrosion test is deteriorated, and the adhesive strength after the corrosion test is low. It was significantly lower than that of the examples of the present invention. Comparative Example 6
In Comparative Example 8, Mn in Comparative Example 8, and Mg in Comparative Example 10.
However, the adhesive strength after the corrosion test was the present invention because it was lower than that of the present invention, but the strength was significantly lower than that of the present invention. In Comparative Example 7, since Mn was greater than that of the present invention, the extruded surface was scratched, resulting in a defective product.

[0016]

As described above, the aluminum alloy material of the present invention has higher mechanical strength than the conventional 6063 alloy, has a desired adhesive strength even after the corrosion test, and has good formability and chemical conversion. It has excellent processability and has an industrially significant effect.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoichiro Totsugi 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Inside Furukawa Electric Co., Ltd. (72) Inventor Noboru Hayashi 1-4-1 Chuo, Wako-shi, Saitama Honda R & D Co., Ltd.

Claims (5)

[Claims] 1. Si exceeding 2.6 wt% and 5.0 wt% or less, Fe exceeding 0.3 wt% and 2.0 wt% or less,
More than 0.3 wt% and less than 2.0 wt% Cu, 0.1w
Mn in excess of t% and 1.5 wt% or less, Mg in excess of 0.1 wt% and 1.0 wt% or less, and Mg in excess of 0.2 wt% and 1.0 wt%
an aluminum alloy containing at most Zn by weight and the balance of aluminum and unavoidable impurities, at least one surface having a surface roughness of 2 μm or more in Ra, Rmax
An aluminum alloy material having excellent adhesiveness, having a thickness of 20 μm or more. 2. The aluminum alloy material according to claim 1, wherein surfaces of the alloy material according to claim 1 having a surface roughness Ra of 2 μm or more and a Rmax of 20 μm or more are fixed with an adhesive. 3. The aluminum alloy material according to claim 2, which is a joint member. 4. The aluminum alloy material according to claim 2, which is a structural member for an automobile. 5. An alloy containing more than 2.6 wt% and not more than 5.0 wt% of Si, more than 0.3 wt% and not more than 2.0 wt% of Fe,
More than 0.3 wt% and less than 2.0 wt% Cu, 0.1w
Mn in excess of t% and 1.5 wt% or less, Mg in excess of 0.1 wt% and 1.0 wt% or less, and Mg in excess of 0.2 wt% and 1.0 wt%
an aluminum alloy containing at most Zn by weight and the balance of aluminum and unavoidable impurities, at least one surface having a surface roughness of 2 μm or more in Ra, Rmax
The surface roughness Ra of the aluminum alloy material excellent in adhesiveness, which is 20 μm or more, is 2 μm or more, Rm
A method for manufacturing an aluminum alloy material, wherein surfaces having ax of 20 μm or more are fixed with an adhesive.