JP2000087171A - Aluminum alloy composite material excellent in bending fatigue characteristic and corrosion resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aluminum alloy composite material excellent in bending fatigue characteristics, corrosion resistance and strength and suitable for the radiator and heater core of an automotive heat exchanger. SOLUTION: This material is the one in which an Al alloy contg., by weight, 0.15 to 0.8% Si, 0.1 to 0.5% Fe, 0.8 to 1.6% Mn, 0.2 to 0.8% Cu, and the balance Al with inevitable impurities is used as a core, and one side of the core is clad with a sacrificial anode material contg. 1 to 10% Zn, Cu in the range of ±30% of the content of Cu in the core, and the balance Al with inevitable impurities.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy composite material having excellent bending fatigue characteristics, corrosion resistance and strength suitable for a radiator and a heater core of a heat exchanger for an automobile.

[0002]

2. Description of the Related Art For example, as shown in FIG. 1, a radiator of a heat exchanger for an automobile is provided with a tube 1 for flowing a coolant, a corrugated fin 2 and a header plate 3, and the assembled body is heated to 600.degree. Manufactured by brazing at ambient temperatures. In FIG. 1, reference numeral 4 denotes a tank for collecting and delivering a refrigerant. The tube 1 is clad with a brazing material (Al-Si based alloy: JIS 4045 alloy, etc.) on one side (atmosphere side) of a core material (Al-Mn based alloy: JIS 3003 alloy, etc.), and the other side (refrigerant side). Used is an aluminum alloy composite material clad with a sacrificial anode material (Al-Zn-based alloy: JIS7072 alloy, etc.).
An l-Mn alloy (such as JIS3003 alloy) is used, and the same composite material as the tube 1 is used for the header plate 3.

[0003]

By the way, since a coolant for cooling the engine is circulated and pumped into the radiator by a pump, the inside of the radiator becomes high pressure by the coolant when the pump is operating, and the tube is cooled. Receives a force in a direction in which the cross-sectional shape expands, and the header plate receives a force in a direction in which a caulked joint between the header plate and the resin tank that is caulked is opened, and a tensile stress acts on the sacrificial anode material. If such a state is repeated for a long period of time, the tube or the header plate may be broken by fatigue, and there is a problem in terms of life and reliability.

[0004] The fatigue fracture occurs when a microcrack is first formed on the surface and the crack advances inside. For this reason, measures have been taken to suppress the occurrence of microcracks by increasing the strength of the sacrificial anode material on the surface where the maximum stress is applied.
The IS7072 alloy (Al-Zn-based alloy) by adding Mg to precipitate Mg ₂ Si method of increasing the hardness of the sacrificial anode material surface has been proposed (Japanese Patent Laid-Open No. 8-68280). However, the above method has a problem that grain boundary destruction easily occurs in the sacrificial anode material. In addition, it is desired to reduce the thickness of materials used for the purpose of reducing the weight and cost of automobiles, and accordingly, there is a strong demand for the development of high strength and high corrosion resistant materials. In order to improve the strength of the radiator material, there is an effect that the rigidity of the radiator itself is increased and deformation due to refrigerant pressure can be reduced. The present invention provides bending fatigue properties, corrosion resistance, and the like suitable for a radiator, a heater core, and the like of a heat exchanger for an automobile.
And an aluminum alloy composite material having excellent strength.

[0005]

According to the first aspect of the present invention,
0.15 to 0.8 wt% of Si, 0.1 to 0.5 wt% of Fe
%, Mn 0.8 to 1.6 wt%, Cu 0.2 to 0.8
wt.%, and an Al alloy consisting of the balance of Al and inevitable impurities is used as a core material.
aluminum having excellent bending fatigue characteristics and corrosion resistance, characterized in that u is contained within the range of ± 30% of the amount of Cu contained in the core material, and a sacrificial anode material comprising the balance of Al and unavoidable impurities is clad. Alloy composite material.

According to a second aspect of the present invention, the Si content is 0.15 to 0.15.
0.8 wt%, Fe: 0.1-0.5 wt%, Mn: 0.8
~ 1.6wt%, contains 0.2 ~ 0.8wt% of Cu, and further contains one or more of Cr, Zr and Ti at 0.3wt each.
% Or less, and an Al alloy consisting of the balance of Al and unavoidable impurities is used as a core material.
Aluminum having excellent bending fatigue characteristics and corrosion resistance, characterized in that Cu is contained within a range of ± 30% of the amount of Cu contained in the core material, and a sacrificial anode material comprising the remaining Al and unavoidable impurities is clad. Alloy composite material.

According to a third aspect of the present invention, the Si content is 0.15 to 0.15.
0.8 wt%, Fe: 0.1-0.5 wt%, Mn: 0.8
芯 1.6 wt%, Cu is 0.2〜0.8 wt%, Al alloy consisting of the remaining Al and unavoidable impurities is used as a core material, and Zn is 1-10 wt% and Cu is a core material on one surface of the core material. Contained within a range of ± 30% of the amount of Cu contained therein,
0.002-0.3wt%, Sn 0.002-0.3wt%
An aluminum alloy composite material having excellent bending fatigue characteristics and corrosion resistance, characterized in that one or two of the above are contained and a sacrificial anode material comprising the balance of Al and inevitable impurities is clad.

According to a fourth aspect of the present invention, the Si content is 0.15 to 0.15.
0.8 wt%, Fe: 0.1-0.5 wt%, Mn: 0.8
~ 1.6wt%, contains 0.2 ~ 0.8wt% of Cu, and further contains one or more of Cr, Zr and Ti at 0.3wt each.
% Or less, and an Al alloy consisting of the balance of Al and unavoidable impurities is used as a core material.
Cu is contained within a range of ± 30% of the amount of Cu contained in the core material.
One or two kinds of Al-Al-Al-Al-Al-O-Al
And an aluminum alloy composite material having excellent bending fatigue characteristics and corrosion resistance, characterized by being clad with a sacrificial anode material comprising unavoidable impurities.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The alloy composition of the core material of the composite material of the present invention will be described below. Fe and Mn react with each other to form an intermetallic compound, thereby contributing to an improvement in strength. The content of each of these elements is 0.1 to 0.5 wt% or 0.1 wt%, respectively.
The reason why the content is specified in the range of 8 to 1.6 wt% is that even if any of them is less than the lower limit, the effect is not sufficiently obtained. This is because the recrystallized grain size is made small, so that the brazing becomes easy to diffuse in the core material and the brazing property is reduced, and Mn is reduced in the formability and cracks occur during processing.

[0010] Si promotes the precipitation of Mn, increases the intermetallic compound, and further improves the strength. The reason why the content of Si is defined as 0.15 to 0.8 wt% is 0.15 wt%
If the amount is less than 0.8 wt%, the effect is not sufficiently obtained. If the amount exceeds 0.8 wt%, the diffusion of the brazing during heating by brazing increases, and the corrosion resistance of the composite material decreases. The content of Si is 0.3 to
It shows particularly stable characteristics at 0.7 wt%.

Cu exists in a solid solution state in the alloy and contributes to strength improvement. Further, the potential in the core material is made noble to improve the corrosion resistance. The reason that the content is specified in the range of 0.2 to 0.8 wt% is that the effect cannot be sufficiently obtained with 0.2 wt%,
If the content exceeds 0.8 wt%, the Cu-based compound precipitates at the crystal grain boundaries during cooling after brazing and heating, so that intergranular corrosion tends to occur.

Further, if necessary, 0.3 wt.
% Or less of one or more of Cr, Zr, and Ti. These elements form fine intermetallic compounds and improve the strength of the alloy. Each of these elements is 0.3wt%
If it is contained in excess, the moldability decreases and cracks occur during processing.

Next, the alloy composition of the sacrificial anode material of the composite material of the present invention will be described. Zn electrically sacrifices the sacrificial anode material to provide a sacrificial anode effect. Zn content of 1 to 10 wt
The reason for specifying the percentage is that if the content is less than 1% by weight, the effect is not sufficiently obtained, and even if the content exceeds 10% by weight, the effect is saturated and uneconomical.

[0014] Cu contributes to the improvement of the strength of the sacrificial anode material, thereby improving the fatigue resistance. The reason for defining the Cu content within a range of ± 30% of the Cu content contained in the core material is as follows.
If it is more than 0%, the potential difference between the sacrificial anode material and the core material becomes small, so that the sacrificial effect of the sacrificial anode material cannot be sufficiently obtained.
On the other hand, if the content is less than -30 wt%, the strength of the sacrificial anode material cannot be sufficiently obtained, and the effect of improving fatigue resistance cannot be sufficiently obtained.

Furthermore, if necessary, the sacrificial anode material may have I
n 0.002-0.3wt%, Sn 0.002-0.3wt%
% Or one or two of them. These elements improve the self-corrosion resistance of the sacrificial anode material. If the content is less than the lower limit, none of the effects can be sufficiently obtained, and if the content exceeds the upper limit, the processability is lowered.

In the present invention, other elements or unavoidable impurity elements added for the purpose of refining the ingot structure or the like are used as the core material and the sacrificial anode material if their contents are 0.05 wt% or less. There is no problem with either.

The aluminum alloy composite material of the present invention is obtained by cladding the aluminum alloy core material on one surface with the aluminum alloy sacrificial anode material, and optionally cladding the aluminum alloy brazing material on the other surface. You can also. As the brazing material, Al-Si JIS
Ordinary brazing materials such as 4045 alloy, JIS4343 alloy and JIS4004 alloy can be applied. Further, JP-A-7-88
No. 634, Cu and Zn are contained in the brazing material.
A material to which an element such as an element is added can also be used.

[0018]

EXAMPLES Sacrificial anode alloys and core alloys of various compositions shown in Tables 1 to 3, and brazing alloys of JIS 4045 alloy were each melt-cast by a conventional method. And then subjected to facing and hot rolling to obtain a sacrificial anode material plate having a thickness of 7 mm and a thickness of 56 m.
m core material and a 7 mm thick brazing material were obtained. Next, these base plates are stacked in this order and hot-rolled and pressed to obtain a thickness of 3.
A 5 mm three-layered clad material was then cold-rolled to a thickness of 0.3 mm and finally at 280 ° C.
The aluminum alloy composite was manufactured by heat treatment for hr.

Each of the composite materials thus obtained was tested for tensile strength, fatigue strength and corrosion resistance. Each test was performed after subjecting the cut test pieces to heat treatment at 600 ° C. for 3 minutes (brazing conditions) in nitrogen gas. Table 4 shows the results. The test method is as follows. Tensile strength: Cut out JIS No. 5 tensile test piece JISZ2
A tensile test was performed in accordance with No. 201. Fatigue strength: A repeated bending fatigue test was performed at a constant strain, oscillating (θ = 20 °), and a frequency of 15 Hz so that a tensile load was applied to the surface of the sacrificial anode material. Corrosion resistance: The test piece was immersed in a corrosive solution with the brazing material side and edges masked, and a heat cycle of 8 hours at 88 ° C. and 16 hours at room temperature was repeated for 6 months, and the depth of pitting corrosion generated after the test. Was measured and determined by the depth of focus method using an optical microscope. Table 4 shows the maximum pit depth. A for the etchant
STM artificial water _{^{(Cl 1- 100ppm, SO 4 2-}} 100p
pm, with CO ₃ ^2- 100ppm).

[0020]

[Table 1] (Note) Brazing material: JIS4045 alloy. * ±% of Cu content in core material.

[0021]

[Table 2] (Note) Brazing material: JIS4045 alloy. * ±% of Cu content in core material.

[0022]

[Table 3] (Note) * Conventional example. * ±% of Cu content in core material.

[0023]

[Table 4]

As is clear from Table 4, No. 1 of the present invention example
-16 had high tensile strength and fatigue strength, and the maximum pit depth was shallow. On the other hand, in Comparative Example No. 17, both the tensile strength and the fatigue strength were low due to the small amount of Cu in the sacrificial anode material, and the through-hole was not formed due to the small amount of Zn, and the sacrificial effect was not sufficiently obtained. No. 18 had a through hole due to the large amount of Si in the core material. In No. 19, tensile strength and fatigue strength were reduced due to a small amount of Cu in the sacrificial anode material. In No. 20, since the core material contained a large amount of Fe, the brazing diffusion during brazing was large, and the corrosion resistance was poor, and through holes were formed. In No. 21, the tensile strength and fatigue strength were reduced due to the small amount of Cu in the core material. In No. 22, cracks occurred during rolling because of a large amount of Zn in the sacrificial anode material. In No. 23, the core material and the sacrificial anode material contained a large amount of Cu, and thus melted during the heating with the addition of brazing. In No. 24, the amount of Zn in the sacrificial anode material was small, so the sacrificial effect was not sufficient, and a through hole was formed. In No. 25, a large amount of Cu was used as the sacrificial anode material, and the potential relationship with the core material was reversed, and a through hole was formed. In No. 26 of the conventional material, tensile strength and fatigue strength decreased because Cu was not contained in the sacrificial anode material.

[0025]

As described above, the aluminum alloy composite of the present invention has a suitable amount of Cu contained in the sacrificial anode material.
By such actions, bending fatigue characteristics, corrosion resistance, and strength are improved, and when used for a radiator of a heat exchanger, the life and reliability thereof are improved, and industrially remarkable effects are exhibited.

[Brief description of the drawings]

FIG. 1 is a partially sectional perspective view showing a radiator.

[Explanation of symbols]

 1 Tube 2 Fin 3 Header plate 4 Tank

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 4F100 AB02A AB10A AB11A AB12A AB13A AB14A AB17A AB17B AB18B AB19A AB21B AB31A AB31B AB40B BA02 EC01 GB51 JB02 JK01 JK04 JL00 YY00A YY00B

Claims (4)

[Claims] 1. 0.15 to 0.8 wt% of Si, 0.1 to 0.5 wt% of Fe, 0.8 to 1.6 wt% of Mn, Cu
And 0.2 to 0.8 wt% of Al, the balance being Al alloy consisting of Al and unavoidable impurities as a core material, 1 to 10 wt% of Zn on one surface of the core material, and amount of Cu contained in the core material of Cu ± 3
An aluminum alloy composite material having excellent bending fatigue characteristics and corrosion resistance, characterized in that it is contained within a range of 0% and is clad with a sacrificial anode material composed of the balance of Al and inevitable impurities. 2. 0.15 to 0.8 wt% of Si, 0.1 to 0.5 wt% of Fe, 0.8 to 1.6 wt% of Mn, Cu
0.2 to 0.8 wt%, and further contains one or more of Cr, Zr, and Ti in an amount of 0.3 wt% or less, and an Al alloy containing the balance of Al and inevitable impurities as a core material, One side of the core material is clad with a sacrificial anode material containing Zn in an amount of 1 to 10% by weight and Cu in a range of ± 30% of the amount of Cu contained in the core material, and the balance being Al and unavoidable impurities. An aluminum alloy composite material having excellent bending fatigue characteristics and corrosion resistance. 3. Si is 0.15 to 0.8 wt%, Fe is 0.1 to 0.5 wt%, Mn is 0.8 to 1.6 wt%, Cu
And 0.2 to 0.8 wt% of Al, the balance being Al alloy consisting of Al and unavoidable impurities as a core material, 1 to 10 wt% of Zn on one surface of the core material, and amount of Cu contained in the core material of Cu ± 3
0% in the range, In 0.002-0.3wt%
% Or one of Sn 0.002 to 0.3 wt% or 2
Aluminum alloy composite material having excellent bending fatigue characteristics and corrosion resistance, characterized by being clad with a sacrificial anode material containing seeds and the balance of Al and unavoidable impurities 4. 0.15 to 0.8 wt% of Si, 0.1 to 0.5 wt% of Fe, 0.8 to 1.6 wt% of Mn, Cu
0.2 to 0.8 wt%, and further contains one or more of Cr, Zr, and Ti in an amount of 0.3 wt% or less, and an Al alloy containing the balance of Al and inevitable impurities as a core material, One side of the core material contains 1 to 10% by weight of Zn and Cu in a range of ± 30% of the amount of Cu contained in the core material.
0.002-0.3wt%, Sn 0.002-0.3wt%
An aluminum alloy composite material having excellent bending fatigue properties and corrosion resistance, characterized in that it is clad with a sacrificial anode material comprising the balance of Al and inevitable impurities.