JPH05368A - Heat exchanger made of low-temperature brazed aluminum alloy - Google Patents

Abstract

PURPOSE:To allow the formation of the heat exchanger made of an aluminum alloy to be brazed at <=500 deg.C to a lighter weight and smaller size than heretofore and to form this heat exchanger to the strength higher than heretofore. CONSTITUTION:This heat exchanger is constituted by brazing aluminum alloy fin materials contg. 3.0 to 12.0wt.% Fe, 3.0 to 12.0wt.% Fe and <=16wt.% in total one or >=2 kinds of the elements selected from respectively 0.1 to 5.0wt.% V, Cr, Mn, Ni, Ti, Zr, Mo, Co, or W, 3.0 to 12.0wt.% Fe and one or >=2 kinds selected from 0.1 to 2.5wt.% Si, 0.1 to 0.5wt.% Mg, and 0.1 to 1.5wt.% Cu or 3.0 to 12.0wt.% Fe and <=16wt.% in total one or 2 kinds of the elements selected from respectively 0.1 to 5.0wt.% V, Cr, Mn, Ni, Ti, Zr, Mo, Co or W and further one or >=2 kinds of the elements selected from 0.1 to 2.5wt.% Si, 0.1 to 0.5wt.% Mg and 0.1 to 1.5wt.% Cu and consisting of the balance aluminum and passage constituting members at <=500 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy heat exchanger brazed at a temperature of 500 ° C. or lower, and particularly to a heat exchanger for automobiles.

[0002]

2. Description of the Related Art Heat exchangers used in automobiles include radiators, oil coolers, condensers and evaporators,
Most of them are manufactured by a brazing method using Al and Al alloys. Usually, Al-Si type brazing material is used for brazing, so brazing is performed at a high temperature of about 600 ° C. In a heat exchanger such as a radiator, for example, as shown in Fig. 1, thin fins (2) processed into a corrugated shape are integrally formed between a plurality of tubes (1), and
Both ends of (1) are opened in the space composed of the header (3) and the tank (5), respectively, and the hot refrigerant is passed from the space on one tank side through the tube (1) to the space on the other tank side. To heat the tubes (1) and fins (2) to circulate the heat-cooled refrigerant again. In the figure, (4) indicates a side plate.

By the way, in recent years, heat exchangers have been in the direction of weight reduction and downsizing, and therefore thinning of materials has been desired. However, when the conventional material is thinned, the strength of the fin material becomes insufficient because the thickness of the material is reduced, and the pressure resistance of the heat exchanger is reduced. Therefore, some high strength alloys have been proposed, but sufficient strength has not been obtained. This is because there is brazing that heats up to around 600 ° C as the final process of the product, so a mechanism for improving strength such as work hardening cannot be used.

[0004]

In view of the above problems, it is important for the present invention to develop a fin material having high strength after brazing in order to obtain a heat exchanger having improved strength after brazing. Therefore, for this reason, the present invention has been accomplished on the basis that the problem can be solved by using a brazing method in which the brazing temperature is low, instead of the conventional brazing method. Brazing with a low brazing temperature is a brazing method developed in recent years because of a growing demand for a lower brazing temperature due to a reduction in brazing cost. By lowering the brazing temperature, various advantages such as shortening the brazing time, reducing the amount of heat required for brazing, reducing the cost of the brazing furnace, and improving the durability of the brazing furnace are produced. As a brazing filler metal for low temperature brazing currently developed, if the melting point is 500 ° C. or lower, for example, pure Zn, Zn—Al based Zn—28 wt% or lower Al alloy, Zn
There are -Cd type, Sn-Zn type, Sn-Pb type and the like. However, considering the corrosion resistance of the heat exchanger after brazing, Zn
-Al type brazing material is most desirable.

That is, one of the present inventions is that the Fe content is 3.0 to
It is characterized in that it is constituted by brazing an aluminum alloy fin material containing 12.0 wt% and the balance being substantially aluminum, and a passage constituting member at a temperature of 500 ° C. or less.

According to another aspect of the present invention, Fe is added in an amount of 3.0 to 1
Contains 2.0 wt%, V: 0.1-5.0 wt%, Cr: 0.1-5.0
wt%, Mn: 0.1 to 5.0 wt%, Ni 0.1 to 5.0 wt% T
i 0.1 to 5.0 wt%, Zr: 0.1 to 5.0 wt%, Mo: 0.1
~ 5.0 wt%, Co: 0.1 ~ 5.0 wt%, W 0.1 ~ 5.0 wt%
Of the aluminum alloy fin material containing one or more of the above elements in a total amount of 16 wt% or less, and the balance being substantially aluminum, and the passage forming member.
It is characterized by being configured by brazing at a temperature of ℃ or less.

According to another aspect of the present invention, Fe is 3.0 to 1
Contains 2.0 wt%, Si: 0.1-2.5 wt%, Mg: 0.1-
0.5 wt%, Cu: 0.1-1.5 wt%, 1 or 2
An aluminum alloy fin material containing at least one element and the balance being substantially aluminum, and a passage forming member.
It is characterized by being configured by brazing at a temperature of 500 ° C. or less.

According to another aspect of the present invention, Fe is added in an amount of 3.0 to 1
Contains 2.0 wt%, V: 0.1-5.0 wt%, Cr: 0.1-5.0
wt%, Mn: 0.1 to 5.0 wt%, Ni 0.1 to 5.0 wt% T
i 0.1 to 5.0 wt%, Zr: 0.1 to 5.0 wt%, Mo: 0.1
~ 5.0 wt%, Co: 0.1 ~ 5.0 wt%, W: 0.1 ~ 5.0 wt%
%, One or more elements are contained in a total amount of 16 wt% or less, and Si: 0.1 to 2.5 wt%, M
g: 0.1 to 0.5 wt%, Cu: 0.1 to 1.5 wt% from 1
One or two or more elements are contained, and an aluminum alloy fin material whose balance consists essentially of aluminum and the passage constituting member are brazed at a temperature of 500 ° C or less. is there.

[0009]

First, the alloy composition of the fin material according to the present invention will be described. The first invention uses an aluminum alloy fin material containing 3.0 to 12.0 wt% Fe and the balance being substantially aluminum. Fe exists as dispersed particles and solid solution Fe in the alloy and prevents the fin from softening due to recrystallization of the fin material during brazing heating at 500 ° C. or less. That is, the dispersed particles make the sub-crystal grains fine and stable, and the solid solution Fe pins dislocations. However, if Fe is less than 3.0 wt%, the above-mentioned action is insufficient, and if added in excess of 12.0 wt%, the formability of the material is deteriorated and the corrugation as a fin material cannot be performed. Therefore, the Fe content is set to 3.0 to 12.0 wt%.

The second invention is a further improvement of the first invention, containing 3.0 to 12.0 wt% of Fe, and V:
0.1-5.0 wt%, Cr: 0.1-5.0 wt%, Mn: 0.1-
5.0 wt%, Ni 0.1-5.0 wt%, Ti: 0.1-5.0 wt
%, Zr: 0.1 to 5.0 wt%, Mo: 0.1 to 5.0 wt%, C
o: A fin material containing 0.1 to 5.0 wt% and W: 0.1 to 5.0 wt% so that the total content is 16 wt% or less, and the balance is substantially aluminum . Here, V, Cr, Mn, Ni, Ti, Zr,
Mo, Co, and W all exist as fine intermetallic compounds, assist the function of Fe, and contribute to the improvement of strength. However, in all cases, if the amount is less than 0.1 wt%, the action is not sufficient, and if added in excess of 5.0 wt%, only coarse particles are produced and the strength is not improved. Therefore, V, Cr, M
The amount of each of n, Ni, Ti, Zr, Mo, Co, and W added is 0.1 to 5.0 wt%. These elements are effective even if only one kind or two or more kinds are added, but the total addition amount is determined to be 16 wt% or less. This is because if the total amount added exceeds 16 wt%, the formability will decrease.

The third invention is a further improvement of the first invention by a mechanism different from that of the second invention.
3.0 to 12.0 wt%, Si: 0.1 to 2.5 wt%, M
g: 0.1 to 0.5 wt%, Cu: 0.1 to 1.5 wt% from 1
A fin material containing one kind or two or more kinds of elements and the balance being substantially aluminum is used. Where Si, M
g and Cu improve the strength in a solid solution state in the alloy, and further improve the strength by the aging effect when the cooling rate during brazing is high. However, in all cases, if the amount is less than 0.1 wt%, the action is not sufficient. When the amount of Si exceeds 2.5 wt%, a coarse intermetallic compound bonded with Fe is generated, which hinders the improvement of strength. When Mg exceeds 0.5 wt%, it reacts with the flux used for brazing, and brazing cannot be performed. When Cu exceeds 1.5 wt%, the fin potential becomes noble and corrosion progresses from the tube when used as a heat exchanger. Therefore, the addition amount of each is
Si: 0.1 to 2.5 wt%, Mg: 0.1 to 0.5 wt%, Cu:
Set to 0.1 to 1.5 wt%. It should be noted that these elements are effective even if only one kind or two or more kinds are added.

The fourth invention is the second invention from the first invention.
Fe is a combination of the third and third inventions.
3.0 to 12.0 wt%, V: 0.1 to 5.0 wt%, Cr: 0.1
~ 5.0 wt%, Mn: 0.1 ~ 5.0 wt%, Ni: 0.1 ~ 5.0
wt%, Ti: 0.1 to 5.0 wt%, Zr: 0.1 to 5.0 wt%,
Mo: 0.1-5.0 wt%, Co: 0.1-5.0 wt%, W:
It contains one or more elements from 0.1 to 5.0 wt% so that the total amount is 16 wt% or less, and Si: 0.1 to 5.0
2.5 wt%, Mg: 0.1-0.5 wt%, Cu: 0.1-1.5 wt
%, A fin material containing one or two or more elements out of 10% and the balance being substantially aluminum. The role of the additive element of the fin material is the same as above.

The alloy components of the fin material according to the present invention have been described above.
If it is less than 0.1 wt% and less than 1.0 wt% in total, it will not impair the present invention even if it is contained as an unavoidable impurity or is added for the purpose of refining the ingot structure.

In the case of assembling a heat exchanger using the aluminum alloy fin material, it is easiest to use it in combination with a passage forming member coated with a low melting point brazing material. In this case, brazing is usually performed by a method such as thermal spraying, hot dipping, electroplating, vapor deposition, or pressure bonding. Further, when corrosion resistance is required inside, it is particularly recommended that a sacrificial layer is provided inside the passage constituting member to form a three-layer material to enhance the anticorrosion effect. The fin material according to the present invention has a plate thickness of 120 μm or less.

[0015]

EXAMPLES The present invention will be described in more detail based on examples. The fin material having the alloy composition shown in Table 1 was combined with the following tube material and header material to assemble the radiator shown in FIG. JIS A 3003 alloy (Al-0.15 wt% Cu-1.
1 wt% Mn) as the core material, Zn-15 wt% Al alloy on the outside 10% of the total plate thickness, and JIS A 7072 alloy (Al-1 wt% on the inside
Zn) is also clad with 10% of the total plate thickness, and an electric resistance welded tube (1) with a thickness of 0.3 mm, a corrugated fin (2) with a thickness of 0.1 mm for each of the above components, and Zn-15 wt% Al alloy is 8% of the total thickness, and 7072 alloy is used on the back surface for the same thickness of 10%.
1.6 mm thick header plate clad with 3% (3)
And a Zn-15 wt% Al alloy on one side of the 3003 alloy for all plate thicknesses.
A side plate (4) having a thickness of 1.2 mm and clad with 10% was assembled as shown in FIG. 2 to form a radiator core, which was fixed with a jig.

[0016]

[Table 1]

The assembly was degreased with an organic solvent and placed on a stainless steel tray. And AlF ₃ and CsF
Is applied to the joint with a basic composition of 10% fluoride flux, and the tray is inserted into an electric furnace in a nitrogen gas atmosphere with a dew point of -40 ° C and a temperature of 420 ° C, and heated for 5 minutes. Brazing was carried out. At the same time, the fin material was heated to measure the tensile strength of the fin material after heating by brazing.
After the brazing and heating, the radiator was taken out of the furnace and the brazing condition was investigated and shown in Table 2. Also, by checking the number of repetitions until the tube ruptures and the radiator is deformed by applying or unloading ² kgf / cm ² of water pressure inside the electric resistance welded tube of the radiator, Table 2 is shown as an index of the pressure resistance of the radiator. It was However, as a guideline, repeat 100,000 times,
So the experiment was stopped. As a conventional example, the core material is JIS
A 3003 alloy and JIS A 7072 alloy and JIS A 4343 alloy (Al
-7.5 wt% Si) was assembled by hot-pressing brazing sheet of the same structure, and a similar radiator was assembled.
10% of fluoride-based flux based on F ₃ and KF
The concentrate was applied and brazed at a temperature of 600 ° C. in the same furnace as above.

[0018]

[Table 2]

As is clear from Table 2, the radiator according to the present invention has a good brazing condition, and the tensile strength of the fin material after heating by brazing is shown in Table 2. The present invention is compared with the conventional material. And the strength has improved. Moreover, the pressure resistance is also superior to the conventional material.

[0020]

EFFECTS OF THE INVENTION According to the present invention, a heat exchanger that is lighter and smaller than conventional ones and has higher strength than the conventional ones is produced, and a remarkable industrial effect is achieved.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of an automobile radiator.

[Explanation of symbols]

1 tube 2 corrugated fins 3 header plate 4 side plates 5 plastic tanks

Claims (4)

[Claims] 1. An aluminum alloy fin material containing 3.0 to 12.0 wt% of Fe, the balance being substantially aluminum, and a passage forming member are brazed at a temperature of 500 ° C. or less. Low temperature brazed aluminum alloy heat exchanger. 2. Fe: 3.0 to 12.0 wt%, V: 0.1
~ 5.0 wt%, Cr: 0.1 ~ 5.0 wt%, Mn: 0.1 ~ 5.0 w
t%, Ni: 0.1 to 5.0 wt%, Ti: 0.1 to 5.0 wt%,
Zr: 0.1-5.0 wt%, Mo: 0.1-5.0 wt%, Co:
0.1 to 5.0 wt%, W: An aluminum alloy fin material containing one or more elements from 0.1 to 5.0 wt% so that the total is 16 wt% or less, and the balance is substantially aluminum. A low-temperature brazed aluminum alloy heat exchanger, characterized by being brazed to a passage constituent member at a temperature of 500 ° C or less. 3. Fe containing 3.0 to 12.0 wt% and Si:
0.1-2.5 wt%, Mg: 0.1-0.5 wt%, Cu: 0.1-
Contains one or more elements from 1.5 wt%,
A low-temperature brazed aluminum alloy heat exchanger, which is constituted by brazing an aluminum alloy fin material, the balance of which is substantially aluminum, and a passage forming member at a temperature of 500 ° C. or less. 4. Fe of 3.0 to 12.0 wt% and V: 0.1
~ 5.0 wt%, Cr: 0.1 ~ 5.0 wt%, Mn: 0.1 ~ 5.0 w
t%, Ni: 0.1 to 5.0 wt%, Ti: 0.1 to 5.0 wt%,
Zr: 0.1-5.0 wt%, Mo: 0.1-5.0 wt%, Co:
0.1 to 5.0 wt%, W: 0.1 to 5.0 wt%, one or more elements are contained so that the total amount is 16 wt% or less, and Si: 0.1 to 2.5 wt%, Mg: 0.1 to 0.5 wt
%, Cu: An aluminum alloy fin material containing one or more elements from 0.1 to 1.5 wt% and the balance substantially consisting of aluminum, and a passage forming member at 500 ° C.
A low-temperature brazed aluminum alloy heat exchanger, characterized by being brazed at the following temperatures.