JPH03180268A - Aluminum alloy-made heat exchanger - Google Patents

Abstract

PURPOSE:To improve brazing ability and pressure resistant strength by using Al material containing the specific % of alloy element to core material for gas phase brazing heat exchanger, which the core material and fin material are made of Al alloy and outer shell is made of Al-Si series alloy clad tube material. CONSTITUTION:In the heat exchanger combining the core material made of Al alloy, the tube material cladding Al-Si series alloy cladded material as the outer shell and the fin material made of Al alloy and constituted by the gas phase brazing, as the core material, the Al alloy composing of 0.6-2.5wt.% Mg, <=1.0wt.% Si, <=1.2wt.% Fe and the balance of Al with inevitable impurities, is used. By this method, the brazing ability and the pressure resistant strength can be improved and therefore, the heat exchange can be lightened with thinning of the tube.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an aluminum alloy heat exchanger,
Increases pressure resistance, reduces weight, and reduces brazing
This is an improved version of .

[Prior art and problems to be solved by the invention] An aluminum alloy tube in which a fin made of Al or Al alloy is joined to a tube made of Al or Al alloy using an Al-8), or Zn-Al alloy brazing filler metal. Heat exchangers are used in automobiles and other equipment because of their light weight and good thermal conductivity.

In recent years, there has been an increasing demand for aluminum alloy heat exchangers to be smaller and lighter, and efforts are being made to increase the strength and reduce the thickness of the members that make up the heat exchanger. However, when the load pressure is increased or the tube material is made thinner,
There were problems such as insufficient pressure resistance and bulging of the tube.

Conventionally, such heat exchangers have been manufactured using the brazing method, and the vacuum brazing method involves placing the assembly to be joined in a vacuum and then heating and brazing it. Although there is a problem in that it is expensive, brazing has the advantage that the surface of the heat exchanger afterwards is clean. However, when attempting to braze a heat exchanger using tube material to which Mg has been added by vacuum brazing, the problem with brazing is that the Mg evaporates during heating, reducing the strength of the tube. There is. Further, there is a problem that a large amount of Mgff1 evaporates, and brazing quickly contaminates the furnace.

The Nokolock brazing method, in which a fluoride-based flux is applied to the assembly and brazed in a furnace, uses a mixture of AlF4 and AlF, which is non-hygroscopic and non-corrosive to aluminum, as the flux. Therefore, brazing has the characteristic that there is no need to remove flux after soldering. When attempting to braze a heat exchanger using tube material to which Mg has been added, the effectiveness of the flux decreases as the fluoride flux and Mg react during brazing. However, there was a problem in that brazing caused defects.

Also, a method has recently been developed in which heat brazing is performed in a non-oxidizing atmosphere in the presence of flux vapor without applying flux to the assembly.

[Means to solve the problem]

In view of this, as a result of various studies, the present invention has found that by using the vapor phase brazing method, heat exchangers using Mg-added tube material can be well brazed, and that Mg of 0.6
The aluminum alloy tube material containing ~2.5wt% (hereinafter wt% is abbreviated as %) has high strength after brazing,
By using this tube, we found that a lightweight heat exchanger with high pressure resistance could be obtained.As a result of further study, we found that we were able to create a heat exchanger that had high pressure resistance, reduced weight, and was made of aluminum with improved brazing properties. Developed an alloy heat exchanger.

That is, the first aspect of the present invention is to combine a tube material made of A4 alloy as the core material and clad with Al-8i or Zn-Al alloy brazing material as the outer skin, and a fin material made of Al or Al alloy, to form a vapor phase brazing material. In the heat exchanger constructed by attaching, the core material is an Al alloy containing 0.6 to 2.5% Mg, 0% SL1 or less, and 1.2% or less Fe, and the balance is Al and inevitable impurities. That is.

The second aspect of the present invention is to use Al alloy as the core material and as the skin material.
- In a heat exchanger constructed by vapor phase brazing, combining a tube material clad with a -3f-based or Zn-All-based alloy brazing material and a fin material made of Al or an Al alloy, the core material contains Mg0.6~ 2.5%, sl 1.0
%, Fe 1.2%, Mn 2.09g or less, and the balance is Ae and unavoidable impurities.

The third aspect of the present invention is that an Al alloy is used as a core material, and an Al alloy is used as a skin material.
- In a heat exchanger constructed by vapor phase brazing, combining a tube material made of Si-based or Zn-Al-based alloy brazing material and a fin material made of Ae or Al alloy, the core material contains Mg0.6 to 2. 5%, sl 1.0% or less,
Fe 1.2%, Cut, [1% below F
The present invention is characterized in that an Al alloy consisting of the remainder Al and unavoidable impurities is used.

The fourth aspect of the present invention is that an Al alloy is used as a core material, and an Al alloy is used as a skin material.
- In a heat exchanger constructed by vapor phase brazing, combining tube material clad with 8i-based or Zn-Al-based alloy brazing material and fin material made of Al or Al alloy, the core material contains Mg0.6 to 2. .5%, SL 1.0% or less,
Contains Fe1.2% or less, Zr0.3% or moreF in history,
The present invention is characterized by using an Al alloy containing one or more of Cr 0.3% or less and N 11.0% or less, with the remainder being Al and inevitable impurities.

The fifth aspect of the present invention is to use Al alloy as the core material and as the skin material.
- In a heat exchanger constructed by vapor phase brazing, combining a tube material clad with Si-based or Zn-Al-based alloy brazing material and a fin material made of Al or Al alloy,
Core material: Mg0.6-2.5%, S, 1.0% or less, Fe
1.2%, Mn 2.0% or less, Cut 0% or less, and the balance is Al and unavoidable impurities.

The sixth aspect of the present invention is to use Al alloy as the core material and as the skin material.
In a heat exchanger constructed by vapor phase brazing, the tube material clad with 37 series or Zn-Al alloy brazing material is combined with the fin material made of Al2 or A7' alloy, and the core material contains Mg0.6 to 2. 5%, S, 1.0% or less,
Contains 1.2% or less of Fe, 2.0% or less of Mn, and further contains Z
It is characterized by using an Al alloy containing one or more of the following within the ranges of r0.3% or less, CroJ% or less, and NL 1.0% or less, with the remainder being Al and inevitable impurities. It is.

The seventh aspect of the present invention is that the core material is made of an Al alloy, and the skin material is made of Al.
- In a heat exchanger constructed by combining a tube material clad with a Si-based or Zn-Al alloy brazing material and a fin material made of Al or an Al alloy, and brazing the material, the core material contains Mg0.6 to 2. .5%, sz 1.0%
F, Fe 1.2% or less Cu1. Contains f1% or more, and further contains ZrO3% or less, Cr0.3% or less, N
It is characterized by using an Al alloy containing one or more of L within a range of 1.0% or less, and the remainder being Al and inevitable impurities.

The eighth aspect of the present invention is to use Al alloy as the core material and as the skin material.
- In a heat exchanger constructed by vapor phase brazing, combining a tube material clad with Si-based or Zn-Al-based alloy brazing material and a fin material made of Ae or Al alloy,
Core material: Mg 0.6-2.5%, SL 1.0% or less, Fe 1.2% or less, Mn 2.0% or less, Cu
Contains 1.0% or less, further Zr0.3% or less, Cr0
．． Less than 3%.

It is characterized by using an Al alloy containing one or more of J within a range of 1.0% or less, and the remainder being Al and unavoidable impurities.

Function] In the present invention, the alloy composition of the core material of the tube is limited as described above due to the following extrusion.

Addition of Mg has the function of improving the room temperature strength of the alloy and also improving the brazability in vapor phase brazing. However, the content was limited to 0.6 to 2.5% because 0.
If it is less than 6%, the strength will not be improved sufficiently, and if it exceeds 25%, the alloy will melt due to heating during brazing.

The addition of s2 has the function of improving the strength of the alloy. In particular, in this alloy, M g 2Sl is finely precipitated together with Mg to improve the strength. However, its content is +, oo
The reason why it is limited to 6 or more is that if it exceeds 1.0%, the melting point of the alloy will drop and the brazing will melt when heated.

Addition of Fe increases the high temperature strength of the alloy, and brazing has the effect of preventing IL from deformation during heating. However, the content was limited to 1.2% or less because if the content exceeds 1.2%, the crystal grain size becomes fine due to the effect of increasing the number of Al-Fe intermetallic compounds. This is because corrosion resistance is low.

The addition of Mn is Fe, l! : Combines with S and its precipitation ■1
is formed finely and densely in the core material, and the strength of the core material at high temperatures and room temperatures is improved by the action of dispersion strengthening of this precipitated phase. But does that include rN? The reason why t was limited to 2.0% or less was because
This is because if the content exceeds 2.0%, the rollability decreases, making it difficult to manufacture the tube material.

Addition of Cu functions to improve the strength of the alloy by forming a solid solution in the tube material. However, its Y content is 1.0%
The reason why the content is limited to the following is that if the content exceeds 10%, the high temperature strength decreases due to the effect of lowering the melting point of the alloy.

Zr0.3% or less, Cr0.3% or less, N11.0
Adding one or more of these within the range of % or less forms fine intermetallic compounds and has the effect of increasing the strength of the tube. However, the reason why the content is limited as described above is that exceeding the upper limit of any of them not only causes ingot cracking during casting, but also reduces the rolling resistance of the alloy.

The above is the alloy composition of the tube core material in the present invention, but as unavoidable impurities, TL and 81, which are added as grain refiners during casting, and Zn, which is added for the purpose of strength, formability, and castability. , Ca, V, BL, Pb, Ag
, Be and other elements each less than 0.05%, total acid content of 0,
It may contain less than 15%.

Next, the brazing filler metal, which is the outer skin of the core material, will be explained. wax ÷
The coverage ratio of No. 4 varies depending on the wall thickness of the tube, but is usually about 10%. The alloy to be used may be an alloy containing Al7 and about 6 to 10% SL, or an alloy containing Zn and about 5 to 22% Al. Unlike the brazing filler metal used in vacuum brazing, Mg may be contained, but it is not necessary to actively add Mg. Just by diffusing Mg in the core material into the brazing material, the performance of vapor phase brazing is sufficiently improved.

On the other hand, if a large amount of Mg is added to the brazing filler metal, Mg vapor is generated and the flow t'l of the brazing filler metal becomes low. Furthermore, the flowability of wax,
82. for the purpose of improving sacrificial effect, out-of-casting during tube manufacturing, workability, etc. Be.

Pb, In, Sn, T)-, B, etc. may be included.

It is particularly recommended that the tube of the present invention has a three-layer material with a sacrificial layer provided on the inside to enhance its anticorrosion effect. The thickness of the anti-corrosion layer is usually about 0.04 mm, and the alloy used for this is pure Al, Zn, M
g, L, 7-, Zn, Sn
.

It is an alloy that does not contain one or more of Ca and the like.

The tube material of the present invention is usually manufactured by rolling laminated plates and then welding them by electric resistance welding, and the plate thickness is usually about 0.1 to 0.4 mm.

Further, as the aluminum members other than the tube material, any of the alloys used in ordinary heat exchangers, such as 1050 alloy and 3003 alloy, can be used.

The heat exchanger of the present invention combines the above tube material and fin material and is constructed by brazing in a non-oxidizing atmosphere in the presence of flux vapor without applying flux to the assembly. By adding Mg, the brazing quality is improved. In other words, vapor phase brazing is performed in a non-oxidizing atmosphere by using flux vapor to destroy the oxide film on the surface of the material, but since Mg easily reacts with flux vapor, the flux vapor may damage the surface of the brazing material. This is because the flux vapor easily adheres to the surface of the brazing material, and the flux vapor destroys the oxide film on the surface of the brazing material. If the amount of flux vapor in an alloy to which Mg is not added is unstable, the cores of the flux will be difficult to adhere to the material surface, and the reaction between the flux vapor and the oxide film will be insufficient, causing failure in brazing. The reason why the addition of Mg improves the brazing properties is that the amount of flux used in vapor phase brazing is extremely small compared to conventional brazing in which flux is applied. Furthermore, by using vaporized flux in vapor phase brazing, the amount of flux used can be reduced and a structure with a clean surface condition can be obtained.

The non-corrosive flux vapor used here is KA/
Fl, K,! Al F,
, K(A IF 6 etc.) Potassium fluoroaluminate complexes represented by the general formula K n An F II , l, C5AlF4, C82A(l
F,,, Cs + Aj! Fl, etc. General formula C5
Cesium fluoroaluminate 11 expressed as nA/Fn□
Complex, KBF, , TguZ n F (, K S n F
+, Z r Ft, , S7 Fl, etc., and mixed vapors thereof are included. These flux vapors are produced by heating and evaporating the fluxes having the above composition, or KF+AlF.

Cs F + A I F 3. K F + Z
r F 4 + A l .

KF+LL FlAl, KF+SnF
2 +A l.

KF+ZnF4 +NaF+A/, LLF+NaF
+CsF+A/, L4F+CsF+Al.

CsFlPbF 2 +A I , KF+CsF+
Aj! .

It can be generated as a reaction product by heating and melting a mixture such as Cs FlZ r F4+Al'. These flux vapor generation methods include heating and evaporating the flux inside the furnace, heating and evaporating the flux outside the furnace, mixing it with non-oxidizing gas such as nitrogen and argon, and introducing it into the furnace. Either method can be used.

〔Example〕

The present invention will be described below with reference to Examples.

The radiator core shown in FIG. 1 was assembled, fixed with a jig, and brazed. That is, Nα1~ in Table 1
The Al alloy with the composition shown in 15 is used as the core material, and B is placed on the outside.
A 0.3 mm thick electric resistance welded tube (1) clad with 10% 4343 alloy (Al-7,5% SL alloy) as a brazing material and 10% 7072 alloy (CA1-1% alloy) as a sacrificial material on the inside. and A between the tubes (1).
[-1%Mn-1%Zn alloy with thickness 0. Imm corrugated fins (2) are provided, and 3003 alloy (Al-1,2%Mn-0.1%Cu) is installed at both ends of the tube (1).
8% B A 4343 alloy on one side and 7% on the back side.
A 1.6mm thick header plate (3) made of 10% 072 alloy is installed, and 3003 alloy is installed on both sides.
A side plate (5) with a thickness of 1.2 mm made of BAlIPC clad with 10% B A 4343 alloy was attached to one side of the alloy to form a radiator core, and this was fixed with a jig. In the figure, (5) shows a plastic tank that will be installed later.

After degreasing this assembly with an organic solvent, it was placed on a stainless steel tray and placed in a nitrogen gas atmosphere containing Flags steam with a partial pressure of 5 QmmHg, an oxygen partial pressure of 5mmHg, and a water vapor partial pressure of IQmmHg. The radiator core was prepared by placing the core in an electric furnace maintained at 610°C, and heating it at 610°C for 5 minutes to perform brazing. This radiator core was taken out of the furnace and the brazing situation was investigated. The results are shown in Table 2. We also apply internal pressure to the radiator core and measure the pressure at which the tube deforms.
This pressure is also listed in Table 2 as the compressive strength.

For comparison, an alloy (300
3 alloy) as the core material, and B A 434 on the outside.
3 alloy as a brazing material, 10% (7072 to 1111)
An electric resistance welded tube with a wall thickness of 0.3 mark, clad with 10% alloy as a sacrificial material, was used to create a radiator core in the same manner as in the above example, and its evaluation was performed. The results are also listed in Table 2.

For comparison, a radiator core was prepared by Roconock, in which a fluoride-based flux was applied to the assembly and brazed in a furnace, and the same evaluation as in the above example was conducted. The results are also listed in Table 2. That is, Nul in Table 1
An electric resistance welded tube similar to that described above was formed using alloys having the compositions shown in 1 to 5 as core materials, and the corrugated fins, header plates, and side plates described above were combined therewith to form the radiator core shown in FIG. 1. After fixing this with a jig and degreasing it with an organic solvent, the assembly was coated with a 10% concentration KAlF4+ and AlFh mixture and dried at 200°C for 10 minutes. This is set to an oxygen partial pressure of 5 mmHg and a water vapor partial pressure of 10 mm.
The material was placed in an electric furnace purged with a nitrogen gas atmosphere containing Hg and maintained at 610'C, and brazing was performed at 1°C for 5 minutes.

As is clear from Table 1 and Table 2, the radiator according to the present invention has good brazing properties and high compressive strength despite the high Mg content.

On the other hand, in the comparative example, the brazing was sound, but
Since the compressive strength is low and the conventional example has a high Mg content, the reaction between the flux and Mg results in poor brazing, making it impossible to obtain a sound radiator.

[Effects of the Invention] As described above, the heat exchanger of the present invention has excellent brazing properties, high pressure resistance, and has industrially significant effects such as making it possible to reduce the weight of the heat exchanger by making the tubes thinner. It is something that plays.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of a radiator for an automobile. 1...Tube 2...Corrugated fin 3/Header plate 4...Side plate...Plastic tank

Claims (8)

[Claims] (1) A tube material made of Al alloy as a core material and clad with Al-Si or Zn-Al alloy brazing material as the outer skin, and a fin material made of Al or Al alloy are combined and constructed by vapor phase brazing. In exchangers, Mg is added to the core material.
0.6-2.5wt%, Si1.0wt% or less, Fe1
．． An aluminum alloy heat exchanger characterized by using an Al alloy containing 2 wt% or less, with the remainder being Al and inevitable impurities. (2) A tube material made of an Al alloy as a core material and clad with an Al-Si or Zn-Al alloy brazing material as a skin material, and a fin material made of Al or an Al alloy are combined and constructed by vapor phase brazing. In heat exchangers, Mg is added to the core material.
0.6-2.5wt%, Si1.0wt% or less, Fe1
．． 2 wt% or less, Mn 2.0 wt% or less, the balance A
1. An aluminum alloy heat exchanger characterized by using an Al alloy consisting of aluminum and inevitable impurities. (3) A tube material made of an Al alloy as a core material and clad with an Al-Si or Zn-Al alloy brazing material as a skin material, and a fin material made of Al or an Al alloy are combined and constructed by vapor phase brazing. In heat exchangers, Mg is added to the core material.
0.6-2.5wt%, Si1.0wt% or less, Fe1
．． 2wt% or less, including Cu1.0wt% or less, the balance A
1. An aluminum alloy heat exchanger characterized by using an Al alloy consisting of aluminum and inevitable impurities. (4) A tube material made of an Al alloy as a core material and clad with an Al-Si or Zn-Al alloy brazing material as a skin material, and a fin material made of Al or an Al alloy are combined and constructed by vapor phase brazing. In heat exchangers, Mg is added to the core material.
0.6-2.5wt%, Si1.0wt% or less, Fe1
．． Contains 2wt% or less, and further contains Zr0.3wt% or less, C
An aluminum alloy heat exchanger characterized by using an Al alloy containing one or more of r0.3wt% or less and Ni1.0wt% or less, the balance being Al and inevitable impurities. . (5) A tube material made of an Al alloy as a core material and clad with an Al-Si or Zn-Al alloy brazing material as a skin material, and a fin material made of Al or an Al alloy are combined and constructed by vapor phase brazing. In heat exchangers, Mg is added to the core material.
0.6-2.5wt%, Si1.0wt% or less, Fe1
．． 2wt% or less, Mn2.0wt% or less, Cu1.0w
t% or less, with the remainder consisting of Al and unavoidable impurities
An aluminum alloy heat exchanger characterized by using L alloy. (6) A tube material made of an Al alloy as a core material and clad with an Al-Si or Zn-Al alloy brazing material as a skin material, and a fin material made of Al or an Al alloy are combined and constructed by vapor phase brazing. In heat exchangers, Mg is added to the core material.
0.6-2.5wt%, Si1.0wt% or less, Fe1
．． 2 wt% or less, Mn 2.0 wt% or less, and further Z
r0.3wt% or less, Cr0.3wt% or less, Ni1.
An aluminum alloy heat exchanger characterized by using an Al alloy containing one or more of these within a range of 0 wt% or less, with the balance being Al and inevitable impurities. (7) A tube material made of an Al alloy as a core material and clad with an Al-Si or Zn-Al alloy brazing material as a skin material, and a fin material made of Al or an Al alloy are combined and constructed by vapor phase brazing. In heat exchangers, Mg is added to the core material.
0.6-2.5wt%, Si1.0wt% or less, Fe1
．． 2wt% or less, Cu1.0wt% or less, and further Z
r0.3wt% or less, Cr0.3wt% or less, Ni1.
An aluminum alloy heat exchanger characterized by using an Al alloy containing one or more of these within a range of 0 wt% or less, with the balance being Al and inevitable impurities. (8) A tube material made of an Al alloy as a core material and clad with an Al-Si or Zn-Al alloy brazing material as a skin material, and a fin material made of Al or an Al alloy are combined and constructed by vapor phase brazing. In heat exchangers, Mg is added to the core material.
0.6-2.5wt%, Si1.0wt% or less, Fe1
．． 2wt% or less, Mn2.0wt% or less, Cu1.0w
t% or less, and further contains Zr0.3wt% or less, Cr0.
An aluminum alloy heat exchanger characterized by using an Al alloy containing one or more of Ni in the range of 3 wt% or less and Ni of 1.0 wt% or less, and the balance being Al and inevitable impurities.