JP3396523B2 - Al alloy fin material with excellent post-brazing strength and brazing properties - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fin material used in a heat exchanger for automobiles manufactured by a brazing method.

[0002]

2. Description of the Related Art Al alloys are light and have excellent thermal conductivity, and
Because of its good corrosion resistance, it is widely used in the production of heat exchangers for automobile radiators and the like. In an aluminum alloy heat exchanger, for example, a working fluid passage material (hereinafter referred to as a tube material) made of an Al-Mn alloy or the like is assembled by brazing a fin material of an aluminum alloy electrochemically less than this material. ing. The working fluid passage material is protected from corrosion by the sacrificial anode effect of the electrochemically base fin material.

Brazing is carried out by heating the combination of the tube material and the fin material to the brazing temperature in a vacuum or by heating with a flux in an inert atmosphere or in the air. For at least one of the pipe material and the fin material, a brazing sheet in which a brazing material such as Al-Si system or Al-Si-Mg system is clad is used, and the fin material is heated by high temperature during brazing. The strength of the brazing filler metal is remarkably reduced and it is deformed, or Si atoms in the brazing filler metal are diffused into the fin rod and buckled. Such significant deformation and buckling of the fin material occurs due to local melting of the material during heating for brazing (hereinafter, the property of not causing such deformation and buckling is referred to as brazing property).

The fin material for the aluminum alloy heat exchanger is required to have sufficient strength so as not to be deformed by wind pressure when the heat exchanger is used after brazing. Furthermore, it is important that the hot workability at the time of manufacturing the fin material is excellent.

Therefore, in order to improve the characteristics of the fin material of the aluminum alloy heat exchanger as described above, about 1% is required.
Al-Mn-based alloy containing Mn, Al-Mn-Si-based alloy containing about 1% Si to improve the strength after brazing, and further containing various elements below. Technology is proposed. As a technique for improving the strength after brazing of a fin material made of a heat exchanger Al alloy, and brazing property, for example, JP-A-58-156197 (hereinafter referred to as prior art 1)
JP-A-63-213646 (hereinafter referred to as prior art 2)
And Japanese Patent Laid-Open No. 3-13550 (hereinafter, referred to as prior art 3
There is).

[0006] Prior art 1 relates to an A3004 alloy used for fins, and during brazing, Si in the Al-Si alloy brazing material is excessively diffused into the fin material and locally melts, so that the width of the brazing joint is significantly reduced. The present invention discloses an Al alloy containing 0.05 to 0.25% Cu for the purpose of providing a plate fin type heat exchanger for ultra-high pressure and preventing the joint strength from decreasing.

In prior art 2, when the fin material and the pipe material are vacuum-brazed, the sacrificial anode effect on the pipe material is prevented from lowering due to the evaporation of Zn in the fin material, and the high temperature strength (droop resistance) and brazing In order to secure the strength after attachment, a composite material is disclosed in which an Al alloy skin material containing 0.03 to 0.15% Sn is clad on both sides of an Al alloy core material.

The prior art 3 is a so-called room temperature buckling resistance which is high temperature buckling resistance and when the fin material is made thin, the fin is crushed when corrugating the fin to assemble the pipe material due to insufficient strength. For the purpose of manufacturing a fin material that also has high strength to prevent generation, it contains final Cr, Zr, Ti and V, and is annealed before the final cold rolling at 240 to 300 ° C.
Less than the normal annealing temperature (300
(~ 450 ° C) is disclosed.

[0009]

However, in all of the prior arts 1 to 3, Si contained to improve the strength after brazing exerts its effect, but on the other hand, it depends on the brazing conditions. Depending on the conditions, when the fin material is heated to the brazing temperature, it forms a solid solution in the fin material.
The action of Si lowers the solidus temperature of the material and may cause local melting. Thus, in the prior arts 1 to 3,
There is a problem with the brazing property, and in particular, such a phenomenon becomes noticeable when the plate thickness of the Al alloy fin material is thin, so it is not possible to sufficiently meet the recently increasing demand for thinning of the fin material. .

Therefore, an object of the present invention is to solve the above-mentioned problems and to use an Al alloy fin excellent in strength after brazing and brazability, which is used in a heat exchanger for automobiles manufactured by a brazing method. Is to provide wood.

[0011]

Means for Solving the Problems The inventors of the present invention have earnestly studied an Al alloy fin material having excellent strength after brazing and brazing property, and have obtained the following findings. That is, Al-
Mn in the Mn-Si-based Al alloy has an action of promoting the precipitation of Si as an Al-Mn-Si-based precipitate and suppresses the solid solution amount of Si. The effect of preventing the solidus temperature of the alloy from decreasing and the coexistence of the three elements V, Zr, and Cr are incorporated into the Al-Mn-Si-based precipitates, and in these precipitates Si content ratio of
Since the solid solution amount of Si is reduced, the decrease in the solidus temperature of the Al alloy is suppressed.

The present invention has been made on the basis of the above findings, and in order to achieve the object of the present invention, the content of Mn was increased, and the three elements of V, Zr and Cr coexisted. It has a remarkable feature in simultaneously satisfying the above requirements. That is, the Al alloy fin material of the first invention is
In weight%, Si: 0.7 ~1.5%, Mn: 1.5 super ~3%, V: 0.01
~ 0.25%, Zr: 0.01-0.25%, and Cr: 0.01-0.25
%, And the remainder has a chemical composition of Al and inevitable impurities.

The Al alloy fin material according to the second aspect of the present invention is, by weight%,
Si: 0.7 ~1.5%, Mn: 1.5 super ~3%, V: 0.01~0.25%, Z
r: 0.01 to 0.25%, Cr: 0.01 to 0.25%, Fe: 0.2 to 1.5% and Ti: 0.02 to 0.25%
Among them, at least one is contained, and the rest is characterized by having a chemical composition of Al and inevitable impurities.

The Al alloy fin material according to the third aspect of the present invention is, by weight%,
Si: 0.7 ~1.5%, Mn: 1.5 super ~3%, V: 0.01~0.25%, Z
r: 0.01 to 0.25%, Cr: 0.01 to 0.25%, and Mg: 0.05
It is characterized by having a chemical composition of 0.1 to 0.3% and the balance being Al and inevitable impurities.

The Al alloy fin material according to the fourth aspect of the present invention, in% by weight,
Si: 0.7 ~1.5%, Mn: 1.5 super ~3%, V: 0.01~0.25%, Z
r: 0.01 to 0.25%, Cr: 0.01 to 0.25%, and Mg: 0.05
To 0.3%, further Fe: 0.2 to 1.5% and Ti:
At least one of 0.02 to 0.25% is contained, and the rest is
It is characterized by having a chemical composition composed of Al and unavoidable impurities.

The Al alloy fin material according to the fifth aspect of the present invention is, by weight%,
Si: 0.7 ~1.5%, Mn: 1.5 super ~3%, V: 0.01~0.25%, Z
r: 0.01 to 0.25%, Cr: 0.01 to 0.25%, Zn: 0.3 to 2%, Sn: 0.02 to 0.2%, and I
It is characterized by containing at least one of n: 0.005 to 0.05% and the rest having a chemical composition of Al and inevitable impurities.

The Al alloy fin material according to the sixth aspect of the present invention is, by weight%,
Si: 0.7 ~1.5%, Mn: 2.0 super ~3%, V: 0.01~0.25%, Z
r: 0.01 to 0.25%, Cr: 0.01 to 0.25%, Fe: 0.2 to 1.5% and Ti: 0.02 to 0.25%
Of these, at least one, Zn: 0.3 to 2%, Sn: 0.
It is characterized by containing at least one of 02 to 0.2% and In: 0.005 to 0.05%, and the rest having a chemical composition of Al and unavoidable impurities.

The Al alloy fin material according to the seventh aspect of the present invention, in% by weight,
Si: 0.7 ~1.5%, Mn: 2.0 super ~3%, V: 0.01~0.25%, Z
r: 0.01 to 0.25%, Cr: 0.01 to 0.25%, and Mg: 0.05
~ 0.3%, further Zn: 0.3 ~ 2%, Sn: 0.02 ~ 0.2
%, And In: 0.005 to 0.05%, at least one of them is contained, and the remainder has a chemical composition of Al and inevitable impurities.

The Al alloy fin material of the eighth invention is, by weight%,
Si: 0.7 ~1.5%, Mn: 2.2 super ~3%, V: 0.01~0.25%, Z
r: 0.01 to 0.25%, Cr: 0.01 to 0.25%, and Mg: 0.05
To 0.3%, further Fe: 0.2 to 1.5% and Ti:
At least one of 0.02 to 0.25% and Zn: 0.3
.About.2%, Sn: 0.02 to 0.2%, and In: 0.005 to 0.05%, and at least one of them is contained, and the balance is characterized by having a chemical composition of Al and unavoidable impurities. is there.

[0020]

The function of the chemical composition of the Al alloy fin material according to the present invention will be described below. (1) Si: Si is a solid solution in Al alloy, or Al-Mn-S
It has the function of precipitating as an i-based compound and improving the strength after brazing. However, if its content is less than 0.7%, its effect is insufficient. On the other hand, if it exceeds 1.5%, the amount of solid solution becomes excessive and the solidus temperature falls below the brazing temperature to cause local melting. Therefore, the Si content is 0.7-
Should be within 1.5%.

(2) The content of Mn: Mn is higher than that of the prior art and is the most characteristic element in the present invention. Mn is
Si has the action of promoting precipitation as an Al-Mn-Si-based compound and suppresses the amount of solid solution of Si.
It has the effect of preventing the solidus temperature of the Al alloy from decreasing and preventing local melting. However, if the content is less than 1.5%, the effect is insufficient, while if it exceeds 3%, the hot workability deteriorates in the hot working step during the manufacturing process of the Al alloy sheet material. Therefore, the Mn content should be in the range of 1.5-3%.

(3) V, Zr and Cr: In the present invention, V
It is a characteristic that the chemical composition is such that the three elements of Zr, Zr, and Cr coexist in comparison with the technical idea of the prior art. When V, Zr, and Cr coexist with these three elements, these three elements are incorporated into Al-Mn-Si-based precipitates,
The Si content ratio in this precipitate is increased, the solid solution amount of Si is decreased, and in order to promote the precipitation of Al-Mn-Si-based precipitates,
It has an effect of suppressing a decrease in solidus temperature of the Al alloy and an effect of suppressing local melting. However, if the contents of V, Zr and Cr are all less than 0.01%, the above effect is insufficient, while the contents of V, Zr and Cr are all
If it exceeds 0.25%, the hot workability deteriorates in the hot working process during the manufacturing process of the Al alloy plate material. Therefore, the contents of V, Zr and Cr should all be within the range of 0.01 to 0.25%.

(4) Fe and Ti: Fe and Ti are Al-Mn-S
It has the effect of refining i-based precipitates and has the effect of improving the strength after brazing. However, if the Fe content is less than 0.2% and the Ti content is less than 0.02%, the effect is insufficient, while the Fe content exceeds 1.5% and the Ti content is
If it exceeds 0.25%, the hot workability deteriorates in the hot working process during the manufacturing process of the Al alloy plate material. Therefore, the Fe content is 0.2
~ 1.5%, Ti content should be in the range of 0.02 to 0.25%.

(5) Mg: Mg has the effect of improving the strength after brazing. However, its content is 0.05
If it is less than%, the effect of improving the strength after brazing is insufficient, while if it exceeds 0.3%, the solidus temperature falls below the brazing temperature and local melting occurs. Therefore, the content of Mg is 0.05 ~
It should be within 0.3%.

(6) Zn, Sn and In: Zn, Sn and In are
Both have a function of making the electrochemical potential of the Al alloy base, and impart a sacrificial anode effect. However, the Zn content is less than 0.3%, the Sn content is less than 0.02%, and the In content is
If less than 0.005%, the effect is insufficient, while the Zn content exceeds 2%, the Sn content exceeds 0.2%, and the In content is 0.05%.
If it exceeds%, the electrochemical potential becomes too low and the self-corrosion rate becomes too high. Therefore, the Zn content is 0.3-2.
%, Sn content is 0.02 to 0.2%, In content is 0.005 to 0.0
Should be within 5%.

[0026]

EXAMPLES Next, the present invention will be described by way of examples in comparison with comparative examples. Nos. I-1 to 42 having the chemical composition within the scope of the present invention shown in Tables 1 and 2 and the reference
No. I-43 for No. I-43 , and No. C-1-25 Al alloy melts having chemical composition outside the scope of the present invention shown in Tables 3 and 4, were prepared. A slab with a size of 400 mm and a thickness of 50 mm was cast, and then the slab was homogenized and then hot rolled to form a hot-rolled sheet with a thickness of 5 mm, and then intermediate annealing and cold rolling were repeated. Giving, thickness 0.1
An Al alloy fin material was manufactured as a cold-rolled sheet of mm.

[0027]

[Table 1]

[0028]

[Table 2]

[0029]

[Table 3]

[0030]

[Table 4]

In order to evaluate the hot workability in the manufacturing process of the Al alloy sheet material, the presence or absence of cracks on the surface of the hot rolled sheet was visually inspected.

Furthermore, a test material is sampled from the Al alloy fin material having a thickness of 0.1 mm, and the condition is equivalent to vacuum brazing. After performing the above, a predetermined test piece was prepared and subjected to a tensile test, a solidus temperature measurement, and a pitting corrosion generation potential measurement. A Shimadzu DTA-50 type tester was used to measure the solidus temperature. The measurement results of the above various tests are shown in Tables 5, 6 and 7.

[0033]

[Table 5]

[0034]

[Table 6]

[0035]

[Table 7]

The following matters are clear from Tables 1 to 7. Regarding the tensile strength, some of the comparative Al alloy fin materials had insufficient strength, such as No. C-3, but the Al alloy fin material of the present invention had such insufficient strength. In addition, the same excellent strength was obtained as compared with the conventional Al alloy fin material.

Regarding the solidus temperature, Nos. C-1,4,5,7,9,14 and 15 of the comparative Al alloy fin materials are as low as 614 to 618 ° C., which is about the same as the conventional Al alloy fin materials. It was very low and did not improve the brazability. On the other hand, all of the Al alloy fin materials of the present invention had a high temperature of 638 to 655 ° C, and the brazing property was remarkably improved.

Regarding the pitting occurrence potential, -1.10 to -0.60
Whereas V _VS SCE is the desired potential, Comparative Al alloy fin materials No. C-16 to 23 are -1.45 to -1.22 V _VS SCE, and the electrochemical potential becomes too base in both cases. , The self-corrosion rate became too high. On the other hand, the pitting corrosion potentials of the Al alloy fin materials of the present invention are all -0.98 to -0.77V _VS S
It was CE, and the desired sacrificial anode effect was obtained. Regarding the cracks during hot rolling,
No. C-2, 6, 8 and 10 to 13 but not in the Al alloy fin material of the present invention.

As described above, the Al alloy fin material of the present invention is significantly improved in brazability as compared with the conventional Al alloy fin material and the comparative Al alloy fin material, and the strength after brazing is improved in the conventional Al alloy fin material. It is as good as the fin material, the sacrificial anode effect is equivalent to the conventional and comparative Al alloy fin materials, and the hot workability of the Al alloy in the fin manufacturing process is also the conventional and comparative Al alloy fin materials. It was as good as or better than the wood.

[0040]

As described above, according to the Al alloy fin material of the present invention, local melting does not occur at the time of heating for brazing, no defective brazing occurs, excellent brazing property is obtained, and An Al alloy fin material that is as excellent in strength after brazing as the conventional alloy fin material can be obtained, and an industrially useful effect that can sufficiently meet the demand for thinning of the Al alloy fin material is brought about.

Continuation of the front page (56) Reference JP-A-3-100143 (JP, A) JP-A-3-94037 (JP, A) JP-A-2-305946 (JP, A) JP-A-5-239578 (JP , A) JP 5-230578 (JP, A) JP 63-213646 (JP, A) JP 7-70684 (JP, A) JP 7-138686 (JP, A) JP 7-145439 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C22C 21/00-21/18 F28F 21/08

Claims (8)

(57) [Claims] 1. By weight%, silicon (Si): 0.7 to 1.5%, manganese (Mn): more than 1.5 to 3%, vanadium (V): 0.01 to 0.25%, zirconium (Zr): 0.01 to 0.25%, Also, chromium (Cr): 0.01 to 0.25%, and the balance having a chemical composition of Al and unavoidable impurities, the Al alloy fin having excellent strength after brazing and brazing property. Material. 2. In weight%, silicon (Si): 0.7 to 1.5%, manganese (Mn): more than 1.5 to 3%, vanadium (V): 0.01 to 0.25%, zirconium (Zr): 0.01 to 0.25%, And chromium (Cr): 0.01 to 0.25%, and further contains at least one of iron (Fe): 0.2 to 1.5% and titanium (Ti): 0.02 to 0.25%, An Al alloy fin material excellent in strength after brazing and brazing property, characterized in that the rest has a chemical composition of Al and inevitable impurities. 3. In weight%, silicon (Si): 0.7 to 1.5%, manganese (Mn): more than 1.5 to 3%, vanadium (V): 0.01 to 0.25%, zirconium (Zr): 0.01 to 0.25%, Strength after brazing, characterized by containing chromium (Cr): 0.01 to 0.25% and magnesium (Mg): 0.05 to 0.3%, and the balance having a chemical composition of Al and inevitable impurities. And an Al alloy fin material with excellent brazing properties. 4. In weight%, silicon (Si): 0.7 to 1.5%, manganese (Mn): more than 1.5 to 3%, vanadium (V): 0.01 to 0.25%, zirconium (Zr): 0.01 to 0.25%, Chromium (Cr): 0.01-0.25% and magnesium (Mg): 0.05-0.3% are contained, and further iron (Fe): 0.2-1.5% and titanium (Ti): 0.02-0.25%, Among these, an Al alloy fin material excellent in strength after brazing and brazing property, characterized by containing at least one kind and the rest having a chemical composition of Al and inevitable impurities. 5. In weight%, silicon (Si): 0.7 to 1.5%, manganese (Mn): more than 1.5 to 3%, vanadium (V): 0.01 to 0.25%, zirconium (Zr): 0.01 to 0.25%, And chromium (Cr): 0.01 to 0.25%, further containing zinc (Zn): 0.3 to 2%, tin (Sn): 0.02 to 0.2%, and indium (In): 0.005 to 0.05%, Among them, an Al alloy fin material excellent in strength after brazing and brazing property, characterized by containing at least one kind and the rest having a chemical composition of Al and inevitable impurities. 6. In weight%, silicon (Si): 0.7 to 1.5%, manganese (Mn): over 2.0 to 3%, vanadium (V): 0.01 to 0.25%, zirconium (Zr): 0.01 to 0.25%, And chromium (Cr): 0.01 to 0.25%, and further, iron (Fe): 0.2 to 1.5%, and titanium (Ti): 0.02 to 0.25%, at least one type, and zinc (Zn): 0.3 to 2%, tin (Sn): 0.02 to 0.2%, and indium (In): 0.005 to 0.05%, containing at least one kind, and the rest consisting of Al and unavoidable impurities. An Al alloy fin material excellent in strength after brazing and brazability, characterized by having a chemical composition. 7. In weight%, silicon (Si): 0.7 to 1.5%, manganese (Mn): over 2.0 to 3%, vanadium (V): 0.01 to 0.25%, zirconium (Zr): 0.01 to 0.25%, Chromium (Cr): 0.01 to 0.25% and magnesium (Mg): 0.05 to 0.3% are further contained, and zinc (Zn): 0.3 to 2%, tin (Sn): 0.02 to 0.2%, and Indium (In): 0.005 to 0.05%, containing at least one kind, and the rest having a chemical composition of Al and unavoidable impurities, which is excellent in strength after brazing and brazing property. Al alloy fin material. 8. In weight%, silicon (Si): 0.7 to 1.5%, manganese (Mn): more than 2.2 to 3%, vanadium (V): 0.01 to 0.25%, zirconium (Zr): 0.01 to 0.25%, Chromium (Cr): 0.01-0.25% and magnesium (Mg): 0.05-0.3% are contained, and further iron (Fe): 0.2-1.5% and titanium (Ti): 0.02-0.25%, At least one of, and zinc (Zn): 0.3 to 2%, tin (Sn): 0.02 to 0.2%, and indium (In): 0.005 to 0.05%, at least one of An Al alloy fin material excellent in strength after brazing and brazability, characterized in that the rest has a chemical composition of Al and inevitable impurities.