JPH04263033A - Aluminum clad material for heat exchanger - Google Patents

Abstract

PURPOSE:To improve the strength, brazability, and corrosion resistance of an aluminum clad material for heat exchanger used for a tube material for heat exchanger made of aluminum, particularly radiator made of aluminum. CONSTITUTION:One side of an aluminum alloy core material which has a composition consisting of 0.3-1.5% Mn, 0.2-0.9% Cu, 0.2-0.5% Mg, 0.2-1.0% Si, 0.10-0.7% Fe, 0.10-0.3% Ti, and the balance Al with inevitable impurities or further containing 0.05-0.2% Zr and/or 0.05-0.2% Cr is clad with an aluminum alloy cladding material having a composition consisting of 0.3-2.0% Zn, 0.2-1.0% Mg, and the balance Al with inevitable impurities, and further, the other side is clad with an Al-Si alloy brazing filler metal.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum heat exchanger, particularly an aluminum clad material suitable as a tube material for an aluminum radiator.

0002

[Prior Art] Conventionally, the core material of aluminum heat exchangers, especially radiator tubes, has been made according to JIS 30.
03 alloy, one side of which is clad with an Al-Si alloy brazing filler metal, and the other side of which is clad with an Al-Zn alloy. Al-
An electric resistance welded flat tube is used with the Zn alloy side on the inside and the Al-Si alloy side on the brazing metal side outside, and is used as a tube material for a radiator. The Al-Si alloy brazing material on the outside of the ERW flat tube is necessary for joining the aluminum fins by brazing, and the Al-Zn alloy on the inside acts as a sacrificial anode material for the core material and cools it. Prevents corrosion of tube material due to water. Recently, so-called sawlock brazing using fluoride flux has been frequently used to braze such tube materials and fin materials.

0003

[Problems to be Solved by the Invention] Recently, due to the desire to reduce the weight of radiators, there has been a demand for thinner materials, and in order to ensure the necessary strength, it has become necessary to improve the strength of aluminum materials. Adding Mg to the core material is effective for improving strength. On the other hand, in brazing using fluoride flux, Mg in the core material diffuses to the surface through the brazing material layer and reacts with the flux to form MgF2. Mg
Forms a thin film of F2, which impairs brazing properties. Therefore, a large amount of Mg cannot be added to the tube core material.

0004

[Means for Solving the Problems] In view of this, and as a result of various studies, the present invention has developed an aluminum clad material for heat exchangers that has high strength and good brazing properties.

That is, one of the cladding materials of the present invention is Mn 0
．． 3 to 1.5 wt% (hereinafter wt% is abbreviated as %), Cu
0.2-0.9%, Mg 0.2-0.5%, S
i 0.2~1.0%, Fe0.10~0.7%
, Ti 0.10-0.3%, and the remainder Al and unavoidable impurities. Zn 0.3-2.0%, Mg 0.2-1.0
%, with the remainder being Al and unavoidable impurities, is clad, and the other side is clad with an Al-Si alloy brazing material.

Another cladding material of the present invention is Mn 0
．． 3-1.5%, Cu 0.2-0.9%, Mg0
．． 2-0.5%, Si 0.2-1.0%, Fe
0.10-0.7%, Ti 0.10-0.3
%, and further contains Zr 0.05 to 0.2%, Cr
Zn0.3 to 2.0%, Mg 0.2 on one side of an aluminum alloy core material containing one or two of 0.05 to 0.2%, with the remainder being Al and inevitable impurities.
~1.0%, with the remainder being Al and unavoidable impurities, is clad, and the other side is coated with A.
It is characterized by being clad with an l-Si alloy brazing filler metal.

[0007]

[Function] That is, the cladding material of the present invention has the above-mentioned structure, and the amount of Mg contained in the core material is suppressed as much as possible in order to improve brazing properties, and the strength is increased. That is, during brazing, Mg in the core material diffuses to the brazing material side and impairs brazing properties, while it also diffuses to the Al-Zn alloy side, reducing the amount of Mg in the core material and lowering the strength. In order to suppress diffusion toward the Al-Zn alloy side, it is sufficient to add Mg to the Al-Zn alloy in advance.More effectively, by increasing the amount of Mg in the Al-Zn alloy, it is necessary to add Mg to the core material during brazing. is diffused into the Si in the core material.
g2 Si is made to improve strength. In this case, Mg in the Al-Zn alloy diffuses to the core material during brazing, but does not diffuse to the surface of the brazing material, so it does not impair brazability.

[0008] Mn in the core material is effective in improving strength, but if it is less than 0.3%, a sufficient effect in improving strength cannot be obtained, and if it exceeds 1.5%, coarse Al6Mn compounds are formed. Crystallization is not desirable. Cu not only improves strength but also
It is effective in improving corrosion resistance by shifting the potential of the core material to the noble side, but if it is less than 0.2%, it is insufficient, and if it exceeds 0.9%, the electric resistance welding properties deteriorate and at the same time corrosion resistance deteriorates.

[0009] Mg is effective in improving strength, but 0.2
If it is less than 0.5%, the effect will be insufficient, and if it exceeds 0.5%, brazing properties will deteriorate. Si coexists with Mg and Mg2
It precipitates Si and is effective in improving strength, but less than 0.2% is insufficient, and more than 1.0% tends to cause local melting during brazing.

[0010] Although Fe works effectively during casting and manufacturing of electric resistance welded pipes, making the structure finer and preventing cracking during solidification,
．． If it is less than 1%, the effect is insufficient, and if it exceeds 0.7%, coarse compounds are produced and corrosion resistance is also impaired.

[0011] Ti is effective in improving corrosion resistance and slows down the progress of pitting corrosion, but if it is less than 0.1%, the effect is insufficient, and if it exceeds 0.3%, it forms coarse compounds, which is not preferable. .

Addition of Zr and/or Cr is effective for improving strength, but less than 0.05% of either is insufficient;
If it exceeds 0.2%, coarse compounds will be formed, which is not preferable.

[0013] Zn in the skin material is an essential component for making the skin material electrochemically less noble with respect to the core material to form a sacrificial corrosion layer.
If it is less than 0.3%, the effect is weak, and if it exceeds 2.0%, the effect is saturated.

[0014] Furthermore, Mg in the skin material prevents Mg from diffusing from the core material to the skin material during brazing, and further diffuses from the skin material into the core material to form Si and Mg2Si in the core material. , extremely effective in improving strength. In this case, Mg is added to the core material in advance.
Since it is contained in an amount of 0.2 to 0.5%, the strength is stabilized. However, if Mg in the skin material is less than 0.2%, the effect will be small, and if it exceeds 1.0%, the corrosion resistance of the skin material will deteriorate.

[0015] As the Al--Si alloy brazing material to be clad on the other side, a normal Al--Si alloy brazing material may be used. For example, JIS BA 4343, B
A4045 etc.

[0016]

[Examples] Examples of the present invention will be described below. Table 1
A three-layer cladding material consisting of a core material, a brazing material, and a sacrificial material shown in Table 2 was prepared using a conventional manufacturing method. That is, the thickness of the core material is 40 mm, the thickness of the brazing material is 5 mm, and the thickness of the sacrificial material is 5 mm.
They were stacked together, hot-rolled, then cold-rolled, and then intermediately annealed to produce a cladding material with a thickness of 0.3 mm.

[0017] Using this cladding material, as shown in Fig. 1, two cladding materials (1) are arranged so that the brazing metals face each other, and a JIS 3003 alloy fin (2) is installed between the cladding materials (1). The brazeability test piece was assembled using a holding jig (3), and after applying fluoride flux, it was heated to 600°C for 3 minutes in nitrogen gas to perform brazing. I looked into it. Regarding the cladding material itself, a fluoride flux was applied to the brazing material side and dried, then heated to 600°C for 3 minutes in nitrogen gas and cooled at a rate of 100°C/min. A tensile test was conducted on this after one week, and a corrosion resistance test was also conducted. These results are shown in Table 3.

[0018] Brazing properties were determined by determining the number of fillets that were successfully formed at 100 joint locations between the fin and the clad material. The corrosion resistance test was conducted at a distance of 50 mm from the brazing heating material.
Cut out a 50mm test piece, seal the brazing metal side, and
The maximum pitting depth was measured by immersing the sample in water containing 10 ppm of u2+, heating it at 90°C for 8 hours, and then allowing it to cool for 16 hours for 90 cycles.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

[Table 3]

As can be seen from Tables 1 and 2, the cladding material of the present invention has high strength and excellent brazing properties and corrosion resistance. On the other hand, it can be seen that the comparative cladding materials in which the compositions of the core material and sacrificial material of the cladding material deviate from those of the present invention are inferior in strength, brazing properties, and corrosion resistance.

[0023]

[Effects of the Invention] As described above, according to the present invention, it is possible to obtain an aluminum clad material for a heat exchanger that has high strength and excellent brazing properties and corrosion resistance as a tube material for an aluminum heat exchanger, particularly an aluminum radiator. It has a remarkable effect.

[Brief explanation of the drawing]

FIG. 1 is a side view showing a brazeability test piece.

[Explanation of symbols]

1 Clad material of the present invention 2 JIS 3003 alloy fin 3 Presser jig

Claims (2)

[Claims] [Claim 1] Mn 0.3-1.5 wt%, Cu
0.2-0.9 wt%, Mg 0.2-0.5wt
%, Si 0.2-1.0 wt%, Fe 0.10
~0.7 wt%, Ti 0.10 ~0.3 wt%
Zn0.3 to 2.0 wt%,
A heat exchanger characterized by cladding an aluminum alloy skin material containing 0.2 to 1.0 wt% Mg and the remainder consisting of Al and unavoidable impurities, and cladding an Al-Si alloy brazing filler metal on the other side. Dexterous aluminum clad material. [Claim 2] Mn 0.3-1.5 wt%, Cu
0.2-0.9 wt%, Mg 0.2-0.5wt
%, Si 0.2-1.0wt%, Fe 0.10
~0.7 wt%, Ti 0.10 ~0.3 wt%
and further contains Zr 0.05 to 0.2 wt%, C
Zn 0.3 to 2.0 wt%, on one side of an aluminum alloy core material containing one or two of r 0.05 to 0.2 wt%, with the remainder being Al and unavoidable impurities.
A heat treatment material characterized in that it is clad with an aluminum alloy skin material containing 0.2 to 1.0 wt% Mg and the remainder consisting of Al and unavoidable impurities, and the other side is clad with an Al-Si alloy brazing material. Aluminum cladding material for exchangers.