JPH04297541A - Aluminum alloy clad material for heat exchanger - Google Patents

Abstract

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

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy clad material for heat exchangers that has high strength and good brazing properties, and is particularly suitable as a tube material for aluminum radiators.

0002

[Prior Art] Conventionally, the tube material for aluminum radiators is JIS 3003 alloy (Al-0.1
5wt%Cu-1.1wt%Mn) is used as a core material, one side of which is clad with an Al-Si alloy brazing material, and the other side is clad with an Al-Zn alloy skin material. Using such a cladding material, Al-Zn
An electric resistance welded flat tube is used as a tube material for the above-mentioned radiator, with the alloy skin material side facing inside and the Al-Si alloy brazing material side facing outside. The outer Al-Si alloy brazing material is necessary for brazing with the aluminum fins, and the inner Al-Zn alloy skin material acts as a sacrificial anode material for the core material, and serves as a sacrificial anode material for the cooling water. This prevents corrosion of the tube material. In order to braze such tube materials and fin materials, so-called Nocolock brazing using fluoride-based flux has recently been frequently used.

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, the strength of aluminum materials has become necessary. Adding Mg to the core material is effective for improving this 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, which not only wastes flux but also causes niM
Forms a thin film of gF2, which impairs brazing properties. Therefore, a large amount of Mg cannot be added to the core material of the tube material.

0004

[Means for Solving the Problems] The present invention has been made in view of the above, and as a result of various studies, an aluminum alloy cladding material for heat exchangers has been developed which 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 0.10-0.3%, Fe 0.10-0.
Zn 0.3-2.0%, Mg 0.05 on one side of an aluminum alloy core material containing 7% Ti, 0.10-0.3% Ti, and the remainder Al and inevitable impurities.
~0.2%, 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.

Another cladding material of the present invention is Mn
0.3-1.5%, Cu 0.2-0.9%, Mg
0.2-0.5%, Si 0.10-0.3%
, Fe 0.10 ~ 0.7%, Ti 0.10 ~
Contains 0.3% and further contains Zr 0.05 to 0.2
%, Cr 0.05-0.2%, Zn 0.3-2.0%, M
It is characterized by being clad with an aluminum alloy skin material containing 0.05 to 0.2% g and the remainder consisting of Al and unavoidable impurities, and the other side being clad with an Al-Si alloy brazing material. be.

[0007]

[Function] The present invention is a cladding material consisting of a core material, skin material, and brazing material having the above composition, in which the amount of Mg contained in the core material is minimized to improve brazing properties, and the strength is increased. It is. 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 skin material side and reduces the Mg of the core material.
Decrease the amount of g and decrease the strength. Therefore, in order to suppress the diffusion to the skin material side, Mg may be added to the skin material in advance. Further, Si in the core material generates Mg2Si, which is an effective element for age hardening, but if too much, it impairs corrosivity. Since Si diffuses into the core material from the brazing material during brazing, it is sufficient to include less Si in the core material in advance.

[0008] The additive elements will be explained below. 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 will crystallize, so it is not preferred. do not have. Cu not only improves the strength, but also shifts the potential of the core material to the noble side and improves corrosion resistance, but if it is less than 0.2%, the effect is insufficient, and if it exceeds 0.9%, the resistance welding properties deteriorate. At the same time, corrosion resistance deteriorates. Mg is effective in improving strength, but if it is less than 0.2%, the effect is insufficient, and 0
．． If it exceeds 5%, brazing properties will deteriorate. Si coexists with Mg to precipitate Mg2Si and is effective in improving strength, but if it is less than 0.10%, the effect is insufficient, and 0.3%.
Exceeding this will deteriorate corrosion resistance. Fe works effectively during casting and electric resistance welded pipe manufacturing, making the structure fine and preventing cracking during solidification, but if it is less than 0.10%, the effect is insufficient;
If it exceeds 7%, coarse compounds are formed and corrosion resistance is also impaired. Ti is effective in improving corrosion resistance and slows down the progression of pitting corrosion, but if it is less than 0.10%, the effect is insufficient;
If it exceeds 0.3%, it is not preferable because coarse compounds are formed. Although the addition of Zr and Cr is effective in improving strength,
In either case, if it is less than 0.05%, the effect is insufficient, and 0
．． If it exceeds 2%, coarse compounds will be formed, which is not preferable.

[0009] Zn in the skin material is an essential component to make the skin material electrochemically less noble with respect to the core material and to form a sacrificial corrosion layer, and if it is less than 0.3%, the effect is weak; If it exceeds %, the effect will be saturated. Although Mg prevents Mg from diffusing from the core material to the skin material and prevents the strength of the core material from decreasing, 0.0
If it is less than 5%, the effect is insufficient, and if it exceeds 0.2%, the corrosion resistance of the skin material will be reduced.

On the other hand, Si in the brazing material diffuses into the core material during brazing to form Mg2Si, which is extremely effective in improving strength. In this case, the core material has Si in the range of 0.10 to 0.
．． Since it contains 3%, the strength is stabilized. As the brazing material, a normal Al--Si alloy brazing material may be used.

[0011]

[Examples] The present invention will be explained below with reference to Examples. Table 1
A three-layer cladding material consisting of a core material, a brazing material, and a sacrificial material (skin material) shown in Table 2 was prepared. The manufacturing method is the same as usual, with the core material being 40 mm thick, the brazing material being 5 mm thick, and the sacrificial material being 5 mm thick, and then hot rolling, cold rolling, and intermediate annealing to create a 0.3 mm thick plate ( Finished with clad material).

Then, as shown in FIG. 1, the plate material (1)
Place the filler metal sides facing each other, and place J between the plates (1).
A fin (2) made of IS 3003 alloy is arranged,
The outside of the plate material (1) was clamped with JIS 3003 alloy fins (3) for holding down, and fixed with a holding jig (4). Next, fluoride flux FL7 was applied to this, and after drying, it was heated to 600°C for 3 minutes in a nitrogen gas atmosphere to change the brazed state of the fins to the fin (2) and plate material (1).
The number of fillets that were successfully formed was investigated for 100 joints.

[0013] Regarding the above plate material, flux FL7 was applied to the brazing metal side, and after drying, it was heated to 600°C for 30 minutes in a nitrogen gas atmosphere, cooled at a rate of 100°C/min, and tensile strength was applied after one week. The test was conducted.

[0014] Also, from the heated and cooled plate material, 50 mm ×
Cut out a 50mm test piece, seal the brazing metal side, and
A corrosion resistance test was conducted by immersing the sample in water containing 100 ppm of u2+, heating it to 90° C. for 8 minutes, and then performing 90 cycles of cooling for 16 hours.

[0015] These results are shown in Table 3.

[0016]

[Table 1]

[0017]

[Table 2]

[0018]

[Table 3]

As is clear from Tables 1, 2 and 3,
It can be seen that the cladding material of the present invention has high strength, excellent brazing properties, and corrosion resistance. On the other hand, comparative claddings that differ from the composition of the cladding material of the present invention are inferior in strength, brazing properties, and corrosion resistance.

[0020]

[Effects of the Invention] As described above, according to the present invention, a heat exchanger,
In particular, it improves the strength, brazing properties, and corrosion resistance of aluminum alloy clad materials used as tube materials for radiators, and has significant industrial effects such as making it possible to reduce the weight of heat exchangers.

[Brief explanation of the drawing]

FIG. 1 is a side view showing the configuration of a brazing test in the present invention.

[Explanation of symbols]

1 Board material 2 Fin 3. Holding fins 4 Holding jig

Claims (2)

[Claims] [Claim 1] Mn 0.3-1.5 wt%, Cu
0.2-0.9 wt%, Mg 0.2-0.5wt
%, Si 0.10 ~ 0.3 wt%, Fe 0.1
0 ~ 0.7wt%, Ti0.10 ~ 0.3wt
Zn 0.3 to 2.0 wt.
%, Mg 0.05 to 0.2 wt%, and the balance is Al and inevitable impurities, and the other side is clad with an Al-Si alloy brazing material. Aluminum alloy cladding material for heat exchangers. [Claim 2] Mn 0.3-1.5 wt%, Cu
0.2-0.9 wt%, Mg 0.2-0.5wt
%, Si 0.10 ~ 0.3 wt%, Fe 0.1
0 ~ 0.7wt%, Ti0.10 ~ 0.3wt
%, and further contains Zr 0.05 to 0.2 wt%,
One side of an aluminum alloy core material containing one or two of 0.05 to 0.2 wt% of Cr, with the balance being Al and inevitable impurities, and 0.3 to 2.0 wt% of Zn.
, Mg 0.05 to 0.2 wt%, the balance being A
1. An aluminum alloy cladding material for a heat exchanger, characterized in that the aluminum alloy skin material is clad with aluminum alloy and inevitable impurities, and the other side is cladded with an Al-Si alloy brazing material.