JP3222577B2 - Aluminum alloy fin material for heat exchanger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy fin material for a heat exchanger having a high thermal conductivity, and more particularly to a radiator and a heater which are heat exchangers for automobiles manufactured by a brazing method. And aluminum alloy fin materials used as fins for condensers and the like.

[0002]

2. Description of the Related Art Most heat exchangers for automobiles use Al and Al alloys and are manufactured by a brazing method. Usually, Al-Si-based brazing material is used for brazing, so brazing is performed at a high temperature of about 600 ° C. As shown in FIG. 1, for example, a heat exchanger such as a radiator is formed by integrally forming a corrugated thin fin (2) between a plurality of flat tubes (1).
Both ends of (1) are open to the space formed by the header (3) and the tank (4), and the high-temperature refrigerant flows from the space on one tank side through the flat tube (1) to the other tank.
The refrigerant is sent to the space on the side of (4), and the refrigerant cooled down by heat exchange between the flat tube (1) and the thin fin (2) is circulated again.

In recent years, heat exchangers are becoming lighter and smaller, and for that purpose, it is necessary to improve the heat efficiency of the heat exchanger, and it is desired to improve the heat conductivity of the material. In particular, improvement in the thermal conductivity of the fin material is being studied, and an alloy fin material having an alloy composition closer to pure aluminum has been proposed as a high heat conductive fin. However, when the fins are thinned, if the fins are not strong enough, there is a problem that the fins are crushed when the heat exchanger is assembled, or broken when used as a heat exchanger. Pure aluminum alloy fins have the disadvantage of insufficient strength, and fin materials with high strength and improved thermal conductivity have not yet been developed. This is because the addition of an alloy element such as Mn is effective in increasing the strength, but since there is brazing that is heated to around 600 ° C. in the process of manufacturing the heat exchanger, it is added to the alloy during brazing heating. This is because the element re-dissolves and hinders improvement in thermal conductivity.

[0004]

In view of this, the present inventors have developed a fin material having high strength after brazing and high thermal conductivity by adjusting the amounts of Si and Fe to improve the thermal conductivity. The present invention was deemed to be able to solve the problem by finding an alloy element having a large effect of improving strength without further lowering the thermal conductivity, and reached the present invention. That is, the present invention has developed an aluminum alloy fin material for a heat exchanger having excellent heat conductivity and strength after brazing.
Si more than 0.2wt% and less than 0.8wt%, 0.03wt%
Over 0.4 wt% Fe, over 0.1 wt% 1.2
An aluminum alloy fin material for a heat exchanger, characterized by containing Co of not more than wt% and the balance consisting of Al and unavoidable impurities. % Of Si, more than 0.03 wt% and 0.4
Fe of less than wt%, C of more than 0.1 wt% and less than 1.2 wt%
o, and Zn of not more than 2.0 wt%, 0.3 wt%
An aluminum alloy fin material for a heat exchanger, characterized by containing one or more of the following In and Sn of 0.3 wt% or less, and the balance consisting of Al and unavoidable impurities.

[0005]

The role of the additional elements in the fin material of the present invention and the reasons for limiting the alloy composition will be described. Si improves the strength and improves the thermal conductivity by its addition. In particular, Fe
When coexisting with Co or Co, it has an action of accelerating the precipitation of Fe or Co, so that the amount of intermetallic compounds contributing to dispersion strengthening is increased and the strength is improved. Further, since the precipitation of Fe and Co is promoted to reduce the amount of Fe and Co dissolved in the fin material, the thermal conductivity is improved.
When the content of Si is 0.2 wt% or less, the above effect is not sufficient,
If it exceeds 0.8% by weight, the diffusion of the brazing during brazing heating becomes large, and the brazing property decreases. Therefore, the content of Si is set to be more than 0.2 wt% and 0.8 wt% or less, but in particular, 0.3 wt% or less.
It shows stable characteristics at 0.6 wt%.

[0006] Fe forms an intermetallic compound with Si and contributes to improvement in strength. If the amount is less than 0.03% by weight, there is no effect, and if it exceeds 0.4% by weight, the thermal conductivity decreases.

[0007] Co disperses fine intermetallic compounds in the alloy to improve the strength. When added together with Si, it is an element that can be very easily precipitated, so that the strength can be improved without lowering the thermal conductivity.
If the amount is less than 0.1 wt%, the effect is not sufficient,
If it is added in excess of wt%, the moldability will be reduced, and it will be difficult to form corrugated fins.

In the alloy of the present invention, the Z content of 2.0 wt% or less
One or two or more of n, 0.3 wt% or less of In, and 0.3 wt% or less of Sn may be added. These are added to impart a sacrificial anode effect to the fin material, and when added in amounts exceeding the above amounts, the thermal conductivity is reduced.

As inevitable impurities of the alloy of the present invention, there are Ti and B added for refining the ingot structure, and these elements may be added as long as each of these elements is 0.03% or less. Absent.

Although the above is the alloy composition of the present invention, the fin material of the present invention can be used as a bare material,
Further, it can be used as a core material of a brazing sheet fin. In the latter case, a conventionally used brazing alloy may be used as it is.

The heat exchanger using the fin material of the present invention includes, but is not limited to, a radiator, a condenser, an evaporator, an oil cooler and the like for automobiles.

Further, the method of brazing the fin material of the present invention can be any of conventional non-corrosive flux brazing, flux brazing, vacuum brazing and the like.

The fin material of the present invention can be produced by semi-continuous casting to produce an ingot, which can be produced in the steps of hot rolling, cold rolling and annealing, and continuous casting rolling, cold rolling and annealing. It can also be manufactured by the above process.

[0014]

The present invention will be specifically described below with reference to examples. An aluminum alloy fin material (plate thickness: 60 μm, H14 temper) having the composition shown in Table 1 was produced by a conventional method. The strength and conductivity of these fin materials after the heat of brazing were measured.
The condition of the brazing heat was 600 ° C. × 5 minutes in nitrogen gas. Table 2 shows the results. Here, the electrical conductivity is an index of thermal conductivity. When the electrical conductivity of the fin is improved by 5% IACS, the thermal efficiency of the heat exchanger is improved by about 1%.

[0015]

[Table 1]

[0016]

[Table 2]

As is clear from Table 2, the fin materials of the conventional example and the comparative example have no excellent tensile strength and electrical conductivity, whereas the fin material of the present invention has excellent tensile strength and electrical conductivity. It shows excellent values.

[0018]

As described above, the fin material of the present invention has high strength and excellent thermal conductivity, and has an industrially remarkable effect.

[Brief description of the drawings]

FIG. 1 is a perspective view of a partial cross section showing a radiator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flat tube 2 Thin fin 3 Header 4 Tank

Claims (2)

(57) [Claims] 1. S in excess of 0.2% by weight and 0.8% by weight or less
i, Fe of more than 0.03 wt% and less than 0.4 wt%, 0.1
An aluminum alloy fin material for a heat exchanger, characterized in that it contains more than 1.2 wt% of Co and more than 1.2 wt% of Co, with the balance being Al and unavoidable impurities. 2. An S content exceeding 0.2 wt% and not more than 0.8 wt%.
i, Fe of more than 0.03 wt% and less than 0.4 wt%, 0.1
It contains more than 1.2% by weight of Co and more than 1.2% by weight.
0 wt% or less Zn, 0.3 wt% or less In, 0.3 wt%
An aluminum alloy fin material for a heat exchanger, comprising one or more of the following Sns, the balance being Al and unavoidable impurities.