JP3256910B2 - 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.
More than 0.3 wt% and less than 0.8 wt% Si, more than 0.5 wt% and less than 1.5 wt% Fe, more than 0.1 wt% and more than 2.0 wt%
% Ni or less, C exceeding 0.01 wt% and 2.0 wt% or less
An aluminum alloy fin material for a heat exchanger, characterized by comprising o and the balance being Al and unavoidable impurities.
% Of Si, 0.5% or more and 1.5% or less of F
e, Ni of not less than 0.1 wt% and not more than 2.0 wt%, 0.01
An aluminum alloy fin material for a heat exchanger, containing Co in an amount of more than 2.0% by weight and not more than 2.0% by weight of Zr, and Zr in an amount of more than 0.03% by weight and not more than 0.2% by weight. The invention according to claim 3 is 0.3
More than 0.8 wt% Si, more than 0.5 wt% and less than 1.5 wt% Fe, more than 0.1 wt% and less than 2.0 wt% Ni, more than 0.01 wt% and more than 2.0 wt% The following Co is contained, and further contains one or more of Zn of 2.0 wt% or less, In of 0.3 wt% or less, and Sn of 0.3 wt% or less, with the balance being Al and unavoidable impurities. An aluminum alloy fin material for a heat exchanger, characterized in that:
wt% or less Si, more than 0.5wt% and 1.5wt% or less F
e, Ni of not less than 0.1 wt% and not more than 2.0 wt%, 0.01
contains more than 2.0% by weight of Co, more than 0.03% by weight and less than 0.2% by weight of Zr, and further contains not more than 2.0% by weight of Zn, less than 0.3% by weight of In, and 0.3% by weight. The following Sn
Fin material for heat exchangers, characterized by containing one or more of the above, 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 by its addition. In addition to improving the strength by solid solution hardening of Si itself, especially when coexisting with Fe, Ni and Co, it has an effect of accelerating the precipitation of Fe, Ni and Co. Increase and improve strength. Further, Fe, Ni and Co
Of Fe dissolved in the fin material by promoting the precipitation of
And the amount of solid solution of Ni and Co is reduced, so that the thermal conductivity is improved. When the content of Si is 0.3 wt% or less, the above effect is not sufficient. When the content of Si exceeds 0.8 wt%, the diffusion of the brazing during brazing heating increases, and the brazing property is reduced. Accordingly, the content of Si is set to be more than 0.3 wt% and not more than 0.8 wt%, and particularly, it exhibits stable characteristics at more than 0.3 wt% and not more than 0.6 wt%.

[0006] Fe is solid-solution hardened by a certain amount in the alloy, and the rest exists as an intermetallic compound. The former improves the strength, but greatly reduces the thermal conductivity. The latter slightly improves the strength by dispersion strengthening, but has the effect of forming an intermetallic compound with Si and conversely reducing the strength improving effect of the addition of Si. Here, when the amount of Fe added is 0.5 wt% or less, the effect of improving the strength is not sufficient, and when it exceeds 1.5 wt%, the formability is reduced, and it becomes difficult to form corrugated fins.

[0007] Ni and Co are important additional elements in the present invention, as a result of intensive studies by the present inventors, and found that they have an effect of improving strength without lowering thermal conductivity. That is, Ni and Co improve the strength by solution hardening, but at the same time, Ni and Co
Has the effect of reducing the amount of Fe solid solution corresponding to the amount of solid solution of Fe. When Fe, Ni and Co form a solid solution, the effect of improving the strength is almost the same, but the decrease in thermal conductivity is much smaller in Ni and Co. Therefore, when Ni and Co are added to the alloy containing the Fe amount, the strength is improved without lowering the thermal conductivity. Here, the effect of Ni and Co is greater in Ni, but Co serves as a nucleus for the generation of an Fe-based intermetallic compound and has an effect of promoting the effect. Therefore, the effect is not sufficient if the addition amount of Ni is 0.1 wt% or less, but the effect is effective if the addition amount of Co exceeds 0.01 wt%. If both of them are added in excess of 2.0% by weight, the moldability decreases, and it becomes difficult to form corrugated fins.

[0008] In the alloy of the present invention, Zr may be further added in an amount of more than 0.03 wt% and 0.2 wt% or less. Zr
Has a function to coarsen recrystallized grains generated at the time of brazing, and to prevent dripping of the fins and diffusion of the brazing to the fins. If the addition is less than 0.03 wt%, the function is not sufficient. However, the present inventors have examined and found that Zr has almost no function of improving the strength and is an element that lowers the thermal conductivity, so that the upper limit of the addition is set to 0.2 wt%.

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.

The inevitable impurities of the present alloy and elements added for reasons other than the above include Ti and B which are added for refining the ingot structure. If it is not more than 03 wt%, it may be added. Also, Cu, Mn, Mg, Na, Cd, P
When elements such as b, Bi, Ca, Li, Cr, K, and V are added for the purpose of improving strength, preventing ingot cracking, improving formability, etc., the essential condition is 0.03 wt% or less. All of these elements reduce the thermal conductivity when added.

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 and rolling, cold rolling and annealing. It can also be manufactured by the above process.

[0015]

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

[0016]

[Table 1]

[0017]

[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.

[0019]

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 partially sectional perspective view showing a radiator.

[Explanation of symbols]

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

Claims (4)

(57) [Claims] 1. S in excess of 0.3% by weight and 0.8% by weight or less
i, more than 0.5 wt% and less than 1.5 wt% Fe, 0.1 wt%
An aluminum alloy fin material for a heat exchanger, characterized by containing more than 2.0% by weight of Ni and more than 0.01% by weight and less than 2.0% by weight of Co, with the balance being Al and inevitable impurities. 2. An amount of S exceeding 0.3 wt% and 0.8 wt% or less.
i, more than 0.5 wt% and less than 1.5 wt% Fe, 0.1 wt%
% To 2.0 wt% Ni, 0.01 wt% to 2.0 wt% Co, 0.03 wt% to 0.2 wt%
An aluminum alloy fin material for a heat exchanger, comprising the following Zr, the balance being Al and unavoidable impurities. 3. The amount of S exceeding 0.3 wt% and 0.8 wt% or less.
i, more than 0.5 wt% and less than 1.5 wt% Fe, 0.1 wt%
%, More than 2.0% by weight of Ni, more than 0.01% by weight and less than 2.0% by weight of Co, more than 2.0% by weight of Zn, less than 0.3% by weight of In, less than 0.3% by weight Sn
An aluminum alloy fin material for heat exchangers, characterized in that it contains one or more of the above, and the balance consists of Al and inevitable impurities. 4. The amount of S exceeding 0.3 wt% and 0.8 wt% or less.
i, more than 0.5 wt% and less than 1.5 wt% Fe, 0.1 wt%
% To 2.0 wt% Ni, 0.01 wt% to 2.0 wt% Co, 0.03 wt% to 0.2 wt%
The following Zr is contained, and further, Zn of 2.0 wt% or less,
An aluminum alloy fin material for a heat exchanger, comprising one or two or more of 0.3 wt% or less of In and 0.3 wt% or less of Sn, the balance being Al and unavoidable impurities.