JPH01198453A - Manufacture of high electric conductive aluminum alloy fin material - Google Patents

Abstract

PURPOSE:To obtain a fin material having excellent sagging resistance at the time of brazing and having high heat conductivity by cladding an Al-Mn alloy as the core and an Al alloy to which Fe and Zr are added as the surface material and specifying the rolling conditions including a heat treatment and intermediate annealing. CONSTITUTION:The Al alloy surface material contg., by weight, one or two kinds of 0.03-0.7% Fe and 0.03-0.35% Zr is clad on the both surfaces of the core of the Al-Mn alloy contg. 0.6-2.0wt.% Mn. It is subjected to a homogeneous treatment at 430-530 deg.C and the clad material is hot-rolled. The material is thereafter subjected to intermediate annealing at least for one time and is subjected to cold-rolling at 5-60% rolling ratio from the final intermediate annealing to the final plate thickness. The temp. of the intermediate annealing is preferably regulated to about >=380 deg.C. By this method, the Al alloy fin material having excellent sagging resistance and high temp. buckling resistance and having high heat conductivity can be obtd.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a method for manufacturing an aluminum alloy fin material for a heat exchanger that is joined by brazing, and more specifically, an aluminum alloy fin material that exhibits excellent sagging resistance during brazing heat and that The present invention relates to a method of manufacturing an aluminum alloy fin material having high thermal conductivity suitable for improving the heat exchange coefficient (cooling efficiency) of a heat exchanger.

(Prior art) Aluminum alloy heat exchangers, which are generally assembled by brazing, consist of passages (hereinafter referred to as tubes) through which a refrigerant such as water passes, and fins that dissipate heat. Depending on the application, extruded flat multi-hole tube or A
Press-molded plates made of plating sheets clad with 1-5i brazing filler metal as a skin material and electric resistance welded flat tubes are used. Further, as the fin material, a plating sheet in which both surfaces of a core material 1 are clad with a skin material 2, as shown in FIG. 1, or a bare fin material (bare material) without cladding the skin material is used.

A concrete example of a brazed aluminum alloy heat exchanger is shown in FIGS. 2 and 3. FIG. 2 shows a Doron cup evaporator, in which press-formed plates 3 made of plating sheets are stacked to form a tube, to which corrugated fins 4 made of bare material are combined. FIG. 3(A) shows a serpentine evaporator, which is a combination of an extruded flat multi-hole tube 13 and a corrugated fin 14 made of a play sink sheet, and FIG. The figure (c) shows the radiator, and the electric resistance welded flat tube 33 is made of a plating sheet clad with AM-Si brazing material on one side (with wax on the outside of the tube). This is a combination of the fin material 34 made of bare wood and the fin material 34 made of bare wood. The tubes and corrugated fins of these heat exchangers are flux brazed at a temperature of approximately 600°C.
It is assembled by vacuum brazing or inert gas atmosphere brazing.

Conventionally, in aluminum alloy heat exchangers assembled by brazing, AJI-Mn alloys with good buckling resistance, such as 3003 alloy (Al
-0,05~0.20w t%Cu-1,0~1.5
wt%Mn alloy [hereinafter wt% is simply abbreviated as %]) or 3
203 alloy (Al-1.0-1.5% Mn alloy) and
In order to have a sacrificial effect on these, an alloy to which Zn, Sn, In, etc. are added is used as a core material, and AJI-Si is coated on both sides of the core material.
Alloy brazing filler metal (AfL-5-12% Si alloy), A! L-
Si-Mg alloy brazing filler metal (AfL-5~12%5i-0,
5-2% Mg alloy) etc. with a thickness of 0.1-0.
2-Lin plating sheet or thickness 0.1~0.21
Bare materials such as the 3003.3203 alloy are used for the blinds.

On the other hand, in recent years, heat exchangers, especially those for automobiles, have become lighter and more compact, and there is a need for thinner fins and improved heat exchanger performance, that is, improved heat exchange efficiency (cooling capacity). It's coming.

Therefore, it is desired to develop a fin material that does not deteriorate in high-temperature buckling resistance even when thinned and has excellent thermal conductivity.

(Invention or problem to be solved) However, A like 3003 alloy and 3203 alloy
Although fin materials made of l -M n-based alloys have excellent buckling resistance, they do not necessarily have high thermal conductivity, and this is the cause of poor heat dissipation in heat exchangers using this fin material. Ta.

In addition, fin materials made of alloys with compositions close to pure aluminum have been proposed in recent years to improve thermal conductivity, but such alloys have low high-temperature strength, poor sagging resistance, and are difficult to braze. The fins tend to deform when heated, making it difficult to reduce the thickness.

Therefore, the object of the present invention is to provide a method for producing an aluminum alloy fin material that can be thinned, has excellent sagging resistance during brazing heat addition, has high thermal conductivity, and can improve the thermal efficiency of a heat exchanger. It is about providing.

(Means for Solving the Problems) As a result of intensive research to solve the problems of the conventional technology, the present inventors have developed a core material made of Al-Mn alloy and made of Fe.
, an aluminum alloy fin material clad with A1 alloy as a skin material to which a predetermined amount of Zr has been added meets the above objectives, and in manufacturing this fin material, the rolling treatment conditions including soaking treatment and intermediate annealing are suitable for sagging resistance. The present invention was completed based on the discovery that this has a significant influence.

That is, in the present invention, the essential components are rcMno, 6 to 2.
FeO, 03-0.7% and Zr0.03 as essential components on both sides of the core material of Al-Mn alloy containing 0%
When manufacturing a fin material by hot rolling and cold rolling a composite material made by cladding A1 alloy skin material containing ~0.35% of one or two types, at a temperature of -430 to 530 ° C. After performing soaking treatment, the laminated material is hot rolled, then intermediate annealing is performed at least once, and cold rolling is performed from the last intermediate annealing to the final plate thickness at a rolling rate of 15 to 60%. The present invention provides a method for manufacturing a highly thermally conductive aluminum alloy fin material.

(Function) The function of each component in the core material and skin material of the aluminum alloy fin material of the present invention and the reason for limiting the content will be described below.

The Mn content of the aluminum alloy used as the core material of the fin material of the present invention is 0.6 to 2.0%. Mn improves the strength of the aluminum alloy, produces precipitates of the A-Mn system, the A-Mn-Fe system, or the AM-Mn-Si system, and improves the sagging resistance during brazing heat. M
If the n content is less than 0.6%, the effect is small; 2.
If it exceeds 0%, giant crystallized substances are likely to occur, resulting in poor formability as a fin material.

In addition to Mn, the aluminum alloy used as the core material of the fin material of the present invention contains 0.8% or less of Fe, Ni, 0.6%
% or less of Si, 0.5% or less of Cu, and 0.3% or less of Zr. These elements further improve the sag resistance. In addition, 6 is 0 for refining the ingot structure.
．． It may contain less than 1% Ti or B. Furthermore, 2.0% or less Zn and 0.1% or less Sn
or In can be added as a fin material to provide the necessary sacrificial anode effect.

The Fe content of the aluminum alloy used as the skin material of the fin material of the present invention is 0.03 to 0.7%. Fe increases the high temperature strength of the skin material and has the effect of not reducing the high temperature buckling resistance of the fin material as a whole. Fe content is 0.0
If it is less than 3%, its effect will not be sufficient, and if it exceeds 0.7%, the thermal conductivity will decrease.

The Zr content of the aluminum alloy used as the skin material of the fin material of the present invention is 0.03 to 0.35%. Z
r significantly improves the sag resistance without impairing the thermal conductivity of the alloy.

If it is less than 0.03%, its effect is not sufficient, and 0.35%
If it exceeds this amount, Al-Zr crystallized substances will be produced, resulting in poor formability as a fin material. In addition, the skin material containing 2
E may be contained up to 0.7%.

The aluminum uneven alloy used as the skin material in the present invention contains Fe or Zr, and in addition to Fe and Zr, 0.05% or less of Ti and B are added to refine the ingot structure and to provide a sacrificial anode effect. 0.1% or less of Sn or In or 0.1% or less.
6% or less Zn, 0.3% to improve sagging resistance
% or less of Cu, and 0.6% or less of Si or Mn, respectively. However, since these elements reduce the thermal conductivity of the fin material, it is desirable that the amount thereof be as small as possible.

The fin material of the present invention is made by cratting a core material and a skin material having the above composition, and in this case, the cratting ratio is 5 to 3 per side.
0% is preferred. The aluminum alloy fin material of the present invention improves thermal conductivity by cladding a core material with excellent droop resistance and high-temperature strength with a skin material with good thermal conductivity. If the thermal conductivity is not sufficiently improved and it exceeds 30%, the proportion of the core material decreases, resulting in insufficient high temperature strength.

Next, each step in the method for manufacturing an aluminum alloy fin material of the present invention will be explained.

First, in the present invention, 430 to 530
A soaking treatment is performed at ℃ for 1 to 24 hours. The soaking treatment can reduce segregation of the ingot and allow Mn, which is dissolved in solid solution during casting, to precipitate as a Mn-based compound. In addition, when the skin material contains Zr, the solid solution of Zr is precipitated as fine particles through soaking treatment, increasing the high-temperature strength of the skin material and improving the sagging resistance of the fin material as a whole. The above effect is not sufficient if the temperature is less than 430℃ or the time is less than 1 hour, and the temperature is less than 5"30℃.
If the time exceeds 24 hours or exceeds 24 hours, Mn-based precipitates become coarse and the sagging resistance and high-temperature strength of the fin material decrease. In the present invention, the soaking treatment may be performed before the cladding step, or may also be performed after the cladding step and before hot rolling.

Hot rolling can be carried out in a conventional manner.

In the method of the present invention, intermediate annealing is performed at least once to reduce the hot rolled diameter, and from the final intermediate annealing to the final plate thickness, the thickness is 15 to 60 mm.
Cold rolling is performed at a rolling rate of %. If recrystallization is not completed during intermediate annealing, the sagging resistance will deteriorate, so the intermediate annealing temperature should be set to 3.
Preferably, the temperature is 80°C or higher. In addition, the final rolling ratio is 15 to 60.
% is determined because if it is less than 15%, the recrystallization of the fin material will not be completed during brazing heating, and in such a case, the sagging resistance will decrease, and if it exceeds 60%, the recrystallized grains during brazing will be fine. This is because the high temperature strength decreases.

(Example) Next, the present invention will be explained in more detail based on examples.

The fin material shown in FIG. 1 was prepared using the core material and skin material of an aluminum alloy having the composition shown in Table 1 and the cladding ratio shown in the same table. In FIG. 1, numeral 1 is a core material, and 2 is a skin material. The fin material was produced according to the steps shown in Table 2. The soaking treatment before hot rolling was carried out before the cladding process, but some of the fin materials were carried out after the cladding process. 30 for hot rolling
It was carried out at 0 to 530°C, and the final plate thickness was 3.5 sm.

After hot rolling, final plate thickness is 0.10 by annealing and cold rolling.
A fin material of mm shown in FIG. 1 was obtained. The fin material sample obtained in this manner was used as a corrugated fin, and a Dron cup evaporator shown in FIG. 2 was prototyped using this.

In FIG. 2, numeral 3 is a press plate, and 4 is a corrugated fin. Press plate 3 has core material 300
3 alloy, brazing material 4004 alloy (clad ratio 15% on both sides)
A plating sheet with a thickness of 0.6 mm was used. The width of the fin 4 was 1 ooll, and the vacuum brazing method was used for brazing. The sagging resistance of the obtained fin material, the cooling efficiency of the evaporator, and the buckling resistance of the fin were measured. The test method and judgment method are as follows. The results are shown in Table 3.

■Cooling capacity test JIS D 1618 (automobile air conditioner test method)
I followed the instructions.

■ Drooping test A sample piece of fin material with a width of 22 mm and a length of 60 mm was cut out, one end was protruded 50 m, and the other end was fixed in a cantilevered state. After heating at 610°C for 10 minutes, the front end of the protrusion was suspended. The amount (+s■) was measured. Materials that sag less have better sagging resistance.

■Buckling Resistance Test When manufacturing the Doron cup evaporator shown in Figure 2, it is assumed that there will be no poor brazing between the fins and the press plate due to buckling of the fins during brazing. Compare the song 1O-1) after wax hammering and find the decrease of 0.3-1 or less in Table 3 (Note) Cooling capacity is the improvement (or decrease) rate based on No. 11 Table 3 As is clear from the results, the aluminum alloy fin materials (Nos. 1 to 5) according to the present invention have excellent drooping resistance and good buckling resistance as corrugated fins for evaporators, and also have excellent cooling capacity of evaporators. Conventional evaporator (No.

11) It has higher thermal conductivity than that of 11). On the other hand, the comparative examples (Nos. 6 to 10) had poor droop resistance and could not be assembled into an evaporator, and even if they were barely assembled, they had poor buckling resistance and reduced cooling capacity.

(Effects of the Invention) According to the present invention, an aluminum alloy fin material having excellent droop resistance and high-temperature buckling property and high thermal conductivity can be obtained. Therefore, by using the aluminum alloy fin material according to the present invention, it is possible to manufacture a heat exchanger that has excellent heat dissipation characteristics and is smaller and lighter in weight.

[Brief explanation of the drawing]

Figure 1 is a sectional view of the fin plating sheet, Figure 2 is a side view of the Dron cup evaporator, and Figure 3 (
Figure (a) is a perspective view of the evaporator, figure (b) is a perspective view of the capacitor, and figure (c) is a side view (partially cut away) of the radiator. Explanation of symbols l...Core material 2...Skin material 3...Press plate 4...Corrugate fin Patent applicant Furukawa Aluminum Industries Co., Ltd. Agent Patent attorney Ii 1) Toshizo, 1.1.1 ) Figure 1 Figure 2
Figure 3 (...)

Claims (1)

[Claims] Fe as an essential component is added to both sides of the core material of an Al-Mn alloy containing 0.6 to 2.0 wt% of Mn as an essential component.
0.03-0.7wt% and Zr0.03-0.35
When producing a fin material by hot rolling and cold rolling a composite material made of a clad Al alloy skin material containing one or two types of wt%, a soaking treatment is performed at a temperature of 430 to 530 ° C. After that, the laminated material is hot rolled, then intermediate annealing is performed at least once, and cold rolling is performed at a rolling rate of 15 to 60% from the last intermediate annealing to the final plate thickness. Method for manufacturing aluminum alloy fin material.