JPS61261483A - Aluminum fin material for heat exchanger - Google Patents

Abstract

PURPOSE:To improve the hydrophilic property, corrosion resistance and press formability of an Al plate contg. prescribed percentages of Zn, Mn, Ga and Ti by forming a specified film on the Al plate. CONSTITUTION:A hardened film is formed on an Al plate having a chromate film contg. 3-30mg/m<2> Cr to obtain an l fin material for a heat exchanger. The Al plate is composed of, by wt%, 0.04-0.1% Zn, 0.1-0.5% Mn, 0.002-0.03% Ga, 0.02-0.15% Ti and the balance Al. The hardened film has 0.03-1.5mum thickness and is made of a composition consisting of an alkali silicate and a hydrophilic high-molecular compound.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to an aluminum fin material for a heat exchanger, and particularly to an aluminum fin material for a heat exchanger that is hydrophilic and has excellent corrosion resistance and press formability. The present invention relates to an aluminum plate material made of an aluminum alloy with a specific alloy composition that can be provided.

(Prior art and its problems) Fins made of aluminum or aluminum alloys have traditionally been used in the heat exchange parts of air conditioning equipment. When the temperature drops below the dew point, condensed water begins to adhere. Then,
The adhesion of water droplets causes an increase in ventilation resistance to the flow of air to be blown to the evaporator, which reduces the amount of ventilation throughout the evaporator and reduces heat exchange efficiency.

Therefore, in order to secure the necessary ventilation volume, the evaporator must be made large, but recently, miniaturization has been progressing from the viewpoint of resource saving, energy saving, and design, and the fin pitch of finned tube heat exchangers has been reduced. The reality is that the scope is also being narrowed down. If the fin pinch is narrowed due to such miniaturization, the above-mentioned phenomenon will become even more noticeable.

At this time, if the water wettability of the fin surface is made good, the condensed water will flow along the fin surface and will not become water droplets.
Therefore, an increase in ventilation resistance can be effectively suppressed, and a decrease in the amount of ventilation can also be prevented, thereby effectively suppressing a decrease in heat exchange efficiency.

On the other hand, if it is operated as an evaporator and the fin surface is left wet with water, the aluminum of the fin material will not dissolve due to air pollutants slightly dissolved in the water and Cu ions generated from the cooling pipe. It starts to come out. However, in this state, since the solution in which aluminum is dissolved is also in a substantially neutral region, the solubility of Al ions is low and a precipitate is formed as a hydrated oxide: A j (OH) 3 .

When this becomes dry, it turns into "white powder" and is scattered outside the air conditioner with the air blowing, causing indoor pollution problems.

For this reason, aluminum fins whose surfaces are coated with a surface treatment film have generally been used as fins for heat exchangers in view of heat exchange efficiency and rust prevention.

By the way, this surface treatment film is created by molding an aluminum material into a fin of the desired shape and combining it with a tube.
Most of the heat exchangers are formed by post-coating treatment after being made into heat exchangers.
), the boehmite method (Japanese Unexamined Patent Publication No. 53-14450), the alkali silicate method (Kiken 1981-48177), the chromate method, etc. have been proposed. However, these post-coating methods have in common: (1) the fin shape and fin pitch are restricted from the viewpoint of processing workability; and (2) the complex shape of the heat exchanger is (3) There is a risk of poor appearance and decreased heat exchange efficiency due to the formation of liquid pools; (4) It is difficult to carry out treatment liquid due to the combination of different materials. There are inherent issues such as an increase in pollution load and cost increase due to the large number of plants.

Therefore, as an alternative to such post-coat treatment, a pre-coat method has been proposed in which a surface treatment film is formed before forming the fin. According to this method, a film having uniform and good water wettability and excellent corrosion resistance is formed on the fin material when it is in a strip state, and the fin material having such a film can be shaped into the desired shape. fins will be processed.

The surface treatment film obtained by such a pre-coating method is highly hydrophilic, has excellent press formability, such as stretching, drawing, punching, ironing, flaring, etc., and has excellent corrosion resistance. In order to be superior, the desired coating must be formed uniformly, in a short time, and at low cost during the treatment process, and for this purpose aluminum materials (plates) must have excellent surface treatment properties. It is necessary to be there.

However, the aluminum plate (strip) on which a hydrophilic surface treatment film is formed by such a pre-coating method is subjected to degreasing and slight etching treatment in advance of the hydrophilic treatment. Usually, this treatment is carried out using a weakly alkaline treatment bath, and achieving a uniform finish is an essential condition for producing the next dense film.

On the other hand, one of the present inventors previously discovered that a material that has good thermal conductivity, which is necessary for a fin material, has excellent moldability into fins, and is also excellent in corrosion resistance. Aj
! -Mn-Ti-B-Be alloy was developed and filed as Japanese Patent Application No. 58-4393 (Japanese Unexamined Patent Publication No. 59-129747), but this alloy was made into H2S material using the normal manufacturing process. In some cases, it has become clear that about 20 to 40 oxide films are formed on the surface, which occludes residues of rolling oil. Since this oxide film has considerable resistance (durability) to degreasing liquid, it not only prolongs the degreasing process time, but also increases the degreasing and etching process due to the influence of rolling oil. It became clear that the treatment was not uniform, and it became clear that further improvements were needed in terms of surface treatment properties.

(Structure of the Invention) The present invention has been made against the background of the above, and its feature is that an alkali silica film is added on top of the chemical conversion film formed on the surface of the aluminum plate material. An aluminum fin material for a heat exchanger on which a cured film of a composite composition consisting of an acid salt and a hydrophilic polymer compound is formed, and the aluminum plate material has a weight of:
0.04-0.10% Zn, 0.1-0.5
% Mn, 0.002-0.03% Ga and 0.02
The aluminum alloy is composed of an aluminum alloy containing ~0.15% Ti, which improves the surface treatment properties of the aluminum plate and forms an effective chemical conversion coating on it, as well as hydrophilic hardening. This made it possible to form a film, thereby creating an aluminum fin material for heat exchangers with excellent hydrophilicity, corrosion resistance, and press formability.

In addition, such an aluminum plate material contains Zn in the above proportion,
Together with Mn, Qa and Ti, further by weight, 0,0000
5~o, o o o s% of B and 0.0001~0
．． By forming the fin from an aluminum alloy containing 0.02% Be, the press formability and quality of the fin material can be further improved. In addition, in the aluminum fin material for a heat exchanger according to the present invention, the chemical conversion film formed on the surface of the aluminum plate material is essential for improving the water resistance of a predetermined cured film formed thereon, Usually 3-30mg
A chromate film containing Cr of /d, especially a phosphoric acid chromate film, is formed on the degreased and etched surface of the aluminum plate. Further, a predetermined cured film formed on such a chemical conversion film has hydrophilic properties, and generally has a thickness of 0.03 to 1.5 μm.
It will be provided at a thickness of .

(Specific explanation of the structure) By the way, the aluminum alloy constituting the aluminum plate material used in the present invention contains a specific amount of Zn,
It contains Mn, Ga, and Ti, among which Mn (a) increases the recrystallization softening temperature of the resulting alloy, (b) increases material strength, and (c) improves formability during ironing. Ti is also an element that has the effect of refining the crystal grains of the ingot, and its grain refining effect improves the properties of the rolled sheet. This has the effect of making it uniform and thereby suppressing the occurrence of local defects during molding. In addition, in order to enjoy the maximum effect of adding these elements, it is necessary to add Mn within the range of 0.1 to 0.5% (based on weight; the same applies hereinafter). Ti must be added in a proportion of 0.02 to 0.15%, and this ensures that the material has good thermal conductivity, which is necessary for the fin material, and also has good formability into fins. This makes it possible to impart properties that are excellent in both corrosion resistance and corrosion resistance.

When Zn and Ga are further added as alloy components to an aluminum alloy together with Mn and Ti, the previously applied AIl-Mn-Ti-B-Be
Surface films such as oxide films formed on the surface of alloy plates can be made thinner, and the surface becomes unstable and active, increasing its reactivity to degreasing fluids, thereby preventing it from containing dirt. This has the effect that the oxidized film can be dissolved and removed in a short time. In addition, in the case of the Al1-Mn-Ti-Zn-Ga alloy according to the present invention, the degreasing liquid is strongly alkaline to weakly alkaline to neutral;
Furthermore, regardless of the acidity, the A12 surface film state is Z.
n, Aj without adding Ga! It was discovered that the metal is in a less noble state than the alloy, the reaction proceeds rapidly, and the treated surface becomes uniform.

When a chemical conversion film, usually a chromate film, especially a phosphoric acid chromate film is formed on the surface that has been degreased and etched in this way, with a solution consisting of chromic acid, phosphoric acid, and hydrofluoric acid, such a chromate film is formed. Experiments conducted by the present inventors have revealed that this method is effective in uniformizing and densifying chemical conversion coatings, such as coatings, and shortening processing time. This is because the surface film containing dirt is AI.
It is speculated that this is because it has been completely removed from the surface of the plate material and that the reaction of the alloy itself is enhanced in the acidic bath. As a result, degreasing, etching, and chemical conversion treatment can advantageously be carried out continuously on the Al plate material in the coiled state.

Regarding the amounts of Zn and Ga added that produce such excellent effects, Zn becomes sufficiently noble in potential when added up to 0.1%, and warps when Zn exceeds 0.1%. Although addition is effective for surface treatment,
The amount of dissolution reaction increases, making it difficult to manage the treatment solution, making it ineffective.

On the other hand, if the amount of Zn added is less than 0.04%, unstable
It becomes difficult to obtain an active oxide film state.

Therefore, the amount of Zn added is 0.04 to 0.1
It will be selected within the range of %.

Furthermore, when Zn is added within this range, if about 20 ppm of Ga is further added, A1
The state of the surface film is clearly sufficiently circular, and on the other hand, when the amount of Ga added exceeds 300 ppm, such a base state becomes even more obvious.
Since the amount of dissolution reaction becomes too large, addition of such a large amount of Ga is not as effective as the above-mentioned case where a large amount of Zn is added. Therefore, G
The amount of a added must be selected within the range of 0.002 to 0.03%.

Note that Ca, Sn, In, ca, and the like are known as metal elements that provide effects similar to those of Zn and Ga. In the present invention, adding these elements in place of Zn and Ga or in combination can provide the same effect, but
From the viewpoint of solubility in Al, toxicity of metal, etc., Zn
, Ga are preferable because they are easier to handle than these elements.

Furthermore, in this Af-Zn-Mn-Ga-Ti alloy, o, o o o o s to o, o o o s%
By adding B and 0.0001 to 0.002% of Be, it is possible to contribute to improving the formability and quality of the Al plate material, with almost no effect on the etching properties. In other words, B, together with Ti, has the effect of promoting refinement of the crystal grains of the ingot, thereby contributing to formability, but if the amount added is too large, it may cause coarse T i B It is desirable to add B in a proportion of 0.0005% or less since the compound is generated and warps and the moldability is deteriorated. In addition, Be has the effect of preventing oxidation during molten alloy, and by suppressing the formation of AItos as a harmful inclusion in the molten alloy as much as possible, it improves the quality of the sheet material, and ultimately improves the quality of the sheet material. This contributes to improving moldability. Furthermore, even if the amount of Be added is increased, no commensurate effect can be expected;
Such Be is o.

It is desirable to add within a range of up to 0.02%.

The aluminum alloy having such an alloy composition is then sequentially passed through the steps of ingot-forming, homogenization, hot rolling, cold rolling, and annealing in accordance with conventional methods, and is made into an aluminum thin plate. It is used as an aluminum plate material for manufacturing dexterous aluminum fin materials.

In addition, aluminum plates (thin plates) made of such specific aluminum alloys are treated with the following methods to remove rolling oil adhered to them during the processing process and oxide films formed on their surfaces.
Degreasing and etching treatment will be performed according to conventional methods, but as detailed above, since the aluminum plate material is made of a specific alloy system, such degreasing and etching treatment is not effective. The treatment can be applied uniformly, and the processing time can be effectively shortened.

The degreased and etched aluminum plate material is then subjected to a normal chemical conversion treatment to form a predetermined base film (chemical conversion film) on its surface. Furthermore, it has great significance in effectively forming a cured film, which will be described later, thereon. However, if the cured film layer does not exist on a uniform chemical conversion film, the cured film layer alone will not have sufficient water resistance, and the cured film layer will cause a decrease in cloudiness even in repeated dry-wet tests, resulting in obvious This is because it was recognized that the material showed significant deterioration. Note that this chemical conversion film is usually formed as a uniform phosphoromate film on the surface of the aluminum plate material.

In addition, this chromate film generally has a weight of 3 to 30 mg
It is desirable to contain Cr of /rd, and the Cr
If the content is less than 3 mg/rd, it becomes difficult to form a uniform film, and holes may occur in the film.

On the other hand, if the Cr content exceeds 30 mg/m2, it will have a negative effect on press formability and cause problems such as peeling in the chromate film layer.

Next, when the aluminum plate material on which the chemical conversion film, especially the uniform and dense phosphoric acid chromate film was formed, was made into a fin by imparting hydrophilicity to it, it had a 74%
．． In order to improve the water wettability of the surface of 7, a cured resin layer (cured film) of a predetermined thickness is formed using a hydrophilic polymer resin composition containing an alkali silicate. The composition for forming the cured film covering the surface of the aluminum plate is a film-forming composite composition containing an alkali silicate as the first component and a hydrophilic polymer compound as the second component. Further, such a composite composition is generally crosslinked and cured using a suitable crosslinking agent.

The alkali silicate, which is the first component constituting such a composite composition, usually provides a film-forming composition known as water glass, and generally has the formula: Me, C1n.
5iOz·aq (Me means lithium, potassium, sodium or amine). Further, the hydrophilic polymer compound serving as the second component has at least one polar group selected from a carboxyl group, a hydroxyl group, and an amino group, and includes, for example, acrylamide, methacrylamide, hydroxymethyl (meth)acrylamide, and hydroxyl group. (Meth)acrylamide such as ethyl (meth)acrylamide; hydroxypropyl (meth)acrylate, hydroxyethyl (
(Meth)acrylates such as meth)acrylate; polymers of unsaturated carboxylic acids such as acrylic acid and methacrylic acid, or copolymers of these unsaturated compounds, or these unsaturated compounds and other unsaturated compounds Examples include polymers made hydrophilic by introducing the carboxyl group, hydroxyl group, amino group, etc. by copolymerization with or hydrolysis, among which polymers that are water-soluble are preferred. It will be used.

Further, as the crosslinking agent that can be incorporated into the composite composition of the present invention, water-soluble melamine, epoxy resin, ammonium zirconium carbonate salt or zirconium complex compound,
Alternatively, there are mixtures of two or more of these, and by adding such a crosslinking agent, the hydrophilic polymer compound is crosslinked and rendered insoluble.

In addition, in such a composite composition, by changing the ratio of the above-mentioned first component and second component, the properties of the resulting composite film will change greatly. The basic concept is that when the ratio of the first component that provides the film-forming composition is increased, the surface of the cured composite film is roughened and its hydrophilicity increases. In addition, due to the relationship between the amount of the composite film and press formability, as the film of the first component becomes thicker, in other words, the amount of alkali silicate in the composite film increases, especially in drawless press forming. Ironing cracks and damage to the flared portion become more likely to occur.

Therefore, in the present invention, in order to obtain good surface micromorphology and hydrophilicity, the amount of Si in the composite film (cured film) covering the surface of the fin material is 5 to 150 mg/m2.
It is desirable that it be regulated within the range of . Note that this Si
If the Si amount exceeds 150 mg/m", problems will arise in practical press formability, and if the Si amount exceeds 5 rag/m"
If the amount is less than that, the composite film layer including the polymer resin layer will also become thinner, resulting in the problem of loss of parent wood durability.

In addition, in order to form a composite film having such a Si content, the alkali silicate as the first component and the hydrophilic polymer compound as the second component are generally mixed in an amount of 10% by weight.
A composite composition is formed by blending the components at a ratio of /1 to 10/6. Note that this ratio is 10
When the ratio is greater than 1, the surface of the composite film becomes too rough, retaining press oil during press molding more than necessary, and degreasing performance after assembling the heat exchanger decreases.
When the ratio of the polymer resin becomes smaller than 0/6, the degree of roughening of the composite film is insufficient, the receding contact angle becomes large, and the water wettability decreases.

In addition, the composite film formed on the surface of the fin material by the composite composition according to the present invention is specifically 0.0
The film thickness is about 3 μm to 1.5 μm, and if the film is too thin, the sustainability of the mother tree will be poor, as can be understood from the above explanation, and if the film is thick, it will not work properly during press forming. There are problems such as the oil tends to remain in the composite film, the contact angle of water: θ820 varies, and the color tone tends to be uneven in the areas where the oil remains.

In addition, the above-mentioned crosslinking agent, leveling agent, stabilizer, antifoaming agent, etc. may be added to the composite composition composed of the first component and the second component as necessary. , is applied to a fin material made of a predetermined aluminum or aluminum alloy to form a coating film of a predetermined thickness, and further thereafter, this coating film is cured, thereby achieving the desired precoating treatment according to the present invention. A fin material will be formed.

In addition, when forming a film made of the above-mentioned composite composition on such fin material, the coating method for the fin material in strip form of such composite composition is basically a one-coat one-bake method. It is also possible to control the film thickness by using a two-coat one-bake method, and it is also possible to coat to a predetermined film thickness using a dip method or a spray method. It is. The coating film made of the composite composition formed on the surface of the fin material is preferably cured (crosslinked) by heating, and the heating temperature at that time is determined by the hydrophilic composition as the second component. It varies depending on the type of polymer compound, the type of crosslinking agent as a hardening agent, etc., and it is difficult to define it unambiguously. Then,
Generally, composite compositions are prepared and applied to fin materials so that they can be cured at a temperature of 160° C. or higher.

The precoated fin material according to the present invention obtained in this way is in the form of a flat plate in the form of a strip,
This is subjected to various molding processes to form predetermined fin parts, and then combined with tubes and the like to form the intended heat exchanger.

(Effects of the Invention) As is clear from the above description, the fin material according to the present invention has a pre-coated film having hydrophilicity and corrosion resistance, and is advantageously formed with such a pre-coated film. In addition, it has excellent press formability such as stretching, drawing, punching, ironing, and flaring, and has excellent characteristics that are not found in conventional pre-coated fin materials. It is something that you have.

(Examples) In order to clarify the present invention more specifically, some examples of the present invention will be shown below, but the present invention should not be construed as being limited by the description of such examples. It goes without saying that this is not the case.

It should be noted that the present invention can be implemented in various embodiments in addition to the above-described detailed description of the present invention and the following examples, and as long as they do not depart from the spirit of the present invention,
It should be understood that any of the various embodiments that can be implemented based on the knowledge of those skilled in the art belong to the scope of the present invention.

Example 1 0.12% Mn, 0.04% Ti, 0.06% Z
n and 0. 0.1 in thickness from A1 alloy containing 5% Ga and the balance consisting of Al and unavoidable impurities.
A 10 Tsuru H26 material (CAI coil material) was produced, and the coil material was subjected to the following treatments to obtain the intended fin material.

That is, the coil material was subjected to a 3% aqueous solution of an alkaline Alt degreaser (Nippon Paint Co., Ltd.: Ridrin #322N8) containing sodium phosphate and borate at 60°C for 5 seconds. Spray degreasing and etching were performed, followed by washing with water. Next, this degreasing and
The etched Aj2 coil material was soaked in a bath consisting of chromic acid, phosphoric acid, and hydrofluoric acid (manufactured by Nippon Paint: 3% 10.
A chemical conversion treatment was performed at 60° C. for 5 seconds using 5% alodine #401/45) to form a phosphoric acid chromate film on the surface of the coil material, followed by washing with water and drying. Note that the amount of Cr in the chemical conversion film at this time was 20 mg/
It was m2.

Next, the obtained chemical conversion treated coil material was treated with S.
Polyacrylic acid (solid content: 13%) and zirconium ammonium carbonate (solid content) as its curing agent were added to 10 parts of a potassium silicate solution (solid content: 30%) at a ratio of i Oz / K z O = 2.5. :13%) respectively. Coating was performed using coil coating so that the dry thickness was 0.08 μm, and forced drying was performed at 200° C. for 20 seconds.

The thus obtained coated plate was press-molded using Shell B (manufactured by Shell Oil Co., Ltd.) as processing oil at an ironing rate of 50%, and a heat exchanger unit with a fin pitch of 1.5 fi was assembled.

Then, this heat exchanger unit was degreased with hot and cold steam using TriClean, and the ventilation resistance was measured, and the front wind speed was 1 m / . 0, the dry/wet pressure loss ratio was 1.2 for the treated material, compared to 3.0 for the untreated material.
It had dropped to 5.

In addition, when the heat exchanger unit was operated as an evaporator for 8 hours during the day and left to dry for 16 hours at night, 10 cycles were repeated, and the ventilation resistance was then measured. It was observed that there was almost no change, and the dry/wet pressure loss ratio also remained almost unchanged.

The above-mentioned press forming was performed continuously for 1 million shots using the above-mentioned coil, but no phenomenon such as seizure was observed on the die tool, and no flare cracking occurred, indicating that good forming was achieved. showed his sexuality.

Comparative Example Aj without adding Zn and Ga! -Mn-Ti alloy (
After degreasing and etching in the same manner as in Example 1 and further performing chemical conversion treatment, the chemical conversion film (phosphoric acid chromate film) was A hydrophilic cured film similar to that in Example 1 was applied and baked on top. Furthermore, Example 1
The heat exchanger Uni-
After assembling the throat, I applied the same trichlene degreasing.

During such trichlene degreasing, unevenness in the glossy surface was observed, as if some processing oil remained on the fin surface. Furthermore, when the ventilation resistance was measured using this assembled unit under the same conditions as in Example 1, the dry/wet pressure loss ratio was 1.
It was 75. At this time, when observing the state of adhesion of condensate and its tendency to flow down, it was observed that some of the condensed water was in the form of droplets in areas that appeared less glossy.

When such coated plates were examined in detail, it was found that in some cases the base surface could be seen as is due to poor degreasing within the field of view of the microscope. Furthermore, when the uniformity of the chemical conversion film was investigated for Cr using a scanning electron microscope, it was found that the amount of Cr was reduced in the areas where the degreasing and etching were defective. Furthermore, when the uniformity of the coating was investigated by looking at the distribution of Si in the coating film, it was found that in areas where the amount of Cr was low due to poor etching, the amount of St was also low, and there was also variation in the coating film.

Further, when such a coated coil was subjected to a continuous punching test, seizure occurred on the tool at the stage of 60,000 shots, and flare cracking occurred at that location. Thereafter, as the number of shots increased, this tendency became more pronounced, and in the end, the formability of this coil was not sufficient.

Example 2 From the results of Example 1 and Comparative Example above, the chemical composition (alloy composition) of the Al material and the uniformity of degreasing and etching are related to the hydrophilic treatment (formation of a hydrophilic film) and press formability. From this understanding, H2B-treated AJ coil materials made of Afi alloys with various alloy compositions as shown in Table 1 below were degreased using the same alkaline degreasing solution as in Example 1.・Etching treatment, /
We investigated the relationship between the chemical composition of one material and its degreasing and etching properties.

The results are also shown in Table 1 below. In addition, alloy N
111.4.7-9 are according to the invention and alloys 11 & 12.3.5.6 are comparative alloys.

As is clear from Table 1, when the amount of Zn and Ga added is small (alloys 2 and 5), the etching property is poor, and when the amount added is large (alloys 11h3 and 6), the amount of dissolution on the coil surface is poor. is recognized to be large. However, the first
In the case of Alloy Fish 3.6 in the table, there was a tendency for the etched surface to become rough, perhaps because the Zn eluted in the alkaline bath re-precipitated, and the finished appearance was not completely satisfactory.

Claims (6)

[Claims] (1) An aluminum fin material for a heat exchanger, in which a hardened film of a composite composition consisting of an alkali silicate and a hydrophilic polymer compound is further formed on a chemical conversion film formed on the surface of an aluminum plate material. , such aluminum plate material contains 0.04 to 0.10% Zn, 0.1 to 0.1% by weight.
0.5% Mn, 0.002-0.03% Ga and 0
．． An aluminum fin material for a heat exchanger, characterized in that it is made of an aluminum alloy containing 0.02 to 0.15% Ti. (2) The aluminum fin material according to claim 1, wherein the chemical conversion coating is a chromate coating containing 3 to 30 mg/m^2 of Cr. (3) Claim 1 or 2, wherein the cured film is formed with a thickness of 0.03 to 1.5 μm.
Aluminum fin material described in section. (4) An aluminum fin material for a heat exchanger, in which a hardened film of a composite composition consisting of an alkali silicate and a hydrophilic polymer compound is further formed on the chemical conversion film formed on the surface of the aluminum plate material. , such aluminum plate material contains 0.04 to 0.10% Zn, 0.1 to 0.1% by weight.
0.5% Mn, 0.002-0.03% Ga and 0
．． 0.02 to 0.15% Ti, and further contains 0.0
0005-0.0005% B and 0.0001-0.
An aluminum fin material for a heat exchanger, characterized in that it is made of an aluminum alloy containing 0.002% Be. (5) The aluminum fin material according to claim 4, wherein the chemical conversion film is a chromate film containing 3 to 30 mg/m^2 of Cr. (6) Claim 4 or 5, wherein the cured film is formed with a thickness of 0.03 to 1.5 μm.
Aluminum fin material described in section.