JPH032343A - Aluminum alloy for heat-exchanger fin - Google Patents

Abstract

PURPOSE:To obtain an Al alloy for heat-exchanger fin capable of thinning, excellent in formability even if sheet thickness is reduced, and capable of working by a draw and drawless forming method by adding specific amounts of Fe, Cu, and Ti to Al and controlling Si content to a low value. CONSTITUTION:A slab of an Al alloy having a composition which contains, by weight, 0.8-2.0% Fe, 0.05-0.5% Cu, and 0.01-0.15% Ti and in which Si content is limited to <=0.10% is subjected to homogenizing heat treatment and then worked into a sheet metal as heat-exchanger fin material by means of hot rolling and cold rolling. By this method, the Al alloy easy of forming by a draw method and a drawless method and suitable for heat-exchanger fin material can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an aluminum alloy for heat exchanger fins,
In particular, it has excellent formability, and even if the plate thickness is made thinner, there is less collar cracking during fin press forming, and the plate thickness can be reduced, and it can be applied to both the draw method and drawless method as forming methods. This relates to aluminum alloys that can be produced.

(Prior Art and Problems to Be Solved) Generally, aluminum fin materials are made by forming an aluminum plate into a desired shape by press working, and are used in combination with a steel pipe.

In recent years, attempts have been made to reduce the thickness of aluminum plates as much as possible in order to improve the efficiency and make heat exchangers more compact.
．． It is being used up to a thickness of 1 mm.

However, as the wall thickness becomes thinner, there is a significant decline in formability, especially stretchability and stretch flangeability, and molding defects called collar cracking and collar skipping occur during fin processing.
It was an obstacle to becoming flesh.

In addition, the conventional forming method was a draw-less method that mainly involved stretch processing using industrial pure aluminum such as 1050.1100, but a draw-less method that incorporates ironing has been developed. Alloys more suitable for the process (e.g. Al-Fe-Mn alloy, An-Mn-
Zr alloy, etc.) have also been developed, and thinning has been promoted (
(See Special Publication No. 56-37294 and Special Publication No. 10987-1987).

However, in the drawless method, it is necessary to control tempering (H24, H26, etc.) in order to improve formability, but there is a drawback that formability tends to fluctuate and quality is not stable.

In addition, with conventional alloys, it is necessary to use separate alloys for drawless and draw applications, which complicates the process, so there has been a desire to develop an aluminum alloy that can be used for both purposes with the same alloy.

The present invention has been made in response to such demands, and it is possible to reduce the thickness of the plate, and has excellent formability even when the plate thickness is reduced.
Moreover, it is an object of the present invention to provide an aluminum alloy for heat exchanger fins that can be applied to both draw and drawless forming methods.

(Means for Solving the Problems) In order to achieve the above object, the present inventor has conducted intensive research on aluminum alloy compositions that can be applied to any of the draw drawless forming methods, and has hereby developed an aluminum alloy composition with a new composition. The present invention was created by discovering the alloy.

That is, the aluminum alloy for heat exchanger fins according to the present invention contains Fe: 0.8 to 2.0% and Cu: 0.

It is characterized by containing 0.05 to 0.50% and Ti: 0.01 to 0.15%, Si: regulated to 0.10% or less, and the remainder consisting of Al and inevitable impurities.

The present invention will be explained in more detail below.

(effect) The reasons for limiting the chemical components in the present invention will be shown.

Fe: 0.8 to 2.0 Fe produces many crystallized substances, has the effect of refining subgrains and crystal grains, and improves moldability, that is, stretchability, elongation, stretch flangeability, etc. It has the effect of improving

The presence of crystallized substances also improves ironing processability, and not only with the draw process method.

The present invention is applicable to any of the drawless forming methods. In addition, F dissolved in Afl
Since e suppresses the movement of dislocations due to heating, it also has the effect of stagnating heating softening and widening the applicable temperature range when manufacturing tempered materials such as H26, H24, and H22, making it easier to manufacture. .

However, if the Fe content is less than 0.8%, the above effect is insufficient, and if it exceeds 2.0%, crystallized substances become excessive, producing large products with a size of 10 μm or more, which are molded. It becomes a stress concentration point during processing and causes cracks.

Therefore, the amount of Fe should be in the range of 0.8 to 2.0%, and 1
．． A range of 0 to 1.7% is preferred.

Cu: 0.05-0.50% Cu dissolved in Al, like the above-mentioned Fe, stagnates heating softening, and is suitable for the temperature box II when manufacturing tempered materials such as H26, H24, and H22. 1 width, contributing to stable quality. In addition, solid-dissolved Cu is effective in improving strength, and enables thinning due to high strength.

However, if Cu is less than 0.05%, the above effect is insufficient, and if it exceeds 0.50%, the strength will be excessively high and the moldability will be poor.

Therefore, the amount of Cu is in the range of 0.05 to 0.50%.

Ti: 0.01 to 0.15% Ti has the effect of making the solidified structure finer, thereby making the structure finer in the product, and improving formability. Also, T
By trapping dislocations formed during processing, i restrains the movement of dislocations and generates a fine substructure,
By stagnating the softening (disappearance of dislocations) during heating,
It has the same effect as u.

However, if it is less than 0.01%, the effect is insufficient;
Moreover, when it exceeds 0.15%, the effect is saturated, and on the contrary, a huge intermetallic compound of Ti and Al is generated, which deteriorates the formability.

Therefore, the amount of Ti is in the range of 0.01 to 0.15%.

SIo, 10% or less Si affects the form of Fe crystallized products, and has the function of increasing the size of the crystallized products, decreasing their number, and reducing the amount of solid solution Fe. Therefore, in order to fully demonstrate the function of Fe, it is necessary to regulate it, so SiS2.
10%.

Other than the above elements, alloying elements are not actively added.
It may contain impurities. Impurities are allowed to the extent that they do not impair the effects of the present invention. In particular, conventional alloys (Mn, Zr
If elements such as are added, they are easily affected by manufacturing conditions, especially temperature conditions such as agglomeration, homogenization heat treatment, hot rolling, etc., and the quality is unstable, so it is better not to add them, and each element should be added as much as possible. It is preferable to regulate it to a minimum of 0.05%.
Less than is desirable.

Next, examples of the present invention will be shown.

(Example) After producing a slab by ingotting an aluminum alloy having the chemical components shown in Table 1 by a normal method, homogenization heat treatment was performed at 480°C, and hot rolling was carried out to form a hot rolled plate (3, 5
mm thickness) was manufactured. Continued cold rolling to 110
Rolling was carried out to μ-thickness.

Thereafter, tempered materials of Q22 and Q26 were produced by final annealing. H゛26 material is made into Q22 by draw processing method.
Each material has a fin diameter of 9.5 mm using the drawless processing method.
Fin press processing was performed under the conditions of 85 mφ and fin pitch of 1.7111 m, and the formability (collar cracking, Erichsen value, elongation, limit elongation flangeability) and strength were investigated. The results are also listed in Table 1.

As is clear from Table 1, the examples of the present invention are applicable to the draw machining method (Ilk & 3) or the drawless machining method (NQ9).
) In both processing methods, there is almost no occurrence of collar cracking etc. in thinning, excellent moldability and predetermined strength are obtained.

On the other hand, all of the comparative examples having chemical components outside the range of the present invention have poor workability, and in the case of the special drawless processing method, color cracking occurs, etc. Therefore, it can be used for both the drawless and draw processing methods. Not suitable for.

[Margin 1 (Effects of the Invention) As detailed above, according to the present invention, the following excellent effects can be obtained.

■ Excellent formability is achieved even with a thin thickness, making it possible to reduce the thickness and increase the number of fin stages.
Improves heat exchanger performance.

■ The amount of aluminum used can be reduced for the same performance, resulting in cost reduction.

■ For both draw and drawless forming methods, tI
The same aluminum alloy can be used by simply changing the four qualities, improving productivity.

■ Semi-rigid materials such as H26, H24, and H22 can be manufactured stably, making it possible to reduce manufacturing costs and stabilize quality.

Patent applicant: Kobe Steel, Ltd. Representative Patent Attorney Takashi Nakamura

Claims (1)

[Claims] In weight% (hereinafter the same), Fe: 0.8 to 2.0%, C
u: 0.05-0.50% and Ti: 0.01-0.1
5%, Si: regulated to 0.10% or less, and the remainder is A.
1. An aluminum alloy for heat exchanger fins, characterized by comprising l and inevitable impurities.