JP3157149B2 - Method of manufacturing high strength sacrificial anode fin material made of aluminum alloy for heat exchanger manufactured by brazing - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method of manufacturing a high-strength sacrificial anode Al alloy fin material for a heat exchanger, which is to be brazed.

[Prior art] Conventionally, heat exchangers widely used in automobile cooling and the like are manufactured by joining a fin material made of an aluminum alloy, which is lightweight and has excellent thermal conductivity, by vacuum brazing or the like. I have.

The fin material may be required to have sacrificial anode performance in order to prevent corrosion of a tube material of a heat exchanger and the like. After casting at about 30 ° C./second), fin materials are obtained by performing processing such as rolling.

[Problems to be Solved by the Invention] By the way, in recent years, from the viewpoint of further reducing the weight of the heat exchanger and reducing the production cost, the demand for thinner fin materials has been increasing. There is a demand for higher strength.

Conventionally, according to this request, Mn, S
Elements such as i, Fe, and Zr are added to improve the strength of the fin material.

However, the above-mentioned elements increase the strength of the Al alloy as the addition amount to the Al alloy base increases, but lowers the thermal conductivity, further increases the potential of the material, and increases the sacrificial anode effect of the fin material. Lower. Therefore, there is a problem in that the amount of addition of these elements is limited, and it is not possible to achieve a sufficiently high strength, which is a barrier to thinning.

The present invention has a basic object of solving the above problems, and can achieve high strength without impairing the sacrificial anode effect. A method for producing a strength sacrificial anode fin material is provided.

[Means for Solving the Problems] The inventors of the present application have studied to solve the above problems, and as a result, while limiting the type and amount of the added element,
Al-Fe system, Al-Fe-Si system, Al-Fe-Mn system, Al-Fe system
It has been found that precipitates such as -Si-Mn system and AL-Zr-Si system are remarkably finely dispersed to improve the strength, and that the thermal conductivity and the sacrificial anode effect are not impaired.

That is, the first invention of the invention of the present application is Si 0.2-0.
An Al alloy containing 8 wt% and 0.8 to 1.5 wt% Fe and the balance being Al and unavoidable impurities is cast at a solidification rate of 100 ° C./sec or more.

The second invention is characterized in that Si 0.2 to 0.8 wt% and Fe 0.8
1.51.5 wt%, Zr 0.05-0.2 wt%, Mn 0.
An aluminum alloy containing 1 to 0.8 wt% of one or two kinds, the balance being Al and unavoidable impurities, is cast at a solidification rate of 100 ° C./sec or more.

In addition, the fin material obtained by the present invention is then provided for brazing, but the brazing method is not particularly limited. However, the present invention is suitable for a case where a vacuum brazing method is employed.

The reasons for limiting the solidification rate and the content of the additive element in the structure of the present invention will be described below.

(1) Solidification speed during casting By increasing the solidification speed during casting, Al-Fe
System, Al-Fe-Si system, Al-Fe-Mn system, Al-Si-Mn system, Al-
Precipitates such as Zr—Si are finely dispersed, and the strength is remarkably improved.

When the solidification rate is less than 100 ° C./sec, the above-mentioned precipitates are not sufficiently refined, and the contribution to the improvement in strength is small. Therefore, the solidification rate during casting is 10
0 ° C / sec or more.

In addition, the solidification method is not particularly limited, and in short, any method may be used as long as it is cast by a method that satisfies the above solidification speed. Specific examples include a continuous casting method, a semi-continuous casting method, and a casting using a water-cooled mold.

(2) Si, Fe Si and Fe are dispersed as Al-Fe-based and Al-Fe-Si-based compounds in the AL substrate to improve the room temperature strength of the fin material and the buckling resistance during brazing.

The above effect cannot be obtained when Si is less than 0.2 wt%. If Fe is less than 0.8% by weight, Si that cannot be combined with Fe precipitates during casting and further forms a solid solution during brazing, making the potential noble and reducing the sacrificial anode effect.

Therefore, Si should be 0.2 wt% or more, and Fe should be 0.8 wt% or more.

Also, when Si is added in excess of 0.8 wt% and Fe is added in excess of 1.5 wt%, the amount of each solid solution in the aluminum base increases, the potential becomes noble, the sacrificial anode effect is reduced, and the thermal conductivity is reduced. Lower.

For this reason, the content of Si is limited to the range of 0.2 to 0.8 wt%, and the content of Fe is limited to the range of 0.8 to 1.5 wt%.

(3) Mn and Zr Mn and Zr to be added as required may be Al-Mn-Si, Al-Mn-Fe, Al-Zr-Si in Al-Fe-Si alloys.
It is dispersed as a compound such as a system and improves the strength. This effect cannot be obtained with Mn less than 0.1% and Zr less than 0.05%. On the other hand, when Mn is added in excess of 0.8 wt%, the amount of solid solution in the Al base increases, the potential becomes noble, the sacrificial anode effect is reduced, and the thermal conductivity is reduced.

Further, even if Zr is added in excess of 0.2% by weight, no further improvement in the effect can be expected, and further, the workability is reduced.

Therefore, the addition amount of Mn is in the range of 0.1 to 0.8 wt%, and the addition amount of Zr is in the range of 0.05 to 0.2 wt%.

[Operation] In other words, according to the present invention, by casting at a high solidification rate, the Al alloy is quenched, and Fe and Si, and optionally, Mn and Zr, are added as an Al compound in the Al base. It finely precipitates and disperses to improve the strength of the fin material.

In addition, in brazing, the fin material is heated and cooled, so that the compound that has segregated during casting also becomes a state of being uniformly and finely dispersed in the base material by re-solid solution and precipitation, thereby ensuring strength improvement. .

Further, at the time of brazing, the compound of solid solution is promoted without being combined with other elements at the time of casting, and this compound is precipitated at the time of cooling of brazing.
It can be increased more than previously thought.

Therefore, even if the above elements are sufficiently added, a desired sacrificial anode effect can be obtained, and a fin material having high strength and excellent sacrificial anode effect can be obtained.

Example An example of the present invention will be described below.

An aluminum alloy having the composition shown in Table 1 was melted and cast,
A fin material having a thickness of 100 μm was obtained by rolling.

The fin material (specimens: Nos. 1 to 14) was made of dissolved Al
This is an example according to the method of the present invention obtained by solidifying an alloy by a semi-continuous casting method or a continuous casting method in which the solidification rate is increased, for example, by increasing the water cooling effect.

On the other hand, the fin materials (test pieces: Nos. A to g) are comparative examples not based on the production method of the present invention, and specifically,
The Al alloy is solidified by a conventional semi-continuous casting method having a low solidification rate, or the component composition is out of the range of the present invention.

Incidentally, each of the obtained test pieces of the example and the comparative example, at 600 ° C. in a vacuum of 10 ⁻⁵ Torr, assuming vacuum brazing,
After holding for 5 minutes, it was cooled at a cooling rate of 120 ° C./sec (assuming cooling after brazing).

Each specimen was 5% Na to evaluate the sacrificial anode effect.
Pitting corrosion potential (standard calomel potential: SCE) was measured in Cl solution. Further, a tensile test was performed for the purpose of evaluating the strength evaluation.

As shown in Table 1, the results of the above evaluation showed that the test pieces of the examples had excellent sacrificial anode effects and strengths.

On the other hand, in the test piece of the comparative example, the strength was insufficient or the sacrificial anode effect was inferior.

In addition, in the test piece g of the comparative example, in addition to the above evaluation, the result that the workability was reduced was obtained.

[Effects of the Invention] As described above, according to the first invention of the method for producing an Al alloy high-strength sacrificial anode fin material of a heat exchanger manufactured by brazing according to the present invention, Si 0.2 to Impairing the sacrificial anode effect and thermal conductivity because an Al alloy containing 0.8 wt% and Fe 0.8-1.5 wt%, the balance being Al and unavoidable impurities, is cast at a solidification rate of 100 ° C / sec or more. Therefore, there is an effect that the thickness can be reduced without deteriorating the performance.

Further, according to the second invention, Si 0.2 to 0.8 wt% and F
e 0.8-1.5wt%, Zr 0.05-0.2wt%,
Mn 0.1 ~ 0.8wt% contains one or two kinds, the balance is Al
In addition, since an Al alloy including unavoidable impurities is cast at a solidification rate of 100 ° C./second or more, there is an effect that, in addition to the above effects, a further improvement in strength is achieved.

Continuation of the front page (51) Int.Cl. ⁷ identification code FI // C22C 21/00 C23F 13/00 E (58) Field surveyed (Int. Cl. ⁷ , DB name) C22C 1/02 B22D 27/04 B23K 1/00 330 B23K 1/19 C23F 13/14 C22C 21/00-21/18

Claims (2)

(57) [Claims] An aluminum alloy containing 0.2 to 0.8 wt% of Si and 0.8 to 1.5 wt% of Fe and the balance of Al and unavoidable impurities is cast at a solidification rate of 100 ° C./sec or more. Of high-strength sacrificial anode fin material made of Al alloy for heat exchanger produced by brazing 2. The composition contains 0.2 to 0.8 wt% of Si and 0.8 to 1.5 wt% of Fe, and further contains 0.05 to 0.2 wt% of Zr and 0.1 to 0.8 wt% of Mn.
Characterized in that an Al alloy containing one or two of the following, and the balance consisting of Al and unavoidable impurities, is cast at a solidification rate of 100 ° C./sec or more, and the Al alloy of the heat exchanger manufactured by brazing. Method of manufacturing high strength sacrificial anode fin material made of alloy