JP5447593B2 - Aluminum alloy fin material for heat exchanger - Google Patents

Description

  The present invention relates to an aluminum alloy fin material for a heat exchanger.

  The aluminum heat exchanger is configured by brazing an aluminum alloy fin material to an aluminum working fluid passage constituting material or the like. In order to improve the performance characteristics of the heat exchanger, the basic characteristics of this aluminum alloy fin material are that the sacrificial anode effect is required to prevent the working fluid passage constituent material from being corroded, and it is deformed by high-temperature heating during brazing. Therefore, excellent sag resistance and erosion resistance are required so that the wax does not penetrate.

  In order to satisfy the above basic characteristics, Mn and Fe are added to the fin material, but recently, the manufacturing process has been devised to further reduce the tensile strength before brazing and after brazing. Aluminum alloy fins for heat exchangers with high tensile strength have been developed.

  In Patent Document 1, Si: 0.8 to 1.4 wt%, Fe: 0.15 to 0.7 wt%, Mn: 1.5 to 3.0 wt%, Zn: 0.5 to 2.5 wt% In addition, Mg as an impurity is limited to 0.05 wt% or less, a molten metal composed of ordinary impurities and Al is poured into the remaining, and a thin slab having a thickness of 5 to 10 mm is continuously formed by a twin belt type casting machine. After casting and winding on a roll, it is cold-rolled to a thickness of 0.05 to 0.4 mm, subjected to intermediate annealing at 350 to 500 ° C., and cold-rolled with a cold rolling rate of 10 to 50%. A method for producing aluminum alloy fins for heat exchangers having a plate thickness of 40 to 200 μm and a tensile strength before brazing of 240 MPa or less and a tensile strength after brazing of 150 MPa or more is disclosed.

  On the other hand, a heat exchanger manufacturing method for obtaining a predetermined strength by specifying a cooling rate after brazing when an aluminum alloy fin material is brazed to a working fluid passage constituent material made of aluminum has also been developed.

  Patent Document 2 discloses a method for manufacturing a heat exchanger that obtains fins having high tensile strength after brazing heating, focusing on the cooling rate after brazing heating. Specifically, when producing an Al heat exchanger by brazing, cooling from a brazing temperature to 350 ° C. is performed at a cooling rate of 100 ° C./min to 1000 ° C./min, so that a fin having a high tensile strength is obtained. It is the manufacturing method of the heat exchanger to obtain.

  In Patent Document 3, tubes and fins are laminated, headers are attached to both ends of the tube, chloride flux is used, air, dry air or fluoride non-corrosive flux is used, and inert gas is used. In the manufacture of aluminum heat exchangers to be brazed and joined, brazing sheets are used, tubes with an outer surface made of an Al-Si alloy brazing material and an inner surface made of an Al-Zn alloy, and after brazing A method for producing an aluminum heat exchanger is disclosed in which the cooling from 500 ° C. to 200 ° C. is performed at a rate of 50 ° C./min or more.

  However, in the above-mentioned Patent Document 1, there is a description about the conductivity (heat conductivity) after brazing heating, but there is no description about the cooling rate after brazing heating.

  In addition, the above Patent Documents 2 and 3 disclose a technique for obtaining a high-strength fin material by specifying a cooling rate after brazing heating. However, the conductivity (thermal conductivity) after brazing heating is disclosed. ) Is not found.

  Furthermore, recently, in order to further reduce the thickness of the fin material, in addition to basic brazing characteristics, development of an aluminum alloy fin material that has high proof strength after brazing and excellent thermal conductivity after brazing. It was desired.

JP 2005-220375 A Japanese Unexamined Patent Publication No. 1-91962 JP-A-2-142672

  The object of the present invention is to provide a sag resistance that has a moderate strength before brazing that is easy to form a fin, has a high strength after brazing, and has a high thermal conductivity (conductivity) after brazing. Another object of the present invention is to provide an aluminum alloy fin material for a heat exchanger that is excellent in erosion resistance, self-corrosion resistance, and sacrificial anode effect.

  In order to achieve the above object, according to the present invention, Si: 0.7 to 1.4 wt%, Fe: 0.5 to 1.4 wt%, Mn: 0.7 to 1.4 wt%, Zn: Including 0.5 to 2.5 wt%, Mg as an impurity is limited to 0.05 wt% or less, the balance is inevitable impurities and Al, the tensile strength after brazing is 130 MPa or more, the proof stress is High strength and heat transfer characteristics, erosion resistance, sag resistance, characterized by being 45 MPa or more, recrystallized grain size after brazing of 500 μm or more, and conductivity of 47% IACS after brazing Provided is an aluminum alloy fin material for a heat exchanger that is excellent in heat resistance, sacrificial anode effect and self-corrosion resistance. ≪ ＊ ≫

  In the method for producing the fin material of the present invention, a molten metal having the composition of the fin material is poured, and a thin slab having a thickness of 5 to 10 mm is continuously cast into a roll by a twin belt type casting machine. After winding, the first stage of cold rolling is performed to a plate thickness of 1.0 to 6.0 mm, the first intermediate annealing is performed at 250 to 550 ° C., and the second stage of cold rolling is performed. The thickness is set to 0.05 to 0.4 mm, the second intermediate annealing at 360 to 550 ° C. is performed, and the final cold rolling at a cold rolling rate of 20 to 75% is performed to obtain a final thickness of 40 to 200 μm. It is characterized by.

  Furthermore, in order to obtain a fin material having a high yield strength after brazing and excellent thermal conductivity after brazing, the inventor brazed the fin material into a heat exchanger together with the manufacturing process of the fin material itself. It came to the conclusion that it is important to control the cooling rate after attaching to an appropriate range.

  That is, the method for producing the aluminum heat exchanger of the present invention described above is the method for producing an aluminum heat exchanger by brazing and heating the fin material of the present invention, at least the brazing temperature after the brazing heating. To 400 ° C. is cooled at a cooling rate of 10 to 50 ° C./min.

  The aluminum alloy fin material for heat exchangers of the present invention has a high strength and excellent heat transfer characteristics, erosion resistance, resistance to resistance by specifying the composition, proof strength after brazing, recrystallized grain size, and conductivity. Sag, sacrificial anode effect and self-corrosion resistance can be secured.

  The manufacturing method of the fin material of the present invention uses a molten metal having the composition of the fin material of the present invention to form a thin slab with a twin-belt casting machine and cold rolling / annealing / cold rolling / annealing / cold under specified conditions. By performing hot rolling, a fin material having the above-mentioned various characteristics can be manufactured.

  The heat exchanger manufacturing method of the present invention precipitates Al—Mn precipitates and Al— (Fe · Mn) —Si based precipitates by defining the cooling rate after brazing the fin material of the present invention. And high conductivity can be achieved after brazing.

  The reason which limited the composition of the aluminum alloy fin material for heat exchangers of the present invention will be described.

[Si: 0.7 to 1.4 wt%]
Si coexists with Fe and Mn to form submicron-level Al- (Fe · Mn) -Si compounds during brazing, improving strength, and simultaneously reducing the amount of Mn solid solution to conduct heat. Improve degree (conductivity). If the Si content is less than 0.7 wt%, the effect is not sufficient, and if it exceeds 1.4 wt%, the fin material may melt during brazing. Therefore, the Si content is limited to 0.7 to 1.4 wt%. Preferably, the Si content is 0.8 to 1.2 wt%.

[Fe: 0.5 to 1.4 wt%]
Fe coexists with Mn and Si to produce submicron-level Al- (Fe · Mn) -Si compounds during brazing, improving strength and reducing Mn solid solution to conduct heat. Improve degree (conductivity). If the Fe content is less than 0.5 wt%, the strength decreases, which is not preferable. If it exceeds 1.4 wt%, coarse Al- (Fe.Mn) -Si-based crystallized products are produced during casting of the alloy, making it difficult to produce a plate material. Therefore, the Fe content is limited to 0.5 to 1.4 wt%. Preferably, the Fe content is 0.5 to 1.2 wt%.

[Mn: 0.7 to 1.4 wt%]
By coexisting with Fe and Si, Mn precipitates at a high density as a sub-micron level Al— (Fe · Mn) —Si compound at the time of brazing, and improves the strength of the alloy material after brazing. Further, since the submicron level Al- (Fe.Mn) -Si-based precipitate has a strong recrystallization inhibiting action, the recrystallized grains become coarser to 500 μm or more, and the sag resistance and erosion resistance are improved. If Mn is less than 0.7 wt%, the effect is not sufficient, and if it exceeds 1.4 wt%, coarse Al- (Fe · Mn) -Si-based crystallized products are produced during casting of the alloy, making it difficult to produce a plate material. At the same time, the solid solution amount of Mn increases and the thermal conductivity (conductivity) decreases. Therefore, the Mn content is limited to 0.7 to 1.4 wt%. Preferably, the Mn content is 0.8 to 1.3 wt%.

[Zn: 0.5 to 2.5 wt%]
Zn lowers the potential of the fin material and provides a sacrificial anode effect. If the content is less than 0.5 wt%, the effect is not sufficient. If the content exceeds 2.5 wt%, the self-corrosion resistance of the material is deteriorated, and thermal conductivity (conductivity) is lowered due to solid solution of Zn. Therefore, the Zn content is limited to 0.5 to 2.5 wt%. Preferably, the Zn content is 1.0 to 2.0 wt%.

[Mg: 0.05 wt% or less]
Mg is an impurity that affects the brazing property and may impair the brazing property when the content exceeds 0.05 wt%. Particularly in the case of fluoride-based flux brazing, fluorine (F), which is a component of the flux, easily reacts with Mg in the alloy, and works effectively during brazing due to the formation of compounds such as MgF _2. The absolute amount of flux to be used is insufficient, and brazing defects are likely to occur. Therefore, the Mg content is limited to 0.05 wt% or less.

  For impurity components other than Mg, Cu is preferably limited to 0.2 wt% or less in order to make the potential of the material noble, and Cr, Zr, Ti, and V significantly reduce the thermal conductivity of the material even in a small amount. Therefore, the total content of these elements is preferably limited to 0.20 wt% or less.

  Next, the reason for limitation of the conditions in the manufacturing method of the aluminum alloy fin material for heat exchangers of the present invention will be described.

[Continuous casting of thin slabs with a thickness of 5 to 10mm by a twin belt type casting machine]
In the double belt casting method, molten metal is poured between rotating belts facing each other up and down, and the molten metal is solidified by cooling from the belt surface to form a slab. It is a continuous casting method that is drawn out and wound into a coil.
In the manufacturing method of the present invention, the thickness of the cast slab is limited to 5 to 10 mm. With this thickness, the solidification rate in the central part of the plate thickness is fast, and with a uniform structure and with a composition within the range of the present invention, there are few coarse compounds and excellent properties with a large crystal grain size after brazing. It can be a fin material.

  When the thickness of the thin slab by the twin belt type casting machine is less than 5 mm, the amount of aluminum passing through the casting machine per unit time becomes too small and casting becomes difficult. On the contrary, if the thickness exceeds 10 mm, winding with a roll becomes impossible, so the slab thickness range is limited to 5 to 10 mm.

  In addition, it is preferable that the casting speed at the time of solidification of a molten metal is 5-15 m / min, and it is desirable that solidification is completed within a belt. A casting speed of less than 5 m / min is not preferable because it takes too much time for casting and decreases productivity. When the casting speed exceeds 15 m / min, the supply of the molten aluminum cannot catch up, and it becomes difficult to obtain a thin slab having a predetermined shape.

  Under the above casting conditions, the slab cooling rate (solidification rate) at a slab 1/4 thickness position during casting is about 20 to 150 ° C./sec. As the molten metal solidifies at a relatively high cooling rate, the size of an intermetallic compound such as Al— (Fe · Mn) —Si that crystallizes during casting within the range of the chemical composition of the present invention is 1 μm or less. Therefore, it is possible to increase the solid solution amount of elements such as Fe, Si and Mn in the matrix.

[The first stage cold rolling is performed to a plate thickness of 1.0 to 6.0 mm]
In order to obtain a sufficiently softened state in the subsequent first intermediate annealing and to sufficiently precipitate solid solution elements such as Si, Fe, and Mn in the matrix, the thickness of the first stage cold rolling is 1 Limited to 0.0 to 6.0 mm. If the plate thickness is thicker than 6.0 mm, the effect is not sufficient, and if it is less than 1.0 mm, the rollability deteriorates such as the occurrence of ear cracks during the first stage of cold rolling. Control is also required to balance the subsequent second-stage cold rolling and final cold rolling.

[The first intermediate annealing is performed at 250 to 550 ° C.]
The holding temperature of the first intermediate annealing is limited to 250 to 550 ° C. When the holding temperature of the first intermediate annealing is less than 250 ° C., a sufficient softened state cannot be obtained. When the holding temperature of the first intermediate annealing exceeds 550 ° C., solid solution elements such as Si, Fe, and Mn in the matrix are not sufficiently precipitated, and the thermal conductivity (conductivity) after the brazing heat is lowered. .

  The holding time of the first intermediate annealing is not particularly limited, but is preferably in the range of 1 to 5 hours. If the holding time of the first intermediate annealing is less than 1 hr, the temperature of the entire coil remains non-uniform and a uniform structure in the plate may not be obtained, which is not preferable. If the holding time of the first intermediate annealing exceeds 5 hours, it takes too much time for the treatment and the productivity is lowered, which is not preferable.

  The temperature increase rate and the cooling rate during the first intermediate annealing treatment are not particularly limited, but are preferably 30 ° C./hr or more. When the temperature raising rate and the cooling rate during the first intermediate annealing treatment are less than 30 ° C./hr, the treatment takes too much time and the productivity is lowered, which is not preferable.

  The temperature of the first intermediate annealing in the continuous annealing furnace is preferably 400 to 550 ° C. When the temperature is lower than 400 ° C., a sufficient softened state cannot be obtained. However, when the holding temperature exceeds 550 ° C., solid solution elements such as Si, Fe, and Mn in the matrix are not sufficiently precipitated, and the thermal conductivity (conductivity) after the brazing heat is lowered.

  The holding time for continuous annealing is preferably within 5 minutes. If the holding time for continuous annealing exceeds 5 minutes, it takes too much time for the treatment and productivity is lowered, which is not preferable.

  The heating rate and the cooling rate during the continuous annealing treatment are preferably 100 ° C./min or more for the heating rate. When the rate of temperature increase during the continuous annealing process is less than 100 ° C./min, the process takes too much time and productivity is lowered, which is not preferable.

[Furthermore, the second stage cold rolling is performed to a thickness of 0.05 to 0.4 mm.]
The second stage cold rolling is necessary for obtaining a sufficiently softened state in the subsequent secondary intermediate annealing and for sufficiently precipitating solid solution elements such as Si, Fe and Mn in the matrix.
If the plate thickness exceeds 0.4 mm, the effect is not sufficient. If the plate thickness is less than 0.05 mm, the reduction ratio applied to the subsequent final cold rolling cannot be controlled. For this reason, the plate thickness after the second cold rolling is limited to 0.05 to 0.4 mm.

[Secondary intermediate annealing at 360 to 550 ° C.]
The holding temperature of the second intermediate annealing is limited to 360 to 550 ° C. When the holding temperature of the second intermediate annealing is less than 360 ° C., a sufficient softened state cannot be obtained. However, if the holding temperature of the second intermediate annealing exceeds 550 ° C., solid solution elements such as Si, Fe, and Mn in the matrix are not sufficiently precipitated, and the thermal conductivity (conductivity) is lowered after the brazing addition heat. In addition, the recrystallization inhibitory action during brazing is weakened, the recrystallized grain size becomes less than 500 μm, and the sag resistance and erosion resistance during brazing are lowered.

  The holding time of the second intermediate annealing is not particularly limited, but is preferably in the range of 1 to 5 hours. If the holding time of the second intermediate annealing is less than 1 hr, the temperature of the entire coil remains non-uniform and a uniform structure in the plate may not be obtained, which is not preferable. If the holding time of the second intermediate annealing exceeds 5 hours, it takes too much time for the treatment and the productivity is lowered, which is not preferable.

  The temperature increase rate and the cooling rate during the second intermediate annealing treatment are not particularly limited, but are preferably 30 ° C./hr or more. When the temperature raising rate and the cooling rate during the second intermediate annealing treatment are less than 30 ° C./hr, the treatment takes too much time and the productivity is lowered, which is not preferable.

[Final cold rolling with a cold rolling rate of 20 to 75% is performed to obtain a final sheet thickness of 40 to 200 μm]
<Cold rolling ratio: 20 to 75%>
When the cold rolling rate in the final cold rolling is less than 20%, the strain energy accumulated by the cold rolling is small, and recrystallization is not completed during the temperature rising process during brazing, so sag resistance and erosion resistance Decreases. If the cold rolling rate exceeds 75%, the product strength becomes too high, and it becomes difficult to obtain a predetermined fin shape in the fin material forming. Therefore, the cold rolling rate in the final cold rolling is limited to 20 to 75%.
<Final plate thickness: 40 to 200 μm>
If the plate thickness of the fin material is less than 40 μm, the strength as a heat exchanger is insufficient, and the air heat conduction is lowered. When the plate thickness of the fin material exceeds 200 μm, the weight of the heat exchanger increases.

  The plate manufactured by the method for manufacturing an aluminum alloy fin material of the present invention is generally a clad plate made of 3003 alloy coated with a material for working fluid passage, such as brazing material, after slitting to a predetermined width and then corrugating. The heat exchanger unit is made by alternately laminating and flattening the flat tubes made of

The reason for limitation of the manufacturing conditions in the manufacturing method of the heat exchanger of this invention is demonstrated.
[Cooling at least in the temperature range from brazing temperature to 400 ° C after brazing heating at a cooling rate of 10-50 ° C / min]
The brazing of the aluminum heat exchanger is generally performed at about 600 ° C.
The temperature range from at least brazing temperature to 400 ° C. after brazing heating must be cooled at a cooling rate of 10 to 50 ° C./min. It is desirable to cool the temperature range from the brazing temperature after brazing heating to 300 ° C. at a cooling rate of 10 to 50 ° C./min. It is further desirable to cool the temperature range from the brazing temperature after brazing heating to 200 ° C. at a cooling rate of 10 to 50 ° C./min.

  In this way, the fin material of the present invention has a larger amount of Al-Mn precipitates and Al- (Fe · Mn) -Si-based precipitates as the cooling rate after brazing heating is slower. It is possible to achieve an electrical conductivity of 47% IACS or higher after attachment. When the cooling rate after brazing is less than 10 ° C./min, the productivity of the heat exchanger is significantly reduced. When the cooling rate after brazing exceeds 50 ° C./min, it becomes difficult to achieve a conductivity of 47% IACS or more after brazing. Moreover, if it is in the range of 10-50 degreeC / min with respect to the cooling rate after brazing of 50 degreeC / min or more, it can be set as the fin material with the high tensile strength and proof stress after brazing.

Examples of the present invention will be described below in comparison with comparative examples.
[Example 1] As an example of the present invention and a comparative example, a molten alloy having the composition of alloy numbers 1 to 9 shown in Table 1 was melted, passed through a ceramic filter, poured into a twin belt casting machine, and cast. A slab having a thickness of 7 mm was obtained at a speed of 8 m / min. The cooling rate during solidification of the molten metal at a slab thickness of 1/4 was 50 ° C./sec. The thin slab is cold-rolled to 4 mm, heated at a heating rate of 50 ° C./hr, held at 400 ° C. for 2 hr, and then cooled to 100 ° C. at a cooling rate of 50 ° C./hr. Was given. Next, after cold rolling to 120 μm, the temperature was raised at a heating rate of 50 ° C./hr, held at 400 ° C. for 2 hr, and then subjected to a second intermediate annealing treatment that was cooled to 100 ° C. at a cooling rate of 50 ° C./hr. . Subsequently, cold rolling was performed to obtain a fin material having a thickness of 60 μm.

As a comparative example, a molten alloy having the composition of Alloy No. 10 shown in Table 1 was melted and subjected to conventional DC casting (thickness: 560 mm, cooling rate at solidification: about 1 ° C./sec), chamfering, soaking, heat treatment A fin material having a thickness of 60 μm was manufactured by cold rolling, cold rolling (thickness 90 μm), intermediate annealing (400 ° C. × 2 hr), and cold rolling.
The following measurements (1) to (3) were performed on the fin materials of the present invention examples and comparative examples.

(1) Tensile properties before brazing Tensile strength (MPa) and elongation at break (%) of the fin material obtained above (2) Tensile properties, crystal grain size, conductivity after brazing [Brazing additional heat conditions] The temperature was raised at a rate of 20 ° C./min, held at 600 to 605 ° C. for 3 min, then cooled to 200 ° C. at a cooling rate of 20 ° C./min, then removed from the heating furnace and cooled to room temperature.
[Test items] [1] Tensile strength, yield strength (MPa) [2] Crystal grain size After electrolytic polishing of the surface to reveal a grain structure by the Barker method, grain size parallel to the rolling direction by a cutting method (μm) [3] Conductivity [% IACS] according to the conductivity test method described in JIS-H0505

(3) Brazing property (erosion test) Brazing material surface of brazing sheet (brazing material 4045 alloy cladding rate 8%) with a thickness of 0.25mm, which is a corrugated fin material coated with non-corrosive fluoride flux It was placed on top (load load 215 g), heated to 605 ° C. at a temperature rising rate of 50 ° C./min and held for 5 min. After cooling, the brazed cross section was observed, and a slight erosion of the fin material crystal grain boundary was judged as good (◯ mark), and a erosion was severe and the fin material melted markedly as poor (x mark). The corrugated shape was as follows.
Corrugated shape: height 2.3 mm × width 21 mm × pitch 3.4 mm, 10 peaks The measurement results are shown in Table 1.

  From the results in Table 1, it can be seen that the fin material produced by the method of the present invention has good tensile strength, brazing (erosion resistance) property, tensile strength after brazing, proof strength, and electrical conductivity.

  The fin material number 4 of the comparative example has a low Si content and low brazing strength, proof stress, and electrical conductivity.

  The fin material number 5 of the comparative example had a large Si content, and the erosion was inferior in the brazing evaluation.

  The fin material number 6 of the comparative example has a low Fe content, and has low tensile strength and electrical conductivity after brazing.

  The fin material No. 7 of the comparative example had a large Fe content, a large crystallized product was generated during casting, cracking occurred during cold rolling, and a fin material was not obtained.

  The fin material number 8 of the comparative example has a low Mn content and low tensile strength and proof stress after brazing.

  The fin material number 9 of the comparative example has a high Mn content, a high tensile strength of the H material, and a low conductivity after brazing.

  Fin material number 10 of the comparative example is DC casting (thickness: 560 mm, cooling rate at solidification: about 1 ° C./sec), chamfering, soaking, hot rolling, cold rolling (thickness: 90 μm), intermediate Fin material obtained by annealing (400 ° C. × 2 hr) and cold rolling, low proof stress after brazing, small crystal grain size after brazing, poor brazing (erosion resistance), brazing The conductivity after attaching is also low.

[Example 2] As an example of the present invention and a comparative example, the fin material of Alloy No. 2 obtained in Example 1 was cooled at various cooling rates when subjected to brazing addition heat treatment.
That is, the temperature was raised at a rate of temperature increase of 20 ° C./min, held at 600 to 605 ° C. for 3 minutes, and then cooled to the lower temperature shown in Table 2 (400 ° C., 200 ° C.) (60, 40 , 30, 20, 10 ° C./min), then removed from the heating furnace and cooled to room temperature.
For these fin materials subjected to brazing heat treatment, the tensile strength / proof strength and electrical conductivity after brazing were measured. The tensile test and the conductivity measurement were performed in the same manner as in Example 1. The measurement results are shown in Table 2.

  As shown in Table 2, numbers 2, 13, and 14 in which the fin material produced by the method of the present invention was brazed and heated under the cooling conditions after the brazing heat of the method of the present invention were 600 ° C to 200 ° C. It was found that good results were obtained in all of the tensile strength, proof stress, erosion resistance, and conductivity after brazing addition heat because the temperature range up to 20 ° C / min was cooled at a cooling rate of 20, 30 and 40 ° C / min.

  Nos. 11 and 12 in which the fin material manufactured by the method of the present invention was subjected to brazing addition heat under the cooling conditions after the brazing addition heat of the method of the present invention are the temperature range from 600 ° C to 400 ° C of 10 and 20 ° C / min. It can be seen that because of cooling at the cooling rate, good results were obtained in all of the tensile strength, proof strength, erosion resistance, and electrical conductivity after brazing heat.

  The fin material number 15 of the comparative example has a lower conductivity after brazing addition heat because the cooling condition after brazing addition heat was faster than the method of the present invention.

  Since the fin material number 16 of the comparative example is a DC cast slab rolled product and the cooling conditions after brazing addition heat were faster than the method of the present invention, the proof stress and conductivity after brazing addition heat are low.

  Since the fin material number 10 of the comparative example is a DC cast slab rolled product, the proof stress and conductivity after the brazing addition heat are low even though the cooling conditions after the brazing addition heating are within the scope of the method of the present invention. Low.

  According to the present invention, it has a moderate strength before brazing that can be easily formed by a fin, has a high strength after brazing, and has a high thermal conductivity (conductivity) after brazing, and has a high sag resistance. There are provided an aluminum alloy fin material for a heat exchanger excellent in erosion resistance, self-corrosion resistance and sacrificial anode effect, a method for producing the same, and a method for producing a heat exchanger using the fin material.

Claims (2)

Si: 0.7 to 1.4 wt%, Fe: 0.5 to 1.4 wt%, Mn: 0.7 to 1.4 wt%, Zn: 0.5 to 2.5 wt%, and further as impurities Mg is limited to 0.05 wt% or less, and has a composition consisting of the balance inevitable impurities and Al,
High strength, characterized in that the tensile strength after brazing is 130 MPa or more, the proof stress is 45 MPa or more, the recrystallized grain size after brazing is 500 μm or more, and the electrical conductivity after brazing is 47% IACS or more. An aluminum alloy fin material for a heat exchanger after brazing that is excellent in heat transfer characteristics, erosion resistance, sag resistance, sacrificial anode effect and self-corrosion resistance. Si: 0.7 to 1.4 wt%, Fe: 0.5 to 1.4 wt%, Mn: 0.7 to 1.4 wt%, Zn: 0.5 to 2.5 wt%, and further as impurities Mg is limited to 0.05 wt% or less, and has a composition consisting of the balance inevitable impurities and Al,
High strength and heat transfer characteristics, characterized in that the yield strength after brazing is 49 MPa or more, the recrystallized grain size after brazing is 500 μm or more, and the electrical conductivity after brazing is 47% IACS or more, Aluminum alloy fin material for heat exchanger after brazing with excellent erosion resistance, sag resistance, sacrificial anode effect and self-corrosion resistance.