JP4669709B2 - Brazing fin material and manufacturing method thereof - Google Patents

Description

  The present invention relates to a brazing fin material and a method for producing the same. And a manufacturing method thereof.

  A fin material used for a heat exchanger for an automobile such as a radiator by brazing is conventionally corrugated and brazed in combination with a tube material. In recent years, the demand for weight reduction and cost reduction of heat exchangers has been increasing, and the thinning of main members such as fin materials has further progressed. In order to maintain and improve the characteristics of the heat exchanger when thinning the fin material, recent fin materials have been improved in strength by adding various elements and studying the process. For example, as an example in which the additive element is changed, an Al—Fe—Ni alloy fin material excellent in strength and thermal conductivity (see Patent Documents 1 and 2) has been proposed. However, this alloy has remained a problem with respect to self-corrosion resistance for fin thinning. Further, as an example of examining the process, there is an Al—Fe—Mn—Si alloy fin material (see Patent Document 3) whose strength and conductivity are increased by specifying a cooling rate in continuous casting and rolling. 3, the fin material has an extremely small recrystallized grain size. Therefore, there is a high possibility that the fin material buckles by brazing diffusion during brazing, and it is not suitable for thinning. Patent Document 4 proposes a fin material having excellent strength after brazing, thermal conductivity, self-corrosion resistance, and erosion resistance. However, although the final cold rolling rate of the fin material described in the general literature is 15 to 50%, it is obvious that the material strength and the crystal structure shape are greatly different between the final cold rolling rates of 15% and 50%. Yes, this indicates that erosion resistance is not considered. Moreover, when the Example of general literature is seen, the intermediate annealing in all the Examples uses the continuous annealing for less than 1 minute. Back-calculating from the final plate thickness and the final cold rolling rate, continuous annealing is performed at a plate thickness of 0.11 mm, which is a condition that can be implemented only with limited facilities, which is quite difficult in industrial facilities. . A general continuous annealing furnace is assumed to be implemented with a plate thickness of 0.3 to 1.0 mm from the viewpoint of cost and performance. For example, when continuous annealing is performed at a plate thickness of 0.3 mm and then cold rolling is performed to 0.08 mm, the final cold rolling rate exceeds 70%, and erosion is extremely likely to occur.

  Furthermore, Patent Document 5 proposes a fin material having high strength and high thermal conductivity by using twin roll continuous casting rolling. This fin material enhances the diffusion resistance of the brazing by holding the rolling structure (fibrous structure) up to the brazing heat. However, strain remains in the material having a rolled structure up to the brazing heat, which may increase the strength of the material. If the strength of the fin material is high, the amount of springback is large, so the moldability of the fin material is reduced, and corrugation or press molding may not be possible.

As described above, thinning the fin material not only requires strength after brazing heat addition, thermal conductivity and corrosion resistance, but also excels in material strength before brazing heat addition and brazing diffusion resistance during brazing. For this purpose, the crystal structure of the material needs to be coarsely recrystallized.
Japanese Patent Laid-Open No. 7-216485 JP-A-8-104934 International Publication WO00 / 05426 Pamphlet JP 2002-256402 A JP 2002-241910 A

  The present invention is excellent in strength after brazing heat, heat conductivity and corrosion resistance, low in material strength before brazing heat, excellent in corrugation formation, and excellent in brazing resistance to brazing during brazing heat. And it aims at providing the method of manufacturing the fin material stably.

The present invention
(1) Fe: more than 1.0% and 2.2% or less (% indicating composition means “mass%”; the same applies hereinafter), Si: 0.5 to 1.5%, and Mn: 0.00. comprises 4 to 1.3% as essential components, as optional components, and 3.0% or less of Zn, and further one or more elements of the indicated element group by the following (a) and (b) In the range of 300 ° C. to 480 ° C., a final intermediate annealing is performed by casting an aluminum alloy containing the balance Al and inevitable impurities at a cooling rate of 10 ° C./second or more of the molten metal and performing a plate thickness of 0.1 mm or less. Formed into a rolled material having a crystal structure in which 80% or more of the surface area seen from the surface layer is occupied by recrystallized grains having a diameter of 10 mm or more in the rolling direction, formed by recrystallization of an aluminum alloy by the annealing. The final cold rolling is performed at a reduction rate of 30% or less. Method of manufacturing a brazing fin material for.
(A) One or both of In: 0.3% or less (not including zero), Sn: 0.3% or less (not including zero ) (b) Ti: 0.1% or less (not including zero) , Zr: 0.1% or less (excluding zero) or two types (2) Fe: more than 1.0% and 2.2% or less, Si: 0.5 to 1.5% and Mn: 0.4 to 1.3% is contained as an essential component, and as a selective component, Zn is 3.0% or less, and one or more elements of the element group represented by the following (a) and (b) In the range of 300 ° C. to 480 ° C., the final intermediate annealing is carried out at a cooling rate of 10 ° C./second or more of the molten metal, and the thickness is 0.1 mm or less. 80% or more of the surface area seen from the surface layer formed by recrystallizing the aluminum alloy by the annealing is performed in the rolling direction The rolled material having a crystal structure that is occupied by recrystallized grains with a diameter of greater than or equal to the length 10 mm, brazing fin material, characterized by being manufactured performs rolling reduction of 30% or less of the final cold rolling.
(A ) One or both of In: 0.3% or less (not including zero), Sn: 0.3% or less (not including zero ) (b) Ti: 0.1% or less (not including zero) , Zr: one or two of 0.1% or less (excluding zero) .

  In the present invention, by defining the alloy composition, manufacturing process, and crystal structure, it is possible to improve the characteristics of the fin material that is becoming thinner. Specifically, the fin material of the present invention requires the tensile strength after brazing addition heat, thermal conductivity (due to the pressure resistance and heat performance of the heat exchanger), the amount of droop ( Strength during heat exchanger assembly manufacturing), fin melt resistance (wax diffusion resistance), corrosion resistance, and corrugation formation can be improved. Furthermore, according to the present invention, these high-performance fin materials can be manufactured stably.

One embodiment of the present invention is the method for producing a brazing fin material of (1) above .

Another embodiment of the present invention is the brazing fin material of (2) above .

The reason why the composition of the aluminum (Al) alloy used for the fin material in the present invention is limited as described above will be described below.
Essential elements such as iron (Fe) and silicon (Si) are added for the purpose of improving the strength after brazing and coarsening the recrystallized grains by obtaining fine intermetallic compounds.
If the Fe content is 1.0 mass% or less, the strength is not sufficiently improved. If it exceeds 2.2 mass%, the crystallization phase becomes coarse even at the cooling rate specified in the present invention, and the nucleation site for recrystallization Therefore, the recrystallized structure becomes fine. Further, the corrosion resistance of the fin material is lowered. In view of the above effects, the Fe content is preferably in the range of more than 1.2 mass% and less than 1.8 mass%.

If the Si content is 0.2 mass% or less, the strength after brazing heat is insufficient. Moreover, when it exceeds 2.0 mass%, melting | fusing point of an alloy will fall, and when using as a brazing fin material, a fin material will buckle by spreading | diffusion of a brazing material . The Si content is 0.5 mass% or more and 1.5 mass% or less.

The fin material of the present invention further contains manganese (Mn) in order to further improve the strength after the brazing heat . Furthermore, nickel (Ni) may be contained. When Mn is added, the disperse phase that crystallizes changes to the Al—Fe—Mn—Si system, and the strength after heat of brazing addition is further improved. However, since excessive inclusion reduces the thermal conductivity of the fin material, the preferable upper limit of the Mn content is 1.3 mass%. When Ni is contained excessively, there is almost no influence that the thermal conductivity is lowered, but 1.3 mass% is the upper limit of the Ni content because the corrosion resistance is lowered.

Furthermore, the Al alloy constituting the fin material of the present invention may contain zinc (Zn) having a sacrificial anode effect in addition to the above essential elements. Further, one or more of indium (In) and tin (Sn), and / or copper (Cu), titanium (Ti), and zirconium (Zr) effective for improving the strength may be added. Addition of Zn, In and Sn, together with the provision of the sacrificial anode effect, deteriorates the self-corrosion resistance of the fin material itself. Therefore, the upper limit of each content is preferably Zn: 3.0 mass%, In: 0.3 mass%, Sn: 0.3 mass%. In addition, when Cu or Ti is added in a large amount, the heat conductivity, corrosion resistance, and sacrificial anode effect of the fin material after brazing are reduced in the case of Cu and Ti, and the rollability and fatigue characteristics are reduced in the case of Zr. Therefore, the upper limit of the preferable content when these elements are added is Cu: 0.25 mass%, Ti: 0.1 mass%, Zr: 0.1 mass%, respectively.
In addition to the elements described above, elements that further refine the compound (for example, chromium (Cr), cobalt (Co)) may be added to the fin material of the present invention. In that case, a preferable upper limit is 0.2 mass% from the viewpoint of the corrosion resistance and crystal structure control of the fin material.
The composition of the aluminum alloy used for the fin material of the present invention is composed of the balance of Al and inevitable impurities in addition to the above-mentioned elements.

Next, the conditions defined in the present invention in the manufacturing process will be described. By prescribing the cooling rate during casting as 10 ° C./second or more, the Al—Fe—Si intermetallic compound that becomes coarse when it has a high composition (Fe and Si in high concentration) is finely dispersed. is there. The fine dispersed phase can obtain a coarse recrystallized structure due to the effect of preventing the movement of grain boundaries during the final annealing, and at the same time, the strength of the fin material after brazing addition heat can be improved by dispersion hardening. The cooling rate is preferably 15 to 5 × 10 ³ ° C./second.

  The reason why the aluminum alloy is recrystallized by the final intermediate annealing is that the present invention mainly focuses on high-strength fins. The present invention is applicable to a material that can be easily cold-rolled, leveled, or slitted with a plate thickness of 0.1 mm or less without being recrystallized and made into an O material, for example, a fin material having a fin material strength of 170 MPa or less. The fin material can be easily manufactured without applying the manufacturing method. The present invention is suitable for a high-strength fin material that has a material strength of 170 MPa or more and is difficult to produce unless softened by intermediate annealing.

In the aluminum alloy having the composition defined in the present invention, fine intermetallic compounds are densely dispersed, so that the recrystallized grain size after the final intermediate annealing becomes coarse. The provisions relating to the crystal structure in the present invention are based on the knowledge obtained by the present inventors as a result of observing fin materials having various crystal grain sizes. That is, in a coarse recrystallized structure having a length of less than 10 mm in the rolling direction, the strength differs depending on each crystal orientation, so the flatness of the strip cannot be maintained, and control of the cold rolling rate, leveling, slitting line, etc. Threading becomes difficult. In order to maintain flatness, it is necessary that about 80% or more of the surface area has a coarse extended structure close to the fiber structure, for example, a substantially elliptical recrystallized grain.
In the present invention, the length of the diameter of the recrystallized grains occupying 80% or more of the surface area as viewed from the surface layer of the rolled material after the final intermediate annealing is 10 mm or more, preferably 10 to 80 mm in the rolling direction on the surface of the rolled material. More preferably, it is 10-40 mm.
In the present invention, the “surface area viewed from the surface layer” refers to the surface area as viewed from the surface perpendicular to the plate thickness direction (LT-ST surface), and the size (long) of the rolled material at that time The width and width) can be any number. It may be the product width subjected to slitting, or the entire rolling width before slitting. For convenience of measurement, the product width is preferable, but the result is the same regardless of the size.

The final intermediate annealing for recrystallizing the fin material is limited to a thickness of 0.1 mm or less. When annealing is performed with a thickness exceeding 0.1 mm, other requirements of the present invention However, when rolling to a final thickness of 0.1 mm or less, for example, 0.06 mm, a considerable amount of strain is accumulated, and the recrystallized structure becomes fine during brazing heat addition, resulting in erosion (erosion) of the brazing material. This is because it tends to occur. Moreover, the high-strength fin material in which a large amount of strain is stored has a high material strength, causes defects such as edge cracks, and deteriorates corrugate formability. In the present invention, since the final intermediate annealing is performed with a plate thickness close to the final plate thickness, it is possible to manufacture a fin material having a low final cold rolling rate and excellent in brazing material erosion resistance and productivity.
The final intermediate annealing at a plate thickness of 0.1 mm or less is performed at 300 ° C. to 480 ° C. to obtain the crystal structure defined in the present invention. In the present invention, a coarse recrystallized structure is obtained by a fine dispersed phase, and therefore the recrystallization temperature is generally higher than that of a normal aluminum alloy for fin materials. Therefore, the temperature range of 300 ° C. to 480 ° C. is higher than the annealing temperature for recrystallizing a normal aluminum alloy for fin material. If the temperature of the intermediate annealing is too low, the strength is not sufficiently reduced, so that the resulting fin material is inferior in formability, and if it is too high, the precipitated particles are coarsened, and the strength of the resulting fin material after the brazing heat is reduced. To do. Since the specific recrystallization temperature varies depending on the alloy composition and process, it is preferable to determine each recrystallization temperature after evaluating each recrystallization temperature. Moreover, since a coarse recrystallized structure may not be obtained in continuous annealing, it is preferable to perform batch annealing. The annealing time is not particularly limited, but may be performed in a general range of 30 minutes to 6 hours.

  When intermediate annealing other than final annealing is performed in a batch-type heating furnace, the temperature range is preferably 250 ° C. to 450 ° C. and a temperature at which recrystallization is not completed. If it is less than 250 ° C., the softening is insufficient and the cold rolling property is inferior, and cracks and the like occur. Moreover, when it is 450 degreeC or more, a precipitation phase will coarsen and it will be inferior to cold rolling property. Although the annealing time is not particularly defined, it is preferably 30 minutes to 4 hours. If it is less than 30 minutes, it is difficult to stabilize the temperature of the entire coil, and if it exceeds 4 hours, energy is wasted. When intermediate annealing is performed in a continuous heating furnace, the holding time is preferably 20 seconds or less within the annealing temperature range of 400 to 600 ° C.

In order to observe the crystal structure of the rolled material after the intermediate annealing, it is sufficient to immerse it in aqua regia and directly observe the surface of the plate material. Visual observation is sufficient to observe a coarse crystal structure as in the present invention. Since the crystal grains that are coarse in the rolling direction usually have only one or two crystal grains in the plate thickness direction, observation from the surface layer may be performed. The ratio of the recrystallized grains having a length of 10 mm or more in the rolling direction in the surface layer is 80% or more per surface area, and preferably 85 to 100%.
If the sample after the final intermediate annealing cannot be collected, the fin product may be observed. This is because, when the crystal structure is coarse due to the intermediate annealing, the crystal structure after rolling at a low rolling rate as defined in the present invention is almost equivalent.

Furthermore, it is possible to estimate the recrystallized structure before heating from the recrystallized structure after brazing. In order for the recrystallized grain size after brazing heat to be coarse as in the present invention, in view of normal brazing heat treatment conditions (about 600 ° C. × several minutes), the crystal structure before heating is a fiber structure, It can be limited to either a coarse recrystallized structure. Even if a fine recrystallized structure is heated by brazing, the heating time by brazing is not so long that it grows to 10 mm or more.
Furthermore, the shape of the crystal grain boundary differs between the structure recrystallized from the fiber structure and the structure recrystallized from the coarse recrystallized structure. That is, as shown in the photographs of the fin material crystal structure before and after brazing heating in FIGS. 1 to 4, the crystal grain boundaries recrystallized from the coarse recrystallized structure (FIGS. 1 and 2: Example of the present invention) are those from the fiber structure ( Compared with FIGS. 3 and 4: Comparative Example), it has a sawtooth shape. This is different from the case of recrystallization from the fiber structure, and the recrystallization driving force is reduced due to the reduction of strain by recrystallization once, and further the precipitation proceeds due to the high intermediate annealing temperature. This is because there are many dispersed particles that hinder movement. Paying attention to such a difference, the recrystallized structure before heating can be estimated from the recrystallized structure after brazing, and the recrystallized structure immediately after the intermediate annealing temperature can be estimated. 1-4, each upper stage shows before brazing and each lower stage after brazing, and the minimum scale of the scale is 1 mm in FIGS. 1 and 2 and 0.5 mm in FIGS. Further, the recrystallized grain size is measured by a major axis (rolling direction, left and right direction in the figure). In FIGS. 3 and 4, recrystallization is performed from the complete fibrous structure before brazing shown in the upper stage to the recrystallized structure after brazing shown in the lower stage, and the shape of the crystal grains changes greatly. On the other hand, in FIGS. 1 and 2, the recrystallized structure before brazing shown in the upper part is slightly expanded in the rolling direction in the figure after brazing shown in the lower part, and the anisotropic characteristics are weakened. However, the minor axis (width direction; vertical direction in the figure) of the crystal structure becomes thick and recrystallization occurs, but the crystal grain boundary in a sawtooth shape is maintained. That is, after brazing, a recrystallized structure as shown in FIGS. 1 and 2 (a structure in which coarse sawtooth recrystallized grains having a diameter of 10 mm or more in the rolling direction occupy 80% or more of the surface area). If present, it can be assumed that the recrystallized structure after the intermediate annealing is the recrystallized structure defined in the present invention.

Except for the conditions specified above, a rolled material such as a coil can be made from an aluminum alloy by a conventional method.
In the present invention, the final cold rolling with a reduction rate of 30% or less is performed on the rolled material produced as described above to produce a brazing fin material. The rolling reduction is preferably 12 to 28%. Moreover, conditions other than a rolling reduction can perform cold rolling according to a normal condition.

  As described above, the fin composition produced by the alloy composition and manufacturing method according to the present invention has characteristics after brazing, in particular, high strength, thermal conductivity, corrosion resistance, resistance to brazing diffusion during brazing addition heat, and It is excellent in fin material productivity and corrugate formability that are easy to cold-roll when thin, leveling, slitting and the like.

Hereinafter, the present invention will be described in more detail based on examples.
Example (Invention Example)
Alloy No. shown in Table 1 An ingot obtained by melting an Al alloy having the composition of A and cooling the obtained molten metal at a cooling rate shown in Table 2 was continuously cast and rolled using a twin roll having a roll diameter of 880 mm in accordance with the manufacturing process shown in Table 2. The steel plate was cast into a plate-shaped ingot having a width of 1000 mm by the method and wound into a coil shape, which was then annealed and cold-rolled to obtain Example No. 1 fin material was manufactured. After the intermediate annealing, the maximum length of the recrystallized grains in the rolling direction as viewed from the surface layer was 18 mm, and the recrystallized grains of 10 mm or more occupied about 90% of the surface area. The cooling rate of the molten metal in the continuous casting and rolling method was determined by observing the ingot microscopically and measuring the dent light arm spacing.
Subsequently, the alloy No. shown in Table 1 was used. In place of B to F, the cooling rate of the molten metal and the production process are variously changed within the conditions prescribed in the present invention as shown in Table 2, and No. 2-6 fin materials were produced. No. In 1 to 6, the crystal structure after the final intermediate annealing and after the completion of rolling is macro-etched by immersing the surface of the Al alloy fin material 200 mm × 20 mm in aqua regia, the macro structure is observed, and the results are shown. It was shown in 2. In Table 2, the recrystallized structure in the surface layer is ◯ when 80% or more of the surface area is occupied by recrystallized grains having a diameter of 10 mm or more in the rolling direction, and △ when less than 80% and 60% or more. In the case of less than 60%, x is shown. The ratio of the recrystallized grains of 10 mm or more in the surface area was analyzed by using a macro-etched fin material surface image as an image in a computer and using an image analysis tool.

(Comparative Example 1)
As shown in Table 1, alloy No. Using Al alloys of G to K, using the production conditions shown in Table 2, No. 7-11 fin materials were produced. After the final intermediate annealing and after completion of rolling, the crystal structure was evaluated in the same manner as in the inventive examples. The results are shown in Table 2.

(Comparative Example 2)
As shown in Table 2, the production conditions of the fin material are outside the scope of the present invention. Nos. A to E are used. 12-16 fin materials were manufactured. After the final intermediate annealing and after completion of rolling, the crystal structure was evaluated in the same manner as in the inventive examples. The results are shown in Table 2.

(Test example)
No. manufactured in Example of the present invention, Comparative Example 1 and Comparative Example 2. The following evaluation tests were performed on 1 to 16 fin materials.
The drooping resistance was evaluated by horizontally supporting the fin material so that the length of the fin material was 50 mm, heating at 600 ° C. for 10 minutes, and measuring the amount of droop (mm) after heating.
Moreover, after heating the said fin material on brazing equivalent conditions (600 degreeC x 4 minutes), the tensile strength and the electrical conductivity were measured. The tensile strength was evaluated according to JIS Z 2241 and the electrical conductivity was evaluated according to JIS H 0505.
Here, the electrical conductivity is an index of thermal conductivity. When the electrical conductivity of the fin is improved by 5% IACS, the thermal efficiency of the heat exchanger is improved by about 1%.
On the other hand, the fin material formed into a corrugated shape was assembled to a tube material having a length of 100 mm, and a five-stage mini-core was produced by brazing. This mini-core was evaluated by examining the presence or absence of fin melting by micro observation. Evaluation of fin melting was performed based on the same standards as described in JP-A-2003-34851.
Further, it was evaluated whether or not it broke during cold rolling, and whether or not it was difficult or difficult to pass through in the leveling and slitting processes. About what could not be manufactured industrially, the remainder was cold-rolled into a fin material using a laboratory facility and tested. These test results are shown in Table 3.

As is clear from Table 3, the experiment No. which is an example of the present invention. In 2, 3, and 6, in the production process, none of them breaks during cold rolling, and the leveling and slitting lines pass through without any problem, and the fin material can be produced by forming into a corrugated shape. did it. Further, the fin material was excellent in droop resistance, had high tensile strength and electrical conductivity (heat conductivity) after brazing heat, and did not melt the fin.
On the other hand, no. 7 had a large amount of added Fe, so that the crystallization phase became coarse. Therefore, it broke during rolling. Moreover, since the nucleation site of recrystallization increased, the recrystallization became fine. As a result, the amount of drooping increased and fin melting occurred.
Conversely, no. No. 8 had a small amount of Fe and primary crystal Si was formed, so recrystallization was in the micron order. As a result, the drooping amount increased and fin melting occurred. Moreover, since the amount of Fe was small, both the tensile strength and the conductivity after the brazing heat were reduced.
No. No. 9 is No.9. Although the tensile strength was improved by adding Mn to 8, the electrical conductivity further decreased. Since Si was not a primary crystal but was dispersed as an Al—Mn—Si intermetallic compound, the crystal structure was coarsened, and the plate could not be passed through the leveling process. Fin melt resistance was improved.
No. No. 10 has a large amount of added Si. Similar to 8, primary Si was formed.
No. No. 11 had a small amount of Si, and the Al-Fe-based crystallized material became coarse and became a nucleation site for recrystallization. Therefore, the grain size after the intermediate annealing was 4 to 5 mm in the rolling direction. Furthermore, since the amount of Si was insufficient, the tensile strength after brazing addition heat decreased.
No. No. 12 had a low cooling rate during casting, so that the crystallization phase became coarse. Grain size was refined to several μm, and tensile strength and conductivity after brazing heat were also reduced.
No. No. 13 had a high final cold rolling rate. Therefore, when it was rolled to the fin material, the amount of internal strain was large and the number of recrystallization nucleation sites increased. As a result, the recrystallized structure at the time of brazing addition heat became fine, the drooping amount increased, and fin melting occurred. Moreover, due to the high cold rolling rate, the tensile strength of the fin material base plate before the brazing addition heat increased and broke during rolling.
No. No. 14 had a low final intermediate annealing temperature, no recrystallization occurred, and the fiber structure was maintained. No. As in the case of No. 13, the tensile strength of the fin material base plate before the brazing addition heat increased, and breakage occurred during rolling.
No. In No. 15, the final intermediate annealing temperature was too high, and a part of the intermetallic compound was dissolved in the matrix. As a result, both the tensile strength and conductivity after the brazing heat were reduced. Since the intermetallic compound with a small size preferentially dissolved in the matrix phase, the pinning effect of the grain boundaries did not work, and the recrystallized grains after the brazing heat were refined. For this reason, the amount of drooping increased and fin melting occurred.
No. In No. 16, the first intermediate annealing was performed by continuous annealing. This reduced the amount of strain inside the material and reduced the driving force for recrystallization during the second (final) intermediate annealing. Therefore, recrystallization did not occur and the fiber structure was maintained. The tensile strength of the fin material base plate before the brazing heat increased, and fracture occurred during rolling.

It is a photograph of an example of the crystal structure before and after brazing heating of the fin material of the present invention. It is a photograph of an example of the crystal structure before and after brazing heating of the fin material of the present invention. It is a photograph of an example of the crystal structure before and after brazing heating of the conventional fin material. It is a photograph of an example of the crystal structure before and after brazing heating of the conventional fin material.

Claims (2)

Fe: more than 1.0% and 2.2% or less (% indicating composition means “mass%”, the same applies hereinafter), Si: 0.5 to 1.5% and Mn: 0.4 to 1 comprises .3% as essential components, as optional components, contains one or two or more elements of the indicated element group with a 3.0% or less Zn, further following (a) and (b) The aluminum alloy consisting of the balance Al and unavoidable impurities is cast at a molten metal cooling rate of 10 ° C./second or more, and the final intermediate annealing performed at a plate thickness of 0.1 mm or less is performed in the range of 300 ° C. to 480 ° C., Rolling material formed by recrystallizing an aluminum alloy by annealing and having a crystal structure in which 80% or more of the surface area seen from the surface layer is occupied by recrystallized grains having a diameter of 10 mm or more in the rolling direction. 30% or less final cold rolling is performed. Method of manufacturing a Jingu for the fin material.
(A) One or both of In: 0.3% or less (not including zero), Sn: 3.0% or less (not including zero ) (b) Ti: 0.1% or less (not including zero) , Zr: 0.1% or less (excluding zero)
1 type or 2 types Fe: 2.2% greater than 1.0% or less, Si: 0.5 to 1.5% and Mn: includes 0.4 to 1.3% as essential components, as optional components, a Zn 3.0 % or less and, further contain one or more elements of the indicated element group by the following (a) and (b), an aluminum alloy and the balance Al and unavoidable impurities, cooling rate 10 of the molten metal Surface area seen from the surface layer formed by refining the aluminum alloy by performing final annealing in the range of 300 ° C. to 480 ° C., cast at a rate of 0.1 ° C./second or more and performed at a plate thickness of 0.1 mm or less. The rolling material having a crystal structure occupied by 80% or more of the recrystallized grains having a diameter of 10 mm or more in the rolling direction is manufactured by subjecting to a final cold rolling with a reduction rate of 30% or less. Brazing fin material.
(A) One or both of In: 0.3% or less (not including zero), Sn: 3.0% or less (not including zero ) (b) Ti: 0.1% or less (not including zero) , Zr: One or two of 0.1% or less (excluding zero)