JP4667065B2 - 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.

  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. If the grain size of the fin material is fine, creep deformation tends to occur at high temperatures, and the fins buckle during the brazing process, and the assembly strength of the heat exchanger often decreases. Patent Document 4 proposes a fin material excellent in strength after brazing, thermal conductivity, and self-corrosion 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 is not an appropriate rule for the assembly strength. 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, if 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 the possibility of fine grain size is very high.

  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, a large amount of strain remains in the material having a rolled structure up to the brazing heat, and the strength of the material may be increased. 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. Further, when the strength of the material is high, cracks occur from the edge and the like, and there is a problem that the coil breaks during rolling with a thin wall.

As described above, thinning the fin material not only has excellent properties such as strength after brazing heat addition, thermal conductivity, corrosion resistance, and assembly strength during brazing, but also has rolling properties for stable production. It is necessary to consider productivity from the viewpoint of materials.
Japanese Patent Laid-Open No. 7-216485 JP-A-8-104934 International Publication WO00 / 05426 Pamphlet JP 2002-256402 A JP 2002-241910 A

  An object of the present invention is to provide a fin material for brazing excellent in strength, heat conductivity, self-corrosion resistance, and corrugating ability after brazing heat, and a production method capable of stably producing the fin material.

The present invention
(1) Fe exceeding 1.2 mass% and 1.8 mass% or less, Si exceeding 1.2 mass% and 2.0 mass% or less, Mn exceeding 0.3 mass% and 0.9 mass% or less, the balance being Al and inevitable 80% or more of the surface area seen from the surface layer has a diameter of 10 mm or more in the rolling direction after the intermediate annealing that is finally performed at a sheet thickness of 0.1 mm or less without annealing before intermediate annealing. A brazing fin material produced by cold rolling an aluminum alloy having a crystal structure occupied by recrystallized grains at a sheet thickness reduction of less than 30%;
(2) Fe exceeding 1.2 mass% and 1.8 mass% or less, Si exceeding 1.2 mass% and 2.0 mass% or less, Mn exceeding 0.3 mass% and 0.9 mass% or less , (a) 3. Zn of 0 mass% or less, In of 0.3 mass% or less, 1 type or 2 types or more of Sn of 0.3% mass or less, and / or (b) Cu of 0.25 mass% or less, 0.1 mass% or less One or more of Ti, 0.1 mass% or less of Zr, and / or (c) one of 0.2 mass% or less of Ni, 0.2 mass% or less of Cr, or 0.2 mass% or less of Co or 2 or more, it alloys der compositions the balance of Al and inevitable impurities, without performing annealing before intermediate annealing, after the intermediate annealing carried out at the end at the plate thickness 0.1mm or less, the table as viewed from the surface layer And characterized in that more than 80% of the product has been produced by cold rolling an aluminum alloy having a crystal structure that is occupied by recrystallized grains with a diameter of more than a length of 10mm in the rolling direction in the sheet thickness reduction rate less than 30% Fin material for brazing,
(3) The last intermediate annealing is performed at 300 to 480 ° C. for 30 to 1500 minutes, the brazing fin material according to (1) or (2),
(4) Fe in excess of 1.2 mass% and 1.8 mass% or less, Si in excess of 1.2 mass% and 2.0 mass% or less, and Mn in excess of 0.3 mass% and 0.9 mass% or less, the balance being Al and An aluminum alloy composed of inevitable impurities is subjected to final intermediate annealing at a thickness of 0.1 mm or less without annealing before intermediate annealing, and 80% or more of the surface area seen from the surface layer is 10 mm or more in length in the rolling direction. A method for producing a brazing fin material, characterized by having a crystal structure occupied by recrystallized grains having a diameter of, and then cold rolling at a sheet thickness reduction of less than 30%,
(5) Fe exceeding 1.2 mass% and not more than 1.8 mass%, Si exceeding 1.2 mass% and not more than 2.0 mass%, Mn exceeding 0.3 mass% and not more than 0.9 mass% , (a) 3. Zn of 0 mass% or less, In of 0.3 mass% or less, 1 type or 2 types or more of Sn of 0.3% mass or less, and / or (b) Cu of 0.25 mass% or less, 0.1 mass% or less 1 type or 2 types or more of Ti, 0.1 mass% or less of Zr, and / or (c) 1 type of 0.2 mass% or less of Ni, 0.2 mass% or less of Cr, and 0.2 mass% or less of Co Alternatively, an alloy having a composition of two or more , with the balance being Al and inevitable impurities , is subjected to final intermediate annealing at a thickness of 0.1 mm or less without annealing before intermediate annealing, and the surface area as seen from the surface layer The brazing fin is characterized in that 80% or more of the steel has a crystal structure occupied by recrystallized grains having a diameter of 10 mm or more in the rolling direction, and is then cold-rolled at a sheet thickness reduction of less than 30%. Manufacturing method of the material, and
(6) The method for producing a brazing fin material according to (4) or (5), wherein the final intermediate annealing is performed at 300 to 480C for 30 to 1500 minutes. is there.

  In the present invention, the characteristics of the fin material that is becoming thinner can be improved. Specifically, the amount of droop (strength when manufacturing heat exchanger assembly), self-corrosion resistance and corrugation formation necessary for thinning can be improved, and tensile strength and thermal conductivity after brazing heat can be improved. . Furthermore, this invention can manufacture these high performance fin materials stably.

One embodiment of the invention includes Fe greater than 1.2 mass% and less than 1.8 mass%, Si greater than 1.2 mass% and less than 2.0 mass%, Mn greater than 0.3 mass% and less than 0.9 mass%. In addition, the balance is made of Al and inevitable impurities, and 80% or more of the surface area viewed from the surface layer is length in the rolling direction after the final annealing at the plate thickness of 0.1 mm or less without annealing before the intermediate annealing. A brazing fin material manufactured by cold rolling an aluminum alloy having a crystal structure occupied by recrystallized grains having a diameter of 10 mm or more at a sheet thickness reduction of less than 30%.

In another embodiment of the present invention, Fe is more than 1.2 mass% and less than 1.8 mass% Fe, Si is more than 1.2 mass% and less than 2.0 mass%, and more than 0.3 mass% and 0.9 mass%. The aluminum alloy consisting of the following Mn , the balance being Al and inevitable impurities , is subjected to final intermediate annealing at a sheet thickness of 0.1 mm or less without annealing before intermediate annealing, and more than 80% of the surface area seen from the surface layer Is a method for producing a brazing fin material that has a crystal structure occupied by recrystallized grains having a diameter of 10 mm or more in the rolling direction and then cold-rolls at a sheet thickness reduction of less than 30%.

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.
In the present invention, an Al-Fe-Mn-Si intermetallic compound is finely dispersed, and it is an object to obtain a coarse recrystallized structure due to the effect of preventing dislocations and movement of subgrain boundaries during intermediate annealing. . The inclusion of essential elements such as iron (Fe), silicon (Si), and manganese (Mn) is aimed at improving the strength after brazing of the fin material and obtaining a fine intermetallic compound to increase the recrystallization coarseness. It is common in the point to do. Hereinafter, each element will be described in detail.

  The inclusion of Fe can further prevent the second phase dispersed particles from being an Al—Fe—Mn—Si intermetallic compound and prevent the dispersed particles from re-dissolving in the matrix phase by brazing to lower the thermal conductivity. Is the purpose. When the Fe content is 1.2 mass% or less, the strength is not sufficiently improved. When the Fe content exceeds 1.8 mass%, the crystallization phase becomes coarse and the recrystallization nucleation sites increase, resulting in a fine recrystallized structure. . Further, the corrosion resistance of the fin material is lowered. From the above effect, the Fe content is preferably in the range of more than 1.3 mass% and less than 1.7 mass%.

  When the Si content is small, most of the intermetallic compounds are Al-Mn compounds. Although this compound is fine and effective for coarsening of recrystallization during heating, most of it is re-dissolved in the matrix by the heat of brazing, so that the strength after brazing is reduced. In order to sufficiently obtain the strength after brazing, the effect is insufficient when the Si content is 1.2 mass% or less. Moreover, when it exceeds 2.0 mass%, the melting point of the alloy decreases, and when used as a brazing fin material, the fin material not only buckles due to diffusion of the brazing material, but also primary crystal Si is generated, and rolling in a thin wall The properties are significantly impaired. For the above reasons, the Si content is more preferably in the range of more than 1.2 mass% and 1.6 mass% or less.

  When the content of Mn is 0.3 mass% or less, the ratio of the Al—Fe—Si intermetallic compound in the second phase dispersed particles increases. Since the Al—Fe—Si intermetallic compound is coarser than the Al—Fe—Mn—Si, the recrystallized structure is not sufficiently coarsened. Also, the strength after brazing heat cannot be sufficiently improved. On the other hand, if the Mn content exceeds 0.9 mass%, the thermal conductivity and the rollability deteriorate. From the above reason, it is preferably in the range of more than 0.4 mass% and less than 0.8 mass%.

The Al alloy constituting the fin material of the present invention includes one or more of zinc (Zn), indium (In), and tin (Sn) having a sacrificial anode effect in addition to the essential elements described above. Alternatively, and / or one or more of copper (Cu), titanium (Ti), and zirconium (Zr) effective for strength improvement 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 value 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, nickel (Ni), chromium (Cr), cobalt (Co)) may be added to the fin material of the present invention. In that case, the upper limit of the preferable content from the viewpoint of the corrosion resistance of the fin material and the control of the crystal structure is 0.2 mass%.
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 reason why the crystal structure after the final annealing performed in the present invention is specified will be described. Since the present invention is mainly intended for high-strength fins, it is essential to recrystallize by intermediate annealing. A material having a thickness of 0.1 mm or less without being recrystallized to easily perform cold rolling, leveling, and slitting, for example, a fin material having a fin material strength of 170 MPa or less is used in the present invention. The fin material can be easily manufactured without applying the manufacturing method. On the other hand, 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 manufacture 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 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 order to obtain this rolled material, for example, an Al alloy having the above composition is produced into a plate-shaped ingot having a thickness of 2 to 9 mm at a casting speed of 500 to 3000 mm / min by a twin roll continuous casting rolling method. Rolling to a sheet thickness of 0.1 mm or less under the conditions of cold rolling, the final intermediate annealing at 300 to 480 ° C. for 30 to 1500 minutes may be performed. If the temperature of the intermediate annealing is too low, the strength is not sufficiently lowered, so that the formability of the obtained fin material is inferior, and if it is too high, the precipitated particles are coarsened and the strength of the obtained fin material after brazing heat is lowered. To do.
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 be performed at a plate thickness of 0.1 mm or less, and when annealing is performed at a plate thickness of more than this, even if the other requirements of the present invention are satisfied, This is because rolling to a final thickness of 0.1 mm or less, for example, 0.06 mm, accumulates a considerable amount of strain and makes the recrystallized structure fine during brazing addition heat. In addition, a high-strength fin material in which a large amount of strain is stored has a high material strength and causes defects such as edge cracks. The purpose of the present invention is to produce a fin material having a low final cold rolling rate and excellent heat exchanger assembly strength and productivity at the time of brazing, so the final intermediate annealing is a plate close to the final thickness. Do it in thickness. In the present invention, the aluminum alloy is manufactured into a brazing fin material by cold rolling after the final intermediate annealing. The reason why the cold rolling rate at that time is specified to be less than 30% is also a heat exchanger. This is to prevent the cracking strength at the time of rolling. The sheet thickness reduction ratio (cold rolling ratio) in the cold rolling after the final intermediate annealing is preferably 12 to 28%.

  In order to observe the crystal structure of the fin material after the intermediate annealing, the obtained alloy fin material may be immersed in aqua regia and the plate material surface may be directly observed. Visual observation is sufficient to observe a coarse crystal structure as in the present invention. The crystal grains that are coarse in the rolling direction usually have only one or two crystal grains in the plate thickness direction, and therefore observation from the surface layer may be performed. In the present invention, the proportion of recrystallized grains having a diameter of 10 mm or more in the rolling direction of the surface area viewed from the surface layer is 80% or more, preferably 85 to 100%. If the sample after the intermediate annealing cannot be collected, the fin product may be observed. This is because when a coarse crystal structure is formed by intermediate annealing, the crystal structure after rolling at a low rolling rate as in the specified range of the present invention is almost the same.

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. Moreover, 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 crystal structure of the fin material before and after brazing heating in FIGS. 1 and 2, the grain boundaries recrystallized from the coarse recrystallized structure (FIG. 1 : Reference Example 1 ) are those from the fiber structure (FIG. 2). : Compared with Reference Example 2 ), 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. In FIG. 1, 2, each upper stage before brazing, each lower indicates after brazing, the minimum scale of the scale in FIG. 1 1 mm, a 0.5mm in FIG. Further, the recrystallized grain size is measured by a major axis (rolling direction, left and right direction in the figure). In FIG. 2 , it recrystallizes 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. In contrast, in the FIG. 1, the before brazing recrystallized structure shown in the upper part in the figure after brazing as shown in the lower part by enlargement slightly extended in the rolling direction, and characteristics of the anisotropic weakens 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 the brazing, if recrystallized structure as shown in FIG. 1 (tissue coarse serrated recrystallized grains having a size of at least a length of 10mm in the rolling direction is 80% or more of the surface area) It can be presumed that the recrystallized structure after the intermediate annealing is the recrystallized structure defined in the present invention.
In the present invention, except for the conditions described above, the fin material can be appropriately produced using a conventional method.

  As described above, the fin material manufactured from the aluminum alloy defined in the present invention is excellent in characteristics after brazing, particularly strength and assembly strength during brazing heat. Moreover, the cold rolling property, leveling, slitting, etc. in the thin wall when manufacturing into the fin material can be manufactured without problems.

The present invention will be described in detail below with reference to examples.
Example (Invention Example)
The Al alloy no. 1 is melted, and the resulting molten metal is cast into a plate-shaped ingot having a width of 1000 mm at a cooling rate of 1000 mm / min by a continuous casting and rolling method using a twin roll having a roll diameter of 880 mm, and wound into a coil shape. The final intermediate annealing was performed at 400 ° C. for 120 minutes with a plate thickness of 0.1 mm or less. After the intermediate annealing, the maximum length of the diameter in the rolling direction of the recrystallized grains as seen from the surface layer was 18 mm by macro observation described later, and the recrystallized grains of 10 mm or more occupied about 90% of the surface area. . Next, this was cold-rolled at a sheet thickness reduction of 20% to produce the fin material of Inventive Example 1. In the same manner, the Al alloy no. The fin materials of Invention Examples 2 to 5 were produced using 2 to 5, respectively.

(Comparative example)
Table 1 shows an Al alloy no. The fin material of Comparative Examples 6-11 was manufactured similarly to Example 1-5 of this invention except having used 6-11, respectively.
In addition, the alloy no. 1 was used, but the fin material of Comparative Example 12 was manufactured in the same manner as Examples 1 to 5 except that the intermediate annealing was changed to 280 ° C. and 600 minutes.

(Test example)
About the fin material of the example of the present invention and the comparative example, it was evaluated whether or not it broke during cold rolling, and whether or not it could not pass through in the leveling and slitting process. For those that could not be industrially manufactured due to the above manufacturing problems, the remainder was cold-rolled into a fin material using a laboratory facility and tested or evaluated. These tests and evaluation results are shown in Table 2.
In Table 2, the presence or absence of breakage during rolling is the presence or absence of breakage during the cold rolling.
Further, the crystal structure after final intermediate annealing and after completion of rolling was subjected to macro etching by immersing the surface of the Al alloy fin material 200 mm × 20 mm in aqua regia, and the macro structure was observed and evaluated. In Table 2, the recrystallized structure is ◯ when the recrystallized grains having a diameter of 10 mm or more in the rolling direction are 80% or more with respect to the surface area, and Δ, 60 when the recrystallized structure is less than 80% and 60% or more. When it was less than%, it was shown by x. 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.
Moreover, the following evaluation tests were conducted. The test results are shown in Table 2.
The fin material was heated under brazing equivalent conditions (600 ° C. × 4 minutes), and then the tensile strength and 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%.
In addition, sagging resistance was evaluated as an index of the strength of assembly of the heat exchanger. The drooping resistance was evaluated by measuring the drooping amount (mm) after heating by heating at 600 ° C. for 10 minutes, instructing the fin material horizontally so that the length was 50 mm. The self-corrosion resistance was evaluated by examining the weight loss rate after conducting a CASS test for 7 days.

  As is clear from Table 2, none of the fin materials of Invention Examples 1 to 5 breaks during cold rolling, and the leveling and slitting lines can be passed through without problems and manufactured into fin materials. And could be formed into a corrugated shape. The fin material was excellent in droop resistance and self-corrosion resistance, and had high tensile strength and electrical conductivity after brazing heat.

On the other hand, in Comparative Example 6, since the amount of added Fe was large, the crystallization phase was coarsened. As a result, the number of nucleation sites for recrystallization increased and the recrystallization was refined to several hundred μm. As a result, the drooping amount increased. Moreover, since the ratio of the Al—Fe—Si intermetallic compound in the second phase dispersed particles was increased, the self-corrosion resistance was lowered.
In Comparative Example 7, the amount of Fe was small and the amount of crystal precipitation of Mn and Si was decreased, so that the tensile strength and conductivity after brazing equivalent heating were lowered. Instead, primary crystal Si was formed, which became the core of recrystallization and the grain size was refined to several hundred μm. The amount of drooping increased due to the effects of primary Si and grain size.
In Comparative Example 8, since the amount of added Si was large and primary Si was generated, it became the core of recrystallization and the grain size was refined to 10 mm or less. As a result, flatness deteriorated and leveling could not be performed.
In Comparative Example 9, the amount of Si was small, and the Al-Fe-Mn-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.
Comparative Example 10 had a large amount of added Mn and broke during rolling. The fin material produced from the remaining portion had a reduced electrical conductivity after brazing equivalent heating.
In Comparative Example 11, since the amount of added Mn was small, most of the second phase dispersed particles were Al—Fe—Si intermetallic compounds. For this reason, self-corrosion resistance fell. In addition, since the Al-Fe-Si compound is coarser than the Al-Fe-Mn-Si intermetallic compound, it becomes a nucleation site for recrystallization, the recrystallization becomes fine, and the amount of drooping increases. . Moreover, the tensile strength after brazing equivalent heating fell.
In Comparative Example 12, there was no problem with fin characteristics during brazing and after brazing addition heat, but it was difficult to pass the plate due to deterioration of flatness in the leveling and slitting processes.

It is a photograph of an example of the crystal structure of the fin material of Reference Example 1 before and after brazing heating. It is a photograph of an example of the crystal structure before and after brazing heating of the fin material of Reference Example 2 .

Claims (6)

Fe of more than 1.2 mass% and 1.8 mass% or less of Fe, Si of more than 1.2 mass% and 2.0 mass% or less, Mn of more than 0.3 mass% and 0.9 mass% or less, the balance being Al and inevitable impurities Recrystallized grains in which 80% or more of the surface area viewed from the surface layer has a diameter of 10 mm or more in the rolling direction after the intermediate annealing finally performed at a sheet thickness of 0.1 mm or less without annealing before intermediate annealing. A brazing fin material produced by cold-rolling an aluminum alloy having a crystal structure occupied by a thickness of less than 30%. Fe exceeding 1.2 mass% and 1.8 mass% or less, Si exceeding 1.2 mass% and 2.0 mass% or less, Mn exceeding 0.3 mass% and 0.9 mass% or less , (a) 3.0 mass% or less Zn, 0.3 mass% or less of In, 0.3% or less of Sn or less of 0.3% or less, and / or (b) 0.25 mass% or less of Cu, 0.1 mass% or less of Ti, 0 1 type or 2 types or more of Zr of 1 mass% or less, and / or (c) 1 type or 2 types or more of Ni of 0.2 mass% or less, Cr of 0.2 mass% or less, Co of 0.2 mass% or less , What alloy der compositions the balance of Al and inevitable impurities, without performing annealing before intermediate annealing, after the intermediate annealing carried out at the end at the plate thickness 0.1mm or less, the surface area as viewed from the surface layer 8 Brazing characterized in that 0% or more is produced by cold rolling an aluminum alloy having a crystal structure occupied by recrystallized grains having a diameter of 10 mm or more in the rolling direction at a sheet thickness reduction of less than 30%. Fin material. The brazing fin material according to claim 1, wherein the final intermediate annealing is performed at 300 to 480 ° C. for 30 to 1500 minutes. Fe exceeding 1.2 mass% and not more than 1.8 mass%, Si exceeding 1.2 mass% and not more than 2.0 mass%, Mn exceeding 0.3 mass% and not more than 0.9 mass%, the balance from Al and inevitable impurities The final aluminum annealing is performed at a sheet thickness of 0.1 mm or less without annealing before the intermediate annealing, and 80% or more of the surface area seen from the surface layer has a diameter of 10 mm or more in the rolling direction. A method for producing a brazing fin material, characterized by having a crystal structure occupied by the recrystallized grains, and then cold rolling at a sheet thickness reduction of less than 30%. Fe exceeding 1.2 mass% and 1.8 mass% or less, Si exceeding 1.2 mass% and 2.0 mass% or less, Mn exceeding 0.3 mass% and 0.9 mass% or less , (a) 3.0 mass% or less Zn, 0.3 mass% or less of In, 0.3% or less of Sn or less of 0.3% or less, and / or (b) 0.25 mass% or less of Cu, 0.1 mass% or less of Ti, 0 1 type or 2 types of Zr of 1 mass% or less, and / or (c) 1 type or 2 types of Ni of 0.2 mass% or less, Cr of 0.2 mass% or less, and Co of 0.2 mass% or less above, the alloy composition and the balance of Al and inevitable impurities, without performing annealing before intermediate annealing, carried out the final intermediate annealing at a thickness 0.1mm or less, the surface area as viewed from the surface layer 80 % Of the fin material for brazing characterized by having a crystal structure occupied by recrystallized grains having a diameter of 10 mm or more in the rolling direction and then cold rolling at a sheet thickness reduction of less than 30% Production method. 6. The method for producing a brazing fin material according to claim 4, wherein the final intermediate annealing is performed at 300 to 480 [deg.] C. for 30 to 1500 minutes.