JPH08327291A - Aluminum sheet for cross fin and manufacture thereof - Google Patents

Abstract

PURPOSE: To enable immediate adaptation to any molding process available as an aluminum sheet material for a cross fin of a heat exchanger by arranging a subgrain texture to have crystallized grains existing at the center of the thickness thereof and none in a surface layer across the thickness thereof. CONSTITUTION: A subgrain 1 texture is so arranged to have recrystallized grains 2 existing at the center of the thickness and none of the recrystallized grains in a surface layer across the thickness. In the composition by wt.%, the texture contains 0.15-0.8 of Fe, 0.001-0.02 of Ti and unavoidable impurities and Al for the rest. In the unavoidable impurities, Si is below 0.15%. The solid solubility of Fe is 30-100ppm and electrical conductivity is 59% IACS. Thus, a flange of a cross fin can be molded properly by either of a draw molding method, a compound molding method and a drawless molding method thereby eliminating the need for preparing a different aluminum sheet for each molding method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum thin plate for cross fins and a method for manufacturing the same, and provides a thin plate material for a cross fin of a heat exchanger, which can be immediately adapted to any forming method. The purpose is to produce a cross fin by simplifying the process control and the like because it is not necessary to prepare an aluminum thin plate material for each forming method.

[0002]

2. Description of the Related Art A heat exchanger comprises a passage pipe for a heat medium and a fin member which comes into contact with the heat passage pipe and releases the heat of the medium to the surrounding air, and is manufactured by various manufacturing methods. For example, there is a method in which a heat medium passage pipe and a fin material are joined by brazing, and those joined by this method are strong against vibration and the like and are used for manufacturing automobile radiators and the like.
Since the brazing filler metal is melted by heating at a similar temperature, there is a drawback that the cost becomes high. On the other hand, for heat exchangers installed in room coolers, refrigerators, etc., a method of joining the heat medium passage pipe and the fin member by a low-cost mechanical means is adopted instead of brazing joining. That is, the thickness of the fin material 1
This is a method in which a through-hole corresponding to the diameter of the heat medium passage pipe is opened in a thin plate of 0 to 150 μm, and the passage pipe is penetrated through the through hole to bring the heat medium passage pipe and the fin material into close contact with each other. Such a fin in which the passage pipe is in close contact therewith is called a cross fin, and such a cross fin has a required space, for example, 1 to 2 mm.
A large number of sheets are laminated with a certain distance between them to form a heat exchanger.

The through holes through which the heat medium passage tubes pass are formed so that the cross fins can be stacked at a distance from each other so that a brim having a rising fin stacking interval in the direction perpendicular to the fin surface is formed. In addition, the front end of the flange is provided so as to be curved outward so as to secure the fin interval. That is, the effect of the collar is to increase the coupling force between the passage tube and the cross fins and improve the heat transfer.

By the way, aluminum is used for the cross fin because of its good formability and heat conductivity. The typical method for producing a brim whose tip is curved outward as described above is as follows. There is a method like ~. A thin aluminum plate is drawn (drawing) with a diameter larger than the diameter of the passage tube and a height that is higher than that of the passage pipe. Then, a draw forming method in which piercing (burring) and burring (piercing) are performed to open a through hole through which the passage pipe passes, and then refraining (processing for bending the tip of the collar outward). First, a piercing and burring process is performed on an aluminum thin plate to open a through hole, and then an ironing process (ironing process) is performed in two steps to reduce the plate thickness and form the rising part of the tsuba, and then the flare process is performed. Molding method. Composite molding in which draw processing in the draw molding method is performed in 1 to 2 steps, then piercing and burring are performed to open through holes, and then ironing is performed to supplement the length that is insufficient for the rise of the brim, and then reflaring is performed. Law.

That is, in the above-mentioned draw forming method, a soft material has been applied as an aluminum thin plate because it is mainly drawn and requires ductility. On the other hand, the drawless molding method made it possible to apply a hard material by raising the collar by ironing, but to reduce die wear in the presence of volatile lubricating oil, draw and ironing The combined use of the composite moldability was developed.

[0006] However, aluminum is used as a material for such a cross fin because it has good thermal conductivity and excellent moldability.
No. 34 gazette discloses that an aluminum DC ingot is subjected to a homogenizing treatment, followed by hot rolling, and intermediate annealing to finely precipitate a solid solution element,
Then, the cell size of the dislocations generated by cold rolling was made fine, and the final grain refining treatment reduced the subgrains to an average grain size of 3 μm.
As a fine one having a size of m or less, a technique has been proposed in which the processing strain during the molding process is uniformly dispersed to prevent the occurrence of cracks during the molding process.

Further, Japanese Patent Publication No. 62-54180 discloses that
Continuously cast and roll an Al melt containing a specific amount and ratio of Fe and Si to form a solid solution of Fe and Si to improve the strength, and then anneal for 1 to 2 hours to impart fin formability and reduce strength. A technique for preventing this has been proposed. Further, Japanese Patent Laid-Open No. 5-230579 discloses a specific amount of Si, Fe, C.
After continuously cold-rolling the obtained cast plate, an Al melt containing u and Ti is continuously supplied and cast into a pair of rotating opposed cooling molds to disperse the alloy elements as a solid solution and partially as an intermetallic compound. A technique has been proposed in which refining annealing is performed to precipitate fine intermetallic compounds of Si, Fe, and Ti to impart high strength and fin formability as fine subgrains of the structure.

[0008]

In all of the above-mentioned prior arts, alloy elements are precipitated as a fine intermetallic compound so that the metal structure is uniformly made into a fine subgrain structure. In addition, the uniformly fine subgrain structure has a relatively small degree of work hardening, and during the draw fin forming process, deformation tends to concentrate at a portion where the mold abuts and a crack defect tends to occur. On the other hand, the recrystallized structure has a relatively high degree of work hardening, but it is liable to cause roughening on the free surface of plastic working, tend to be the starting point of crack generation during fin forming, and tend to exhibit crack defects. A metal structure in which grains are mixedly present has both a subgrain structure defect and a recrystallization structure defect, and likewise tends to exhibit cracking defects.

The draw molding method, the drawless molding method, and the composite molding method described above all have advantages and disadvantages, but the use of volatile lubricating oil in the processing of high-strength thin-walled materials has been a trend in recent years. It is desired that the aluminum material has workability applicable to any molding method. However, in response to such demands, none of these and the conventional techniques proposed and announced as described above have the disadvantage that they cannot appropriately respond promptly.

[0010]

DISCLOSURE OF THE INVENTION As a result of intensive studies for solving the above-mentioned problems, the inventors of the present invention have found that the central portion of the plate has recrystallized grains and the surface layer has no recrystallized grains. The present invention has been completed by finding that the aluminum thin plate having a composite structure made of a structure cancels out each defect and is suitable for the forming process of the cross fin, and any of draw forming, drawless forming and composite forming is performed. The present invention succeeds in providing a semi-rigid aluminum thin plate which is also applicable to the above, and has succeeded in obtaining a manufacturing method capable of obtaining a stable product thereof, and is as follows.

That is, the present invention is an aluminum thin plate for cross fins, characterized in that recrystallized grains are present in the central portion of the plate thickness, and the plate thickness surface layer has a sub-grain structure in which no recrystallized grains exist. And Fe: 0.15 to 0.8%, Ti:
0.001 to 0.02%, the balance consisting of inevitable impurities and Al, Si in the inevitable impurities is less than 0.15%, Fe solid solution amount is 30 to 100 ppm, and plate thickness Recrystallized grains are present in the center, and the plate surface layer has a sub-grain structure with no recrystallized grains, and the conductivity is 59% IA.
An aluminum thin plate for cross fins, which is CS or more.

Further, the ratio of the recrystallized grains existing in the center of the plate thickness is 1 to 30 in terms of the area ratio in the section along the rolling direction.
%, And the size of the recrystallized grains existing in the plate thickness central portion is 5 to 50 μm, and the layer thickness in the plate thickness central portion where the recrystallized grains are present is further characterized. The range is 1/4 to 3/4 of the total plate thickness,
The above-mentioned plate is an aluminum thin plate for cross fins, which is a continuously cast rolled material.

Fe: 0.15-0.8, preferably in wt%
%, Ti: 0.001 to 0.02%, the balance consisting of inevitable impurities and Al, and Si in the inevitable impurities is
Aluminum alloy continuous casting and rolling plate with less than 0.15%, solid solution amount of Fe is 30 to 100 ppm, recrystallized grains exist in the center of plate thickness, and plate thickness center where the recrystallized grains exist The layer thickness range of the part is 1/4 to 3/4 of the total plate thickness, and the other plate surface layers have a subgrain structure without recrystallization, and the electrical conductivity is 59% IACS or more. It is an aluminum thin plate for cross fins.

According to the present invention, as a method for stably obtaining the above-mentioned aluminum thin plate of the present invention,
Fe: 0.15 to 0.8% by weight, Ti: 0.001 to 0.02
%, With the balance consisting of unavoidable impurities and Al, and continuous casting of an aluminum alloy melt having Si in the unavoidable impurities of less than 0.15%, followed by cold rolling at a reduction rate of 95% or more. 4 at a temperature of 250-300 ℃
It is a method for manufacturing an aluminum thin plate for a cross fin, which is characterized by performing heat treatment annealing for not less than 10 hours and not more than 10 hours.
If the continuously cast slab is relatively thick, it may be hot rolled.

[0015]

[Function] Since the recrystallized grains are present in the central portion of the plate thickness and the plate surface layer is a composite thin aluminum plate having a subgrain structure without recrystallized grains, the entire plate has a uniform subgrain structure or a regrained structure. Compared to those with a crystalline structure, drawability, ironing and burring workability are averaged to be excellent. That is, when the entire plate has a uniform sub-grain structure as in the prior art at the time of draw processing, deformation is concentrated on the punch shoulder and crack defects are likely to occur, and recrystallized grains are also mixed on the plate surface. The metal structure is
Although it has the effect of diffusing the strain, it is recognized that the free surface is liable to cause rough skin, and it becomes a starting point of crack generation and is likely to exhibit crack defects. On the other hand, according to the present invention, when the composite structure as described above is used, it is possible to prevent the deformation from being concentrated at the punch shoulder portion, and also when the ironing process is performed, the composite structure according to the present invention as described above is used. Since the surface portion has a subgrain structure and the moldability is good, a sufficient rising portion can be formed on the collar, which is as good as the case where the entire plate has a uniform subgrain structure.

In the case of a metal structure in which recrystallized grains are present in the plate surface layer, the deformed structure is likely to be non-uniform on the ignited surface, which is a starting point of crack generation and is likely to exhibit crack defects. Further, a metal structure in which subgrains and recrystallized grains are mixed does not have an internal structure that prevents the progress of cracking, and thus similarly exhibits cracking defects. Reflaring is the last step,
Since the composite structure of the present invention has a subgrain structure and is easily deformed, it is good without cracking due to this reflare processing.

That is, if the whole plate has a uniform subgrain structure, the drawability is poor and it cannot be applied to the draw forming method and the composite forming method, and the whole plate has a uniform recrystallization structure and the subgrain structure. The metallographic structure having mixed recrystallized grains has poor draw workability and ironing workability and cannot be applied to the draw forming method, the drawless forming method and the composite forming method. Since the aluminum alloy sheet is good in draw processing, ironing processing and burring processing, it can be applied to any of the draw forming method, drawless forming method and composite forming method as an aluminum thin plate for forming cross fins.

The proportion of recrystallized grains existing in the center of the plate thickness of the thin plate of the composite structure of the present invention is 1 to 30% in terms of cross-sectional area ratio. By doing so, the surface of the surface during drawing and ironing Prevent the progress of deformation concentration. That is, if it is 1% or less, cracks on the punch shoulder cannot be prevented in draw processing, and if it is 30% or more, work hardening in the ironing processing becomes large, so that it may become a starting point of cracking during deformation, but these disadvantages do not occur. To process.

Further, in the composite structure thin plate of the present invention as described above, the size of the recrystallized grains in the plate center portion is set to 5 to 50 μm, whereby the concentration of surface deformation during draw processing and ironing processing is appropriately prevented. This recrystallized grain size is 5
If the recrystallized grains are less than 1 μm or less than 1% in the center of the plate thickness, it may not be possible to prevent the occurrence of cracks in the punch shoulder during the drawing process.
If the recrystallization ratio exceeding 30% is 30% or more, it may become a starting point of cracks during the flare processing after the drawless processing, but the processing can be performed without such a disadvantage.

In the composite structure thin plate according to the present invention, the thickness of the recrystallized layer in the central portion of the plate thickness is set in the range of 1/4 to 3/4 of the plate thickness so that the deformation on the surface during drawing and ironing Effectively prevent the progress of concentration. That is, when the ratio of recrystallized grains existing in a thin layer such as less than 1/4 or in the center of plate thickness is 1% or less in terms of cross-sectional area ratio, there is a possibility that surface deformation cannot be prevented from progressing inward. In a thick layer of 3/4 or more, when the recrystallized grain ratio is 30% or more in the cross-sectional area ratio, hardening by plastic working may cause cracking at the time of flare processing.
It can be processed without these fears.

The composite structure thin plate of the present invention has a composition of wt%.
Then, Fe: 0.15 to 0.8%, Ti: 0.001% or more to 0.0
Less than 2%, consisting of balance impurities, Si as unavoidable impurities of less than 0.15%, Fe solid solution amount of 30 to 100 pp
By setting m 2 and the electric conductivity to be 59% IACS or more, the strength can be improved, and a thin plate for a cross fin which has a high thermal conductivity and is preferable can be obtained. When the Fe content is less than 0.15 wt% and the Fe solid solution amount is less than 30 ppm, the strength after forming as a fin is low and it is difficult to apply as a thin plate material, and Fe is 0.8.
If it exceeds wt% and the solid solution amount of Fe exceeds 100 ppm, ductility may be insufficient and cracks may occur during the refiring process, or the electrical conductivity may be reduced. Ti content is 0.001 wt%
If the amount is less than the above range, there is a possibility that the grain refining during casting may be insufficient to cause casting cracks, and if the amount exceeds 0.02 wt%, the electrical conductivity may decrease. When the electric conductivity is less than 59% IACS, the thermal conductivity is lowered, and the performance as a heat exchanger may be impaired. As a typical impurity, Si is 0.15 wt% so as not to reduce the thermal conductivity, formability and corrosion resistance.
Less than Regarding impurities other than Si, Cu is 0.
Less than 15 wt%, Mn less than 0.03 wt%, Cr, V and Z
It is preferable that each of r is less than 0.015 wt%.

The composite structure thin plate of the present invention is preferably a rolled plate of a slab obtained by the continuous casting technique, since the solid solution amount of the alloy element increases and strength can be imparted.

The production of the composite structure thin plate of the present invention is not limited to the method described below, but preferred production methods include component composition, continuous casting and rolling conditions, and temper annealing. The explanation is as follows.

Fe: 0.15 to 0.8 wt% Fe is sufficiently solid-solved in continuous casting and rolling to give strength and fin formability, and is precipitated in the subsequent temper annealing and recrystallized in the center of the plate thickness. Grains are present in order to form a subgrain structure in which recrystallized grains do not exist in the plate surface layer. When the Fe content is less than 0.15 wt%, preferable strength cannot be imparted, and 0.8 wt %, A coarse intermetallic compound is generated to reduce the formability, and it is precipitated in the subsequent temper annealing to have recrystallized grains in the center of the plate thickness and no recrystallized grains in the plate surface layer. It cannot be a grain organization. A more preferable range of the Fe content is 0.7 wt% or less.

Ti: 0.001 wt% to 0.02 wt% Ti is contained in order to refine the crystal grains in continuous casting and prevent casting cracks. Ti content is 0.0
If it is less than 01 wt%, the above-mentioned effects will decrease, and 0.02 wt%
If it exceeds, the thermal conductivity is reduced and the entire thin plate becomes a fine subgrain structure, and recrystallized grains exist in the center part of the plate thickness after temper annealing, and recrystallized grains exist in the plate surface layer. Can not be a subgrain organization that does not exist. The preferable upper limit of the Ti content is less than 0.015 wt%. The addition of Ti is performed by Al-Ti master alloy or Al-Ti-
It is preferable to use a B master alloy. When an Al-Ti-B master alloy is used, B is contained, but the amount is 0.002 wt.
% Or less, the effect of the aluminum thin plate of the present invention is not impaired.

Inevitable Impurities As a typical impurity, 0.15 wt% of Si is used as a representative so as not to deteriorate the thermal conductivity, moldability and corrosion resistance.
Less than 0.15wt% Cu as other impurities
%, Mn is preferably less than 0.03 wt%, and each of Cr, V and Zr is preferably less than 0.015 wt%.

Continuous Casting and Rolling Conditions A continuous casting and rolling plate is a thin plate having a desired thickness obtained by cold rolling at a reduction rate of 95% or more without annealing the slab obtained by continuous casting. To do. This continuous casting and rolling is not limited as long as it can be rapidly solidified to cast a slab and continuously rolled. For example,
There is a water-cooled roll method in which molten aluminum is injected between a pair of internal cooling rotary rolls that are placed opposite to each other, and the cast slab is rolled without annealing.As another method, there is a space between a pair of rotary plates that cool the other side. There is a method in which a molten aluminum is poured into and the cast slab is rolled without annealing. The casting conditions are, for example, that the temperature of the molten metal is 680 to 730 ° C., the thickness of the slab is 70 mm or less,
It is preferably 50 mm or less, more preferably 30 mm or less. If it is 6 mm or less, it becomes difficult to realize a composite structure which is the object of the present invention. Slab pull-out speed is 50-150 cm /
Minutes.

Refining annealing 250 to 30 after cold rolling with a rolling reduction of 95% or more
A temper annealing treatment is performed at a temperature of 0 ° C. for 4 hours to 10 hours.
This treatment is a refining annealing treatment for imparting high strength to the thin plate, in which Fe and Ti are appropriately precipitated, and recrystallized grains are formed at 1/4 to 3/4 of the plate thickness at the center of the plate thickness. It exists in a proportion of 1 to 30% in terms of cross-sectional area ratio, and has a subgrain structure in other plate surface layers, and has a composite structure of these recrystallized grains and subgrain structure, and the solid solution amount of Fe is 30 to 30%.
This is because it is 100 ppm and the conductivity is 59% IACS or more. If the rolling reduction is less than 95% and the tempering annealing temperature is less than 250 ° C. and less than 4 hours, recrystallized grains as described above cannot be obtained. On the other hand, if the tempering annealing temperature exceeds 300 ° C., the area ratio of recrystallized grains increases too much, or the recrystallized grains become too large, which makes it difficult to obtain the preferable composite metal structure of the present invention. It is uneconomical to perform this tempering annealing for 10 hours or more.

[0029]

EXAMPLE A molten aluminum alloy having the compositions (wt%) of the alloy of the present invention, the comparative alloy and the conventional alloy as shown in Table 1 below was cast into a slab having a thickness of 7 mm by a water-cooling roll method and cold-rolled. Then, a thin plate having a thickness of 0.100 mm was prepared.

[0030]

[Table 1]

Each of the thin plates obtained as described above was subsequently subjected to temper annealing under the annealing conditions shown in Table 2 below, and the aluminum thin plates thus obtained were then draw-formed and composited, respectively. The results of evaluating the formability by forming a collar by molding and drawless molding are as shown in the latter part of Table 2. As another characteristic, Fe
The amount of solid solution, the electric conductivity, the plate thickness in the range where the recrystallized grains exist, the proportion of the recrystallized grains, and the mechanical properties were measured. The results are also shown in Table 2.

[0032]

[Table 2]

The evaluation and measurement conditions shown in Table 2 are as follows. * Formability of Tsuba: The formability of Tsuba is 100 for Tsuba by each of the following methods.
Although individually molded and evaluated by the occurrence of defects, a volatile press oil having a viscosity of 1.5 cSt (40 ° C.) was used as the lubricating oil used for molding. The final dimensions of the tsuba were all processed to an inner diameter of 9.9 mm. "Draw" fin pitch (flame height after reflaring) 1.
It was made 6 mm, subjected to a drawing process of 4 steps, and evaluated by the occurrence of punch shoulder cracks. Those without defects were reflared and evaluated by the occurrence of crack defects. The "drawless" fin pitch was set to 1.3 mm, and ironing was performed in two steps, and evaluation was made by the occurrence of color skipping. In addition, those without defects were subjected to reflaring and evaluated by the occurrence of crack defects. "Compound method" The fin pitch was 1.4 mm, the drawing process was performed in two steps, and then the ironing process was performed in two steps, and the occurrence of color jump was evaluated. Those without defects were reflared and evaluated by the occurrence of crack defects. * Fe solid solution amount: An aluminum thin plate was dissolved and filtered by the hot phenol method, and the filtrate was analyzed. * Electrical conductivity: Measured by the double-blitch method in an oil bath at 20 ° C (JIS H0505) * Plate thickness in the range where recrystallized grains exist: Anodizing treatment using a 1% aqueous solution of borofluoric acid and using an image analyzer It was measured. * Proportion of recrystallized grains: The proportion was measured with the same device as the above-mentioned plate thickness measurement. * Recrystallized grain size: The grain size was measured in the same manner as the measurement of the plate thickness and the ratio.

The conventional examples shown in Tables 1 and 2 are obtained by subjecting an alloy having the composition shown in Table 1 to DC casting to obtain a slab having a thickness of 580 mm and homogenizing it at 630 ° C. for 1 hour. The hot-rolled steel sheet had a thickness of 7 mm, and the cold-rolled steel sheet had a thickness of 0.100 mm. Further, this thin plate was subsequently subjected to temper annealing. The temper annealing conditions were as shown in Table 2. The aluminum thin plate thus obtained was provided with a collar to evaluate the formability. The evaluation method is the same as that of the above-mentioned embodiment, and the evaluation results are as shown in Table 2.

Regarding the evaluations ◯, Δ and × in Table 2, none of the evaluations were evaluated as ◯, a constriction occurred and a crack occurrence rate of 30% or less at the time of reflare processing was Δ, and punch shoulder cracking. Alternatively, x indicates that color flapping occurs and the crack occurrence rate during reflaring exceeds 30%, and the crack occurrence rate during reflaring is the result of the following equation. Punch shoulder cracking and collar jumping are phenomena in the previous stage in which the occurrence of necking leads to punch shoulder cracking or collar jumping.

According to the results of Table 2 as described above,
According to the present invention, the brim of the cross fin can be processed by any of forming methods such as draw forming, drawless forming and composite forming without causing defects such as constriction, punch shoulder crack, collar jump or reflaring crack. In contrast,
Draw forming for comparative alloy plate and conventional alloy plate,
It is clear that at least any one or more (and possibly all) of the drawless molding or the composite molding is inferior. Moreover, it is understood that the product according to the present invention is also excellent in conductivity and strength, and that a preferable product can be obtained by preparing the aluminum thin plate according to the method of forming the cross fins without using separate aluminum sheets.

[0037]

According to the present invention as described above, the brim of the cross fin can be appropriately formed by any of the draw forming method, the composite forming method and the drawless forming method. Since it is not necessary to prepare different aluminum thin plates, the process and other controls can be simplified, and a preferable cross fin can be produced easily at low cost, which is an industrially great invention.

[Brief description of drawings]

FIG. 1 is an explanatory view schematically showing a cross-sectional structure of an aluminum thin plate for a cross fin according to the present invention.

[Explanation of symbols]

 1 subgrain 2 recrystallized grains

Claims (8)

[Claims] 1. An aluminum thin plate for cross fins, wherein recrystallized grains are present in the center of the plate thickness, and the plate thickness surface layer has a sub-grain structure without recrystallized grains. 2. Fe: 0.15 to 0.8% and Ti: wt%
0.001 to 0.02%, the balance consisting of inevitable impurities and Al, Si in the inevitable impurities is less than 0.15%, Fe solid solution amount is 30 to 100 ppm, and plate thickness Recrystallized grains are present in the center, and the plate surface layer has a sub-grain structure with no recrystallized grains, and the conductivity is 59% IA.
An aluminum thin plate for cross fins, which is CS or more. 3. The ratio of recrystallized grains existing in the center of plate thickness is 1 to 30% in terms of area ratio in a cross section along the rolling direction, according to any one of claims 1 and 2. Aluminum thin plate for cross fins described. 4. The aluminum thin plate for a cross fin according to claim 1, wherein the size of the recrystallized grains present in the center of the plate thickness is 5 to 50 μm. 5. The layer thickness range of the central portion of the plate thickness where the recrystallized grains are present is 1/4 to 3/4 of the total plate thickness, according to any one of claims 1 to 4. Aluminum thin plate for cross fin. 6. The thin aluminum plate for cross fins according to claim 1, wherein the plate is a continuously cast rolled material. 7. In wt%, Fe: 0.15 to 0.8%, Ti:
An aluminum alloy continuous casting and rolling plate containing 0.001 to 0.02%, the balance being unavoidable impurities and Al, wherein Si in the unavoidable impurities is less than 0.15%.
e The solid solution amount is 30 to 100 ppm, recrystallized grains exist in the center of plate thickness, and the layer thickness range in the center of plate thickness where the recrystallized grains exist is 1/4 to 3/4 of the total plate thickness. The other plate surface layer has a sub-grain structure in which recrystallization does not exist, and has an electric conductivity of 59% IACS or more, and is an aluminum thin plate for cross fins. 8. Fe: 0.15 to 0.8% and Ti: 0.1% by weight.
001 to 0.02%, the balance consisting of unavoidable impurities and Al, and cold casting with a reduction rate of 95% or more after continuous casting of an aluminum alloy melt containing Si in the unavoidable impurities of less than 0.15% Roll and then 250-300
A method for producing an aluminum thin plate for a cross fin, which comprises performing temper annealing for 4 hours or more and 10 hours or less at a temperature of ° C.