JP2000351092A - Brazing sheet for heat exchanger and method for producing the same - Google Patents

Abstract

(57) [Summary] An Al-Si-Mg brazing material is used as a cladding material,
-Formability and brazing properties (erosion resistance) of a brazing sheet for heat exchangers formed by cladding a Mn-based alloy or an alloy obtained by adding at least one of Mg, Cu, Ti, and Si to the core. Both provide excellent things. SOLUTION: The brazing material is a complete O material, and the core material has a tempering degree of H24 or H22. Claim 2: The intermediate annealing in the middle of cold rolling after hot clad rolling is performed within the range of 260 to 450 ° C, and the average cooling rate to 200 ° C after intermediate annealing is 30 ° C / hour or less; Thereafter, final cold rolling is performed at a rolling reduction of 20 to 90%, and as final annealing, heating is performed at a temperature not lower than the recrystallization temperature of the brazing material and lower than the recrystallization temperature of the core material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy brazing sheet used for various heat exchangers, such as a heat exchanger for automobiles, and is particularly suitable for a molded plate for forming a refrigerant passage in a laminated evaporator. Further, the present invention relates to a brazing sheet having good moldability and brazing properties, and a method for producing the same.

[0002]

2. Description of the Related Art Brazing sheets comprising an aluminum alloy core material clad on one or both sides with an aluminum alloy brazing material have been used for various brazing structures. It is frequently used in Among the various types of heat exchangers, in the production of a laminated evaporator, in the state in which molded plates made of brazing sheets are superimposed, they are molded so that a refrigerant passage is formed between the molded plates. It is usual to assemble the evaporator by brazing after alternately combining the materials with each other. Therefore, as a brazing sheet for forming a refrigerant passage used in such a laminated evaporator, in addition to brazing properties, Formability for forming a refrigerant passage is also required. Therefore, for such an application, it is usual to use a brazing sheet having moldability as an annealed material, that is, a so-called O material.

In this type of brazing sheet, an Al—Si—Mg brazing material is used as a skin material, and an Al—Mn alloy or Al—M is used as a core material.
n-Mg based alloy, Al-Mn-Cu based alloy, Al-Mn
In many cases, Al-Mn-based alloys such as -Mg-Cu-based alloys are used. In the production, the skin material and the core material are compression-bonded by hot clad rolling to form a laminated plate, which is then cold-rolled to a required thickness, and further subjected to final annealing. It is usual to finish as. Here, in general, the standard annealing conditions for finishing the O material of the brazing sheet include:
For example, as shown in Table 1.6.3 on page 11 of “Aluminum Handbook (Fourth Edition)” (January 15, 1990) issued by the Japan Light Metal Association, “about 345 ° C., air cooling or Furnace cooling is recommended. When combining a laminating evaporator using such a brazing sheet finished with O material, vacuum brazing is generally applied as a brazing means.

[0004]

In the laminating type evaporator as described above, in the processing of forming a brazing sheet for forming a coolant passage, the degree of processing differs from part to part, and from the part where the processing degree is 0% to as much as 10% or more. Some parts reach a certain degree. In such a forming process, when a conventional so-called O material as described above is used, at a portion which has been processed by about 5%, the core material does not recrystallize even when the core material reaches the brazing temperature during brazing. In some cases, a phenomenon that the molten solder infiltrates the core material, that is, a so-called erosion may occur. When such erosion occurs, there is a problem that the brazing material to be accumulated in the joint portion is insufficient, resulting in a decrease in brazing properties, and also a problem that the corrosion resistance of the erosion generation site is reduced. Therefore, it is important to prevent the occurrence of erosion and improve the brazing property.

[0005] On the other hand, it is also known that if the refining of the brazing sheet is finished with H24 material instead of O material, erosion is greatly reduced. However, when finished to H24 material, there is a problem that the formability is greatly reduced, and there is a problem that a forming crack occurs at the time of manufacturing a laminated evaporator. Therefore, it is a fact that it is hardly used in actual operation.

The present invention has been made in view of the above circumstances, and provides a brazing sheet for a heat exchanger which is excellent in formability and also excellent in brazing properties and hardly causes erosion during brazing. It is intended for.

[0007]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have conducted intensive studies on conventional so-called O-material finishing brazing sheets.
In a conventional brazing sheet with a so-called O-material finish, the core portion is certainly in a completely annealed state (O-material), but the brazing material in the skin material portion has a precipitation hardened portion remaining in a part. It turned out to be in a state that could not be said to be a completely annealed material. That is, the brazing material of the skin material is A
Although it is an l-Si-Mg-based alloy and corresponds to a kind of heat treatment type alloy, it is generally only recognized as a brazing material, and the recognition that it is a heat treatment type alloy is insufficient. However, even in the annealing of a brazing sheet using such an Al-Si-Mg-based brazing alloy, it has been considered that the unstable intermediate phase causing precipitation hardening is sufficiently precipitated as a stable phase. In fact, the standard annealing conditions described in the aforementioned publication (about 34
(Furnace cooling or air cooling at 5 ° C.), it is not considered that the unstable intermediate phase is sufficiently positively precipitated as a stable phase in the brazing filler metal portion, and the completely annealed state is reliably and stably maintained. It was difficult to get. By the way,
In the above publication, as a comment on the standard annealing conditions of the brazing sheet, it is described that `` the cooling rate is not important ''. It is presumed that the deposition was not considered.

As described above, in the conventional so-called O-material brazing sheet, although the core material is in a completely annealed state, the brazing material in the skin material is often not completely annealed. However, even the brazing sheet in such a state has a level of formability that does not cause any particular problem in the forming process for assembling a formed plate for a heat exchanger such as a laminated evaporator.
From these facts, the present inventors have concluded that the brazing material, which is a skin material, is a completely annealed material, and the core material is a brazing sheet in a state of H24 finish or H22 finish excellent in erosion resistance. With the idea that it would be possible to secure excellent formability to the extent that there would be no particular hindrance to the forming of molded plates such as laminated evaporators, we conducted further experiments and studies based on that idea. As a result, they have found that the above-mentioned tempering combination can actually secure excellent moldability, and at the same time, can sufficiently exhibit erosion resistance, and have accomplished the present invention.

[0009] Specifically, the invention of claim 1 is an Al-S
A brazing material made of an i-Mg alloy is used as a cladding material, and Al-Mn
A brazing sheet for a heat exchanger comprising a base alloy or a base alloy obtained by adding at least one of Mg, Cu, Ti, and Si to a core material and cladding a cladding material on one or both surfaces of the core material, It is characterized in that the brazing material of the skin material is a complete O material and the core material is H24 or H22.

[0010] The invention of claim 2 is an Al-Si-Mg
A brazing material made of a base alloy is used as a cladding material, and an Al-Mn-based alloy or an alloy obtained by adding at least one of Mg, Cu, Ti, and Si to the core material is used as a core material, on one or both surfaces of the core material. In producing a brazing sheet for a heat exchanger formed by cladding a skin material, intermediate annealing in the middle of cold rolling after hot clad rolling is performed at a temperature in the range of 260 to 450 ° C, and after the intermediate annealing. The average cooling rate to 200 ° C. is 30 ° C./hour or less, the final cold rolling is performed at a rolling rate in the range of 20 to 90%, and the final annealing is performed at a temperature not lower than the recrystallization temperature of the brazing material and The heating is performed at a temperature lower than the recrystallization temperature of the core material.

Further, the invention according to claim 3 is a method for manufacturing a brazing sheet for a heat exchanger according to claim 2, wherein
The average cooling rate to 200 ° C. after the final annealing is set to 30 ° C./hour or less.

In the above description, the complete O material for the brazing material as a skin material is a softened material in which not only a work hardened portion but also a precipitation hardened portion caused by an unstable intermediate phase are completely eliminated by annealing. A state shall be designated. That is, since the Al-Si-Mg-based alloy used as the brazing filler metal is a heat-treatable alloy, an unstable intermediate phase is generated by undergoing thermal processing during hot rolling, thereby causing precipitation hardening. Usually, even if the work-hardened portion is annihilated by annealing, the precipitated hardened portion remains and usually does not enter a completely softened state. Therefore, the cooling rate in the annealing treatment is regulated, or a treatment corresponding to a so-called overaging treatment, such as holding at a specific intermediate temperature, is performed to precipitate an unstable intermediate phase as a stable phase, A material finished in a state in which the precipitation hardening component due to the intermediate phase is also eliminated is referred to as a complete O material. It should be noted that a state in which the work hardening has disappeared can be determined as a state in which the crystal grains are recrystallized 100%.

On the other hand, the H24 material for the core material is JIS
As defined in H 0001, a tempered state (H2Y
Temper showing the intermediate tensile strength between the one with tensile strength (H28 material) and the completely annealed material (O material) obtained when cold-working at a cross-section reduction rate of approximately 75%. The H22 material is in a tempered state showing an intermediate tensile strength between the H24 material and the O material.

Here, when the tempering degree of the core material is H26, the elongation is remarkably reduced and the formability is deteriorated. On the other hand, when the material is completely O, the case of a conventional general brazing sheet has already been described. As a result, erosion is likely to occur. Therefore, the core material needs to be H24 material or H22 material which is a refining material between the O material and the H26 material.

[0015] As described above, the brazing sheet of the temper combination in which the brazing material as the skin material is completely O material and the core material is H24 material or H22 material has good moldability and good erosion resistance. . The reason why a good formability can be ensured as a brazing sheet for molding even with such a tempering combination is considered as follows.

That is, in the conventional brazing sheet forming process called the so-called O material, the brazing material as the skin material cannot be said to be the complete O material even if the core material is a complete O material. Because of this condition, cracks may occur in parts with a very high degree of processing, but in that case, the cracks occur from the brazing material on the skin side, and the crack stops at the interface between the brazing material and the core material. It has been observed that the timber has not been reached.
On the other hand, in the case of the brazing sheet of the present invention, since the tempered state of the core material is changed from completely O material to H24 material or H22 material, the ductility of the core material itself is lower than that of the current brazing sheet. However, the brazing material, which is a skin material that controls cracking, is a perfect O material and its ductility is improved compared to the current material, so that the formability of the brazing sheet as a whole can be maintained at a good level. it is conceivable that.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, an Al-Si-Mg based alloy is used as a brazing filler metal. Here, the specific component composition of the Al—Si—Mg-based alloy as the brazing material is not particularly limited, but the Si content is 7 to 10%.
The content of Mg may be about 12 wt% and the content of Mg may be about 0.5 to 2.5 wt%. In addition, if necessary, one or two of Bi of 0.2 wt% or less and Be of 0.01 wt% or less may be contained. good. Practical examples of this type of Al-Si-Mg brazing alloy include 4004 alloy, 4104 alloy, 4008 alloy, and 4N04 alloy, but are not limited to these.

On the other hand, as the core material alloy, an Al-Mn alloy or an alloy in which one or more of Mg, Cu, Ti, and Si are further added thereto may be used. Here, the content of each component element is not particularly limited, but usually, Mn is 0.3 to 2.0 wt% and Mg is 0.1
To 1.0 wt%, Cu is 0.1 to 1.0 wt%, Si is 0.1 to 1.0 wt%, Ti is 0.01 to 0.3 wt%
Is appropriate.

Further, as the layer constitution of the brazing sheet, the skin material made of brazing material may be clad on only one side of the core material, or may be clad on both surfaces of the core material. Here, the clad ratio of the brazing material is usually preferably about 5 to 20% per side.

Next, the details of the method for producing a brazing sheet of the present invention will be described.

In manufacturing the brazing sheet of the present invention, the steps from hot clad rolling to obtaining a laminated plate may be performed in the same manner as in manufacturing a normal brazing sheet. For example, a brazing material alloy and a core material alloy for a skin material are each cast, and if necessary, a soaking treatment is performed, and each alloy material is formed to a predetermined thickness by hot rolling, or the surface is not subjected to hot rolling. Only the cutting is performed to make each alloy material a predetermined thickness, and then the respective plates are overlapped and hot clad rolling is performed.

The laminated sheet thus obtained is annealed as required, and then cold rolled to a required thickness. And in the middle of this cold rolling, 2
Intermediate annealing is performed at a temperature within the range of 60 to 450 ° C. This intermediate annealing is not only for improving the cold rolling property by softening or recrystallizing the material in the middle of cold rolling, but also for causing precipitation in the brazing material through the slow cooling process after the intermediate annealing. This is a necessary step. Here, if the intermediate annealing temperature is lower than 260 ° C., the effect of the precipitation treatment is not sufficient. On the other hand, if the intermediate annealing temperature exceeds 450 ° C., the precipitation is saturated, the oxidation becomes intense, and the use energy is wasted. The temperature was within the range of 450 ° C. The holding time at a temperature in the range of 260 to 450 ° C. in the intermediate annealing is not particularly limited, but is usually preferably about 0.5 to 5 hours.

The cooling rate in the cooling process after the intermediate annealing is an average cooling rate from the intermediate annealing temperature to 200 ° C.
Slow cooling at 0 ° C / hour or less. As described above, by gradually cooling the average cooling rate to 200 ° C. after the intermediate annealing at 30 ° C./hour or less, it becomes possible to sufficiently precipitate a stable phase of Mg ₂ Si from the brazing material. If the average cooling rate to 200 ° C. after the intermediate annealing exceeds 30 ° C./hour, precipitation of a stable phase during cooling is not sufficient, and it becomes difficult to finally turn the brazing material into a complete O material. Therefore, the average cooling rate to 200 ° C. after the intermediate annealing is 30 ° C. /
It is necessary to set the time to not more than an hour, but it is particularly preferable to be not more than 25 ° C./hour. 200 ° C. in the cooling process after intermediate annealing
Since the lower temperature range has little to do with the precipitation of the stable phase, the present invention specifies a cooling rate up to 200 ° C.

Further, in order to ensure the effect of precipitating a stable phase in the cooling process after the intermediate annealing as described above, it is preferable that the holding is performed in the cooling process after the intermediate annealing. The holding conditions in the cooling process after such intermediate annealing may be determined so that the cooling rate from the intermediate annealing temperature to 200 ° C. satisfies 30 ° C./hour or more as described above.
Usually, it is desirable to carry out the reaction at a temperature within the range of 200 to 280 ° C. for about 1 to 10 hours, and particularly at 260 ° C.
For 4 hours.

The rate of temperature rise during heating for intermediate annealing is not particularly important, and may be arbitrarily determined.

As described above, the cold rolling (final cold rolling) after the intermediate annealing and slow cooling is performed at a rolling rate within a range of 20 to 90%. If the rolling reduction of the final cold rolling is less than 20%, recrystallization during brazing is delayed, and Si in the brazing material is
Diffusion into the core material becomes large, and the amount of Si in the brazing material decreases. On the other hand, if the rolling ratio of the final cold rolling exceeds 90%, the plate thickness before cold rolling increases to 4 mm or more,
The number of passes of the cold rolling increases and the production efficiency deteriorates.

After final cold rolling to a required thickness, for example, about 0.5 mm, final annealing is performed. In this final annealing, it is necessary to heat and hold at a temperature higher than the recrystallization temperature of the brazing material as the cladding material and lower than the recrystallization temperature of the core material. By performing final annealing in such a temperature range, it is possible to obtain a brazing sheet in which the brazing material is a perfect O material and the core material is H24 or H22.

Here, the recrystallization temperature of the brazing material made of an Al—Si—Mg alloy is slightly different depending on the specific component composition, but is usually about 200 ° C., while the core material Al—Mn Based alloy or Mg, Cu, Ti,
The recrystallization temperature of the alloy to which one or more types of Si are added also varies depending on the added components, but is usually about 300 to 450 ° C. Therefore, for example, if the final annealing is performed at about 230 to 280 ° C., the brazing material will be recrystallized. As a result, the core material is not completely recrystallized but softened to some extent, and becomes a finished state of H24 or H22. The specific final annealing temperature depends on the specific composition of the brazing material,
What is necessary is just to determine according to the recrystallization temperature of a core material. The heating and holding time in the final annealing is not particularly limited, but is usually 0.5
About 5 hours is preferable. The rate of temperature rise for heating in the final annealing is not particularly important, and may be arbitrarily determined.

The cooling rate in the cooling process after the final annealing is preferably 30 ° C./average from the final annealing temperature to 200 ° C. Thus, after final annealing, 20
By gradually cooling the average cooling rate to 0 ° C. to 30 ° C./hour or less, the brazing material can be completely and stably
Material. That is, in the method of the present invention, as described above, the average cooling rate to 200 ° C. after the intermediate annealing is gradually cooled to 30 ° C./hour or less to precipitate a stable phase. Elements such as Si and Mg constituting the stable phase may partly re-dissolve during the final annealing. If the cooling rate after the final annealing is high, precipitation hardening due to an unstable intermediate phase caused by an element in the brazing material partially re-dissolved during the final annealing occurs in the cooling process after the final annealing, and complete It may be in a state that cannot be said to be the O material. On the other hand, if the cooling to 200 ° C. after the final annealing is gradually cooled at a rate of 30 ° C./hour or less, the cooling process after the final annealing functions as a kind of overaging even if the solid solution is partially re-dissolved in the final annealing. As a result, the partially re-dissolved element precipitates as a stable phase, and the precipitation hardened component is eliminated, so that the brazing filler metal can be reliably and stably made a complete O-material.

In actually assembling a heat exchanger such as a laminated evaporator using the brazing sheet obtained as described above, first, a molding process for forming a predetermined shape, for example, a refrigerant passage in the laminated evaporator is performed. A forming process for forming the heat exchanger may be performed, and then the heat exchanger may be assembled and brazed. It is desirable to apply a vacuum brazing method to this brazing.

[0031]

Example 1 Example 1 of Table 1 1 to No. 5 was used as a core material, and a brazing material (Al-
10% Si-1.3% Mg alloy), thickness 40mm
A 8.6 mm thick brazing alloy plate was superimposed on both surfaces of each core alloy plate, and hot clad rolling was performed by a conventional method to obtain a double-sided clad three-layer laminated plate. The thickness of this laminated plate is 2.6 mm, and the cladding ratio is 15% per side.
It is.

Next, the above-mentioned laminated sheet is subjected to primary cold rolling to a sheet thickness of 1.5 mm, and then to an intermediate annealing of 40 mm.
Hold at 0 ° C x 2 hours, average cooling rate 25 ° C
Per hour, and the temperature is kept at 260 ° C. for 4 hours, and then cooled to room temperature at an average cooling rate of 100 ° C./hour.
The thickness was 5 mm. Then, 270 ° C as final annealing
For 2 hours, and cooled to room temperature at an average cooling rate of 100 ° C./hour to obtain a brazing sheet.

For comparison, an example in which the final annealing was held at 400 ° C. × 2 hours without intermediate annealing and cooled to room temperature at 100 ° C./hour (Comparative Example 6), and similarly, the final annealing without intermediate annealing was performed at 270 ° C. × An example (Comparative Example 7) of holding for 2 hours and cooling to room temperature at 100 ° C./hour was also performed.

Here, in the present invention, the final annealing temperature of 270 ° C. was determined as follows. That is, for each core material alloy and the above-mentioned brazing material alloy shown in Table 1,
Hot rolling, primary cold rolling, intermediate annealing, and cold rolling were carried out alone without cladding in the same manner as described above to produce single sheet materials of 0.5 mm each. Each plate material made of the core material alloy and the plate material made of the brazing alloy were heat-annealed at various temperatures for 2 hours, and the tensile strength was examined. As a result, the results shown in Table 2 were obtained. Based on this, the heating softening curve shown in FIG. 1 was obtained. From the heating softening curve shown in FIG. 1, in any of the combinations of the core material alloys 1 to 5 and the brazing material alloy, if the temperature is 270 ° C., it is sufficiently higher than the recrystallization temperature of the brazing material alloy and the core material It was found that the temperature was sufficiently lower than the recrystallization temperature of the alloy, and that the final annealing temperature condition defined in the present invention was satisfied.

[0035]

[Table 1]

[0036]

[Table 2]

Each of the brazing sheets obtained as described above was press-formed into the shape of the molded product 1 shown in FIG. 2A, the formability was examined, and two press-formed products were further examined. As shown in (B) of FIG. 2, a vacuum brazing test was performed by superimposing, and the brazed portion was examined for the occurrence of erosion as a brazing property evaluation. Table 3 shows the results. The evaluation criteria for moldability are as follows. ◎: No molding crack, no wrinkle ○: No molding crack, slightly wrinkle ×: Molding crack

The brazing property evaluation criteria are as follows. ○: No erosion occurred X: Erosion occurred

[0039]

[Table 3]

As shown in Table 3, it was found that all of Examples 1 to 5 of the present invention had excellent moldability and good brazing properties (erosion resistance). On the other hand, it was found that in Comparative Example 7 in which the final annealing conditions were within the range specified in the present invention but no intermediate annealing was performed, the brazing property was good but the formability was poor. In Comparative Example 6 in which the intermediate annealing was not performed and the final annealing temperature was too high, although the moldability was good, the brazing property was poor and erosion occurred.

Example 2 A 3003 alloy (Al-1.1% Mn) was used as a core material, and a brazing material (4004 alloy; Al-
10% Si-1.3% Mg alloy), thickness 40mm
A 8.6 mm thick brazing alloy plate was superimposed on both surfaces of each core alloy plate, and hot clad rolling was performed by a conventional method to obtain a double-sided clad three-layer laminated plate. The thickness of this laminated plate is 2.6 mm, and the cladding ratio is 15% per side.
It is.

Next, the above-mentioned laminated sheet is subjected to primary cold rolling to a sheet thickness of 1.5 mm, and then to an intermediate annealing of 40 mm.
Hold at 0 ° C x 2 hours, average cooling rate 25 ° C
/ Hour, and kept at the temperature of 260 ° C. for 4 hours, and then cooled to room temperature at an average cooling rate of 25 ° C./hour.
mm. Thereafter, as final annealing, heating and holding were performed at 310 ° C. for 2 hours. After cooling to 200 ° C. at an average cooling rate of 25 ° C./hour, cooling to room temperature was performed at a cooling rate of 100 ° C./hour to obtain a brazing sheet. For comparison, Comparative Example 9 in which the heating and holding temperature of the intermediate annealing was the same, the subsequent cooling rate was changed to 100 ° C./hour, the final annealing temperature was changed to 400 ° C., and the subsequent cooling rate was 100 ° C./hour. Comparative Example 10 in which the heating and holding temperature of the intermediate annealing was the same and the subsequent cooling rate was changed to 100 ° C./hour.
Was also implemented.

In this case, the recrystallization temperature of the core material alloy is about 390 ° C., and the recrystallization temperature of the brazing material alloy is 200
It is around ° C.

Each of the brazing sheets obtained as described above was examined for press formability and brazing properties (erosion resistance) in the same manner as in Example 1.
Were obtained.

[0045]

[Table 4]

As shown in Table 4, in the case of Inventive Example 8, both moldability and brazing properties (erosion resistance) were good. On the other hand, Comparative Example 1 in which both the cooling rate after the intermediate annealing and the cooling rate after the final annealing were as high as 100 ° C./hour.
At 0, the brazing properties were good, but the moldability was poor. In Comparative Example 9 in which the average cooling rate after the intermediate annealing and the average cooling rate after the final annealing were both as high as 100 ° C./hour and the heating temperature in the final annealing was as high as 400 ° C., the moldability was good, but the wax was good. It turned out to be inferior.

[0047]

According to the brazing sheet of the present invention, the brazing material as the skin material is completely made of O material and the tempering of the core material is made of H.
By using 24 or H22, the moldability is excellent, and at the same time, the brazing property is excellent and the erosion is less likely to occur during brazing. Therefore, the brazing molding used in a laminate type evaporator and other heat exchangers is used. Suitable for plate applications.

[Brief description of the drawings]

FIG. 1 is a graph showing a heating softening curve of each core alloy and brazing alloy used in Example 1.

FIGS. 2A and 2B are diagrams for explaining a moldability test in Examples, in which FIG. 2A is a perspective view showing the shape of a molded product, and FIG.
FIG. 3 is a longitudinal sectional view showing a state in which a pair of molded products are overlapped for brazing.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C22C 21/00 C22C 21/00 JL C22F 1/04 C22F 1/04 BC C F28F 21/08 F28F 21/08 A / / C22F 1/00 627 C22F 1/00 627 630 630M 651 651A 685 685Z 686 686B 692 692A 693 693A 694 694A

Claims (3)

[Claims] 1. A brazing material made of an Al—Si—Mg alloy is used as a cladding material, and an Al—Mn alloy or Mg, C
A brazing sheet for a heat exchanger in which one or more of u, Ti, and Si are added as a core material and a cladding material is clad on one or both surfaces of the core material, wherein the brazing material of the cladding material is completely O material and the core material is H2
A brazing sheet for a heat exchanger, which is excellent in moldability and brazing properties, characterized in that it is 4 or H22. 2. A brazing material made of an Al—Si—Mg alloy is used as a cladding material, and an Al—Mn alloy or Mg, C
In producing a brazing sheet for a heat exchanger, in which one or more of u, Ti, and Si are added as a core material and a cladding material is clad on one or both surfaces of the core material, hot clad rolling is performed. Intermediate annealing in the middle of cold rolling
The temperature is in the range of 60 to 450 ° C., and the average cooling rate to 200 ° C. after the intermediate annealing is 30 ° C./hour or less, and the final cold rolling is performed in the range of 20 to 90%. For heat exchangers with excellent moldability and brazing properties, characterized in that the final annealing is performed at a temperature not lower than the recrystallization temperature of the brazing material and lower than the recrystallization temperature of the core material. Manufacturing method of brazing sheet. 3. The method for producing a brazing sheet for a heat exchanger according to claim 2, wherein the average cooling rate to 200 ° C. after the final annealing is 30 ° C./hour or less. A method for producing a brazing sheet for a heat exchanger having excellent attachment properties.