JP2005177827A - Method of producing brazing sheet excellent in strength and solder erosion resistance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of producing a brazing sheet excellent in strength and solder erosion resistance. <P>SOLUTION: Both the surfaces of an aluminum alloy core material having a composition containing 0.1 to 2.5% Mn and 0.05 to 0.3% Zr, and further one or two metals selected from 0.1 to 1.2% Si, 0.1 to 2.0% Mg and 0.05 to 1.2% Ni, and the balance Al with inevitable impurities are each clad with an aluminum alloy intermediate material having a composition containing 0.3 to 2.0% Fe, and the balance Al with inevitable impurities. The surface of each aluminum alloy intermediate material formed on both the surfaces of the aluminum alloy core material is clad with an Al-Si based brazing filler metal, respectively to produce a clad plate. The clad plate is subjected to soaking treatment at 430 to 530°C, and is thereafter subjected to hot rolling. Subsequently, process annealing is performed for at least one time, and cold rolling is performed at a low rolling ratio so that the draft from the final process annealing to the final sheet thickness is >5 to <15% (preferably, >5 to 10%). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing a brazing sheet excellent in strength and wax erosion resistance used for fin materials, tube materials, header tank materials, side support materials, etc. of heat exchangers, and a brazing sheet produced by this method, as well as this The present invention relates to a heat exchanger in which a brazing sheet is brazed.

Generally, heat exchangers are brazed between tubes with side supports, header tanks, a number of tubes made of aluminum alloy spaced parallel to each other between the header tanks, and tubes It consists of corrugated fins. The corrugated fin is formed by processing a fin material into a corrugated shape and brazing the corrugated fin material to a tube material.
The tube, header tank, side support, etc. in the heat exchanger are made of a brazing sheet. As an example of the brazing sheet, a sacrificial anode effect is provided on one or both sides of a core material made of an Al-Mn-Cu alloy. An intermediate material made of an Al—Mn alloy is coated, and both surfaces are made of an Al—Si brazing material (specified in JIS 4343, 4045, for example, an Al-7 to 11 mass% Si alloy) or an Al—Si—Mg brazing material. There is known a brazing sheet in which a brazing material layer made of a material (for example, Al-9 to 13 mass% Si-0.2 to 2 mass% Mg alloy) defined by JIS 4004, 4N04, 4104 is clad. In this brazing sheet, the matrix of the core material has a recrystallized structure, and the matrix of the intermediate material having a sacrificial anode effect has a processed structure. The brazing material layer of the brazing sheet is assembled by contacting the tube, Is inserted into a vacuum or inert gas heating furnace and brazed by heating to a temperature of around 600 ° C, the processed structure of the intermediate material changes into a recrystallized structure during brazing, preventing the occurrence of brazing erosion. It is said that it will be done. (See Patent Document 1).
JP-A-10-298686

  In recent years, automobiles are strongly demanded for comfort and fuel efficiency, and the demand for compactness and high performance of heat exchangers is increasing. Further, from the viewpoint of weight reduction, those members are required to be thinned. For example, the thickness of the tube material is shifting from about 0.3 to 0.4 mm to 0.2 mm. Even when the material is thinned as described above, in order to achieve a level equal to or higher than the durability of the conventional heat exchanger, a very high strength is required as compared with the conventional material.

  However, brazing sheet structure parts such as tubes, header tanks, side supports, etc. in the heat exchanger produced by brazing the conventional brazing sheet material have a recrystallized structure in both the core material and the intermediate material. There is a need for a brazing sheet that is excellent in properties but has insufficient strength and has even greater strength even after brazing.

In view of the above, the present inventors have studied to obtain a heat exchanger in which a brazing sheet with higher strength is produced and brazed to the brazing sheet. as a result,
% By mass (hereinafter,% indicates% by mass), Mn: 0.1 to 2.5%, Zr: 0.05 to 0.3%, Si: 0.1 to 1.2 %, Mg: 0.1-2.0%, Ni: 0.05-1.2%, or 1 type or 2 types, and if necessary, Cu: 0.05-1.0% An aluminum alloy core material having a composition consisting of Al and inevitable impurities, and Fe: 0.3 to 2.0%, and an aluminum alloy intermediate material having a composition consisting of Al and inevitable impurities, A brazing material is prepared, and a laminated material in which these are laminated in the order of brazing material-aluminum alloy intermediate material-aluminum alloy core material-aluminum alloy intermediate material-brazing material, and this laminated material is prepared at a temperature of 430 to 530 ° C. After soaking, it is hot-rolled and then subjected to at least one intermediate annealing. When the cold rolling is performed at a low rolling ratio of more than 5 to less than 15% (preferably more than 5 to 10%) from the final intermediate annealing to the final sheet thickness, the brazing filler metal layer-aluminum alloy intermediate material layer -A rolled brazing sheet formed in the order of aluminum alloy core material layer-aluminum alloy intermediate material layer-brazing material layer is formed, and when this rolled brazing sheet is molded and brazed,
Since the aluminum alloy core material layer having a rolled structure containing Mn: 0.1 to 2.5% and Zr: 0.05 to 0.3% has a characteristic that is difficult to recrystallize, it is recrystallized from the rolled structure during brazing. Unrecrystallized in which 50% or more of crystal grains having a crystal orientation difference of less than 20 ° and a crystal grain size of less than 20 μm are present with respect to adjacent crystal grains in the middle of reaching the recrystallized structure. Change to an organization,
On the other hand, an aluminum alloy intermediate material layer having a rolled structure containing Fe: 0.3 to 2.0% has a characteristic of being easily recrystallized, so that the difference in crystal orientation with respect to adjacent grains from the rolled structure during brazing. Is changed to a recrystallized structure in which 50% or more of crystal grains each having a crystal grain size of 20 μm or more are present at 20 ° or more,
The aluminum alloy core material layer having an unrecrystallized structure is remarkably superior in strength, while the aluminum alloy intermediate material layer having a recrystallized structure is less susceptible to brazing by the brazing material because the erosion path of the molten brazing material is reduced. Research results have been obtained, such as obtaining a heat exchanger having a brazing sheet that exhibits a blocking effect and is therefore excellent in strength and wax erosion resistance.

This invention was made based on the above research results,
(1) Mn: 0.1 to 2.5%, Zr: 0.05 to 0.3%, Si: 0.1 to 1.2%, Mg: 0.1 to 2.0 %, Ni: 0.05 to 1.2% of one or two of them, and the balance of Fe: 0.3 to 2.0 on both surfaces of an aluminum alloy core material composed of Al and inevitable impurities The aluminum alloy intermediate material having a composition containing Al and the remainder consisting of Al and inevitable impurities is stacked, and the Al—Si brazing material is stacked on the aluminum alloy intermediate material formed on both surfaces of the aluminum alloy core material. A laminated material is prepared, and the laminated material is subjected to a soaking treatment at a temperature of 430 to 530 ° C., then hot-rolled, and then subjected to at least one intermediate annealing, and the final thickness from the last intermediate annealing. Up to 5% to less than 15% (preferably more than 5 to Brazing sheet production method of low-rolling ratio is excellent in strength and resistance brazing erodible cold rolling of 0%),
(2) Mn: 0.1 to 2.5%, Zr: 0.05 to 0.3%, Si: 0.1 to 1.2%, Mg: 0.1 to 2.0 %, Ni: 0.05 to 1.2% of one or two of them, and Cu: 0.05 to 1.0%, with the balance being Al and an unavoidable impurity. Aluminum formed on both surfaces of the aluminum alloy core material, with Fe: 0.3-2.0% contained on both surfaces of the alloy core material, the remainder being an aluminum alloy intermediate material composed of Al and inevitable impurities. An Al—Si brazing material is laminated on the alloy intermediate material to prepare a laminated material. The laminated material is soaked at a temperature of 430 to 530 ° C., then hot-rolled, and then at least once. Intermediate annealing is performed and the rolling reduction from the last intermediate annealing to the final sheet thickness exceeds 5 ~ Less than 5% (preferably 5 exceeds 10%) and it has the characteristics of low rolling reduction method of manufacturing a brazing sheet having excellent strength and resistance brazing erodible cold rolling, the.

Since the Zr component in the aluminum alloy has an action of delaying recrystallization during the brazing heat treatment, it is not preferable that Zr is contained in the aluminum alloy intermediate material. Therefore, Zr may be contained as an inevitable impurity. The smaller the content, the better. The content is preferably less than 0.03%. Therefore, the present invention
(3) Mn: 0.1-2.5%, Zr: 0.05-0.3%, Si: 0.1-1.2%, Mg: 0.1-2. 0%, Ni: One or two of 0.05 to 1.2%, further containing Cu: 0.05 to 1.0% as necessary, the remainder being Al and inevitable impurities An aluminum alloy core material having a composition comprising Fe: 0.3 to 2.0% on both sides, and an aluminum alloy intermediate material having a composition consisting of Al and inevitable impurities are stacked, and both surfaces of the aluminum alloy core material are further laminated. Al-Si brazing material is laminated on the aluminum alloy intermediate material formed on each other to produce a laminated material in the order of brazing material-aluminum alloy intermediate material-aluminum alloy core material-aluminum alloy intermediate material-brazing material. The soaking material is soaked at a temperature of 430 to 530 ° C. After performing the above, it is hot-rolled, and then subjected to at least one intermediate annealing, and then cold-rolling at a low rolling ratio of more than 5 to less than 15% from the last intermediate annealing to the final sheet thickness. A method for producing a brazing sheet for a heat exchanger excellent in strength and brazing corrosion resistance, comprising an aluminum alloy having a composition in which the content of Zr contained as an inevitable impurity in the aluminum alloy intermediate material is regulated to less than 0.03% It has the characteristics in the manufacturing method of the aluminum alloy brazing sheet excellent in the intensity | strength and wax corrosion resistance which become.

The heat exchanger produced by using the brazing sheet excellent in strength and wax erosion resistance produced by the production method according to the above (1), (2) or (3), has each crystal orientation with respect to adjacent crystal grains. The difference in crystal orientation between the aluminum alloy core material layer having an unrecrystallized structure in which the difference between the crystal grains is less than 20 ° and each crystal grain size is less than 20 μm is 50% or more and adjacent crystal grains Is composed of an aluminum alloy intermediate material layer having a recrystallized structure in which 50% or more of crystal grains each having a crystal grain size of 20 μm or more and an Al—Si brazing material layer, and a brazing material Layer-aluminum alloy intermediate material layer-aluminum alloy core material layer-aluminum alloy intermediate material layer-brazing material layer To have.
Therefore, the present invention
(4) A brazing sheet excellent in strength and wax erosion resistance produced by the production method described in (1), (2) or (3) above,
(5) A heat exchanger in which the brazing sheet according to (4) is brazed, wherein the brazing sheet constituting the heat exchanger has a difference in crystal orientation between adjacent crystal grains of less than 20 °. And the difference in crystal orientation between the aluminum alloy core material layer having an unrecrystallized structure in which 50% or more of crystal grains each having a crystal grain size of less than 20 μm are present and adjacent crystal grains is 20 ° or more. And an aluminum alloy intermediate material layer having a recrystallized structure in which 50% or more of each crystal grain size is 20 μm or more, and an Al—Si based brazing material layer, and the brazing material layer-aluminum alloy intermediate material The heat exchanger is characterized by being laminated in the order of layer-aluminum alloy core material layer-aluminum alloy intermediate material layer-brazing material layer.

The structure of the brazing sheet excellent in strength and wax erosion resistance brazed to the heat exchanger of the present invention will be described with reference to the drawings. FIG. 1 is an enlarged partial sectional explanatory view of a portion where a fin formed by corrugating a brazing sheet excellent in strength and resistance to brazing corrosion of the present invention is brazed to a normal tube 1 ′. In FIG. 1, 1 'is a normal tube, 2 is a brazing portion, 3 is a fin made of a brazing sheet produced by the method of the present invention, and this fin 3 is composed of a brazing material layer 6-aluminum alloy intermediate material layer 5 An aluminum alloy core material layer 4, an aluminum alloy intermediate material layer 5 ′, a brazing material layer 6 ′, and a brazing sheet clad by being laminated in this order. The brazing portion 2 is formed by brazing the brazing filler metal layer 6 of the fin 3 made of the brazing sheet produced by the method of the present invention to the ordinary tube 1 ′, and the fin 3 is formed on the ordinary tube 1 ′. It is joined.

When the fins produced by the brazing sheet produced by the method of the present invention are brazed, the aluminum alloy core material layer 4 in the fins after brazing has a difference in crystal orientation between adjacent crystal grains of less than 20 ° and Each crystal grain has an unrecrystallized structure in which 50% or more of crystal grains having a grain size of less than 20 μm are present. Since the aluminum alloy core material layer 4 has an extremely fine unrecrystallized structure that has not changed sufficiently from the rolled structure, the strength is excellent due to the influence of dislocation growth, pinning, and the like. However, on the other hand, this non-recrystallized structure has a low resistance to brazing metal erosion. This is because the brazing erosion caused by the molten brazing material during brazing becomes the erosion route of the molten brazing grain boundaries, and there are many grain boundaries (i.e. fine grains). There are a number of erosion pathways, and wax erosion is likely to occur. Therefore, since the unrecrystallized structure has finer crystal grains than the recrystallized structure, significant braze erosion occurs during brazing, which causes buckling and the like.

However, the fin 3 made of the brazing sheet produced by the method of the present invention has a difference in crystal orientation of 20 ° or more with respect to crystal grains adjacent to the aluminum alloy intermediate material layers 5 and 5 ′ by brazing, and A crystal grain having a grain size of 20 μm or more comes to have a recrystallized structure in which 50% or more of the crystal grains exist, and this recrystallized structure is mostly composed of a large crystallized grain size of 20 μm or more. Therefore, even if it is in contact with the brazing filler metal, it has excellent resistance to erosion of the molten brazing filler metal. Therefore, the aluminum alloy intermediate material layers 5 and 5 'serve as a barrier layer against the wax erosion of the aluminum alloy core material layer 4 which is inferior in the wax erosion resistance, and the strength is ensured by the aluminum alloy core material layer having an unrecrystallized structure. Since the aluminum alloy intermediate material layer having a recrystallized structure can secure the brazing erosion resistance, a heat exchanger in which a brazing sheet excellent in strength and brazing erosion resistance is brazed can be obtained.

FIG. 2 is an enlarged partial cross-sectional explanatory view of a portion where a normal fin 3 ′ is brazed to the tube 1 produced from the brazing sheet produced by the method of the present invention. In FIG. 2, reference numeral 1 is the same as that in FIG. 1 except that the tube is made of a brazing sheet made by the method of the present invention, and 3 'is a normal fin, and the description of the reference numerals is omitted. As is apparent from FIG. 2, the tube 1 is laminated in the order of brazing material layer 6-aluminum alloy intermediate material layer 5-aluminum alloy core material layer 4-aluminum alloy intermediate material layer 5'-brazing material layer 6 '. The clad brazing sheet of the present invention is used.
Although not shown, the brazing sheet excellent in strength and wax erosion resistance produced by the method of the present invention can be used for a header tank material, a side support material and the like in a heat exchanger.

  It is possible to obtain a heat exchanger brazed to a brazing sheet having higher strength and better resistance to brazing corrosion, thereby further reducing the thickness of the brazing sheet and further reducing the life of the entire heat exchanger. It can be further improved and brings about an industrially useful effect.

  Next, the reason why the component composition of the brazing sheet produced by the method of the present invention is limited as described above will be described.

A. Component composition Mn of aluminum alloy core material layer:
Mn has the effect of improving the strength of the alloy and has a relatively high solid solubility in the Al alloy, so it has the effect of delaying recrystallization during brazing heat treatment, but its content is less than 0.1% However, since the desired effect cannot be obtained, it is not preferable. On the other hand, if Mn is contained in an amount of more than 2.5%, the crystallized product at the time of casting becomes coarse and the workability deteriorates. Therefore, Mn contained in the core material layer is set to 0.1 to 2.5%. A more preferable range of the Mn content is 1.0 to 1.7%.

Zr:
Zr has the effect of delaying recrystallization during brazing heat treatment. The reason why the amount of Zr added is limited to 0.05 to 0.3% is that the effect is small if it is less than 0.05%, and if it exceeds 0.3%, the crystallized product at the time of casting becomes coarse and workability is reduced. This is because of a decrease. A more preferable range of the Zr content is 0.10 to 0.15%.

Si, Mg, Ni:
These components all have the effect of forming fine precipitates and improving the strength of the alloy, but Si: 0.1 to 1.2%, Mg: 0.1 to 2.0%, Ni: 0 0.05 to 1.2% is limited because Si: less than 0.1%, Mg: less than 0.1%, Ni: less than 0.05%, a desired effect cannot be obtained, If Si exceeds 1.2%, the core material layer may melt at the time of brazing due to a decrease in melting point. If Mg exceeds 2.0%, the self-corrosion resistance of the brazing sheet decreases. Therefore, it is not preferable, and if Ni is contained in excess of 1.2%, the self-corrosion resistance is lowered, which is not preferable. A more preferable range of the Si content in the core layer is 0.5 to 1.0%, a more preferable range of the Mg content is 0.10 to 0.50%, and a more preferable range of the Ni content is 0.3 to 1.0%.

Cu:
Cu has the effect of improving the strength of the alloy and is added as necessary. However, the addition amount is limited to 0.05 to 1.0%, and if it is less than 0.05%, the desired effect is obtained. On the other hand, adding over 1.0% is not preferable because the corrosion resistance of the brazing sheet is lowered and cracks are easily generated during casting. A more preferable range of the Cu content is 0.30 to 0.70%.

B. Component composition of aluminum alloy intermediate layer Fe:
Fe is easy to form coarse intermetallic compounds, and these coarse crystallization products serve as nuclei for recrystallization. Therefore, Fe has an effect of promoting recrystallization during brazing heat treatment. If it is less than 3%, the desired effect cannot be obtained. On the other hand, if it exceeds 2.0%, the self-corrosion resistance of the tube material decreases, which is not preferable. Therefore, the content of Fe is set to 0.3 to 2.0%. A more preferable range of the Fe content is 0.5 to 1.5%.

C. Component composition of brazing material layer The brazing material layer may be an ordinary aluminum alloy brazing material, such as an Al-Si brazing material (for example, Al-7 to 11% by mass Si alloy defined in JIS 4343, 4045) or Al-Si-. Mg-based brazing material (specified in JIS 4004, 4N04, 4104, for example, Al-9 to 13 mass% Si-0.2 to 2 mass% Mg alloy) can be used, and is not particularly limited. .

E. Final cold reduction rate The reason why the reduction rate from the last intermediate annealing to the final sheet thickness is a low pressure reduction rate of more than 5 to less than 15% is that if the reduction rate is 5% or less, the sacrificial material and the aluminum alloy core in the brazing sheet Since both the material and the intermediate material are not recrystallized by brazing and become an unrecrystallized structure, it is not preferable because the role of the intermediate material as a brazing corrosion prevention layer cannot be expected. On the other hand, the reduction ratio is 15% or more. In this case, the sacrificial material, the aluminum alloy core material, and the intermediate material all have a recrystallized structure by brazing, and therefore the role of improving the strength of the core material cannot be expected.

Next, the manufacturing method of the brazing sheet excellent in strength and wax erosion resistance of the present invention will be described.
First, Mn: 0.1 to 2.5%, Zr: 0.05 to 0.3%, Si: 0.1 to 1.2%, Mg: 0.1 to 2.0% Ni: 0.05 to 1.2% of 1 type or 2 types are contained, and Cu: 0.05 to 1.0% is further contained as required, and the remainder consists of Al and inevitable impurities. An aluminum alloy core plate having a composition, Fe: 0.3 to 2.0%, an aluminum alloy intermediate plate having a composition consisting of Al and inevitable impurities, and a brazing plate are prepared. Brazing material plate-aluminum alloy intermediate material plate-aluminum alloy core material plate-aluminum alloy intermediate material plate-brazing material are laminated in this order to produce a laminated material, and this laminated material is soaked at a temperature of 430-530 ° C. After performing this, it is hot-rolled and then subjected to at least one intermediate annealing, It can be produced by cold rolling at a low rolling ratio from intermediate annealing at a reduction ratio to a final thickness of less than 5-15% after.
The brazing sheet thus produced has a structure in which the brazing material layer, the aluminum alloy intermediate material layer, the aluminum alloy core material layer, the aluminum alloy intermediate material layer, and the brazing material layer are clad in this order, and the aluminum alloy core material layer. The aluminum alloy intermediate material layer and the brazing material layer both have a rolled structure. Then, this brazing sheet is formed into fins, tubes, header tanks, side supports, etc., for example, when a fin material is provided between the tubes and placed in a brazing heating furnace and subjected to normal brazing addition heat treatment, brazing The aluminum alloy core layer of the sheet is not completely recrystallized and maintains a high strength as an unrecrystallized structure with excellent strength, while the aluminum alloy intermediate layer completely recrystallizes and is resistant to wax erosion ( It has excellent properties for suppressing wax erosion to the core material layer.

All have dimensions of 20 mm in length, 52 mm in width, and 125 mm in length, and become an aluminum alloy ingot and an aluminum alloy intermediate material layer to be an aluminum alloy core material layer having a chemical composition shown in Tables 1 to 3. Aluminum alloy ingot, and Si: 7.5% by mass, and the aluminum alloy ingot to be a brazing material with the balance consisting of Al and inevitable impurities are chamfered by 1/4 inch on each side, and the temperature: Homogenization was performed at 530 ° C for 4 hours.

The aluminum alloy ingot of the aluminum alloy core material layer, the aluminum alloy ingot of the aluminum alloy intermediate material layer, and the aluminum alloy ingot of the brazing material which have been subjected to the homogenization treatment are subjected to a temperature: 480 ° C. for 1 hour. After soaking, aluminum alloy ingot of brazing material-aluminum alloy ingot of aluminum alloy intermediate layer-aluminum alloy ingot of aluminum alloy core layer-aluminum alloy ingot of aluminum alloy intermediate material layer-aluminum of brazing material A laminated material was produced by superposing the alloy ingots in this order, and the laminated material was hot-rolled to obtain a clad material having a thickness of about 6 mm. The clad material is further rolled to a thickness of about 1.3 mm by cold rolling, and then subjected to salt bath annealing at 500 ° C. as the first intermediate annealing, and further cold rolled to obtain a thickness of 0.212 to A clad rolled material within a range of 0.232 mm is prepared, and the obtained clad rolled material is subjected to batch annealing under the condition of holding the second intermediate annealing at a temperature of 360 ° C. for 3 hours, and further shown in Tables 1 and 2 The final rolling at the specified reduction rate results in a cladding ratio of 10% brazing material layer (20% on both sides), 10% intermediate layer (20% on both sides), and 60% core layer. Plate thickness: Rolled brazing sheet materials A to e having a thickness of 0.2 mm were prepared.

Further, the composition of Mn: 1.2%, Cu: 0.4%, Si: 0.2%, Fe: 0.3% shown in the above-mentioned Patent Document 1, with the balance being Al and inevitable impurities And a composition comprising Si: 0.2%, Fe: 0.3%, Mn: 0.2% on one side of the core layer having a recrystallized structure, the balance being Al and inevitable impurities. A brazing material layer-core material layer-intermediate layer-brazing material layer formed by laminating an intermediate material layer having a processed structure and forming a brazing material layer defined in JIS 4104 outside the core material layer and the intermediate layer. A rolled brazing sheet material f having a laminated structure was prepared.

Examples 1 to 22, Comparative Examples 1 to 9 and Conventional Example The brazing material layers of the rolled brazing sheet materials A to f having the configurations shown in Tables 1 and 2 were fixed so as to contact the fin material, and the nitrogen atmosphere was maintained. A heat exchanger having a brazing sheet was prepared by charging in a heating furnace and holding at a temperature of 600 ° C. for 3 minutes to produce a heat exchanger having a brazing sheet (the brazing sheet material after brazing the rolled brazing sheet material to the fins) This is the same as the brazing sheet. About this brazing sheet, the crystal grain orientation and grains in one field of view of 1.6 mm × 1.6 mm at any part of the cross section of the aluminum alloy core material layer and the aluminum alloy intermediate material layer formed on both surfaces of the aluminum alloy core material layer The diameter is measured by SEM-EBSP (EBSP: Electron Back-Scatter Diffraction Pattern). Based on the measurement results, the difference in crystal orientation between adjacent crystal grains is less than 20 °, and each crystal grain size is A structure in which 50% or more of crystal grains less than 20 μm are present is regarded as an unrecrystallized structure, and the difference in crystal orientation between adjacent crystal grains is 20 ° or more, and crystal grains each having a crystal grain size of 20 μm or more are 50 % Or more of the structure was recognized as a recrystallized structure, and the results are shown in Tables 3 to 4 as the results obtained from Examples 1 to 22, Comparative Examples 1 to 9 and the conventional examples. . Further, the following tests were conducted.

A tensile test piece was prepared from a brazing sheet brazed with a tensile test fin, and a tensile test was performed using this tensile test piece. The results are shown as results of Examples 1 to 22, Comparative Examples 1 to 9, and the conventional example. Shown in 3-4.

Aluminum alloy intermediate material formed on both surfaces of the aluminum alloy core material layer by observing cross sections after brazing of the aluminum alloy intermediate material layer formed on both surfaces of the aluminum alloy core material layer in the brazing sheet for brazing corrosion resistance test The maximum brazing erosion depth from the surface of the layer was measured and the results were brazed to the heat exchanger by showing in Tables 3-4 as results of Examples 1-22, Comparative Examples 1-9 and Conventional Examples The brazing sheet was evaluated for its resistance to wax erosion.

In Table 2, the values marked with * indicate that the values deviate from the conditions of the present invention.

  From the results shown in Tables 1 to 4, when the measurement results obtained in Examples 1 to 22 and the measurement results obtained in the conventional examples are compared, the rolled brazing sheet materials A to V obtained in Examples 1 to 22 are used. Compared with the rolled brazing sheet material f obtained in the conventional example, the strength after brazing and the resistance to brazing erosion are superior, so the rolled brazing sheet materials A to V obtained by the production method of the present invention are used. The heat exchangers 1 to 22 of the present invention obtained by brazing have higher strength and braze erosion resistance than the heat exchanger obtained by brazing the rolled brazing sheet material f obtained by the conventional manufacturing method. It turns out that it is excellent. However, as seen in Comparative Examples 1 to 9, the comparative heat exchangers 1 to 9 formed by brazing the rolled brazing sheet materials W to e which deviate from the conditions of the present invention have strength and wax erosion resistance. It turns out that at least one of is inferior since it is inferior.

It is a fragmentary sectional view for demonstrating the structure | tissue of the fin material of the junction part vicinity which brazed the fin which consists of a brazing sheet manufactured with the method of this invention to the normal tube. It is a fragmentary sectional view for demonstrating the structure | tissue of the tube material of the junction part vicinity which brazed the tube which consists of a brazing sheet manufactured with the method of this invention to the normal fin.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tube 1 'Normal tube 2 Brazing part 3 Fin 3' Normal fin 4 Aluminum alloy core material layer 5 Aluminum alloy intermediate material layer 5 'Aluminum alloy intermediate material layer 6 Aluminum alloy brazing material layer 6' Aluminum alloy brazing material layer

Claims (5)

% By mass (hereinafter,% indicates% by mass), Mn: 0.1 to 2.5%, Zr: 0.05 to 0.3%, Si: 0.1 to 1.2 %, Mg: 0.1-2.0%, Ni: 0.05-1.2% of one or two kinds of aluminum alloy core material of the composition consisting of Al and inevitable impurities An aluminum alloy intermediate material containing Fe: 0.3 to 2.0% on both sides and the balance of Al and unavoidable impurities being stacked, and an aluminum alloy intermediate material formed on both surfaces of the aluminum alloy core material. An Al—Si brazing material is laminated on each other to produce a laminated material. The laminated material is soaked at a temperature of 430 to 530 ° C., then hot-rolled, and then subjected to at least one intermediate annealing. The rolling reduction from the last intermediate annealing to the final sheet thickness exceeds 5 ~ 1 Brazing sheet manufacturing method of a highly strong and resistant brazing erodible, characterized in that cold rolling at a low rolling ratio of less than%. % By mass (hereinafter,% indicates% by mass), Mn: 0.1 to 2.5%, Zr: 0.05 to 0.3%, Si: 0.1 to 1.2 %, Mg: 0.1-2.0%, Ni: 0.05-1.2% of 1 type or 2 types, further containing Cu: 0.05-1.0%, Fe: 0.3-2.0% Fe on both sides of an aluminum alloy core material composed of the remaining Al and unavoidable impurities, and an aluminum alloy intermediate material composed of the remaining Al and unavoidable impurities. An aluminum alloy intermediate material formed on both surfaces of the aluminum alloy core material is laminated with an Al-Si brazing material to prepare a laminated material, and this laminated material is subjected to a soaking treatment at a temperature of 430 to 530 ° C. This is hot-rolled and then subjected to at least one intermediate annealing, and from the last intermediate annealing Brazing sheet manufacturing method of high strength and resistance brazing erodible characterized by cold rolling at a reduction ratio at a low rolling ratio of less than 5 over 15% to a final thickness. The said aluminum alloy intermediate material consists of an aluminum alloy of the composition which controlled content of Zr contained as an unavoidable impurity to less than 0.03%, The intensity | strength and brazing-proof corrosion resistance of Claim 1 or 2 characterized by the above-mentioned. An excellent brazing sheet manufacturing method. A brazing sheet excellent in strength and wax erosion resistance, characterized by being produced by the production method according to claim 1, 2 or 3. A heat exchanger formed by brazing the brazing sheet according to claim 4, wherein the brazing sheet constituting the heat exchanger has a difference in crystal orientation of adjacent crystal grains of less than 20 ° and each The crystal orientation of each of the aluminum alloy core material layer having an unrecrystallized structure in which 50% or more of crystal grains having a crystal grain size of less than 20 μm are present and adjacent crystal grains formed on both surfaces of the aluminum alloy core material layer Are formed on the aluminum alloy intermediate material layer having a recrystallized structure in which the crystal grain size is 20 ° or more and each crystal grain size is 20 μm or more and 50% or more of the crystal grains, and the aluminum alloy intermediate material layer. A heat exchanger comprising an Al—Si brazing material layer.

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