JP6063644B2 - Method for producing brazing aluminum material - Google Patents

Description

  The present invention relates to a method for producing a brazing aluminum material used for producing a brazed product, and a method for producing a brazed product using the brazing aluminum material.

  In the present specification and claims, the term “aluminum” is used to include aluminum and its alloys. In the present specification and claims, the notation “Al” means a single Al metal.

  When mass producing heat exchangers for automobiles, etc., there is vacuum brazing as a brazing method that does not use flux, but in addition to this, an Al—Si alloy brazing material layer to which trace amounts of Mg and Bi are added is used. An aluminum brazing sheet prepared by etching with sodium hydroxide aqueous solution or nitric acid aqueous solution is used to make a temporary assembly, and this temporary assembly is brazed by heating in an inert atmosphere brazing furnace. There is a method of joining to obtain a brazed product (see Patent Documents 1 and 2).

JP-A-7-164138 JP-A-7-185797

  However, when a sodium hydroxide aqueous solution or a nitric acid aqueous solution is used as the etching treatment liquid in this way, the step of washing such as washing the brazing material to which the treatment liquid adheres after the etching treatment, and further washing with pure water is performed. Since it is necessary (paragraph 0012 of Patent Document 1 and Paragraph 0012 of Patent Document 2), there is a problem that the production efficiency of the brazing aluminum material is low.

  The present invention has been made in view of such a technical background, and does not require (can be omitted) cleaning of the aluminum material after the etching treatment with water. And it aims at providing the manufacturing method of a brazing article.

  In order to achieve the above object, the present invention provides the following means.

[1] including an etching treatment step of treating an aluminum material with a monocarboxylic acid aqueous solution,
A method for producing an aluminum material for brazing, wherein the monocarboxylic acid aqueous solution is a monocarboxylic acid aqueous solution set at a temperature of 70 ° C. or higher and lower than the boiling point of the monocarboxylic acid aqueous solution.

  [2] As the monocarboxylic acid aqueous solution, a formic acid aqueous solution having a formic acid content of 10% by mass to 70% by mass and having a temperature lower than the boiling point of the formic acid aqueous solution at 70 ° C. or higher is used. The method for producing a brazing aluminum material according to item 1 above.

  [3] As the monocarboxylic acid aqueous solution, an acetic acid aqueous solution having an acetic acid content of 10% by mass to 50% by mass and having a temperature lower than the boiling point of the acetic acid aqueous solution at 80 ° C. or higher is used. The method for producing a brazing aluminum material according to item 1 above.

  [4] Any one of 1 to 3 above, further comprising a drying step of drying the aluminum material that has undergone the etching treatment step by heating to a temperature not lower than the boiling point of the monocarboxylic acid aqueous solution. The manufacturing method of the aluminum material for brazing as described in a term.

  [5] The method for producing an aluminum material for brazing as described in any one of [1] to [4], wherein the aluminum material is not provided with a water washing step for washing with water.

  [6] The aluminum material for brazing according to any one of items 1 to 5, wherein a brazing sheet in which an Al—Si alloy brazing material is clad on at least a part of the surface of the aluminum material is used as the aluminum material. Manufacturing method.

  [7] An aluminum material for brazing obtained by the production method according to any one of items 1 to 6.

  [8] After assembling a plurality of brazing aluminum materials obtained by the manufacturing method according to any one of items 1 to 6, brazing and joining are performed by heating in an inert atmosphere. A method for producing a brazing product, comprising obtaining a brazing product.

  In the invention of [1], since the monocarboxylic acid aqueous solution in a specific temperature range is used as the treatment liquid, the aluminum material can be etched, and since the monocarboxylic acid aqueous solution is used as the treatment liquid, the washing operation of the aluminum material after the etching treatment with water Is not required (can be omitted). Therefore, the brazing aluminum material can be manufactured with high production efficiency.

  In the invention of [2], the aluminum material is treated with a formic acid aqueous solution having a formic acid content of 10% by mass to 70% by mass and set to a temperature lower than the boiling point of the formic acid aqueous solution at 70 ° C. or higher. Etching efficiency can be further improved.

  In the invention of [3], the aluminum material is treated with an acetic acid aqueous solution having an acetic acid content of 10% by mass to 50% by mass and set to a temperature lower than the boiling point of the acetic acid aqueous solution at 80 ° C. or higher. Etching efficiency can be further improved.

  The invention of [4] further includes a drying step in which the aluminum material that has undergone the etching treatment step is dried by heating to a temperature not lower than the boiling point of the monocarboxylic acid aqueous solution. Evaporation and removal of the attached monocarboxylic acid can be efficiently performed, and the production efficiency of the brazing aluminum material can be further improved.

  In the invention of [5], since the water washing process for washing the aluminum material is not provided, the brazing aluminum material can be produced with high production efficiency.

  In the invention of [6], an aluminum material for brazing (brazing sheet) excellent in brazeability can be produced.

  In the invention of [7], an aluminum material for brazing having good brazing properties is provided.

  In the invention of [8], it is possible to produce an aluminum brazed product that is well brazed and joined with high production efficiency.

It is sectional drawing which shows an example of the assembly goods (temporary assembly) before brazing. It is sectional drawing which shows one Embodiment of the brazing article obtained with the manufacturing method of this invention.

  The method for producing an aluminum material for brazing according to the present invention includes an etching treatment step of treating an aluminum material with a monocarboxylic acid aqueous solution, and the monocarboxylic acid aqueous solution has a boiling point of 70 ° C. or higher and the monocarboxylic acid aqueous solution. A monocarboxylic acid aqueous solution set at a lower temperature is used.

  In this manufacturing method, since the monocarboxylic acid aqueous solution in a specific temperature range (temperature higher than 70 ° C. and lower than the boiling point of the monocarboxylic acid aqueous solution) is used as the pretreatment liquid, the aluminum material can be etched well. In addition, since the monocarboxylic acid aqueous solution is used as the treatment liquid, it is not necessary to wash the aluminum material after the etching treatment with water (can be omitted), and therefore it is possible to produce the brazing aluminum material with high production efficiency. it can.

The aluminum material is not particularly limited.
-A3003 aluminum material-Brazing sheet (brazing sheet in which a brazing material layer such as an Al-Si alloy is pressed on at least one surface of an aluminum plate)
Etc.

  The monocarboxylic acid content in the monocarboxylic acid aqueous solution is not particularly limited, but is preferably set to 10% by mass to 70% by mass. By setting to 10 mass%-70 mass%, etching processing efficiency can be improved.

  The monocarboxylic acid is not particularly limited, and examples thereof include formic acid and acetic acid. Among these, it is preferable to use formic acid. In this case, the etching processing efficiency can be further improved.

  When the formic acid aqueous solution is used as the monocarboxylic acid aqueous solution, the formic acid content in the formic acid aqueous solution is preferably set to 10% by mass to 70% by mass. Among these, it is particularly preferable to use a formic acid aqueous solution having a formic acid content of 30% by mass to 60% by mass.

  When an acetic acid aqueous solution is used as the monocarboxylic acid aqueous solution, the acetic acid content in the acetic acid aqueous solution is preferably set to 10% by mass to 50% by mass. Among them, it is particularly preferable to use an acetic acid aqueous solution having an acetic acid content of 20% by mass to 40% by mass.

  The temperature of the monocarboxylic acid aqueous solution used for the etching treatment is set to 70 ° C. or higher and lower than the boiling point of the monocarboxylic acid aqueous solution. Etching performance can be sufficiently exhibited when the temperature is 70 ° C. or higher, and etching treatment can be efficiently performed when the temperature is lower than the boiling point of the monocarboxylic acid aqueous solution.

  When a formic acid aqueous solution is used as the monocarboxylic acid aqueous solution, the temperature of the formic acid aqueous solution is preferably set to 70 ° C. or higher and lower than the boiling point of the formic acid aqueous solution. In particular, the temperature of the formic acid aqueous solution is more preferably set to a temperature of 90 ° C. or higher and lower than the boiling point of the formic acid aqueous solution.

  When an aqueous acetic acid solution is used as the monocarboxylic acid aqueous solution, the temperature of the aqueous acetic acid solution is preferably set to a temperature of 80 ° C. or higher and lower than the boiling point of the aqueous acetic acid solution.

  In the etching process, the treatment method for treating the aluminum material with the monocarboxylic acid aqueous solution is not particularly limited. For example, the aluminum material is immersed in the monocarboxylic acid aqueous solution, and the aluminum material is Examples thereof include a method of continuously spraying a carboxylic acid aqueous solution.

  In the production method of the present invention (a method for producing a brazing aluminum material), a drying step may be provided after the etching treatment step. That is, the aluminum material that has been subjected to the etching treatment step may be dried by heating to a temperature that is equal to or higher than the boiling point of the carboxylic acid aqueous solution to obtain a brazing aluminum material.

  In the drying step, the drying method is not particularly limited. For example, air blowing (blowing air having a temperature equal to or higher than the boiling point of the aqueous carboxylic acid solution used in the etching process) or a heating and drying furnace is performed. And then drying.

  Thus, after assembling a plurality of aluminum materials that have been subjected to the drying step, brazing and joining are performed by heating in an inert atmosphere to obtain a brazed product 1.

  Alternatively, the brazed product 1 can be manufactured without providing the drying step. In this case, the drying step is omitted, and the aluminum material that has been subjected to the etching treatment step is placed in a brazing furnace (inert atmosphere) at a predetermined temperature as it is and brazed to perform brazing 1 Get. The monocarboxylic acid adhering to the aluminum material is immediately evaporated and removed by the high temperature in the furnace when it is put in the brazing furnace, and then the brazing joining proceeds.

  The temperature in the brazing furnace is preferably set to 590 ° C to 620 ° C.

  The inert atmosphere is not particularly limited, and examples thereof include a nitrogen atmosphere.

  Next, specific examples of the present invention will be described, but the present invention is not particularly limited to these examples.

<Example 1>
As shown in FIG. 1, a brazing sheet 3 having a thickness of 1.6 mm (an A4045Al—Si alloy brazing material layer 12 having a thickness of 0.2 mm) is applied to an A3003 aluminum plate (horizontal plate) 2 having a thickness of 1.6 mm. An A3003 aluminum plate 11 having a thickness of 1.2 mm / A4045Al-Si alloy brazing material layer 12 having a thickness of 0.2 mm was vertically assembled to obtain an assembly (temporary assembly) 30 of a reverse T joint.

  The temporary assembly 30 was etched by immersion for 5 minutes in a formic acid-based treatment liquid (formic acid aqueous solution having a formic acid content of 20 mass%, boiling point 100 ° C.) at 75 ° C. Next, the temporary assembly 30 is subjected to a drying process by air blowing (air blowing at 150 ° C.), and then the temporary assembly (aluminum material for brazing) 30 is subjected to a brazing furnace (nitrogen atmosphere, (Dew point: -70 ° C., oxygen concentration: 5 ppm) was heated for 5 minutes and brazed to obtain a brazed product 1 shown in FIG. In FIG. 2, 20 is a fillet.

<Example 2>
A brazed product 1 was obtained in the same manner as in Example 1 except that a formic acid aqueous solution (boiling point 100 ° C.) having a formic acid content of 40% by mass was used as the formic acid-based treatment liquid.

<Example 3>
A brazed article 1 was obtained in the same manner as in Example 1 except that a formic acid aqueous solution (boiling point 101 ° C.) having a formic acid content of 60% by mass was used as the formic acid-based treatment liquid.

<Example 4>
A brazed product 1 was obtained in the same manner as in Example 1 except that a formic acid aqueous solution having a temperature of 95 ° C. was used as the formic acid-based treatment liquid.

<Example 5>
A brazed article 1 was obtained in the same manner as in Example 1 except that a formic acid aqueous solution having a formic acid content of 40% by mass and a temperature of 95 ° C. was used as the formic acid-based treatment liquid.

<Example 6>
A brazed article 1 was obtained in the same manner as in Example 1 except that a formic acid aqueous solution having a formic acid content of 60% by mass and a temperature of 95 ° C. was used as the formic acid-based treatment liquid.

<Comparative Example 1>
A brazed article 1 was obtained in the same manner as in Example 1 except that a formic acid aqueous solution having a formic acid content of 5% by mass and a temperature of 50 ° C. was used as the formic acid-based treatment liquid.

<Comparative example 2>
A brazed product 1 was obtained in the same manner as in Example 1 except that a formic acid aqueous solution having a temperature of 50 ° C. was used as the formic acid-based treatment liquid.

<Comparative Example 3>
A brazed article 1 was obtained in the same manner as in Example 1 except that a formic acid aqueous solution having a formic acid content of 40% by mass and a temperature of 50 ° C. was used as the formic acid-based treatment liquid.

<Comparative example 4>
A brazed article 1 was obtained in the same manner as in Example 1 except that a formic acid aqueous solution having a formic acid content of 60% by mass and a temperature of 50 ° C. was used as the formic acid-based treatment liquid.

<Comparative Example 5>
A brazed product 1 was obtained in the same manner as in Example 1 except that a formic acid solution having a formic acid content of 100% by mass and a temperature of 50 ° C. was used as the formic acid-based treatment solution.

<Comparative Example 6>
A brazed article 1 was obtained in the same manner as in Example 1 except that a formic acid aqueous solution (boiling point 100 ° C.) having a formic acid content of 5 mass% was used as the formic acid-based treatment liquid.

<Comparative Example 7>
A brazed article 1 was obtained in the same manner as in Example 1 except that a formic acid solution having a formic acid content of 100% by mass (boiling point: 101 ° C.) was used as the formic acid-based treatment solution.

<Comparative Example 8>
A brazed article 1 was obtained in the same manner as in Example 1 except that a formic acid aqueous solution having a formic acid content of 5% by mass and a temperature of 95 ° C. was used as the formic acid-based treatment liquid.

<Comparative Example 9>
A brazed article 1 was obtained in the same manner as in Example 1 except that a formic acid solution having a formic acid content of 100% by mass and a temperature of 95 ° C. was used as the formic acid treatment solution.

<Example 7>
Brazed article in the same manner as in Example 1 except that instead of the formic acid-based treatment liquid, an acetic acid-based treatment liquid (acetic acid content of 20% by mass, acetic acid aqueous solution having a temperature of 95 ° C., boiling point: 104 ° C.) 1 was obtained.

<Example 8>
A brazed product 1 was obtained in the same manner as in Example 7, except that an acetic acid aqueous solution (boiling point 107 ° C.) having an acetic acid content of 40% by mass was used as the acetic acid-based treatment liquid.

<Comparative Example 10>
A brazed article 1 was obtained in the same manner as in Example 7 except that an acetic acid content was 5% by mass and an acetic acid aqueous solution having a temperature of 50 ° C. was used as the acetic acid-based treatment liquid.

<Comparative Example 11>
A brazed article 1 was obtained in the same manner as in Example 7 except that an acetic acid aqueous solution having a temperature of 50 ° C. was used as the acetic acid-based treatment liquid.

<Comparative Example 12>
A brazed product 1 was obtained in the same manner as in Example 7 except that an acetic acid content was 40% by mass and an acetic acid aqueous solution having a temperature of 50 ° C. was used as the acetic acid-based treatment liquid.

<Comparative Example 13>
A brazed article 1 was obtained in the same manner as in Example 7 except that an acetic acid content was 60% by mass and an acetic acid aqueous solution having a temperature of 50 ° C. was used as the acetic acid-based treatment liquid.

<Comparative example 14>
A brazed product 1 was obtained in the same manner as in Example 7 except that an acetic acid solution having an acetic acid content of 100% by mass and a temperature of 50 ° C. was used as the acetic acid processing solution.

<Comparative Example 15>
A brazed article 1 was obtained in the same manner as in Example 7 except that an acetic acid content was 5% by mass and an acetic acid aqueous solution having a temperature of 75 ° C. was used as the acetic acid-based treatment liquid.

<Comparative Example 16>
A brazed article 1 was obtained in the same manner as in Example 7 except that an acetic acid aqueous solution having a temperature of 75 ° C. was used as the acetic acid-based treatment liquid.

<Comparative Example 17>
A brazed article 1 was obtained in the same manner as in Example 7 except that an acetic acid content was 40% by mass and an acetic acid aqueous solution having a temperature of 75 ° C. was used as the acetic acid-based treatment liquid.

<Comparative Example 18>
A brazed product 1 was obtained in the same manner as in Example 7 except that an acetic acid content was 60% by mass and an acetic acid aqueous solution having a temperature of 75 ° C. was used as the acetic acid-based treatment liquid.

<Comparative Example 19>
A brazed article 1 was obtained in the same manner as in Example 7 except that an acetic acid solution having an acetic acid content of 100% by mass and a temperature of 75 ° C. was used as the acetic acid treatment liquid.

<Comparative Example 20>
A brazed product 1 was obtained in the same manner as in Example 7, except that an acetic acid aqueous solution (boiling point: 101 ° C.) having an acetic acid content of 5 mass% was used as the acetic acid-based treatment liquid.

<Comparative Example 21>
A brazed product 1 was obtained in the same manner as in Example 7 except that an acetic acid aqueous solution (boiling point 111 ° C.) having an acetic acid content of 60% by mass was used as the acetic acid-based treatment liquid.

<Comparative Example 22>
A brazed product 1 was obtained in the same manner as in Example 7 except that an acetic acid solution (boiling point 118 ° C.) having an acetic acid content of 100% by mass was used as the acetic acid-based treatment solution.

<Reference Example 1>
A temporary assembly 30 (see FIG. 1) similar to that in Example 1 was immersed in a nitric acid-based treatment solution (a nitric acid aqueous solution having a nitric acid content of 34% by mass) at 50 ° C. for 5 minutes, and then removed. After washing with pure water 5 times and then drying the temporary assembly 30 in a heating furnace at 150 ° C., the temporary assembly 30 is brazed at 600 ° C. (nitrogen atmosphere, dew point) : -70 ° C., oxygen concentration: 5 ppm) and heated for 5 minutes to carry out brazing and joining to obtain a brazed product.

<Reference Example 2>
A brazed product was obtained in the same manner as in Reference Example 1 except that an aqueous nitric acid solution having a nitric acid content of 68% by mass was used as the nitric acid-based treatment liquid.

<Reference Example 3>
A brazed product was obtained in the same manner as in Reference Example 1 except that a nitric acid aqueous solution having a temperature of 75 ° C. was used as the nitric acid-based treatment liquid.

<Reference Example 4>
A brazed product was obtained in the same manner as in Reference Example 1 except that an aqueous nitric acid solution having a nitric acid content of 68% by mass and a temperature of 75 ° C. was used as the nitric acid-based treatment liquid.

  The brazeability of each brazed product obtained as described above was evaluated based on the following evaluation method. These evaluation results are shown in Tables 1-3.

<Brassability evaluation method>
Appearance observation and cross-sectional observation of the brazed product were performed and evaluated based on the following criteria.
(Criteria)
“◯”: Uniform fillet is formed and brazing is good “△”… Wax is wet on the base material (horizontal plate) but fillet is non-uniform “×”… Base material ( The horizontal plate is not wet and no fillets are formed.

  As is apparent from the table, the brazing products of Examples 1 to 8 manufactured using the brazing aluminum material obtained by the manufacturing method of the present invention had good brazing properties.

  On the other hand, the brazing products of Comparative Examples 1 to 22 manufactured without adopting the manufacturing method of the present invention had poor brazing properties.

  In addition, about Example 1-8, it replaced with air blow (blowing of 150 degreeC air) as a drying method, respectively, when the method of putting in a 150 degreeC drying furnace for 5 minutes and drying was employ | adopted, the obtained brazing The evaluation of the brazing property of each product was “◯” (good brazing property).

  Moreover, about Examples 1-8, after cutting a droplet, air blow (blowing of air of 150 degreeC) is not performed (a drying process is abbreviate | omitted), and a temporary assembly is directly brazed to 600 degreeC ( When brazing and joining were carried out by placing in a nitrogen atmosphere, dew point: -70 ° C, oxygen concentration: 5 ppm for 5 minutes and brazing, the evaluations of the brazing properties of the obtained brazed products were all “O” (brazing) It was good on attachment).

  The aluminum material manufactured by the method for manufacturing a brazing aluminum material according to the present invention is used for aluminum brazing products such as automotive heat exchangers and various industrial heat exchangers. The application is not limited.

  In addition, the use of the brazed product manufactured by the method for manufacturing a brazed product according to the present invention is not particularly limited, and examples thereof include automotive heat exchangers and various industrial heat exchangers. .

DESCRIPTION OF SYMBOLS 1 ... Brazing article 2 ... Board 3 ... Brazing sheet 11 ... Base layer 12 ... Brazing material layer 30 ... Assembly | attachment (temporary assembly)

Claims (5)

An etching process for treating the aluminum material with a monocarboxylic acid aqueous solution ;
A drying step in which the aluminum material that has undergone the etching treatment step is dried by heating to a temperature equal to or higher than the boiling point of the monocarboxylic acid aqueous solution,
In the etching treatment step, as the monocarboxylic acid aqueous solution, a monocarboxylic acid aqueous solution set at a temperature lower than the boiling point of the monocarboxylic acid aqueous solution at 70 ° C. or higher is used. Production method. In the etching treatment step, as the monocarboxylic acid aqueous solution, a formic acid aqueous solution having a formic acid content of 10% by mass to 70% by mass and having a temperature lower than the boiling point of the formic acid aqueous solution at 70 ° C. or higher is used. The manufacturing method of the aluminum material for brazing of Claim 1 characterized by the above-mentioned. In the etching treatment step, as the monocarboxylic acid aqueous solution, an acetic acid aqueous solution having an acetic acid content of 10% by mass to 50% by mass and having a temperature lower than the boiling point of the acetic acid aqueous solution at 80 ° C. or higher is used. The manufacturing method of the aluminum material for brazing of Claim 1 characterized by the above-mentioned. The method for producing an aluminum material for brazing according to any one of claims 1 to 3 , wherein a water washing step of washing the aluminum material with water is not provided. The brazing aluminum material according to any one of claims 1 to 4, wherein a brazing sheet in which an Al-Si alloy brazing material is clad on at least a part of the surface of the aluminum material is used as the aluminum material. Method.

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