JP5622349B2 - Aluminum alloy material and aluminum alloy brazing sheet - Google Patents

Description

  The present invention relates to an aluminum alloy material and an aluminum alloy brazing sheet used as a core material of a brazing sheet used for a heat exchanger for automobiles and the like.

  Heat exchangers such as condensers, evaporators, and intercoolers mounted on automobiles are combined by alternately stacking tube materials, press-formed plate materials, and corrugated fin materials that are roll-formed into shapes having fluid passages. It is manufactured by brazing in the state where it was done. The plate material formed into these tube material, plate material, and fin material is made of an aluminum alloy brazing sheet or an aluminum alloy brazing sheet in which an aluminum alloy is used as a core material and a brazing material is laminated thereon.

Al-Mn-based alloys have been the mainstream of conventional brazing aluminum alloy plates and core materials for aluminum alloy brazing sheets. And in order to improve the intensity | strength of such an aluminum alloy, the brazing sheet | seat which made the core material the Al-Mn type alloy which added 0.1-1.0 mass% Cu and Si, Fe, and Mg (patent document 1). Patent Document 2) has been proposed. In order to further improve the strength, a brazing sheet having an addition amount of Cu exceeding 0.7% by mass and not more than 2.5% by mass and using an Al—Mn alloy added with Si and Fe as a core (Patent Document 3) ) Has been proposed.
JP-A-4-202735 (second page, upper right column, line 12 to same page, lower left column, line 17) JP-A-5-339666 (paragraphs 0005 to 0013) JP-A-8-291353 (paragraphs 0010 to 0015, paragraph 0025)

  The operating temperature of the heat exchanger manufactured from the prior art aluminum alloy brazing sheet is approximately 100 ° C. or less. However, in recent years, heat exchangers are required to be smaller and have higher performance, and heat exchangers are used at higher pressures and higher temperatures, so brazing aluminum alloy plates and aluminum alloy brazing sheets, As for the aluminum alloy material used as the core material, it is required to increase the strength of the aluminum alloy material at a high temperature of 150 ° C. or higher. Under such high temperature aging, the aluminum alloy brazing sheets of Patent Documents 1 and 2 are insufficient in strength and have limited use. On the other hand, as disclosed in Patent Document 3, an aluminum alloy material containing a large amount of Cu may have a reduced corrosion resistance. In addition, heat exchangers are also required to be lighter, and as a result, aluminum alloy plates for brazing and aluminum alloy brazing sheets are being made thinner, and as a result, further improvements in strength and high corrosion resistance are required. ing.

  The present invention has been made in view of the above problems, and an object thereof is to provide an aluminum alloy brazing sheet excellent in high-temperature strength over time and corrosion resistance, and an aluminum alloy material as a core material thereof.

In order to solve the above-mentioned problems, an aluminum alloy material according to the present invention is provided with a brazing material on at least one side, brazed at 595 ° C. for 2 minutes and then held at 180 ° C. for 300 hours, and then tensile strength at 180 ° C. Is an aluminum alloy material used as a core material of an aluminum alloy brazing sheet having a viscosity of 145 MPa or more, containing Cu: more than 1.5% by mass and not more than 2.5% by mass, and Fe: 0.05-1 0.5 % by mass, Mg: 0.05-0.6% by mass, Ni: 0.05-1.5% by mass , Cr: 0.05-0.3% by mass, Ti: 0.05-0.3 % By mass, Zr: 0.05 to 0.3% by mass, V: 0.05 to 0.3% by mass, Sn: 0.01 to 0.1% by mass, Cd: 0.01 to 0.1% by mass , In: one selected from 0.01 to 0.1% by mass; Contains not less than 1.87% by mass in total, and the balance consists of Al and inevitable impurities, and the inevitable impurities are Si: less than 0.2% by mass and Mn: less than 0.06% by mass. It is regulated.

In this way, by limiting the Cu concentration to a range higher than that of the prior art, an effect of improving the strength of the aluminum alloy by solid solution and precipitation strengthening of Cu can be obtained, and further, the decrease in strength of the aluminum alloy material over time can be reduced. And the corrosion resistance can be improved. Further, by limiting the concentration of Si and Mn, it is possible to prevent a decrease in corrosion resistance due to the addition of a large amount of Cu and maintain high corrosion resistance .

Moreover , the strength of the aluminum alloy material can be further improved by adding a prescribed amount of Fe, Mg, Ni, Cr, Ti, Zr , V, Sn, Cd, and In .

The aluminum alloy brazing sheet according to the present invention is characterized in that the aluminum alloy material according to the present invention is used as a core, and a brazing material made of an aluminum alloy is provided on one or both sides thereof.

  Thus, brazing joining with the board | plate material which is not provided with the brazing material becomes easy by providing the brazing material on the single side | surface or both surfaces.

Alternatively, an aluminum alloy brazing sheet according to the present invention, the sacrificial an aluminum alloy material according to the present invention as a core, comprising a brazing material made of an aluminum alloy on one surface thereof, made of aluminum or an aluminum alloy on the other side of the core An anode material is provided.

  Thus, by providing the brazing material on one side, it is easy to braze and join the plate material not provided with the brazing material, and by providing the sacrificial anode material on the other side, Corrosion resistance is improved.

According to the aluminum alloy material of the present invention , high strength and high corrosion resistance can be maintained over a long period of time even if the thickness is reduced. In particular, it has sufficient strength as a plate material or tube material for heat exchangers at high temperatures of 150 ° C. or higher.

The aluminum alloy brazing sheet according to the present invention can be formed into a plate material, a tube material, or the like, and can be easily processed into a heat exchanger or the like by brazing. Moreover, even if the thickness is reduced, high strength and high corrosion resistance can be maintained over a long period of time, and in particular, a heat exchanger having sufficient strength at a high temperature of 150 ° C. or higher can be obtained.

  Hereinafter, the best mode for realizing an aluminum alloy material and an aluminum alloy brazing sheet according to the present invention will be described. In FIG. 1, the structure of the cross section of the aluminum alloy brazing sheet which concerns on this invention is shown typically.

  The aluminum alloy material according to the present invention is an aluminum alloy material used as a core material 2 of an aluminum alloy brazing sheet 1 having a brazing material 3 on at least one side as shown in FIG. Cu: More than 1.5 mass% and 2.5 mass% or less is contained, and the balance is composed of Al and inevitable impurities. And as an inevitable impurity, it is controlled to Si: less than 0.2 mass% and Mn: less than 0.06 mass%. Below, the numerical range of content of each component which comprises the aluminum alloy material which concerns on this invention, and the reason for limitation of the numerical range are demonstrated.

(Cu: more than 1.5% by mass and 2.5% by mass or less)
Cu improves the strength by solid solution / precipitation strengthening in the aluminum alloy. Moreover, Cu has the effect of suppressing the strength reduction of the aluminum alloy material over time. Furthermore, since Cu has a function of making the potential noble, when the core material 2 of the aluminum alloy brazing sheet 1 is used, the potential of the core material can be made noble than the potential of the brazing material 3 by adding Cu. The brazing material 3 sacrifices the core material 2 (aluminum alloy material) and improves the corrosion resistance of the aluminum alloy brazing sheet 1. If the Cu content is 1.5% by mass or less, these effects are insufficient. On the other hand, if the Cu content exceeds 2.5% by mass, the self-corrosion resistance is lowered, and the corrosion resistance of the aluminum alloy material and the brazing sheet using the aluminum alloy material as a core material may be lowered. Accordingly, the Cu content is more than 1.5% by mass and not more than 2.5% by mass.

(Si: less than 0.2% by mass)
Si is usually mixed in an aluminum alloy as an inevitable impurity, and improves its strength by solid solution and precipitation strengthening in the aluminum alloy. However, when a large amount of Cu coexists, simple Si or When it precipitates as an Al-Cu-Si type compound and Si becomes 0.2 mass% or more, these precipitates will precipitate at a grain boundary, will generate intergranular corrosion, and will reduce corrosion resistance. Moreover, there exists a possibility that melting | fusing point of an aluminum alloy material may fall with Cu. Therefore, Si is restricted to less than 0.2% by mass.

(Mn: less than 0.06% by mass)
Mn crystallizes and precipitates as an intermetallic compound in an aluminum alloy and contributes to dispersion strengthening. However, when the large amount of Cu coexists, an Al—Mn—Cu-based compound is formed, and Mn is 0.06. If the content is greater than or equal to mass%, this compound may precipitate at the grain boundaries to cause intergranular corrosion and reduce the corrosion resistance. Therefore, Mn is restricted to less than 0.06% by mass.

  The aluminum alloy material according to the present invention further includes Fe: 0.05 to 1.5 mass%, Mg: 0.05 to 0.6 mass%, Ni: 0.05 to 1.5 mass%, Cr: 0 0.05-0.3 mass%, Ti: 0.05-0.3 mass%, Zr: 0.05-0.3 mass%, V: 0.05-0.3 mass%, Sn: 0.01 -0.1 mass%, Cd: 0.01-0.1 mass%, In: You may contain 1 or more types among 0.01-0.1 mass%.

(Fe: 0.05 to 1.5% by mass)
Fe crystallizes and precipitates as an intermetallic compound in the aluminum alloy and contributes to dispersion strengthening. Further, the crystallized and precipitated intermetallic compound serves as a nucleus for recrystallization and promotes recrystallization. Therefore, it has an effect of refining the structure and improves the workability of the aluminum alloy material. When the Fe content is less than 0.05% by mass, these effects cannot be obtained sufficiently. On the other hand, if the Fe content exceeds 1.5% by mass, the intermetallic compound is excessively crystallized and precipitated, thereby reducing the formability of the aluminum alloy material, and producing a coarse intermetallic compound. Corrosion resistance may be reduced. Therefore, the Fe content is 0.05 to 1.5 mass%.

(Mg: 0.05-0.6% by mass)
Similar to Cu, Mg improves the strength by solid solution and precipitation strengthening in an aluminum alloy. If the Mg content is less than 0.05% by mass, sufficient effects cannot be obtained. However, on the other hand, Mg has the effect of reducing flux brazing properties, so if the Mg content exceeds 0.6% by mass, brazing material is used when brazing in an atmosphere using a non-corrosive flux. Mg diffuses to 3 and the brazeability is significantly reduced. Moreover, the elongation of the parts (aluminum alloy material) before brazing may be reduced, and the formability may be reduced. Therefore, the Mg content is 0.05 to 0.6 mass%.

(Ni: 0.05 to 1.5% by mass)
Ni exists as an intermetallic compound in the aluminum alloy and contributes to dispersion strengthening. If the Ni content is less than 0.05% by mass, sufficient effects cannot be obtained. On the other hand, if the Ni content exceeds 1.5% by mass, the intermetallic compound becomes excessive and the moldability of the aluminum alloy material is lowered, and there is a possibility that a coarse intermetallic compound is produced and the corrosion resistance is lowered. is there. Therefore, the Ni content is 0.05 to 1.5 mass%.

(Cr, Zr, V: 0.05 to 0.3 mass% each)
Cr, Zr, and V each generate a fine intermetallic compound in an aluminum alloy and improve its strength. If the content is less than 0.05% by mass, the effect is not sufficiently obtained. On the other hand, if the content exceeds 0.3% by mass, a coarse intermetallic compound is formed and the forming processability of the aluminum alloy material is lowered. There is a risk of causing it. Therefore, the contents of Cr, Zr, and V are each 0.05 to 0.3 mass%.

(Ti: 0.05 to 0.3% by mass)
Ti produces | generates a fine intermetallic compound in an aluminum alloy, and improves the intensity | strength. In addition, this intermetallic compound is dispersed in layers. Since the Ti-Al intermetallic compound has a noble potential, the corrosion form is layered, and there is an effect that it is difficult to progress to corrosion (pitting corrosion) in the depth direction. If it is less than 0.05% by mass, these effects are small. On the other hand, when it exceeds 0.3 mass%, a coarse intermetallic compound may be produced | generated and there exists a possibility that a moldability may be reduced. Therefore, the content of Ti is set to 0.05 to 0.3% by mass.

(Sn, Cd, In: 0.01 to 0.1 mass% each)
Sn, Cd, and In contribute to the strength improvement by promoting the precipitation of Cu at a high temperature in the aluminum alloy. If each content is less than 0.01% by mass, the effect cannot be sufficiently obtained. On the other hand, if it exceeds 0.1% by mass, the strength is saturated, and even if more is added, the effect of improving the strength cannot be obtained, resulting in high raw material costs. Therefore, the contents of Sn, Cd, and In are each 0.01 to 0.1% by mass.

  Fe, Mg, Ni, Cr, Ti, Zr, V, Sn, Cd, and In may contain less than the specified content as an inevitable impurity. Even if these elements are contained in less than their respective specified contents, the performance of the aluminum alloy material according to the present invention is not hindered.

  In the aluminum alloy brazing sheet 1 according to the present invention, the brazing material 3 is provided on one side or both sides of the core material 2 made of the aluminum alloy material according to the present invention. Further, as shown in FIG. 1B, a brazing material 3 may be provided on one surface of the core material 2, and a sacrificial anode material 4 may be provided on the other surface. When producing a heat exchanger with such an aluminum alloy brazing sheet 1A provided with the sacrificial anode material 4, the surface provided with the sacrificial anode material 4 is formed to be on the corrosive environment side.

  As the brazing material 3 provided in the aluminum alloy brazing sheets 1 and 1A according to the present invention, an aluminum alloy that is usually used in brazing of an aluminum alloy can be used. Examples of such an aluminum alloy include an Al—Si based alloy, an Al—Si—Zn based alloy, an Al—Si—Mg (Bi) based alloy, and the like.

  As the sacrificial anode material 4 provided in the aluminum alloy brazing sheet 1A according to the present invention, a known material made of aluminum or an aluminum alloy can be used. Examples of the aluminum alloy include an Al—Zn alloy, an Al—Zn—Mg alloy, and an alloy obtained by adding Mn, Si, or the like to these.

  Further, in the aluminum alloy brazing sheet 1B according to the present invention, as shown in FIG. 1 (c), an intermediate layer 5 made of an aluminum alloy is inserted between the layer of the brazing material 3 and the core material 2, and the core material 2 It is good also as a Mg diffusion prevention layer to the brazing material 3 in the case of containing Mg. At this time, the sacrificial anode material 4 may be an intermediate layer. Moreover, it is good also as an aluminum alloy plate (clad material) for brazing provided with the sacrificial anode material 4 on one side or both sides of the core material 2. Such an aluminum alloy plate not provided with the brazing material 3 can be brazed to a brazing sheet provided with the brazing material.

  The aluminum alloy brazing sheet 1 (1A, 1B) according to the present invention is manufactured by a known cladding material manufacturing method. One example will be described below.

  First, an aluminum alloy as a component of the aluminum alloy material according to the present invention is melted and cast by continuous casting, and is subjected to face grinding and homogenization heat treatment as necessary to obtain a core material ingot. Further, the ingot for brazing material and, if necessary, the ingot for sacrificial anode material are obtained by the same method as the ingot for core material. The ingot for brazing material and the ingot for sacrificial anode material are each given a predetermined thickness by hot rolling or cutting to obtain an aluminum alloy plate for brazing material and an aluminum alloy plate for sacrificial anode material. If necessary, the core material ingot may be hot-rolled or cut to a predetermined thickness to form an aluminum alloy plate for the core material.

  Next, the brazing material aluminum alloy plate is superposed on the core material ingot (or the core material aluminum alloy plate) so as to have a predetermined cladding ratio, heated at a temperature of 400 ° C. or higher, and then subjected to pressure bonding by hot rolling. And plate material. Alternatively, the brazing material aluminum alloy plate is superposed on one surface side of the core material ingot (core material aluminum alloy plate) and the sacrificial anode material aluminum alloy plate is laminated on the other surface side so as to have a predetermined cladding ratio, In the same manner as above, pressure bonding is performed by hot rolling to obtain a plate material. Then, it is set as predetermined | prescribed plate | board thickness by performing roughening, cold rolling, intermediate annealing, and cold rolling as needed. Note that the cold rolling is repeated with intermediate annealing as appropriate until a desired thickness is obtained. Furthermore, after the cold rolling with the final thickness, finish annealing may be performed.

  Although the best mode for carrying out the present invention has been described above, an example in which the effect of the present invention has been confirmed will be specifically described below in comparison with a comparative example that does not satisfy the requirements of the present invention. . In addition, this invention is not limited to this Example.

(Sample preparation)
Aluminum alloys for core material (aluminum alloy material), brazing material (F), and sacrificial anode material (S) having the compositions shown in Table 1, Table 2, and Table 3 are prepared and melted and cast by continuous casting. Then, homogenization heat treatment and hot rolling were performed to obtain an aluminum alloy plate for core material, an aluminum alloy plate for brazing material, and an aluminum alloy plate for sacrificial anode material. Each aluminum alloy plate is overlapped in the combination shown in Table 1, and the brazing material and the sacrificial anode material are clad by hot rolling so that the thickness of each brazing material and sacrificial anode material is 10% of the total thickness of the plate, respectively, The thickness was 1.6 mm. Then, it refined to O material by finish annealing, and produced the 3 layer material (refer FIG. 1 (a), (b)) shown in Table 1. FIG.

(Evaluation of moldability)
A No. 5 test piece defined in JIS Z2201 was cut out from the produced three-layer material, and the material elongation was measured at room temperature with a tensile tester. The measurement results are shown in Table 1. The acceptable standard for molding processability was a material elongation of 26% or more.

The prepared three-layer material was cut into a strip shape having a width of 100 mm and a length of 200 mm, and a commercially available non-corrosive flux FL-7 (manufactured by Morita Chemical Co., Ltd.) 5 g / m ² was applied to the surface and dried. Then, the longitudinal direction was suspended vertically and held in a nitrogen atmosphere at 595 ° C. for 2 minutes to perform brazing heating to produce a brazing heat treatment material.

(Evaluation of high-temperature strength over time)
Evaluation of high-temperature strength over time was performed by cutting out a No. 5 test piece specified in JIS Z2201 from the brazed heat-treated material, holding the test piece at 180 ° C. for 300 hours, and then measuring the tensile strength at 180 ° C. with a tensile tester. It was done by doing. The measurement results are shown in Table 1. The acceptance criteria for the high temperature aging strength was a tensile strength of 145 MPa or more.

(Evaluation of corrosion resistance)
The corrosion resistance was evaluated by cutting out a 60 mm × 70 mm test piece from the brazing heat treatment material, using one side of the brazing material as the test surface, leaving the 50 mm × 60 mm test surface and covering the other surface and end surface with seal tape, and ASTM. The maximum corrosion depth 20 days after the SWAAT test specified in G85 was measured. The measurement results are shown in Table 1. The acceptable standard for corrosion resistance was a maximum corrosion depth of 250 μm or less.

In Reference Examples 1 to 3, since the Cu content in the core material is within the range of the present invention, the high temperature aging strength is sufficiently high. On the other hand, in Comparative Example 34, the Cu content was insufficient, so that the high temperature aging strength was not sufficiently obtained. On the other hand, since the comparative example 35 had excessive Cu content, corrosion resistance fell.

In Reference Examples 2 to 4, since the Si content in the core material is within the range of the present invention, the high temperature strength with time and the corrosion resistance are sufficiently high. On the other hand, in Comparative Example 36, since the Si content was excessive, intergranular corrosion occurred and the corrosion resistance decreased.

In Reference Examples 2 and 4, since the Mn content in the core material is within the range of the present invention, the high temperature strength with time and the corrosion resistance are sufficiently high. On the other hand, in Comparative Example 37, since the Mn content was excessive, intergranular corrosion occurred and the corrosion resistance decreased.

In Examples 5 , 15 , 21 , 28 , and 30, the Fe content in the core material is within the range of the present invention, so that the high temperature strength with time and the moldability are sufficiently high. On the other hand, since the comparative example 38 had excessive Fe content, the moldability and corrosion resistance were lowered.

  In Examples 6, 16, 22, 27, and 30, the Mg content in the core material is within the range of the present invention, and thus the high-temperature strength with time is sufficiently high. On the other hand, in Comparative Example 39, the Mg content is excessive, so that the moldability and corrosion resistance are reduced, the brazing property is lowered, and the surface of the brazing material of the brazing heat treatment material exhibits a brown color. The flow of the brazing material was uneven.

  In Examples 7, 17, 23, 28, and 30, the Ni content in the core material is within the range of the present invention, and therefore, the high temperature aging strength is sufficiently high. On the other hand, in Comparative Example 40, since the Ni content was excessive, molding processability and corrosion resistance were lowered.

In Examples 8 , 10 , 11 , 16-18 , 20 , 24-26 , 28-30, the Cr, Zr, V content in the core material is within the range of the present invention, respectively, so the high-temperature strength over time is sufficiently high. . On the other hand, since the comparative example 41 had excessive Cr content, the comparative example 43 had excessive Zr content, and the comparative example 44 had excessive V content, the molding processability was lowered.

  Examples 9, 15, 19, 25 to 27, and 30 have sufficiently high corrosion resistance because the Ti content in the core material is within the scope of the present invention. On the other hand, since the Ti content was excessive in Comparative Example 42, the moldability decreased.

  In Examples 12 to 14, 18 to 23, and 27 to 30, the Sn, Cd, and In contents in the core material are within the scope of the present invention, respectively, so that the high temperature aging strength is sufficiently high. On the other hand, Comparative Example 45 had Sn content, Comparative Example 46 had Cd content, and Comparative Example 47 had In content exceeding the range of the present invention. Compared with 12-14, the improvement of an effect was not seen about any of high temperature aging intensity | strength, shaping | molding workability, and corrosion resistance.

  In Examples 31 to 33, the brazing material on one side of Examples 2, 22 and 30 was changed to a sacrificial anode material, and as in Examples 2, 22 and 30, it is within the scope of the present invention. All of high-temperature strength over time, moldability, and corrosion resistance are sufficiently high.

It is sectional drawing which shows typically the structure of the aluminum alloy brazing sheet which concerns on this invention, (a) is embodiment of this invention, (b) is another embodiment of this invention, (c) is further this invention. It is another embodiment.

Explanation of symbols

1, 1A, 1B Aluminum alloy brazing sheet 2 Core material 3 Brazing material 4 Sacrificial anode material 5 Intermediate layer

Claims (3)

Aluminum alloy used as a core material of an aluminum alloy brazing sheet having a brazing material on at least one side and brazing heating at 595 ° C. for 2 minutes and then holding at 180 ° C. for 300 hours and then a tensile strength at 180 ° C. of 145 MPa or more Material,
Cu: more than 1.5% by mass and 2.5% by mass or less, Fe: 0.05-1.5% by mass, Mg: 0.05-0.6% by mass, Ni: 0.05 -1.5 mass%, Cr: 0.05-0.3 mass%, Ti: 0.05-0.3 mass%, Zr : 0.05-0.3 mass%, V: 0.05-0 .3 mass%, Sn: 0.01 to 0.1 mass%, Cd: 0.01 to 0.1 mass%, In: 0.01 to 0.1 mass%, or one selected from 2 Containing at least 1.87% by mass in total of the seeds, with the balance consisting of Al and inevitable impurities,
An aluminum alloy material characterized by being restricted to Si: less than 0.2 mass% and Mn: less than 0.06 mass% as the inevitable impurities. An aluminum alloy brazing sheet comprising the aluminum alloy material according to claim 1 as a core material and a brazing material made of an aluminum alloy on one or both surfaces thereof. An aluminum alloy comprising the aluminum alloy material according to claim 1 as a core, a brazing material made of an aluminum alloy on one side thereof, and a sacrificial anode material made of aluminum or an aluminum alloy on the other side of the core. Alloy brazing sheet.

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