JP2016169412A

JP2016169412A - Brazing sheet excellent in corrosion resistance after brazing

Info

Publication number: JP2016169412A
Application number: JP2015049461A
Authority: JP
Inventors: 翔石上; Sho Ishigami; 江戸　正和; Masakazu Edo; 正和江戸
Original assignee: Mitsubishi Aluminum Co Ltd
Current assignee: MA Aluminum Corp
Priority date: 2015-03-12
Filing date: 2015-03-12
Publication date: 2016-09-23
Anticipated expiration: 2035-03-12
Also published as: JP6624417B2

Abstract

PROBLEM TO BE SOLVED: To provide a brazing sheet excellent in corrosion resistance after brazing.SOLUTION: The invention relates to an aluminum alloy brazing sheet having sheet thickness of 0.18 mm or less by cladding a sacrificial material on a single side face of a core material and a brazing material on another side face, where the core material consists of an Al-Mn-Si-based aluminum alloy containing, by mass%, Cu:0.5 to 1.3%, the sacrificial material consists of an aluminum alloy containing, by mass%, Zn:4.0 to 7.0%, Mn:1.0 to 1.8%, Si:0.2 to 1.2% and the balance Al with inevitable impurities, the brazing material consists of an aluminum alloy containing Si:6.0 to 11.0% and Zn:0.1 to 3.0% and the balance Al with inevitable impurities and an area with potential difference from most rare potential of the core material of 100 mV or more is 10% to 50% of the material sheet thickness in a corrosion potential after a brazing heat treatment.SELECTED DRAWING: Figure 4

Description

本発明は、熱交換器などに使用されるろう付け後の耐食性に優れるブレージングシートに関するものである。 The present invention relates to a brazing sheet having excellent corrosion resistance after brazing used for a heat exchanger or the like.

従来から、アルミニウム合金製の自動車用熱交換器が知られている。この熱交換器は、例えばアウターフィン、チューブ、ヘッダープレート、サイドサポートなどの部材から構成されている。また、自動車用熱交換器は、一般に、フッ化物系フラックスを用い、６００℃前後の温度でなされるろう付け処理により前記の各部材を接合して製品化される。 2. Description of the Related Art Conventionally, aluminum automotive heat exchangers are known. This heat exchanger is comprised from members, such as an outer fin, a tube, a header plate, a side support, for example. Moreover, the heat exchanger for motor vehicles is generally commercialized by joining each of the above-mentioned members by a brazing process using a fluoride-based flux at a temperature of about 600 ° C.

また、熱交換器を構成するチューブやヘッダープレートがブレージングシートから構成されることがある。
このブレージングシートとして、例えば、Ｍｎ、Ｃｕ、Ｓｉ、Ｆｅを規定の範囲含有させたアルミニウム合金で構成される芯材の一方の面に、Ａｌ−Ｓｉ系合金のろう材を貼り合わせ、他方の面に、芯材より電気化学的に卑なアルミニウム合金の犠牲材（内張材）を貼り合せた構成が知られている（例えば特許文献１、特許文献２参照）。
ここで用いる犠牲材は前記芯材よりも電気化学的に卑な材料とすることにより、犠牲陽極材として機能し、芯材の腐食を防止することができる。 Moreover, the tube and header plate which comprise a heat exchanger may be comprised from a brazing sheet.
As this brazing sheet, for example, an Al-Si alloy brazing material is bonded to one side of a core material made of an aluminum alloy containing Mn, Cu, Si, Fe in a specified range, and the other side. In addition, a structure in which a sacrificial material (lining material) of an aluminum alloy that is electrochemically lower than the core material is bonded (see, for example, Patent Document 1 and Patent Document 2).
The sacrificial material used here can function as a sacrificial anode material and prevent corrosion of the core material by using a material that is electrochemically lower than the core material.

特開平９−２９５０８９号公報Japanese Patent Laid-Open No. 9-295089 特開２０１２−１１７１０７号公報JP 2012-117107 A

前述のブレージングシートには、例えば、熱交換器の小型化や高性能化により、更なる材料の薄肉化が要求されている。
この薄肉化した材料へ従来工法と同様のろう付け熱処理を施した場合、犠牲材に添加されたＺｎの芯材内部への拡散および芯材に添加されたＣｕの犠牲材、ろう材への拡散が促進される。
このため、チューブ内面側と外面側の芯材に対する孔食電位差が減少し、耐食性が低下し、材料へ早期に貫通孔が発生することが問題となっている。 The brazing sheet described above is required to have a thinner material due to, for example, downsizing and higher performance of the heat exchanger.
When this thinned material is subjected to the same brazing heat treatment as in the conventional method, diffusion of Zn added to the sacrificial material into the core material and diffusion of Cu added to the core material to the sacrificial material and brazing material Is promoted.
For this reason, the pitting corrosion potential difference with respect to the core material of the tube inner surface side and the outer surface side is reduced, the corrosion resistance is lowered, and there is a problem that through holes are generated early in the material.

本発明は、以上のような事情に鑑みてなされたものであり、薄肉構造のろう付け構造とした熱交換器に適用された場合であっても強度が高く、耐食性に優れるブレージングシートを提供することを目的とする。 The present invention has been made in view of the above circumstances, and provides a brazing sheet having high strength and excellent corrosion resistance even when applied to a heat exchanger having a thin-walled brazing structure. For the purpose.

本発明は前記課題を解決するために、芯材の一方の面に犠牲材を、他方の面にろう材をクラッドしたアルミニウム合金ブレージングシートであって、前記芯材が質量％でＣｕ：０．５〜１．３％を含有するＡｌ−Ｍｎ−Ｓｉ系アルミニウム合金からなり、前記犠牲材が質量％でＺｎ：４．０〜７．０％、Ｍｎ：１．０〜１．８％、Ｓｉ：０．２〜１．２％含有し、残部がＡｌおよび不可避不純物からなるアルミニウム合金からなり、前記ろう材が質量％でＳｉ：６．０〜１１．０％、Ｚｎ：０．１〜３．０％含有し、残部がＡｌおよび不可避不純物からなるアルミニウム合金からなり、ろう付熱処理後の孔食電位において、前記ブレージングシートの厚さ方向に沿って孔食電位を測定した場合、芯材の最も貴な電位との電位差を１００ｍＶ以上とする領域の厚さが、前記ブレージングシートの材料板厚の１０％〜５０％となることを特徴とする板厚が０．１８ｍｍ以下のアルミニウム合金ブレージングシートに関する。 In order to solve the above problems, the present invention provides an aluminum alloy brazing sheet in which a sacrificial material is clad on one surface of a core material and a brazing material is clad on the other surface, and the core material is Cu: 0. It is made of an Al—Mn—Si based aluminum alloy containing 5 to 1.3%, and the sacrificial material is Zn: 4.0 to 7.0% by mass, Mn: 1.0 to 1.8%, Si : 0.2-1.2% contained, the balance is made of an aluminum alloy composed of Al and inevitable impurities, and the brazing filler material is Si: 6.0 to 11.0%, Zn: 0.1 to 3% by mass When the pitting corrosion potential is measured along the thickness direction of the brazing sheet at the pitting corrosion potential after brazing heat treatment, the balance is made of the core material. The potential difference from the most precious potential is 100mV or less The thickness of the area to the plate thickness, characterized by comprising 10% to 50% of the material thickness of the brazing sheet is on the following aluminum alloy brazing sheet 0.18 mm.

本発明において、前記芯材がさらに、質量％でＭｎ：０．５〜１．８％、Ｓｉ：０．０５〜１．３％、Ｆｅ：０．０５〜０．５％、Ｍｇ：０．０５〜０．５％、Ｚｒ：０．０５〜０．３％、Ｔｉ：０．０５〜０．３％、Ｃｒ：０．０５〜０．３％から選択される１種または２種以上をさらに含有する構成を採用できる。
本発明において、ろう付熱処理後の孔食電位において、前記芯材の最も貴な電位との電位差を１００ｍＶ以上とする領域の中で、前記犠牲材界面から前記芯材の板厚方向に向かった領域の長さをＡμｍ、前記ろう材界面から前記芯材の板厚方向に向かった領域の長さをＢμｍとした時、１＜（Ａ＋１）／（Ｂ＋１）＜６１の関係となることが好ましい。 In the present invention, the core material may further contain, in mass%, Mn: 0.5 to 1.8%, Si: 0.05 to 1.3%, Fe: 0.05 to 0.5%, Mg: 0.00. One or more selected from 05 to 0.5%, Zr: 0.05 to 0.3%, Ti: 0.05 to 0.3%, Cr: 0.05 to 0.3% Furthermore, the structure which contains can be employ | adopted.
In the present invention, the pitting corrosion potential after brazing heat treatment is directed from the sacrificial material interface toward the thickness of the core material in a region where the potential difference from the most noble potential of the core material is 100 mV or more. When the length of the region is A μm and the length of the region from the brazing material interface in the thickness direction of the core material is B μm, it is preferable that 1 <(A + 1) / (B + 1) <61. .

本発明において、ろう付熱処理後の芯材と犠牲材の孔食電位差が１６０〜２９０ｍＶの範囲にあることが好ましい。
本発明において、ろう付熱処理後のＺｎ濃度０．２％以下の領域が、材料板厚の２０％〜７０％となることが好ましい。 In the present invention, the difference in pitting corrosion potential between the core material and the sacrificial material after brazing heat treatment is preferably in the range of 160 to 290 mV.
In the present invention, the region having a Zn concentration of 0.2% or less after the brazing heat treatment is preferably 20% to 70% of the material plate thickness.

本発明ではアルミニウム合金の化学成分をブレージングシートの薄肉化に対応した高耐食材とするとともに、薄肉材に適したろう付熱処理が施された場合に犠牲材へ添加されたＺｎや芯材に添加されたＣｕの元素拡散状態を制御でき、犠牲材およびろう材と芯材間の孔食電位差を適正化し、犠牲材側とろう材側の電位バランスを最適な関係とすることで従来よりも薄肉化した場合であっても優れた耐食性を有するブレージングシートを提供することができる。 In the present invention, the chemical composition of the aluminum alloy is made to be a highly corrosion-resistant material corresponding to the thinning of the brazing sheet, and is added to Zn and the core material added to the sacrificial material when brazing heat treatment suitable for the thin-walled material is performed. The element diffusion state of Cu can be controlled, the pitting corrosion potential difference between the sacrificial material and the brazing material and the core material is optimized, and the potential balance between the sacrificial material side and the brazing material side is optimized to make the thickness thinner than before. Even in such a case, a brazing sheet having excellent corrosion resistance can be provided.

本発明の一実施形態である熱交換器に採用されるブレージングシートの断面図。Sectional drawing of the brazing sheet employ | adopted as the heat exchanger which is one Embodiment of this invention. 図１に示すブレージングシートを用いて形成したチューブの一例を示す断面図。Sectional drawing which shows an example of the tube formed using the brazing sheet shown in FIG. 同ブレージングシートを用いて構成された熱交換器の一部を断面とした斜視図。The perspective view which made some cross sections the heat exchanger comprised using the brazing sheet. 実施例において得られた試料における犠牲材表面からの距離と孔食電位の関係を示すグラフ。The graph which shows the relationship from the distance from the sacrificial material surface in the sample obtained in the Example, and a pitting corrosion potential. 従来例において得られた試料における犠牲材表面からの距離と孔食電位の関係を示すグラフ。The graph which shows the distance from the sacrificial material surface in the sample obtained in the prior art example, and the relationship of a pitting corrosion potential. 実施例において得られた試料における犠牲材表面からの距離とＺｎ濃度の関係を示すグラフ。The graph which shows the relationship from the distance from the sacrificial material surface and Zn density | concentration in the sample obtained in the Example. 従来例において得られた試料における犠牲材表面からの距離とＺｎ濃度の関係を示すグラフ。The graph which shows the relationship between the distance from the sacrificial material surface and Zn density | concentration in the sample obtained in the prior art example.

以下、本発明に係るブレージングシートの第１実施形態について図面を参照しながら説明する。
なお、以下の説明で用いる図面は、特徴部分を強調する目的で、便宜上特徴となる部分を拡大して示している場合があり、各構成要素の寸法比率などが実際と同じであるとは限らない。また、同様の目的で、特徴とならない部分を省略して図示している場合がある。 Hereinafter, a first embodiment of a brazing sheet according to the present invention will be described with reference to the drawings.
In the drawings used in the following description, for the purpose of emphasizing the feature portion, the feature portion may be shown in an enlarged manner for convenience, and the dimensional ratios of the respective constituent elements are not always the same as in practice. Absent. In addition, for the same purpose, portions that are not characteristic may be omitted from illustration.

図１は本実施形態のブレージングシート１の断面図である。このブレージングシート１は、アルミニウム合金からなる芯材１ａと、この芯材１ａの一面側に被着（クラッド圧着）されたアルミニウム合金からなる層状のろう材１ｂと、芯材１ａの他面側に被着（クラッド圧着）されたアルミニウム合金からなる層状の犠牲材１ｃを主体として構成されている。図1に示すブレージングシート１を例えばＢ型に成形して図２に示すＢ型のチューブ１０が形成され、このチューブ１０を例えば図３に示すように組み込んで熱交換器２０が構成される。 FIG. 1 is a cross-sectional view of a brazing sheet 1 of the present embodiment. This brazing sheet 1 is composed of a core material 1a made of an aluminum alloy, a layered brazing material 1b made of an aluminum alloy deposited on one surface side of the core material 1a, and on the other surface side of the core material 1a. The main component is a layered sacrificial material 1c made of a deposited (clad pressure bonded) aluminum alloy. The brazing sheet 1 shown in FIG. 1 is formed into, for example, a B type to form a B type tube 10 shown in FIG. 2, and the tube 10 is assembled as shown in FIG.

チューブ１０は、例えば、図２に示すように、前記ブレージングシート１を成形ロール等により犠牲材１ｃを内側に、ろう材１ｂを外側になるように偏平管状に成形しながらブレージングシート端縁を突合せ部分としてＢ型のチューブ１０を構成できる。 For example, as shown in FIG. 2, the tube 10 is butted against the edge of the brazing sheet while forming the brazing sheet 1 into a flat tube so that the sacrificial material 1c is on the inside and the brazing material 1b is on the outside with a forming roll or the like. A B-type tube 10 can be constructed as a part.

熱交換器２０は、例えば自動車のラジエータ等に用いられる構造とされ、チューブ１０と、ヘッダー２１と、アウターフィン２２と、サイドサポート２３とから概略構成されている。
ヘッダー２１とチューブ１０とは、ヘッダー２１に複数整列形成されたスロット（差込孔）２１ａに各チューブ１０の端部を差し込み、差込部分の周りに配置したろう材１ｂを用いて両者を相互にろう付けすることで接合されている。また、チューブ１０とアウターフィン２２は、チューブ１０を構成するブレージングシート１に設けられたろう材１ｂを用いて、両者を相互にろう付けすることで接合されている。
なお、チューブ１０を形成する際のブレージングシート１の端部１０Ａ、１０Ａのろう付け（図２参照）と、ヘッダー２１とチューブ１０のろう付けと、チューブ１０とアウターフィン２２のろう付けは熱交換器２０の組み立て時に同時に行うことができる。 The heat exchanger 20 has a structure used for, for example, a radiator of an automobile, and includes a tube 10, a header 21, an outer fin 22, and a side support 23.
The header 21 and the tube 10 are connected to each other by using the brazing material 1b arranged around the insertion portion by inserting the end portion of each tube 10 into a plurality of slots (insertion holes) 21a formed in the header 21. It is joined by brazing. Moreover, the tube 10 and the outer fin 22 are joined by brazing together using the brazing material 1b provided in the brazing sheet 1 which comprises the tube 10. FIG.
Note that brazing of the end portions 10A and 10A of the brazing sheet 1 when forming the tube 10 (see FIG. 2), brazing of the header 21 and the tube 10, and brazing of the tube 10 and the outer fin 22 are heat exchange. This can be done simultaneously with the assembly of the vessel 20.

次に、本実施形態のブレージングシート１を構成する芯材１ａ、ろう材１ｂ、犠牲材１ｃの組成について説明する。
ブレージングシート１において、芯材１ａが質量％でＣｕ：０．５〜１．３％を含有するＡｌ−Ｍｎ−Ｓｉ系アルミニウム合金からなり、犠牲材１ｃが質量％でＺｎ：４．０〜７．０％、Ｍｎ：１．０〜１．８％、Ｓｉ：０．２〜１．２％含有し、残部がＡｌおよび不可避不純物からなるアルミニウム合金からなり、ろう材１ｂが質量％でＳｉ：６．０〜１１．０％、Ｚｎ：０．１〜３．０％含有し、残部がＡｌおよび不可避不純物からなるアルミニウム合金からなる。
なお、本明細書において組成比の上限と下限を０．５〜１．３％のように表記した場合、特に説明しない限り上限と下限を含むものとする。よって、０．５〜１．３％は０．５％以上、１．３％以下の範囲であることを意味する。 Next, the composition of the core material 1a, the brazing material 1b, and the sacrificial material 1c constituting the brazing sheet 1 of the present embodiment will be described.
In the brazing sheet 1, the core material 1a is made of an Al—Mn—Si based aluminum alloy containing Cu: 0.5 to 1.3% by mass%, and the sacrificial material 1c is Zn: 4.0 to 7 by mass%. 0.0%, Mn: 1.0 to 1.8%, Si: 0.2 to 1.2%, the balance is made of an aluminum alloy consisting of Al and inevitable impurities, and the brazing filler metal 1b is Si: It is made of an aluminum alloy containing 6.0 to 11.0%, Zn: 0.1 to 3.0%, with the balance being Al and inevitable impurities.
In the present specification, when the upper and lower limits of the composition ratio are expressed as 0.5 to 1.3%, the upper and lower limits are included unless otherwise specified. Therefore, 0.5 to 1.3% means a range of 0.5% or more and 1.3% or less.

芯材１ａを構成するアルミニウム合金について、上述の組成に加え、質量％でＭｎ：０．５〜１．８％、Ｓｉ：０．０５〜１．３％、Ｆｅ：０．０５〜０．５％、Ｍｇ：０．０５〜０．５％、Ｚｒ：０．０５〜０．３％、Ｔｉ：０．０５〜０．３％、Ｃｒ：０．０５〜０．３％から選択される１種または２種以上をさらに含有する組成を採用できる。 About the aluminum alloy which comprises the core material 1a, in addition to the above-mentioned composition, Mn: 0.5-1.8%, Si: 0.05-1.3%, Fe: 0.05-0.5 by the mass% %, Mg: 0.05 to 0.5%, Zr: 0.05 to 0.3%, Ti: 0.05 to 0.3%, Cr: 0.05 to 0.3% 1 The composition which further contains a seed | species or 2 or more types is employable.

以下、各成分について説明する。
＜芯材成分＞
［Ｃｕ：０．５〜１．３質量％］
Ｃｕは、マトリックス中に固溶し、アルミニウム合金を高強度化する作用があるが、Ｃｕ含有量が０．５質量％未満では強度が不足し、Ｃｕ含有量が１．３質量％を超えると耐食性を低下させる。このため、Ｃｕ含有量は０．５〜１．３質量％が望ましく、０．８〜１．２質量％の範囲がより好ましい。
［Ｍｎ：０．５〜１．８質量％］
Ｍｎはマトリックス中にＡｌ−Ｍｎ−Ｓｉ系、Ａｌ−Ｍｎ−Ｆｅ系、Ａｌ−Ｍｎ−Ｆｅ−Ｓｉ系金属間化合物を微細に形成し、材料強度を高める効果がある。しかし、Ｍｎ量が０．５質量％未満ではその効果が充分に発揮されず、１．８質量％を超えると鋳造時に巨大な金属間化合物を生成するため材料の成形性が低下する。なお、同様の理由からＭｎ含有量について、１．０〜１．７５質量％とすることがより望ましい。 Hereinafter, each component will be described.
<Core material component>
[Cu: 0.5 to 1.3% by mass]
Cu dissolves in the matrix and has the effect of increasing the strength of the aluminum alloy. However, when the Cu content is less than 0.5% by mass, the strength is insufficient, and when the Cu content exceeds 1.3% by mass. Reduces corrosion resistance. For this reason, as for Cu content, 0.5-1.3 mass% is desirable, and the range of 0.8-1.2 mass% is more preferable.
[Mn: 0.5 to 1.8% by mass]
Mn has the effect of increasing the material strength by forming Al—Mn—Si, Al—Mn—Fe, and Al—Mn—Fe—Si intermetallic compounds in the matrix. However, if the amount of Mn is less than 0.5% by mass, the effect is not sufficiently exhibited. If it exceeds 1.8% by mass, a huge intermetallic compound is produced at the time of casting, so that the formability of the material is lowered. For the same reason, the Mn content is more preferably 1.0 to 1.75% by mass.

［Ｓｉ：０．０５〜１．３質量％］
Ｓｉはマトリックス中にＡｌ−Ｍｎ−Ｓｉ系、Ａｌ−Ｍｎ−Ｆｅ−Ｓｉ系金属間化合物を微細に形成し、材料強度を高める効果がある。しかし、Ｓｉ量が０．０５質量％未満ではその効果が充分に発揮されず、１．３質量％を超えると材料の融点が低下する。なお同様の理由からＳｉ含有量について、０．５〜１．１質量％とすることがより望ましい。 [Si: 0.05 to 1.3% by mass]
Si has the effect of increasing the material strength by forming Al—Mn—Si and Al—Mn—Fe—Si intermetallic compounds in the matrix. However, if the amount of Si is less than 0.05% by mass, the effect is not sufficiently exhibited, and if it exceeds 1.3% by mass, the melting point of the material is lowered. For the same reason, the Si content is more preferably 0.5 to 1.1% by mass.

［Ｆｅ：０．０５〜０．５質量％］
Ｆｅはマトリックス中にＡｌ−Ｍｎ−Ｆｅ系、Ａｌ−Ｍｎ−Ｆｅ−Ｓｉ系金属間化合物を微細に形成し、材料強度を高める効果がある。しかし、Ｆｅ量が０．０５質量％未満では鋳造性が低下し、０．５質量％を超えると鋳造時に巨大な金属間化合物を生成して材料の成形性が低下する。なお、同様の理由によりＦｅ含有量について０．２〜０．４質量％とすることがより望ましい。 [Fe: 0.05 to 0.5% by mass]
Fe has an effect of increasing material strength by forming Al—Mn—Fe and Al—Mn—Fe—Si intermetallic compounds in the matrix. However, if the amount of Fe is less than 0.05% by mass, the castability deteriorates, and if it exceeds 0.5% by mass, a huge intermetallic compound is produced during casting and the formability of the material is deteriorated. For the same reason, the Fe content is more preferably 0.2 to 0.4% by mass.

[Ｍｇ：０．０５〜０．５質量％]
Ｍｇは、材料強度を高める効果がある。しかし、Ｍｇ量が０．０５質量％未満ではその効果が充分に発揮されず、０．５質量％を超えるとろう付け性が低下する。なお、同様の理由によりＭｇ含有量について０．１〜０．４質量％とすることがより望ましい。
[Ｚｒ：０．０５〜０．３質量％、Ｔｉ：０．０５〜０．３質量％、Ｃｒ：０．０５〜０．３質量％]
Ｚｒ、Ｔｉ、Ｃｒはアルミニウム合金の高強度化に寄与するが、いずれも個々に０．０５質量％未満の添加では高強度化に不足となり、０．３質量％を超える添加では成形性が劣るようになる。 [Mg: 0.05 to 0.5% by mass]
Mg has the effect of increasing the material strength. However, when the amount of Mg is less than 0.05% by mass, the effect is not sufficiently exhibited, and when it exceeds 0.5% by mass, the brazing property is lowered. For the same reason, the Mg content is more preferably 0.1 to 0.4% by mass.
[Zr: 0.05 to 0.3% by mass, Ti: 0.05 to 0.3% by mass, Cr: 0.05 to 0.3% by mass]
Zr, Ti, and Cr contribute to increasing the strength of the aluminum alloy, but any of the additions of less than 0.05% by mass is insufficient to increase the strength, and the addition of more than 0.3% by mass results in poor formability. It becomes like this.

＜ろう材成分＞
チューブ１０のろう材１ｂは、Ｓｉを６．０〜１１．０質量％、Ｚｎを０．１〜３．０質量％含有し、残部がアルミニウム及び不可避的不純物のアルミニウム合金からなる。
［Ｓｉ：６．０〜１１．０質量％］
ろう材１ｂ中に含まれるＳｉは融点を下げると共に流動性を付与する成分であり、その含有量が６質量％未満では所望の効果が不十分であり、一方、１１質量％を越えて含有するとかえって流動性が低下するので好ましくない。したがって、ろう材１ｂ中のＳｉの含有量は６．０〜１１．０質量％の範囲が好ましい。 <Brass component>
The brazing material 1b of the tube 10 contains 6.0 to 11.0% by mass of Si, 0.1 to 3.0% by mass of Zn, and the balance is made of aluminum and an inevitable impurity aluminum alloy.
[Si: 6.0 to 11.0% by mass]
Si contained in the brazing filler metal 1b is a component that lowers the melting point and imparts fluidity. If the content is less than 6% by mass, the desired effect is insufficient. On the other hand, if the content exceeds 11% by mass, On the contrary, it is not preferable because the fluidity is lowered. Therefore, the content of Si in the brazing material 1b is preferably in the range of 6.0 to 11.0% by mass.

［Ｚｎ：０．１〜３．０質量％］
Ｚｎは、アルミニウム合金の電位を卑にする作用があり、ろう材１ｂに添加した場合、芯材１ａとの電位差が大きくなり、耐食性に有効な電位勾配ができることで、耐食性を向上させ、腐食深さを低減する効果がある。しかし、Ｚｎ量が０．１質量％未満ではその効果が充分に発揮されず、３．０質量％を超えると、ろう材１ｂの電位が卑となりすぎる。 [Zn: 0.1 to 3.0% by mass]
Zn has the effect of lowering the potential of the aluminum alloy, and when added to the brazing material 1b, the potential difference from the core material 1a is increased, and a potential gradient effective for corrosion resistance is created, thereby improving the corrosion resistance and increasing the corrosion depth. There is an effect of reducing the thickness. However, if the amount of Zn is less than 0.1% by mass, the effect is not sufficiently exhibited, and if it exceeds 3.0% by mass, the potential of the brazing material 1b becomes too low.

＜犠牲材成分＞
チューブ１０の犠牲材１ｃは、Ｚｎを４．０〜７．０質量％、Ｍｎを１．０〜１．８質量％、Ｓｉを０．２〜１．２質量％含有し、残部がアルミニウム及び不可避的不純物の組成を有するアルミニウム合金からなることが好ましい。
［Ｚｎ：４．０〜７．０質量％］
Ｚｎはアルミニウム合金の電位を卑にする作用があり、犠牲材１ｃに添加した場合、芯材１ａとの電位差が大きくなり、耐食性に有効な電位勾配ができることで、ブレージングシート１（即ちチューブ１０）の耐食性を向上させ、腐食深さを低減する効果がある。
しかし、Ｚｎ量が４．０質量％未満ではその効果が充分に発揮されず、７．０質量％を超えると腐食速度が速くなりすぎることで犠牲材１ｃが早期に消失し、腐食深さが増加する。なお、同様の理由により、Ｚｎ含有量について、４．５〜６．５質量％とすることがより望ましい。
［Ｍｎ：１．０〜１．８質量％］
Ｍｎはマトリックス中にＡｌ−Ｍｎ−Ｓｉ系、Ａｌ−Ｍｎ−Ｆｅ系、Ａｌ−Ｍｎ−Ｆｅ−Ｓｉ系金属間化合物を微細に形成し、材料強度を高める効果がある。しかし、Ｍｎ量が１．０質量％未満ではその効果が充分に発揮されず、１．８質量％を超えると鋳造時に巨大な金属間化合物を生成するため材料の成形性が低下する。なお、同様の理由からＭｎ含有量について、１．１〜１．７５質量％とすることがより望ましい。 <Sacrificial material component>
The sacrificial material 1c of the tube 10 contains 4.0 to 7.0% by mass of Zn, 1.0 to 1.8% by mass of Mn, 0.2 to 1.2% by mass of Si, with the balance being aluminum and It is preferably made of an aluminum alloy having a composition of inevitable impurities.
[Zn: 4.0 to 7.0% by mass]
Zn has the effect of lowering the potential of the aluminum alloy, and when added to the sacrificial material 1c, the potential difference from the core material 1a increases, and a potential gradient effective for corrosion resistance can be formed, so that the brazing sheet 1 (that is, the tube 10). Has the effect of improving the corrosion resistance and reducing the corrosion depth.
However, when the Zn content is less than 4.0% by mass, the effect is not sufficiently exerted. When the Zn content exceeds 7.0% by mass, the corrosion rate becomes too fast, so that the sacrificial material 1c disappears early, and the corrosion depth is low. To increase. For the same reason, the Zn content is more preferably 4.5 to 6.5% by mass.
[Mn: 1.0 to 1.8% by mass]
Mn has the effect of increasing the material strength by forming Al—Mn—Si, Al—Mn—Fe, and Al—Mn—Fe—Si intermetallic compounds in the matrix. However, if the amount of Mn is less than 1.0% by mass, the effect is not sufficiently exhibited. If the amount of Mn exceeds 1.8% by mass, a huge intermetallic compound is produced at the time of casting, so that the formability of the material is lowered. For the same reason, the Mn content is more preferably 1.1 to 1.75% by mass.

［Ｓｉ：０．２〜１．２質量％］
ＳｉはＭｇと微細なＭｇ−Ｓｉ化合物を形成することで材料の強度を向上させる効果がある。しかし、Ｓｉ量が０．２質量％未満ではその効果が充分に発揮されず、１．２質量％を超えると材料の融点が低下する。なお同様の理由からＳｉ含有量を０．４〜１．０質量％とすることがより望ましい。 [Si: 0.2 to 1.2% by mass]
Si has the effect of improving the strength of the material by forming a fine Mg-Si compound with Mg. However, if the amount of Si is less than 0.2% by mass, the effect is not sufficiently exhibited, and if it exceeds 1.2% by mass, the melting point of the material is lowered. For the same reason, the Si content is more preferably 0.4 to 1.0% by mass.

＜電位の順列＞
本実施形態のブレージングシート１においては、ろう付熱処理後の孔食電位において、芯材１の最も貴な電位との電位差を１００ｍＶ以上とする領域が、ブレージングシート1の材料板厚の１０％〜５０％とされている。
更に、ろう付熱処理後の孔食電位において、芯材１ａの最も貴な電位との電位差を１００ｍＶ以上とした領域の中で、犠牲材１ｃの最表面から芯材１ａ板厚方向に向かった領域の長さ（厚さ）をＡμｍ、ろう材１ｂの最表面から板厚方向に向かった領域の長さ（厚さ）をＢμｍとした時、１＜（Ａ＋１）／（Ｂ＋１）＜６１の関係とされている。 <Permutation of potential>
In the brazing sheet 1 of the present embodiment, in the pitting corrosion potential after the brazing heat treatment, the region where the potential difference from the most noble potential of the core material 1 is 100 mV or more is 10% to the material plate thickness of the brazing sheet 1. 50%.
Further, in the pitting corrosion potential after brazing heat treatment, the region from the outermost surface of the sacrificial material 1c toward the thickness direction of the core material 1a in the region where the potential difference from the most noble potential of the core material 1a is 100 mV or more The relationship of 1 <(A + 1) / (B + 1) <61 where Aμm is the length (thickness) and Bμm is the length (thickness) of the region from the outermost surface of the brazing material 1b toward the plate thickness direction. It is said that.

図４にこれらの関係の概要を示す。図４はブレージングシート1において犠牲材最表面からの距離を横軸に、孔食電位を縦軸にした場合、即ち、ブレージングシート１の横断面に沿ってブレージングシート１の芯材１ａとろう材１ｂと犠牲材１ｃの全体を含めた厚さ方向の位置毎の孔食電位を示す。
芯材１ａの最も貴な電位の位置は孔食電位を示すカーブのピークの位置であり、図４に鎖線ａで示し、芯材１ａの最も貴な電位との電位差を１００ｍＶとする位置を鎖線ｂで示す。芯材１ａの最も貴な電位との電位差を１００ｍＶ以上とした領域の中で、犠牲材１ｃの最表面から芯材１ａ板厚方向に向かった領域の長さ（厚さ）を図４にＡで示し、芯材１ａの最も貴な電位との電位差を１００ｍＶ以上とした領域の中で、ろう材１ｂの最表面から板厚方向に向かった領域の長さ（厚さ）を図４にＢで示す。図４において、横軸の左端の位置が犠牲材１ｃの外表面位置を示し、曲線の右端の位置がろう材１ｂの外表面位置を示す。
また、ろう付熱処理後の前記芯材１ａと前記犠牲材１ｂの孔食電位差が１６０〜２９０ｍＶとなる範囲は図１の鎖線ａと鎖線ｃの間の範囲を示す。 FIG. 4 shows an outline of these relationships. FIG. 4 shows the case where the distance from the outermost surface of the sacrificial material is plotted on the horizontal axis and the pitting corrosion potential is plotted on the vertical axis in the brazing sheet 1, that is, along the cross section of the brazing sheet 1. The pitting corrosion potential for each position in the thickness direction including 1b and the entire sacrificial material 1c is shown.
The position of the most noble potential of the core material 1a is the peak position of the curve indicating the pitting corrosion potential, and is indicated by a chain line a in FIG. 4, and the position where the potential difference from the most noble potential of the core material 1a is 100 mV Indicated by b. FIG. 4 shows the length (thickness) of the region from the outermost surface of the sacrificial material 1c in the thickness direction of the core material 1a in the region where the potential difference from the most noble potential of the core material 1a is 100 mV or more. The length (thickness) of the region from the outermost surface of the brazing material 1b toward the plate thickness direction in the region where the potential difference from the most noble potential of the core material 1a is 100 mV or more is shown in FIG. It shows with. In FIG. 4, the position of the left end of the horizontal axis indicates the outer surface position of the sacrificial material 1c, and the position of the right end of the curve indicates the outer surface position of the brazing material 1b.
Moreover, the range in which the pitting corrosion potential difference between the core material 1a and the sacrificial material 1b after brazing heat treatment is 160 to 290 mV is the range between the chain line a and the chain line c in FIG.

このような孔食電位の電位勾配を生じるのは、ろう付け時に犠牲材１ｃに含まれていた元素が拡散し、特にＺｎが拡散することで芯材１ａにＺｎ濃度に応じた電位勾配が生じることによる。
なお、図４に示す電位勾配となるのは、本実施形態で先に説明した芯材用のアルミニウム合金組成と犠牲材用アルミニウム合金組成を採用していることに加え、ろう付け条件などを調整していることによる。
上述のような孔食電位の電位バランスを有することによって、ブレージングシート１の耐食性を高め、貫通孔が発生することを防ぐことができる。 The potential gradient of the pitting corrosion potential is caused by the diffusion of elements contained in the sacrificial material 1c at the time of brazing. In particular, the diffusion of Zn causes a potential gradient according to the Zn concentration in the core material 1a. It depends.
The potential gradient shown in FIG. 4 is adjusted in addition to adopting the aluminum alloy composition for the core material and the aluminum alloy composition for the sacrificial material described earlier in this embodiment, and the brazing conditions are adjusted. It depends on what you are doing.
By having the potential balance of the pitting potential as described above, it is possible to increase the corrosion resistance of the brazing sheet 1 and prevent the formation of through holes.

＜ブレージングシートの製造＞
前述の構成のブレージングシート１を製造するには、例えば、溶解鋳造により得られる本発明の組成範囲内である芯材用アルミニウム合金鋳塊、犠牲材用アルミニウム合金鋳塊およびろう材用アルミニウム合金鋳塊を用意する。
これらのアルミニウム合金の鋳塊は、例えば、５３０〜６００℃で８〜１６時間加熱する均質化処理を行なうことができる。該鋳塊は熱間圧延を経て合金板とされる。また連続鋳造圧延を経て合金板とするものであってもよい。
これらのアルミニウム合金板は、通常はクラッドに組み付けられて適宜のクラッド率でクラッドされる。クラッドは、一般に圧延により行われる。その後、さらに冷間圧延を行なうことで所望の厚さのアルミニウム合金ブレージングシートが得られる。クラッド材の構成は、例えば、犠牲材：芯材：ろう材＝１５％：７５％：１０％とすることができる。ただし、上記クラッド材の構成はこれに限定されるものではなく、例えば、犠牲材のクラッド率を１７％や２０％にしてもよい。
上記製造工程では、冷間圧延に際し中間焼鈍を介在させることができる。該中間焼鈍は、例えば２００〜４００℃で１〜６時間程度の加熱によって行なうことができる。中間焼鈍後の最終圧延では、１０〜５０％の冷間圧延率で圧延を行なう。作製されたクラッド材は高純度窒素ガス雰囲気中でドロップ形式により、ろう付け相当熱処理を行なう。ろう付け相当熱処理は例えば、室温から目標温度までの到達時間が１〜１５分となるような昇温速度で加熱し、５９０℃〜６１０℃の目標温度で１〜８分保持することにより行うことができる。 <Manufacture of brazing sheet>
In order to manufacture the brazing sheet 1 having the above-described configuration, for example, an aluminum alloy ingot for a core material, an aluminum alloy ingot for a sacrificial material, and an aluminum alloy cast for a brazing material that are within the composition range of the present invention obtained by melt casting. Prepare a lump.
These aluminum alloy ingots can be subjected to a homogenization treatment, for example, by heating at 530 to 600 ° C. for 8 to 16 hours. The ingot is hot rolled to be an alloy plate. Further, it may be an alloy plate through continuous casting and rolling.
These aluminum alloy plates are usually assembled into a clad and clad at an appropriate clad rate. The cladding is generally performed by rolling. Thereafter, cold rolling is performed to obtain an aluminum alloy brazing sheet having a desired thickness. The composition of the clad material can be, for example, sacrificial material: core material: brazing material = 15%: 75%: 10%. However, the configuration of the cladding material is not limited to this, and for example, the cladding rate of the sacrificial material may be 17% or 20%.
In the manufacturing process, intermediate annealing can be interposed during cold rolling. The intermediate annealing can be performed, for example, by heating at 200 to 400 ° C. for about 1 to 6 hours. In the final rolling after the intermediate annealing, rolling is performed at a cold rolling rate of 10 to 50%. The produced clad material is subjected to a brazing equivalent heat treatment by a drop method in a high purity nitrogen gas atmosphere. The brazing equivalent heat treatment is performed, for example, by heating at a rate of temperature rise from room temperature to a target temperature of 1 to 15 minutes and holding at a target temperature of 590 ° C. to 610 ° C. for 1 to 8 minutes. Can do.

以上構成のブレージングシート１において、ＭｎとＳｉを含み、Ｃｕの含有量を特定の範囲として芯材１ａを薄肉化に対応した高強度材としながら、犠牲材１ｃについてもＺｎ、Ｍｎ、Ｓｉを特定の範囲として犠牲材１ｃを薄肉化に対応した高強度材とした上に、芯材と犠牲材との関係で芯材の孔食電位バランスを特定の関係とすることで薄肉化に対応しても耐食性に優れたブレージングシートを提供できる。
このため、前述のブレージングシートを用いて熱交換器を構成すると薄型で軽量であり耐食性に優れた熱交換器を提供できる。
前述の構成において、図４に示すような電位バランスにできるのは、ろう付熱処理条件の適正化による。具体的にはろう付熱処理時の昇温および冷却を従来よりも短い時間で実施することにより、材料に負荷される入熱を抑え、元素の拡散を抑制することが可能となり、図４に示すような規定の電位バランスを実現することができる。 In the brazing sheet 1 configured as described above, Zn, Mn, and Si are also specified for the sacrificial material 1c while containing the Mn and Si and making the core material 1a a high strength material corresponding to thinning with a specific range of Cu. In addition to making the sacrificial material 1c a high-strength material corresponding to thinning as a range, the pitting corrosion potential balance of the core material in a specific relationship between the core material and the sacrificial material corresponds to the thinning. Can provide a brazing sheet having excellent corrosion resistance.
For this reason, if a heat exchanger is comprised using the above-mentioned brazing sheet, the heat exchanger which is thin and lightweight and excellent in corrosion resistance can be provided.
In the above configuration, the potential balance as shown in FIG. 4 can be achieved by optimizing the brazing heat treatment conditions. Specifically, by performing heating and cooling during brazing heat treatment in a shorter time than conventional, it is possible to suppress heat input to the material and suppress element diffusion, as shown in FIG. Such a prescribed potential balance can be realized.

以下、実施例を示して本発明をさらに詳細に説明するが、本発明はこれらの実施例に限定されるものではない。
＜供試材の作製＞
半連続鋳造により芯材用アルミニウム合金、犠牲材用アルミニウム合金、及びろう材用アルミニウム合金を鋳造した。なお、芯材用アルミニウム合金の組成と供試材Ｎｏ.を表１に示し、犠牲材用アルミニウム合金の組成と供試材Ｎｏ.を表２に示し、ろう材用アルミニウム合金の組成を表３に示す。 EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated further in detail, this invention is not limited to these Examples.
<Production of test material>
Aluminum alloy for core material, aluminum alloy for sacrificial material, and aluminum alloy for brazing material were cast by semi-continuous casting. The composition of the aluminum alloy for the core material and the test material No. are shown in Table 1, the composition of the aluminum alloy for the sacrificial material and the test material No. are shown in Table 2, and the composition of the aluminum alloy for the brazing material is shown in Table 3. Shown in

得られた芯材は５８０℃で８ｈｒの均質化処理を行なった。この均質化処理の条件は一例であり、温度：５３０〜６００℃、保持時間：８〜１６時間の範囲から選択することができる。また、犠牲材及びろう材は均質化処理を行わなかった。 The obtained core material was homogenized at 580 ° C. for 8 hours. The conditions for this homogenization treatment are examples, and can be selected from the range of temperature: 530 to 600 ° C. and holding time: 8 to 16 hours. Further, the sacrificial material and the brazing material were not subjected to homogenization treatment.

次に、芯材の一方の面に犠牲材を、さらに他方の面にろう材を組み合わせて熱間圧延してクラッド材とし、さらに冷間圧延を行った。その後、中間焼鈍を３３０℃で４時間行い、所定の圧延率とした最終の冷間圧延により厚さ０．１８ｍｍのＨ１４調質のクラッド材（供試材）を作製した。クラッド材の構成は、犠牲材：芯材：ろう材（厚さ）＝１５％：７５％：１０％とした。このクラッド材においてろう付け相当熱処理前の芯材の材料板厚は１３５μｍ、ろう材の厚さは１８μｍ、犠牲材の厚さは２７μｍである。ただし、中間焼鈍は、温度：２００〜３８０℃、保持時間：１〜６時間の範囲から選択することができる。 Next, a sacrificial material was combined on one surface of the core material, and a brazing material was combined on the other surface, which was hot-rolled to form a clad material, and further cold-rolled. Thereafter, intermediate annealing was performed at 330 ° C. for 4 hours, and a cold-rolled H14 tempered clad material (test material) having a thickness of 0.18 mm was produced by final cold rolling at a predetermined rolling rate. The composition of the clad material was sacrificial material: core material: brazing material (thickness) = 15%: 75%: 10%. In this clad material, the thickness of the core material before brazing equivalent heat treatment is 135 μm, the thickness of the brazing material is 18 μm, and the thickness of the sacrificial material is 27 μm. However, the intermediate annealing can be selected from the range of temperature: 200 to 380 ° C. and holding time: 1 to 6 hours.

このクラッド材について、室温から４００℃の到達時間が１分３０秒〜２分３０秒、４００℃〜５５０℃の到達時間が３０秒〜1分３０秒、５５０〜目標温度までの到達時間が３０秒〜1分３０秒となるような昇温速度で加熱し、６００℃の目標温度で1分間保持し、その後、３００℃まで約１００℃/ｍｉｎで冷却した後、室温まで空冷を行なうろう付け相当熱処理を施した。この時、ろう付時間：ｔ、Ｚｎの拡散係数：Ｄとした場合に√ΣＤｔにより与えられる入熱量は１３〜２３となる。この熱処理によりろう材はろう付け時相当の熱を受けて溶融するとともに犠牲層から元素拡散がなされて芯材側にＺｎを主体とする元素が拡散される。 For this clad material, the arrival time from room temperature to 400 ° C. is 1 minute 30 seconds to 2 minutes 30 seconds, the arrival time 400 ° C. to 550 ° C. is 30 seconds to 1 minute 30 seconds, and the arrival time 30 to 550 to the target temperature is 30 Brazing is performed at a heating rate of 1 second to 30 minutes, held at a target temperature of 600 ° C. for 1 minute, then cooled to 300 ° C. at about 100 ° C./min, and then air-cooled to room temperature. Appropriate heat treatment was applied. At this time, when the brazing time is t and the diffusion coefficient of Zn is D, the heat input given by √ΣDt is 13-23. By this heat treatment, the brazing material is melted by receiving a considerable amount of heat at the time of brazing, and element diffusion is performed from the sacrificial layer, so that an element mainly composed of Zn is diffused to the core material side.

以上の工程を経て、サンプルＮｏ.１〜Ｎｏ.２２のブレージングシートを作製した。以下の表４にサンプルＮｏ.１〜Ｎｏ.２２のブレージングシートの芯材種別、犠牲材種別、ろう材種別を示す。なお、表１〜表３において、表記された元素の残部は、Ａｌ及び不可避不純物である。また、各供試材について、内部耐食性と外部耐食性と成形性を評価した結果を以下の表４にまとめて示す。 The brazing sheet of sample No.1-No.22 was produced through the above process. Table 4 below shows the core material type, sacrificial material type, and brazing material type of the brazing sheets of Samples No. 1 to No. 22. In Tables 1 to 3, the balance of the elements described is Al and inevitable impurities. Further, the results of evaluating the internal corrosion resistance, the external corrosion resistance, and the moldability of each test material are summarized in Table 4 below.

「内部耐食性」
ろう付け相当熱処理後の供試材から３０×５０ｍｍのサンプルを切り出し、犠牲材側について、Ｃｌ⁻：１９５ｐｐｍ、ＳＯ_４ ^２−：６０ｐｐｍ、Ｃｕ^２＋：１ｐｐｍ、Ｆｅ^３+：３０ｐｐｍを含む水溶液中で８０℃×８時間→室温×１６時間のサイクルで浸漬試験を８週間実施した。腐食試験後のサンプルを沸騰させたリン酸クロム酸混合溶液に浸漬して腐食生成物を除去した後、最大腐食部の断面観察を実施して腐食深さを測定した結果を内部耐食性とする。腐食深さが３５μｍ以下であったものを◎と評価し、３５μｍ超、５０μｍ以下のものを○と評価し、５０μｍ超、９０μｍ以下のものを△と評価し、９０μｍ超のものを×と評価した。 "Internal corrosion resistance"
A 30 × 50 mm sample was cut out from the test material after brazing equivalent heat treatment, and in the aqueous solution containing Cl ⁻ : 195 ppm, SO ₄ ²⁻ : 60 ppm, Cu ²⁺ : 1 ppm, Fe ³⁺ : 30 ppm on the sacrificial material side. The immersion test was carried out for 8 weeks in a cycle of 80 ° C. × 8 hours → room temperature × 16 hours. After removing the corrosion product by immersing the sample after the corrosion test in a boiling phosphoric acid chromic acid mixed solution, the cross-sectional observation of the maximum corrosion portion is performed, and the result of measuring the corrosion depth is defined as internal corrosion resistance. When the corrosion depth is 35 μm or less, it is evaluated as ◎, when it is more than 35 μm or less than 50 μm, it is evaluated as ○, when it is more than 50 μm or less than 90 μm, it is evaluated as Δ, and when it is more than 90 μm, it is evaluated as ×. did.

「外部耐食性」
外部耐食性とは、ろう付け相当熱処理後の供試材から３０×１００ｍｍのサンプルを切り出し、ろう材側について、ＡＳＴＭＧ８５−Ａ３で規定されているＳＷＡＡＴ試験を５００時間実施した。腐食試験後のサンプルを沸騰させたリン酸クロム酸混合溶液に浸漬して腐食生成物を除去した後、最大腐食部の断面観察を実施して腐食深さを測定した結果を外部耐食性とする。腐食深さが３５μｍ以下であったものを◎と評価し、３５μｍ超、５０μｍ以下のものを○と評価し、５０μｍ超、９０μｍ以下のものを△と評価し、９０μｍ超のものを×と評価した。
「成形性」
ろう付け相当熱処理前の供試材を犠牲材が内側となるようにして、Ｂ型チューブ形状に加工した。加工したチューブの断面を樹脂に埋め込んで、光学顕微鏡で内柱の形状を観察し、目的とした形状（寸法）からのずれを測定した。目的とした寸法からのずれが１０μｍ以下であったものを◎と評価し、１０μｍ超、１５μｍ以下であったものを○と評価し、１５μｍ超、２０μｍ以下であったものを△と評価し、２０μｍ超であったものを×と評価した。 "External corrosion resistance"
With regard to external corrosion resistance, a sample of 30 × 100 mm was cut out from a specimen after heat treatment corresponding to brazing, and the SWAAT test defined by ASTM G85-A3 was performed for 500 hours on the brazing material side. After removing the corrosion product by immersing the sample after the corrosion test in a boiling phosphoric acid chromic acid mixed solution, the cross-sectional observation of the maximum corrosion portion is performed and the corrosion depth is measured, and the external corrosion resistance is obtained. When the corrosion depth is 35 μm or less, it is evaluated as ◎, when it is more than 35 μm or less than 50 μm, it is evaluated as ○, when it is more than 50 μm or less than 90 μm, it is evaluated as Δ, and when it is more than 90 μm, it is evaluated as ×. did.
"Formability"
The specimen before brazing equivalent heat treatment was processed into a B-shaped tube shape with the sacrificial material inside. The cross section of the processed tube was embedded in resin, the shape of the inner pillar was observed with an optical microscope, and the deviation from the intended shape (dimension) was measured. When the deviation from the intended dimension is 10 μm or less, it is evaluated as ◎, when it is more than 10 μm and 15 μm or less, it is evaluated as ◯, and when it is more than 15 μm and 20 μm or less, it is evaluated as Δ. What was more than 20 micrometers was evaluated as x.

以下、表４に示すブレージングシートの各サンプルの特徴について説明する。
サンプルＮｏ．１〜１９は、ブレージングシートにおける厚さ方向の電位差バランスを本発明で目標とする範囲内に納めた供試材である。
即ち、ろう付熱処理後の孔食電位において、ブレージングシートの厚さ方向に沿って孔食電位を測定した場合、芯材の最も貴な電位との電位差を１００ｍＶ以上とする領域の厚さが、ブレージングシートの材料板厚の１０％〜５０％となっている。 Hereinafter, characteristics of each sample of the brazing sheet shown in Table 4 will be described.
Sample No. Reference numerals 1 to 19 are test materials in which the potential difference balance in the thickness direction of the brazing sheet is within the target range of the present invention.
That is, in the pitting potential after brazing heat treatment, when the pitting potential is measured along the thickness direction of the brazing sheet, the thickness of the region where the potential difference from the most noble potential of the core material is 100 mV or more is It is 10% to 50% of the material plate thickness of the brazing sheet.

また、芯材が質量％でＣｕ：０．５〜１．３％、Ｍｎ：０．５〜１．８％、Ｓｉ：０．０５〜１．３％、Ｆｅ：０．０５〜０．５％、Ｍｇ：０．０５〜０．５％、Ｚｒ：０．０５〜０．３％、Ｔｉ：０．０５〜０．３％、Ｃｒ：０．０５〜０．３％から選択される１種または２種以上をさらに含有するＡｌ−Ｍｎ−Ｓｉ系アルミニウム合金からなり、犠牲材が質量％でＺｎ：４．０〜７．０％、Ｍｎ：１．０〜１．８％、Ｓｉ：０．２〜１．２％含有し、残部がＡｌおよび不可避不純物からなるアルミニウム合金からなり、ろう材が質量％でＳｉ：６．０〜１１．０％、Ｚｎ：０．１〜３．０％含有し、残部がＡｌおよび不可避不純物からなるアルミニウム合金からなる。
また、ろう付相当熱処理後の孔食電位において、芯材の最も貴な電位との電位差を１００ｍＶ以上とする領域の中で、犠牲材最表面から芯材の板厚方向に向かった領域の長さをＡμｍ、ろう材最表面から芯材の板厚方向に向かった領域の長さをＢμｍとした時、１＜（Ａ＋１）／（Ｂ＋１）＜６１の関係が維持されている。
また、ろう付け相当熱処理後の芯材と犠牲材の孔食電位差が１６０〜２９０ｍＶの範囲にされている。
また、ろう付相当熱処理後のブレージングシートにおいてＺｎ濃度０．２％以下の領域が、ブレージングシートの材料板厚の２０％〜７０％の範囲とされている。
これらの電位バランスを満たしているブレージングシートは、例えば、図４に示す上に凸型の曲線を有する電位バランスであり、凸型の曲線の両端側の孔食電位がいずれも急激に低下する曲線となっている。 Further, when the core material is mass%, Cu: 0.5 to 1.3%, Mn: 0.5 to 1.8%, Si: 0.05 to 1.3%, Fe: 0.05 to 0.5 %, Mg: 0.05 to 0.5%, Zr: 0.05 to 0.3%, Ti: 0.05 to 0.3%, Cr: 0.05 to 0.3% 1 It consists of an Al-Mn-Si-based aluminum alloy further containing seeds or two or more kinds, and the sacrificial material is Zn: 4.0-7.0%, Mn: 1.0-1.8%, Si: It is comprised of 0.2 to 1.2%, the balance is made of an aluminum alloy composed of Al and inevitable impurities, and the brazing filler metal is mass%, Si: 6.0 to 11.0%, Zn: 0.1 to 3.0 %, And the balance is made of an aluminum alloy composed of Al and inevitable impurities.
Further, in the pitting corrosion potential after brazing equivalent heat treatment, the length of the region from the outermost surface of the sacrificial material toward the thickness direction of the core material in the region where the potential difference from the most noble potential of the core material is 100 mV or more. The relationship of 1 <(A + 1) / (B + 1) <61 is maintained when the thickness is A μm and the length of the region from the outermost surface of the brazing material in the thickness direction of the core material is B μm.
The pitting corrosion potential difference between the core material and the sacrificial material after brazing equivalent heat treatment is in the range of 160 to 290 mV.
In the brazing sheet after brazing-corresponding heat treatment, the region with a Zn concentration of 0.2% or less is in the range of 20% to 70% of the material plate thickness of the brazing sheet.
The brazing sheet satisfying these potential balances is, for example, a potential balance having a convex curve on the top as shown in FIG. 4, and a curve in which the pitting corrosion potentials at both ends of the convex curve rapidly decrease. It has become.

Ｎｏ.１４の供試材は芯材との電位差１００μｍ以上の領域の長さのみ望ましい範囲（１６〜９０μｍ）より若干小さな例であるが、内部耐食性が若干低下するものの、外部耐食性は良好であり、成形性は優れていた。
Ｎｏ.１５の供試材はＡ＋１／Ｂ＋１の値が望ましい範囲（１〜６１）より若干小さいため、内部耐食性が若干低下する傾向になるものの、外部耐食性と成型性は良好であった。
Ｎｏ.１６の供試材は、芯材と犠牲材の孔食電位差が望ましい範囲（１６０〜２９０ｍＶ）より若干小さい例であるが、内部耐食性と外部耐食性が良好であり、成形性は優れていた。
Ｎｏ.１７の供試材はＺｎ濃度０．２％以下の領域の長さが望ましい範囲（３６〜１６μｍ）より若干短いが、外部耐食性と成形性に優れ、内部耐食性も良好であった。
Ｎｏ.１８の試料は芯材との電位差１００μｍ以上の領域の長さのみ望ましい範囲であるが、Ａ＋１／Ｂ＋１の値は望ましい範囲より若干小さく、芯材と犠牲材の孔食電位差は望ましい範囲より若干小さく、Ｚｎ濃度０．２％以下の領域の長さが望ましい範囲より若干短いが、内部耐食性と外部耐食性において若干低下するものの成形性は良好であった。
Ｎｏ.１９の供試材は、芯材との電位差１００μｍ以上の領域の長さとＡ＋１／Ｂ＋１の値が望ましい範囲であるが、芯材と犠牲材の孔食電位差が望ましい範囲より若干小さく、Ｚｎ濃度０．２％以下の領域の長さが好ましい範囲より若干短いが、外部耐食性と成形性は良好であり、内部耐食性が若干低下する傾向であった。 The sample No. 14 is an example in which the length of the region having a potential difference of 100 μm or more from the core material is slightly smaller than the desired range (16 to 90 μm), but the external corrosion resistance is good although the internal corrosion resistance is slightly reduced. The moldability was excellent.
In the sample No. 15, the value of A + 1 / B + 1 was slightly smaller than the desired range (1 to 61), so that the internal corrosion resistance tended to be slightly lowered, but the external corrosion resistance and moldability were good.
The sample material of No. 16 is an example in which the pitting corrosion potential difference between the core material and the sacrificial material is slightly smaller than the desired range (160 to 290 mV), but the internal corrosion resistance and the external corrosion resistance are good, and the moldability is excellent. .
In the sample No. 17, the length of the Zn concentration of 0.2% or less was slightly shorter than the desired range (36 to 16 μm), but the external corrosion resistance and formability were excellent, and the internal corrosion resistance was also good.
In the sample No. 18, only the length of the region having a potential difference of 100 μm or more from the core material is a desirable range, but the value of A + 1 / B + 1 is slightly smaller than the desirable range, and the pitting potential difference between the core material and the sacrificial material is smaller than the desirable range. Although slightly smaller and the length of the region having a Zn concentration of 0.2% or less is slightly shorter than the desired range, the moldability was good although the internal corrosion resistance and the external corrosion resistance were slightly decreased.
In the test material of No. 19, the length of the region having a potential difference of 100 μm or more from the core material and the value of A + 1 / B + 1 are desirable ranges, but the pitting potential difference between the core material and the sacrificial material is slightly smaller than the desirable range. Although the length of the region having a concentration of 0.2% or less was slightly shorter than the preferred range, the external corrosion resistance and moldability were good, and the internal corrosion resistance tended to be slightly lowered.

これらの供試材に対し、Ｎｏ.２０の供試材は、芯材のＭｎ含有量が望ましい範囲より低くなり過ぎ、犠牲材のＭｎ含有量が望ましい範囲より低くなり過ぎ、ろう材のＺｎ含有量が望ましい範囲より高くなり過ぎたため、外部耐食性に劣る結果となった。
Ｎｏ.２１の供試材は、芯材のＭｎ含有量が望ましい範囲より高くなり過ぎ、犠牲材のＭｎ含有量が望ましい範囲より高くなり過ぎ、ろう材のＺｎ含有量が望ましい範囲より低くなり過ぎたため、成形性に劣る結果となった。
Ｎｏ.２２の供試材は、芯材のＳｉ含有量が望ましい範囲より高くなり過ぎ、犠牲材のＳｉ含有量が望ましい範囲より低くなり過ぎ、ろう材のＳｉ含有量が望ましい範囲より高くなり過ぎたため、ろう付け相当熱処理時に芯材が溶融した。 In contrast to these test materials, the test material No. 20 has a Mn content of the core material that is too low than the desired range, a Mn content of the sacrificial material that is too low than the desired range, and a Zn content of the brazing material. The amount was too high above the desired range, resulting in poor external corrosion resistance.
In the test material of No. 21, the Mn content of the core material is too high than the desired range, the Mn content of the sacrificial material is too high than the desired range, and the Zn content of the brazing material is too low. Therefore, the result was inferior in moldability.
In the test material of No. 22, the Si content of the core material is too high than the desired range, the Si content of the sacrificial material is too low than the desired range, and the Si content of the brazing material is too high than the desired range. Therefore, the core material melted during the brazing equivalent heat treatment.

Ｎｏ.２３の供試材は、芯材のＦｅ含有量が望ましい範囲より高くなり過ぎ、犠牲材のＳｉ含有量が望ましい範囲より高くなり過ぎ、ろう材のＳｉ含有量が望ましい範囲より低くなり過ぎたため、ろう付け相当熱処理時に犠牲材が溶融した。
Ｎｏ.２４の供試材は、芯材のＭｇ含有量が望ましい範囲より高くなり過ぎ、犠牲材のＭｎ含有量が望ましい範囲より低くなり過ぎ、ろう材のＳｉ含有量が望ましい範囲より低くなり過ぎたため、成形性に劣る結果となった。
Ｎｏ.２５の供試材は、芯材のＺｒ、Ｔｉ、Ｃｒ含有量が望ましい範囲より高くなり過ぎ、犠牲材のＺｎ含有量が望ましい範囲より低くなり過ぎ、ろう材のＳｉ含有量が望ましい範囲より高くなり過ぎたため、内部耐食性に劣る結果となった。 In the specimen No. 23, the Fe content of the core material is too high than the desired range, the Si content of the sacrificial material is too high than the desired range, and the Si content of the brazing material is too low than the desired range. Therefore, the sacrificial material melted during the brazing equivalent heat treatment.
In the specimen No. 24, the Mg content of the core material is too high than the desired range, the Mn content of the sacrificial material is too low than the desired range, and the Si content of the brazing material is too low than the desired range. Therefore, the result was inferior in moldability.
The No. 25 specimen has a Zr, Ti, Cr content of the core material that is too high than the desired range, a Zn content of the sacrificial material that is too low than the desired range, and a Si content of the brazing material that is desirable. Since it became too high, it resulted in inferior internal corrosion resistance.

Ｎｏ.２６の供試材は、芯材のＣｕ含有量が望ましい範囲より低くなり過ぎ、犠牲材のＭｎ含有量が望ましい範囲より高くなり過ぎたため、内部耐食性と外部耐食性の両方で劣る結果となった。
Ｎｏ.２７の供試材は、芯材のＣｕ含有量が望ましい範囲より高くなり過ぎ、犠牲材のＭｎ含有量が望ましい範囲より低くなり過ぎたため、内部耐食性と外部耐食性の両方で劣る結果となった。
Ｎｏ.２８の供試材は、芯材の最も貴な電位との電位差を１００ｍＶ以上とする領域の厚さが、前記芯材の材料板厚の１０％〜５０％となる関係から外れて薄すぎたためと、Ｍｎ含有量が多すぎたため、内部耐食性と成形性に劣る結果となった。 The test material of No. 26 was inferior in both internal corrosion resistance and external corrosion resistance because the Cu content of the core material was too low than the desired range and the Mn content of the sacrificial material was too high than the desired range. It was.
The test material of No. 27 had a result that both the internal corrosion resistance and the external corrosion resistance were inferior because the Cu content of the core material was too higher than the desired range and the Mn content of the sacrificial material was too lower than the desired range. It was.
The specimen No. 28 is thin, because the thickness of the region in which the potential difference from the most noble potential of the core material is 100 mV or more is 10% to 50% of the material thickness of the core material. Since it was too much and Mn content was too much, it resulted in inferior to internal corrosion resistance and a moldability.

Ｎｏ.２９の供試材は、Ａ＋１／Ｂ＋１の値が望ましい範囲より若干小さく、Ｍｎ含有量が多すぎたため、内部耐食性と成形性に劣る結果となった。
Ｎｏ.３０の供試材は、ろう付熱処理後の前記芯材と前記犠牲材の孔食電位差が１６０〜２９０ｍＶの範囲内になく、小さすぎたためと、Ｍｎ含有量が多すぎたため、内部耐食性と成形性に劣る結果となった。
Ｎｏ.３１の供試材は、Ｚｎ濃度０．２％以下の領域の厚さが小さいため、内部耐食性と外部耐食性の両方に劣る結果となった。図７は、この供試材のようにＺｎ濃度０．２％以下の領域の一例を示すが、図６に示すようにＺｎ濃度０．２％以下の領域の厚さが芯材の材料板厚の２０〜７０％の範囲を占めることが好ましい。 In the sample No. 29, the value of A + 1 / B + 1 was slightly smaller than the desired range, and the Mn content was too high, resulting in poor internal corrosion resistance and moldability.
The No. 30 test material had a pitting corrosion potential difference between the core material after the brazing heat treatment and the sacrificial material in the range of 160 to 290 mV, and was too small, and because the Mn content was too large, internal corrosion resistance. As a result, the moldability was inferior.
Since the thickness of the area | region whose Zn density | concentration is 0.2% or less was small, the test material of No. 31 was inferior to both internal corrosion resistance and external corrosion resistance. FIG. 7 shows an example of a region having a Zn concentration of 0.2% or less as in this test material. As shown in FIG. 6, the thickness of the region having a Zn concentration of 0.2% or less is a core material plate. It is preferable to occupy a range of 20 to 70% of the thickness.

Ｎｏ.３２の供試材は、従来のブレージングシートであるが、芯材の最も貴な電位との電位差を１００ｍＶ以上とする領域の厚さが不足し、芯材と犠牲材の孔食電位差が１６０〜２９０ｍＶの範囲内になく、小さすぎ、Ｚｎ濃度０．２％以下の領域の厚さが小さいため、内部耐食性と外部腐食両方に劣る結果となった。
この供試材の孔食電位の分布を図５に示すが、図４に示す本発明に係る供試材の孔食電位の分布との違いが明らかである。
Ｎｏ.３３の供試材は、芯材のＣｕ含有量が少ない試料であり、Ｎｏ.３４の供試材は犠牲材のＺｎ含有量が少ない試料であるが、いずれの試料も内部耐食性が劣る結果となった。Ｎｏ.３５の供試材はろう材のＺｎ含有量が少ない試料であるが、外部耐食性に劣る結果となった。 The test material No. 32 is a conventional brazing sheet, but the thickness of the region where the potential difference from the most noble potential of the core material is 100 mV or more is insufficient, and the pitting potential difference between the core material and the sacrificial material is small. Since it was not in the range of 160 to 290 mV and was too small and the thickness of the Zn concentration of 0.2% or less was small, the results were inferior to both internal corrosion resistance and external corrosion.
The distribution of the pitting corrosion potential of this specimen is shown in FIG. 5, and the difference from the distribution of the pitting corrosion potential of the specimen according to the present invention shown in FIG. 4 is clear.
The sample material No. 33 is a sample with a low Cu content in the core material, and the sample material No. 34 is a sample with a low Zn content in the sacrificial material, but all the samples have poor internal corrosion resistance. As a result. The specimen No. 35 was a sample with a low Zn content in the brazing filler metal, but the result was inferior in external corrosion resistance.

１…ブレージングシート、１ａ…芯材、１ｂ…ろう材、１ｃ…犠牲材、１０…チューブ、２０…熱交換器、２１…ヘッダー、２２…アウターフィン、２３…サイドサポート。 DESCRIPTION OF SYMBOLS 1 ... Brazing sheet, 1a ... Core material, 1b ... Brazing material, 1c ... Sacrificial material, 10 ... Tube, 20 ... Heat exchanger, 21 ... Header, 22 ... Outer fin, 23 ... Side support.

Claims

An aluminum alloy brazing sheet in which a sacrificial material is clad on one surface of a core material and a brazing material is clad on the other surface, wherein the core material contains Cu: 0.5 to 1.3% by mass%. It consists of a Mn-Si based aluminum alloy, and the sacrificial material contains Zn: 4.0-7.0%, Mn: 1.0-1.8%, Si: 0.2-1.2% by mass. The balance is made of an aluminum alloy composed of Al and inevitable impurities, and the brazing filler material contains Si: 6.0 to 11.0% and Zn: 0.1 to 3.0% by mass, and the balance is Al and inevitable. Made of an aluminum alloy made of impurities,
In the pitting corrosion potential after the brazing heat treatment, when the pitting corrosion potential is measured along the thickness direction of the brazing sheet, the thickness of the region where the potential difference from the most noble potential of the core material is 100 mV or more is An aluminum alloy brazing sheet having a thickness of 0.18 mm or less, characterized in that the thickness is 10% to 50% of the material thickness of the brazing sheet.

Further, the core material is further Mn: 0.5 to 1.8%, Si: 0.05 to 1.3%, Fe: 0.05 to 0.5%, Mg: 0.05 to 0. Aluminum further containing one or more selected from 5%, Zr: 0.05 to 0.3%, Ti: 0.05 to 0.3%, Cr: 0.05 to 0.3% The aluminum alloy brazing sheet according to claim 1 made of an alloy.

In the pitting corrosion potential after brazing heat treatment, the length of the region from the outermost surface of the sacrificial material toward the plate thickness direction in the region where the potential difference from the most noble potential of the core material is 100 mV or more The relationship of 1 <(A + 1) / (B + 1) <61 is satisfied, where A is μm and the length of the region from the outermost surface of the brazing material toward the thickness direction of the core material is B μm. The aluminum alloy brazing sheet described in 1.

The aluminum alloy brazing sheet according to any one of claims 1 to 3, wherein a pitting corrosion potential difference between the core material and the sacrificial material after brazing heat treatment is in a range of 160 to 290 mV.

The aluminum region according to any one of claims 1 to 4, wherein a region having a Zn concentration of 0.2% or less after brazing heat treatment is 20% to 70% of a material plate thickness of the brazing sheet. Alloy brazing sheet.