JP5702982B2

JP5702982B2 - Aluminum alloy clad material

Info

Publication number: JP5702982B2
Application number: JP2010228265A
Authority: JP
Inventors: 路英吉野; 黒田　周; 周黒田
Original assignee: Mitsubishi Aluminum Co Ltd
Current assignee: MA Aluminum Corp
Priority date: 2010-10-08
Filing date: 2010-10-08
Publication date: 2015-04-15
Anticipated expiration: 2030-10-08
Also published as: JP2012082459A

Description

本発明は、自動車熱交換器用チューブ材等に用いられるアルミニウム合金クラッド材に係り、なかでも電縫溶接チューブ用に好適なブレージングシート（クラッド材）に関する。 The present invention relates to an aluminum alloy clad material used for an automotive heat exchanger tube material and the like, and more particularly to a brazing sheet (clad material) suitable for an electric resistance welded tube.

近年、自動車のラジエータなどの熱交換器には軽量化、高性能化が求められている。このようなトレンドに対して、チューブなどの構成部材の薄肉化が要求されているが、そのためにはチューブ材の高強度化が必要である。
このような要求に対応したものとして、特許文献１に開示の熱交換器用アルミニウム合金ブレージングシートがある。このブレージングシートは、電縫溶接によりチューブ状に形成されるものであり、芯材と、この芯材の一面側に形成された犠牲材と、この芯材の他面側に形成されたＡｌ合金からなるろう材とを備えている。犠牲材に、多量のＳｉ、Ｍｇを添加することにより、ろう付後強度を向上させるとともに、ろう付前の犠牲材の硬度をろう材の硬度よりも所定以上高くすることで、薄肉化したチューブ材においても、チューブ材自体の耐座屈性を確保している。 In recent years, heat exchangers such as automobile radiators are required to be lighter and higher performance. In response to such a trend, it is required to reduce the thickness of structural members such as tubes. To that end, it is necessary to increase the strength of the tube material.
In response to such a requirement, there is an aluminum alloy brazing sheet for a heat exchanger disclosed in Patent Document 1. This brazing sheet is formed into a tube shape by electro-welding, and includes a core material, a sacrificial material formed on one surface side of the core material, and an Al alloy formed on the other surface side of the core material. And brazing material. By adding a large amount of Si and Mg to the sacrificial material, the strength after brazing is improved, and the thickness of the sacrificial material before brazing is set to be higher than the hardness of the brazing material by a predetermined level, thereby reducing the thickness of the tube. Also in the material, the buckling resistance of the tube material itself is secured.

特開２０１０−１０６３４５号公報JP 2010-106345 A

しかしながら、特許文献１記載のブレージングシート（クラッド材）では、犠牲材のＭｇ量、Ｓｉ量が高いため、ろう付後の強度には優れるが、板厚が薄い場合にはろう付時に犠牲材に添加したＭｇがろう材側まで拡散して、フラックスと反応して、酸化皮膜の除去に有効なフラックス量が不足してしまうためろう付性が低下してしまうという問題がある。また、犠牲材のＳｉ量が多すぎることで、犠牲材の融点が低下してろう付時に犠牲材が溶融してしまうという問題もある。さらに、犠牲材のＳｉ量が高い場合、ろう付直後の強度は高くなるが、時効硬化性はむしろ低下してしまい、ラジエータ使用中（１００℃程度の高温に晒されるため時効硬化する）の強度向上が阻害されてしまう。
このように、特許文献１記載の従来材ではろう付性や融点などを満足しつつ、高強度を得ることが困難であった。 However, the brazing sheet (cladding material) described in Patent Document 1 is excellent in strength after brazing because the amount of Mg and Si in the sacrificial material is high, but if the plate thickness is thin, it becomes a sacrificial material during brazing. The added Mg diffuses to the brazing material side, reacts with the flux, and there is a problem that the brazing property is lowered because the amount of flux effective for removing the oxide film is insufficient. Moreover, since there is too much Si amount of a sacrificial material, there also exists a problem that melting | fusing point of a sacrificial material falls and a sacrificial material will fuse | melt at the time of brazing. Furthermore, when the amount of Si in the sacrificial material is high, the strength immediately after brazing is increased, but the age-hardening property is rather lowered, and the strength during use of the radiator (age hardening because it is exposed to a high temperature of about 100 ° C.). Improvement will be hindered.
Thus, with the conventional material described in Patent Document 1, it was difficult to obtain high strength while satisfying brazing properties and melting points.

本発明はこのような背景に鑑みてなされたものであり、ろう付性や融点などを満足しつつ高強度なアルミニウム合金クラッド材を提供することを目的とする。 This invention is made | formed in view of such a background, and it aims at providing the high intensity | strength aluminum alloy clad material satisfying brazing property, melting | fusing point, etc.

本発明のアルミニウム合金クラッド材は、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クラッド材であって、前記犠牲材は、Ｚｎ：４．１〜７．５質量％、Ｍｇ：１．２〜２．５質量％、Ｓｉ：０．１〜０．４質量％を含有し、残部がＡｌ及び不可避的不純物からなり、かつ、前記芯材は、Ｍｎ：１．０〜１．８質量％、Ｓｉ：０．５〜１．２質量％、Ｆｅ：０．１〜０．４質量％、Ｃｕ：０．５〜１．５質量％を含有し、残部がＡｌ及び不可避的不純物からなり、さらに、前記芯材のろう付後の平均結晶粒径が３０〜２００μｍの範囲にあり、前記犠牲材のＭｇ添加量に対してＺｎ添加量をＺｎ／Ｍｇ≧３とすることを特徴とする。 The aluminum alloy clad material of the present invention is an aluminum alloy clad material 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 sacrificial material contains Zn: 4.1-7. 5% by mass, Mg: 1.2-2.5% by mass, Si: 0.1-0.4% by mass, the balance is made of Al and inevitable impurities, and the core material is Mn: 1.0 to 1.8% by mass, Si: 0.5 to 1.2% by mass, Fe: 0.1 to 0.4% by mass, Cu: 0.5 to 1.5% by mass, the balance There of Al and unavoidable impurities, further, the average crystal grain size after brazing of said core material Ri range near the 30 to 200 [mu] m, the Zn addition amount with respect to Mg addition amount of the sacrificial material Zn / Mg It is characterized by ≧ 3 .

犠牲材のＭｇ量を１．２〜２．５質量％として、特許文献１記載のクラッド材のＭｇ量よりも低くすることでろう付性を確保した。
また、犠牲材のＳｉ量を０．１〜０．４質量％と低くすることで融点の向上を図って、ろう付時に犠牲材が局部溶融するのを阻止するとともに時効硬化性を向上させた。
一方、犠牲材のＭｇ量、Ｓｉ量を特許文献１記載のクラッド材よりも少なくしたことで、ろう付直後の強度が不足する懸念がある。これを補うため、Ｚｎ量を多くしているとともに、芯材の結晶粒径を微細とすることで結晶粒界を介した犠牲材から芯材へのＭｇ拡散を促進させ、ろう付後に芯材に供給されるＭｇ量を増加させることで強度および時効硬化性を向上させた。
また、Ｚｎ量が多いことから耐食性にも優れている。 Brazing properties were ensured by setting the Mg amount of the sacrificial material to 1.2 to 2.5 mass% and lower than the Mg amount of the clad material described in Patent Document 1.
In addition, the melting point was improved by lowering the Si content of the sacrificial material to 0.1 to 0.4% by mass, preventing the sacrificial material from locally melting during brazing and improving age hardening. .
On the other hand, there is a concern that the strength immediately after brazing is insufficient because the amount of Mg and Si in the sacrificial material is less than that of the clad material described in Patent Document 1. In order to compensate for this, the Zn content is increased and the crystal grain size of the core material is made fine to promote Mg diffusion from the sacrificial material to the core material via the crystal grain boundary. The strength and age-hardening properties were improved by increasing the amount of Mg supplied to.
Moreover, since there is much Zn amount, it is excellent also in corrosion resistance.

この場合、犠牲材のＺｎ添加量の前述した増加とともに、Ｍｇ添加量に対してＺｎ添加量をＺｎ／Ｍｇ≧３とすることにより、ろう付後の室温時効硬化性が高まり、ろう付後すぐから高強度が得られるようにした。 In this case, with the increase in the Zn addition amount of the sacrificial material as described above, by setting the Zn addition amount to Zn / Mg ≧ 3 with respect to the Mg addition amount, the room temperature age hardenability after brazing is improved, and immediately after brazing. High strength was obtained.

本発明によれば、ろう付性が良好で、犠牲材の融点を満足しつつろう付直後の強度が高く、かつ時効硬化性に優れ、熱交換器として使用中にも高強度が得られるブレージングシートを得ることができる。 According to the present invention, brazing with good brazing properties, high strength immediately after brazing while satisfying the melting point of the sacrificial material, excellent age-hardening properties, and high strength even during use as a heat exchanger. A sheet can be obtained.

本発明に係るアルミニウム合金クラッド材の縦断面図である。It is a longitudinal cross-sectional view of the aluminum alloy clad material which concerns on this invention. アルミニウム合金クラッド材におけるろう侵食深さを示す断面写真である。It is a cross-sectional photograph which shows the brazing erosion depth in an aluminum alloy clad material.

以下、本発明に係るアルミニウム合金クラッド材の実施形態を図面を参照しながら説明する。
このアルミニウム合金クラッド材１は、自動車熱交換器用チューブ材として用いられるもので、Ｍｎ：１．０〜１．８質量％、Ｓｉ：０．５〜１．２質量％、Ｆｅ：０．１〜０．４質量％、Ｃｕ：０．５〜１．５質量％を含有し、残部がＡｌ及び不可避的不純物からなる芯材２と、この芯材２の一方の面にクラッドされ、Ｚｎ：４．１〜７．５質量％、Ｍｇ：１．２〜２．５質量％、Ｓｉ：０．１〜０．４質量％を含有し、残部がＡｌ及び不可避的不純物からなる犠牲材３と、芯材２の他方の面にクラッドされたろう材４とから構成され、電縫溶接によりチューブ状に形成される。
芯材２、犠牲材３、ろう材４のそれぞれの成分組成の限定理由は以下の通りである。 Hereinafter, an embodiment of an aluminum alloy clad material according to the present invention will be described with reference to the drawings.
This aluminum alloy clad material 1 is used as a tube material for an automobile heat exchanger, Mn: 1.0 to 1.8% by mass, Si: 0.5 to 1.2% by mass, Fe: 0.1 to 0.1% 0.4% by mass, Cu: 0.5 to 1.5% by mass, the remainder being clad on one surface of the core material 2 made of Al and inevitable impurities, and Zn: 4 A sacrificial material 3 containing 1 to 7.5% by mass, Mg: 1.2 to 2.5% by mass, Si: 0.1 to 0.4% by mass, the balance being Al and inevitable impurities; It is comprised from the brazing | wax material 4 clad by the other surface of the core material 2, and is formed in a tube shape by electro-resistance welding.
The reasons for limiting the component composition of the core material 2, the sacrificial material 3, and the brazing material 4 are as follows.

＜芯材＞
（Ｍｎ）
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、材料の強度を高める効果がある。しかし、その添加量が下限未満ではその効果が十分発揮されず、上限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してしまう。このため、Ｍｎの含有量は１．０〜１．８質量％とする。より好ましくは１．１〜１．８質量％であり、さらに好ましくは１．２〜１．７質量％である。 <Core>
(Mn)
Mn has the effect of forming Al—Mn—Si, Al—Mn—Fe, and Al—Mn—Fe—Si intermetallic compounds in the matrix and increasing the strength of the material. However, if the addition amount is less than the lower limit, the effect is not sufficiently exerted. If the addition amount exceeds the upper limit, a huge intermetallic compound is generated at the time of casting, so that the formability of the material is lowered. For this reason, content of Mn shall be 1.0-1.8 mass%. More preferably, it is 1.1-1.8 mass%, More preferably, it is 1.2-1.7 mass%.

（Ｓｉ）
Ｓｉは、ろう付時に犠牲材から拡散したＭｇと微細なＭｇ−Ｓｉ化合物を形成することで強度を高める効果や、時効硬化性（熱交換器使用時に強度が上昇しやすい性質）を高める効果がある。また、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、材料の強度を高める効果がある。しかし、その添加量が下限未満ではその効果が十分発揮されず、上限を超えると材料の融点が低下してしまう。このため、Ｓｉの含有量は０．５〜１．２質量％とする。より好ましくは０．５〜１．１質量％であり、さらに好ましくは０．６〜１．１質量％である。 (Si)
Si has the effect of increasing strength by forming a fine Mg-Si compound with Mg diffused from the sacrificial material during brazing, and the effect of increasing age-hardening properties (property of increasing strength when using a heat exchanger). is there. In addition, there is an effect that the Al—Mn—Si-based and Al—Mn—Fe—Si-based intermetallic compounds are finely formed in the matrix to increase the strength of the material. However, if the addition amount is less than the lower limit, the effect is not sufficiently exhibited. If the addition amount exceeds the upper limit, the melting point of the material is lowered. For this reason, content of Si shall be 0.5-1.2 mass%. More preferably, it is 0.5-1.1 mass%, More preferably, it is 0.6-1.1 mass%.

（Ｆｅ）
Ｆｅは、マトリックス中に粗大なＡｌ−Ｍｎ−Ｆｅ系、Ａｌ−Ｍｎ−Ｆｅ−Ｓｉ系金属間化合物を形成して、ろう付熱処理後の結晶粒径を小さくすることにより、ろう付時の犠牲材から芯材へのＭｇ拡散を促進させることで強度を高める効果がある。しかし、その添加量が下限未満ではその効果が十分発揮されず、上限を超えると耐食性が低下してしまう。このため、Ｆｅの含有量は０．１〜０．４質量％とする。より好ましくは０．１５〜０．４質量％であり、さらに好ましくは０．２〜０．３８質量％である。 (Fe)
Fe is sacrificed during brazing by forming coarse Al—Mn—Fe and Al—Mn—Fe—Si intermetallic compounds in the matrix and reducing the crystal grain size after brazing heat treatment. There is an effect of increasing strength by promoting Mg diffusion from the material to the core material. However, if the addition amount is less than the lower limit, the effect is not sufficiently exhibited, and if the addition amount exceeds the upper limit, the corrosion resistance is lowered. For this reason, content of Fe shall be 0.1-0.4 mass%. More preferably, it is 0.15-0.4 mass%, More preferably, it is 0.2-0.38 mass%.

（Ｃｕ）
Ｃｕは、マトリックス中に固溶し、材料の強度を高める効果や、芯材に添加した場合、芯材の電位を貴として犠牲材との電位差が大きくなるため耐食性を向上させる効果がある。しかし、その添加量が下限未満ではその効果が十分発揮されず、上限を超えると材料の融点が低下してしまう。このため、Ｃｕの含有量は０．５〜１．５質量％とする。より好ましくは０．６〜１．２質量％であり、さらに好ましくは０．７〜１．１質量％である。 (Cu)
Cu is dissolved in the matrix to increase the strength of the material, and when added to the core material, Cu has the effect of improving the corrosion resistance because the potential of the core material is noble and the potential difference from the sacrificial material is increased. However, if the addition amount is less than the lower limit, the effect is not sufficiently exhibited. If the addition amount exceeds the upper limit, the melting point of the material is lowered. For this reason, content of Cu shall be 0.5-1.5 mass%. More preferably, it is 0.6-1.2 mass%, More preferably, it is 0.7-1.1 mass%.

＜犠牲材＞
（Ｚｎ）
Ｚｎは、ろう付後のごく短時間のうちにＭｇと微細なＭｇ−Ｚｎ化合物を形成してろう付後の強度を高める効果がある。また、電位を卑にするため犠牲材に添加した場合、芯材との電位差が大きくなり、ブレージングシートの耐食性を向上させる効果（腐食深さを低減する効果）がある。しかし、その添加量が下限未満ではその効果が十分発揮されず、上限を超えると融点が低下したり、また、腐食速度が速くなりすぎて犠牲材層が早期に消失する結果、腐食深さが増加してしまう（耐孔食性が低下してしまう）。このため、Ｚｎの含有量は４．１〜７．５質量％とする。より好ましくは４．５〜７．０質量％であり、さらに好ましくは４．８〜６．８質量％である。 <Sacrificial material>
(Zn)
Zn has the effect of increasing the strength after brazing by forming a fine Mg—Zn compound with Mg in a very short time after brazing. Moreover, when it adds to a sacrificial material in order to make an electric potential base, the electric potential difference with a core material becomes large, and there exists an effect (effect which reduces corrosion depth) which improves the corrosion resistance of a brazing sheet. However, if the addition amount is less than the lower limit, the effect is not sufficiently exerted, and if the upper limit is exceeded, the melting point decreases, or the corrosion rate becomes too fast and the sacrificial material layer disappears early, resulting in the corrosion depth It will increase (pitting corrosion resistance will decrease). For this reason, content of Zn shall be 4.1-7.5 mass%. More preferably, it is 4.5-7.0 mass%, More preferably, it is 4.8-6.8 mass%.

（Ｍｇ）
Ｍｇは、ろう付時に芯材へ拡散して、ＭｇとＳｉが共存する領域において、Ｓｉと微細なＭｇ−Ｓｉ化合物を形成して材料の強度を向上させる効果がある。しかし、その添加量が下限未満ではその効果が十分発揮されず、上限を超えるとろう付性が低下してしまう。このため、Ｍｇの含有量は１．２〜２．５質量％とする。より好ましくは１．２〜２．２質量％であり、さらに好ましくは１．３〜２．０質量％である。 (Mg)
Mg diffuses into the core during brazing, and has an effect of improving the strength of the material by forming a fine Mg—Si compound with Si in the region where Mg and Si coexist. However, when the addition amount is less than the lower limit, the effect is not sufficiently exhibited, and when the addition amount exceeds the upper limit, the brazing property is deteriorated. For this reason, content of Mg shall be 1.2-2.5 mass%. More preferably, it is 1.2-2.2 mass%, More preferably, it is 1.3-2.0 mass%.

（Ｓｉ）
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、その添加量が下限未満ではその効果が十分発揮されず、上限を超えると犠牲材の融点が低下してろう付時に犠牲材が溶融してしまう。このため、Ｓｉの含有量は０．１〜０．４質量％とする。より好ましくは０．１３〜０．３５質量％であり、さらに好ましくは０．１５〜０．３２質量％である。 (Si)
Si has the effect of improving the strength of the material by forming a fine Mg-Si compound with Mg. However, if the addition amount is less than the lower limit, the effect is not sufficiently exhibited. If the addition amount exceeds the upper limit, the melting point of the sacrificial material is lowered and the sacrificial material is melted during brazing. For this reason, content of Si shall be 0.1-0.4 mass%. More preferably, it is 0.13-0.35 mass%, More preferably, it is 0.15-0.32 mass%.

＜ろう材＞
ろう材の組成としては特に限定されるものではなく、Ａｌ−Ｓｉ系合金、Ａｌ−Ｓｉ−Ｚｎ系合金の一般的にろう材として使用されているものを適用することができる。例えば、ＪＩＳ４０４５合金、４３４３合金、４０４７合金等が挙げられる。また、これらＪＩＳ４０４５合金，４３４３合金，４０４７合金等にＺｎを含有する合金、またＭｇ、Ｃｕ、Ｌｉ等を含有する合金を用いることもできる。 <Brazing material>
The composition of the brazing material is not particularly limited, and an Al—Si based alloy or an Al—Si—Zn based alloy generally used as a brazing material can be applied. For example, JIS4045 alloy, 4343 alloy, 4047 alloy etc. are mentioned. In addition, an alloy containing Zn or an alloy containing Mg, Cu, Li, or the like can be used for these JIS 4045 alloy, 4343 alloy, 4047 alloy and the like.

＜芯材の平均結晶粒径＞
以上の成分組成を有する芯材２において、そのろう付後の平均結晶粒径は、３０〜２００μｍの範囲内とされる。
ろう付熱処理後の芯材２の結晶粒径が微細なほど、犠牲材３から芯材２へのＭｇ拡散が促進されるため材料の強度が向上する効果がある。しかし、結晶粒径が微細すぎると、Ｍｇ拡散が促進されすぎてろう付性が低下したり、ろう材４側の耐ろう侵食性が低下してしまう。また、上限を超えるとＭｇ拡散を促進する効果が十分に得られない。 <Average crystal grain size of core material>
In the core material 2 having the above component composition, the average crystal grain size after brazing is in the range of 30 to 200 μm.
As the crystal grain size of the core material 2 after the brazing heat treatment is finer, Mg diffusion from the sacrificial material 3 to the core material 2 is promoted, so that the strength of the material is improved. However, if the crystal grain size is too fine, Mg diffusion is promoted too much and the brazing property is lowered, or the brazing corrosion resistance on the brazing material 4 side is lowered. On the other hand, if the upper limit is exceeded, the effect of promoting Mg diffusion cannot be sufficiently obtained.

＜Ｍｇに対するＺｎの添加量比＞
犠牲材３のＭｇ添加量に対してＺｎ添加量は、Ｚｎ／Ｍｇ≧３とされる。
Ｓｉ量が０．４％以下、Ｍｇ量が１．２％以上の範囲にある合金において、Ｚｎ／Ｍｇ比を３以上とすると、ろう付後のごく短時間にＭｇとＺｎがＭｇ−Ｚｎ化合物を形成しやすくろう付直後の強度を向上させる効果がある。 <Ratio of Zn addition to Mg>
The Zn addition amount is Zn / Mg ≧ 3 with respect to the Mg addition amount of the sacrificial material 3.
In an alloy having an Si content of 0.4% or less and an Mg content of 1.2% or more, if the Zn / Mg ratio is 3 or more, Mg and Zn are converted into an Mg—Zn compound in a very short time after brazing. It is easy to form and has the effect of improving the strength immediately after brazing.

＜クラッド材の製造工程＞
芯材用アルミニウム合金、犠牲材用アルミニウム合金、およびろう材用合金を鋳造し、得られた芯材、犠牲材およびろう材について所定温度で均質化処理を行う。
そして、芯材の鋳塊の片面に犠牲材鋳塊を、さらに反対面にろう材鋳塊を組み合わせて熱間圧延し、クラッド材とする。さらに所定の厚さまで冷間圧延を行い、その後、中間焼鈍を行い、最終の冷間圧延により所望の厚さのクラッド材１を作製する。
均質化処理の条件としては特に限定されるものではないが、芯材については例えば５３０〜６００℃で８〜１６時間とされる。また、中間焼鈍の条件としては３００〜４００℃で１〜６時間が好ましいが、これに限定されるものではない。また、クラッド材１としての構成は、厚さの比で、例えば、犠牲材３：芯材２：ろう材４＝２０％：７０％：１０％とされるが、クラッド率はこれに限定されるものではなく、犠牲材３のクラッド率を１５％や１７％にしてもよい。 <Manufacturing process of clad material>
An aluminum alloy for the core material, an aluminum alloy for the sacrificial material, and an alloy for the brazing material are cast, and the obtained core material, the sacrificial material, and the brazing material are homogenized at a predetermined temperature.
And a sacrificial material ingot is combined with one side of the ingot of the core material, and a brazing material ingot is further combined with the opposite surface, and hot rolled to obtain a clad material. Further, cold rolling is performed to a predetermined thickness, followed by intermediate annealing, and a clad material 1 having a desired thickness is produced by final cold rolling.
Although it does not specifically limit as conditions of a homogenization process, About a core material, it shall be 8-16 hours at 530-600 degreeC, for example. Moreover, as conditions of intermediate annealing, although 1 to 6 hours are preferable at 300-400 degreeC, it is not limited to this. The clad material 1 has a thickness ratio of, for example, sacrificial material 3: core material 2: brazing material 4 = 20%: 70%: 10%, but the clad rate is limited to this. Instead, the clad rate of the sacrificial material 3 may be 15% or 17%.

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、およびろう材用合金（ＪＩＳ４０４５合金）を鋳造した。得られた芯材、犠牲材およびろう材は前述した範囲内の所定温度で均質化処理を行った。
そして、芯材の鋳塊の片面に犠牲材鋳塊を、さらに反対面にろう材鋳塊を組み合わせて熱間圧延し、クラッド材とした。さらに所定の厚さまで冷間圧延を行った。その後、中間焼鈍を３５０℃で６時間行い、最終の冷間圧延により厚さ０．２０ｍｍのＨ１４調質のクラッド材を作製した。犠牲材が４０μｍ、芯材が１４０μｍ、ろう材が２０μｍであった。表１中の組成の％は質量％である。
得られたクラッド材に対して、ろう付熱処理後の芯材の結晶粒径、ろう付後強度、時効硬化後の強度、フィンの接合率、耐ろう侵食性（エロージョン深さ）、ろう付熱処理後の犠牲材の溶融の有無、腐食試験による内部耐食性を以下のようにして測定した。 Aluminum alloy for core material, aluminum alloy for sacrificial material, and alloy for brazing material (JIS 4045 alloy) were cast by semi-continuous casting. The obtained core material, sacrificial material and brazing material were homogenized at a predetermined temperature within the above-mentioned range.
Then, a sacrificial material ingot was combined with one side of the ingot of the core material, and a brazing material ingot was further combined with the opposite surface to perform hot rolling to obtain a clad material. Furthermore, cold rolling was performed to a predetermined thickness. Then, intermediate annealing was performed at 350 ° C. for 6 hours, and a H14 tempered clad material having a thickness of 0.20 mm was produced by final cold rolling. The sacrificial material was 40 μm, the core material was 140 μm, and the brazing material was 20 μm. The percentage of the composition in Table 1 is mass%.
For the obtained clad material, the crystal grain size of the core material after brazing heat treatment, the strength after brazing, the strength after age hardening, the bonding rate of fins, the brazing corrosion resistance (erosion depth), the brazing heat treatment The presence or absence of subsequent sacrificial material melting and internal corrosion resistance by a corrosion test were measured as follows.

（ろう付熱処理後の結晶粒径）
作製したクラッド材を高純度窒素ガス雰囲気中でドロップ形式で６００℃×３分のろう付相当熱処理（室温から６００℃まで昇温時間は５〜７分）を施した。ろう付相当熱処理を実施したサンプルは圧延方向平行断面を樹脂埋め後、鏡面に研磨した後、エッチング液で結晶粒を現出させ、試料の３箇所について芯材を光学顕微鏡で１００倍、結晶粒径が微細で観察が困難なものについては２００倍で写真撮影した。撮影した写真から圧延方向について切断法で結晶粒径を測定した。 (Crystal grain size after brazing heat treatment)
The clad material thus produced was subjected to brazing equivalent heat treatment (increase temperature from room temperature to 600 ° C. for 5 to 7 minutes) in a drop form in a high purity nitrogen gas atmosphere at 600 ° C. for 3 minutes. The sample subjected to the brazing equivalent heat treatment is filled with resin in the rolling direction parallel cross section and polished to a mirror surface, and then crystal grains are revealed with an etching solution. For those having a small diameter and difficult to observe, a photograph was taken at 200 times. From the photograph taken, the crystal grain size was measured by the cutting method in the rolling direction.

（ろう付後強度、時効硬化後の強度）
作製したクラッド材を高純度窒素ガス雰囲気中でドロップ形式で６００℃×３分のろう付相当熱処理（室温から６００℃まで昇温時間は５〜７分）を施した。ろう付直後の強度を測定するための試料として２５℃で１日放置後、また、時効硬化後の強度を測定するための試料としてさらに８０℃で７日時効処理を施した後に、圧延方向と平行にサンプルを切り出し、ＪＩＳ１３号Ｂ試験片を作製し、引張試験を実施して引張強さを測定した。
表１中、ろう付直後の強度を直後強度、時効硬化後の強度を時効後強度として示す。また、その評価として、ろう付直後の強度としては、１８０ＭＰａ未満であったものを×、１８０ＭＰａ以上１８５ＭＰａ未満であったものを○、１８５ＭＰａ以上であったものを◎とした。時効硬化後の強度としては、２１０ＭＰａ未満であったものを×、２１０ＭＰａ以上２３０ＭＰａ未満であったものを○、２３０ＭＰａ以上であったものを◎とした。 (Strength after brazing, strength after age hardening)
The clad material thus produced was subjected to brazing equivalent heat treatment (increase temperature from room temperature to 600 ° C. for 5 to 7 minutes) in a drop form in a high purity nitrogen gas atmosphere at 600 ° C. for 3 minutes. As a sample for measuring the strength immediately after brazing, after standing at 25 ° C. for 1 day, and as a sample for measuring the strength after age hardening, further subjected to 7-day aging treatment at 80 ° C. A sample was cut out in parallel to prepare a JIS No. 13 B test piece, and a tensile test was performed to measure the tensile strength.
In Table 1, the strength immediately after brazing is shown as the strength immediately after brazing, and the strength after age hardening is shown as the strength after aging. In addition, as the evaluation, the strength immediately after brazing was rated as x when it was less than 180 MPa, ◯ when it was 180 MPa or more and less than 185 MPa, and ◎ when it was 185 MPa or more. The strength after age hardening was rated as x when it was less than 210 MPa, ◯ when it was 210 MPa or more and less than 230 MPa, and ◎ when it was 230 MPa or more.

（フィンの接合率）
作製したクラッド材を板厚０．０６ｍｍのＡｌ−Ｍｎ−Ｚｎ系ベアフィン材と組み合わせてミニコア試験片を作製し、浸漬塗布でフラックスを５ｇ／ｍ^２相当塗布した後、高純度窒素ガス雰囲気中で６００℃×３分のろう付熱処理（室温から６００℃まで昇温時間は５〜７分）を施した。接合率は、ろう付けする接合面において、接合すべき全面積から空隙等の未接合部が形成された部分の面積を差し引いた実際の接合面積が、接合すべき全面積に占める割合として求めた。その結果、接合率が９０％未満であったものを×、９０％以上９５％未満であったものを○、９５％以上であったものを◎とした。 (Fin joining rate)
The produced clad material is combined with an Al—Mn—Zn-based bare fin material having a plate thickness of 0.06 mm to produce a mini-core test piece, and after applying flux equivalent to 5 g / m ² by dip coating, in a high purity nitrogen gas atmosphere A brazing heat treatment at 600 ° C. for 3 minutes (temperature rising time from room temperature to 600 ° C. was 5 to 7 minutes) was performed. The bonding rate was determined as the ratio of the actual bonding area, which is obtained by subtracting the area of the unbonded part such as the gap from the total area to be bonded, to the total area to be bonded. . As a result, the case where the joining rate was less than 90% was rated as x, the case where it was 90% or more and less than 95% was rated as ◯, and the case where it was 95% or more was rated as ◎.

（耐ろう侵食性（エロージョン深さ））
作製した材料を高純度窒素ガス雰囲気中でドロップ形式で６００℃×３分のろう付相当熱処理（室温から６００℃まで昇温時間は５〜７分）を施した。ろう付相当熱処理を実施したサンプルを樹脂埋めし、圧延方向平行断面を鏡面研磨し、バーカー氏液で組織を現出後、光学顕微鏡で観察してろう侵食深さ（ろう材表面からの深さ）を測定した。図２はその顕微鏡写真であり、ろう侵食深さをＨで示す。侵食深さが６０μｍ以上であったものを×、６０μｍ未満であったものを○とした。 (Wax erosion resistance (erosion depth))
The prepared material was subjected to brazing equivalent heat treatment in a drop form in a high-purity nitrogen gas atmosphere at 600 ° C. for 3 minutes (the temperature rising time from room temperature to 600 ° C. was 5 to 7 minutes). The sample subjected to brazing equivalent heat treatment was filled with resin, the cross-section parallel to the rolling direction was mirror-polished, the structure was revealed with Barker's solution, and then observed with an optical microscope to observe the depth of brazing erosion (depth from the brazing material surface). ) Was measured. FIG. 2 is a photomicrograph of the wax erosion depth indicated by H. The case where the erosion depth was 60 μm or more was rated as x, and the case where the erosion depth was less than 60 μm was rated as ◯.

（犠牲材の溶融）
作製した材料を高純度窒素ガス雰囲気中でドロップ形式で６００℃×３分のろう付相当熱処理（室温から６００℃まで昇温時間は５〜７分）を施した。ろう付相当熱処理を実施したサンプルを樹脂埋めし、圧延方向平行断面を鏡面研磨し、バーカー氏液で組織を現出後、犠牲材の溶融の有無を観察した。ろう付相当熱処理時に犠牲材が溶融したものを×、未溶融のものを○とした。 (Sacrificial material melting)
The prepared material was subjected to brazing equivalent heat treatment in a drop form in a high-purity nitrogen gas atmosphere at 600 ° C. for 3 minutes (the temperature rising time from room temperature to 600 ° C. was 5 to 7 minutes). The sample subjected to the brazing equivalent heat treatment was filled with resin, the cross-section parallel to the rolling direction was mirror-polished, the structure was revealed with Barker's solution, and the presence or absence of melting of the sacrificial material was observed. The case where the sacrificial material was melted during the brazing equivalent heat treatment was rated as x, and the case where the sacrificial material was not melted was marked as ◯.

（内部耐食性（腐食深さ））
ろう付熱処理後のサンプルから３０×５０ｍｍのサンプルを切り出し、ろう材側についてはマスキングし、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。その腐食深さが総板厚の半分以上であったものを×、腐食深さが総板厚の半分未満であったものを○とした。 (Internal corrosion resistance (corrosion depth))
A 30 × 50 mm sample is cut out from the sample after brazing heat treatment, the brazing material side is masked, and the sacrificial material side is Cl ⁻ : 195 ppm, SO ₄ ²⁻ : 60 ppm, Cu ²⁺ : 1 ppm, Fe ³⁺ : 30 ppm. The immersion test was carried out for 8 weeks in a solution containing 80 ° C. × 8 hours → room temperature × 16 hours. The sample after the corrosion test was immersed in a boiled chromic phosphate mixed solution to remove the corrosion products, and then the cross-section observation of the maximum corrosion portion was performed to measure the corrosion depth. The case where the corrosion depth was more than half of the total plate thickness was rated as x, and the case where the corrosion depth was less than half the total plate thickness was rated as ◯.

（総合評価）
以上の各試験結果より、ろう付直後の強度が◎、時効後の強度が◎、フィン接合率が◎、ろう侵食が○、犠牲材の溶融が○、耐食性が○であったものを総合評価◎とし、ろう付直後の強度が○以上、時効後の強度が○以上、フィン接合率が○以上、ろう侵食が○、犠牲材の溶融が○、耐食性が○を総合評価○、いずれかの項目に×があるものを総合評価×とした。 (Comprehensive evaluation)
Based on the above test results, the overall evaluation was that the strength immediately after brazing was ◎, the strength after aging was ◎, the fin joint rate was ◎, the brazing corrosion was ○, the sacrificial material was melted, and the corrosion resistance was ○. ◎, the strength immediately after brazing is ○ or higher, the strength after aging is ○ or higher, the fin joint ratio is ○ or higher, brazing corrosion is ○, sacrificial material melting is ○, corrosion resistance is ○ Items with x in the item were regarded as comprehensive evaluation x.

この表１において、Ｎｏ．１，５，６，１１，１２，１６，２０〜２２は、ろう付後強度、時効硬化後の強度、フィンの接合率、耐ろう侵食性、ろう付熱処理後の犠牲材の溶融の有無、腐食試験による内部耐食性のいずれかにおいて劣っており、これら以外のクラッド材は、総合評価が○以上であり、ろう付性が良好で、犠牲材の融点を満足しつつろう付直後の強度が高く、かつ時効硬化性に優れ、使用中にも高強度が得られることがわかった。 In Table 1, no. 1, 5, 6, 11, 12, 16, 20 to 22 are strength after brazing, strength after age hardening, bonding rate of fins, brazing corrosion resistance, presence or absence of melting of sacrificial material after brazing heat treatment, The internal corrosion resistance is inferior in any of the corrosion tests, and other clad materials have a comprehensive evaluation of ◯ or higher, good brazing properties, and high strength immediately after brazing while satisfying the melting point of the sacrificial material. In addition, it was found that the composition was excellent in age-curing property and high strength was obtained even during use.

なお、本発明は上記実施形態に限定されるものではなく、本発明の趣旨を逸脱しない範囲において種々の変更を加えることが可能である。 In addition, this invention is not limited to the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.

１アルミニウム合金クラッド材
２芯材
３犠牲材
４ろう材 1 Aluminum alloy clad material 2 Core material 3 Sacrificial material 4 Brazing material

Claims

An aluminum alloy clad material in which a sacrificial material is clad on one surface of a core material and a brazing material is clad on the other surface, the sacrificial material comprising Zn: 4.1-7.5 mass%, Mg: 1.2 -2.5 mass%, Si: 0.1-0.4 mass% is contained, the remainder consists of Al and inevitable impurities, and the core material is Mn: 1.0-1.8 mass% , Si: 0.5 to 1.2% by mass, Fe: 0.1 to 0.4% by mass, Cu: 0.5 to 1.5% by mass, with the balance consisting of Al and inevitable impurities, further, the average crystal grain size after brazing of said core material Ri range near the 30 to 200 [mu] m, characterized by the Zn amount and Zn / Mg ≧ 3 with respect to Mg addition amount of the sacrificial material Aluminum alloy clad material