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JP2001020028A - Aluminum alloy cast and forged material excellent in grain boundary corrosion resistance - Google Patents

Aluminum alloy cast and forged material excellent in grain boundary corrosion resistance

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Publication number
JP2001020028A
JP2001020028A JP19346899A JP19346899A JP2001020028A JP 2001020028 A JP2001020028 A JP 2001020028A JP 19346899 A JP19346899 A JP 19346899A JP 19346899 A JP19346899 A JP 19346899A JP 2001020028 A JP2001020028 A JP 2001020028A
Authority
JP
Japan
Prior art keywords
cast
aluminum alloy
alloy
film
corrosion resistance
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP19346899A
Other languages
Japanese (ja)
Inventor
Fumihiro Sato
文博 佐藤
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kobe Steel Ltd
Original Assignee
Kobe Steel Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Kobe Steel Ltd filed Critical Kobe Steel Ltd
Priority to JP19346899A priority Critical patent/JP2001020028A/en
Publication of JP2001020028A publication Critical patent/JP2001020028A/en
Pending legal-status Critical Current

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  • Chemical Treatment Of Metals (AREA)
  • Other Surface Treatments For Metallic Materials (AREA)

Abstract

PROBLEM TO BE SOLVED: To improve grain boundary corrosion resistance and stress corrosion resistance, etc., even in the case of containing Cu, by arranging a hydrate-oxide film of Al having the specified thickness on the surface of a cast and forged material. SOLUTION: The thickness of the hydrate-oxide film of Al arranged on the surface of the Al alloy is made to 100-800 Å. The Al alloy to be applied, contains >=0.05% Cu, and has desirably >=280 N/mm2 the average value of proof stress (σ 0.2) in artificial aging-hardening treatment, >=20 J/cm2 the average value of Charpy impact value as the forged material. Further, the alloy has desirably >=230 N/mm2 the average value of the σ 0.2>=12 J/cm2 the average value of Charpy impact value and >=18% elongation as the cast material. For satisfying the characteristics, as the forged material, the Al alloy is desirable to contain, by mass %, 0.6-1.6% Mg and 0.8-1.8% Si. Further, as the cast material, the Al alloy is desirable to contain 2.0% Si and cast with a high pressure casting method and to be the one applied with a solution heat treatment and the artificial aging-hardening treatment.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【0001】[0001]

【発明の属する技術分野】本発明は、耐粒界腐食性に優
れたアルミニウム合金鋳鍛材( 以下、アルミニウムを単
にAlと言う) に関するものである。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy cast and forged material having excellent intergranular corrosion resistance (hereinafter, aluminum is simply referred to as Al).

【0002】[0002]

【従来の技術】近年、排気ガス等による地球環境問題に
対し、車両、船舶、航空機、自動二輪あるいは自動車な
どの輸送機車体の軽量化による燃費の向上が追求されて
いる。このため、輸送機車体の構造材やパネル、フレー
ム材などへのAl合金材の使用も増加しつつある。
2. Description of the Related Art In recent years, with respect to global environmental problems due to exhaust gas and the like, improvement in fuel efficiency by reducing the weight of transport vehicles such as vehicles, ships, aircraft, motorcycles, and automobiles has been pursued. For this reason, the use of Al alloy materials for structural materials, panels, frame materials, etc. of transport vehicle bodies is also increasing.

【0003】例えば、自動二輪や自動車のホイールやナ
ックル、ロアアーム、アッパーアーム等のサスペンショ
ン部品などの、複雑な形状や厚肉部を有する構造材に
は、安価でかつ必要な強度や靱性を有することから、Al
合金鋳造材や鍛造材 (本発明ではこれらを総称して鋳鍛
材と言う) が使用されている。
For example, structural materials having complicated shapes and thick portions, such as motorcycles, automobile wheels, suspension parts such as knuckles, lower arms, and upper arms, are inexpensive and have the necessary strength and toughness. From, Al
Alloy castings and forgings (these are collectively referred to as cast forgings in the present invention) are used.

【0004】これら構造材用のAl合金鋳鍛材としては、
Siを6.5 〜7.5% (質量% 、以下同じ) 含む、AA乃至JIS
AC4CH などの Al-Si-Mg 系Al合金鋳造材や、時効硬化性
やリサイクル性に優れたAA乃至JIS 6000系(Al-Si-Mg
系) のAl合金鍛造材などが代表的である。
[0004] Cast Al alloys for these structural materials include:
AA to JIS containing 6.5 to 7.5% (mass%, the same applies hereinafter) of Si
Al-Si-Mg-based Al alloy castings such as AC4CH, and AA to JIS 6000-based (Al-Si-Mg
A typical example is an aluminum alloy forged material.

【0005】近年、これらAl合金鋳鍛材には、より薄肉
化するとともに、より高強度化、高靱性化することが求
められている。この要求に対し、Al合金鋳鍛材の側を高
性能化する場合、Al合金鋳鍛材が対象とする構造材は、
前記した通り、複雑な形状を有したり、厚肉の場合が多
いため、熱処理等の製造条件のみで高強度化や高靱性化
することには限界がある。
[0005] In recent years, it has been demanded that these Al alloy cast and forged materials be made thinner and higher in strength and toughness. In response to this requirement, when improving the performance of the Al alloy cast forging side, the structural material targeted by the Al alloy cast forging is:
As described above, since they often have a complicated shape or are thick, there is a limit to achieving high strength and high toughness only by manufacturing conditions such as heat treatment.

【0006】このため、従来から、Cuのような強化元素
を添加する手法が汎用されている。例えば、前記AC4CH
などの Al-Si-Mg 系Al合金鋳造材では、通常、Cuが0.05
% 以上、0.20% を上限として含まれている。また、他の
AC4 系も含めて、より高靱性化が必要な場合には、4.0%
までのCuが添加される。更に、Al-Si-Mg系Al合金鍛造材
でも、高靱性化が必要な場合には、通常、Cuが0.05% 以
上、0.40% 程度までのCuが添加されている。
For this reason, conventionally, a method of adding a strengthening element such as Cu has been widely used. For example, the AC4CH
In Al-Si-Mg-based Al alloy castings such as
% And 0.20% is included as the upper limit. Also other
4.0% if higher toughness is required, including AC4
Up to Cu is added. Further, even in the case of forged Al-Si-Mg-based Al alloy, when toughness is required, Cu is usually added at 0.05% or more and up to about 0.40%.

【0007】しかし、このCuのような強化元素を添加し
た場合には、Al合金鋳鍛材の耐粒界腐食性が劣化すると
いう問題が生じる。Cuを含む場合には、Al合金材料の組
織の、粒界腐食や応力腐食の感受性が著しく高くなるか
らである。
However, when a strengthening element such as Cu is added, there arises a problem that the intergranular corrosion resistance of the cast aluminum alloy forging deteriorates. This is because when Cu is contained, the susceptibility of the structure of the Al alloy material to intergranular corrosion and stress corrosion becomes extremely high.

【0008】一方、特に、輸送機用の構造材部品など
は、重要保安部品であるため、使用環境として塩水腐食
環境下での耐食性を想定して評価される。しかも、構造
材としては、一定の応力負荷状態或いは応力が集中しや
すい状態で使用されることが多い。
On the other hand, in particular, structural material parts for transport aircraft are important security parts, and thus are evaluated assuming corrosion resistance in a salt water corrosion environment as a use environment. Moreover, as a structural material, it is often used under a certain stress load state or a state where stress tends to concentrate.

【0009】更に、構造材としてのAl合金鋳鍛材では、
構成がAl合金材のみからなるのではなく、鋼材と接合乃
至組み合わされて用いられることが多い。例えば、自動
車用のサスペンション部品の場合には、Al合金鋳鍛材か
らなるアーム類の両端のリングに挿入されるブッシュに
は、より高強度材が必要な点から、鋼製のブッシュが用
いられる場合がある。そして、このような鋼材と接合さ
れて用いられるAl合金鍛造材は、特に使用中に電位が上
がりやすく、電蝕乃至粒界腐食が生じやすい使用環境と
なっている。
Further, in the case of an aluminum alloy forged material as a structural material,
In many cases, the structure is not only made of an Al alloy material but is used in combination or combination with a steel material. For example, in the case of a suspension part for an automobile, a steel bush is used for a bush inserted into rings at both ends of arms made of an aluminum alloy cast and forged material because a higher strength material is required. There are cases. An aluminum alloy forged material used by being joined to such a steel material has an operating environment in which the potential tends to increase particularly during use, and electric corrosion or intergranular corrosion is likely to occur.

【0010】したがって、特に、輸送機用の構造材用等
のAl合金鋳鍛材には、前記粒界腐食や応力腐食、或いは
更に粒界腐食割れや応力腐食割れ等が発生しやすい使用
環境下にあっても、更に、Al合金鋳鍛材の耐粒界腐食性
を劣化させるCuのような強化元素を添加した場合にも、
粒界腐食や応力腐食割れが生じず、かつ、高強度、高靱
性であるという、厳しい乃至相矛盾しているとも言える
要求特性および技術的課題がある。
[0010] Therefore, in particular, in the use environment in which the above-mentioned intergranular corrosion and stress corrosion, or even intergranular corrosion cracking and stress corrosion cracking, etc., are likely to occur in the cast aluminum alloy forgings for structural materials for transportation equipment. However, even when a strengthening element such as Cu that deteriorates the intergranular corrosion resistance of the Al alloy forged material is added,
There are required characteristics and technical problems that can be said to be severe or inconsistent, such that intergranular corrosion and stress corrosion cracking do not occur, and high strength and high toughness are obtained.

【0011】これに対し、Al合金の材料側 (化学成分や
組織) から鋳鍛材の耐粒界腐食性を向上させることには
限界がある。Al合金鋳鍛材の耐粒界腐食性を向上させよ
うとする場合、強化元素としてのCuを低減することとな
り、その分、前記機械的な要求特性を犠牲にするという
矛盾が生じるからである。
On the other hand, there is a limit to improving the intergranular corrosion resistance of the cast forging from the material side (chemical composition and structure) of the Al alloy. This is because, when trying to improve the intergranular corrosion resistance of the Al alloy cast forging material, Cu as a strengthening element is reduced, and contradiction that sacrifices the mechanical required characteristics occurs. .

【0012】このため、Al合金鋳鍛材の耐粒界腐食性を
向上させるために、従来から、クロメート等の防食皮膜
を設ける表面処理によって、Al合金鋳鍛材の耐粒界腐食
性を向上させることが一般的である。
For this reason, in order to improve the intergranular corrosion resistance of the Al alloy cast forging, the surface treatment of providing an anticorrosion film such as chromate has conventionally been used to improve the intergranular corrosion resistance of the Al alloy cast forging. It is common to let them.

【0013】[0013]

【発明が解決しようとする課題】しかし、クロメート皮
膜の形成のためのクロメート処理には、周知の通り、ク
ロムの廃液の処理の問題があり、クロメート処理に代わ
る表面処理方法が求められている。
However, as is well known, the chromate treatment for forming a chromate film has a problem of treating a chromium waste liquid, and a surface treatment method which is an alternative to the chromate treatment is required.

【0014】クロメート処理以外の表面処理方法として
は、Alの酸化物皮膜、亜鉛めっき皮膜、亜鉛とクロムと
を組み合わせた所謂ダクロ皮膜処理、リン酸塩皮膜処
理、樹脂皮膜 (ビニールシート等を含む) 、リチウム
塩, マグネシウム塩, セリウム塩, カルシウム塩などの
皮膜、過マンガン酸カリウム皮膜などが存在する。
Surface treatment methods other than chromate treatment include Al oxide film, zinc plating film, so-called dacro film treatment combining zinc and chromium, phosphate film treatment, and resin film (including vinyl sheet etc.). , Lithium salts, magnesium salts, cerium salts, calcium salts, etc., and potassium permanganate films.

【0015】しかし、この内、電気乃至置換による亜鉛
めっき皮膜やダクロ皮膜は、犠牲防食の効果はあるもの
の、例えば、輸送機の構造材としての使用時に、薬剤な
どの洗浄を受けた場合に劣化し易く、皮膜自体の耐久性
が劣り、結果的に、耐粒界腐食性を有効に向上させるこ
とができない。
[0015] Among them, the galvanized film and the dacro film formed by electricity or substitution have a sacrificial anticorrosion effect, but deteriorate when they are washed with chemicals or the like, for example, when used as a structural material of a transport machine. Therefore, the durability of the film itself is poor, and as a result, the intergranular corrosion resistance cannot be effectively improved.

【0016】また、Alの酸化皮膜は、更にAl合金鋳鍛材
が塗装されて構造材として使用される場合に、樹脂塗膜
との密着性が劣り、塗膜のつきまわり性を阻害するとと
もに、塗膜ふくれなどを生じやすく、塗装後の耐蝕性が
劣る。また、Alの酸化皮膜を設けたAl合金鋳鍛材を構造
材に加工する際に、成形性や溶接性を阻害しやすく、不
適である。
In addition, when an Al alloy cast and forged material is further applied and used as a structural material, the oxide film of Al is inferior in adhesion to a resin coating film, hinders the throwing power of the coating film, and , Coating film swelling, etc., and poor corrosion resistance after painting. Further, when an Al alloy cast forging material provided with an Al oxide film is processed into a structural material, formability and weldability are easily impaired, which is not suitable.

【0017】樹脂皮膜は、耐粒界腐食性の抑制効果は期
待できるものの、皮膜の密着性を保証するための被覆工
程が煩雑となるとともに、コストがかかり、経済的かつ
実用的ではない。また、塗装して使用する際の、電着塗
装性や塗膜の密着性が低く、実質的に塗装できない。
Although the resin film can be expected to have an effect of suppressing intergranular corrosion resistance, the coating process for ensuring the adhesion of the film becomes complicated, costs are high, and is not economical and practical. In addition, when coated and used, the electrodeposition coating property and the adhesion of the coating film are low, and the coating cannot be performed substantially.

【0018】したがって、これら、いずれの表面処理方
法には、各々問題があり、構造材用のAl合金鋳鍛材の耐
粒界腐食性を向上させるためのクロメート処理に代わる
表面処理方法としては、未だ実用化されていないのが実
情である。
Therefore, each of these surface treatment methods has its own problem. As a surface treatment method that can replace the chromate treatment for improving the intergranular corrosion resistance of the cast aluminum alloy forging for structural materials, The fact is that it has not yet been put to practical use.

【0019】本発明はこの様な事情に着目してなされた
ものであって、その目的は、Cu添加を添加しても、耐粒
界腐食性や耐応力腐食性等の耐食性を向上させた、構造
材用Al合金鋳鍛材を提供することである。
The present invention has been made in view of such circumstances, and its purpose is to improve corrosion resistance such as intergranular corrosion resistance and stress corrosion resistance even when Cu is added. Another object of the present invention is to provide an aluminum alloy cast and forged material for a structural material.

【0020】[0020]

【課題を解決するための手段】この目的を達成するため
に、本発明の要旨は、Cu:0.05%以上を含み、構造材に用
いるAl合金鋳鍛材であって、鋳鍛材表面に、膜厚が100
〜8000Å (オングストローム) のAlの水和酸化物皮膜を
設けたことである。
In order to achieve this object, the gist of the present invention is to provide an Al alloy casting and forging material containing Cu: 0.05% or more and used for a structural material, 100 film thickness
This means that a hydrated oxide film of Al of ~ 8000Å (angstrom) was provided.

【0021】本発明では、Al合金鋳鍛材の外表面にAlの
水和酸化物皮膜を設け、Al合金表面と腐食環境雰囲気と
を絶縁し、Al合金鋳鍛材の耐粒界腐食性や耐応力腐食性
等の耐食性を向上させる。
According to the present invention, a hydrated oxide film of Al is provided on the outer surface of the cast Al alloy to insulate the surface of the Al alloy from the corrosive environment. Improves corrosion resistance such as stress corrosion resistance.

【0022】また、Alの水和酸化物皮膜は、Alの酸化物
皮膜と同様に、化成処理などの薬剤に対し、非反応性で
皮膜自体が耐食性に優れるという特性も有する。このた
め、構造材として、基本的には無塗装で使用が可能であ
る利点も有する。また、輸送機の構造材としての使用時
に、亜鉛めっき皮膜などのように、薬剤などの洗浄を受
けても劣化することがなく、耐久性があるため、長期に
渡る防食効果が期待できる。
Further, the hydrated oxide film of Al, like the oxide film of Al, also has the property that it is non-reactive with chemicals such as chemical conversion treatment and the film itself has excellent corrosion resistance. For this reason, there is also an advantage that it can be used basically as a structural material without painting. Further, when used as a structural material of a transport machine, unlike a galvanized film, it does not deteriorate even if it is washed with a chemical or the like, and since it has durability, a long-term anticorrosion effect can be expected.

【0023】しかも、構造材用として、Al合金鋳鍛材が
塗装された場合にも、Alの酸化物皮膜のような、樹脂塗
膜との密着性が劣り、塗膜のつきまわり性を阻害すると
ともに、塗膜ふくれなどを生じやすく、塗装後の耐蝕性
が劣るようなことがなく、良好な塗膜密着性と塗膜の耐
食性を保証することが可能である。そして、Alの酸化物
皮膜のような成形加工性や溶接性を阻害することもな
い。
Moreover, even when an aluminum alloy cast and forged material is applied for structural materials, the adhesion to a resin coating film such as an oxide film of Al is poor, and the throwing power of the coating film is impaired. At the same time, the coating film is easily blistered and the corrosion resistance after coating is not deteriorated, and it is possible to guarantee good coating film adhesion and corrosion resistance of the coating film. Also, there is no hindrance to the formability and weldability of the Al oxide film.

【0024】更に、Alの水和酸化物皮膜は、皮膜の特性
が優れるとともに、後述する高温水や水蒸気に直接接触
させる方法などにより、安価かつ簡便に皮膜形成処理が
可能であり、廃液処理の問題もない点、工業的に他の皮
膜よりも優れている。例えば、クロメート皮膜、樹脂皮
膜、リチウム塩, マグネシウム塩, セリウム塩, カルシ
ウム塩などの皮膜、過マンガン酸カリウム皮膜それ以外
の前記皮膜は、Al合金材表面に設ける際の、皮膜の密着
性、あるいは、成形加工性や溶接性の点で、Alの水和酸
化物に比して劣る。また、Alの水和酸化物に比して、総
じて皮膜処理 (薬液等) のコストが高くなり、クロメー
ト皮膜などは、実際に、塗装下地処理として汎用されて
いるものの、処理液の廃液処理のコストが高くなるとい
う問題もある。
Further, the hydrated oxide film of Al has excellent film properties, and can be easily and inexpensively formed by a method of directly contacting high-temperature water or steam as described later. It has no problems and is industrially superior to other coatings. For example, a chromate film, a resin film, a film of a lithium salt, a magnesium salt, a cerium salt, a calcium salt, and the like, a potassium permanganate film, and the other films described above, when provided on the surface of the Al alloy material, the adhesion of the film, or It is inferior to hydrated oxides of Al in terms of formability and weldability. In addition, the cost of film treatment (chemical solution, etc.) is generally higher than that of hydrated oxides of Al. There is also a problem that costs are high.

【0025】[0025]

【発明の実施の形態】(Alの水和酸化物皮膜)本発明にお
いて、Al合金材表面に設けるAlの水和酸化物皮膜とは、
一般式、Al 2O3 ・XH2Oで表され、Alの酸化物の水和反応
により生成したAlの水和酸化物の皮膜を言う。そして、
本発明におけるAlの水和酸化物とは、水和の程度(Xの
値) などによる水和酸化物の種類や、形態、結晶構造や
結晶度などに特に限定されるものではない。ただ、Alの
水和酸化物の中でも、前記X の値が約1.5 〜1.9 の擬ベ
ーマイトのものは、ベーマイト皮膜と一般的に総称され
ている。
DESCRIPTION OF THE PREFERRED EMBODIMENTS (Hydrated oxide film of Al)
Therefore, the hydrated oxide film of Al provided on the surface of the Al alloy material is
General formula, Al TwoOThree・ XHTwoHydration reaction of Al oxide represented by O
Refers to a film of a hydrated oxide of Al generated by the above method. And
The hydrated oxide of Al in the present invention refers to the degree of hydration (X
Value, etc.), morphology, crystal structure,
There is no particular limitation on crystallinity and the like. Just Al
Among the hydrated oxides, the pseudo-base in which the value of X is about 1.5 to 1.9.
-Mite is generally called boehmite film.
ing.

【0026】そして、これらのAlの水和酸化物の皮膜構
造の同定は、前記走査型電子顕微鏡による形態的な観察
の他に、赤外線分光分析法(FT −IR) で行うことができ
る。即ち、FT−IRにより、3000〜3700cm-1付近に認めら
れるAlO ←→H の伸縮振動による吸収スペクトル、およ
び1000〜1050cm-1付近に認められるAl←→OHの伸縮振動
による吸収スペクトル、更に800 〜600cm -1付近に認め
られるOAl ←→O の伸縮振動による吸収スペクトルの、
いずれか一つ以上が認められることにより、本発明のAl
の水和酸化物皮膜の存在が確認される。
The film structure of these hydrated oxides of Al can be identified by infrared spectroscopy (FT-IR) in addition to the morphological observation by the scanning electron microscope. That is, by FT-IR, AlO found in the vicinity 3000~3700cm -1 ← → absorption spectrum due to stretching vibration of H, and 1000~1050cm are found in the vicinity of -1 Al ← → absorption spectrum due to stretching vibrations of OH, further 800 Absorption spectrum due to stretching vibration of OAl ← → O observed around ~ 600 cm -1
Any one or more are recognized, the Al of the present invention
The presence of a hydrated oxide film is confirmed.

【0027】また、Alの水和酸化物皮膜の膜厚は、Al合
金材の破面 (例えばAl合金押出材の180 °曲げによる破
面) を前記した走査型電子顕微鏡による2 万倍以上の観
察で行うことができる。なお、この倍率は、Alの水和酸
化物皮膜の膜厚が薄くなるに従い、より高倍率とする必
要がある。この他、X 線回折によってもAlの水和酸化物
皮膜の同定は可能であり、透過型電子顕微鏡によっても
形態的な観察が可能である。
The hydrated oxide film of Al has a thickness of at least 20,000 times that of a fractured surface of an Al alloy material (for example, a fractured surface of an extruded Al alloy caused by 180 ° bending) by the above-mentioned scanning electron microscope. It can be done by observation. This magnification needs to be higher as the thickness of the hydrated oxide film of Al becomes thinner. In addition, the hydrated oxide film of Al can be identified by X-ray diffraction, and morphological observation is possible by transmission electron microscope.

【0028】更に、本発明におけるAlの水和酸化物皮膜
とは、Al2O3 ・XH2Oの純粋なAlの水和酸化物からのみ構
成される皮膜だけではなく、Alの水和酸化物皮膜を主成
分とするものであれば、混合物、即ち、Alの水和酸化物
皮膜形成時に混入してくる可能性や必然性のある不純物
元素などを含むものであっても構わない。
Further, the hydrated oxide film of Al in the present invention means not only a film composed only of pure Al hydrated oxide of Al 2 O 3 .XH 2 O, but also a hydrated oxide of Al. As long as it is mainly composed of a material film, it may be a mixture, that is, a material containing an impurity element which may possibly be mixed in or form an Al hydrated oxide film.

【0029】例えば、Alの水和酸化物と、Fe、Ni、Co、
Znから選択される1 種以上の金属化合物との複合皮膜と
する (これら金属の金属塩、例えば、硫酸塩、炭酸塩、
酸化物、水酸化物を複合皮膜へのこれら金属化合物の含
有量を金属元素に換算して1.0 at% 以上含有させる) 。
或いは、Alの自然電位よりも電位的に卑な金属化合物で
あるSi、Mnなどの金属化合物を、総和でかつ皮膜中の平
均含有量で1at%以上含む複合乃至混合皮膜とする (これ
ら金属の金属塩、例えば、硫酸塩、炭酸塩、酸化物、水
酸化物を複合皮膜へのこれら金属化合物の含有量を金属
元素に換算して1.0 at% 以上含有させる) 。これらの場
合には、Alの水和酸化物単味の皮膜の場合に比して、耐
水性や耐糸さび性、更には全面腐食などの耐食性がより
優れる。但し、これら金属化合物或いは不純物元素など
の許容量は、Alの水和酸化物皮膜の耐食性や密着性など
の特性を阻害しない範囲とする。
For example, a hydrated oxide of Al, Fe, Ni, Co,
A composite film with one or more metal compounds selected from Zn (metal salts of these metals, for example, sulfates, carbonates,
Oxides and hydroxides are contained in the composite film in an amount of at least 1.0 at% in terms of the metal element in terms of the metal element).
Alternatively, a composite or mixed film containing a metal compound such as Si or Mn, which is a metal compound that is lower in potential than the natural potential of Al, in a total amount and an average content in the film of 1 at% or more (these metal materials). Metal salts such as sulfates, carbonates, oxides, and hydroxides are contained in the composite coating in an amount of 1.0 at% or more in terms of the metal element in terms of the metal element). In these cases, the water resistance, the thread rust resistance, and the corrosion resistance such as overall corrosion are more excellent than the case of a film of a hydrated oxide of Al alone. However, the permissible amounts of these metal compounds or impurity elements are within a range that does not impair the properties such as corrosion resistance and adhesion of the hydrated oxide film of Al.

【0030】(Alの水和酸化物皮膜の膜厚)Alの水和酸化
物皮膜の膜厚は、耐粒界腐食性に対する前記絶縁効果発
揮のために必要な膜厚下限と、鋳鍛材や塗装皮膜との密
着性を阻害しない膜厚上限という点から決定される。Al
の水和酸化物皮膜の膜厚が100 Å未満であれば、前記塩
水腐食環境下と、Cu含有による鋳鍛材の粒界腐食感受性
の増大との相乗作用に対し、鋳鍛材の耐粒界腐食性を向
上させる効果が期待できない。一方、Alの水和酸化物皮
膜の膜厚が8000Åを越えた場合、皮膜の鋳鍛材や塗装皮
膜との密着性が低下して、皮膜や塗膜の剥離が生じ、結
果として、鋳鍛材の耐粒界腐食性を向上させられなくな
る。したがって、Alの水和酸化物皮膜の膜厚は100 〜80
00Å( オングストローム) の範囲とする。
(Film thickness of hydrated oxide film of Al) The film thickness of the hydrated oxide film of Al is determined by the lower limit of the film thickness necessary for exhibiting the insulating effect on intergranular corrosion resistance, And the upper limit of the film thickness which does not hinder the adhesion to the coating film. Al
If the thickness of the hydrated oxide film is less than 100 mm, the forging resistance of the cast forging material is reduced by the synergistic effect of the salt water corrosion environment and the increase in intergranular corrosion susceptibility of the casting and forging material due to the inclusion of Cu. The effect of improving interfacial corrosion cannot be expected. On the other hand, if the film thickness of the hydrated oxide film of Al exceeds 8000 mm, the adhesion of the film to the cast and forged material or the paint film is reduced, and the film or the paint film is peeled off. The grain boundary corrosion resistance of the material cannot be improved. Therefore, the thickness of the hydrated oxide film of Al is 100-80.
The range is 00Å (angstrom).

【0031】(Alの水和酸化物皮膜の形成)Al合金鋳鍛材
表面に、Alの水和酸化物皮膜を形成する段階は、Al合金
鋳鍛材を構造材に加工する際に、加工によって皮膜が損
傷を受ける可能性がある場合には、加工後に皮膜を形成
することが望ましい。
(Formation of Al Oxide Oxide Film) The step of forming the Al hydrate oxide film on the surface of the Al alloy cast and forged material is performed when the Al alloy cast and forged material is processed into a structural material. When there is a possibility that the film may be damaged by the process, it is desirable to form the film after processing.

【0032】Alの水和酸化物皮膜の形成方法は、Al合金
鋳鍛材 (構造材) を、脱脂、洗浄等の前処理の後に、Al
合金材表面を、高温水や水蒸気に直接接触させる方法、
あるいはAl合金材表面にAlの酸化物層を設けた後で水和
反応によりAlの水和酸化物皮膜に変換する方法、更に、
これらAlの水和酸化物皮膜を設けた後に、加熱により水
和量を調節する方法、あるいは前記特開平05-70969号公
報などのような、高温の中性または弱アルカリ性浴( 純
水、水道水、トリエタノールアミンやアンモニアの水溶
液) に接触させる方法等を適宜選択して、Alの水和酸化
物皮膜を作成する。
The method for forming the hydrated oxide film of Al is as follows. The pretreatment such as degreasing and cleaning is performed on the cast aluminum forging (structural material).
A method in which the surface of the alloy material is brought into direct contact with high-temperature water or steam,
Alternatively, a method of converting to an Al hydrated oxide film by a hydration reaction after providing an Al oxide layer on the Al alloy material surface,
After providing these hydrated oxide films of Al, a method of adjusting the hydration amount by heating, or a high-temperature neutral or weak alkaline bath (pure water, tap water) as described in JP-A-05-70969, etc. Water or an aqueous solution of triethanolamine or ammonia) is appropriately selected to form a hydrated oxide film of Al.

【0033】そして、これらAlの水和酸化物皮膜を設け
たAl合金鋳鍛材は、基本的に無塗装で、構造材として使
用可能である。ただ、他の部材との関係、或いは輸送機
用構造材としての美観や意匠性を向上させるために、更
には、前記塩水腐食環境下での耐食性を向上させるため
に、Alの水和酸化物皮膜の上に、更に、通常の塗装が施
されてされてよい。
The Al alloy casting and forging provided with the hydrated oxide film of Al is basically unpainted and can be used as a structural material. However, in order to improve the relationship with other members or the appearance and design as a structural material for a transport aircraft, and further, to improve the corrosion resistance under the salt water corrosion environment, a hydrated oxide of Al is used. A normal coating may be further applied on the film.

【0034】(塗装)なお、塗装の際には、Alの水和酸化
物皮膜を設けたAl合金鋳鍛材表面が、極端なアルカリ性
や酸性とならず、中性範囲となるような塗装乃至塗装下
地処理を行うことが好ましい。この点、具体的には、静
電塗装、アニオン電着塗装およびスプレー塗装、ロール
コーター塗装、浸漬塗装から選択された非カチオン電着
塗装による塗装を選択的に行う。
(Coating) In the coating, the surface of the Al alloy cast and forged material provided with the hydrated oxide film of Al is not excessively alkaline or acidic and has a neutral range. It is preferable to perform a coating base treatment. In this regard, specifically, non-cationic electrodeposition coating selected from electrostatic coating, anion electrodeposition coating and spray coating, roll coater coating, and dip coating is selectively performed.

【0035】これに対し、例えば、Alの水和酸化物皮膜
を設けたAl合金鋳鍛材に、カチオン電着塗装等のAl合金
を陰極とした電気化学的な反応による塗装を施すと、生
成したアルカリ物質により、水和酸化物皮膜が部分的に
溶解や割れを生じるようなダメージを与え、却って、耐
粒界腐食性が劣化する可能性がある。これは、強酸性の
リン酸塩処理のような塗装下地処理の場合も同様であ
る。
On the other hand, for example, when an Al alloy casting and forging provided with a hydrated oxide film of Al is coated by an electrochemical reaction using an Al alloy as a cathode, such as a cation electrodeposition coating, the formation is produced. There is a possibility that the hydrated oxide film may be partially damaged or damaged by the alkali substance, and the intergranular corrosion resistance may be deteriorated. This is the same in the case of a paint base treatment such as a strongly acidic phosphate treatment.

【0036】(適用対象Al合金)次に、本発明の適用対象
Al合金は、構造材としての要求を満足するために、Cu:
0.05%以上を含み、鍛造材としては、人工時効硬化処
理後の耐力 (σ0.2)の平均値が280N/mm2以上およびシャ
ルピー衝撃値の平均値が20J/cm2 以上であることが好ま
しい (請求項2 に対応) 。また、鋳造材としては、人
工時効硬化処理後の耐力 (σ0.2)が230N/mm2以上、シャ
ルピー衝撃値が12/cm2以上、および伸びが18% 以上であ
ることが好ましい (請求項4 に対応) 。
(Applicable Al alloy) Next, the applicable object of the present invention
Al alloy, to satisfy the requirements as a structural material, Cu:
Including 0.05% or more, as a forged material, it is preferable that the average value of proof stress (σ 0.2 ) after artificial age hardening treatment is 280 N / mm 2 or more and the average value of Charpy impact value is 20 J / cm 2 or more ( (Corresponds to claim 2). Further, as the cast material, it is preferable that the yield strength after artificial age hardening (σ 0.2 ) is 230 N / mm 2 or more, the Charpy impact value is 12 / cm 2 or more, and the elongation is 18% or more. Corresponding).

【0037】この特性を満足するために、鍛造材とし
ては、強度や靱性が高く、時効硬化性やリサイクル性に
優れたAl-Si-Mg系 Al 合金として、 Mg:0.6 〜1.6% (質
量%、以下同じ) 、Si:0.8〜1.8%を含む、AA乃至JIS 61
01 、6003、6151、6061、6N01、6063などの6000系Al合
金が好ましい (請求項3 に対応) 。ただ、前記要求特性
を満足できるものであれば、5000系、7000系などのAl合
金も適宜使用可能である。
In order to satisfy this property, as a forged material, an Al-Si-Mg-based Al alloy having high strength and toughness, and excellent in age hardenability and recyclability, has a Mg content of 0.6 to 1.6% (mass%). , The same applies hereinafter), Si: containing 0.8 to 1.8%, AA to JIS 61
Preferred are 6000 series Al alloys such as 01, 6003, 6151, 6061, 6N01, and 6063 (corresponding to claim 3). However, aluminum alloys such as 5000 series and 7000 series can be appropriately used as long as the required characteristics can be satisfied.

【0038】また、鋳造材としては、強度や靱性が高
く、鋳造性も良好である、Siを2.0%(質量% 、以下同じ)
以上含み、高圧鋳造法により鋳込まれ、溶体化処理お
よび人工時効硬化処理が施されたAA乃至JIS AC4CH など
の Al-Si-Mg 系鋳造用Al合金が好ましい (請求項5 に対
応) 。ただ、前記要求特性を満足できるものであれば、
JIS AC1 〜AC9 、ADC1〜14までのAl合金も適宜使用可能
である。より具体的には、Al-Cu 系のAC1A、AC1B、Al-C
u-Si系のAC2A、AC2B、Al-Si 系のAC3A、Al-Si-Mg系のAC
4A、AC4C、AC4CH 、Al-Si-Cu系のAC4B、Al-Si-Cu-Mg 系
のAC4D、Al-Cu-Ni-Mg 系のAC5A、Al-Mg 系のAC7A、Al-S
i-Ni-Cu-Mg系のAC8A、AC8B、AC8C、Al-Si-Cu-Mg-Ni系の
AC9A、AC9B等のAl合金が使用可能である。
As the casting material, 2.0% (mass%, hereinafter the same) of Si, which has high strength and toughness and good castability, is used.
It is preferable to use an Al-Si-Mg-based casting Al alloy such as AA to JIS AC4CH, which includes the above, is cast by a high-pressure casting method, and is subjected to a solution treatment and an artificial age hardening treatment (corresponding to claim 5). However, if the required characteristics can be satisfied,
Al alloys of JIS AC1 to AC9 and ADC1 to ADC14 can also be used as appropriate. More specifically, Al-Cu based AC1A, AC1B, Al-C
u-Si AC2A, AC2B, Al-Si AC3A, Al-Si-Mg AC
4A, AC4C, AC4CH, Al-Si-Cu-based AC4B, Al-Si-Cu-Mg-based AC4D, Al-Cu-Ni-Mg-based AC5A, Al-Mg-based AC7A, Al-S
i-Ni-Cu-Mg based AC8A, AC8B, AC8C, Al-Si-Cu-Mg-Ni based
Al alloys such as AC9A and AC9B can be used.

【0039】しかし、鋳鍛材が、各成分規格通りになら
ずとも、前記基本的な特性を有してさえいれば、更なる
特性の向上や他の特性を付加するための、適宜成分組成
の変更は許容される。この点、上記元素の成分範囲の変
更や、より具体的な用途および要求特性に応じて、Zn、
Ti、B 、Be、Mn、Cr、Zr、V 等他の元素を適宜含むこと
は許容される。また、これら元素を含め、不純物量とし
ては、JIS 規格での上限レベルまでの含有は許容され
る。更に、H2やO2などのガス成分や溶解原料スクラップ
などから必然的に混入される不純物も、本発明鍛造材の
品質を阻害しない範囲で許容される。
However, as long as the cast forging material does not conform to the respective component specifications and has the above-mentioned basic characteristics, the component composition for further improving the characteristics and adding other characteristics is appropriately determined. Changes are allowed. In this regard, according to changes in the component ranges of the above elements, and more specific applications and required characteristics, Zn,
It is permissible to appropriately contain other elements such as Ti, B, Be, Mn, Cr, Zr, and V. The content of impurities including these elements up to the upper limit level in the JIS standard is allowable. Further, impurities inevitably mixed in from gas components such as H 2 and O 2 and scraps of dissolved raw materials are allowed as long as the quality of the forged material of the present invention is not impaired.

【0040】(鍛造材の製造方法)次に、本発明鋳鍛材の
内のAl合金鍛造材の好ましい製造方法について述べる。
本発明におけるAl合金鍛造材の製造自体は常法により製
造が可能である。例えば、前記Al合金成分範囲内に溶解
調整されたAl合金溶湯を鋳造する場合には、例えば、連
続鋳造圧延法、半連続鋳造法(DC鋳造法)、ホットト
ップ鋳造法等の通常の溶解鋳造法を適宜選択して鋳造す
る。
(Method of Manufacturing Forged Material) Next, a preferred method of manufacturing an Al alloy forged material of the cast forged material of the present invention will be described.
The production of the forged Al alloy in the present invention itself can be carried out by an ordinary method. For example, when casting an Al alloy melt that has been melt-adjusted within the range of the above-mentioned Al alloy components, for example, a normal melt casting such as a continuous casting rolling method, a semi-continuous casting method (DC casting method), and a hot top casting method. Casting is performed by appropriately selecting a method.

【0041】しかし、Al合金鍛造材の靱性向上のため
に、Al合金鋳造材の結晶粒を微細化させる、およひ前記
Mg2Si とAl-Fe-Si-(Mn、Cr、Zr) 系晶出物の合計の面積
率を低くするためにはAl合金溶湯を、10℃/sec以上の冷
却速度で鋳造して鋳塊とすることが好ましい。
However, in order to improve the toughness of the forged Al alloy, the crystal grains of the cast Al alloy are refined.
In order to reduce the total area ratio of Mg 2 Si and Al-Fe-Si- (Mn, Cr, Zr) crystallized materials, cast an Al alloy melt at a cooling rate of 10 ° C / sec or more. Preferably, it is a lump.

【0042】次いで、このAl合金鋳塊 (鋳造材) を均質
化熱処理する際、通常の均質化熱処理 (470 〜480 ℃)
でよい。ただ、Mn、Cr、Zrの一種または二種以上を含有
させて、均質化熱処理時に、Al20Cu2Mn3、Al12Mg2Cr 、
Al3Zr などの分散粒子 (分散相) を生成して、微細な結
晶粒を得るためには500 ℃以上の温度で均質化熱処理す
ることが好ましい。
Next, when the Al alloy ingot (cast material) is subjected to a homogenizing heat treatment, a normal homogenizing heat treatment (470 to 480 ° C.) is performed.
Is fine. However, Mn, Cr, containing one or more of Zr, during the homogenization heat treatment, Al 20 Cu 2 Mn 3 , Al 12 Mg 2 Cr,
In order to generate dispersed particles (dispersed phase) such as Al 3 Zr and obtain fine crystal grains, it is preferable to perform a homogenizing heat treatment at a temperature of 500 ° C. or more.

【0043】この均質化熱処理の後に、メカニカル鍛造
や油圧鍛造等により熱間鍛造して、最終製品形状( ニア
ネットシェイプ) のAl合金鍛造材に成形する。そして、
鍛造後、必要な強度および靱性を得るためのT6処理 (溶
体化処理後焼入れ) などの調質熱処理および時効処理が
行われる。なお、Al合金鍛造材に残留する鋳造組織を無
くし、強度と靱性をより向上させるために、Al合金鋳造
材を均質化熱処理後、押出加工した後に、前記鍛造を行
っても良い。
After the homogenizing heat treatment, the forged material is subjected to hot forging by mechanical forging, hydraulic forging, or the like to form an Al alloy forged material having a final product shape (near net shape). And
After forging, heat treatment and aging treatment such as T6 treatment (hardening after solution treatment) to obtain necessary strength and toughness are performed. In addition, in order to eliminate the cast structure remaining in the Al alloy forged material and further improve strength and toughness, the Al alloy cast material may be subjected to homogenization heat treatment, extruded, and then subjected to the forging.

【0044】(鋳造材の製造方法)次に、鋳造材の好まし
い製造方法について述べる。本発明におけるAl合金鋳造
材の鋳造方法は、ダイカスト法、砂型鋳造法、金型鋳造
法などの方法ではなく、高圧鋳造法 (溶湯鍛造法) によ
り行うことが好ましい。高圧鋳造法では、空気の巻き込
み防止、空気や酸化物の巻き込み少、引け巣等の鋳造欠
陥の抑制、凝固結晶粒やデンドライト二次アーム間隔(D
AS) の微細化等により、鋳造欠陥を抑制し、より高強度
で高靱性化した、信頼性の高いAl合金鋳造材を製造する
ことが可能となる。
(Manufacturing Method of Casting Material) Next, a preferred manufacturing method of the casting material will be described. The casting method of the Al alloy casting material in the present invention is preferably performed by a high-pressure casting method (a molten metal forging method), not by a method such as a die casting method, a sand casting method, or a die casting method. In the high-pressure casting method, prevention of air entrapment, suppression of air and oxide entrapment, suppression of casting defects such as shrinkage cavities, solidified crystal grains and dendrite secondary arm spacing (D
By miniaturization of AS), casting defects can be suppressed, and a higher strength and tougher Al alloy casting material with high reliability can be manufactured.

【0045】高圧鋳造法自体は、例えば、溶解炉から横
型乃至縦型のスリーブ内に、Al合金溶湯を給湯管などを
介して流し込み、その後スリーブ内のAl合金溶湯をピス
トンにより加圧して、Al合金溶湯をスリーブ内の金型に
接触させて冷却する方式が代表的な例である。
In the high-pressure casting method itself, for example, an Al alloy melt is poured from a melting furnace into a horizontal or vertical sleeve via a hot water supply pipe or the like, and thereafter, the Al alloy melt in the sleeve is pressurized by a piston to form an Al alloy. A typical example is a method in which a molten alloy is brought into contact with a mold in a sleeve and cooled.

【0046】高圧鋳造法により鋳込まれたAl合金材は、
T6などの溶体化処理後焼き入れを行い、人工時効硬化処
理を施して製造される。溶体化処理の際の温度は、Siや
Mgの固溶のための、通常の処理温度530 〜540 ℃の範囲
で良い。ただ、溶体化処理の時間は、共晶Siの粗大化の
防止のために、2 時間以内の短時間とする方が好まし
い。2 時間を越える溶体化処理では、前記共晶Siの最大
径の粗大化が生じ、構造材としての衝撃破壊強度が低下
する。
The Al alloy material cast by the high pressure casting method,
It is manufactured by performing quenching after solution treatment such as T6 and performing artificial age hardening treatment. The temperature during the solution treatment is Si or
The usual processing temperature for solid solution of Mg may be in the range of 530 to 540 ° C. However, the solution treatment time is preferably set to a short time of 2 hours or less in order to prevent eutectic Si from becoming coarse. If the solution treatment is performed for more than 2 hours, the maximum diameter of the eutectic Si becomes coarse, and the impact fracture strength as a structural material decreases.

【0047】[0047]

【実施例】次に、本発明の実施例を説明する。 (鋳造材)表1 に示す、AC4CH 規格内 (但し、Cuを0.20%
含む) のAl合金溶湯を、高圧鋳造法により、自動車サス
ペンション部品としての厚み6mm の薄肉のアーム類に鋳
造した (冷却速度20℃/sec) 。そして、鋳込まれた鋳造
材を、硝石炉を用いて、535 ℃×1 時間の溶体化処理後
焼き入れを行い、更に、160 ℃×5 時間の人工時効処理
(亜時効処理) を行った。
Next, embodiments of the present invention will be described. (Casting material) AC4CH standard shown in Table 1 (However, Cu is 0.20%
) Was cast by high-pressure casting into thin arms with a thickness of 6 mm as automotive suspension parts (cooling rate: 20 ° C / sec). Then, the cast material is quenched after solution treatment at 535 ° C for 1 hour using a nitrite furnace, and then artificial aging at 160 ° C for 5 hours.
(Sub-aging treatment).

【0048】(鍛造材)表1 に示す、6151、5454、7050規
格内(Cu を各々0.05% 以上含む) のAl合金鋳塊 (Al合金
鋳造材、いずれもφ68mm径×580mm 長さの丸棒) を、ホ
ットトップ鋳造法により溶製後 (冷却速度20℃/sec) 、
550 ℃×8 時間の均質化熱処理を施し、50〜75% の加工
率で、自動車サスペンション部品としての厚み6mm の薄
肉のアーム類に、メカニカル鍛造により、熱間鍛造し
た。次に、このAl合金鍛造材を硝石炉を用いて560 ℃で
1 時間の溶体化処理した後水冷 (水焼入れ) を行い、そ
の後180 ℃×5 時間の人工時効処理を行った。
(Forged material) An Al alloy ingot within the specifications of 6151, 5454, and 7050 (each containing 0.05% or more of Cu) shown in Table 1 (Al alloy cast material, all round bars of φ68 mm diameter × 580 mm length) ) After hot-top casting (cooling rate 20 ° C / sec)
A homogenizing heat treatment at 550 ° C for 8 hours was applied, and a thin forged arm with a thickness of 6 mm as an automobile suspension part was hot forged by mechanical forging at a processing rate of 50 to 75%. Next, the forged aluminum alloy was heated at 560 ° C. using a nitrite furnace.
After solution treatment for 1 hour, water cooling (water quenching) was performed, and then artificial aging treatment was performed at 180 ° C for 5 hours.

【0049】(Alの水和酸化物皮膜の形成)そして、これ
らAl合金鋳造材およびAl合金鍛造材に対し、洗浄後、各
々Alの水和酸化物皮膜を各々表1 に示す厚みで設けた
(発明例No.1〜8)。各例とも、Al合金材を40℃の30% 硝
酸に2 分間浸漬して水洗後、70〜90℃の0.5%トリエタノールアミン
(TEA) 水溶液中に3 〜10分浸漬してAlの水和酸化物皮膜
を形成するとともに、温度と浸漬時間を変えて、皮膜厚
みを制御した。
(Formation of hydrated oxide film of Al) Then, after washing these Al alloy cast material and Al alloy forged material, each hydrated oxide film of Al was provided with a thickness shown in Table 1.
(Invention Examples Nos. 1 to 8). In each case, the Al alloy material was immersed in 40% 30% nitric acid for 2 minutes, washed with water, and then 0.5% triethanolamine at 70-90 ° C.
(TEA) The hydrated oxide film of Al was formed by immersion in an aqueous solution for 3 to 10 minutes, and the film thickness was controlled by changing the temperature and the immersion time.

【0050】比較のために、Alの水和酸化物皮膜の膜厚
が薄すぎる比較例No.9、およびAlの水和酸化物皮膜の膜
厚が厚すぎる比較例No.10 、Alの水和酸化物皮膜の代わ
りにクロメート皮膜を設けた比較例No.11 、同じくZn置
換メッキ皮膜を設けた比較例No.12 も作製した。これら
Alの水和酸化物皮膜の膜厚を表2 に示す。なお、表2のA
l合金材のNo.A〜D は、表2 のAl合金材のNo.A〜D に各
々対応しており、A が鋳造材、それ以外は鍛造材であ
る。
For comparison, in Comparative Example No. 9 in which the thickness of the hydrated oxide film of Al was too thin, and in Comparative Example No. 10 in which the film thickness of the hydrated oxide film of Al was too thick, Comparative Example No. 11 in which a chromate film was provided instead of the oxidized oxide film, and Comparative Example No. 12 in which a Zn-substituted plated film was also provided. these
Table 2 shows the thickness of the hydrated oxide film of Al. In Table 2, A
The alloy materials Nos. A to D correspond to the Al alloy materials Nos. A to D in Table 2, respectively, where A is a cast material and the others are forged materials.

【0051】(Al の水和酸化物皮膜の同定)これらの各A
l合金材 (発明例No.1〜8 、比較例No.9、10) から試験
片を採取して、試験片のAlの水和酸化物皮膜をFT−IR法
により同定した結果、3000〜3700cm -1付近に認められる
AlO ←→H の伸縮振動による吸収スペクトル、および10
00〜1050cm-1付近に認められるAl←→OHの伸縮振動によ
る吸収スペクトル、更に800〜600cm -1付近に認められ
るOAl ←→O の伸縮振動による吸収スペクトルの少なく
とも1 つ以上が認められることにより、Alの水和酸化物
皮膜の存在が確認された。
(Identification of hydrated oxide film of Al)
l Tested from alloy material (Invention Nos. 1-8, Comparative Nos. 9 and 10)
Specimens were collected and the hydrated oxide film of Al on the test specimen was subjected to the FT-IR method
3,000-3700cm -1Admitted nearby
Absorption spectrum due to stretching vibration of AlO ← → H, and 10
00 ~ 1050cm-1Due to the stretching vibration of Al ← → OH
Absorption spectrum, further 800-600cm-1Recognized near
Absorption spectrum due to stretching vibration of OAl ← → O
Hydrated oxide of Al
The presence of a film was confirmed.

【0052】また、Al合金材試験片の180 °曲げを行っ
たAlの水和酸化物皮膜破面を50000倍 (膜厚の薄い例は1
50000倍) 倍の走査型電子顕微鏡(SEM) による観察した
結果、発明例No.1〜8 および比較例No.9、10は立て板状
の粗な上層皮膜と、粒状の緻密な下層皮膜とからなって
いることを確認した。更に、Alの水和酸化物皮膜の厚み
の測定も、このSEM による観察で行った。
Further, the fracture surface of the hydrated oxide film of Al obtained by bending the Al alloy material test piece by 180 ° was 50,000 times (the thin film was
As a result of observation with a scanning electron microscope (SEM) at a magnification of 50000 times, Invention Examples Nos. 1 to 8 and Comparative Examples Nos. 9 and 10 showed a vertical plate-like coarse upper film and a granular dense lower film. Confirmed that it consists of. Further, the measurement of the thickness of the hydrated oxide film of Al was also performed by observation with this SEM.

【0053】(塗装条件)更に、各Al合金材より選択的に
塗装後耐蝕性試験片を採取し、表面の潤滑剤を脱脂や洗
浄工程において完全に除去し、その後、発明例および比
較例とも、更に電気化学的反応を伴わないスプレー塗装
法にて2 コート2 ベーク塗装皮膜を設けた。なお、発明
例No.6のみは、リン酸亜鉛処理後に、電気化学的反応を
伴うカチオン電着塗装を行い、その後、他の発明例と同
様に塗装皮膜を設けた。
(Coating conditions) Further, a corrosion resistance test piece was sampled after coating selectively from each of the Al alloy materials, and the lubricant on the surface was completely removed in a degreasing and cleaning step. Then, a two-coat two-bake coating film was formed by a spray coating method without an electrochemical reaction. In addition, only the invention example No. 6 was subjected to cationic electrodeposition coating involving an electrochemical reaction after zinc phosphate treatment, and thereafter, a coating film was provided in the same manner as the other invention examples.

【0054】2 コート2 ベーク塗装として、より具体的
には、中塗り塗装として、30μm 厚さのポリエステルメ
ラミン系塗装皮膜を設けて、170 ℃×2 分の焼き付けを
行い、更に上塗り塗装として、30μm 厚さのポリエステ
ルメラミン系塗装皮膜を設けて、170 ℃×20分の焼き付
けを行った。
2 Coat 2 As a bake coating, more specifically, a 30 μm thick polyester melamine-based coating film was provided as an intermediate coating, baked at 170 ° C. for 2 minutes, and further overcoated with a 30 μm A thick polyester melamine coating film was provided and baked at 170 ° C. for 20 minutes.

【0055】(粒界腐食試験)これら発明例および比較例
の塗装および無塗装 Al 合金材より、試験片を採取し、
粒界腐食試験を行った。粒界腐食試験はJIS W 1103法の
4.4.3 項に記載の方法により行い、粒界腐食割れ性を評
価した。粒界腐食試験条件は、まず、93℃のエッチング
溶液(70%濃硝酸50ml、48% ふっ化水素酸5ml 、蒸留水94
5ml の組成)に1 分間浸漬後、蒸留水で洗浄し、乾燥さ
せた試験片を、U 字状に曲げて固定し、応力を負荷した
状態で、30℃の腐食促進液(NaCl57g、30% 過酸化水素水
10mlを蒸留水で1lに希釈したもの) に6 時間浸漬した。
そして、断面試験片 (試験片の断面) を、エッチング溶
液(70%濃硝酸2.5ml 、濃塩酸1.5ml 、48% ふっ化水素酸
1.0ml 、蒸留水95.0mlの組成) に10秒間浸漬後、蒸留水
で洗浄して乾燥し、200倍の金属顕微鏡により組織の腐
食状況を観察した。
(Granular intergranular corrosion test) Test specimens were taken from the painted and unpainted Al alloy materials of these invention examples and comparative examples.
An intergranular corrosion test was performed. The intergranular corrosion test is based on the JIS W 1103 method.
Grain boundary corrosion cracking was evaluated by the method described in Section 4.4.3. The conditions for the intergranular corrosion test were as follows: first, an etching solution at 93 ° C (50 ml of 70% concentrated nitric acid, 5 ml of 48% hydrofluoric acid, distilled water 94
After immersion in distilled water for 1 minute, the test piece washed with distilled water and dried was bent in a U-shape, fixed, and subjected to a stress while applying a corrosion promoting solution (NaCl 57 g, 30% Hydrogen peroxide solution
10 ml diluted to 1 l with distilled water) for 6 hours.
Then, the cross-section test piece (cross-section of the test piece) was placed in an etching solution (2.5 ml of 70% concentrated nitric acid, 1.5 ml of concentrated hydrochloric acid, 48% hydrofluoric acid).
1.0 ml, distilled water 95.0 ml) for 10 seconds, washed with distilled water, dried, and observed for the corrosion state of the tissue with a 200 × metal microscope.

【0056】粒界腐食の観察は、前記顕微鏡視野内にお
いて、他の孔食腐食や全面腐食などと区別して、結晶粒
界に沿って厚み方向に、表面から網目状乃至河口状に腐
食が進展している、典型的に粒界腐食と判断される腐食
点の数と粒界腐食の最大深さ(μm)を求め、顕微鏡視野
内において平均化し、粒界腐食性を評価した。これらの
結果も表2 に示す。
In the observation of grain boundary corrosion, the corrosion progresses in the thickness direction along the crystal grain boundaries and in the form of a mesh or estuary from the surface in the visual field of the microscope, in distinction from other pitting corrosion or general corrosion. The number of corrosion points, which are typically determined to be intergranular corrosion, and the maximum depth (μm) of intergranular corrosion were determined, averaged in a microscope visual field, and the intergranular corrosion was evaluated. Table 2 also shows these results.

【0057】(応力腐食割れ試験)また、同じく、発明例
および比較例の塗装および無塗装 Al 合金材より板状試
験片を採取し、応力腐食割れ試験を行った。応力腐食割
れ試験条件は、各試験片を、30% の加工率で冷間圧延
後、120 ℃×7 日間の熱処理を行う鋭敏化処理を施し、
鋭敏化試験片をR が14t のU 字に曲げて治具に取り付
け、試験片両端部を拘束した応力付加状態で、電流密度
0.062mA/mm2 で試験片に通電し、試験液に浸漬した。試
験液は、3.5%、30℃のNaCl水溶液とし、一定時間毎に試
験片の応力腐食割れ発生の有無を確認し、発生までの時
間 (分) により応力腐食割れを評価した。これらの結果
も表2 に示す。
(Stress Corrosion Cracking Test) Similarly, plate-like test pieces were sampled from the painted and unpainted Al alloy materials of the invention examples and comparative examples, and subjected to a stress corrosion cracking test. The stress corrosion cracking test conditions were as follows: each specimen was cold-rolled at a processing rate of 30%, and then subjected to a sensitization treatment of heat treatment at 120 ° C for 7 days.
The sensitized test piece was bent into a U-shape with R of 14t and attached to a jig.
The test piece was energized at 0.062 mA / mm 2 and immersed in the test solution. The test solution was a 3.5% NaCl aqueous solution at 30 ° C. The presence or absence of occurrence of stress corrosion cracking of the test piece was checked at regular intervals, and the stress corrosion cracking was evaluated based on the time (minutes) until the occurrence. Table 2 also shows these results.

【0058】(塗膜密着性試験)更に、同じく、発明例お
よび比較例の塗装 Al 合金材より試験片を採取し、40℃
のイオン交換水中に10日間浸漬し、浸漬後の塗膜に対
し、2mm 幅で10×10マスの碁盤目テープ剥離試験を 5回
行った。そして、5 回とも塗膜の剥離 (テープへの塗膜
の付着) が見られなかった例を○、1 回以上塗膜の剥離
が見られた例を×として評価した。これらの結果も表2
に示す。
(Coating film adhesion test) Further, similarly, test specimens were taken from the coated Al alloy materials of the invention examples and comparative examples,
Was immersed in ion-exchanged water for 10 days, and the coated film after the immersion was subjected to five times a 10 mm square cross-cut tape peeling test with a width of 2 mm. Then, an example in which no peeling of the coating film (adhesion of the coating film to the tape) was observed in all five times was evaluated as ○, and an example in which peeling of the coating film was observed one or more times was evaluated as ×. These results are also shown in Table 2.
Shown in

【0059】本発明のAl合金材表面にAlの水和酸化物皮
膜を設けた発明例No.1〜8 は、Cu:0.05%以上を含む鋳鍛
材であっても、無塗装材の試験片の表面の一部に、通常
の孔食腐食などが生じていたものの、表2 の結果から明
らかな通り、粒界腐食は生じていないか、生じていても
軽微であって、耐粒界腐食性に優れていることが分か
る。また、応力腐食割れの発生時間も1000分以上であ
り、応力腐食割れに対しても優れていることが分かる。
更に、塗装材については、塗膜の密着性も良好であっ
た。したがって、本発明のAl合金材は、クロメート皮膜
を設けた比較例No.11と同等の耐食性を有していること
が分かる。
The invention examples Nos. 1 to 8 of the present invention in which an Al hydrated oxide film was provided on the surface of the Al alloy material were tested for an unpainted material even if the cast and forged material contained Cu: 0.05% or more. Although normal pitting corrosion etc. occurred on a part of the surface of the piece, as evident from the results in Table 2, grain boundary corrosion did not occur, or even if it occurred, it was slight It turns out that it is excellent in corrosiveness. In addition, the time of occurrence of stress corrosion cracking was 1000 minutes or more, which indicates that stress corrosion cracking is excellent.
Further, with respect to the coating material, the adhesion of the coating film was also good. Therefore, it can be seen that the Al alloy material of the present invention has the same corrosion resistance as Comparative Example No. 11 provided with a chromate film.

【0060】ただ、Alの水和酸化物皮膜の膜厚が比較的
薄い発明例No.5、リン酸亜鉛処理およびカチオン電着塗
装によって、Alの水和酸化物皮膜が劣化した発明例No.6
のみは、ため、と同様に塗装皮膜を設けた。
However, Invention Example No. 5 in which the thickness of the hydrated oxide film of Al was relatively thin, and Invention Example No. 5 in which the hydrated oxide film of Al was deteriorated by zinc phosphate treatment and cationic electrodeposition coating. 6
Only, a coating film was provided in the same manner as described above.

【0061】一方、これに対し、Alの水和酸化物皮膜の
膜厚が薄すぎる比較例No.9、およびAlの水和酸化物皮膜
の膜厚が厚すぎる比較例No.10 、Alの水和酸化物皮膜の
代わりにZn置換メッキ皮膜を設けた比較例No.12 は、粒
界腐食が生じやすく、また、応力腐食割れ性も劣り、更
に、塗膜の密着性も劣っている。
On the other hand, in Comparative Example No. 9 in which the thickness of the hydrated oxide film of Al was too thin, and in Comparative Example No. 10 in which the thickness of the hydrated oxide film of Al was too thick, In Comparative Example No. 12, in which a Zn-substituted plating film was provided instead of the hydrated oxide film, intergranular corrosion easily occurred, stress corrosion cracking was poor, and adhesion of the coating was poor.

【0062】したがって、以上の事実から、本発明規定
の臨界的な意義や好ましい条件の意義が裏付けられる。
Accordingly, the above facts support the critical significance and preferred conditions of the present invention.

【0063】[0063]

【表1】 [Table 1]

【0064】[0064]

【表2】 [Table 2]

【0065】[0065]

【発明の効果】本発明によれば、Cu添加を添加しても、
耐粒界腐食性や耐応力腐食性等の耐食性を向上させた、
構造材用Al合金鋳鍛材を提供することができる。したが
って、Al合金材の機能を向上させるとともに、用途を拡
げることができる点で、多大な工業的価値を有するもの
である。
According to the present invention, even when Cu is added,
Improved corrosion resistance such as intergranular corrosion resistance and stress corrosion resistance,
An aluminum alloy cast and forged material for a structural material can be provided. Therefore, it has a great industrial value in that the function of the Al alloy material can be improved and its use can be expanded.

フロントページの続き (51)Int.Cl.7 識別記号 FI テーマコート゛(参考) C23C 28/00 C23C 28/00 C // C22F 1/00 630 C22F 1/00 630B 640 640A Continued on the front page (51) Int.Cl. 7 Identification symbol FI Theme coat II (reference) C23C 28/00 C23C 28/00 C // C22F 1/00 630 C22F 1/00 630B 640 640A

Claims (7)

【特許請求の範囲】[Claims] 【請求項1】 Cu:0.05%以上を含み、構造材に用いるア
ルミニウム合金鋳鍛材であって、鋳鍛材表面に、膜厚が
100 〜8000Å (オングストローム) のアルミニウムの水
和酸化物皮膜を設けたことを特徴とする耐粒界腐食性に
優れたアルミニウム合金鋳鍛材。
1. An aluminum alloy cast and forged material containing Cu: 0.05% or more and used as a structural material, wherein a film thickness is formed on the surface of the cast and forged material.
An aluminum alloy cast and forged material with excellent intergranular corrosion resistance characterized by having a hydrated oxide film of aluminum of 100 to 8000 mm (angstrom).
【請求項2】 前記アルミニウム合金鋳鍛材が、Mg:0.6
〜1.6% (質量% 、以下同じ) 、Si:0.8〜1.8%を含むAl-M
g-Si系アルミニウム合金鍛造材である請求項1に記載の
耐粒界腐食性に優れたアルミニウム合金鋳鍛材。
2. The method according to claim 1, wherein the cast aluminum alloy has a Mg: 0.6
~ 1.6% (mass%, the same applies hereinafter), Si: 0.8-1.8% Al-M
The cast aluminum alloy forging according to claim 1, which is a g-Si based aluminum alloy forging.
【請求項3】 前記アルミニウム合金鍛造材の人工時効
硬化処理後の耐力 (σ0.2)の平均値が280N/mm2以上およ
びシャルピー衝撃値の平均値が20J/cm2 以上である請求
項2に記載の耐粒界腐食性に優れたアルミニウム合金鋳
鍛材。
3. The aluminum alloy forged material according to claim 2, wherein an average value of proof stress (σ 0.2 ) after artificial age hardening treatment is 280 N / mm 2 or more and an average value of Charpy impact value is 20 J / cm 2 or more. An aluminum alloy cast and forged material with excellent intergranular corrosion resistance as described.
【請求項4】 前記アルミニウム合金鋳鍛材が、Siを2.
0% (質量% 、以下同じ) 以上含み、高圧鋳造法により鋳
込まれ、溶体化処理および人工時効硬化処理が施された
アルミニウム合金鋳造材である請求項1に記載の耐粒界
腐食性に優れたアルミニウム合金鋳鍛材。
4. The method according to claim 1, wherein the aluminum alloy casting and forging material contains Si in an amount of 2.
An aluminum alloy cast material containing at least 0% (mass%, hereinafter the same), cast by a high pressure casting method, and subjected to a solution treatment and an artificial age hardening treatment. Excellent aluminum alloy casting and forging.
【請求項5】 前記アルミニウム合金鋳造材の人工時効
硬化処理後の耐力 (σ0.2)が230N/mm2以上、シャルピー
衝撃値が12/cm2以上、および伸びが18% 以上である請求
項4に記載の耐粒界腐食性に優れたアルミニウム合金鋳
鍛材。
5. The proof stress (σ 0.2 ) of the cast aluminum alloy material after artificial age hardening is 230 N / mm 2 or more, the Charpy impact value is 12 / cm 2 or more, and the elongation is 18% or more. An aluminum alloy cast and forged material having excellent intergranular corrosion resistance as described in 1.
【請求項6】 前記Al合金鋳鍛材が、輸送機の構造材用
である請求項1乃至5のいずれか1項に記載の耐粒界腐
食性に優れたアルミニウム合金鋳鍛材。
6. The aluminum alloy casting and forging having excellent grain boundary corrosion resistance according to claim 1, wherein the aluminum alloy forging is used for a structural material of a transport machine.
【請求項7】 前記輸送機が自動車用である請求項6に
記載の耐粒界腐食性に優れたアルミニウム合金鋳鍛材。
7. The aluminum alloy cast and forged material having excellent intergranular corrosion resistance according to claim 6, wherein the transporter is for an automobile.
JP19346899A 1999-07-07 1999-07-07 Aluminum alloy cast and forged material excellent in grain boundary corrosion resistance Pending JP2001020028A (en)

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Application Number Priority Date Filing Date Title
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Publication Number Publication Date
JP2001020028A true JP2001020028A (en) 2001-01-23

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US7883591B2 (en) 2004-10-05 2011-02-08 Aleris Aluminum Koblenz Gmbh High-strength, high toughness Al-Zn alloy product and method for producing such product
US8002913B2 (en) 2006-07-07 2011-08-23 Aleris Aluminum Koblenz Gmbh AA7000-series aluminum alloy products and a method of manufacturing thereof
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US8608876B2 (en) 2006-07-07 2013-12-17 Aleris Aluminum Koblenz Gmbh AA7000-series aluminum alloy products and a method of manufacturing thereof
US10472707B2 (en) 2003-04-10 2019-11-12 Aleris Rolled Products Germany Gmbh Al—Zn—Mg—Cu alloy with improved damage tolerance-strength combination properties
CN114008235A (en) * 2020-02-05 2022-02-01 学校法人芝浦工业大学 Fastening member and method for manufacturing same
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CN115928074A (en) * 2022-12-12 2023-04-07 昆明理工大学 Al-Mg-Si alloy grain boundary corrosion solution

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10472707B2 (en) 2003-04-10 2019-11-12 Aleris Rolled Products Germany Gmbh Al—Zn—Mg—Cu alloy with improved damage tolerance-strength combination properties
US7883591B2 (en) 2004-10-05 2011-02-08 Aleris Aluminum Koblenz Gmbh High-strength, high toughness Al-Zn alloy product and method for producing such product
US8002913B2 (en) 2006-07-07 2011-08-23 Aleris Aluminum Koblenz Gmbh AA7000-series aluminum alloy products and a method of manufacturing thereof
US8088234B2 (en) 2006-07-07 2012-01-03 Aleris Aluminum Koblenz Gmbh AA2000-series aluminum alloy products and a method of manufacturing thereof
US8608876B2 (en) 2006-07-07 2013-12-17 Aleris Aluminum Koblenz Gmbh AA7000-series aluminum alloy products and a method of manufacturing thereof
CN103031470A (en) * 2012-12-13 2013-04-10 湖南晟通科技集团有限公司 Aluminum alloy and casting method thereof, and method for extruding profile
CN114008235A (en) * 2020-02-05 2022-02-01 学校法人芝浦工业大学 Fastening member and method for manufacturing same
CN115772601A (en) * 2022-11-30 2023-03-10 立中四通轻合金集团股份有限公司 Aluminum-based intermediate alloy second-phase particle extracting agent and method for obtaining second-phase particles
CN115928074A (en) * 2022-12-12 2023-04-07 昆明理工大学 Al-Mg-Si alloy grain boundary corrosion solution

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