JP2001294956A - Free cutting brass excellent in dezincification resistance and its producing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide brass having a excellent dezincification resistance and machinability, easy to be hot worked, excellent in recycling properties and further advantageous in cost, and to provide its producing method. SOLUTION: This brass has a composition containing 60 to 63.0% Cu, 2.0 to 3.7% Pb, 0.02 to 0.07% P, 0.20 to 0.50% Sn and 0.10 to 0.20% Fe, and the residual Zn with inevitable impurities. The brass is compassed of structure of an α phase and a β phase, and the the β phase is divided by the α phase. The brass is produced by subjecting the ingot of a copper alloy having the above composition to extrusion or extrusion/drawing, and thereafter performing annealing at 350 to 550 deg.C.

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、耐脱亜鉛腐食性と
切削性に優れ、さらにリサイクル性にも優れた黄銅およ
びその製造方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to brass which is excellent in dezincification corrosion resistance and machinability, and is also excellent in recyclability, and a method for producing the same.

【０００２】[0002]

【従来の技術】従来、Ｃｕ−Ｚｎ合金にＰｂを添加した
黄銅は、鋳造性、熱間および冷間加工性、機械加工性に
優れているため、水栓金具、バルブ部品などとして使用
されているが、腐食性の水質環境下あるいは温水の下で
使用すると、亜鉛が選択的に溶出する脱亜鉛腐食を起こ
すという問題がある。2. Description of the Related Art Conventionally, brass obtained by adding Pb to a Cu--Zn alloy is excellent in castability, hot and cold workability, and machinability, and thus has been used as a faucet fitting, a valve part and the like. However, when used in a corrosive water environment or hot water, there is a problem in that zinc is eluted selectively to cause dezincification corrosion.

【０００３】Ｃｕ含有量の高いα黄銅においては、Ａ
ｓ、Ｐ、Ｓｂなどを添加することにより脱亜鉛腐食を防
止することができるが、α黄銅は理論上６７．５％以上
のＣｕを含有し、α＋β黄銅に比較して溶解温度が高
く、且つ熱間加工時の変形抵抗が大きいため、熱間加工
温度を高くしなければならず、従ってエネルギーコスト
が高くなり、また、α黄銅は機械加工時に切削屑が長く
つながる傾向があるから、自動旋盤加工に適さないとい
う難点がある。In α brass having a high Cu content, A
By adding s, P, Sb, etc., dezincification corrosion can be prevented. However, α brass contains 67.5% or more of Cu in theory, has a higher melting temperature than α + β brass, and Since the deformation resistance during hot working is large, the hot working temperature must be raised, which increases the energy cost.Also, α brass tends to lead to long cuttings during machining, so automatic lathes There is a disadvantage that it is not suitable for processing.

【０００４】ある一定量のＣｕ（５４．５〜６７．５％
Ｃｕ）を含有するα＋β黄銅は、α相中にβ相を均一に
分散させることにより、機械加工時の切削屑が細かく分
断され、また熱間加工時の変形抵抗も著しく低減される
が、α黄銅において脱亜鉛腐食防止に効果のあるＡｓ、
Ｐ、Ｓｂを添加してもβ相の脱亜鉛腐食を抑制すること
ができない。そのために、α＋β黄銅のうち、６１〜６
７．５％のＣｕを含むものは、適当な熱処理を施すこと
によりα黄銅に変態させることができることに着目し、
まずα＋β黄銅にＡｓ、Ｐ、Ｓｂを添加し、熱処理によ
りα黄銅に変態させることによって耐脱亜鉛腐食性を高
める手法が提案されている。しかしながら、マトリック
ス組織中のβ相の割合が多い場合には、β相が長手方向
に連続して連なっているため、α組織に変態させるため
の熱処理に長時間を要するという問題がある。A certain amount of Cu (54.5 to 67.5%
In the case of α + β brass containing Cu), by uniformly dispersing the β phase in the α phase, cutting chips at the time of machining are finely divided and deformation resistance at the time of hot working is significantly reduced. As which is effective in preventing dezincification corrosion in brass,
Even if P and Sb are added, the dezincification corrosion of the β phase cannot be suppressed. Therefore, among the α + β brass, 61 to 6
Focusing on those containing 7.5% Cu, they can be transformed into α-brass by performing an appropriate heat treatment.
First, a method has been proposed in which As, P, and Sb are added to α + β brass, and the dezincification corrosion resistance is increased by transforming the brass into α brass by heat treatment. However, when the ratio of the β phase in the matrix structure is large, the heat treatment for transforming into the α structure requires a long time because the β phase is continuously connected in the longitudinal direction.

【０００５】このような問題を改善し、耐脱亜鉛腐食性
と快削性をそなえ、熱間加工も容易な黄銅として、Ｃ
ｕ：６０．０〜６３．０％、Ｐｂ：２．０〜３．７％、
Ｐ：０．０２〜０．０６％を含有し、残部Ｚｎおよび不
可避不純物からなるα＋β黄銅も提案されている（特公
昭６３−９５７３号公報）が、この黄銅は、黄銅のスク
ラップに不可避的に含まれているＳｎおよびＦｅについ
ては、不純物としていずれも０．１％以下に限定され、
且つＳｎ、Ｆｅを含む不純物の合計量も０．２％以下に
制限されているため、製造時のスクラップ使用量が制限
され、コスト面で不利となる難点がある。[0005] As a brass capable of solving such problems, having anti-zinc corrosion resistance and free-cutting properties, and easy to hot work, C
u: 60.0 to 63.0%, Pb: 2.0 to 3.7%,
Although α + β brass containing 0.02 to 0.06% of P and the balance of Zn and unavoidable impurities has been proposed (Japanese Patent Publication No. 63-9573), this brass is inevitably used in scrap of brass. Regarding Sn and Fe contained, both are limited to 0.1% or less as impurities.
In addition, since the total amount of impurities including Sn and Fe is also limited to 0.2% or less, the amount of scrap used at the time of manufacturing is limited, which is disadvantageous in terms of cost.

【０００６】[0006]

【発明が解決しようとする課題】本発明は、Ｐｂ含有黄
銅における上記従来の問題点を解消するために、黄銅の
リターンスクラップに不可避的に含まれるＳｎ、Ｆｅを
必須成分とする黄銅の組成および組織の組合わせと耐脱
亜鉛腐食性など各種特性との関連について、試験、検討
を重ねた結果としてなされたものであり、その目的は、
優れた耐脱亜鉛腐食性と切削性をそなえ、熱間加工が容
易で、且つリサイクル性にも優れ、コスト的にも有利な
黄銅およびその製造方法を提供することにある。SUMMARY OF THE INVENTION In order to solve the above-mentioned conventional problems in Pb-containing brass, the present invention provides a composition of brass containing Sn and Fe inevitably contained in a brass return scrap as essential components. It was made as a result of repeated tests and examinations on the relationship between the combination of tissues and various properties such as dezincification corrosion resistance.
An object of the present invention is to provide a brass having excellent dezincification corrosion resistance and machinability, easy to hot work, excellent in recyclability, and advantageous in cost, and a method for producing the same.

【０００７】[0007]

【課題を解決するための手段】上記の目的を達成するた
めの本発明の請求項１による耐脱亜鉛腐食性に優れた快
削黄銅は、Ｃｕ：６０．０〜６３．０％、Ｐｂ：２．０
〜３．７％、Ｐ：０．０２〜０．０７％、Ｓｎ：０．２
０〜０．５０％、Ｆｅ：０．１０〜０．２０％を含有
し、残部Ｚｎおよび不可避不純物からなる組成を有し、
α相とβ相の２相からなり且つβ相がα相で分断されて
いる組織を有することを特徴とする。In order to achieve the above object, a free-cutting brass excellent in dezincification corrosion resistance according to claim 1 of the present invention is Cu: 60.0 to 63.0%, Pb: 2.0
To 3.7%, P: 0.02 to 0.07%, Sn: 0.2
0-0.50%, Fe: 0.10-0.20%, having a composition consisting of the balance Zn and unavoidable impurities,
It is characterized by having a structure composed of two phases, α phase and β phase, wherein β phase is separated by α phase.

【０００８】本発明の請求項２による耐脱亜鉛腐食性に
優れた快削黄銅の製造方法は、Ｃｕ：６０．０〜６３．
０％、Ｐｂ：２．０〜３．７％、Ｐ：０．０２〜０．０
７％、Ｓｎ：０．２０〜０．５０％、Ｆｅ：０．１０〜
０．２０％を含有し、残部Ｚｎおよび不可避不純物から
なる銅合金の鋳塊を、押出後、または押出および抽伸し
た後、３５０〜５５０℃の温度で焼鈍する工程を包含す
ることを特徴とする。According to a second aspect of the present invention, there is provided a method for producing free-cutting brass having excellent resistance to dezincification and corrosion.
0%, Pb: 2.0 to 3.7%, P: 0.02 to 0.0
7%, Sn: 0.20 to 0.50%, Fe: 0.10
A step of annealing a copper ingot containing 0.20%, the balance being Zn and unavoidable impurities, at a temperature of 350 to 550 ° C. after extrusion or after extrusion and drawing. .

【０００９】また、本発明の請求項３による耐脱亜鉛腐
食性に優れた快削黄銅の製造方法は、Ｃｕ：６０．０〜
６３．０％、Ｐｂ：２．０〜３．７％、Ｐ：０．０２〜
０．０７％、Ｓｎ：０．２０〜０．５０％、Ｆｅ：０．
１０〜０．２０％を含有し、残部Ｃｕおよび不可避不純
物からなる銅合金の鋳塊を押出後、１０℃／秒以下の冷
却速度で徐冷する工程を包含することを特徴とする。The method for producing free-cutting brass excellent in dezincification-corrosion resistance according to claim 3 of the present invention is characterized in that:
63.0%, Pb: 2.0-3.7%, P: 0.02-
0.07%, Sn: 0.20 to 0.50%, Fe: 0.
After extruding an ingot of a copper alloy containing 10 to 0.20%, the balance being Cu and unavoidable impurities, a step of gradually cooling at a cooling rate of 10 ° C./sec or less is included.

【００１０】[0010]

【発明の実施の形態】本発明における含有成分の意義お
よび限定理由について説明すると、Ｃｕは、Ｚｎより高
価であるから、その含有量を出来るだけ低減させること
が望ましく、その他の含有成分の影響を考慮し、いずれ
の温度範囲においてもα相とβ相の２相からなるマトリ
ックスが形成されるように、Ｃｕ：６３．０％以下とす
る。また、耐脱亜鉛腐食性と切削性を向上させるため
に、熱処理によりβ相を微細に分断させるには、熱間加
工後の状態でβ相存在率（α相＋β相中のβ相の割合）
を１／２以下にするのが好ましく、そのためにＣｕ：６
０．０％以上とする。さらに好ましいＣｕの含有量は６
１．０〜６２．０％の範囲である。BEST MODE FOR CARRYING OUT THE INVENTION Explaining the significance of the components contained in the present invention and the reasons for limitation, Cu is more expensive than Zn, so it is desirable to reduce its content as much as possible. Considering this, Cu is set to 63.0% or less so that a matrix composed of two phases of α phase and β phase is formed in any temperature range. Further, in order to improve the dezincification corrosion resistance and machinability, the β phase is finely divided by heat treatment, and the β phase abundance (% of β phase in α phase + β phase) in the state after hot working )
Is preferably １ ／ or less, and therefore Cu: 6
0.0% or more. More preferred Cu content is 6
It is in the range of 1.0 to 62.0%.

【００１１】Ｐｂは、黄銅の切削性を向上させるよう機
能する。好ましい含有範囲は２．０〜３．７％の範囲で
あり、２．０％未満では十分な切削性向上が得られず、
３．７％を越えて含有すると、機械的性質が低下し、脆
化を生じる傾向がある、さらに好ましいＰｂの含有量
は、２．８〜３．１％の範囲である。Pb functions to improve the machinability of brass. The preferred content range is from 2.0 to 3.7%. If the content is less than 2.0%, sufficient improvement in machinability cannot be obtained.
If the content exceeds 3.7%, the mechanical properties tend to decrease and embrittlement tends to occur. A more preferred Pb content is in the range of 2.8 to 3.1%.

【００１２】Ｐは、耐脱亜鉛腐食性を向上させるよう作
用する。とくにα相の脱亜鉛腐食の抑制に効果があり、
０．０２％以上の微量の添加により十分な脱亜鉛腐食性
を示す。また結晶粒を小さくするよう機能する。Ｐの一
部は硬くて脆いＣｕ₃ Ｐ相として存在すること、Ｃｕと
Ｃｕ₃ Ｐ相との共晶温度が７１４℃と低いことを考慮
し、冷間加工性および熱間加工性の観点からＰを多量に
添加することは好ましくなく、機械的性質の低下や脆化
も生じないために、Ｐの上限は０．０７％とするのが好
ましい。さらに好ましいＰに含有範囲は０．０３〜０．
０６％である。P acts to improve the dezincification corrosion resistance. In particular, it is effective in suppressing the dezincification corrosion of the α phase.
Sufficient dezincification corrosion is exhibited by adding a trace amount of 0.02% or more. It also functions to reduce crystal grains. Considering that a part of P exists as a hard and brittle Cu ₃ P phase and the eutectic temperature of Cu and Cu ₃ P phase is as low as 714 ° C., from the viewpoint of cold workability and hot workability. It is not preferable to add a large amount of P, and the upper limit of P is preferably set to 0.07% in order to prevent reduction in mechanical properties and embrittlement. More preferably, the content range of P is 0.03 to 0.3.
06%.

【００１３】Ｓｎは、α相の脱亜鉛腐食を抑制するだけ
でなく、β相の耐脱亜鉛腐食性の向上にも有効に機能す
る。Ｓｎの好ましい含有量は０．２０〜０．５０％の範
囲であり、０．２０％未満ではその効果が小さく、０．
５０％を越えると、熱処理条件によっては硬くて脆いγ
相が析出する場合がある。さらに好ましいＳｎの含有範
囲は０．２５〜０．４０％である。Sn not only suppresses the dezincification corrosion of the α phase but also effectively functions to improve the dezincification corrosion resistance of the β phase. The preferable content of Sn is in the range of 0.20 to 0.50%. When the content is less than 0.20%, the effect is small.
If it exceeds 50%, it may be hard and brittle depending on the heat treatment conditions.
Phases may precipitate. A more preferable Sn content range is 0.25 to 0.40%.

【００１４】Ｆｅは、α相の粗大化を抑制し機械的性質
を安定化させる。Ｆｅの好ましい含有量は０．１０〜
０．３０％の範囲であり、０．１０％未満ではその効果
が十分でなく、０．３０％を越えると、通常のα＋β黄
銅の加工温度以上に保持しないと固溶せず、部分的に結
晶粒の成長を妨害し、結晶粒径が大小混粒となり易く、
機械的性質のばらつきの原因となる。Ｆｅが固溶せず残
留した場合には抽伸破断の原因となる。さらに好ましい
Ｆｅの含有範囲は０．１５〜０．２５％である。なお、
本発明の黄銅には、通常、快削黄銅に不純物として含ま
れる、例えば、０．００５％以下のＳｉ、０．０３％以
下のＡｌ、０．０３％以下のＭｎなどが含有されていて
も本発明の効果に影響を与えることはない。Fe suppresses coarsening of the α phase and stabilizes mechanical properties. The preferred content of Fe is 0.10 to 0.10.
If it is less than 0.10%, the effect is not sufficient, and if it exceeds 0.30%, it does not form a solid solution unless it is kept at a temperature equal to or higher than the normal processing temperature of α + β brass, and is partially dissolved. It hinders the growth of crystal grains, and the crystal grain size tends to be large and small,
It causes variation in mechanical properties. If Fe does not form a solid solution but remains, it causes drawing fracture. More preferably, the content range of Fe is 0.15 to 0.25%. In addition,
Although the brass of the present invention usually contains, as impurities in free-cutting brass, for example, 0.005% or less of Si, 0.03% or less of Al, and 0.03% or less of Mn, It does not affect the effect of the present invention.

【００１５】本発明においては、マトリックスがα相と
β相の２相からなり、且つβ相がα相で分断されている
組織を有することを特徴とする。β相がα相で分断さ
れ、β相が、Ｐ、Ｓｎの添加によって耐脱亜鉛腐食性が
向上したα相で包み込まれるような組織形態とすること
により、脱亜鉛腐食が進行し難くなり、良好な耐脱亜鉛
腐食性が達成される。The present invention is characterized in that the matrix is composed of two phases, α phase and β phase, and that the β phase has a structure separated by the α phase. The β phase is separated by the α phase, and the β phase is wrapped in the α phase in which the dezincification corrosion resistance is improved by the addition of P and Sn, so that the dezincification corrosion hardly proceeds, Good dezincification corrosion resistance is achieved.

【００１６】上記の組織形態を得るための製造方法につ
いて説明すると、まず、上記の組成を有する合金を造塊
し、得られた鋳塊を押出加工する。押出材のマトリック
ス中のβ相は、大部分が連続相として存在している。こ
の押出材の組織に特定の条件による熱処理を施すことに
より、連続したβ相をα相によって分断し、本発明の特
徴とする組織性状とする。The manufacturing method for obtaining the above-mentioned structural form will be described. First, an alloy having the above-described composition is formed into an ingot, and the obtained ingot is extruded. The β phase in the matrix of the extruded material is mostly present as a continuous phase. By subjecting the structure of the extruded material to a heat treatment under specific conditions, the continuous β phase is divided by the α phase to obtain a texture characteristic of the present invention.

【００１７】本発明における熱処理の第１の実施態様
は、前記の鋳塊を、押出加工した後、または押出および
抽伸加工した後、３５０〜５５０℃の温度で、好ましく
は１〜６時間焼鈍処理するものである。前記の組成を有
する合金は、Ｃｕの含有量が低く、常にα相、β相の２
相からなるので押出加工は容易であり、押出後の組織
は、α＋β相からなり、β相は連続した状態で存在す
る。In a first embodiment of the heat treatment according to the present invention, the ingot is subjected to an annealing treatment at a temperature of 350 to 550 ° C., preferably for 1 to 6 hours after extrusion or extrusion and drawing. Is what you do. The alloy having the above composition has a low Cu content, and always has an α phase and a β phase.
Extrusion is easy because it is composed of phases, and the structure after extrusion consists of α + β phase, and β phase exists in a continuous state.

【００１８】３５０〜５５０℃の温度で熱処理を施すこ
とにより、Ｃｕ−Ｚｎ状態図に基づく金相学上の原理に
従って、β相の一部がα相に変化して、組織中のα相の
存在比率が増大し、その結果、残留したβ相はα相によ
って分断されα相に包み込まれたような形態となり耐脱
亜鉛腐食性が向上する。By performing a heat treatment at a temperature of 350 to 550 ° C., a part of the β phase is changed to the α phase according to the principle of metallography based on the Cu—Zn phase diagram, and the existence ratio of the α phase in the structure As a result, the remaining β phase is separated by the α phase and is wrapped in the α phase, thereby improving the dezincification corrosion resistance.

【００１９】熱処理（焼鈍）温度が３５０℃未満ではβ
相の分断効果が十分に得られず、熱処理温度が５５０℃
を越えると、α相からβ相への変態が生じ、β相が増え
て連続相となり、耐食性が劣るようになる。焼鈍処理
後、抽伸加工、矯正仕上げ加工などを施すことができ
る。When the heat treatment (annealing) temperature is lower than 350 ° C., β
The phase separation effect is not sufficiently obtained, and the heat treatment temperature is 550 ° C.
When the temperature exceeds the above range, transformation from the α phase to the β phase occurs, the β phase increases to become a continuous phase, and the corrosion resistance becomes poor. After the annealing treatment, drawing, straightening and finishing can be performed.

【００２０】本発明における熱処理の第２の実施態様
は、前記の鋳塊を、押出加工した後、押出材を１０℃／
秒以下の冷却速度で徐冷するものである。前記のよう
に、本発明の組成を有する合金は、Ｃｕの含有量が低
く、常にα相、β相の２相からなるので押出加工は容易
であり、押出後の組織は、α＋β相からなり、β相は連
続した状態で存在している。In a second embodiment of the heat treatment according to the present invention, the extruded material is extruded at 10 ° C. /
The cooling is performed slowly at a cooling rate of less than one second. As described above, since the alloy having the composition of the present invention has a low Cu content and is always composed of two phases, α phase and β phase, extrusion processing is easy, and the structure after extrusion is composed of α + β phase. , Β phase exist in a continuous state.

【００２１】押出材を１０℃／秒以下の冷却速度で徐冷
することにより、Ｃｕ−Ｚｎ状態図に基づく金相学上の
原理に従って、β相の一部がα相に変化して、組織中の
α相の存在比率が増大し、その結果、残留したβ相はα
相によって分断されα相に包み込まれたような形態とな
り耐脱亜鉛腐食性が向上する。By gradually cooling the extruded material at a cooling rate of 10 ° C./sec or less, a part of the β phase changes to the α phase according to the metallographic principle based on the Cu—Zn phase diagram, and The proportion of the α phase increases, and as a result, the remaining β phase becomes α
The phase is divided by the phase and wrapped in the α phase, and the dezincification corrosion resistance is improved.

【００２２】押出後の冷却速度が１０℃／秒を越える
と、５５０℃を越える高温領域の場合には、β相からβ
＋α相への変態が生じるため、拡散距離が短範囲で足り
るから問題ないが、５５０℃以下の温度域においては、
β相からα相への変態が生じるため、長範囲の拡散が必
要となり、冷却速度に拡散速度が追随し切れず、β相の
分断が不十分となり、十分な耐脱亜鉛腐食性が得られな
い。押出材を徐冷した後、抽伸加工、矯正仕上げ加工な
どを施すことができる。When the cooling rate after extrusion exceeds 10 ° C./sec, in a high temperature range exceeding 550 ° C., β
Since the transformation to the + α phase occurs, the diffusion distance is short, and there is no problem. However, in the temperature range of 550 ° C. or less,
Since the transformation from β phase to α phase occurs, diffusion over a long range is necessary, the diffusion rate cannot follow the cooling rate, the β phase is insufficiently divided, and sufficient dezincification corrosion resistance is obtained. Absent. After the extruded material is gradually cooled, a drawing process, a correction finishing process, and the like can be performed.

【００２３】[0023]

【実施例】以下、本発明の実施例を比較例と対比して説
明するとともに、それに基づいてその効果を実証する。
なお、これらの実施例は、本発明の好ましい一実施態様
を説明するためのものであって、これにより本発明が制
限されるものではない。EXAMPLES Examples of the present invention will be described below in comparison with comparative examples, and the effects thereof will be demonstrated based on them.
It should be noted that these examples are for describing a preferred embodiment of the present invention, and the present invention is not limited thereto.

【００２４】実施例１ リターンスクラップを主原料とし、これに新地金を混合
して添加元素の濃度を調整した表１に示す組成の合金を
溶解、鋳造し、直径２９４ｍｍのビレットに造塊した。Example 1 An alloy having a composition shown in Table 1 in which return scrap was used as a main raw material and a new metal was mixed to adjust the concentration of the added element was melted and cast, and formed into a billet having a diameter of 294 mm.

【００２５】得られた鋳塊を、試験材Ｎｏ．１、Ｎｏ．
４〜６、Ｎｏ．８〜９については、６４０℃の温度で直
径２０ｍｍの棒材に押出加工した後、断面減少率１０％
で抽伸加工し、ついで、表１に示す条件で焼鈍処理し、
さらに断面減少率２０％で抽伸した後、矯正仕上げ加工
した。焼鈍は、電気炉を使用して所定温度に所定時間保
持した後、徐冷することにより行った。The obtained ingot was used as a test material No. 1, No.
Nos. 4 to 6; About 8-9, after extruding to the bar material of diameter 20mm at the temperature of 640 degreeC, cross-sectional reduction rate 10%
And then annealed under the conditions shown in Table 1.
Further, after drawing at a cross-sectional reduction rate of 20%, a corrective finishing process was performed. Annealing was performed by using an electric furnace, maintaining the temperature at a predetermined temperature for a predetermined time, and then gradually cooling.

【００２６】試験材Ｎｏ．２、Ｎｏ．３、Ｎｏ．７およ
びＮｏ．１０については、６４０℃の温度で直径５５〜
７０ｍｍに押出加工した後、表１に示す冷却条件で徐冷
し、断面減少率２０％で抽伸した後、矯正仕上げ加工し
た。なお、押出寸法を違えたのは押出材の冷却速度を調
整するためである。Test material No. 2, No. 3, No. 7 and No. 7 For 10, at a temperature of 640 ° C., a diameter of 55 to 55
After extruding to 70 mm, it was gradually cooled under the cooling conditions shown in Table 1, drawn at a cross-sectional reduction rate of 20%, and then subjected to straightening finishing. The reason why the extrusion size was changed is to adjust the cooling rate of the extruded material.

【００２７】矯正仕上げ加工後の試験材について、下記
の方法により組織観察を行い、加工性、耐脱亜鉛腐食
性、切削性を評価した。 組織観察：焼鈍後、または押出、徐冷後の試験材の縦断
面を顕微鏡で観察し、β相が連続状か分断状かを確認し
た。表１において、βｃはβ相が連続状のものを示し、
βｄはβ相が分断状のものを示す。 加工性：押出加工および抽伸加工中に破断あるいは割れ
が生じたものは不合格（×）、欠陥を生じることなく加
工できたものを合格（○）とした。The structure of the test material after the corrective finishing was observed by the following method, and the workability, the dezincification corrosion resistance, and the machinability were evaluated. Microstructure observation: The longitudinal section of the test material after annealing or after extrusion and slow cooling was observed with a microscope to confirm whether the β phase was continuous or split. In Table 1, βc indicates that the β phase is continuous,
βd indicates that the β phase is split. Workability: A sample that was broken or cracked during extrusion and drawing was rejected (x), and a sample that was processed without defects was passed (o).

【００２８】耐脱亜鉛腐食性：ＩＳＯ法に準拠して、試
験材を７５±３℃のＣｕＣｌ₂ ・２Ｈ₂ Ｏの１２．７ｇ
／ｌ溶液に２４時間浸漬し、脱亜鉛腐食深さを測定し、
以下の基準により評価した。脱亜鉛腐食深さ１００μｍ
以下（実用上脱亜鉛腐食の問題が生じない深さ）のもの
は合格（○）、脱亜鉛腐食深さが１００μｍを越えるも
のは不合格（×） 切削性：一定の条件で切削加工を行い、切粉が細かく分
断して切削性が優れていたものは合格（○）：切屑が連
続したものは不合格（×）とした。Dezincification corrosion resistance: 12.7 g of CuCl ₂ .2H ₂ O at 75 ± 3 ° C. according to the ISO method
/ L solution for 24 hours, measure the dezincification corrosion depth,
Evaluation was made according to the following criteria. Dezincification corrosion depth 100μm
The following (depth that does not cause a problem of dezincification corrosion in practical use) are acceptable (）), and those that have a dezincification corrosion depth exceeding 100 μm are unacceptable (x). Machinability: Cutting under certain conditions In addition, a sample having excellent cutting properties due to fine cutting of chips was passed (O): A sample having continuous chips was rejected (X).

【００２９】組織観察結果、加工性、耐脱亜鉛腐食性、
切削性の評価結果を表２に示す。表２にみられるよう
に、本発明に従う試験材Ｎｏ．１〜１０はいずれも、β
相がα相で分断された組織形態を示し、熱間加工性およ
び冷間加工性は良好であり、優れた切削性、耐脱亜鉛腐
食性を示した。Structure observation results, workability, dezincification corrosion resistance,
Table 2 shows the evaluation results of the machinability. As can be seen from Table 2, the test material No. 1 to 10 are all β
The microstructure exhibited a structure in which the phases were separated by the α phase, and the hot workability and cold workability were good, and excellent cutting properties and dezincification corrosion resistance were exhibited.

【００３０】[0030]

【表１】 [Table 1]

【００３１】[0031]

【表２】 [Table 2]

【００３２】実施例２ リターンスクラップを主原料とし、これに新地金を混合
して添加元素の濃度を調整した表３に示す組成の合金を
溶解、鋳造し、直径２９４ｍｍのビレットに造塊した。Example 2 An alloy having a composition shown in Table 3 in which return scrap was used as a main raw material and a new metal was mixed to adjust the concentration of the added element was melted, cast, and formed into a billet having a diameter of 294 mm.

【００３３】得られた鋳塊を、試験材Ｎｏ．１１、Ｎ
ｏ．１２については、６４０℃の温度で直径２０ｍｍの
棒材に押出加工した後、断面減少率１０％で抽伸加工
し、ついで、表３に示す条件で焼鈍処理し、さらに断面
減少率２０％で抽伸した後、矯正仕上げ加工した。焼鈍
は、電気炉を使用して所定温度に所定時間保持した後、
徐冷することにより行った。The obtained ingot was used as a test material No. 11, N
o. For No. 12, after extrusion at a temperature of 640 ° C. into a rod having a diameter of 20 mm, drawing was performed at a cross-sectional reduction rate of 10%, followed by annealing under the conditions shown in Table 3, and further drawing at a cross-sectional reduction rate of 20%. After that, a corrective finishing process was performed. Annealing, after holding for a predetermined time at a predetermined temperature using an electric furnace,
This was performed by slow cooling.

【００３４】試験材Ｎｏ．１３については、６４０℃の
温度で直径５０ｍｍに押出加工した後、表３に示す冷却
条件で徐冷し、断面減少率２０％で抽伸した後、矯正仕
上げ加工した。なお、試験材Ｎｏ．１１〜１２と押出寸
法を違えたのは押出材の冷却速度を調整するためであ
る。Test material No. 13 was extruded to a diameter of 50 mm at a temperature of 640 ° C., gradually cooled under the cooling conditions shown in Table 3, drawn at a cross-sectional reduction rate of 20%, and then subjected to a straightening finish. The test material No. The reason why the extrusion size is different from that of 11 to 12 is to adjust the cooling rate of the extruded material.

【００３５】矯正仕上げ加工後の試験材について、実施
例１と同一の方法により組織観察を行い、加工性、耐脱
亜鉛腐食性、切削性を評価した。結果を表４に示す。表
４にみられるように、本発明に従う試験材Ｎｏ．１１〜
１３はいずれも、β相がα相で分断された組織形態を示
し、熱間加工性および冷間加工性は良好であり、優れた
切削性、耐脱亜鉛腐食性を示した。With respect to the test material after the corrective finishing, the structure was observed in the same manner as in Example 1 to evaluate the workability, dezincification corrosion resistance, and machinability. Table 4 shows the results. As can be seen in Table 4, the test material No. 11-
All of No. 13 showed a microstructure in which the β phase was separated by the α phase, the hot workability and the cold workability were good, and excellent cutting performance and dezincification corrosion resistance were exhibited.

【００３６】[0036]

【表３】 [Table 3]

【００３７】[0037]

【表４】 [Table 4]

【００３８】比較例１ リターンスクラップを主原料とし、これに新地金を混合
して添加元素の濃度を調整した表３に示す組成の合金を
溶解、鋳造し、直径２９４ｍｍのビレットに造塊した。Comparative Example 1 An alloy having a composition shown in Table 3 in which return scrap was used as a main raw material and a new metal was mixed to adjust the concentration of the added element was melted and cast, and formed into a billet having a diameter of 294 mm.

【００３９】得られた鋳塊を、試験材Ｎｏ．１４、１
５、１７、２０〜２５については、６４０℃の温度で直
径２０ｍｍの棒材に押出加工した後、断面減少率１０％
で抽伸加工し、ついで、表５に示す条件で焼鈍処理し、
さらに断面減少率２０％で抽伸した後、矯正仕上げ加工
した。焼鈍は、電気炉を使用して所定温度に所定時間保
持した後、徐冷することにより行った。The obtained ingot was used as a test material No. 14, 1
For 5, 17, 20 to 25, after extruding into a rod having a diameter of 20 mm at a temperature of 640 ° C., a cross-sectional reduction rate of 10%
And then annealed under the conditions shown in Table 5,
Further, after drawing at a cross-sectional reduction rate of 20%, a corrective finishing process was performed. Annealing was performed by using an electric furnace, maintaining the temperature at a predetermined temperature for a predetermined time, and then gradually cooling.

【００４０】試験材Ｎｏ．１６、Ｎｏ．１８、Ｎｏ．１
９、Ｎｏ．２６については、６４０℃の温度で直径３６
〜６０ｍｍに押出加工した後、表５に示す冷却条件で徐
冷し、断面減少率２０％で抽伸した後、矯正仕上げ加工
した。なお、試験材Ｎｏ．１４〜２６と押出寸法を違え
たのは押出材の冷却速度を調整するためである。Test material No. 16, No. 18, No. 1
9, No. For 26, a diameter of 36 at a temperature of 640 ° C.
After extrusion to 〜60 mm, the material was gradually cooled under the cooling conditions shown in Table 5, drawn at a cross-sectional reduction rate of 20%, and then subjected to straightening finishing. The test material No. The reason why the extrusion size is different from 14 to 26 is to adjust the cooling rate of the extruded material.

【００４１】矯正仕上げ加工後の試験材について、実施
例１と同一の方法により組織観察を行い、加工性、耐脱
亜鉛腐食性、切削性を評価した。結果を表６に示す。な
お、表５において、本発明の条件を外れたものには下線
を付した。With respect to the test material after the corrective finishing, the structure was observed in the same manner as in Example 1 to evaluate the workability, the dezincification corrosion resistance, and the machinability. Table 6 shows the results. In Table 5, those outside the conditions of the present invention are underlined.

【００４２】[0042]

【表５】 [Table 5]

【００４３】[0043]

【表６】 [Table 6]

【００４４】表６に示すように、試験材Ｎｏ．１４はＣ
ｕ含有量が低いため、高温長時間の熱処理を行ってもβ
相が分断されず耐脱亜鉛腐食性が改善されない。また、
β相存在率が高いため冷間加工性が劣り、抽伸加工で破
断が生じた。試験材Ｎｏ．１５はＣｕ量が多いため、β
相存在率が低く熱間加工時の変形抵抗が高くなり、押し
詰まりが生じた。試験材Ｎｏ．１６はＰｂ含有量が低い
ため、切削屑が螺旋状に連なり十分な切削性が得られな
かった。試験材Ｎｏ．１７はＰｂ量が多いため、熱間加
工時にＰｂの溶融に起因して割れが生じ、割れを抑制す
るためには押出速度を低下させなければならなかった。
また、Ｐｂを起点として抽伸時に破断が生じた。As shown in Table 6, the test material No. 14 is C
u content is low, so that β
The phases are not separated, and the dezincification corrosion resistance is not improved. Also,
The cold workability was inferior due to the high β phase abundance, and fracture occurred during drawing. Test material No. 15 has a large amount of Cu,
The phase abundance was low, the deformation resistance during hot working increased, and clogging occurred. Test material No. In No. 16, since the Pb content was low, cutting chips were spirally connected and sufficient cutting properties could not be obtained. Test material No. No. 17 had a large amount of Pb, so cracks were generated due to melting of Pb during hot working, and the extrusion speed had to be reduced to suppress the cracks.
In addition, breakage occurred during drawing from Pb as a starting point.

【００４５】試験材Ｎｏ．１８はＰの含有量が少ないた
め、１００μｍを越える深さの脱亜鉛腐食が生じ、試験
材Ｎｏ．１９はＰ量が多いため、Ｃｕ₃ Ｐを起点として
抽伸時に破断が生じた。試験材Ｎｏ．２０はＳｎ含有量
が低いため、β相の脱亜鉛腐食を抑制する効果が不十分
となり１００μｍを越える深さの脱亜鉛腐食が生じた。
試験材Ｎｏ．２１はＳｎ量が多いため、γ相が析出しγ
相を起点として抽伸時に破断が生じた。試験材Ｎｏ．２
２はＦｅ含有量が低いため、高温の熱処理においてα相
の粗大化が生じ、抽伸加工時の延性不足に起因して割れ
が生じた。試験材Ｎｏ．２３はＦｅ量が多いため、押出
温度の６４０℃ではＦｅが完全に固溶せず、残留したＦ
ｅが起点となって抽伸時に破断が生じた。Test material No. In Test Material No. 18, since the content of P was small, dezincification corrosion occurred to a depth exceeding 100 μm. No. 19 had a large P content, so that fracture occurred during drawing from Cu ₃ P as a starting point. Test material No. In No. 20, since the Sn content was low, the effect of suppressing the dezincification corrosion of the β phase became insufficient and dezincification corrosion having a depth exceeding 100 μm occurred.
Test material No. Since No. 21 has a large amount of Sn, a γ phase precipitates and γ
Breakage occurred during drawing from the phase as a starting point. Test material No. 2
Since No. 2 had a low Fe content, the α phase became coarse during high-temperature heat treatment, and cracks occurred due to insufficient ductility during drawing. Test material No. Since No. 23 has a large amount of Fe, at the extrusion temperature of 640 ° C., Fe did not completely form a solid solution, and
e started and fracture occurred during drawing.

【００４６】試験材Ｎｏ．２４は焼鈍温度は低いため、
β相が完全に分断されず十分な耐脱亜鉛腐食性が得られ
なかった。また、焼鈍後のβ相存在率が低いため抽伸時
に破断が生じた。試験材Ｎｏ．２５は焼鈍温度が高いた
め、β相存在率が高くなり脱亜鉛腐食が顕著となり、抽
伸時の破断発生率も大きくなった。試験材Ｎｏ．２６は
押出後の冷却速度が大きいためα相の析出が不十分とな
り、β相存在率が高く且つβ相がα相により分断され
ず、十分な耐脱亜鉛腐食性が得られなかった。また、抽
伸時の破断発生率も大きくなった。Test material No. 24 has a low annealing temperature,
The β phase was not completely separated, and sufficient dezincification corrosion resistance was not obtained. In addition, since the β phase abundance after annealing was low, fracture occurred during drawing. Test material No. In No. 25, since the annealing temperature was high, the β phase abundance increased, the dezincification corrosion became remarkable, and the fracture occurrence rate during drawing increased. Test material No. In No. 26, the cooling rate after the extrusion was high, so that the precipitation of the α phase was insufficient, the β phase abundance was high, the β phase was not separated by the α phase, and sufficient dezincification corrosion resistance was not obtained. Also, the rate of occurrence of breakage during drawing increased.

【００４７】[0047]

【発明の効果】本発明によれば、優れた耐脱亜鉛腐食性
と切削性をそなえ、熱間加工が容易で、且つリサイクル
性にも優れ、コスト的にも有利な黄銅およびその製造方
法が提供される。According to the present invention, there is provided a brass having excellent dezincification corrosion resistance and machinability, easy to hot work, excellent in recyclability and advantageous in cost, and a method for producing the same. Provided.

【００４８】本発明において必須のＰｂ、ＳｎおよびＦ
ｅは、市況のリターンスクラップに含有されているか
ら、リターンスクラップを主原料として使用し、新地金
は成分調整のためにのみ用いることによって、各含有元
素の濃度範囲を制御することができるから、リサイクル
性が高い、すなわちＬＣＡに優れた耐脱亜鉛腐食性快削
黄銅を提供することが可能となる。Pb, Sn and F essential in the present invention
Since e is contained in the return scrap in the market, the return range is used as the main raw material, and the new ingot is used only for adjusting the components, so that the concentration range of each contained element can be controlled. It is possible to provide a free-cutting brass having high recyclability, that is, dezincification corrosion resistance excellent in LCA.

───────────────────────────────────────────────────── 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） Ｃ２２Ｆ 1/00 ６４０ Ｃ２２Ｆ 1/00 ６４０Ａ ６８２ ６８２ ６８３ ６８３ ６８４ ６８４Ｃ ６９１ ６９１Ｂ ６９２ ６９２Ａ (72)発明者 渥美 哲郎 東京都港区新橋５丁目11番３号 住友軽金 属工業株式会社内 (72)発明者 吉川 善浩 茨城県石岡市大字柏原４番１号 新日東金 属株式会社内──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C22F 1/00 640 C22F 1/00 640A 682 682 683 683 684 684C 691 691B 692 692A (72) Inventor Tetsuro Atsumi Sumitomo Light Metal Industries Co., Ltd., 5-11-3, Shinbashi, Minato-ku, Tokyo (72) Inventor Yoshihiro Yoshikawa 4-1 Kashiwara, Ishioka-shi, Ibaraki Pref.

Claims (3)

【特許請求の範囲】[Claims] 【請求項１】 Ｃｕ：６０．０〜６３．０％（質量％、
以下同じ）、Ｐｂ：２．０〜３．７％、Ｐ：０．０２〜
０．０７％、Ｓｎ：０．２０〜０．５０％、Ｆｅ：０．
１０〜０．２０％を含有し、残部Ｚｎおよび不可避不純
物からなる組成を有し、α相とβ相の２相からなり且つ
β相がα相で分断されている組織を有することを特徴と
する耐脱亜鉛腐食性に優れた快削黄銅。1. Cu: 60.0 to 63.0% (% by mass,
The same applies hereinafter), Pb: 2.0 to 3.7%, P: 0.02 to
0.07%, Sn: 0.20 to 0.50%, Fe: 0.
10 to 0.20%, has a composition consisting of a balance of Zn and unavoidable impurities, has a structure composed of two phases of α phase and β phase and β phase separated by α phase. Free-cutting brass with excellent dezincification corrosion resistance. 【請求項２】 Ｃｕ：６０．０〜６３．０％、Ｐｂ：
２．０〜３．７％、Ｐ：０．０２〜０．０７％、Ｓｎ：
０．２０〜０．５０％、Ｆｅ：０．１０〜０．２０％を
含有し、残部Ｚｎおよび不可避不純物からなる銅合金の
鋳塊を、押出後、または押出および抽伸した後、３５０
〜５５０℃の温度で焼鈍する工程を包含することを特徴
とする請求項１に記載の耐脱亜鉛腐食性に優れた快削黄
銅の製造方法。2. Cu: 60.0 to 63.0%, Pb:
2.0 to 3.7%, P: 0.02 to 0.07%, Sn:
An ingot of a copper alloy containing 0.20 to 0.50% and Fe: 0.10 to 0.20%, the balance being Zn and unavoidable impurities, was extruded or extruded and drawn, and then 350
The method for producing free-cutting brass having excellent dezincification-corrosion resistance according to claim 1, comprising a step of annealing at a temperature of 550 ° C. 3. 【請求項３】 Ｃｕ：６０．０〜６３．０％、Ｐｂ：
２．０〜３．７％、Ｐ：０．０２〜０．０７％、Ｓｎ：
０．２０〜０．５０％、Ｆｅ：０．１０〜０．２０％を
含有し、残部Ｚｎおよび不可避不純物からなる銅合金の
鋳塊を押出後、１０℃／秒以下の冷却速度で徐冷する工
程を包含することを特徴とする請求項１に記載の耐脱亜
鉛腐食性に優れた快削黄銅の製造方法。3. Cu: 60.0 to 63.0%, Pb:
2.0 to 3.7%, P: 0.02 to 0.07%, Sn:
After extruding a copper alloy ingot containing 0.20 to 0.50% and Fe: 0.10 to 0.20%, the balance being Zn and unavoidable impurities, it is gradually cooled at a cooling rate of 10 ° C./sec or less. 2. The method for producing free-cutting brass having excellent dezincification corrosion resistance according to claim 1, further comprising the step of: