JP3917304B2

JP3917304B2 - Free-cutting copper alloy

Info

Publication number: JP3917304B2
Application number: JP28792198A
Authority: JP
Inventors: 恵一郎大石
Original assignee: 三宝伸銅工業株式会社
Priority date: 1998-10-09
Filing date: 1998-10-09
Publication date: 2007-05-23
Anticipated expiration: 2018-10-09
Also published as: AU738301B2; EP1508626A1; DE69828818D1; EP1038981B1; KR20010033101A; EP1508626B1; EP1038981A1; DE69833582T2; JP2000119774A; WO2000022181A1; EP1502964B1; KR100375426B1; TW577931B; EP1038981A4; CA2303512C; DE69835912D1; EP1502964A1; DE69833582D1; DE69835912T2; AU1054099A

Description

【０００１】
【発明の属する技術分野】
本発明は、鉛成分を殆ど含有しない快削性銅合金に関するものである。
【０００２】
【従来の技術】
被削性に優れた銅合金として、一般に、ＪＩＳＨ５１１１ＢＣ６等の青銅系合金やＪＩＳＨ３２５０−Ｃ３６０４，Ｃ３７７１等の黄銅系合金が知られている。これらは１．０〜６．０重量％程度の鉛を含有することによって被削性を向上させたものであり、従来からも、切削加工を必要とする各種製品（例えば、上水道用配管の水栓金具，給排水金具，バルブ等）の構成材として重宝されている。
【０００３】
ところで、鉛はマトリックスに固溶せず、粒状をなして分散することによって、被削性を向上させるものであるが、鉛含有量が１重量％に満たない場合には、切屑が図１（Ｄ）の如く螺旋状に連なった状態で生成してバイトに絡み付く等の種々のトラブルを生じる。一方、鉛含有量が１．０重量％以上であれば、切削抵抗の軽減等を充分に図ることができるが、鉛含有量が２．０重量％に満たない場合には切削表面が粗くなる。したがって、工業的に満足しうる被削性を確保するためには、鉛含有量を２．０重量％以上としておくのが普通である。一般に、高度の切削加工が要求される銅合金展伸材においては約３．０重量％以上の鉛が含有されており、青銅系の鋳物においては約５重量％の鉛が含有されている。例えば、上記したＪＩＳＨ５１１１ＢＣ６では鉛含有量が約５．０重量％である。
【０００４】
【発明が解決しようとする課題】
しかし、鉛は人体や環境に悪影響を及ぼす有害物質であるところから、近時においては、その用途が大幅に制限される傾向にある。例えば、合金の溶解，鋳造等の高温作業時に発生する金属蒸気には鉛成分が含まれることになり、或いは飲料水等との接触により水栓金具や弁等から鉛成分が溶出する虞れがあり、人体や環境衛生上問題がある。そこで、近時、米国等の先進国においては銅合金における鉛含有量を大幅に制限する傾向にあり、わが国においても鉛含有量を可及的に低減した快削性銅合金の開発が強く要請されている。
【０００５】
本発明は、かかる世界的な傾向及び要請に応えるべくなされたもので、鉛の含有量を従来の快削性銅合金に比して大幅に低減させつつも、工業的に充分満足しうる被削性を確保しうる快削性銅合金を提供することを目的とするものである。
【０００６】
【課題を解決するための手段】
本発明は、上記の目的を達成すべく、次のような快削性銅合金を提案する。
【０００７】
従来の鉛添加合金に於いては、鉛添加量１ｗｔ％以上で切削の分断性がある程度改善できると共に切削抵抗の軽減を充分に図ることができ、更に鉛添加量２ｗｔ％以上で切削面状態が改善されるが、本願発明では、より少ない０．０２〜０．４ｗｔ％の鉛添加量でもって従前の少なくとも１ｗｔ％以上の鉛を添加した鉛添加銅合金に優るとも劣ることのない被削性を具備した快削性銅合金を提供するものである。
すなわち、第１発明においては、被削性に優れた銅合金として、銅６９〜７９重量％と珪素２．０〜４．０重量％と鉛０．０２〜０．４重量％とを含有し、且つ残部が亜鉛からなる合金組成をなすと共に、γ相及びκ相の少なくとも一方を含む金属組織をなし、切屑の分断性、切削抵抗、仕上げ粗さの総合的な被削性に優れ、工業的に十分満足し得る被削性を具備する快削性銅合金（以下「第１発明合金」という）を提案する。
【０００８】
鉛はマトリックスに固溶せず、粒状をなして分散することによって、被削性を向上させるものである。一方、珪素は金属組織中にγ相（場合によってはκ相）を出現させることにより、被削性を改善するものである。このように、両者は合金特性における機能を全く異にするものであるが、被削性を改善させる点では共通する。かかる点に着目して、第１発明合金は、珪素を添加することにより、工業的に満足しうる被削性を確保しつつ、鉛含有量の大幅な低減を可能としたものである。すなわち、第１発明合金は、珪素の添加によるγ相形成により被削性を改善したものである。
【０００９】
而して、珪素の添加量が２．０重量％未満では、工業的に満足しうる被削性を確保するに充分なγ相の形成が行われない。また、被削性は珪素添加量の増大に伴って向上するが、４．０重量％を超えて添加しても、その添加量に見合う被削性改善効果はない。ところで、珪素は融点が高く比重が小さいため又酸化し易いため、合金溶融時に珪素単体で炉内に装入すると、当該珪素が湯面に浮くと共に、溶融時に酸化されて珪素酸化物ないし酸化珪素となり、珪素含有銅合金の製造が困難となる。したがって、珪素含有銅合金の鋳塊製造にあっては、通常、珪素添加をＣｕ−Ｓｉ合金とした上で行うことになり、製造コストが高くなる。このような合金製造コストを考慮した場合にも、被削性改善効果が飽和状態となる量（４．０重量％）を超えて珪素を添加することは好ましくない。また、実験によれば、珪素を２．０〜４．０重量％添加したときにおいて、Ｃｕ−Ｚｎ系合金本来の特性を維持するためには、亜鉛含有量との関係をも考慮した場合、銅含有量は６９〜７９重量％の範囲としておくことが好ましいことが判明した。このような理由から、第１発明合金にあっては、銅及び珪素の含有量を夫々６９〜７９重量％及び２．０〜４．０重量％とした。なお、珪素の添加により、被削性が改善される他、鋳造時の湯流れ性，強度，耐摩耗性，耐応力腐蝕割れ性，耐高温酸化性も改善される。また、延性，耐脱亜鉛腐蝕性も或る程度改善される。
【００１０】
一方、鉛の添加量は、次の理由から０．０２〜０．４重量％とした。すなわち、第１発明合金では、上記した如き機能を有する珪素を添加したことにより、鉛添加量を低減しても被削性を確保できるが、特に、従来の快削性銅合金より優れた被削性を得るためには、鉛を０．０２重量％以上添加する必要がある。しかし、鉛添加量が０．４重量％を超えると、却って切削表面が粗くなると共に、熱間での加工性（例えば、鍛造性）が悪くなり、冷間での延性も低下する。そして、鉛添加量が０．４重量％以下の微量であれば、わが国を含めた先進各国において近い将来制定されるであろう鉛含有量規制が如何に厳格なものであったとしても、その規制を充分にクリアすることができると考えられる。なお、後述する第２〜第１１発明合金においても、上記した理由から、鉛の添加量は０．０２〜０．４重量％とされている。
【００１１】
また、第２発明においては、同じく被削性に優れた銅合金として、銅６９〜７９重量％と、珪素２．０〜４．０重量％と、鉛０．０２〜０．４重量％と、ビスマス０．０２〜０．４重量％、テルル０．０２〜０．４重量％及びセレン０．０２〜０．４重量％から選択された１種の元素とを含有し、且つ残部が亜鉛からなる合金組成をなすと共に、γ相及びκ相の少なくとも一方を含む金属組織をなし、切屑の分断性、切削抵抗、仕上げ粗さの総合的な被削性に優れ、工業的に十分満足し得る被削性を具備する快削性銅合金（以下「第２発明合金」という）を提案する。
【００１２】
すなわち、第２発明合金は、第１発明合金にビスマス０．０２〜０．４重量％、テルル０．０２〜０．４重量％及びセレン０．０２〜０．４重量％の１つを更に含有させた合金組成をなすものである。
【００１３】
ビスマス、テルル又はセレンは、鉛と同様に、マトリックスに固溶せず、粒状をなして分散することによって、被削性を向上させる機能を発揮するものであり、鉛の添加量不足を補いうるものである。したがって、これらの何れかを珪素及び鉛と共添させると、珪素及び鉛の添加による被削性改善限度を超えて被削性を更に向上させることが可能となる。第２発明合金では、かかる点に着目して、第１発明合金における被削性を更に改善すべく、ビスマス、テルル及びセレンのうちの１つを添加させることとした。特に、珪素及び鉛に加えてビスマス、テルル又はセレンを添加することにより、複雑な形状を高速で切削加工する場合にも、高度の被削性を発揮する。しかし、ビスマス、テルル又はセレンの添加による被削性向上効果は、各々の添加量が０．０２重量％未満では発揮されない。一方、これらは銅に比して高価なものであるから、０．４重量％を超えて添加しても、被削性は僅かながらも添加量の増加に応じて向上するものの、経済的に添加量に見合う程の効果は認められない。また、添加量が０．４重量％を超えると、熱間での加工性（例えば、鍛造性等）が悪くなり、冷間での加工性（延性）も低下する。しかも、ビスマス等の重金属について仮に鉛同様の問題が生じる可能性があったとしても、０．４重量％以下の微量添加であれば、格別の問題を生じる虞れもないと考えられる。これらの点から、第２発明合金では、ビスマス、テルル又はセレンの添加量を０．０２〜０．４重量％とした。なお、鉛とビスマス、テルル又はセレンとを共添させる場合、両者の合計添加量は０．４重量％以下となるようにしておくことが好ましい。けだし、合計添加量が０．４重量％を僅かでも超えると、それらの単独添加量が０．４重量％を超える場合ほどではないが、熱間での加工性や冷間での延性が低下し始め、或いは切屑形態が図１（Ｂ）から同図（Ａ）へと移行する虞れがあるからである。ところで、ビスマス、テルル又はセレンは上記した如く珪素と異なる機能により被削性を向上させるものであるから、これらの添加により銅及び珪素の適正含有量は影響されない。したがって、第２発明合金における銅及び珪素の含有量は第１発明合金と同一とした。
【００１４】
また、第３発明においては、同じく被削性に優れた銅合金として、銅７０〜８０重量％と、珪素１．８〜３．５重量％と、鉛０．０２〜０．４重量％と、錫０．３〜３．５重量％、アルミニウム１．０〜３．５重量％及び燐０．０２〜０．２５重量％から選択された１種以上の元素とを含有し、且つ残部が亜鉛からなる合金組成をなすと共に、γ相及びκ相の少なくとも一方を含む金属組織をなし、切屑の分断性、切削抵抗、仕上げ粗さの総合的な被削性に優れ、工業的に十分満足し得る被削性を具備する快削性銅合金（以下「第３発明合金」という）を提案する。
【００１５】
錫は、Ｃｕ−Ｚｎ系合金に添加した場合、珪素と同様に、γ相を形成して被削性を向上させるものである。例えば、錫は、５８〜７０重量％のＣｕを含有するＣｕ−Ｚｎ系合金において１．８〜４．０重量％添加させることにより、珪素が添加されておらずとも、良好な被削性を示す。したがって、Ｃｕ−Ｓｉ−Ｚｎ系合金に錫を添加させることにより、γ相の形成を促進させることができ、Ｃｕ−Ｓｉ−Ｚｎ系合金の被削性を更に向上させることができる。錫によるγ相の形成は１．０重量％以上で行なわれ、３．５重量％に達すると飽和状態となる。なお、錫の添加量が３．５重量％を超えると、γ相の形成効果が飽和状態となるばかりでなく、却って延性が低下する。また、錫の添加量が１．０重量％未満ではγ相の形成効果が少ないものの、添加量が０．３重量％以上であれば、珪素により形成されるγ相を分散させて均一化させる効果があり、このようなγ相の分散効果によっても被削性が改善される。すなわち、錫の添加量が０．３重量％以上であれば、その添加により被削性が改善されることになる。
【００１６】
また、アルミニウムも、錫と同様に、γ相形成を促進させる機能を有するものであり、錫と共に或いはこれに代えて添加することにより、Ｃｕ−Ｓｉ−Ｚｎ系合金の被削性を更に向上させることができる。アルミニウムには、被削性の他、強度，耐摩耗性，耐高温酸化性を改善させる機能や合金比重を低下させる機能ももあるが、被削性改善機能が発揮されるためには、少なくとも１．０重量％添加させる必要がある。しかし、３．５重量％を超えて添加しても、添加量に見合った被削性改善効果はみられないし、錫と同様に延性の低下を招来する。
【００１７】
また、燐には、錫やアルミニウムのようなγ相の形成機能はないが、珪素の添加により又はこれと錫，アルミニウムの一方若しくは両方を共添させることにより生成したγ相を均一に分散して、γ相分布を良好なものとする機能があり、かかる機能によってγ相形成による被削性の更なる向上を図ることができる。また、燐の添加により、γ相の分散化と同時にマトリックスにおけるα相の結晶粒を微細化して、熱間加工性を向上させ、強度，耐応力腐蝕割れ性も向上させる。さらに、鋳造時の湯流れ性を著しく向上させる効果もある。このような燐添加による効果は０．０２重量％未満の添加では発揮されない。一方、燐の添加量が０．２５重量％を超えると、添加量に見合った被削性改善等の効果は得られないし、過剰添加により却って熱間鍛造性，押出性の低下を招来する。
【００１８】
第３発明合金では、かかる点に着目して、Ｃｕ−Ｓｉ−Ｐｂ−Ｚｎ系合金（第１発明合金）に、錫０．３〜３．５重量％、アルミニウム１．０〜３．５重量％及び燐０．０２〜０．２５重量％のうち少なくとも１つを添加させることより、被削性の更なる向上を図っている。
【００１９】
ところで、錫、アルミニウム又は燐は、上記した如くγ相の形成機能又はγ相の分散機能により被削性を改善させるものであり、γ相による被削性改善を図る上で、珪素と密接な関係を有するものである。したがって、珪素に錫、アルミニウム又は燐を共添させた第３発明合金では、第１発明合金の珪素に置き換えて被削性を向上させる機能が発揮され、γ相とは関係なく被削性を改善させる機能（マトリックスに粒状をなして分散することにより被削性を向上させる機能）を発揮するビスマス、テルル又はセレンを添加した第２発明合金に比して、珪素の必要添加量が少なくなる。すなわち、珪素添加量が２．０重量％未満であっても、１．８重量％以上であれば、錫、アルミニウム又は燐の共添により、工業的に満足しうる被削性を得ることができる。しかし、珪素の添加量が４．０重量％以下であっても、３．５重量％を超えると、錫、アルミニウム又は燐を共添することにより、珪素添加による被削性改善効果は飽和状態となる。かかる点から、第３発明合金では、珪素の添加量を１．８〜３．５重量％とした。また、かかる珪素の添加量との関係及び錫、アルミニウム又は燐を添加させることとの関係から、銅配合量の上下限値は第２発明合金より若干大きくして、その好ましい含有量を７０〜８０重量％とした。
【００２０】
また、第４発明においては、同じく被削性に優れた銅合金として、銅７０〜８０重量％と、珪素１．８〜３．５重量％と、鉛０．０２〜０．４重量％と、錫０．３〜３．５重量％、アルミニウム１．０〜３．５重量％及び燐０．０２〜０．２５重量％から選択された１種以上の元素と、ビスマス０．０２〜０．４重量％、テルル０．０２〜０．４重量％及びセレン０．０２〜０．４重量％から選択された１種の元素とを含有し、且つ残部が亜鉛からなる合金組成をなすと共に、γ相及びκ相の少なくとも一方を含む金属組織をなし、切屑の分断性、切削抵抗、仕上げ粗さの総合的な被削性に優れ、工業的に十分満足し得る被削性を具備する快削性銅合金（以下「第４発明合金」という）を提案する。
【００２１】
すなわち、第４発明合金は、第３発明合金にビスマス０．０２〜０．４重量％、テルル０．０２〜０．４重量％及びセレン０．０２〜０．４重量％の何れかを更に含有させた合金組成をなすものであり、これらを添加させる理由及び添加量の決定理由は第２発明合金について述べたと同様である。
【００２２】
また、第５発明においては、被削性に加えて耐蝕性にも優れた銅合金として、銅６９〜７９重量％と、珪素２．０〜４．０重量％と、鉛０．０２〜０．４重量％と、錫０．３〜３．５重量％、燐０．０２〜０．２５重量％、アンチモン０．０２〜０．１５重量％及び砒素０．０２〜０．１５重量％から選択された１種以上の元素とを含有し、且つ残部が亜鉛からなる合金組成をなすと共に、γ相及びκ相の少なくとも一方を含む金属組織をなし、切屑の分断性、切削抵抗、仕上げ粗さの総合的な被削性に優れ、工業的に十分満足し得る被削性を具備する快削性銅合金（以下「第５発明合金」という）を提案する。
【００２３】
すなわち、第５発明合金は、第１発明合金に錫０．３〜３．５重量％、燐０．０２〜０．２５重量％、アンチモン０．０２〜０．１５重量％及び砒素０．０２〜０．１５重量％の少なくとも１つを更に含有させた合金組成をなすものである。
【００２４】
錫には、被削性改善機能の他、耐蝕性（耐脱亜鉛腐蝕性，耐漬食性）及び鍛造性を向上させる機能がある。すなわち、α相マトリックスの耐蝕性を向上させ、γ相の分散化により耐蝕性、鍛造性及び耐応力腐蝕割れ性の改善を図ることができる。第５発明合金では、錫のかかる機能により耐蝕性の改善を図り、被削性の改善は主として珪素添加効果により図っている。したがって、珪素及び銅の含有量は第１発明合金と同一としてある。一方、耐蝕性，鍛造性の改善機能を発揮させるためには、錫の添加量を少なくとも０．３重量％とする必要がある。しかし、錫添加による耐蝕性，鍛造性の改善機能は、３．５重量％を超えて添加しても、添加量に見合うだけの効果が得られず、経済的にも無駄である。
【００２５】
また、燐は、上記した如くγ相を均一分散化させる共にマトリックスにおけるα相の結晶粒を細分化させることにより、被削性改善機能の他、耐蝕性（耐脱亜鉛腐食性，耐漬食性）、鍛造性、耐応力腐蝕割れ性及び機械的強度を向上させる機能を発揮するものである。第５発明合金では、燐のかかる機能により耐蝕性等の改善を図り、被削性の改善は主として珪素添加効果により図っている。燐添加による耐蝕性等の改善効果は、微量の燐添加により発揮されるものであり、０．０２重量％以上の添加で発揮される。しかし、０．２５重量％を超えて添加しても、添加量に見合った効果が得られないばかりか、熱間鍛造性，押出性が却って低下する。
【００２６】
また、アンチモン及び砒素も、燐と同様に、微量（０．０２重量％以上）で耐脱亜鉛腐食性等を向上させるものである。しかし、０．１５重量％を超えて添加しても、添加量に見合う効果が得られないばかりか、燐の過剰添加と同様に、熱間鍛造性，押出性が却って低下する。
【００２７】
これらのことから、第５発明合金では、第１発明合金におけると同量の銅、珪素及び鉛に加えて、耐蝕性向上元素として錫、燐、アンチモン及び砒素の少なくとも１つを上記した範囲内で添加させることにより、被削性のみならず、耐蝕性等をも向上させることができるのである。なお、第５発明合金にあっては、錫及び燐は、主として、アンチモン及び砒素と同様の耐蝕性改善元素として機能するため、珪素及び微量の鉛以外に被削性改善元素を添加しない第１発明合金と同様に、銅及び珪素の配合量は、夫々、６９〜７９重量％及び２．０〜４．０重量％としてある。
【００２８】
また、第６発明においては、同じく被削性及び耐蝕性に優れた銅合金として、銅６９〜７９重量％と、珪素２．０〜４．０重量％と、鉛０．０２〜０．４重量％と、錫０．３〜３．５重量％、燐０．０２〜０．２５重量％、アンチモン０．０２〜０．１５重量％及び砒素０．０２〜０．１５重量％から選択された１種以上の元素と、ビスマス０．０２〜０．４重量％、テルル０．０２〜０．４重量％及びセレン０．０２〜０．４重量％から選択された１種の元素とを含有し、且つ残部が亜鉛からなる合金組成をなすと共に、γ相及びκ相の少なくとも一方を含む金属組織をなし、切屑の分断性、切削抵抗、仕上げ粗さの総合的な被削性に優れ、工業的に十分満足し得る被削性を具備する快削性銅合金（以下「第６発明合金」という）を提案する。
【００２９】
すなわち、第６発明合金は、第５発明合金にビスマス０．０２〜０．４重量％、テルル０．０２〜０．４重量％及びセレン０．０２〜０．４重量％の何れか１つを更に含有させた合金組成をなすものであり、第２発明合金と同様に、珪素及び鉛に加えてビスマス、テルル及びセレンの何れか１つを添加することにより被削性を改善すると共に、第５発明合金と同様に、錫、燐、アンチモン及び砒素のうちから選択した少なくとも１つを添加することにより耐蝕性等を改善したものである。したがって、銅、珪素、鉛、ビスマス、テルル及びセレンの添加量については第２発明合金と同一とし、錫、燐、アンチモン及び砒素の添加量については第５発明合金と同一とした。
【００３０】
また、第７発明においては、被削性に加えて高力性，耐摩耗性に優れた銅合金として、銅６２〜７８重量％と、珪素２．５〜４．５重量％と、鉛０．０２〜０．４重量％と、錫０．３〜３．０重量％、アルミニウム０．２〜２．５重量％及び燐０．０２〜０．２５重量％から選択された１種以上の元素と、マンガン０．７〜３．５重量％及びニッケル０．７〜３．５重量％から選択された１種以上の元素とを含有し、且つ残部が亜鉛からなる合金組成をなすと共に、γ相及びκ相の少なくとも一方を含む金属組織をなし、切屑の分断性、切削抵抗、仕上げ粗さの総合的な被削性に優れ、工業的に十分満足し得る被削性を具備する快削性銅合金（以下「第７発明合金」という）を提案する。
【００３１】
マンガン又はニッケルは、珪素と結合してＭｎX ＳｉY 又はＮｉX ＳｉY の微細金属間化合物を形成して、マトリックスに均一に析出し、それにより耐摩耗性，強度を向上させる。したがって、マンガン及びニッケルの一方又は両方を添加することにより、高力性，耐摩耗性が改善される。かかる効果は、マンガン及びニッケルを夫々０．７重量％以上添加することに発揮される。しかし、３．５重量％を超えて添加しても、効果が飽和状態となり、添加量に見合う効果が得られない。珪素は、マンガン又はニッケルの添加に伴い、これらとの金属間化合物形成に要する消費量を考慮して、２．５〜４．５重量％を添加させることとした。
【００３２】
また、錫、アルミニウム及び燐の添加により、マトリックスのα相が強化され、被削性も改善される。錫及び燐は、α相，γ相の分散により強度，耐摩耗性を向上させ、被削性も向上させる。錫は、０．３重量％以上の添加により強度及び被削性を向上させるが、３．０重量％を超えて添加すると延性が低下する。したがって、高力性，耐摩耗性の改善を図る第７発明合金においては、被削性改善効果も考慮して、錫の添加量を０．３〜３．０重量％とした。また、アルミニウムは、耐摩耗性改善に寄与し、マトリックスの強化機能は０．２重量％以上の添加により発揮される。しかし、２．５重量％を超えて添加すると、延性が低下する。したがって、被削性改善効果も考慮して、アルミニウムの添加量は０．２〜２．５重量％とした。また、燐の添加により、γ相の分散化と同時にマトリックスにおけるα相の結晶粒を微細化して、熱間加工性を向上させ、強度，耐摩耗性も向上させる。しかも、鋳造時の湯流れ性を著しく向上させる効果もある。このような効果は、燐を０．０２〜０．２５重量％の範囲で添加することにより奏せられる。なお、銅の配合量については、珪素添加量との関係及びマンガン，ニッケルが珪素と結合する関係から、６２〜７８重量％とした。
【００３３】
さらに、第８発明においては、被削性に加えて耐高温酸化性に優れた銅合金として、銅６９〜７９重量％、珪素２．０〜４．０重量％、鉛０．０２〜０．４重量％、アルミニウム０．１〜１．５重量％及び燐０．０２〜０．２５重量％を含有し、且つ残部が亜鉛からなる合金組成をなすと共に、γ相及びκ相の少なくとも一方を含む金属組織をなし、切屑の分断性、切削抵抗、仕上げ粗さの総合的な被削性に優れ、工業的に十分満足し得る被削性を具備する快削性銅合金（以下「第８発明合金」という）を提案する。
【００３４】
アルミニウムは、強度，被削性，耐摩耗性を改善させる他、耐高温酸化性を改善させる元素である。また、珪素も、上記した如く、被削性，強度，耐摩耗性，耐応力腐蝕割れ性を改善させる他、耐高温酸化性を改善する機能を発揮する。アルミニウムによる耐高温酸化性の改善は、珪素との共添によって、０．１重量％以上の添加で行なわれる。しかし、アルミニウムを１．５重量％を超えて添加しても、添加量に見合う耐高温酸化性改善効果はみられない。かかる点から、アルミニウムの添加量は０．１〜１．５重量％とした。
【００３５】
燐は、合金鋳造時における湯流れ性を向上させるために添加される。また、燐は、かかる湯流れ性の他、上記した被削性，耐脱亜鉛腐蝕性に加えて、耐高温酸化性をも改善する。このような燐の添加効果は０．０２重量％以上で発揮される。しかし、０．２５重量％を超えて添加しても、添加量に見合う効果はみられず、却って合金の脆性化を招くことになる。かかる点から、燐の添加量は、０．０２〜０．２５重量％とした。
【００３６】
また、珪素は、上記した如く被削性を改善させるために添加されるものであるが、燐と同様に湯流れ性を向上させる機能も有するものである。珪素による湯流れ性の向上は２．０重量％以上の添加により発揮され、被削性を向上させるに必要な添加範囲と重複する。したがって、珪素の添加量は、被削性の改善を考慮して、２．０〜４．０重量％とした。
【００３７】
また、第９発明においては、同じく被削性及び耐高温酸化性に優れた銅合金として、銅６９〜７９重量％と、珪素２．０〜４．０重量％と、鉛０．０２〜０．４重量％と、アルミニウム０．１〜１．５重量％と、燐０．０２〜０．２５重量％と、ビスマス０．０２〜０．４重量％、テルル０．０２〜０．４重量％及びセレン０．０２〜０．４重量％から選択された１種の元素とを含有し、且つ残部が亜鉛からなる合金組成をなすと共に、γ相及びκ相の少なくとも一方を含む金属組織をなし、切屑の分断性、切削抵抗、仕上げ粗さの総合的な被削性に優れ、工業的に十分満足し得る被削性を具備する快削性銅合金（以下「第９発明合金」という）を提案する。
【００３８】
すなわち、第９発明合金は、第８発明合金にビスマス０．０２〜０．４重量％、テルル０．０２〜０．４重量％及びセレン０．０２〜０．４重量％の何れかを更に含有させた合金組成をなすものであり、前記した如く鉛同様の被削性を改善する元素であるビスマス等を添加することにより、第８発明合金と同様の耐高温酸化性を確保しつつ、被削性の更なる改善を図ったものである。
【００３９】
また、第１０発明においては、同じく被削性及び耐高温酸化性に優れた銅合金として、銅６９〜７９重量％と、珪素２．０〜４．０重量％と、鉛０．０２〜０．４重量％と、アルミニウム０．１〜１．５重量％と、燐０．０２〜０．２５重量％と、クロム０．０２〜０．４重量％及びチタン０．０２〜０．４重量％から選択された１種以上の元素とを含有し、且つ残部が亜鉛からなる合金組成をなすと共に、γ相及びκ相の少なくとも一方を含む金属組織をなし、切屑の分断性、切削抵抗、仕上げ粗さの総合的な被削性に優れ、工業的に十分満足し得る被削性を具備する快削性銅合金（以下「第１０発明合金」という）を提案する。
【００４０】
クロム及びチタンは耐高温酸化性を向上させる機能を有するものであり、その機能は、特に、アルミニウムとの共添による相乗効果によって顕著に発揮される。かかる機能は、これらを単独添加すると共添するとに拘わらず、夫々、０．０２重量％以上で発揮され、０．４重量％で飽和状態となる。このような点から、第１０発明合金においては、第８発明合金にクロム０．０２〜０．４重量％及びチタン０．０２〜０．４重量％の少なくとも１つを更に含有させた合金組成をなすものとして、第８発明合金の耐高温酸化性を更に向上させるべく図っている。
【００４１】
また、第１１発明においては、同じく被削性及び耐高温酸化性に優れた銅合金として、銅６９〜７９重量％と、珪素２．０〜４．０重量％と、鉛０．０２〜０．４重量％と、アルミニウム０．１〜１．５重量％と、燐０．０２〜０．２５重量％と、クロム０．０２〜０．４重量％及びチタン０．０２〜０．４重量％から選択された１種以上の元素と、ビスマス０．０２〜０．４重量％、テルル０．０２〜０．４重量％及びセレン０．０２〜０．４重量％から選択された１種の元素とを含有し、且つ残部が亜鉛からなる合金組成をなすと共に、γ相及びκ相の少なくとも一方を含む金属組織をなし、切屑の分断性、切削抵抗、仕上げ粗さの総合的な被削性に優れ、工業的に十分満足し得る被削性を具備する快削性銅合金（以下「第１１発明合金」という）を提案する。
【００４２】
すなわち、第１１発明合金は、第１０発明合金にビスマス０．０２〜０．４重量％、テルル０．０２〜０．４重量％及びセレン０．０２〜０．４重量％の何れか１つを更に含有させた合金組成をなすものであり、前記した如く珪素と異なる機能により被削性を改善する鉛同様元素であるビスマス等を添加することにより、第１０発明合金と同様の耐高温酸化性を確保しつつ、被削性の更なる改善を図ったものである。
【００４３】
また、第１２発明においては、上記した各発明合金に４００〜６００℃で３０分〜５時間の熱処理を施して、γ相を微細に分散析出させておくことにより、その被削性を更に改善した快削性銅合金（以下「第１２発明合金」という）を提案する。
【００４４】
第１〜第１１発明合金は珪素等の被削性改善元素を添加したものであり、かかる元素の添加により優れた被削性を有するものであるが、かかる添加元素の機能による被削性は熱処理によって更に向上する場合がある。例えば、第１〜第１１発明合金における銅濃度が高いものであって、γ相が少なく且つκ相が多いもののについては、熱処理によりκ相がγ相に変化して、γ相が微細に分散析出することにより、被削性が更に改善される。また、実際の鋳物，展伸材，熱間鍛造品の製造を想定した場合、鋳造条件や熱間加工（熱間押出，熱間鍛造等）後の生産性，作業環境等の条件によって、それらの材料が強制空冷，水冷される場合がある。かかる場合、第１〜第１１発明合金において、特に、銅濃度が低いものでは、γ相が若干少なく且つβ相を含んでいるが、熱処理を施すと、これによりβ相がγ相に変化すると共にγ相が微細に分散析出することになり、被削性が改善される。しかし、何れの場合においても、熱処理温度が４００℃未満であれば、上記した相変化速度が遅くなり、熱処理に極めて長時間を要するため、経済的にも実用できない。逆に、６００℃を超えると、却ってκ相が増大し或いはβ相が出現するため、被削性の改善効果が得られない。したがって、実用性をも考慮した場合、被削性改善のためには、４００〜６００℃の条件で３０分〜５時間の熱処理を行なうことが好ましい。
【００４５】
【実施例】
実施例として、表１〜表１５に示す組成の鋳塊（外径１００ｍｍ，長さ１５０ｍｍの円柱形状のもの）を熱間（７５０℃）で外径１５ｍｍの丸棒状に押出加工して、第１発明合金Ｎｏ．１００１〜Ｎｏ．１００７、第２発明合金Ｎｏ．２００１〜Ｎｏ．２００６、第３発明合金Ｎｏ．３００１〜Ｎｏ．３０１０、第４発明合金Ｎｏ．４００１〜Ｎｏ．４０２１、第５発明合金Ｎｏ．５００１〜Ｎｏ．５０２０、第６発明合金Ｎｏ．６００１〜Ｎｏ．６０４５、第７発明合金Ｎｏ．７００１〜Ｎｏ．７０２９、第８発明合金Ｎｏ．８００１〜Ｎｏ．８００８、第９発明合金Ｎｏ．９００１〜Ｎｏ．９００６、第１０発明合金Ｎｏ．１０００１〜Ｎｏ．１０００８及び第１１発明合金Ｎｏ．１１００１〜Ｎｏ．１１０１１を得た。また、表１６に示す組成の鋳塊（外径１００ｍｍ，長さ１５０ｍｍの円柱形状のもの）を熱間（７５０℃）で外径１５ｍｍの丸棒状に押出加工した上、その押出材を表１６に示す条件で熱処理して、第１２発明合金Ｎｏ．１２００１〜Ｎｏ．１２００４を得た。すなわち、Ｎｏ．１２００１は第１発明合金Ｎｏ．１００６と同一組成をなす押出材を５８０℃，３０分の条件で熱処理したものであり、Ｎｏ．１２００２はＮｏ．１００６と同一組成をなす押出材を４５０℃，２時間の条件で熱処理したものであり、Ｎｏ．１２００３は第１発明合金Ｎｏ．１００７と同一組成をなす押出材をＮｏ．１２００１と同一条件（５８０℃，３０分）で熱処理したものであり、Ｎｏ．１２００４はＮｏ．１００７と同一組成をなす押出材をＮｏ．１２００２と同一条件（４５０℃，２時間）で熱処理したものである。
【００４６】
また、比較例として、表１７に示す組成の鋳塊（外径１００ｍｍ，長さ１５０ｍｍの円柱形状のもの）を熱間（７５０℃）で押出加工して、外径１５ｍｍの丸棒状押出材（以下「従来合金」という）Ｎｏ．１３００１〜Ｎｏ．１３００６を得た。なお、Ｎｏ．１３００１は「ＪＩＳＣ３６０４」に相当するものであり、Ｎｏ．１３００２は「ＣＤＡＣ３６０００」に相当するものであり、Ｎｏ．１３００３は「ＪＩＳＣ３７７１」に相当するものであり、Ｎｏ．１３００４は「ＣＤＡＣ６９８００」に相当するものである。また、Ｎｏ．１３００５は「ＪＩＳＣ６１９１」に相当するものであり、ＪＩＳに規定される伸銅品の中で強度，耐磨耗性に最も優れるアルミニウム青銅である。また、Ｎｏ．１３００６は「ＪＩＳＣ４６２２」に相当するものであり、ＪＩＳに規定される伸銅品の中で耐蝕性に最も優れるネーバル黄銅である。
【００４７】
【表１】

【００４８】
【表２】

【００４９】
【表３】

【００５０】
【表４】

【００５１】
【表５】

【００５２】
【表６】

【００５３】
【表７】

【００５４】
【表８】

【００５５】
【表９】

【００５６】
【表１０】

【００５７】
【表１１】

【００５８】
【表１２】

【００５９】
【表１３】

【００６０】
【表１４】

【００６１】
【表１５】

【００６２】
【表１６】

【００６３】
【表１７】

【００６４】
そして、第１〜第１２発明合金の被削性を従来合金との比較において確認すべく、次のような切削試験を行い、切削主分力、切屑状態及び切削表面形態を判定した。
【００６５】
すなわち、上記の如くして得られた各押出材の外周面を、真剣バイト（すくい角：−８°）を取り付けた旋盤により、切削速度：５０ｍ／分，切込み深さ（切削代）：１．５ｍｍ，送り量：０．１１ｍｍ／ｒｅｖ．の条件で切削し、バイトに取り付けた３分力動力計からの信号を重歪測定器により電圧信号に変換してレコーダで記録し、これを切削抵抗に換算した。ところで、切削抵抗の大小は３分力つまり主分力、送り分力及び背分力によって判断されるが、ここでは、３分力のうち最も大きな値を示す主分力（Ｎ）をもって切削抵抗の大小を判断することとした。その結果は、表１８〜表３３に示す通りであった。
【００６６】
また、切削により生成した切屑の状態を観察し、その形状によって図１（Ａ）〜（Ｄ）に示す如く４つに分類して、表１〜表１５に示した。ところで、切屑が、（Ｄ）図に示す如く、３巻以上の螺旋形状をなしている場合には、切屑の処理（切屑の回収や再利用等）が困難となる上、切屑がバイトに絡み付いたり、切削表面を損傷させる等のトラブルが発生して、良好な切削加工を行なうことができない。また、切屑が、（Ｃ）図に示す如く、半巻程度の円弧形状から２巻程度の螺旋形状をなしている場合には、３巻以上の螺旋形状をなす場合のような大きなトラブルは生じないものの、やはり切屑の処理が容易ではなく、連続切削加工を行う場合等にあってはバイトへの絡み付きや切削表面の損傷等を生じる虞れがある。しかし、切屑が、（Ａ）の如き微細な針形状片や（Ｂ）の如き扇形状片又は円弧形状片に剪断される場合には、上記のようなトラブルが生じることがなく、（Ｃ）図や（Ｄ）図に示すもののように嵩張らないことから、切屑の処理も容易である。但し、切屑が（Ａ）図のような微細形状に剪断される場合には、旋盤等の工作機械の摺動面に潜り込んで機械的障害を発生したり、作業者の手指，目に刺さる等の危険を伴うことがある。したがって、被削性を判断する上では、（Ｂ）図に示すものが最良であり、（Ａ）図に示すものがこれに続き、（Ｃ）図や（Ｄ）図に示すものは不適当とするのが相当である。表１８〜表３３においては、（Ｂ）に示す最良の切屑状態が観察されたものを「◎」で、（Ａ）図に示すやや良好な切屑状態が観察されたものを「○」で、（Ｃ）図に示す不良な切屑状態が観察されたものを「△」で、（Ｄ）に示す最悪の切屑状態が観察されたものを「×」で示した。
【００６７】
また、切削後において、切削表面の良否を表面粗さにより判定した。その結果は、表１８〜表３３に示す通りであった。ところで、表面粗さの基準としては最大高さ（Ｒmax ）が使用されることが多く、黄銅製品の用途にもよるが、一般に、Ｒmax ＜１０μｍであれば極めて被削性に優れると判断することができ、１０μｍ≦Ｒmax ＜１５μｍであれば工業的に満足しうる被削性を得ることができたものと判断でき、Ｒmax ≧１５μｍの場合には被削性に劣るものと判断できる。表１８〜表３３においては、Ｒmax ＜１０μｍの場合を「○」で、１０μｍ≦Ｒmax ＜１５μｍの場合を「△」で、Ｒmax ≧１５μｍの場合を「×」で示した。
【００６８】
表１８〜表３３に示す切削試験の結果から明らかなように、第１発明合金Ｎｏ．１００１〜Ｎｏ．１００７、第２発明合金Ｎｏ．２００１〜Ｎｏ．２００６、第３発明合金Ｎｏ．３００１〜Ｎｏ．３０１０、第４発明合金Ｎｏ．４００１〜Ｎｏ．４０２１、第５発明合金Ｎｏ．５００１〜Ｎｏ．５０２０、第６発明合金Ｎｏ．６００１〜Ｎｏ．６０４５、第７発明合金Ｎｏ．７００１〜Ｎｏ．７０２９、第８発明合金Ｎｏ．８００１〜Ｎｏ．８００８、第９発明合金Ｎｏ．９００１〜Ｎｏ．９００６、第１０発明合金Ｎｏ．１０００１〜Ｎｏ．１０００８、第１１発明合金Ｎｏ．１１００１〜Ｎｏ．１１０１１及び第１２発明合金Ｎｏ．１２００１〜Ｎｏ．１２００４は、その何れにおいても、鉛を大量に含有する従来合金Ｎｏ．１３００１〜Ｎｏ．１３００３と同等の被削性を有するものである。特に、切屑の生成状態に限っては、鉛含有量が０．１重量％以下である従来合金Ｎｏ．１３００４〜Ｎｏ．１３００６に比しては勿論、鉛を大量に含有する従来合金Ｎｏ．１３００１〜Ｎｏ．１３００３に比しても、良好な被削性を有する。また、第１発明合金Ｎｏ．１００６及びＮｏ．１００７に比して、これを熱処理した第１２発明合金Ｎｏ．１２００１〜Ｎｏ．１２００４は同等以上の被削性を有しており、合金組成等の条件によっては、熱処理により第１〜第１１発明合金の被削性を更に向上させ得ることが理解される。
【００６９】
次に、第１〜第１２発明合金の熱間加工性及び機械的性質を、従来合金との比較において確認すべく、次のような熱間圧縮試験及び引張試験を行った。
【００７０】
すなわち、上記の如くして得られた各押出材から同一形状（外径１５ｍｍ，長さ２５ｍｍ）の第１及び第２試験片を切り出した。そして、熱間圧縮試験においては、各第１試験片を７００℃に加熱して３０分間保持した上、軸線方向に７０％の圧縮率で圧縮（第１試験片の高さ（長さ）が２５ｍｍから７．５ｍｍになるまで圧縮）して、圧縮後の表面形態（７００℃変形能）を目視判定した。その結果は、表１８〜表３３に示す通りであった。変形能の判定は試験片側面におけるクラックの状態から目視により行い、表１８〜表３３においては、クラックが全く生じなかったものを「○」で、小さなクラックが生じたものを「△」で、大きなクラックが生じたものを「×」で示した。また、各第２試験片を使用して、常法による引張試験を行ない、引張強さ（Ｎ／ｍｍ²）及び伸び（％）を測定した。
【００７１】
表１８〜表３３に示す熱間圧縮試験及び引張試験の結果から、第１〜第１２発明合金は、従来合金Ｎｏ．１３００１〜Ｎｏ．１３００４及びＮｏ．１３００６と同等若しくはそれ以上の熱間加工性及び機械的性質を有するものであり、工業的に好適に使用できるものであることが確認された。特に、第７発明合金については、ＪＩＳに規定される伸銅品の中で強度に最も優れるアルミニウム青銅である従来合金Ｎｏ．１３００５と同等の機械的性質を有するものであり、高力性に優れることが理解される。
【００７２】
また、第１〜第６発明合金及び第８〜第１２発明合金の耐蝕性及び耐応力腐蝕割れ性を、従来合金との比較において確認すべく、「ＩＳＯ６５０９」に定める方法による脱亜鉛腐蝕試験及び「ＪＩＳＨ３２５０」に規定される応力腐蝕割れ試験を行った。
【００７３】
すなわち、「ＩＳＯ６５０９」の脱亜鉛腐蝕試験においては、各押出材から採取した試料を、暴露試料表面が当該押出材の押出し方向に対して直角となるようにしてフェノール樹脂材に埋込み、試料表面をエメリー紙により１２００番まで研磨した後、これを純水中で超音波洗浄して乾燥した。かくして得られた被腐蝕試験試料を、１．０％の塩化第２銅２水和塩（ＣｕＣｌ２・２Ｈ₂Ｏ）の水溶液（１２．７ｇ／ｌ）中に浸漬し、７５℃の温度条件下で２４時間保持した後、水溶液中から取出して、その脱亜鉛腐蝕深さの最大値（最大脱亜鉛腐蝕深さ）を測定した。その結果は、表１８〜表２５及び表２８〜表３３に示す通りであった。
【００７４】
表１８〜表２５及び表２８〜表３３に示す脱亜鉛腐蝕試験の結果から理解されるように、第１〜第４発明合金及び第８〜第１２発明合金は、大量の鉛を含有する従来合金Ｎｏ．１３００１〜Ｎｏ．１３００３に比して優れた耐蝕性を有し、特に、被削性と共に耐蝕性の向上を図った第５及び第６発明合金については、ＪＩＳに規定される伸銅品の中で耐蝕性に最も優れるネーバル黄銅である従来合金Ｎｏ．１３００６に比しても極めて優れた耐蝕性を有することが確認された。
【００７５】
また、「ＪＩＳＨ３２５０」の応力腐蝕割れ試験においては、各押出材から長さ１５０ｍｍの試料を切り出し、各試料を、その中央部を半径４０ｍｍの円弧状治具に当てた状態で、その一端部が他端部に対して４５°となるように折曲させて、試験片とした。このようにして引張残留応力を付加された各試験片を脱脂，乾燥処理した上、１２．５％のアンモニア水（アンモニアを等量の純水で薄めたもの）を入れたデシケータ内のアンモニア雰囲気（２５℃）中に保持させた。すなわち、各試験片をデシケータ内におけるアンモニア水面から約８０ｍｍ上方の位置に保持する。そして、試験片のアンモニア雰囲気中における保持時間が、２時間，８時間，２４時間を経過した時点で、試験片をデシケータから取り出して、１０％の硫酸で洗浄した上、当該試験片の割れの有無を拡大鏡（倍率：１０倍）で視認した。その結果は、表１８〜表２５及び表２８〜表３３に示す通りであった。これらの表においては、アンモニア雰囲気中での保持時間が２時間である場合に明瞭な割れが認められたものについては「××」で、２時間経過時においては割れが認められなかったが、８時間経過時においては明瞭な割れが認められたものについては「×」で、８時間経過時においては割れが認められなかったが、２４時間経過時においては明瞭な割れが認められたものについては「△」で、２４時間経過時においても割れが全く認められなかったものについては「○」で示した。
【００７６】
表１８〜表２５及び表２８〜表３３に示す応力腐蝕割れ試験の結果から理解されるように、被削性と共に耐蝕性の向上を図った第５及び第６発明合金については勿論、耐蝕性については格別の配慮をしていない第１〜第４発明合金及び第８〜第１２発明合金についても、亜鉛を含まないアルミニウム青銅である従来合金Ｎｏ．１３００５と同等の耐応力腐蝕割れ性を有し、ＪＩＳに規定される伸銅品の中で耐蝕性に最も優れるネーバル黄銅である従来合金Ｎｏ．１３００６より優れた耐応力腐蝕割れ性を有することが確認された。
【００７７】
また、第８〜第１１発明合金の耐高温酸化性を、従来合金との比較において確認すべく、次のような酸化試験を行った。
【００７８】
すなわち、各押出材Ｎｏ．８００１〜Ｎｏ．８００８、Ｎｏ．９００１〜Ｎｏ．９００６、Ｎｏ．１０００１〜Ｎｏ．１０００８、Ｎｏ．１１００１〜Ｎｏ．１１０１１及びＮｏ．１３００１〜１３００６から、外径が１４ｍｍとなるように表面研削され且つ長さ３０ｍｍに切断された丸棒状の試験片を得て、各試験片の重量（以下「酸化前重量」という）を測定した。しかる後、各試験片を、磁性坩堝に収納した状態で、５００℃に保持された電気炉内に放置した。そして、放置時間が１００時間を経過した時点で電気炉から取り出して、各試験片の重量（以下「酸化後重量」という）を測定した上、酸化前重量と酸化後重量とから酸化増量を算出した。ここに、酸化増量とは、試験片の表面積１０ｃｍ2 当たりの酸化による増加重量（ｍｇ）の程度を示すものであり、「酸化増量（ｍｇ／１０ｃｍ2 ）＝（酸化後重量（ｍｇ）−酸化前重量（ｍｇ））×（１０ｃｍ²／試験片の表面積（ｃｍ²）」の式から算出されたものである。すなわち、各試験片の酸化後重量は酸化前重量より増加しているが、これは高温酸化によるものである。つまり、高温に晒されると、酸素と銅，亜鉛，珪素とが結合してＣｕ2Ｏ，ＺｎＯ，ＳｉＯ²となり、その酸素増分により重量が増加するのである。したがって、この増加重量の程度（酸化増量）が小さい程、耐高温酸化性に優れているということができ、表２８〜表３１及び表３３に示す結果となった。
【００７９】
表２３〜表３１及び表３３に示す酸化試験の結果から明らかなように、第８〜第１１発明合金の酸化増量は、ＪＩＳに規定される伸銅品の中でも高度の耐高温酸化性を有するアルミニウム青銅である従来合金Ｎｏ．１３００５と同等であり、他の従来合金よりは極めて小さくなっている。したがって、第８〜第１１発明合金が、被削性に加えて、耐高温酸化性にも極めて優れたものであることが確認された。
【００８０】
【表１８】

【００８１】
【表１９】

【００８２】
【表２０】

【００８３】
【表２１】

【００８４】
【表２２】

【００８５】
【表２３】

【００８６】
【表２４】

【００８７】
【表２５】

【００８８】
【表２６】

【００８９】
【表２７】

【００９０】
【表２８】

【００９１】
【表２９】

【００９２】
【表３０】

【００９３】
【表３１】

【００９４】
【表３２】

【００９５】
【表３３】

【００９６】
また、第２の実施例として、表９〜表１１に示す組成の鋳塊（外径１００ｍｍ，長さ２００ｍｍの円柱形状のもの）を熱間（７００℃）で外径３５ｍｍの丸棒状に押出加工して、第７発明合金Ｎｏ．７００１ａ〜Ｎｏ．７０２９ａを得た。また、第２の比較例として、表１７に示す組成の鋳塊（外径１００ｍｍ，長さ２００ｍｍの円柱形状のもの）を熱間（７００℃）で押出加工して、外径３５ｍｍの丸棒状押出材（以下「従来合金」という）Ｎｏ．１３００１ａ〜Ｎｏ．１３００６ａを得た。なお、Ｎｏ．７００１ａ〜Ｎｏ．７０２９ａ及びＮｏ．１３００１ａ〜Ｎｏ．１３００６ａは、夫々、前記した銅合金Ｎｏ．７００１〜Ｎｏ．７０２９及びＮｏ．１３００１〜Ｎｏ．１３００６と同一の合金組成をなすものである。
【００９７】
そして、第７発明合金Ｎｏ．７００１ａ〜Ｎｏ．７０２９ａの耐摩耗性を、従来合金Ｎｏ．１３００１ａ〜Ｎｏ．１３００６ａとの比較において確認すべく、次のような摩耗試験を行った。
【００９８】
すなわち、上記の如くして得られた各押出材から、その外周面を切削した上、穴明け加工及び切断加工を施すことにより、外径３２ｍｍ，厚さ（軸線方向長さ）１０ｍｍのリング状試験片を得た上、各試験片を回転自在な軸に嵌合固定して、これと軸線を平行とする外径４８ｍｍのＳＵＳ３０４製ロールに５０ｋｇの荷重を掛けて押圧接触させた状態に保持させる。しかる後、ＳＵＳ３０４製ロール及びこれに転接する試験片を、当該試験片の外周面にマルチオイルを滴下しつつ、同一回転数（２０９ｒ．ｐ．ｍ．）で回転駆動させる。そして、当該試験片の回転数が１０万回に達した時点で、ＳＵＳ３０４製ロール及び試験片の回転を停止して、各試験片の回転前後における重量差つまり摩耗減量（ｍｇ）を測定した。かかる摩耗減量が少ない程、耐摩耗性に優れた銅合金ということができるが、その結果は、表３４〜表３６に示す通りであった。
【００９９】
表３４〜表３６に示す摩耗試験の結果から明らかなように、第７発明合金Ｎｏ．７００１ａ〜Ｎｏ．７０２９ａは、従来合金Ｎｏ．１３００１〜Ｎｏ．１３００４及びＮｏ．１３００６に比しては勿論、ＪＩＳに規定される伸銅品の中で耐磨耗性に最も優れるアルミニウム青銅である従来合金Ｎｏ．１３００５に比しても、耐摩耗性が優れることが確認された。したがって、上記した引張試験の結果をも考慮して総合的に判断した場合、第７発明合金は、被削性に加えて、ＪＩＳに規定される伸銅品の中で耐磨耗性に最も優れるアルミニウム青銅と同等以上の高力性，耐摩耗性を有するものであるということができる。
【０１００】
【表３４】

【０１０１】
【表３５】

【０１０２】
【表３６】

【０１０３】
【発明の効果】
以上の説明から容易に理解されるように、第１〜第１２発明合金は、被削性改善元素である鉛の含有量が極く微量（０．０２〜０．４重量％）であるにも拘わらず、極めて被削性に富むものであり、鉛を大量に含有する従来の快削性銅合金の代替材料として安全に使用できるものであり、切屑の再利用等を含めて環境衛生上の問題が全くなく、鉛含有製品が規制されつつある近時の傾向に充分対応することができる。
【０１０４】
さらに、第５及び第６発明合金は、被削性に加えて耐蝕性にも優れるものであり、耐蝕性を必要とする切削加工品，鍛造品，鋳物製品等（例えば、給水栓，給排水金具，バルブ，ステム，給湯配管部品，シャフト，熱交換器部品等）の構成材として好適に使用することができるものであり、その実用的価値極めて大なるものである。
【０１０５】
また、第７発明合金は、被削性に加えて高力性，耐摩耗性にも優れるものであり、高力性，耐摩耗性を必要とする切削加工品，鍛造品，鋳物製品等（例えば、軸受，ボルト，ナット，ブッシュ，歯車，ミシン部品，油圧部品等）の構成材として好適に使用することができるものであり、その実用的価値極めて大なるものである。
【０１０６】
また、第８〜第１１発明合金は、被削性に加えて耐高温酸化性にも優れるものであり、耐高温酸化性を必要とする切削加工品，鍛造品，鋳物製品等（例えば、石油・ガス温風ヒータ用ノズル，バーナヘッド，給湯器用ガスノズル等）の構成材として好適に使用することができるものであり、その実用的価値極めて大なるものである。
【図面の簡単な説明】
【図１】切屑の形態を示す斜視図である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a free-cutting copper alloy containing almost no lead component.
[0002]
[Prior art]
  In general, bronze alloys such as JIS H5111 BC6 and brass alloys such as JIS H3250-C3604 and C3771 are known as copper alloys having excellent machinability. These have improved machinability by containing about 1.0 to 6.0% by weight of lead. Conventionally, various products that require cutting work (for example, water for water supply piping) It is useful as a component of plug fittings, water supply / drainage fittings, valves, etc.).
[0003]
  By the way, lead does not dissolve in the matrix but is dispersed in a granular form to improve machinability. However, when the lead content is less than 1% by weight, the chips are formed as shown in FIG. Various troubles such as being generated in a spiral-like state and being entangled with the cutting tool as shown in FIG. On the other hand, if the lead content is 1.0% by weight or more, the cutting resistance can be sufficiently reduced, but if the lead content is less than 2.0% by weight, the cutting surface becomes rough. . Therefore, in order to ensure industrially satisfactory machinability, the lead content is usually set to 2.0% by weight or more. Generally, a copper alloy wrought material that requires a high degree of cutting contains about 3.0% by weight or more of lead, and a bronze-based casting contains about 5% by weight of lead. For example, the above-mentioned JIS H5111 BC6 has a lead content of about 5.0% by weight.
[0004]
[Problems to be solved by the invention]
  However, since lead is a harmful substance that adversely affects the human body and the environment, its use has recently been greatly limited. For example, the metal vapor generated during high-temperature work such as melting or casting of an alloy may contain lead components, or lead components may be eluted from faucet fittings or valves due to contact with drinking water or the like. Yes, there are human and environmental health problems. Therefore, recently, in developed countries such as the United States, there is a tendency to significantly limit the lead content in copper alloys, and in Japan too, there is a strong demand for the development of free-cutting copper alloys with as low a lead content as possible. Has been.
[0005]
  The present invention has been made in response to such global trends and demands, and is capable of sufficiently satisfying industrial requirements while significantly reducing the lead content compared to conventional free-cutting copper alloys. An object of the present invention is to provide a free-cutting copper alloy that can ensure machinability.
[0006]
[Means for Solving the Problems]
  In order to achieve the above object, the present invention proposes the following free-cutting copper alloy.
[0007]
In the conventional lead-added alloy, the cutting ability can be improved to some extent when the lead addition amount is 1 wt% or more, and the cutting resistance can be sufficiently reduced. Further, when the lead addition amount is 2 wt% or more, the cutting surface state is improved. Although improved, in the present invention, the machinability is not inferior to the lead-added copper alloy to which at least 1 wt% or more of lead is added with a smaller amount of lead addition of 0.02 to 0.4 wt%. It provides a free-cutting copper alloy comprising
  That is, in the first invention, the copper alloy having excellent machinability contains 69 to 79% by weight of copper, 2.0 to 4.0% by weight of silicon, and 0.02 to 0.4% by weight of lead. And a metal composition containing at least one of a γ phase and a κ phase, and having an alloy composition with the balance being zinc.None, excellent chip machinability of chips, cutting resistance, finish roughness, and machinability that can be satisfactorily industrially satisfiedA free-cutting copper alloy (hereinafter referred to as “first invention alloy”) is proposed.
[0008]
  Lead does not dissolve in the matrix, but is dispersed in a granular form to improve machinability. On the other hand, silicon improves machinability by causing a γ phase (in some cases, a κ phase) to appear in the metal structure. As described above, both have completely different functions in alloy characteristics, but are common in improving machinability. By paying attention to this point, the first invention alloy can significantly reduce the lead content while ensuring industrially satisfactory machinability by adding silicon. That is, the first invention alloy has improved machinability by forming a γ phase by adding silicon.
[0009]
  Thus, when the amount of silicon added is less than 2.0% by weight, the γ phase sufficient to ensure industrially satisfactory machinability cannot be formed. In addition, machinability improves with an increase in the amount of silicon added, but even if it exceeds 4.0% by weight, there is no machinability improving effect commensurate with the amount added. By the way, since silicon has a high melting point and a low specific gravity, it is easy to oxidize. Therefore, when silicon is charged into the furnace as a single element when the alloy is melted, the silicon floats on the molten metal surface and is oxidized at the time of melting to form silicon oxide or silicon oxide. Thus, it becomes difficult to produce a silicon-containing copper alloy. Therefore, in the production of an ingot of a silicon-containing copper alloy, it is usually performed after adding silicon to a Cu—Si alloy, and the production cost is increased. Even in consideration of such an alloy manufacturing cost, it is not preferable to add silicon beyond the amount (4.0 wt%) at which the machinability improving effect becomes saturated. Also, according to experiments, when 2.0 to 4.0% by weight of silicon is added, in order to maintain the original characteristics of the Cu—Zn alloy, when the relationship with the zinc content is also considered, It has been found that the copper content is preferably in the range of 69 to 79% by weight. For these reasons, in the first invention alloy, the contents of copper and silicon were 69 to 79% by weight and 2.0 to 4.0% by weight, respectively. In addition to the improvement of machinability, the addition of silicon improves the flowability, strength, wear resistance, stress corrosion cracking resistance, and high temperature oxidation resistance during casting. In addition, ductility and dezincification corrosion resistance are improved to some extent.
[0010]
  On the other hand, the amount of lead added was set to 0.02 to 0.4% by weight for the following reason. That is, in the first invention alloy, by adding silicon having the above-described function, machinability can be ensured even if the amount of lead added is reduced. In order to obtain machinability, it is necessary to add 0.02% by weight or more of lead. However, if the amount of lead added exceeds 0.4% by weight, the cutting surface becomes rough, the hot workability (for example, forgeability) deteriorates, and the cold ductility also decreases. And if the amount of lead added is as small as 0.4 wt% or less, no matter how strict the lead content regulations will be enacted in the near future in advanced countries including Japan, It is thought that the regulations can be fully cleared. In addition, in the second to eleventh invention alloys to be described later, the amount of lead added is 0.02 to 0.4% by weight for the reason described above.
[0011]
  Further, in the second invention, as a copper alloy having excellent machinability, copper 69 to 79% by weight, silicon 2.0 to 4.0% by weight, lead 0.02 to 0.4% by weight, 1 element selected from 0.02 to 0.4% by weight of bismuth, 0.02 to 0.4% by weight of tellurium and 0.02 to 0.4% by weight of selenium, with the balance being zinc And a metal structure including at least one of a γ phase and a κ phase.None, excellent chip machinability of chips, cutting resistance, finish roughness, and machinability that can be satisfactorily industrially satisfiedA free-cutting copper alloy (hereinafter referred to as “second invention alloy”) is proposed.
[0012]
  That is, the second invention alloy further includes one of bismuth 0.02 to 0.4 wt%, tellurium 0.02 to 0.4 wt% and selenium 0.02 to 0.4 wt% to the first invention alloy. The alloy composition is included.
[0013]
  Bismuth, tellurium, or selenium, like lead, does not dissolve in the matrix, but exhibits a function of improving machinability by being dispersed in a granular form, and can compensate for the lack of lead addition. Is. Therefore, when any of these is co-added with silicon and lead, it becomes possible to further improve the machinability beyond the machinability improvement limit by the addition of silicon and lead. In the second invention alloy, paying attention to this point, one of bismuth, tellurium and selenium is added to further improve the machinability of the first invention alloy. In particular, by adding bismuth, tellurium or selenium in addition to silicon and lead, a high degree of machinability is exhibited even when a complicated shape is cut at a high speed. However, the machinability improving effect due to the addition of bismuth, tellurium or selenium is not exhibited when the addition amount is less than 0.02% by weight. On the other hand, since these are expensive compared to copper, even if added in excess of 0.4% by weight, the machinability is slightly improved as the added amount increases, but economically. The effect corresponding to the amount added is not recognized. On the other hand, when the added amount exceeds 0.4% by weight, hot workability (for example, forgeability) is deteriorated, and cold workability (ductility) is also lowered. Moreover, even if heavy metals such as bismuth may cause the same problem as lead, if a trace amount of 0.4% by weight or less is added, it is considered that there is no possibility of causing a special problem. From these points, in the second invention alloy, the addition amount of bismuth, tellurium or selenium was set to 0.02 to 0.4% by weight. In addition, when lead and bismuth, tellurium, or selenium are co-added, it is preferable that the total addition amount of both be 0.4% by weight or less. However, if the total addition amount exceeds 0.4 wt%, it is not as much as when the single addition amount exceeds 0.4 wt%, but hot workability and cold ductility are reduced. It is because there exists a possibility that it may start, or a chip | tip form may transfer to FIG. 1 (A) from FIG. 1 (B). By the way, since bismuth, tellurium, or selenium improves machinability by a function different from silicon as described above, the appropriate content of copper and silicon is not affected by the addition of these. Therefore, the copper and silicon contents in the second invention alloy were the same as those in the first invention alloy.
[0014]
  Further, in the third invention, as a copper alloy that is also excellent in machinability, copper 70 to 80% by weight, silicon 1.8 to 3.5% by weight, lead 0.02 to 0.4% by weight, One or more elements selected from 0.3 to 3.5% by weight of tin, 1.0 to 3.5% by weight of aluminum and 0.02 to 0.25% by weight of phosphorus, and the balance It has an alloy composition composed of zinc and a metal structure containing at least one of a γ phase and a κ phase.None, excellent chip machinability of chips, cutting resistance, finish roughness, and machinability that can be satisfactorily industrially satisfiedA free-cutting copper alloy (hereinafter referred to as “third invention alloy”) is proposed.
[0015]
  Tin, when added to a Cu—Zn-based alloy, forms a γ phase and improves machinability, similar to silicon. For example, tin is added to 1.8 to 4.0 wt% in a Cu-Zn alloy containing 58 to 70 wt% of Cu, so that good machinability can be obtained even if silicon is not added. Show. Therefore, by adding tin to the Cu—Si—Zn alloy, the formation of the γ phase can be promoted, and the machinability of the Cu—Si—Zn alloy can be further improved. Formation of the γ phase with tin is carried out at 1.0% by weight or more, and when it reaches 3.5% by weight, it becomes saturated. If the added amount of tin exceeds 3.5% by weight, not only the effect of forming the γ phase becomes saturated, but also the ductility decreases. Further, if the addition amount of tin is less than 1.0% by weight, the effect of forming the γ phase is small, but if the addition amount is 0.3% by weight or more, the γ phase formed by silicon is dispersed and homogenized. There is an effect, and the machinability is also improved by the dispersion effect of the γ phase. That is, if the addition amount of tin is 0.3% by weight or more, the machinability is improved by the addition.
[0016]
  Aluminum, like tin, has a function of promoting the formation of the γ phase, and is added together with or instead of tin to further improve the machinability of the Cu—Si—Zn alloy. be able to. In addition to machinability, aluminum also has a function to improve strength, wear resistance, high-temperature oxidation resistance and a function to lower alloy specific gravity, but in order to exhibit machinability improving function, at least It is necessary to add 1.0% by weight. However, even if added over 3.5% by weight, the machinability improving effect commensurate with the added amount is not observed, and the ductility is lowered similarly to tin.
[0017]
  Phosphorus does not have the function of forming a γ phase like tin or aluminum, but uniformly disperses the γ phase generated by adding silicon or by co-adding one or both of tin and aluminum. Thus, there is a function of improving the γ phase distribution, and this function can further improve the machinability by forming the γ phase. Addition of phosphorus also makes it possible to refine the α phase crystal grains in the matrix simultaneously with the dispersion of the γ phase, improve the hot workability, and improve the strength and stress corrosion resistance. Furthermore, there is also an effect of remarkably improving the hot water flow during casting. Such an effect due to the addition of phosphorus is not exhibited when the addition is less than 0.02% by weight. On the other hand, if the addition amount of phosphorus exceeds 0.25% by weight, effects such as improvement of machinability corresponding to the addition amount cannot be obtained, and excessive addition causes a decrease in hot forgeability and extrudability.
[0018]
  In the third invention alloy, focusing on this point, the Cu-Si-Pb-Zn alloy (first invention alloy) is added to 0.3 to 3.5 wt% tin and 1.0 to 3.5 wt% aluminum. % And phosphorus by 0.02 to 0.25% by weight are added to further improve the machinability.
[0019]
  By the way, tin, aluminum, or phosphorus improves the machinability by the function of forming the γ phase or the function of dispersing the γ phase as described above. In order to improve the machinability by the γ phase, it is close to silicon. It has a relationship. Therefore, in the third invention alloy in which tin, aluminum or phosphorus is co-added to silicon, the machinability is improved by replacing the silicon of the first invention alloy with the machinability irrespective of the γ phase. Compared with the second invention alloy to which bismuth, tellurium or selenium is added which exhibits the function of improving (the function of improving the machinability by dispersing in the form of particles in the matrix), the required addition amount of silicon is reduced. . That is, even if the silicon addition amount is less than 2.0% by weight, if it is 1.8% by weight or more, industrially satisfactory machinability can be obtained by co-addition of tin, aluminum or phosphorus. it can. However, even if the amount of silicon added is 4.0% by weight or less, if it exceeds 3.5% by weight, the machinability improving effect due to silicon addition is saturated by adding tin, aluminum or phosphorus together. It becomes. From this point, in the third invention alloy, the amount of silicon added is 1.8 to 3.5% by weight. Further, from the relationship with the addition amount of silicon and the addition of tin, aluminum, or phosphorus, the upper and lower limit values of the copper blending amount are slightly larger than those of the second invention alloy, and the preferable content thereof is 70 to 70. 80% by weight.
[0020]
  Further, in the fourth invention, as a copper alloy having excellent machinability, copper 70 to 80% by weight, silicon 1.8 to 3.5% by weight, lead 0.02 to 0.4% by weight, One or more elements selected from tin, 0.3-3.5 wt%, aluminum, 1.0-3.5 wt%, and phosphorus, 0.02-0.25 wt%, and bismuth, 0.02-0 .4% by weight, tellurium 0.02 to 0.4% by weight and selenium 0.02 to 0.4% by weight and one element selected from the alloy, with the balance being zinc. A metal structure including at least one of γ phase and κ phase,Excellent chip machinability, cutting resistance, and overall machinability of finishing roughness, with industrially satisfactory machinability.A free-cutting copper alloy (hereinafter referred to as “fourth invention alloy”) is proposed.
[0021]
  That is, in the fourth invention alloy, any one of bismuth 0.02 to 0.4 wt%, tellurium 0.02 to 0.4 wt% and selenium 0.02 to 0.4 wt% is further added to the third invention alloy. The alloy composition is included, and the reason for adding these and the reason for determining the amount added are the same as those described for the second invention alloy.
[0022]
  Further, in the fifth invention, as a copper alloy having excellent corrosion resistance in addition to machinability, 69 to 79% by weight of copper, 2.0 to 4.0% by weight of silicon, and 0.02 to 0 of lead .4 wt%, tin 0.3-3.5 wt%, phosphorus 0.02-0.25 wt%, antimony 0.02-0.15 wt% and arsenic 0.02-0.15 wt% An alloy composition containing at least one selected element and the balance of zinc, and a metal structure including at least one of a γ phase and a κ phase;Excellent chip machinability, cutting resistance, and overall machinability of finishing roughness, with industrially satisfactory machinability.A free-cutting copper alloy (hereinafter referred to as “fifth invention alloy”) is proposed.
[0023]
  That is, the fifth invention alloy is the same as the first invention alloy in the range of 0.3 to 3.5 wt% tin, 0.02 to 0.25 wt% phosphorus, 0.02 to 0.15 wt% antimony and 0.02 wt% arsenic. The alloy composition further contains at least one of ˜0.15% by weight.
[0024]
  In addition to the machinability improving function, tin has a function of improving corrosion resistance (dezincing corrosion resistance, pickling resistance) and forgeability. That is, the corrosion resistance of the α phase matrix can be improved, and the dispersion of the γ phase can improve the corrosion resistance, forgeability, and stress corrosion cracking resistance. In the fifth invention alloy, the corrosion resistance is improved by the function of tin, and the machinability is improved mainly by the effect of silicon addition. Therefore, the contents of silicon and copper are the same as those of the first invention alloy. On the other hand, in order to exert the function of improving the corrosion resistance and forgeability, the amount of tin added needs to be at least 0.3% by weight. However, the function of improving corrosion resistance and forgeability due to the addition of tin does not provide an effect commensurate with the amount added even if it exceeds 3.5% by weight, and is economically wasteful.
[0025]
  Phosphorus, as described above, uniformly disperses the γ phase and subdivides the α phase crystal grains in the matrix to improve the machinability as well as the corrosion resistance (dezincification corrosion resistance, pickling resistance). ), Exhibiting the function of improving forgeability, stress corrosion cracking resistance and mechanical strength. In the fifth invention alloy, the corrosion resistance and the like are improved by the function of phosphorus, and the machinability is improved mainly by the silicon addition effect. The effect of improving the corrosion resistance and the like by adding phosphorus is exhibited by adding a small amount of phosphorus, and is exhibited by adding 0.02% by weight or more. However, even if added over 0.25% by weight, not only an effect commensurate with the amount added is obtained, but also hot forgeability and extrudability are lowered.
[0026]
  Antimony and arsenic also improve dezincification corrosion resistance and the like in a trace amount (0.02% by weight or more), similarly to phosphorus. However, even if added over 0.15% by weight, not only an effect commensurate with the amount added is obtained, but also hot forgeability and extrudability are lowered as in the case of excessive addition of phosphorus.
[0027]
  For these reasons, in the fifth invention alloy, in addition to the same amount of copper, silicon and lead as in the first invention alloy, at least one of tin, phosphorus, antimony and arsenic is included in the above range as the corrosion resistance improving element. In addition to the machinability, corrosion resistance and the like can be improved. In the fifth invention alloy, tin and phosphorus mainly function as corrosion resistance improving elements similar to antimony and arsenic. Therefore, the first machinability improving element other than silicon and a small amount of lead is not added. Similar to the inventive alloy, the amounts of copper and silicon are 69 to 79% by weight and 2.0 to 4.0% by weight, respectively.
[0028]
  In the sixth invention, as a copper alloy having excellent machinability and corrosion resistance, 69 to 79% by weight of copper, 2.0 to 4.0% by weight of silicon, and 0.02 to 0.4% of lead. Selected from the group consisting of 0.3% to 3.5% by weight of tin, 0.02 to 0.25% by weight of phosphorus, 0.02 to 0.15% by weight of antimony, and 0.02 to 0.15% by weight of arsenic. And one or more elements selected from bismuth 0.02 to 0.4% by weight, tellurium 0.02 to 0.4% by weight and selenium 0.02 to 0.4% by weight. An alloy composition comprising zinc and the balance of zinc, and a metal structure including at least one of a γ phase and a κ phase,Excellent chip machinability, cutting resistance, and overall machinability of finishing roughness, with industrially satisfactory machinability.A free-cutting copper alloy (hereinafter referred to as “sixth invention alloy”) is proposed.
[0029]
  That is, the sixth invention alloy is any one of bismuth 0.02 to 0.4 wt%, tellurium 0.02 to 0.4 wt% and selenium 0.02 to 0.4 wt% with respect to the fifth invention alloy. In addition to improving the machinability by adding any one of bismuth, tellurium and selenium in addition to silicon and lead, as in the case of the second invention alloy, Similar to the fifth invention alloy, the corrosion resistance and the like are improved by adding at least one selected from tin, phosphorus, antimony and arsenic. Therefore, the addition amount of copper, silicon, lead, bismuth, tellurium and selenium was the same as that of the second invention alloy, and the addition amount of tin, phosphorus, antimony and arsenic was the same as that of the fifth invention alloy.
[0030]
  Further, in the seventh invention, as a copper alloy excellent in high strength and wear resistance in addition to machinability, copper 62-78% by weight, silicon 2.5-4.5% by weight, lead 0 0.02 to 0.4 wt%, one or more selected from tin 0.3 to 3.0 wt%, aluminum 0.2 to 2.5 wt% and phosphorus 0.02 to 0.25 wt% Containing an element and one or more elements selected from 0.7 to 3.5% by weight of manganese and 0.7 to 3.5% by weight of nickel, with the balance being made of zinc, A metal structure including at least one of γ phase and κ phase is formed,Excellent chip machinability, cutting resistance, and overall machinability of finishing roughness, with industrially satisfactory machinability.A free-cutting copper alloy (hereinafter referred to as “seventh invention alloy”) is proposed.
[0031]
  Manganese or nickel combines with silicon to form a fine intermetallic compound of MnX SiY or NiX SiY and precipitates uniformly in the matrix, thereby improving wear resistance and strength. Therefore, high strength and wear resistance are improved by adding one or both of manganese and nickel. Such an effect is exhibited by adding 0.7% by weight or more of manganese and nickel, respectively. However, even if added over 3.5% by weight, the effect becomes saturated and an effect commensurate with the amount added cannot be obtained. With the addition of manganese or nickel, silicon was added in an amount of 2.5 to 4.5% by weight in consideration of the amount of consumption required for forming an intermetallic compound with these.
[0032]
  Further, the addition of tin, aluminum and phosphorus enhances the α phase of the matrix and improves the machinability. Tin and phosphorus improve the strength and wear resistance by dispersing the α phase and γ phase, and also improve the machinability. Tin improves the strength and machinability by addition of 0.3% by weight or more, but if added over 3.0% by weight, ductility decreases. Therefore, in the 7th invention alloy which aims at improvement in high strength and abrasion resistance, the amount of tin added was set to 0.3 to 3.0% by weight in consideration of the machinability improving effect. Aluminum contributes to improvement of wear resistance, and the matrix strengthening function is exhibited by addition of 0.2% by weight or more. However, if it exceeds 2.5% by weight, the ductility decreases. Therefore, the amount of aluminum added is set to 0.2 to 2.5% by weight in consideration of the machinability improving effect. Further, the addition of phosphorus makes it possible to refine the α phase crystal grains in the matrix simultaneously with the dispersion of the γ phase, improve the hot workability, and improve the strength and wear resistance. In addition, there is an effect of remarkably improving the hot water flow during casting. Such an effect is exhibited by adding phosphorus in the range of 0.02 to 0.25% by weight. In addition, about the compounding quantity of copper, it was set to 62 to 78 weight% from the relationship with silicon addition amount, and the relationship from which manganese and nickel couple | bond with silicon.
[0033]
  Furthermore, in the eighth invention, as a copper alloy having excellent high temperature oxidation resistance in addition to machinability, copper 69 to 79% by weight, silicon 2.0 to 4.0% by weight, lead 0.02 to 0.0. 4% by weight, aluminum 0.1 to 1.5% by weight and phosphorus 0.02 to 0.25% by weight, the balance being zinc alloy composition, and at least one of γ phase and κ phase Including metallographic structure,Excellent chip machinability, cutting resistance, and overall machinability of finishing roughness, with industrially satisfactory machinability.A free-cutting copper alloy (hereinafter referred to as “eighth invention alloy”) is proposed.
[0034]
  Aluminum is an element that improves strength, machinability and wear resistance, as well as high-temperature oxidation resistance. In addition, as described above, silicon also improves machinability, strength, wear resistance, stress corrosion cracking resistance, and also functions to improve high-temperature oxidation resistance. Improvement of the high temperature oxidation resistance by aluminum is carried out by addition of 0.1% by weight or more by co-addition with silicon. However, even if aluminum is added in excess of 1.5% by weight, no effect of improving high-temperature oxidation resistance commensurate with the amount added is observed. From this point, the amount of aluminum added is 0.1 to 1.5% by weight.
[0035]
  Phosphorus is added in order to improve the hot water flow during alloy casting. In addition to such hot metal flow, phosphorus improves high-temperature oxidation resistance in addition to the machinability and dezincification corrosion resistance described above. Such an effect of adding phosphorus is exhibited at 0.02% by weight or more. However, even if added over 0.25% by weight, an effect commensurate with the added amount is not observed, and the brittleness of the alloy is caused instead. From this point, the amount of phosphorus added is 0.02 to 0.25% by weight.
[0036]
  Further, silicon is added to improve machinability as described above, and has a function of improving the hot water flowability similarly to phosphorus. The improvement of the hot water flow property by silicon is exhibited by the addition of 2.0% by weight or more, which overlaps with the addition range necessary for improving the machinability. Therefore, the amount of silicon added is set to 2.0 to 4.0% by weight in consideration of improvement of machinability.
[0037]
  In the ninth invention, as a copper alloy having excellent machinability and high-temperature oxidation resistance, 69 to 79% by weight of copper, 2.0 to 4.0% by weight of silicon, and 0.02 to 0 of lead. .4 wt%, aluminum 0.1-1.5 wt%, phosphorus 0.02-0.25 wt%, bismuth 0.02-0.4 wt%, tellurium 0.02-0.4 wt% 1 and an element selected from 0.02 to 0.4% by weight of selenium, and a metal structure containing at least one of a γ phase and a κ phase, and having an alloy composition with the balance being zinc None,Excellent chip machinability, cutting resistance, and overall machinability of finishing roughness, with industrially satisfactory machinability.A free-cutting copper alloy (hereinafter referred to as “ninth invention alloy”) is proposed.
[0038]
  That is, the ninth invention alloy further includes any one of bismuth 0.02 to 0.4 wt%, tellurium 0.02 to 0.4 wt% and selenium 0.02 to 0.4 wt% to the eighth invention alloy. The alloy composition is contained, and by adding bismuth, which is an element that improves machinability similar to lead as described above, while ensuring high-temperature oxidation resistance similar to that of the eighth invention alloy, This is a further improvement of machinability.
[0039]
  In the tenth invention, as a copper alloy having excellent machinability and high-temperature oxidation resistance, 69 to 79% by weight of copper, 2.0 to 4.0% by weight of silicon, and 0.02 to 0 of lead. .4 wt%, aluminum 0.1-1.5 wt%, phosphorus 0.02-0.25 wt%, chromium 0.02-0.4 wt% and titanium 0.02-0.4 wt% 1 and at least one element selected from the group consisting of zinc and the balance comprising zinc, and a metal structure including at least one of γ phase and κ phase,Excellent chip machinability, cutting resistance, and overall machinability of finishing roughness, with industrially satisfactory machinability.A free-cutting copper alloy (hereinafter referred to as “tenth invention alloy”) is proposed.
[0040]
  Chromium and titanium have a function of improving high-temperature oxidation resistance, and the function is remarkably exhibited particularly by a synergistic effect by co-addition with aluminum. Such functions are exhibited at 0.02% by weight or more, and become saturated at 0.4% by weight, regardless of whether these are added alone or together. From this point, in the 10th invention alloy, the 8th alloy further contains at least one of 0.02 to 0.4 wt% chromium and 0.02 to 0.4 wt% titanium. In order to further improve the high temperature oxidation resistance of the alloy of the eighth invention.
[0041]
In the eleventh aspect of the invention, as a copper alloy having excellent machinability and high-temperature oxidation resistance, 69 to 79% by weight of copper, 2.0 to 4.0% by weight of silicon, and 0.02 to 0 of lead. .4 wt%, aluminum 0.1-1.5 wt%, phosphorus 0.02-0.25 wt%, chromium 0.02-0.4 wt% and titanium 0.02-0.4 wt% At least one element selected from the group consisting of 0.02 to 0.4% by weight of bismuth, 0.02 to 0.4% by weight of tellurium, and 0.02 to 0.4% by weight of selenium. And an alloy composition including the balance of zinc, and a metal structure including at least one of a γ phase and a κ phase,Excellent chip machinability, cutting resistance, and overall machinability of finishing roughness, with industrially satisfactory machinability.A free-cutting copper alloy (hereinafter referred to as “11th invention alloy”) is proposed.
[0042]
  That is, the eleventh invention alloy is any one of 0.02 to 0.4% by weight of bismuth, 0.02 to 0.4% by weight of tellurium and 0.02 to 0.4% by weight of selenium. As described above, by adding bismuth, which is an element similar to lead, which improves machinability by a function different from silicon as described above, high temperature oxidation resistance similar to that of the 10th invention alloy is added. It is intended to further improve the machinability while securing the properties.
[0043]
  In the twelfth invention, each of the above-described alloys is subjected to a heat treatment at 400 to 600 ° C. for 30 minutes to 5 hours,By finely dispersing and precipitating the γ phase,A free-cutting copper alloy (hereinafter referred to as “the 12th invention alloy”) with further improved machinability is proposed.
[0044]
  The first to eleventh invention alloys are added with machinability improving elements such as silicon and have excellent machinability by addition of such elements, but machinability by the function of such additional elements is It may be further improved by heat treatment. For example, in the first to eleventh invention alloys with high copper concentration, with a small amount of γ phase and a large amount of κ phase, the κ phase is changed to γ phase by heat treatment, and the γ phase is finely dispersed. The machinability is further improved by the precipitation. In addition, assuming the production of actual castings, wrought materials, and hot forgings, depending on conditions such as casting conditions, productivity after hot working (hot extrusion, hot forging, etc.), working environment, etc. The material may be forced air-cooled or water-cooled. In such a case, in the first to eleventh invention alloys, particularly those having a low copper concentration, the γ phase is slightly less and the β phase is included. However, when heat treatment is performed, the β phase changes to the γ phase. At the same time, the γ phase is finely dispersed and precipitated, thereby improving machinability. However, in any case, if the heat treatment temperature is less than 400 ° C., the above-described phase change rate becomes slow, and the heat treatment takes an extremely long time, so that it cannot be used economically. On the other hand, when the temperature exceeds 600 ° C., the κ phase increases or the β phase appears, so that the machinability improving effect cannot be obtained. Therefore, in consideration of practicality, it is preferable to perform heat treatment for 30 minutes to 5 hours at 400 to 600 ° C. in order to improve machinability.
[0045]
【Example】
  As an example, an ingot having a composition shown in Tables 1 to 15 (a cylindrical shape having an outer diameter of 100 mm and a length of 150 mm) is extruded into a round bar shape having an outer diameter of 15 mm hot (750 ° C.). 1 invention alloy no. 1001-No. 1007, second invention alloy no. 2001-No. 2006, third invention alloy no. 3001-No. 3010, 4th invention alloy no. 4001-No. 4021, fifth invention alloy no. 5001-No. 5020, 6th invention alloy no. 6001-No. 6045, 7th invention alloy no. 7001-No. 7029, 8th invention alloy no. 8001-No. 8008, ninth invention alloy no. 9001-No. 9006, 10th invention alloy no. 10001-No. 10008 and 11th invention alloy no. 11001-No. 11011 was obtained. Further, an ingot having a composition shown in Table 16 (cylindrical shape having an outer diameter of 100 mm and a length of 150 mm) was extruded into a round bar shape having an outer diameter of 15 mm hot (750 ° C.). The twelfth invention alloy no. 12001-No. 12004 was obtained. That is, no. 12001 is alloy No. 1 of the first invention. An extruded material having the same composition as that of No. 1006 was heat-treated at 580 ° C. for 30 minutes. No. 12002 is No. An extruded material having the same composition as that of No. 1006 was heat-treated at 450 ° C. for 2 hours. 12003 is alloy No. 1 of the first invention. Extruded material having the same composition as that of No. 1007 is No. 1007. It was heat-treated under the same conditions (580 ° C., 30 minutes) as No. 12001. No. 12004 is No. Extruded material having the same composition as that of No. 1007 is No. 1007. Heat-treated under the same condition as that of 12002 (450 ° C., 2 hours).
[0046]
  Further, as a comparative example, an ingot having a composition shown in Table 17 (a cylindrical shape having an outer diameter of 100 mm and a length of 150 mm) is extruded hot (750 ° C.) to obtain a round bar-shaped extruded material having an outer diameter of 15 mm ( Hereinafter referred to as “conventional alloy”) 13001-No. 13006 was obtained. No. 13001 corresponds to “JIS C3604”. 13002 corresponds to “CDA C36000”. 13003 corresponds to “JIS C3771”. 13004 corresponds to “CDA C69800”. No. 13005 corresponds to “JIS C6191”, and is the aluminum bronze that is the most excellent in strength and wear resistance among the copper products specified in JIS. No. 13006 corresponds to “JIS C4622” and is Naval brass having the highest corrosion resistance among the copper products specified in JIS.
[0047]
[Table 1]

[0048]
[Table 2]

[0049]
[Table 3]

[0050]
[Table 4]

[0051]
[Table 5]

[0052]
[Table 6]

[0053]
[Table 7]

[0054]
[Table 8]

[0055]
[Table 9]

[0056]
[Table 10]

[0057]
[Table 11]

[0058]
[Table 12]

[0059]
[Table 13]

[0060]
[Table 14]

[0061]
[Table 15]

[0062]
[Table 16]

[0063]
[Table 17]

[0064]
  Then, in order to confirm the machinability of the first to twelfth invention alloys in comparison with the conventional alloys, the following cutting test was performed, and the cutting main component force, the chip state and the cutting surface form were determined.
[0065]
  That is, the outer peripheral surface of each extruded material obtained as described above was cut at a cutting speed of 50 m / min and a cutting depth (cutting allowance): 1 with a lathe equipped with a serious tool (rake angle: −8 °). .5 mm, feed amount: 0.11 mm / rev. The signal from the three-component dynamometer attached to the cutting tool was converted into a voltage signal by a heavy strain measuring instrument and recorded by a recorder, and this was converted into cutting resistance. By the way, the magnitude of the cutting force is determined by the three component forces, that is, the main component force, the feed component force, and the back component force. Here, the cutting force has the main component force (N) showing the largest value among the three component forces. It was decided to judge the size. The results were as shown in Table 18 to Table 33.
[0066]
  Moreover, the state of the chip | tip produced | generated by cutting was observed, and it classified into four as shown to FIG. 1 (A)-(D) according to the shape, and showed to Table 1-Table 15. FIG. By the way, as shown in FIG. (D), when the chip has a spiral shape of three or more turns, it becomes difficult to process the chip (chip collection and reuse, etc.), and the chip is entangled with the bite. Or troubles such as damage to the cutting surface occur, and good cutting cannot be performed. In addition, as shown in FIG. (C), when the chip has a spiral shape of about 2 turns from an arc shape of about half turns, a big trouble occurs when the spiral shape is made of 3 turns or more. Although there is not, processing of chips is still not easy, and there is a risk of entanglement of the cutting tool, damage to the cutting surface, etc. when continuous cutting is performed. However, when the chips are sheared into a fine needle-shaped piece such as (A) or a fan-shaped piece or arc-shaped piece such as (B), the above-described trouble does not occur, and (C) Since it is not bulky like what is shown to a figure and (D) figure, the process of a chip is also easy. However, when the chips are sheared into a fine shape as shown in FIG. (A), they may sink into the sliding surface of a machine tool such as a lathe to cause a mechanical failure or get stuck in an operator's fingers or eyes. May be accompanied by danger. Therefore, in determining machinability, the one shown in FIG. (B) is the best, the one shown in FIG. (A) follows, and the one shown in FIG. (C) and (D) is inappropriate. It is considerable. In Table 18 to Table 33, the best chip state shown in (B) was observed with “◎”, and (A) the slightly good chip state shown in FIG. (C) The case where the bad chip state shown in the figure was observed was indicated by “Δ”, and the case where the worst chip state shown in (D) was observed was indicated by “x”.
[0067]
  Moreover, after cutting, the quality of the cut surface was determined by the surface roughness. The results were as shown in Table 18 to Table 33. By the way, the maximum height (Rmax) is often used as a standard for surface roughness, and although it depends on the application of the brass product, it is generally judged that if Rmax <10 μm, the machinability is extremely excellent. If it is 10 μm ≦ Rmax <15 μm, it can be judged that industrially satisfactory machinability could be obtained, and if Rmax ≧ 15 μm, it can be judged that the machinability is inferior. In Tables 18 to 33, the case of Rmax <10 μm is indicated by “◯”, the case of 10 μm ≦ Rmax <15 μm is indicated by “Δ”, and the case of Rmax ≧ 15 μm is indicated by “X”.
[0068]
  As apparent from the results of the cutting tests shown in Table 18 to Table 33, the first invention alloy No. 1001-No. 1007, second invention alloy no. 2001-No. 2006, third invention alloy no. 3001-No. 3010, 4th invention alloy no. 4001-No. 4021, fifth invention alloy no. 5001-No. 5020, 6th invention alloy no. 6001-No. 6045, 7th invention alloy no. 7001-No. 7029, 8th invention alloy no. 8001-No. 8008, ninth invention alloy no. 9001-No. 9006, 10th invention alloy no. 10001-No. 10008, 11th invention alloy no. 11001-No. 11011 and 12th invention alloy no. 12001-No. No. 12004 is a conventional alloy No. 1 containing a large amount of lead. 13001-No. It has machinability equivalent to 13003. In particular, as far as the chip generation state is concerned, the conventional alloy no. 13004-No. Of course, compared with 13006, the conventional alloy No. 1 containing a large amount of lead is used. 13001-No. Compared to 13003, it has good machinability. In addition, the first invention alloy No. 1006 and no. In comparison with No. 1007, the alloy No. 12 of the 12th invention in which this was heat-treated. 12001-No. It is understood that 12004 has machinability equal to or higher than that, and depending on conditions such as the alloy composition, the machinability of the first to eleventh invention alloys can be further improved by heat treatment.
[0069]
  Next, in order to confirm the hot workability and mechanical properties of the first to twelfth invention alloys in comparison with the conventional alloys, the following hot compression test and tensile test were performed.
[0070]
  That is, first and second test pieces having the same shape (outer diameter: 15 mm, length: 25 mm) were cut out from the extruded materials obtained as described above. In the hot compression test, each first test piece is heated to 700 ° C. and held for 30 minutes, and then compressed in the axial direction at a compression rate of 70% (the height (length) of the first test piece is The surface morphology after compression (700 ° C. deformability) was visually determined. The results were as shown in Table 18 to Table 33. Judgment of the deformability is made visually from the state of cracks on the side of the test piece. In Tables 18 to 33, “◯” indicates that no cracks have occurred, and “Δ” indicates that small cracks have occurred. Those with large cracks are indicated by “x”. In addition, each second test piece was used to conduct a tensile test by a conventional method, and the tensile strength (N / mm²) And elongation (%).
[0071]
  From the results of the hot compression test and the tensile test shown in Table 18 to Table 33, the first to twelfth invention alloys are the conventional alloy Nos. 13001-No. 13004 and no. It has been confirmed that it has hot workability and mechanical properties equivalent to or higher than 13006, and can be used industrially. In particular, with regard to the seventh invention alloy, the conventional alloy No. 1 which is aluminum bronze having the highest strength among the drawn copper products specified in JIS. It is understood that it has mechanical properties equivalent to 13005 and is excellent in high strength.
[0072]
  In addition, in order to confirm the corrosion resistance and stress corrosion cracking resistance of the first to sixth invention alloys and the eighth to twelfth invention alloys in comparison with the conventional alloys, the dezincification corrosion test by the method defined in “ISO 6509”. And a stress corrosion cracking test specified in “JIS H3250”.
[0073]
  That is, in the dezincification corrosion test of “ISO 6509”, a sample collected from each extruded material is embedded in a phenol resin material so that the exposed sample surface is perpendicular to the extrusion direction of the extruded material. Was polished to number 1200 with emery paper, and then this was ultrasonically washed in pure water and dried. The corrosion test sample thus obtained was added to 1.0% cupric chloride dihydrate (CuCl2 · 2H).₂O) is immersed in an aqueous solution (12.7 g / l) and kept at a temperature of 75 ° C. for 24 hours, and then taken out from the aqueous solution to obtain a maximum dezincification corrosion depth (maximum dezincification corrosion depth). Measured). The results were as shown in Tables 18 to 25 and Tables 28 to 33.
[0074]
  As understood from the results of the dezincification corrosion test shown in Table 18 to Table 25 and Table 28 to Table 33, the first to fourth invention alloys and the eighth to twelfth invention alloys are conventional containing a large amount of lead. Alloy No. 13001-No. It has excellent corrosion resistance compared to 13003, and in particular, the fifth and sixth invention alloys that improve the corrosion resistance as well as the machinability have the highest corrosion resistance among the copper products specified in JIS. Conventional alloy No. which is the most excellent naval brass. It was confirmed that it has extremely excellent corrosion resistance even when compared with 13006.
[0075]
  Further, in the stress corrosion cracking test of “JIS H3250”, a sample having a length of 150 mm is cut out from each extruded material, and each sample is placed at one end thereof in a state where its central portion is applied to an arc-shaped jig having a radius of 40 mm. Was bent at 45 ° with respect to the other end to obtain a test piece. Each test piece to which tensile residual stress was added in this manner was degreased and dried, and then the ammonia atmosphere in a desiccator containing 12.5% ammonia water (ammonia diluted with an equal amount of pure water). (25 ° C.). That is, each test piece is held at a position approximately 80 mm above the ammonia water surface in the desiccator. Then, when the holding time of the test piece in the ammonia atmosphere has passed 2 hours, 8 hours, and 24 hours, the test piece is taken out from the desiccator and washed with 10% sulfuric acid. The presence or absence was visually confirmed with a magnifying glass (magnification: 10 times). The results were as shown in Tables 18 to 25 and Tables 28 to 33. In these tables, when the retention time in the ammonia atmosphere was 2 hours, the crack was recognized as “XX”, and no crack was observed after 2 hours. For those where clear cracks were observed after 8 hours, the test was “x”. No cracks were observed after 8 hours, but clear cracks were observed after 24 hours. “△” indicates that no crack was observed even after 24 hours, and “◯” indicates.
[0076]
  As understood from the results of the stress corrosion cracking test shown in Table 18 to Table 25 and Table 28 to Table 33, the alloys of the fifth and sixth inventions aiming at improving the corrosion resistance as well as the machinability are of course corrosion resistance. As for the first to fourth invention alloys and the eighth to twelfth invention alloys that are not specially considered, the conventional alloy No. 1 that is aluminum bronze containing no zinc is also used. Conventional alloy No. 23, which is Naval brass, which has the same stress corrosion cracking resistance as 13005 and has the highest corrosion resistance among the copper products specified in JIS. It was confirmed that the material has stress corrosion cracking resistance superior to 13006.
[0077]
  Further, the following oxidation test was conducted in order to confirm the high temperature oxidation resistance of the eighth to eleventh invention alloys in comparison with the conventional alloys.
[0078]
  That is, each extruded material No. 8001-No. 8008, no. 9001-No. 9006, no. 10001-No. 10008, no. 11001-No. 11011 and no. From 13001 to 13006, round bar-shaped test pieces that were surface-ground to an outer diameter of 14 mm and cut to a length of 30 mm were obtained, and the weight of each test piece (hereinafter referred to as “pre-oxidation weight”) was measured. . Thereafter, each test piece was left in an electric furnace maintained at 500 ° C. while being stored in a magnetic crucible. Then, after the standing time has passed 100 hours, it is taken out from the electric furnace, the weight of each test piece (hereinafter referred to as “weight after oxidation”) is measured, and the increase in oxidation is calculated from the weight before oxidation and the weight after oxidation. did. Here, the increase in oxidation means the degree of weight increase (mg) due to oxidation per 10 cm @ 2 of the surface area of the test piece. "Oxidation increase (mg / 10 cm @ 2) = (weight after oxidation (mg) -weight before oxidation". (Mg)) x (10 cm²/ Surface area of specimen (cm²) ". That is, the weight after oxidation of each test piece is higher than the weight before oxidation, which is due to high temperature oxidation. In other words, when exposed to high temperatures, oxygen and copper, zinc, silicon combine to form Cu2O, ZnO, SiO.²Thus, the weight increases due to the increment of oxygen. Therefore, it can be said that the smaller the degree of weight increase (oxidation increase), the better the high-temperature oxidation resistance, and the results shown in Tables 28 to 31 and Table 33 were obtained.
[0079]
  As is apparent from the results of the oxidation tests shown in Tables 23 to 31 and Table 33, the increase in oxidation of the eighth to eleventh invention alloys has a high degree of high-temperature oxidation resistance among the rolled copper products specified in JIS. Conventional alloy No. 1 which is aluminum bronze. It is equivalent to 13005 and is much smaller than other conventional alloys. Accordingly, it was confirmed that the eighth to eleventh invention alloys were extremely excellent in high-temperature oxidation resistance in addition to machinability.
[0080]
[Table 18]

[0081]
[Table 19]

[0082]
[Table 20]

[0083]
[Table 21]

[0084]
[Table 22]

[0085]
[Table 23]

[0086]
[Table 24]

[0087]
[Table 25]

[0088]
[Table 26]

[0089]
[Table 27]

[0090]
[Table 28]

[0091]
[Table 29]

[0092]
[Table 30]

[0093]
[Table 31]

[0094]
[Table 32]

[0095]
[Table 33]

[0096]
  Further, as a second example, an ingot having a composition shown in Tables 9 to 11 (a cylindrical shape having an outer diameter of 100 mm and a length of 200 mm) is hot (700 ° C.) extruded into a round bar shape having an outer diameter of 35 mm. The seventh invention alloy no. 7001a-No. 7029a was obtained. As a second comparative example, an ingot having a composition shown in Table 17 (a cylindrical shape having an outer diameter of 100 mm and a length of 200 mm) is extruded hot (700 ° C.) to form a round bar shape having an outer diameter of 35 mm. Extruded material (hereinafter referred to as “conventional alloy”) No. 13001a-No. 13006a was obtained. No. 7001a-No. 7029a and no. 13001a-No. 13006a is the above-described copper alloy no. 7001-No. 7029 and no. 13001-No. It has the same alloy composition as 13006.
[0097]
  And, the seventh invention alloy No. 7001a-No. The wear resistance of 7029a is the same as that of the conventional alloy no. 13001a-No. In order to confirm in comparison with 13006a, the following wear test was performed.
[0098]
  That is, by cutting the outer peripheral surface of each extruded material obtained as described above, and performing drilling and cutting, a ring shape having an outer diameter of 32 mm and a thickness (length in the axial direction) of 10 mm. After obtaining the test pieces, each test piece is fitted and fixed to a rotatable shaft, and a 50-mm SUS304 roll having an outer diameter of 48 mm is placed in parallel with the axis and held in a pressure contact state. Let Thereafter, the roll made of SUS304 and the test piece that is in rolling contact with the roll are rotated at the same rotational speed (209 rpm) while dropping multi-oil on the outer peripheral surface of the test piece. And when the rotation speed of the said test piece reached | attained 100,000 times, rotation of the roll made from SUS304 and a test piece was stopped, and the weight difference before the rotation of each test piece, ie, abrasion loss (mg), was measured. It can be said that the smaller the weight loss, the better the copper alloy, but the results are as shown in Table 34 to Table 36.
[0099]
  As apparent from the results of the wear tests shown in Table 34 to Table 36, the seventh invention alloy No. 7001a-No. 7029a is a conventional alloy no. 13001-No. 13004 and no. Of course, compared with 13006, the conventional alloy No. 1 which is aluminum bronze which is the most excellent in wear resistance among the drawn copper products specified in JIS. Even when compared with 13005, it was confirmed that the wear resistance was excellent. Therefore, when comprehensively considering the results of the tensile test described above, in addition to machinability, the seventh invention alloy has the highest wear resistance among the copper products specified in JIS. It can be said that it has high strength and wear resistance equivalent to or better than excellent aluminum bronze.
[0100]
[Table 34]

[0101]
[Table 35]

[0102]
[Table 36]

[0103]
【The invention's effect】
  As can be easily understood from the above explanation, the first to twelfth invention alloys have a very small amount (0.02 to 0.4 wt%) of lead as a machinability improving element. Nevertheless, it is extremely machinable and can be safely used as an alternative to conventional free-cutting copper alloys containing a large amount of lead. It is possible to cope with the recent trend that lead-containing products are being regulated.
[0104]
  Furthermore, the fifth and sixth invention alloys are excellent in corrosion resistance in addition to machinability, and are processed products, forged products, cast products, etc. that require corrosion resistance (for example, water taps, water supply / drainage fittings) , Valves, stems, hot water supply pipe parts, shafts, heat exchanger parts, etc.), and their practical value is extremely great.
[0105]
  In addition to machinability, the seventh invention alloy is excellent in high strength and wear resistance. Cutting products, forged products, cast products, etc. that require high strength and wear resistance ( For example, it can be suitably used as a constituent material of bearings, bolts, nuts, bushes, gears, sewing machine parts, hydraulic parts, etc., and its practical value is extremely large.
[0106]
  Further, the eighth to eleventh invention alloys are excellent in high temperature oxidation resistance in addition to machinability, and are processed products, forged products, cast products, etc. that require high temperature oxidation resistance (for example, petroleum -A gas warm air heater nozzle, burner head, water heater gas nozzle, etc.) can be suitably used as a constituent material, and its practical value is extremely large.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a form of chips.

Claims

The alloy composition contains 69 to 79% by weight of copper, 2.0 to 4.0% by weight of silicon and 0.02 to 0.4% by weight of lead, and the balance is made of zinc. A free-cutting copper alloy having a metal structure including at least one of κ phases and having a machinability that is sufficiently satisfactory industrially .

69-79 wt% copper, 2.0-4.0 wt% silicon, 0.02-0.4 wt% lead, 0.02-0.4 wt% bismuth, 0.02-0. A metal containing 4% by weight and one element selected from 0.02 to 0.4% by weight of selenium and having the balance of zinc and the balance of at least one of γ phase and κ phase A free-cutting copper alloy having a structure and having machinability that can be sufficiently satisfied industrially .

70-80% by weight of copper, 1.8-3.5% by weight of silicon, 0.02-0.4% by weight of lead, 0.3-3.5% by weight of tin, 1.0-3. 5% by weight and one or more elements selected from 0.02 to 0.25% by weight of phosphorus, the balance being an alloy composition made of zinc, and including at least one of γ phase and κ phase A free-cutting copper alloy characterized by having a metallographic structure and machinability that can be sufficiently satisfied industrially .

70-80% by weight of copper, 1.8-3.5% by weight of silicon, 0.02-0.4% by weight of lead, 0.3-3.5% by weight of tin, 1.0-3. One or more elements selected from 5 wt% and phosphorus 0.02 to 0.25 wt%, bismuth 0.02 to 0.4 wt%, tellurium 0.02 to 0.4 wt% and selenium An alloy composition containing one element selected from 02 to 0.4% by weight and the balance being zinc , and having a metal structure including at least one of a γ phase and a κ phase , industrially A free-cutting copper alloy having a machinability that can be satisfactorily satisfied .

69-79 wt% copper, 2.0-4.0 wt% silicon, 0.02-0.4 wt% lead, 0.3-3.5 wt% tin, 0.02-0. And containing at least one element selected from 25% by weight, antimony 0.02 to 0.15% by weight, and arsenic 0.02 to 0.15% by weight, with the balance being zinc. A free-cutting copper alloy characterized by having a metal structure containing at least one of a γ phase and a κ phase, and having a machinability sufficiently industrially satisfactory .

69-79 wt% copper, 2.0-4.0 wt% silicon, 0.02-0.4 wt% lead, 0.3-3.5 wt% tin, 0.02-0. One or more elements selected from 25% by weight, antimony 0.02-0.15% by weight and arsenic 0.02-0.15% by weight, bismuth 0.02-0.4% by weight, tellurium One element selected from 02 to 0.4% by weight and 0.02 to 0.4% by weight of selenium , and the balance is made of an alloy composed of zinc, and at least of γ phase and κ phase A free-cutting copper alloy characterized by having a metallographic structure including one and having industrially satisfactory machinability .

Copper 62-78 wt%, silicon 2.5-4.5 wt%, lead 0.02-0.4 wt%, tin 0.3-3.0 wt%, aluminum 0.2-2. One or more elements selected from 5% by weight and phosphorous from 0.02 to 0.25% by weight and selected from manganese from 0.7 to 3.5% by weight and nickel from 0.7 to 3.5% by weight contains the one or more elements, and with the balance constituting the alloy composition consisting of zinc, to name a metal structure including at least one of γ-phase and κ phase, comprising a machinability that can industrially satisfactory A free-cutting copper alloy characterized by

69-79 wt% copper, 2.0-4.0 wt% silicon, 0.02-0.4 wt% lead, 0.1-1.5 wt% aluminum, 0.02-0 phosphorus .25 containing wt%, and with the balance constituting the alloy composition consisting of zinc, to name a metal structure including at least one of γ-phase and κ phase, comprising a machinability that can industrially satisfactory free-cutting copper alloy, characterized in that.

69-79 wt% copper, 2.0-4.0 wt% silicon, 0.02-0.4 wt% lead, 0.1-1.5 wt% aluminum , 0.02-0 phosphorus .25 wt% and one element selected from 0.02 to 0.4 wt% bismuth, 0.02 to 0.4 wt% tellurium and 0.02 to 0.4 wt% selenium. And a free-cutting copper characterized by having a metal structure including at least one of a γ-phase and a κ-phase, and having a machinability sufficiently industrially satisfactory, having an alloy composition with the balance being zinc. alloy.

69-79 wt% copper, 2.0-4.0 wt% silicon, 0.02-0.4 wt% lead, 0.1-1.5 wt% aluminum, 0.02-0 phosphorus An alloy composition containing 25% by weight, one or more elements selected from 0.02 to 0.4% by weight of chromium and 0.02 to 0.4% by weight of titanium, with the balance being zinc. with eggplant, to name a metal structure including at least one of γ-phase and κ-phase, free-cutting copper alloy which is characterized by comprising a machinability that can industrially satisfactory.

69-79 wt% copper, 2.0-4.0 wt% silicon, 0.02-0.4 wt% lead, 0.1-1.5 wt% aluminum , 0.02-0 phosphorus .25 wt%, one or more elements selected from chromium 0.02-0.4 wt% and titanium 0.02-0.4 wt%, bismuth 0.02-0.4 wt%, tellurium And an element composition selected from 0.02 to 0.4% by weight and selenium 0.02 to 0.4% by weight and the balance being zinc, and a γ phase and a κ phase A free-cutting copper alloy characterized by having a metallographic structure including at least one of the above and having machinability sufficiently industrially satisfactory .

The heat treatment is carried out at 400 to 600 ° C. for 30 minutes to 5 hours to finely disperse and precipitate the γ phase, wherein claim 1, claim 2, claim 3, claim 4, claim 5 and claim 6. The free-cutting copper alloy according to claim 7 , claim 8, claim 9, claim 10, or claim 11 .