JP4120442B2

JP4120442B2 - Cutting tool made of surface-coated cemented carbide that exhibits excellent wear resistance of hard coating layer under high-speed cutting conditions and method for manufacturing the same

Info

Publication number: JP4120442B2
Application number: JP2003100067A
Authority: JP
Inventors: 和則佐藤; 裕介田中
Original assignee: Mitsubishi Materials Corp
Current assignee: Mitsubishi Materials Corp
Priority date: 2003-04-03
Filing date: 2003-04-03
Publication date: 2008-07-16
Anticipated expiration: 2023-04-03
Also published as: JP2004306166A

Description

【０００１】
【発明の属する技術分野】
この発明は、硬質被覆層がすぐれた高温強度を有し、かつ高温硬さと耐熱性にもすぐれ、したがって例えば粘性の高い各種のステンレス鋼や軟鋼などの難削材の切削加工を、特に高い発熱を伴う高速加工条件で行なった場合に、硬質被覆層がすぐれた耐摩耗性を発揮する表面被覆超硬合金製切削工具（以下、被覆超硬工具という）およびその製造方法に関するものである。
【０００２】
【従来の技術】
一般に、被覆超硬工具には、各種の鋼や鋳鉄などの被削材の旋削加工や平削り加工にバイトの先端部に着脱自在に取り付けて用いられるスローアウエイチップ、前記被削材の穴あけ切削加工などに用いられるドリルやミニチュアドリル、さらに前記被削材の面削加工や溝加工、肩加工などに用いられるソリッドタイプのエンドミルなどがあり、また前記スローアウエイチップを着脱自在に取り付けて前記ソリッドタイプのエンドミルと同様に切削加工を行うスローアウエイエンドミル工具などが知られている。
【０００３】
また、被覆超硬工具として、炭化タングステン（以下、ＷＣで示す）基超硬合金の超硬基体または炭窒化チタン（以下、ＴｉＣＮで示す）基サーメットの超硬基体（以下、これらの超硬基体を総称して「超硬基体」という）の表面に、組成式：［Ｔｉ_1-(Y+Z)Ａｌ_YＳｉ_Z）Ｎ］（ただし、原子比で、Ｙは０．３５〜０．６５、Ｚは０．０１〜０．１０を示す）を満足するＴｉとＡｌとＳｉの複合窒化物［以下、（Ｔｉ，Ａｌ，Ｓｉ）Ｎで示す］層からなる硬質被覆層を１〜１５μｍの平均層厚で物理蒸着してなる被覆超硬工具が提案され、かかる被覆超硬工具が、硬質被覆層を構成する前記（Ｔｉ，Ａｌ，Ｓｉ）Ｎ層がＡｌ成分による高温硬さと耐熱性、およびＴｉ成分による強度を有し、さらにＳｉ成分による一段の耐熱性向上と相俟って、高熱発生を伴う各種の鋼や鋳鉄などの連続切削や断続切削加工に用いられることも知られている（例えば特許文献１参照）。
【０００４】
さらに、上記の被覆超硬工具が、例えば図２に概略説明図で示される物理蒸着装置の１種であるアークイオンプレーティング装置に上記の超硬基体を装入し、ヒータで装置内を、例えば５００℃の温度に加熱した状態で、アノード電極と所定組成を有するＴｉ−Ａｌ−Ｓｉ合金がセットされたカソード電極（蒸発源）との間に、例えば電流：９０Ａの条件でアーク放電を発生させ、同時に装置内に反応ガスとして窒素ガスを導入して、例えば２Ｐａの反応雰囲気とし、一方上記超硬基体には、例えば−１００Ｖのバイアス電圧を印加した条件で、前記超硬基体の表面に、上記（Ｔｉ，Ａｌ，Ｓｉ）Ｎ層からなる硬質被覆層を蒸着することにより製造されることも良く知られるところである。（例えば、特許文献１参照）。
【０００５】
【特許文献１】
特許第２７９３７７３号公報
【０００６】
【発明が解決しようとする課題】
近年の切削加工装置の高性能化はめざましく、一方で切削加工に対する省力化および省エネ化、さらに低コスト化の要求は強く、これに伴い、一段と高速化した条件での切削加工を強いられる傾向にあるが、上記の従来被覆超硬工具においては、これを例えば粘性の高い各種のステンレス鋼や軟鋼などの難削材の切削加工を、特に高い発熱を伴う高速条件で行なうのに用いた場合、硬質被覆層である（Ｔｉ，Ａｌ，Ｓｉ）Ｎ層の高温硬さおよび耐熱性不足原因で、切刃部のすくい面と逃げ面の交わる切刃稜線部に熱塑性変形が発生し、この結果前記硬質被覆層の摩耗進行が一段と促進されるようになることから、比較的短時間で使用寿命に至るのが現状である。
【０００７】
【課題を解決するための手段】
そこで、本発明者等は、上述のような観点から、特に上記の従来被覆超硬工具の硬質被覆層に着目し、特に粘性の高い各種のステンレス鋼や軟鋼などの難削材の高速切削で切刃稜線部に熱塑性変形の発生なく、すぐれた耐摩耗性を発揮する硬質被覆層を開発すべく、研究を行った結果、
（ａ）例えば図１（ａ）に概略平面図で、同（ｂ）に概略正面図で示される構造の物理蒸着装置に属するアークイオンプレーティング装置、すなわち装置中央部に超硬基体装着用回転テーブルを設け、前記回転テーブルを挟んで、一方側に相対的にＡｌ含有割合の高いＡｌ−Ｔｉ−Ｓｉ合金、他方側に相対的にＴｉ含有割合の高いＴｉ−Ａｌ−Ｓｉ合金をいずれもカソード電極（蒸発源）として対向配置し、さらにいずれも前記Ａｌ−Ｔｉ−Ｓｉ合金に比してＡｌ含有割合が低く、かつ前記Ｔｉ−Ａｌ−Ｓｉ合金に比してＴｉ含有割合が低い中間Ａｌ／Ｔｉ／Ｓｉ合金と中間Ｔｉ／Ａｌ／Ｓｉ合金を同じくカソード電極（蒸発源）として対向配置したアークイオンプレーティング装置を用い、
この装置の前記回転テーブル上に、前記回転テーブルの中心軸から半径方向に離れた位置に偏心して前記超硬基体を装着し、
この状態で装置内の反応雰囲気を酸素と窒素の混合雰囲気とするが、前記酸素と窒素の装置内への相対導入割合を上記超硬基体の回転移動位置に対応して調整して、前記超硬基体が上記の相対的にＡｌ含有割合の高いＡｌ−Ｔｉ−Ｓｉ合金のカソード電極に最も接近した時点での反応雰囲気を酸素導入割合が最も高く、窒素導入割合が最も低い、望ましくは酸素の相対導入割合が９０〜９７容量％で、残りが窒素からなる反応雰囲気とする一方、前記超硬基体が上記の相対的にＴｉ含有割合の高いＴｉ−Ａｌ−Ｓｉ合金のカソード電極に最も接近した時点での反応雰囲気を窒素導入割合が最も高く、酸素導入割合が最も低い、望ましくは窒素の相対導入割合が９０〜９７容量％で、残りが酸素からなる反応雰囲気とすると共に、前記超硬基体が前記Ａｌ−Ｔｉ−Ｓｉ合金のカソード電極最接近位置から上記中間Ａｌ／Ｔｉ／Ｓｉ合金のカソード電極最接近位置を経て前記Ｔｉ−Ａｌ−Ｓｉ合金のカソード電極最接近位置に回転移動する間の反応雰囲気を、酸素の導入割合を連続的に減少させ、これに対応して窒素の導入割合を連続的に増加させる連続変化雰囲気とし、一方前記超硬基体が前記Ｔｉ−Ａｌ−Ｓｉ合金のカソード電極最接近位置から上記中間Ｔｉ／Ａｌ／Ｓｉ合金のカソード電極最接近位置を経て前記Ａｌ−Ｔｉ−Ｓｉ合金のカソード電極最接近位置に回転移動する間の反応雰囲気を、窒素の導入割合を連続的に減少させ、これに対応して酸素の導入割合を連続的に増加させる連続変化雰囲気とし、
上記回転テーブルを回転させると共に、蒸着形成される硬質被覆層の層厚均一化を図る目的で前記超硬基体自体も自転させながら、前記のそれぞれのカソード電極（蒸発源）とアノード電極との間にアーク放電を発生させる条件で、
ＡｌとＴｉとＳｉの複合酸窒化物（以下、Ａｌ−Ｔｉ−Ｓｉ酸窒化物という）層を形成すると、
上記超硬基体の表面には、回転テーブル上の中心軸から半径方向に離れた位置に偏心して配置された前記超硬基体が上記の一方側の相対的にＡｌ含有量の高いＡｌ−Ｔｉ−Ｓｉ合金のカソード電極（蒸発源）に最も接近した時点で層中にＡｌおよび酸素の最高含有点が形成され、また前記前記超硬基体が上記の他方側の相対的にＴｉ含有量の高いＴｉ−Ａｌ−Ｓｉ合金のカソード電極に最も接近した時点で層中にＴｉおよび窒素の最高含有点が形成されることから、上記回転テーブルの回転によって層中には厚さ方向にそって前記Ａｌおよび酸素の最高含有点とＴｉおよび窒素の最高含有点が所定間隔をもって交互に繰り返し現れると共に、前記Ａｌおよび酸素の最高含有点から前記Ｔｉおよび窒素の最高含有点、前記Ｔｉおよび窒素の最高含有点から前記Ａｌおよび酸素の最高含有点へＡｌと酸素およびＴｉと窒素の含有割合がそれぞれ連続的に変化する成分濃度分布構造をもったＡｌ−Ｔｉ−Ｓｉ酸窒化物層からなる硬質被覆層が形成されるようになること。
【０００８】
（ｂ）上記（ａ）の繰り返し連続変化成分濃度分布構造のＡｌ−Ｔｉ−Ｓｉ酸窒化物層の形成に際して、例えば対向配置のカソード電極（蒸発源）のそれぞれの組成、並びに装置内で連続変化する反応雰囲気の組成、すなわち酸素と窒素の相互導入割合を調製すると共に、超硬基体が装着されている回転テーブルの回転速度を制御して、
上記Ａｌおよび酸素の最高含有点が、
組成式：（Ａｌ_1-(X+Z)Ｔｉ_XＳｉ_Z）Ｏ_1-DＮ_D（ただし、原子比で、Ｘは０．１０〜０．２５、Ｚは０．０１〜０．１０、Ｄは０．０２〜０．１０）、
上記Ｔｉおよび窒素の最高含有点が、
組成式：（Ｔｉ_1-(Y+Z)Ａｌ_YＳｉ_Z）Ｎ_1-EＯ_E（ただし、原子比で、Ｙは０．３５〜０．６０、Ｚは０．０１〜０．１０、Ｅは０．０２〜０．１０）、
を満足し、かつ隣り合う上記Ａｌおよび酸素の最高含有点と上記Ｔｉおよび窒素の最高含有点の間隔を、０．０１〜０．１μmとすると、
上記Ａｌおよび酸素の最高含有点部分では、Ａｌと酸素の作用で、Ｓｉ成分による一段の耐熱性向上と相俟って、すぐれた高温硬さと耐熱性を示し、一方上記Ｔｉおよび窒素の最高含有点部分では、Ｔｉと窒素の高含有によってすぐれた高温強度が確保され、かつこれらＡｌおよび酸素の最高含有点と上記Ｔｉおよび窒素の最高含有点の間隔をきわめて小さくしたことから、層全体の特性としてすぐれた高温硬さと耐熱性、およびすぐれた高温強度を具備するようになり、さらに前記両点間でＡｌと酸素およびＴｉと窒素の含有割合がそれぞれ連続的に変化（成分濃度分布構造）することにより、硬質被覆層内には層界面が存在しないことになり、したがって、硬質被覆層がかかる構成のＡｌ−Ｔｉ−Ｓｉ酸窒化物層を硬質被覆層として形成してなる被覆超硬工具は、特に粘性の高い各種のステンレス鋼や軟鋼などの難削材の高い発熱を伴なう高速切削で、切刃稜線部に偏摩耗の原因となる熱塑性変形の発生なく、硬質被覆層がすぐれた耐摩耗性を発揮するようになること。
以上（ａ）および（ｂ）に示される研究結果を得たのである。
【０００９】
この発明は、上記の研究結果に基づいてなされたものであって、
（１）超硬基体の表面に、Ａｌ−Ｔｉ−Ｓｉ酸窒化物層からなる硬質被覆層を１〜１５μｍの全体平均層厚で物理蒸着してなる被覆超硬工具にして、前記硬質被覆層が、層厚方向にそって、Ａｌおよび酸素の最高含有点とＴｉおよび窒素の最高含有点とが所定間隔をおいて交互に繰り返し存在し、かつ前記Ａｌおよび酸素の最高含有点から前記Ｔｉおよび窒素の最高含有点、前記Ｔｉおよび窒素の最高含有点から前記Ａｌおよび酸素の最高含有点へＡｌと酸素およびＴｉと窒素の含有割合がそれぞれ連続的に変化する成分濃度分布構造を有し、
さらに、上記Ａｌおよび酸素の最高含有点が、
組成式：（Ａｌ_1-(X+Z)Ｔｉ_XＳｉ_Z）Ｏ_1-DＮ_D（ただし、原子比で、Ｘは０．１０〜０．２５、Ｚは０．０１〜０．１０、Ｄは０．０２〜０．１０）、
上記Ｔｉおよび窒素の最高含有点が、
組成式：（Ｔｉ_1-(Y+Z)Ａｌ_YＳｉ_Z）Ｎ_1-EＯ_E（ただし、原子比で、Ｙは０．３５〜０．６０、Ｚは０．０１〜０．１０、Ｅは０．０２〜０．１０）、
を満足し、かつ隣り合う上記Ａｌおよび酸素の最高含有点と上記Ｔｉおよび窒素の最高含有点の間隔が、０．０１〜０．１μmである、
高速切削条件で硬質被覆層がすぐれた耐摩耗性を発揮する被覆超硬工具。
（２）（ａ）アークイオンプレーティング装置内の回転テーブル上に、前記回転テーブルの中心軸から半径方向に離れた位置に偏心して超硬基体を自転自在に装着し、
（ｂ）また、上記回転テーブルを挟んで、いずれもカソード電極（蒸発源）として、相対的にＡｌ含有割合の高いＡｌ−Ｔｉ−Ｓｉ合金と、相対的にＴｉ含有割合の高いＴｉ−Ａｌ−Ｓｉ合金を対向配置すると共に、それぞれ前記Ａｌ−Ｔｉ−Ｓｉ合金に比してＡｌ含有割合が低く、かつ前記Ｔｉ−Ａｌ−Ｓｉ合金に比してＴｉ含有割合が低い中間Ａｌ／Ｔｉ／Ｓｉ合金と中間Ｔｉ／Ａｌ／Ｓｉ合金を同じく対向配置し、
（ｃ）上記回転テーブルを挟んで対向配置した上記のカソード電極と、前記カソード電極のそれぞれに並設されたアノード電極との間にアーク放電を発生させ、
（ｄ）上記アークイオンプレーティング装置内の反応雰囲気を酸素と窒素の混合雰囲気とするが、前記装置内への酸素と窒素の相対導入割合を上記超硬基体の回転移動位置に対応して調整して、前記超硬基体が上記の相対的にＡｌ含有割合の高いＡｌ−Ｔｉ−Ｓｉ合金のカソード電極に最も接近した時点での反応雰囲気を酸素導入割合が最も高く、窒素導入割合が最も低い反応雰囲気とする一方、前記超硬基体が上記の相対的にＴｉ含有割合の高いＴｉ−Ａｌ−Ｓｉ合金のカソード電極に最も接近した時点での反応雰囲気を窒素導入割合が最も高く、酸素導入割合が最も低い反応雰囲気とすると共に、前記超硬基体が前記Ａｌ−Ｔｉ−Ｓｉ合金のカソード電極最接近位置から上記中間Ａｌ／Ｔｉ／Ｓｉ合金のカソード電極最接近位置を経て前記Ｔｉ−Ａｌ−Ｓｉ合金のカソード電極最接近位置に回転移動する間の反応雰囲気を、酸素導入割合が連続的に減少し、これに対応して窒素導入割合が連続的に増加する連続変化雰囲気とし、一方前記超硬基体が前記Ｔｉ−Ａｌ−Ｓｉ合金のカソード電極最接近位置から上記中間Ｔｉ／Ａｌ／Ｓｉ合金のカソード電極最接近位置を経て前記Ａｌ−Ｔｉ−Ｓｉ合金のカソード電極最接近位置に回転移動する間の反応雰囲気を、窒素導入割合が連続的に減少し、これに対応して酸素導入割合が連続的に増加する連続変化雰囲気とし、もって、上記回転テーブル上で自転しながら偏心回転する上記超硬基体の表面に、Ａｌ−Ｔｉ−Ｓｉ酸窒化物層からなる硬質被覆層を物理蒸着すること、
以上（ａ）〜（ｅ）の工程により高速切削条件で硬質被覆層がすぐれた耐摩耗性を発揮する被覆超硬工具を製造する方法。
以上（１）および（２）に特徴を有するものである。
【００１０】
つぎに、この発明の被覆超硬工具において、硬質被覆層であるＡｌ−Ｔｉ−Ｓｉ酸窒化物層の構成を上記の通りに限定した理由を説明する。
（ａ）Ａｌおよび酸素の最高含有点
上記Ａｌ−Ｔｉ−Ｓｉ酸窒化物層において、Ａｌおよび酸素の最高含有点部分では高含有のＡｌと酸素の作用ですぐれた高温硬さと耐熱性を示し、さらにＳｉ成分の作用で一段の耐熱性の向上が図られ、一方Ｔｉおよび窒素の最高含有点部分では相対的に高い含有割合のＴｉ成分と窒素の作用で強度が向上し、かつ前記Ｔｉ成分の含有割合に相当した高含有のＡｌ成分とＳｉ成分の作用と相俟って、高温ですぐれた高強度を具備するようになり、したがってＡｌおよび酸素の最高含有点では、ＴｉのＡｌおよびＳｉとの合量に占める含有割合を示すＸ値が、原子比で０．１０未満になったり、窒素の酸素との合量に占める含有割合を示すＤ値が、同じく原子比で（以下、同じ）０．０２未満になったりすると、Ａｌや酸素の割合が多くなり過ぎて、すぐれた高温強度を有するＴｉと窒素の最高含有点が隣接して存在しても層自体の強度はきわめて低いものとなり、この結果チッピングなどが発生し易くなり、一方同Ｘ値が０．２５を越えたり、同Ｄ値が０．１０を越えたりすると、高温硬さおよび耐熱性が急激に低下し、摩耗促進の原因となり、またＳｉ成分のＡｌとＴｉの合量に占める割合を示すＺ値が０．０１未満せは所望の耐熱性向上効果が得られず、同Ｚ値が０．１０を越えると強度が急激に低下するようになることから、Ｔｉの含有割合を示すＸ値を０．１０〜０．２５、Ｓｉの含有割合を示すＺ値を０．０１〜０．１０、および窒素の含有割合を示すＤ値を０．０２〜０．１０と定めた。
【００１１】
（ｂ）Ｔｉおよび窒素の最高含有点
上記の通りＡｌおよび酸素の最高含有点は相対的にすぐれた高温硬さおよび耐熱性を有するが、反面相対的に高温強度の低いものであるため、このＡｌおよび酸素の最高含有点の高温強度不足を補う目的で、相対的にすぐれた高温強度を有するＴｉおよび窒素の最高含有点を厚さ方向に交互に介在させるものである。しかし、ＡｌのＴｉとＳｉの合量に占める含有割合を示すＹ値が０．３５未満では、所望の高温硬さおよび耐熱性を確保することができず、この結果切刃稜線部に熱塑性変形が発生し、これが原因で硬質被覆層の摩耗進行が一段と促進されようになり、また同Ｙ値が０．６０を越えると、高温強度が急激に低下し、硬質被覆層にチッピングが発生し易くなり、一方酸素の窒素との合量に占める含有割合を示すＥ値が０．０２未満になると、Ｔｉおよび窒素の最高含有点の高温硬さおよび耐熱性が急激に低下し、これが摩耗促進の原因となり、また同Ｅ値が０．１０を越えると、高温強度が急激に低下し、これがチッピング発生の原因となることから、Ａｌの含有割合を示すＹ値を０．３５〜０．６０、酸素の含有割合を示すＥ値を０．０２〜０．１０と定めた。
また、Ｓｉ成分は上記のＡｌおよび酸素の最高含有点におけると同じ耐熱性向上効果を図るという目的で含有するものであり、したがって、その含有割合を示すＺ値も同じ理由で０．０１〜０．１０と定めた。
【００１２】
（ｃ）Ａｌおよび酸素の最高含有点とＴｉおよび窒素の最高含有点間の間隔
その間隔が０．０１μm未満ではそれぞれの点を上記の組成で明確に形成することが困難であり、この結果層に所望のすぐれた高温硬さおよび耐熱性、さらに高温強度を確保することができなくなり、またその間隔が０．１μmを越えるとそれぞれの点がもつ欠点、すなわちＡｌおよび酸素の最高含有点であれば高温強度不足、Ｔｉおよび窒素の最高含有点であれば高温硬さおよび耐熱性不足が層内に局部的に現れ、これが原因で熱塑性変形が発生し易くなったり、摩耗進行が一段と促進されるようになることから、その間隔を０．０１〜０．１μmと定めた。
【００１３】
（ｄ）硬質被覆層の全体平均層厚
その層厚が１μｍ未満では、所望の耐摩耗性を確保することができず、一方その平均層厚が１５μｍを越えると、切刃にチッピングが発生し易くなることから、その平均層厚を１〜１５μｍと定めた。
【００１４】
【発明の実施の形態】
つぎに、この発明の被覆超硬工具およびその製造方法を実施例により具体的に説明する。
（実施例１）
原料粉末として、いずれも１〜３μｍの平均粒径を有するＷＣ粉末、ＴｉＣ粉末、ＶＣ粉末、ＴａＣ粉末、ＮｂＣ粉末、Ｃｒ₃Ｃ₂粉末、およびＣｏ粉末を用意し、これら原料粉末を、表１に示される配合組成に配合し、ボールミルで６０時間湿式混合し、乾燥した後、１００ＭＰａの圧力で圧粉体にプレス成形し、この圧粉体を６Ｐａの真空中、温度：１４２０℃に１時間保持の条件で焼結し、焼結後、切刃部分にＲ：０．０３のホーニング加工を施すことにより、ＩＳＯ規格・ＣＮＭＧ１２０４１２のチップ形状をもったＷＣ基超硬合金製の超硬基体Ａ−１〜Ａ−１０を形成した。
【００１５】
また、原料粉末として、いずれも０．５〜２μｍの平均粒径を有するＴｉＣＮ（質量比でＴｉＣ／ＴｉＮ＝５０／５０）粉末、Ｍｏ₂Ｃ粉末、ＺｒＣ粉末、ＮｂＣ粉末、ＴａＣ粉末、ＷＣ粉末、Ｃｏ粉末、およびＮｉ粉末を用意し、これら原料粉末を、表２に示される配合組成に配合し、ボールミルで６０時間湿式混合し、乾燥した後、１００ＭＰａの圧力で圧粉体にプレス成形し、この圧粉体を２ｋＰａの窒素雰囲気中、温度：１５２０℃に１時間保持の条件で焼結し、焼結後、切刃部分にＲ：０．０３のホーニング加工を施すことにより、ＩＳＯ規格・ＣＮＭＧ１２０４１２のチップ形状をもったＴｉＣＮ系サーメット製の超硬基体Ｂ−１〜Ｂ−６を形成した。
【００１６】
ついで、上記の超硬基体Ａ−１〜Ａ−１０およびＢ−１〜Ｂ−６のそれぞれを、アセトン中で超音波洗浄し、乾燥した状態で、図１に示されるアークイオンプレーティング装置内の回転テーブル上に、前記回転テーブルの中心軸から半径方向に離れた位置に偏心して自転自在に装着し、いずれもカソード電極（蒸発源）として、種々の成分組成をもったＡｌおよび酸素最高含有点形成用Ａｌ−Ｔｉ−Ｓｉ合金と、同じく種々の成分組成をもったＴｉおよび窒素最高含有点形成用Ｔｉ−Ａｌ−Ｓｉ合金を前記回転テーブルを挟んで対向配置し、さらにそれぞれ前記Ａｌ−Ｔｉ−Ｓｉ合金に比してＡｌ含有割合が低く、かつ前記Ｔｉ−Ａｌ−Ｓｉ合金に比してＴｉ含有割合が低い中間Ａｌ／Ｔｉ／Ｓｉ合金と中間Ｔｉ／Ａｌ／Ｓｉ合金を同じく対向配置し、またボンバート洗浄用金属Ｔｉも装着し、まず装置内を排気して０．５Ｐａ以下の真空に保持しながら、ヒーターで装置内を５００℃に加熱した後、前記回転テーブル上で自転しながら回転する超硬基体に−１０００Ｖの直流バイアス電圧を印加し、かつカソード電極の前記金属Ｔｉとアノード電極との間に１００Ａの電流を流してアーク放電を発生させ、もって超硬基体表面をＴｉボンバート洗浄し、ついで、前記回転テーブル上で自転しながら回転する超硬基体に−３０Ｖの直流バイアス電圧を印加し、かつそれぞれのカソード電極(前記Ａｌおよび酸素最高含有点形成用Ａｌ−Ｔｉ−Ｓｉ合金、前記Ｔｉおよび窒素最高含有点形成用Ｔｉ−Ａｌ−Ｓｉ合金、さらに前記中間Ａｌ／Ｔｉ／Ｓｉ合金および中間Ｔｉ／Ａｌ／Ｓｉ合金)とアノード電極との間に１５０Ａの電流を流してアーク放電を発生させ、かつ装置内の反応雰囲気の圧力を３Ｐａに保持しながら、前記超硬基体が上記の相対的にＡｌ含有割合の高いＡｌ−Ｔｉ−Ｓｉ合金のカソード電極（蒸発源）に最も接近した時点での反応雰囲気を酸素導入割合が最も高く、窒素導入割合が最も低い反応雰囲気とする一方、前記超硬基体が上記の相対的にＴｉ含有割合の高いＴｉ−Ａｌ−Ｓｉ合金のカソード電極に最も接近した時点での反応雰囲気を窒素導入割合が最も高く、酸素導入割合が最も低い反応雰囲気とすると共に、前記超硬基体が前記Ａｌ−Ｔｉ−Ｓｉ合金のカソード電極最接近位置から上記中間Ａｌ／Ｔｉ／Ｓｉ合金のカソード電極最接近位置を経て前記Ｔｉ−Ａｌ−Ｓｉ合金のカソード電極最接近位置に回転移動する間の反応雰囲気を、酸素導入割合が連続的に減少し、これに対応して窒素導入割合が連続的に増加する連続変化雰囲気とし、一方前記超硬基体が前記Ｔｉ−Ａｌ−Ｓｉ合金のカソード電極最接近位置から上記中間Ｔｉ／Ａｌ／Ｓｉ合金のカソード電極最接近位置を経て前記Ａｌ−Ｔｉ−Ｓｉ合金のカソード電極最接近位置に回転移動する間の反応雰囲気を、窒素導入割合が連続的に減少し、これに対応して酸素導入割合が連続的に増加する連続変化雰囲気とした条件で本発明法を実施し、もって前記超硬基体の表面に、厚さ方向に沿って表３，４に示される目標組成のＡｌおよび酸素最高含有点とＴｉおよび窒素最高含有点とが交互に、同じく表３，４に示される目標間隔で繰り返し存在し、かつ前記Ａｌおよび酸素最高含有点から前記Ｔｉおよび窒素最高含有点、前記Ｔｉおよび窒素最高含有点から前記Ａｌおよび酸素最高含有点へＡｌと酸素およびＴｉと窒素の含有割合がそれぞれ連続的に変化する成分濃度分布構造を有し、かつ同じく表３，４に示される目標全体層厚の硬質被覆層を蒸着形成してなる本発明被覆超硬工具としての本発明表面被覆超硬合金製スローアウエイチップ（以下、本発明被覆超硬チップと云う）１〜１６をそれぞれ製造した。
【００１７】
また、比較の目的で、これら超硬基体Ａ−１〜Ａ−１０およびＢ−１〜Ｂ−６を、アセトン中で超音波洗浄し、乾燥した状態で、それぞれ図２に示される通常のアークイオンプレーティング装置に装入し、カソード電極（蒸発源）として種々の成分組成をもったＴｉ−Ａｌ−Ｓｉ合金を装着し、さらにボンバード洗浄用金属Ｔｉも装着し、まず、装置内を排気して０．５Ｐａ以下の真空に保持しながら、ヒーターで装置内を５００℃に加熱した後、前記超硬基体に−１０００Ｖの直流バイアス電圧を印加し、かつカソード電極の前記金属Ｔｉとアノード電極との間に１００Ａの電流を流してアーク放電を発生させて超硬基体表面をＴｉボンバード洗浄し、ついで装置内に反応ガスとして窒素ガスを導入して２Ｐａの反応雰囲気とすると共に、超硬基体に−１００Ｖの直流バイアス電圧を印加し、前記カソード電極のＴｉ−Ａｌ−Ｓｉ合金とアノード電極との間に１００Ａの電流を流してアーク放電を発生させる条件で従来法を実施し、もって前記超硬基体Ａ−１〜Ａ−１０およびＢ−１〜Ｂ−６のそれぞれの表面に、表５，６に示される目標組成および目標層厚を有し、かつ層厚方向に沿って実質的に組成変化のない（Ｔｉ，Ａｌ，Ｓｉ）Ｎ層からなる硬質被覆層を蒸着形成してなる従来被覆超硬工具としての従来表面被覆超硬合金製スローアウエイチップ（以下、従来被覆超硬チップと云う）１〜１６をそれぞれ製造した。
【００１８】
つぎに、上記本発明法および従来法により得られた上記本発明被覆超硬チップ１〜１６および従来被覆超硬チップ１〜１６を工具鋼製バイトの先端部に固定治具にてネジ止めした状態で、
被削材：ＪＩＳ・ＳＵＳ３１６の丸棒、
切削速度：２５０ｍ／ｍｉｎ．、
切り込み：１．５ｍｍ、
送り：０．２０ｍｍ／ｒｅｖ．、
切削時間：１０分、
の条件でのステンレス鋼の乾式連続高速切削加工試験、
被削材：ＪＩＳ・ＳＵＳ３０４の長さ方向等間隔４本縦溝入り丸棒、
切削速度：２２０ｍ／ｍｉｎ．、
切り込み：１．５ｍｍ、
送り：０．２０ｍｍ／ｒｅｖ．、
切削時間：５分、
の条件でのステンレス鋼の乾式断続高速切削加工試験、さらに、
被削材：ＪＩＳ・Ｓ１５Ｃの長さ方向等間隔４本縦溝入り丸棒、
切削速度：３２０ｍ／ｍｉｎ．、
切り込み：２．０ｍｍ、
送り：０．２５ｍｍ／ｒｅｖ．、
切削時間：５分、
の条件での軟鋼の乾式断続高速切削加工試験を行い、いずれの切削加工試験でも切刃の逃げ面摩耗幅を測定した。この測定結果を表５〜６に示した。
【００１９】
【表１】

【００２０】
【表２】

【００２１】
【表３】

【００２２】
【表４】

【００２３】
【表５】

【００２４】
【表６】

【００２５】
（実施例２）
原料粉末として、平均粒径：５．５μｍを有する中粗粒ＷＣ粉末、同０．８μｍの微粒ＷＣ粉末、同１．３μｍのＴａＣ粉末、同１．２μｍのＮｂＣ粉末、同１．２μｍのＺｒＣ粉末、同２．３μｍのＣｒ₃Ｃ₂粉末、同１．５μｍのＶＣ粉末、同１．０μｍの（Ｔｉ，Ｗ）Ｃ［質量比で、ＴｉＣ／ＷＣ＝５０／５０］粉末、および同１．８μｍのＣｏ粉末を用意し、これら原料粉末をそれぞれ表７に示される配合組成に配合し、さらにワックスを加えてアセトン中で６０時間ボールミル混合し、減圧乾燥した後、１００ＭＰａの圧力で所定形状の各種の圧粉体にプレス成形し、これらの圧粉体を、６Ｐａの真空雰囲気中、７℃／分の昇温速度で１３７０〜１４７０℃の範囲内の所定の温度に昇温し、この温度に１時間保持後、炉冷の条件で焼結して、直径が８ｍｍ、１３ｍｍ、および２６ｍｍの３種の超硬基体形成用丸棒焼結体を形成し、さらに前記の３種の丸棒焼結体から、研削加工にて、表７に示される組合せで、切刃部の直径×長さがそれぞれ６ｍｍ×１３ｍｍ、１０ｍｍ×２２ｍｍ、および２０ｍｍ×４５ｍｍの寸法、並びにいずれもねじれ角：３０度の４枚刃スクエア形状をもった超硬基体（エンドミル）Ｃ−１〜Ｃ−８をそれぞれ製造した。
【００２６】
ついで、これらの超硬基体（エンドミル）Ｃ−１〜Ｃ−８の表面を、アセトン中で超音波洗浄し、乾燥した状態で、同じく図１に示されるアークイオンプレーティング装置に装入し、上記実施例１と同一の条件で本発明法を実施し、もって前記超硬基体（エンドミル）の表面に、厚さ方向に沿って表８に示される目標組成のＡｌおよび酸素最高含有点とＴｉおよび窒素最高含有点とが交互に、同じく表８に示される目標間隔で繰り返し存在し、かつ前記Ａｌおよび酸素最高含有点から前記Ｔｉおよび窒素最高含有点、前記Ｔｉおよび窒素最高含有点から前記Ａｌおよび酸素最高含有点へＡｌと酸素およびＴｉと窒素の含有割合がそれぞれ連続的に変化する成分濃度分布構造を有し、かつ同じく表８に示される目標全体層厚の硬質被覆層を蒸着形成してなる本発明被覆超硬工具としての本発明被覆超硬エンドミル１〜８を製造した。
【００２７】
また、比較の目的で、上記の超硬基体（エンドミル）Ｃ−１〜Ｃ−８を、アセトン中で超音波洗浄し、乾燥した状態で、同じく図２に示される通常のアークイオンプレーティング装置に装入し、上記実施例１と同一の条件で従来法を実施し、もって、表９に示される目標組成および目標層厚を有し、かつ層厚方向に沿って実質的に組成変化のない（Ｔｉ，Ａｌ，Ｓｉ）Ｎ層からなる硬質被覆層を蒸着形成してなる従来被覆超硬工具としての従来表面被覆超硬合金製エンドミル（以下、従来被覆超硬エンドミルと云う）１〜８をそれぞれ製造した。
【００２８】
つぎに、上記本発明法および従来法により得られた上記本発明被覆超硬エンドミル１〜８および従来被覆超硬エンドミル１〜８のうち、本発明被覆超硬エンドミル１〜３および従来被覆超硬エンドミル１〜３については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＳＵＳ３０４の板材、
切削速度：８０ｍ／ｍｉｎ．、
軸方向切り込み：６ｍｍ、
径方向切り込み：０．６ｍｍ、
テーブル送り：３２０ｍｍ／分、
の条件でのステンレス鋼の湿式高速側面切削加工試験、上記の本発明法および従来法により得られた本発明被覆超硬エンドミル４〜６および従来被覆超硬エンドミル４〜６については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・Ｓ１５Ｃの板材、
切削速度：１６０ｍ／ｍｉｎ．、
軸方向切り込み：８ｍｍ、
径方向切り込み：１ｍｍ、
テーブル送り：６００ｍｍ／分、
の条件での軟鋼の湿式高速側面切削加工試験、本発明法および従来法により得られた本発明被覆超硬エンドミル７，８および従来被覆超硬エンドミル７，８については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＳＵＳ３１６の板材、
切削速度：７５ｍ／ｍｉｎ．、
軸方向切り込み：１５ｍｍ、
径方向切り込み：２ｍｍ、
テーブル送り：３００ｍｍ／分、
の条件でのステンレス鋼の湿式高速側面切削加工試験をそれぞれ行い、いずれの湿式側面切削加工試験（水溶性切削油使用）でも切刃部の外周刃の逃げ面摩耗幅が使用寿命の目安とされる０．１ｍｍに至るまでの切削長を測定した。この測定結果を表８、９にそれぞれ示した。
【００２９】
【表７】

【００３０】
【表８】

【００３１】
【表９】

【００３２】
（実施例３）
上記の実施例２で製造した直径が８ｍｍ（超硬基体Ｃ−１〜Ｃ−３形成用）、１３ｍｍ（超硬基体Ｃ−４〜Ｃ−６形成用）、および２６ｍｍ（超硬基体Ｃ−７、Ｃ−８形成用）の３種の丸棒焼結体を用い、この３種の丸棒焼結体から、研削加工にて、溝形成部の直径×長さがそれぞれ４ｍｍ×１３ｍｍ（超硬基体Ｄ−１〜Ｄ−３）、８ｍｍ×２２ｍｍ（超硬基体Ｄ−４〜Ｄ−６）、および１６ｍｍ×４５ｍｍ（超硬基体Ｄ−７、Ｄ−８）の寸法、並びにいずれもねじれ角：３０度の２枚刃形状をもった超硬基体（ドリル）Ｄ−１〜Ｄ−８をそれぞれ製造した。
【００３３】
ついで、これらの超硬基体（ドリル）Ｄ−１〜Ｄ−８の切刃に、ホーニングを施し、アセトン中で超音波洗浄し、乾燥した状態で、同じく図１に示されるアークイオンプレーティング装置に装入し、上記実施例１と同一の条件で本発明法を実施し、もって前記超硬基体（ドリル）の表面に、厚さ方向に沿って表１０に示される目標組成のＡｌおよび酸素最高含有点とＴｉおよび窒素最高含有点とが交互に同じく表１０に示される目標間隔で繰り返し存在し、かつ前記Ａｌおよび酸素最高含有点から前記Ｔｉおよび窒素最高含有点、前記Ｔｉおよび窒素最高含有点から前記Ａｌおよび酸素最高含有点へＡｌと酸素およびＴｉと窒素の含有割合がそれぞれ連続的に変化する成分濃度分布構造を有し、かつ同じく表１０に示される目標全体層厚の硬質被覆層を蒸着形成してなる本発明被覆超硬工具としての本発明被覆超硬ドリル１〜８それぞれを製造した。
【００３４】
また、比較の目的で、上記の超硬基体（ドリル）Ｄ−１〜Ｄ−８の切刃に、ホーニングを施し、アセトン中で超音波洗浄し、乾燥した状態で、同じく図２に示される通常のアークイオンプレーティング装置に装入し、上記実施例１と同一の条件で従来法を実施し、もって、表１１に示される目標組成および目標層厚を有し、かつ層厚方向に沿って実質的に組成変化のない（Ｔｉ，Ａｌ，Ｓｉ）Ｎ層からなる硬質被覆層を蒸着形成してなる従来被覆超硬工具としての従来表面被覆超硬合金製ドリル（以下、従来被覆超硬ドリルと云う）１〜８をそれぞれ製造した。
【００３５】
つぎに、上記本発明法および従来法により得られた上記本発明被覆超硬ドリル１〜８および従来被覆超硬ドリル１〜８のうち、本発明被覆超硬ドリル１〜３および従来被覆超硬ドリル１〜３については、
被削材：平面寸法：１００ｍｍ×２５０、厚さ：５０ｍｍのＪＩＳ・Ｓ１５Ｃの板材、
切削速度：１４０ｍ／ｍｉｎ．、
送り：０．１４ｍｍ／ｒｅｖ、
穴深さ：８ｍｍ、
の条件での軟鋼の湿式高速穴あけ切削加工試験、上記の本発明法および従来法により得られた本発明被覆超硬ドリル４〜６および従来被覆超硬ドリル４〜６については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＳＵＳ３０４の板材、
切削速度：１００ｍ／ｍｉｎ．、
送り：０．１８ｍｍ／ｒｅｖ、
穴深さ：１６ｍｍ、
の条件でのステンレス鋼の湿式高速穴あけ切削加工試験、本発明法および従来法により得られた本発明被覆超硬ドリル７，８および従来被覆超硬ドリル７，８については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・Ｓ１５Ｃの板材、
切削速度：１００ｍ／ｍｉｎ．、
送り：０．２７ｍｍ／ｒｅｖ、
穴深さ：２４ｍｍ、
の条件での軟鋼の湿式高速穴あけ切削加工試験、をそれぞれ行い、いずれの湿式高速高送り穴あけ切削加工試験（水溶性切削油使用）でも先端切刃面の逃げ面摩耗幅が０．３ｍｍに至るまでの穴あけ加工数を測定した。この測定結果を表１０、１１にそれぞれ示した。
【００３６】
【表１０】

【００３７】
【表１１】

【００３８】
上記の本発明法で得られた本発明被覆超硬工具としての本発明被覆超硬チップ１〜１６、本発明被覆超硬エンドミル１〜８、および本発明被覆超硬ドリル１〜８、並びに従来法で得られた従来被覆超硬工具としての従来被覆超硬チップ１〜１６、従来被覆超硬エンドミル１〜８、および従来被覆超硬ドリル１〜８を構成する硬質被覆層について、厚さ方向に沿ってＡｌ、Ｔｉ、Ｓｉ、酸素、および窒素の含有割合ををオージェ分光分析装置を用いて測定したところ、前記本発明被覆超硬工具の硬質被覆層では、Ａｌおよび酸素の最高含有点とＴｉおよび窒素の最高含有点とがそれぞれ目標値と実質的に同じ組成および間隔で交互に繰り返し存在し、かつ前記Ａｌおよび酸素の最高含有点から前記Ｔｉおよび窒素の最高含有点、前記Ｔｉおよび窒素の最高含有点から前記Ａｌおよび酸素の最高含有点へＡｌとＴｉおよび酸素と窒素の含有割合がそれぞれ連続的に変化する成分濃度分布構造を有することが確認され、さらに硬質被覆層の平均層厚も目標全体層厚と実質的に同じ値を示した。一方、前記従来被覆超硬工具の硬質被覆層では、目標組成と実質的に同じ組成および目標全体層厚と実質的に同じ全体平均層厚を示すものの、厚さ方向に沿った組成変化は見られず、層全体に亘って均質な組成を示すものであった。
【００３９】
【発明の効果】
表３〜１１に示される結果から、上記本発明法で得られた、硬質被覆層が層厚方向に、相対的にすぐれた高温硬さと耐熱性を有するＡｌおよび酸素の最高含有点と相対的にすぐれた高温強度を有するＴｉおよび窒素の最高含有点とが交互に所定間隔をおいて繰り返し存在し、かつ前記Ａｌおよび酸素の最高含有点から前記Ｔｉおよび窒素の最高含有点、前記Ｔｉおよび窒素の最高含有点から前記Ａｌおよび酸素の最高含有点へＡｌとＴｉおよび酸素と窒素の含有割合がそれぞれ連続的に変化する成分濃度分布構造を有するＡｌ−Ｔｉ−Ｓｉ酸窒化物層からなる被覆超硬工具は、いずれも粘性の高い各種のステンレス鋼や軟鋼などの難削材の切削加工を、特に高い発熱を伴う高速条件で行なった場合にも、硬質被覆層に熱塑性変形の発生なく、正常摩耗を示し、すぐれた耐摩耗性を示すのに対して、上記従来法で得られた、硬質被覆層が層厚方向に沿って実質的に組成変化のない（Ｔｉ，Ａｌ，Ｓｉ）Ｎ層からなる従来被覆超硬工具においては、前記の高速重切削条件では、前記硬質被覆層の高温硬さおよび耐熱性不足が原因で、切刃部のすくい面と逃げ面の交わる切刃稜線部に熱塑性変形が発生し、この結果前記硬質被覆層の摩耗進行が一段と促進されるようになることから、比較的短時間で使用寿命に至ることが明らかである。
上述のように、この発明の方法によれば、通常の条件での切削加工は勿論のこと、特に各種のステンレス鋼や軟鋼などの難削材の切削加工を、特に高い発熱を伴う高速条件で行なった場合にも、長期に亘ってすぐれた耐摩耗性を示す被覆超硬工具を製造することができ、したがって、この結果の被覆超硬工具は切削加工の省力化および省エネ化、さらに低コスト化に十分満足に対応することができるものである。
【図面の簡単な説明】
【図１】この発明の被覆超硬工具を構成する硬質被覆層を形成するのに用いたアークイオンプレーティング装置を示し、（ａ）は概略平面図、（ｂ）は概略正面図である。
【図２】従来被覆超硬工具を構成する硬質被覆層を形成するのに用いた通常のアークイオンプレーティング装置の概略説明図である。[0001]
BACKGROUND OF THE INVENTION
In the present invention, the hard coating layer has excellent high-temperature strength and high-temperature hardness and heat resistance. Therefore, for example, cutting of difficult-to-cut materials such as various highly viscous stainless steels and mild steels has a particularly high heat generation. The present invention relates to a surface-coated cemented carbide cutting tool (hereinafter referred to as a coated cemented carbide tool) that exhibits excellent wear resistance when a hard coating layer is used, and a method for producing the same.
[0002]
[Prior art]
Generally, for coated carbide tools, a throw-away tip that is attached to the tip of a cutting tool for turning or flattening of various steel and cast iron work materials, and drilling of the work material. There are drills and miniature drills used for processing, etc., and solid type end mills used for chamfering, grooving, shoulder processing, etc. of the work material. A slow-away end mill tool that performs cutting work in the same manner as a type end mill is known.
[0003]
Further, as a coated carbide tool, a tungsten carbide (hereinafter referred to as WC) based cemented carbide substrate or a titanium carbonitride (hereinafter referred to as TiCN) based cermet substrate (hereinafter referred to as these carbide substrates). Are collectively referred to as “super-hard substrate”) on the surface of the composition formula: [Ti _{1- (Y + Z)} Al _Y Si _Z ) N] (wherein Y is 0.35 to 0.65 and Z is 0.01 to 0.10 in atomic ratio), and a composite nitride of Ti, Al, and Si [hereinafter, (Ti, A coated carbide tool formed by physically vapor-depositing a hard coating layer composed of a layer represented by Al, Si) N] with an average layer thickness of 1 to 15 μm is proposed, and the coated carbide tool constitutes the hard coating layer. (Ti, Al, Si) N steel has high temperature hardness and heat resistance due to Al component, and strength due to Ti component, and combined with a further increase in heat resistance due to Si component, various steels with high heat generation It is also known that it is used for continuous cutting and intermittent cutting processing of cast iron and cast iron (for example, see Patent Document 1).
[0004]
Furthermore, the above-mentioned coated carbide tool is, for example, the above-mentioned carbide substrate is inserted into an arc ion plating apparatus which is one type of physical vapor deposition apparatus schematically shown in FIG. For example, an arc discharge is generated between the anode electrode and a cathode electrode (evaporation source) on which a Ti—Al—Si alloy having a predetermined composition is set, for example, at a current of 90 A, while being heated to a temperature of 500 ° C. At the same time, nitrogen gas is introduced into the apparatus as a reaction gas to form a reaction atmosphere of, for example, 2 Pa. On the other hand, the carbide substrate is applied to the surface of the carbide substrate under a condition that a bias voltage of, for example, −100 V is applied. It is also well known that it is produced by vapor-depositing a hard coating layer composed of the (Ti, Al, Si) N layer. (For example, refer to Patent Document 1).
[0005]
[Patent Document 1]
Japanese Patent No. 2793773
[0006]
[Problems to be solved by the invention]
In recent years, the performance of cutting equipment has been dramatically improved, while on the other hand, there has been a strong demand for labor saving and energy saving and further cost reduction for cutting work, and this has led to a tendency to cut at higher speeds. However, in the above-mentioned conventional coated carbide tool, for example, when it is used for cutting difficult-to-cut materials such as various types of stainless steel and mild steel with high viscosity, particularly under high-speed conditions with high heat generation, Due to the high temperature hardness and insufficient heat resistance of the (Ti, Al, Si) N layer, which is a hard coating layer, thermoplastic deformation occurs at the cutting edge ridge line where the rake face and flank face of the cutting edge intersect. Since the progress of wear of the hard coating layer is further promoted, the service life is reached in a relatively short time.
[0007]
[Means for Solving the Problems]
In view of the above, the present inventors have focused particularly on the hard coating layer of the above-mentioned conventional coated carbide tool, and in high-speed cutting of difficult-to-cut materials such as various stainless steels and mild steels with particularly high viscosity. As a result of research to develop a hard coating layer that exhibits excellent wear resistance without the occurrence of thermoplastic deformation at the edge of the cutting edge,
(A) For example, an arc ion plating apparatus belonging to a physical vapor deposition apparatus having a structure shown in FIG. 1 (a) in a schematic plan view and in FIG. A table is provided, and an Al-Ti-Si alloy having a relatively high Al content ratio on one side and a Ti-Al-Si alloy having a relatively high Ti content ratio on the other side are arranged on both sides of the rotary table as a cathode. Oppositely arranged as electrodes (evaporation sources), both of which are low in Al content compared to the Al—Ti—Si alloy and low in Ti content compared to the Ti—Al—Si alloy. Using an arc ion plating apparatus in which a Ti / Si alloy and an intermediate Ti / Al / Si alloy are similarly arranged to face each other as a cathode electrode (evaporation source),
On the rotary table of this apparatus, the carbide substrate is mounted eccentrically at a position radially away from the central axis of the rotary table,
In this state, the reaction atmosphere in the apparatus is a mixed atmosphere of oxygen and nitrogen. The relative introduction ratio of oxygen and nitrogen into the apparatus is adjusted in accordance with the rotational movement position of the carbide substrate, and the super The reaction atmosphere at the time when the hard substrate is closest to the cathode electrode of the above Al-Ti-Si alloy having a relatively high Al content is the highest in the oxygen introduction rate and the lowest in the nitrogen introduction rate, preferably oxygen. While the relative introduction ratio is 90 to 97% by volume and the remainder is a reaction atmosphere made of nitrogen, the cemented carbide substrate is closest to the cathode electrode of the Ti-Al-Si alloy having a relatively high Ti content. The reaction atmosphere at the time is the highest nitrogen introduction ratio and the lowest oxygen introduction ratio, preferably a nitrogen relative introduction ratio of 90 to 97% by volume, and the remainder is oxygen. Reaction during rotational movement from the cathode electrode closest position of the Al-Ti-Si alloy through the cathode electrode closest position of the intermediate Al / Ti / Si alloy to the cathode electrode closest position of the Ti-Al-Si alloy The atmosphere is a continuously changing atmosphere in which the oxygen introduction rate is continuously decreased and the nitrogen introduction rate is continuously increased correspondingly, while the cemented carbide substrate is the cathode electrode of the Ti—Al—Si alloy. The reaction atmosphere during the rotational movement from the closest position to the closest cathode electrode position of the Al-Ti-Si alloy through the intermediate Ti / Al / Si alloy closest position of the cathode electrode is continuously increased. To a continuous change atmosphere that continuously increases the oxygen introduction rate correspondingly,
While rotating the rotary table and rotating the hard substrate itself for the purpose of uniforming the thickness of the hard coating layer formed by vapor deposition, between the cathode electrode (evaporation source) and the anode electrode, Under conditions that cause arc discharge in
When a composite oxynitride layer (hereinafter referred to as Al-Ti-Si oxynitride) of Al, Ti, and Si is formed,
On the surface of the cemented carbide substrate, the cemented carbide substrate arranged eccentrically at a position radially away from the central axis on the turntable has a relatively high Al content Al—Ti— on one side. At the point closest to the cathode electrode (evaporation source) of the Si alloy, the highest content point of Al and oxygen is formed in the layer, and the cemented carbide substrate is a Ti having a relatively high Ti content on the other side. When the closest point to the cathode electrode of the Al—Si alloy is formed, the highest content point of Ti and nitrogen is formed in the layer. Therefore, the rotation of the rotary table causes the Al and Si to move in the layer along the thickness direction. The highest content point of oxygen and the highest content point of Ti and nitrogen repeatedly appear at predetermined intervals, and from the highest content point of Al and oxygen, the highest content point of Ti and nitrogen, the highest content of Ti and nitrogen A hard coating layer comprising an Al-Ti-Si oxynitride layer having a component concentration distribution structure in which the content ratios of Al, oxygen, and Ti and nitrogen continuously change from the point to the highest content point of Al and oxygen. To be formed.
[0008]
(B) When the Al—Ti—Si oxynitride layer having the repeated continuous change component concentration distribution structure of (a) is formed, for example, the composition of each cathode electrode (evaporation source) arranged oppositely and the continuous change in the apparatus Adjusting the composition of the reaction atmosphere, that is, the mutual introduction ratio of oxygen and nitrogen, and controlling the rotation speed of the rotary table on which the carbide substrate is mounted,
The maximum content point of Al and oxygen is
Composition formula: (Al _{1- (X + Z)} Ti _X Si _Z ) O _1-D N _D (However, in atomic ratio, X is 0.10 to 0.25, Z is 0.01 to 0.10, D is 0.02 to 0.10),
The highest content point of Ti and nitrogen is
Composition formula: (Ti _{1- (Y + Z)} Al _Y Si _Z ) N _1-E O _E (However, in atomic ratio, Y is 0.35-0.60, Z is 0.01-0.10, E is 0.02-0.10),
And the distance between the highest content point of Al and oxygen adjacent to each other and the highest content point of Ti and nitrogen is 0.01 to 0.1 μm,
In the above-mentioned Al and oxygen maximum content point portion, combined with a further improvement in heat resistance by the Si component due to the action of Al and oxygen, shows excellent high temperature hardness and heat resistance, while the highest content of Ti and nitrogen In the point portion, excellent high-temperature strength is ensured by the high content of Ti and nitrogen, and the distance between the maximum content point of Al and oxygen and the maximum content point of Ti and nitrogen is extremely small. It has excellent high-temperature hardness and heat resistance, and excellent high-temperature strength, and the content ratio of Al and oxygen and Ti and nitrogen continuously changes between the two points (component concentration distribution structure). Therefore, there is no layer interface in the hard coating layer, and therefore, an Al-Ti-Si oxynitride layer having such a structure is formed as the hard coating layer. Cemented carbide tools made by high-speed cutting with high heat generation of difficult-to-cut materials such as various highly viscous stainless steels and mild steels, without the occurrence of thermoplastic deformation that causes uneven wear on the edge of the cutting edge The hard coating layer has excellent wear resistance.
The research results shown in (a) and (b) above were obtained.
[0009]
This invention was made based on the above research results,
(1) A hard coating layer formed by physically vapor-depositing a hard coating layer made of an Al-Ti-Si oxynitride layer on the surface of a cemented carbide substrate with an overall average layer thickness of 1 to 15 µm, However, along the layer thickness direction, the highest content point of Al and oxygen and the highest content point of Ti and nitrogen are alternately present at predetermined intervals, and from the highest content point of Al and oxygen, Ti and The highest concentration point of nitrogen, the content concentration distribution structure in which the content ratio of Al and oxygen and Ti and nitrogen continuously change from the highest content point of Ti and nitrogen to the highest content point of Al and oxygen, respectively,
Furthermore, the highest content point of Al and oxygen is
Composition formula: (Al _{1- (X + Z)} Ti _X Si _Z ) O _1-D N _D (However, in atomic ratio, X is 0.10 to 0.25, Z is 0.01 to 0.10, D is 0.02 to 0.10),
The highest content point of Ti and nitrogen is
Composition formula: (Ti _{1- (Y + Z)} Al _Y Si _Z ) N _1-E O _E (However, in atomic ratio, Y is 0.35-0.60, Z is 0.01-0.10, E is 0.02-0.10),
And the interval between the highest Al and oxygen content points adjacent to each other and the highest Ti and nitrogen content point is 0.01 to 0.1 μm.
Coated carbide tool that exhibits excellent wear resistance with a hard coating layer under high-speed cutting conditions.
(2) (a) On the rotary table in the arc ion plating apparatus, a carbide base is eccentrically mounted at a position away from the central axis of the rotary table in a radial direction, and the carbide substrate is rotatably mounted.
(B) Further, sandwiching the rotary table, both of them are used as cathode electrodes (evaporation sources), an Al—Ti—Si alloy having a relatively high Al content, and Ti—Al— having a relatively high Ti content. An intermediate Al / Ti / Si alloy in which Si alloys are arranged opposite to each other, and the Al content is lower than that of the Al-Ti-Si alloy, and the Ti content is lower than that of the Ti-Al-Si alloy. And the intermediate Ti / Al / Si alloy are also arranged opposite to each other,
(C) generating an arc discharge between the cathode electrode disposed opposite to the rotary table and the anode electrode arranged in parallel with each of the cathode electrodes;
(D) The reaction atmosphere in the arc ion plating apparatus is a mixed atmosphere of oxygen and nitrogen, and the relative introduction ratio of oxygen and nitrogen into the apparatus is adjusted according to the rotational movement position of the carbide substrate. The reaction atmosphere when the cemented carbide substrate is closest to the cathode electrode of the Al-Ti-Si alloy having a relatively high Al content is the highest in the oxygen introduction rate and the lowest in the nitrogen introduction rate. On the other hand, the reaction atmosphere at the time when the cemented carbide substrate is closest to the cathode electrode of the Ti-Al-Si alloy having a relatively high Ti content is the highest in the nitrogen introduction ratio and the oxygen introduction ratio. Is the lowest reaction atmosphere, and the cemented carbide substrate is moved from the closest proximity of the cathode electrode of the Al-Ti-Si alloy through the closest proximity of the cathode electrode of the intermediate Al / Ti / Si alloy. The reaction atmosphere during the rotational movement of the Ti—Al—Si alloy to the cathode electrode closest position is a continuously changing atmosphere in which the oxygen introduction rate continuously decreases and the nitrogen introduction rate continuously increases correspondingly. On the other hand, the carbide substrate approaches the cathode electrode closest to the cathode electrode of the Al-Ti-Si alloy from the cathode electrode closest proximity position of the Ti-Al-Si alloy through the cathode electrode closest proximity position of the intermediate Ti / Al / Si alloy. The reaction atmosphere during the rotational movement is a continuously changing atmosphere in which the nitrogen introduction rate continuously decreases and the oxygen introduction rate continuously increases correspondingly, so that the reaction atmosphere is eccentric while rotating on the rotary table. Physically vapor-depositing a hard coating layer made of an Al-Ti-Si oxynitride layer on the surface of the rotating carbide substrate,
A method for producing a coated carbide tool exhibiting excellent wear resistance with a hard coating layer under high-speed cutting conditions by the steps (a) to (e).
The above (1) and (2) are characteristic.
[0010]
Next, the reason why the structure of the Al—Ti—Si oxynitride layer, which is a hard coating layer, is limited as described above in the coated carbide tool of the present invention will be described.
(A) Maximum content point of Al and oxygen
In the Al-Ti-Si oxynitride layer, the highest content point of Al and oxygen shows excellent high temperature hardness and heat resistance by the action of the high content of Al and oxygen, and further the heat resistance by the action of the Si component. On the other hand, at the highest content point of Ti and nitrogen, strength is improved by the action of a relatively high content of Ti component and nitrogen, and a high content of Al component corresponding to the content of Ti component In combination with the action of Si and Si components, it has excellent strength at high temperatures. Therefore, at the highest content point of Al and oxygen, X indicates the content ratio of Ti to the total amount of Al and Si. When the value is less than 0.10 in atomic ratio, or the D value indicating the content ratio of the total amount of nitrogen with oxygen is also less than 0.02 in atomic ratio (hereinafter the same), Al And the proportion of oxygen increases Even if the highest content points of Ti and nitrogen having excellent high-temperature strength are adjacent to each other, the strength of the layer itself is extremely low, and as a result, chipping and the like are likely to occur, while the X value is 0.1. If it exceeds 25 or the D value exceeds 0.10, the high-temperature hardness and heat resistance will drastically decrease, causing wear promotion, and the ratio of the Si component to the total amount of Al and Ti will be shown. If the Z value is less than 0.01, the desired heat resistance improvement effect cannot be obtained, and if the Z value exceeds 0.10, the strength rapidly decreases, so the X value indicating the Ti content ratio 0.10 to 0.25, the Z value indicating the Si content ratio from 0.01 to 0.10, and the D value indicating the nitrogen content ratio from 0.02 to 0.10.
[0011]
(B) Maximum content point of Ti and nitrogen
As described above, the highest content point of Al and oxygen has relatively high high-temperature hardness and heat resistance, but on the other hand, it has a relatively low high-temperature strength. In order to compensate for the shortage, the highest content points of Ti and nitrogen having relatively high temperature strength are alternately interposed in the thickness direction. However, if the Y value indicating the proportion of Al in the total amount of Ti and Si is less than 0.35, the desired high-temperature hardness and heat resistance cannot be ensured, and as a result, the cutting edge ridge is deformed thermoplastically. As a result, the progress of wear of the hard coating layer is further promoted, and when the Y value exceeds 0.60, the high temperature strength decreases rapidly and the hard coating layer is likely to chip. On the other hand, when the E value indicating the content ratio of the total amount of oxygen with nitrogen is less than 0.02, the high temperature hardness and heat resistance of the highest content point of Ti and nitrogen are drastically reduced, which promotes wear. If the E value exceeds 0.10, the high-temperature strength decreases sharply, which causes chipping. Therefore, the Y value indicating the Al content ratio is set to 0.35 to 0.60, E value which shows the content rate of oxygen is 0.02- It was defined as .10.
Further, the Si component is contained for the purpose of achieving the same heat resistance improving effect as that at the highest content point of Al and oxygen, and therefore the Z value indicating the content ratio is also 0.01 to 0 for the same reason. .10.
[0012]
(C) Spacing between the highest Al and oxygen content points and the highest Ti and nitrogen content points
If the distance is less than 0.01 μm, it is difficult to clearly form each point with the above composition, and as a result, the desired excellent high-temperature hardness and heat resistance, as well as high-temperature strength can be ensured. When the distance exceeds 0.1 μm, the disadvantages of the respective points, that is, when the highest content point of Al and oxygen is insufficient, high temperature strength is insufficient, and when the highest content point of Ti and nitrogen is high temperature hardness and heat resistance The shortage appears locally in the layer, which is likely to cause thermoplastic deformation and further promotes the progress of wear. Therefore, the interval was set to 0.01 to 0.1 μm.
[0013]
(D) Overall average layer thickness of the hard coating layer
If the layer thickness is less than 1 μm, the desired wear resistance cannot be ensured. On the other hand, if the average layer thickness exceeds 15 μm, chipping tends to occur at the cutting edge. It was defined as ˜15 μm.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Next, the coated carbide tool and the manufacturing method thereof according to the present invention will be specifically described with reference to examples.
(Example 1)
WC powder, TiC powder, VC powder, TaC powder, NbC powder, Cr having an average particle diameter of 1 to 3 μm as raw material powders _Three C ₂ Powder and Co powder are prepared, and these raw material powders are blended in the blending composition shown in Table 1, wet mixed by a ball mill for 60 hours, dried, and then pressed into a compact at a pressure of 100 MPa. The green compact was sintered in a vacuum of 6 Pa at a temperature of 1420 ° C. for 1 hour, and after sintering, the cutting edge portion was subjected to a honing process of R: 0.03, whereby ISO standard / CNMG120212 Cemented carbide substrates A-1 to A-10 made of WC-based cemented carbide having a chip shape were formed.
[0015]
In addition, as raw material powder, TiCN (mass ratio of TiC / TiN = 50/50) powder having an average particle diameter of 0.5 to 2 μm, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC powder, Co powder, and Ni powder are prepared. These raw material powders are blended into the blending composition shown in Table 2 and wet mixed in a ball mill for 60 hours and dried. After that, the green compact was press-molded into a green compact at a pressure of 100 MPa, and this green compact was sintered in a nitrogen atmosphere of 2 kPa at a temperature of 1520 ° C. for 1 hour. : By performing a honing process of 0.03, cemented carbide substrates B-1 to B-6 made of TiCN-based cermets having a chip shape of ISO standard / CNMG120412 were formed.
[0016]
Next, each of the above-mentioned carbide substrates A-1 to A-10 and B-1 to B-6 was ultrasonically cleaned in acetone and dried, and then in the arc ion plating apparatus shown in FIG. The rotary table is eccentrically mounted at a position away from the central axis of the rotary table in a radial direction so that it can rotate freely. Both of them have the highest content of Al and oxygen with various component compositions as cathode electrodes (evaporation sources). The point-forming Al—Ti—Si alloy, Ti having various component compositions, and the highest nitrogen content point-forming Ti—Al—Si alloy are arranged to face each other across the rotary table, and each of the Al—Ti An intermediate Al / Ti / Si alloy and an intermediate Ti / Al / Si alloy that have a lower Al content compared to the Si alloy and a lower Ti content than the Ti-Al-Si alloy The bombard cleaning metal Ti is also installed, and the inside of the apparatus is first evacuated and kept at a vacuum of 0.5 Pa or less, and the inside of the apparatus is heated to 500 ° C. with a heater and then rotated on the rotary table. A DC bias voltage of −1000 V is applied to the rotating carbide substrate while rotating, and an arc discharge is generated by flowing a current of 100 A between the metal Ti and the anode electrode of the cathode electrode. Then, a DC bias voltage of −30 V is applied to the carbide substrate rotating while rotating on the rotary table, and each cathode electrode (Al—Ti—Si for forming the Al and oxygen highest content point is applied). Alloy, Ti—Al—Si alloy for forming the highest content point of Ti and nitrogen, and intermediate Al / Ti / Si alloy and intermediate Ti / Al / Si composite ) And the anode electrode, an arc discharge is caused to flow between them and the pressure of the reaction atmosphere in the apparatus is maintained at 3 Pa, while the carbide substrate has a relatively high Al content. The reaction atmosphere at the point of time closest to the cathode electrode (evaporation source) of the Al—Ti—Si alloy is the reaction atmosphere having the highest oxygen introduction ratio and the lowest nitrogen introduction ratio, while the cemented carbide substrate is In particular, the reaction atmosphere at the point of time closest to the cathode electrode of the Ti-Al-Si alloy having a high Ti content ratio is the reaction atmosphere having the highest nitrogen introduction ratio and the lowest oxygen introduction ratio. The cathode electrode closest position of the Ti-Al-Si alloy through the cathode electrode closest position of the intermediate Al / Ti / Si alloy from the cathode electrode closest position of the Al-Ti-Si alloy The reaction atmosphere during the rotational movement is a continuously changing atmosphere in which the oxygen introduction rate continuously decreases and the nitrogen introduction rate continuously increases correspondingly, while the carbide substrate is the Ti-Al- Nitrogen is introduced into the reaction atmosphere during the rotational movement from the Si alloy cathode electrode closest position to the Al-Ti-Si alloy cathode electrode closest position via the intermediate Ti / Al / Si alloy cathode electrode closest position. The method of the present invention was carried out under the condition of a continuously changing atmosphere in which the ratio was continuously decreased and the oxygen introduction ratio was continuously increased correspondingly. Accordingly, the surface of the cemented carbide substrate was aligned along the thickness direction. Al and oxygen highest content points and Ti and nitrogen highest content points of the target compositions shown in Tables 3 and 4 are alternately present at the target intervals shown in Tables 3 and 4, and the Al and oxygen highest points Including The component concentration distribution structure in which the content ratios of Al, oxygen, and Ti and nitrogen continuously change from the point Ti to the highest point of nitrogen and the point of highest Ti and nitrogen to the point of highest content of Al and oxygen, respectively. In addition, a throwaway tip made of the surface-coated cemented carbide of the present invention as a coated carbide tool of the present invention formed by vapor-depositing a hard coating layer having a target total layer thickness shown in Tables 3 and 4 (hereinafter referred to as the present coated 1 to 16 were manufactured.
[0017]
For comparison purposes, these carbide substrates A-1 to A-10 and B-1 to B-6 were ultrasonically cleaned in acetone and dried, and each of the ordinary arcs shown in FIG. Installed in an ion plating device, equipped with Ti-Al-Si alloys with various component compositions as cathode electrodes (evaporation sources), and further equipped with metallic Ti for bombard cleaning. First, the interior of the device was evacuated. The inside of the apparatus is heated to 500 ° C. with a heater while maintaining a vacuum of 0.5 Pa or less, and then a −1000 V DC bias voltage is applied to the cemented carbide substrate, and the metal Ti and anode electrode of the cathode electrode are applied. A current of 100 A was passed between them to generate an arc discharge to clean the surface of the carbide substrate with Ti bombard, and then introduced nitrogen gas as a reaction gas into the apparatus to make a reaction atmosphere of 2 Pa, The conventional method was carried out under the condition that a DC bias voltage of −100 V was applied to the hard substrate and a current of 100 A was passed between the Ti—Al—Si alloy of the cathode electrode and the anode electrode to generate arc discharge. Each of the surfaces of the cemented carbide substrates A-1 to A-10 and B-1 to B-6 has the target composition and target layer thickness shown in Tables 5 and 6, and substantially along the layer thickness direction. Conventional surface-coated cemented carbide throwaway tip (hereinafter referred to as conventional coated carbide) as a conventional coated carbide tool formed by vapor deposition of a hard coating layer consisting of a (Ti, Al, Si) N layer that does not change in composition. Chips) 1 to 16 were produced.
[0018]
Next, the coated carbide chips 1 to 16 and the coated carbide chips 1 to 16 of the present invention obtained by the method of the present invention and the conventional method are screwed to the tip of the tool steel tool with a fixing jig. In state,
Work material: JIS / SUS316 round bar,
Cutting speed: 250 m / min. ,
Incision: 1.5mm,
Feed: 0.20 mm / rev. ,
Cutting time: 10 minutes,
Stainless steel dry continuous high speed cutting test under the conditions of
Work material: JIS / SUS304 lengthwise equidistant four round grooved round bars,
Cutting speed: 220 m / min. ,
Incision: 1.5mm,
Feed: 0.20 mm / rev. ,
Cutting time: 5 minutes
Stainless steel dry interrupted high-speed cutting test under the conditions of
Work material: JIS-S15C lengthwise equal length 4 round grooved round bar,
Cutting speed: 320 m / min. ,
Cutting depth: 2.0 mm
Feed: 0.25 mm / rev. ,
Cutting time: 5 minutes
The dry interrupted high-speed cutting test of mild steel under the above conditions was conducted, and the flank wear width of the cutting edge was measured in any cutting test. The measurement results are shown in Tables 5-6.
[0019]
[Table 1]

[0020]
[Table 2]

[0021]
[Table 3]

[0022]
[Table 4]

[0023]
[Table 5]

[0024]
[Table 6]

[0025]
(Example 2)
As raw material powders, medium coarse WC powder having an average particle diameter of 5.5 μm, fine WC powder of 0.8 μm, TaC powder of 1.3 μm, NbC powder of 1.2 μm, ZrC of 1.2 μm Powder, 2.3 μm Cr _Three C ₂ Prepared powder, 1.5 μm VC powder, 1.0 μm (Ti, W) C [mass ratio, TiC / WC = 50/50] powder, and 1.8 μm Co powder. Each powder was blended in the blending composition shown in Table 7, added with wax, ball mill mixed in acetone for 60 hours, dried under reduced pressure, and then pressed into various compacts of a predetermined shape at a pressure of 100 MPa, These green compacts were heated to a predetermined temperature in the range of 1370 to 1470 ° C. at a rate of temperature increase of 7 ° C./min in a vacuum atmosphere of 6 Pa, kept at this temperature for 1 hour, and then subjected to furnace cooling conditions. In order to form three types of cemented carbide substrate-forming round bar sintered bodies having diameters of 8 mm, 13 mm, and 26 mm, and further grinding from the above three types of round bar sintered bodies, In the combinations shown in Table 7, the diameter x length of the cutting edge is 6 each. m × 13mm, 10mm × 22mm, and dimensions of 20 mm × 45 mm, as well as any twist angle: 30 degrees carbide substrate having a 4 flute square shape (end mills) C-1 through C-8 were prepared, respectively.
[0026]
Then, the surfaces of these carbide substrates (end mills) C-1 to C-8 were ultrasonically cleaned in acetone and dried, and then charged into the arc ion plating apparatus shown in FIG. The method of the present invention was carried out under the same conditions as in Example 1 above, so that on the surface of the cemented carbide substrate (end mill) along the thickness direction, Al and oxygen highest content points and Ti of the target composition shown in Table 8 And the nitrogen highest content point alternately and repeatedly at the target intervals shown in Table 8, and from the Al and oxygen highest content point to the Ti and nitrogen highest content point, from the Ti and nitrogen highest content point to the Al In addition, a hard coating layer having a target total layer thickness as shown in Table 8 having a component concentration distribution structure in which the content ratios of Al, oxygen and Ti and nitrogen continuously change to the highest oxygen content point is deposited. Forms of the present invention coated cemented carbide end mills 1 to 8 as the present invention coated cemented carbide comprising manufactured.
[0027]
For the purpose of comparison, the above-mentioned carbide substrates (end mills) C-1 to C-8 are ultrasonically cleaned in acetone and dried, and the ordinary arc ion plating apparatus shown in FIG. 2 is also used. The conventional method was carried out under the same conditions as in Example 1 above, so that the target composition and target layer thickness shown in Table 9 were obtained, and the composition change substantially along the layer thickness direction. Conventional surface-coated cemented carbide end mills (hereinafter referred to as conventional coated carbide end mills) 1 to 8 as conventional coated carbide tools formed by vapor-depositing a hard coating layer comprising no (Ti, Al, Si) N layer Were manufactured respectively.
[0028]
Next, among the coated carbide end mills 1 to 8 and the conventional coated carbide end mills 1 to 8 obtained by the method of the present invention and the conventional method, the coated carbide end mills 1 to 3 and the conventional coated carbide of the present coated carbide. For end mills 1 to 3,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / SUS304 plate,
Cutting speed: 80 m / min. ,
Axial cut: 6mm,
Radial incision: 0.6mm,
Table feed: 320 mm / min,
About the wet high-speed side cutting test of stainless steel under the above conditions, the present invention coated carbide end mills 4 to 6 and the conventional coated carbide end mills 4 to 6 obtained by the above-described method of the present invention and the conventional method,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / S15C plate,
Cutting speed: 160 m / min. ,
Axial cut: 8mm,
Radial notch: 1mm,
Table feed: 600 mm / min,
The wet coated high-speed side cutting test of mild steel under the conditions of the present invention, the present invention and the conventional coated carbide end mills 7 and 8 and the conventional coated carbide end mills 7 and 8 obtained by the conventional method,
Work material: Plane size: 100 mm × 250 mm, thickness: 50 mm JIS / SUS316 plate material,
Cutting speed: 75 m / min. ,
Axial cut: 15mm,
Radial notch: 2mm,
Table feed: 300mm / min,
The wet high-speed side cutting test of stainless steel under the conditions of The cutting length up to 0.1 mm was measured. The measurement results are shown in Tables 8 and 9, respectively.
[0029]
[Table 7]

[0030]
[Table 8]

[0031]
[Table 9]

[0032]
(Example 3)
The diameters produced in Example 2 above were 8 mm (for forming carbide substrates C-1 to C-3), 13 mm (for forming carbide substrates C-4 to C-6), and 26 mm (for carbide substrates C-). 7, for C-8 formation), from these three types of round bar sintered bodies, the diameter x length of the groove forming portion is 4 mm x 13 mm (by grinding), respectively. Carbide substrates D-1 to D-3), 8 mm × 22 mm (Carbide substrates D-4 to D-6), and 16 mm × 45 mm (Carbide substrates D-7 and D-8), and all Carbide substrates (drills) D-1 to D-8 having a two-blade shape with a twist angle of 30 degrees were produced.
[0033]
Next, the cutting edges of these carbide substrates (drills) D-1 to D-8 are subjected to honing, ultrasonically cleaned in acetone and dried, and the arc ion plating apparatus shown in FIG. 1 is also used. Then, the method of the present invention was carried out under the same conditions as in Example 1 above, so that Al and oxygen having the target composition shown in Table 10 along the thickness direction were formed on the surface of the carbide substrate (drill). The highest content point and the highest Ti and nitrogen content point are alternately repeated at the target intervals shown in Table 10, and from the highest Al and oxygen content point, the highest Ti and nitrogen content point, and the highest Ti and nitrogen content The component concentration distribution structure in which the content ratios of Al, oxygen, and Ti and nitrogen continuously change from the point to the Al and oxygen maximum content point, respectively, and the hardness of the target total layer thickness is also shown in Table 10 The present invention coated cemented carbide drills 1-8 each coating layer as the present invention coated cemented carbide comprising depositing formed was produced.
[0034]
For comparison purposes, the cutting edges of the above-mentioned carbide substrates (drills) D-1 to D-8 are honed, ultrasonically cleaned in acetone, and dried, as shown in FIG. A conventional arc ion plating apparatus was charged and the conventional method was carried out under the same conditions as in Example 1. Thus, the target composition and the target layer thickness shown in Table 11 were obtained, and along the layer thickness direction. Conventional surface-coated cemented carbide drills (hereinafter referred to as conventional coated carbide) as a conventional coated carbide tool formed by vapor-depositing a hard coating layer consisting of a (Ti, Al, Si) N layer with substantially no composition change. (Referred to as drills) 1 to 8 were produced.
[0035]
Next, among the coated carbide drills 1 to 8 and the conventional coated carbide drills 1 to 8 obtained by the method of the present invention and the conventional method, the coated carbide drills 1 to 3 and the conventional coated carbide of the present invention. For drills 1-3,
Work material: Plane dimension: 100 mm × 250, thickness: 50 mm JIS / S15C plate,
Cutting speed: 140 m / min. ,
Feed: 0.14mm / rev,
Hole depth: 8mm,
With respect to the present invention coated carbide drills 4-6 and conventional coated carbide drills 4-6 obtained by the wet high-speed drilling test of mild steel under the above conditions, the above-described method of the present invention and the conventional method,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / SUS304 plate,
Cutting speed: 100 m / min. ,
Feed: 0.18mm / rev,
Hole depth: 16mm,
About the wet coated high-speed drilling test of stainless steel under the conditions of the present invention, the present invention coated carbide drills 7 and 8 and the conventional coated carbide drills 7 and 8 obtained by the present method and the conventional method,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / S15C plate,
Cutting speed: 100 m / min. ,
Feed: 0.27mm / rev,
Hole depth: 24mm
Wet high-speed high-drilling drilling test of mild steel under the above conditions, and each wet high-speed high-feed high-drilling cutting test (using water-soluble cutting oil) leads to a flank wear width of 0.3 mm on the tip cutting edge surface The number of drilling processes up to was measured. The measurement results are shown in Tables 10 and 11, respectively.
[0036]
[Table 10]

[0037]
[Table 11]

[0038]
The present coated carbide tips 1-16, the present coated carbide end mills 1-8, the present coated carbide drills 1-8, and the present coated carbide drills 1-8 as the present coated carbide tools obtained by the above method of the present invention, and the conventional About the hard coating layer which comprises the conventional coated carbide tips 1-16, the conventional coated carbide end mills 1-8, and the conventional coated carbide drills 1-8 as the conventional coated carbide tool obtained by the above method The content ratios of Al, Ti, Si, oxygen, and nitrogen were measured using an Auger spectroscopic analyzer, and the hard coating layer of the coated carbide tool of the present invention had the highest Al and oxygen content points. The highest content points of Ti and nitrogen are alternately and repeatedly present at substantially the same composition and interval as the target values, respectively, and from the highest content point of Al and oxygen, the highest content point of Ti and nitrogen, Ti and It is confirmed that the content ratio of Al and Ti and oxygen and nitrogen continuously changes from the highest content point of element to the highest content point of Al and oxygen, respectively, and the average layer of the hard coating layer. The thickness was substantially the same as the target total layer thickness. On the other hand, the hard coating layer of the conventional coated carbide tool exhibits a composition that is substantially the same as the target composition and an overall average layer thickness that is substantially the same as the target overall layer thickness, but the composition change along the thickness direction is not observed. In other words, the composition showed a homogeneous composition throughout the layer.
[0039]
【The invention's effect】
From the results shown in Tables 3 to 11, the hard coating layer obtained by the above-described method of the present invention has a relatively high temperature hardness and heat resistance in the layer thickness direction, relative to the highest content points of Al and oxygen. The highest content points of Ti and nitrogen having excellent high-temperature strength are alternately present at predetermined intervals, and the highest content point of Ti and nitrogen from the highest content point of Al and oxygen, Ti and nitrogen. A super-coating comprising an Al—Ti—Si oxynitride layer having a component concentration distribution structure in which the content ratios of Al and Ti and oxygen and nitrogen continuously change from the highest content point of Al to the highest content point of Al and oxygen, respectively Hard tools are not subject to thermoplastic deformation in the hard coating layer, even when cutting difficult-to-cut materials such as various stainless steels and mild steels with high viscosity, especially under high-speed conditions with high heat generation. (Ti, Al, Si) N obtained by the above-described conventional method, the hard coating layer having substantially no composition change along the layer thickness direction, while exhibiting normal wear and excellent wear resistance. In the conventional coated carbide tool consisting of layers, the cutting edge ridge line where the rake face and flank of the cutting edge intersect due to the high temperature hardness and insufficient heat resistance of the hard coating layer under the high-speed heavy cutting conditions. It is apparent that the service life is reached in a relatively short time since the thermoplastic deformation occurs and as a result, the progress of wear of the hard coating layer is further promoted.
As described above, according to the method of the present invention, not only cutting under normal conditions, but also cutting of difficult-to-cut materials such as various stainless steels and mild steels, especially under high speed conditions with high heat generation. Even when done, it is possible to produce coated carbide tools that exhibit excellent wear resistance over a long period of time, so that the resulting coated carbide tools can reduce the labor and energy savings of the cutting process as well as lower costs. It is possible to respond satisfactorily to conversion.
[Brief description of the drawings]
FIG. 1 shows an arc ion plating apparatus used for forming a hard coating layer constituting a coated carbide tool of the present invention, wherein (a) is a schematic plan view and (b) is a schematic front view.
FIG. 2 is a schematic explanatory view of a normal arc ion plating apparatus used to form a hard coating layer constituting a conventional coated carbide tool.

Claims

炭化タングステン基超硬合金または炭窒化チタン系サーメットからなる超硬基体の表面に、ＡｌとＴｉとＳｉの複合酸窒化物層からなる硬質被覆層を１〜１５μｍの全体平均層厚で物理蒸着してなる表面被覆超硬合金製切削工具にして、前記硬質被覆層が、層厚方向にそって、Ａｌおよび酸素の最高含有点とＴｉおよび窒素の最高含有点とが所定間隔をおいて交互に繰り返し存在し、かつ前記Ａｌおよび酸素の最高含有点から前記Ｔｉおよび窒素の最高含有点、前記Ｔｉおよび窒素の最高含有点から前記Ａｌおよび酸素の最高含有点へＡｌと酸素およびＴｉと窒素の含有割合がそれぞれ連続的に変化する成分濃度分布構造を有し、
さらに、上記Ａｌおよび酸素の最高含有点が、
組成式：（Ａｌ_1-(X+Z)Ｔｉ_XＳｉ_Z）Ｏ_1-DＮ_D（ただし、原子比で、Ｘは０．１０〜０．２５、Ｚは０．０１〜０．１０、Ｄは０．０２〜０．１０）、
上記Ｔｉおよび窒素の最高含有点が、
組成式：（Ｔｉ_1-(Y+Z)Ａｌ_YＳｉ_Z）Ｎ_1-EＯ_E（ただし、原子比で、Ｙは０．３５〜０．６０、Ｚは０．０１〜０．１０、Ｅは０．０２〜０．１０）、
を満足し、かつ隣り合う上記Ａｌおよび酸素の最高含有点と上記Ｔｉおよび窒素の最高含有点の間隔が、０．０１〜０．１μmであること、
を特徴とする高速切削条件で硬質被覆層がすぐれた耐摩耗性を発揮する表面被覆超硬合金製切削工具。Physically vapor-deposited a hard coating layer composed of a composite oxynitride layer of Al, Ti, and Si on the surface of a cemented carbide substrate composed of a tungsten carbide base cemented carbide or titanium carbonitride cermet with an overall average layer thickness of 1 to 15 μm. In the surface-coated cemented carbide cutting tool, the hard coating layer is alternately arranged with a predetermined interval between the highest content point of Al and oxygen and the highest content point of Ti and nitrogen along the layer thickness direction. Al, oxygen, and Ti and nitrogen contained repeatedly from the highest content point of Al and oxygen to the highest content point of Ti and nitrogen, and from the highest content point of Ti and nitrogen to the highest content point of Al and oxygen It has a component concentration distribution structure in which the ratio changes continuously,
Furthermore, the highest content point of Al and oxygen is
Composition _{formula: (Al 1- (X + Z} ) Ti X Si Z) O 1-D N D ( However, in atomic ratio, X is 0.10 to 0.25, Z is 0.01-0.10, D is 0.02-0.10),
The highest content point of Ti and nitrogen is
Composition formula: (Ti _{1-(Y + Z)} Al _Y Si _Z ) N ₁ -E O _E (wherein, in terms of atomic ratio, Y is 0.35 to 0.60, Z is 0.01 to 0.10, E is 0.02-0.10),
And the interval between the highest Al and oxygen content points adjacent to each other and the highest Ti and nitrogen content point is 0.01 to 0.1 μm,
This is a surface-coated cemented carbide cutting tool that exhibits excellent wear resistance under high-speed cutting conditions.

（ａ）アークイオンプレーティング装置内の回転テーブル上に、前記回転テーブルの中心軸から半径方向に離れた位置に偏心して炭化タングステン基超硬合金の超硬基体および／または炭窒化チタン系サーメットの超硬基体を自転自在に装着し、
（ｂ）また、上記回転テーブルを挟んで、いずれもカソード電極（蒸発源）として、相対的にＡｌ含有割合の高いＡｌ−Ｔｉ−Ｓｉ合金と、相対的にＴｉ含有割合の高いＴｉ−Ａｌ−Ｓｉ合金を対向配置すると共に、それぞれ前記Ａｌ−Ｔｉ−Ｓｉ合金に比してＡｌ含有割合が低く、かつ前記Ｔｉ−Ａｌ−Ｓｉ合金に比してＴｉ含有割合が低い中間Ａｌ／Ｔｉ／Ｓｉ合金および中間Ｔｉ／Ａｌ／Ｓｉ合金を同じく対向配置し、
（ｃ）上記回転テーブルを挟んで対向配置した上記のカソード電極と、前記カソード電極のそれぞれに並設されたアノード電極との間にアーク放電を発生させ、
（ｄ）上記アークイオンプレーティング装置内の反応雰囲気を酸素と窒素の混合雰囲気とするが、前記装置内への酸素と窒素の相対導入割合を上記超硬基体の回転移動位置に対応して調整して、前記超硬基体が上記の相対的にＡｌ含有量の高いＡｌ−Ｔｉ−Ｓｉ合金のカソード電極に最も接近した時点での反応雰囲気を酸素導入割合が最も高く、窒素導入割合が最も低い反応雰囲気とする一方、前記超硬基体が上記の相対的にＴｉ含有量の高いＴｉ−Ａｌ−Ｓｉ合金のカソード電極に最も接近した時点での反応雰囲気を窒素導入割合が最も高く、酸素導入割合が最も低い反応雰囲気とすると共に、前記超硬基体が前記Ａｌ−Ｔｉ−Ｓｉ合金のカソード電極最接近位置から上記中間Ａｌ／Ｔｉ／Ｓｉ合金のカソード電極最接近位置を経て前記Ｔｉ−Ａｌ−Ｓｉ合金のカソード電極最接近位置に回転移動する間の反応雰囲気を、酸素導入割合が連続的に減少し、これに対応して窒素導入割合が連続的に増加する連続変化雰囲気とし、一方前記超硬基体が前記Ｔｉ−Ａｌ−Ｓｉ合金のカソード電極最接近位置から上記中間Ｔｉ／Ａｌ／Ｓｉ合金のカソード電極最接近位置を経て前記Ａｌ−Ｔｉ−Ｓｉ合金のカソード電極最接近位置に回転移動する間の反応雰囲気を、窒素導入割合が連続的に減少し、これに対応して酸素導入割合が連続的に増加する連続変化雰囲気とし、
（ｅ）もって、上記回転テーブル上で自転しながら偏心回転する上記超硬基体の表面に、層厚方向にそって、Ａｌおよび酸素の最高含有点とＴｉおよび窒素の最高含有点とが所定間隔をおいて交互に繰り返し存在し、かつ前記Ａｌおよび酸素の最高含有点から前記Ｔｉおよび窒素の最高含有点、前記Ｔｉおよび窒素の最高含有点から前記Ａｌおよび酸素の最高含有点へＡｌと酸素およびＴｉと窒素の含有割合がそれぞれ連続的に変化する成分濃度分布構造を有するＡｌとＴｉとＳｉの複合酸窒化物層からなる硬質被覆層を物理蒸着すること、
以上（ａ）〜（ｅ）からなることを特徴とする高速切削条件で硬質被覆層がすぐれた耐摩耗性を発揮する表面被覆超硬合金製切削工具の製造方法。(A) A tungsten carbide-based cemented carbide substrate and / or a titanium carbonitride-based cermet eccentrically placed on a rotating table in an arc ion plating apparatus at a position radially away from the center axis of the rotating table. A carbide substrate is mounted to rotate freely,
(B) Further, sandwiching the rotary table, both of them are used as cathode electrodes (evaporation sources), an Al—Ti—Si alloy having a relatively high Al content, and Ti—Al— having a relatively high Ti content. An intermediate Al / Ti / Si alloy in which Si alloys are arranged opposite to each other, and the Al content is lower than that of the Al-Ti-Si alloy, and the Ti content is lower than that of the Ti-Al-Si alloy. And the intermediate Ti / Al / Si alloy is also arranged oppositely,
(C) generating an arc discharge between the cathode electrode disposed opposite to the rotary table and the anode electrode arranged in parallel with each of the cathode electrodes;
(D) The reaction atmosphere in the arc ion plating apparatus is a mixed atmosphere of oxygen and nitrogen, and the relative introduction ratio of oxygen and nitrogen into the apparatus is adjusted according to the rotational movement position of the carbide substrate. The reaction atmosphere when the cemented carbide substrate is closest to the cathode electrode of the above Al-Ti-Si alloy having a relatively high Al content has the highest oxygen introduction ratio and the lowest nitrogen introduction ratio. On the other hand, the reaction atmosphere at the time when the carbide substrate is closest to the cathode electrode of the Ti-Al-Si alloy having a relatively high Ti content has the highest nitrogen introduction ratio and the oxygen introduction ratio. Is the lowest reaction atmosphere, and the cemented carbide substrate passes through the intermediate Al / Ti / Si alloy cathode electrode closest position from the Al-Ti-Si alloy cathode electrode closest position to the T -The reaction atmosphere during the rotational movement to the closest cathode electrode of the Al-Si alloy is a continuously changing atmosphere in which the oxygen introduction rate continuously decreases and the nitrogen introduction rate continuously increases correspondingly, On the other hand, the cemented carbide substrate moves from the Ti—Al—Si alloy cathode electrode closest position to the intermediate Ti / Al / Si alloy cathode electrode closest position to the Al—Ti—Si alloy cathode electrode closest position. The reaction atmosphere during the rotational movement is a continuously changing atmosphere in which the nitrogen introduction ratio decreases continuously and the oxygen introduction ratio increases correspondingly,
(E) Therefore, along the layer thickness direction, the highest content point of Al and oxygen and the highest content point of Ti and nitrogen are arranged at predetermined intervals on the surface of the cemented carbide substrate rotating eccentrically while rotating on the rotary table. And Al and oxygen from the highest content point of Al and oxygen to the highest content point of Ti and nitrogen, from the highest content point of Ti and nitrogen to the highest content point of Al and oxygen, and Physically vapor-depositing a hard coating layer composed of a composite oxynitride layer of Al, Ti, and Si having a component concentration distribution structure in which the content ratios of Ti and nitrogen change continuously, respectively.
A method for manufacturing a surface-coated cemented carbide cutting tool that exhibits excellent wear resistance under a high-speed cutting condition characterized by comprising the above (a) to (e).