JP2004345000A - Cutting tool of surface-coated cemented carbide with hard coating layer achieving excellent abrasion resistance in high speed cutting condition, and method for manufacturing the same - Google Patents
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【０００１】
【発明の属する技術分野】
この発明は、硬質被覆層が一段とすぐれた高温硬さと耐熱性を有し、かつ高温強度にもすぐれ、したがって各種の鋼や鋳鉄などの切削加工を、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：（Ｔｉ１− ＢＹＢ）Ｎ（ただし、原子比で、Ｂは０．４０〜０．６５を示す）を満足するＴｉとＹの複合窒化物［以下、（Ｔｉ，Ｙ）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，Ｙ）Ｎ層が、Ｔｉ成分による高温強度と、Ｙ成分による高温硬さおよび耐熱性を有し、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−Ｙ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，Ｙ）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３２０５９４３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，Ｙ）Ｎ層が、すぐれた高温強度を有するものの、十分な高温硬さおよび耐熱性を具備するものでないために、前記硬質被覆層の摩耗進行が一段と促進す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、特に高速切削加工で、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Ｙ含有割合の高いＹ−Ｔｉ合金、他方側に相対的にＴｉ含有割合の高いＴｉ−Ｙ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Ｙ−Ｔｉ合金に比してＹ含有割合が低く、かつ前記Ｔｉ−Ｙ合金に比してＴｉ含有割合が低い中間Ｙ／Ｔｉ合金と中間Ｔｉ／Ｙ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Ｙ含有割合の高いＹ−Ｔｉ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−Ｙ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Ｙ−Ｔｉ合金のカソード電極最接近位置から上記中間Ｙ／Ｔｉ合金のカソード電極最接近位置を経て前記Ｔｉ−Ｙ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−Ｙ合金のカソード電極最接近位置から上記中間Ｔｉ／Ｙ合金のカソード電極最接近位置を経て前記Ｙ−Ｔｉ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、
ＹとＴｉの複合酸窒化物（以下、Ｙ−Ｔｉ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Ｙ含有量の高いＹ−Ｔｉ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Ｙ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−Ｙ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Ｙ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Ｙ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Ｙおよび酸素の最高含有点へＹ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Ｙ−Ｔｉ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Ｙ−Ｔｉ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Ｙおよび酸素の最高含有点が、
組成式：（Ｙ１− ＡＴｉＡ）Ｏ１−ＤＮＤ（ただし、原子比で、Ａは０．０５〜０．３０、Ｄは０．０２〜０．１０を示す）、
上記Ｔｉおよび窒素の最高含有点が、
組成式：（Ｔｉ１− ＢＹＢ）Ｎ１−ＥＯＥ（ただし、原子比で、Ｂは０．４０〜０．６５、Ｅは０．０２〜０．１０を示す）、
を満足し、かつ隣り合う上記Ｙ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Ｙおよび酸素の最高含有点部分では、高含有のＹと酸素の作用で、一段と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、上記の従来（Ｔｉ，Ｙ）Ｎ層におけるＴｉおよび窒素の含有割合と同等の相対的に高含有のＴｉおよび窒素含有となることから、前記従来（Ｔｉ，Ｙ）Ｎ層の具備する高温強度と同等の相対的にすぐれた高温強度が確保され、かつこれらＹ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ので、層全体の特性として一段とすぐれた高温硬さと耐熱性、さらにすぐれた高温強度も具備するようになり、また前記両点間でＹ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、かかる構成のＹ−Ｔｉ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、各種の鋼や鋳鉄などの切削加工を高い発熱を伴なう高速切削条件で行なった場合にも、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、Ｙ−Ｔｉ酸窒化物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にして、前記硬質被覆層を、層厚方向にそって、Ｙ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Ｙ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Ｙおよび酸素の最高含有点へＹ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Ｙおよび酸素の最高含有点が、
組成式：（Ｙ１− ＡＴｉＢ）Ｏ１−ＤＮＤ（ただし、原子比で、Ｘは０．０５〜０．３０、Ｄは０．０２〜０．１０を示す）、
上記Ｔｉおよび窒素の最高含有点が、
組成式：（Ｔｉ１− ＢＹＢ）Ｎ１−ＥＯＥ（ただし、原子比で、Ｂは０．４０〜０．６５、Ｅは０．０２〜０．１０を示す）、
を満足し、かつ隣り合う上記Ｙ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、
硬質被覆層で構成してなる、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Ｙ含有割合の高いＹ−Ｔｉ合金と、相対的にＴｉ含有割合の高いＴｉ−Ｙ合金を対向配置すると共に、それぞれ前記Ｙ−Ｔｉ合金に比してＹ含有割合が低く、かつ前記Ｔｉ−Ｙ合金に比してＴｉ含有割合が低い中間Ｙ／Ｔｉ合金と中間Ｔｉ／Ｙ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Ｙ含有割合の高いＹ−Ｔｉ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−Ｙ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Ｙ−Ｔｉ合金のカソード電極最接近位置から上記中間Ｙ／Ｔｉ合金のカソード電極最接近位置を経て前記Ｔｉ−Ｙ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−Ｙ合金のカソード電極最接近位置から上記中間Ｔｉ／Ｙ合金のカソード電極最接近位置を経て前記Ｙ−Ｔｉ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、Ｙ−Ｔｉ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Ｙ−Ｔｉ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）Ｙおよび酸素の最高含有点
上記Ｙ−Ｔｉ酸窒化物層において、Ｙおよび酸素の最高含有点部分では高含有のＹと酸素の作用で一段とすぐれた高温硬さと耐熱性を示し、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と窒素の作用ですぐれた高温強度を示し、したがってＹおよび酸素の最高含有点では、ＴｉのＹとの合量に占める含有割合を示すＡ値が、原子比で０．０５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、Ｙおよび酸素の相対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高温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Ａ値が０．３０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ることから、Ｔｉの含有割合を示すＡ値を０．０５〜０．３０、および窒素の含有割合を示すＤ値を０．０２〜０．１０とそれぞれ定めた。
【００１１】
（ｂ）Ｔｉおよび窒素の最高含有点
上記の通りＹおよび酸素の最高含有点は一段とすぐれた高温硬さと耐熱性を有するが、反面高温強度の低いものであるため、このＹ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、ＹのＴｉとの合量に占める含有割合を示すＢ値が０．４０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、この結果硬質被覆層の摩耗進行が一段と促進するようになり、また同Ｂ値が０．６５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、Ｙの含有割合を示すＢ値を０．４０〜０．６５、酸素の含有割合を示すＥ値を０．０２〜０．１０と定めた。
【００１２】
（ｃ）Ｙ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Ｙ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、これが原因で切刃部にチッピング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、切刃部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、Ｃｒ３ Ｃ２ 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、Ｍｏ２ Ｃ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Ｙおよび酸素最高含有点形成用Ｙ−Ｔｉ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−Ｙ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Ｙ−Ｔｉ合金に比してＹ含有割合が低く、かつ前記Ｔｉ−Ｙ合金に比してＴｉ含有割合が低い中間Ｙ／Ｔｉ合金と中間Ｔｉ／Ｙ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Ｙおよび酸素最高含有点形成用Ｙ−Ｔｉ合金、前記Ｔｉおよび窒素最高含有点形成用Ｔｉ−Ｙ合金、さらに前記中間Ｙ／Ｔｉ合金および中間Ｔｉ／Ｙ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Ｙ含有割合の高いＹ−Ｔｉ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−Ｙ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Ｙ−Ｔｉ合金のカソード電極最接近位置から上記中間Ｙ／Ｔｉ合金のカソード電極最接近位置を経て前記Ｔｉ−Ｙ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−Ｙ合金のカソード電極最接近位置から上記中間Ｔｉ／Ｙ合金のカソード電極最接近位置を経て前記Ｙ−Ｔｉ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Ｙ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Ｙ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Ｙおよび酸素最高含有点へＹ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−Ｙ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−Ｙ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，Ｙ）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・ＳＮＣＭ４３９の丸棒、
切削速度：３８０ｍ／ｍｉｎ．、
切り込み：１．５ｍｍ、
送り：０．２ｍｍ／ｒｅｖ．、
切削時間：１０分、
の条件での合金鋼の乾式連続高速切削加工試験、
被削材：ＪＩＳ・ＦＣ２５０の長さ方向等間隔４本縦溝入り丸棒、
切削速度：４００ｍ／ｍｉｎ．、
切り込み：２ｍｍ、
送り：０．３ｍｍ／ｒｅｖ．、
切削時間：５分、
の条件での鋳鉄の乾式断続高速切削加工試験、さらに、
被削材：ＪＩＳ・Ｓ５０Ｃの丸棒、
切削速度：３５０ｍ／ｍｉｎ．、
切り込み：１．５ｍｍ、
送り：０．２ｍｍ／ｒｅｖ．、
切削時間：５分、
の条件での炭素鋼の乾式連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６に示した。
【００１９】
【表１】
【表２】
【表３】
【表４】
【表５】
【表６】
（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Ｙ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Ｙ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Ｙおよび酸素最高含有点へＹ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，Ｙ）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・Ｓ５０Ｃの板材、
切削速度：１６０ｍ／ｍｉｎ．、
軸方向切り込み：８ｍｍ、
径方向切り込み：１．２ｍｍ、
テーブル送り：６５０ｍｍ／分、
の条件での炭素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・ＳＫＤ６１（硬さ：ＨＲＣ５２）の板材、
切削速度：４５ｍ／ｍｉｎ．、
軸方向切り込み：８ｍｍ、
径方向切り込み：０．５ｍｍ、
テーブル送り：１５０ｍｍ／分、
の条件での工具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・ＳＣＭ４４０の板材、
切削速度：６０ｍ／ｍｉｎ．、
軸方向切り込み：２４ｍｍ、
径方向切り込み：４ｍｍ、
テーブル送り：３５０ｍｍ／分、
の条件での合金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】
【表８】
【表９】
（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Ｙ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Ｙ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Ｙおよび酸素最高含有点へＹ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，Ｙ）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・ＳＮＣＭ４３９の板材、
切削速度：２００ｍ／ｍｉｎ．、
送り：０．１５ｍｍ／ｒｅｖ、
穴深さ：８ｍｍ、
の条件での合金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・Ｓ５５Ｃの板材、
切削速度：１２０ｍ／ｍｉｎ．、
送り：０．２５ｍｍ／ｒｅｖ、
穴深さ：１６ｍｍ、
の条件での炭素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・ＳＫＤ６１（硬さ：ＨＲＣ５２）の板材、
切削速度：２０ｍ／ｍｉｎ．、
送り：０．１８ｍｍ／ｒｅｖ、
穴深さ：２４ｍｍ、
の条件での工具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】
【表１１】
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Ｙ、Ｔｉ、酸素、および窒素の含有割合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、Ｙ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Ｙ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Ｙおよび酸素の最高含有点へＹ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ことが確認され、さらに硬質被覆層の平均層厚も目標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、相対的に一段とすぐれた高温硬さと耐熱性を有するＹ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Ｙ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Ｙおよび酸素の最高含有点へＹ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Ｙ−Ｔｉ酸窒化物層からなる被覆超硬工具は、いずれも切削加工を、特に高い発熱を伴う高速条件で行なった場合にも、すぐれた耐摩耗性を示し、長期に亘ってすぐれた切削性能を発揮するのに対して、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，Ｙ）Ｎ層からなる従来被覆超硬工具においては、前記の高速切削条件では、前記硬質被覆層の高温硬さおよび耐熱性不足が原因で、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、各種の鋼や鋳鉄などの通常の条件での切削加工は勿論のこと、特に高い発熱を伴う高速切削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]
TECHNICAL FIELD OF THE INVENTION
According to the present invention, the hard coating layer has a further excellent high-temperature hardness and heat resistance, and also has an excellent high-temperature strength. Therefore, cutting of various steels and cast irons is performed under high-speed processing conditions with particularly high heat generation. The present invention relates to a cutting tool made of a surface-coated cemented carbide in which a hard coating layer exhibits excellent wear resistance (hereinafter referred to as a coated cemented carbide tool) and a method of manufacturing the same.
[0002]
[Prior art]
In general, coated carbide tools include throw-away inserts, which are detachably attached to the tip of a cutting tool for turning or planing of various materials such as steel or cast iron, and drilling of the material. Drills and miniature drills used for processing and the like, there are solid type end mills and the like used for face machining and grooving, shoulder machining and the like of the work material, and the solid is provided by detachably attaching the throw-away tip. 2. Description of the Related Art A throw-away end mill tool or the like that performs a cutting process like a type end mill is known.
[0003]
Further, as a coated cemented 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-based cemented carbide (hereinafter, these cemented carbide substrates) Are collectively referred to as “super-hard substrate”).
Formula: (Ti 1- B Y B) N ( provided that an atomic ratio, B indicates a 0.40 to 0.65) composite nitride of Ti and Y satisfying the following, (Ti, Y) N ], A coated hard carbide layer formed by physical vapor deposition of a hard coating layer having an average layer thickness of 1 to 15 μm is proposed, and the coated hard metal tool constitutes the hard coating layer (Ti, Y). It is also known that the N layer has high-temperature strength due to the Ti component, high-temperature hardness and heat resistance due to the Y component, and is used for continuous cutting and intermittent cutting of various steels and cast irons (for example, Patent Documents). 1).
[0004]
Furthermore, the above-mentioned coated carbide tool is charged with the above-mentioned carbide substrate in an arc ion plating apparatus, which is a kind of physical vapor deposition apparatus shown schematically in FIG. 2, for example, and the inside of the apparatus is heated by a heater. For example, an arc discharge is generated between an anode electrode and a cathode electrode (evaporation source) on which a Ti-Y alloy having a predetermined composition is set under a condition of, for example, a current of 90 A while being heated to a temperature of 500 ° C. At the same time, a 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, on the surface of the cemented carbide substrate, a bias voltage of, for example, -100 V is applied, and It is also well known that it is manufactured by depositing a hard coating layer composed of a (Ti, Y) N layer. (For example, see Patent Document 1).
[0005]
[Patent Document 1]
Japanese Patent No. 3205943 [0006]
[Problems to be solved by the invention]
In recent years, the performance of cutting equipment has been remarkably improved.On the other hand, there is a strong demand for labor saving, energy saving, and lower cost for cutting, and with this trend, there has been a tendency to require cutting under even higher speed conditions. However, in the above-mentioned conventional coated cemented carbide tool, when the cutting process is performed under high-speed conditions with particularly high heat generation, the (Ti, Y) N layer as the hard coating layer is excellent. Although it has high-temperature strength, it does not have sufficient high-temperature hardness and heat resistance, so that the progress of abrasion of the hard coating layer is further promoted. It is the current situation.
[0007]
[Means for Solving the Problems]
In view of the above, the present inventors have paid particular attention to the hard coating layer of the conventional coated carbide tool described above, and have developed a hard coating layer that exhibits excellent wear resistance, particularly in high-speed cutting. As a result of conducting research,
(A) For example, an arc ion plating apparatus belonging to a physical vapor deposition apparatus having a structure shown in a schematic plan view in FIG. 1A and a schematic front view in FIG. A table is provided, and a Y-Ti alloy having a relatively high Y content is provided on one side and a Ti-Y alloy having a relatively high Ti content is provided on one side with the rotary table interposed therebetween. ), An intermediate Y / Ti alloy and an intermediate Ti / Y alloy each having a lower Y content than the Y-Ti alloy, and a lower Ti content than the Ti-Y alloy. Is also used as a cathode electrode (evaporation source) using an arc ion plating device arranged facing
On the rotary table of this device, the carbide substrate is mounted eccentrically at a position radially away from the center axis of the rotary table,
In this state, the reaction atmosphere in the apparatus is a mixed atmosphere of oxygen and nitrogen, and the relative introduction ratio of the oxygen and nitrogen into the apparatus is adjusted in accordance with the rotational movement position of the cemented carbide substrate. The reaction atmosphere at the time when the hard substrate comes closest to the cathode electrode of the Y-Ti alloy having a relatively high Y content is defined as having the highest oxygen introduction ratio and the lowest nitrogen introduction ratio, preferably the relative oxygen introduction. While the reaction atmosphere is 90 to 97% by volume and the remainder is made of nitrogen, the reaction at the time when the cemented carbide substrate is closest to the cathode electrode of the Ti—Y alloy having a relatively high Ti content is performed. The atmosphere has the highest nitrogen introduction ratio and the lowest oxygen introduction ratio, desirably a relative nitrogen introduction ratio of 90 to 97% by volume, and a reaction atmosphere consisting of oxygen with the balance being the same. Ti alloy The reaction atmosphere during the rotational movement from the cathode electrode closest position to the Ti—Y alloy cathode electrode closest position through the intermediate Y / Ti alloy cathode electrode closest position is continuously reduced in the oxygen introduction ratio. In response to this, a continuous change atmosphere in which the introduction ratio of nitrogen is continuously increased is provided, while the cemented carbide substrate is moved from the closest position of the cathode electrode of the Ti—Y alloy to the cathode electrode of the intermediate Ti / Y alloy. In the reaction atmosphere during the rotational movement to the closest position of the Y-Ti alloy cathode electrode through the approach position, the introduction rate of nitrogen is continuously reduced, and the introduction rate of oxygen is continuously increased correspondingly. A continuous change atmosphere
While rotating the rotary table and rotating the superhard substrate itself for the purpose of equalizing the thickness of the hard coating layer formed by vapor deposition, the rotation between the cathode electrode (evaporation source) and the anode electrode is performed. Under the condition that an arc discharge occurs,
When a composite oxynitride of Y and Ti (hereinafter referred to as Y-Ti oxynitride) layer is formed,
On the surface of the cemented carbide substrate, the cemented carbide substrate eccentrically disposed at a position radially away from the center axis on the rotary table is a Y-Ti alloy having a relatively high Y content on one side. At the point closest to the cathode electrode (evaporation source), the highest content point of Y and oxygen is formed in the layer. Since the highest content point of Ti and nitrogen is formed in the layer at the time of closest approach to the alloy cathode electrode, the rotation of the rotary table causes the highest content of Y and oxygen in the layer along the thickness direction. The points and the highest content points of Ti and nitrogen alternately and repeatedly appear at predetermined intervals, and the highest content points of Ti and nitrogen from the highest content points of Y and oxygen, and the highest content points of Y and acid from the highest content points of Ti and nitrogen. Highest content of the content points Y and oxygen and Ti nitrogen may become hard layer made of Y-Ti oxynitride layer having a component concentration distribution structure that varies each continuously is formed.
[0008]
(B) In the formation of the Y-Ti oxynitride layer having the repeated and continuously changing component concentration distribution structure of the above (a), for example, the respective compositions of the cathode electrodes (evaporation sources) arranged opposite to each other and the reaction which continuously changes in the apparatus While adjusting the composition of the atmosphere, that is, the inter-introduction ratio of oxygen and nitrogen, and controlling the rotation speed of the turntable on which the carbide substrate is mounted,
The maximum content of the above Y and oxygen is
Composition formula: (Y 1 -A Ti A ) O 1 -D N D (however, A represents 0.05 to 0.30 and D represents 0.02 to 0.10 in atomic ratio),
The maximum content of Ti and nitrogen is
Formula: (Ti 1- B Y B) N 1-E O E ( However, in atomic ratio, B is .40-0.65, E represents a 0.02 to 0.10),
And the interval between the adjacent highest content points of Y and oxygen and the highest content points of Ti and nitrogen is 0.01 to 0.1 μm,
The highest Y and oxygen content points show much higher high-temperature hardness and heat resistance due to the action of the higher Y and oxygen contents, while the highest Ti and nitrogen content points show the conventional (Ti, Y) Since the content of Ti and nitrogen is relatively high, which is equivalent to the content ratio of Ti and nitrogen in the N layer, it is relatively excellent, equivalent to the high-temperature strength of the conventional (Ti, Y) N layer. High temperature strength, and the interval between the highest content point of Y and oxygen and the highest content point of Ti and nitrogen is extremely small, so that the properties of the whole layer are further improved in high temperature hardness and heat resistance, and further excellent. The hard coating layer also has high-temperature strength, and the content ratios of Y and oxygen and Ti and nitrogen continuously change (component concentration distribution structure) between the two points. Therefore, a coated carbide tool having a Y-Ti oxynitride layer having such a configuration formed as a hard coating layer requires high heat generation for cutting various kinds of steel and cast iron. The hard coating layer exhibits excellent abrasion resistance even under high-speed cutting conditions.
The research results shown in (a) and (b) above were obtained.
[0009]
The present invention has been made based on the above research results,
(1) On a surface of a super-hard substrate, a hard coating layer made of a Y-Ti oxynitride layer is physically deposited with an average layer thickness of 1 to 15 μm to form a coated super-hard tool, and the hard coating layer is formed as a layer. Along the thickness direction, the maximum content points of Y and oxygen and the maximum content points of Ti and nitrogen are alternately and repeatedly present at predetermined intervals, and the maximum content points of Y and oxygen are determined from the maximum content points of Y and oxygen. Content point, from the highest content point of the Ti and nitrogen to the highest content point of the Y and oxygen has a component concentration distribution structure in which the content ratios of Y and oxygen and Ti and nitrogen respectively continuously change,
Further, the maximum content point of Y and oxygen is
Composition formula: (Y 1 -A Ti B ) O 1 -D N D (where X represents 0.05 to 0.30 and D represents 0.02 to 0.10 in atomic ratio),
The maximum content of Ti and nitrogen is
Formula: (Ti 1- B Y B) N 1-E O E ( However, in atomic ratio, B is .40-0.65, E represents a 0.02 to 0.10),
And the interval between the adjacent highest content points of Y and oxygen and the highest content points of Ti and nitrogen is 0.01 to 0.1 μm,
A coated cemented carbide tool consisting of a hard coating layer that exhibits excellent wear resistance under high-speed cutting conditions.
(2) (a) On a rotary table in an arc ion plating apparatus, a carbide substrate is eccentrically mounted at a position radially distant from a center axis of the rotary table, and is rotatably mounted on the rotary table.
(B) In addition, a Y-Ti alloy having a relatively high Y content and a Ti-Y alloy having a relatively high Ti content are opposed to each other as a cathode electrode (evaporation source) across the rotary table. And an intermediate Y / Ti alloy and an intermediate Ti / Y alloy each having a lower Y content ratio than the Y-Ti alloy and a lower Ti content ratio than the Ti-Y alloy. And
(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 at the time when the cemented carbide substrate is closest to the cathode electrode of the Y-Ti alloy having a relatively high Y content is defined as a reaction atmosphere having the highest oxygen introduction rate and the lowest 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—Y alloy having a relatively high Ti content is a reaction atmosphere in which the nitrogen introduction rate is the highest and the oxygen introduction rate is the lowest. In addition to the atmosphere, the cemented carbide substrate is closest to the Ti-Y alloy cathode electrode from the Y-Ti alloy cathode electrode closest position to the intermediate Y / Ti alloy cathode electrode closest position. The reaction atmosphere during the rotational movement is a continuously changing atmosphere in which the oxygen introduction ratio is continuously reduced and the nitrogen introduction ratio is correspondingly continuously increased. The reaction atmosphere during the rotational movement from the alloy cathode electrode closest position through the intermediate Ti / Y alloy cathode electrode closest position to the Y-Ti alloy cathode electrode closest position is continuously changed by the nitrogen introduction ratio. A Y-Ti oxynitride layer is formed on the surface of the cemented carbide substrate, which is reduced and the oxygen introduction ratio is correspondingly continuously increased and the eccentric rotation is performed while rotating on the rotary table. Physical vapor deposition of a hard coating layer consisting of
A method for producing a coated cemented carbide tool in which the hard coating layer exhibits excellent wear resistance under high-speed cutting conditions by the steps (a) to (e).
The above features (1) and (2) are characteristic.
[0010]
Next, the reason why the configuration of the Y-Ti oxynitride layer as the hard coating layer in the coated carbide tool of the present invention is limited as described above will be described.
(A) Maximum content of Y and oxygen In the Y-Ti oxynitride layer, the highest content of Y and oxygen exhibits much higher temperature hardness and heat resistance due to the action of high content of Y and oxygen. The highest content point of Ti and nitrogen exhibits excellent high-temperature strength due to the action of a relatively high content of Ti and nitrogen. Therefore, at the highest content point of Y and oxygen, the content of Ti relative to the total amount of Y is high. The A value indicating the ratio is less than 0.05 in atomic ratio, and the D value indicating the content ratio of nitrogen to the total amount of oxygen is less than 0.02 in the same atomic ratio (hereinafter the same). In this case, the relative proportions of Y and oxygen become too large, and the high temperature strength of the layer itself is extremely low even when the highest content points of Ti and nitrogen having excellent high temperature strength are present adjacent to each other, resulting in chipping. Easily occur On the other hand, if the A value exceeds 0.30 or the D value exceeds 0.10, the high-temperature hardness and heat resistance sharply decrease and cause abrasion acceleration. The A value indicating the ratio was determined as 0.05 to 0.30, and the D value indicating the nitrogen content ratio was determined as 0.02 to 0.10.
[0011]
(B) The highest content points of Ti and nitrogen As described above, the highest content points of Y and oxygen have more excellent high-temperature hardness and heat resistance, but have a low high-temperature strength. In order to compensate for the insufficient high-temperature strength of the points, the highest content points of Ti and nitrogen having relatively excellent high-temperature strength are alternately interposed in the thickness direction. However, if the B value indicating the content ratio of Y to the total amount of Ti is less than 0.40, desired high-temperature hardness and heat resistance cannot be secured, and as a result, the wear of the hard coating layer further increases. When the B value exceeds 0.65, the high-temperature strength sharply decreases, and chipping easily occurs in the hard coating layer. On the other hand, the content ratio of oxygen to the total amount of nitrogen and nitrogen is reduced. When the E value shown is less than 0.02, the high-temperature hardness and heat resistance at the highest content points of Ti and nitrogen rapidly decrease, which causes accelerated wear, and when the E value exceeds 0.10, Since the high-temperature strength sharply drops and causes chipping, the B value indicating the Y content ratio is set to 0.40 to 0.65, and the E value indicating the oxygen content is set to 0.02 to 0. 10 was determined.
[0012]
(C) Interval between the highest content point of Y and oxygen and the highest content point of Ti and nitrogen If the interval is less than 0.01 μm, it is difficult to clearly form each point with the above composition. It is impossible to ensure the desired high-temperature hardness and heat resistance as well as high-temperature strength, and if the distance exceeds 0.1 μm, the disadvantages of each point, that is, the maximum content of Y and oxygen, If the high-temperature strength is insufficient, and if the content of Ti and nitrogen is the highest, the high-temperature hardness and heat resistance insufficiently appear locally in the layer, and as a result, chipping easily occurs in the cutting edge portion, and wear progresses further. The interval was determined to be 0.01 to 0.1 μm because it was promoted.
[0013]
(D) Average thickness of the hard coating layer If the average 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 occurs at the cutting edge. The average layer thickness was determined to be 1 to 15 μm because it was easier.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, the coated cemented carbide tool of the present invention and a method for manufacturing the same will be described in detail with reference to examples.
(Example 1)
As raw material powders, WC powder, TiC powder, VC powder, TaC powder, NbC powder, Cr 3 C 2 powder, and Co powder each having an average particle diameter of 1 to 3 μm were prepared. The mixture was wet-mixed with a ball mill for 60 hours, dried, and then pressed into a green compact at a pressure of 100 MPa, and the green compact was heated at a temperature of 1420 ° C. for 1 hour in a vacuum of 6 Pa. By sintering under the condition of holding, and after sintering, the cutting edge portion is subjected to honing processing of R: 0.03, whereby a cemented carbide substrate A made of a WC-based cemented carbide having a chip shape of ISO standard CNMG120412. -1 to A-10 were formed.
[0015]
Further, as raw material powders, TiCN (TiC / TiN = 50/50 by mass ratio) powder, Mo 2 C powder, ZrC powder, NbC powder, TaC powder, WC powder each having an average particle diameter of 0.5 to 2 μm , Co powder, and Ni powder are prepared, and these raw material powders are blended in the blending composition shown in Table 2, wet-mixed in a ball mill for 60 hours, dried, and then pressed into a green compact at a pressure of 100 MPa. The green compact was sintered in a nitrogen atmosphere of 2 kPa at a temperature of 1520 ° C. for 1 hour, and after sintering, the cutting edge was subjected to a honing process of R: 0.03 to obtain an ISO standard. -Carbide bases B-1 to B-6 made of TiCN-based cermet having a chip shape of CNMG120412 were formed.
[0016]
Next, each of the above-mentioned super-hard substrates A-1 to A-10 and B-1 to B-6 is subjected to ultrasonic cleaning in acetone, and dried, in an arc ion plating apparatus shown in FIG. Are mounted eccentrically at a position radially distant from the center axis of the rotary table and rotatably mounted on the rotary table. Both of them have the maximum Y and oxygen contents having various component compositions as cathode electrodes (evaporation sources). A Y-Ti alloy for forming a point and a Ti-Y alloy for forming a highest content point of Ti and nitrogen, which also have various component compositions, are opposed to each other with the rotary table interposed therebetween. The intermediate Y / Ti alloy and the intermediate Ti / Y alloy having a low Y content and a low Ti content as compared with the Ti-Y alloy are similarly arranged to face each other, and a metal Ti for bombarding is also mounted. While the chamber was evacuated and maintained at a vacuum of 0.5 Pa or less, the inside of the apparatus was heated to 500 ° C. with a heater, and then a DC bias voltage of −1000 V was applied to the superhard substrate rotating while rotating on the rotary table. And discharge an electric current of 100 A between the metal Ti of the cathode electrode and the anode electrode to generate an arc discharge, thereby cleaning the surface of the cemented carbide substrate with Ti bomber, and then rotating on the rotary table while rotating. A DC bias voltage of -30 V is applied to the rotating carbide substrate, and the respective cathode electrodes (the Y and the Y-Ti alloy for forming the highest oxygen content point, the Ti and the Ti-Y alloy for forming the highest nitrogen content point, Further, a current of 150 A flows between the intermediate Y / Ti alloy and the intermediate Ti / Y alloy) and the anode electrode to generate an arc discharge, and to generate an arc discharge in the apparatus. While maintaining the pressure of the atmosphere at 3 Pa, the reaction atmosphere at the time when the cemented carbide substrate was closest to the cathode electrode (evaporation source) of the Y-Ti alloy having a relatively high Y content was changed to the oxygen introduction rate. While the reaction atmosphere having the highest nitrogen introduction ratio is the lowest, the reaction atmosphere at the time when the cemented carbide substrate is closest to the cathode electrode of the Ti-Y alloy having a relatively high Ti content is defined as the nitrogen introduction ratio. Is the highest in the reaction atmosphere and the oxygen introduction ratio is the lowest. In addition, the cemented carbide substrate moves from the Y-Ti alloy cathode electrode closest position to the intermediate Y / Ti alloy cathode electrode closest position through the Ti-Ti alloy. The reaction atmosphere during the rotational movement to the Y alloy cathode electrode closest position is a continuously changing atmosphere in which the oxygen introduction ratio continuously decreases and the nitrogen introduction ratio continuously increases correspondingly. On the other hand, during the rotation of the cemented carbide substrate from the Ti-Y alloy cathode electrode closest position to the Y-Ti alloy cathode electrode closest position via the intermediate Ti / Y alloy cathode electrode closest position. The method of the present invention is carried out under the condition that the reaction atmosphere is a continuously changing atmosphere in which the nitrogen introduction ratio is continuously reduced and the oxygen introduction ratio is continuously increased. Along the thickness direction, Y and oxygen maximum content points and Ti and nitrogen maximum content points of the target compositions shown in Tables 3 and 4 are alternately present at target intervals also shown in Tables 3 and 4, And the content ratios of Y, oxygen and Ti and nitrogen continuously change from the Y and oxygen maximum content points to the Ti and nitrogen maximum content points, and from the Ti and nitrogen maximum content points to the Y and oxygen maximum content points, respectively. Slow-away tips made of a surface-coated cemented carbide alloy of the present invention as a coated cemented carbide tool of the present invention having a component concentration distribution structure as shown in FIG. (Hereinafter referred to as coated carbide tips of the present invention) 1 to 16 were produced.
[0017]
For the purpose of comparison, the superhard substrates A-1 to A-10 and B-1 to B-6 were ultrasonically cleaned in acetone, dried, and then dried in a normal arc shown in FIG. The apparatus was charged into an ion plating apparatus, and Ti—Y alloys having various component compositions were mounted as a cathode electrode (evaporation source). Further, metal Ti for bombarding was also mounted. After the inside of the apparatus was heated to 500 ° C. with a heater while maintaining a vacuum of 0.5 Pa or less, a DC bias voltage of −1000 V was applied to the cemented carbide substrate, and a voltage was applied between the metal Ti of the cathode electrode and the anode electrode. A current of 100 A is applied to generate arc discharge to clean the surface of the super hard substrate by Ti bombarding. Then, nitrogen gas is introduced into the apparatus as a reaction gas to make a reaction atmosphere of 2 Pa. A conventional method was carried out under the condition that a direct current bias voltage of −100 V was applied, and a current of 100 A was caused to flow between the Ti—Y alloy of the cathode electrode and the anode electrode to generate an arc discharge. -1 to A-10 and B-1 to B-6 have the target composition and target layer thickness shown in Table 5 on each surface, and there is substantially no composition change along the layer thickness direction ( Conventional surface coated cemented carbide throwaway tips (hereinafter referred to as conventional coated cemented carbide tips) 1 to 16 as conventional coated cemented carbide tools formed by vapor deposition of a hard coating layer composed of a Ti, Y) N layer, respectively. Manufactured.
[0018]
Next, the coated carbide tips 1-16 and the coated carbide tips 1-16 of the present invention obtained by the method of the present invention and the conventional method were screwed to the tip of a tool steel cutting tool with a fixing jig. In the state,
Work material: JIS SNCM439 round bar,
Cutting speed: 380 m / min. ,
Cut: 1.5 mm,
Feed: 0.2 mm / rev. ,
Cutting time: 10 minutes,
Dry continuous high-speed cutting test of alloy steel under the conditions of
Work material: Round bar with four vertical grooves at equal intervals in the longitudinal direction of JIS FC250,
Cutting speed: 400 m / min. ,
Cut: 2mm,
Feed: 0.3 mm / rev. ,
Cutting time: 5 minutes,
Intermittent high-speed cutting test of cast iron under the following conditions,
Work material: JIS S50C round bar,
Cutting speed: 350 m / min. ,
Cut: 1.5 mm,
Feed: 0.2 mm / rev. ,
Cutting time: 5 minutes,
A dry continuous high-speed cutting test of carbon steel was performed under the following conditions, and the flank wear width of the cutting edge was measured in each cutting test. Table 6 shows the measurement results.
[0019]
[Table 1]
[Table 2]
[Table 3]
[Table 4]
[Table 5]
[Table 6]
(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, and ZrC of 1.2 μm Powder, 2.3 μm Cr 3 C 2 powder, 1.5 μm VC powder, 1.0 μm (Ti, W) C [TiC / WC = 50/50 by mass ratio] powder, and 1 μm 0.8 μm Co powder was prepared, and each of these raw material powders was blended to the composition shown in Table 7, and further added with wax, and ball-mixed in acetone for 60 hours, dried under reduced pressure, and then dried under reduced pressure at 100 MPa. And press-molding these compacts to a predetermined temperature in the range of 1370 to 1470 ° C. at a rate of 7 ° C./min in a vacuum atmosphere of 6 Pa. After holding at temperature for 1 hour, sintering under furnace cooling condition Then, three types of round bar sintered bodies for forming a carbide substrate having a diameter of 8 mm, 13 mm, and 26 mm were formed. Carbide substrate having dimensions of 6 mm × 13 mm, 10 mm × 22 mm, and 20 mm × 45 mm, respectively, and a four-flute square shape with a torsion angle of 30 ° (diameter × length of the cutting edge portion is 30 mm). End mills) C-1 to C-8 were produced respectively.
[0026]
Next, the surfaces of these super-hard substrates (end mills) C-1 to C-8 were ultrasonically cleaned in acetone, dried, and charged into an arc ion plating apparatus also shown in FIG. The method of the present invention was carried out under the same conditions as in Example 1 above, and the surface of the cemented carbide substrate (end mill) was then coated along the thickness direction with the target compositions of Y and oxygen having the maximum contents shown in Table 8 and Ti. And the nitrogen maximum content point alternately and repeatedly at the target intervals also shown in Table 8, and the Ti and nitrogen maximum content point from the Y and oxygen maximum content point, and the Y and the Y content from the Ti and nitrogen maximum content point And a hard coating layer having a target layer thickness also shown in Table 8 having a component concentration distribution structure in which the contents of Y and oxygen and the contents of Ti and nitrogen continuously change to the highest oxygen content point. Become The present invention coated cemented carbide end mills 1 to 8 as an invention coated cemented carbide tools were produced.
[0027]
For the purpose of comparison, the above-mentioned ultra-hard substrates (end mills) C-1 to C-8 were ultrasonically cleaned in acetone and dried, and then a normal arc ion plating apparatus also shown in FIG. And the conventional method was carried out under the same conditions as in Example 1 above, and thus had the target composition and the target layer thickness shown in Table 9, and showed a substantial change in composition along the layer thickness direction. Conventional surface-coated cemented carbide end mills (hereinafter referred to as conventional coated cemented carbide end mills) 1 to 8 as conventional coated cemented carbide tools formed by vapor deposition of a hard coating layer made of a (Ti, Y) N layer. Manufactured.
[0028]
Next, among the coated carbide end mills 1 to 8 and the 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 coated carbide For end mills 1-3,
Work material: Plane dimensions: 100 mm x 250 mm, thickness: 50 mm JIS S50C plate,
Cutting speed: 160 m / min. ,
Axial cut: 8mm
Radial cut: 1.2mm,
Table feed: 650 mm / min,
For the wet high-speed side cutting test of carbon steel under the following conditions, the coated carbide end mills 4 to 6 and the coated carbide end mills 4 to 6 of the present invention obtained by the method of the present invention and the conventional method described above,
Workpiece: planar dimensions: 100 mm × 250 mm, thickness: 50mm of JIS · SKD61 (hardness: H R C52) plate material,
Cutting speed: 45 m / min. ,
Axial cut: 8mm
Radial cut: 0.5mm,
Table feed: 150 mm / min,
The wet-type high-speed side cutting test of tool steel under the following conditions, the coated carbide end mills 7, 8 obtained by the method of the present invention and the conventional method, and the conventional coated carbide end mills 7, 8 obtained by the conventional method are as follows:
Work material: Plane dimensions: 100 mm x 250 mm, thickness: 50 mm JIS SCM440 plate,
Cutting speed: 60 m / min. ,
Axial cut: 24 mm,
Radial cut: 4mm,
Table feed: 350 mm / min.
Wet high-speed side cutting tests of alloy steels under the conditions described above were performed, and in any wet side cutting test (using water-soluble cutting oil), the flank wear width of the outer peripheral edge of the cutting edge is used as a guide for the service life. The cutting length up to 0.1 mm was measured. The measurement results are shown in Tables 8 and 9, respectively.
[0029]
[Table 7]
[Table 8]
[Table 9]
(Example 3)
The diameters produced in Example 2 were 8 mm (for forming the super-hard substrates C-1 to C-3), 13 mm (for forming the super-hard substrates C-4 to C-6), and 26 mm (for the super-hard substrates C-). 7, for forming C-8), the diameter x length of the groove forming portion was 4 mm x 13 mm (by grinding) from the three types of round rod sintered bodies by grinding. Carbide substrates D-1 to D-3), dimensions of 8 mm x 22 mm (carbide substrates D-4 to D-6), and 16 mm x 45 mm (carbide substrates D-7 and D-8), and any of them Carbide substrates (drills) D-1 to D-8 each having a two-blade shape with a twist angle of 30 degrees were manufactured.
[0033]
Next, the cutting edges of these superhard substrates (drills) D-1 to D-8 are honed, ultrasonically cleaned in acetone, and dried, and then the arc ion plating apparatus shown in FIG. , And the method of the present invention was carried out under the same conditions as in Example 1 described above. Then, Y and oxygen having the target compositions shown in Table 10 were placed on the surface of the cemented carbide (drill) along the thickness direction. The highest content point and the highest Ti and nitrogen content points are alternately repeated at the same target intervals as shown in Table 10, and the highest Y and oxygen content points are the highest Ti and nitrogen content points, and the highest Ti and nitrogen content points. A hard coating layer having a component concentration distribution structure in which the content ratios of Y, oxygen and Ti and nitrogen continuously change from the point to the Y and oxygen maximum content points, respectively, and also having the target layer thickness shown in Table 10 Steaming Forming the present invention coated cemented carbide drills 1-8 respectively as the present invention coated cemented carbide comprising manufactured.
[0034]
Also, 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, and are also shown in FIG. The conventional method was loaded into a normal arc ion plating apparatus, and the conventional method was carried out under the same conditions as in Example 1 above, and thus had the target composition and the target layer thickness shown in Table 11, and along the layer thickness direction. And a conventional coated cemented carbide drill (hereinafter referred to as a conventional coated cemented carbide drill) as a conventionally coated cemented carbide tool formed by depositing a hard coating layer composed of a (Ti, Y) N layer having substantially no composition change. 1 to 8 were manufactured respectively.
[0035]
Next, among the coated carbide drills 1 to 8 of the present invention 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 of the present invention and the conventionally coated carbide For drills 1-3,
Work material: Plane dimensions: 100 mm × 250, thickness: 50 mm, JIS SNCM439 plate material,
Cutting speed: 200 m / min. ,
Feed: 0.15 mm / rev,
Hole depth: 8mm,
For the wet-type high-speed drilling test of the alloy steel under the conditions of the present invention, the coated carbide drills 4 to 6 and the coated carbide drills 4 to 6 of the present invention obtained by the above-described method of the present invention and the conventional method,
Work material: Plane dimensions: 100 mm x 250 mm, thickness: 50 mm, JIS S55C plate,
Cutting speed: 120 m / min. ,
Feed: 0.25 mm / rev,
Hole depth: 16mm,
The wet-type high-speed drilling test of carbon steel under the following conditions, the coated carbide drills 7 and 8 of the present invention obtained by the method of the present invention and the conventional method, and the conventional coated carbide drills 7 and 8 of the present invention are:
Workpiece: planar dimensions: 100 mm × 250 mm, thickness: 50mm of JIS · SKD61 (hardness: H R C52) plate material,
Cutting speed: 20 m / min. ,
Feed: 0.18 mm / rev,
Hole depth: 24mm,
Welding high-speed drilling cutting test of tool steel was conducted under the conditions described above, and in all wet high-speed high-feed drilling cutting tests (using water-soluble cutting oil), the flank wear width of the tip cutting edge surface was reduced to 0.3 mm. The number of drilling operations up to that point was measured. The measurement results are shown in Tables 10 and 11, respectively.
[0036]
[Table 10]
[Table 11]
The coated carbide tips 1-16, coated carbide end mills 1-8, coated carbide drills 1-8 of the present invention as coated carbide tools of the present invention obtained by the above-described method of the present invention, and conventional The thickness direction of the hard coating layers constituting the conventional coated carbide tips 1-16, the conventional coated carbide end mills 1-8, and the conventional coated carbide drills 1-8 as conventional coated carbide tools obtained by the method The content ratios of Y, Ti, oxygen, and nitrogen were measured using an Auger spectrometer along with the hard coating layer of the coated carbide tool of the present invention. Are present alternately and repeatedly at substantially the same composition and interval as the target value, respectively, and from the maximum content point of Y and oxygen to the maximum content point of Ti and nitrogen, and the maximum content of Ti and nitrogen. From the results, it has been confirmed that the content ratio of Y and oxygen and the content ratio of Ti and nitrogen continuously change to the highest content points of Y and oxygen, respectively, and that the average thickness of the hard coating layer is also the target layer thickness. And showed substantially the same value. On the other hand, in the hard coating layer of the conventional coated carbide tool, although the composition is substantially the same as the target composition and the overall average layer thickness is substantially the same as the target layer thickness, the composition change along the thickness direction is observed. And 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, in the layer thickness direction, the highest content points of Y and oxygen, which have relatively higher high-temperature hardness and heat resistance. The highest content points of Ti and nitrogen having excellent high-temperature strength are alternately and repeatedly present at predetermined intervals, and the highest content points of Ti and nitrogen, the highest content points of Ti and nitrogen, A coated carbide comprising a Y-Ti oxynitride layer having a component concentration distribution structure in which the contents of Y and oxygen and the contents of Ti and nitrogen continuously change from the highest nitrogen content point to the highest Y and oxygen content points, respectively. All the tools show excellent wear resistance even when cutting is performed under high-speed conditions with particularly high heat generation, and exhibit excellent cutting performance over a long period of time. Obtained by In the case of a conventional coated cemented carbide tool in which the hard coating layer comprises a (Ti, Y) N layer having substantially no composition change along the layer thickness direction, the high-temperature hardness of the hard coating layer under the high-speed cutting conditions described above. In addition, since the wear progress of the hard coating layer is further promoted due to the lack of heat resistance, it is apparent that the service life can be reached in a relatively short time.
As described above, according to the method of the present invention, not only cutting under ordinary conditions such as various kinds of steel and cast iron, but also particularly under high-speed cutting conditions with high heat generation, a long-term operation is possible. It is possible to manufacture coated carbide tools that exhibit excellent wear resistance, and thus the resulting coated carbide tools can sufficiently satisfy cutting power savings, energy savings, and cost reductions. You can do it.
[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 conventional arc ion plating apparatus used for forming a hard coating layer constituting a conventional coated carbide tool.
Claims (2)
さらに、上記Ｙおよび酸素の最高含有点が、
組成式：（Ｙ１− ＡＴｉＡ）Ｏ１−ＤＮＤ（ただし、原子比で、Ａは０．０５〜０．３０、Ｄは０．０２〜０．１０を示す）、
上記Ｔｉおよび窒素の最高含有点が、
組成式：（Ｔｉ１− ＢＹＢ）Ｎ１−ＥＯＥ（ただし、原子比で、Ｂは０．４０〜０．６５、Ｅは０．０２〜０．１０を示す）、
を満足し、かつ隣り合う上記Ｙ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、
硬質被覆層で構成した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。A hard coating layer composed of a composite oxynitride layer of Y (yttrium) and Ti is physically vapor-deposited on the surface of a cemented carbide substrate composed of a tungsten carbide-based cemented carbide or a titanium carbonitride-based cermet with an average layer thickness of 1 to 15 μm. The surface-coated cemented carbide cutting tool has a maximum content of Y and oxygen and a maximum content of Ti and nitrogen alternately at predetermined intervals along the thickness of the hard coating layer. And from the maximum content of Y and oxygen to the maximum content of Ti and nitrogen, from the maximum content of Ti and nitrogen to the maximum content of Y and oxygen, the content ratio of Y and oxygen and Ti and nitrogen is Each having a continuously varying component concentration distribution structure,
Further, the maximum content point of Y and oxygen is
Composition formula: (Y 1 -A Ti A ) O 1 -D N D (however, A represents 0.05 to 0.30 and D represents 0.02 to 0.10 in atomic ratio),
The maximum content of Ti and nitrogen is
Formula: (Ti 1- B Y B) N 1-E O E ( However, in atomic ratio, B is .40-0.65, E represents a 0.02 to 0.10),
And the interval between the adjacent highest content points of Y and oxygen and the highest content points of Ti and nitrogen is 0.01 to 0.1 μm,
A cutting tool made of a surface-coated cemented carbide in which the hard coating layer exhibits excellent wear resistance under high-speed cutting conditions characterized by comprising a hard coating layer.
（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Ｙ含有割合の高いＹ−Ｔｉ合金と、相対的にＴｉ含有割合の高いＴｉ−Ｙ合金を対向配置すると共に、それぞれ前記Ｙ−Ｔｉ合金に比してＹ含有割合が低く、かつ前記Ｔｉ−Ｙ合金に比してＴｉ含有割合が低い中間Ｙ／Ｔｉ合金および中間Ｔｉ／Ｙ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Ｙ含有量の高いＹ−Ｔｉ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−Ｙ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Ｙ−Ｔｉ合金のカソード電極最接近位置から上記中間Ｙ／Ｔｉ合金のカソード電極最接近位置を経て前記Ｔｉ−Ｙ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−Ｙ合金のカソード電極最接近位置から上記中間Ｔｉ／Ｙ合金のカソード電極最接近位置を経て前記Ｙ−Ｔｉ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、Ｙ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Ｙ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Ｙおよび酸素の最高含有点へＹ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ＹとＴｉ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) On a rotary table in an arc ion plating apparatus, a tungsten carbide-based cemented carbide substrate and / or a titanium carbonitride-based cermet eccentrically eccentric to a position radially away from the center axis of the rotary table. Attach the carbide substrate to rotate freely,
(B) In addition, a Y-Ti alloy having a relatively high Y content and a Ti-Y alloy having a relatively high Ti content are opposed to each other as a cathode electrode (evaporation source) across the rotary table. And an intermediate Y / Ti alloy and an intermediate Ti / Y alloy each having a lower Y content ratio than the Y-Ti alloy and a lower Ti content ratio than the Ti-Y alloy. And
(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 at the time when the cemented carbide substrate is closest to the cathode electrode of the Y-Ti alloy having a relatively high Y content is the reaction atmosphere having the highest oxygen introduction ratio and the lowest nitrogen introduction ratio. On the other hand, when the cemented carbide substrate comes closest to the above-mentioned Ti—Y alloy cathode electrode having a relatively high Ti content, the reaction atmosphere has the highest nitrogen introduction rate and the lowest oxygen introduction rate. In addition to the atmosphere, the cemented carbide substrate moves from the Y-Ti alloy cathode electrode closest position to the intermediate Y / Ti alloy cathode electrode closest position, and then the Ti-Y alloy cathode electrode closest position. The reaction atmosphere during the rotational movement is a continuously changing atmosphere in which the oxygen introduction ratio is continuously reduced and the nitrogen introduction ratio is continuously increased correspondingly, while the carbide substrate is made of the Ti-Y alloy. The reaction atmosphere during the rotational movement from the cathode electrode closest position to the Y-Ti alloy cathode electrode closest position through the intermediate Ti / Y alloy cathode electrode closest position is continuously reduced in the nitrogen introduction ratio. Corresponding to this, a continuously changing atmosphere in which the oxygen introduction ratio continuously increases,
(E) On the surface of the cemented carbide substrate which eccentrically rotates while rotating on the rotary table, the maximum content point of Y and oxygen and the maximum content point of Ti and nitrogen are arranged at predetermined intervals along the layer thickness direction. And from the highest content of Y and oxygen to the highest content of Ti and nitrogen, from the highest content of Ti and nitrogen to the highest content of Y and oxygen, and Y and oxygen and Physical vapor deposition of a hard coating layer composed of a composite oxynitride layer of Y and Ti having a component concentration distribution structure in which the content ratios of Ti and nitrogen are respectively continuously changed,
A method for producing a surface-coated cemented carbide cutting tool in which a hard coating layer exhibits excellent wear resistance under high-speed cutting conditions characterized by the above (a) to (e).
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| JP2003142068A Expired - Fee Related JP4150916B2 (en) | 2003-05-20 | 2003-05-20 | 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 |
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| Country | Link |
|---|---|
| JP (1) | JP4150916B2 (en) |
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| Publication number | Publication date |
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| JP4150916B2 (en) | 2008-09-17 |
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