JP4193110B2 - A method of forming a hard coating layer on the cutting tool surface that exhibits excellent wear resistance under high-speed cutting conditions - Google Patents
A method of forming a hard coating layer on the cutting tool surface that exhibits excellent wear resistance under high-speed cutting conditions Download PDFInfo
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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、すぐれた耐摩耗性を発揮する硬質被覆層を切削工具表面に形成する方法に関するものである。
【０００２】
【従来の技術】
一般に、切削工具には、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、切削工具として、例えば図２に概略縦断面図で示される通り、中央部にステンレス鋼製の反応ガス吹き出し管が立設され、前記反応ガス吹き出し管には、黒鉛製の切削工具支持パレットが串刺し積層嵌着され、かつこれらがステンレス鋼製のカバーを介してヒーターで加熱される構造を有する化学蒸着装置を用い、炭化タングステン（以下、ＷＣで示す）基超硬合金または炭窒化チタン（以下、ＴｉＣＮで示す）基サーメットからなる切削工具を前記切削工具支持パレットの底面に形成された多数の反応ガス通過穴位置に載置した状態で前記化学蒸着装置に装入し、ヒータで装置内を、例えば８００〜１１００℃の範囲内の所定の温度に加熱した後、酸化アルミニウム（以下、Ａｌ2Ｏ3で示す）層形成には、反応ガスとして、容量％で（以下、反応ガスの％は容量％を示す）、
ＡｌＣｌ3：２〜７％、
ＣＯ2：２〜１０％、
ＨＣｌ：３〜７％、
Ｈ2：残り、
からなる組成を有する反応ガスを用い、また、窒化チタン（以下、ＴｉＮで示す）層形成には、
ＴｉＣｌ4：１〜３％、
Ｎ2：４０〜６０％、
Ｈ2：残り、
からなる組成を有する反応ガスを用い、これらの反応ガスを予め真空排気された装置内に前記反応ガス吹き出し管を通して、装置内の反応ガス圧力を７〜４０ｋＰａの範囲内の所定の圧力に保持しながら、交互に導入することにより個々の層厚が１μm以下のＡｌ2Ｏ3層とＴｉＮ層とを交互積層して、１〜１５μｍの全体平均層厚で蒸着してなる被覆切削工具が提案され、前記硬質被覆層を構成するＡｌ2Ｏ3−ＴｉＮ交互積層が、Ａｌ2Ｏ3層による高温硬さおよび耐熱性と、ＴｉＮ層による強度を具備することから、かかる被覆切削工具を各種の鋼や鋳鉄などの連続切削や断続切削加工に用いた場合にすぐれた切削性能を発揮することも知られている（例えば、特許文献１参照）。
【０００４】
【特許文献１】
特開昭５２−１０５３９６号公報
【０００５】
【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、上記の従来被覆切削工具においては、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、Ａｌ2Ｏ3−ＴｉＮ交互積層からなる硬質被覆層のＡｌ2Ｏ3層はすぐれた高温硬さと耐熱性を有するものの高温強度の低いものであり、また同じくＴｉＮ層は前記Ａｌ2Ｏ3層に比して相対的に高い高温強度を有するが、十分満足するものではなく、さらに相対的に高温硬さおよび耐熱性の低いものであることから、きわめて高い発熱を伴なう前記難削材の高速切削では、前記硬質被覆層の高温強度不足が原因で、切刃稜線部に熱塑性変形が発生し、この結果摩耗進行が急速に促進されるようになるので、比較的短時間で使用寿命に至るのが現状である。
【０００６】
【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、特に被覆切削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切削工具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含有量の高いＡｌ−Ｔｉ合金、他方側に相対的にＴｉ含有量の高いＴｉ−Ａｌ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合金に比してＡｌ含有量が低く、かつ前記Ｔｉ−Ａｌ合金に比してＴｉ含有量が低い中間Ａｌ／Ｔｉ合金と中間Ｔｉ／Ａｌ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切削工具を装着し、
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切削工具の回転移動位置に対応して調整して、前記切削工具が上記の相対的にＡｌ含有量の高いＡｌ−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、前記切削工具が上記の相対的にＴｉ含有量の高いＴｉ−Ａｌ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、前記切削工具が前記Ａｌ−Ｔｉ合金のカソード電極最接近位置から上記中間Ａｌ／Ｔｉ合金のカソード電極最接近位置を経て前記Ｔｉ−Ａｌ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、一方前記切削工具が前記Ｔｉ−Ａｌ合金のカソード電極最接近位置から上記中間Ｔｉ／Ａｌ合金のカソード電極最接近位置を経て前記Ａｌ−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切削工具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、
上記の従来被覆切削工具の硬質被覆層の構成成分であるＡｌ2Ｏ3とＴｉＮの複合化合物、すなわちＡｌとＴｉの複合酸窒化物（以下、Ａｌ−Ｔｉ酸窒化物という）層を形成すると、
上記切削工具の表面には、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切削工具が上記の一方側の相対的にＡｌ含有量の高いＡｌ−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Ａｌおよび酸素の最高含有点が形成され、また前記前記切削工具が上記の他方側の相対的にＴｉ含有量の高いＴｉ−Ａｌ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と窒素の含有量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。
【０００７】
（ｂ）上記（ａ）の繰り返し連続変化成分濃度分布構造のＡｌ−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、切削工具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：（Ａｌ1-XＴｉX）Ｏ1-YＮY（ただし、原子比で、Ｘは０．０５〜０．３０、Ｙは０．０２〜０．１０）、
上記Ｔｉおよび窒素の最高含有点が、
組成式：（Ｔｉ1-VＡｌV）Ｎ1-WＯW（ただし、原子比で、Ｖは０．３５〜０．６５、Ｗ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、Ａｌの高含有で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と窒素の含有量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、例えば上記の従来被覆切削工具であれば、Ａｌ2Ｏ3層とＴｉＮ層間の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酸窒化物層を硬質被覆層として形成してなる被覆切削工具は、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。
【０００８】
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、
（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ＷＣ基超硬合金および／またはＴｉＣＮ系サーメットからなる切削工具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含有量の高いＡｌ−Ｔｉ合金と、相対的にＴｉ含有量の高いＴｉ−Ａｌ合金を対向配置すると共に、それぞれ前記Ａｌ−Ｔｉ合金に比してＡｌ含有量が低く、かつ前記Ｔｉ−Ａｌ合金に比してＴｉ含有量が低い中間Ａｌ／Ｔｉ合金と中間Ｔｉ／Ａｌ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切削工具の回転移動位置に対応して調整して、前記切削工具が上記の相対的にＡｌ含有量の高いＡｌ−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、前記切削工具が上記の相対的にＴｉ含有量の高いＴｉ−Ａｌ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、前記切削工具が前記Ａｌ−Ｔｉ合金のカソード電極最接近位置から上記中間Ａｌ／Ｔｉ合金のカソード電極最接近位置を経て前記Ｔｉ−Ａｌ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、一方前記切削工具が前記Ｔｉ−Ａｌ合金のカソード電極最接近位置から上記中間Ｔｉ／Ａｌ合金のカソード電極最接近位置を経て前記Ａｌ−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切削工具の表面に、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と窒素の含有量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：（Ａｌ1-XＴｉX）Ｏ1-YＮY（ただし、原子比で、Ｘは０．０５〜０．３０、Ｙは０．０２〜０．１０）、
上記Ｔｉおよび窒素の最高含有点が、
組成式：（Ｔｉ1-VＡｌV）Ｎ1-WＯW（ただし、原子比で、Ｖは０．３５〜０．６５、Ｗ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、
Ａｌ−Ｔｉ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、
高速切削条件ですぐれた耐摩耗性を発揮する硬質被覆層を切削工具表面に形成する方法に特徴を有するものである。
【０００９】
つぎに、この発明の硬質被覆層形成方法において、形成される硬質被覆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酸窒化物層において、Ａｌおよび酸素の最高含有点部分で高含有のＡｌと酸素の作用ですぐれた高温硬さと耐熱性を示し、一方Ｔｉおよび窒素の最高含有点部分では高含有のＡｌのＴｉおよび窒素と共存した状態での作用ですぐれた高温強度を示すものであり、したがってＡｌおよび酸素の最高含有点では、ＴｉのＡｌとの合量に占める含有割合を示すＸ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Ｙ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０．３０を越えたり、同Ｙ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Ｘ値を０．０５〜０．３０、窒素の含有割合を示すＹ値を０．０２〜０．１０と定めた。
【００１０】
（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、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との合量に占める含有割合を示すＶ値が０．３５未満でも、また同Ｖ値が０．６５を越えても、所望のすぐれた高温強度を確保することができず、一方酸素の窒素との合量に占める含有割合を示すＷ値が０．０２未満になると、Ｔｉおよび窒素の最高含有点に所定の高温硬さおよび耐熱性を確保することができず、これが摩耗促進の原因となり、また同Ｗ値が０．１０を越えると、高温強度が急激に低下するようになることから、Ａｌの含有割合を示すＶ値を０．３５〜０．６５、酸素の含有割合を示すＷ値を０．０２〜０．１０と定めた。
【００１１】
（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。
【００１２】
（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。
【００１３】
【発明の実施の形態】
つぎに、この発明の硬質被覆層形成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、切削工具としてＩＳＯ規格・ＣＮＭＧ１２０４１２の形状をもったＷＣ基超硬合金製のスローアウエイチップ（以下、チップ工具という）Ａ−１〜Ａ−１０を形成した。
【００１４】
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、切削工具としてＩＳＯ規格・ＣＮＭＧ１２０４１２の形状をもったＴｉＣＮ系サーメット製のチップ工具Ｂ−１〜Ｂ−６を形成した。
【００１５】
ついで、上記のチップ工具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合金に比してＡｌ含有量が低く、かつ前記Ｔｉ−Ａｌ合金に比してＴｉ含有量が低い中間Ａｌ／Ｔｉ合金と中間Ｔｉ／Ａｌ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チップ工具に−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、もってチップ工具表面を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チップ工具に−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合金、前記Ｔｉおよび窒素最高含有点形成用Ｔｉ−Ａｌ合金、さらに前記中間Ａｌ／Ｔｉ合金および中間Ｔｉ／Ａｌ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、前記切削工具が上記の相対的にＡｌ含有量の高いＡｌ−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、前記切削工具が上記の相対的にＴｉ含有量の高いＴｉ−Ａｌ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、前記切削工具が前記Ａｌ−Ｔｉ合金のカソード電極最接近位置から上記中間Ａｌ／Ｔｉ合金のカソード電極最接近位置を経て前記Ｔｉ−Ａｌ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、一方前記切削工具が前記Ｔｉ−Ａｌ合金のカソード電極最接近位置から上記中間Ｔｉ／Ａｌ合金のカソード電極最接近位置を経て前記Ａｌ−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１〜１６を実施し、もって前記チップ工具の表面に、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と窒素の含有量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切削工具としての本発明被覆チップ工具を製造した。
【００１６】
また、比較の目的で、これらチップ工具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、図２に示される化学蒸着装置に装入し、Ａｌ2Ｏ3層の形成条件を、
反応ガス組成：（容量％で）ＡｌＣｌ3：３％、ＣＯ2：７％、ＨＣｌ：３％、Ｈ2：残り、
反応雰囲気温度：１０００℃、
反応雰囲気圧力：７ｋＰａ、
とし、また、ＴｉＮ層の形成条件を、
反応ガス組成：（容量％で）ＴｉＣｌ4：２％、Ｎ2：５５％、Ｈ2：残り、
反応雰囲気温度：１０００℃、
反応雰囲気圧力：１３ｋＰａ、
として、それぞれ表５，６に示される目標層厚のＡｌ2Ｏ3層およびＴｉＮ層の交互積層からなる硬質被覆層を、前記チップ工具Ａ１〜Ａ１０およびＢ１〜Ｂ６のそれぞれの表面に、同じく表５，６に示される目標全体層厚で蒸着形成する従来法１〜１６をそれぞれ実施し、従来被覆切削工具としての従来被覆チップ工具を製造した。
【００１７】
つぎに、上記本発明法１〜１６および従来法１〜１６により得られた被覆チップ工具をいずれも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、上記本発明法１〜１０および従来法１〜１０により得られた被覆チップ工具については、
被削材：ＪＩＳ・ＳＵＳ３１６の丸棒、
切削速度：２５０ｍ／ｍｉｎ．、
切り込み：１．５ｍｍ、
送り：０．２５ｍｍ／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なった。
【００１８】
また、上記本発明法１１〜１６および従来法１１〜１６により得られた被覆チップ工具については、
被削材：ＪＩＳ・ＳＵＳ３０４の丸棒、
切削速度：２５０ｍ／ｍｉｎ．、
切り込み：１．５ｍｍ、
送り：０．７５ｍｍ／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・ＳＵＳ３１６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：０．２ｍｍ／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：３００ｍ／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】
【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種のエンドミル工具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エンドミル工具Ｃ−１〜Ｃ−８を切削工具としてそれぞれ製造した。
【００２６】
ついで、これらのエンドミル工具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１７〜２４を実施し、もって前記チップ工具の表面に、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と窒素の含有量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切削工具としての本発明被覆エンドミル工具を製造した。
【００２７】
また、比較の目的で、上記のエンドミル工具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２に示される化学蒸着装置に装入し、上記実施例１における硬質被覆層の形成条件と同一の条件で従来法１７〜２４を実施し、もって表９に示される目標層厚のＡｌ2Ｏ3層およびＴｉＮ層の交互積層からなる硬質被覆層を、前記エンドミル工具Ｃ−１〜Ｃ−８のそれぞれの表面に、同じく表９に示される目標全体層厚で蒸着形成してなる従来被覆切削工具としての従来被覆エンドミル工具を製造した。
【００２８】
つぎに、上記本発明法１７〜２４および従来法１７〜２４により得られた被覆エンドミル工具ついて、これらのうち本発明法１７〜１９および従来法１７〜１９により得られた被覆エンドミル工具については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＳＵＳ３０４の板材、
切削速度：１４０ｍ／ｍｉｎ．、
軸方向切り込み：９ｍｍ、
径方向切り込み：０．６ｍｍ、
テーブル送り：６００ｍｍ／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、本発明法２０〜２２および従来法２０〜２２により得られた被覆エンドミル工具については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・Ｓ１５Ｃの板材、
切削速度：２００ｍ／ｍｉｎ．、
軸方向切り込み：１５ｍｍ、
径方向切り込み：２ｍｍ、
テーブル送り：１０００ｍｍ／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２３．２４および従来法２３．２４により得られた被覆エンドミル工具については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＳＵＳ３１６の板材、
切削速度：１２０ｍ／ｍｉｎ．、
軸方向切り込み：３０ｍｍ、
径方向切り込み：４ｍｍ、
テーブル送り：７５０ｍｍ／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】
【表８】
【表９】
（実施例３）
上記の実施例２で製造した直径が８ｍｍ（エンドミル工具Ｃ−１〜Ｃ−３形成用）、１３ｍｍ（エンドミル工具Ｃ−４〜Ｃ−６形成用）、および２６ｍｍ（エンドミル工具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（ドリル工具Ｄ−１〜Ｄ−３）、８ｍｍ×２２ｍｍ（ドリル工具Ｄ−４〜Ｄ−６）、および１６ｍｍ×４５ｍｍ（ドリル工具Ｄ−７、Ｄ−８）の寸法、並びにいずれもねじれ角：３０度の２枚刃形状をもったドリル工具Ｄ−１〜Ｄ−８を切削工具としてそれぞれ製造した。
【００３３】
ついで、これらのドリル工具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２５〜３２を実施し、もって前記ドリル工具の表面に、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と窒素の含有量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切削工具としての本発明被覆ドリル工具を製造した。
【００３４】
また、比較の目的で、上記のドリル工具Ｄ−１〜Ｄ−８の表面に、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に示される化学蒸着装置に装入し、上記実施例１における硬質被覆層の形成条件と同一の条件で従来法２５〜３２を実施し、もって表１１に示される目標層厚のＡｌ2Ｏ3層およびＴｉＮ層の交互積層からなる硬質被覆層を、前記ドリル工具Ｄ−１〜Ｄ−８のそれぞれの表面に、同じく表１１に示される目標全体層厚で蒸着形成してなる従来被覆切削工具としての従来被覆ドリル工具を製造した。
【００３５】
つぎに、上記本発明法２５〜３２および従来法２５〜３２により得られた被覆ドリル工具について、これらのうち本発明法２５〜２７および従来法２５〜２７により得られた被覆ドリル工具については、
被削材：平面寸法：１００ｍｍ×２５０、厚さ：５０ｍｍのＪＩＳ・Ｓ１５Ｃ
の板材、
切削速度：１６０ｍ／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、本発明法２８〜３０および従来法２８〜３０により得られた被覆ドリル工具については、
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３１，３２および従来法３１，３２により得られた被覆ドリル工具については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・Ｓ１５Ｃの板材、
切削速度：１２０ｍ／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】
【表１１】
なお、上記本発明法１〜３２および従来法１〜３２で得られた各種の被覆切削工具の硬質被覆層について、厚さ方向に沿ってＡｌ、Ｔｉ、酸素、および窒素の含有量をオージェ分光分析装置を用いて測定したところ、本発明法１〜３２で形成された硬質被覆層では、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Ａｌおよび酸素の最高含有点から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量が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、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。また、上記従来法１〜３２で得られた各種の被覆切削工具の硬質被覆層においても目標層厚と実質的に同じ平均層厚のＡｌ2Ｏ3層とＴｉＮ層とが交互に、かつ目標全体層厚と実質的に同じ平均層厚で形成されていることが確認された。
【００３９】
【発明の効果】
表３〜１１に示される結果から、上記本発明法１〜３２にて、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量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酸窒化物層からなる硬質被覆層を形成してなる被覆切削工具は、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１〜３２にて、Ａｌ2Ｏ3層とＴｉＮ層の交互積層からなる硬質被覆層を形成してなる被覆切削工具は、いずれも前記硬質被覆層の高温強度不足が原因で、切刃稜線部に熱塑性変形が発生し、この結果摩耗形態が著しい偏摩耗となることから、摩耗進行が著しく促進されるようになり、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、この発明の硬質被覆層形成方法によれば、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硬質被覆層を切削工具表面に形成することができ、この結果の被覆切削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できるものとなるのである。
【図面の簡単な説明】
【図１】本発明硬質被覆層形成方法の実施装置である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】従来硬質被覆層形成方法の実施装置である化学蒸着装置を示す概略縦断面図である。[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 method for forming a hard coating layer exhibiting excellent wear resistance on the surface of a cutting tool when carried out under high-speed machining conditions involving.
[0002]
[Prior art]
In general, for cutting tools, a throw-away tip that is used by attaching to the tip of a cutting tool for turning and planing of various steels and cast irons, drilling of the work material, etc. Drills and miniature drills, and solid type end mills used for chamfering, grooving and shouldering of the work material, etc. A slow-away end mill tool that performs cutting work in the same manner as an end mill is known.
[0003]
Further, as a cutting tool, for example, as shown in a schematic longitudinal sectional view in FIG. 2, a reaction gas blowing pipe made of stainless steel is erected in the center portion, and the reaction gas blowing pipe includes a cutting tool support pallet made of graphite. Using a chemical vapor deposition apparatus having a structure in which they are skewered and laminated, and these are heated by a heater through a stainless steel cover, tungsten carbide (hereinafter referred to as WC) based cemented carbide or titanium carbonitride ( A cutting tool composed of a base cermet (hereinafter referred to as TiCN) is placed in the chemical vapor deposition apparatus in a state where it is placed at a number of reaction gas passage hole positions formed on the bottom surface of the cutting tool support pallet, and the heater uses the heater , eg after heating to a predetermined temperature in the range of 800 to 1100 ° C., aluminum oxide (hereinafter, Al 2 O indicated by 3) the layer forming, as a reaction gas, volume% (Hereinafter,% of the reaction gas are capacitors%),
AlCl 3 : 2 to 7%,
CO 2 : 2 to 10%
HCl: 3-7%
H 2 : Remaining
For forming a titanium nitride (hereinafter referred to as TiN) layer, a reaction gas having a composition consisting of:
TiCl 4: 1~3%,
N 2 : 40-60%
H 2 : Remaining
The reaction gas pressure in the apparatus is maintained at a predetermined pressure within a range of 7 to 40 kPa through the reaction gas blowing pipe into the apparatus that has been evacuated in advance. However, a coated cutting tool is proposed in which Al 2 O 3 layers and TiN layers each having a thickness of 1 μm or less are alternately laminated by being alternately introduced, and vapor-deposited with an overall average layer thickness of 1 to 15 μm. Since the Al 2 O 3 —TiN alternating lamination layer constituting the hard coating layer has high-temperature hardness and heat resistance due to the Al 2 O 3 layer and strength due to the TiN layer, the coated cutting tool is used as various steels. It is also known to exhibit excellent cutting performance when used for continuous cutting and intermittent cutting of cast iron and cast iron (for example, see Patent Document 1).
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 52-105396
[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-described conventional coated cutting tool, for example, when it is used to cut difficult-to-cut materials such as various types of high-viscosity stainless steel and mild steel under high-speed conditions with particularly high heat generation, Al The Al 2 O 3 layer of the hard coating layer composed of 2 O 3 —TiN alternating layers has excellent high temperature hardness and heat resistance, but has a low high temperature strength. Similarly, the TiN layer is compared with the Al 2 O 3 layer. Although it has a relatively high high-temperature strength, it is not fully satisfactory, and since it has a relatively low high-temperature hardness and heat resistance, the high-speed of the difficult-to-cut material with extremely high heat generation In cutting, due to the lack of high-temperature strength of the hard coating layer, a thermoplastic deformation occurs at the edge of the cutting edge, and as a result, the progress of wear is rapidly promoted, so that the service life is reached in a relatively short time. is the current situation.
[0006]
[Means for Solving the Problems]
Therefore, the present inventors pay particular attention to the hard coating layer of the coated cutting tool from the above viewpoint, and the cutting edge ridge line portion by high-speed cutting of difficult-to-cut materials such as various highly viscous stainless steels and mild steels. As a result of conducting research to develop a hard coating layer that exhibits excellent wear resistance without the occurrence of thermoplastic deformation,
(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 cathode electrode (evaporation source) is provided with an Al—Ti alloy having a relatively high Al content on one side and a Ti—Al alloy having a relatively high Ti content on the other side across the rotary table. Further, the intermediate Al / Ti alloy and the intermediate Ti / Al alloy are low in the Al content as compared with the Al-Ti alloy and low in the Ti content as compared with the Ti-Al alloy. Similarly, an arc ion plating device arranged oppositely as a cathode electrode (evaporation source) is used.
On the rotary table of this apparatus, the cutting tool is mounted eccentrically at a position away from the central axis of the rotary table in the radial direction,
In this state, the reaction atmosphere in the 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 cutting tool, and the cutting tool The reaction atmosphere at the time when the Al-Ti alloy cathode electrode having the relatively high Al content is the closest to the cathode electrode has the highest oxygen introduction ratio and the lowest nitrogen introduction ratio. While the reaction atmosphere is 90 to 97% by volume and the rest is nitrogen, the reaction atmosphere when the cutting tool is closest to the cathode electrode of the Ti-Al alloy having the relatively high Ti content is nitrogen. The introduction ratio is the highest, the oxygen introduction ratio is the lowest, preferably the relative introduction ratio of nitrogen is 90 to 97% by volume, and the rest is oxygen, and the cutting tool is the Al-Ti The reaction atmosphere during the rotational movement from the gold cathode electrode closest position to the Ti-Al alloy cathode electrode closest position through the intermediate Al / Ti alloy cathode electrode closest position, the oxygen introduction ratio continuously And a continuous change atmosphere in which the introduction ratio of nitrogen is continuously increased correspondingly, while the cutting tool moves from the position closest to the cathode electrode of the Ti-Al alloy to the cathode electrode of the intermediate Ti / Al alloy. The reaction atmosphere during the rotational movement of the Al-Ti alloy to the cathode electrode closest position via the closest position is continuously reduced, and the oxygen introduction ratio is continuously reduced correspondingly. A continuously changing atmosphere to increase,
While rotating the rotary table and rotating the cutting tool itself for the purpose of uniforming the thickness of the hard coating layer formed by vapor deposition, an arc is formed between each cathode electrode (evaporation source) and the anode electrode. Under conditions that generate discharge,
When forming a composite compound of Al 2 O 3 and TiN that is a constituent component of the hard coating layer of the conventional coated cutting tool, that is, a composite oxynitride of Al and Ti (hereinafter referred to as Al-Ti oxynitride) layer,
On the surface of the cutting tool, the cutting tool arranged eccentrically at a position radially away from the central axis on the rotary table has a relatively high Al-Ti alloy cathode on one side. When the closest point to the electrode (evaporation source) is reached, the highest content point of Al and oxygen is formed in the layer, and the cutting tool is a cathode of Ti-Al alloy having a relatively high Ti content on the other side. Since the highest content point of Ti and nitrogen is formed in the layer when it is closest to the electrode, the highest content point of Al and oxygen in the layer along the thickness direction and Ti are formed in the layer by the rotation of the rotary table. And the highest content point of nitrogen and nitrogen alternately appear at predetermined intervals, and the highest content point of Ti and nitrogen from the highest content point of Al and oxygen, and the highest content point of Ti and nitrogen. A hard coating layer composed of an Al-Ti oxynitride layer having a component concentration distribution structure in which the contents of Al, oxygen, and Ti and nitrogen continuously change to the highest content point of Al and oxygen is formed. To become a.
[0007]
(B) When forming the Al—Ti oxynitride layer having the repeated continuous change component concentration distribution structure of (a) above, for example, the composition of each of the cathode electrodes (evaporation sources) arranged opposite to each other, and the reaction continuously changing in the apparatus While adjusting the composition of the atmosphere, that is, the mutual introduction ratio of oxygen and nitrogen, and controlling the rotational speed of the rotary table on which the cutting tool is mounted,
The maximum content point of Al and oxygen is
Composition formula: (Al 1 -X Ti X ) O 1 -Y N Y (wherein, X is 0.05 to 0.30, Y is 0.02 to 0.10 in atomic ratio),
The highest content point of Ti and nitrogen is
Composition formula: (Ti 1-V Al V ) N 1-W O W (in terms of atomic ratio, V is 0.35 to 0.65, W is 0.02 to 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,
The highest Al and oxygen content points show excellent high temperature hardness and heat resistance due to the action of Al and oxygen, while the highest Ti and nitrogen content points ensure excellent high temperature strength with high Al content. In addition, since the distance between the highest content point of Al and oxygen and the highest content point of Ti and nitrogen is extremely small, the entire layer has excellent high-temperature hardness and heat resistance, and excellent high-temperature strength. In addition, by continuously changing the content of Al and oxygen and Ti and nitrogen (component concentration distribution structure) between the two points, for example, in the case of the conventional coated cutting tool described above, Al 2 O interface 3 layers and the TiN interlayer will be the absence, therefore, coated cutting engineering the Al-Ti oxynitride layer configurations hard layer is applied obtained by forming a hard coating layer Is a high-speed cutting with high heat generation of difficult-to-cut materials such as various stainless steels and mild steels with particularly high viscosity, and the hard coating layer is excellent without the occurrence of thermoplastic deformation that causes uneven wear at the edge of the cutting edge. To exhibit high wear resistance.
The research results shown in (a) and (b) above were obtained.
[0008]
This invention was made based on the above research results,
(A) A cutting tool made of a WC-based cemented carbide and / or a TiCN cermet is eccentrically rotated on a rotary table in an arc ion plating apparatus at a position radially away from the central axis of the rotary table. Wearing,
(B) Further, with the turntable sandwiched between them, as a cathode electrode (evaporation source), an Al—Ti alloy having a relatively high Al content and a Ti—Al alloy having a relatively high Ti content are opposed to each other. In addition, an intermediate Al / Ti alloy and an intermediate Ti / Al alloy that are lower in the Al content than the Al-Ti alloy and lower in the Ti content than the Ti-Al alloy are arranged opposite to each other. 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 in accordance with the rotational movement position of the cutting tool. The reaction atmosphere when the cutting tool is closest to the cathode electrode of the Al-Ti alloy having a relatively high Al content is the reaction atmosphere having the highest oxygen introduction ratio and the lowest nitrogen introduction ratio. On the other hand, the reaction atmosphere when the cutting tool is closest to the cathode electrode of the Ti-Al alloy having a relatively high Ti content is the reaction atmosphere having the highest nitrogen introduction ratio and the lowest oxygen introduction ratio. In addition, the cutting tool passes through the cathode electrode closest to the intermediate Al / Ti alloy from the cathode closest electrode of the Al-Ti alloy to the cathode electrode of the Ti-Al alloy. The reaction atmosphere during the rotational movement to the closest position is a continuously changing atmosphere in which the oxygen introduction ratio continuously decreases and the nitrogen introduction ratio continuously increases correspondingly, while the cutting tool is the Ti- The nitrogen introduction ratio is continuous during the reaction atmosphere during the rotational movement from the Al alloy cathode electrode closest position to the Al-Ti alloy cathode electrode closest position via the intermediate Ti / Al alloy cathode electrode closest position. In response to this, a continuously changing atmosphere in which the oxygen introduction ratio continuously increases,
(E) Therefore, on the surface of the cutting tool that rotates eccentrically while rotating on the turntable, along the layer thickness direction, the highest content point of Al and oxygen and the highest content point of Ti and nitrogen have a predetermined interval. And alternately 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. And a component concentration distribution structure in which the nitrogen content changes continuously,
Furthermore, the highest content point of Al and oxygen is
Composition formula: (Al 1 -X Ti X ) O 1 -Y N Y (wherein, X is 0.05 to 0.30, Y is 0.02 to 0.10 in atomic ratio),
The highest content point of Ti and nitrogen is
Composition formula: (Ti 1-V Al V ) N 1-W O W (in terms of atomic ratio, V is 0.35 to 0.65, W is 0.02 to 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.
A physical coating of a hard coating layer made of an Al-Ti oxynitride layer with an overall average layer thickness of 1 to 15 μm,
It is characterized by a method of forming a hard coating layer on the cutting tool surface that exhibits excellent wear resistance under high-speed cutting conditions.
[0009]
Next, the reason why the structure of the hard coating layer formed in the method of forming a hard coating layer of the present invention is limited as described above will be described.
(A) Maximum content point of Al and oxygen In the above Al-Ti oxynitride layer, the highest content point of Al and oxygen shows excellent high temperature hardness and heat resistance due to the action of high content of Al and oxygen, while Ti In addition, the highest content point of nitrogen and nitrogen shows excellent high-temperature strength by the action in the state of coexistence with Ti and nitrogen of high content Al. Therefore, at the highest content point of Al and oxygen, the combination of Ti with Al The X value indicating the content ratio in the amount is less than 0.05 by atomic ratio, or the Y value indicating the content ratio in the total amount of nitrogen and oxygen is also the atomic ratio (hereinafter the same). If it becomes less than 02, the ratio of Al and oxygen increases too much, and even if the highest content point of Ti and nitrogen having excellent high-temperature strength exists adjacent to each other, the strength of the layer itself becomes extremely low. Result chipping On the other hand, if the same X value exceeds 0.30 or the same Y value exceeds 0.10, the high temperature hardness and heat resistance are drastically reduced, which causes accelerated wear. The X value indicating the Ti content ratio was defined as 0.05 to 0.30, and the Y value indicating the nitrogen content ratio was determined as 0.02 to 0.10.
[0010]
(B) The highest content point of Ti and nitrogen As mentioned above, the highest content point of Al and oxygen has relatively good high-temperature hardness and heat resistance, but on the other hand, it has relatively low high-temperature strength. In order to make up for the lack of high temperature strength at the highest content point of Al and oxygen, the highest content points of Ti and nitrogen having excellent high temperature strength are alternately interposed in the thickness direction. However, even if the V value indicating the content ratio of the total amount of Al with Ti is less than 0.35, or even if the V value exceeds 0.65, the desired excellent high-temperature strength cannot be ensured. On the other hand, when the W value indicating the content ratio of the total amount of oxygen with nitrogen is less than 0.02, the predetermined high-temperature hardness and heat resistance cannot be secured at the highest content point of Ti and nitrogen, Causes of accelerated wear, and when the W value exceeds 0.10, the high-temperature strength suddenly decreases. Therefore, the V value indicating the Al content is 0.35 to 0.65, W value which shows a content rate was defined as 0.02-0.10.
[0011]
(C) Interval between highest content point of Al and oxygen and highest content point of Ti and nitrogen If the distance is less than 0.01 μm, it is difficult to form each point clearly with the above composition. In addition, it is impossible to ensure the desired high-temperature hardness and heat resistance and further high-temperature strength, and if the distance exceeds 0.1 μm, each point has a defect, that is, the highest content point of Al and oxygen. If the maximum content of Ti and nitrogen is insufficient, high-temperature hardness and insufficient heat resistance will appear locally in the layer, making it easier for thermoplastic deformation to occur and further promoting the progress of wear. Therefore, the interval was set to 0.01 to 0.1 μm.
[0012]
(D) Overall average layer thickness of 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 occurs on the cutting edge. Since it becomes easy, the average layer thickness was determined to be 1 to 15 μm.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Next, the method for forming a hard coating layer according to the present invention will be specifically described 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, all having an average particle diameter of 1 to 3 μm, were prepared. And then wet-mixed with a ball mill for 60 hours, dried, and press-molded into a green compact at a pressure of 100 MPa, and the green compact was vacuumed at 6 Pa at a temperature of 1420 ° C. for 1 hour. Sintered under the conditions of holding, and after the sintering, the cutting edge part is subjected to a honing process of R: 0.03, so that the throwaway made of WC-based cemented carbide having the ISO standard / CNMG120212 shape as a cutting tool Chips (hereinafter referred to as chip tools) A-1 to A-10 were formed.
[0014]
In addition, as raw material powders, TiCN (mass ratio TiC / TiN = 50/50) powder, Mo 2 C powder, ZrC powder, NbC powder, TaC powder, WC powder, all having an average particle diameter of 0.5 to 2 μm. Co powder and Ni powder are prepared, these raw material powders are blended in the blending composition shown in Table 2, 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 nitrogen atmosphere of 2 kPa at a temperature of 1520 ° C. for 1 hour, and after the sintering, the cutting edge portion was subjected to a honing process of R: 0.03 to obtain a cutting tool. As a result, chip tools B-1 to B-6 made of TiCN cermet having the shape of ISO standard / CNMG12041 were formed.
[0015]
Next, each of the above-mentioned tip tools 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. On the rotary table, it 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 a maximum compositional point of Al and oxygen having various component compositions as cathode electrodes (evaporation sources). Al-Ti alloy for forming, Ti having the same various component compositions, and Ti-Al alloy for forming points with the highest nitrogen content are arranged opposite to each other with the rotary table interposed therebetween, and further compared to the Al-Ti alloy, respectively. An intermediate Al / Ti alloy and an intermediate Ti / Al alloy, which have a low Al content and a low Ti content compared to the Ti-Al alloy, are also arranged opposite to each other. First, the device is evacuated and kept at a vacuum of 0.5 Pa or less, and the interior of the device is heated to 500 ° C. with a heater. Then, a direct current of −1000 V is applied to a tip tool that rotates while rotating on the rotary table. A bias voltage is applied and a current of 100 A is passed between the metal Ti and anode electrode of the cathode electrode to generate an arc discharge, thereby cleaning the tip tool surface with Ti bombardment, and then rotating on the rotary table. A DC bias voltage of −30V is applied to the rotating tip tool while rotating each cathode electrode (the Al—Ti alloy for forming the highest point of Al and oxygen and the Ti—Al alloy for forming the highest point of Ti and nitrogen) Further, an arc discharge is caused by flowing a current of 150 A between the intermediate Al / Ti alloy and the intermediate Ti / Al alloy) and the anode electrode. When the cutting tool is closest to the cathode electrode (evaporation source) of the Al-Ti alloy having a relatively high Al content while maintaining the pressure of the reaction atmosphere in the apparatus at 3 Pa. The reaction atmosphere is made the reaction atmosphere with the highest oxygen introduction ratio and the lowest nitrogen introduction ratio, while the cutting tool is closest to the above-mentioned Ti-Al alloy cathode electrode with a relatively high Ti content. And the cutting tool is closest to the cathode electrode of the intermediate Al / Ti alloy from the closest position of the cathode electrode of the Al-Ti alloy. The reaction atmosphere during the rotational movement to the closest position of the cathode electrode of the Ti-Al alloy through the position, the oxygen introduction rate continuously decreases, and the nitrogen introduction rate correspondingly A continuously changing atmosphere that continuously increases, while the cutting tool approaches the cathode electrode of the Al-Ti alloy through the cathode electrode closest proximity of the intermediate Ti / Al alloy from the cathode electrode closest proximity of the Ti-Al alloy. Under the conditions that the reaction atmosphere during the rotational movement to the approach position is a continuously changing atmosphere in which the nitrogen introduction ratio continuously decreases and the oxygen introduction ratio continuously increases correspondingly, Thus, Al and oxygen highest content points and Ti and nitrogen highest content points of the target composition shown in Tables 3 and 4 are alternately arranged on the surface of the chip tool along the thickness direction. And the Ti and nitrogen highest content point from the Al and oxygen highest content point, and the Al and oxygen highest content point from the Ti and nitrogen highest content point. The present invention has a component concentration distribution structure in which the contents of Al and oxygen and Ti and nitrogen change continuously, respectively, and is formed by vapor-depositing a hard coating layer having the target total layer thickness shown in Tables 3 and 4 The coated chip tool of the present invention as a coated cutting tool was produced.
[0016]
For comparison purposes, these tip tools A-1 to A-10 and B-1 to B-6 were ultrasonically cleaned in acetone and dried, and then installed in the chemical vapor deposition apparatus shown in FIG. The formation conditions of the Al 2 O 3 layer are
Reaction gas composition: (by volume) AlCl 3 : 3%, CO 2 : 7%, HCl: 3%, H 2 : remaining,
Reaction atmosphere temperature: 1000 ° C.
Reaction atmosphere pressure: 7 kPa,
And the formation conditions of the TiN layer are as follows:
Reaction gas composition: (by volume) TiCl 4 : 2%, N 2 : 55%, H 2 : remaining,
Reaction atmosphere temperature: 1000 ° C.
Reaction atmosphere pressure: 13 kPa,
As described above, a hard coating layer composed of alternately laminated Al 2 O 3 layers and TiN layers having target layer thicknesses shown in Tables 5 and 6, respectively, is also formed on the surfaces of the tip tools A1 to A10 and B1 to B6. Conventional methods 1 to 16 were performed by vapor deposition with the target total layer thickness shown in 5 and 6, respectively, and a conventional coated chip tool as a conventional coated cutting tool was manufactured.
[0017]
Next, in the state where all of the coated chip tools obtained by the present invention methods 1 to 16 and the conventional methods 1 to 16 are screwed to the tip of the tool steel tool with a fixing jig, the present invention method 1 is used. 10 and the coated tip tool obtained by the conventional methods 1-10,
Work material: JIS / SUS316 round bar,
Cutting speed: 250 m / min. ,
Incision: 1.5mm,
Feed: 0.25 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
A dry interrupted high-speed cutting test was conducted on mild steel under the following conditions.
[0018]
In addition, for the coated chip tool obtained by the above-described method 11 to 16 of the present invention and the conventional methods 11 to 16,
Work material: JIS / SUS304 round bar,
Cutting speed: 250 m / min. ,
Incision: 1.5mm,
Feed: 0.75 mm / rev. ,
Cutting time: 10 minutes,
Stainless steel dry continuous high speed cutting test under the conditions of
Work material: JIS / SUS316 lengthwise equidistant 4 round grooved round bars,
Cutting speed: 220 m / min. ,
Incision: 1.5mm,
Feed: 0.2 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: 300 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]
[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, 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 [by mass ratio, TiC / WC = 50/50] powder, and 1 .8 μm Co powders were prepared, each of these raw material powders was blended into the blending composition shown in Table 7, and then added with wax, ball milled in acetone for 60 hours, dried under reduced pressure, and then pressed into a predetermined shape at a pressure of 100 MPa. The green compacts were press-molded, and 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 6 Pa vacuum atmosphere. After holding at temperature for 1 hour, sintering under furnace cooling conditions 3 types of end mill tool-forming round bar sintered bodies having diameters of 8 mm, 13 mm, and 26 mm were formed, and the three kinds of round bar sintered bodies were combined into the combinations shown in Table 7 by grinding. The end mill tool C-1 having a four-blade square shape having a diameter x length of the cutting edge portion of 6 mm x 13 mm, 10 mm x 22 mm, and 20 mm x 45 mm, respectively, and a twist angle of 30 degrees. C-8 was produced as a cutting tool.
[0026]
Next, the surfaces of these end mill tools 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 present invention methods 17 to 24 were carried out under the same conditions, so that on the surface of the chip tool, the Al and oxygen highest content points and the Ti and nitrogen highest content points of the target composition shown in Table 8 along the thickness direction 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 and oxygen highest content point. A book having a component concentration distribution structure in which the contents of Al and oxygen and Ti and nitrogen change continuously, respectively, and a hard coating layer having a target total thickness shown in Table 8 formed by vapor deposition It was prepared present invention coated end mill tool as a light-coated cutting tool.
[0027]
For comparison purposes, the surfaces of the above-described end mill tools C-1 to C-8 were ultrasonically cleaned in acetone and dried, and then charged into the chemical vapor deposition apparatus shown in FIG. The conventional methods 17 to 24 were carried out under the same conditions as the formation conditions of the hard coating layer in Example 1, and thus a hard coating layer composed of alternating layers of Al 2 O 3 layers and TiN layers having the target layer thicknesses shown in Table 9 was prepared. A conventional coated end mill tool as a conventional coated cutting tool formed by vapor deposition on the respective surfaces of the end mill tools C-1 to C-8 with the target total layer thickness shown in Table 9 was manufactured.
[0028]
Next, with respect to the coated end mill tools obtained by the above-described inventive methods 17 to 24 and the conventional methods 17 to 24, among these, the coated end mill tools obtained by the present invention methods 17 to 19 and the conventional methods 17 to 19,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / SUS304 plate,
Cutting speed: 140 m / min. ,
Axial incision: 9mm,
Radial incision: 0.6mm,
Table feed: 600 mm / min,
With respect to the coated end mill tool obtained by the wet high-speed side cutting test of stainless steel under the conditions of the present invention, the inventive method 20-22 and the conventional method 20-22,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / S15C plate,
Cutting speed: 200 m / min. ,
Axial cut: 15mm,
Radial notch: 2mm,
Table feed: 1000 mm / min,
With respect to the coated end mill tool obtained by the wet high speed side cutting test of mild steel under the conditions of the present invention, the inventive method 23.24 and the conventional method 23.24,
Work material: Plane size: 100 mm × 250 mm, thickness: 50 mm JIS / SUS316 plate material,
Cutting speed: 120 m / min. ,
Axial cut: 30 mm,
Radial notch: 4mm,
Table feed: 750 mm / 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]
[Table 8]
[Table 9]
(Example 3)
The diameters produced in Example 2 above were 8 mm (for forming end mill tools C-1 to C-3), 13 mm (for forming end mill tools C-4 to C-6), and 26 mm (end mill tools C-7, C). -8 formation) 3 types of round bar sintered bodies were used, and from these 3 types of round bar sintered bodies, the diameter x length of the groove forming part was 4 mm x 13 mm (drill tool D) by grinding. −1 to D-3), 8 mm × 22 mm (drill tools D-4 to D-6), and 16 mm × 45 mm (drill tools D-7 and D-8), and the twist angle is 30 degrees. Drill tools D-1 to D-8 having a two-blade shape were each manufactured as a cutting tool.
[0033]
Next, honing is performed on the cutting blades of these drill tools D-1 to D-8, ultrasonic cleaning is performed in acetone, and the dried blades are inserted into the arc ion plating apparatus shown in FIG. The present invention methods 25-32 were carried out under the same conditions as in Example 1 above, and thus, on the surface of the drill tool, the Al and oxygen maximum content points and Ti of the target composition shown in Table 10 along the thickness direction. And the nitrogen highest content point alternately and repeatedly at the target intervals shown in Table 10, and from the Al and oxygen highest content point, the Ti and nitrogen highest content point, from the Ti and nitrogen highest content point, the Al and A hard coating layer having a component concentration distribution structure in which the contents of Al and oxygen and Ti and nitrogen continuously change to the highest oxygen content point, and also having the target total layer thickness shown in Table 10 The present invention coated drill tool as the present invention coated cutting tool comprising depositing formed was produced.
[0034]
For the purpose of comparison, honing is performed on the surfaces of the drill tools D-1 to D-8, ultrasonic cleaning is performed in acetone, and the surfaces of the drill tools D-1 to D-8 are dried and mounted in the chemical vapor deposition apparatus shown in FIG. Then, the conventional methods 25 to 32 are carried out under the same conditions as those for forming the hard coating layer in Example 1 above, and from the alternate lamination of Al 2 O 3 layers and TiN layers having the target layer thicknesses shown in Table 11 A conventional coated drill tool as a conventional coated cutting tool is manufactured by vapor-depositing a hard coating layer formed on each surface of the drill tools D-1 to D-8 with the target total layer thickness shown in Table 11 did.
[0035]
Next, for the coated drill tools obtained by the present invention method 25-32 and the conventional methods 25-32, among these, the coated drill tool obtained by the present invention method 25-27 and the conventional method 25-27,
Work material: Plane dimension: 100 mm x 250, thickness: 50 mm JIS S15C
Board material,
Cutting speed: 160 m / min. ,
Feed: 0.14mm / rev,
Hole depth: 8mm,
With respect to the coated drill tool obtained by the wet high speed drilling cutting test of mild steel under the conditions of the present invention, the inventive method 28-30 and the conventional method 28-30,
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,
With respect to the coated drill tool obtained by the wet high speed drilling cutting test of stainless steel under the conditions of the present invention, the present invention methods 31, 32 and the conventional methods 31, 32,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / S15C plate,
Cutting speed: 120 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]
[Table 11]
In addition, about the hard coating layer of the various coated cutting tools obtained by the said invention method 1-32 and the conventional methods 1-32, the content of Al, Ti, oxygen, and nitrogen is Auger spectroscopy along the thickness direction. When measured using an analyzer, in the hard coating layer formed by the inventive methods 1 to 32, the highest content point of Al and oxygen and the highest content point of Ti and nitrogen are substantially the same as the target values, respectively. Al, Ti, and oxygen are alternately and repeatedly present in composition and interval, and 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 was confirmed that it had a component concentration distribution structure in which the content of nitrogen continuously changed, and the average layer thickness of the hard coating layer showed substantially the same value as the target overall layer thickness. Also, in the hard coating layers of various coated cutting tools obtained by the above conventional methods 1 to 32, Al 2 O 3 layers and TiN layers having an average layer thickness substantially the same as the target layer thickness are alternately and It was confirmed that the average layer thickness was substantially the same as the total layer thickness.
[0039]
【The invention's effect】
From the results shown in Tables 3 to 11, in the above-described inventive methods 1 to 32, the hard coating layer has a relatively high temperature hardness and heat resistance relatively high in the layer thickness direction and relative to the highest content point of Al and oxygen. Ti and nitrogen highest content points having excellent high temperature strength are alternately present at predetermined intervals, and from the highest Al and oxygen content points, the highest Ti and nitrogen content points, Ti and Hard coating layer comprising an Al-Ti oxynitride layer having a component concentration distribution structure in which the contents of Al and Ti and oxygen and nitrogen continuously change from the highest nitrogen content point to the highest Al and oxygen content point, respectively The coated cutting tool formed by forming heat on 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. Plastic Without the occurrence of deformation, it showed normal wear, whereas exhibit excellent wear resistance, the in a conventional method 1-32, to form a hard coating layer comprising alternate lamination of the Al 2 O 3 layer and the TiN layer All of these coated cutting tools are caused by thermoplastic deformation at the edge of the cutting edge due to the lack of high-temperature strength of the hard coating layer. It is clear that the service life is reached in a relatively short time.
As described above, according to the method for forming a hard coating layer of the present invention, especially when cutting difficult-to-cut materials such as various stainless steels and mild steels under high speed conditions with particularly high heat generation, A hard coating layer with excellent wear resistance can be formed on the surface of the cutting tool, and the resulting coated cutting tool can fully satisfy the labor saving and energy saving of cutting work, and further cost reduction. It becomes.
[Brief description of the drawings]
FIG. 1 shows an arc ion plating apparatus which is an apparatus for carrying out the hard coating layer forming method of the present invention, wherein (a) is a schematic plan view and (b) is a schematic front view.
FIG. 2 is a schematic longitudinal sectional view showing a chemical vapor deposition apparatus which is an apparatus for performing a conventional hard coating layer forming method.
Claims (1)
（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含有量の高いＡｌ−Ｔｉ合金と、相対的にＴｉ含有量の高いＴｉ−Ａｌ合金を対向配置すると共に、それぞれ前記Ａｌ−Ｔｉ合金に比してＡｌ含有量が低く、かつ前記Ｔｉ−Ａｌ合金に比してＴｉ含有量が低い中間Ａｌ／Ｔｉ合金および中間Ｔｉ／Ａｌ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切削工具の回転移動位置に対応して調整して、前記切削工具が上記の相対的にＡｌ含有量の高いＡｌ−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、前記切削工具が上記の相対的にＴｉ含有量の高いＴｉ−Ａｌ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、前記切削工具が前記Ａｌ−Ｔｉ合金のカソード電極最接近位置から上記中間Ａｌ／Ｔｉ合金のカソード電極最接近位置を経て前記Ｔｉ−Ａｌ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、一方前記切削工具が前記Ｔｉ−Ａｌ合金のカソード電極最接近位置から上記中間Ｔｉ／Ａｌ合金のカソード電極最接近位置を経て前記Ａｌ−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切削工具の表面に、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と窒素の含有量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：（Ａｌ1-XＴｉX）Ｏ1-YＮY（ただし、原子比で、Ｘは０．０５〜０．３０、Ｙは０．０２〜０．１０）、
上記Ｔｉおよび窒素の最高含有点が、
組成式：（Ｔｉ1-VＡｌV）Ｎ1-WＯW（ただし、原子比で、Ｖは０．３５〜０．６５、Ｗ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、
ＡｌとＴｉ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すること、
を特徴とする高速切削条件ですぐれた耐摩耗性を発揮する硬質被覆層を切削工具表面に形成する方法。(A) A cutting tool made of a tungsten carbide-based cemented carbide and / or a titanium carbonitride-based cermet eccentrically placed at a position radially away from the center axis of the rotary table on the rotary table in the arc ion plating apparatus. Attached freely to rotate,
(B) Further, with the turntable sandwiched between them, as a cathode electrode (evaporation source), an Al—Ti alloy having a relatively high Al content and a Ti—Al alloy having a relatively high Ti content are opposed to each other. In addition, an intermediate Al / Ti alloy and an intermediate Ti / Al alloy, which have a lower Al content than the Al-Ti alloy and a lower Ti content than the Ti-Al alloy, are also arranged opposite to each other. 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 in accordance with the rotational movement position of the cutting tool. The reaction atmosphere when the cutting tool is closest to the cathode electrode of the Al-Ti alloy having a relatively high Al content is the reaction atmosphere having the highest oxygen introduction ratio and the lowest nitrogen introduction ratio. On the other hand, the reaction atmosphere when the cutting tool is closest to the cathode electrode of the Ti-Al alloy having a relatively high Ti content is the reaction atmosphere having the highest nitrogen introduction ratio and the lowest oxygen introduction ratio. In addition, the cutting tool passes through the cathode electrode closest to the intermediate Al / Ti alloy from the cathode closest electrode of the Al-Ti alloy to the cathode electrode of the Ti-Al alloy. The reaction atmosphere during the rotational movement to the closest position is a continuously changing atmosphere in which the oxygen introduction ratio continuously decreases and the nitrogen introduction ratio continuously increases correspondingly, while the cutting tool is the Ti- The nitrogen introduction ratio is continuous during the reaction atmosphere during the rotational movement from the Al alloy cathode electrode closest position to the Al-Ti alloy cathode electrode closest position via the intermediate Ti / Al alloy cathode electrode closest position. In response to this, a continuously changing atmosphere in which the oxygen introduction ratio continuously increases,
(E) Therefore, on the surface of the cutting tool that rotates eccentrically while rotating on the turntable, along the layer thickness direction, the highest content point of Al and oxygen and the highest content point of Ti and nitrogen have a predetermined interval. And alternately 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. And a component concentration distribution structure in which the nitrogen content changes continuously,
Furthermore, the highest content point of Al and oxygen is
Composition formula: (Al 1 -X Ti X ) O 1 -Y N Y (wherein, X is 0.05 to 0.30, Y is 0.02 to 0.10 in atomic ratio),
The highest content point of Ti and nitrogen is
Composition formula: (Ti 1-V Al V ) N 1-W O W (in terms of atomic ratio, V is 0.35 to 0.65, W is 0.02 to 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.
Physical vapor-depositing a hard coating layer composed of a composite oxynitride layer of Al and Ti with an overall average layer thickness of 1 to 15 μm;
A method of forming a hard coating layer on the surface of a cutting tool that exhibits excellent wear resistance under high-speed cutting conditions.
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