JP3928498B2

JP3928498B2 - Surface-coated cemented carbide cutting tool with excellent wear resistance under high-speed heavy cutting conditions.

Info

Publication number: JP3928498B2
Application number: JP2002183778A
Authority: JP
Inventors: 秀充高岡; 惠滋中村
Original assignee: Mitsubishi Materials Corp
Current assignee: Mitsubishi Materials Corp
Priority date: 2002-06-25
Filing date: 2002-06-25
Publication date: 2007-06-13
Anticipated expiration: 2022-06-25
Also published as: JP2004025337A

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硬さと耐熱性、さらに高強度と高靭性を有し、したがって各種の鋼や鋳鉄などの切削加工を、特に高熱発生を伴う高速で、かつ高い機械的衝撃を伴う高切り込みや高送りなどの重切削条件で行なった場合に、硬質被覆層がチッピング（微小欠け）などの発生なく、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）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、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基体（以下、これらを総称して超硬基体と云う）の表面に、組成式：（Ｔｉ_1-(M+Y)Ａｌ_MＨｆ_Y）Ｎ（ただし、原子比で、Ｍは０．４０〜０．６５、Ｙは０．０１〜０．１５を示す）を満足するＴｉとＡｌとＨｆの複合窒化物［以下、（Ｔｉ，Ａｌ，Ｈｆ）Ｎで示す］層からなる硬質被覆層を１〜１５μｍの平均層厚で物理蒸着してなる被覆超硬工具が提案され、かかる被覆超硬工具が、硬質被覆層を構成する前記（Ｔｉ，Ａｌ，Ｈｆ）Ｎ層が高温硬さおよび耐熱性（高温特性）と強度および靭性を有し、さらにＨｆ成分含有による高温強度向上と相俟って、高熱発生を伴う各種の鋼や鋳鉄などの連続切削や断続切削加工に用い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。
【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４５０℃の温度に加熱した状態で、アノード電極と所定組成を有するＴｉ−Ａｌ−Ｈｆ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−２００Ｖのバイアス電圧を印加した条件で、前記超硬合金基体の表面に、上記（Ｔｉ，Ａｌ，Ｈｆ）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知られている。
【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も強く、これに伴い、切削加工は高速化の傾向を深め、かつ高切り込みや高送りなどの重切削条件での切削加工が強く求められる傾向にあるが、上記の従来被覆超硬工具においては、これを通常の切削加工条件で用いた場合には問題はないが、特に切削加工を高速で、かつ高い機械的衝撃を伴う高切り込みや高送りなどの重切削条件で行なった場合には、硬質被覆層の高温硬さおよび耐熱性が不足し、かつ強度および靭性も不十分であるために、硬質被覆層の摩耗進行が一段と促進し、かつチッピングも発生し易くなることから、比較的短時間で使用寿命に至るのが現状である。
【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、特に高速重切削加工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開発すべく、上記の従来被覆超硬工具を構成する硬質被覆層に着目し、研究を行った結果、
（ａ）上記の図２に示されるアークイオンプレーティング装置を用いて形成された従来被覆超硬工具を構成する（Ｔｉ，Ａｌ，Ｈｆ）Ｎ層は、厚さ全体に亘って実質的に均一な組成を有し、したがって均質な高温硬さと耐熱性、さらに強度と靭性、および高温強度を有するが、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アークイオンプレーティング装置、すなわち装置中央部に超硬基体装着用回転テーブルを設け、前記回転テーブルを挟んで、一方側に相対的にＡｌ含有量の高いＡｌ−Ｔｉ−Ｈｆ合金、他方側に相対的にＴｉ含有量の高いＴｉ−Ａｌ−Ｈｆ合金をカソード電極（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の外周部に沿って複数の超硬基体をリング状に装着し、この状態で装置内雰囲気を窒素雰囲気として前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超硬基体自体も自転させながら、前記の両側のカソード電極（蒸発源）とアノード電極との間にアーク放電を発生させて、前記超硬基体の表面にＡｌとＴｉとＨｆの複合窒化物［以下、（Ａｌ−Ｔｉ，Ｈｆ）Ｎで示す］層を形成すると、この結果の（Ａｌ−Ｔｉ，Ｈｆ）Ｎ層においては、回転テーブル上にリング状に配置された前記超硬基体が上記の一方側の相対的にＡｌ含有量の高いＡｌ−Ｔｉ−Ｈｆ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最高含有点が形成され、また前記超硬基体が上記の他方側の相対的にＴｉ含有量の高いＴｉ−Ａｌ−Ｈｆ合金のカソード電極に最も接近した時点で層中にＴｉ最高含有点が形成され、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最高含有点とＴｉ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最高含有点から前記Ｔｉ最高含有点、前記Ｔｉ最高含有点から前記Ａｌ最高含有点へＡｌおよびＴｉ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つようになること。
【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，Ｈｆ）Ｎ層の形成において、対向配置の一方側のカソード電極（蒸発源）であるＡｌ−Ｔｉ−Ｈｆ合金におけるＡｌ含有量を上記の従来Ｔｉ−Ａｌ−Ｈｆ合金のＡｌ含有量に比して相対的に高いものとし、かつ同他方側のカソード電極（蒸発源）であるＴｉ−Ａｌ−Ｈｆ合金におけるＡｌ含有量を上記の従来Ｔｉ−Ａｌ−Ｈｆ合金のＡｌ含有量に比して相対的に低いものとする共に、超硬基体が装着されている回転テーブルの回転速度を制御して、
上記Ａｌ最高含有点が、組成式：（Ａｌ_1-(X+Y)Ｔｉ_XＨｆ_Y）Ｎ（ただし、原子比で、Ｘは０．０５〜０．３０、Ｙは０．０１〜０．１５を示す）、
上記Ｔｉ最高含有点が、組成式：（Ｔｉ_1-(Z+Y)Ａｌ_ZＨｆ_Y）Ｎ（ただし、原子比で、Ｚは０．１０〜０．３５、Ｙは０．０１〜０．１５を示す）、
をそれぞれ満足し、かつ隣り合う上記Ａｌ最高含有点とＴｉ最高含有点の厚さ方向の間隔を０．０１〜０．１μｍとすると、
上記Ａｌ最高含有点部分では、上記の従来（Ｔｉ，Ａｌ，Ｈｆ）Ｎ層に比してＡｌ含有量が相対的に高くなることから、より一段とすぐれた高温硬さと耐熱性を示し、一方上記Ｔｉ最高含有点部分では、前記従来（Ｔｉ，Ａｌ，Ｈｆ）Ｎ層に比してＴｉ含有量が相対的に高くなることから、一段と高い強度と靭性を具備し、かつこれらＡｌ最高含有点とＴｉ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一段とすぐれた強度と靭性、およびすぐれた高温硬さと耐熱性を具備するようになり、したがって、硬質被覆層がかかる構成の（Ａｌ−Ｔｉ，Ｈｆ）Ｎ層からなる被覆超硬工具は、Ｈｆ成分によってもたらされる高温強度の向上効果と相俟って、各種の鋼や鋳鉄などの切削加工を、特に高熱発生および高い機械的衝撃を伴う、高速重切削条件で行なった場合にも、硬質被覆層にチッピングの発生なく、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、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Ａｌ最高含有点形成用Ａｌ−Ｔｉ−Ｈｆ合金、他方側にＴｉ最高含有点形成用Ｔｉ−Ａｌ−Ｈｆ合金をカソード電極（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の外周部に沿って複数の超硬基体をリング状に装着し、この状態で装置内雰囲気を窒素雰囲気として前記回転テーブルを回転させると共に、超硬基体自体も自転させながら、前記の両側のカソード電極（蒸発源）とアノード電極との間にアーク放電を発生させて、超硬基体の表面に、（Ａｌ−Ｔｉ，Ｈｆ）Ｎ層からなる硬質被覆層を１〜１５μｍの全体平均層厚で蒸着してなる被覆超硬工具にして、
上記硬質被覆層が、層厚方向にそって、Ａｌ最高含有点とＴｉ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最高含有点から前記Ｔｉ最高含有点、前記Ｔｉ最高含有点から前記Ａｌ最高含有点へＡｌおよびＴｉ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最高含有点が、組成式：（Ａｌ_1-(X _＋Ｙ ₎Ｔｉ_ＸＨｆ_Ｙ）Ｎ（ただし、原子比で、Ｘは０．０５〜０．３０、Ｙは０．０１〜０．１５を示す）、
上記Ｔｉ最高含有点が、組成式：（Ｔｉ_1-( _Ｚ＋Ｙ ₎Ａｌ_ＺＨｆ_Ｙ）Ｎ（ただし、原子比で、Ｚは０．１０〜０．３５、Ｙは０．０１〜０．１５を示す）、
を満足し、かつ隣り合う上記Ａｌ最高含有点とＴｉ最高含有点の間隔が、０．０１〜０．１μｍである、
高速重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に特徴を有するものである。
【０００９】
つぎに、この発明の被覆超硬工具において、これを構成す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最高含有点の組成
（Ａｌ−Ｔｉ，Ｈｆ）Ｎ層のＡｌ最高含有点におけるＡｌ成分は、高温硬さおよび耐熱性を向上させ、同Ｔｉ成分は強度および靭性を向上させ、さらに同Ｈｆ成分は高温強度を向上させる作用があり、したがってＡｌ成分の含有割合が高くなればなるほど高温硬さおよび耐熱性は向上し、Ｈｆ成分による高温強度の向上効果と相俟って、高熱発生を伴う高速切削に適合したものになるが、Ｔｉの割合を示すＸ値がＡｌとＨｆの合量に占める割合（原子比）で０．０５未満になると、相対的にＡｌの割合が多くなり過ぎて、高強度および高靭性を有するＴｉ最高含有点が隣接して存在しても層自体の強度および靭性の低下は避けられず、この結果チッピングなどが発生し易くなり、一方Ｔｉ成分の割合を示すＸ値が同０．３０を越えると、相対的にＡｌの割合が少なくなり過ぎて、所望のすぐれた高温硬さおよび耐熱性を確保することができなくなるものであり、またＨｆ成分の割合を示すＹ値がＡｌとＴｉの合量に占める割合（原子比）で０．０１未満では所望の高温強度向上効果が得られず、さらに同Ｙ値が０．１５を超えると、強度および靭性が急激に低下するようになることから、Ｘ値を０．０５〜０．３０、Ｙ値を０．０１〜０．１５とそれぞれ定めた。
【００１０】
（ｂ）Ｔｉ最高含有点の組成
上記の通りＡｌ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、反面強度および靭性の劣るものであるため、このＡｌ最高含有点の強度および靭性不足を補う目的で、Ｔｉ含有割合が高く、これによって高強度および高靭性を有するようになるＴｉ最高含有点を厚さ方向に交互に介在させるものであり、したがってＡｌの割合を示すＺ値がＴｉとＨｆの合量に占める割合（原子比）で０．３５を越えると、相対的にＡｌの割合が多くなり過ぎて、所望のすぐれた強度および靭性を確保することができず、一方同Ｚ値が同じく０．１０未満になると、相対的にＴｉの割合が多くなり過ぎて、Ｔｉ最高含有点に所望の高温硬さおよび耐熱性を確保することができず、摩耗促進の原因となることから、Ｚ値を０．１０〜０．３５と定めたものであり、またＨｆ成分の割合を示すＹ値は上記のＡｌ最高含有点におけると同じ理由で０．０１〜０．１５と定めた。
【００１１】
（ｃ）Ａｌ最高含有点とＴｉ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、この結果層に一段とすぐれた強度と靭性、さらにすぐれた高温硬さと耐熱性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最高含有点であれば強度および靭性不足、Ｔｉ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、これが原因で切刃にチッピングが発生し易くなったり、摩耗進行が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、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、この発明の被覆超硬工具を実施例により具体的に説明する。
（実施例１）
原料粉末として、いずれも１〜３μｍの平均粒径を有するＷＣ粉末、ＴｉＣ粉末、ＶＣ粉末、ＴａＣ粉末、ＮｂＣ粉末、Ｃｒ₃Ｃ₂粉末、およびＣｏ粉末を用意し、これら原料粉末を、表１に示される配合組成に配合し、ボールミルで７２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：１４００℃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してＩＳＯ規格・ＳＮＭＧ１２０４１２のスローアウエイチップ形状をもったＷＣ基超硬合金製の超硬基体Ａ１〜Ａ１０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（重量比でＴｉＣ／ＴｉＮ＝５０／５０）粉末、Ｍｏ₂Ｃ粉末、ＺｒＣ粉末、ＮｂＣ粉末、ＴａＣ粉末、ＷＣ粉末、Ｃｏ粉末、およびＮｉ粉末を用意し、これら原料粉末を、表２に示される配合組成に配合し、ボールミルで７２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：１５００℃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してＩＳＯ規格・ＳＮＭＧ１２０４１２のスローアウエイチップ形状をもったＴｉＣＮ系サーメット製の超硬基体Ｂ１〜Ｂ６を形成した。
【００１５】
ついで、上記の超硬基体Ａ１〜Ａ１０およびＢ１〜Ｂ６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中心軸から半径方向に所定距離離れた外周部にそって装着し、一方側のカソード電極（蒸発源）として、種々の成分組成をもったＴｉ最高含有点形成用Ｔｉ−Ａｌ−Ｈｆ合金、他方側のカソード電極（蒸発源）として、種々の成分組成をもったＡｌ最高含有点形成用Ａｌ−Ｔｉ−Ｈｆ合金を前記回転テーブルを挟んで対向配置し、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、ついで装置内に反応ガスとして窒素ガスを導入して３Ｐａの反応雰囲気とすると共に、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Ｔｉ最高含有点形成用Ｔｉ−Ａｌ−Ｈｆ合金およびＡｌ最高含有点形成用Ａｌ−Ｔｉ−Ｈｆ合金)とアノード電極との間に１４０Ａの電流を流してアーク放電を発生させ、もって前記超硬基体の表面に、層厚方向に沿って表３，４に示される目標組成のＡｌ最高含有点とＴｉ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最高含有点から前記Ｔｉ最高含有点、前記Ｔｉ最高含有点から前記Ａｌ最高含有点へＡｌおよびＴｉ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することにより、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。
【００１６】
また、比較の目的で、これら超硬基体Ａ１〜Ａ１０およびＢ１〜Ｂ６を、アセトン中で超音波洗浄し、乾燥した状態で、それぞれ図２に示される通常のアークイオンプレーティング装置に装入し、カソード電極（蒸発源）として種々の成分組成をもったＴｉ−Ａｌ−Ｈｆ合金を装着し、さらに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４５０℃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、もって超硬基体表面をＴｉボンバート洗浄し、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−２００Ｖの直流バイアス電圧を印加し、前記カソード電極のＴｉ−Ａｌ−Ｈｆ合金とアノード電極との間に９０Ａの電流を流してアーク放電を発生させ、もって前記超硬基体Ａ１〜Ａ１０およびＢ１〜Ｂ６のそれぞれの表面に、表５，６に示される目標組成および目標層厚を有し、かつ層厚方向に沿って実質的に組成変化のない（Ｔｉ，Ａｌ，Ｈｆ）Ｎ層からなる硬質被覆層を蒸着することにより、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。
【００１７】
つぎに、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について、これ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・Ｓ２０Ｃの丸棒、
切削速度：３４０ｍ／ｍｉｎ．、
切り込み：５．７ｍｍ、
送り：０．１５ｍｍ／ｒｅｖ．、
切削時間：５分、
の条件での炭素鋼の乾式連続高速高切り込み切削加工試験、
被削材：ＪＩＳ・ＳＳ４００の長さ方向等間隔４本縦溝入り丸棒、
切削速度：３４５ｍ／ｍｉｎ．、
切り込み：１．５ｍｍ、
送り：０．５ｍｍ／ｒｅｖ．、
切削時間：５分、
の条件での軟鋼の乾式断続高速高送り切削加工試験、さらに、
被削材：ＪＩＳ・ＦＣ２００の丸棒、
切削速度：３６０ｍ／ｍｉｎ．、
切り込み：６ｍｍ、
送り：０．１８ｍｍ／ｒｅｖ．、
切削時間：５分、
の条件での鋳鉄の乾式連続高速高切り込み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７に示した。
【００１８】
【表１】

【００１９】
【表２】

【００２０】
【表３】

【００２１】
【表４】

【００２２】
【表５】

【００２３】
【表６】

【００２４】
【表７】

【００２５】
（実施例２）
原料粉末として、平均粒径：４．５μｍを有する中粗粒ＷＣ粉末、同０．７μｍ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１．８μｍのＣｒ₃Ｃ₂粉末、同１．５μｍのＶＣ粉末、同１．０μｍの（Ｔｉ，Ｗ）Ｃ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８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７２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８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、厚さ方向に沿って表９に示される目標組成のＡｌ最高含有点とＴｉ最高含有点とが交互に同じく表９に示される目標間隔で繰り返し存在し、かつ前記Ａｌ最高含有点から前記Ｔｉ最高含有点、前記Ｔｉ最高含有点から前記Ａｌ最高含有点へＡｌおよびＴｉ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９に示される目標全体層厚の硬質被覆層を蒸着することにより、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エンドミル（以下、本発明被覆超硬エンドミルと云う）１〜８をそれぞれ製造した。
【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、表１０に示される目標組成および目標層厚を有し、かつ層厚方向に沿って実質的に組成変化のない（Ｔｉ，Ａｌ，Ｈｆ）Ｎ層からなる硬質被覆層を蒸着することにより、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・ＦＣ２００の板材、
切削速度：３５０ｍ／ｍｉｎ．、
軸方向切り込み：５ｍｍ、
径方向切り込み：０．７ｍｍ、
テーブル送り：２１００ｍｍ／分、
の条件での鋳鉄の湿式高速高送り側面切削加工試験、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・ＳＳ４００の板材、
切削速度：３５５ｍ／ｍｉｎ．、
軸方向切り込み：８ｍｍ、
径方向切り込み：１ｍｍ、
テーブル送り：２０００ｍｍ／分、
の条件での軟鋼の湿式高速高送り側面切削加工試験、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・Ｓ２０Ｃの板材、
切削速度：３４０ｍ／ｍｉｎ．、
軸方向切り込み：１３ｍｍ、
径方向切り込み：１．６ｍｍ、
テーブル送り：１５００ｍｍ／分、
の条件での炭素鋼の湿式高速高送り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９、１０にそれぞれ示した。
【００２９】
【表８】

【００３０】
【表９】

【００３１】
【表１０】

【００３２】
（実施例３）
上記の実施例２で製造した直径が８ｍｍ（超硬基体Ｃ−１〜Ｃ−３形成用）、１３ｍｍ（超硬基体Ｃ−４〜Ｃ−６形成用）、および２６ｍｍ（超硬基体Ｃ−７、Ｃ−８形成用）の３種の丸棒焼結体を用い、この３種の丸棒焼結体から、研削加工にて、溝形成部の直径×長さがそれぞれ４ｍｍ×１３ｍｍ（超硬基体Ｄ−１〜Ｄ−３）、８ｍｍ×２２ｍｍ（超硬基体Ｄ−４〜Ｄ−６）、および１６ｍｍ×４５ｍｍ（超硬基体Ｄ−７、Ｄ−８）の寸法、並びにいずれもねじれ角：３０度の２枚刃形状をもった超硬基体（ドリル）Ｄ−１〜Ｄ−８をそれぞれ製造した。
【００３３】
ついで、これらの超硬基体（ドリル）Ｄ−１〜Ｄ−８の切刃に、ホーニングを施し、アセトン中で超音波洗浄し、乾燥した状態で、同じく図１に示されるアークイオンプレーティング装置に装入し、上記実施例１と同一の条件で、層厚方向に沿って表１１に示される目標組成のＡｌ最高含有点とＴｉ最高含有点とが交互に同じく表１１に示される目標間隔で繰り返し存在し、かつ前記Ａｌ最高含有点から前記Ｔｉ最高含有点、前記Ｔｉ最高含有点から前記Ａｌ最高含有点へＡｌおよびＴｉ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１１に示される目標全体層厚の硬質被覆層を蒸着することにより、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ドリル（以下、本発明被覆超硬ドリルと云う）１〜８をそれぞれ製造した。
【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、表１２に示される目標組成および目標層厚を有し、かつ層厚方向に沿って実質的に組成変化のない（Ｔｉ，Ａｌ，Ｈｆ）Ｎ層からなる硬質被覆層を蒸着することにより、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×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＳＳ４００の板材、
切削速度：２３０ｍ／ｍｉｎ．、
送り：０．５ｍｍ／ｒｅｖ、
穴深さ：１０ｍｍ、
の条件での軟鋼の湿式高速高送り穴あけ切削加工試験、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・Ｓ２０Ｃの板材、
切削速度：２４０ｍ／ｍｉｎ．、
送り：０．５５ｍｍ／ｒｅｖ、
穴深さ：１５ｍｍ、
の条件での炭素鋼の湿式高速高送り穴あけ切削加工試験、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・ＦＣ２００の板材、
切削速度：２５０ｍ／ｍｉｎ．、
送り：０．６ｍｍ／ｒｅｖ、
穴深さ：３０ｍｍ、
の条件での鋳鉄の湿式高速高送り穴あけ切削加工試験、をそれぞれ行い、いずれの湿式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１１、１２にそれぞれ示した。
【００３６】
【表１１】

【００３７】
【表１２】

【００３８】
この結果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を構成する硬質被覆層におけるＡｌ最高含有点とＴｉ最高含有点の組成、並びに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の硬質被覆層の組成をオージェ分光分析装置を用いて測定したところ、それぞれ目標組成と実質的に同じ組成を示した。
また、これらの本発明被覆超硬工具の硬質被覆層におけるＡｌ最高含有点とＴｉ最高含有点間の間隔、およびこれの全体層厚、並びに従来被覆超硬工具の硬質被覆層の厚さを、走査型電子顕微鏡を用いて断面測定したところ、いずれも目標値と実質的に同じ値を示した。
【００３９】
【発明の効果】
表３〜１２に示される結果から、硬質被覆層が厚さ方向に、相対的に一段とすぐれた高温硬さと耐熱性を有するＡｌ最高含有点と、同じく相対的に高い強度と靭性を有するＴｉ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最高含有点から前記Ｔｉ最高含有点、前記Ｔｉ最高含有点から前記Ａｌ最高含有点へＡｌおよびＴｉ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本発明被覆超硬工具は、いずれも前記硬質被覆層がＨｆ成分の含有によってすぐれた高温強度を具備することと相俟って、各種の鋼や鋳鉄などの切削加工を、高温発生を伴う高速条件で、かつ高い機械的衝撃を伴う高切り込みや高送りなどの重切削条件で行なった場合にも、硬質被覆層にチッピングの発生なく、すぐれた耐摩耗性を発揮するのに対して、硬質被覆層が厚さ方向に沿って実質的に組成変化のない（Ｔｉ，Ａｌ，Ｈｆ）Ｎ層からなる従来被覆超硬工具においては、前記の高速重切削条件では、前記硬質被覆層の高温硬さおよび耐熱性不足、さらに強度および靭性不足が原因で、摩耗進行が速く、かつチッピングも発生することから、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、この発明の被覆超硬工具は、通常の条件での切削加工は勿論のこと、特に各種の鋼や鋳鉄などの切削加工を、高熱発生および高い機械的衝撃を伴う高速重切削条件で行なった場合にも、チッピングの発生なく、すぐれた耐摩耗性を発揮するものであるから、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である。
【図面の簡単な説明】
【図１】この発明の被覆超硬工具を構成する硬質被覆層を形成するのに用いたアークイオンプレーティング装置を示し、（ａ）は概略平面図、（ｂ）は概略正面図である。
【図２】従来被覆超硬工具を構成する硬質被覆層を形成するのに用いた通常のアークイオンプレーティング装置の概略説明図である。[0001]
BACKGROUND OF THE INVENTION
This invention has excellent high temperature hardness and heat resistance, and high strength and toughness due to its hard coating layer. Therefore, cutting of various types of steel and cast iron, especially at high speed with high heat generation and high mechanical strength. A surface-coated cemented carbide cutting tool that exhibits excellent wear resistance without the occurrence of chipping (microchips) in the hard coating layer when performed under heavy cutting conditions such as high cutting with impact and high feed ( Hereinafter, it is related to a coated carbide tool.
[0002]
[Prior art]
In general, coated carbide tools are used for throwaway inserts that are detachably attached to the tip of a cutting tool for drilling and cutting of various materials such as steel and cast iron, and for flat cutting. There are drills, miniature drills, solid type end mills used for chamfering, grooving, shoulder processing, etc. Also, the throwaway tip is detachably attached and cutting is performed in the same way as the solid type end mill Throwaway end mill tools are known.
[0003]
Further, as a coated carbide tool, a substrate made of tungsten carbide (hereinafter referred to as WC) -based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) -based cermet (hereinafter collectively referred to as a cemented carbide substrate). ) On the surface of the composition formula: (Ti _{1- (M + Y)} Al _M Hf _Y ) N (however, in atomic ratio, M is 0.40 to 0.65, Y is 0.01 to 0.15) A hard coating layer composed of a composite nitride of Ti, Al, and Hf (hereinafter referred to as (Ti, Al, Hf) N) satisfying the above condition is physically deposited with an average layer thickness of 1 to 15 μm. A hard tool is proposed, and in the coated carbide tool, the (Ti, Al, Hf) N layer constituting the hard coating layer has high-temperature hardness and heat resistance (high-temperature characteristics), strength and toughness, and further Hf Combined with the improvement of high-temperature strength due to the inclusion of components, various steels and cast irons with high heat generation It is also known to exert the continuous cutting or intermittent cutting work cutting performance with superior when used in.
[0004]
Furthermore, the above-mentioned coated carbide tool is, for example, the above-mentioned carbide substrate is inserted into an arc ion plating apparatus which is one type of physical vapor deposition apparatus schematically shown in FIG. For example, an arc discharge is generated between the anode electrode and a cathode electrode (evaporation source) in which a Ti—Al—Hf alloy having a predetermined composition is set, for example, at a current of 90 A, while being heated to a temperature of 450 ° C. At the same time, nitrogen gas is introduced into the apparatus as a reaction gas to form a reaction atmosphere of, for example, 2 Pa. On the other hand, the surface of the cemented carbide substrate is applied to the cemented carbide substrate with a bias voltage of, for example, −200 V applied. In addition, it is also known to be produced by vapor-depositing a hard coating layer composed of the (Ti, Al, Hf) N layer.
[0005]
[Problems to be solved by the invention]
In recent years, there has been a remarkable increase in performance of cutting devices. On the other hand, there is a strong demand for labor saving, energy saving, and cost reduction for cutting processing. Although there is a tendency to require cutting under heavy cutting conditions such as high feed, there is no problem when using the above conventional coated carbide tools under normal cutting conditions. When processing is performed at high speed and under heavy cutting conditions such as high cutting and high feed with high mechanical impact, the high temperature hardness and heat resistance of the hard coating layer are insufficient, and the strength and toughness are also insufficient. Therefore, the progress of wear of the hard coating layer is further promoted, and chipping is likely to occur, so that the service life is reached in a relatively short time.
[0006]
[Means for Solving the Problems]
In view of the above, the present inventors have developed the above-mentioned conventional coated carbide tool in order to develop a coated carbide tool that exhibits excellent wear resistance with a hard coating layer particularly under high-speed heavy cutting conditions. As a result of conducting research focusing on the hard coating layer that composes
(A) The (Ti, Al, Hf) N layer constituting the conventional coated carbide tool formed using the arc ion plating apparatus shown in FIG. 2 is substantially uniform over the entire thickness. Therefore, it has uniform high temperature hardness and heat resistance, strength and toughness, and high temperature strength. For example, it is shown in a schematic plan view in FIG. 1 (a) and in a schematic front view in (b). An arc ion plating apparatus having a structure, that is, a rotating table for mounting a carbide substrate is provided at the center of the apparatus, and an Al—Ti—Hf alloy having a relatively high Al content is disposed on one side of the rotating table, and the other side. And an arc ion plating apparatus in which a Ti—Al—Hf alloy having a relatively high Ti content is disposed as a cathode electrode (evaporation source), and a plurality of carbides are disposed along the outer periphery of the rotary table of the apparatus. While the body is mounted in a ring shape, the rotary table is rotated by setting the atmosphere inside the apparatus as a nitrogen atmosphere, and the carbide substrate itself is rotated for the purpose of uniformizing the thickness of the hard coating layer formed by vapor deposition. An arc discharge is generated between the cathode electrode (evaporation source) and the anode electrode on both sides, and a composite nitride of Al, Ti and Hf [hereinafter referred to as (Al-Ti, Hf) on the surface of the cemented carbide substrate. ) N]] layer is formed, the resulting (Al—Ti, Hf) N layer has a relatively Al content on one side of the carbide substrate disposed in a ring shape on the rotary table. At the point closest to the cathode electrode (evaporation source) of the Al-Ti-Hf alloy having a high amount, the highest Al content point is formed in the layer, and the carbide substrate has a relatively Ti content on the other side. High Ti-Al-Hf alloy At the point closest to the cathode electrode, a Ti highest content point is formed in the layer, and the rotation of the rotary table causes the Al highest content point and the Ti highest content point to alternate in the thickness direction along the thickness direction. And a concentration distribution structure in which the Al and Ti contents continuously change from the highest Al content point to the highest Ti content point and from the highest Ti content point to the highest Al content point. thing.
[0007]
(B) In the formation of the (Al—Ti, Hf) N layer having the repeated continuous change component concentration distribution structure of (a) above, in the Al—Ti—Hf alloy which is the cathode electrode (evaporation source) on one side of the opposing arrangement Al content in the Ti-Al-Hf alloy, which is the cathode electrode (evaporation source) on the other side, which is relatively higher than the Al content of the conventional Ti-Al-Hf alloy. The amount is relatively low compared to the Al content of the conventional Ti-Al-Hf alloy, and the rotational speed of the turntable on which the carbide substrate is mounted is controlled,
The Al highest content point is the composition formula: (Al _{1-(X + Y)} Ti _X Hf _Y ) N (wherein, in terms of atomic ratio, X is 0.05 to 0.30, and Y is 0.01 to 0.00. 15)
The Ti maximum content point, composition _{formula: (Ti 1- (Z + Y} ) Al Z Hf Y) N ( provided that an atomic ratio, Z is 0.10 to 0.35, Y is from 0.01 to 0. 15)
And the interval in the thickness direction of the adjacent Al highest content point and Ti highest content point adjacent to each other is 0.01 to 0.1 μm,
In the Al highest content point portion, since the Al content is relatively higher than that of the conventional (Ti, Al, Hf) N layer, it exhibits higher temperature hardness and heat resistance. In the Ti highest content point portion, the Ti content is relatively higher than that of the conventional (Ti, Al, Hf) N layer, so that it has higher strength and toughness, and these Al highest content points. Since the interval between the highest Ti content points is extremely small, the entire layer has excellent strength and toughness, and excellent high-temperature hardness and heat resistance. Coated carbide tools composed of an Al—Ti, Hf) N layer, combined with the effect of improving the high-temperature strength caused by the Hf component, are capable of cutting various steels and cast irons, especially with high heat generation and high mechanical properties. Opposition The associated high speed when conducted in heavy cutting conditions even without the occurrence of chipping in the hard coating layer, to become to exert excellent wear resistance.
The research results shown in (a) and (b) above were obtained.
[0008]
The present invention has been made based on the above research results, and is provided with a rotating table for mounting a carbide substrate at the center of the apparatus, sandwiching the rotating table, and Al— Using an arc ion plating apparatus in which a Ti—Hf alloy and a Ti—Al—Hf alloy for forming the highest Ti content point on the other side are arranged to face each other as a cathode electrode (evaporation source), along the outer peripheral portion of the rotary table of this apparatus A plurality of carbide substrates are mounted in a ring shape, and in this state, the atmosphere inside the apparatus is changed to a nitrogen atmosphere, the rotary table is rotated, and the carbide substrates themselves are rotated, while the cathode electrodes (evaporation sources) on both sides are rotated. and by generating arc discharge between the anode electrode, the surface of the carbide substrate, depositing a hard coating layer made of (Al-Ti, Hf) N layer with overall average layer thickness of 1~15μm And to become coated carbide tools,
In the hard coating layer, the highest Al content point and the highest Ti content point are repeatedly present at predetermined intervals along the layer thickness direction, and the highest Ti content point, the highest Ti content point, and the highest Ti content point A component concentration distribution structure in which the Al and Ti contents continuously change from the highest content point to the Al highest content point, respectively,
The Al highest content point is the composition formula: (Al _{1− (X} _{+ Y} ₎ Ti _X Hf _Y ) N (however, in atomic ratio, X is 0.05 to 0.30, Y is 0.01 to 0.15) ),
The Ti maximum content point, composition _{_{formula: (Ti 1- (Z + Y}} ) Al Z Hf Y) N ( provided that an atomic ratio, Z is 0.10 to 0.35, Y is a 0.01-0.15 Show),
And the interval between the Al highest content point and the Ti highest content point adjacent to each other is 0.01 to 0.1 μm.
It is characterized by a coated carbide tool that exhibits excellent wear resistance with a hard coating layer under high-speed heavy cutting conditions.
[0009]
Next, in the coated carbide tool of the present invention, the reason why the structure of the hard coating layer constituting the tool is limited as described above will be described.
(A) Composition of Al highest content point (Al-Ti, Hf) The Al component at the Al highest content point of the N layer improves high-temperature hardness and heat resistance, and the Ti component improves strength and toughness. The Hf component has the effect of improving the high temperature strength. Therefore, the higher the content ratio of the Al component, the higher the high temperature hardness and heat resistance. However, when the X value indicating the proportion of Ti is less than 0.05 as the proportion of the total amount of Al and Hf (atomic ratio), the proportion of Al increases relatively. Thus, even if the highest Ti content point having high strength and high toughness is present adjacently, a decrease in the strength and toughness of the layer itself is inevitable, and as a result, chipping and the like are likely to occur, while the ratio of the Ti component X value indicating If it exceeds 0.30, the proportion of Al becomes relatively small, and the desired excellent high temperature hardness and heat resistance cannot be secured, and the Y value indicating the proportion of the Hf component is If the ratio (atomic ratio) to the total amount of Al and Ti is less than 0.01, the desired high-temperature strength improvement effect cannot be obtained, and if the Y value exceeds 0.15, the strength and toughness are rapidly reduced. Therefore, the X value was set to 0.05 to 0.30, and the Y value was set to 0.01 to 0.15.
[0010]
(B) Composition of highest Ti content point As described above, the highest Al content point has excellent high-temperature hardness and heat resistance, but on the other hand, it is inferior in strength and toughness, so the strength and toughness of this Al highest content point are insufficient. In order to compensate for this, the Ti maximum content point having a high Ti content and thereby high strength and high toughness is alternately interposed in the thickness direction. Therefore, the Z value indicating the Al content is Ti. When the ratio (atomic ratio) of the total amount of Hf and Hf exceeds 0.35, the ratio of Al becomes relatively large, and the desired excellent strength and toughness cannot be ensured. If the value is also less than 0.10, the ratio of Ti is relatively increased, and the desired high-temperature hardness and heat resistance cannot be secured at the highest Ti content point, which may cause wear acceleration. From the Z value Are as hereinbefore defined and .10～0.35 and Y value indicating a ratio of the Hf component is specified to be 0.01 to 0.15 for the same reason as in Al highest content point of the.
[0011]
(C) Interval between the highest Al content point and the highest Ti content point If the distance is less than 0.01 μm, it is difficult to clearly form each point with the above composition. It becomes impossible to ensure toughness, excellent high temperature hardness and heat resistance, and if the distance exceeds 0.1 μm, each point has defects, that is, if Al is the highest content point, insufficient strength and toughness, Ti highest If it is included, high temperature hardness and insufficient heat resistance will appear locally in the layer, and this may cause chipping on the cutting edge and promote wear progress. It was determined to be 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, desired wear resistance cannot be ensured. On the other hand, if the average layer thickness exceeds 15 μm, chipping tends to occur. Therefore, the average layer thickness was determined to be 1 to 15 μm.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Next, the coated carbide tool of 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 72 hours, dried, and press-molded into a green compact at a pressure of 100 MPa. The green compact was vacuumed at 6 Pa at a temperature of 1400 ° C. for 1 hour. Sintered under holding conditions, and after sintering, the cutting edge portion is subjected to a honing process of R: 0.03 and has a throwaway tip shape of ISO standard / SNMG120212, and a cemented carbide substrate A1 made of WC-based cemented carbide -A10 was formed.
[0014]
In addition, as raw material powders, all are TiCN (weight ratio TiC / TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC powder having an average particle diameter of 0.5 to 2 μm. Co powder and Ni powder were prepared, and these raw material powders were blended in the blending composition shown in Table 2, wet mixed by a ball mill for 72 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 1500 ° C. for 1 hour, and after sintering, the cutting edge portion was subjected to a honing process of R: 0.03 and ISO standard / SNMG120204. TiCN-based cermet carbide substrates B1 to B6 having the shape of the throwaway tip were formed.
[0015]
Next, each of the above-mentioned carbide substrates A1 to A10 and B1 to B6 is ultrasonically cleaned in acetone and dried, and is then placed on the rotary table in the arc ion plating apparatus shown in FIG. Ti-Al-Hf alloy for forming the highest Ti content point with various components as cathode electrode (evaporation source) on one side, mounted along the outer peripheral part at a predetermined distance in the radial direction, cathode on the other side As an electrode (evaporation source), Al-Ti-Hf alloys for forming the highest Al content point having various component compositions are arranged opposite to each other with the rotary table interposed therebetween, and a metal Ti for bombard cleaning is also mounted. The inside of the apparatus is heated to 500 ° C. with a heater while evacuating the interior and kept at a vacuum of 0.5 Pa or less, and then applied to a carbide substrate that rotates while rotating on the rotary table at −1000 V. A current bias voltage is applied and a current of 100 A is passed between the metal Ti and the anode electrode of the cathode electrode to generate an arc discharge, thereby cleaning the surface of the carbide substrate by Ti bombarding, and then reacting the reaction gas into the apparatus. Nitrogen gas is introduced to form a reaction atmosphere of 3 Pa, a DC bias voltage of −30 V is applied to the carbide substrate rotating while rotating on the rotary table, and each cathode electrode (the highest Ti content point) is applied. A current of 140 A is passed between the anode electrode and a Ti-Al-Hf alloy for forming and an Al-Ti-Hf alloy for forming the highest Al content point) to generate an arc discharge. Along the thickness direction, the highest Al content point and the highest Ti content point of the target composition shown in Tables 3 and 4 are alternately repeated at the target intervals shown in Tables 3 and 4. And having a component concentration distribution structure in which Al and Ti contents continuously change from the highest Al content point to the highest Ti content point, from the highest Ti content point to the highest Al content point, respectively, and By depositing a hard coating layer having a target total layer thickness shown in Tables 3 and 4, a throwaway tip made of the surface-coated cemented carbide of the present invention as a coated carbide tool of the present invention (hereinafter referred to as a coated carbide chip of the present invention). 1) to 16 were produced.
[0016]
Further, for the purpose of comparison, these carbide substrates A1 to A10 and B1 to B6 are ultrasonically cleaned in acetone and dried, and then loaded into a normal arc ion plating apparatus shown in FIG. In addition, Ti-Al-Hf alloys with various component compositions are mounted as cathode electrodes (evaporation sources), and further, bombard cleaning metal Ti is mounted. First, the inside of the apparatus is evacuated to a vacuum of 0.5 Pa or less. While being held, the inside of the apparatus was heated to 450 ° C. with a heater, a DC bias voltage of −1000 V was applied to the cemented carbide substrate, and a current of 100 A was passed between the metal Ti of the cathode electrode and the anode electrode. An arc discharge is generated, and the surface of the carbide substrate is cleaned by Ti bombardment. Then, nitrogen gas is introduced into the apparatus as a reaction gas to form a reaction atmosphere of 2 Pa. A direct current bias voltage of −200 V is applied to the substrate, and a current of 90 A is caused to flow between the Ti—Al—Hf alloy of the cathode electrode and the anode electrode to generate an arc discharge, whereby the carbide substrates A1 to A10 and From the (Ti, Al, Hf) N layer having the target composition and the target layer thickness shown in Tables 5 and 6 and having substantially no composition change along the layer thickness direction on each surface of B1 to B6 By depositing the hard coating layer, conventional surface-coated cemented carbide throwaway tips (hereinafter referred to as conventional coated carbide tips) 1 to 16 as conventional coated carbide tools were produced, respectively.
[0017]
Next, with the present invention coated carbide tips 1-16 and conventional coated carbide tips 1-16, in a state where this is screwed to the tip of the tool steel tool with a fixing jig,
Work material: JIS / S20C round bar,
Cutting speed: 340 m / min. ,
Cutting depth: 5.7 mm,
Feed: 0.15 mm / rev. ,
Cutting time: 5 minutes
Dry continuous high-speed high-cut cutting test of carbon steel under the conditions of
Work material: JIS / SS400 lengthwise equidistant 4 round bars with flutes,
Cutting speed: 345 m / min. ,
Incision: 1.5mm,
Feed: 0.5 mm / rev. ,
Cutting time: 5 minutes
Dry intermittent high-speed high-feed cutting test of mild steel under the conditions of
Work material: JIS / FC200 round bar,
Cutting speed: 360 m / min. ,
Incision: 6mm,
Feed: 0.18 mm / rev. ,
Cutting time: 5 minutes
The dry continuous high-speed, high-cut cutting test of cast iron was performed under the conditions described above, and the flank wear width of the cutting edge was measured in any cutting test. The measurement results are shown in Table 7.
[0018]
[Table 1]

[0019]
[Table 2]

[0020]
[Table 3]

[0021]
[Table 4]

[0022]
[Table 5]

[0023]
[Table 6]

[0024]
[Table 7]

[0025]
(Example 2)
As raw material powders, medium coarse WC powder having an average particle size of 4.5 μm, 0.7 μm fine WC powder, 1.3 μm TaC powder, 1.2 μm NbC powder, 1.2 μm ZrC Prepare a powder, a 1.8 μm Cr ₃ C ₂ powder, a 1.5 μm VC powder, a 1.0 μm (Ti, W) C powder, and a 1.8 μm Co powder. Each was blended in the blending composition shown in Table 8, further added with wax, mixed in a ball mill for 72 hours in acetone, dried under reduced pressure, and then press molded into various compacts of a predetermined shape at a pressure of 100 MPa. The green compact is 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, held at this temperature for 1 hour, and then fired under furnace cooling conditions. Finally, the diameters are 8mm, 13mm, and 26 m of three kinds of sintered carbide rod forming bodies for forming a carbide substrate, and by grinding from the above three kinds of round bar sintered bodies, the combinations shown in Table 8 and the diameter of the cutting edge portion X Carbide substrates (end mills) C-1 to C-8 having a four-blade square shape with lengths 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 Were manufactured respectively.
[0026]
Then, these carbide substrates (end mills) C-1 to C-8 were ultrasonically washed in acetone and dried, and then charged into the arc ion plating apparatus shown in FIG. Under the same conditions as in Example 1, the highest Al content point and the highest Ti content point of the target composition shown in Table 9 along the thickness direction alternately exist at the same target interval shown in Table 9, and It has a component concentration distribution structure in which Al and Ti contents continuously change from the highest Al content point to the highest Ti content point, and from the highest Ti content point to the highest Al content point, and is also shown in Table 9 The surface coated cemented carbide end mills (hereinafter referred to as the present coated carbide end mills) 1 to 8 as the coated carbide tools of the present invention were produced by vapor-depositing a hard coated layer having a target total layer thickness, respectively. .
[0027]
For the purpose of comparison, the above-mentioned carbide substrates (end mills) C-1 to C-8 are ultrasonically cleaned in acetone and dried, and the ordinary arc ion plating apparatus shown in FIG. 2 is also used. And having the target composition and target layer thickness shown in Table 10 under the same conditions as in Example 1, and substantially no composition change along the layer thickness direction (Ti, Al, Hf). ) End coat mills made of conventional surface-coated cemented carbide (hereinafter referred to as conventional coated cemented carbide end mills) 1 to 8 as conventional coated cemented carbide tools were produced by vapor-depositing a hard coating layer consisting of N layers.
[0028]
Next, of the present invention coated carbide end mills 1-8 and conventional coated carbide end mills 1-8, the present invention coated carbide end mills 1-3 and conventional coated carbide end mills 1-3 are as follows:
Work material: Plane dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / FC200 plate material,
Cutting speed: 350 m / min. ,
Axial cut: 5mm,
Radial notch: 0.7mm,
Table feed: 2100 mm / min,
With respect to the cast iron wet high-speed high-feed side cutting test, the coated carbide end mills 4 to 6 and the conventional coated carbide end mills 4 to 6 of the present invention,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / SS400 plate material,
Cutting speed: 355 m / min. ,
Axial cut: 8mm,
Radial notch: 1mm,
Table feed: 2000mm / min,
With respect to the wet high speed high feed side cutting test of mild steel under the following conditions, the coated carbide end mills 7 and 8 of the present invention and the conventional coated carbide end mills 7 and 8:
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / S20C plate material,
Cutting speed: 340 m / min. ,
Axial cut: 13mm,
Radial notch: 1.6mm,
Table feed: 1500mm / min,
Wet high-speed high-feed side cutting test of carbon steel under the above conditions, and the flank wear width of the outer peripheral edge of the cutting edge is an indication of the service life in any wet side cutting test (using water-soluble cutting oil) The cutting length up to 0.1 mm was measured. The measurement results are shown in Tables 9 and 10, respectively.
[0029]
[Table 8]

[0030]
[Table 9]

[0031]
[Table 10]

[0032]
(Example 3)
The diameters produced in Example 2 above were 8 mm (for forming carbide substrates C-1 to C-3), 13 mm (for forming carbide substrates C-4 to C-6), and 26 mm (for carbide substrates C-). 7, for C-8 formation), from these three types of round bar sintered bodies, the diameter x length of the groove forming portion is 4 mm x 13 mm (by grinding), respectively. Carbide substrates D-1 to D-3), 8 mm × 22 mm (Carbide substrates D-4 to D-6), and 16 mm × 45 mm (Carbide substrates D-7 and D-8), and all Carbide substrates (drills) D-1 to D-8 having a two-blade shape with a twist angle of 30 degrees were produced.
[0033]
Next, the cutting edges of these carbide substrates (drills) D-1 to D-8 are subjected to honing, ultrasonically cleaned in acetone and dried, and the arc ion plating apparatus shown in FIG. 1 is also used. In the same conditions as in Example 1 above, the target maximum distance between the Al highest content point and the Ti highest content point of the target composition shown in Table 11 along the layer thickness direction is also shown in Table 11 alternately. And a component concentration distribution structure in which Al and Ti contents continuously change from the Al highest content point to the Ti highest content point, from the Ti highest content point to the Al highest content point, respectively. Further, by vapor-depositing a hard coating layer having a target total layer thickness shown in Table 11, the drill made of the surface-coated cemented carbide of the present invention as the coated carbide tool of the present invention (hereinafter referred to as the coated carbide drill of the present invention). 1-8 Re respectively were produced.
[0034]
For comparison purposes, the cutting edges of the above-mentioned carbide substrates (drills) D-1 to D-8 are honed, ultrasonically cleaned in acetone, and dried, as shown in FIG. The sample was charged into a normal arc ion plating apparatus, had the target composition and target layer thickness shown in Table 12 under the same conditions as in Example 1, and substantially changed in composition along the layer thickness direction. By depositing a hard coating layer comprising no (Ti, Al, Hf) N layer, a conventional surface-coated cemented carbide drill (hereinafter referred to as a conventional coated carbide drill) 1-8 as a conventional coated carbide tool. Were manufactured respectively.
[0035]
Next, of the present invention coated carbide drills 1-8 and conventional coated carbide drills 1-8, the present invention coated carbide drills 1-3 and conventional coated carbide drills 1-3,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / SS400 plate material,
Cutting speed: 230 m / min. ,
Feed: 0.5mm / rev,
Hole depth: 10mm,
About the wet high speed high feed drilling test of mild steel under the conditions of the present invention, the coated carbide drills 4-6 of the present invention and the conventional coated carbide drills 4-6,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / S20C plate material,
Cutting speed: 240 m / min. ,
Feed: 0.55mm / rev,
Hole depth: 15mm,
With respect to the carbon steel wet high-speed high-feed drilling test, the coated carbide drills 7 and 8 of the present invention and the conventional coated carbide drills 7 and 8,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / FC200 plate material,
Cutting speed: 250 m / min. ,
Feed: 0.6mm / rev,
Hole depth: 30mm,
We performed a high-speed, high-feed, high-feed drilling test of cast iron under the above conditions, and in any wet drilling test (using water-soluble cutting oil), the flank wear width of the tip cutting edge surface reached 0.3 mm The number of holes drilled was measured. The measurement results are shown in Tables 11 and 12, respectively.
[0036]
[Table 11]

[0037]
[Table 12]

[0038]
In the hard coating layer which comprises this invention coated carbide tips 1-16, this invention coated carbide end mills 1-8, and this invention coated carbide drills 1-8 as this invention coated carbide tool obtained as a result. Composition of Al highest content point and Ti highest content point, and conventionally coated carbide tips 1-16 as conventionally coated carbide tools, conventionally coated carbide end mills 1-8, and hard coating of conventionally coated carbide drills 1-8 The composition of the layers was measured using an Auger spectroscopic analyzer, and each showed substantially the same composition as the target composition.
Further, the distance between the Al highest content point and the Ti highest content point in the hard coating layer of these coated carbide tools of the present invention, and the total layer thickness thereof, and the thickness of the hard coating layer of the conventional coated carbide tool, When the cross-section was measured using a scanning electron microscope, all showed substantially the same value as the target value.
[0039]
【The invention's effect】
From the results shown in Tables 3 to 12, the hardest coating layer has the highest Al content point with relatively high temperature hardness and heat resistance in the thickness direction, and the highest Ti with the same relatively high strength and toughness. Al and Ti contents are continuously present alternately from the Al highest content point to the Ti highest content point and from the Ti highest content point to the Al highest content point. The coated carbide tool of the present invention having a varying component concentration distribution structure, in combination with the fact that the hard coating layer has excellent high temperature strength due to the inclusion of the Hf component, cuts various steels and cast irons. Even when machining is performed under high-speed conditions with high temperature and heavy cutting conditions such as high cutting and high feed with high mechanical impact, the hard coating layer has excellent wear resistance without chipping. On the other hand, in the conventional coated carbide tool composed of a (Ti, Al, Hf) N layer in which the hard coating layer has substantially no composition change along the thickness direction, It is clear that due to the high-temperature hardness and heat resistance of the hard coating layer, and further due to insufficient strength and toughness, wear progresses rapidly and chipping occurs, so that the service life is reached in a relatively short time. .
As described above, the coated carbide tool of the present invention is capable of cutting various types of steel and cast iron as well as cutting under normal conditions, particularly high-speed heavy cutting with high heat generation and high mechanical impact. Even when performed under conditions, chipping does not occur and excellent wear resistance is exhibited, so that it is possible to satisfactorily cope with labor saving and energy saving of cutting work and cost reduction.
[Brief description of the drawings]
FIG. 1 shows an arc ion plating apparatus used for forming a hard coating layer constituting a coated carbide tool of the present invention, wherein (a) is a schematic plan view and (b) is a schematic front view.
FIG. 2 is a schematic explanatory view of a normal arc ion plating apparatus used to form a hard coating layer constituting a conventional coated carbide tool.

Claims

A rotating table for mounting either or both of a tungsten carbide base cemented carbide substrate and a titanium carbonitride-based cermet substrate is provided in the center of the apparatus, and the Al— Using an arc ion plating apparatus in which a Ti—Hf alloy and a Ti—Al—Hf alloy for forming the highest Ti content point on the other side are arranged to face each other as a cathode electrode (evaporation source), along the outer periphery of the rotary table of this apparatus A plurality of the substrates are mounted in a ring shape, and in this state, the atmosphere inside the apparatus is changed to a nitrogen atmosphere, the rotating table is rotated, and the substrates themselves are rotated, while the cathode electrodes (evaporation sources) and anodes on both sides are rotated. by generating arc discharge between the electrodes, the surface of the substrate, the hard coating layer made of a composite nitride layer of Al, Ti, and Hf 1 to 1 in the overall average layer surface-coated cemented carbide cutting tool comprising depositing a thickness of [mu] m,
In the hard coating layer, the highest Al content point and the highest Ti content point are repeatedly present at predetermined intervals along the layer thickness direction, and the highest Ti content point, the highest Ti content point, and the highest Ti content point A component concentration distribution structure in which the Al and Ti contents continuously change from the highest content point to the Al highest content point, respectively,
The Al highest content point is the composition formula: (Al _{1− (X} _{+ Y} ₎ Ti _X Hf _Y ) N (however, in atomic ratio, X is 0.05 to 0.30, Y is 0.01 to 0.15) ),
The Ti maximum content point, composition _{_{formula: (Ti 1- (Z + Y}} ) Al Z Hf Y) N ( provided that an atomic ratio, Z is 0.10 to 0.35, Y is a 0.01-0.15 Show),
The distance between the Al highest content point and the Ti highest content point adjacent to each other is 0.01 to 0.1 μm,
A surface-coated cemented carbide cutting tool that exhibits excellent wear resistance under high-speed heavy cutting conditions.