JP4029328B2

JP4029328B2 - Surface-coated cermet cutting tool that exhibits excellent chipping resistance with a hard coating layer under high-speed heavy cutting conditions

Info

Publication number: JP4029328B2
Application number: JP2002300334A
Authority: JP
Inventors: 浩一前田; 暁裕近藤; 裕介田中
Original assignee: Mitsubishi Materials Corp
Current assignee: Mitsubishi Materials Corp
Priority date: 2002-10-15
Filing date: 2002-10-15
Publication date: 2008-01-09
Anticipated expiration: 2022-10-15
Also published as: JP2004130495A

Description

【０００１】
【発明の属する技術分野】
この発明は、硬質被覆層が高強度を有し、かつ高温硬さと耐熱性にもすぐれ、したがって特に各種の鋼や鋳鉄などの高速切削加工を、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、硬質被覆層がすぐれた耐チッピング性を発揮する表面被覆サーメット製切削工具（以下、被覆サーメット工具という）に関するものである。
【０００２】
【従来の技術】
一般に、被覆サーメット工具には、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、被覆サーメット工具として、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）基サーメットで構成されたサーメット基体の表面に、組成式：（Ｔｉ_1-(X+Y)Ａｌ_XＢ_Y）Ｎ（ただし、原子比で、Ｘは０．４０〜０．６０、Ｙ：０．０１〜０．１０を示す）を満足するＴｉとＡｌとＢの複合窒化物［以下、（Ｔｉ，Ａｌ，Ｂ）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サーメット工具が知られており、かつ前記被覆サーメット工具の硬質被覆層である（Ｔｉ，Ａｌ，Ｂ）Ｎ層が、構成成分であるＡｌによって高温硬さと耐熱性、同Ｔｉによって強度を具備し、さらに同Ｂによる一段の高温硬さの向上効果と相俟って、これ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】
さらに、上記の被覆サーメット工具が、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サーメット基体を装入し、ヒータで装置内を、例えば５００℃の温度に加熱した状態で、アノード電極と所定組成を有するＴｉ−Ａｌ−Ｂ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、一方上記サーメット基体には、例えば−１００Ｖのバイアス電圧を印加した条件で、前記サーメット基体の表面に、上記（Ｔｉ，Ａｌ，Ｂ）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（例えば、特許文献１参照）。
【０００５】
【特許文献１】
特許第２７９３６９６号明細書
【０００６】
【発明が解決しようとする課題】
近年の切削加工装置の高性能化はめざましく、一方で切削加工に対する省力化および省エネ化、さらに低コスト化の要求は強く、これに伴い、高切り込みや高送りなどの重切削条件での切削加工でもすぐれた切削性能を発揮する被覆サーメット工具が強く求められているが、上記の従来被覆サーメット工具においては、これを通常の高速切削加工条件で用いた場合には問題はないが、高速切削加工を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、特に硬質被覆層の強度不足が原因で切刃部にチッピング（微小割れ）が発生し易く、比較的短時間で使用寿命に至るのが現状である。
【０００７】
【課題を解決するための手段】
そこで、本発明者等は、上述のような観点から、特に高速重切削加工で硬質被覆層がすぐれた耐チッピング性を発揮する被覆サーメット工具を開発すべく、上記の従来被覆サーメット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サーメット工具の硬質被覆層を構成する（Ｔｉ，Ａｌ，Ｂ）Ｎ層は、層厚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、および強度を有するが、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サーメット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、一方側に上記の従来（Ｔｉ，Ａｌ，Ｂ）Ｎ層の形成にカソード電極（蒸発源）として用いられたＴｉ−Ａｌ−Ｂ合金に相当する相対的にＡｌ含有量の高いＡｌ最高含有点形成用Ｔｉ−Ａｌ−Ｂ合金、他方側に相対的にＡｌ含有量の低いＡｌ最低含有点形成用Ｔｉ−Ａｌ−Ｂ合金をいずれもカソード電極（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の中心軸から半径方向に所定距離離れた位置にテーブルの外周部に沿って複数のサーメット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サーメット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、前記サーメット基体の表面に（Ｔｉ，Ａｌ，Ｂ）Ｎ層を形成すると、この結果の（Ｔｉ，Ａｌ，Ｂ）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サーメット基体が上記の一方側の相対的にＡｌ含有量の高いＴｉ−Ａｌ−Ｂ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、また前記サーメット基体が上記の他方側の相対的にＡｌ含有量の低いＴｉ−Ａｌ−Ｂ合金のカソード電極に最も接近した時点で層中にＡｌ最低含有点が形成され、上記回転テーブルの回転によって層中には層厚方向にそって前記Ａｌ最高含有点とＡｌ最低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Ａｌ最低含有点、前記Ａｌ最低含有点から前記Ａｌ最高含有点へＡｌ含有量が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。
【０００８】
（ｂ）上記（ａ）の繰り返し連続変化成分濃度分布構造の（Ｔｉ，Ａｌ，Ｂ）Ｎ層において、対向配置の一方側のカソード電極（蒸発源）であるＴｉ−Ａｌ−Ｂ合金におけるＡｌおよびＢ含有量を上記の従来（Ｔｉ，Ａｌ，Ｂ）Ｎ層形成用Ｔｉ−Ａｌ−Ｂ合金のＡｌおよびＢ含有量に相当するものとし、同他方側のカソード電極（蒸発源）であるＴｉ−Ａｌ−Ｂ合金におけるＡｌ含有量を上記の従来Ｔｉ−Ａｌ−Ｂ合金のＡｌ含有量に比して相対的に低いものとすると共に、サーメット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：（Ｔｉ_1-(X+Y)Ａｌ_XＢ_Y）Ｎ（ただし、原子比で、Ｘは０．４０〜０．６０、Ｙ：０．０１〜０．１０を示す）、
上記Ａｌ最低含有点が、組成式：（Ｔｉ_1-(X+Y)Ａｌ_XＢ_Y）Ｎ（ただし、原子比で、Ｘは０．１０〜０．３５、Ｙ：０．０１〜０．１０を示す）、
を満足し、かつ隣り合う上記Ａｌ最高含有点とＡｌ最低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，Ｂ）Ｎ層のもつ高温硬さと耐熱性に相当するすぐれた高温硬さと耐熱性を示し、一方上記Ａｌ最低含有点部分では、前記Ａｌ最高含有点部分に比してＡｌ含有量が低く、Ｔｉ含有量の高いものとなるので、一段と高い強度が確保され、かつこれらＡｌ最高含有点とＡｌ最低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を保持した状態で一段とすぐれた強度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（Ｔｉ，Ａｌ，Ｂ）Ｎ層からなる被覆サーメット工具は、特に各種の鋼や鋳鉄などの高速切削加工を、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、硬質被覆層がすぐれた耐チッピング性を発揮するようになること。
以上（ａ）および（ｂ）に示される研究結果を得たのである。
【０００９】
この発明は、上記の研究結果に基づいてなされたものであって、装置中央部にサーメット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Ｔｉ−Ａｌ−Ｂ合金、他方側にＡｌ最低含有点形成用Ｔｉ−Ａｌ−Ｂ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上の中心軸から半径方向に所定距離離れた位置にテーブルの外周部に沿って複数のサーメット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、前記サーメット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、前記サーメット基体の表面に、（Ｔｉ，Ａｌ，Ｂ）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サーメット工具において、
上記硬質被覆層が、層厚方向にそって、Ａｌ最高含有点とＡｌ最低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Ａｌ最低含有点、前記Ａｌ最低含有点から前記Ａｌ最高含有点へＡｌ含有量が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成分最高含有点が、組成式：（Ｔｉ_1-(X+Y)Ａｌ_XＢ_Y）Ｎ（ただし、原子比で、Ｘは０．４０〜０．６０、Ｙ：０．０１〜０．１０を示す）、
上記Ａｌ成分最低含有点が、組成式：（Ｔｉ_1-(X+Y)Ａｌ_XＢ_Y）Ｎ（ただし、原子比で、Ｘは０．１０〜０．３５、Ｙ：０．０１〜０．１０を示す）、
を満足し、かつ隣り合う上記Ａｌ最高含有点とＡｌ最低含有点の間隔が、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チッピング性を発揮する被覆サーメット工具に特徴を有するものである。
【００１０】
つぎに、この発明の被覆サーメット工具において、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最高含有点の（Ｔｉ，Ａｌ，Ｂ）ＮにおけるＴｉ成分は、強度を向上させ、同Ａｌ成分は、高温硬さおよび耐熱性を向上させ、さらに同Ｂ成分は一段と高温硬さを向上させる作用があり、したがってＡｌおよびＢ成分の含有割合が高くなればなるほど高温硬さと耐熱性は向上したものになり、高熱発生を伴う高速切削に適応したものになるが、Ａｌの含有割合を示すＸ値がＴｉとＢの合量に占める割合（原子比）で０．６０を越え、またＢの含有割合を示すＹ値が同０．１０を越えると、高強度を有するＡｌ最低含有点が隣接して存在しても層自体の強度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、一方同Ｘ値が同０．４０未満でも、また同Ｙ値が０．０１未満でも前記高温硬さと耐熱性に所望の向上効果が得られないことから、Ｘ値を０．４０〜０．６０、Ｙ値を０．０１〜０．１０と定めた。
【００１１】
（ｂ）Ａｌ最低含有点の組成
上記の通りＡｌ最高含有点は高温硬さおよび耐熱性のすぐれたものであるが、反面強度の劣るものであるため、このＡｌ最高含有点の強度不足を補う目的で、Ｔｉ含有割合が高く、一方Ａｌ含有量が低く、これによって高強度を有するようになるＡｌ最低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Ｘ値がＴｉおよびＢ成分との合量に占める割合（原子比）で０．３５を越えると、相対的にＴｉの割合が少なくなることから、所望のすぐれた強度を確保することができず、一方同Ｘ値が０．１０未満になると、Ａｌ最低含有点に所定の高温硬さおよび耐熱性を具備せしめることができなくなることから、Ａｌ最低含有点でのＡｌの割合を示すＸ値を０．１０〜０．３５と定めた。
Ａｌ最低含有点におけるＢ成分も、上記の通りＡｌ成分との共存で高温硬さを向上させ、もって高熱発生を伴う高速切削に適応させる目的で含有するものであり、したがってＹ値が０．０１未満では所望の高温硬さ向上効果が得られず、一方Ｙ値が０．１０を越えるとＡｌ最低含有点の強度に低下傾向が現れるようになり、所望の耐チッピング性向上が困難になることから、Ｙ値を０．０１〜０．１０と定めた。
【００１２】
（ｃ）Ａｌ最高含有点とＡｌ最低含有点間の間隔
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、この結果硬質被覆層に所望の高温硬さと耐熱性、さらに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最高含有点であれば強度不足、Ａｌ最低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。
【００１３】
（ｄ）硬質被覆層の全体平均層厚
その層厚が１μｍ未満では、所望の耐摩耗性を確保することができず、一方その平均層厚が１５μｍを越えると、チッピングが発生し易くなることから、その平均層厚を１〜１５μｍと定めた。
【００１４】
【発明の実施の形態】
つぎに、この発明の被覆サーメット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・ＣＮＭＧ１２０４０８のチップ形状をもったＷＣ基超硬合金製のサーメット基体Ａ１〜Ａ１０を形成した。
【００１５】
また、原料粉末として、いずれも０．５〜２μｍの平均粒径を有するＴｉＣＮ（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２４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・ＣＮＭＧ１２０４０８のチップ形状をもったＴｉＣＮ系サーメット製のサーメット基体Ｂ１〜Ｂ６を形成した。
【００１６】
ついで、上記のサーメット基体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の中心軸から半径方向に所定距離離れた位置にテーブル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Ａｌ最高含有点形成用Ｔｉ−Ａｌ−Ｂ合金、他方側のカソード電極（蒸発源）としてＡｌ最低含有点形成用Ｔｉ−Ａｌ−Ｂ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サーメット基体に−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、もってサーメット基体表面を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、前記回転テーブル上で自転しながら回転するサーメット基体に−１００Ｖ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最高含有点形成用Ｔｉ−Ａｌ−Ｂ合金およびＡｌ最低含有点形成用Ｔｉ−Ａｌ−Ｂ合金)とアノード電極との間に１００Ａの電流を流してアーク放電を発生させ、もって前記サーメット基体の表面に、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Ａｌ最低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Ａｌ最低含有点、前記Ａｌ最低含有点から前記Ａｌ最高含有点へＡｌ含有量が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、本発明被覆サーメット工具としての本発明表面被覆サーメット製スローアウエイチップ（以下、本発明被覆チップと云う）１〜１６をそれぞれ製造した。
【００１７】
また、比較の目的で、これらサーメット基体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−Ｂ合金をそれぞれ１種づつ装着し、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、前記サーメット基体に−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、もってサーメット基体表面を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、前記サーメット基体に印加するバイアス電圧を−１００Ｖに下げて、前記カソード電極とアノード電極との間にアーク放電を発生させ、もって前記サーメット基体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，Ｂ）Ｎ層からなる硬質被覆層を蒸着することにより、従来被覆サーメット工具としての従来表面被覆サーメット製スローアウエイチップ（以下、従来被覆チップと云う）１〜１６をそれぞれ製造した。
【００１８】
つぎに、上記の各種の被覆チップを、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、本発明被覆チップ１〜１０および従来被覆チップ１〜１０については、
被削材：ＪＩＳ・Ｓ４０Ｃの丸棒、
切削速度：３００ｍ／ｍｉｎ．、
切り込み：５ｍｍ、
送り：０．４ｍｍ／ｒｅｖ．、
切削時間：１０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・ＳＣＭ４３５の長さ方向等間隔４本縦溝入り丸棒、
切削速度：４００ｍ／ｍｉｎ．、
切り込み：２ｍｍ、
送り：０．６ｍｍ／ｒｅｖ．、
切削時間：５分、
の条件での合金鋼の乾式断続高速高送り切削加工試験を行なった。
【００１９】
さらに、本発明被覆チップ１１〜１６および従来被覆チップ１１〜１６については、
被削材：ＪＩＳ・ＦＣ２５０の丸棒、
切削速度：４５０ｍ／ｍｉｎ．、
切り込み：１．５ｍｍ、
送り：０．７ｍｍ／ｒｅｖ．、
切削時間：２０分、
の条件での鋳鉄の乾式連続高速高送り切削加工試験、
被削材：ＪＩＳ・ＳＮＣＭ４３９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：４．５ｍｍ、
送り：０．３５ｍｍ／ｒｅｖ．、
切削時間：５分、
の条件での合金鋼の乾式断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７，８に示した。
【００２０】
【表１】

【００２１】
【表２】

【００２２】
【表３】

【００２３】
【表４】

【００２４】
【表５】

【００２５】
【表６】

【００２６】
【表７】

【００２７】
【表８】

【００２８】
（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９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２４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種のサーメット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９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サーメット基体（エンドミル）Ｃ−１〜Ｃ−８をそれぞれ製造した。
【００２９】
ついで、これらのサーメット基体（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、層厚方向に沿って表１０に示される目標組成のＡｌ最高含有点とＡｌ最低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最高含有点から前記Ａｌ最低含有点、前記Ａｌ最低含有点から前記Ａｌ最高含有点へＡｌ含有量が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することにより、本発明被覆サーメット工具としての本発明表面被覆サーメット製エンドミル（以下、本発明被覆エンドミルと云う）１〜８をそれぞれ製造した。
【００３０】
また、比較の目的で、上記のサーメット基体（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１１に示される目標組成および目標層厚を有し、かつ層厚方向に沿って実質的に組成変化のない（Ｔｉ，Ａｌ，Ｂ）Ｎ層からなる硬質被覆層を蒸着することにより、従来被覆サーメット工具としての従来表面被覆サーメット製エンドミル（以下、従来被覆エンドミルと云う）１〜８をそれぞれ製造した。
【００３１】
つぎに、上記本発明被覆エンドミル１〜８および従来被覆エンドミル１〜８のうち、本発明被覆エンドミル１〜３および従来被覆エンドミル１〜３については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＳＫＤ６１の板材、
切削速度：１５０ｍ／ｍｉｎ．、
溝深さ（切り込み）：３ｍｍ、
テーブル送り：４００ｍｍ／分、
の条件での工具鋼の乾式高速高切り込み溝切削加工試験、本発明被覆エンドミル４〜６および従来被覆エンドミル４〜６については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＳＣＭ４２０の板材、
切削速度：２００ｍ／ｍｉｎ．、
溝深さ（切り込み）：６ｍｍ、
テーブル送り：５５０ｍｍ／分、
の条件での合金鋼の乾式高速高切り込み溝切削加工試験、本発明被覆エンドミル７，８および従来被覆エンドミル７，８については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・Ｓ５５Ｃの板材、
切削速度：１８０ｍ／ｍｉｎ．、
溝深さ（切り込み）：３ｍｍ、
テーブル送り：５００ｍｍ／分、
の条件での炭素鋼の乾式高速高送り溝切削加工試験をそれぞれ行い、いずれの溝切削加工試験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に至るまでの切削溝長を測定した。この測定結果を表１０，１１にそれぞれ示した。
【００３２】
【表９】

【００３３】
【表１０】

【００３４】
【表１１】

【００３５】
（実施例３）
上記の実施例２で製造した直径が８ｍｍ（サーメット基体Ｃ−１〜Ｃ−３形成用）、１３ｍｍ（サーメット基体Ｃ−４〜Ｃ−６形成用）、および２６ｍｍ（サーメット基体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（サーメット基体Ｄ−１〜Ｄ−３）、８ｍｍ×２２ｍｍ（サーメット基体Ｄ−４〜Ｄ−６）、および１６ｍｍ×４５ｍｍ（サーメット基体Ｄ−７、Ｄ−８）の寸法、並びにいずれもねじれ角：３０度の２枚刃形状をもったサーメット基体（ドリル）Ｄ−１〜Ｄ−８をそれぞれ製造した。
【００３６】
ついで、これらのサーメット基体（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１２に示される目標組成のＡｌ最高含有点とＡｌ最低含有点とが交互に同じく表１２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Ａｌ最低含有点、前記Ａｌ最低含有点から前記Ａｌ最高含有点へＡｌ含有量が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１２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、本発明被覆サーメット工具としての本発明表面被覆サーメット製ドリル（以下、本発明被覆ドリルと云う）１〜８をそれぞれ製造した。
【００３７】
また、比較の目的で、上記のサーメット基体（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１３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，Ｂ）Ｎ層からなる硬質被覆層を蒸着することにより、従来被覆サーメット工具としての従来表面被覆サーメット製ドリル（以下、従来被覆ドリルと云う）１〜８をそれぞれ製造した。
【００３８】
つぎに、上記本発明被覆ドリル１〜８および従来被覆ドリル１〜８のうち、本発明被覆ドリル１〜３および従来被覆ドリル１〜３については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・Ｓ５０Ｃの板材、
切削速度：１８０ｍ／ｍｉｎ．、
送り：０．２ｍｍ／ｒｅｖ、
穴深さ：８ｍｍ
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、本発明被覆ドリル４〜６および従来被覆ドリル４〜６については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＦＣ２５０の板材、
切削速度：２００ｍ／ｍｉｎ．、
送り：０．３ｍｍ／ｒｅｖ、
穴深さ：１６ｍｍ
の条件での鋳鉄の湿式高速高送り穴あけ切削加工試験、本発明被覆ドリル７，８および従来被覆ドリル７，８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：１８０ｍ／ｍｉｎ．、
送り：０．４ｍｍ／ｒｅｖ、
穴深さ：３２ｍｍ
の条件での構造用鋼の湿式高速高送り穴あけ切削加工試験、をそれぞれ行い、いずれの湿式高速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１２，１３にそれぞれ示した。
【００３９】
【表１２】

【００４０】
【表１３】

【００４１】
この結果得られた本発明被覆サーメット工具としての本発明被覆チップ１〜１６、本発明被覆エンドミル１〜８、および本発明被覆ドリル１〜８を構成する硬質被覆層におけるＡｌ最高含有点とＡｌ最低含有点の組成、並びに従来被覆サーメット工具としての従来被覆チップ１〜１６、従来被覆エンドミル１〜８、および従来被覆ドリル１〜８の硬質被覆層について、厚さ方向に沿ってＴｉ、Ａｌ、およびＢ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、本発明被覆サーメット工具の硬質被覆層では、Ａｌ最高含有点とＡｌ最低含有点とがそれぞれ目標値と実質的に同じ組成および間隔で交互に繰り返し存在し、かつ前記Ａｌ最高含有点から前記Ａｌ最低含有点、前記Ａｌ最低含有点から前記Ａｌ最高含有点へＡｌ成分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、また硬質被覆層の全体平均層厚も目標全体層厚と実質的に同じ値を示した。
一方前記従来被覆サーメット工具の硬質被覆層では厚さ方向に沿って組成変化が見られず、かつ目標組成と実質的に同じ組成および目標全体層厚と実質的に同じ全体平均層厚を示すことが確認された。
【００４２】
【発明の効果】
表３〜１３に示される結果から、硬質被覆層が層厚方向に、すぐれた高温硬さと耐熱性を有するＡｌ最高含有点と高強度を有するＡｌ最低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Ａｌ最低含有点、前記Ａｌ最低含有点から前記Ａｌ最高含有点へＡｌ含有量が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サーメット工具は、いずれも各種の鋼や鋳鉄などの高速切削加工を、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、硬質被覆層がすぐれた耐チッピング性を発揮するのに対して、硬質被覆層が層厚方向に沿って実質的に組成変化のない（Ｔｉ，Ａｌ，Ｂ）Ｎ層からなる従来被覆サーメット工具においては、前記硬質被覆層がすぐれた高温硬さと耐熱性を有するものの、強度に劣るものであるために、チッピングが発生し、これが原因で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、この発明の被覆サーメット工具は、通常の条件での高速切削加工は勿論のこと、特に各種の鋼や鋳鉄などの高速切削加工を、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、すぐれた耐チッピング性を発揮し、長期に亘ってすぐれた耐摩耗性を示すものであるから、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】この発明の被覆サーメット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】従来被覆サーメット工具を構成する硬質被覆層を形成するのに用いた通常のアークイオンプレーティング装置の概略説明図である。[0001]
BACKGROUND OF THE INVENTION
In the present invention, the hard coating layer has high strength and is excellent in high-temperature hardness and heat resistance, and therefore, high-speed cutting such as various steels and cast irons, especially high cutting with high mechanical impact, high feed, etc. The present invention also relates to a surface-coated cermet cutting tool (hereinafter referred to as a coated cermet tool) that exhibits excellent chipping resistance even when performed under heavy cutting conditions.
[0002]
[Prior art]
Generally, for coated cermet tools, drills used for slow-away inserts that are detachably attached to the tip of a bite for turning and planing of various steel and cast iron, drills for drilling, etc. And miniature drills, as well as solid type end mills used for chamfering, grooving, shoulder processing, etc. Also, the throwaway tip is detachably attached and the throw is performed in the same manner as the solid type endmill. Way end mill tools are known.
[0003]
Further, as a coated cermet tool, a composition formula (Ti) is formed on the surface of a cermet base composed of a tungsten carbide (hereinafter referred to as WC) -based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) -based cermet. _{1- (X + Y)} Al _X B _Y ) Ti, Al and B composite nitride satisfying N (wherein X represents 0.40 to 0.60, Y: 0.01 to 0.10 in atomic ratio) [hereinafter referred to as (Ti, Al , B) a coated coating cermet tool obtained by physically vapor-depositing a hard coating layer comprising a layer with an average layer thickness of 1 to 15 μm is known, and is a hard coating layer of the coated cermet tool (Ti, Al, B) N layer has high-temperature hardness and heat resistance by Al as a constituent component, strength by Ti, and combined with the improvement effect of one-step high-temperature hardness by the same B, It is also known to exhibit excellent cutting performance when used for continuous cutting and intermittent cutting of steel and cast iron (see, for example, Patent Document 1).
[0004]
Further, the above-described coated cermet tool is used, for example, in which the above cermet substrate is loaded into an arc ion plating apparatus which is one type of physical vapor deposition apparatus schematically shown in FIG. An arc discharge is generated between the anode electrode and a cathode electrode (evaporation source) in which a Ti—Al—B alloy having a predetermined composition is set, for example, at a current of 90 A, while being heated to a temperature of ° 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 cermet substrate is subjected to the above (Ti) on the surface of the cermet substrate under the condition that a bias voltage of, for example, −100 V is applied. , Al, B) It is also known to be manufactured by vapor-depositing a hard coating layer composed of an N layer (see, for example, Patent Document 1).
[0005]
[Patent Document 1]
Japanese Patent No. 2793696
[0006]
[Problems to be solved by the invention]
In recent years, the performance of cutting devices has been dramatically improved, but on the other hand, there is a strong demand for labor saving and energy saving and further cost reduction for cutting, and accordingly, cutting under heavy cutting conditions such as high cutting and high feed. However, there is a strong demand for a coated cermet tool that exhibits excellent cutting performance. However, the above-mentioned conventional coated cermet tool has no problem when it is used under normal high-speed cutting conditions. When cutting under heavy cutting conditions such as high cutting and high feed with high mechanical impact, chipping (microcracking) is likely to occur at the cutting edge due to insufficient strength of the hard coating layer. The current situation is that the service life is reached in a short time.
[0007]
[Means for Solving the Problems]
In view of the above, the present inventors configure the above-described conventional coated cermet tool in order to develop a coated cermet tool that exhibits excellent chipping resistance with a hard coating layer particularly excellent in high-speed heavy cutting. As a result of conducting research focusing on the hard coating layer,
(A) The (Ti, Al, B) N layer constituting the hard coating layer of the conventional coated cermet tool formed using the arc ion plating apparatus shown in FIG. For example, an arc having a structure shown in a schematic plan view in FIG. 1 (a) and a schematic front view in FIG. 1 (b). An ion plating apparatus, that is, a rotating table for mounting a cermet substrate is provided at the center of the apparatus, and the conventional (Ti, Al, B) N layer is formed on one side of the rotating table with a cathode electrode (evaporation source) interposed therebetween. Ti-Al-B alloy for forming the highest Al content point with a relatively high Al content corresponding to the Ti-Al-B alloy used as the low-Al content point formation with a relatively low Al content on the other side Ti-A Using an arc ion plating apparatus in which all of the -B alloys are arranged opposite to each other as a cathode electrode (evaporation source), along the outer periphery of the table at a predetermined distance in the radial direction from the central axis on the rotary table of the apparatus A plurality of cermet substrates are mounted in a ring shape, and in this state, the atmosphere inside the apparatus is set to a nitrogen atmosphere to rotate the rotary table, and the cermet substrate itself is also used for the purpose of uniforming the thickness of the hard coating layer formed by vapor deposition. While rotating, arc discharge was generated between the cathode electrode (evaporation source) and the anode electrode on both sides to form a (Ti, Al, B) N layer on the surface of the cermet substrate. In the (Ti, Al, B) N layer, the cermet substrate arranged in a ring shape on the rotary table has a relatively Al content on one side. At the point closest to the cathode electrode (evaporation source) of the high Ti—Al—B alloy, the highest Al content point is formed in the layer, and the cermet substrate is a Ti having a relatively low Al content on the other side. -When the Al-B alloy cathode electrode is closest to the layer, a minimum Al content point is formed in the layer, and by rotation of the rotary table, the Al maximum content point and the minimum Al content are included in the layer along the layer thickness direction. The point repeatedly appears alternately at a predetermined interval, and has a component concentration distribution structure in which the Al content continuously changes from the Al highest content point to the Al lowest content point and from the Al lowest content point to the Al highest content point. To be like that.
[0008]
(B) In the (Ti, Al, B) N layer of the repeated continuous change component concentration distribution structure of (a) above, Al in the Ti—Al—B alloy which is a cathode electrode (evaporation source) on one side facing each other The B content corresponds to the Al and B contents of the above-described conventional (Ti, Al, B) N-layer forming Ti-Al-B alloy, and Ti-- which is the cathode electrode (evaporation source) on the other side The Al content in the Al-B alloy is relatively lower than the Al content in the conventional Ti-Al-B alloy, and the rotational speed of the turntable on which the cermet substrate is mounted is controlled. And
The Al highest content point is the composition formula: (Ti _{1- (X + Y)} Al _X B _Y ) N (however, in terms of atomic ratio, X represents 0.40 to 0.60, Y represents 0.01 to 0.10),
The minimum Al content point is the composition formula: (Ti _{1- (X + Y)} Al _X B _Y ) N (however, in terms of atomic ratio, X represents 0.10 to 0.35, Y represents 0.01 to 0.10),
And the interval in the thickness direction of the adjacent Al highest content point and Al lowest content point adjacent to each other is 0.01 to 0.1 μm,
The Al highest content point portion shows excellent high temperature hardness and heat resistance corresponding to the high temperature hardness and heat resistance of the conventional (Ti, Al, B) N layer, while the Al minimum content point portion Since the Al content is lower than the highest Al content point and the Ti content is higher, a much higher strength is secured, and the distance between the highest Al content point and the lowest Al content point is extremely small. Therefore, it has a higher strength while maintaining excellent high temperature hardness and heat resistance as the characteristics of the entire layer, and therefore, the hard coating layer is composed of the (Ti, Al, B) N layer having such a configuration. Coated cermet tools are particularly resistant to chipping even when high-speed cutting of various types of steel and cast iron is performed under heavy cutting conditions such as high cutting and high feed with high mechanical impact. To become able to exert grayed property.
The research results shown in (a) and (b) above were obtained.
[0009]
This invention was made based on the above research results, A cermet substrate mounting turntable is provided at the center of the apparatus, and the Ti-Al-B alloy for forming the highest Al content point on one side and Ti-Al-B for forming the lowest Al content point on the other side across the turntable. A plurality of cermets are provided along the outer periphery of the table at a position radially spaced from the central axis on the rotary table of the device by using an arc ion plating device in which the alloy is disposed as a cathode electrode (evaporation source). In this state, the substrate is mounted in a ring shape, the atmosphere inside the apparatus is changed to a nitrogen atmosphere, the rotating table is rotated, and the cermet substrate itself is rotated, while the cathode electrode (evaporation source) and the anode electrode on both sides are rotated. With arc discharge in between A hard coating layer composed of a (Ti, Al, B) N layer is formed on the surface of the cermet substrate with an overall average layer thickness of 1 to 15 μm. Vapor deposition In the coated cermet tool,
In the hard coating layer, the Al highest content point and the Al lowest content point are present alternately at predetermined intervals along the layer thickness direction, and the Al lowest content point, the Al A component concentration distribution structure in which the Al content continuously changes from the lowest content point to the Al highest content point,
Furthermore, the highest Al component content point is the composition formula: (Ti _{1- (X + Y)} Al _X B _Y ) N (however, in terms of atomic ratio, X represents 0.40 to 0.60, Y represents 0.01 to 0.10),
The Al component minimum content point is the composition formula: (Ti _{1- (X + Y)} Al _X B _Y ) N (however, in terms of atomic ratio, X represents 0.10 to 0.35, Y represents 0.01 to 0.10),
And the interval between the Al highest content point and the Al lowest content point adjacent to each other is 0.01 to 0.1 μm.
This is characterized by a coated cermet tool that exhibits excellent chipping resistance under high-speed heavy cutting conditions.
[0010]
Next, in the coated cermet tool of the present invention, the reason why the configuration of the hard coating layer constituting the tool is limited as described above will be described.
(A) Composition of the highest Al content point
The Ti component in (Ti, Al, B) N at the highest Al content point improves the strength, the Al component improves the high temperature hardness and heat resistance, and the B component further improves the high temperature hardness. Therefore, the higher the content ratio of Al and B components, the higher the high-temperature hardness and heat resistance, and it is suitable for high-speed cutting with high heat generation. If the value exceeds 0.60 in terms of the total amount of Ti and B (atomic ratio), and if the Y value indicating the B content exceeds 0.10, the Al minimum content point with high strength is adjacent Even if it exists, a decrease in the strength of the layer itself is unavoidable, and as a result, chipping or the like is likely to occur. On the other hand, even if the X value is less than 0.40 and the Y value is less than 0.01, The desired improvement effect is obtained in high temperature hardness and heat resistance. From Ikoto, the X value 0.40 to 0.60, was defined as the Y value 0.01 to 0.10.
[0011]
(B) Composition of Al minimum content point
As described above, the highest Al content point is excellent in high-temperature hardness and heat resistance, but on the other hand, it is inferior in strength, so that the content of Ti is high in order to compensate for the insufficient strength of this Al highest content point, On the other hand, the Al minimum content point where the Al content is low and thereby has high strength is alternately interposed in the thickness direction. Therefore, the X value indicating the Al ratio is the total amount of Ti and B components. If the ratio (atomic ratio) in the ratio exceeds 0.35, the ratio of Ti becomes relatively small, so that the desired excellent strength cannot be secured, while the X value is less than 0.10. Then, since it becomes impossible to make the Al minimum content point have predetermined high-temperature hardness and heat resistance, the X value indicating the ratio of Al at the Al minimum content point was determined to be 0.10 to 0.35.
The B component at the Al minimum content point is also contained for the purpose of improving the high-temperature hardness in the coexistence with the Al component as described above, and thus adapting to high-speed cutting accompanied by the generation of high heat. If it is less than 1, the desired high-temperature hardness improvement effect cannot be obtained. On the other hand, if the Y value exceeds 0.10, the strength of the Al minimum content point tends to decrease, and it becomes difficult to improve the desired chipping resistance. Therefore, the Y value was determined to be 0.01 to 0.10.
[0012]
(C) Interval between Al highest content point and Al lowest content point
If the distance is less than 0.01 μm, it is difficult to clearly form each point with the above composition, and as a result, it is impossible to ensure the desired high temperature hardness and heat resistance and further strength to the hard coating layer, Also, when the distance exceeds 0.1 μm, the disadvantages of each point, that is, insufficient strength at the highest Al content point, insufficient high temperature hardness and insufficient heat resistance at the lowest Al content point, appear locally in the layer. Because of this, chipping is likely to occur and the progress of wear is promoted, so the interval was set to 0.01 to 0.1 μm.
[0013]
(D) Overall average layer thickness of the hard coating layer
If the layer thickness is less than 1 μm, the desired wear resistance cannot be ensured. On the other hand, if the average layer thickness exceeds 15 μm, chipping tends to occur. Therefore, the average layer thickness is 1 to 15 μm. Determined.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Next, the coated cermet tool of the present invention will be specifically described with reference to examples.
Example 1
WC powder, TiC powder, VC powder, TaC powder, NbC powder, Cr having an average particle diameter of 1 to 3 μm as raw material powders _Three C ₂ Powder and Co powder are prepared, and these raw material powders are blended in the blending composition shown in Table 1, wet mixed for 72 hours by a ball mill, dried, and then pressed into a compact at a pressure of 100 MPa. The green compact is sintered in a vacuum of 6 Pa at a temperature of 1400 ° C. for 1 hour. After sintering, the cutting edge part is subjected to a honing process of R: 0.03 to form a chip shape conforming to ISO standard CNMG120408. The cermet bases A1 to A10 made of WC base cemented carbide having the above were formed.
[0015]
In addition, as raw material powder, TiCN (TiC / TiN = 50/50 by weight) powder having an average particle diameter of 0.5 to 2 μm, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC powder, Co powder, and Ni powder are prepared. These raw material powders are blended in the blending composition shown in Table 2, and are wet-mixed for 24 hours in a ball mill and dried. After that, the green compact was press-molded into a green compact at a pressure of 100 MPa, and this green compact was sintered in a nitrogen atmosphere of 2 kPa at a temperature of 1500 ° C. for 1 hour. : 0.03 honing was performed to form cermet bases B1 to B6 made of TiCN cermet having a chip shape of ISO standard / CNMG120408.
[0016]
Next, each of the cermet substrates A1 to A10 and B1 to B6 is ultrasonically cleaned in acetone and dried, and then the cermet bases A1 to A10 and B1 to B6 have a radius from the central axis on the rotary table in the arc ion plating apparatus shown in FIG. Ti-Al-B alloy for forming the highest Al content point with various component compositions as the cathode electrode (evaporation source) on one side at a predetermined distance in the direction along the outer periphery of the table, the other side As a cathode electrode (evaporation source), a Ti-Al-B alloy for forming the lowest Al content point is disposed opposite to the rotary table, and a metallic Ti for bombard cleaning is also mounted. While maintaining the vacuum at 5 Pa or less, the inside of the apparatus is heated to 500 ° C. with a heater, and then applied to the cermet substrate 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 of the cathode electrode and the anode electrode to generate an arc discharge, thereby cleaning the surface of the cermet substrate with Ti bombardment, and then nitrogen as a reactive gas in the apparatus. A gas was introduced to form a reaction atmosphere of 2 Pa, a DC bias voltage of −100 V was applied to the cermet substrate rotating while rotating on the rotary table, and each cathode electrode (Ti for forming the highest Al content point) was applied. -Al-B alloy and Ti-Al-B alloy for forming the lowest Al content point) and an anode electrode to cause an arc discharge to flow, so that the surface of the cermet substrate has a thickness direction. Along with the targets shown in Tables 3 and 4 alternately, the Al highest content point and the Al lowest content point of the target composition shown in Tables 3 and 4 It has a component concentration distribution structure that repeatedly exists at intervals, and the Al content continuously changes from the Al highest content point to the Al lowest content point, from the Al lowest content point to the Al highest content point, and By depositing a hard coating layer having a target overall layer thickness shown in Tables 3 and 4, the surface-coated cermet throwaway tip (hereinafter referred to as the present invention-coated tip) 1-16 as the present invention-coated cermet tool. Were manufactured respectively.
[0017]
For comparison purposes, these cermet substrates A1 to A10 and B1 to B6 were ultrasonically cleaned in acetone and dried, and each was loaded into a normal arc ion plating apparatus shown in FIG. As the cathode electrode (evaporation source), one Ti-Al-B alloy with various component compositions is installed, and one bombard cleaning metal Ti is also installed. First, the inside of the apparatus is evacuated to 0.5 Pa or less. The apparatus was heated to 500 ° C. with a heater while maintaining a vacuum of −1000 V, a −1000 V DC bias voltage was applied to the cermet substrate, and a current of 100 A was applied between the metal Ti and the anode electrode of the cathode electrode. To generate an arc discharge, thereby cleaning the surface of the cermet substrate with Ti bombardment, and then introducing nitrogen gas as a reaction gas into the apparatus. And the bias voltage applied to the cermet substrate is lowered to −100 V to generate an arc discharge between the cathode electrode and the anode electrode, and thus the cermet substrates A1 to A10 and B1 to B6 A hard coating layer comprising a (Ti, Al, B) N layer having a target composition and a target layer thickness shown in Tables 5 and 6 and substantially no composition change along the layer thickness direction on each surface. The conventional surface-coated cermet throwaway tips (hereinafter referred to as conventional coated tips) 1 to 16 as conventional coated cermet tools were produced, respectively.
[0018]
Next, in the state where all the above-mentioned various coated chips are screwed to the tip of the tool steel tool with a fixing jig, the present coated chips 1 to 10 and the conventional coated chips 1 to 10 are as follows.
Work material: JIS / S40C round bar,
Cutting speed: 300 m / min. ,
Cutting depth: 5mm,
Feed: 0.4 mm / rev. ,
Cutting time: 10 minutes,
Dry continuous high-speed high-cut cutting test of carbon steel under the conditions of
Work material: JIS · SCM435 lengthwise equally spaced four round grooved round bars,
Cutting speed: 400 m / min. ,
Cutting depth: 2mm,
Feed: 0.6 mm / rev. ,
Cutting time: 5 minutes
A dry intermittent high-speed high-feed cutting test of alloy steel was performed under the following conditions.
[0019]
Furthermore, for the present coated chips 11-16 and the conventional coated chips 11-16,
Work material: JIS / FC250 round bar,
Cutting speed: 450 m / min. ,
Incision: 1.5mm,
Feed: 0.7 mm / rev. ,
Cutting time: 20 minutes,
Dry continuous high-speed high-feed cutting test of cast iron under the conditions of
Work material: JIS / SNCM439 round direction bar with 4 equal intervals in the length direction,
Cutting speed: 300 m / min. ,
Cutting depth: 4.5mm,
Feed: 0.35 mm / rev. ,
Cutting time: 5 minutes
A dry interrupted high-speed, high-cut cutting test of alloy steel 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 Tables 7 and 8.
[0020]
[Table 1]

[0021]
[Table 2]

[0022]
[Table 3]

[0023]
[Table 4]

[0024]
[Table 5]

[0025]
[Table 6]

[0026]
[Table 7]

[0027]
[Table 8]

[0028]
(Example 2)
As raw material powders, medium coarse WC powder having an average particle diameter of 5.5 μm, fine WC powder of 0.8 μm, TaC powder of 1.3 μm, NbC powder of 1.2 μm, ZrC of 1.2 μm Powder, 2.3 μm Cr _Three C ₂ Prepare powder, VC powder of 1.5 μm, (Ti, W) C powder of 1.0 μm, and Co powder of 1.8 μm, and blend these raw material powders into the composition shown in Table 9. Further, wax was added and mixed in a ball mill for 24 hours in acetone, dried under reduced pressure, and then pressed into various green compacts having a predetermined shape at a pressure of 100 MPa. These green compacts were placed in a 6 Pa vacuum atmosphere. The temperature is increased to a predetermined temperature within a range of 1370 to 1470 ° C. at a temperature increase rate of 7 ° C./min, held at this temperature for 1 hour, sintered under furnace cooling conditions, and having a diameter of 8 mm, 13 mm, and 26 mm of three types of cermet base body-forming round bar sintered bodies were formed, and from the above-mentioned three types of round bar sintered bodies, by grinding, in combinations shown in Table 9, the diameter of the cutting edge portion × Each length is 6mm x 13mm, 10mm x 22mm Dimensions and 20 mm × 45 mm, as well as any twist angle: 30 degrees 4 flute square shape with cermet substrate (end mill) C-1 through C-8 were prepared, respectively.
[0029]
Then, these cermet substrates (end mills) C-1 to C-8 were ultrasonically cleaned in acetone and dried, and then charged into the arc ion plating apparatus shown in FIG. 1, the highest Al content point and the lowest Al content point of the target composition shown in Table 10 along the layer thickness direction alternately and repeatedly exist at the target interval shown in Table 10, and the Al The target total layer thickness having a component concentration distribution structure in which the Al content continuously changes from the highest content point to the Al lowest content point, from the Al lowest content point to the Al highest content point, and also shown in Table 10 The hard coating layer of the present invention was used to produce the surface coated cermet end mills (hereinafter referred to as the present coated end mill) 1 to 8 as the present coated cermet tool.
[0030]
For comparison purposes, the above cermet substrates (end mills) C-1 to C-8 are ultrasonically cleaned in acetone and dried, and the same is applied to the ordinary arc ion plating apparatus shown in FIG. And having the target composition and target layer thickness shown in Table 11 under the same conditions as in Example 1, and substantially no composition change along the layer thickness direction (Ti, Al, B) By vapor-depositing a hard coating layer composed of an N layer, conventional surface-coated cermet end mills (hereinafter referred to as conventional coated end mills) 1 to 8 as conventional coated cermet tools were produced, respectively.
[0031]
Next, of the present invention coated end mills 1 to 8 and the conventional coated end mills 1 to 8, the present coated end mills 1 to 3 and the conventional coated end mills 1 to 3 are as follows:
Work material: Plane dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SKD61 plate material,
Cutting speed: 150 m / min. ,
Groove depth (cut): 3 mm,
Table feed: 400mm / min,
With respect to the dry high-speed, high-grooving groove cutting test of the tool steel under the conditions of the present invention, the present coated end mills 4-6 and the conventional coated end mills 4-6,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / SCM420 plate material,
Cutting speed: 200 m / min. ,
Groove depth (cut): 6 mm
Table feed: 550 mm / min,
With respect to the dry high-speed high-cut groove cutting test of alloy steel under the conditions of the present invention, the coated end mills 7 and 8 of the present invention, and the conventional coated end mills 7 and 8,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / S55C plate material,
Cutting speed: 180 m / min. ,
Groove depth (cut): 3 mm,
Table feed: 500 mm / min,
Carbon steel dry high-speed and high-feed grooving tests were performed under the above conditions, and the flank wear width of the outer peripheral edge of the cutting edge reaches 0.1 mm, which is a guide for the service life in each grooving test. The cutting groove length up to was measured. The measurement results are shown in Tables 10 and 11, respectively.
[0032]
[Table 9]

[0033]
[Table 10]

[0034]
[Table 11]

[0035]
(Example 3)
The diameters produced in Example 2 above were 8 mm (for forming cermet substrates C-1 to C-3), 13 mm (for forming cermet substrates C-4 to C-6), and 26 mm (cermet substrates C-7 and C). -8 for forming), and from these three types of round bar sintered bodies, the diameter x length of the groove forming portion is 4 mm x 13 mm (cermet substrate D) by grinding. −1 to D-3), 8 mm × 22 mm (cermet substrates D-4 to D-6), and 16 mm × 45 mm (cermet substrates D-7 and D-8), and the twist angle is 30 degrees. Cermet substrates (drills) D-1 to D-8 having a two-blade shape were produced, respectively.
[0036]
Next, the cutting blades of these cermet substrates (drills) D-1 to D-8 are subjected to honing, ultrasonically cleaned in acetone, and dried to the arc ion plating apparatus shown in FIG. In the same conditions as in Example 1 above, the highest Al content point and the lowest Al content point of the target composition shown in Table 12 along the layer thickness direction alternately at the target interval shown in Table 12 Repeatedly, and having a component concentration distribution structure in which the Al content continuously changes from the Al highest content point to the Al lowest content point, and from the Al lowest content point to the Al highest content point. The surface coated cermet drills (hereinafter referred to as the present invention coated drills) 1 to 8 as the present invention coated cermet tools are respectively deposited by vapor-depositing a hard coating layer having a target overall layer thickness shown in FIG. And elephants.
[0037]
In addition, for comparison purposes, the cutting blades of the cermet substrates (drills) D-1 to D-8 are honed, ultrasonically cleaned in acetone, and dried. And having the target composition and target layer thickness shown in Table 13 under the same conditions as in Example 1 and substantially no composition change along the layer thickness direction. By vapor-depositing a hard coating layer composed of a (Ti, Al, B) N layer, conventional surface-coated cermet drills (hereinafter referred to as conventional coated drills) 1 to 8 as conventional coated cermet tools were produced.
[0038]
Next, of the present invention coated drills 1 to 8 and the conventional coated drills 1 to 8, the present invention coated drills 1 to 3 and the conventional coated drills 1 to 3 are:
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / S50C plate material,
Cutting speed: 180 m / min. ,
Feed: 0.2mm / rev,
Hole depth: 8mm
For the wet high speed high feed drilling test of carbon steel under the conditions of the present invention, the present invention coated drills 4-6 and the conventional coated drills 4-6,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / FC250 plate material,
Cutting speed: 200 m / min. ,
Feed: 0.3mm / rev,
Hole depth: 16mm
About the wet high-speed high-feed drilling test of cast iron under the conditions of the present invention, the coated drills 7 and 8 of the present invention and the conventional coated drills 7 and 8
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / SS400 plate material,
Cutting speed: 180 m / min. ,
Feed: 0.4mm / rev,
Hole depth: 32mm
Wet high-speed high-feed drilling test of structural steel under the conditions of each, and the flank wear width of the tip cutting edge surface is 0.3 mm in any wet high-speed drilling cutting test (using water-soluble cutting oil) The number of drilling processes up to was measured. The measurement results are shown in Tables 12 and 13, respectively.
[0039]
[Table 12]

[0040]
[Table 13]

[0041]
As a result of the present invention coated chips 1-16, the present coated end mills 1-8, and the hard coated layers constituting the present coated drills 1-8 as the present coated cermet tool, the highest Al content point and the lowest Al About the composition of the content point, and the hard coating layers of the conventional coated tips 1 to 16, the conventional coated end mills 1 to 8, and the conventional coated drills 1 to 8 as a conventional coated cermet tool, along the thickness direction, Ti, Al, and When the content of B was measured using an Auger spectroscopic analyzer, the hard coating layer of the coated cermet tool of the present invention had the Al highest content point and the Al lowest content point at substantially the same composition and interval as the target values, respectively. Al component content is present alternately and from the highest Al content point to the lowest Al content point, from the lowest Al content point to the highest Al content point. It was confirmed to have a connection-varying component concentration distribution structure, also showing the overall mean layer thickness even entire target layer thickness substantially the same value of the hard layer.
On the other hand, the hard coating layer of the conventional coated cermet tool shows no composition change along the thickness direction, and shows a composition substantially the same as the target composition and an overall average layer thickness substantially the same as the target overall layer thickness. Was confirmed.
[0042]
【The invention's effect】
From the results shown in Tables 3 to 13, the hard coating layer has an Al maximum content point having excellent high temperature hardness and heat resistance and an Al minimum content point having high strength at predetermined intervals alternately in the layer thickness direction. The present coated cermet tool having a component concentration distribution structure that repeatedly exists and has an Al content continuously changing from the highest Al content point to the lowest Al content point, from the lowest Al content point to the highest Al content point, In all cases, the hard coating layer exhibits excellent chipping resistance even when high-speed cutting of various steels and cast iron is performed under heavy cutting conditions such as high cutting with high mechanical impact and high feed. On the other hand, in the conventional coated cermet tool in which the hard coating layer is composed of a (Ti, Al, B) N layer that has substantially no composition change along the layer thickness direction, the hard coating layer has excellent high-temperature hardness and Heat resistance Although having, because of inferior strength, chipping occurs and this is apparent that lead to a relatively short time service life due.
As described above, the coated cermet tool according to the present invention can be used not only for high-speed cutting under normal conditions, but also for high-speed cutting such as various steels and cast irons. Even when performed under heavy cutting conditions such as, it exhibits excellent chipping resistance and excellent wear resistance over a long period of time. It is possible to cope with the above sufficiently.
[Brief description of the drawings]
FIG. 1 shows an arc ion plating apparatus used for forming a hard coating layer constituting a coated cermet 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 cermet 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-highest content point forming Ti- Using an arc ion plating apparatus in which an Al—B alloy and a Ti—Al—B alloy for forming an Al minimum content point on the other side are arranged to face each other as a cathode electrode (evaporation source), from the central axis on the rotary table of the apparatus A plurality of the bases are mounted in a ring shape along the outer periphery of the table at a predetermined distance in the radial direction. In this state, the rotary table is rotated with the atmosphere inside the apparatus as a nitrogen atmosphere, and the base itself also rotates. while, by generating arc discharge between the cathode (evaporation source) and an anode electrode on both sides of the the surface of the substrate, Ti and a And then a hard coat layer of composite nitride layer of B in total average layer formed by vapor deposition with a thickness surface-coated cemented carbide cutting tools of 1 to 15 m,
In the hard coating layer, the Al highest content point and the Al lowest content point are present alternately at predetermined intervals along the layer thickness direction, and the Al lowest content point, the Al A component concentration distribution structure in which the Al content continuously changes from the lowest content point to the Al highest content point,
Furthermore, the Al highest content point, composition _{_{_{_{formula: [Ti 1- (X + Y}}}} ) Al X B Y] N ( provided that an atomic ratio, X is 0.40 to 0.60, Y is 0.01 0.10),
The Al minimum content point, composition _{_{_{_{formula: [Ti 1- (X + Y}}}} ) Al X B Y] N ( provided that an atomic ratio, X is 0.10 to 0.35, Y is from 0.01 to 0. 10),
And the interval between adjacent Al highest content point and Al lowest content point adjacent to each other is 0.01 to 0.1 μm,
A surface-coated cermet cutting tool that exhibits excellent chipping resistance under high-speed heavy cutting conditions.