JP4048365B2

JP4048365B2 - Surface coated cermet cutting tool with excellent wear resistance with hard coating layer under high speed heavy cutting conditions

Info

Publication number: JP4048365B2
Application number: JP2002301488A
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: 2002-10-16
Filing date: 2002-10-16
Publication date: 2008-02-20
Anticipated expiration: 2022-10-16
Also published as: JP2004136384A

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-(Y+Z)Ａｌ_YＢ_Z）Ｎ（ただし、原子比で、Ｙは０．４０〜０．６０、Ｚは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、上記の従来被覆サーメット工具においては、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。
【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条件で硬質被覆層がすぐれた耐摩耗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、さらに強度を有するが、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、一方側に相対的にＡｌ含有量の高いＡｌ−Ｔｉ−Ｂ合金、他方側に相対的にＴｉ含有量の高い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ＡｌとＴｉとＢの複合窒化物［以下、（Ａｌ−Ｔｉ，Ｂ）Ｎで示す］層を形成すると、この結果の（Ａｌ−Ｔｉ，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Ａｌ−Ｔｉ−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Ｔｉ含有量の高い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層厚方向にそって前記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。
【０００８】
（ｂ）上記（ａ）の繰り返し連続変化成分濃度分布構造の（Ａｌ−Ｔｉ，Ｂ）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−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−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：（Ａｌ_1-(X+Z)Ｔｉ_XＢ_Z）Ｎ（ただし、原子比で、Ｘは０．０５〜０．２５、Ｚは０．０１〜０．１０を示す）、
上記Ｔｉ最高含有点が、組成式：（Ｔｉ_1-(Y+Z)Ａｌ_YＢ_Z）Ｎ（ただし、原子比で、Ｙは０．０５〜０．２５、Ｚは０．０１〜０．１０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，Ｂ）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，Ｂ）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高強度を保持した状態で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，Ｂ）Ｎ層からなる被覆サーメット工具は、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。
【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Ａｌ−Ｔｉ−Ｂ合金、他方側にＴｉ最高含有点形成用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、（Ａｌ−Ｔｉ，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+Z)Ｔｉ_XＢ_Z）Ｎ（ただし、原子比で、Ｘは０．０５〜０．２５、Ｚは０．０１〜０．１０を示す）、
上記Ｔｉ最高含有点が、組成式：（Ｔｉ_1-(Y+Z)Ａｌ_YＢ_Z）Ｎ（ただし、原子比で、Ｙは０．０５〜０．２５、Ｚは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
硬質被覆層である（Ａｌ−Ｔｉ，Ｂ）Ｎ層のＡｌ最高含有点におけるＡｌ成分は、高温硬さと耐熱性を向上させ、同Ｔｉ成分は強度を向上させ、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成分および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、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Ｂ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０．２５を越えると、相対的にＡｌの割合が少なくなることから、高温硬さと耐熱性の低下は避けられず、これが摩耗促進の原因となり、またＢ成分の割合を示すＺ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硬さ向上効果が得られず、さらに同Ｚ値が０．１０を超えると、チッピングなどの発生原因となる強度低下が起るようになることから、Ｘ値を０．０５〜０．２５、Ｚ値を０．０１〜０．１０とそれぞれ定めた。
【００１１】
（ｂ）Ｔｉ最高含有点の組成
上記の通りＡｌ最高含有点は高温硬さと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、これによって高強度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Ｙ値がＴｉとＢの合量に占める割合（原子比）で０．２５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を確保することができず、一方同Ｙ値が同じく０．０５未満になると、相対的にＴｉの割合が多くなり過ぎて、Ｔｉ最高含有点における高温硬さと耐熱性が急激に低下し、これが摩耗促進の原因となることから、Ｙ値を０．０５〜０．２５と定めたものであり、またＢ成分の割合を示すＺ値は上記のＡｌ最高含有点におけると同じ理由で０．０１〜０．１０と定めた。
【００１２】
（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、この結果硬質被覆層に所望の高強度、さらに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。
【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リング状に装着し、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−Ｂ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−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Ｔｉ最高含有点形成用Ｔｉ−Ａｌ−Ｂ合金およびＡｌ最高含有点形成用Ａｌ−Ｔｉ−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、サーメット基体に−１００Ｖの直流バイアス電圧を印加し、前記カソード電極のＴｉ−Ａｌ−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・ＦＣ２５０の丸棒、
切削速度：４５０ｍ／ｍｉｎ．、
切り込み：４ｍｍ、
送り：０．３ｍｍ／ｒｅｖ．、
切削時間：１５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、
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：０．２ｍｍ／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、
被削材：ＪＩＳ・Ｓ５０Ｃの丸棒、
切削速度：４００ｍ／ｍｉｎ．、
切り込み：１．５ｍｍ、
送り：０．６ｍｍ／ｒｅｖ．、
切削時間：１０分、
の条件での炭素鋼の乾式連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・ＦＣ３００の丸棒、
切削速度：５００ｍ／ｍｉｎ．、
切り込み：４．５ｍｍ、
送り：０．４ｍｍ／ｒｅｖ．、
切削時間：１５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、
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：３００ｍ／ｍｉｎ．、
切り込み：４ｍｍ、
送り：０．４ｍｍ／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、
被削材：ＪＩＳ・Ｓ５５Ｃの丸棒、
切削速度：３５０ｍ／ｍｉｎ．、
切り込み：２ｍｍ、
送り：０．７ｍｍ／ｒｅｖ．、
切削時間：１０分、
の条件での炭素鋼の乾式連続高速高送り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。
【００２０】
【表１】

【００２１】
【表２】

【００２２】
【表３】

【００２３】
【表４】

【００２４】
【表５】

【００２５】
【表６】

【００２６】
【表７】

【００２７】
（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枚刃スクエアの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。
【００２８】
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。
【００２９】
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，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。
【００３０】
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・Ｓ４５Ｃの板材、
切削速度：２００ｍ／ｍｉｎ．、
溝深さ（切り込み）：１．５ｍｍ、
テーブル送り：１０００ｍｍ／分、
の条件での炭素鋼の乾式高速高送り溝切削加工試験、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・ＳＳ４００の板材、
切削速度：２５０ｍ／ｍｉｎ．、
溝深さ（切り込み）：５．５ｍｍ、
テーブル送り：１２００ｍｍ／分、
の条件での構造用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・ＳＫＤ６１の板材、
切削速度：１８０ｍ／ｍｉｎ．、
溝深さ（切り込み）：５ｍｍ、
テーブル送り：３００ｍｍ／分、
の条件での工具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９、１０にそれぞれ示した。
【００３１】
【表８】

【００３２】
【表９】

【００３３】
【表１０】

【００３４】
（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。
【００３５】
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。
【００３６】
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，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、従来被覆超硬ドリルと云う）１〜８をそれぞれ製造した。
【００３７】
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・ＳＣＭ４４０の板材、
切削速度：２００ｍ／ｍｉｎ．、
送り：０．２ｍｍ／ｒｅｖ、
穴深さ：８ｍｍ、
の条件での合金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・ＳＫＤ６１の板材、
切削速度：１６０ｍ／ｍｉｎ．、
送り：０．３ｍｍ／ｒｅｖ、
穴深さ：１６ｍｍ、
の条件での工具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・Ｓ５５Ｃの板材、
切削速度：１７５ｍ／ｍｉｎ．、
送り：０．４ｍｍ／ｒｅｖ、
穴深さ：３２ｍｍ、
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、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。
【００３８】
【表１１】

【００３９】
【表１２】

【００４０】
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Ｔｉ最高含有点の組成、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Ａｌ、Ｔｉ、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Ｔｉ最高含有点とがそれぞれ目標値と実質的に同じ組成および間隔で交互に繰り返し存在し、かつ前記Ａｌ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成分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。
【００４１】
【発明の効果】
表３〜１２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サーメット工具は、いずれも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、並びに強度不足が原因で、摩耗進行が速く、かつチッピングも発生し易いことから、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、この発明の被覆サーメット工具は、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
This invention has a high temperature hardness, heat resistance, and high strength with a hard coating layer. Therefore, cutting of various types of steel and cast iron, especially at high speed with high heat generation and high mechanical impact. A surface-coated cermet cutting tool (hereinafter referred to as a coated cermet 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 and high feed. )).
[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- (Y + Z)} Al _Y B _Z ) Ti, Al and B composite nitride satisfying N (wherein Y represents 0.40 to 0.60 and Z represents 0.01 to 0.10 in atomic ratio) [hereinafter referred to as (Ti, Al , B) A coated 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) The N layer has high-temperature hardness and heat resistance due to Al as a constituent component, and strength due to the same Ti. 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 , 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, 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 with the above-mentioned conventional coated cermet tool when it is used under normal cutting conditions. Is performed at high speed and under heavy cutting conditions such as high cutting with high mechanical impact and high feed, the high temperature hardness and heat resistance of the hard coating layer is insufficient and the strength is insufficient. Furthermore, since the progress of wear of the hard coating layer is further promoted and chipping is likely to occur, the service life is reached in a relatively short time.
[0007]
[Means for Solving the Problems]
In view of the above, the present inventors configured the above-described conventional coated cermet tool in order to develop a coated cermet tool exhibiting excellent wear resistance with a hard coating layer particularly under high-speed heavy cutting conditions. As a result of researches focusing on the hard coating layer, (a) (Ti, Al, B) N constituting a conventional coated cermet tool formed using the arc ion plating apparatus shown in FIG. The layer has a substantially uniform composition throughout the thickness of the layer, and thus has a uniform high temperature hardness, heat resistance, and strength. For example, FIG. 1 (a) is a schematic plan view, and FIG. An arc ion plating apparatus having a structure shown in a schematic front view, that is, a rotating table for mounting a cermet substrate is provided at the center of the apparatus, and Al having a relatively high Al content is placed on one side with the rotating table in between. Using an arc ion plating apparatus in which a Ti-B alloy and a Ti-Al-B alloy having a relatively high Ti content on the other side are arranged to face each other as a cathode electrode (evaporation source), the center of the apparatus on the rotary table is used. A plurality of cermet bases are mounted in a ring shape along the outer periphery of the table at a predetermined distance in the radial direction from the shaft. In this state, the rotary table is rotated while the apparatus atmosphere is a nitrogen atmosphere, and vapor deposition is performed. An arc discharge is generated between the cathode electrode (evaporation source) and the anode electrode on both sides while rotating the cermet substrate itself for the purpose of uniforming the thickness of the hard coating layer. When a composite nitride layer of Al, Ti, and B [hereinafter referred to as (Al-Ti, B) N] layer is formed, in the resulting (Al-Ti, B) N layer, When the cermet substrate arranged in a ring shape on the rolling table is closest to the cathode electrode (evaporation source) of the Al-Ti-B alloy having a relatively high Al content on one side, Al is contained in the layer. The highest content point is formed, and the highest Ti content point is formed in the layer when the cermet substrate is closest to the cathode electrode of the Ti-Al-B alloy having a relatively high Ti content on the other side. In addition, the rotation of the rotary table causes the Al highest content point and the Ti highest content point to appear alternately with a predetermined interval along the layer thickness direction in the layer, and from the Al highest content point to the Ti highest content point, It has a component concentration distribution structure in which the Al and Ti contents continuously change from the highest Ti content point to the highest Al content point.
[0008]
(B) In the formation of the (Al—Ti, B) N layer having the repeated continuous change component concentration distribution structure of (a) above, in the Al—Ti—B alloy which is the cathode electrode (evaporation source) on one side of the opposing arrangement Al content in the Ti-Al-B alloy, which is the cathode electrode (evaporation source) on the other side, with the Al content being relatively higher than the Al content of the conventional Ti-Al-B alloy. The amount is relatively low compared to the Al content of the conventional Ti-Al-B alloy, and the rotational speed of the rotary table on which the cermet substrate is mounted is controlled.
The Al maximum content point is the composition formula: (Al _{1- (X + Z)} Ti _X B _Z ) N (however, in atomic ratio, X is 0.05 to 0.25, Z is 0.01 to 0.10),
The Ti highest content point is the composition formula: (Ti _{1- (Y + Z)} Al _Y B _Z ) N (however, in atomic ratio, Y is 0.05 to 0.25, Z is 0.01 to 0.10),
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 the conventional (Ti, Al, B) N layer, it exhibits higher temperature hardness and heat resistance. In the Ti highest content point portion, since the Ti content is relatively higher than that of the conventional (Ti, Al, B) N layer, the Ti highest content point and the highest Ti content are provided. Since the interval between the contained points is extremely small, the layer as a whole has excellent high-temperature hardness and heat resistance while maintaining high strength. Therefore, the hard coating layer has such a structure (Al-Ti , B) N-layer coated cermet tools are chipped onto a hard coating layer even when various types of steel and cast iron are cut under high-speed heavy cutting conditions with high heat generation and high mechanical impact. Does not occur , To become to exert excellent wear resistance.
The research results shown in (a) and (b) above were obtained.
[0009]
This invention was made based on the above research results, A cermet substrate mounting rotary table is provided in the center of the apparatus, and the Al-Ti-B alloy for forming the highest Al content point is formed on one side, and Ti-Al-B for forming the highest Ti content point is formed on the other side across the rotary table. 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 On the surface of the cermet substrate, a hard coating layer composed of an (Al—Ti, B) N layer has an overall average layer thickness of 1 to 15 μm. Vapor deposition Coated cermet tool In ,
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,
Furthermore, the Al highest content point is the composition formula: (Al _{1- (X + Z)} Ti _X B _Z ) N (however, in atomic ratio, X is 0.05 to 0.25, Z is 0.01 to 0.10),
The Ti highest content point is the composition formula: (Ti _{1- (Y + Z)} Al _Y B _Z ) N (however, in atomic ratio, Y is 0.05 to 0.25, Z is 0.01 to 0.10),
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.
This is characterized by a coated cermet tool that exhibits excellent wear resistance under a high-speed heavy cutting condition.
[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 Al component at the highest Al content point of the (Al-Ti, B) N layer, which is a hard coating layer, improves the high temperature hardness and heat resistance, the Ti component improves the strength, and the B component further increases the high temperature hardness. Therefore, the higher the content ratio of the Al component and the B component, the higher the high temperature hardness and heat resistance, and it is suitable for high speed cutting with high heat generation, but shows the ratio of Ti. When the X value is less than 0.05 in the ratio (atomic ratio) of the total amount of Al and B, the ratio of Al becomes relatively large, and there is an adjacent Ti highest content point having high strength. However, a decrease in the strength of the layer itself is inevitable, and as a result, chipping and the like are likely to occur. On the other hand, when the X value indicating the proportion of the Ti component exceeds 0.25, the proportion of Al becomes relatively small. From high temperature hardness and reduced heat resistance This is unavoidable, this causes wear promotion, and if the Z value indicating the proportion of the B component is less than 0.01 in terms of the total amount of Al and Ti (atomic ratio), the desired high temperature hardness improving effect can be obtained. In addition, when the Z value exceeds 0.10, strength reduction that causes chipping and the like occurs, so the X value is 0.05 to 0.25, and the Z value is 0.01 to It was determined as 0.10.
[0011]
(B) Composition of the highest Ti 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. Therefore, in order to compensate for the insufficient strength of this Al highest content point, the Ti content ratio is high. Thus, the highest Ti content point that has high strength is interleaved in the thickness direction, and therefore, the Y value indicating the Al ratio in the total amount of Ti and B (atomic ratio) is 0. If it exceeds 25, the proportion of Al becomes relatively large, and the desired excellent strength cannot be ensured. On the other hand, if the Y value is also less than 0.05, the proportion of Ti is relatively large. Too much increases the high temperature hardness and heat resistance at the highest Ti content point, which causes the acceleration of wear. Therefore, the Y value is set to 0.05 to 0.25, and B The Z value indicating the proportion of the component is the Al maximum It was determined to be 0.01 to 0.10 for the same reason as in the content point.
[0012]
(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, and as a result, it is impossible to secure desired high strength, high temperature hardness and heat resistance in the hard coating layer. In addition, when the distance exceeds 0.1 μm, the disadvantages of the respective points, that is, when the Al highest content point is insufficient strength, and when the Ti highest content point is high temperature hardness and insufficient heat resistance locally in the layer. Appearance is likely to cause chipping on the cutting edge, and the progress of wear is promoted. Therefore, the interval is 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 Ti content point having various component compositions as a cathode electrode (evaporation source) mounted on the outer periphery of the table at a predetermined distance in the direction along the outer periphery of the table As the cathode electrode (evaporation source) on the other side, Al-Ti-B alloys for forming the highest Al content point with various component compositions are placed facing each other across the rotary table, and bombard cleaning metal Ti is also mounted. First, the inside of the apparatus is evacuated and kept at a vacuum of 0.5 Pa or less, and the inside of the apparatus is heated to 500 ° C. with a heater and then rotated while rotating on the rotary table. A DC bias voltage of −1000 V is applied to the cermet substrate, and an electric current of 100 A is applied between the metal Ti and anode electrode of the cathode electrode to generate an arc discharge. Nitrogen gas is introduced into the apparatus as a reaction gas to form a reaction atmosphere of 2 Pa, a DC bias voltage of −100 V is applied to the cermet substrate that rotates while rotating on the rotary table, and each cathode electrode (described above) An arc discharge is generated by flowing a current of 100 A between the anode electrode and a Ti-Al-B alloy for forming the highest Ti content point and an Al-Ti-B alloy for forming the highest Al content point. On the surface, the highest Al content point and the highest Ti content point of the target composition shown in Tables 3 and 4 intersect along the layer thickness direction. Similarly, the Al and Ti contents are repeatedly present at the target intervals shown in Tables 3 and 4, and the Al and Ti content points from the Al highest content point to the Ti highest content point and the Ti highest content point to the Al highest content point, respectively. The surface coated cermet throwaway of the present invention as a coated cermet tool of the present invention by vapor-depositing a hard coating layer having a component concentration distribution structure that varies with time and having a target total layer thickness also shown in Tables 3 and 4 Chips (hereinafter referred to as the present invention-coated chips) 1 to 16 were produced.
[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. Equipped with Ti-Al-B alloy with various component composition as cathode electrode (evaporation source), and also with metallic Ti for bombard cleaning, first evacuates the apparatus and keeps it at a vacuum of 0.5 Pa or less Then, after heating the inside of the apparatus to 500 ° C. with a heater, a DC bias voltage of −1000 V was applied to the cermet base, and a current of 100 A was passed between the metal Ti of the cathode electrode and the anode electrode to generate an arc. A discharge was generated, and the surface of the cermet substrate was cleaned by Ti bombardment. Then, nitrogen gas was introduced into the apparatus as a reaction gas, and the reaction atmosphere was 2 Pa. At the same time, a DC bias voltage of −100 V is applied to the cermet substrate, and a current of 100 A is passed between the Ti—Al—B alloy of the cathode electrode and the anode electrode to generate an arc discharge, whereby the cermet substrate A1. The target compositions and target layer thicknesses shown in Tables 5 and 6 are provided on the surfaces of .about.A10 and B1 to B6, and there is substantially no change in composition along the layer thickness direction (Ti, Al, B). By vapor-depositing a hard coating layer composed of an N layer, conventional surface-coated cermet throwaway tips (hereinafter referred to as conventional coated chips) 1 to 16 as conventional coated cermet tools were produced.
[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 / FC250 round bar,
Cutting speed: 450 m / min. ,
Incision: 4mm,
Feed: 0.3 mm / rev. ,
Cutting time: 15 minutes,
Dry continuous high-speed high-cut 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: 0.2 mm / rev. ,
Cutting time: 5 minutes
Dry interrupted high-speed high-cut cutting test of alloy steel under the conditions of
Work material: JIS / S50C round bar,
Cutting speed: 400 m / min. ,
Incision: 1.5mm,
Feed: 0.6 mm / rev. ,
Cutting time: 10 minutes,
A dry continuous high-speed high-feed cutting test of carbon 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 / FC300 round bar,
Cutting speed: 500 m / min. ,
Cutting depth: 4.5mm,
Feed: 0.4 mm / rev. ,
Cutting time: 15 minutes,
Dry continuous high-speed high-cut cutting test of cast iron under the conditions of
Work material: JIS · SCM435 lengthwise equally spaced four round grooved round bars,
Cutting speed: 300 m / min. ,
Incision: 4mm,
Feed: 0.4 mm / rev. ,
Cutting time: 5 minutes
Dry interrupted high-speed high-cut cutting test of alloy steel under the conditions of
Work material: JIS / S55C round bar,
Cutting speed: 350 m / min. ,
Cutting depth: 2mm,
Feed: 0.7 mm / rev. ,
Cutting time: 10 minutes,
The dry continuous high-speed, high-feed cutting test of carbon 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 Table 7.
[0020]
[Table 1]

[0021]
[Table 2]

[0022]
[Table 3]

[0023]
[Table 4]

[0024]
[Table 5]

[0025]
[Table 6]

[0026]
[Table 7]

[0027]
(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 a powder, a 1.5 μm VC powder, a 1.0 μm (Ti, W) C powder, and a 1.8 μm Co powder, and blend these raw material powders into the composition shown in Table 8. 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 kinds of round bar sintered bodies for forming a cermet substrate were formed, and the above three kinds of round bar sintered bodies were subjected to grinding and combined in the combinations shown in Table 8 to obtain the diameter of the cutting edge portion × Each length is 6mm × 13mm, 10mm × 22mm And dimensions of 20 mm × 45 mm, as well as any twist angle of 30 degrees 4 flute square shape cermet substrate (end mill) C-1 through C-8 with a prepared, respectively.
[0028]
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 highest Ti content point of the target composition shown in Table 9 along the layer thickness direction alternately and repeatedly exist at the target interval shown in Table 9, and the Al It has a component concentration distribution structure in which the Al and Ti contents continuously change from the highest content point to the Ti highest content point, and from the Ti highest content point to the Al highest content point, and is also shown in Table 9 By vapor-depositing a hard coating layer having a total thickness, each of the surface coated cermet end mills (hereinafter referred to as the present coated end mills) 1 to 8 as the present coated cermet tool is provided. And elephants.
[0029]
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 10 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.
[0030]
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 / S45C plate,
Cutting speed: 200 m / min. ,
Groove depth (cut): 1.5 mm,
Table feed: 1000 mm / min,
With respect to the dry high speed high feed groove cutting test of carbon steel under the conditions of the present invention, the present coated end mills 4 to 6 and the conventional coated end mills 4 to 6,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / SS400 plate material,
Cutting speed: 250 m / min. ,
Groove depth (cut): 5.5 mm,
Table feed: 1200mm / min,
With respect to the dry high-speed, high-cut groove cutting test of structural steel under the conditions of
Work material: Plane dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SKD61 plate material,
Cutting speed: 180 m / min. ,
Groove depth (cut): 5 mm,
Table feed: 300mm / min,
Each of the dry high-speed high-feed grooving test of the tool steel under the above conditions was conducted, and in each grooving test, 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 The cutting groove length up to was measured. The measurement results are shown in Tables 9 and 10, respectively.
[0031]
[Table 8]

[0032]
[Table 9]

[0033]
[Table 10]

[0034]
(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 bases D-4 to D-6), and 16 mm × 45 mm (cermet bases D-7 and D-8), and 2 with a twist angle of 30 degrees. Cermet substrates (drills) D-1 to D-8 having a single blade shape were produced.
[0035]
Next, the cutting blades of these cermet bases (drills) D-1 to D-8 are subjected to honing, ultrasonically cleaned in acetone, and dried in the arc ion plating apparatus shown in FIG. In the same conditions as in Example 1 above, the highest Al content point and the highest Ti content point of the target composition shown in Table 11 along the layer thickness direction alternately at the target interval shown in Table 11 It has a component concentration distribution structure that repeatedly exists and the 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, and Similarly, by depositing a hard coating layer having a target total layer thickness shown in Table 11, the surface-coated cermet drill of the present invention as the coated cermet tool of the present invention (hereinafter referred to as the present coated drill). 1 to 8 were prepared, respectively.
[0036]
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 12 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 carbide drills) 1 to 8 as conventional coated cermet tools were produced, respectively. .
[0037]
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 / SCM440 plate material,
Cutting speed: 200 m / min. ,
Feed: 0.2mm / rev,
Hole depth: 8mm,
For the wet high-speed high-feed drilling test of alloy 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 dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SKD61 plate material,
Cutting speed: 160 m / min. ,
Feed: 0.3mm / rev,
Hole depth: 16mm,
With respect to the tool steel wet high-speed high-feed drilling test, the present invention coated drills 7 and 8 and the conventional coated drills 7 and 8,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / S55C plate material,
Cutting speed: 175 m / min. ,
Feed: 0.4mm / rev,
Hole depth: 32mm,
Wet high-speed high-feed drilling test of carbon steel under the above conditions, and the flank wear width of the cutting edge surface reaches 0.3 mm in any wet drilling test (using water-soluble cutting oil) The number of drilling processes up to was measured. The measurement results are shown in Tables 11 and 12, respectively.
[0038]
[Table 11]

[0039]
[Table 12]

[0040]
The highest Al content point and the highest Ti in the hard coating layers constituting the coated chips 1-16, the coated end mills 1-8, and the coated drills 1-8 as the coated cermet tools of the present invention obtained as a result. About the composition of the content points 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, Al, Ti, and When the content of B was measured using an Auger spectroscopic analyzer, in the hard coating layer of the coated cermet tool of the present invention, the highest Al content point and the highest Ti content point had the same composition and spacing as the target values, respectively. Al and Ti components are alternately present and from the highest Al content point to the highest Ti content point, from the highest Ti content point to the highest Al content point. Content is confirmed to have each continuously 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.
[0041]
【The invention's effect】
From the results shown in Tables 3 to 12, the hard coating layer has an Al highest content point having excellent high temperature hardness and heat resistance and a Ti highest content point having high strength at predetermined intervals alternately in the layer thickness direction. The present invention has a component concentration distribution structure that repeatedly exists and 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. Coated cermet tools are all capable of cutting various types of steel and cast iron under high speed conditions with high temperature generation and heavy cutting conditions such as high cutting and high feed with high mechanical impact. While the hard coating layer exhibits excellent wear resistance without occurrence of chipping, the hard coating layer is composed of a (Ti, Al, B) N layer having substantially no composition change along the layer thickness direction. Conventional coating In a metal tool, the high-speed heavy cutting conditions are relatively short because wear progresses quickly and chipping easily occurs due to high-temperature hardness and insufficient heat resistance and insufficient strength of the hard coating layer. It is clear that the service life is reached in time.
As described above, the coated cermet tool according to the present invention can be used not only for cutting under normal conditions, but also for cutting various steels and cast irons under high-speed heavy cutting conditions with high heat generation and high mechanical impact. In this case, since chipping does not occur and excellent wear resistance is exhibited, it is possible to satisfactorily cope with labor saving and energy saving of cutting 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 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 at the center of the apparatus, and Al— Using an arc ion plating apparatus in which a Ti-B alloy and a Ti-Al-B alloy for forming the highest Ti 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 substrates 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 rotating table is rotated with the atmosphere inside the apparatus as a nitrogen atmosphere, and the substrate itself also rotates. Then, an arc discharge is generated between the cathode electrode (evaporation source) and the anode electrode on both sides, and Al and T are formed on the surface of the substrate. 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 cermet cutting tool 1 to 15 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,
Furthermore, the Al highest content point, composition _{_{_{_{formula: [Al 1- (X + Z}}}} ) Ti X B Z] N ( provided that an atomic ratio, X is 0.05 to 0.25, Z is 0.01 0.10),
The Ti maximum content point, composition _{_{_{_{formula: [Ti 1- (Y + Z}}}} ) Al Y B Z] N ( provided that an atomic ratio, Y is 0.05 to 0.25, Z is from 0.01 to 0. 10),
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 cermet cutting tool that exhibits excellent wear resistance with a hard coating layer under high-speed heavy cutting conditions.