JP4029329B2

JP4029329B2 - Surface coated cermet cutting tool with excellent wear resistance with high hard coating layer in high speed cutting

Info

Publication number: JP4029329B2
Application number: JP2002300335A
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: JP2004130496A

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特性を有し、したがって特に各種の鋼や鋳鉄などの高熱発生を伴う高速切削加工で、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、前記被削材の穴あけ切削加工などに用いられるドリルやミニチュアドリル、さらに前記被削材の面削加工や溝加工、肩加工などに用いられるソリッドタイプのエンドミルなどがあり、また前記スローアウエイチップを着脱自在に取り付けて前記ソリッドタイプのエンドミルと同様に切削加工を行うスローアウエイエンドミル工具などが知られている。
【０００３】
また、被覆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：（Ａｌ_1-(X+Y)Ｔｉ_XＢ_Y）Ｎ（ただし、原子比で、Ｘは０．３５〜０．５５、Ｙ：０．０１〜０．１０を示す）を満足するＡｌとＴｉとＢの複合窒化物［以下、（Ａｌ，Ｔｉ，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（Ａｌ，Ｔｉ，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Ａｌ−Ｔｉ−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（Ａｌ，Ｔｉ，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、切削加工は高速化の傾向にあるが、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、これを高い発熱を伴う高速切削条件で用いた場合には、硬質被覆層が高強度と高靭性を具備するものの、高温硬さおよび耐熱性が不十分であるため、硬質被覆層の摩耗進行が促進され、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、特に高速切削加工で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（Ａｌ，Ｔｉ，Ｂ）Ｎからなる硬質被覆層は、層厚全体に亘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（Ａｌ，Ｔｉ，Ｂ）Ｎ層の形成にカソード電極（蒸発源）として用いられたＡｌ−Ｔｉ−Ｂ合金に相当する相対的にＴｉ含有量の高いＡｌ−Ｔｉ−Ｂ合金、他方側に相対的にＴｉ含有量の低いＡｌ−Ｔｉ−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，Ｔｉ，Ｂ）Ｎ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Ｔｉ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Ｔｉ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含有量の低いＡｌ−Ｔｉ−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Ｔｉ最高含有点とＴｉ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Ｔｉ最高含有点から前記Ｔｉ最低含有点、前記Ｔｉ最低含有点から前記Ｔｉ最高含有点へＴｉ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（Ａｌ，Ｔｉ，Ｂ）Ｎ層において、例えば対向配置のカソード電極（蒸発源）のそれぞれの組成を調製すると共に、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Ｔｉ最高含有点が、組成式：（Ａｌ_1-(X+Y)Ｔｉ_XＢ_Y）Ｎ（ただし、原子比で、Ｘは０．３５〜０．５５、Ｙ：０．０１〜０．１０を示す）、
上記Ｔｉ最低含有点が、組成式：（Ａｌ_1-(X+Y)Ｔｉ_XＢ_Y）Ｎ（ただし、原子比で、Ｘは０．０５〜０．２５、Ｙ：０．０１〜０．１０を示す）、
をそれぞれ満足し、かつ隣り合う上記Ｔｉ最高含有点とＴｉ最低含有点の厚さ方向の間隔を０．０１〜０．１μmとすると、
上記Ｔｉ最低含有点部分では、上記の従来（Ａｌ，Ｔｉ，Ｂ）Ｎ層に比してＡｌ含有量が相対的に高くなることから、Ｂ成分による高温硬さ向上効果と相俟って、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最高含有点部分は、前記従来（Ａｌ，Ｔｉ，Ｂ）Ｎ層と同等の組成、すなわち前記Ｔｉ最低含有点部分に比して相対的にＡｌ含有量が低く、Ｔｉ含有量の高い組成をもつので、高強度を保持し、かつこれらＴｉ最高含有点とＴｉ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、高い発熱を伴う鋼や鋳鉄などの高速切削加工で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Ｔｉ最高含有点形成用Ａｌ−Ｔｉ−Ｂ合金、他方側にＴｉ最低含有点形成用Ａｌ―Ｔｉ−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おいて、
上記硬質被覆層が、層厚方向にそって、Ｔｉ最高含有点とＴｉ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Ｔｉ最高含有点から前記Ｔｉ最低含有点、前記Ｔｉ最低含有点から前記Ｔｉ最高含有点へＴｉ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Ｔｉ成分最高含有点が、組成式：（Ａｌ_1-(X+Y)Ｔｉ_XＢ_Y）Ｎ（ただし、原子比で、Ｘは０．３５〜０．５５、Ｙ：０．０１〜０．１０を示す）、
上記Ｔｉ成分最低含有点が、組成式：（Ａｌ_1-(X+Y)Ｔｉ_XＢ_Y）Ｎ（ただし、原子比で、Ｘは０．０５〜０．２５、Ｙ：０．０１〜０．１０を示す）、
を満足し、かつ隣り合う上記Ｔｉ最高含有点とＴｉ最低含有点の間隔が、０．０１〜０．１μmである、
高速切削加工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）Ｔｉ最低含有点の組成
Ｔｉ最低含有点の（Ａｌ，Ｔｉ，Ｂ）Ｎにおける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、一方同Ｔｉ成分には、強度を向上させる作用があるので、前記Ｔｉ最低含有点では相対的にＴｉ含有量を低くし、Ａｌ含有量を高くして、高熱発生を伴う高速切削に適応するすぐれた高温硬さと耐熱性を具備せしめたものであるが、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の低下は避けられず、この結果チッピングなどが発生し易くなり、一方Ｔｉの割合を示すＸ値が同０．２５を越えると、相対的にＡｌの割合が少なくなり過ぎて、高速切削に要求されるすぐれた高温硬さと耐熱性を確保することができなくなるものであり、またＢの割合を示すＹ値がＡｌとＴｉの合量に占める割合（原子比）で０．０１未満では所望の高温硬さ向上効果が得られず、さらに同Ｘ値が０．１０を超えると、強度が急激に低下するようになることから、Ｘ値を０．０５〜０．２５、Ｙ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Ｔｉ最低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Ｔｉ最低含有点の強度不足を補う目的で、上記の従来（Ａｌ，Ｔｉ，Ｂ）Ｎ層と同等の組成、すなわち相対的に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Ｔｉの割合を示すＸ値がＡｌおよびＢ成分との合量に占める割合（原子比）で０．３５未満では、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０．５５を越えると、Ａｌに対するＴｉの割合が多くなり過ぎて、Ｔｉ最高含有点の高温硬さと耐熱性が不十分となり、摩耗促進の原因となることから、Ｔｉ最高含有点でのＴｉの割合を示すＸ値を０．３５〜０．５５と定めた。
また、Ｔｉ最高含有点におけるＢ成分は、上記の通りＡｌ成分との共存で高温硬さを一段と向上させ、高熱発生を伴う高速切削で有用な効果を発揮するものであり、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Ｔｉ最高含有点での強度に低下傾向が現れるようになることから、Ｙ値を０．０１〜０．１０と定めた。
【００１２】
（ｃ）Ｔｉ最低含有点と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温硬さと耐熱性、および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Ｔｉ最低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、切刃にチッピングが発生し易くなることから、その平均層厚を１〜１５μｍと定めた。
【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、ＺｒＣ粉末、ＶＣ粉末、ＴａＣ粉末、ＮｂＣ粉末、Ｃr₃Ｃ₂粉末、ＴｉＮ粉末、ＴａＮ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外周部にそって装着し、一方側のカソード電極（蒸発源）として、種々の成分組成をもったＴｉ最低含有点形成用Ａｌ−Ｔｉ−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Ｔｉ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最低含有点形成用Ａｌ−Ｔｉ−Ｂ合金およびＴｉ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Ｔｉ最低含有点と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Ｔｉ最高含有点から前記Ｔｉ最低含有点、前記Ｔｉ最低含有点から前記Ｔｉ最高含有点へＴｉ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Ａｌ−Ｔｉ−Ｂ合金を装着し、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（Ａｌ，Ｔｉ，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・ＳＮＣＭ４３９の丸棒、
切削速度：４５０ｍ／ｍｉｎ．、
切り込み：２．５ｍｍ、
送り：０．３５ｍｍ／ｒｅｖ．、
切削時間：１０分、
の条件での合金鋼の乾式連続高速切削加工試験、
被削材：ＪＩＳ・Ｓ５０Ｃの長さ方向等間隔４本縦溝入り丸棒、
切削速度：３５０ｍ／ｍｉｎ．、
切り込み：２ｍｍ、
送り：０．３５ｍｍ／ｒｅｖ．、
切削時間：５分、
の条件での炭素鋼の乾式断続高速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・ＳＣＭ４４０の丸棒、
切削速度：５００ｍ／ｍｉｎ．、
切り込み：２．５ｍｍ、
送り：０．３ｍｍ／ｒｅｖ．、
切削時間：１０分、
の条件での合金鋼の乾式連続高速切削加工試験、
被削材：ＪＩＳ・Ｓ５５Ｃの長さ方向等間隔４本縦溝入り丸棒、
切削速度：４００ｍ／ｍｉｎ．、
切り込み：２ｍｍ、
送り：０．３ｍｍ／ｒｅｖ．、
切削時間：５分、
の条件での炭素鋼の乾式断続高速切削加工試験を行い、いずれの切削加工試験でも切刃の逃げ面摩耗幅を測定した。この測定結果を表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の表面をアセトン中で超音波洗浄し、乾燥した状態で、同じく図１に示されるアークイオンプレーティング装置に装入し、上記実施例１と同一の条件で、層厚方向に沿って表９に示される目標組成のＴｉ最低含有点と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Ｔｉ最高含有点から前記Ｔｉ最低含有点、前記Ｔｉ最低含有点から前記Ｔｉ最高含有点へＴｉ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の表面をアセトン中で超音波洗浄し、乾燥した状態で、同じく図２に示される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（Ａｌ，Ｔｉ，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・ＳＫＤ６１の板材、
切削速度：２００ｍ／ｍｉｎ．、
溝深さ（切り込み）：０．１ｍｍ、
テーブル送り：１０００ｍｍ／分、
の条件での焼き入れ鋼の乾式高速溝切削加工試験、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・ＳＣＭ４３５の板材、
切削速度：３００ｍ／ｍｉｎ．、
溝深さ（切り込み）：１ｍｍ、
テーブル送り：８００ｍｍ／分、
の条件での合金鋼の乾式高速溝切削加工試験、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・ＦＣ２５０の板材、
切削速度：２５０ｍ／ｍｉｎ．、
溝深さ（切り込み）：４．５ｍｍ、
テーブル送り：５００ｍｍ／分、
の条件での鋳鉄の乾式高速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Ｔｉ最低含有点と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Ｔｉ最高含有点から前記Ｔｉ最低含有点、前記Ｔｉ最低含有点から前記Ｔｉ最高含有点へＴｉ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（Ａｌ，Ｔｉ，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。
【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×２５０、厚さ：５０ｍｍのＪＩＳ・ＳＳ４００の板材、
切削速度：１５０ｍ／ｍｉｎ．、
送り：０．１８ｍｍ／ｒｅｖ、
穴深さ：８ｍｍ、
の条件での構造用鋼の湿式高速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・Ｓ５０Ｃの板材、
切削速度：１２０ｍ／ｍｉｎ．、
送り：０．２３ｍｍ／ｒｅｖ、
穴深さ：１６ｍｍ、
の条件での炭素鋼の湿式高速穴あけ切削加工試験、本発明被覆ドリル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・ＳＣＭ４２０の板材、
切削速度：７０ｍ／ｍｉｎ．、
送り：０．２３ｍｍ／ｒｅｖ、
穴深さ：３２ｍｍ、
の条件での合金鋼の湿式高速穴あけ切削加工試験、をそれぞれ行い、いずれの湿式高速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Ｔｉ最高含有点とＴｉ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、Ｔｉ最高含有点とＴｉ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Ｔｉ最高含有点から前記Ｔｉ最低含有点、前記Ｔｉ最低含有点から前記Ｔｉ最高含有点へＴｉ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。
【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Ｔｉ最低含有点と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Ｔｉ最高含有点から前記Ｔｉ最低含有点、前記Ｔｉ最低含有点から前記Ｔｉ最高含有点へＴｉ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、いずれも鋼や鋳鉄の切削加工を高い発熱を伴う高速で行っても、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（Ａｌ，Ｔｉ，Ｂ）Ｎ層からなる従来被覆サーメット工具においては、高温を伴う高速切削加工では高温硬さと耐熱性不足が原因で切刃の摩耗進行が速く、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、特に各種の鋼や鋳鉄などの高速切削加工でもすぐれた耐摩耗性を発揮し、長期に亘ってすぐれた切削性能を示すものであるから、切削加工装置の高性能化、並びに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 characteristic with a hard coating layer, and therefore, a surface-coated cermet cutting tool (hereinafter referred to as “high wear resistance”), particularly in high-speed cutting with high heat generation such as various steels and cast iron , Referred to as a coated cermet tool).
[0002]
[Prior art]
In general, for coated cermet tools, a throw-away tip that is attached to the tip of a bite for use in turning and planing of various steel and cast iron work materials, and drilling of the work material. Drills and miniature drills, etc., and also solid type end mills used for chamfering, grooving, shoulder processing, etc. of the work material, and the solid type by attaching the throwaway tip detachably A slow-away end mill tool that performs a cutting process in the same manner as an end mill is known.
[0003]
Further, as a coated cermet tool, a composition formula (Al) is formed on the surface of a cermet substrate made of tungsten carbide (hereinafter referred to as WC) -based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) -based cermet. _{1- (X + Y)} Ti _X B _Y ) A composite nitride of Al, Ti and B satisfying N (wherein X represents 0.35 to 0.55, Y: 0.01 to 0.10 in atomic ratio) [hereinafter referred to as (Al, Ti , B) N] is known, and a coated cermet tool obtained by physically vapor-depositing a hard coating layer having a layer thickness of 1 to 15 μm is known, and (Al, Ti, B) N of the coated cermet tool is known. The layer has high-temperature hardness and heat resistance by Al as a constituent component, strength by Ti, and combined with the effect of improving the high-temperature hardness by the same B, this is continuous with various steels and cast irons. It is also known to exhibit excellent cutting performance when used for cutting and intermittent cutting (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 the cathode electrode (evaporation source) in which an Al—Ti—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 2 Pa, for example. On the other hand, the cermet substrate is subjected to the above (Al , Ti, 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, while on the other hand, there is a strong demand for labor saving, energy saving, and cost reduction for cutting, and with this, cutting tends to be faster. In a coated cermet tool, there is no problem when it is used under normal cutting conditions, but when it is used under high-speed cutting conditions with high heat generation, the hard coating layer has high strength and high toughness. Although it is provided, since the high temperature hardness and heat resistance are insufficient, the progress of wear of the hard coating layer is promoted and the service life is reached in a relatively short time.
[0007]
[Means for Solving the Problems]
In view of the above, the present inventors have focused on the hard coating layer constituting the conventional coated cermet tool in order to develop a coated cermet tool that exhibits excellent wear resistance particularly in high-speed cutting. As a result of research,
(A) The hard coating layer made of (Al, Ti, B) N constituting the conventional coated cermet tool formed by using the arc ion plating apparatus shown in FIG. 2 is homogeneous throughout the layer thickness. The arc ion plating apparatus having the structure shown in FIG. 1A is a schematic plan view and FIG. 1B is a schematic front view, that is, a cermet at the center of the apparatus. An Al-Ti-B alloy used as a cathode electrode (evaporation source) for forming the above-described conventional (Al, Ti, B) N layer on one side across the turntable is provided. Arc ions in which the corresponding Al-Ti-B alloy having a relatively high Ti content and the Al-Ti-B alloy having a relatively low Ti content are arranged opposite to each other as a cathode electrode (evaporation source) on the other side Using a rating device, a plurality of cermet bases are mounted in a ring shape along the outer periphery at a predetermined distance in the radial direction from the central axis on the rotary table of the device. In this state, the atmosphere in the device is a nitrogen atmosphere. As the rotating table is rotated and the cermet substrate itself is rotated for the purpose of uniforming the thickness of the hard coating layer formed by vapor deposition, the cathode electrode (evaporation source) on both sides is interposed between the anode electrode and the anode electrode. When an arc discharge is generated to form an (Al, Ti, B) N layer on the surface of the cermet substrate, the resulting (Al, Ti, B) N layer is arranged in a ring shape on the rotary table. Further, when the cermet substrate is closest to the cathode electrode (evaporation source) of the Al—Ti—B alloy having a relatively high Ti content on one side, the highest Ti in the layer is obtained. A point is formed, and when the cermet substrate is closest to the cathode electrode of the relatively low Ti content Al-Ti-B alloy on the other side, the lowest Ti content point is formed in the layer. By rotating the turntable, the highest Ti content point and the lowest Ti content point appear alternately in the layer thickness direction in the layer, and the Ti lowest content point, the Ti lowest content point, It has a component concentration distribution structure in which the Ti content continuously changes from the content point to the Ti highest content point.
[0008]
(B) In the (Al, Ti, B) N layer having the repeated continuous change component concentration distribution structure of (a) above, for example, the respective compositions of the cathode electrodes (evaporation sources) arranged opposite to each other are prepared, and the cermet substrate is attached. Control the rotation speed of the rotating table,
The Ti highest content point is the composition formula: (Al _{1- (X + Y)} Ti _X B _Y ) N (however, in terms of atomic ratio, X represents 0.35 to 0.55, Y represents 0.01 to 0.10),
The minimum Ti content point is the composition formula: (Al _{1- (X + Y)} Ti _X B _Y ) N (however, in terms of atomic ratio, X represents 0.05 to 0.25, Y represents 0.01 to 0.10),
And the distance between the adjacent Ti highest content point and Ti lowest content point in the thickness direction is 0.01 to 0.1 μm,
In the Ti minimum content point portion, since the Al content is relatively higher than the conventional (Al, Ti, B) N layer, combined with the high temperature hardness improvement effect by the B component, More excellent high temperature hardness and heat resistance, while the highest Ti content point portion has the same composition as the conventional (Al, Ti, B) N layer, that is, relative to the lowest Ti content point portion. Since it has a low Al content and a high Ti content, it maintains high strength and the distance between the highest Ti content point and the lowest Ti content point is extremely small. Therefore, the coated cermet tool composed of the (Al, Ti, B) N layer with the hard coating layer is made of steel with high heat generation, For high speed cutting such as cast iron To become possible to exert abrasion resistance gray.
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 Ti—highest content point forming Al—Ti—B alloy on one side and the Ti lower content point forming Al—Ti—B 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 is formed with an overall average layer thickness of 1 to 15 μm. Vapor deposition In the coated cermet tool,
In the hard coating layer, the highest Ti content point and the lowest Ti content point are alternately present at predetermined intervals along the thickness direction, and the lowest Ti content point, the Ti content from the highest Ti content point, A component concentration distribution structure in which the Ti content continuously changes from the lowest content point to the Ti highest content point,
Further, the highest Ti component content point is the composition formula: (Al _{1- (X + Y)} Ti _X B _Y ) N (however, in terms of atomic ratio, X represents 0.35 to 0.55, Y represents 0.01 to 0.10),
The Ti component minimum content point is the composition formula: (Al _{1- (X + Y)} Ti _X B _Y ) N (however, in terms of atomic ratio, X represents 0.05 to 0.25, Y represents 0.01 to 0.10),
And the interval between the adjacent highest Ti content point and the lowest Ti content point is 0.01 to 0.1 μm.
It is characterized by a coated cermet tool that exhibits excellent wear resistance with a hard coating layer in high-speed cutting.
[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 lowest Ti content point
The Al component in (Al, Ti, B) N at the lowest Ti content point improves the high-temperature hardness and heat resistance, and the B component further improves the high-temperature hardness, while the Ti component improves the strength. Therefore, the Ti content is relatively low at the Ti minimum content point, and the Al content is increased to provide excellent high-temperature hardness and heat resistance suitable for high-speed cutting with high heat generation. However, when the X value indicating the proportion of Ti is less than 0.05 in terms of the total amount of Al and B (atomic ratio), the proportion of Al is relatively large and the strength is high. Even if the highest Ti content point is present adjacently, a decrease in the strength of the layer itself is unavoidable, and as a result, chipping and the like are likely to occur, while when the X value indicating the ratio of Ti exceeds 0.25, Since the proportion of Al is relatively low, The excellent high-temperature hardness and heat resistance required for the material cannot be ensured, and the Y value indicating the ratio of B is less than 0.01 in terms of the total amount of Al and Ti (atomic ratio). If the desired high-temperature hardness improvement effect cannot be obtained, and the X value exceeds 0.10, the strength decreases rapidly, so the X value is 0.05 to 0.25, and the Y value is It was determined as 0.01 to 0.10, respectively.
[0011]
(B) Composition of the highest Ti content point
As described above, the Ti minimum content point is excellent in high-temperature hardness and heat resistance, but on the other hand, the strength is inferior. Therefore, in order to compensate for the insufficient strength of the Ti minimum content point, the conventional (Al, Ti B) Composition equivalent to that of the N layer, that is, the Ti content is relatively high, while the Al content is low, whereby the highest Ti content points that have high strength are alternately interposed in the thickness direction. Therefore, if the X value indicating the proportion of Ti is less than 0.35 in terms of the total amount of Al and B components (atomic ratio), the desired excellent strength cannot be ensured, while the X If the value exceeds 0.55, the ratio of Ti to Al increases too much, resulting in insufficient high-temperature hardness and heat resistance at the highest Ti content point, which causes accelerated wear. The X value indicating the proportion of Ti is set to 0. It was defined as 5 to 0.55.
In addition, the B component at the highest Ti content point improves the high-temperature hardness by coexistence with the Al component as described above, and exhibits a useful effect in high-speed cutting with high heat generation. Therefore, the Y value is 0. If it is less than 0.01, the desired high temperature hardness improvement effect cannot be obtained. On the other hand, if the Y value exceeds 0.10, the strength at the highest Ti content point tends to decrease. ~ 0.10.
[0012]
(C) Interval between the lowest Ti 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 ensure the desired high temperature hardness and heat resistance, and strength to the hard coating layer, Further, when the distance exceeds 0.1 μm, the disadvantages of each point, that is, insufficient strength at the lowest Ti content point, insufficient high temperature hardness and insufficient heat resistance at the highest Ti content point, appear locally in the layer. Because of this, chipping is likely to occur on the cutting edge, 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 at the cutting edge. It was defined as ˜15 μm.
[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
As raw material powders, WC powder, TiC powder, ZrC powder, VC powder, TaC powder, NbC powder, Cr, all having an average particle diameter of 1 to 3 μm. _Three C ₂ Powder, TiN powder, TaN powder, and Co powder are prepared. These raw material powders are blended in the blending composition shown in Table 1, wet-mixed by a ball mill for 72 hours, dried, and then compacted at a pressure of 100 MPa. The green compact was sintered in a vacuum of 6 Pa at a temperature of 1400 ° C. for 1 hour. After sintering, the cutting edge portion was subjected to a honing process of R: 0.03 and ISO Cermet bases A1 to A10 made of WC-base cemented carbide having a standard / CNMG120408 chip shape 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. Attached along the outer periphery at a position separated by a predetermined distance in the direction, as a cathode electrode (evaporation source) on one side, an Al—Ti—B alloy for forming a Ti minimum content point having various component compositions, on the other side As a cathode electrode (evaporation source), an Al-Ti-B alloy for forming the highest Ti content point having various component compositions is arranged opposite to each other with the rotary table interposed therebetween, and a bombard cleaning metal Ti is also mounted. The inside of the apparatus is heated to 500 ° C. with a heater while the interior is evacuated and kept at a vacuum of 0.5 Pa or less, and then the cermet substrate that rotates while rotating on the rotary table is − A DC bias voltage of 000 V is applied, and a current of 100 A is passed between the metal Ti and the anode electrode of the cathode electrode to generate an arc discharge, thereby cleaning the surface of the cermet substrate by Ti bombardment and then reacting in the apparatus. Nitrogen gas was introduced as a gas to make 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 (the lowest Ti content point) An Al-Ti-B alloy for forming and an Al-Ti-B alloy for forming the highest Ti content point) and an anode electrode to generate an arc discharge, and a layer is formed on the surface of the cermet substrate. The Ti minimum content point and the Ti maximum content point of the target composition shown in Tables 3 and 4 along the thickness direction alternately in Tables 3 and 4 It has a component concentration distribution structure that repeatedly exists at the indicated target intervals and in which the Ti content continuously changes from the Ti highest content point to the Ti lowest content point and from the Ti lowest content point to the Ti highest content point. In addition, by depositing a hard coating layer having a target total layer thickness shown in Tables 3 and 4, a throwaway tip made of the surface-coated cermet of the present invention as the coated cermet tool of the present invention (hereinafter referred to as the present coated chip) 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. The cathode electrode (evaporation source) is equipped with Al-Ti-B alloys with various component compositions, and bombard cleaning metal Ti is also installed. First, the inside of the apparatus is evacuated and kept 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 is generated, and the surface of the cermet substrate is cleaned by Ti bombardment. Then, nitrogen gas is introduced into the apparatus as a reaction gas to form a reaction atmosphere of 2 Pa. At the same time, 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 on the respective surfaces of the cermet substrates A1 to A10 and B1 to B6. And depositing a hard coating layer composed of an (Al, Ti, B) N layer having the target composition and the target layer thickness shown in Tables 5 and 6 and substantially no composition change along the layer thickness direction. Thus, 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 / SNCM439 round bar,
Cutting speed: 450 m / min. ,
Incision: 2.5mm,
Feed: 0.35 mm / rev. ,
Cutting time: 10 minutes,
Dry continuous high speed cutting test of alloy steel under the conditions of
Work material: JIS / S50C lengthwise equal 4 round grooved round bars,
Cutting speed: 350 m / min. ,
Cutting depth: 2mm,
Feed: 0.35 mm / rev. ,
Cutting time: 5 minutes
The carbon steel was subjected to a dry intermittent high-speed cutting test under the following conditions.
[0019]
Furthermore, for the present coated chips 11-16 and the conventional coated chips 11-16,
Work material: JIS / SCM440 round bar,
Cutting speed: 500 m / min. ,
Incision: 2.5mm,
Feed: 0.3 mm / rev. ,
Cutting time: 10 minutes,
Dry continuous high speed cutting test of alloy steel under the conditions of
Work material: JIS / S55C lengthwise equidistant round bars with 4 vertical grooves,
Cutting speed: 400 m / min. ,
Cutting depth: 2mm,
Feed: 0.3 mm / rev. ,
Cutting time: 5 minutes
The carbon steel was subjected to a dry intermittent high-speed cutting test under the above conditions, and the flank wear width of the cutting edge was measured in any of the cutting tests. 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]
Next, the surfaces of 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. Under the same conditions as in Example 1, the Ti lowest content point and the Ti highest content point of the target composition shown in Table 9 along the layer thickness direction are alternately repeated at the target interval shown in Table 9, and The target total layer having a component concentration distribution structure in which the Ti content continuously changes from the highest Ti content point to the lowest Ti content point, from the lowest Ti content point to the highest Ti content point, and also shown in Table 9 The surface-coated cermet end mills (hereinafter referred to as the present invention-coated end mills) 1 to 8 as the present invention-coated cermet tools were produced by depositing a thick hard coating layer, respectively.
[0029]
For the purpose of comparison, the surface of the cermet substrate (end mill) C-1 to C-8 is ultrasonically cleaned in acetone and dried, and 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 (Al, Ti, B) ) End coat mills made of conventional surface-coated cermets (hereinafter referred to as conventional coated end mills) 1 to 8 as conventional coated cermet tools were produced by vapor-depositing a hard coating layer consisting of N layers.
[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 / SKD61 plate material,
Cutting speed: 200 m / min. ,
Groove depth (cut): 0.1 mm,
Table feed: 1000 mm / min,
With respect to the dry high-speed grooving test of the hardened 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 dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SCM435 plate material,
Cutting speed: 300 m / min. ,
Groove depth (cut): 1mm,
Table feed: 800mm / min,
For the dry high-speed grooving 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 / FC250 plate material,
Cutting speed: 250 m / min. ,
Groove depth (cut): 4.5 mm,
Table feed: 500 mm / min,
The cast iron was subjected to dry high-speed grooving test under the above conditions, and in each of the grooving tests, cutting until the flank wear width of the outer peripheral edge of the cutting edge reached 0.1 mm, which is a guide for the service life The groove length 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 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 condition as in Example 1 above, the lowest Ti content point and the highest Ti content point of the target composition shown in Table 11 along the layer thickness direction are alternately at the target interval shown in Table 11 It has a component concentration distribution structure that repeatedly exists and has a Ti content continuously changing from the highest Ti content point to the lowest Ti content point, and from the lowest Ti content point to the highest Ti content point, and also Table 11 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.
[0036]
In addition, for the purpose of comparison, the above cermet substrates (drills) D-1 to D-8 Cutting edge In addition, honing is performed, ultrasonic cleaning is performed in acetone, and in a dry state, a normal arc ion plating apparatus shown in FIG. 2 is also inserted. Under the same conditions as in Example 1, Table 12 shows Conventionally coated cermet tools by depositing a hard coating layer consisting of an (Al, Ti, B) N layer having the indicated target composition and target layer thickness and having substantially no composition change along the layer thickness direction Conventional surface-coated cermet drills (hereinafter referred to as conventional coated drills) 1 to 8 were manufactured.
[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, thickness: 50 mm JIS / SS400 plate material,
Cutting speed: 150 m / min. ,
Feed: 0.18mm / rev,
Hole depth: 8mm,
About the wet high-speed drilling test of structural 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 / S50C plate material,
Cutting speed: 120 m / min. ,
Feed: 0.23mm / rev,
Hole depth: 16mm,
For the wet high speed drilling test of carbon steel under the conditions of the present invention, 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 / SCM420 plate material,
Cutting speed: 70 m / min. ,
Feed: 0.23mm / rev,
Hole depth: 32mm,
Wet high-speed drilling test of alloy steel under the above conditions, each wet high-speed drilling cutting test (using water-soluble cutting oil) until the flank wear width of the cutting edge surface reaches 0.3mm The number of holes drilled was measured. The measurement results are shown in Tables 11 and 12, respectively.
[0038]
[Table 11]

[0039]
[Table 12]

[0040]
The highest Ti content point and the lowest Ti in the hard coating layer constituting the inventive coated chips 1-16, the present coated end mills 1-8, and the present coated drills 1-8 as the present coated cermet tool 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 Ti content point and the lowest Ti content point had the same composition and spacing as the target values, respectively. Ti component content is present alternately and from the highest Ti content point to the lowest Ti content point, from the lowest Ti content point to the highest Ti 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.
[0041]
【The invention's effect】
From the results shown in Tables 3 to 12, in the hard coating layer, the Ti lowest content point and the Ti highest content point are repeatedly present alternately at predetermined intervals in the layer thickness direction, and the Ti lowest content point is from the Ti highest content point. The coated cermet tool of the present invention having a component concentration distribution structure in which the Ti content continuously changes from the content point, the Ti minimum content point to the Ti maximum content point, all involve cutting of steel and cast iron with high heat generation. A conventional coated cermet comprising a (Al, Ti, B) N layer in which the hard coating layer has substantially no compositional change along the layer thickness direction while exhibiting excellent wear resistance even at high speeds. In high-speed cutting with high temperature, it is clear that the cutting edge wear progresses rapidly due to high-temperature hardness and insufficient heat resistance, and the service life is reached in a relatively short time.
As described above, the coated cermet tool of the present invention exhibits excellent wear resistance even in high-speed cutting such as various types of steel and cast iron, and exhibits excellent cutting performance over a long period of time. It can cope with high performance of processing equipment, labor saving and energy saving of cutting work, and further 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 the Ti-containing point forming Al- Using an arc ion plating apparatus in which a Ti—B alloy and an Al—Ti—B alloy for forming a minimum 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. while, by generating arc discharge between the cathode (evaporation source) and an anode electrode on both sides of the the surface of the substrate, Al and T 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 Ti content point and the lowest Ti content point are alternately present at predetermined intervals along the thickness direction, and the lowest Ti content point, the Ti content from the highest Ti content point, A component concentration distribution structure in which the Ti content continuously changes from the lowest content point to the Ti highest content point,
Furthermore, the Ti maximum content point, composition _{_{_{_{formula: [Al 1- (X + Y}}}} ) Ti X B Y] N ( provided that an atomic ratio, X is 0.35 to 0.55, Y is 0.01 0.10),
The Ti minimum content point, composition _{_{_{_{formula: [Al 1- (X + Y}}}} ) Ti X B Y] N ( provided that an atomic ratio, X is 0.05 to 0.25, Y is from 0.01 to 0. 10),
And the interval between the adjacent highest Ti content point and the lowest Ti content point is 0.01 to 0.1 μm,
A surface-coated cermet cutting tool that exhibits excellent wear resistance with a hard coating layer in high-speed cutting.