JP3978722B2

JP3978722B2 - Surface coated cemented carbide cutting tool with excellent wear resistance with hard coating layer in high speed cutting

Info

Publication number: JP3978722B2
Application number: JP2002241854A
Authority: JP
Inventors: 秀充高岡; 惠滋中村
Original assignee: Mitsubishi Materials Corp
Current assignee: Mitsubishi Materials Corp
Priority date: 2002-08-22
Filing date: 2002-08-22
Publication date: 2007-09-19
Anticipated expiration: 2022-08-22
Also published as: JP2004074378A

Description

【０００１】
【発明の属する技術分野】
この発明は、硬質被覆層が一段とすぐれた高温硬さおよび耐熱性を有し、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超硬合金製切削工具（以下、被覆超硬工具という）に関するものである。
【０００２】
【従来の技術】
一般に、被覆超硬工具には、各種の鋼や鋳鉄などの被削材の旋削加工や平削り加工にバイトの先端部に着脱自在に取り付けて用いられるスローアウエイチップ、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、被覆超硬工具として、炭化タングステン（以下、ＷＣで示す）基超硬合金または炭窒化チタン（以下、ＴｉＣＮで示す）基サーメットからなる基体（以下、これらを総称して超硬基体と云う）の表面に、組成式：［Ａｌ_1-( _Ｍ ₊ _Ｚ ₎Ｔｉ_ＭＲＮｂ_Ｚ］Ｎ（ただし、原子比で、Ｍは０．３５〜０．５５、Ｚは０．０１〜０．１５を示す）を満足するＡｌとＴｉとＮｂの複合窒化物［以下、（Ａｌ，Ｔｉ，Ｎｂ）Ｎで示す］層からなる硬質被覆層を１〜１５μｍの平均層厚で物理蒸着してなる被覆超硬工具が知られており、前記硬質被覆層はＡｌによる高温硬さと耐熱性、Ｔｉによる強度、さらにＮｂによる高温硬さを具備することから、これが各種の鋼や鋳鉄などの連続切削や断続切削加工に用いられることも良く知られるところである（例えば参考文献１参照）。
【０００４】
さらに、上記の被覆超硬工具が、例えば図２に概略説明図で示される物理蒸着装置の１種であるアークイオンプレーティング装置に上記の超硬基体を装入し、ヒーターで装置内を、例えば４５０℃の温度に加熱した状態で、アノード電極と所定組成を有するＡｌ−Ｔｉ−Ｎｂ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：９５Ａの条件でアーク放電を発生させ、同時に装置内に反応ガスとして窒素ガスを導入して、例えば２Ｐａの反応雰囲気とし、一方上記超硬基体には、例えば−１８０Ｖのバイアス電圧を印加した条件で、前記超硬基体の表面に、上記（Ａｌ，Ｔｉ，Ｎｂ）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（例えば参考文献２参照）。
【０００５】
【参考文献１】
特開平９−３２３２０４号公報
【参考文献２】
特開２０００−６１７０８号公報
【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にあるが、上記の従来被覆超硬工具においては、これを通常の切削加工条件で用いた場合には問題はないが、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を具備するものの、高温硬さおよび耐熱性を不十分であるため、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超硬工具を開発すべく、上記の従来被覆超硬工具を構成する硬質被覆層に着目し、研究を行った結果、
（ａ）上記の図２に示されるアークイオンプレーティング装置を用いて形成された従来被覆超硬工具を構成する（Ａｌ，Ｔｉ，Ｎｂ）Ｎ層は、層厚全体に亘って均質な高温硬さと耐熱性、強度、さらに高温強度を有するが、例えば図１（ａ）に概略平面図で、同（ｂ）に概略正面図で示される構造のアークイオンプレーティング装置、すなわち装置中央部に超硬基体装着用回転テーブルを設け、前記回転テーブルを挟んで、一方側に上記の従来（Ａｌ，Ｔｉ，Ｎｂ）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−Ｎｂ合金に相当する相対的にＴｉ含有量の高いＡｌ−Ｔｉ−Ｎｂ合金、他方側に相対的にＴｉ含有量の低いＡｌ−Ｔｉ−Ｎｂ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超硬基体をリング状に装着し、この状態で装置内雰囲気を窒素雰囲気として前記回転テーブルを回転させると共に、蒸着形成される硬質被覆層の層厚均一化を図る目的で超硬基体自体も自転させながら、前記の両側のカソード電極（蒸発源）とアノード電極との間にアーク放電を発生させて、前記超硬基体の表面に（Ａｌ，Ｔｉ，Ｎｂ）Ｎ層を形成すると、この結果の（Ａｌ，Ｔｉ，Ｎｂ）Ｎ層においては、回転テーブル上にリング状に配置された前記超硬基体が上記の一方側の相対的にＴｉ含有量の高いＡｌ−Ｔｉ−Ｎｂ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、また前記超硬基体が上記の他方側の相対的にＴｉ含有量の低いＡｌ−Ｔｉ−Ｎｂ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厚さ方向にそって前記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，Ｎｂ）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、超硬基体が装着されている回転テーブルの回転速度を制御して、
上記Ｔｉ最高含有点が、組成式：［Ａｌ_1-( _Ｍ ₊ _Ｚ ₎Ｔｉ_ＭＮｂ_Ｚ］Ｎ（ただし、原子比で、Ｍは０．４０〜０．５５、Ｚは０．０１〜０．１５を示す）、
上記Ｔｉ最低含有点が、組成式：［Ａｌ_1-( _Ｘ ₊ _Ｚ ₎Ｔｉ_ＸＮｂ_Ｚ］Ｎ（ただし、原子比で、Ｘは０．０５〜０．２５、Ｚは０．０１〜０．１５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，Ｎｂ）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最高含有点部分は、前記従来（Ａｌ，Ｔｉ，Ｎｂ）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、高い強度を保持し、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、かつＮｂによる高温強度も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、Ｎｂ）Ｎ層からなる被覆超硬工具は、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、装置中央部に超硬基体装着用回転テーブルを設け、前記回転テーブルを挟んで、一方側にＴｉ最高含有点形成用Ａｌ−Ｔｉ−Ｎｂ合金、他方側にＴｉ最低含有点形成用Ａｌ−Ｔｉ−Ｎｂ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外周部に沿って複数の超硬基体をリング状に装着し、この状態で装置内雰囲気を窒素雰囲気として前記回転テーブルを回転させると共に、前記超硬基体自体も自転させながら、前記の両側のカソード電極（蒸発源）とアノード電極との間にアーク放電を発生させて、前記超硬基体の表面に、（Ａｌ，Ｔｉ，Ｎｂ）Ｎ層からなる硬質被覆層を１〜１５μｍの全体平均層厚で蒸着してなる被覆超硬工具にして、
上記硬質被覆層が、厚さ方向にそって、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最高含有点が、組成式：［Ａｌ_1-( _Ｍ ₊ _Ｚ ₎Ｔｉ_ＭＮｂ_Ｚ］Ｎ（ただし、原子比で、Ｍは０．４０〜０．５５、Ｚは０．０１〜０．１５を示す）、
上記Ｔｉ最低含有点が、組成式：［Ａｌ_1-( _Ｘ ₊ _Ｚ ₎Ｔｉ_ＸＮｂ_Ｚ］Ｎ（ただし、原子比で、Ｘは０．０５〜０．２５、Ｚは０．０１〜０．１５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超硬工具に特徴を有するものである。
【００１０】
つぎに、この発明の被覆超硬工具において、これを構成する硬質被覆層の構成を上記の通りに限定した理由を説明する。
（ａ）Ｔｉ最低含有点の組成
Ｔｉ最低含有点の（Ａｌ，Ｔｉ，Ｎｂ）ＮにおけるＡｌ成分は高温硬さおよび耐熱性を向上させ、一方同Ｔｉ成分は強度を向上させ、さらに同Ｎｂ成分はＡｌとの共存において層の高温強度を一段と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するようにしたものであるが、Ｔｉの割合を示すＸ値がＡｌとＮｂ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Ｔｉ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および耐熱性を確保することができなくなるものであり、またＮｂ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強度向上効果が得られず、この結果チッピングが発生し易くなり、一方同Ｚ値が０．１５を超えても、所望の高温強度を確保することが困難になることから、Ｘ値を０．０５〜０．２５、Ｚ値を０．０１〜０．１５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および耐熱性のすぐれたものであるが、反面強度の劣るものであるため、このＴｉ最低含有点の強度不足を補う目的で、上記の従来（Ａｌ，Ｔｉ，Ｎｂ）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成分の割合を示すＭ値がＡｌおよびＮｂ成分との合量に占める割合（原子比）で０．４０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Ｍ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最高含有点に所望の高温硬さおよび耐熱性を具備せしめることができなくなることから、Ｔｉ最高含有点でのＴｉ成分の割合を示すＭ値を０．４０〜０．５５と定めた。
また、Ｔｉ最高含有点におけるＮｂ成分は、上記の通り高温強度を向上させ、もって耐チッピング性の向上に寄与する作用をもつものであり、したがってＺ値が０．０１未満では所望の高温強度向上効果が得られず、一方Ｚ値が０．１５を越えても、所望の高温強度を確保することが困難になることから、Ｚ値を０．０１〜０．１５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、この結果層に所望の高温特性と強度および靭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Ｔｉ最低含有点であれば強度および靭性不足、Ｔｉ最高含有点であれば高温硬さおよび耐熱性不足が層内に局部的に現れ、これが原因で切刃にチッピングが発生し易くなったり、摩耗進行が促進されるようになることから、その間隔を０．０１〜０．１μmと定めた。
【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、この発明の被覆超硬工具を実施例により具体的に説明する。
（実施例１）
原料粉末として、いずれも０．８〜３．２μｍ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：１４１０℃に１時間保持の条件で焼結し、焼結後、切刃部分にＲ：０．０３のホーニング加工を施してＩＳＯ規格・ＳＮＭＧ１２０４１２のチップ形状をもったＷＣ基超硬合金製のチップ超硬基体Ａ−１〜Ａ−４，Ａ−６，およびＡ−８〜Ａ−１０をそれぞれ形成した。
【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７２時間湿式混合し、乾燥した後、１００ＭＰａの圧力で圧粉体にプレス成形し、この圧粉体を２ｋＰａの窒素雰囲気中、温度：１５１０℃に１時間保持の条件で焼結し、焼結後、切刃部分にＲ：０．０３のホーニング加工を施してＩＳＯ規格・ＳＮＭＧ１２０４１２のチップ形状をもったＴｉＣＮ系サーメット製のチップ超硬基体Ｂ−２〜Ｂ−６をそれぞれ形成した。
【００１６】
ついで、上記のチップ超硬基体Ａ−１〜Ａ−４，Ａ−６，およびＡ−８〜Ａ−１０、並びにＢ−２〜Ｂ−６のそれぞれを、アセトン中で超音波洗浄し、乾燥した状態で、図１に示されるアークイオンプレーティング装置内の回転テーブル上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−Ｎｂ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−Ｎｂ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４７０℃に加熱した後、前記回転テーブル上で自転しながら回転するチップ超硬基体に−１０００Ｖの直流バイアス電圧を印加し、かつカソード電極の前記金属Ｔｉとアノード電極との間に１００Ａの電流を流してアーク放電を発生させ、もってチップ超硬基体表面をＴｉボンバート洗浄し、ついで装置内に反応ガスとして窒素ガスを導入して３Ｐａの反応雰囲気とすると共に、前記回転テーブル上で自転しながら回転するチップ超硬基体に−４０Ｖ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−Ｎｂ合金およびＴｉ最高含有点形成用Ａｌ−Ｔｉ−Ｎｂ合金）とアノード電極との間に１５０Ａの電流を流してアーク放電を発生させ、もって前記チップ超硬基体の表面に、層厚方向に沿って表３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に示される目標全体層厚の硬質被覆層を蒸着することにより、本発明被覆超硬工具としての本発明表面被覆超硬合金製スローアウエイチップ（以下、本発明被覆超硬チップと云う）１〜１３をそれぞれ製造した。
【００１７】
また、比較の目的で、これらチップ超硬基体Ａ−１〜Ａ−４，Ａ−６，およびＡ−８〜Ａ−１０、並びにＢ−２〜Ｂ−６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−Ｎｂ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５５０℃に加熱した後、前記チップ超硬基体に−１０００Ｖの直流バイアス電圧を印加し、かつカソード電極の前記金属Ｔｉとアノード電極との間に１００Ａの電流を流してアーク放電を発生させて、チップ超硬基体表面をＴｉボンバート洗浄し、ついで装置内に反応ガスとして窒素ガスを導入して２Ｐａの反応雰囲気とすると共に、チップ超硬基体に印加するバイアス電圧を−１８０Ｖ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、もって前記チップ超硬基体のそれぞれの表面に、表４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，Ｎｂ）Ｎ層からなる硬質被覆層を蒸着することにより、従来被覆超硬工具としての従来表面被覆超硬合金製スローアウエイチップ（以下、従来被覆超硬チップと云う）１〜１３をそれぞれ製造した。
【００１８】
つぎに、上記本発明被覆超硬チップ１〜１３および従来被覆超硬チップ１〜１３について、これを工具鋼製バイトの先端部に固定治具にてネジ止めした状態で、
被削材：ＪＩＳ・Ｓ１５Ｃの丸棒、
切削速度：３５０ｍ／ｍｉｎ．、
切り込み：１．２ｍｍ、
送り：０．２ｍｍ／ｒｅｖ．、
切削時間：５分、
の条件での炭素鋼の乾式高速連続旋削加工試験、
被削材：ＪＩＳ・ＳＳ４００の長さ方向等間隔４本縦溝入り丸棒、
切削速度：３５５ｍ／ｍｉｎ．、
切り込み：１．５ｍｍ、
送り：０．１８ｍｍ／ｒｅｖ．、
切削時間：５分、
の条件での軟鋼の乾式高速断続旋削加工試験、さらに、
被削材：ＪＩＳ・ＦＣ２５０の長さ方向等間隔４本縦溝入り丸棒、
切削速度：３６０ｍ／ｍｉｎ．、
切り込み：２ｍｍ、
送り：０．２ｍｍ／ｒｅｖ．、
切削時間：５分、
の条件での鋳鉄の乾式高速断続旋削加工試験を行い、いずれの旋削加工試験でも切刃の逃げ面摩耗幅を測定した。この測定結果を表５に示した。
【００１９】
【表１】

【００２０】
【表２】

【００２１】
【表３】

【００２２】
【表４】

【００２３】
【表５】

【００２４】
（実施例２）
原料粉末として、平均粒径：４．０μｍ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１．８μｍのＣｒ₃Ｃ₂粉末、同１．５μｍのＶＣ粉末、同１．０μｍの（Ｔｉ，Ｗ）Ｃ［質量比で、ＴｉＣ／ＷＣ＝５０／５０］粉末、および同１．８μｍのＣｏ粉末を用意し、これら原料粉末をそれぞれ表６に示される配合組成に配合し、さらにワックスを加えてアセトン中で７２時間ボールミル混合し、減圧乾燥した後、１００ＭＰａの圧力で所定形状の各種の圧粉体にプレス成形し、これらの圧粉体を、６Ｐａの真空雰囲気中、７℃／分の昇温速度で１３７０〜１４７０℃の範囲内の所定の温度に昇温し、この温度に１時間保持後、炉冷の条件で焼結して、直径が８ｍｍ、１３ｍｍ、および２６ｍｍの３種の超硬基体形成用丸棒焼結体Ｃ−１〜Ｃ−８を形成し、さらに前記の３種の丸棒焼結体のうちの丸棒焼結体Ｃ−１，Ｃ−２，およびＣ−４〜Ｃ−８から、研削加工にて、表６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の寸法を有し、かついずれもねじれ角：３０度の４枚刃スクエア形状をもったエンドミル超硬基体をそれぞれ製造した。
【００２５】
ついで、これらのエンドミル超硬基体を、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７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７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７に示される目標全体層厚の硬質被覆層を蒸着することにより、本発明被覆超硬工具としての本発明表面被覆超硬合金製エンドミル（以下、本発明被覆超硬エンドミルと云う）１〜７をそれぞれ製造した。
【００２６】
また、比較の目的で、上記のエンドミル超硬基体を、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８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，Ｎｂ）Ｎ層からなる硬質被覆層を蒸着することにより、従来被覆超硬工具としての従来表面被覆超硬合金製エンドミル（以下、従来被覆超硬エンドミルと云う）１〜７をそれぞれ製造した。
【００２７】
つぎに、上記本発明被覆超硬エンドミル１〜７および従来被覆超硬エンドミル１〜７のうち、本発明被覆超硬エンドミル１，２および従来被覆超硬エンドミル１，２については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＦＣ２００の板材、
切削速度：３５０ｍ／ｍｉｎ．、
軸方向切り込み：３．５ｍｍ、
径方向切り込み：０．６５ｍｍ、
テーブル送り：５８０ｍｍ／分、
の条件での鋳鉄の湿式高速側面切削加工試験、本発明被覆超硬エンドミル３〜５および従来被覆超硬エンドミル３〜５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：３６０ｍ／ｍｉｎ．、
軸方向切り込み：４．８ｍｍ、
径方向切り込み：０．９ｍｍ、
テーブル送り：５９０ｍｍ／分、
の条件での軟鋼の湿式高速側面切削加工試験、本発明被覆超硬エンドミル６，７および従来被覆超硬エンドミル６，７については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・Ｓ１５Ｃの板材、
切削速度：３５５ｍ／ｍｉｎ．、
軸方向切り込み：８．０ｍｍ、
径方向切り込み：１．３ｍｍ、
テーブル送り：３８０ｍｍ／分、
の条件での炭素鋼の湿式高速側面切削加工試験をそれぞれ行い、いずれの側面切削加工試験（いずれの試験も水溶性切削油使用）でも切刃部の外周刃の逃げ面摩耗幅が使用寿命の目安とされる０．１ｍｍに至るまでの切削長を測定した。この測定結果を表７、８にそれぞれ示した。
【００２８】
【表６】

【００２９】
【表７】

【００３０】
【表８】

【００３１】
（実施例３）
上記の実施例２で製造した直径が８ｍｍ、１３ｍｍ、および２６ｍｍの３種の丸棒焼結体のうちの丸棒焼結体Ｃ−２〜Ｃ−８を用い、この丸棒焼結体から、研削加工にて、表６に示される組合せで、溝形成部の直径×長さがそれぞれ４ｍｍ×１３ｍｍ、８ｍｍ×２２ｍｍ、および１６ｍｍ×４５ｍｍの寸法を有し、かついずれもねじれ角：３０度の２枚刃形状をもったドリル超硬基体をそれぞれ製造した。
【００３２】
ついで、これらのドリル超硬基体の切刃に、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、本発明被覆超硬工具としての本発明表面被覆超硬合金製ドリル（以下、本発明被覆超硬ドリルと云う）１〜７をそれぞれ製造した。
【００３３】
また、比較の目的で、上記のドリル超硬基体の切刃に、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，Ｎｂ）Ｎ層からなる硬質被覆層を蒸着することにより、従来被覆超硬工具としての従来表面被覆超硬合金製ドリル（以下、従来被覆超硬ドリルと云う）１〜７をそれぞれ製造した。
【００３４】
つぎに、上記本発明被覆超硬ドリル１〜７および従来被覆超硬ドリル１〜７のうち、本発明被覆超硬ドリル１，２および従来被覆超硬ドリル１，２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．、
送り：０．２１ｍｍ／ｒｅｖ、
穴深さ：１０ｍｍ
の条件での軟鋼の湿式高速穴あけ切削加工試験、本発明被覆超硬ドリル３〜５および従来被覆超硬ドリル３〜５については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・Ｓ１５Ｃの板材、
切削速度：２４０ｍ／ｍｉｎ．、
送り：０．２４ｍｍ／ｒｅｖ、
穴深さ：１５ｍｍ
の条件での炭素鋼の湿式高速穴あけ切削加工試験、本発明被覆超硬ドリル６，７および従来被覆超硬ドリル６，７については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＦＣ２００の板材、
切削速度：２８５ｍ／ｍｉｎ．、
送り：０．３ｍｍ／ｒｅｖ、
穴深さ：２５ｍｍ
の条件での鋳鉄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９，１０にそれぞれ示した。
【００３５】
【表９】

【００３６】
【表１０】

【００３７】
この結果得られた本発明被覆超硬工具としての本発明被覆超硬チップ１〜１３、本発明被覆超硬エンドミル１〜７、および本発明被覆超硬ドリル１〜７、並びに従来被覆超硬工具としての従来被覆超硬チップ１〜１３、従来被覆超硬エンドミル１〜７、および従来被覆超硬ドリル１〜７をそれぞれ構成する硬質被覆層について、層厚方向に沿ってＡｌおよびＴｉ成分の含有量、さらにＮｂ成分の含有量をオージェ分光分析装置を用いて測定し、この測定結果から各測定点におけるＡｌおよびＴｉ成分の含有量を検討したところ、本発明被覆超硬工具では、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、Ｔｉ最高含有点から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。
一方前記従来被覆超硬工具の硬質被覆層では、層厚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。
【００３８】
【発明の効果】
表３〜１０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超硬工具は、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、Ｎｂ成分による高温強度向上効果と相俟ってすぐれた耐摩耗性を発揮するのに対して、硬質被覆層が厚さ方向に沿って実質的に組成変化のない（Ａｌ，Ｔｉ，Ｎｂ）Ｎ層からなる従来被覆超硬工具においては、高温を伴う高速切削加工では前記層の高温硬さおよび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、この発明の被覆超硬工具は、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】この発明の被覆超硬工具を構成する硬質被覆層を形成するのに用いたアークイオンプレーティング装置を示し、（ａ）は概略平面図、（ｂ）は概略正面図である。
【図２】従来被覆超硬工具を構成する硬質被覆層を形成するのに用いた通常のアークイオンプレーティング装置の概略説明図である。[0001]
BACKGROUND OF THE INVENTION
This invention has a surface coating super-hard coating layer that has excellent high-temperature hardness and heat resistance, and therefore exhibits excellent wear resistance especially in high-speed cutting with high heat generation such as various steels and cast iron. The present invention relates to a hard alloy cutting tool (hereinafter referred to as a coated carbide tool).
[0002]
[Prior art]
Generally, for coated carbide tools, a throw-away tip that is attached to the tip of a cutting tool for turning or flattening of various steel and cast iron work materials, and drilling of the work material. There are drills and miniature drills used for processing, etc., and solid type end mills used for chamfering, grooving, shoulder processing, etc. of the work material. A slow-away end mill tool that performs cutting work in the same manner as a type end mill is known.
[0003]
Further, as a coated carbide tool, a substrate made of tungsten carbide (hereinafter referred to as WC) -based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) -based cermet (hereinafter collectively referred to as a cemented carbide substrate). on the surface of) the composition _{_{_{_{formula: [Al 1- (M + Z}}}} ) Ti M RNb Z] N ( provided that an atomic ratio, M is 0.35 to 0.55, Z is a 0.01 to 0.15 A hard coating layer composed of a composite nitride of Al, Ti, and Nb [hereinafter referred to as (Al, Ti, Nb) N] layer that satisfies the following conditions: physical vapor deposition with an average layer thickness of 1 to 15 μm Hard tools are known, and since the hard coating layer has high-temperature hardness and heat resistance by Al, strength by Ti, and high-temperature hardness by Nb, this is continuous cutting and intermittent cutting of various steels and cast irons. It is also well known that it is used for processing. (See, for example, Reference 1).
[0004]
Furthermore, the above-mentioned coated carbide tool is, for example, the above-mentioned carbide substrate is loaded into an arc ion plating apparatus which is one type of physical vapor deposition apparatus schematically shown in FIG. For example, an arc discharge is generated between the anode electrode and a cathode electrode (evaporation source) on which an Al—Ti—Nb alloy having a predetermined composition is set, for example, at a current of 95 A, while being heated to a temperature of 450 ° C. At the same time, nitrogen gas is introduced into the apparatus as a reaction gas to create a reaction atmosphere of, for example, 2 Pa. On the other hand, the carbide substrate is applied to the surface of the carbide substrate under a condition that a bias voltage of, for example, −180 V is applied. It is also known that it is produced by vapor-depositing a hard coating layer composed of the above (Al, Ti, Nb) N layer (see, for example, Reference 2).
[0005]
[Reference 1]
JP-A-9-323204 [Reference 2]
Japanese Patent Laid-Open No. 2000-61708 [0006]
[Problems to be solved by the invention]
In recent years, the performance of cutting machines has been remarkable. On the other hand, there is a strong demand for labor saving and energy saving and further cost reduction for cutting. With this trend, cutting tends to be faster. In a coated carbide 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. However, 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 developed a hard coating layer that constitutes the above-described conventional coated carbide tool in order to develop a coated carbide tool that exhibits excellent wear resistance particularly in high-speed cutting. As a result of conducting research with a focus on
(A) The (Al, Ti, Nb) N layer constituting the conventional coated carbide tool formed using the arc ion plating apparatus shown in FIG. 2 has a uniform high-temperature hardness over the entire layer thickness. It has heat resistance, strength, and high-temperature strength. For example, an arc ion plating apparatus having a structure shown in a schematic plan view in FIG. 1A and a schematic front view in FIG. An Al—Ti—Nb alloy used as a cathode electrode (evaporation source) for forming the conventional (Al, Ti, Nb) N layer on one side of the rotary table provided with a rotary table for mounting a hard substrate. An arc ion in which an Al—Ti—Nb alloy with a relatively high Ti content corresponding to the above and an Al—Ti—Nb alloy with a relatively low Ti content on the other side are arranged opposite to each other as a cathode electrode (evaporation source) Playe A plurality of cemented carbide substrates are attached 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 apparatus. While rotating the rotary table as an atmosphere and rotating the carbide substrate itself for the purpose of uniforming the thickness of the hard coating layer formed by vapor deposition, the cathode electrode (evaporation source) on both sides and the anode electrode are rotated. When an arc discharge is generated between them to form an (Al, Ti, Nb) N layer on the surface of the cemented carbide substrate, the resulting (Al, Ti, Nb) N layer has a ring shape on the rotary table. The highest Ti content point is formed in the layer when the cemented carbide substrate placed on the closest side to the cathode electrode (evaporation source) of the Al-Ti-Nb alloy having a relatively high Ti content on one side described above. And also said When the hard substrate is closest to the cathode electrode of the Al-Ti-Nb alloy having a relatively low Ti content on the other side, a Ti lowest content point is formed in the layer, and the rotation of the rotary table causes The Ti highest content point and the Ti lowest content point appear alternately with a predetermined interval along the thickness direction, the Ti highest content point to the Ti lowest content point, and the Ti lowest content point to the Ti highest content. To have a component concentration distribution structure in which the Ti content continuously changes.
[0008]
(B) In the (Al, Ti, Nb) 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 carbide substrate is By controlling the rotation speed of the mounted rotary table,
The Ti maximum content point, composition _{_{_{_{formula: [Al 1- (M + Z}}}} ) Ti M Nb Z] N ( provided that an atomic ratio, M is 0.40 to 0.55, Z is from 0.01 to 0. 15)
The Ti minimum content point, composition _{_{_{_{formula: [Al 1- (X + Z}}}} ) Ti X Nb Z] N ( provided that an atomic ratio, X is 0.05 to 0.25, Z is from 0.01 to 0. 15)
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, the Al content is relatively higher than the conventional (Al, Ti, Nb) N layer described above, and therefore, it exhibits even higher high temperature hardness and heat resistance, The highest Ti content point portion has the same composition as the conventional (Al, Ti, Nb) N layer, that is, a relatively low Al content and a high Ti content composition compared to the lowest Ti content point portion. Since it has high strength and the distance between the highest Ti content point and the lowest Ti content point is extremely small, it maintains high strength as a property of the entire layer and also maintains high temperature strength due to Nb. Coated carbide tools consisting of an (Al, Ti, Nb) N layer with a hard coating layer that has excellent high-temperature hardness and heat resistance, and high speed such as steel and cast iron with high heat generation Excellent machining It is like to exhibit wear resistance.
The research results shown in (a) and (b) above were obtained.
[0009]
The present invention has been made based on the above research results, and is provided with a carbide substrate mounting rotary table in the center of the apparatus, sandwiching the rotary table, and Ti-containing point forming Al- Using an arc ion plating apparatus in which a Ti—Nb alloy and an Al—Ti—Nb 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 this apparatus A plurality of cemented carbide substrates are mounted in a ring shape along the outer periphery at a position separated by a predetermined distance in the radial direction. In this state, the atmosphere inside the apparatus is changed to a nitrogen atmosphere and the rotary table is rotated. while rotating, by generating arc discharge between the cathode (evaporation source) and an anode electrode on both sides of the the surface of the carbide substrate, (Al, Ti, Nb) from the N layer That the hard layer in the overall average layer formed by vapor deposition in a thickness coated cemented carbide tools 1 to 15 m,
In the hard coating layer, the highest Ti content point and the lowest Ti content point are present alternately at predetermined intervals along the thickness direction, and from the highest Ti content point to the lowest Ti content point, the Ti 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- (M + Z}}}} ) Ti M Nb Z] N ( provided that an atomic ratio, M is 0.40 to 0.55, Z is 0.01 0.15),
The Ti minimum content point, composition _{_{_{_{formula: [Al 1- (X + Z}}}} ) Ti X Nb Z] N ( provided that an atomic ratio, X is 0.05 to 0.25, Z is from 0.01 to 0. 15)
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 carbide tool that exhibits excellent wear resistance with a hard coating layer in high-speed cutting.
[0010]
Next, in the coated carbide tool of the present invention, the reason why the structure of the hard coating layer constituting the tool is limited as described above will be described.
(A) Composition of the lowest Ti content point The Al component in (Al, Ti, Nb) N at the lowest Ti content point improves the high-temperature hardness and heat resistance, while the Ti component improves the strength and further the Nb component. Has the effect of further improving the high-temperature strength of the layer in the coexistence with Al. Therefore, the Ti content is relatively low at the Ti minimum content point, the Al content is increased, and high speed cutting with high heat generation is achieved. It has excellent high-temperature hardness and heat resistance to adapt, but when the X value indicating the ratio of Ti is less than 0.05 in the ratio (atomic ratio) to the total amount of Al and Nb, In particular, the ratio of Ti is excessively increased, and even if the highest Ti content point having high strength exists adjacently, a decrease in the strength of the layer itself is unavoidable, and as a result, chipping or the like is likely to occur. X value indicating the ratio of 0.2 If it exceeds 5, the proportion of Al becomes relatively small, and the high temperature hardness and heat resistance required for high-speed cutting cannot be secured, and the Z value indicating the proportion of Nb If the ratio (atomic ratio) in the total amount of Al and Ti is less than 0.01, the desired high-temperature strength improvement effect cannot be obtained, and as a result, chipping tends to occur, while the Z value exceeds 0.15. However, since it becomes difficult to ensure the desired high-temperature strength, the X value was set to 0.05 to 0.25, and the Z value was set to 0.01 to 0.15.
[0011]
(B) Composition of the highest Ti content point As described above, the lowest Ti content point is excellent in high-temperature hardness and heat resistance, but on the other hand, it is inferior in strength. For the purpose, the same composition as the above-mentioned conventional (Al, Ti, Nb) N layer, that is, the Ti highest content point where the Ti content is relatively high, while the Al content is low, thereby having high strength. Therefore, if the M value indicating the proportion of the Ti component is less than 0.40 in terms of the total amount of the Al and Nb components (atomic ratio), the desired excellent strength is obtained. On the other hand, if the M value exceeds 0.55, the ratio of Ti with respect to Al increases so that the highest Ti content point can have the desired high-temperature hardness and heat resistance. From disappearing, The M value indicating a ratio of Ti component in Ti up containing point was defined as 0.40 to 0.55.
In addition, the Nb component at the highest Ti content point has the effect of improving the high temperature strength as described above, thereby contributing to the improvement of chipping resistance. Therefore, if the Z value is less than 0.01, the desired high temperature strength is improved. No effect was obtained, and on the other hand, even if the Z value exceeded 0.15, it was difficult to ensure the desired high-temperature strength, so the Z value was determined to be 0.01 to 0.15.
[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. Strength and toughness cannot be ensured, and if the distance exceeds 0.1 μm, each point has a defect, that is, if Ti is the lowest content point, insufficient strength and toughness, and if Ti is the highest content point, high temperature hardness Insufficient heat resistance and locality appear locally in the layer, which makes it easier for chipping to occur on the cutting edge and promotes the progress of wear. It was determined.
[0013]
(D) Overall average layer thickness of hard coating layer If the layer thickness is less than 1 μm, the desired wear resistance cannot be ensured. On the other hand, if the average layer thickness exceeds 15 μm, chipping tends to occur. Therefore, the average layer thickness was determined to be 1 to 15 μm.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Next, the coated carbide tool of the present invention will be specifically described with reference to examples.
Example 1
As raw material powders, WC powder, TiC powder, VC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, and Co powder each having an average particle diameter of 0.8 to 3.2 μm are prepared. Were blended in the blending composition shown in Table 1, wet mixed for 72 hours with a ball mill, dried, and then pressed into a green compact at a pressure of 100 MPa. The green compact was heated in a vacuum of 6 Pa at a temperature of 1410. ℃ sintered under the conditions of 1 hour hold, after sintering, R the cutting edge portion: 0.03 WC-based cemented carbide made with a tip shape of ISO standard · SNMG120412 subjected to honing of the chip than Hard substrates A-1 to A-4, A-6, and A-8 to A-10 were formed, respectively.
[0015]
In addition, as raw material powders, all are TiCN (weight ratio, TiC / TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC having an average particle diameter of 0.5 to 2 μm. Prepare powder, Co powder, and Ni powder, blend these raw material powders into the composition shown in Table 2, wet mix for 72 hours with a ball mill, dry, and press-mold into green compact at 100 MPa pressure The green compact was sintered in a nitrogen atmosphere of 2 kPa at a temperature of 1510 ° C. for 1 hour. After sintering, the cutting edge portion was subjected to a honing process of R: 0.03 to meet ISO standards / Chip carbide substrates B-2 to B-6 made of TiCN cermet having a chip shape of SNMG120412 were formed.
[0016]
Next, each of the above-mentioned chip superhard substrates A-1 to A-4, A-6, and A-8 to A-10, and B-2 to B-6 was ultrasonically cleaned in acetone and dried. In this state, it is mounted along the outer periphery at a position that is a predetermined distance in the radial direction from the central axis on the rotary table in the arc ion plating apparatus shown in FIG. 1, and serves as a cathode electrode (evaporation source) on one side. Al-Ti-Nb alloy for forming Ti minimum content point having various component compositions, and Al-Ti-Nb for forming Ti maximum content point having various component compositions as a cathode electrode (evaporation source) on the other side The alloy is placed oppositely across the rotary table, and bombard cleaning metal Ti is also mounted. First, the inside of the apparatus is heated to 470 ° C. with a heater while evacuating the apparatus and maintaining a vacuum of 0.5 Pa or less. After the rotation table Making rotation on Le applying a DC bias voltage of -1000V the chip carbide substrate rotates while, and by flowing a 100A current between said metallic Ti and the anode electrode of the cathode electrode to generate arc discharge, it has been The surface of the chip carbide substrate is cleaned by Ti bombardment, nitrogen gas is introduced into the apparatus as a reaction gas to make a reaction atmosphere of 3 Pa, and the chip carbide substrate rotating while rotating on the rotary table has a voltage of -40V. A DC bias voltage was applied, and a current of 150 A was applied between each cathode electrode (the Al-Ti-Nb alloy for forming the lowest Ti content point and the Al-Ti-Nb alloy for forming the highest Ti content point) and the anode electrode. was arcing flowing on the surface of the chip carbide substrate have, Ti lowest target composition shown in Table 3 along the thickness direction Ti-containing organic points and Ti maximum content point and also are alternately repeatedly present in the target intervals indicated in Table 3, and the Ti lowest containing points from the Ti maximum content point, from the Ti lowest content point to the Ti maximum content point The surface coated carbide of the present invention as the coated carbide tool of the present invention has a component concentration distribution structure whose amount varies continuously and is vapor-deposited with a hard coating layer having a target total layer thickness also shown in Table 3. Alloy throwaway tips (hereinafter referred to as the present coated carbide tips) 1 to 13 were produced, respectively.
[0017]
For comparison purposes, these chip superhard substrates A-1 to A-4, A-6, A-8 to A-10, and B-2 to B-6 were ultrasonically cleaned in acetone. In the dry state, each was loaded into the ordinary arc ion plating apparatus shown in FIG. 2, and Al—Ti—Nb alloys having various component compositions were mounted as cathode electrodes (evaporation sources). The 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 550 ° C. with a heater, and then a −1000 V DC bias is applied to the chip carbide substrate. applying a voltage, and by flowing a 100A current to generate arc discharge between said metallic Ti and the anode electrode of the cathode electrode, the tip carbide substrate surface was washed Ti bombardment, then a reactive gas into the apparatus Nitrogen gas was introduced with a reactive atmosphere of 2 Pa, lowering the bias voltage applied to the chip carbide substrates -180 V, the cathode electrode and to generate arc discharge between the anode electrode, with it the tip than A hard coating comprising (Al, Ti, Nb) N layers having the target composition and the target layer thickness shown in Table 4 and substantially no composition change along the layer thickness direction on each surface of the hard substrate By depositing the layers, conventional surface-coated cemented carbide throwaway tips (hereinafter referred to as conventional coated carbide tips) 1 to 13 as conventional coated carbide tools were produced, respectively.
[0018]
Next, for the above-described coated carbide chips 1 to 13 and the conventional coated carbide chips 1 to 13 in the state where this is screwed to the tip of the tool steel tool with a fixing jig,
Work material: JIS / S15C round bar,
Cutting speed: 350 m / min. ,
Cutting depth: 1.2mm,
Feed: 0.2 mm / rev. ,
Cutting time: 5 minutes
Carbon steel dry high-speed continuous turning test,
Work material: JIS / SS400 lengthwise equidistant 4 round bars with flutes,
Cutting speed: 355 m / min. ,
Incision: 1.5mm,
Feed: 0.18 mm / rev. ,
Cutting time: 5 minutes
Dry high-speed intermittent turning test of mild steel under the conditions of
Work material: JIS · FC250 lengthwise equal length 4 round bar with round groove,
Cutting speed: 360 m / min. ,
Cutting depth: 2mm,
Feed: 0.2 mm / rev. ,
Cutting time: 5 minutes
A dry high-speed intermittent turning test of cast iron was performed under the conditions described above, and the flank wear width of the cutting edge was measured in any turning test. The measurement results are shown in Table 5 .
[0019]
[Table 1]

[0020]
[Table 2]

[0021]
[Table 3]

[0022]
[Table 4]

[0023]
[Table 5]

[0024]
(Example 2)
As raw material powder, medium coarse WC powder having an average particle size of 4.0 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, 1.8 μm Cr ₃ C ₂ powder, 1.5 μm VC powder, 1.0 μm (Ti, W) C [mass ratio, TiC / WC = 50/50] powder, and 1 Prepare 8 .mu.m Co powder, mix these raw material powders with the composition shown in Table 6, add wax, ball mill in acetone for 72 hours, dry under reduced pressure, and then press at a pressure of 100 MPa. The green compacts were press-molded, and these green compacts were heated to a predetermined temperature in the range of 1370 to 1470 ° C. at a rate of temperature increase of 7 ° C./min in a 6 Pa vacuum atmosphere. After holding at temperature for 1 hour, sintering under furnace cooling conditions Forming three types of cemented carbide substrate-forming round bar sintered bodies C-1 to C-8 having diameters of 8 mm, 13 mm, and 26 mm, and a round bar among the above three types of round bar sintered bodies From the sintered bodies C-1, C-2, and C-4 to C-8 , the diameter x length of the cutting edge portion is 6 mm × 13 mm, 10 mm ×, respectively, in the combinations shown in Table 6 by grinding. End mill cemented carbide substrates having dimensions of 22 mm and 20 mm × 45 mm and having a four-blade square shape with a twist angle of 30 degrees were manufactured.
[0025]
Next, these end mill carbide substrates were ultrasonically cleaned in acetone and dried, and then charged into the arc ion plating apparatus shown in FIG. The lowest Ti content point and the highest Ti content point of the target composition shown in Table 7 along the thickness direction are alternately repeated at the same target interval shown in Table 7 , and from the highest Ti content point to the lowest Ti content A hard coating layer having a component concentration distribution structure in which the Ti content continuously changes from the lowest Ti content point to the highest Ti content point, and having a target total layer thickness also shown in Table 7 Thus, end mills made of the surface coated cemented carbide of the present invention (hereinafter referred to as the present coated carbide end mills) 1 to 7 as the coated carbide tools of the present invention were produced.
[0026]
For comparison purposes, the above-mentioned end mill cemented carbide substrate was ultrasonically cleaned in acetone and dried, and charged into a normal arc ion plating apparatus shown in FIG. A hard coating layer composed of an (Al, Ti, Nb) N layer having the target composition and target layer thickness shown in Table 8 and substantially no composition change along the layer thickness direction. By vapor deposition, conventional surface-coated cemented carbide end mills (hereinafter referred to as conventional coated carbide end mills) 1 to 7 as conventional coated cemented carbide tools were produced, respectively.
[0027]
Next, of the present invention coated carbide end mills 1 to 7 and the conventional coated carbide end mills 1 to 7 , the present coated carbide end mills 1 and 2 and the conventional coated carbide end mills 1 and 2 ,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / FC200 plate material,
Cutting speed: 350 m / min. ,
Axial cut: 3.5mm,
Radial notch: 0.65mm,
Table feed: 580 mm / min,
About the wet high-speed side cutting test of cast iron under the conditions of the present invention, the coated carbide end mills 3-5 of the present invention and the conventional coated carbide end mills 3-5 ,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / SS400 plate material,
Cutting speed: 360 m / min. ,
Axial cut: 4.8mm,
Radial notch: 0.9mm,
Table feed: 590 mm / min,
For the wet high-speed side cutting test of mild steel under the conditions of the present invention, the coated carbide end mills 6 and 7 and the conventional coated carbide end mills 6 and 7
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / S15C plate,
Cutting speed: 355 m / min. ,
Axial cut: 8.0 mm,
Radial notch: 1.3mm,
Table feed: 380 mm / min,
The wet high-speed side cutting test of carbon steel under the above conditions is performed, and the flank wear width of the outer peripheral edge of the cutting edge is the service life of any side cutting test (both tests use water-soluble cutting oil). The cutting length up to 0.1 mm, which is a standard, was measured. The measurement results are shown in Tables 7 and 8 , respectively.
[0028]
[Table 6]

[0029]
[Table 7]

[0030]
[Table 8]

[0031]
(Example 3)
Using the round bar sintered bodies C-2 to C-8 among the three types of round bar sintered bodies having diameters of 8 mm, 13 mm, and 26 mm manufactured in Example 2 above, this round bar sintered body was used. In the grinding process, in the combinations shown in Table 6, the diameter x length of the groove forming part has dimensions of 4 mm x 13 mm, 8 mm x 22 mm, and 16 mm x 45 mm, respectively, and the twist angle is 30 degrees. Drilled carbide substrates each having a two-blade shape were manufactured.
[0032]
Next, honing is performed on the cutting blades of these drill carbide substrates , ultrasonic cleaning in acetone is performed, and the dried state is inserted into the arc ion plating apparatus shown in FIG. Under the same conditions, the lowest Ti content point and the highest Ti content point of the target composition shown in Table 9 along the layer thickness direction are alternately present at the same target interval shown in Table 9 , and the highest Ti content. the Ti lowest containing from point containing point, the Ti minimum Ti content from content point to the Ti maximum content point has a continuously changing component concentration distribution structure, and also of the entire target layer thickness shown in Table 9 By vapor-depositing the hard coating layer, drills made of the surface-coated cemented carbide of the present invention (hereinafter referred to as the present invention coated carbide drill) 1 to 7 as the coated carbide tool of the present invention were produced.
[0033]
Further, for the purpose of comparison, the cutting edge of the above-mentioned drill cemented carbide substrate is subjected to honing, ultrasonically cleaned in acetone, and dried, and then mounted on the ordinary arc ion plating apparatus shown in FIG. Then, under the same conditions as in Example 1, the target composition and the target layer thickness shown in Table 10 and (Al, Ti, Nb) N having substantially no composition change along the layer thickness direction are shown. By vapor-depositing a hard coating layer consisting of layers, conventional surface-coated cemented carbide drills (hereinafter referred to as conventional coated carbide drills) 1 to 7 as conventional coated carbide tools were produced, respectively.
[0034]
Next, of the present invention coated carbide drills 1 to 7 and the conventional coated carbide drills 1 to 7 , the present invention coated carbide drills 1 and 2 and the conventional coated carbide drills 1 and 2 ,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / SS400 plate material,
Cutting speed: 250 m / min. ,
Feed: 0.21mm / rev,
Hole depth: 10mm
For the wet high speed drilling test of mild steel under the above conditions, the present invention coated carbide drills 3-5 and the conventional coated carbide drills 3-5 ,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / S15C plate,
Cutting speed: 240 m / min. ,
Feed: 0.24mm / rev,
Hole depth: 15mm
For the wet high speed drilling test of carbon steel under the conditions of the present invention, the coated carbide drills 6 and 7 of the present invention and the conventional coated carbide drills 6 and 7 ,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / FC200 plate material,
Cutting speed: 285 m / min. ,
Feed: 0.3mm / rev,
Hole depth: 25mm
Wet cast high-speed drilling test of cast iron under the conditions of each, and any 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 drilling operations was measured. The measurement results are shown in Tables 9 and 10 , respectively.
[0035]
[Table 9]

[0036]
[Table 10]

[0037]
As a result, the present coated carbide tips 1 to 13 , the present coated carbide end mills 1 to 7 , the present coated carbide drills 1 to 7 , and the conventional coated carbide tools obtained as the present coated carbide tools. Conventionally coated carbide tips 1 to 13 , conventional coated carbide end mills 1 to 7 , and hard coated layers constituting conventional coated carbide drills 1 to 7 , containing Al and Ti components along the layer thickness direction The amount of Nb and the content of the Nb component were measured using an Auger spectroscopic analyzer, and the content of the Al and Ti components at each measurement point was examined from the measurement results. Points and Ti minimum content points alternately and repeatedly exist at substantially the same composition and interval as the target value, and from the highest Ti content point to the lowest Ti content point, the previous lowest Ti content point Ti Ti content to the highest content point is confirmed to have a continuously changing component concentration distribution structure, also showing the overall mean layer thickness even entire target layer thickness substantially identical values of a hard coating layer.
On the other hand, in the hard coating layer of the conventional coated carbide tool, no composition change is observed along the layer thickness direction, and the composition is substantially the same as the target composition and the overall average layer thickness is substantially the same as the target overall layer thickness. It was confirmed to show.
[0038]
【The invention's effect】
From the results shown in Tables 3 to 10 , in the hard coating layer, the Ti lowest content point and the Ti highest content point are alternately repeated at predetermined intervals in the layer thickness direction, and the Ti lowest content point is from the Ti highest content point. The coated carbide 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 of which are capable of generating high heat when cutting steel and cast iron. Even when performed at a high speed, the hard coating layer has substantially no composition change along the thickness direction while exhibiting excellent wear resistance in combination with the high temperature strength improvement effect by the Nb component ( In a conventional coated carbide tool composed of an Al, Ti, Nb) N layer, high-speed cutting with high temperature causes a rapid progress of wear of the cutting edge due to the high-temperature hardness and insufficient heat resistance of the layer, and a relatively short time. It is clear that it will reach the service life at
As described above, the coated carbide 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 is possible to satisfactorily cope with the high performance of the cutting device, the labor saving and energy saving of cutting, and the cost reduction.
[Brief description of the drawings]
FIG. 1 shows an arc ion plating apparatus used to form a hard coating layer constituting a coated carbide tool of the present invention, wherein (a) is a schematic plan view and (b) is a schematic front view.
FIG. 2 is a schematic explanatory view of a normal arc ion plating apparatus used to form a hard coating layer constituting a conventional coated carbide tool.

Claims

A rotating table for mounting either or both of a tungsten carbide base cemented carbide substrate and a titanium carbonitride-based cermet substrate is provided in the center of the apparatus, and the Ti-containing point forming Al- Using an arc ion plating apparatus in which a Ti—Nb alloy and an Al—Ti—Nb 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 this apparatus A plurality of the bases are mounted in a ring shape along the outer peripheral portion at a position separated by a predetermined distance in the radial direction, and in this state, the atmosphere inside the apparatus is set as a nitrogen atmosphere and the rotary table is rotated while the base body itself is rotated. , 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 Ti and N And a hard coating layer made of a composite nitride layer of the overall average layer surface-coated cemented carbide cutting tool comprising depositing a thickness of 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- (M + Z}}}} ) Ti M Nb Z] N ( provided that an atomic ratio, M is 0.40 to 0.55, Z is 0.01 0.15),
The Ti minimum content point, composition _{_{_{_{formula: [Al 1- (X + Z}}}} ) Ti X Nb Z] N ( provided that an atomic ratio, X is 0.05 to 0.25, Z is from 0.01 to 0. 15)
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 cemented carbide cutting tool that exhibits excellent wear resistance with a hard coating layer in high-speed cutting.