JP3928461B2

JP3928461B2 - Surface-coated cemented carbide cutting tool with excellent wear resistance under high-speed heavy cutting conditions.

Info

Publication number: JP3928461B2
Application number: JP2002104613A
Authority: JP
Inventors: 暁裕近藤; 和則佐藤; 裕介田中
Original assignee: Mitsubishi Materials Corp
Current assignee: Mitsubishi Materials Corp
Priority date: 2002-04-08
Filing date: 2002-04-08
Publication date: 2007-06-13
Anticipated expiration: 2022-04-08
Also published as: JP2003300103A

Description

【０００１】
【発明の属する技術分野】
この発明は、硬質被覆層がすぐれた高温硬さと耐熱性、さらに高強度と高靭性を有し、したがって各種の鋼や鋳鉄などの切削加工を、特に高熱発生を伴う高速で、かつ高い機械的衝撃を伴う高切り込みや高送りなどの重切削条件で行なった場合に、硬質被覆層がチッピング（微小欠け）などの発生なく、すぐれた耐摩耗性を発揮する表面被覆超硬合金製切削工具（以下、被覆超硬工具という）に関するものである。
【０００２】
【従来の技術】
一般に、被覆超硬工具には、各種の鋼や鋳鉄などの被削材の旋削加工や平削り加工にバイトの先端部に着脱自在に取り付けて用いられるスローアウエイチップ、穴あけ切削加工などに用いられるドリルやミニチュアドリル、さらに切刃が断続切削加工形態をとる面削加工や溝加工、肩加工などに用いられるソリッドタイプのエンドミルなどがあり、また前記スローアウエイチップを着脱自在に取り付けて前記ソリッドタイプのエンドミルと同様に切削加工を行うスローアウエイエンドミル工具などが知られている。
【０００３】
また、被覆超硬工具として、炭化タングステン（以下、ＷＣで示す）基超硬合金または炭窒化チタン（以下、ＴｉＣＮで示す）基サーメットからなる基体（以下、これらを総称して超硬基体と云う）の表面に、組成式：（Ｔｉ_1-XＡｌ_X）Ｎ（ただし、原子比で、Ｘは０．４０〜０．６５を示す）を満足するＴｉとＡｌの複合窒化物［以下、（Ｔｉ，Ａｌ）Ｎで示す］層からなる硬質被覆層を１〜１５μｍの平均層厚で物理蒸着してなる被覆超硬工具が提案され、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ている。
【０００４】
さらに、上記の被覆超硬工具が、例えば図２に概略説明図で示される物理蒸着装置の１種であるアークイオンプレーティング装置に上記の超硬基体を装入し、ヒータで装置内を、例えば５００℃の温度に加熱した状態で、アノード電極と所定組成を有するＴｉ−Ａｌ合金がセットされたカソード電極（蒸発源）との間に、例えば電流：９０Ａの条件でアーク放電を発生させ、同時に装置内に反応ガスとして窒素ガスを導入して、例えば２Ｐａの反応雰囲気とし、一方上記超硬基体には、例えば−１００Ｖのバイアス電圧を印加した条件で、前記超硬合金基体の表面に、上記（Ｔｉ，Ａｌ）Ｎ層からなる硬質被覆層を蒸着することにより製造されることも知られている。
【０００５】
【発明が解決しようとする課題】
近年の切削加工装置の高性能化はめざましく、一方で切削加工に対する省力化および省エネ化、さらに低コスト化の要求も強く、これに伴い、切削加工は高速で、かつ高切り込みや高送りなどの重切削条件で行なわれる傾向にあるが、上記の従来被覆超硬工具においては、これを通常の切削加工条件で用いた場合には問題はないが、切削加工を高熱発生および高い機械的衝撃を伴う高速重切削条件で行なった場合には、特に硬質被覆層の高温硬さおよび耐熱性が不足し、かつ強度および靭性も不十分であるために、硬質被覆層の摩耗進行が一段と促進し、かつチッピングも発生し易くなることから、比較的短時間で使用寿命に至るのが現状である。
【０００６】
【課題を解決するための手段】
そこで、本発明者等は、上述のような観点から、特に重切削加工条件で硬質被覆層がすぐれた耐チッピング性を発揮する被覆超硬工具を開発すべく、上記の従来被覆超硬工具を構成する硬質被覆層に着目し、研究を行った結果、
（ａ）上記の図２に示されるアークイオンプレーティング装置を用いて形成された従来被覆超硬工具を構成する（Ｔｉ，Ａｌ）Ｎ層は、層厚全体に亘って実質的に均一な組成を有し、したがって均質な高温硬さと耐熱性、さらに強度と靭性を有するが、例えば図１（ａ）に概略平面図で、同（ｂ）に概略正面図で示される構造のアークイオンプレーティング装置、すなわち装置中央部に超硬基体装着用回転テーブルを設け、前記回転テーブルを挟んで、一方側に相対的にＡｌ含有量の高い（Ｔｉ含有量の低い）Ａｌ−Ｔｉ合金、他方側に相対的にＴｉ含有量の高い（Ａｌ含有量の低い）Ｔｉ−Ａｌ合金をカソード電極（蒸発源）として対向配置したアークイオンプレーティング装置を用い、この装置の前記回転テーブルの外周部に沿って複数の超硬基体をリング状に装着し、この状態で装置内雰囲気を窒素雰囲気として前記回転テーブルを回転させると共に、蒸着形成される硬質被覆層の層厚均一化を図る目的で超硬基体自体も自転させながら、前記の両側のカソード電極（蒸発源）とアノード電極との間にアーク放電を発生させて、前記超硬基体の表面に（Ｔｉ，Ａｌ）Ｎ層を形成すると、この結果の（Ｔｉ，Ａｌ）Ｎ層においては、回転テーブル上にリング状に配置された前記超硬基体が上記の一方側の相対的にＡｌ含有量の高い（Ｔｉ含有量の低い）Ａｌ−Ｔｉ合金のカソード電極（蒸発源）に最も接近した時点で層中にＡｌ最高含有点が形成され、また前記超硬基体が上記の他方側の相対的にＴｉ含有量の高い（Ａｌ含有量の低い）Ｔｉ−Ａｌ合金のカソード電極に最も接近した時点で層中にＴｉ最高含有点が形成され、上記回転テーブルの回転によって層中には層厚方向にそって前記Ａｌ最高含有点とＴｉ最高含有点が所定間隔をもって交互に繰り返し現れると共に、前記Ａｌ最高含有点から前記Ｔｉ最高含有点、前記Ｔｉ最高含有点から前記Ａｌ最高含有点へＡｌおよびＴｉ含有量がそれぞれ連続的に変化する成分濃度分布構造をもつようになること。
【０００７】
（ｂ）上記（ａ）の繰り返し連続変化成分濃度分布構造の（Ｔｉ，Ａｌ）Ｎ層の形成において、対向配置の一方側のカソード電極（蒸発源）であるＡｌ−Ｔｉ合金におけるＡｌ含有量を上記の従来Ｔｉ−Ａｌ合金のＡｌ含有量に比して相対的に高いものとし、かつ同他方側のカソード電極（蒸発源）であるＴｉ−Ａｌ合金におけるＡｌ含有量を上記の従来Ｔｉ−Ａｌ合金のＡｌ含有量に比して相対的に低いものとする共に、超硬基体が装着されている回転テーブルの回転速度を制御して、
上記Ａｌ最高含有点が、組成式：（Ａｌ_1-XＴｉ_X）Ｎ（ただし、原子比で、Ｘは０．０５〜０．３０を示す）、
上記Ｔｉ最高含有点が、組成式：（Ｔｉ_1-YＡｌ_Y）Ｎ（ただし、原子比で、Ｙは０．０５〜０．３５を示す）、
をそれぞれ満足し、かつ隣り合う上記Ａｌ最高含有点とＴｉ最高含有点の厚さ方向の間隔を０．０１〜０．１μmとすると、
上記Ａｌ最高含有点部分では、上記の従来（Ｔｉ，Ａｌ）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（高温特性）を示し、一方上記Ｔｉ最高含有点部分では、前記従来（Ｔｉ，Ａｌ）Ｎ層に比してＴｉ含有量が相対的に高くなることから、一段と高い強度と靭性を具備し、かつこれらＡｌ最高含有点とＴｉ最高含有点の間隔をきわめて小さくしたことから、層全体の特性として高強度と高靭性を保持した状態ですぐれた高温特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（Ｔｉ，Ａｌ）Ｎ層からなる被覆超硬工具は、各種の鋼や鋳鉄などの切削加工を、特に高熱発生および高い機械的衝撃を伴う、高速重切削条件で行なった場合にも、硬質被覆層にチッピングの発生なく、すぐれた耐摩耗性を発揮するようになること。
以上（ａ）および（ｂ）に示される研究結果を得たのである。
【０００８】
この発明は、上記の研究結果に基づいてなされたものであって、装置中央部に超硬基体装着用回転テーブルを設け、前記回転テーブルを挟んで、一方側にＡｌ最高含有点形成用Ａｌ−Ｔｉ合金、他方側にＴｉ最高含有点形成用Ｔｉ−Ａｌ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、前記回転テーブルの外周部に沿って複数の超硬基体をリング状に装着し、この状態で装置内雰囲気を窒素雰囲気として前記回転テーブルを回転させると共に、超硬基体自体も自転させながら、前記の両側のカソード電極（蒸発源）とアノード電極との間にアーク放電を発生させて、超硬基体の表面に、（Ｔｉ，Ａｌ）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おいて、
上記硬質被覆層が、層厚方向にそって、Ａｌ最高含有点（Ｔｉ最低含有点）とＴｉ最高含有点（Ａｌ最低含有点）とが所定間隔をおいて交互に繰り返し存在し、かつ前記Ａｌ最高含有点から前記Ｔｉ最高含有点、前記Ｔｉ最高含有点から前記Ａｌ最高含有点へＡｌおよびＴｉ含有量がそれぞれ連続的に変化する成分濃度分布構造を有し、
さらに、上記Ａｌ最高含有点が、組成式：（Ａｌ_1-XＴｉ_X）Ｎ（ただし、原子比で、Ｘは０．０５〜０．３０を示す）、
上記Ｔｉ最高含有点が、組成式：（Ｔｉ_1-YＡｌ_Y）Ｎ（ただし、原子比で、Ｙは０．０５〜０．３５を示す）、
を満足し、かつ隣り合う上記Ａｌ最高含有点とＴｉ最高含有点の間隔が、０．０１〜０．１μmである、
高速重切削条件で硬質被覆層がすぐれた耐摩耗性を発揮する被覆超硬工具に特徴を有するものである。
【０００９】
つぎに、この発明の被覆超硬工具において、これを構成する硬質被覆層の構成を上記の通りに限定した理由を説明する。
（ａ）Ａｌ最高含有点の組成
Ａｌ最高含有点の（Ｔｉ，Ａｌ）ＮにおけるＡｌ成分は、高強度および高靭性を有するＴｉＮの高温硬さおよび耐熱性（高温特性）を向上させる目的で含有するものであり、したがってＡｌ成分の含有割合が高くなればなるほど高温特性は向上したものになるが、Ｔｉの割合を示すＸ値がＡｌとの合量に占める割合（原子比）で０．０５未満になると、相対的にＡｌの割合が多くなり過ぎて、高強度および高靭性を有するＴｉ最高含有点が隣接して存在しても層自体の強度および靭性の低下は避けられず、この結果チッピングなどが発生し易くなり、一方Ｔｉの割合を示すＸ値が同０．３０を越えると、相対的にＡｌの割合が少なくなり過ぎて、所望のすぐれた高温特性を確保することができなくなることから、Ｘ値を０．０５〜０．３０と定めた。
【００１０】
（ｂ）Ｔｉ最高含有点の組成
上記の通りＡｌ最高含有点は高温特性のすぐれたものであるが、反面強度および靭性の劣るものであるため、このＡｌ最高含有点の強度および靭性不足を補う目的で、Ｔｉ含有割合が高く、これによって高強度および高靭性を有するようになるＴｉ最高含有点を厚さ方向に交互に介在させるものであり、したがってＡｌの割合を示すＹ値がＴｉとの合量に占める割合（原子比）で０．３５を越えると、相対的にＡｌの割合が多くなり過ぎて、所望のすぐれた強度および靭性を確保することができず、一方Ａｌの割合を示すＹ値が同じく０．０５未満になると、相対的にＴｉの割合が多くなり過ぎて、Ｔｉ最高含有点に所望の高温特性を具備せしめることができなくなることから、Ｙ値を０．０５〜０．３５と定めた。
【００１１】
（ｃ）Ａｌ最高含有点とＴｉ最高含有点間の間隔
その間隔が０．０１μm未満ではそれぞれの点を上記の組成で明確に形成することが困難であり、この結果層に所望の高強度および高靭性、さらに高温特性を確保することができなくなり、またその間隔が０．１μmを越えるとそれぞれの点がもつ欠点、すなわちＡｌ最高含有点であれば強度および靭性不足、Ｔｉ最高含有点であれば高温特性不足が層内に局部的に現れ、これが原因で切刃にチッピングが発生し易くなったり、摩耗進行が促進されるようになることから、その間隔を０．０１〜０．１μmと定めた。
【００１２】
（ｄ）硬質被覆層の全体平均層厚
その層厚が１μｍ未満では、所望の耐摩耗性を確保することができず、一方その平均層厚が１５μｍを越えると、チッピングが発生し易くなることから、その平均層厚を１〜１５μｍと定めた。
【００１３】
【発明の実施の形態】
つぎに、この発明の被覆超硬工具を実施例により具体的に説明する。
（実施例１）
原料粉末として、いずれも１〜３μｍの平均粒径を有するＷＣ粉末、ＴｉＣ粉末、ＶＣ粉末、ＴａＣ粉末、ＮｂＣ粉末、Ｃｒ₃Ｃ₂粉末、およびＣｏ粉末を用意し、これら原料粉末を、表１に示される配合組成に配合し、ボールミルで７２時間湿式混合し、乾燥した後、１００ＭＰａの圧力で圧粉体にプレス成形し、この圧粉体を６Ｐａの真空中、温度：１４００℃に１時間保持の条件で焼結し、焼結後、切刃部分にＲ：０．０３のホーニング加工を施してＩＳＯ規格・ＣＮＭＧ１２０４０８のチップ形状をもったＷＣ基超硬合金製の超硬基体Ａ１〜Ａ１０を形成した。
【００１４】
また、原料粉末として、いずれも０．５〜２μｍの平均粒径を有するＴｉＣＮ（重量比でＴｉＣ／ＴｉＮ＝５０／５０）粉末、Ｍｏ₂Ｃ粉末、ＺｒＣ粉末、ＮｂＣ粉末、ＴａＣ粉末、ＷＣ粉末、Ｃｏ粉末、およびＮｉ粉末を用意し、これら原料粉末を、表２に示される配合組成に配合し、ボールミルで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系サーメット製の超硬基体Ｂ１〜Ｂ６を形成した。
【００１５】
ついで、上記の超硬基体Ａ１〜Ａ１０およびＢ１〜Ｂ６のそれぞれを、アセトン中で超音波洗浄し、乾燥した状態で、図１に示されるアークイオンプレーティング装置内の回転テーブル上に外周部にそって装着し、一方側のカソード電極（蒸発源）として、種々の成分組成をもったＴｉ最高含有点形成用Ｔｉ−Ａｌ合金、他方側のカソード電極（蒸発源）として、種々の成分組成をもったＡｌ最高含有点形成用Ａｌ−Ｔｉ合金を前記回転テーブルを挟んで対向配置し、またボンバート洗浄用金属Ｔｉも装着し、まず、装置内を排気して０．５Ｐａ以下の真空に保持しながら、ヒーターで装置内を５００℃に加熱した後、前記回転テーブル上で自転しながら回転する超硬基体に−１０００Ｖの直流バイアス電圧を印加し、カソード電極の前記金属Ｔｉとアノード電極との間に１００Ａの電流を流してアーク放電を発生させ、もって超硬基体表面をＴｉボンバート洗浄し、ついで装置内に反応ガスとして窒素ガスを導入して２Ｐａの反応雰囲気とすると共に、前記回転テーブル上で自転しながら回転する超硬基体に−１００Ｖの直流バイアス電圧を印加し、それぞれのカソード電極(前記Ｔｉ最高含有点形成用Ｔｉ−Ａｌ合金およびＡｌ最高含有点形成用Ａｌ−Ｔｉ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、もって前記超硬基体の表面に、層厚方向に沿って表３，４に示される目標組成のＡｌ最高含有点とＴｉ最高含有点とが交互に同じく表３，４に示される目標間隔で繰り返し存在し、かつ前記Ａｌ最高含有点から前記Ｔｉ最高含有点、前記Ｔｉ最高含有点から前記Ａｌ最高含有点へＡｌおよびＴｉ含有量がそれぞれ連続的に変化する成分濃度分布構造を有し、かつ同じく表３，４に示される目標全体層厚の硬質被覆層を蒸着することにより、図３（ａ）に概略斜視図で、同（ｂ）に概略縦断面図で示される形状を有する本発明被覆超硬工具としての本発明表面被覆超硬合金製スローアウエイチップ（以下、本発明被覆超硬チップと云う）１〜１６をそれぞれ製造した。
【００１６】
また、比較の目的で、これら超硬基体Ａ１〜Ａ１０およびＢ１〜Ｂ６を、アセトン中で超音波洗浄し、乾燥した状態で、それぞれ図２に示される通常のアークイオンプレーティング装置に装入し、カソード電極（蒸発源）として種々の成分組成をもったＴｉ−Ａｌ合金を装着し、さらにボンバート洗浄用金属Ｔｉも装着し、まず、装置内を排気して０．５Ｐａ以下の真空に保持しながら、ヒーターで装置内を５００℃に加熱した後、前記超硬基体に−１０００Ｖの直流バイアス電圧を印加し、カソード電極の前記金属Ｔｉとアノード電極との間に１００Ａの電流を流してアーク放電を発生させ、もって超硬基体表面をＴｉボンバート洗浄し、ついで装置内に反応ガスとして窒素ガスを導入して２Ｐａの反応雰囲気とすると共に、超硬基体に−１００Ｖの直流バイアス電圧を印加し、前記カソード電極のＴｉ−Ａｌ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、もって前記超硬基体Ａ１〜Ａ１０およびＢ１〜Ｂ６のそれぞれの表面に、表５，６に示される目標組成および目標層厚を有し、かつ層厚方向に沿って実質的に組成変化のない（Ｔｉ，Ａｌ）Ｎ層からなる硬質被覆層を蒸着することにより、同じく図３に示される形状の従来被覆超硬工具としての従来表面被覆超硬合金製スローアウエイチップ（以下、従来被覆超硬チップと云う）１〜１６をそれぞれ製造した。
【００１７】
つぎに、上記本発明被覆超硬チップ１〜１６および従来被覆超硬チップ１〜１６について、これを工具鋼製バイトの先端部に固定治具にてネジ止めした状態で、
被削材：ＪＩＳ・ＳＣＭ４４０の丸棒、
切削速度：３００ｍ／ｍｉｎ．、
切り込み：４ｍｍ、
送り：０．１５ｍｍ／ｒｅｖ．、
切削時間：８分、
の条件での合金鋼の乾式連続高速高切り込み切削加工試験、
被削材：ＪＩＳ・Ｓ４５Ｃの長さ方向等間隔４本縦溝入り丸棒、
切削速度：２５０ｍ／ｍｉｎ．、
切り込み：１．５ｍｍ、
送り：０．６ｍｍ／ｒｅｖ．、
切削時間：８分、
の条件での炭素鋼の乾式断続高速高送り切削加工試験、さらに、
被削材：ＪＩＳ・ＦＣ３００の丸棒、
切削速度：４００ｍ／ｍｉｎ．、
切り込み：４ｍｍ、
送り：０．２５ｍｍ／ｒｅｖ．、
切削時間：８分、
の条件での鋳鉄の乾式連続高速高切り込み切削加工試験を行い、いずれの切削加工試験でも切刃の逃げ面摩耗幅を測定した。この測定結果を表３〜６に示した。
【００１８】
【表１】

【００１９】
【表２】

【００２０】
【表３】

【００２１】
【表４】

【００２２】
【表５】

【００２３】
【表６】

【００２４】
（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７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種の超硬基体形成用丸棒焼結体を形成し、さらに前記の３種の丸棒焼結体から、研削加工にて、表７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の寸法をもった超硬基体（エンドミル）Ｃ−１〜Ｃ−８をそれぞれ製造した。
【００２５】
ついで、これらの超硬基体（エンドミル）Ｃ−１〜Ｃ−８を、アセトン中で超音波洗浄し、乾燥した状態で、同じく図１に示されるアークイオンプレーティング装置に装入し、上記実施例１と同一の条件で、層厚方向に沿って表８に示される目標組成のＡｌ最高含有点とＴｉ最高含有点とが交互に同じく表８に示される目標間隔で繰り返し存在し、かつ前記Ａｌ最高含有点から前記Ｔｉ最高含有点、前記Ｔｉ最高含有点から前記Ａｌ最高含有点へＡｌおよびＴｉ含有量がそれぞれ連続的に変化する成分濃度分布構造を有し、かつ同じく表８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、図４（ａ）に概略正面図で、同（ｂ）に切刃部の概略横断面図で示される形状を有する本発明被覆超硬工具としての本発明表面被覆超硬合金製エンドミル（以下、本発明被覆超硬エンドミルと云う）１〜８をそれぞれ製造した。
【００２６】
また、比較の目的で、上記の超硬基体（エンドミル）Ｃ−１〜Ｃ−８を、アセトン中で超音波洗浄し、乾燥した状態で、同じく図２に示される通常のアークイオンプレーティング装置に装入し、上記実施例１と同一の条件で、表９に示される目標組成および目標層厚を有し、かつ層厚方向に沿って実質的に組成変化のない（Ｔｉ，Ａｌ）Ｎ層からなる硬質被覆層を蒸着することにより、従来被覆超硬工具としての従来表面被覆超硬合金製エンドミル（以下、従来被覆超硬エンドミルと云う）１〜８をそれぞれ製造した。
【００２７】
つぎに、上記本発明被覆超硬エンドミル１〜８および従来被覆超硬エンドミル１〜８のうち、本発明被覆超硬エンドミル１〜３および従来被覆超硬エンドミル１〜３については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＳＫＤ１１の板材、
切削速度：１５０ｍ／ｍｉｎ．、
溝深さ（切り込み）：１．５ｍｍ、
テーブル送り：１５００ｍｍ／分、
の条件での工具鋼の乾式高速高送り溝切削加工試験、本発明被覆超硬エンドミル４〜６および従来被覆超硬エンドミル４〜６については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＳＵＳ３０４の板材、
切削速度：１２０ｍ／ｍｉｎ．、
溝深さ（切り込み）：７ｍｍ、
テーブル送り：６００ｍｍ／分、
の条件でのステンレス鋼の乾式高速高切り込み溝切削加工試験、本発明被覆超硬エンドミル７，８および従来被覆超硬エンドミル７，８については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＳＮＣＭ４３９の板材、
切削速度：２５０ｍ／ｍｉｎ．、
溝深さ（切り込み）：６ｍｍ、
テーブル送り：１０００ｍｍ／分、
の条件での合金鋼の乾式高速高送り溝切削加工試験をそれぞれ行い、いずれの溝切削加工試験でも切刃部の外周刃の逃げ面摩耗幅が使用寿命の目安とされる０．１ｍｍに至るまでの切削溝長を測定した。この測定結果を表８、９にそれぞれ示した。
【００２８】
【表７】

【００２９】
【表８】

【００３０】
【表９】

【００３１】
（実施例３）
上記の実施例２で製造した直径が８ｍｍ（超硬基体Ｃ−１〜Ｃ−３形成用）、１３ｍｍ（超硬基体Ｃ−４〜Ｃ−６形成用）、および２６ｍｍ（超硬基体Ｃ−７、Ｃ−８形成用）の３種の丸棒焼結体を用い、この３種の丸棒焼結体から、研削加工にて、溝形成部の直径×長さがそれぞれ４ｍｍ×１３ｍｍ（超硬基体Ｄ−１〜Ｄ−３）、８ｍｍ×２２ｍｍ（超硬基体Ｄ−４〜Ｄ−６）、および１６ｍｍ×４５ｍｍ（超硬基体Ｄ−７、Ｄ−８）の寸法をもった超硬基体（ドリル）Ｄ−１〜Ｄ−８をそれぞれ製造した。
【００３２】
ついで、これらの超硬基体（ドリル）Ｄ−１〜Ｄ−８の切刃に、ホーニングを施し、アセトン中で超音波洗浄し、乾燥した状態で、同じく図１に示されるアークイオンプレーティング装置に装入し、上記実施例１と同一の条件で、層厚方向に沿って表１０に示される目標組成のＡｌ最高含有点とＴｉ最高含有点とが交互に同じく表１０に示される目標間隔で繰り返し存在し、かつ前記Ａｌ最高含有点から前記Ｔｉ最高含有点、前記Ｔｉ最高含有点から前記Ａｌ最高含有点へＡｌおよびＴｉ含有量がそれぞれ連続的に変化する成分濃度分布構造を有し、かつ同じく表１０に示される目標全体層厚の硬質被覆層を蒸着することにより、図５（ａ）に概略正面図で、同（ｂ）に溝形成部の概略横断面図で示される形状を有する本発明被覆超硬工具としての本発明表面被覆超硬合金製ドリル（以下、本発明被覆超硬ドリルと云う）１〜８をそれぞれ製造した。
【００３３】
また、比較の目的で、上記の超硬基体（ドリル）Ｄ−１〜Ｄ−８の切刃に、ホーニングを施し、アセトン中で超音波洗浄し、乾燥した状態で、同じく図２に示される通常のアークイオンプレーティング装置に装入し、上記実施例１と同一の条件で、表１１に示される目標組成および目標層厚を有し、かつ層厚方向に沿って実質的に組成変化のない（Ｔｉ，Ａｌ）Ｎ層からなる硬質被覆層を蒸着することにより、従来被覆超硬工具としての従来表面被覆超硬合金製ドリル（以下、従来被覆超硬ドリルと云う）１〜８をそれぞれ製造した。
【００３４】
つぎに、上記本発明被覆超硬ドリル１〜８および従来被覆超硬ドリル１〜８のうち、本発明被覆超硬ドリル１〜３および従来被覆超硬ドリル１〜３については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＳＫＤ６１の板材、
切削速度：１２０ｍ／ｍｉｎ．、
送り：０．２ｍｍ／ｒｅｖ、
穴深さ：８ｍｍ
の条件での工具鋼の湿式高速高送り穴あけ切削加工試験、本発明被覆超硬ドリル４〜６および従来被覆超硬ドリル４〜６については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＦＣＤ４００の板材、
切削速度：２５０ｍ／ｍｉｎ．、
送り：０．３ｍｍ／ｒｅｖ、
穴深さ：１６ｍｍ
の条件でのダクタイル鋳鉄の湿式高速高送り穴あけ切削加工試験、本発明被覆超硬ドリル７，８および従来被覆超硬ドリル７，８については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＦＣ３００の板材、
切削速度：２００ｍ／ｍｉｎ．、
送り：０．４ｍｍ／ｒｅｖ、
穴深さ：３２ｍｍ
の条件での鋳鉄の湿式高速高送り穴あけ切削加工試験、をそれぞれ行い、いずれの湿式穴あけ切削加工試験（水溶性切削油使用）でも先端切刃面の逃げ面摩耗幅が０．３ｍｍに至るまでの穴あけ加工数を測定した。この測定結果を表１０、１１にそれぞれ示した。
【００３５】
【表１０】

【００３６】
【表１１】

【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１〜１６、本発明被覆超硬エンドミル１〜８、および本発明被覆超硬ドリル１〜８を構成する硬質被覆層におけるＡｌ最高含有点とＴｉ最高含有点の組成、並びに従来被覆超硬工具としての従来被覆超硬チップ１〜１６、従来被覆超硬エンドミル１〜８、および従来被覆超硬ドリル１〜８の硬質被覆層の組成をオージェ分光分析装置を用いて測定したところ、それぞれ目標組成と実質的に同じ組成を示した。
また、これらの本発明被覆超硬工具の硬質被覆層におけるＡｌ最高含有点とＴｉ最高含有点間の間隔、およびこれの全体層厚、並びに従来被覆超硬工具の硬質被覆層の厚さを、走査型電子顕微鏡を用いて断面測定したところ、いずれも目標値と実質的に同じ値を示した。
【００３８】
【発明の効果】
表３〜１１に示される結果から、硬質被覆層が層厚方向に、すぐれた高温硬さと耐熱性を有するＡｌ最高含有点と、高強度と高靭性を有するＴｉ最高含有点とが交互に所定間隔をおいて繰り返し存在し、かつ前記Ａｌ最高含有点から前記Ｔｉ最高含有点、前記Ｔｉ最高含有点から前記Ａｌ最高含有点へＡｌおよびＴｉ含有量がそれぞれ連続的に変化する成分濃度分布構造を有する本発明被覆超硬工具は、いずれも各種の鋼や鋳鉄などの切削加工を、高温発生を伴う高速条件で、かつ高い機械的衝撃を伴う高切り込みや高送りなどの重切削条件で行なった場合にも、硬質被覆層にチッピングの発生なく、すぐれた耐摩耗性を発揮するのに対して、硬質被覆層が層厚方向に沿って実質的に組成変化のない（Ｔｉ，Ａｌ）Ｎ層からなる従来被覆超硬工具においては、前記の高速重切削条件では、前記硬質被覆層の高温特性不足、並びに強度および靭性不足が原因で、摩耗進行が速く、かつチッピングも発生し易いことから、比較的短時間で使用寿命に至ることが明らかである。
上述のように、この発明の被覆超硬工具は、通常の条件での切削加工は勿論のこと、特に各種の鋼や鋳鉄などの切削加工を、高熱発生および高い機械的衝撃を伴う高速重切削条件で行なった場合にも、チッピングの発生なく、すぐれた耐摩耗性を発揮するものであるから、切削加工の省力化および省エネ化、さらに低コスト化に十分満足に対応できるものである。
【図面の簡単な説明】
【図１】この発明の被覆超硬工具を構成する硬質被覆層を形成するのに用いたアークイオンプレーティング装置を示し、（ａ）は概略平面図、（ｂ）は概略正面図である。
【図２】従来被覆超硬工具を構成する硬質被覆層を形成するのに用いた通常のアークイオンプレーティング装置の概略説明図である。
【図３】（ａ）は被覆超硬チップの概略斜視図、（ｂ）は被覆超硬チップの概略縦断面図である。
【図４】（ａ）は被覆超硬エンドミル概略正面図、（ｂ）は同切刃部の概略横断面図である。
【図５】（ａ）は被覆超硬ドリルの概略正面図、（ｂ）は同溝形成部の概略横断面図である。[0001]
BACKGROUND OF THE INVENTION
This invention has excellent high temperature hardness and heat resistance, and high strength and toughness due to its hard coating layer. Therefore, cutting of various types of steel and cast iron, especially at high speed with high heat generation and high mechanical strength. A surface-coated cemented carbide cutting tool that exhibits excellent wear resistance without the occurrence of chipping (microchips) in the hard coating layer when performed under heavy cutting conditions such as high cutting with impact and high feed ( Hereinafter, it is related to a coated carbide tool.
[0002]
[Prior art]
In general, coated carbide tools are used for throwaway inserts that are detachably attached to the tip of a cutting tool for drilling and cutting of various materials such as steel and cast iron, and for flat cutting. There are drills, miniature drills, solid type end mills used for chamfering, grooving, shoulder processing, etc. in which the cutting blade takes an intermittent cutting form, 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 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). surface, composition _{formula): (Ti 1-X Al} X) N ( provided that an atomic ratio, X is a composite nitride of Ti and Al satisfying shown) of 0.40 to 0.65 [hereinafter, ( Coated carbide tools formed by physically vapor-depositing a hard coating layer composed of a layer of Ti, Al) N] with an average layer thickness of 1 to 15 μm have been proposed for continuous cutting and intermittent cutting of various steels and cast irons. It is used.
[0004]
Furthermore, the above-mentioned coated carbide tool is, for example, the above-mentioned carbide substrate is inserted into an arc ion plating apparatus which is one type of physical vapor deposition apparatus schematically shown in FIG. For example, in a state heated to a temperature of 500 ° C., an arc discharge is generated between the anode electrode and the cathode electrode (evaporation source) in which a Ti—Al alloy having a predetermined composition is set, for example, under a current of 90 A, At the same time, nitrogen gas is introduced into the apparatus as a reaction gas to give a reaction atmosphere of, for example, 2 Pa, while the cemented carbide substrate is applied to the surface of the cemented carbide substrate with a bias voltage of, for example, −100 V applied. It is also known that it is produced by vapor-depositing a hard coating layer composed of the (Ti, Al) N layer.
[0005]
[Problems to be solved by the invention]
In recent years, the performance of cutting devices has been dramatically improved, while at the same time, there are strong demands for labor saving and energy saving and further cost reduction for cutting processing. With this, cutting is performed at high speed, with high cutting depth and high feed. Although there is a tendency for the above-mentioned conventional coated carbide tools to be used under heavy cutting conditions, there is no problem when this is used under normal cutting conditions, but the cutting process generates high heat and high mechanical impact. When performed under the accompanying high-speed heavy cutting conditions, especially the high temperature hardness and heat resistance of the hard coating layer is insufficient, and the strength and toughness are also insufficient, so the progress of wear of the hard coating layer is further promoted, In addition, since chipping is likely to occur, the service life is reached in a relatively short time.
[0006]
[Means for Solving the Problems]
In view of the above, the present inventors have developed the above-mentioned conventional coated carbide tool in order to develop a coated carbide tool that exhibits excellent chipping resistance with a hard coating layer particularly under heavy cutting conditions. As a result of conducting research with a focus on the hard coating layer,
(A) The (Ti, Al) N layer constituting the conventional coated carbide tool formed using the arc ion plating apparatus shown in FIG. 2 has a substantially uniform composition over the entire layer thickness. Therefore, it has uniform high temperature hardness and heat resistance, and further has strength and toughness. For example, arc ion plating having a structure shown in a schematic plan view in FIG. 1A and a schematic front view in FIG. An apparatus, that is, a rotating table for mounting a carbide substrate is provided at the center of the apparatus, and an Al—Ti alloy having a relatively high Al content (low Ti content) is placed on one side and the other side is sandwiched between the rotating tables. Using an arc ion plating apparatus in which a Ti-Al alloy having a relatively high Ti content (low Al content) is disposed as a cathode electrode (evaporation source) and facing the outer periphery of the rotary table of the apparatus Multiple The carbide substrate is mounted in a ring shape, and in this state, the atmosphere inside the apparatus is changed to a nitrogen atmosphere, the rotary table is rotated, and the carbide substrate itself is rotated for the purpose of uniforming the thickness of the hard coating layer formed by vapor deposition. while, by generating arc discharge between the cathode (evaporation source) and an anode electrode on both sides of the surface in (Ti, Al) of the cemented carbide substrate to form a N layer, the result (Ti , Al) In the N layer , the cemented carbide substrate arranged in a ring shape on the rotary table is a cathode electrode of an Al—Ti alloy having a relatively high Al content (a low Ti content) on the one side. At the point closest to the (evaporation source), the highest Al content point is formed in the layer, and the carbide substrate has a relatively high Ti content (low Al content) on the other side. Closest contact with alloy cathode At that time, the highest Ti content point is formed in the layer, and by rotation of the rotary table, the highest Al content point and the highest Ti content point appear alternately in the layer thickness direction along the layer thickness direction. A component concentration distribution structure in which the Al and Ti contents continuously change from the highest Al content point to the highest Ti content point and from the highest Ti content point to the highest Al content point, respectively.
[0007]
(B) In the formation of the (Ti, Al) N layer having the repeated continuous change component concentration distribution structure of (a) above, the Al content in the Al—Ti alloy which is the cathode electrode (evaporation source) on one side of the opposite arrangement The Al content in the Ti-Al alloy, which is a cathode electrode (evaporation source) on the other side, is relatively higher than the Al content of the conventional Ti-Al alloy. While making it relatively low compared to the Al content of the alloy, controlling the rotational speed of the rotary table on which the carbide substrate is mounted,
The Al highest content point is the composition formula: (Al _1-X Ti _X ) N (wherein X is 0.05 to 0.30 in atomic ratio),
The highest Ti content point is the composition formula: (Ti _1-Y Al _Y ) N (wherein Y represents 0.05 to 0.35 in atomic ratio),
And the distance in the thickness direction between the adjacent Al highest content point and Ti highest content point adjacent to each other is 0.01 to 0.1 μm,
In the Al highest content point portion, since the Al content is relatively higher than the conventional (Ti, Al) N layer described above, it shows even higher high temperature hardness and heat resistance (high temperature characteristics), On the other hand, since the Ti content is relatively higher than the conventional (Ti, Al) N layer in the Ti highest content point portion, it has higher strength and toughness, and these Al highest content points. from what has been very small interval Ti up containing point, now comprises a high temperature properties with excellent while maintaining the high strength and high toughness as a characteristic of the entire layer, therefore, the hard coating layer such a structure of the (Ti , Al) N coated carbide tool made of N layer can be used as a hard coating layer even when various types of steel and cast iron are cut under high-speed heavy cutting conditions with high heat generation and high mechanical impact. No chipping , To become to exert excellent wear resistance.
The research results shown in (a) and (b) above were obtained.
[0008]
The present invention has been made based on the above research results, and is provided with a rotating table for mounting a carbide substrate at the center of the apparatus, sandwiching the rotating table, and Al— Using an arc ion plating apparatus in which a Ti alloy and a Ti-Al alloy for forming the highest Ti content point on the other side are arranged facing each other as a cathode electrode (evaporation source), a plurality of carbide substrates are formed along the outer periphery of the rotary table. In this state, the rotary table is rotated with the atmosphere inside the apparatus as a nitrogen atmosphere, and the carbide substrate itself rotates, while the cathode electrode (evaporation source) and the anode electrode on both sides are rotated. In the coated carbide tool formed by generating an arc discharge and vapor-depositing a hard coating layer made of a (Ti, Al) N layer on the surface of the carbide substrate with an overall average layer thickness of 1 to 15 μm,
In the hard coating layer, the Al highest content point (Ti lowest content point) and the Ti highest content point (Al lowest content point) are alternately present at predetermined intervals along the layer thickness direction, and the Al From the highest content point to the Ti highest content point, from the Ti highest content point to the Al highest content point has a component concentration distribution structure in which the Al and Ti contents each continuously change,
Furthermore, the Al highest content point, the composition _{_{formula: (Al 1-X Ti X}} ) N ( provided that an atomic ratio, X is shows the 0.05 to 0.30),
The highest Ti content point is the composition formula: (Ti _1-Y Al _Y ) N (wherein Y represents 0.05 to 0.35 in atomic ratio),
And the interval between the Al highest content point and the Ti highest content point adjacent to each other is 0.01 to 0.1 μm.
It is characterized by a coated carbide tool that exhibits excellent wear resistance with a hard coating layer under high-speed heavy cutting conditions.
[0009]
Next, in the coated carbide tool of the present invention, the reason why the structure of the hard coating layer constituting the tool is limited as described above will be described.
(A) Composition of Al highest content point Al component in (Ti, Al) N of Al highest content point is contained for the purpose of improving the high temperature hardness and heat resistance (high temperature characteristics) of TiN having high strength and high toughness. Therefore, the higher the content ratio of the Al component, the higher the high temperature characteristics. However, the X value indicating the ratio of Ti accounts for 0.05% of the total amount with Al (atomic ratio). When the ratio is less than 1, the proportion of Al is relatively excessive, and even if the highest Ti content point having high strength and high toughness exists adjacently, a decrease in the strength and toughness of the layer itself is inevitable. Chipping and the like are likely to occur. On the other hand, if the X value indicating the Ti ratio exceeds 0.30, the Al ratio becomes relatively small, and the desired excellent high-temperature characteristics cannot be ensured. From that The value was defined as 0.05 to 0.30.
[0010]
(B) Composition of highest Ti content point As described above, the highest Al content point has excellent high-temperature characteristics, but on the other hand, it is inferior in strength and toughness. For the purpose, the Ti content ratio is high, whereby the highest Ti content points having high strength and high toughness are alternately interposed in the thickness direction. Therefore, the Y value indicating the ratio of Al is Ti and If the proportion (atomic ratio) in the total amount exceeds 0.35, the proportion of Al becomes relatively large, and the desired excellent strength and toughness cannot be ensured, while the proportion of Al is shown. If the Y value is also less than 0.05, the proportion of Ti is relatively increased, and it becomes impossible to provide the desired high-temperature characteristics at the highest Ti content point. .35 .
[0011]
(C) Interval between the highest Al content point and the highest Ti content point If the distance is less than 0.01 μm, it is difficult to clearly form each point with the above composition. High toughness and high temperature characteristics cannot be secured, and if the distance exceeds 0.1 μm, each point has a defect, that is, if Al is the highest content point, the strength and toughness are insufficient, and the highest Ti content point. Insufficient high temperature characteristics appear locally in the layer, and this may cause chipping on the cutting edge and promote wear progress. Therefore, the interval is set to 0.01 to 0.1 μm. Determined.
[0012]
(D) Overall average layer thickness of hard coating layer If the layer thickness is less than 1 μm, desired wear resistance cannot be ensured. On the other hand, if the average layer thickness exceeds 15 μm, chipping tends to occur. Therefore, the average layer thickness was determined to be 1 to 15 μm.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Next, the coated carbide tool of the present invention will be specifically described with reference to examples.
Example 1
As raw material powders, WC powder, TiC powder, VC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, and Co powder, all having an average particle diameter of 1 to 3 μm, were prepared. And then wet-mixed with a ball mill for 72 hours, dried, and press-molded into a green compact at a pressure of 100 MPa. The green compact was vacuumed at 6 Pa at a temperature of 1400 ° C. for 1 hour. Sintered under the holding conditions, and after sintering, the cutting edge portion was subjected to a honing process of R: 0.03, and the carbide bases A1 to A10 made of WC-based cemented carbide having ISO / CNMG120408 chip shape Formed.
[0014]
In addition, as raw material powders, all are TiCN (weight ratio TiC / TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC powder having an average particle diameter of 0.5 to 2 μm. Co powder and Ni powder are prepared, and these raw material powders are blended in the blending composition shown in Table 2, wet mixed by a ball mill for 24 hours, dried, and then pressed into a compact at a pressure of 100 MPa. The green compact was sintered in a nitrogen atmosphere of 2 kPa at a temperature of 1500 ° C. for 1 hour, and after sintering, the cutting edge portion was subjected to a honing process of R: 0.03 to obtain ISO standard / CNMG120408. TiCN-based cermet carbide substrates B1 to B6 having the following chip shape were formed.
[0015]
Next, each of the above-mentioned carbide substrates A1 to A10 and B1 to B6 is ultrasonically cleaned in acetone and dried, on the rotary table in the arc ion plating apparatus shown in FIG. Therefore, as the cathode electrode (evaporation source) on one side, the Ti-Al alloy for forming the highest Ti content point with various component compositions, and the various component compositions as the cathode electrode (evaporation source) on the other side The Al-Ti alloy for forming the highest Al content point is placed oppositely across the rotary table, and the metal Ti for bombard cleaning is also mounted. First, 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 carbide substrate rotating while rotating on the rotary table, and the gold electrode of the cathode electrode was applied. An arc discharge is generated by passing a current of 100 A between Ti and the anode electrode, thereby cleaning the surface of the carbide substrate with Ti bombardment, and then introducing nitrogen gas as a reaction gas into the apparatus to form a reaction atmosphere of 2 Pa. In addition, a DC bias voltage of −100 V is applied to a carbide substrate that rotates while rotating on the rotary table, and each cathode electrode (Ti-Al alloy for forming the highest Ti content point and Al for forming the highest Al content point) A current of 100 A flows between the Ti alloy) and the anode electrode to generate an arc discharge, so that the maximum Al of the target composition shown in Tables 3 and 4 along the layer thickness direction is formed on the surface of the carbide substrate. The content points and the highest Ti content points are alternately repeatedly present at the target intervals shown in Tables 3 and 4, and the highest Ti content point and the highest Ti content from the highest Al content point. Vapor deposition of a hard coating layer having a component concentration distribution structure in which the Al and Ti contents continuously change from the containing point to the Al highest containing point, and having the target total layer thickness shown in Tables 3 and 4 3 (a) is a schematic perspective view, and FIG. 3 (b) is a schematic longitudinal cross-sectional view of the present invention surface-coated cemented carbide throwaway tip (hereinafter, referred to as a cemented carbide tool of the present invention). 1 to 16 were manufactured.
[0016]
Further, for the purpose of comparison, these carbide substrates A1 to A10 and B1 to B6 are ultrasonically cleaned in acetone and dried, and then loaded into a normal arc ion plating apparatus shown in FIG. In addition, Ti-Al alloys with various component compositions are attached as cathode electrodes (evaporation sources), and metal Ti for bombard cleaning is also attached. First, the inside of the apparatus is evacuated and kept at a vacuum of 0.5 Pa or less. However, after heating the inside of the apparatus to 500 ° C. with a heater, a DC bias voltage of −1000 V was applied to the cemented carbide substrate, and a current of 100 A was passed between the metal Ti and the anode electrode of the cathode electrode to cause arc discharge. Thus, the surface of the carbide substrate is cleaned by Ti bombardment, and then nitrogen gas is introduced as a reaction gas into the apparatus to form a reaction atmosphere of 2 Pa. A DC bias voltage of 00 V is applied, and a current of 100 A is caused to flow between the Ti—Al alloy of the cathode electrode and the anode electrode to generate an arc discharge, thereby each of the carbide substrates A1 to A10 and B1 to B6. A hard coating layer composed of a (Ti, Al) N layer having the target composition and target layer thickness shown in Tables 5 and 6 and substantially unchanged in the layer thickness direction is deposited on the surface of Thus, conventional surface-coated cemented carbide throwaway tips (hereinafter referred to as conventional coated cemented carbide tips) 1 to 16 as conventional coated cemented carbide tools having the shape shown in FIG.
[0017]
Next, with the present invention coated carbide tips 1-16 and conventional coated carbide tips 1-16, in a state where this is screwed to the tip of the tool steel tool with a fixing jig,
Work material: JIS / SCM440 round bar,
Cutting speed: 300 m / min. ,
Incision: 4mm,
Feed: 0.15 mm / rev. ,
Cutting time: 8 minutes
Dry-type continuous high-speed high-cut cutting test of alloy steel under the conditions of
Work material: JIS · S45C lengthwise equal 4 round grooved round bars,
Cutting speed: 250 m / min. ,
Incision: 1.5mm,
Feed: 0.6 mm / rev. ,
Cutting time: 8 minutes
Dry intermittent high-speed high-feed cutting test of carbon steel under the conditions of
Work material: JIS / FC300 round bar,
Cutting speed: 400 m / min. ,
Incision: 4mm,
Feed: 0.25 mm / rev. ,
Cutting time: 8 minutes
The dry continuous high-speed, high-cut cutting test of cast iron was performed under the conditions described above, and the flank wear width of the cutting edge was measured in any cutting test. The measurement results are shown in Tables 3-6.
[0018]
[Table 1]

[0019]
[Table 2]

[0020]
[Table 3]

[0021]
[Table 4]

[0022]
[Table 5]

[0023]
[Table 6]

[0024]
(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 Prepare a powder, 2.3 μm Cr ₃ C ₂ powder, 1.5 μm VC powder, 1.0 μm (Ti, W) C powder, and 1.8 μm Co powder. Each was blended in the blending composition shown in Table 7, further added with wax, ball milled in acetone for 24 hours, dried under reduced pressure, then pressed into various compacts of a predetermined shape at a pressure of 100 MPa. The green compact is heated to a predetermined temperature in the range of 1370 to 1470 ° C. at a rate of temperature increase of 7 ° C./min in a 6 Pa vacuum atmosphere, held at this temperature for 1 hour, and then fired under furnace cooling conditions. Finally, the diameters are 8mm, 13mm, and 26 3 types of sintered carbide rod forming bodies for forming a carbide substrate of m, and further, the diameter of the cutting edge portion by the combination shown in Table 7 by grinding from the above three types of sintered rods. X Carbide substrates (end mills) C-1 to C-8 having lengths of 6 mm x 13 mm, 10 mm x 22 mm, and 20 mm x 45 mm, respectively, were produced.
[0025]
Then, these carbide substrates (end mills) C-1 to C-8 were ultrasonically washed in acetone and dried, and then charged into the arc ion plating apparatus shown in FIG. Under the same conditions as in Example 1, the Al highest content point and the Ti highest content point of the target composition shown in Table 8 along the layer thickness direction alternately and repeatedly exist at the target interval shown in Table 8, and It has a component concentration distribution structure in which the Al and Ti contents continuously change from the highest Al content point to the highest Ti content point and from the highest Ti content point to the highest Al content point, and is also shown in Table 8 By depositing a hard coating layer having a total target layer thickness, the coated carbide tool of the present invention having the shape shown in the schematic front view of FIG. 4A and the schematic cross-sectional view of the cutting edge portion in FIG. Surface coated cemented carbide of the present invention as End mill (hereinafter, the present invention refers to the coating end mills) 1-8 were prepared, respectively.
[0026]
For the purpose of comparison, the above-mentioned carbide substrates (end mills) C-1 to C-8 are ultrasonically cleaned in acetone and dried, and the ordinary arc ion plating apparatus shown in FIG. 2 is also used. (Ti, Al) N having the target composition and target layer thickness shown in Table 9 and substantially no composition change along the layer thickness direction under the same conditions as in Example 1 above. By vapor-depositing a hard coating layer consisting of layers, conventional surface-coated cemented carbide end mills (hereinafter referred to as conventional coated carbide end mills) 1 to 8 as conventional coated carbide tools were produced, respectively.
[0027]
Next, of the present invention coated carbide end mills 1-8 and conventional coated carbide end mills 1-8, the present invention coated carbide end mills 1-3 and conventional coated carbide end mills 1-3 are as follows:
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / SKD11 plate material,
Cutting speed: 150 m / min. ,
Groove depth (cut): 1.5 mm,
Table feed: 1500mm / min,
About the dry high-speed high-feed grooving cutting test of the tool steel under the conditions of the present invention, the coated carbide end mills 4-6 of the present invention and the conventional coated carbide end mills 4-6,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / SUS304 plate,
Cutting speed: 120 m / min. ,
Groove depth (cut): 7 mm,
Table feed: 600 mm / min,
For stainless steel dry high-speed and high-grooving groove cutting test, coated carbide end mills 7 and 8 of the present invention and conventional coated carbide end mills 7 and 8
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / SNCM439 plate material,
Cutting speed: 250 m / min. ,
Groove depth (cut): 6 mm
Table feed: 1000 mm / min,
In each of the groove cutting tests, the flank wear width of the outer peripheral edge of the cutting edge reaches 0.1 mm, which is a guide for the service life. The cutting groove length up to was measured. The measurement results are shown in Tables 8 and 9, respectively.
[0028]
[Table 7]

[0029]
[Table 8]

[0030]
[Table 9]

[0031]
(Example 3)
The diameters produced in Example 2 above were 8 mm (for forming carbide substrates C-1 to C-3), 13 mm (for forming carbide substrates C-4 to C-6), and 26 mm (for carbide substrates C-). 7, for C-8 formation), from these three types of round bar sintered bodies, the diameter x length of the groove forming portion is 4 mm x 13 mm (by grinding), respectively. Carbide substrates D-1 to D-3), 8 mm × 22 mm (Carbide substrates D-4 to D-6), and 16 mm × 45 mm (Carbide substrates D-7, D-8) Hard substrates (drills) D-1 to D-8 were produced, respectively.
[0032]
Next, the cutting edges of these carbide substrates (drills) D-1 to D-8 are subjected to honing, ultrasonically cleaned in acetone and dried, and the arc ion plating apparatus shown in FIG. 1 is also used. In the same conditions as in Example 1 above, the target interval shown in Table 10 in which the Al highest content point and Ti highest content point of the target composition shown in Table 10 are alternately shown along the layer thickness direction. And a component concentration distribution structure in which Al and Ti contents continuously change from the Al highest content point to the Ti highest content point, from the Ti highest content point to the Al highest content point, respectively. And by vapor-depositing the hard coating layer having the target total layer thickness shown in Table 10, the shape shown in the schematic front view in FIG. 5A and the schematic cross-sectional view of the groove forming portion in FIG. The present invention coated carbide tool and The present invention surface coating cemented carbide drills Te (hereinafter, the present invention refers to the coating carbide drills) 1-8 were prepared, respectively.
[0033]
For comparison purposes, the cutting edges of the above-mentioned carbide substrates (drills) D-1 to D-8 are honed, ultrasonically cleaned in acetone, and dried, as shown in FIG. The sample was charged into a normal arc ion plating apparatus, had the target composition and target layer thickness shown in Table 11 under the same conditions as in Example 1, and substantially changed in composition along the layer thickness direction. By depositing a hard coating layer comprising no (Ti, Al) N layer, conventional surface-coated carbide drills (hereinafter referred to as conventional coated carbide drills) 1 to 8 as conventional coated carbide tools are respectively provided. Manufactured.
[0034]
Next, of the present invention coated carbide drills 1-8 and conventional coated carbide drills 1-8, the present invention coated carbide drills 1-3 and conventional coated carbide drills 1-3,
Work material: Plane dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SKD61 plate material,
Cutting speed: 120 m / min. ,
Feed: 0.2mm / rev,
Hole depth: 8mm
With respect to the tool steel wet high-speed high-feed drilling test, the present invention coated carbide drills 4-6 and the conventional coated carbide drills 4-6,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / FCD400 plate material,
Cutting speed: 250 m / min. ,
Feed: 0.3mm / rev,
Hole depth: 16mm
For the ductile cast iron wet high-speed high-feed drilling test under the conditions of the present invention, the coated carbide drills 7 and 8 of the present invention and the conventional coated carbide drills 7 and 8,
Work material: Plane dimensions: 100 mm x 250 mm, thickness: 50 mm JIS / FC300 plate material,
Cutting speed: 200 m / min. ,
Feed: 0.4mm / rev,
Hole depth: 32mm
We performed a high-speed, high-feed, high-feed drilling test of cast iron under the above conditions, and in any wet drilling test (using water-soluble cutting oil), the flank wear width of the tip cutting edge surface reached 0.3 mm The number of holes drilled was measured. The measurement results are shown in Tables 10 and 11, respectively.
[0035]
[Table 10]

[0036]
[Table 11]

[0037]
In the hard coating layer which comprises this invention coated carbide tips 1-16, this invention coated carbide end mills 1-8, and this invention coated carbide drills 1-8 as this invention coated carbide tool obtained as a result. Composition of Al highest content point and Ti highest content point, and conventionally coated carbide tips 1-16 as conventionally coated carbide tools, conventionally coated carbide end mills 1-8, and hard coating of conventionally coated carbide drills 1-8 The composition of the layers was measured using an Auger spectroscopic analyzer, and each showed substantially the same composition as the target composition.
Further, the distance between the Al highest content point and the Ti highest content point in the hard coating layer of these coated carbide tools of the present invention, and the total layer thickness thereof, and the thickness of the hard coating layer of the conventional coated carbide tool, When the cross-section was measured using a scanning electron microscope, all showed substantially the same value as the target value.
[0038]
【The invention's effect】
From the results shown in Tables 3 to 11, the highest Al content point having excellent high temperature hardness and heat resistance and the highest Ti content point having high strength and high toughness are alternately determined in the layer thickness direction of the hard coating layer. A component concentration distribution structure that repeatedly exists at intervals, and in which the Al and Ti contents continuously change from the highest Al content point to the highest Ti content point and from the highest Ti content point to the highest Al content point, respectively. Each of the coated carbide tools of the present invention has various kinds of cutting work such as steel and cast iron under high speed conditions with high temperature generation and heavy cutting conditions such as high cutting and high feed with high mechanical impact. Even in this case, the hard coating layer exhibits excellent wear resistance without occurrence of chipping, whereas the hard coating layer has substantially no composition change along the layer thickness direction (Ti, Al) N layer. Conventional coated carbide consisting of The tool is used in a relatively short time because the high-speed heavy cutting conditions result in insufficient wear at high temperature and insufficient strength and toughness due to insufficient wear and high toughness. It is clear that it reaches the end of its life.
As described above, the coated carbide tool of the present invention is capable of cutting various types of steel and cast iron as well as cutting under normal conditions, particularly high-speed heavy cutting with high heat generation and high mechanical impact. Even when performed under conditions, chipping does not occur and excellent wear resistance is exhibited, so that it is possible to satisfactorily cope with labor saving and energy saving of cutting work and cost reduction.
[Brief description of the drawings]
FIG. 1 shows an arc ion plating apparatus used for forming a hard coating layer constituting a coated carbide tool of the present invention, wherein (a) is a schematic plan view and (b) is a schematic front view.
FIG. 2 is a schematic explanatory view of a normal arc ion plating apparatus used to form a hard coating layer constituting a conventional coated carbide tool.
FIG. 3A is a schematic perspective view of a coated carbide chip, and FIG. 3B is a schematic longitudinal sectional view of the coated carbide chip.
4A is a schematic front view of a coated carbide end mill, and FIG. 4B is a schematic cross-sectional view of the cutting edge portion.
5A is a schematic front view of a coated carbide drill, and FIG. 5B is a schematic cross-sectional view of the groove forming portion.

Claims

A rotating table for mounting either or both of a tungsten carbide base cemented carbide substrate and a titanium carbonitride-based cermet substrate is provided in the center of the apparatus, and the Al— Using an arc ion plating apparatus in which a Ti alloy and a Ti—Al alloy for forming the highest Ti content point on the other side are disposed as a cathode electrode (evaporation source), a plurality of the substrates are ringed along the outer periphery of the rotary table. In this state, an arc discharge is generated between the cathode electrode (evaporation source) and the anode electrode on both sides while rotating the rotating table with the atmosphere inside the apparatus as a nitrogen atmosphere and rotating the substrate itself. the is generated on the surface of the substrate, depositing a hard coating layer made of a composite nitride layer of Ti and Al in total average layer thickness of 1~15μm In the surface-coated cemented carbide cutting tool comprising,
In the hard coating layer, the Al highest content point (Ti lowest content point) and the Ti highest content point (Al lowest content point) are alternately present at predetermined intervals along the layer thickness direction, and the Al From the highest content point to the Al lowest content point, from the Al lowest content point to the Al highest content point has a component concentration distribution structure in which Al and Ti content continuously change,
Furthermore, the Al highest content point, the composition _{_{formula: (Al 1-X Ti X}} ) N ( provided that an atomic ratio, X is shows the 0.05 to 0.30),
The highest Ti content point is the composition formula: (Ti _1-Y Al _Y ) N (wherein Y represents 0.05 to 0.35 in atomic ratio),
The distance between the Al highest content point and the Ti highest content point adjacent to each other is 0.01 to 0.1 μm,
A surface-coated cemented carbide cutting tool that exhibits excellent wear resistance under high-speed heavy cutting conditions.