JP3981973B2

JP3981973B2 - Surface-coated cemented carbide cutting tool with excellent chipping resistance in heavy cutting of difficult-to-cut materials

Info

Publication number: JP3981973B2
Application number: JP2002106111A
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: 2002-04-09
Filing date: 2002-04-09
Publication date: 2007-09-26
Anticipated expiration: 2022-04-09
Also published as: JP2003300105A

Description

【０００１】
【発明の属する技術分野】
この発明は、硬質被覆層が高強度と高靭性を有し、かつ高温硬さと耐熱性、さらに切粉滑り性にもすぐれ、したがって特に切粉滑り性が要求されるステンレス鋼や軟鋼などの難削材の切削加工を、高い機械的衝撃を伴う高切り込みや高送りなどの重切削条件で行なった場合にも、硬質被覆層がすぐれた耐チッピング性を発揮する表面被覆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-(X+ _Ｚ ₎Ａｌ_XＶ_Ｚ］Ｎ（ただし、原子比で、Ｘは０．４０〜０．６５、Ｚ：０．０５〜０．２０を示す）を満足するＴｉとＡｌとＶの複合窒化物［以下、（Ｔｉ，Ａｌ，Ｖ）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、かかる被覆超硬工具が、硬質被覆層を構成する前記（Ｔｉ，Ａｌ，Ｖ）Ｎ層がすぐれた高温特性（高温硬さおよび耐熱性）、さらにすぐれた切粉滑り性を有することから、特に切削時に切粉が切刃表面に溶着し易いステンレス鋼や軟鋼などの難削材などの連続切削や断続切削加工に用いられることも知られている。
【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、ヒーターで装置内を、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−Ｖ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，Ｖ）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は強く、これに伴い、切削加工は高切り込みや高送りなどの重切削条件での切削加工でもすぐれた耐摩耗性を発揮する被覆超硬工具が強く求められているが、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、切削加工を高い機械的衝撃を伴う高切り込みや高送りなどの重切削条件で行なった場合には、特に硬質被覆層の強度および靭性不足が原因でチッピング（微小割れ）が発生し易くなり、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、特に重切削条件加工で硬質被覆層がすぐれた耐チッピング性を発揮する被覆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，Ｖ）Ｎ層は、層厚全体に亘って実質的に均一な組成を有し、したがって均質な高温硬さと耐熱性、および切粉滑り性を有するが、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Ａｌ成分最高含有点形成用Ｔｉ−Ａｌ−Ｖ合金、他方側にＡｌ成分不含有点形成用Ｔｉ−Ｖ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，Ｖ）Ｎ層を形成すると、この結果の（Ｔｉ，Ａｌ，Ｖ）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Ｔｉ−Ａｌ−Ｖ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成分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Ｔｉ−Ｖ合金のカソード電極に最も接近した時点で層中にＡｌ成分不含有点が形成され、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成分最高含有点とＡｌ成分不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成分最高含有点から前記Ａｌ成分不含有点、前記Ａｌ最低含有点から前記Ａｌ成分不含有点へＡｌ成分含有量が連続的に変化する成分濃度分布構造を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，Ｖ）Ｎ層において、対向配置の一方側のカソード電極（蒸発源）であるＴｉ−Ａｌ−Ｖ合金におけるＡｌおよびＶ含有量を上記の従来（Ｔｉ，Ａｌ，Ｖ）Ｎ層形成用Ｔｉ−Ａｌ−Ｖ合金のＡｌおよびＶ含有量に相当するものとし、同他方側のカソード電極（蒸発源）であるＴｉ−Ｖ合金におけるＶ含有量を前記Ｔｉ−Ａｌ−Ｖ合金のＶ含有量と同じくすると共に、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Ａｌ成分最高含有点が、組成式：［Ｔｉ_1-(X+ _Ｚ ₎Ａｌ_XＶ_Ｚ］Ｎ（ただし、原子比で、Ｘは０．４０〜０．６５、Ｚ：０．０５〜０．２０を示す）、
上記Ａｌ成分不含有点が、組成式：［Ｔｉ_1- _ＺＶ_Ｚ］Ｎ（ただし、原子比で、Ｚ：０．０５〜０．２０を示す）、
を満足し、かつ隣り合う上記Ａｌ成分最高含有点とＡｌ成分不含有点の厚さ方向の間隔を０．０１〜０．１μｍとすると、
上記Ａｌ成分最高含有点部分では、上記の従来（Ｔｉ，Ａｌ，Ｖ）Ｎ層のもつ高温硬さと耐熱性、および切粉滑り性に相当するすぐれた高温硬さと耐熱性（高温特性）、および切粉滑り性を示し、一方上記Ａｌ成分不含有点部分では、実質的にＡｌを含有しない（Ｔｉ，Ｖ）Ｎで構成されるようになるので、（Ｔｉ，Ｖ）Ｎのもつ高強度と高靭性、および切粉滑り性が確保され、かつこれらＡｌ成分最高含有点とＡｌ成分不含有点の間隔をきわめて小さくしたことから、層全体の特性としてすぐれた高温特性と切粉滑り性を保持した状態で一段とすぐれた強度と靭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，Ｖ）Ｎ層からなる被覆超硬工具は、特に切粉滑り性が要求されるステンレス鋼や軟鋼などの難削材などの切削加工を、高い機械的衝撃を伴う高切り込みや高送りなどの重切削条件で行なった場合にも、硬質被覆層がすぐれた耐チッピング性を発揮するようになること。
以上（ａ）および（ｂ）に示される研究結果を得たのである。
【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成分最高含有点形成用Ｔｉ−Ａｌ−Ｖ合金、他方側にＡｌ成分不含有点形成用Ｔｉ−Ｖ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、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、（Ｔｉ，Ａｌ，Ｖ）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、層厚方向にそって、Ａｌ成分最高含有点とＡｌ成分不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成分最高含有点から前記Ａｌ成分不含有点、前記Ａｌ成分不含有点から前記Ａｌ成分最高含有点へＡｌ成分含有量が連続的に変化する成分濃度分布構造を有し、
さらに、上記Ａｌ成分最高含有点が、組成式：［Ｔｉ_1-(X+ _Ｚ ₎Ａｌ_XＶ_Ｚ］Ｎ（ただし、原子比で、Ｘは０．４０〜０．６５、Ｚ：０．０５〜０．２０を示す）、
上記Ａｌ成分不含有点が、組成式：［Ｔｉ_1- _ＺＶ_Ｚ］Ｎ（ただし、原子比で、Ｚ：０．０５〜０．２０を示す）、
を満足し、かつ隣り合う上記Ａｌ成分最高含有点とＡｌ成分不含有点の間隔が、０．０１〜０．１μｍである、
難削材の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成分最高含有点の組成
Ａｌ成分最高含有点の（Ｔｉ，Ａｌ，Ｖ）ＮにおけるＡｌ成分には、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）を向上させる作用があり、また、同Ｖ成分には、切削中に高温となった切刃部において他の構成成分であるＴｉやＡｌ成分に優先して酸化（選択酸化）して、酸化バナジウム（以下、Ｖ₂Ｏ₅で示す）を生成し、このＶ₂Ｏ₅はすぐれた潤滑性を発揮することから、特にきわめて粘性の高いステンレス鋼や軟鋼などの難削材などの切削で問題となる切刃部表面への切粉の溶着現象がなくなり、すぐれた切粉滑り性が発揮され、切刃部のチッピング発生が抑制されるようになる作用があり、したがってＡｌ成分の含有割合を示すＸ値がＴｉとＶの合量に占める割合（原子比）で０．４０未満では、前記高温特性に所望の向上効果が得られず、一方同Ｘ値が０．６５を越えると、高強度および高靭性を有する（Ｔｉ，Ｖ）Ｎ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、さらにＶ成分の含有割合を示すＺ値がＴｉとＡｌの合量に占める割合（原子比）で０．０５未満では、切粉滑り性に所望の向上効果が得られず、一方同Ｚ値が０．２０を越えると、硬質被覆層の酸化が急激に進行し、摩耗が促進されるようになることから、Ｘ値を０．４０〜０．６５、Ｚ値を０．０５〜０．２０と定めた。
【００１０】
（ｂ）Ａｌ成分不含有点の組成
Ａｌ成分不含有点の（Ｔｉ，Ｖ）ＮにおけるＶ成分は、高強度および高靭性を有するＴｉＮに、上記の通り特に難削材切粉の切刃部表面への溶着を抑制し、もって耐チッピング性の向上に寄与する目的で含有するものであり、したがってＺ値が０．０５未満では所望の切粉滑り性向上効果が得られず、一方Ｚ値が０．２０を越えるとＡｌ成分不含有点での強度および靭性に低下傾向が現れ、チッピングが発生し易くなるばかりでなく、上記の通り硬質被覆層の酸化が急激に進行し、摩耗が促進されるようになることから、Ｚ値を０．０５〜０．２０と定めた。
【００１１】
（ｃ）Ａｌ成分最高含有点とＡｌ成分不含有点間の間隔
その間隔が０．０１μｍ未満ではそれぞれの点を上記の組成で明確に形成することが困難であり、この結果硬質被覆層に所望の高温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Ａｌ成分最高含有点であれば強度および靭性不足、Ａｌ成分不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１〜３μＸ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基超硬合金製のチップ超硬基体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系サーメット製のチップ超硬基体Ｂ−１〜Ｂ−６を形成した。
【００１５】
ついで、上記の超硬基体Ａ−１〜Ａ−１０およびＢ−１〜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Ａｌ成分最高含有点形成用Ｔｉ−Ａｌ−Ｖ合金、他方側のカソード電極（蒸発源）としてＡｌ成分不含有点形成用Ｔｉ−Ｖ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Ａｌ成分最高含有点形成用Ｔｉ−Ａｌ−Ｖ合金およびＡｌ成分不含有点形成用Ｔｉ−Ｖ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成分最高含有点とＡｌ成分不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成分最高含有点から前記Ａｌ成分不含有点、前記Ａｌ成分不含有点から前記Ａｌ成分最高含有点へＡｌ成分含有量が連続的に変化する成分濃度分布構造を有し、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Ａ−１〜Ａ−１０およびＢ−１〜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Ｔｉ−Ａｌ−Ｖ合金を装着し、またボンバート洗浄用金属Ｔｉも装着し、まず、装置内を排気して０．５Ｐａ以下の真空に保持しながら、ヒーターで装置内を５００℃に加熱した後、前記超硬基体に−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、前記超硬基体に印加するバイアス電圧を−１００Ｖに下げて、前記カソード電極とアノード電極との間にアーク放電を発生させ、もって前記超硬基体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，Ｖ）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・ＳＵＳ３０４の丸棒、
切削速度：１００ｍ／ｍｉｎ．、
切り込み：４ｍｍ、
送り：０．１５ｍｍ／ｒｅｖ．、
切削時間：１０分、
の条件でのステンレス鋼の乾式連続高切り込み切削加工試験、
被削材：ＪＩＳ・ＳＵＳ３０４の長さ方向等間隔４本縦溝入り丸棒、
切削速度：８０ｍ／ｍｉｎ．、
切り込み：１．５ｍｍ、
送り：０．５ｍｍ／ｒｅｖ．、
切削時間：５分、
の条件でのステンレス鋼の乾式断続高送り切削加工試験、さらに、
被削材：ＪＩＳ・Ｓ１０Ｃの丸棒、
切削速度：２５０ｍ／ｍｉｎ．、
切り込み：４ｍｍ、
送り：０．２ｍｍ／ｒｅｖ．、
切削時間：１０分、
の条件での軟鋼の乾式連続高切り込み切削加工試験を行い、いずれの切削加工試験でも切刃の逃げ面摩耗幅を測定した。この測定結果を表７に示した。
【００１８】
【表１】

【００１９】
【表２】

【００２０】
【表３】

【００２１】
【表４】

【００２２】
【表５】

【００２３】
【表６】

【００２４】
【表７】

【００２５】
（実施例２）
原料粉末として、平均粒径：５．５μｍを有する中粗粒ＷＣ粉末、同０．８μｍの微粒ＷＣ粉末、同１．３μｍのＴａＣ粉末、同１．２μｍのＮｂＣ粉末、同１．２μｍのＺｒＣ粉末、同２．３μｍのＣｒ₃Ｃ₂粉末、同１．５μｍのＶＣ粉末、同１．０μｍの（Ｔｉ，Ｗ）Ｃ粉末、および同１．８μｍのＣｏ粉末を用意し、これら原料粉末をそれぞれ表８に示される配合組成に配合し、さらにワックスを加えてアセトン中で２４時間ボールミル混合し、減圧乾燥した後、１００ＭＰａの圧力で所定形状の各種の圧粉体にプレス成形し、これらの圧粉体を、６Ｐａの真空雰囲気中、７℃／分の昇温速度で１３７０〜１４７０℃の範囲内の所定の温度に昇温し、この温度に１時間保持後、炉冷の条件で焼結して、直径が８ｍｍ、１３ｍｍ、および２６ｍｍの３種の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種の丸棒焼結体から、研削加工にて、表８に示される組み合せで、切刃部の直径×長さがそれぞれ６ｍｍ×１３ｍｍ、１０ｍｍ×２２ｍｍ、および２０ｍｍ×４５ｍｍの寸法をもったエンドミル超硬基体をそれぞれ製造した。
【００２６】
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９に示される目標組成のＡｌ成分最高含有点とＡｌ成分不含有点とが交互に同じく表９に示される目標間隔で繰り返し存在し、かつ前記Ａｌ成分最高含有点から前記Ａｌ成分不含有点、前記Ａｌ成分不含有点から前記Ａｌ成分最高含有点へＡｌ成分含有量が連続的に変化する成分濃度分布構造を有し、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、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。
【００２７】
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１０に示される目標組成および目標層厚を有し、かつ層厚方向に沿って実質的に組成変化のない（Ｔｉ，Ａｌ，Ｖ）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。
【００２８】
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・Ｓ１０Ｃの板材、
切削速度：１００ｍ／ｍｉｎ．、
溝深さ（切り込み）：５ｍｍ、
テーブル送り：５００ｍｍ／分、
の条件での軟鋼の乾式高切り込み溝切削加工試験、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：４０ｍ／ｍｉｎ．、
溝深さ（切り込み）：５ｍｍ、
テーブル送り：１００ｍｍ／分、
の条件でのステンレス鋼の乾式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・ＳＵＳ３１６の板材、
切削速度：４０ｍ／ｍｉｎ．、
溝深さ（切り込み）：５ｍｍ、
テーブル送り：７０ｍｍ／分、
の条件でのステンレス鋼の乾式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０．１ＸＸに至るまでの切削溝長を測定した。この測定結果を表９、１０にそれぞれ示した。
【００２９】
【表８】

【００３０】
【表９】

【００３１】
【表１０】

【００３２】
（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種の丸棒焼結体を用い、この３種の丸棒焼結体から、研削加工にて、表８に示される組み合せで、溝形成部の直径×長さがそれぞれ４ｍｍ×１３ｍｍ、８ｍｍ×２２ｍｍ、および１６ｍｍ×４５ｍｍの寸法をもったドリル超硬基体をそれぞれ製造した。
【００３３】
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１１に示される目標組成のＡｌ成分最高含有点とＡｌ成分不含有点とが交互に同じく表１１に示される目標間隔で繰り返し存在し、かつ前記Ａｌ成分最高含有点から前記Ａｌ成分不含有点、前記Ａｌ成分不含有点から前記Ａｌ成分最高含有点へＡｌ成分含有量が連続的に変化する成分濃度分布構造を有し、かつ同じく表１１に示される目標全体層厚の硬質被覆層を蒸着することにより、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。
【００３４】
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１２に示される目標組成および目標層厚を有し、かつ層厚方向に沿って実質的に組成変化のない（Ｔｉ，Ａｌ，Ｖ）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。
【００３５】
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・ＳＵＳ３０４の板材、
切削速度：２０ｍ／ｍｉｎ．、
送り：０．２５ｍｍ／ｒｅｖ、
穴深さ：４ｍｍ、
の条件でのステンレス鋼の湿式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・Ｓ１０Ｃの板材、
切削速度：６０ｍ／ｍｉｎ．、
送り：０．４ｍｍ／ｒｅｖ、
穴深さ：８ｍｍ、
の条件での軟鋼の湿式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・ＳＵＳ３１６の板材、
切削速度：３５ｍ／ｍｉｎ．、
送り：０．３５ｍｍ／ｒｅｖ、
穴深さ：１６ｍｍ、
の条件でのステンレス鋼の湿式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０．３ＸＸに至るまでの穴あけ加工数を測定した。この測定結果を表１１、１２にそれぞれ示した。
【００３６】
【表１１】

【００３７】
【表１２】

【００３８】
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成分最高含有点とＡｌ成分不含有点の組成、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成分最高含有点とＡｌ成分不含有点間の間隔、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。
【００３９】
【発明の効果】
表３〜１２に示される結果から、硬質被覆層が層厚方向に、すぐれた高温硬さと耐熱性、さらに切粉滑り性を有するＡｌ成分最高含有点と高強度と高靭性、さらに切粉滑り性を有するＡｌ成分不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成分最高含有点から前記Ａｌ成分不含有点、前記Ａｌ成分不含有点から前記Ａｌ成分最高含有点へＡｌ成分含有量が連続的に変化する成分濃度分布構造を有する本発明被覆超硬工具はいずれも、粘性が高く、切粉が切刃表面に溶着し易いステンレス鋼や軟鋼などの難削材の切削加工を、高い機械的衝撃を伴う高切り込みや高送りなどの重切削条件で行なった場合にも、硬質被覆層がすぐれた耐チッピング性を発揮するのに対して、硬質被覆層が層厚方向に沿って実質的に組成変化のない（Ｔｉ，Ａｌ，Ｖ）Ｎ層からなる従来被覆超硬工具においては、前記硬質被覆層がすぐれた高温硬さと耐熱性、さらに切粉滑り性を有するものの、強度および靭性に劣るものであるために、チッピングが発生し、これが原因で比較的短時間で使用寿命に至ることが明らかである。
上述のように、この発明の被覆超硬工具は、通常の条件での切削加工は勿論のこと、特にステンレス鋼や軟鋼などの難削材などの切削加工を、高い機械的衝撃を伴う高切り込みや高送りなどの重切削条件で行なった場合にも、すぐれた耐チッピング性を発揮し、長期に亘ってすぐれた耐摩耗性を示すものであるから、切削加工の省力化および省エネ化、さらに低コスト化に十分満足に対応できるものである。
【図面の簡単な説明】
【図１】この発明の被覆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
In the present invention, the hard coating layer has high strength and high toughness, and also has high-temperature hardness and heat resistance, and also has excellent chip slipperiness. A surface-coated cemented carbide cutting tool that provides excellent chipping resistance even when cutting the workpiece under heavy cutting conditions such as high cutting with high mechanical impact and high feed. (Hereinafter referred to as 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. Also, the throwaway tip is detachably attached and cutting is performed in the same way as the solid type end mill Throwaway end mill tools are 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: [Ti 1- (X + Z}} ) Al X V Z] N ( provided that an atomic ratio, X is from .40 to 0.65, Z: shows the 0.05-0.20 Coated carbide formed by physical vapor deposition of a hard coating layer composed of a composite nitride of Ti, Al, and V (hereinafter referred to as (Ti, Al, V) N) satisfying the above A tool has been proposed, and such a coated carbide tool has excellent high-temperature characteristics (high-temperature hardness and heat resistance) and excellent chip slipperiness in the (Ti, Al, V) N layer constituting the hard coating layer. Therefore, stainless steel and soft materials that are easy to weld chips to the cutting edge surface, especially during cutting. It is also known to be used for continuous cutting and intermittent cutting of difficult-to-cut materials such as steel.
[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 a Ti—Al—V alloy having a predetermined composition is set, for example, at a current of 90 A, while being heated to a temperature of 500 ° C. At the same time, nitrogen gas is introduced into the apparatus as a reaction gas to form a reaction atmosphere of, for example, 2 Pa, while the cemented carbide substrate has a surface of the cemented carbide substrate under the condition that a bias voltage of, for example, −100 V is applied. In addition, it is also known to be produced by vapor-depositing a hard coating layer composed of the (Ti, Al, V) N layer.
[0005]
[Problems to be solved by the invention]
In recent years, the performance of cutting machines has been dramatically improved, while on the other hand, there is a strong demand for labor saving and energy saving and further cost reduction for cutting, and as a result, cutting is performed under heavy cutting conditions such as high cutting and high feed. Although there is a strong demand for coated carbide tools that exhibit excellent wear resistance even in the cutting process, there is no problem in using the above conventional coated carbide tools under normal cutting conditions. However, when cutting is performed under heavy cutting conditions such as high cutting with high mechanical impact and high feed, chipping (microcracking) is likely to occur due to insufficient strength and toughness of the hard coating layer. At present, 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 in heavy cutting condition processing. As a result of conducting research with a focus on the hard coating layer,
(A) The (Ti, Al, V) N layer constituting the conventional coated carbide tool formed using the arc ion plating apparatus shown in FIG. 2 is substantially uniform over the entire layer thickness. For example, an arc having a structure shown in FIG. 1 (a) in a schematic plan view and in FIG. 1 (b) in a schematic front view. An ion plating apparatus, that is, a rotating table for mounting a cemented carbide substrate is provided at the center of the apparatus, and the Ti-Al-V alloy for forming the highest Al content point is formed on one side and the Al component is not present on the other side. Using an arc ion plating apparatus in which all of the contained point forming Ti-V alloys are arranged facing each other as a cathode electrode (evaporation source), a plurality of carbide substrates are formed in a ring shape along the outer periphery of the rotary table of the apparatus. Wearing 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. When an arc discharge is generated between the evaporation source) and the anode electrode to form a (Ti, Al, V) N layer on the surface of the cemented carbide substrate, the resulting (Ti, Al, V) N layer Indicates that when the carbide substrate arranged in a ring shape on the rotary table is closest to the cathode electrode (evaporation source) of the Ti-Al-V alloy on one side, the highest Al component content point is present in the layer. When the cemented carbide substrate is closest to the cathode electrode of the Ti-V alloy on the other side, an Al component-free point is formed in the layer. Before along the thickness direction The Al component highest content point and the Al component non-content point appear alternately and at predetermined intervals, and the Al component from the Al component highest content point to the Al component non-contained point and from the Al minimum content point to the Al component non-contained point To have a component concentration distribution structure whose content changes continuously.
[0007]
(B) In the (Ti, Al, V) N layer having the repeated continuous change component concentration distribution structure of (a) above, Al and Ti in the Ti—Al—V alloy which is a cathode electrode (evaporation source) on one side facing each other The V content corresponds to the Al and V contents of the above-described conventional (Ti, Al, V) N layer forming Ti—Al—V alloy, and Ti— which is the cathode electrode (evaporation source) on the other side. While making the V content in the V alloy the same as the V content of the Ti-Al-V alloy, controlling the rotation speed of the turntable on which the carbide substrate is mounted,
The Al component maximum content point, composition _{_{formula: [Ti 1- (X + Z}} ) Al X V Z] N ( provided that an atomic ratio, X is from 0.40 to 0.65, Z: from 0.05 to 0. 20)
The Al component-free point, the composition _{_{_{formula: [Ti 1- Z V Z]}}} N ( provided that an atomic ratio, Z: shows the 0.05-0.20)
And the interval in the thickness direction of the adjacent Al component highest content point and Al component non-contained point adjacent to each other is 0.01 to 0.1 μm,
In the Al component highest content point portion, the high temperature hardness and heat resistance of the conventional (Ti, Al, V) N layer, and the excellent high temperature hardness and heat resistance (high temperature characteristics) corresponding to the chip slipping property, and On the other hand, the above-mentioned Al component-free point portion is composed of (Ti, V) N that does not substantially contain Al, so that (Ti, V) N has high strength and High toughness and chip slipperiness are ensured, and the distance between the highest Al component content point and Al component non-contained point is extremely small, maintaining excellent high-temperature characteristics and chip slipperiness as the overall layer characteristics. In such a state, the coated carbide tool composed of the (Ti, Al, V) N layer having such a structure with the hard coating layer is particularly required to have chip slipperiness. Difficult to cut stainless steel or mild steel The cutting of such, even when conducted in heavy cutting conditions such as high cut and high feed with high mechanical shock, be like exhibits chipping resistance of the hard coating layer has excellent.
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 carbide substrate mounting rotary table at the center of the apparatus, sandwiching the rotary table, and having Al component highest content point forming Ti on one side. -Using an arc ion plating apparatus in which an Al-V alloy and a Ti-V alloy for forming an Al component-free point on the other side are arranged as a cathode electrode (evaporation source) opposite to each other, along the outer periphery of the rotary table of the apparatus A plurality of carbide substrates are mounted in a ring shape, and in this state, the rotary table is rotated with the atmosphere inside the apparatus being a nitrogen atmosphere, and the carbide substrates themselves are rotated, while the cathode electrodes (evaporation sources) on both sides are rotated. ) and by generating arc discharge between the anode electrode, the surface of the carbide substrate, (Ti, Al, V) deposited hard layer consisting of N layers in overall average layer thickness of 1~15μm And to become Te-coated carbide tools,
The hard coating layer has an Al component highest content point and an Al component non-contained point alternately and repeatedly at predetermined intervals along the layer thickness direction, and the Al component is not contained from the highest Al component content point. Point, having a component concentration distribution structure in which the Al component content continuously changes from the Al component-free point to the Al component highest-containing point,
Furthermore, the Al component maximum content point, composition _{_{formula: [Ti 1- (X + Z}} ) Al X V Z] N ( provided that an atomic ratio, X is from 0.40 to 0.65, Z: 0.05 to 0.20),
The Al component-free point, the composition _{_{_{formula: [Ti 1- Z V Z]}}} N ( provided that an atomic ratio, Z: shows the 0.05-0.20)
And the interval between adjacent Al component highest content point and Al component non-contained point is 0.01 to 0.1 μm,
It is characterized by a coated cemented carbide tool that exhibits excellent chipping resistance under hard coating conditions for difficult-to-cut materials.
[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 component highest content point The Al component in (Ti, Al, V) N having the highest Al component content has high temperature hardness and heat resistance (high temperature characteristics) of TiN having high strength and high toughness. In addition, the V component is oxidized (selective oxidation) in preference to Ti and Al components, which are other constituents, at the cutting edge that has become high temperature during cutting, and vanadium oxide ( (Hereinafter referred to as V ₂ O ₅ ), and this V ₂ O ₅ exhibits excellent lubricity, which is particularly problematic in cutting difficult-to-cut materials such as extremely viscous stainless steel and mild steel. There is no effect of chip welding on the surface of the cutting edge, excellent chip slipperiness is exhibited, and the chipping generation of the cutting edge is suppressed, and thus X indicating the content ratio of the Al component The ratio of the value to the total amount of Ti and V (original If the ratio is less than 0.40, the desired improvement effect cannot be obtained in the high temperature characteristics. On the other hand, if the X value exceeds 0.65, (Ti, V) N points having high strength and high toughness are adjacent to each other. Even if it exists, the strength and toughness of the layer itself are inevitably lowered, and as a result, chipping or the like is likely to occur, and the Z value indicating the content ratio of the V component accounts for the total amount of Ti and Al ( If the atomic ratio is less than 0.05, the desired improvement effect on chip slipperiness cannot be obtained. On the other hand, if the Z value exceeds 0.20, the oxidation of the hard coating layer proceeds rapidly and the wear is accelerated. Therefore, the X value was set to 0.40 to 0.65, and the Z value was set to 0.05 to 0.20.
[0010]
(B) Composition of Al component-free point V component in (Ti, V) N of Al component-free point is TiN having high strength and high toughness, especially as described above, cutting edge portion of difficult-to-cut material chips. It is contained for the purpose of suppressing welding to the surface and thus contributing to the improvement of chipping resistance. Therefore, if the Z value is less than 0.05, the desired chip slippage improving effect cannot be obtained, while the Z value is When the value exceeds 0.20, the strength and toughness at the Al component-free point tend to be reduced, and not only chipping is likely to occur, but also the oxidation of the hard coating layer proceeds rapidly as described above, and the wear is promoted. Therefore, the Z value was determined to be 0.05 to 0.20.
[0011]
(C) Interval between Al component highest content point and Al component non-content point If the distance is less than 0.01 μm, it is difficult to form each point clearly with the above composition. The high temperature characteristics, strength and toughness cannot be ensured, and if the distance exceeds 0.1 μm, the disadvantages of each point, that is, if the Al component is the highest content point, insufficient strength and toughness, Al component not contained If it is a point, insufficient high-temperature characteristics appear locally in the layer, and this makes it easy for chipping to occur or promotes the progress of wear, so the interval is 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, 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.
[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 each having an average particle diameter of 1 to 3 μX 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 holding conditions, and after sintering, the cutting edge portion is subjected to a honing process of R: 0.03, and a chip cemented carbide substrate A1 made of a WC-based cemented carbide having a chip shape of ISO standard CNMG120408 A10 was 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. Chip carbide substrates B-1 to B-6 made of TiCN cermet having the following chip shape were formed.
[0015]
Next, each of the above-mentioned carbide substrates A-1 to A-10 and B-1 to B-6 was ultrasonically cleaned in acetone and dried, and then in the arc ion plating apparatus shown in FIG. The Ti-Al-V alloy for forming the highest point of Al component having various component compositions as the cathode electrode (evaporation source) on one side along the outer periphery, the cathode electrode on the other side As an (evaporation source), an Al component-free point-forming Ti-V alloy is placed opposite to the rotary table, and a bombard cleaning metal Ti is also mounted. First, the apparatus is evacuated to 0.5 Pa or less. While maintaining the vacuum, the inside of the apparatus was heated to 500 ° C. with a heater, and then a −1000 V DC bias voltage was applied to the carbide substrate rotating while rotating on the rotary table, and the metal Ti of the cathode electrode and A current of 100 A is allowed to flow between the node electrode and arc discharge to generate Ti bombard cleaning of the carbide substrate surface, and then nitrogen gas is introduced into the apparatus as a reaction gas to form a reaction atmosphere of 2 Pa. A -100V DC bias voltage is applied to the carbide substrate rotating while rotating on the rotary table, and each cathode electrode (the Ti-Al-V alloy for forming the Al component highest content point and the Al component-free point formation) is applied. An arc discharge is generated by flowing a current of 100 A between the Ti-V alloy) and the anode electrode, so that the target composition shown in Tables 3 and 4 along the layer thickness direction is formed on the surface of the cemented carbide substrate. Al component highest content point and Al component non-contained point are alternately repeatedly present at the target intervals shown in Tables 3 and 4, and from the Al component highest content point, the Al component non-contained point, A hard coating layer having a component concentration distribution structure in which the Al component content continuously changes from the Al component non-containing point to the Al component highest containing point, and having a target total layer thickness also shown in Tables 3 and 4 The surface-coated cemented carbide throwaway tip of the present invention as a coated carbide tool of the present invention having the shape shown in the schematic perspective view of FIG. 3A and the schematic vertical sectional view of FIG. 1 to 16 (hereinafter referred to as the present coated carbide chip) were produced.
[0016]
For comparison purposes, these carbide substrates A-1 to A-10 and B -1 to B-6 were ultrasonically cleaned in acetone and dried, and each of the ordinary arcs shown in FIG. Insert the Ti-Al-V alloy with various component compositions as the cathode electrode (evaporation source) and install the bombard cleaning metal Ti as the cathode electrode (evaporation source). The inside of the apparatus was heated to 500 ° C. with a heater while maintaining a vacuum of 0.5 Pa or less, and then a −1000 V DC bias voltage was applied to the cemented carbide substrate, so that the metal Ti of the cathode electrode and the anode electrode A current of 100 A was passed between them to generate an arc discharge, thereby cleaning the surface of the carbide substrate with Ti bombardment, and then introducing nitrogen gas as a reaction gas into the apparatus to obtain a reaction atmosphere of 2 Pa. The bias voltage applied to the cemented carbide substrate is lowered to −100 V, and arc discharge is generated between the cathode electrode and the anode electrode, so that the surface of each of the cemented carbide substrates A1 to A10 and B1 to B6 is displayed on the surface. By vapor-depositing a hard coating layer composed of a (Ti, Al, V) N layer having a target composition and a target layer thickness shown in 5 and 6 and having substantially no composition change along the layer thickness direction, Similarly, conventional surface-coated cemented carbide throwaway tips (hereinafter referred to as conventional coated carbide tips) 1 to 16 as conventional coated carbide tools having the shape shown in FIG. 3 were produced.
[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 / SUS304 round bar,
Cutting speed: 100 m / min. ,
Incision: 4mm,
Feed: 0.15 mm / rev. ,
Cutting time: 10 minutes,
Stainless steel dry continuous high cutting cutting test under the conditions of
Work material: JIS / SUS304 lengthwise equidistant four round grooved round bars,
Cutting speed: 80 m / min. ,
Incision: 1.5mm,
Feed: 0.5 mm / rev. ,
Cutting time: 5 minutes
Stainless steel dry interrupted high-feed cutting test under the conditions of
Work material: JIS / S10C round bar,
Cutting speed: 250 m / min. ,
Incision: 4mm,
Feed: 0.2 mm / rev. ,
Cutting time: 10 minutes,
The dry continuous high-cut cutting test of mild steel under the conditions described above was conducted, and the flank wear width of the cutting edge was measured in any cutting test. The measurement results are shown in Table 7.
[0018]
[Table 1]

[0019]
[Table 2]

[0020]
[Table 3]

[0021]
[Table 4]

[0022]
[Table 5]

[0023]
[Table 6]

[0024]
[Table 7]

[0025]
(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 8, further added with wax, mixed with ball mill in acetone for 24 hours, dried under reduced pressure, and 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 Three carbide substrate for forming a round bar sintered C-1 through C-8 of the m forming, further from three round bar sintered body of said at grinding, the combination shown in Table 8 Thus, end mill cemented carbide substrates each having a diameter × length of the cutting edge portion of 6 mm × 13 mm, 10 mm × 22 mm, and 20 mm × 45 mm were manufactured.
[0026]
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 Al component highest content point and Al component non-contained point of the target composition shown in Table 9 along the thickness direction alternately and repeatedly exist at the target interval shown in Table 9, and from the Al component highest content point Al component non-contained point, having a component concentration distribution structure in which the Al component content continuously changes from the Al component non-contained point to the Al component highest content point, and also having the target total layer thickness shown in Table 9 By depositing a hard coating layer, the surface of the present invention as a coated carbide tool of the present invention having a shape shown in a schematic front view in FIG. 4 (a) and in a schematic cross-sectional view of the cutting edge portion in FIG. 4 (b). Coated cemented carbide end mill ( Under the present invention refers to the coating end mills) 1-8 were prepared, respectively.
[0027]
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 a (Ti, Al, V) N layer having the target composition and target layer thickness shown in Table 10 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 8 as conventional coated cemented carbide tools were produced, respectively.
[0028]
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 / S10C plate,
Cutting speed: 100 m / min. ,
Groove depth (cut): 5 mm,
Table feed: 500 mm / min,
About the dry high cutting groove cutting test of mild 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: 40 m / min. ,
Groove depth (cut): 5 mm,
Table feed: 100 mm / min,
With respect to the dry high-grooving groove cutting test of stainless steel under the following conditions, the coated carbide end mills 7 and 8 of the present invention and the conventional coated carbide end mills 7 and 8:
Work material: Plane size: 100 mm × 250 mm, thickness: 50 mm JIS / SUS316 plate material,
Cutting speed: 40 m / min. ,
Groove depth (cut): 5 mm,
Table feed: 70 mm / min,
Stainless steel dry high feed grooving cutting test under the above conditions was conducted, and in each grooving cutting test, the flank wear width of the outer peripheral edge of the cutting edge reached 0.1XX, which is a guide for the service life The cutting groove length of was measured. The measurement results are shown in Tables 9 and 10, respectively.
[0029]
[Table 8]

[0030]
[Table 9]

[0031]
[Table 10]

[0032]
(Example 3)
Using the three types of round bar sintered bodies having diameters of 8 mm, 13 mm, and 26 mm manufactured in Example 2 above, the combinations shown in Table 8 were obtained by grinding from these three types of round bar sintered bodies. Thus, drilled carbide substrates each having a diameter × length of the groove forming portion of 4 mm × 13 mm, 8 mm × 22 mm, and 16 mm × 45 mm were manufactured .
[0033]
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. And the Al component highest content point and Al component non-contained point of the target composition shown in Table 11 along the layer thickness direction alternately and repeatedly exist at the target interval shown in Table 11, and It has a component concentration distribution structure in which the Al component content continuously changes from the Al component highest content point to the Al component non-contained point, and from the Al component non-contained point to the Al component highest content point. By depositing a hard coating layer having a target overall layer thickness shown in FIG. 5A, a schematic front view is shown in FIG. 5A and a schematic cross-sectional view of the groove forming portion is shown in FIG. 5B. Invention table as a hard tool Coated cemented carbide drills (hereinafter, the present invention refers to the coating carbide drills) 1-8 were prepared, respectively.
[0034]
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 target layer thickness shown in Table 12 and substantially no composition change along the layer thickness direction (Ti, Al, V) N Conventional surface-coated cemented carbide drills (hereinafter referred to as conventional coated carbide drills) 1 to 8 as conventional coated carbide tools were produced by vapor-depositing a hard coating layer composed of layers.
[0035]
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 dimension: 100 mm × 250 mm, thickness: 50 mm JIS / SUS304 plate,
Cutting speed: 20 m / min. ,
Feed: 0.25mm / rev,
Hole depth: 4mm
For the wet high feed drilling test of stainless steel under the conditions of the present invention, the coated carbide drills 4-6 of the present invention and the conventional coated carbide drills 4-6,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / S10C plate,
Cutting speed: 60 m / min. ,
Feed: 0.4mm / rev,
Hole depth: 8mm,
About the wet high feed drilling test of mild steel 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 size: 100 mm × 250 mm, thickness: 50 mm JIS / SUS316 plate material,
Cutting speed: 35 m / min. ,
Feed: 0.35mm / rev,
Hole depth: 16mm,
Stainless steel wet high-feed drilling test under the above conditions is performed, and the flank wear width of the tip cutting edge surface reaches 0.3XX in any wet drilling test (using water-soluble cutting oil). The number of holes drilled was measured. The measurement results are shown in Tables 11 and 12, respectively.
[0036]
[Table 11]

[0037]
[Table 12]

[0038]
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 component highest content point and Al component non-contained point, as well as conventional coated carbide tips 1-16, conventional coated carbide end mills 1-8 as conventional coated carbide tools, and conventional coated carbide drills 1-8 When the composition of the hard coating layer was measured using an Auger spectroscopic analyzer, the composition was substantially the same as the target composition.
Further, the distance between the Al component highest content point and the Al component non-contained 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.
[0039]
【The invention's effect】
From the results shown in Tables 3 to 12, the hard coating layer has excellent high-temperature hardness and heat resistance in the layer thickness direction, and also has the highest Al component content, high strength and high toughness, and chip slippage. Al component-free points having the property alternately exist at predetermined intervals, and from the Al component highest content point to the Al component-free point, from the Al component-free point to the Al component highest content point All of the coated carbide tools of the present invention having a component concentration distribution structure in which the Al component content changes continuously have high viscosity and are difficult to cut materials such as stainless steel and mild steel, in which chips are likely to be welded to the surface of the cutting edge. Even when cutting is performed under heavy cutting conditions such as high cutting and high feed with high mechanical impact, the hard coating layer exhibits excellent chipping resistance, whereas the hard coating layer has a layer thickness. Of compositional change along the direction In the conventional coated carbide tool composed of a (Ti, Al, V) N layer, the hard coating layer has excellent high-temperature hardness and heat resistance, and also has a chip sliding property, but is inferior in strength and toughness. Therefore, it is clear that chipping occurs, and this causes a service life in a relatively short time.
As described above, the coated carbide tool of the present invention is capable of cutting not only under normal conditions but also cutting of difficult-to-cut materials such as stainless steel and mild steel, etc. with high mechanical impact. Even under heavy cutting conditions such as high feed rate and high feed, it exhibits excellent chipping resistance and excellent wear resistance over a long period of time. It can cope with cost reduction sufficiently satisfactorily.
[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.
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 turning table for mounting either or both of a tungsten carbide base cemented carbide substrate and a titanium carbonitride-based cermet substrate is provided at the center of the apparatus, and Ti for forming the highest Al component content is placed on one side of the rotating table. -Using an arc ion plating apparatus in which an Al-V alloy and a Ti-V alloy for forming an Al component-free point on the other side as a cathode electrode (evaporation source) are arranged opposite to each other, along the outer periphery of the rotary table of the apparatus A plurality of the substrates are mounted in a ring shape, and in this state, the atmosphere inside the apparatus is changed to a nitrogen atmosphere, the rotating table is rotated, and the substrates themselves are rotated, while the cathode electrodes (evaporation sources) and anodes on both sides are rotated. by generating arc discharge between the electrodes, the surface of the substrate, the hard coating layer made of a composite nitride layer of Al, Ti, and V 1 to 15 m In the overall average layer surface-coated cemented carbide cutting tool comprising depositing a thickness,
The hard coating layer has an Al component highest content point and an Al component non-contained point alternately and repeatedly at predetermined intervals along the layer thickness direction, and the Al component is not contained from the highest Al component content point. Point, having a component concentration distribution structure in which the Al component content continuously changes from the Al component-free point to the Al component highest-containing point,
Furthermore, the highest Al component content point is as follows: Composition formula: [Ti _{1-(X +} _Z ₎ Al _X V _Z ] N (wherein X is 0.40 to 0.65 in terms of atomic ratio, Z : 0.05 to 0.20),
The Al component-free point, the composition _{_{_{formula: (Ti 1- Z V Z)}}} N ( provided that an atomic ratio, Z: shows the 0.05-0.20)
And the interval between the Al component highest content point and the Al component non-contained point adjacent to each other is 0.01 to 0.1 μm,
A surface-coated cemented carbide cutting tool that exhibits excellent chipping resistance in heavy cutting of difficult-to-cut materials characterized by