JP2004314245A

JP2004314245A - Surface coated cemented carbide cutting tool with hard coated layer displaying excellent abrasion resistance in high speed cutting work of hard-to-cut material

Info

Publication number: JP2004314245A
Application number: JP2003112815A
Authority: JP
Inventors: Bunichi Shirase; 文一白瀬
Original assignee: Mitsubishi Materials Corp
Current assignee: Mitsubishi Materials Corp
Priority date: 2003-04-17
Filing date: 2003-04-17
Publication date: 2004-11-11

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface coated cemented carbide made cutting tool a hard coated layer of which displays excellent abrasion resistance in high speed cutting of a hard-to-cut material. <P>SOLUTION: The hard coated layer made of a composite nitride layer of Al, Ti and S is physically evaporated in overall average layer thickness of 1 to 15μm on a surface of a WC group cemented carbide substrate or a carbonitride titanium cermet substrate; S component highest containing points and S component non-contained points alternately and repeatedly exist with specified intervals between them along the layer thickness direction, this cutting tool has an S component density distribution continuous changing structure in which S component content proportional quantity continuously changes from the S component highest containing points to the S component non-contained points and from the S component non-contained points to the S component highest containing points; the S component highest containing points have a specific compositional percentage; and the cutting tool is constituted of the hard coated layer in which the interval between the adjoining S component highest containing point and S component non-contained point is 0.01 to 0.1μm. <P>COPYRIGHT: (C)2005,JPO&NCIPI

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、高強度、さらにすぐれた潤滑性を兼ね備え、したがって特に高熱発生を伴うステンレス鋼やＮｉ基耐熱合金、さらに軟鋼などの難削材の高速切削加工を行なった場合にも、硬質被覆層が長期に亘って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：（Ａｌ_{１−（Ｘ＋Ｙ）}Ｔｉ_ＸＳ_Ｙ）Ｎ（ただし、原子比で、Ｘは０．３５〜０．６０、Ｙ：０．０１〜０．１０を示す）を満足するＡｌとＴｉとＳの複合窒化物［以下、（Ａｌ，Ｔｉ，Ｓ）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（Ａｌ，Ｔｉ，Ｓ）Ｎ層が高温硬さおよび耐熱性、強度、さらに潤滑性を有することから、特に各種の鋼や鋳鉄などの高速切削加工条件で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（例えば特許文献１参照）。
【０００４】
さらに、上記の被覆超硬工具が、例えば図２に概略説明図で示される物理蒸着装置の１種であるアークイオンプレーティング装置に上記の超硬基体を装入し、ヒータで装置内を、例えば５００℃の温度に加熱した状態で、アノード電極と所定組成を有するＡｌ−Ｔｉ−Ｓ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（Ａｌ，Ｔｉ，Ｓ）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】
【特許文献１】
特開２００２−３３１４０６号
【０００６】
【発明が解決しようとする課題】
近年の切削加工装置の高性能化はめざましく、一方で切削加工に対する省力化および省エネ化、さらに低コスト化の要求は強く、これに伴い、被覆超硬工具には被削材の材質に対する汎用性、すなわちできるだけ多くの材質の被削材を切削できる性質を具備することが強く要求される傾向にあるが、上記の従来被覆超硬工具においては、これを通常の鋼や鋳鉄の高速切削加工に用いた場合には問題はないが、特に高熱発生を伴うステンレス鋼やＮｉ基耐熱合金、さらに軟鋼などの難削材の高速切削加工に用いた場合には、高温硬さおよび耐熱性（高温特性）不足が原因で、摩耗進行が著しく促進するようになることから、比較的短時間で使用寿命に至るのが現状である。
【０００７】
【課題を解決するための手段】
そこで、本発明者等は、上述のような観点から、特に高熱発生を伴う難削材の高速切削加工ですぐれた耐摩耗性を発揮する被覆超硬工具を開発すべく、上記の従来被覆超硬工具を構成する硬質被覆層に着目し、研究を行った結果、
（ａ）上記の図２に示されるアークイオンプレーティング装置を用いて形成された従来被覆超硬工具を構成する（Ａｌ，Ｔｉ，Ｓ）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、強度、および潤滑性を有するが、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Ｓ成分最高含有点形成用Ａｌ−Ｔｉ−Ｓ合金、他方側にＳ成分不含有点形成用Ａｌ−Ｔｉ合金をいずれもカソード電極（蒸発源）として対向配置したアークイオンプレーティング装置を用い、この装置の前記回転テーブル上に、これの中心軸から半径方向に所定距離離れた位置に外周部に沿って複数の超硬基体をリング状に装着し、この状態で装置内雰囲気を窒素雰囲気として前記回転テーブルを回転させると共に、蒸着形成される硬質被覆層の層厚均一化を図る目的で超硬基体自体も自転させながら、前記の両側のカソード電極（蒸発源）とアノード電極との間にアーク放電を発生させて、前記超硬基体の表面に（Ａｌ，Ｔｉ，Ｓ）Ｎ層を形成すると、この結果の（Ａｌ，Ｔｉ，Ｓ）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Ａｌ−Ｔｉ−Ｓ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Ｓ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Ａｌ−Ｔｉ合金のカソード電極に最も接近した時点で層中にＳ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Ｓ成分最高含有点とＳ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Ｓ成分最高含有点から前記Ｓ成分不含有点、前記Ｔｉ最低含有点から前記Ｓ成分不含有点へＳ成分含有割合が連続的に変化するＳ成分濃度分布連続変化構造をもつようになること。
【０００８】
（ｂ）上記（ａ）のＳ成分濃度分布連続変化構造の（Ａｌ，Ｔｉ，Ｓ）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Ａｌ−Ｔｉ−Ｓ合金におけるＴｉおよびＳ含有量を上記の従来（Ａｌ，Ｔｉ，Ｓ）Ｎ層形成用Ａｌ−Ｔｉ−Ｓ合金のＴｉおよびＳ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Ａｌ−Ｔｉ合金におけるＴｉ含有量も前記Ａｌ−Ｔｉ−Ｓ合金のＴｉ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Ｓ成分最高含有点が、組成式：（Ａｌ_{１−（Ｘ＋Ｙ）}Ｔｉ_ＸＳ_Ｙ）Ｎ（ただし、原子比で、Ｘは０．３５〜０．６０、Ｙ：０．０１〜０．１０を示す）、
上記Ｓ成分不含有点が、組成式：（Ａｌ_１− _ＸＴｉ_Ｘ）Ｎ（ただし、原子比で、Ｘは０．３５〜０．６０を示す）、
を満足し、かつ隣り合う上記Ｓ成分最高含有点とＳ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Ｓ成分最高含有点部分では、上記の従来（Ａｌ，Ｔｉ，Ｓ）Ｎ層のもつ高温硬さと耐熱性、強度、および潤滑性に相当する高温硬さと耐熱性（高温特性）、強度、さらにすぐれた潤滑性を示し、一方上記Ｓ成分不含有点部分では、実質的にＳ成分を含有しない（Ａｌ，Ｔｉ）Ｎからなるので、相対的にＡｌによる一段の高温硬さと耐熱性の向上、さらに同じくＴｉによる一段の強度向上が図られ、かつこれらＳ成分最高含有点とＳ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潤滑性を保持した状態で、一段とすぐれた高温特性と高強度を具備するようになり、したがって、硬質被覆層がかかる構成の（Ａｌ，Ｔｉ，Ｓ）Ｎ層からなる被覆超硬工具は、特に高熱発生を伴うステンレス鋼やＮｉ基耐熱合金、軟鋼などの難削材の高速切削加工に用いた場合にも、前記硬質被覆層がすぐれた耐摩耗性を発揮するようになること。
以上（ａ）および（ｂ）に示される研究結果を得たのである。
【０００９】
この発明は、上記の研究結果に基づいてなされたものであって、超硬基体の表面に、（Ａｌ，Ｔｉ，Ｓ）Ｎ層からなる硬質被覆層を１〜１５μｍの全体平均層厚で物理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、Ｓ成分最高含有点とＳ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Ｓ成分最高含有点から前記Ｓ成分不含有点、前記Ｓ成分不含有点から前記Ｓ成分最高含有点へＳ成分含有量が連続的に変化するＳ成分濃度分布変化構造を有し、
さらに、上記Ｓ成分最高含有点が、組成式：（Ａｌ_{１−（Ｘ＋Ｙ）}Ｔｉ_ＸＳ_Ｙ）Ｎ（ただし、原子比で、Ｘは０．３５〜０．６０、Ｙ：０．０１〜０．１０を示す）、
上記Ｓ成分不含有点が、組成式：（Ａｌ_１− _ＸＴｉ_Ｘ）Ｎ（ただし、原子比で、Ｘは０．３５〜０．６０を示す）、
を満足し、かつ隣り合う上記Ｓ成分最高含有点とＳ成分不含有点の間隔が、０．０１〜０．１μｍである、
難削材の高速切削加工で硬質被覆層がすぐれた耐摩耗性を発揮する被覆超硬工具に特徴を有するものである。
【００１０】
つぎに、この発明の被覆超硬工具において、これを構成する硬質被覆層の構成を上記の通りに限定した理由を説明する。
（ａ）Ｓ成分最高含有点の組成
Ｓ成分最高含有点の（Ａｌ，Ｔｉ，Ｓ）ＮにおけるＡｌ成分は、高温硬さおよび耐熱性（高温特性）を向上させ、同じくＴｉ成分は強度を向上させ、さらにＳ成分は潤滑性を向上させる作用をもつものであり、したがって、Ｔｉの含有割合を示すＸ値がＡｌとＳの合量に占める割合（原子比）で０．３５未満では、所望の高強度を確保することができず、これがチッピング発生の原因となり、一方そのＸ値が０．６０を越えるとＡｌ成分の含有割合が少なくなり過ぎて高温特性が急激に低下し、摩耗進行が促進するようになり、またＳの含有割合を示すＹ値が同じく０．０１未満では所望のすぐれた潤滑性を確保することができず、一方そのＹ値が０．１０を越えると高温特性および強度に低下傾向が現れるようになることから、Ｘ値を０．３５〜０．６０、Ｙ値を０．０１〜０．１０と定めた。
【００１１】
（ｂ）Ｓ成分不含有点の組成
（Ａｌ，Ｔｉ）ＮからなるＳ成分不含有点によって、上記の通り上記Ｓ成分最高含有点に比して相対的に一段とすぐれた高温特性と高強度を確保し、高熱発生を伴う難削材の高速切削加工にすぐれた耐摩耗性を発揮するようにしたものであり、したがってＸ値が０．３５未満では所望の高強度を確保することができず、一方Ｘ値が０．６０を越えるとすぐれた高温特性の確保は困難になることから、Ｘ値を０．３５〜０．６０と定めた。
【００１２】
（ｃ）Ｓ成分最高含有点とＳ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すぐれた高温特性および強度と潤滑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Ｓ成分最高含有点であれば高温特性および強度不足、Ｓ成分不含有点であれば潤滑性不足が層内に局部的に現れ、これが原因で摩耗進行が促進するようになることから、その間隔を０．０１〜０．１μｍと定めた。
【００１３】
（ｄ）硬質被覆層の平均層厚
その層厚が１μｍ未満では、所望の耐摩耗性を確保することができず、一方その平均層厚が１５μｍを越えると、チッピングが発生し易くなることから、その平均層厚を１〜１５μｍと定めた。
【００１４】
【発明の実施の形態】
つぎに、この発明の被覆超硬工具を実施例により具体的に説明する。
（実施例１）
原料粉末として、いずれも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、Ｃｒ_３Ｃ_２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。
【００１５】
また、原料粉末として、いずれも０．５〜２μｍの平均粒径を有するＴｉＣＮ（重量比でＴｉＣ／ＴｉＮ＝５０／５０）粉末、Ｍｏ_２Ｃ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。
【００１６】
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、これの中心軸から半径方向に所定距離離れた位置に外周部にそって装着し、一方側のカソード電極（蒸発源）として、種々の成分組成をもったＳ成分最高含有点形成用Ａｌ−Ｔｉ−Ｓ合金、他方側のカソード電極（蒸発源）としてＳ成分不含有点形成用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Ｓ成分最高含有点形成用Ａｌ−Ｔｉ−Ｓ合金およびＳ成分不含有点形成用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Ｓ成分最高含有点とＳ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Ｓ成分最高含有点から前記Ｓ成分不含有点、前記Ｓ成分不含有点から前記Ｓ成分最高含有点へＳ成分含有割合が連続的に変化するＳ成分濃度分布連続変化構造を有し、かつ同じく表３，４に示される目標層厚の硬質被覆層を蒸着することにより、本発明被覆超硬工具としての本発明表面被覆超硬合金製スローアウエイチップ（以下、本発明被覆超硬チップと云う）１〜１６をそれぞれ製造した。
【００１７】
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Ａｌ−Ｔｉ−Ｓ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（Ａｌ，Ｔｉ，Ｓ）Ｎ層からなる硬質被覆層を蒸着することにより、従来被覆超硬工具としての従来表面被覆超硬合金製スローアウエイチップ（以下、従来被覆超硬チップと云う）１〜１６をそれぞれ製造した。
【００１８】
つぎに、上記本発明被覆超硬チップ１〜１６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・Ｓ４５Ｃの丸棒、
切削速度：２００ｍ／ｍｉｎ．、
切り込み：２ｍｍ、
送り：０．２ｍｍ／ｒｅｖ．、
切削時間：２０分、
の条件での軟鋼の乾式連続高速切削加工試験、
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：１５０ｍ／ｍｉｎ．、
切り込み：２ｍｍ、
送り：０．２ｍｍ／ｒｅｖ．、
切削時間：１０分、
の条件でのステンレス鋼の乾式断続高速切削加工試験、さらに、
被削材：Ｎｉ基耐熱合金（質量％で、Ｃｒ：１８％、Ｆｅ：１８．５％、Ｍｏ：３％、Ｔｉ：２．４％、Ａｌ：０．５％、Ｎｂ＋Ｔａ：５．１％含有）の丸棒、
切削速度：７０ｍ／ｍｉｎ．、
切り込み：０．２ｍｍ、
送り：０．２ｍｍ／ｒｅｖ．、
切削時間：１０分、
の条件でのＮｉ基耐熱合金の湿式連続高速切削加工試験（水溶性切削油使用）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。
【００１９】
【表１】

【００２０】
【表２】

【００２１】
【表３】

【００２２】
【表４】

【００２３】
【表５】

【００２４】
【表６】

【００２５】
【表７】

【００２６】
（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Ｃｒ_３Ｃ_２粉末、同１．５μｍのＶＣ粉末、同１．０μｍの（Ｔｉ，Ｗ）Ｃ［質量比で、ＴｉＣ／ＷＣ＝５０／５０］粉末、および同１．８μｍのＣｏ粉末を用意し、これら原料粉末をそれぞれ表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を形成し、さらに前記の３種の丸棒焼結体から、研削加工にて、表８に示される組合せで、切刃部の直径×長さがそれぞれ６ｍｍ×１３ｍｍ、１０ｍｍ×２２ｍｍ、および２０ｍｍ×４５ｍｍの寸法、並びにいずれもねじれ角：３０度の４枚刃スクエア形状をもった超硬基体（エンドミル）Ｃ−１〜Ｃ−８をそれぞれ製造した。
【００２７】
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９に示される目標組成のＳ成分最高含有点とＳ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Ｓ成分最高含有点から前記Ｓ成分不含有点、前記Ｓ成分不含有点から前記Ｓ成分最高含有点へＳ成分含有割合が連続的に変化するＳ成分濃度分布連続変化構造を有し、かつ同じく表９に示される目標層厚の硬質被覆層を蒸着することにより、本発明被覆超硬工具としての本発明表面被覆超硬合金製エンドミル（以下、本発明被覆超硬エンドミルと云う）１〜８をそれぞれ製造した。
【００２８】
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１０に示される目標組成および目標層厚を有し、かつ層厚方向に沿って実質的に組成変化のない（Ａｌ，Ｔｉ，Ｓ）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。
【００２９】
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Ｎｉ基耐熱合金（質量％で、Ｃｒ：１８％、Ｆｅ：１８．５％、Ｍｏ：３％、Ｔｉ：２．４％、Ａｌ：０．５％、Ｎｂ＋Ｔａ：５．１％含有）の板材、
切削速度：２５ｍ／ｍｉｎ．、
軸方向切り込み：６ｍｍ、
径方向切り込み：０．３ｍｍ、
テーブル送り：７５ｍｍ／分、
の条件でのＮｉ基耐熱合金の湿式高速側面切削加工試験、本発明被覆超硬エンドミル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：６５ｍ／ｍｉｎ．、
軸方向切り込み：１５ｍｍ、
径方向切り込み：２ｍｍ、
テーブル送り：２９０ｍｍ／分、
の条件でのステンレス鋼の湿式高速側面切削加工試験、本発明被覆超硬エンドミル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・Ｓ４５Ｃの板材、
切削速度：１３０ｍ／ｍｉｎ．、
軸方向切り込み：３００ｍｍ、
径方向切り込み：４ｍｍ、
テーブル送り：１４０ｍｍ／分、
の条件での軟鋼の湿式高速側面切削加工試験をそれぞれ行い、いずれの湿式側面切削加工試験（水溶性切削油使用）でも切刃部の外周刃の逃げ面摩耗幅が使用寿命の目安とされる０．１ｍｍに至るまでの切削長を測定した。この測定結果を表９、１０にそれぞれ示した。
【００３０】
【表８】

【００３１】
【表９】

【００３２】
【表１０】

【００３３】
（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、並びにねじれ角：３度の２枚刃形状をもった超硬基体（ドリル）Ｄ−１〜Ｄ−８をそれぞれ製造した。
【００３４】
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１１に示される目標組成のＳ成分最高含有点とＳ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Ｓ成分最高含有点から前記Ｓ成分不含有点、前記Ｓ成分不含有点から前記Ｓ成分最高含有点へＳ成分含有割合が連続的に変化するＳ成分濃度分布連続変化構造を有し、かつ同じく表１１に示される目標層厚の硬質被覆層を蒸着することにより、本発明被覆超硬工具としての本発明表面被覆超硬合金製ドリル（以下、本発明被覆超硬ドリルと云う）１〜８をそれぞれ製造した。
【００３５】
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１２に示される目標組成および目標層厚を有し、かつ層厚方向に沿って実質的に組成変化のない（Ａｌ，Ｔｉ，Ｓ）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。
【００３６】
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：４０ｍ／ｍｉｎ．、
送り：０．１０ｍｍ／ｒｅｖ、
穴深さ：１２ｍｍ、
の条件でのステンレス鋼の湿式高速穴あけ切削加工試験、本発明被覆超硬ドリル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Ｎｉ基耐熱合金（質量％で、Ｃｒ：１８％、Ｆｅ：１８．５％、Ｍｏ：３％、Ｔｉ：２．４％、Ａｌ：０．５％、Ｎｂ＋Ｔａ：５．１％含有）の板材、
切削速度：４０ｍ／ｍｉｎ．、
送り：０．１２ｍｍ／ｒｅｖ、
穴深さ：２４ｍｍ、
の条件でのＮｉ基耐熱合金の湿式高速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・Ｓ４５Ｃの板材、
切削速度：１７０ｍ／ｍｉｎ．、
送り：０．３５ｍｍ／ｒｅｖ、
穴深さ：５０ｍｍ、
の条件での軟鋼の湿式高速穴あけ切削加工試験、をそれぞれ行い、いずれの湿式高速穴あけ切削加工試験（水溶性切削油使用）でも先端切刃面の逃げ面摩耗幅が０．３ｍｍに至るまでの穴あけ加工数を測定した。この測定結果を表１１、１２にそれぞれ示した。
【００３７】
【表１１】

【００３８】
【表１２】

【００３９】
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、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を構成する硬質被覆層について、厚さ方向に沿ってＡｌ、Ｔｉ、およびＳ成分の含有割合をオージェ分光分析装置を用いて測定したところ、本発明被覆超硬工具では、Ｓ成分最高含有点とＳ成分不含有点とがそれぞれ目標値と実質的に同じ組成および間隔で交互に繰り返し存在し、かつかつ前記Ｓ成分最高含有点から前記Ｓ成分不含有点、前記Ｓ成分不含有点から前記Ｓ成分最高含有点へＳ成分含有割合が連続的に変化するＳ成分濃度分布連続変化構造を有することが確認され、硬質被覆層の平均層厚も目標層厚と実質的に同じ値を示した。一方従来被覆超硬工具の硬質被覆層においては、厚さ方向に沿って組成変化は見られないが、目標値と実質的に同じ組成を示し、また平均層厚も目標層厚と実質的に同じ値を示した。
【００４０】
【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、すぐれた潤滑性を有するＳ成分最高含有点とすぐれた高温硬さと耐熱性を有するＳ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Ｓ成分最高含有点から前記Ｓ成分不含有点、前記Ｓ成分不含有点から前記Ｓ成分最高含有点へＳ成分含有割合が連続的に変化するＳ成分濃度分布連続変化構造を有する本発明被覆超硬工具は、いずれも高熱発生を伴う難削材であるステンレス鋼および軟鋼の高速切削加工に用いた場合にも、硬質被覆層がすぐれた耐摩耗性を発揮するのに対して、硬質被覆層が層厚方向に沿って実質的に組成変化のない（Ａｌ，Ｔｉ，Ｓ）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潤滑性を有するものの、高温硬さと耐熱性が不十分であるために、切削時発生の高熱で摩耗進行が著しく促進されることから、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、通常の鋼や鋳鉄などの高速切削加工は勿論のこと、特にステンレス鋼などの難削材の高速切削加工に場合にも、すぐれた耐摩耗性を長期に亘って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。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides a hard coating layer having excellent high-temperature hardness, heat resistance, high strength, and excellent lubricity. Therefore, high-speed cutting of difficult-to-cut materials such as stainless steel, Ni-based heat-resistant alloys, and mild steel, which particularly generate high heat. The present invention relates to a surface-coated cemented carbide cutting tool (hereinafter referred to as coated cemented carbide tool) in which a hard coating layer exhibits excellent wear resistance over a long period even when cutting is performed.
[0002]
[Prior art]
In general, coated carbide tools are used for throw-away inserts, drilling, etc., which are removably attached to the tip of a cutting tool for turning or planing of various materials such as steel and cast iron. Drills and miniature drills, as well as solid-type end mills used for face milling, grooving, shoulder processing, etc., in which the cutting edge takes an intermittent cutting form, and the solid-type by detachably attaching the throw-away tip There is known a throw-away end mill tool for performing a cutting process in the same manner as the end mill.
[0003]
Further, as a coated cemented 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, these are collectively referred to as a cemented carbide substrate) surface, composition _{formula): (Al 1- (X +} Y) Ti X S Y) N ( provided that an atomic ratio, X is from 0.35 to 0.60, Y: shows the 0.01 to 0.10) Coated hard tool obtained by physical vapor deposition of a hard coating layer composed of a composite nitride of Al, Ti and S [hereinafter, referred to as (Al, Ti, S) N] with an average thickness of 1 to 15 μm. Such coated carbide tools are particularly suitable for various types of steel and steel because the (Al, Ti, S) N layer constituting the hard coating layer has high-temperature hardness, heat resistance, strength, and lubricity. Used for continuous and intermittent cutting under high-speed cutting conditions such as cast iron It is also known to be (for example, see Patent Document 1).
[0004]
Furthermore, the above-mentioned coated carbide tool is charged with the above-mentioned carbide substrate in an arc ion plating apparatus, which is a kind of physical vapor deposition apparatus shown schematically in FIG. 2, for example, and the inside of the apparatus is heated by a heater. For example, an arc discharge is generated between an anode electrode and a cathode electrode (evaporation source) on which an Al-Ti-S 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, a nitrogen gas is introduced as a reaction gas into the apparatus to form a reaction atmosphere of, for example, 2 Pa. On the other hand, the surface of the cemented carbide substrate is applied to the cemented carbide substrate under the condition that a bias voltage of, for example, -100 V is applied. In addition, it is also known that it is manufactured by evaporating a hard coating layer composed of the (Al, Ti, S) N layer.
[0005]
[Patent Document 1]
JP-A-2002-331406 [0006]
[Problems to be solved by the invention]
In recent years, the performance of cutting equipment has been remarkably improved, but on the other hand, there is a strong demand for labor saving, energy saving, and lower cost for cutting work. That is, there is a tendency that it is strongly required to have a property capable of cutting as many materials as possible, but in the above-mentioned conventional coated carbide tool, this is used for high-speed cutting of ordinary steel or cast iron. There is no problem when used, but especially when used for high-speed cutting of difficult-to-cut materials such as stainless steel and Ni-base heat-resistant alloys and mild steel that generate high heat, high-temperature hardness and heat resistance (high-temperature properties) ) Due to the shortage, the progress of wear is remarkably accelerated, so that the service life can be reached in a relatively short time at present.
[0007]
[Means for Solving the Problems]
In view of the above, the present inventors have developed the above-mentioned conventional coated super hard tool to develop a coated super hard tool which exhibits excellent wear resistance particularly in high speed cutting of difficult-to-cut materials with high heat generation. Focusing on the hard coating layer that constitutes the hard tool, as a result of conducting research,
(A) The (Al, Ti, S) N layer constituting the conventional coated carbide tool formed by using the arc ion plating apparatus shown in FIG. 2 is substantially uniform over the entire layer thickness. And therefore has a uniform high-temperature hardness and heat resistance, strength, and lubricity. For example, the arc shown in the schematic plan view in FIG. 1A and the schematic front view in FIG. An ion plating apparatus, that is, a rotary table for mounting a cemented carbide substrate is provided at the center of the apparatus, and an Al-Ti-S alloy for forming the highest S component content point is provided on one side and the S component is not provided on the other side with the rotary table interposed therebetween. An arc ion plating apparatus was used in which all the Al-Ti alloys for forming the content points were opposed to each other as a cathode electrode (evaporation source). The arc ion plating apparatus was placed on the rotary table of the apparatus at a predetermined distance in the radial direction from the center axis thereof. Rank A plurality of super-hard substrates are mounted in a ring shape along the outer peripheral portion, and in this state, the rotating table is rotated while the atmosphere in the apparatus is a nitrogen atmosphere, and the thickness of the hard coating layer formed by vapor deposition is made uniform. For the purpose, an arc discharge is generated between the cathode electrode (evaporation source) and the anode electrode on both sides while rotating the carbide substrate itself, and (Al, Ti, S) N is formed on the surface of the carbide substrate. When the layer is formed, in the resulting (Al, Ti, S) N layer, the cemented carbide substrate arranged in a ring shape on the rotary table has the above-described cathode electrode of the Al-Ti-S alloy on one side ( At the point of closest approach to the (evaporation source), and at the point of closest approach of the cemented carbide substrate to the other Al-Ti alloy cathode electrode on the other side. Non-content point is formed and the rotation With the rotation of the cable, the S component maximum content point and the S component non-content point alternately and repeatedly appear at predetermined intervals in the layer thickness direction along the layer thickness direction, and the S component non-content point from the S component maximum content point, It has an S component concentration distribution continuously changing structure in which the S component content ratio changes continuously from the Ti minimum content point to the S component non-content point.
[0008]
(B) In the (Al, Ti, S) N layer of the S-component concentration distribution continuous change structure of (a), Ti and Al in the Al—Ti—S alloy which is the cathode electrode (evaporation source) on one side of the opposed arrangement. The S content is assumed to correspond to the Ti and S contents of the above-mentioned conventional Al—Ti—S alloy for forming an (Al, Ti, S) N layer, and the Al—Ti—S cathode electrode (evaporation source) on the other side is used. The Ti content in the Ti alloy is the same as the Ti content in the Al-Ti-S alloy, and the rotation speed of the turntable on which the carbide substrate is mounted is controlled.
The S component maximum content point, the composition _{_{formula: (Al 1- (X + Y}} ) Ti X S Y) N ( provided that an atomic ratio, X is from .35 to 0.60, Y: 0.01 to 0.10 ),
The S component-free point, the composition _{_{_{formula: (Al 1- X Ti X)}}} N ( provided that an atomic ratio, X is shows the 0.35 to 0.60),
Is satisfied, and the distance in the thickness direction between the adjacent S component maximum content point and the adjacent S component non-content point is 0.01 to 0.1 μm,
At the highest content point of the S component, the high-temperature hardness and heat resistance (high-temperature properties), strength, and strength corresponding to the high-temperature hardness and heat resistance, strength, and lubricity of the conventional (Al, Ti, S) N layer described above. It shows excellent lubricity, while the above-mentioned S component-free portion is made of (Al, Ti) N substantially containing no S component. In addition, the strength of Ti is further improved, and the interval between the maximum content of S component and the content of non-S component is extremely small. Coated carbide tools made of an (Al, Ti, S) N layer having a hard coating layer having excellent high-temperature properties and high strength, are particularly suitable for stainless steel or Ni-based steel with high heat generation. Heat resistance , Even when used in high speed cutting of difficult-to-cut materials such as mild steel, to become to exert abrasion resistance the hard coating layer has excellent.
The research results shown in (a) and (b) above were obtained.
[0009]
The present invention has been made based on the above research results, and a hard coating layer made of an (Al, Ti, S) N layer is formed on the surface of a super-hard substrate at a total average layer thickness of 1 to 15 μm. In coated carbide tools made by evaporation,
In the hard coating layer, the S component highest content point and the S component non-content point alternately and repeatedly exist at predetermined intervals along the layer thickness direction, and the S component highest content point and the S component free content point Point, having an S component concentration distribution change structure in which the S component content continuously changes from the S component non-content point to the S component maximum content point,
Further, the S component maximum content point, the composition _{_{formula: (Al 1- (X + Y}} ) Ti X S Y) N ( provided that an atomic ratio, X is from 0.35 to .60, Y: .01 to 0 .10),
The S component-free point, the composition _{_{_{formula: (Al 1- X Ti X)}}} N ( provided that an atomic ratio, X is shows the 0.35 to 0.60),
Is satisfied, and the interval between the adjacent S component maximum content point and S component non-content point is 0.01 to 0.1 μm,
The present invention is characterized by a coated carbide tool in which a hard coating layer exhibits excellent wear resistance in high-speed cutting of difficult-to-cut materials.
[0010]
Next, the reason why the configuration of the hard coating layer constituting the coated carbide tool of the present invention is limited as described above will be described.
(A) Composition of the highest content of the S component The Al component in the (S, Al, Ti, S) N having the highest content of the S component improves high-temperature hardness and heat resistance (high-temperature characteristics), and similarly, the Ti component improves strength. In addition, the S component has an effect of improving lubricity. Therefore, if the X value indicating the content ratio of Ti is less than 0.35 in the ratio (atomic ratio) to the total amount of Al and S, it is not desirable. Cannot ensure the high strength of the steel, which causes chipping. On the other hand, when the X value exceeds 0.60, the content ratio of the Al component becomes too small, and the high-temperature characteristics are rapidly reduced, and the wear progresses. When the Y value indicating the content ratio of S is also less than 0.01, desired excellent lubricity cannot be ensured. On the other hand, when the Y value exceeds 0.10, high temperature properties and The strength tends to decrease From becoming, the X value from 0.35 to 0.60, was defined as the Y value 0.01 to 0.10.
[0011]
(B) S-Component-Free Point Composition As described above, the S-component-free point composed of (Al, Ti) N provides higher temperature characteristics and higher strength relatively more excellent than the above-mentioned S-component maximum content point. It ensures high wear resistance in high-speed cutting of difficult-to-cut materials with high heat generation. Therefore, if the X value is less than 0.35, the desired high strength cannot be secured. On the other hand, if the X value exceeds 0.60, it becomes difficult to secure excellent high-temperature characteristics. Therefore, the X value is set to 0.35 to 0.60.
[0012]
(C) Interval between the highest point of S component and the point of non-S component If the interval is less than 0.01 μm, it is difficult to clearly define each point with the above composition, and as a result, it is difficult to form a hard coating layer. If the spacing exceeds 0.1 μm, the disadvantages of each point, that is, if the maximum content of the S component, the high temperature properties and insufficient strength, In the case where the S component is not contained, insufficient lubrication appears locally in the layer, which promotes abrasion. Therefore, the interval is set to 0.01 to 0.1 μm.
[0013]
(D) Average layer thickness of the hard coating layer If the layer thickness is less than 1 μm, the desired wear resistance cannot be secured, while if the average layer thickness exceeds 15 μm, chipping is likely to occur. The average layer thickness was determined to be 1 to 15 μm.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, the coated cemented 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 μm were prepared. The mixture was wet-mixed for 72 hours in a ball mill, dried and pressed into a green compact at a pressure of 100 MPa, and the green compact was heated to 1400 ° C. for 1 hour in a vacuum of 6 Pa. Sintering is performed under the conditions of holding, and after sintering, the cutting edge portion is subjected to honing processing of R: 0.03, and a carbide substrate A1 to A10 made of a WC-based cemented carbide having a chip shape of ISO standard CNMG120408. Was formed.
[0015]
Further, as raw material powder, TiCN (TiC / TiN = 50/50 by weight) powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC powder each having an average particle diameter of 0.5 to 2 μm , Co powder, and Ni powder were prepared, and these raw material powders were blended in the composition shown in Table 2, wet-mixed in a ball mill for 24 hours, dried, and then pressed into a green 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 an ISO standard CNMG120408. Carbide bases B1 to B6 made of TiCN-based cermet having the chip shape described above were formed.
[0016]
Next, each of the above-mentioned super-hard substrates A1 to A10 and B1 to B6 was ultrasonically cleaned in acetone, and dried, and placed on a rotary table in an arc ion plating apparatus shown in FIG. Attached along the outer periphery at a position radially away from the central axis at a predetermined distance, and as one cathode electrode (evaporation source), Al-Ti-S for forming the highest S component content point having various component compositions. An alloy and an Al-Ti alloy for forming an S-component-free point as a cathode electrode (evaporation source) on the other side are disposed to face each other with the rotary table interposed therebetween, and a metal Ti for bombarding is also mounted. After heating the inside of the apparatus to 500 ° C. with a heater while maintaining a vacuum of 0.5 Pa or less, a DC bias voltage of −1000 V is applied to the carbide substrate rotating while rotating on the rotary table. A current of 100 A is applied between the metal Ti of the cathode electrode and the anode electrode to generate an arc discharge, thereby cleaning the surface of the cemented carbide substrate with Ti bombardment, and then introducing nitrogen gas as a reaction gas into the apparatus. To a reaction atmosphere of 2 Pa, and a DC bias voltage of -100 V is applied to the superhard substrate rotating while rotating on the rotary table, and each of the cathode electrodes (the Al-Ti for forming the highest content point of the S component) is applied. A current of 100 A is caused to flow between the anode and the anode electrode to generate an arc discharge between the S-alloy and the Al-Ti alloy for forming an S-component-free point, thereby causing an arc discharge to occur along the layer thickness direction. The S component maximum content points and the S component non-content points of the target compositions shown in Tables 3 and 4 are alternately present at the target intervals shown in Tables 3 and 4 alternately. From the content point to the S component non-content point, from the S component non-content point to the S component maximum content point, the S component content ratio has an S component concentration distribution continuously changing structure, and Table 3, By depositing a hard coating layer having a target layer thickness shown in No. 4, a throw-away tip made of a surface-coated cemented carbide of the present invention (hereinafter referred to as the coated cemented carbide tip of the present invention) 1 as a coated carbide tool of the present invention. 16 were each manufactured.
[0017]
For the purpose of comparison, these super-hard substrates A1 to A10 and B1 to B6 were ultrasonically cleaned in acetone, dried, and charged into a usual arc ion plating apparatus shown in FIG. An Al—Ti—S alloy having various component compositions is mounted as a cathode electrode (evaporation source), and a metal Ti for bombarding is also mounted. First, the inside of the apparatus is evacuated to a vacuum of 0.5 Pa or less. After the inside of the apparatus was heated to 500 ° C. with a heater while holding, a DC bias voltage of −1000 V was applied to the superhard substrate, and a current of 100 A was passed between the metal Ti of the cathode electrode and the anode electrode. An arc discharge is generated, and the surface of the cemented carbide substrate is cleaned by Ti bombarding. Then, nitrogen gas is introduced into the apparatus as a reaction gas to make a reaction atmosphere of 2 Pa, Is reduced to -100 V to generate an arc discharge between the cathode electrode and the anode electrode, and the surface of each of the cemented carbide substrates A1 to A10 and B1 to B6 is applied to Tables 5 and 6 By depositing a hard coating layer composed of an (Al, Ti, S) N layer having a target composition and a target layer thickness shown in FIG. Conventional surface-coated cemented carbide throwaway tips (hereinafter referred to as conventionally coated cemented carbide tips) 1 to 16 as hard tools were manufactured, respectively.
[0018]
Next, with respect to the above-mentioned coated carbide tips 1 to 16 of the present invention and conventional coated carbide tips 1 to 16, in a state where they were screwed to the tip of a tool steel tool with a fixing jig,
Work material: JIS S45C round bar,
Cutting speed: 200 m / min. ,
Cut: 2mm,
Feed: 0.2 mm / rev. ,
Cutting time: 20 minutes,
Dry continuous high-speed cutting test of mild steel under the conditions of
Work material: Round bar with four vertical grooves at equal intervals in the length direction of JIS / SUS304,
Cutting speed: 150 m / min. ,
Cut: 2mm,
Feed: 0.2 mm / rev. ,
Cutting time: 10 minutes,
Intermittent high-speed cutting test of stainless steel under the following conditions,
Work material: Ni-base heat-resistant alloy (in mass%, Cr: 18%, Fe: 18.5%, Mo: 3%, Ti: 2.4%, Al: 0.5%, Nb + Ta: 5.1% Containing) round bar,
Cutting speed: 70 m / min. ,
Cut: 0.2mm
Feed: 0.2 mm / rev. ,
Cutting time: 10 minutes,
Under the above conditions, a wet continuous high-speed cutting test (using a water-soluble cutting oil) was performed on the Ni-base heat-resistant alloy, and the flank wear width of the cutting edge was measured in each cutting test. Table 7 shows the measurement results.
[0019]
[Table 1]

[0020]
[Table 2]

[0021]
[Table 3]

[0022]
[Table 4]

[0023]
[Table 5]

[0024]
[Table 6]

[0025]
[Table 7]

[0026]
(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, and ZrC of 1.2 μm Powder, 2.3 μm Cr ₃ C ₂ powder, 1.5 μm VC powder, 1.0 μm (Ti, W) C [TiC / WC = 50/50 by mass ratio] powder, and 1 μm 0.8 μm Co powder was prepared, and each of these raw material powders was blended into the blending composition shown in Table 8, further added with wax, and ball-mixed in acetone for 24 hours, dried under reduced pressure, and then dried at a pressure of 100 MPa to a predetermined shape. And press-molding these compacts to a predetermined temperature in the range of 1370 to 1470 ° C. at a rate of 7 ° C./min in a vacuum atmosphere of 6 Pa. After holding at temperature for 1 hour, sintering under furnace cooling Then, three types of round bar sintered bodies for forming a cemented carbide substrate having a diameter of 8 mm, 13 mm, and 26 mm were formed. Carbide substrate having dimensions of 6 mm × 13 mm, 10 mm × 22 mm, and 20 mm × 45 mm, respectively, and a four-flute square shape with a torsion angle of 30 ° (diameter × length of the cutting edge portion is 30 mm). End mills) C-1 to C-8 were produced respectively.
[0027]
Then, these super-hard substrates (end mills) C-1 to C-8 were ultrasonically cleaned in acetone, dried, and charged into an arc ion plating apparatus also shown in FIG. Under the same conditions as in Example 1, the S component maximum content points and the S component non-content points of the target composition shown in Table 9 alternately exist at the target intervals shown in Table 9 alternately along the layer thickness direction, And the S component concentration distribution continuously changing structure in which the S component content ratio continuously changes from the S component maximum content point to the S component non-content point, from the S component non-content point to the S component maximum content point, Further, by depositing a hard coating layer having the target layer thickness also shown in Table 9, an end mill made of the surface-coated cemented carbide of the present invention as a coated carbide tool of the present invention (hereinafter referred to as the coated carbide end mill of the present invention) 1 To 8 were each manufactured.
[0028]
For the purpose of comparison, the above-mentioned ultra-hard substrates (end mills) C-1 to C-8 were ultrasonically cleaned in acetone and dried, and then a normal arc ion plating apparatus also shown in FIG. Under the same conditions as in Example 1 above, having the target composition and target layer thickness shown in Table 10, and having substantially no composition change along the layer thickness direction (Al, Ti, S 3) End mills made of conventional surface-coated cemented carbide (hereinafter referred to as conventional coated carbide end mills) 1 to 8 as conventional coated cemented carbide tools were produced by depositing a hard coating layer composed of an N layer.
[0029]
Next, among the coated carbide end mills 1 to 8 of the present invention and the conventional coated carbide end mills 1 to 8, of the coated carbide end mills 1 to 3 and the coated carbide end mills 1 to 3 of the present invention,
Work material: Ni-based heat-resistant alloy with plane dimensions: 100 mm x 250 mm, thickness: 50 mm (Cr: 18%, Fe: 18.5%, Mo: 3%, Ti: 2.4%, Al: : 0.5%, Nb + Ta: 5.1% content)
Cutting speed: 25 m / min. ,
Axial cut: 6 mm
Radial cut: 0.3mm,
Table feed: 75 mm / min,
For the wet high-speed side cutting test of the Ni-base heat-resistant alloy under the following conditions, the coated carbide end mills 4 to 6 of the present invention and the conventionally coated carbide end mills 4 to 6,
Work material: Plane dimensions: 100 mm x 250 mm, thickness: 50 mm, JIS SUS304 plate,
Cutting speed: 65 m / min. ,
Axial cut: 15 mm
Radial cut: 2mm,
Table feed: 290 mm / min,
For the wet-type high-speed side 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 dimensions: 100 mm x 250 mm, thickness: 50 mm JIS S45C plate,
Cutting speed: 130 m / min. ,
Axial cut: 300 mm,
Radial cut: 4mm,
Table feed: 140 mm / min,
Wet high-speed side surface cutting test of mild steel under the conditions of each, and in any wet side surface cutting test (using water-soluble cutting oil), the flank wear width of the outer peripheral edge of the cutting edge is used as a guide for service life The cutting length up to 0.1 mm was measured. The measurement results are shown in Tables 9 and 10, respectively.
[0030]
[Table 8]

[0031]
[Table 9]

[0032]
[Table 10]

[0033]
(Example 3)
The diameters produced in Example 2 were 8 mm (for forming the super-hard substrates C-1 to C-3), 13 mm (for forming the super-hard substrates C-4 to C-6), and 26 mm (for the super-hard substrates C-). 7, for forming C-8), the diameter x length of the groove forming portion was 4 mm x 13 mm (by grinding) from the three types of round rod sintered bodies by grinding. Dimensions of carbide substrate D-1 to D-3), 8 mm × 22 mm (carbide substrate D-4 to D-6), and 16 mm × 45 mm (carbide substrate D-7, D-8), and torsion angle : Carbide bases (drills) D-1 to D-8 each having a three-degree two-blade shape were manufactured.
[0034]
Next, the cutting blades of the super hard substrates (drills) D-1 to D-8 are honed, ultrasonically cleaned in acetone, and dried, and then the arc ion plating apparatus shown in FIG. Under the same conditions as in Example 1 above, the highest S component content point and the lowest S component content point of the target composition shown in Table 11 are alternately shown in Table 11 along the layer thickness direction. An S component concentration distribution which is present repeatedly at a target interval and in which the S component content ratio continuously changes from the S component maximum content point to the S component non-content point, and from the S component non-content point to the S component maximum content point. By depositing a hard coating layer having a continuously variable structure and a target layer thickness also shown in Table 11, a drill made of the surface coated cemented carbide of the present invention as a coated carbide tool of the present invention (hereinafter referred to as coating of the present invention) Carbide drill) 1-8 Each was produced.
[0035]
Also, 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, and are also shown in FIG. It was charged in a normal arc ion plating apparatus, and had the target composition and the target layer thickness shown in Table 12 under the same conditions as in Example 1 above, and the composition change substantially along the layer thickness direction. By depositing a hard coating layer consisting of a non-aluminum (Al, Ti, S) N layer, a drill made of a conventional surface-coated cemented carbide as a conventionally coated carbide tool (hereinafter referred to as a conventional coated carbide drill) 1-8 Was manufactured respectively.
[0036]
Next, of the coated carbide drills 1 to 8 of the present invention and the coated carbide drills 1 to 8 of the related art, the coated carbide drills 1 to 3 of the present invention and the covered carbide drills 1 to 3 of the present invention are:
Work material: Plane dimensions: 100 mm x 250 mm, thickness: 50 mm, JIS SUS304 plate,
Cutting speed: 40 m / min. ,
Feed: 0.10 mm / rev,
Hole depth: 12mm,
For the wet-type high-speed drilling and cutting test of stainless steel under the following conditions, the coated carbide drills 4 to 6 of the present invention and the conventionally coated carbide drills 4 to 6,
Work material: Ni-based heat-resistant alloy with plane dimensions: 100 mm x 250 mm, thickness: 50 mm (Cr: 18%, Fe: 18.5%, Mo: 3%, Ti: 2.4%, Al: : 0.5%, Nb + Ta: 5.1% content)
Cutting speed: 40 m / min. ,
Feed: 0.12 mm / rev,
Hole depth: 24mm,
For the wet-type high-speed drilling test of the Ni-base heat-resistant alloy under the following conditions, the coated carbide drills 7 and 8 of the present invention and the conventionally coated carbide drills 7 and 8
Work material: Plane dimensions: 100 mm x 250 mm, thickness: 50 mm JIS S45C plate,
Cutting speed: 170 m / min. ,
Feed: 0.35 mm / rev,
Hole depth: 50mm,
Welding high-speed drilling cutting test of mild steel under the conditions described above, and in any wet high-speed drilling cutting test (using water-soluble cutting oil), the flank wear width of the tip cutting edge surface reaches 0.3 mm. The number of drilling operations was measured. The measurement results are shown in Tables 11 and 12, respectively.
[0037]
[Table 11]

[0038]
[Table 12]

[0039]
The coated carbide tips 1-16, coated carbide end mills 1-8, coated drills 1-8, and coated carbide tools of the present invention as the coated carbide tools of the present invention obtained as a result. The hard coating layers constituting the conventional coated carbide tips 1 to 16, the conventional coated carbide end mills 1 to 8 and the conventional coated carbide drills 1 to 8 as Al, Ti, and S components along the thickness direction Was measured using an Auger spectroscopy analyzer, the coated cemented carbide tool of the present invention, the S component maximum content point and the S component non-content point alternately at substantially the same composition and interval as the target value respectively An S component concentration distribution continuously changing structure in which the S component content ratio is repeatedly present and the S component content ratio continuously changes from the S component maximum content point to the S component non-content point, and from the S component non-content point to the S component maximum content point. With Rukoto is confirmed, the average layer thickness of the hard layer showed a target layer thickness substantially the same value. On the other hand, in the hard coating layer of the conventionally coated cemented carbide tool, no composition change is observed along the thickness direction, but the composition shows substantially the same composition as the target value, and the average layer thickness is substantially the same as the target layer thickness. Showed the same value.
[0040]
【The invention's effect】
From the results shown in Tables 3 to 12, the hard coating layer was alternately determined in the layer thickness direction with an S component maximum content point having excellent lubricity and an S component non-content point having excellent high-temperature hardness and heat resistance. An S component concentration which is repeatedly present at intervals and at which the S component content continuously changes from the S component maximum content point to the S component non-content point and from the S component non-content point to the S component maximum content point The coated carbide tool of the present invention having a continuously changing structure has excellent wear resistance even when used for high-speed cutting of stainless steel and mild steel, which are both difficult-to-cut materials with high heat generation. On the other hand, in the conventional coated cemented carbide tool in which the hard coating layer is composed of the (Al, Ti, S) N layer having substantially no composition change along the layer thickness direction, the hard coating layer is excellent. High lubricity, high temperature hardness and resistance For sex is insufficient, since the wear proceeds in high heat cutting during occurrence is promoted considerably, it is clear that lead to a relatively short time service life.
As described above, the coated carbide tool of the present invention has excellent wear resistance, not only for high-speed cutting of ordinary steel and cast iron, but also for particularly high-speed cutting of difficult-to-cut materials such as stainless steel. Therefore, it is possible to satisfactorily cope with labor saving and energy saving of the cutting process, and further lowering the cost, since the property is exhibited over a long period of time.
[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 conventional arc ion plating apparatus used for forming a hard coating layer constituting a conventional coated carbide tool.

Claims

A hard coating layer composed of a composite nitride layer of Al, Ti, and S (sulfur) is physically vapor-deposited on the surface of a tungsten carbide-based cemented carbide substrate or a titanium carbonitride-based cermet substrate with a total average layer thickness of 1 to 15 μm. Surface coated cemented carbide cutting tools
In the hard coating layer, the S component highest content point and the S component non-content point alternately and repeatedly exist at predetermined intervals along the layer thickness direction, and the S component highest content point and the S component free content point Point, having an S component concentration distribution continuous change structure in which the S component content ratio continuously changes from the S component non-containing point to the S component highest content point,
Further, the S component maximum content point, the composition _{_{formula: (Al 1- (X + Y}} ) Ti X S Y) N ( provided that an atomic ratio, X is from 0.35 to .60, Y: .01 to 0 shows a .10), the S component-free point, the composition _{_{_{formula: (Al 1- X Ti X)}}} N ( provided that an atomic ratio, X is shows the 0.35 to 0.60),
Satisfies, and the interval between adjacent S component maximum content point and S component non-content point is 0.01 to 0.1 μm,
A surface-coated cemented carbide cutting tool with a hard coating layer that exhibits excellent wear resistance during high-speed cutting of difficult-to-cut materials.