JP3928459B2

JP3928459B2 - Cutting tool made of surface-coated cemented carbide that provides excellent wear resistance with a hard coating layer in high-speed cutting of difficult-to-cut materials

Info

Publication number: JP3928459B2
Application number: JP2002098394A
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: 2002-04-01
Filing date: 2002-04-01
Publication date: 2007-06-13
Anticipated expiration: 2022-04-01
Also published as: JP2003291004A

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熱伝導性を有し、かつ高温硬さと耐熱性にもすぐれ、したがって特に高熱発生を伴うステンレス鋼などの難削材の高速切削加工を行なった場合にも、硬質被覆層がすぐれた放熱性を発揮し、これによって切刃部の熱塑性変形が抑制されるようになり、この結果熱塑性変形が原因の偏摩耗が防止されることから、長期に亘ってすぐれた耐摩耗性を発揮するようにな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_XＳｉ_Y）Ｎ（ただし、原子比で、Ｘは０．３０〜０．４５、Ｙ：０．０５〜０．１５を示す）を満足するＡｌとＴｉとＳｉの複合窒化物［以下、（Ａｌ，Ｔｉ，Ｓｉ）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，Ｓｉ）Ｎ層がすぐれた高温特性（高温硬さおよび耐熱性）を有することから、各種の鋼や鋳鉄などの連続切削や断続切削加工に用いられることも知られている。
【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−Ｓｉ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，Ｓｉ）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、切削加工は高速化の傾向にあるが、上記の従来被覆超硬工具においては、これを通常の切削加工条件で用いた場合には問題はないが、特に高熱発生を伴うステンレス鋼などの難削材の高速切削加工に用いた場合には、切刃部に熱塑性変形が発生し、これが原因で偏摩耗を起すことから、摩耗進行が著しく促進されるようになり、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、特に難削材の高速切削加工で発生する高熱によっても切刃部に熱塑性変形の発生がない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，Ｓｉ）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Ｔｉ成分最高含有点形成用Ａｌ−Ｔｉ−Ｓｉ合金、他方側にＴｉ成分不含有点形成用Ａｌ−Ｓｉ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（Ａｌ，Ｔｉ，Ｓｉ）Ｎ層を形成すると、この結果の（Ａｌ，Ｔｉ，Ｓｉ）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−Ｓｉ合金のカソード電極（蒸発源）に最も接近した時点で層中にＴｉ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−Ｓｉ合金のカソード電極に最も接近した時点で層中にＴｉ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Ｔｉ成分最高含有点とＴｉ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Ｔｉ成分最高含有点から前記Ｔｉ成分不含有点、前記Ｔｉ最低含有点から前記Ｔｉ成分不含有点へＴｉ成分含有量が連続的に変化する成分濃度分布構造を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（Ａｌ，Ｔｉ，Ｓｉ）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−Ｓｉ合金におけるＴｉおよびＳｉ含有量を上記の従来（Ａｌ，Ｔｉ，Ｓｉ）Ｎ層形成用Ａｌ−Ｔｉ−Ｓｉ合金のＴｉおよびＳｉ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−Ｓｉ合金におけるＳｉ含有量を前記Ａｌ−Ｔｉ−Ｓｉ合金のＳｉ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Ｔｉ成分最高含有点が、組成式：（Ａｌ_1-(X+Y)Ｔｉ_XＳｉ_Y）Ｎ（ただし、原子比で、Ｘは０．３０〜０．４５、Ｙ：０．０５〜０．１５を示す）、
上記Ｔｉ成分不含有点が、組成式：（Ａｌ_1-YＳｉ_Y）Ｎ（ただし、原子比で、Ｙ：０．０５〜０．１５を示す）、
を満足し、かつ隣り合う上記Ｔｉ成分最高含有点とＴｉ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Ｔｉ成分最高含有点部分では、上記の従来（Ａｌ，Ｔｉ，Ｓｉ）Ｎ層のもつ高温硬さと耐熱性に相当するすぐれた高温硬さと耐熱性（高温特性）を示し、一方上記Ｔｉ成分不含有点部分では、実質的にＴｉを含有しない（Ａｌ，Ｓｉ）Ｎ、すなわち著しく熱伝導性にすぐれたＡｌＮに耐熱性向上の目的でＳｉを含有させたものからなる（Ａｌ，Ｓｉ）Ｎで構成されるようになるので、きわめて高い放熱性を示すようになり、かつこれらＴｉ成分最高含有点とＴｉ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を保持した状態で一段とすぐれた放熱性を発揮するようになり、したがって、硬質被覆層がかかる構成の（Ａｌ，Ｔｉ，Ｓｉ）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放熱性を発揮し、切削時に発生した高熱を除去することから、切刃部における熱塑性変形の発生が防止され、切刃部の摩耗状況は常に正常摩耗が保持されることになり、偏摩耗による摩耗促進が抑制されるようになること。
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Ｔｉ成分最高含有点形成用Ａｌ−Ｔｉ−Ｓｉ合金、他方側にＴｉ成分不含有点形成用Ａｌ−Ｓｉ合金をカソード電極（蒸発源）として対向配置したアークイオンプレーティング装置を用い、前記回転テーブルの外周部に沿って複数の超硬基体をリング状に装着し、この状態で装置内雰囲気を窒素雰囲気として前記回転テーブルを回転させると共に、超硬基体自体も自転させながら、前記の両側のカソード電極（蒸発源）とアノード電極との間にアーク放電を発生させて、超硬基体の表面に、（Ａｌ，Ｔｉ，Ｓｉ）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、Ｔｉ成分最高含有点とＴｉ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Ｔｉ成分最高含有点から前記Ｔｉ成分不含有点、前記Ｔｉ成分不含有点から前記Ｔｉ成分最高含有点へＴｉ成分含有量が連続的に変化する成分濃度分布構造を有し、さらに、
上記Ｔｉ成分最高含有点が、組成式：（Ａｌ_1-(X+Y)Ｔｉ_XＳｉ_Y）Ｎ（ただし、原子比で、Ｘは０．３０〜０．４５、Ｙ：０．０５〜０．１５を示す）、
上記Ｔｉ成分不含有点が、組成式：（Ａｌ_1-YＳｉ_Y）Ｎ（ただし、原子比で、Ｙ：０．０５〜０．１５を示す）、
を満足し、かつ隣り合う上記Ｔｉ成分最高含有点とＴｉ成分不含有点の間隔が、０．０１〜０．１μmである、
難削材の高速切削で硬質被覆層がすぐれた耐摩耗性を発揮する被覆超硬工具に特徴を有するものである。
【０００９】
つぎに、この発明の被覆超硬工具において、これを構成する硬質被覆層の構成を上記の通りに限定した理由を説明する。
（ａ）Ｔｉ成分最高含有点の組成
Ｔｉ成分最高含有点の（Ａｌ，Ｔｉ，Ｓｉ）ＮにおけるＴｉ成分は、ＡｌおよびＳｉとの共存において高温硬さおよび耐熱性（高温特性）を向上させ、同じくＳｉ成分はさらに一段と耐熱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Ｓｉの合量に占める割合（原子比）で０．３０未満でも、またＳｉの含有割合を示すＹ値が同じく０．０５未満でも前記高温特性に所望の向上効果が得られず、一方Ｘ値が同０．４５を越えても、またＹ値が同０．１５を越えても、前記高温特性に低下傾向が現れるようになることから、Ｘ値を０．３０〜０．４５、Ｙ値を０．０５〜０．１５と定めた。
【００１０】
（ｂ）Ｔｉ成分不含有点の組成
Ｔｉ成分不含有点の（Ａｌ，Ｓｉ）ＮにおけるＳｉ成分は、上記の通りきわめてすぐれた熱伝導性を有するＡｌＮの耐熱性を向上させ、高熱発生を伴う難削材の高速切削に適応させる目的で含有するものであり、したがってＹ値が０．０５未満では所望の耐熱性向上効果が得られず、一方Ｙ値が０．１５を越えるとＴｉ成分不含有点の熱伝導性に低下傾向が現れるようになり、所望のすぐれた放熱効果を発揮することが困難になることから、Ｙ値を０．０５〜０．１５と定めた。
【００１１】
（ｃ）Ｔｉ成分最高含有点とＴｉ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と熱伝導性を確保することができなくなり、またその間隔が０．１μmを越えるとそれぞれの点がもつ欠点、すなわちＴｉ成分最高含有点であれば熱伝導性不足、Ｔｉ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、これが原因で切刃部に熱塑性変形が発生し易くなったり、摩耗進行が促進されるようになることから、その間隔を０．０１〜０．１μmと定めた。
【００１２】
（ｄ）硬質被覆層の全体平均層厚
その層厚が１μｍ未満では、所望の耐摩耗性を確保することができず、一方その平均層厚が１５μｍを越えると、チッピングが発生し易くなることから、その平均層厚を１〜１５μｍと定めた。
【００１３】
【発明の実施の形態】
つぎに、この発明の被覆超硬工具を実施例により具体的に説明する。
（実施例１）
原料粉末として、いずれも１〜３μｍの平均粒径を有するＷＣ粉末、ＴｉＣ粉末、ＶＣ粉末、ＴａＣ粉末、ＮｂＣ粉末、Ｃｒ₃Ｃ₂粉末、およびＣｏ粉末を用意し、これら原料粉末を、表１に示される配合組成に配合し、ボールミルで７２時間湿式混合し、乾燥した後、１００ＭＰａの圧力で圧粉体にプレス成形し、この圧粉体を６Ｐａの真空中、温度：１４００℃に１時間保持の条件で焼結し、焼結後、切刃部分にＲ：０．０３のホーニング加工を施してＩＳＯ規格・ＣＮＭＧ１２０４０８のチップ形状をもったＷＣ基超硬合金製の超硬基体Ａ１〜Ａ１０を形成した。
【００１４】
また、原料粉末として、いずれも０．５〜２μｍの平均粒径を有するＴｉＣＮ（重量比でＴｉＣ／ＴｉＮ＝５０／５０）粉末、Ｍｏ₂Ｃ粉末、ＺｒＣ粉末、ＮｂＣ粉末、ＴａＣ粉末、ＷＣ粉末、Ｃｏ粉末、およびＮｉ粉末を用意し、これら原料粉末を、表２に示される配合組成に配合し、ボールミルで２４時間湿式混合し、乾燥した後、１００ＭＰａの圧力で圧粉体にプレス成形し、この圧粉体を２ｋＰａの窒素雰囲気中、温度：１５００℃に１時間保持の条件で焼結し、焼結後、切刃部分にＲ：０．０３のホーニング加工を施してＩＳＯ規格・ＣＮＭＧ１２０４０８のチップ形状をもったＴｉＣＮ系サーメット製の超硬基体Ｂ１〜Ｂ６を形成した。
【００１５】
ついで、上記の超硬基体Ａ１〜Ａ１０およびＢ１〜Ｂ６のそれぞれを、アセトン中で超音波洗浄し、乾燥した状態で、図１に示されるアークイオンプレーティング装置内の回転テーブル上に外周部にそって装着し、一方側のカソード電極（蒸発源）として、種々の成分組成をもったＴｉ成分最高含有点形成用Ａｌ−Ｔｉ−Ｓｉ合金、他方側のカソード電極（蒸発源）としてＴｉ成分不含有点形成用Ａｌ−Ｓｉ合金を前記回転テーブルを挟んで対向配置し、またボンバート洗浄用金属Ｔｉも装着し、まず、装置内を排気して０．５Ｐａ以下の真空に保持しながら、ヒーターで装置内を５００℃に加熱した後、前記回転テーブル上で自転しながら回転する超硬基体に−１０００Ｖの直流バイアス電圧を印加し、カソード電極の前記金属Ｔｉとアノード電極との間に１００Ａの電流を流してアーク放電を発生させ、もって超硬基体表面をＴｉボンバート洗浄し、ついで装置内に反応ガスとして窒素ガスを導入して２Ｐａの反応雰囲気とすると共に、前記回転テーブル上で自転しながら回転する超硬基体に−１００Ｖの直流バイアス電圧を印加し、それぞれのカソード電極(前記Ｔｉ成分最高含有点形成用Ａｌ−Ｔｉ−Ｓｉ合金およびＴｉ成分不含有点形成用Ａｌ−Ｓｉ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Ｔｉ成分最高含有点とＴｉ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Ｔｉ成分最高含有点から前記Ｔｉ成分不含有点、前記Ｔｉ成分不含有点から前記Ｔｉ成分最高含有点へＴｉ成分含有量が連続的に変化する成分濃度分布構造を有し、かつ同じく表３，４に示される目標全体層厚の硬質被覆層を蒸着することにより、図３（ａ）に概略斜視図で、同（ｂ）に概略縦断面図で示される形状を有する本発明被覆超硬工具としての本発明表面被覆超硬合金製スローアウエイチップ（以下、本発明被覆超硬チップと云う）１〜１６をそれぞれ製造した。
【００１６】
また、比較の目的で、これら超硬基体Ａ１〜Ａ１０およびＢ１〜Ｂ６を、アセトン中で超音波洗浄し、乾燥した状態で、それぞれ図２に示される通常のアークイオンプレーティング装置に装入し、カソード電極（蒸発源）として種々の成分組成をもったＡｌ−Ｔｉ−Ｓｉ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，Ｓｉ）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：２５０ｍ／ｍｉｎ．、
切り込み：１ｍｍ、
送り：０．２５ｍｍ／ｒｅｖ．、
切削時間：１０分、
の条件でのステンレス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：２００ｍ／ｍｉｎ．、
切り込み：１．５ｍｍ、
送り：０．２ｍｍ／ｒｅｖ．、
切削時間：４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：ＪＩＳ・ＳＣＭｎＨ２の丸棒、
切削速度：１５０ｍ／ｍｉｎ．、
切り込み：１ｍｍ、
送り：０．２ｍｍ／ｒｅｖ．、
切削時間：１０分、
の条件での高マンガン鋼の乾式連続高速切削加工試験を行い、いずれの切削加工試験でも切刃の逃げ面摩耗幅を測定した。この測定結果を表７に示した。
【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。
【００２６】
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Ｔｉ成分最高含有点とＴｉ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Ｔｉ成分最高含有点から前記Ｔｉ成分不含有点、前記Ｔｉ成分不含有点から前記Ｔｉ成分最高含有点へＴｉ成分含有量が連続的に変化する成分濃度分布構造を有し、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，Ｓｉ）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・ＳＣＭｎＨ２の板材、
切削速度：８０ｍ／ｍｉｎ．、
溝深さ（切り込み）：１ｍｍ、
テーブル送り：２４０ｍｍ／分、
の条件での高マンガン鋼の乾式高速溝切削加工試験、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：１００ｍ／ｍｉｎ．、
溝深さ（切り込み）：２．５ｍｍ、
テーブル送り：２４０ｍｍ／分、
の条件でのステンレス鋼の乾式高速溝切削加工試験、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：１００ｍ／ｍｉｎ．、
溝深さ（切り込み）：５．０ｍｍ、
テーブル送り：１２０ｍｍ／分、
の条件でのステンレス鋼の乾式高速溝切削加工試験をそれぞれ行い、いずれの溝切削加工試験でも切刃部の外周刃の逃げ面摩耗幅が使用寿命の目安とされる０．１ｍｍに至るまでの切削溝長を測定した。この測定結果を表９、１０にそれぞれ示した。
【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（超硬基体Ｃ−１〜Ｃ−３形成用）、１３ｍｍ（超硬基体Ｃ−４〜Ｃ−６形成用）、および２６ｍｍ（超硬基体Ｃ−７、Ｃ−８形成用）の３種の丸棒焼結体を用い、この３種の丸棒焼結体から、研削加工にて、溝形成部の直径×長さがそれぞれ４ｍｍ×１３ｍｍ（超硬基体Ｄ−１〜Ｄ−３）、８ｍｍ×２２ｍｍ（超硬基体Ｄ−４〜Ｄ−６）、および１６ｍｍ×４５ｍｍ（超硬基体Ｄ−７、Ｄ−８）の寸法をもった超硬基体（ドリル）Ｄ−１〜Ｄ−８をそれぞれ製造した。
【００３３】
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Ｔｉ成分最高含有点とＴｉ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Ｔｉ成分最高含有点から前記Ｔｉ成分不含有点、前記Ｔｉ成分不含有点から前記Ｔｉ成分最高含有点へＴｉ成分含有量が連続的に変化する成分濃度分布構造を有し、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，Ｓｉ）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：６０ｍ／ｍｉｎ．、
送り：０．１ｍｍ／ｒｅｖ、
穴深さ：４ｍｍ
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ＪＩＳ・ＳＣＭｎＨ２の板材、
切削速度：５５ｍ／ｍｉｎ．、
送り：０．１ｍｍ／ｒｅｖ、
穴深さ：８ｍｍ
の条件での高マンガン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：６０ｍ／ｍｉｎ．、
送り：０．１ｍｍ／ｒｅｖ、
穴深さ：１６ｍｍ
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、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。
【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Ｔｉ成分最高含有点とＴｉ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Ｔｉ成分最高含有点とＴｉ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を有するＴｉ成分最高含有点とすぐれた放熱性（熱伝導性）を有するＴｉ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Ｔｉ成分最高含有点から前記Ｔｉ成分不含有点、前記Ｔｉ成分不含有点から前記Ｔｉ成分最高含有点へＴｉ成分含有量が連続的に変化する成分濃度分布構造を有する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高マンガン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放熱性を発揮し、切刃部が切削時発生の高熱で過熱されることがなくなることから、熱塑性変形の発生も抑制され、切刃部は正常摩耗形態を常に示すようになり、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，Ｓｉ）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を有するものの、熱伝導性に劣るものであるために、切削時発生の高熱で切刃部に偏摩耗の原因となる熱塑性変形が発生し、これが原因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、通常の条件での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。
【図３】（ａ）は被覆超硬チップの概略斜視図、（ｂ）は被覆超硬チップの概略縦断面図である。
【図４】（ａ）は被覆超硬エンドミル概略正面図、（ｂ）は同切刃部の概略横断面図である。
【図５】（ａ）は被覆超硬ドリルの概略正面図、（ｂ）は同溝形成部の概略横断面図である。[0001]
BACKGROUND OF THE INVENTION
This invention has excellent thermal conductivity with a hard coating layer, and also has excellent high-temperature hardness and heat resistance. Therefore, even when performing high-speed cutting of difficult-to-cut materials such as stainless steel with high heat generation. The hard coating layer exhibits excellent heat dissipation, which suppresses the thermoplastic deformation of the cutting edge, and as a result, prevents uneven wear caused by the thermoplastic deformation. The present invention relates to a surface-coated cemented carbide cutting tool (hereinafter referred to as a coated cemented carbide tool) that exhibits high wear resistance.
[0002]
[Prior art]
In general, coated carbide tools are used for throwaway inserts that are detachably attached to the tip of a cutting tool for drilling and cutting of various materials such as steel and cast iron, and for flat cutting. There are drills, miniature drills, solid type end mills used for chamfering, grooving, shoulder processing, etc. in which the cutting blade takes an intermittent cutting form, and the solid type by attaching the throwaway tip detachably A slow-away end mill tool that performs a cutting process in the same manner as an end mill is known.
[0003]
Further, as a coated carbide tool, a substrate made of tungsten carbide (hereinafter referred to as WC) -based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) -based cermet (hereinafter collectively referred to as a cemented carbide substrate). ) On the surface of the composition formula: (Al _{1-(X + Y)} Ti _X Si _Y ) N (wherein, X is 0.30 to 0.45, Y: 0.05 to 0.15 in atomic ratio) A hard coating layer composed of a composite nitride of Al, Ti, and Si (hereinafter referred to as (Al, Ti, Si) N) satisfying the following conditions: physical vapor deposition with an average layer thickness of 1 to 15 μm A hard tool has been proposed, and the coated carbide tool has various high-temperature properties (high-temperature hardness and heat resistance) because the (Al, Ti, Si) N layer constituting the hard coating layer has excellent properties. It is also known that it is used for continuous cutting and interrupted cutting of cast iron and cast iron.
[0004]
Furthermore, the above-mentioned coated carbide tool is, for example, the above-mentioned carbide substrate is inserted into an arc ion plating apparatus which is one type of physical vapor deposition apparatus schematically shown in FIG. For example, an arc discharge is generated between the anode electrode and a cathode electrode (evaporation source) on which an Al—Ti—Si 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 (Al, Ti, Si) N layer.
[0005]
[Problems to be solved by the invention]
In recent years, the performance of cutting devices has been dramatically improved, while on the other hand, there is a strong demand for labor saving, energy saving, and cost reduction for cutting, and with this, cutting tends to be faster. For coated carbide tools, there is no problem when used under normal cutting conditions, but especially when used for high-speed cutting of difficult-to-cut materials such as stainless steel with high heat generation. The part is subject to thermoplastic deformation, and this causes uneven wear, so that the progress of wear is remarkably accelerated and 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 coated carbide tool that does not cause thermoplastic deformation in the cutting edge portion due to high heat generated in high-speed cutting of difficult-to-cut materials. As a result of conducting research by focusing on the hard coating layer that constitutes conventional coated carbide tools,
(A) The (Al, Ti, Si) 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. Arc ion plating apparatus having a structure as shown in FIG. 1 (a) and a schematic front view, for example. A carbide base mounting turntable is provided in the central part of the apparatus, and the Ti—highest content point forming Al—Ti—Si alloy is formed on one side of the turntable, and the Ti component non-containing point forming Al— is set on the other side. Using an arc ion plating apparatus in which all Si alloys are arranged as cathode electrodes (evaporation sources), a plurality of carbide substrates are mounted in a ring shape along the outer periphery of the rotary table of this apparatus. The cathode electrode (evaporation source) on both sides described above is rotated while rotating the rotary table with a nitrogen atmosphere as the inside atmosphere and rotating the carbide substrate itself for the purpose of uniforming the thickness of the hard coating layer to be deposited. When an (Al, Ti, Si) N layer is formed on the surface of the cemented carbide substrate by generating an arc discharge between the anode electrode and the anode electrode, the resulting (Al, Ti, Si) N layer is rotated. When the cemented carbide substrate arranged in a ring shape on the table is closest to the cathode electrode (evaporation source) of the one side Al-Ti-Si alloy, the highest Ti component content point is formed in the layer, Further, when the carbide substrate is closest to the cathode electrode of the Al-Si alloy on the other side, a Ti component-free point is formed in the layer, and in the layer thickness direction in the layer by the rotation of the rotary table. So the T The component highest content point and the Ti component non-contained point appear alternately and repeatedly with a predetermined interval, and the Ti component is contained from the Ti component highest content point to the Ti component non-contained point and from the Ti minimum content point to the Ti component non-contained point. To have a component concentration distribution structure whose amount changes continuously.
[0007]
(B) In the (Al, Ti, Si) N layer having the repeated continuous change component concentration distribution structure of (a) above, Ti in the Al—Ti—Si alloy which is the cathode electrode (evaporation source) on one side facing each other The Si content corresponds to the Ti and Si content of the conventional Al—Ti—Si alloy for forming an Al layer (Al, Ti, Si) N layer, and Al— which is the cathode electrode (evaporation source) on the other side. While making the Si content in the Si alloy the same as the Si content in the Al-Ti-Si alloy, controlling the rotation speed of the turntable on which the carbide substrate is mounted,
The highest Ti component content point is the composition formula: (Al _{1-(X + Y)} Ti _X Si _Y ) N (wherein, X is 0.30 to 0.45 in terms of atomic ratio, Y: 0.05 to 0) .15)
The Ti component-free point is a composition formula: (Al _1-Y Si _Y ) N (however, Y: 0.05 to 0.15 in atomic ratio),
And the distance between the adjacent Ti component highest content point and the Ti component non-contained point in the thickness direction is 0.01 to 0.1 μm,
The above-mentioned Ti component highest content point shows excellent high temperature hardness and heat resistance (high temperature characteristics) corresponding to the high temperature hardness and heat resistance of the conventional (Al, Ti, Si) N layer, while the above Ti component non-content. In the content point portion, (Al, Si) N that does not substantially contain Ti, that is, (Al, Si) N made of AlN having excellent thermal conductivity and containing Si for the purpose of improving heat resistance. Since it is configured, it exhibits extremely high heat dissipation, and the interval between these Ti component highest content point and Ti component non-contained point has been made extremely small, so that it has excellent high temperature characteristics as the characteristics of the entire layer. The coated carbide tool composed of the (Al, Ti, Si) N layer with the hard coating layer is particularly suitable for stainless steel with high heat generation. Even when used for high-speed cutting of difficult-to-cut materials such as stainless steel, the hard coating layer exhibits excellent heat dissipation and removes the high heat generated during cutting, resulting in the occurrence of thermoplastic deformation at the cutting edge. Therefore, normal wear is always maintained in the state of wear of the cutting edge, and acceleration of wear due to uneven wear is suppressed.
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 Ti component highest content point forming Al on one side. -Using an arc ion plating apparatus in which a Ti-Si alloy and an Al-Si alloy for forming a Ti component-free point on the other side are arranged opposite to each other as a cathode electrode (evaporation source), a plurality of A carbide substrate is mounted in a ring shape, and in this state, the atmosphere inside the apparatus is changed to a nitrogen atmosphere, the rotary table is rotated, and the carbide substrate itself is rotated while the cathode electrode (evaporation source) and anode electrodes on both sides are rotated. by generating arc discharge between the surface of the carbide substrate, formed by vapor deposition (Al, Ti, Si) a hard coating layer consisting of N layers in overall average layer thickness of 1~15μm coating In the hard tool,
The hard coating layer has a Ti component highest content point and a Ti component non-content point alternately present at predetermined intervals along the layer thickness direction, and the Ti component is not contained from the Ti component highest content point. Point, having a component concentration distribution structure in which the Ti component content continuously changes from the Ti component-free point to the Ti component highest-containing point,
The highest Ti component content point is the composition formula: (Al _{1-(X + Y)} Ti _X Si _Y ) N (wherein, X is 0.30 to 0.45 in terms of atomic ratio, Y: 0.05 to 0) .15)
The Ti component-free point is a composition formula: (Al _1-Y Si _Y ) N (however, Y: 0.05 to 0.15 in atomic ratio),
And the interval between the adjacent Ti component highest content point and the Ti component non-contained point is 0.01 to 0.1 μm,
It is characterized by a coated carbide tool that exhibits excellent wear resistance with a hard coating layer in high-speed cutting of 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 Ti component highest content point Ti component in Ti component highest content point (Al, Ti, Si) N improves high temperature hardness and heat resistance (high temperature characteristics) in coexistence with Al and Si, Similarly, the Si component has the effect of further improving the heat resistance. Therefore, even if the X value indicating the Ti content ratio is less than 0.30 in terms of the total amount of Al and Si (atomic ratio), Even if the Y value indicating the Si content ratio is also less than 0.05, a desired improvement effect cannot be obtained in the high temperature characteristics. On the other hand, even if the X value exceeds 0.45, the Y value is 0.15. Even if it exceeds, since the decreasing tendency appears in the high temperature characteristics, the X value was set to 0.30 to 0.45, and the Y value was set to 0.05 to 0.15.
[0010]
(B) Composition of Ti component-free point The Si component in (Al, Si) N at the Ti component-free point improves the heat resistance of AlN having excellent thermal conductivity as described above, and generates high heat. It is included for the purpose of adapting to high-speed cutting of difficult-to-cut materials. Therefore, if the Y value is less than 0.05, the desired heat resistance improvement effect cannot be obtained, whereas if the Y value exceeds 0.15, the Ti component is not present. The Y value was determined to be 0.05 to 0.15 because a tendency toward a decrease in the thermal conductivity of the contained point appears and it becomes difficult to exhibit a desired excellent heat dissipation effect.
[0011]
(C) Interval between Ti component highest content point and Ti 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. It is impossible to ensure excellent high temperature characteristics and thermal conductivity, and if the interval exceeds 0.1 μm, each point has a defect, that is, if the Ti component is the highest content point, thermal conductivity is insufficient, Ti component If it is a non-contained point, insufficient high-temperature characteristics appear locally in the layer, and this causes the cutting edge portion to easily undergo thermoplastic deformation and promotes the progress of wear. .01-0.1 μm.
[0012]
(D) Overall average layer thickness of hard coating layer If the layer thickness is less than 1 μm, desired wear resistance cannot be ensured. On the other hand, if the average layer thickness exceeds 15 μm, chipping tends to occur. Therefore, the average layer thickness was determined to be 1 to 15 μm.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Next, the coated carbide tool of the present invention will be specifically described with reference to examples.
Example 1
As raw material powders, WC powder, TiC powder, VC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, and Co powder, all having an average particle diameter of 1 to 3 μm, were prepared. And then wet-mixed with a ball mill for 72 hours, dried, and press-molded into a green compact at a pressure of 100 MPa. The green compact was vacuumed at 6 Pa at a temperature of 1400 ° C. for 1 hour. Sintered under the holding conditions, and after sintering, the cutting edge portion was subjected to a honing process of R: 0.03, and the carbide bases A1 to A10 made of WC-based cemented carbide having ISO / CNMG120408 chip shape Formed.
[0014]
In addition, as raw material powders, all are TiCN (weight ratio TiC / TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC powder having an average particle diameter of 0.5 to 2 μm. Co powder and Ni powder are prepared, and these raw material powders are blended in the blending composition shown in Table 2, wet mixed by a ball mill for 24 hours, dried, and then pressed into a compact at a pressure of 100 MPa. The green compact was sintered in a nitrogen atmosphere of 2 kPa at a temperature of 1500 ° C. for 1 hour, and after sintering, the cutting edge portion was subjected to a honing process of R: 0.03 to obtain ISO standard / CNMG120408. TiCN-based cermet carbide substrates B1 to B6 having the following chip shape were formed.
[0015]
Next, each of the above-mentioned carbide substrates A1 to A10 and B1 to B6 is ultrasonically cleaned in acetone and dried, on the rotary table in the arc ion plating apparatus shown in FIG. Therefore, as a cathode electrode (evaporation source) on one side, an Al-Ti-Si alloy for forming the highest content point of Ti component having various component compositions, and a Ti component not used as the cathode electrode (evaporation source) on the other side. The Al-Si alloy for forming the contained points is placed opposite to the rotary table, and the metal Ti for bombard cleaning is also mounted. First, the apparatus is evacuated and kept at a vacuum of 0.5 Pa or less with a heater. After heating the inside of the apparatus to 500 ° C., a DC bias voltage of −1000 V is applied to a carbide substrate that rotates while rotating on the rotary table, and the metal Ti and anode of the cathode electrode are applied. A current of 100 A is passed between the cathode electrode and arc discharge 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 form a reaction atmosphere of 2 Pa. A -100 V DC bias voltage is applied to the carbide substrate rotating while rotating on the rotary table, and each cathode electrode (the Al-Ti-Si alloy for forming the highest Ti component point and the Ti component-free point formation) is applied. A current of 100 A is passed between the Al-Si alloy) and the anode electrode to generate an arc discharge, 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. Ti component highest content point and Ti component non-contained point alternately and repeatedly exist at the target intervals shown in Tables 3 and 4, and from the Ti component highest content point, the Ti component non-contained point, A hard coating layer having a component concentration distribution structure in which the Ti component content continuously changes from the Ti component non-contained point to the Ti component maximum containing point, and also having the target total layer thickness 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]
Further, for the purpose of comparison, these carbide substrates A1 to A10 and B1 to B6 are ultrasonically cleaned in acetone and dried, and then loaded into a normal arc ion plating apparatus shown in FIG. Attached are Al-Ti-Si alloys having various components as cathode electrodes (evaporation sources), and are also equipped with bombard cleaning metal Ti. First, the apparatus is evacuated to a vacuum of 0.5 Pa or less. While being held, the inside of the apparatus was heated to 500 ° C. with a heater, a DC bias voltage of −1000 V was applied to the cemented carbide substrate, and a current of 100 A was passed between the metal Ti of the cathode electrode and the anode electrode. An arc discharge is generated, and the surface of the carbide substrate is cleaned by Ti bombardment. Then, nitrogen gas is introduced into the apparatus as a reaction gas to form a reaction atmosphere of 2 Pa. The bias voltage applied to the body 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 carbide substrates A1 to A10 and B1 to B6 is changed to Table 5, By vapor-depositing a hard coating layer composed of an (Al, Ti, Si) N layer having the target composition and the target layer thickness shown in FIG. The conventional surface-coated cemented carbide throwaway tips (hereinafter referred to as conventional coated carbide tips) 1 to 16 as the conventional coated carbide tools having the shape shown in FIG.
[0017]
Next, with the present invention coated carbide tips 1-16 and conventional coated carbide tips 1-16, in a state where this is screwed to the tip of the tool steel tool with a fixing jig,
Work material: JIS / SUS304 round bar,
Cutting speed: 250 m / min. ,
Cutting depth: 1mm,
Feed: 0.25 mm / rev. ,
Cutting time: 10 minutes,
Stainless steel dry continuous high speed cutting test under the conditions of
Work material: JIS / SUS304 lengthwise equidistant four round grooved round bars,
Cutting speed: 200 m / min. ,
Incision: 1.5mm,
Feed: 0.2 mm / rev. ,
Cutting time: 4 minutes
Stainless steel dry interrupted high-speed cutting test,
Work material: JIS / SCMnH2 round bar,
Cutting speed: 150 m / min. ,
Cutting depth: 1mm,
Feed: 0.2 mm / rev. ,
Cutting time: 10 minutes,
The dry continuous high-speed cutting test of high-manganese steel under the above conditions was performed, 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 m of three kinds of sintered carbide rod forming bodies for forming a carbide substrate, and by grinding from the above three kinds of round bar sintered bodies, the combinations shown in Table 8 and the diameter of the cutting edge portion X Carbide substrates (end mills) C-1 to C-8 having lengths of 6 mm x 13 mm, 10 mm x 22 mm, and 20 mm x 45 mm, respectively, were produced.
[0026]
Then, these carbide substrates (end mills) C-1 to C-8 were ultrasonically washed in acetone and dried, and then charged into the arc ion plating apparatus shown in FIG. Under the same conditions as in Example 1, the Ti component highest content point and Ti component non-contained point of the target composition shown in Table 9 along the layer thickness direction are alternately present at the target interval shown in Table 9 alternately, And having a component concentration distribution structure in which the Ti component content continuously changes from the Ti component highest content point to the Ti component non-content point, from the Ti component non-content point to the Ti component highest content point, and By depositing a hard coating layer having a target overall layer thickness shown in FIG. 9, the present invention has 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). Surface-coated carbide of the present invention as a coated carbide tool Gold end mill (hereinafter, the present invention refers to the coating end mills) 1-8 were prepared, respectively.
[0027]
For the purpose of comparison, the above-mentioned carbide substrates (end mills) C-1 to C-8 are ultrasonically cleaned in acetone and dried, and the ordinary arc ion plating apparatus shown in FIG. 2 is also used. And having the target composition and target layer thickness shown in Table 10 under the same conditions as in Example 1 and substantially no composition change along the layer thickness direction (Al, Ti, Si) ) End coat mills made of conventional surface-coated cemented carbide (hereinafter referred to as conventional coated cemented carbide end mills) 1 to 8 as conventional coated cemented carbide tools were produced by vapor-depositing a hard coating layer consisting of N layers.
[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 / SCMnH2 plate material,
Cutting speed: 80 m / min. ,
Groove depth (cut): 1mm,
Table feed: 240 mm / min,
With respect to the dry high-speed grooving test of high manganese 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: 100 m / min. ,
Groove depth (cut): 2.5 mm,
Table feed: 240 mm / min,
For the dry high-speed grooving 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: 100 m / min. ,
Groove depth (cut): 5.0 mm,
Table feed: 120 mm / min,
Stainless steel dry type high-speed grooving test is performed under the above conditions. In any grooving test, the flank wear width of the outer peripheral edge of the cutting edge reaches 0.1 mm, which is a guide for the service life. The cutting groove length 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)
The diameters produced in Example 2 above were 8 mm (for forming carbide substrates C-1 to C-3), 13 mm (for forming carbide substrates C-4 to C-6), and 26 mm (for carbide substrates C-). 7, for C-8 formation), from these three types of round bar sintered bodies, the diameter x length of the groove forming portion is 4 mm x 13 mm (by grinding), respectively. Carbide substrates D-1 to D-3), 8 mm × 22 mm (Carbide substrates D-4 to D-6), and 16 mm × 45 mm (Carbide substrates D-7, D-8) Hard substrates (drills) D-1 to D-8 were produced, respectively.
[0033]
Next, the cutting edges of these carbide substrates (drills) D-1 to D-8 are subjected to honing, ultrasonically cleaned in acetone and dried, and the arc ion plating apparatus shown in FIG. 1 is also used. In the same conditions as in Example 1 above, the Ti component highest content point and Ti component non-contained point of the target composition shown in Table 11 along the layer thickness direction are also shown in Table 11 alternately. Component concentration distribution structure that repeatedly exists at a target interval, and in which the Ti component content continuously changes from the Ti component highest content point to the Ti component non-content point, and from the Ti component non-content point to the Ti component highest content point And a hard coating layer having a target total layer thickness also shown in Table 11 is vapor-deposited in a schematic front view in FIG. 5A and in a schematic cross-sectional view of the groove forming portion in FIG. The invention coated carbide with the shape shown The present invention surface coating cemented carbide drill as (hereinafter, the present invention refers to the coating carbide drills) 1-8 were prepared, respectively.
[0034]
For comparison purposes, the cutting edges of the above-mentioned carbide substrates (drills) D-1 to D-8 are honed, ultrasonically cleaned in acetone, and dried, as shown in FIG. The sample was charged into a normal arc ion plating apparatus, had the target composition and target layer thickness shown in Table 12 under the same conditions as in Example 1, and substantially changed in composition along the layer thickness direction. Conventional surface-coated cemented carbide drills (hereinafter referred to as conventional coated carbide drills) 1 to 8 as conventional coated carbide tools are deposited by vapor-depositing a hard coating layer comprising no (Al, Ti, Si) N layer. Were manufactured respectively.
[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: 60 m / min. ,
Feed: 0.1 mm / rev,
Hole depth: 4mm
For the wet high speed 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 / SCMnH2 plate material,
Cutting speed: 55 m / min. ,
Feed: 0.1 mm / rev,
Hole depth: 8mm
For high-manganese steel wet high speed drilling cutting test under the conditions of the present invention, the coated carbide drills 7 and 8 of the present invention and the conventional coated carbide drills 7 and 8,
Work material: Plane size: 100 mm × 250 mm, thickness: 50 mm JIS / SUS316 plate material,
Cutting speed: 60 m / min. ,
Feed: 0.1 mm / rev,
Hole depth: 16mm
Each of the wet high speed drilling cutting test of stainless steel under the above conditions is performed, and the flank wear width of the tip cutting edge surface reaches 0.3 mm in any wet high speed drilling cutting 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 Ti component highest content point and Ti component non-contained point, as well as conventional coated carbide tips 1-16, conventional coated carbide end mills 1-8, and conventional coated carbide drills 1-8 as conventional coated carbide tools 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 highest Ti component-containing point and the Ti component-free point in the hard coating layer of these coated carbide tools of the present invention, the overall 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 a Ti component highest content point having excellent high-temperature hardness and heat resistance in the layer thickness direction, and a Ti component-free point having excellent heat dissipation (thermal conductivity). Are alternately present at predetermined intervals, and the Ti component content is continuously from the Ti component highest content point to the Ti component non-content point, and from the Ti component non-content point to the Ti component highest content point. The coated carbide tool of the present invention having a varying component concentration distribution structure has an excellent hard coating layer even when used in high-speed cutting of stainless steel and high manganese steel, which are difficult-to-cut materials with high heat generation. Since it exhibits heat dissipation and the cutting edge is not overheated by the high heat generated during cutting, the occurrence of thermoplastic deformation is also suppressed, and the cutting edge always shows a normal wear form, providing excellent resistance. It shows wear On the other hand, in the conventional coated carbide tool in which the hard coating layer is composed of an (Al, Ti, Si) N layer having substantially no composition change along the layer thickness direction, the hard coating layer has excellent high-temperature hardness and heat resistance. However, because it is inferior in thermal conductivity, the high heat generated during cutting causes thermoplastic deformation that causes uneven wear in the cutting edge, which significantly accelerates wear progress. It is clear that the service life is reached in a relatively short time.
As described above, the coated carbide tool of the present invention has excellent wear resistance for a long time, not only for cutting under normal conditions, but also for high-speed cutting of difficult-to-cut materials such as stainless steel. Therefore, it is possible to sufficiently satisfy the labor-saving and energy-saving of the cutting process and the cost reduction.
[Brief description of the drawings]
FIG. 1 shows an arc ion plating apparatus used for forming a hard coating layer constituting a coated carbide tool of the present invention, wherein (a) is a schematic plan view and (b) is a schematic front view.
FIG. 2 is a schematic explanatory view of a normal arc ion plating apparatus used to form a hard coating layer constituting a conventional coated carbide tool.
FIG. 3A is a schematic perspective view of a coated carbide chip, and FIG. 3B is a schematic longitudinal sectional view of the coated carbide chip.
4A is a schematic front view of a coated carbide end mill, and FIG. 4B is a schematic cross-sectional view of the cutting edge portion.
5A is a schematic front view of a coated carbide drill, and FIG. 5B is a schematic cross-sectional view of the groove forming portion.

Claims

A rotating table for mounting either or both of a tungsten carbide base cemented carbide substrate and a titanium carbonitride-based cermet substrate is provided at the center of the apparatus, and the Ti component highest content point forming Al is formed on one side of the rotating table. -Using an arc ion plating apparatus in which a Ti-Si alloy and an Al-Si alloy for forming Ti component-free points on the other side are arranged to face each other as a cathode electrode (evaporation source), The base is mounted in a ring shape, and in this state, the atmosphere inside the apparatus is changed to a nitrogen atmosphere, the rotary table is rotated, and the base itself is rotated while the cathode electrode (evaporation source) and the anode electrode on both sides are rotated. by generating arc discharge between the surface of the substrate, all of 1~15μm a hard layer made of a composite nitride layer of Al, Ti, and Si In the surface-coated cemented carbide cutting tool comprising depositing an average layer thickness,
The hard coating layer has a Ti component highest content point and a Ti component non-content point alternately present at predetermined intervals along the layer thickness direction, and the Ti component is not contained from the Ti component highest content point. Point, having a component concentration distribution structure in which the Ti component content continuously changes from the Ti component-free point to the Ti component highest-containing point,
The highest Ti component content point is the composition formula: (Al _{1-(X + Y)} Ti _X Si _Y ) N (wherein the atomic ratio, X is 0.30 to 0.45, Y: 0.05 to 0) .15)
The Ti component-free point is a composition formula: (Al _{1 -Y} Si _Y ) N (however, Y: 0.05 to 0.15 in atomic ratio),
The distance between the adjacent Ti component highest content point and the adjacent Ti component non-contained point is 0.01 to 0.1 μm,
A surface-coated cemented carbide cutting tool that exhibits excellent wear resistance due to its hard coating layer in high-speed cutting of difficult-to-cut materials.