JP4029323B2 - Surface coated cemented carbide cutting tool with excellent chipping resistance with hard coating layer under high speed heavy cutting conditions - Google Patents
Surface coated cemented carbide cutting tool with excellent chipping resistance with hard coating layer under high speed heavy cutting conditions Download PDFInfo
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【０００１】
【発明の属する技術分野】
この発明は、硬質被覆層が高強度と高靭性を有し、かつ高温硬さと耐熱性にもすぐれ、したがって特に各種の鋼や鋳鉄などの高速切削加工を、高い機械的衝撃を伴う高切り込みや高送りなどの重切削条件で行なった場合にも、硬質被覆層がすぐれた耐チッピング性を発揮する表面被覆超硬合金製切削工具（以下、被覆超硬工具という）に関するものである。
【０００２】
【従来の技術】
一般に、被覆超硬工具には、各種の鋼や鋳鉄などの被削材の旋削加工や平削り加工にバイトの先端部に着脱自在に取り付けて用いられるスローアウエイチップ、穴あけ切削加工などに用いられるドリルやミニチュアドリル、さらに面削加工や溝加工、肩加工などに用いられるソリッドタイプのエンドミルなどがあり、また前記スローアウエイチップを着脱自在に取り付けて前記ソリッドタイプのエンドミルと同様に切削加工を行うスローアウエイエンドミル工具などが知られている。
【０００３】
また、被覆超硬工具として、炭化タングステン（以下、ＷＣで示す）基超硬合金または炭窒化チタン（以下、ＴｉＣＮで示す）基サーメットからなる基体（以下、これらを総称して超硬基体と云う）の表面に、組成式：（Ｔｉ1 -(X+Z)ＡｌX ＣｒZ）Ｎ（ただし、原子比で、Ｘは０．４５〜０．６５、Ｚ：０．０１〜０．１５を示す）を満足するＴｉとＡｌとＣｒの複合窒化物［以下、（Ｔｉ，Ａｌ，Ｃｒ）Ｎで示す］層からなる硬質被覆層を１〜１５μｍの平均層厚で物理蒸着してなる被覆超硬工具が提案され、かかる被覆超硬工具が、硬質被覆層を構成する前記（Ｔｉ，Ａｌ，Ｃｒ）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、高熱発生を伴う各種の鋼や鋳鉄などの高速連続切削や高速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Ｔｉ−Ａｌ−Ｃｒ合金がセットされたカソード電極（蒸発源）との間に、例えば電流：９０Ａの条件でアーク放電を発生させ、同時に装置内に反応ガスとして窒素ガスを導入して、例えば２Ｐａの反応雰囲気とし、一方上記超硬基体には、例えば−１００Ｖのバイアス電圧を印加した条件で、前記超硬合金基体の表面に、上記（Ｔｉ，Ａｌ，Ｃｒ）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、高切り込みや高送りなどの重切削条件での切削加工でもすぐれた切削性能を発揮する被覆超硬工具が強く求められているが、上記の従来被覆超硬工具においては、これを通常の高速切削加工条件で用いた場合には問題はないが、高速切削加工を高い機械的衝撃を伴う高切り込みや高送りなどの重切削条件で行なった場合には、特に硬質被覆層の強度および靭性不足が原因でチッピング（微小割れ）が発生し易く、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、特に高速重切削加工で硬質被覆層がすぐれた耐チッピング性を発揮する被覆超硬工具を開発すべく、上記の従来被覆超硬工具を構成する硬質被覆層に着目し、研究を行った結果、
（ａ）上記の図２に示されるアークイオンプレーティング装置を用いて形成された従来被覆超硬工具を構成する（Ｔｉ，Ａｌ，Ｃｒ）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、一方側に相対的にＡｌ含有量の高いＡｌ成分最高含有点形成用Ｔｉ−Ａｌ−Ｃｒ合金、他方側にＡｌ成分最低含有点形成用Ｔｉ−Ａｌ−Ｃｒ合金をいずれもカソード電極（蒸発源）として対向配置したアークイオンプレーティング装置を用い、この装置の前記回転テーブルの外周部に沿って複数の超硬基体をリング状に装着し、この状態で装置内雰囲気を窒素雰囲気として前記回転テーブルを回転させると共に、蒸着形成される硬質被覆層の層厚均一化を図る目的で超硬基体自体も自転させながら、前記の両側のカソード電極（蒸発源）とアノード電極との間にアーク放電を発生させて、前記超硬基体の表面に（Ｔｉ，Ａｌ，Ｃｒ）Ｎ層を形成すると、この結果の（Ｔｉ，Ａｌ，Ｃｒ）Ｎ層においては、回転テーブル上にリング状に配置された前記超硬基体が上記の一方側のＴｉ−Ａｌ−Ｃｒ合金のカソード電極（蒸発源）に最も接近した時点で層中にＡｌ成分最高含有点が形成され、また前記超硬基体が上記の他方側のＴｉ−Ａｌ−Ｃｒ合金のカソード電極に最も接近した時点で層中にＡｌ成分最低含有点が形成され、上記回転テーブルの回転によって層中には層厚方向にそって前記Ａｌ成分最高含有点とＡｌ成分最低含有点が所定間隔をもって交互に繰り返し現れると共に、前記Ａｌ成分最高含有点から前記Ａｌ成分最低含有点、前記Ａｌ最低含有点から前記Ａｌ成分最低含有点へＡｌ成分含有量が連続的に変化する成分濃度分布構造をもつようになること。
【０００７】
（ｂ）上記（ａ）の繰り返し連続変化成分濃度分布構造の（Ｔｉ，Ａｌ，Ｃｒ）Ｎ層において、対向配置の一方側のカソード電極（蒸発源）であるＴｉ−Ａｌ−Ｃｒ合金におけるＡｌおよびＣｒ含有量を上記の従来（Ｔｉ，Ａｌ，Ｃｒ）Ｎ層形成用Ｔｉ−Ａｌ−Ｃｒ合金のＡｌおよびＣｒ含有量に相当するものとし、同他方側のカソード電極（蒸発源）であるＴｉ−Ａｌ−Ｃｒ合金におけるＡｌ含有量を上記の従来Ｔｉ−Ａｌ−Ｃｒ合金のＡｌ含有量に比して相対的に低いものとすると共に、超硬基体が装着されている回転テーブルの回転速度を制御して、
上記Ａｌ成分最高含有点が、組成式：（Ｔｉ1-(X+Z)ＡｌX ＣｒZ）Ｎ（ただし、原子比で、Ｘは０．４５〜０．５５、Ｚ：０．０１〜０．１０を示す）、
上記Ａｌ成分最低含有点が、組成式：（Ｔｉ1-(X+Z)ＡｌX ＣｒZ）Ｎ（ただし、原子比で、Ｘは０．１５〜０．４０、Ｚ：０．０１〜０．１５を示す）、
を満足し、かつ隣り合う上記Ａｌ成分最高含有点とＡｌ成分最低含有点の厚さ方向の間隔を０．０１〜０．１μmとすると、
上記Ａｌ成分最高含有点部分では、上記の従来（Ｔｉ，Ａｌ，Ｃｒ）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Ａｌ成分最低含有点部分では、前記Ａｌ成分最高含有点部分に比してＡｌ含有量が低く、Ｔｉ含有量の高いものとなるので、一段と高い強度と靭性が確保され、かつこれらＡｌ成分最高含有点とＡｌ成分最低含有点の間隔をきわめて小さくしたことから、層全体の特性としてすぐれた高温特性を保持した状態で一段とすぐれた強度と靭性を具備するようになり、したがって、硬質被覆層がかかる構成の（Ｔｉ，Ａｌ，Ｃｒ）Ｎ層からなる被覆超硬工具は、特に各種の鋼や鋳鉄などの高速切削加工を、高い機械的衝撃を伴う高切り込みや高送りなどの重切削条件で行なった場合にも、硬質被覆層がすぐれた耐チッピング性を発揮するようになること。
以上（ａ）および（ｂ）に示される研究結果を得たのである。
【０００８】
この発明は、上記の研究結果に基づいてなされたものであって、超硬基体の表面に、（Ｔｉ，Ａｌ，Ｃｒ）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、Ａｌ成分最高含有点とＡｌ成分最低含有点とが所定間隔をおいて交互に繰り返し存在し、かつ前記Ａｌ成分最高含有点から前記Ａｌ成分最低含有点、前記Ａｌ成分最低含有点から前記Ａｌ成分最高含有点へＡｌ成分含有量が連続的に変化する成分濃度分布構造を有し、
さらに、上記Ａｌ成分最高含有点が、組成式：（Ｔｉ1-(X+ Ｚ )ＡｌX ＣｒZ）Ｎ（ただし、原子比で、Ｘは０．４５〜０．５５、Ｚ：０．０１〜０．１０を示す）、
上記Ａｌ成分最低含有点が、組成式：（Ｔｉ1-(X+Z)ＡｌX ＣｒZ）Ｎ（ただし、原子比で、Ｘは０．１５〜０．４０、Ｚ：０．０１〜０．１５を示す）、
を満足し、かつ隣り合う上記Ａｌ成分最高含有点とＡｌ成分最低含有点の間隔が、０．０１〜０．１μmである、
高速重切削条件で硬質被覆層がすぐれた耐チッピング性を発揮する被覆超硬工具に特徴を有するものである。
【０００９】
つぎに、この発明の被覆超硬工具において、これを構成する硬質被覆層の構成を上記の通りに限定した理由を説明する。
（ａ）Ａｌ成分最高含有点の組成
Ａｌ成分最高含有点の（Ｔｉ，Ａｌ，Ｃｒ）ＮにおけるＴｉ成分は、強度および靭性を向上させ、同Ａｌ成分は、高温硬さおよび耐熱性（高温特性）を向上させ、さらにＣｒ成分は一段と耐熱性を向上させる作用があり、したがってＡｌおよびＣｒ成分の含有割合が高くなればなるほど高温特性は向上したものになり、高熱発生を伴う高速切削に適応したものになるが、Ａｌの含有割合を示すＸ値がＴｉとＣｒの合量に占める割合（原子比）で０．５５を越え、またＣｒの含有割合を示すＺ値が同０．１０を越えても、高強度および高靭性を有するＡｌ成分最低含有点が隣接して存在しても層自体の強度および靭性の低下が避けられない場合が生じ、この結果チッピングなどが発生し易くなり、一方同Ｘ値が同０．４５未満でも、また同Ｚ値が０．０１未満でも前記高温特性に所望の向上効果が得られないことから、Ｘ値を０．４５〜０．５５、Ｚ値を０．０１〜０．１０と定めた。
【００１０】
（ｂ）Ａｌ成分最低含有点の組成
上記の通りＡｌ成分最高含有点は高温特性のすぐれたものであるが、反面強度および靭性の劣るものであるため、このＡｌ成分最高含有点の強度および靭性不足を補う目的で、Ｔｉ含有割合が高く、一方Ａｌ含有量が低く、これによって高強度および高靭性を有するようになるＡｌ成分最低含有点を厚さ方向に交互に介在させるものであり、したがってＡｌの割合を示すＸ値がＴｉおよびＣｒ成分との合量に占める割合（原子比）で０．４０を越えると、所望のすぐれた強度および靭性を確保することができず、一方同Ｘ値が０．１５未満になると、Ａｌ成分最低含有点に所望の高温特性を具備せしめることができなくなることから、Ａｌ成分最低含有点でのＡｌの割合を示すＸ値を０．１５〜０．４０と定めた。
Ａｌ成分最低含有点におけるＣｒ成分も、上記の通りＡｌ成分との共存で耐熱性を向上させ、もって高熱発生を伴う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Ｚ値が０．０１未満では所望の耐熱性向上効果が得られず、一方Ｚ値が０．１５を越えるとＡｌ成分最低含有点での強度および靭性に低下傾向が現れるようになり、所望の耐チッピング性向上が困難になることから、Ｚ値を０．０１〜０．１５と定めた。
【００１１】
（ｃ）Ａｌ成分最高含有点とＡｌ成分最低含有点間の間隔
その間隔が０．０１μm未満ではそれぞれの点を上記の組成で明確に形成することが困難であり、この結果層に所望の高温特性と強度および靭性を確保することができなくなり、またその間隔が０．１μmを越えるとそれぞれの点がもつ欠点、すなわちＡｌ成分最高含有点であれば強度および靭性不足、Ａｌ成分最低含有点であれば高温特性不足が層内に局部的に現れ、これが原因でチッピングが発生し易くなったり、摩耗進行が促進されるようになることから、その間隔を０．０１〜０．１μmと定めた。
【００１２】
（ｄ）硬質被覆層の全体平均層厚
その層厚が１μｍ未満では、所望の耐摩耗性を確保することができず、一方その平均層厚が１５μｍを越えると、チッピングが発生し易くなることから、その平均層厚を１〜１５μｍと定めた。
【００１３】
【発明の実施の形態】
つぎに、この発明の被覆超硬工具を実施例により具体的に説明する。
（実施例１）
原料粉末として、いずれも１〜３μｍの平均粒径を有するＷＣ粉末、ＴｉＣ粉末、ＴａＣ粉末、ＮｂＣ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Ａ−２〜Ａ−４、Ａ−６、およびＡ−１０をそれぞれ形成した。
【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、Ｍｏ2 Ｃ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Ｂ−１、Ｂ−４、およびＢ−６をそれぞれ形成した。
【００１５】
ついで、上記の超硬基体Ａ−２〜Ａ−４、Ａ−６、およびＡ−１０、並びにＢ−１、Ｂ−４、およびＢ−６のそれぞれを、アセトン中で超音波洗浄し、乾燥した状態で、図１に示されるアークイオンプレーティング装置内の回転テーブル上に外周部にそって装着し、一方側のカソード電極（蒸発源）として、種々の成分組成をもったＡｌ成分最高含有点形成用Ｔｉ−Ａｌ−Ｃｒ合金、他方側のカソード電極（蒸発源）としてＡｌ成分最低含有点形成用Ｔｉ−Ａｌ−Ｃｒ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、かつカソード電極の前記金属Ｔｉとアノード電極との間に１００Ａの電流を流してアーク放電を発生させ、もって超硬基体表面を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、かつそれぞれのカソード電極(前記Ａｌ成分最高含有点形成用Ｔｉ−Ａｌ−Ｃｒ合金およびＡｌ成分最低含有点形成用Ｔｉ−Ａｌ−Ｃｒ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に示される目標組成のＡｌ成分最高含有点とＡｌ成分最低含有点とが交互に同じく表３に示される目標間隔で繰り返し存在し、かつ前記Ａｌ成分最高含有点から前記Ａｌ成分最低含有点、前記Ａｌ成分最低含有点から前記Ａｌ成分最高含有点へＡｌ成分含有量が連続的に変化する成分濃度分布構造を有し、かつ同じく表３に示される目標全体層厚の硬質被覆層を蒸着することにより、本発明被覆超硬工具としての本発明表面被覆超硬合金製スローアウエイチップ（以下、本発明被覆超硬チップと云う）１〜８をそれぞれ製造した。
【００１６】
また、比較の目的で、これら超硬基体Ａ−２〜Ａ−４、Ａ−６、およびＡ−１０、並びにＢ−１、Ｂ−４、およびＢ−６を、アセトン中で超音波洗浄し、乾燥した状態で、それぞれ図２に示される通常のアークイオンプレーティング装置に装入し、カソード電極（蒸発源）として種々の成分組成をもったＴｉ−Ａｌ−Ｃｒ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、かつカソード電極の前記金属Ｔｉとアノード電極との間に１００Ａの電流を流してアーク放電を発生させ、もって超硬基体表面を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のそれぞれの表面に、表４に示される目標組成および目標層厚を有し、かつ層厚方向に沿って実質的に組成変化のない（Ｔｉ，Ａｌ，Ｃｒ）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）１〜８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１〜８および従来被覆超硬チップ１〜８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：３５０ｍ／ｍｉｎ．、
切り込み：６ｍｍ、
送り：０．３５ｍｍ／ｒｅｖ．、
切削時間：５分、
の条件でのステンレス鋼の湿式連続高速高切り込み切削加工試験、
被削材：ＪＩＳ・Ｓ５０Ｃの長さ方向等間隔４本縦溝入り丸棒、
切削速度：３５０ｍ／ｍｉｎ．、
切り込み：３ｍｍ、
送り：０．８ｍｍ／ｒｅｖ．、
切削時間：１０分、
の条件での炭素鋼の乾式断続高速高送り切削加工試験、さらに、
被削材：ＪＩＳ・ＳＮＣＭ４３９の丸棒、
切削速度：３５０ｍ／ｍｉｎ．、
切り込み：６ｍｍ、
送り：０．４ｍｍ／ｒｅｖ．、
切削時間：５分、
の条件での合金鋼の乾式連続高速高切り込み切削加工試験を行い、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５に示した。
【００１８】
【表１】
【表２】
【表３】
【表４】
【表５】
（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６に示される配合組成に配合し、さらにワックスを加えてアセトン中で２４時間ボールミル混合し、減圧乾燥した後、１００ＭＰａの圧力で所定形状の各種の圧粉体にプレス成形し、これらの圧粉体を、６Ｐａの真空雰囲気中、７℃／分の昇温速度で１３７０〜１４７０℃の範囲内の所定の温度に昇温し、この温度に１時間保持後、炉冷の条件で焼結して、直径が８ｍｍ、１３ｍｍ、および２６ｍｍの３種の超硬基体形成用丸棒焼結体Ｃ−１、Ｃ−２、Ｃ−４、Ｃ−５、およびＣ−７を形成し、さらに前記の３種の丸棒焼結体のうちの丸棒焼結体Ｃ−１、Ｃ−２，Ｃ−５，およびＣ−７を用い、これから、研削加工にて、表６に示される組合せで、切刃部の直径×長さがそれぞれ６ｍｍ×１３ｍｍ、１０ｍｍ×２２ｍｍ、および２０ｍｍ×４５ｍｍの寸法、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エンドミル超硬基体をそれぞれ製造した。
【００２４】
ついで、これらのエンドミル超硬基体を、アセトン中で超音波洗浄し、乾燥した状態で、同じく図１に示されるアークイオンプレーティング装置に装入し、上記実施例１と同一の条件で、層厚方向に沿って表７に示される目標組成のＡｌ成分最高含有点とＡｌ成分最低含有点とが交互に同じく表７に示される目標間隔で繰り返し存在し、かつ前記Ａｌ成分最高含有点から前記Ａｌ成分最低含有点、前記Ａｌ成分最低含有点から前記Ａｌ成分最高含有点へＡｌ成分含有量が連続的に変化する成分濃度分布構造を有し、かつ同じく表７に示される目標全体層厚の硬質被覆層を蒸着することにより、本発明被覆超硬工具としての本発明表面被覆超硬合金製エンドミル（以下、本発明被覆超硬エンドミルと云う）１〜４をそれぞれ製造した。
【００２５】
また、比較の目的で、上記のエンドミル超硬基体を、アセトン中で超音波洗浄し、乾燥した状態で、同じく図２に示される通常のアークイオンプレーティング装置に装入し、上記実施例１と同一の条件で、表８に示される目標組成および目標層厚を有し、かつ層厚方向に沿って実質的に組成変化のない（Ｔｉ，Ａｌ，Ｃｒ）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）１〜４をそれぞれ製造した。
【００２６】
つぎに、上記本発明被覆超硬エンドミル１〜４および従来被覆超硬エンドミル１〜４のうち、本発明被覆超硬エンドミル１，２および従来被覆超硬エンドミル１，２については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＳＫＤ６１の板材、
切削速度：１２０ｍ／ｍｉｎ．、
溝深さ（切り込み）：９ｍｍ、
テーブル送り：１４００ｍｍ／分、
の条件での工具鋼の乾式高速高切り込み溝切削加工試験、本発明被覆超硬エンドミル３および従来被覆超硬エンドミル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：１２０ｍ／ｍｉｎ．、
溝深さ（切り込み）：１５ｍｍ、
テーブル送り：８３０ｍｍ／分、
の条件でのステンレス鋼の乾式高速高切り込み溝切削加工試験、本発明被覆超硬エンドミル４および従来被覆超硬エンドミル４については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＳＣＭ４４０の板材、
切削速度：１５０ｍ／ｍｉｎ．、
溝深さ（切り込み）：１０ｍｍ、
テーブル送り：５４０ｍｍ／分、
の条件での合金鋼の乾式高速高送り溝切削加工試験をそれぞれ行い、いずれの溝切削加工試験でも切刃部の外周刃の逃げ面摩耗幅が使用寿命の目安とされる０．１ｍｍに至るまでの切削溝長を測定した。この測定結果を表７，８にそれぞれ示した。
【００２７】
【表６】
【表７】
【表８】
（実施例３）
上記の実施例２で製造した直径が８ｍｍ、１３ｍｍ、および２６ｍｍの３種の丸棒焼結体のうちの丸棒焼結体Ｃ−２，Ｃ−４，Ｃ−５，およびＣ−７を用い、これから、研削 加工にて、表６に示される組合せで、溝形成部の直径×長さがそれぞれ４ｍｍ×１３ｍｍ、８ｍｍ×２２ｍｍ、および１６ｍｍ×４５ｍｍの寸法、並びにいずれもねじれ角３０度の２枚刃形状をもったドリル超硬基体をそれぞれ製造した。
【００３１】
ついで、これらのドリル超硬基体の切刃に、ホーニングを施し、アセトン中で超音波洗浄し、乾燥した状態で、同じく図１に示されるアークイオンプレーティング装置に装入し、上記実施例１と同一の条件で、層厚方向に沿って表９に示される目標組成のＡｌ成分最高含有点とＡｌ成分最低含有点とが交互に同じく表９に示される目標間隔で繰り返し存在し、かつ前記Ａｌ成分最高含有点から前記Ａｌ成分最低含有点、前記Ａｌ成分最低含有点から前記Ａｌ成分最高含有点へＡｌ成分含有量が連続的に変化する成分濃度分布構造を有し、かつ同じく表９に示される目標全体層厚の硬質被覆層を蒸着することにより、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）１〜４をそれぞれ製造した。
【００３２】
また、比較の目的で、上記のドリル超硬基体の切刃に、ホーニングを施し、アセトン中で超音波洗浄し、乾燥した状態で、同じく図２に示される通常のアークイオンプレーティング装置に装入し、上記実施例１と同一の条件で、表１０に示される目標組成および目標層厚を有し、かつ層厚方向に沿って実質的に組成変化のない（Ｔｉ，Ａｌ，Ｃｒ）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）１〜４をそれぞれ製造した。
【００３３】
つぎに、上記本発明被覆超硬ドリル１〜４および従来被覆超硬ドリル１〜４のうち、本発明被覆超硬ドリル１および従来被覆超硬ドリル１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：０．３５ｍｍ／ｒｅｖ、
穴深さ：１２ｍｍ
の条件でのステンレス鋼の湿式高速高送り穴あけ切削加工試験、本発明被覆超硬ドリル２，３および従来被覆超硬ドリル２，３については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＦＣ２５０の板材、
切削速度：８０ｍ／ｍｉｎ．、
送り：０．５５ｍｍ／ｒｅｖ、
穴深さ：２４ｍｍ
の条件での鋳鉄の湿式高速高送り穴あけ切削加工試験、本発明被覆超硬ドリル４および従来被覆超硬ドリル４については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＦＣＤ４００の板材、
切削速度：９０ｍ／ｍｉｎ．、
送り：０．５５ｍｍ／ｒｅｖ、
穴深さ：５０ｍｍ
の条件でのダクタイル鋳鉄の湿式高速高送り穴あけ切削加工試験、をそれぞれ行い、いずれの湿式高速穴あけ切削加工試験（水溶性切削油使用）でも先端切刃面の逃げ面摩耗幅が０．３ｍｍに至るまでの穴あけ加工数を測定した。この測定結果を表９，１０にそれぞれ示した。
【００３４】
【表９】
【表１０】
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１〜８、本発明被覆超硬エンドミル１〜４、および本発明被覆超硬ドリル１〜４を構成する硬質被覆層におけるＡｌ成分最高含有点とＡｌ成分最低含有点の組成、並びに従来被覆超硬工具としての従来被覆超硬チップ１〜８、従来被覆超硬エンドミル１〜４、および従来被覆超硬ドリル１〜４の硬質被覆層の組成をオージェ分光分析装置を用いて測定したところ、それぞれ目標組成と実質的に同じ組成を示した。
また、これらの本発明被覆超硬工具の硬質被覆層におけるＡｌ成分最高含有点とＡｌ成分最低含有点間の間隔、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。
【００３７】
【発明の効果】
表３〜１０に示される結果から、硬質被覆層が層厚方向に、すぐれた高温硬さと耐熱性を有するＡｌ成分最高含有点と高強度と高靭性を有するＡｌ成分最低含有点とが交互に所定間隔をおいて繰り返し存在し、かつ前記Ａｌ成分最高含有点から前記Ａｌ成分最低含有点、前記Ａｌ成分最低含有点から前記Ａｌ成分最高含有点へＡｌ成分含有量が連続的に変化する成分濃度分布構造を有する本発明被覆超硬工具は、いずれも各種の鋼や鋳鉄などの高速切削加工を、高い機械的衝撃を伴う高切り込みや高送りなどの重切削条件で行なった場合にも、硬質被覆層がすぐれた耐チッピング性を発揮するのに対して、硬質被覆層が層厚方向に沿って実質的に組成変化のない（Ｔｉ，Ａｌ，Ｃｒ）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、強度および靭性に劣るものであるために、チッピングが発生し、これが原因で比較的短時間で使用寿命に至ることが明らかである。
上述のように、この発明の被覆超硬工具は、通常の条件での高速切削加工は勿論のこと、特に各種の鋼や鋳鉄などの高速切削加工を、高い機械的衝撃を伴う高切り込みや高送りなどの重切削条件で行なった場合にも、すぐれた耐チッピング性を発揮し、長期に亘ってすぐれた耐摩耗性を示すものであるから、切削加工の省力化および省エネ化、さらに低コスト化に十分満足に対応できるものである。
【図面の簡単な説明】
【図１】 この発明の被覆超硬工具を構成する硬質被覆層を形成するのに用いたアークイオンプレーティング装置を示し、（ａ）は概略平面図、（ｂ）は概略正面図である。
【図２】 従来被覆超硬工具を構成する硬質被覆層を形成するのに用いた通常のアークイオンプレーティング装置の概略説明図である。[0001]
BACKGROUND OF THE INVENTION
In this invention, the hard coating layer has high strength and high toughness, and is excellent in high-temperature hardness and heat resistance. Therefore, high-speed cutting such as various steels and cast irons is particularly suitable for high cutting and high mechanical impact. The present invention relates to a surface-coated cemented carbide cutting tool (hereinafter referred to as a coated cemented carbide tool) that exhibits excellent chipping resistance even when performed under heavy cutting conditions such as high feed.
[0002]
[Prior art]
In general, coated carbide tools are used for throwaway inserts that are detachably attached to the tip of a cutting tool for drilling and cutting of various materials such as steel and cast iron, and for flat cutting. There are drills, miniature drills, solid type end mills used for chamfering, grooving, shoulder processing, etc. Also, the throwaway tip is detachably attached and cutting is performed in the same way as the solid type end mill Throwaway end mill tools are known.
[0003]
Further, as a coated carbide tool, a substrate made of tungsten carbide (hereinafter referred to as WC) -based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) -based cermet (hereinafter collectively referred to as a cemented carbide substrate). ) On the surface of the composition formula: (Ti1-(X + Z)AlXCrZ) Ti, Al and Cr composite nitride satisfying N (wherein X represents 0.45 to 0.65, Z: 0.01 to 0.15 in atomic ratio) [hereinafter referred to as (Ti, Al , Cr) N], a coated carbide tool formed by physically vapor-depositing a hard coating layer composed of a layer with an average layer thickness of 1 to 15 μm is proposed, and the coated carbide tool constitutes the hard coating layer ( Ti, Al, Cr) N layer has excellent high-temperature properties (high-temperature hardness and heat resistance), so it can be used for high-speed continuous cutting and high-speed intermittent cutting of various steels and cast irons with high heat generation. Are known.
[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 a Ti—Al—Cr alloy having a predetermined composition is set, for example, at a current of 90 A, while being heated to a temperature of 500 ° C. At the same time, nitrogen gas is introduced into the apparatus as a reaction gas to form a reaction atmosphere of, for example, 2 Pa, while the cemented carbide substrate has a surface of the cemented carbide substrate under the condition that a bias voltage of, for example, −100 V is applied. In addition, it is also known to be produced by vapor-depositing a hard coating layer composed of the (Ti, Al, Cr) N layer.
[0005]
[Problems to be solved by the invention]
In recent years, the performance of cutting devices has been dramatically improved, but on the other hand, there is a strong demand for labor saving and energy saving and further cost reduction for cutting, and accordingly, cutting under heavy cutting conditions such as high cutting and high feed. However, there is a strong demand for coated carbide tools that exhibit excellent cutting performance, but the conventional coated carbide tools mentioned above have no problems when used under normal high-speed cutting conditions, When cutting is performed under heavy cutting conditions such as high cutting and high feed with high mechanical impact, chipping (microcracking) is likely to occur, especially due to insufficient strength and toughness of the hard coating layer. The current situation is that the service life is reached in a short time.
[0006]
[Means for Solving the Problems]
In view of the above, the present inventors have developed the above-mentioned conventional coated carbide tool in order to develop a coated carbide tool that exhibits excellent chipping resistance with a hard coating layer particularly in high-speed heavy cutting. As a result of conducting research with a focus on the hard coating layer,
(A) The (Ti, Al, Cr) 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 thickness. Arc ion plating apparatus having a structure as shown in FIG. 1 (a) and a schematic front view, for example. A rotating table for mounting a carbide substrate is provided in the center of the apparatus, and the Ti-Al-Cr alloy for forming the highest Al content point with a relatively high Al content is placed on one side with the rotating table in between, and Al is placed on the other side. Using an arc ion plating apparatus in which all Ti-Al-Cr alloys for forming the lowest content points are arranged facing each other as a cathode electrode (evaporation source), a plurality of carbide bases are arranged along the outer peripheral portion of the rotary table of the apparatus. In this state, the atmosphere inside the apparatus is changed to a nitrogen atmosphere, the rotary table is rotated, and the carbide substrate itself is rotated for the purpose of uniforming the thickness of the hard coating layer formed by vapor deposition. When an arc discharge is generated between the cathode electrode (evaporation source) and the anode electrode on both sides to form a (Ti, Al, Cr) N layer on the surface of the cemented carbide substrate, the resulting (Ti, In the Al, Cr) N layer, when the cemented carbide substrate arranged in a ring shape on the turntable is closest to the cathode electrode (evaporation source) of the Ti-Al-Cr alloy on one side, When the carbide substrate is closest to the cathode electrode of the Ti-Al-Cr alloy on the other side, the lowest Al component content point is formed in the layer. Table times In the layer, the Al component highest content point and the Al component lowest content point alternately appear at predetermined intervals along the layer thickness direction, and from the Al component highest content point, the Al component lowest content point, the Al lowest content point. It has a component concentration distribution structure in which the Al component content continuously changes from the content point to the Al content minimum content point.
[0007]
(B) In the (Ti, Al, Cr) N layer of the repeated continuous change component concentration distribution structure of (a) above, Al in the Ti—Al—Cr alloy which is the cathode electrode (evaporation source) on one side facing each other The Cr content corresponds to the Al and Cr content of the conventional Ti—Al—Cr alloy for forming a Ti (Al, Cr) N layer, and Ti— is the cathode electrode (evaporation source) on the other side. The Al content in the Al-Cr alloy is set to be relatively lower than the Al content in the conventional Ti-Al-Cr alloy, and the rotational speed of the turntable on which the carbide substrate is mounted is controlled. do it,
The above Al component highest content point is the composition formula: (Ti1- (X + Z)AlXCrZ) N (however, in atomic ratio, X is 0.45 to0.55, Z: 0.01 ~0.10),
The Al component minimum content point is the composition formula: (Ti1- (X + Z)AlXCrZ) N (however, in terms of atomic ratio, X represents 0.15 to 0.40, Z represents 0.01 to 0.15),
And the interval in the thickness direction of the adjacent Al component highest content point and Al component lowest content point adjacent to each other is 0.01 to 0.1 μm,
The Al 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 (Ti, Al, Cr) N layer, while the Al component minimum In the content point portion, since the Al content is lower and the Ti content is higher than the Al component highest content point portion, higher strength and toughness are secured, and these Al component highest content points and Al Since the interval between the minimum component content points is extremely small, it has a further excellent strength and toughness while maintaining excellent high-temperature characteristics as the characteristics of the entire layer. Coated carbide tools composed of Ti, Al, Cr) N layers, especially when high-speed cutting of various steels and cast iron is performed under heavy cutting conditions such as high cutting with high mechanical impact and high feed Also, it becomes to exhibit chipping resistance of the hard coating layer has excellent.
The research results shown in (a) and (b) above were obtained.
[0008]
The present invention has been made on the basis of the above research results. A hard coating layer composed of a (Ti, Al, Cr) N layer is physically applied on the surface of a cemented carbide substrate with an overall average layer thickness of 1 to 15 μm. In coated carbide tools formed by vapor deposition,
In the hard coating layer, the Al component highest content point and the Al component lowest content point are alternately present at predetermined intervals along the layer thickness direction, and the Al component lowest content from the Al component highest content point. Point, having a component concentration distribution structure in which the Al component content continuously changes from the Al component lowest content point to the Al component highest content point,
Furthermore, the highest Al component content point is the composition formula: (Ti1- (X + Z )AlXCrZ) N (however, in atomic ratio, X is 0.45 to0.55, Z: 0.01 ~0.10),
The Al component minimum content point is the composition formula: (Ti1- (X + Z)AlXCrZ) N (however, in terms of atomic ratio, X represents 0.15 to 0.40, Z represents 0.01 to 0.15),
And the interval between adjacent Al component highest content point and Al component lowest content point adjacent to each other is 0.01 to 0.1 μm.
This is characterized by a coated carbide tool that exhibits excellent chipping resistance under high-speed heavy cutting conditions.
[0009]
Next, in the coated carbide tool of the present invention, the reason why the structure of the hard coating layer constituting the tool is limited as described above will be described.
(A) Composition of the highest Al component content point
The Ti component in (Ti, Al, Cr) N at the highest Al component content point improves strength and toughness, the Al component improves high-temperature hardness and heat resistance (high-temperature characteristics), and Cr component further increases. It has the effect of improving heat resistance. Therefore, the higher the content ratio of Al and Cr components, the higher the high temperature characteristics and the more suitable for high speed cutting with high heat generation. The ratio (atomic ratio) of the X value shown to the total amount of Ti and Cr0.55And the Z value indicating the Cr content is the same.0.10Even if the Al content exceeds the above, even when the Al component minimum content point having high strength and high toughness is present adjacent to each other, a decrease in the strength and toughness of the layer itself is unavoidable, and as a result, chipping and the like are likely to occur. On the other hand, even if the X value is less than 0.45 and the Z value is less than 0.01, a desired improvement effect cannot be obtained in the high temperature characteristics.0.55, Z value 0.01 ~0.10It was determined.
[0010]
(B) Composition of Al component minimum content point
As described above, the Al component maximum content point is excellent in high temperature characteristics, but on the other hand, it is inferior in strength and toughness. Therefore, in order to compensate for the strength and toughness shortage of this Al component maximum content point, the Ti content ratio is High, while the Al content is low, thereby interposing in the thickness direction alternately Al component minimum content points that have high strength and high toughness, so that the X value indicating the proportion of Al is Ti and If the ratio (atomic ratio) in the total amount with the Cr component exceeds 0.40, the desired excellent strength and toughness cannot be secured, while if the X value is less than 0.15, the Al component Since the desired high-temperature characteristics cannot be provided at the lowest content point, the X value indicating the proportion of Al at the lowest content of the Al component was determined to be 0.15 to 0.40.
The Cr component at the Al component minimum content point is also contained for the purpose of improving heat resistance in the coexistence with the Al component and adapting to high-speed cutting with high heat generation as described above, and therefore the Z value is 0.01. If it is less than 1, the desired heat resistance improvement effect cannot be obtained. On the other hand, if the Z value exceeds 0.15, the strength and toughness at the Al component minimum content point tend to decrease, and it is difficult to improve the desired chipping resistance. Therefore, the Z value was determined to be 0.01 to 0.15.
[0011]
(C) Interval between the highest Al component content point and the lowest Al component content point
If the distance is less than 0.01 μm, it is difficult to clearly form each point with the above composition. As a result, the desired high-temperature characteristics, strength and toughness cannot be secured in the layer, and the distance is If the thickness exceeds 0.1 μm, the disadvantages of each point, that is, if the Al component is the highest content point, insufficient strength and toughness, and if the Al component is the lowest content point, insufficient high-temperature properties appear locally in the layer. Since the chipping easily occurs and the progress of wear is promoted, the interval is set to 0.01 to 0.1 μm.
[0012]
(D) Overall average layer thickness of the hard coating layer
If the layer thickness is less than 1 μm, the desired wear resistance cannot be ensured. On the other hand, if the average layer thickness exceeds 15 μm, chipping tends to occur. Therefore, the average layer thickness is 1 to 15 μm. Determined.
[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, TaC powder, NbC powder, and Co powder all having an average particle diameter of 1 to 3 μm are prepared, and these raw material powders are blended in the blending composition shown in Table 1, After wet mixing with a ball mill for 72 hours and drying, the green compact is press-molded into a green compact at a pressure of 100 MPa, and the green compact is sintered and sintered in a 6 Pa vacuum at a temperature of 1400 ° C. for 1 hour. After ligation, R: 0.03 honing is applied to the cutting edge, and a WC-base cemented carbide substrate with ISO standard / CNMG120408 chip shape is used.A-2 to A-4, A-6, and A-10Formed respectively.
[0014]
In addition, as raw material powder, TiCN (TiC / TiN = 50/50 by weight) powder having an average particle diameter of 0.5 to 2 μm, Mo2C powder, NbC powder, TaC powder, WC powder, Co powder, and Ni powder were prepared, and these raw material powders were blended in the blending composition shown in Table 2, wet-mixed with a ball mill for 24 hours, and dried. The green compact was press-molded at a pressure of 100 MPa, and the green compact was sintered in a nitrogen atmosphere of 2 kPa at a temperature of 1500 ° C. for 1 hour. After sintering, R = 0. Carbide substrate made of TiCN-based cermet with ISO-standard / CNMG120408 chip shape after honing of 03B-1, B-4, and B-6Formed respectively.
[0015]
Next, the above carbide substrateA-2 to A-4, A-6, and A-10, and B-1, B-4, and B-6Each of these was ultrasonically cleaned in acetone and dried, and mounted along the outer periphery on the rotary table in the arc ion plating apparatus shown in FIG. 1, and the cathode electrode (evaporation source) on one side As described above, the rotation table is composed of the Ti-Al-Cr alloy for forming the highest point of Al component having various component compositions and the Ti-Al-Cr alloy for forming the lowest point of Al component as the cathode electrode (evaporation source) on the other side. A bombard cleaning metal Ti is also mounted, and the inside of the apparatus is first heated to 500 ° C. with a heater while maintaining a vacuum of 0.5 Pa or less, and then the rotation A DC bias voltage of −1000 V is applied to a carbide substrate that rotates while rotating on the table, and a current of 100 A is passed between the metal Ti and the anode electrode of the cathode electrode. Is generated, and the surface of the carbide substrate is cleaned by Ti bombardment. Then, nitrogen gas is introduced into the apparatus as a reactive gas to form a reaction atmosphere of 2 Pa, and the super rotating body rotates while rotating on the rotary table. A DC bias voltage of −100 V is applied to the hard substrate, and each cathode electrode (the Ti-Al—Cr alloy for forming the highest Al component point and the Ti—Al—Cr alloy for forming the lowest Al component point) and anode An arc discharge is generated by passing a current of 100 A between the electrodes, so that the Al component maximum content point and the Al component minimum content of the target composition shown in Table 3 along the layer thickness direction are formed on the surface of the cemented carbide substrate. The points alternately and repeatedly exist at the target intervals shown in Table 3, and the Al component minimum content point from the Al component maximum content point, the Al component minimum content point By depositing a hard coating layer having a component concentration distribution structure in which the Al component content continuously changes to the highest Al component content point and also having a target total layer thickness shown in Table 3, the coated carbide of the present invention is deposited. Throw-away tip made of surface coated cemented carbide of the present invention as a tool (hereinafter referred to as coated carbide tip of the present invention)1-8Were manufactured respectively.
[0016]
Also, for comparison purposes, these carbide substratesA-2 to A-4, A-6, and A-10, and B-1, B-4, and B-6Were ultrasonically cleaned in acetone and dried, and charged into a normal arc ion plating apparatus shown in FIG. 2, respectively, and Ti—Al having various composition as a cathode electrode (evaporation source). -Cr alloy and bombard cleaning metal Ti are also mounted. First, the inside of the apparatus is heated to 500 ° C. with a heater while evacuating the apparatus and maintaining a vacuum of 0.5 Pa or less. A DC bias voltage of −1000 V is applied to the hard substrate, and a current of 100 A is passed between the metal Ti and the anode electrode of the cathode electrode to generate an arc discharge, whereby the surface of the carbide substrate is Ti bombard washed. Next, nitrogen gas is introduced into the apparatus as a reaction gas to make a reaction atmosphere of 2 Pa, and the bias voltage applied to the cemented carbide substrate is lowered to −100 V to To generate arc discharge between the electrode and the anode electrode, the respective surfaces of the cemented carbide substrate with Table4By depositing a hard coating layer composed of a (Ti, Al, Cr) N layer having a target composition and a target layer thickness shown in FIG. Conventional surface-coated cemented carbide throwaway tip as a hard tool (hereinafter referred to as conventional coated carbide tip)1-8Were manufactured respectively.
[0017]
Next, the coated carbide tip of the present invention described above1-8And conventional coated carbide tip1-8In the 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: 350 m / min. ,
Incision: 6mm,
Feed: 0.35 mm / rev. ,
Cutting time: 5 minutes
Wet continuous high-speed high-cut cutting test of stainless steel under the conditions of
Work material: JIS / S50C lengthwise equal 4 round bars with vertical grooves,
Cutting speed: 350 m / min. ,
Incision: 3mm,
Feed: 0.8 mm / rev. ,
Cutting time: 10 minutes,
Dry intermittent high-speed high-feed cutting test of carbon steel under the conditions of
Work material: JIS / SNCM439 round bar,
Cutting speed: 350 m / min. ,
Incision: 6mm,
Feed: 0.4 mm / rev. ,
Cutting time: 5 minutes
The dry continuous high-speed, high-cutting cutting test of the alloy steel under the above conditions was performed, and the flank wear width of the cutting edge was measured in any cutting test. This measurement result5It was shown to.
[0018]
[Table 1]
[Table 2]
[Table 3]
[Table 4]
[Table 5]
(Example 2)
As raw material powders, medium coarse WC powder having an average particle size of 5.5 μm, 0.8 μm fine WC powder, 1.3 μm TaC powder, 1.2 μm NbC powder, 2.3 μm CrThreeC2Prepared powder, 1.5 μm VC powder, 1.0 μm (Ti, W) C powder, and 1.8 μm Co powder.6Then, after adding wax, ball mill mixing in acetone for 24 hours, drying under reduced pressure, press-molding into various compacts of a predetermined shape at a pressure of 100 MPa, and these compacts Is heated to a predetermined temperature within a range of 1370 to 1470 ° C. at a heating rate of 7 ° C./min in a 6 Pa vacuum atmosphere, held at this temperature for 1 hour, and then sintered under furnace cooling conditions. Three types of sintered rods for forming a carbide substrate having diameters of 8 mm, 13 mm, and 26 mmC-1, C-2, C-4, C-5, and C-7 are formed, and among the above-mentioned three kinds of round bar sintered bodies, round bar sintered bodies C-1, C-2 , C-5, and C-7In the grinding process,6In the combination shown in Fig. 4, the diameter x length of the cutting edge part was 6 mm x 13 mm, 10 mm x 22 mm, and 20 mm x 45 mm, respectively, and each had a four-blade square shape with a twist angle of 30 degrees.End mill carbide substrateWere manufactured respectively.
[0024]
Then theseEnd mill carbide substrateWas ultrasonically cleaned in acetone and dried, and then charged into the arc ion plating apparatus shown in FIG. 1 and expressed along the layer thickness direction under the same conditions as in Example 1 above.7The Al component maximum content point and the Al component minimum content point of the target composition shown in the table are alternately displayed.7A component that is repeatedly present at the target interval shown in FIG. 5 and has an Al component content continuously changing from the highest Al component content point to the lowest Al component content point and from the lowest Al component content point to the highest Al component content point. Concentration distribution structure and table7The surface-coated cemented carbide end mill 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)1-4Were manufactured respectively.
[0025]
For comparison purposes, the aboveEnd mill carbide substrateWas ultrasonically washed in acetone and dried, and charged into a normal arc ion plating apparatus shown in FIG. 2 under the same conditions as in Example 1 above.8By depositing a hard coating layer composed of a (Ti, Al, Cr) N layer having a target composition and a target layer thickness shown in FIG. Conventional surface-coated cemented carbide end mill as a hard tool (hereinafter referred to as conventional coated carbide end mill)1-4Were manufactured respectively.
[0026]
Next, the present invention coated carbide end mill1-4And conventional coated carbide end mill1-4Of these, the coated carbide end mill of the present invention1, 2And conventional coated carbide end mill1, 2about,
Work material: Plane dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SKD61 plate material,
Cutting speed: 120 m / min. ,
Groove depth (cut): 9 mm,
Table feed: 1400mm / min,
Tool steel dry high-speed high-grooving groove cutting test under the conditions of the present invention, coated carbide end mill of the present invention3And conventional coated carbide end mill3about,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / SUS304 plate,
Cutting speed: 120 m / min. ,
Groove depth (cut): 15 mm
Table feed: 830 mm / min,
Stainless steel dry type high-speed, high-grooving groove cutting test, coated carbide end mill of the present invention4And conventional coated carbide end mill4about,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / SCM440 plate material,
Cutting speed: 150 m / min. ,
Groove depth (cut): 10 mm,
Table feed: 540 mm / min,
In each of the groove cutting tests, the flank wear width of the outer peripheral edge of the cutting edge reaches 0.1 mm, which is a guide for the service life. The cutting groove length up to was measured. This measurement result7,8Respectively.
[0027]
[Table 6]
[Table 7]
[Table 8]
(Example 3)
The diameter produced in Example 2 above isOf the three types of round bar sintered bodies of 8 mm, 13 mm, and 26 mm, round bar sintered bodies C-2, C-4, C-5, and C-7 were used, and grinding was performed. In processing, the combinations shown in Table 6The diameters and lengths of the groove forming portions are 4 mm × 13 mm, 8 mm × 22 mm, and 16 mm × 45 mm, respectively, and each has a two-blade shape with a twist angle of 30 degrees.Drilled carbide substrateWere manufactured respectively.
[0031]
Then theseDrilled carbide substrateThe cutting blade is subjected to honing, ultrasonically cleaned in acetone, and in a dried state, the arc blade is inserted into the arc ion plating apparatus shown in FIG. Table along direction9The Al component maximum content point and the Al component minimum content point of the target composition shown in the table are alternately displayed.9A component that is repeatedly present at the target interval shown in FIG. 5 and has an Al component content continuously changing from the highest Al component content point to the lowest Al component content point and from the lowest Al component content point to the highest Al component content point. Concentration distribution structure and table9The surface-coated cemented carbide drill of the present invention as the coated carbide tool of the present invention (hereinafter referred to as the coated carbide drill of the present invention)1-4Were manufactured respectively.
[0032]
For comparison purposes, the aboveDrilled carbide substrateThe cutting blade is subjected to honing, ultrasonically cleaned in acetone, and in a dry state, it is inserted into a normal arc ion plating apparatus shown in FIG. 2 under the same conditions as in Example 1 above. table10By depositing a hard coating layer composed of a (Ti, Al, Cr) N layer having a target composition and a target layer thickness shown in FIG. Conventional surface-coated cemented carbide drill as a hard tool (hereinafter referred to as conventional coated carbide drill)1-4Were manufactured respectively.
[0033]
Next, the coated carbide drill of the present invention1-4And conventional coated carbide drill1-4Of these, the coated carbide drill of the present invention1And conventional coated carbide drill1about,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / SUS304 plate,
Cutting speed: 60 m / min. ,
Feed: 0.35mm / rev,
Hole depth: 12mm
Stainless steel wet high-speed high-feed drilling test, coated carbide drill of the present invention2, 3And conventional coated carbide drill2, 3about,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / FC250 plate material,
Cutting speed: 80 m / min. ,
Feed: 0.55mm / rev,
Hole depth: 24mm
Cast iron wet high speed high feed drilling test under the conditions of the present invention, coated carbide drill of the present invention4And conventional coated carbide drill4about,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / FCD400 plate material,
Cutting speed: 90 m / min. ,
Feed: 0.55mm / rev,
Hole depth: 50mm
We performed a high-speed, high-feed, high-feed drilling test of ductile cast iron under the above conditions, and the flank wear width of the cutting edge surface was 0.3 mm in any wet high-speed drilling test (using water-soluble cutting oil) The number of drilling processes was measured. This measurement result9, 10Respectively.
[0034]
[Table 9]
[Table 10]
The present invention coated carbide tip as the present coated carbide tool obtained as a result1-8The coated carbide end mill of the present invention1-4, And the coated carbide drill of the present invention1-4Composition of Al component maximum content point and Al component minimum content point in the hard coating layer constituting the material, and the conventional coated carbide tip as a conventional coated carbide tool1-8Conventional coated carbide end mill1-4, And conventional coated carbide drill1-4When 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 Al component content point and the lowest Al component content point in the hard coating layer of the coated carbide tool of the present invention, and 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.
[0037]
【The invention's effect】
table3-10From the results shown in Fig. 4, the hard coating layer has an Al component maximum content point having excellent high temperature hardness and heat resistance and an Al component minimum content point having high strength and toughness alternately in the thickness direction at predetermined intervals. And a component concentration distribution structure in which the Al component content continuously changes from the Al component highest content point to the Al component lowest content point and from the Al component lowest content point to the Al component highest content point. The coated carbide tool of the present invention has an excellent hard coating layer even when high-speed cutting of various types of steel and cast iron is performed under heavy cutting conditions such as high cutting with high mechanical impact and high feed. In the conventional coated carbide tool composed of a (Ti, Al, Cr) N layer in which the hard coating layer has substantially no composition change along the thickness direction, the hard coating layer exhibits the above-mentioned chipping resistance. Excellent coating layer Although having a high-temperature hardness and heat resistance, because it is inferior in strength and toughness, chipping occurs and this is apparent that lead to a relatively short time service life due.
As described above, the coated carbide tool of the present invention is not only used for high-speed cutting under normal conditions, but particularly for high-speed cutting such as various types of steel and cast iron. Even when performed under heavy cutting conditions such as feeding, it exhibits excellent chipping resistance and excellent wear resistance over a long period of time. It is possible to respond satisfactorily to conversion.
[Brief description of the drawings]
FIG. 1 shows an arc ion plating apparatus used to form a hard coating layer constituting a coated carbide tool of the present invention, wherein (a) is a schematic plan view and (b) is a schematic front view.
FIG. 2 is a schematic explanatory view of a normal arc ion plating apparatus used to form a hard coating layer constituting a conventional coated carbide tool.
Claims (1)
上記硬質被覆層が、層厚方向にそって、Ａｌ成分最高含有点とＡｌ成分最低含有点とが所定間隔をおいて交互に繰り返し存在し、かつ前記Ａｌ成分最高含有点から前記Ａｌ成分最低含有点、前記Ａｌ成分最低含有点から前記Ａｌ成分最高含有点へＡｌ成分含有量が連続的に変化する成分濃度分布構造を有し、
さらに、上記Ａｌ成分最高含有点が、組成式：（Ｔｉ1-(X+Z)ＡｌX ＣｒZ）Ｎ（ただし、原子比で、Ｘは０．４５〜０．５５、Ｚ：０．０１〜０．１０を示す）、
上記Ａｌ成分最低含有点が、組成式：（Ｔｉ1-(X+Z)ＡｌX ＣｒZ）Ｎ（ただし、原子比で、Ｘは０．１５〜０．４０、Ｚ：０．０１〜０．１５を示す）、
をそれぞれ満足し、かつ隣り合う上記Ａｌ成分最高含有点とＡｌ成分最低含有点の間隔が、０．０１〜０．１μmであること、
を特徴とする高速重切削条件で硬質被覆層がすぐれた耐チッピング性を発揮する表面被覆超硬合金製切削工具。 A turning table for mounting either or both of a tungsten carbide base cemented carbide substrate and a titanium carbonitride-based cermet substrate is provided at the center of the apparatus, and Ti for forming the highest Al component content is placed on one side of the rotating table. -An arc ion plating apparatus in which an Al-Cr alloy and a Ti-Al-Cr alloy for forming an Al component minimum content point on the other side are arranged to face each other as a cathode electrode (evaporation source), and the outer peripheral portion of the rotary table of this apparatus A plurality of the bases are mounted in a ring shape along with the cathode electrodes (evaporation sources) on both sides while rotating the rotary table with the atmosphere inside the apparatus being a nitrogen atmosphere and rotating the base itself. and by generating arc discharge between the anode electrode, the surface of the substrate, the hard coating layer made of a composite nitride of Ti, Al and Cr In the overall average layer surface-coated cemented carbide cutting tool comprising depositing a thickness of 15 m,
In the hard coating layer, the Al component maximum content point and the Al component minimum content point are alternately present at predetermined intervals along the layer thickness direction, and the Al component minimum content is from the Al component maximum content point. Point, having a component concentration distribution structure in which the Al component content continuously changes from the Al component lowest content point to the Al component highest content point,
Further, the highest Al component content point is the composition formula: (Ti 1- (X + Z) Al x Cr z ) N (wherein the atomic ratio, X is 0.45 to 0.55 , Z: 0.01 ~ Indicates 0.10 ),
The Al component minimum content point, composition formula: (Ti 1- (X + Z ) Al X Cr Z) N ( provided that an atomic ratio, X is 0.15 to 0.40, Z: from 0.01 to 0 .15)
And the interval between the Al component highest content point and the Al component lowest content point adjacent to each other is 0.01 to 0.1 μm,
A surface-coated cemented carbide cutting tool that exhibits excellent chipping resistance under high-speed heavy cutting conditions.
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| JP2002151755A JP4029323B2 (en) | 2002-05-27 | 2002-05-27 | Surface coated cemented carbide cutting tool with excellent chipping resistance with hard coating layer under high speed heavy cutting conditions |
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| JP2002151755A JP4029323B2 (en) | 2002-05-27 | 2002-05-27 | Surface coated cemented carbide cutting tool with excellent chipping resistance with hard coating layer under high speed heavy cutting conditions |
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| JP2003340607A JP2003340607A (en) | 2003-12-02 |
| JP4029323B2 true JP4029323B2 (en) | 2008-01-09 |
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| DE59106090D1 (en) * | 1991-01-21 | 1995-08-31 | Balzers Hochvakuum | Coated, highly wear-resistant tool and physical coating process for coating highly wear-resistant tools. |
| JP2979921B2 (en) * | 1993-09-30 | 1999-11-22 | 住友電気工業株式会社 | Ultra thin film laminate |
| JP3382781B2 (en) * | 1996-06-05 | 2003-03-04 | 日立ツール株式会社 | Multi-layer coated hard tool |
| JPH11216601A (en) * | 1998-02-04 | 1999-08-10 | Osg Corp | Coating tool with hard laminate film |
| JP3928480B2 (en) * | 2002-05-27 | 2007-06-13 | 三菱マテリアル株式会社 | Surface coated cemented carbide cutting tool with excellent wear resistance with hard coating layer in high speed cutting |
| JP3928481B2 (en) * | 2002-05-27 | 2007-06-13 | 三菱マテリアル株式会社 | Surface-coated cemented carbide cutting tool with excellent wear resistance under high-speed heavy cutting conditions. |
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