JP3928497B2

JP3928497B2 - Surface coated cemented carbide cutting tool with excellent chipping resistance with hard coating layer under high speed heavy cutting conditions

Info

Publication number: JP3928497B2
Application number: JP2002183768A
Authority: JP
Inventors: 秀充高岡; 惠滋中村
Original assignee: Mitsubishi Materials Corp
Current assignee: Mitsubishi Materials Corp
Priority date: 2002-06-25
Filing date: 2002-06-25
Publication date: 2007-06-13
Anticipated expiration: 2022-06-25
Also published as: JP2005230916A

Description

【０００１】
【発明の属する技術分野】
この発明は、硬質被覆層が一段とすぐれた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：（Ｔｉ_1-(X+Y)Ａｌ_XＺｒ_Y）Ｎ（ただし、原子比で、Ｘは０．４５〜０．６５、Ｙ：０．０１〜０．１５を示す）を満足するＴｉとＡｌとＺｒの複合窒化物［以下、（Ｔｉ，Ａｌ，Ｚｒ）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，Ｚｒ）Ｎ層がすぐれた高温特性（高温硬さおよび耐熱性、さらに高温強度）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４００℃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−Ｚｒ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−２００Ｖ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，Ｚｒ）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，Ｚｒ）Ｎ層は、厚さ全体に亘って実質的に均一な組成を有し、したがって均質な性質を有するが、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、一方側に上記の従来（Ｔｉ，Ａｌ，Ｚｒ）Ｎ層の形成にカソード電極（蒸発源）として用いられたＴｉ−Ａｌ−Ｚｒ合金に相当するＴｉ−Ａｌ−Ｚｒ合金、他方側に前記Ｔｉ−Ａｌ−Ｚｒに比して相対的にＡｌ含有量の低いＴｉ−Ａｌ−Ｚｒ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，Ｚｒ）Ｎ層を形成すると、この結果の（Ｔｉ，Ａｌ，Ｚｒ）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−Ｚｒ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相対的にＡｌ含有量の低いＴｉ−Ａｌ−Ｚｒ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厚さ方向にそって前記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，Ｚｒ）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−Ｚｒ合金におけるＡｌおよびＺｒ含有量を上記の従来（Ｔｉ，Ａｌ，Ｚｒ）Ｎ層形成用Ｔｉ−Ａｌ−Ｚｒ合金のＡｌおよびＺｒ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−Ｚｒ合金におけるＡｌ含有量を上記の従来Ｔｉ−Ａｌ−Ｚｒ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：（Ｔｉ_1-(X+Y)Ａｌ_XＺｒ_Y）Ｎ（ただし、原子比で、Ｘは０．４５〜０．６５、Ｙ：０．０１〜０．１５を示す）、
上記Ａｌ成分最低含有点が、組成式：（Ｔｉ_1-(X+Y)Ａｌ_XＺｒ_Y）Ｎ（ただし、原子比で、Ｘは０．１５〜０．３０、Ｙ：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，Ｚｒ）Ｎ層の具備する高温硬さおよび耐熱性、強度および靭性、さらに高温強度に相当する性質を有し、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、相対的に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るようになり、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硬さと耐熱性、さらに高温強度を保持した状態で一段とすぐれた強度および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，Ｚｒ）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、装置中央部に超硬基体装着用回転テーブルを設け、前記回転テーブルを挟んで、一方側にＡｌ成分最高含有点形成用Ｔｉ−Ａｌ−Ｚｒ合金、他方側にＡｌ成分最低含有点形成用Ｔｉ−Ａｌ−Ｚｒ合金をカソード電極（蒸発源）として対向配置したアークイオンプレーティング装置を用い、この装置の前記回転テーブルの外周部に沿って複数の超硬基体をリング状に装着し、この状態で装置内雰囲気を窒素雰囲気として前記回転テーブルを回転させると共に、超硬基体自体も自転させながら、前記の両側のカソード電極（蒸発源）とアノード電極との間にアーク放電を発生させて、超硬基体の表面に、（Ｔｉ，Ａｌ，Ｚｒ）Ｎ層からなる硬質被覆層を１〜１５μｍの全体平均層厚で蒸着してなる被覆超硬工具にして、
上記硬質被覆層が、層厚方向にそって、Ａｌ成分最高含有点とＡｌ成分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：（Ｔｉ_1-(X+Y)Ａｌ_XＺｒ_Y）Ｎ（ただし、原子比で、Ｘは０．４５〜０．６５、Ｙ：０．０１〜０．１５を示す）、
上記Ａｌ成分最低含有点が、組成式：（Ｔｉ_1-(X+Y)Ａｌ_XＺｒ_Y）Ｎ（ただし、原子比で、Ｘは０．１５〜０．３０、Ｙ：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，Ｚｒ）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を向上させる作用があり、したがってＡｌ成分の含有割合が高くなればなるほど高温硬さおよび耐熱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Ｚｒの合量に占める割合（原子比）で０．６５を越えると、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は避けられず、この結果チッピングなどが発生し易くなり、一方同Ｘ値が同０．４５未満になると、所定の高温硬さおよび耐熱性を確保することが困難になることから、Ｘ値を０．４５〜０．６５と定めた。
さらに、Ｚｒ成分には高温強度を向上させる作用があるが、Ｚｒの割合を示すＹ値がＡｌとＴｉの合量に占める割合（原子比）で０．０１未満では所望の高温強度向上効果が得られず、さらに同Ｙ値が０．１５を超えると、高温硬さおよび耐熱性に低下傾向が現れるようになることから、Ｙ値を０．０１〜０．１５とそれぞれ定めた。
【００１０】
（ｂ）Ａｌ成分最低含有点の組成
上記の通りＡｌ成分最高含有点は所定の高温硬さおよび耐熱性、さらに高温強度を有するが、反面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の高速切削加工では強度および靭性不足は避けられず、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、これによって一段とすぐれた強度と靭性を有する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Ｚｒ成分との合量に占める割合（原子比）で０．３０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、所定の高温硬さおよび耐熱性を確保することができず、これが原因で高温硬さおよび耐熱性のすぐれたＡｌ成分最高含有点が隣接して存在しても層自体の摩耗進行が促進するようになることから、Ａｌ成分最低含有点でのＡｌの割合を示すＸ値を０．１５〜０．３０と定めた。
さらに、Ａｌ成分最低含有点におけるＺｒ成分も、上記の通り高温強度を向上させ、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Ｙ値が０．０１未満では所望の高温強度向上効果が得られず、一方Ｙ値が０．１５を越えると高温硬さおよび耐熱性に低下傾向が現れるようになり、摩耗進行の原因となることから、Ｙ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、この結果層に所定の高温硬さと耐熱性、および高温強度を確保した上で、さらに一段とすぐれた強度と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を越えると重切削条件での高速切削加工で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硬さおよび耐熱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、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４８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：１４２０℃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・ＣＮＭＧ１２０４１２のチップ形状をもったＷＣ基超硬合金製のチップ超硬基体Ａ−１〜Ａ−５，Ａ−８〜１０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２ｋＰａの窒素雰囲気中、温度：１５２０℃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・ＣＮＭＧ１２０４１２のチップ形状をもったＴｉＣＮ系サーメット製のチップ超硬基体Ｂ−２〜Ｂ−５を形成した。
【００１５】
ついで、上記のチップ超硬基体Ａ−１〜Ａ−５，Ａ−８〜１０およびＢ−２〜Ｂ−５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−Ｚｒ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−Ｚｒ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３Ｐａ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−３０Ｖ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−Ｚｒ合金およびＡｌ成分最低含有点形成用Ｔｉ−Ａｌ−Ｚｒ合金)とアノード電極との間に１５０Ａ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、厚さ方向に沿って表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）１〜１２をそれぞれ製造した。
【００１６】
また、比較の目的で、これらチップ超硬基体Ａ−１〜Ａ−５，Ａ−８〜１０およびＢ−２〜Ｂ−５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−Ｚｒ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４００℃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９０Ａ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−２００Ｖ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、かつ厚さ方向に沿って実質的に組成変化のない（Ｔｉ，Ａｌ，Ｚｒ）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）１〜１２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１〜１２および従来被覆超硬チップ１〜１２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・ＳＮＣＭ４３９の丸棒、
切削速度：３００ｍ／ｍｉｎ．、
切り込み：５．５ｍｍ、
送り：０．１５ｍｍ／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、
被削材：ＪＩＳ・ＳＣＭ４４０の長さ方向等間隔４本縦溝入り丸棒、
切削速度：３００ｍ／ｍｉｎ．、
切り込み：１．６ｍｍ、
送り：０．５ｍｍ／ｒｅｖ．、
切削時間：５分、
の条件での合金鋼の乾式断続高速高送り切削加工試験、さらに、
被削材：ＪＩＳ・ＦＣ３００の丸棒、
切削速度：３２０ｍ／ｍｉｎ．、
切り込み：５．５ｍｍ、
送り：０．１５ｍ／ｒｅｖ．、
切削時間：５分、
の条件での鋳鉄の乾式連続高速高切り込み切削加工試験を行い、いずれの切削加
工試験でも切刃の逃げ面摩耗幅を測定した。この測定結果を表５に示した。
【００１８】
【表１】

【００１９】
【表２】

【００２０】
【表３】

【００２１】
【表４】

【００２２】
【表５】

【００２３】
（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５０時間ボールミル混合し、減圧乾燥した後、１００ＭＰａの圧力で所定形状の各種の圧粉体にプレス成形し、これらの圧粉体を、６Ｐａの真空雰囲気中、７℃／分の昇温速度で１３７０〜１４７０℃の範囲内の所定の温度に昇温し、この温度に１時間保持後、炉冷の条件で焼結して、直径が８ｍｍ、１３ｍｍ、および２６ｍｍの３種の超硬基体形成用丸棒焼結体Ｃ−１〜Ｃ−８を形成し、さらに前記の３種の丸棒焼結体のうちの丸棒焼結体Ｃ−１，Ｃ−２，Ｃ−４，Ｃ−５，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）１〜５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、かつ厚さ方向に沿って実質的に組成変化のない（Ｔｉ，Ａｌ，Ｚｒ）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）１〜５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１〜５および従来被覆超硬エンドミル１〜５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・ＦＣ３００の板材、
切削速度：３２０ｍ／ｍｉｎ．、
軸方向切り込み：１０ｍｍ、
径方向切り込み：１．８ｍｍ、
テーブル送り：２１０ｍｍ／分、
の条件での鋳鉄の湿式高速高切り込み側面切削加工試験、本発明被覆超硬エンドミル３，４および従来被覆超硬エンドミル３，４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：３００ｍ／ｍｉｎ．、
軸方向切り込み：１８ｍｍ、
径方向切り込み：３ｍｍ、
テーブル送り：１９５ｍｍ／分、
の条件での合金鋼の湿式高速高切り込み側面切削加工試験、本発明被覆超硬エンドミル５および従来被覆超硬エンドミル５については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＳＮＣＭ４３９の板材、
切削速度：２９０ｍ／ｍｉｎ．、
軸方向切り込み：４０ｍｍ、
径方向切り込み：６ｍｍ、
テーブル送り：１００ｍｍ／分、
の条件での合金鋼の湿式高速高切り込み側面切削加工試験をそれぞれ行い、いずれの湿式側面切削加工試験（水溶性切削油使用）でも切刃部の外周刃の逃げ面摩耗幅が使用寿命の目安とされる０．１ｍｍに至るまでの切削長を測定した。この測定結果を表７，８にそれぞれ示した。
【００２７】
【表６】

【００２８】
【表７】

【００２９】
【表８】

【００３０】
（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Ｃ−１〜Ｃ−８のうちの丸棒焼結体Ｃ−２，Ｃ−３，Ｃ−５〜Ｃ−８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）１〜６をそれぞれ製造した。
【００３２】
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１０に示される目標組成および目標層厚を有し、かつ厚さ方向に沿って実質的に組成変化のない（Ｔｉ，Ａｌ，Ｚｒ）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）１〜６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１〜６および従来被覆超硬ドリル１〜６のうち、本発明被覆超硬ドリル１，２および従来被覆超硬ドリル１，２については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＦＣ３００の板材、
切削速度：２００ｍ／ｍｉｎ．、
送り：０．５ｍｍ／ｒｅｖ、
穴深さ：１０ｍｍ
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３，４および従来被覆超硬ドリル３，４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：１７５ｍ／ｍｉｎ．、
送り：０．４ｍｍ／ｒｅｖ、
穴深さ：１．５ｍｍ
の条件での合金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５，６および従来被覆超硬ドリル５，６については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＳＮＣＭ４３９の板材、
切削速度：１７５ｍ／ｍｉｎ．、
送り：０．５ｍｍ／ｒｅｖ、
穴深さ：３０ｍｍ
の条件での合金鋼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】

【００３５】
【表１０】

【００３６】
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１〜１２、本発明被覆超硬エンドミル１〜５、および本発明被覆超硬ドリル１〜６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１〜１２、従来被覆超硬エンドミル１〜５、および従来被覆超硬ドリル１〜６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、硬質被覆層が厚さ方向に、所定の高温硬さと耐熱性、さらに高温強度を有するＡｌ成分最高含有点と相対的に一段とすぐれた強度と靭性を有する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、硬質被覆層が厚さ方向に沿って実質的に組成変化のない（Ｔｉ，Ａｌ，Ｚｒ）Ｎ層からなる従来被覆超硬工具においては、重切削条件での高速切削加工では前記硬質被覆層の強度および靭性不足が原因で、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
This invention has a high strength and high toughness with a hard coating layer that is further superior, and is also excellent in high temperature hardness and heat resistance. Therefore, high-speed cutting such as various steels and cast irons is particularly accompanied by high mechanical impact. The present invention relates to a surface-coated cemented carbide cutting tool (hereinafter referred to as coated carbide tool) that exhibits excellent chipping resistance even when performed under heavy cutting conditions such as high cutting and 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 carbide substrate). ) On the surface of the composition formula: (Ti _{1- (X + Y)} Al _X Zr _Y ) N (wherein, X is 0.45 to 0.65, Y: 0.01 to 0.15 in atomic ratio) A hard coating layer composed of a composite nitride of Ti, Al, and Zr satisfying (shown below) [hereinafter referred to as (Ti, Al, Zr) N] layer is physically deposited with an average layer thickness of 1 to 15 μm. Hard tools have been proposed, and such coated carbide tools have excellent high-temperature properties (high-temperature hardness and heat resistance, and high-temperature strength) in which the (Ti, Al, Zr) N layer constituting the hard coating layer is excellent. , High-speed continuous cutting and high-speed intermittent cutting of various types of steel and cast iron with high heat generation It is also known to be used in the factory.
[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—Zr alloy having a predetermined composition is set, for example, at a current of 90 A, while being heated to a temperature of 400 ° 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. On the other hand, the surface of the cemented carbide substrate is applied to the cemented carbide substrate with a bias voltage of, for example, −200 V applied. In addition, it is also known to be produced by vapor-depositing a hard coating layer composed of the (Ti, Al, Zr) 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, focusing on the hard coating layer
(A) The (Ti, Al, Zr) 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. For example, an arc ion plating apparatus having a structure shown in a schematic plan view in FIG. 1A and a schematic front view in FIG. Ti-Al-Zr used as a cathode electrode (evaporation source) for forming the conventional (Ti, Al, Zr) N layer on one side with a turntable for mounting a carbide substrate. Ti-Al-Zr alloy corresponding to the alloy and Ti-Al-Zr alloy having a relatively low Al content compared to the Ti-Al-Zr on the other side are both arranged as a cathode electrode (evaporation source). Arc ion lamp Using a coating device, a plurality of cemented carbide substrates are attached in a ring shape along the outer periphery of the rotary table of this device. In this state, the rotary table is rotated with the atmosphere inside the device being a nitrogen atmosphere, and vapor deposition is performed. In order to make the thickness of the hard coating layer uniform, the carbide substrate itself is rotated, while arc discharge is generated between the cathode electrode (evaporation source) and the anode electrode on both sides, thereby the carbide substrate. When the (Ti, Al, Zr) N layer is formed on the surface of the substrate, in the resulting (Ti, Al, Zr) N layer, the cemented carbide substrate arranged in a ring shape on the rotary table has the one side described above. When the Ti-Al-Zr alloy cathode electrode (evaporation source) is closest, the highest Al content point is formed in the layer, and the cemented carbide substrate has a relatively Al content on the other side. Low Ti-A -When the Zr alloy is closest to the cathode electrode, the Al component minimum content point is formed in the layer, and the rotation of the rotary table causes the Al component maximum content point and the Al component minimum content along the thickness direction in the layer. A component in which the content point continuously and repeatedly appears at a predetermined interval, and the Al content continuously changes from the Al content highest content point to the Al content lowest content point, from the Al minimum content point to the Al content lowest content point Have a concentration distribution structure.
[0007]
(B) In the (Ti, Al, Zr) N layer having the repeated continuous change component concentration distribution structure of (a) above, Al and Ti in the Ti—Al—Zr alloy which is the cathode electrode (evaporation source) on one side facing each other The Zr content is equivalent to the Al and Zr contents of the above-mentioned conventional (Ti, Al, Zr) N layer forming Ti-Al-Zr alloy, and Ti-- which is the cathode electrode (evaporation source) on the other side The Al content in the Al-Zr alloy is set to be relatively lower than the Al content in the conventional Ti-Al-Zr alloy, and the rotational speed of the turntable on which the carbide substrate is mounted is controlled. do it,
The highest Al component content point is the composition formula: (Ti _{1- (X + Y)} Al _X Zr _Y ) N (however, in atomic ratio, X is 0.45 to 0.65, Y: 0.01 to 0) .15)
The Al component minimum content point, composition _{formula: (Ti 1- (X + Y} ) Al X Zr Y) N ( provided that an atomic ratio, X is 0.15 to 0.30, Y: .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 has properties corresponding to the high temperature hardness and heat resistance, strength and toughness of the conventional (Ti, Al, Zr) N layer, and high temperature strength. In the lowest content point portion, the Al content is lower than the highest Al content point portion, and the Ti content is relatively high, so that higher strength and toughness can be secured, and Since the distance between the highest Al component content point and the lowest Al component content point has been made extremely small, it has excellent high-temperature hardness and heat resistance as characteristics of the entire layer, and further improved strength and toughness while maintaining high-temperature strength. Therefore, a coated carbide tool composed of a (Ti, Al, Zr) N layer with a hard coating layer is particularly suitable for high-speed cutting such as various steels and cast iron. Also, it becomes to exhibit chipping resistance of the hard coating layer has excellent case of performing heavy cutting conditions such as high cut and high feed with.
The research results shown in (a) and (b) above were obtained.
[0008]
The present invention has been made based on the above research results, and is provided with a carbide substrate mounting rotary table at the center of the apparatus, sandwiching the rotary table, and having Al component highest content point forming Ti on one side. -An arc ion plating apparatus in which an Al-Zr alloy and a Ti-Al-Zr 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 cemented carbide substrates are attached in a ring shape along with the cathode electrode (evaporation) on the both sides while rotating the rotary table with the atmosphere inside the apparatus being a nitrogen atmosphere and rotating the cemented carbide substrate itself. source) and by generating arc discharge between the anode electrode, the surface of the carbide substrate, (Ti, Al, Zr) total average layer thickness of 1~15μm the hard coating layer consisting of N layers In the deposited comprising coated cemented carbide tool,
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,
Furthermore, the Al component maximum content point, composition _{formula: (Ti 1- (X + Y} ) Al X Zr Y) N ( provided that an atomic ratio, X is 0.45 to 0.65, Y: 0.01 ~ 0.15)
The Al component minimum content point, composition _{formula: (Ti 1- (X + Y} ) Al X Zr Y) N ( provided that an atomic ratio, X is 0.15 to 0.30, Y: .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 Al component highest content point Ti component in (Ti, Al, Zr) N of Al component highest content point improves strength and toughness, and the Al component improves high temperature hardness and heat resistance. Therefore, the higher the content ratio of the Al component, the higher the high-temperature hardness and heat resistance, and the more suitable for high-speed cutting with high heat generation, the X value indicating the Al content ratio If the ratio (atomic ratio) of Ti to Zr exceeds 0.65, the strength and toughness of the layer itself will decrease even if the Al component minimum content point having high strength and high toughness is present adjacently. As a result, chipping or the like is likely to occur. On the other hand, if the X value is less than 0.45, it is difficult to ensure the predetermined high-temperature hardness and heat resistance. 0.45 to 0.65 It was determined.
Further, the Zr component has an effect of improving the high temperature strength, but if the Y value indicating the ratio of Zr is less than 0.01 in the ratio (atomic ratio) to the total amount of Al and Ti, the desired high temperature strength improving effect is obtained. If the Y value exceeds 0.15, the Y value is determined to be 0.01 to 0.15, since the high temperature hardness and the heat resistance tend to decrease.
[0010]
(B) Composition of Al component minimum content point As described above, the Al component maximum content point has a predetermined high-temperature hardness and heat resistance and high-temperature strength, but on the other hand, it has a high mechanical impact, such as high cutting and high feed. Insufficient strength and toughness are unavoidable in high-speed cutting under cutting conditions, and in order to make up for the lack of strength and toughness at the highest Al content point, the Ti content is high, while the Al content is low. The minimum content of Al component having high strength and toughness is alternately interposed in the thickness direction, and therefore, the X value indicating the proportion of Al is 0 in terms of the total amount of Ti and Zr components (atomic ratio). If it exceeds .30 , the desired excellent strength and toughness cannot be ensured. On the other hand, if the X value is less than 0.15, the predetermined high temperature hardness and heat resistance cannot be ensured. As a result, the wear progress of the layer itself is promoted even if the Al component highest content point with excellent high-temperature hardness and heat resistance exists adjacently, so the ratio of Al at the Al component minimum content point is increased. The indicated X value was determined to be 0.15 to 0.30 .
Further, the Zr component at the Al component minimum content point is also included for the purpose of improving the high-temperature strength as described above, and thus adapting to high-speed cutting accompanied by high heat generation. Therefore, if the Y value is less than 0.01, it is desirable. The effect of improving the high temperature strength cannot be obtained. On the other hand, if the Y value exceeds 0.15, the high temperature hardness and the heat resistance tend to decrease, which causes the progress of wear. It was determined to be 0.15.
[0011]
(C) Interval between Al component maximum content point and Al component minimum content point If the distance is less than 0.01 μm, it is difficult to clearly form each point with the above composition, and as a result, the layer has a predetermined high temperature. In addition to ensuring hardness, heat resistance, and high-temperature strength, it is not possible to secure even better strength and toughness, and if the spacing exceeds 0.1 μm, each of the high-speed cutting processing under heavy cutting conditions If the point contains the highest content of Al component, the strength and toughness will be insufficient, and if the Al content is the lowest, the high temperature hardness and insufficient heat resistance will appear locally in the layer, causing chipping. The interval was determined to be 0.01 to 0.1 μm because it becomes easy and the progress of wear is promoted.
[0012]
(D) Overall average layer thickness of hard coating layer If the layer thickness is less than 1 μm, the desired wear resistance cannot be ensured. On the other hand, if the average layer thickness exceeds 15 μm, chipping tends to occur. Therefore, the average layer thickness was determined to be 1 to 15 μm.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Next, the coated carbide tool of the present invention will be specifically described with reference to examples.
Example 1
As raw material powders, WC powder, TiC powder, VC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, and Co powder, all having an average particle diameter of 1 to 3 μm, were prepared. The mixture is blended for 48 hours by a ball mill, dried and then pressed into a green compact at a pressure of 100 MPa, and this green compact is vacuumed at 6 Pa at a temperature of 1420 ° 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 a chip cemented carbide substrate A- made of a WC-based cemented carbide alloy having a chip shape of ISO standard / CNMG120212 1-A-5 and A-8-10 were 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 were prepared, and these raw material powders were blended in the blending composition shown in Table 2, wet mixed by a ball mill for 72 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 1520 ° C. for 1 hour, and after sintering, the cutting edge portion was subjected to a honing process of R: 0.03, and ISO standard / CNMG120212. Chip carbide substrates B-2 to B-5 made of TiCN cermet having the following chip shape were formed.
[0015]
Next, each of the above-mentioned chip carbide substrates A-1 to A-5, A-8 to 10 and B-2 to B-5 was ultrasonically washed in acetone and dried, as shown in FIG. Ti-Al-Zr for forming the highest point of Al component having various component compositions as a cathode electrode (evaporation source) on one side of the rotary table in the arc ion plating apparatus. Alloy, Ti-Al-Zr alloy for forming Al component minimum content point as cathode electrode (evaporation source) on the other side, facing each other across the rotary table, and also mounting metal Ti for bombard cleaning, The heater is heated to 500 ° C. with a heater while maintaining a vacuum of 0.5 Pa or less, and a −1000 V DC bias voltage is applied to the carbide substrate that rotates while rotating on the rotary table. In addition, a current of 100 A is passed between the metal Ti of the cathode electrode and the anode electrode to generate an arc discharge, thereby cleaning the surface of the carbide substrate with Ti bombard, and then introducing nitrogen gas as a reaction gas into the apparatus. A direct-current bias voltage of −30 V is applied to a carbide substrate that rotates while rotating on the rotary table while having a reaction atmosphere of 3 Pa, and each cathode electrode (Ti-Al— Zr alloy and Ti-Al-Zr alloy for forming Al component minimum content point) and an anode electrode to cause an arc discharge to flow along the thickness direction on the surface of the carbide substrate. The Al component highest content point and Al component lowest content point of the target composition shown in Table 3 are alternately present at the target interval shown in Table 3 alternately, and the A It has a component concentration distribution structure in which the Al component content changes continuously from the 1 component highest content point to the Al component lowest content point, from the Al component lowest content point to the Al component highest content point, and also in Table 3 By depositing a hard coating layer having a target overall layer thickness shown, a throwaway tip made of the surface coated cemented carbide of the present invention as the coated carbide tool of the present invention (hereinafter referred to as the present coated carbide chip) 1-12 Were manufactured respectively.
[0016]
Further, for the purpose of comparison, these chip superhard substrates A-1 to A-5, A-8 to 10 and B-2 to B-5 were ultrasonically washed in acetone and dried, respectively. 2 is loaded into a normal arc ion plating apparatus shown in FIG. 2, and Ti—Al—Zr alloys having various component compositions are mounted as a cathode electrode (evaporation source), and a metal Ti for bombard cleaning is also mounted. First, the inside of the apparatus was evacuated and kept at a vacuum of 0.5 Pa or less, and the inside of the apparatus was heated to 400 ° C. with a heater, and then a −1000 V DC bias voltage was applied to the cemented carbide substrate, and the cathode electrode A current of 90 A is passed between the metal Ti and the anode electrode to generate an arc discharge, thereby cleaning the surface of the carbide substrate with Ti bombardment, and then introducing nitrogen gas into the apparatus as a reaction gas to react 2 Pa. With the囲気, lowering the bias voltage applied to the carbide substrate to -200 V, the cathode electrode and to generate arc discharge between the anode electrode, the respective surfaces of the cemented carbide substrate with Table 4 By depositing a hard coating layer composed of a (Ti, Al, Zr) N layer having a target composition and a target layer thickness shown in FIG. Conventional surface-coated cemented carbide throwaway tips (hereinafter referred to as conventional coated carbide tips) 1 to 12 as hard tools were produced, respectively.
[0017]
Next, with the present invention coated carbide chips 1-12 and conventional coated carbide chips 1-12 , this is screwed to the tip of the tool steel tool with a fixing jig,
Work material: JIS / SNCM439 round bar,
Cutting speed: 300 m / min. ,
Cutting depth: 5.5 mm,
Feed: 0.15 mm / rev. ,
Cutting time: 5 minutes
Dry-type continuous high-speed high-cut cutting test of alloy steel under the conditions of
Work material: JIS · SCM440 lengthwise equidistant 4 vertical grooved round bar,
Cutting speed: 300 m / min. ,
Cutting depth: 1.6mm,
Feed: 0.5 mm / rev. ,
Cutting time: 5 minutes
Dry interrupted high-speed high-feed cutting test of alloy steel under the conditions of
Work material: JIS / FC300 round bar,
Cutting speed: 320 m / min. ,
Cutting depth: 5.5 mm,
Feed: 0.15 m / rev. ,
Cutting time: 5 minutes
The dry continuous high-speed, high-cut cutting test of cast iron was performed under the conditions described above, and the flank wear width of the cutting edge was measured in any cutting test. The measurement results are shown in Table 5 .
[0018]
[Table 1]

[0019]
[Table 2]

[0020]
[Table 3]

[0021]
[Table 4]

[0022]
[Table 5]

[0023]
(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 6 , further added with wax, ball milled in acetone for 50 hours, dried under reduced pressure, and then pressed into various compacts of a predetermined shape at a pressure of 100 MPa. The green compact is heated to a predetermined temperature in the range of 1370 to 1470 ° C. at a rate of temperature increase of 7 ° C./min in a 6 Pa vacuum atmosphere, held at this temperature for 1 hour, and then fired under furnace cooling conditions. Finally, the diameters are 8mm, 13mm, and 26 Three carbide substrate for forming a round bar sintered C-1 through C-8 of the m forming, further round bar sintered C-1, C of the three kinds of rod sintered body of the -2, C-4, C-5, and C-7, and from now on , in the combination shown in Table 6 , the diameter x length of the cutting edge portion is 6 mm x 13 mm, 10 mm x 22 mm, End mill cemented carbide substrates having dimensions of 20 mm × 45 mm and a four-blade square shape each having a twist angle of 30 degrees were manufactured.
[0024]
Next, these end mill carbide substrates were ultrasonically cleaned in acetone and dried, and then charged into the arc ion plating apparatus shown in FIG. The Al component highest content point and the Al component lowest content point of the target composition shown in Table 7 along the thickness direction alternately and repeatedly exist at the target intervals shown in Table 7 , and from the Al component highest content point Al component minimum content point, having a component concentration distribution structure in which the Al component content continuously changes from the Al component minimum content point to the Al component maximum content point, and also having the target total layer thickness shown in Table 7 By vapor-depositing the hard coating layer, end mills made of the surface coated cemented carbide of the present invention (hereinafter referred to as the present coated carbide end mill) 1 to 5 as the coated carbide tool of the present invention were produced.
[0025]
For comparison purposes, the above-mentioned end mill cemented carbide substrate was ultrasonically cleaned in acetone and dried, and charged into a normal arc ion plating apparatus shown in FIG. A hard coating layer composed of a (Ti, Al, Zr) N layer having the target composition and target layer thickness shown in Table 8 and having substantially no composition change along the thickness direction. By vapor deposition, conventional surface-coated cemented carbide end mills (hereinafter referred to as conventional coated carbide end mills) 1 to 5 as conventional coated carbide tools were produced, respectively.
[0026]
Next, the present invention coated cemented carbide end mills 1-5 and of the conventional coated cemented carbide end mills 1-5, the present invention coated cemented carbide end mills 1, 2 and conventional coated cemented carbide end mills 1 and 2,
Work material: Plane dimensions: 100 mm x 250 mm, thickness: 50 mm JIS / FC300 plate material,
Cutting speed: 320 m / min. ,
Axial cut: 10 mm
Radial notch: 1.8mm,
Table feed: 210 mm / min,
With respect to the cast iron wet high speed high cutting side cutting test, the present coated carbide end mills 3 and 4 and the conventional coated carbide end mills 3 and 4
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / SCM440 plate material,
Cutting speed: 300 m / min. ,
Axial cut: 18mm,
Radial notch: 3mm,
Table feed: 195mm / min,
About the wet high speed high cutting side cutting test of the alloy steel under the conditions of the present invention, the coated carbide end mill 5 of the present invention and the conventional coated carbide end mill 5 ,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / SNCM439 plate material,
Cutting speed: 290 m / min. ,
Axial cut: 40 mm,
Radial notch: 6mm,
Table feed: 100 mm / min,
Wet high-speed high-cut side cutting test of alloy steel under the above conditions, and the flank wear width of the outer peripheral edge of the cutting edge in any wet side cutting test (using water-soluble cutting oil) The cutting length up to 0.1 mm was measured. The measurement results are shown in Tables 7 and 8 , respectively.
[0027]
[Table 6]

[0028]
[Table 7]

[0029]
[Table 8]

[0030]
(Example 3)
Round bar sintered bodies C-2, C-3, C- of the three types of round bar sintered bodies C-1 to C- 8 having diameters of 8 mm, 13 mm, and 26 mm manufactured in Example 2 above. 5 to C-8, and in the grinding process, the diameter x length of the groove forming part is 4 mm × 13 mm, 8 mm × 22 mm, and 16 mm × 45 mm, respectively, in combination shown in Table 6 , A drill carbide substrate having a two-blade shape with a twist angle of 30 degrees was also produced.
[0031]
Next, honing is performed on the cutting blades of these drill carbide substrates , ultrasonic cleaning in acetone is performed, and the dried state is inserted into the arc ion plating apparatus shown in FIG. And the Al component highest content point and Al component lowest content point of the target composition shown in Table 9 along the layer thickness direction alternately and repeatedly at the target interval shown in Table 9 , and It has a component concentration distribution structure in which the Al component content continuously changes from the Al component highest content point to the Al component lowest content point, from the Al component lowest content point to the Al component highest content point, and also in Table 9 By vapor-depositing a hard coating layer having a target overall layer thickness shown, drills made of the surface-coated cemented carbide of the present invention (hereinafter referred to as the present coated carbide drill) 1-6 as the coated carbide tool of the present invention are respectively provided. Manufactured It was.
[0032]
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 10 under the same conditions as in Example 1, and substantially changed in composition along the thickness direction. no (Ti, Al, Zr) by depositing hard coating layer consisting of N layers, the conventional surface-coated cemented carbide drills of the conventional coated cemented carbide (hereinafter, referred to as conventional coated cemented carbide drills) 1-6 Were manufactured respectively.
[0033]
Next, of the present invention coated carbide drills 1 to 6 and the conventional coated carbide drills 1 to 6 , the present invention coated carbide drills 1 and 2 and the conventional coated carbide drills 1 and 2 ,
Work material: Plane dimensions: 100 mm x 250 mm, thickness: 50 mm JIS / FC300 plate material,
Cutting speed: 200 m / min. ,
Feed: 0.5mm / rev,
Hole depth: 10mm
For the cast iron wet high-speed high-feed drilling test under the conditions of the present invention, the coated carbide drills 3 and 4 of the present invention and the conventional coated carbide drills 3 and 4 ,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / SCM440 plate material,
Cutting speed: 175 m / min. ,
Feed: 0.4mm / rev,
Hole depth: 1.5mm
Wet high-speed high feed drilling cutting test under the conditions of alloy steel, the present invention coated carbide drills 5,6 and conventional coated cemented carbide drills 5,6,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / SNCM439 plate material,
Cutting speed: 175 m / min. ,
Feed: 0.5mm / rev,
Hole depth: 30mm
Wet high-speed high-feed drilling machining test of alloy steel under the above conditions, and the flank wear width of the tip cutting edge surface is 0.3 mm in any wet high-speed drilling machining test (using water-soluble cutting oil) The number of drilling processes was measured. The measurement results are shown in Tables 9 and 10 , respectively.
[0034]
[Table 9]

[0035]
[Table 10]

[0036]
In the hard coating layer which comprises this invention coated carbide tip 1-12 as this invention coated carbide tool obtained as a result, this invention coated carbide end mill 1-5 , and this invention coated carbide drill 1-6 Composition of Al component maximum content point and Al component minimum content point, as well as conventional coated carbide tips 1-12 , conventional coated carbide end mills 1-5 , and conventional coated carbide drills 1-6 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 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】
From the results shown in Tables 3 to 10 , the hard coating layer has a predetermined high-temperature hardness and heat resistance, and further has an Al component highest content point having a high-temperature strength and a strength and toughness far superior to each other. Al component content from the lowest Al component content point to the Al component lowest content point, from the Al component lowest content point to the Al component highest content point The coated carbide tool of the present invention having a component concentration distribution structure in which the material continuously changes is high-speed cutting such as various steels and cast iron, heavy cutting conditions such as high cutting with high mechanical impact and high feed The hard coating layer exhibits excellent chipping resistance even in the case of (Ti, Al, Zr) N layer with substantially no composition change along the thickness direction. Conventional coating consisting of In hard tool, the fast cutting in heavy cutting conditions because strength and toughness insufficiency of the hard coating layer, 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 cope with the conversion sufficiently satisfactorily.
[Brief description of the drawings]
FIG. 1 shows an arc ion plating apparatus used to form a hard coating layer constituting a coated carbide tool of the present invention, wherein (a) is a schematic plan view and (b) is a schematic front view.
FIG. 2 is a schematic explanatory view of a normal arc ion plating apparatus used to form a hard coating layer constituting a conventional coated carbide tool.

Claims

A turning table for mounting either or both of a tungsten carbide base cemented carbide substrate and a titanium carbonitride-based cermet substrate is provided at the center of the apparatus, and Ti for forming the highest Al component content is placed on one side of the rotating table. -An arc ion plating apparatus in which an Al-Zr alloy and a Ti-Al-Zr 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 layer of Ti, Al and Zr In the overall average layer surface-coated cemented carbide cutting tool comprising depositing a thickness of 1 to 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,
Furthermore, the Al component maximum content point, composition _{formula: (Ti 1- (X + Y} ) Al X Zr Y) N ( provided that an atomic ratio, X is 0.45 to 0.65, Y: 0.01 ~ 0.15)
The Al component minimum content point, composition _{formula: (Ti 1- (X + Y} ) Al X Zr Y) N ( provided that an atomic ratio, X is 0.15 to 0.30, Y: .01 to 0 .15)
And the interval between the adjacent Al component highest content point and 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.