JP2004025335A

JP2004025335A - Surface-coated cemented carbide cutting tool with hard coat layer exhibiting excellent wear resistance under high-speed double cutting condition

Info

Publication number: JP2004025335A
Application number: JP2002183770A
Authority: JP
Inventors: Hidemitsu Takaoka; 高岡　秀充; Keiji Nakamura; 中村　惠滋
Original assignee: Mitsubishi Materials Corp; Mitsubishi Materials Kobe Tools Corp
Current assignee: Mitsubishi Materials Corp; Mitsubishi Materials Kobe Tools Corp
Priority date: 2002-06-25
Filing date: 2002-06-25
Publication date: 2004-01-29
Anticipated expiration: 2022-06-25
Also published as: JP3978775B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-coated cemented carbide cutting tool having a hard coat layer which exhibits excellent wear resistance under a high-speed double cutting condition. <P>SOLUTION: On the surface of a WC-group carbide base body or titanium carbide and nitride-based cermet base, the hard coat layer 1-15μm in thickness consisting of a composite nitride of Al, Ti and Zr is formed so as to have a component concentration distribution structure in which the Al highest content point (point A) and the Ti highest content point (point B) are alternately repeatedly present at prescribed intervals along the layer thickness direction, and the Al and Ti contents are continuously changed from the point to the point B or from the point B to the point A. The point A and the point B satisfy a composition formula (Al<SB>1-(X+Y)</SB>Ti<SB>X</SB>Zr<SB>Y</SB>)N (wherein X represents 0.05-0.30, by atomic ratio, and Y represents 0.01-0.15) and a composition formula (Ti<SB>1-(Z+Y)</SB>Al<SB>Z</SB>Zr<SB>Y</SB>)N (wherein Z represents 0.1-0.35, by atomic ration, and Y represents 0.01-0.15), respectively, and the space between the adjacent points A and B is set to 0.01-0.1μm. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
この発明は、硬質被覆層がすぐれた高温硬さと耐熱性、さらに高強度と高靭性を有し、したがって各種の鋼や鋳鉄などの切削加工を、特に高熱発生を伴う高速で、かつ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、硬質被覆層がチッピング（微小欠け）などの発生なく、すぐれた耐摩耗性を発揮する表面被覆超硬合金製切削工具（以下、被覆超硬工具という）に関するものである。
【０００２】
【従来の技術】
一般に、被覆超硬工具には、各種の鋼や鋳鉄などの被削材の旋削加工や平削り加工にバイトの先端部に着脱自在に取り付けて用いられるスローアウエイチップ、穴あけ切削加工などに用いられるドリルやミニチュアドリル、さらに面削加工や溝加工、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−（Ｍ＋Ｙ）}Ａｌ_ＭＺｒ_Ｙ）Ｎ（ただし、原子比で、Ｍは０．４０〜０．６５、Ｙは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層が高温硬さおよび耐熱性（高温特性）と強度および靭性を有し、さらに高温強度も具備することと相俟って、高熱発生を伴う各種の鋼や鋳鉄などの連続切削や断続切削加工ですぐれた切削性能を発揮す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−８０Ｖ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も強く、これに伴い、切削加工は高速化の傾向を深め、かつ高切り込みや高送りなどの重切削条件での切削加工が強く求められる傾向にあるが、上記の従来被覆超硬工具においては、これを通常の切削加工条件で用いた場合には問題はないが、特に切削加工を高速で、かつ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、硬質被覆層の高温硬さおよび耐熱性が不足し、かつ強度および靭性も不十分であるために、硬質被覆層の摩耗進行が一段と促進し、かつチッピングも発生し易くなることから、比較的短時間で使用寿命に至るのが現状である。
【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条件で硬質被覆層がすぐれた耐摩耗性を発揮する被覆超硬工具を開発すべく、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、したがって均質な高温硬さと耐熱性、強度と靭性を有し、さらに高温強度を有するが、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−Ｔｉ−Ｚｒ合金、他方側に相対的にＴｉ含有量の高い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、蒸着形成される硬質被覆層の層厚均一化を図る目的で超硬基体自体も自転させながら、前記の両側のカソード電極（蒸発源）とアノード電極との間にアーク放電を発生させて、前記超硬基体の表面にＡｌとＴｉとＺｒの複合窒化物［以下、（Ａｌ−Ｔｉ，Ｚｒ）Ｎで示す］層を形成すると、この結果の（Ａｌ−Ｔｉ，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相対的にＡｌ含有量の高いＡｌ−Ｔｉ−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Ｔｉ含有量の高い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Ｔｉ最高含有点が形成され、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最高含有点とＴｉ最高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最高含有点から前記Ｔｉ最高含有点、前記Ｔｉ最高含有点から前記Ａｌ最高含有点へＡｌおよびＴｉ含有量がそれぞれ連続的に変化する成分濃度分布構造をもつようになること。
【０００７】
（ｂ）上記（ａ）の繰り返し連続変化成分濃度分布構造の（Ａｌ−Ｔｉ，Ｚｒ）Ｎ層の形成において、対向配置の一方側のカソード電極（蒸発源）であるＡｌ−Ｔｉ−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高いものとし、かつ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最高含有点が、組成式：（Ａｌ_{１−（Ｘ＋Ｙ）}Ｔｉ_ＸＺｒ_Ｙ）Ｎ（ただし、原子比で、Ｘは０．０５〜０．３０、Ｙは０．０１〜０．１５を示す）、
上記Ｔｉ最高含有点が、組成式：（Ｔｉ_{１−（Ｚ＋Ｙ）}Ａｌ_ＺＺｒ_Ｙ）Ｎ（ただし、原子比で、Ｚは０．１０〜０．３５、Ｙは０．０１〜０．１５を示す）、
をそれぞれ満足し、かつ隣り合う上記Ａｌ最高含有点とＴｉ最高含有点の厚さ方向の間隔を０．０１〜０．１μｍとすると、
上記Ａｌ最高含有点部分では、上記の従来（Ｔｉ，Ａｌ，Ｚｒ）Ｎ層に比してＡｌ含有量が相対的に高くなることから、より一段とすぐれた高温硬さと耐熱性を示し、一方上記Ｔｉ最高含有点部分では、前記従来（Ｔｉ，Ａｌ，Ｚｒ）Ｎ層に比してＴｉ含有量が相対的に高くなることから、一段と高い強度と靭性を具備し、かつこれらＡｌ最高含有点とＴｉ最高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一段とすぐれた強度と靭性、およびすぐれた高温硬さと耐熱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（Ａｌ−Ｔｉ，Ｚｒ）Ｎ層からなる被覆超硬工具は、Ｚｒ成分によってもたらされる高温強度の向上効果と相俟って、各種の鋼や鋳鉄などの切削加工を、特に高熱発生および高い機械的衝撃を伴う、高速重切削条件で行なった場合にも、硬質被覆層にチッピングの発生なく、すぐれた耐摩耗性を発揮するようになること。
以上（ａ）および（ｂ）に示される研究結果を得たのである。
【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、（Ａｌ−Ｔｉ，Ｚｒ）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、厚さ方向にそって、Ａｌ最高含有点とＴｉ最高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最高含有点から前記Ｔｉ最高含有点、前記Ｔｉ最高含有点から前記Ａｌ最高含有点へＡｌおよびＴｉ含有量がそれぞれ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最高含有点が、組成式：（Ａｌ_{１−（Ｘ＋Ｙ）}Ｔｉ_ＸＺｒ_Ｙ）Ｎ（ただし、原子比で、Ｘは０．０５〜０．３０、Ｙは０．０１〜０．１５を示す）、
上記Ｔｉ最高含有点が、組成式：（Ｔｉ_{１−（Ｚ＋Ｙ）}Ａｌ_ＺＺｒ_Ｙ）Ｎ（ただし、原子比で、Ｚは０．１０〜０．３５、Ｙは０．０１〜０．１５を示す）、
を満足し、かつ隣り合う上記Ａｌ最高含有点とＴｉ最高含有点の間隔が、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摩耗性を発揮する被覆超硬工具に特徴を有するものである。
【０００９】
つぎに、この発明の被覆超硬工具において、これを構成する硬質被覆層の構成を上記の通りに限定した理由を説明する。
（ａ）Ａｌ最高含有点の組成
（Ａｌ−Ｔｉ，Ｚｒ）Ｎ層のＡｌ最高含有点におけるＡｌ成分は、高温硬さおよび耐熱性を向上させ、同Ｔｉ成分は強度および靭性を向上させ、さらに同Ｚｒ成分は高温強度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、Ｚｒ成分による高温強度の向上効果と相俟って、高熱発生を伴う高速切削に適合したものになるが、Ｔｉの割合を示すＸ値がＡｌとＺｒの合量に占める割合（原子比）で０．０５未満になると、相対的にＡｌの割合が多くなり過ぎて、高強度および高靭性を有するＴｉ最高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Ｔｉ成分の割合を示すＸ値が同０．３０を越えると、相対的にＡｌの割合が少なくなり過ぎて、所望のすぐれた高温硬さおよび耐熱性を確保することができなくなるものであり、またＺｒ成分の割合を示す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、強度および靭性が急激に低下するようになることから、Ｘ値を０．０５〜０．３０、Ｙ値を０．０１〜０．１５とそれぞれ定めた。
【００１０】
（ｂ）Ｔｉ最高含有点の組成
上記の通りＡｌ最高含有点は一段とすぐれた高温硬さと耐熱性を有するが、反面強度および靭性の劣るものであるため、このＡｌ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、これによって高強度および高靭性を有するようになるＴｉ最高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Ｚ値がＴｉとＺｒの合量に占める割合（原子比）で０．３５を越えると、相対的にＡｌの割合が多くなり過ぎて、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Ｚ値が同じく０．１０未満になると、相対的にＴｉの割合が多くなり過ぎて、Ｔｉ最高含有点に所望の高温硬さおよび耐熱性を確保することができず、摩耗促進の原因となることから、Ｚ値を０．１０〜０．３５と定めたものであり、またＺｒ成分の割合を示すＹ値は上記のＡｌ最高含有点におけると同じ理由で０．０１〜０．１５と定めた。
【００１１】
（ｃ）Ａｌ最高含有点とＴｉ最高含有点間の間隔
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、この結果層に一段とすぐれた強度と靭性、さらにすぐれた高温硬さと耐熱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最高含有点であれば強度および靭性不足、Ｔｉ最高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、これが原因で切刃に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、Ｃｒ_３Ｃ_２粉末、およびＣｏ粉末を用意し、これら原料粉末を、表１に示される配合組成に配合し、ボールミルで６０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：１４０５℃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基超硬合金製の超硬基体Ａ１〜Ａ１０を形成した。
【００１４】
また、原料粉末として、いずれも０．５〜２μｍの平均粒径を有するＴｉＣＮ（重量比でＴｉＣ／ＴｉＮ＝５０／５０）粉末、Ｍｏ_２Ｃ粉末、ＺｒＣ粉末、ＮｂＣ粉末、ＴａＣ粉末、ＷＣ粉末、Ｃｏ粉末、およびＮｉ粉末を用意し、これら原料粉末を、表２に示される配合組成に配合し、ボールミルで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：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・ＣＮＭＧ１２０４１２のチップ形状をもったＴｉＣＮ系サーメット製の超硬基体Ｂ１〜Ｂ６を形成した。
【００１５】
ついで、上記の超硬基体Ａ１〜Ａ１０およびＢ１〜Ｂ６のそれぞれを、アセトン中で超音波洗浄し、乾燥した状態で、図１に示されるアークイオンプレーティング装置内の回転テーブル上に外周部にそって装着し、一方側のカソード電極（蒸発源）として、種々の成分組成をもったＴｉ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、種々の成分組成をもったＡｌ最高含有点形成用Ａｌ−Ｔｉ−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Ｔｉ最高含有点形成用Ｔｉ−Ａｌ−Ｚｒ合金およびＡｌ最高含有点形成用Ａｌ−Ｔｉ−Ｚｒ合金）とアノード電極との間に１４０Ａの電流を流してアーク放電を発生させ、もって前記超硬基体の表面に、層厚方向に沿って表３，４に示される目標組成のＡｌ最高含有点とＴｉ最高含有点とが交互に同じく表３，４に示される目標間隔で繰り返し存在し、かつ前記Ａｌ最高含有点から前記Ｔｉ最高含有点、前記Ｔｉ最高含有点から前記Ａｌ最高含有点へＡｌおよびＴｉ含有量がそれぞれ連続的に変化する成分濃度分布構造を有し、かつ同じく表３，４に示される目標全体層厚の硬質被覆層を蒸着することにより、本発明被覆超硬工具としての本発明表面被覆超硬合金製スローアウエイチップ（以下、本発明被覆超硬チップと云う）１〜１６をそれぞれ製造した。
【００１６】
また、比較の目的で、これら超硬基体Ａ１〜Ａ１０およびＢ１〜Ｂ６を、アセトン中で超音波洗浄し、乾燥した状態で、それぞれ図２に示される通常のアークイオンプレーティング装置に装入し、カソード電極（蒸発源）として種々の成分組成をもったＴｉ−Ａｌ−Ｚｒ合金を装着し、さらに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、超硬基体に−８０Ｖの直流バイアス電圧を印加し、前記カソード電極のＴｉ−Ａｌ−Ｚｒ合金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、もって前記超硬基体Ａ１〜Ａ１０およびＢ１〜Ｂ６のそれぞれの表面に、表５，６に示される目標組成および目標層厚を有し、かつ層厚方向に沿って実質的に組成変化のない（Ｔｉ，Ａｌ，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）１〜１６をそれぞれ製造した。
【００１７】
つぎに、上記本発明被覆超硬チップ１〜１６および従来被覆超硬チップ１〜１６について、これを工具鋼製バイトの先端部に固定治具にてネジ止めした状態で、
被削材：ＪＩＳ・Ｓ２０Ｃ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、
の条件での炭素鋼の乾式連続高速高切り込み切削加工試験、
被削材：ＪＩＳ・ＳＳ４００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：１．８ｍｍ、
送り：０．５ｍｍ／ｒｅｖ．、
切削時間：５分、
の条件での軟鋼の乾式断続高速高送り切削加工試験、さらに、
被削材：ＪＩＳ・ＦＣ２００の丸棒、
切削速度：３３０ｍ／ｍｉｎ．、
切り込み：６ｍｍ、
送り：０．１６ｍｍ／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７に示した。
【００１８】
【表１】

【００１９】
【表２】

【００２０】
【表３】

【００２１】
【表４】

【００２２】
【表５】

【００２３】
【表６】

【００２４】
【表７】

【００２５】
（実施例２）
原料粉末として、平均粒径：５．５μｍを有する中粗粒ＷＣ粉末、同０．８μｍの微粒ＷＣ粉末、同１．３μｍのＴａＣ粉末、同１．２μｍのＮｂＣ粉末、同１．２μｍのＺｒ粉末、同２．３μｍのＣｒ_３Ｃ_２粉末、同１．５μｍのＶＣ粉末、同１．０μｍの（Ｔｉ，Ｗ）Ｃ粉末、および同１．８μｍのＣｏ粉末を用意し、これら原料粉末をそれぞれ表８に示される配合組成に配合し、さらにワックスを加えてアセトン中で２４時間ボールミル混合し、減圧乾燥した後、６０ＭＰａの圧力で所定形状の各種の圧粉体にプレス成形し、これらの圧粉体を、６Ｐａの真空雰囲気中、７℃／分の昇温速度で１３７０〜１４７０℃の範囲内の所定の温度に昇温し、この温度に１時間保持後、炉冷の条件で焼結して、直径が８ｍｍ、１３ｍｍ、および２６ｍｍの３種の超硬基体形成用丸棒焼結体を形成し、さらに前記の３種の丸棒焼結体から、研削加工にて、表８に示される組合せで、切刃部の直径×長さがそれぞれ６ｍｍ×１３ｍｍ、１０ｍｍ×２２ｍｍ、および２０ｍｍ×４５ｍｍの寸法、並びにいずれもねじれ角：３０度の４枚刃スクエア形状をもった超硬基体（エンドミル）Ｃ−１〜Ｃ−８をそれぞれ製造した。
【００２６】
ついで、これらの超硬基体（エンドミル）Ｃ−１〜Ｃ−８を、アセトン中で超音波洗浄し、乾燥した状態で、同じく図１に示されるアークイオンプレーティング装置に装入し、上記実施例１と同一の条件で、厚さ方向に沿って表９に示される目標組成のＡｌ最高含有点とＴｉ最高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最高含有点から前記Ｔｉ最高含有点、前記Ｔｉ最高含有点から前記Ａｌ最高含有点へＡｌおよびＴｉ含有量がそれぞれ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エンドミル（以下、本発明被覆超硬エンドミルと云う）１〜８をそれぞれ製造した。
【００２７】
また、比較の目的で、上記の超硬基体（エンドミル）Ｃ−１〜Ｃ−８を、アセトン中で超音波洗浄し、乾燥した状態で、同じく図２に示される通常のアークイオンプレーティング装置に装入し、上記実施例１と同一の条件で、表１０に示される目標組成および目標層厚を有し、かつ層厚方向に沿って実質的に組成変化のない（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）１〜８をそれぞれ製造した。
【００２８】
つぎに、上記本発明被覆超硬エンドミル１〜８および従来被覆超硬エンドミル１〜８のうち、本発明被覆超硬エンドミル１〜３および従来被覆超硬エンドミル１〜３については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＦＣ２００の板材、
切削速度：３３０ｍ／ｍｉｎ．、
軸方向切り込み：１０ｍｍ、
径方向切り込み：２ｍｍ、
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４〜６および従来被覆超硬エンドミル４〜６については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＳＳ４００の板材、
切削速度：３１０ｍ／ｍｉｎ．、
軸方向切り込み：１８ｍｍ、
径方向切り込み：３．２ｍｍ、
テーブル送り：１９０ｍｍ／分、
の条件での軟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７，８および従来被覆超硬エンドミル７，８については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・Ｓ２０Ｃの板材、
切削速度：３１０ｍ／ｍｉｎ．、
軸方向切り込み：４０ｍｍ、
径方向切り込み：６．２ｍｍ、
テーブル送り：１００ｍｍ／分、
の条件での炭素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９、１０にそれぞれ示した。
【００２９】
【表８】

【００３０】
【表９】

【００３１】
【表１０】

【００３２】
（実施例３）
上記の実施例２で製造した直径が８ｍｍ（超硬基体Ｃ−１〜Ｃ−３形成用）、１３ｍｍ（超硬基体Ｃ−４〜Ｃ−６形成用）、および２６ｍｍ（超硬基体Ｃ−７、Ｃ−８形成用）の３種の丸棒焼結体を用い、この３種の丸棒焼結体から、研削加工にて、溝形成部の直径×長さがそれぞれ４ｍｍ×１３ｍｍ（超硬基体Ｄ−１〜Ｄ−３）、８ｍｍ×２２ｍｍ（超硬基体Ｄ−４〜Ｄ−６）、および１６ｍｍ×４５ｍｍ（超硬基体Ｄ−７、Ｄ−８）の寸法、並びにいずれもねじれ角：３０度の２枚刃形状をもった超硬基体（ドリル）Ｄ−１〜Ｄ−８をそれぞれ製造した。
【００３３】
ついで、これらの超硬基体（ドリル）Ｄ−１〜Ｄ−８の切刃に、ホーニングを施し、アセトン中で超音波洗浄し、乾燥した状態で、同じく図１に示されるアークイオンプレーティング装置に装入し、上記実施例１と同一の条件で、層厚方向に沿って表１１に示される目標組成のＡｌ最高含有点とＴｉ最高含有点とが交互に同じく表１１に示される目標間隔で繰り返し存在し、かつ前記Ａｌ最高含有点から前記Ｔｉ最高含有点、前記Ｔｉ最高含有点から前記Ａｌ最高含有点へＡｌおよびＴｉ含有量がそれぞれ連続的に変化する成分濃度分布構造を有し、かつ同じく表１１に示される目標全体層厚の硬質被覆層を蒸着することにより、本発明被覆超硬工具としての本発明表面被覆超硬合金製ドリル（以下、本発明被覆超硬ドリルと云う）１〜８をそれぞれ製造した。
【００３４】
また、比較の目的で、上記の超硬基体（ドリル）Ｄ−１〜Ｄ−８の切刃に、ホーニングを施し、アセトン中で超音波洗浄し、乾燥した状態で、同じく図２に示される通常のアークイオンプレーティング装置に装入し、上記実施例１と同一の条件で、表１２に示される目標組成および目標層厚を有し、かつ層厚方向に沿って実質的に組成変化のない（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）１〜８をそれぞれ製造した。
【００３５】
つぎに、上記本発明被覆超硬ドリル１〜８および従来被覆超硬ドリル１〜８のうち、本発明被覆超硬ドリル１〜３および従来被覆超硬ドリル１〜３については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＳＳ４００の板材、
切削速度：２００ｍ／ｍｉｎ．、
送り：０．４５ｍｍ／ｒｅｖ、
穴深さ：１０ｍｍ、
の条件での軟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４〜６および従来被覆超硬ドリル４〜６については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・Ｓ２０Ｃの板材、
切削速度：２１０ｍ／ｍｉｎ．、
送り：０．４５ｍｍ／ｒｅｖ、
穴深さ：１５ｍｍ、
の条件での炭素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７，８および従来被覆超硬ドリル７，８については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＦＣ２００の板材、
切削速度：２３０ｍ／ｍｉｎ．、
送り：０．６ｍｍ／ｒｅｖ、
穴深さ：３０ｍｍ、
の条件での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、いずれの湿式穴あけ切削加工試験（水溶性切削油使用）でも先端切刃面の逃げ面摩耗幅が０．３ｍｍに至るまでの穴あけ加工数を測定した。この測定結果を表１１、１２にそれぞれ示した。
【００３６】
【表１１】

【００３７】
【表１２】

【００３８】
この結果得られた本発明被覆超硬工具としての本発明被覆超硬チップ１〜１６、本発明被覆超硬エンドミル１〜８、および本発明被覆超硬ドリル１〜８を構成する硬質被覆層におけるＡｌ最高含有点とＴｉ最高含有点の組成、並びに従来被覆超硬工具としての従来被覆超硬チップ１〜１６、従来被覆超硬エンドミル１〜８、および従来被覆超硬ドリル１〜８の硬質被覆層の組成をオージェ分光分析装置を用いて測定したところ、それぞれ目標組成と実質的に同じ組成を示した。
また、これらの本発明被覆超硬工具の硬質被覆層におけるＡｌ最高含有点とＴｉ最高含有点間の間隔、およびこれの全体層厚、並びに従来被覆超硬工具の硬質被覆層の厚さを、走査型電子顕微鏡を用いて断面測定したところ、いずれも目標値と実質的に同じ値を示した。
【００３９】
【発明の効果】
表３〜１２に示される結果から、硬質被覆層が厚さ方向に、相対的に一段とすぐれた高温硬さと耐熱性を有するＡｌ最高含有点と、同じく相対的に高い強度と靭性を有するＴｉ最高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最高含有点から前記Ｔｉ最高含有点、前記Ｔｉ最高含有点から前記Ａｌ最高含有点へＡｌおよびＴｉ含有量がそれぞれ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、いずれも前記硬質被覆層がＺｒ成分の含有によってすぐれた高温強度を具備することと相俟って、各種の鋼や鋳鉄などの切削加工を、高温発生を伴う高速条件で、かつ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、硬質被覆層にチッピングの発生なく、すぐれた耐摩耗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、前記の高速重切削条件では、前記硬質被覆層の高温硬さおよび耐熱性不足、さらに強度および靭性不足が原因で、摩耗進行が速く、かつチッピングも発生し易いことから、比較的短時間で使用寿命に至ることが明らかである。
上述のように、この発明の被覆超硬工具は、通常の条件での切削加工は勿論のこと、特に各種の鋼や鋳鉄などの切削加工を、高熱発生および高い機械的衝撃を伴う高速重切削条件で行なった場合にも、チッピングの発生なく、すぐれた耐摩耗性を発揮するものであるから、切削加工の省力化および省エネ化、さらに低コスト化に十分満足に対応できるものである。
【図面の簡単な説明】
【図１】この発明の被覆超硬工具を構成する硬質被覆層を形成するのに用いたアークイオンプレーティング装置を示し、（ａ）は概略平面図、（ｂ）は概略正面図である。
【図２】従来被覆超硬工具を構成する硬質被覆層を形成するのに用いた通常のアークイオンプレーティング装置の概略説明図である。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides a hard coating layer having excellent high-temperature hardness and heat resistance, as well as high strength and high toughness. Therefore, cutting of various steels and cast irons can be performed at high speed with high heat generation and high mechanical properties. When coated under heavy cutting conditions such as high cutting and high feed with impact, the hard coating layer has excellent wear resistance without chipping (micro chipping) etc. Hereinafter, referred to as a coated carbide tool).
[0002]
[Prior art]
In general, coated carbide tools are used for throw-away inserts, drilling, etc., which are removably attached to the tip of a cutting tool for turning or planing of various materials such as steel and cast iron. There are solid type end mills used for drilling and miniature drills, as well as for face milling, grooving, shoulder processing, etc., and the cutting is performed in the same manner as the solid type end mill by detachably attaching the throw-away tip. A throw-away end mill tool and the like are known.
[0003]
Further, as a coated cemented carbide tool, a substrate made of tungsten carbide (hereinafter, referred to as WC) -based cemented carbide or titanium carbonitride (hereinafter, referred to as TiCN) -based cermet (hereinafter, these are collectively referred to as a cemented carbide substrate) surface, composition _{_{formula): (Ti 1- (M +}} Y) Al M Zr Y) N ( provided that an atomic ratio, M is from 0.40 to 0.65, Y represents a 0.01 to 0.15) Coated hard tool formed by physical vapor deposition of a hard coating layer composed of a composite nitride of Ti, Al, and Zr (hereinafter, referred to as (Ti, Al, Zr) N) with an average thickness of 1 to 15 μm. In such a coated carbide tool, the (Ti, Al, Zr) N layer constituting the hard coating layer has high-temperature hardness and heat resistance (high-temperature properties), strength and toughness, and also has high-temperature strength. In combination with the provision of various types of steel and casting with high heat generation It is also known to exhibit cutting performance with superior in continuous cutting or interrupted cutting of such.
[0004]
Furthermore, the above-mentioned coated carbide tool is charged with the above-mentioned carbide substrate in an arc ion plating apparatus, which is a kind of physical vapor deposition apparatus shown schematically in FIG. 2, for example, and the inside of the apparatus is heated by a heater. For example, an arc discharge is generated between an anode electrode and a cathode electrode (evaporation source) on which 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. Simultaneously, a 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 under the condition that a bias voltage of, for example, -80 V is applied. In addition, it is also known that it is manufactured by 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 equipment has been remarkably improved, and on the other hand, there is a strong demand for labor-saving and energy-saving cutting, as well as low cost. There is a tendency to strongly demand cutting under heavy cutting conditions such as high feed, but in the above-mentioned conventional coated carbide tools, there is no problem if this is used under normal cutting conditions, but especially cutting When processing at high speed and heavy cutting conditions such as high cutting and high feed with high mechanical impact, the hard coating layer lacks high-temperature hardness and heat resistance, and also has insufficient strength and toughness Therefore, the progress of abrasion of the hard coating layer is further promoted, and chipping is also easily generated.
[0006]
[Means for Solving the Problems]
In view of the above, the present inventors have developed the above-mentioned conventional coated cemented carbide tool in order to develop a coated cemented carbide tool in which the hard coating layer exhibits excellent wear resistance particularly under high-speed heavy cutting conditions. Focusing on the hard coating layer that constitutes
(A) The (Ti, Al, Zr) N layer constituting the conventional coated carbide tool formed by using the arc ion plating apparatus shown in FIG. 2 is substantially uniform over the entire thickness. It has a uniform high-temperature hardness and heat resistance, strength and toughness, and has high-temperature strength. For example, FIG. 1A is a schematic plan view, and FIG. An arc ion plating apparatus having the structure shown, that is, a rotary table for mounting a carbide substrate is provided at the center of the apparatus, and an Al-Ti-Zr alloy having a relatively high Al content is provided on one side with the rotary table interposed therebetween. Using an arc ion plating apparatus in which a Ti-Al-Zr alloy having a relatively high Ti content is disposed on the other side as a cathode electrode (evaporation source), a plurality of arc ion plating apparatuses are provided along the outer periphery of the turntable of the apparatus. Carbide The body is mounted in a ring shape, and in this state, the atmosphere in the apparatus is set to a nitrogen atmosphere, and the rotary table is rotated, and while the thickness of the hard coating layer formed by vapor deposition is made uniform, the super hard substrate itself is also rotated. An arc discharge is generated between the cathode electrode (evaporation source) on both sides and the anode electrode, and a composite nitride of Al, Ti and Zr [hereinafter, (Al-Ti, Zr ) N] layer, the resulting (Al-Ti, Zr) N layer has the above-mentioned carbide substrate disposed in a ring shape on a rotary table and having a relatively high Al content on one side. The point of highest Al content is formed in the layer at the point of closest approach to the cathode electrode (evaporation source) of the high amount Al-Ti-Zr alloy, and the cemented carbide substrate has a relatively high Ti content on the other side. High Ti-Al-Zr alloy At the point closest to the cathode electrode, the highest Ti content point is formed in the layer, and by rotating the rotary table, the highest Al content point and highest Ti content point alternate in the layer along the thickness direction at a predetermined interval. And the component concentration distribution structure in which the Al and Ti contents continuously change from the highest Al content point to the highest Ti content point, and from the highest Ti content point to the highest Al content point, respectively. thing.
[0007]
(B) In the formation of the (Al-Ti, Zr) N layer having the repetitive and continuously changing component concentration distribution structure of (a), the Al-Ti-Zr alloy as the cathode electrode (evaporation source) on one side of the opposed arrangement is used. The Al content is made relatively higher than the Al content of the conventional Ti-Al-Zr alloy, and the Al content in the Ti-Al-Zr alloy which is the cathode electrode (evaporation source) on the other side While making the amount relatively lower than the Al content of the above-mentioned conventional Ti-Al-Zr alloy, and controlling the rotation speed of the turntable on which the carbide substrate is mounted,
The Al highest content point, the composition _{_{formula: (Al 1- (X + Y}} ) Ti X Zr Y) N ( provided that an atomic ratio, X is 0.05 to 0.30, Y is a 0.01-0.15 Show),
The Ti maximum content point, composition _{_{formula: (Ti 1- (Z + Y}} ) Al Z Zr Y) N ( provided that an atomic ratio, Z is 0.10 to 0.35, Y is a 0.01-0.15 Show),
Are satisfied, and the distance in the thickness direction between the adjacent Al maximum content point and Ti maximum content point is 0.01 to 0.1 μm,
Since the Al content is relatively higher in the Al highest content portion than in the conventional (Ti, Al, Zr) N layer, the Al content shows higher hardness and heat resistance more excellently. Since the Ti content is relatively higher in the Ti highest content portion compared to the conventional (Ti, Al, Zr) N layer, the Ti highest content portion has higher strength and toughness. Since the interval between the highest Ti content points is extremely small, the layer as a whole has more excellent strength and toughness, and excellent high-temperature hardness and heat resistance. The coated carbide tool composed of the Al—Ti, Zr) N layer, together with the effect of improving the high-temperature strength provided by the Zr component, enables cutting of various steels and cast irons, particularly with high heat generation and high mechanical strength. Opposition The associated high speed when conducted in heavy cutting conditions even without the occurrence of chipping in the hard coating layer, to become to exert excellent wear resistance.
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 a hard coating layer composed of an (Al-Ti, Zr) N layer is physically formed on the surface of a super hard substrate at a total average layer thickness of 1 to 15 µm. In coated carbide tools made by evaporation,
In the hard coating layer, the Al maximum content point and the Ti maximum content point alternately and repeatedly exist at predetermined intervals along the thickness direction, and the Al maximum content point and the Ti maximum content point, Al and Ti contents have a component concentration distribution structure in which each of the components continuously changes from the highest content point to the highest Al content point,
Furthermore, the Al highest content point, the composition _{_{formula: (Al 1- (X + Y}} ) Ti X Zr Y) N ( provided that an atomic ratio, X is 0.05 to 0.30, Y is from 0.01 to 0. 15),
The Ti maximum content point, composition _{_{formula: (Ti 1- (Z + Y}} ) Al Z Zr Y) N ( provided that an atomic ratio, Z is 0.10 to 0.35, Y is a 0.01-0.15 Show),
Is satisfied, and the interval between the adjacent Al maximum content points and Ti maximum content points is 0.01 to 0.1 μm,
The present invention is characterized by a coated carbide tool in which a hard coating layer exhibits excellent wear resistance under high-speed heavy cutting conditions.
[0009]
Next, the reason why the configuration of the hard coating layer constituting the coated carbide tool of the present invention is limited as described above will be described.
(A) Composition of Al maximum content point The Al component at the Al maximum content point of the (Al-Ti, Zr) N layer improves high-temperature hardness and heat resistance, and the Ti component improves strength and toughness. The Zr component has an effect of improving the high-temperature strength. Therefore, the higher the content ratio of the Al component, the higher the high-temperature hardness and heat resistance. However, when the X value indicating the ratio of Ti is less than 0.05 in the ratio (atomic ratio) to the total amount of Al and Zr, the ratio of Al increases relatively. Even if the highest Ti content points having high strength and high toughness are 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, while the proportion of the Ti component X value indicating If it exceeds 0.30, the proportion of Al becomes relatively small, and it becomes impossible to secure desired excellent high-temperature hardness and heat resistance. If the ratio (atomic ratio) to the total amount of Al and Ti is less than 0.01, the desired high-temperature strength improving effect cannot be obtained, and if the Y value exceeds 0.15, the strength and toughness rapidly decrease. Therefore, the X value was set to 0.05 to 0.30 and the Y value was set to 0.01 to 0.15.
[0010]
(B) Composition of the highest Ti content point As described above, the highest Al content point has much higher high-temperature hardness and heat resistance, but is inferior in strength and toughness. For the purpose of compensating for the above, the highest Ti content point, which has a high Ti content ratio and thereby has high strength and high toughness, is alternately interposed in the thickness direction, and therefore, the Z value indicating the Al content is Ti When the ratio (atomic ratio) of the total amount of Zr and Zr exceeds 0.35, the ratio of Al becomes relatively large, and it is impossible to secure desired excellent strength and toughness. If the value is also less than 0.10, the proportion of Ti becomes relatively too large, so that the desired high-temperature hardness and heat resistance at the highest Ti content point cannot be ensured, which causes wear promotion. From the Z value Are as hereinbefore defined and .10～0.35 and Y value indicating a ratio of Zr components was determined as 0.01 to 0.15 for the same reason as in Al highest content point of the.
[0011]
(C) Interval between the highest Al content point and the highest Ti content point If the interval 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 more excellent strength and strength. If the spacing exceeds 0.1 μm, the disadvantages of the respective points, ie, if the Al content is the highest, the strength and toughness are insufficient, and the Ti is the highest. If the content point, high-temperature hardness and insufficient heat resistance locally appear in the layer, and as a result, chipping is likely to occur on the cutting edge or wear progress is promoted, so that the interval is reduced. It was determined as 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 secured, while if the average layer thickness exceeds 15 μm, chipping is likely to occur. Therefore, the average layer thickness was determined to be 1 to 15 μm.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, the coated cemented carbide tool of the present invention will be specifically described with reference to examples.
(Example 1)
As raw material powders, WC powder, TiC powder, VC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, and Co powder each having an average particle diameter of 1 to 3 μm were prepared. The mixture was wet-mixed in a ball mill for 60 hours, dried, and then pressed into a green compact at a pressure of 100 MPa, and the green compact was heated to 1405 ° C. for 1 hour in a vacuum of 6 Pa. Sintering is performed under the conditions of holding, and after sintering, the cutting edge portion is subjected to honing processing of R: 0.03, and a carbide substrate A1 to A10 made of a WC-based cemented carbide having a tip shape of ISO standard CNMG120412. Was formed.
[0014]
Further, as raw material powder, TiCN (TiC / TiN = 50/50 by weight) powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC powder each having an average particle diameter of 0.5 to 2 μm , Co powder, and Ni powder were prepared, and these raw material powders were blended in the composition shown in Table 2, wet-mixed for 72 hours in a ball mill, dried, and then pressed into a green compact at a pressure of 100 MPa. The green compact was sintered in a nitrogen atmosphere of 2 kPa at a temperature of 1500 ° C. for 1 hour, and after sintering, the cutting edge portion was subjected to a honing process of R: 0.03 to conform to ISO standard CNMG120412. Carbide bases B1 to B6 made of TiCN-based cermet having the chip shape described above were formed.
[0015]
Then, each of the above-mentioned super-hard substrates A1 to A10 and B1 to B6 is ultrasonically cleaned in acetone and dried, and is placed on a rotary table in an arc ion plating apparatus shown in FIG. Along the way, one side cathode electrode (evaporation source) is used as the Ti-Al-Zr alloy for forming the highest Ti content point having various component compositions, and the other side cathode electrode (evaporation source) is used as various components. The Al-Ti-Zr alloy for forming the highest Al content point having the composition is disposed to face the rotary table, and metal Ti for bombarding is also mounted. First, the inside of the apparatus is evacuated to 0.5 Pa or less. While maintaining the vacuum, the inside of the apparatus was heated to 500 ° C. by a heater, and then a DC bias voltage of −1000 V was applied to the super-hard substrate rotating while rotating on the rotary table. A current of 100 A is caused to flow between the metal Ti of the anode and the anode to generate an arc discharge, thereby cleaning the surface of the cemented carbide substrate with Ti bombardment, and then introducing nitrogen gas as a reaction gas into the apparatus at 3 Pa. A DC bias voltage of -30 V is applied to the superhard substrate rotating while rotating on the rotary table, and the respective cathode electrodes (the Ti-Al-Zr alloy for forming the highest Ti content point) are rotated. And an Al-Ti-Zr alloy for forming the highest Al content point) and a current of 140 A was applied between the anode electrode and an arc discharge to generate an arc discharge. , 4 where the Al maximum content point and the Ti maximum content point of the target composition are alternately present at the same target intervals shown in Tables 3 and 4, and A target overall layer having a component concentration distribution structure in which the Al and Ti contents continuously change from the Ti maximum content point to the Al maximum content point from the Ti maximum content point, and also shown in Tables 3 and 4 By depositing a thick hard coating layer, throw-away chips 1 to 16 made of the surface-coated cemented carbide of the present invention (hereinafter, referred to as the coated carbide chips of the present invention) as the coated carbide tools of the present invention were manufactured.
[0016]
For the purpose of comparison, these super-hard substrates A1 to A10 and B1 to B6 were ultrasonically cleaned in acetone, dried, and charged into a usual arc ion plating apparatus shown in FIG. A Ti—Al—Zr alloy having various component compositions is mounted as a cathode electrode (evaporation source), and a metal Ti for bombarding is further mounted. First, the inside of the apparatus is evacuated to a vacuum of 0.5 Pa or less. After the inside of the apparatus was heated to 400 ° C. with the heater while holding, a DC bias voltage of −1000 V was applied to the superhard substrate, and a current of 100 A was passed between the metal Ti of the cathode electrode and the anode electrode. Arc discharge was generated, and the surface of the super-hard substrate was cleaned by Ti bombardment. Then, nitrogen gas was introduced into the apparatus as a reaction gas to make a reaction atmosphere of 2 Pa. A DC bias voltage of -80 V is applied to the substrate, an arc discharge is generated by flowing a current of 90 A between the Ti-Al-Zr alloy of the cathode electrode and the anode electrode, and thereby the carbide substrates A1 to A10 and From the (Ti, Al, Zr) N layer having the target composition and the target layer thickness shown in Tables 5 and 6, and having substantially no composition change along the layer thickness direction, on each surface of B1 to B6 By depositing such a hard coating layer, throw-away tips made of conventional surface-coated cemented carbide (hereinafter referred to as conventional coated cemented carbide tips) 1 to 16 as conventional coated cemented carbide tools were respectively manufactured.
[0017]
Next, with respect to the above-mentioned coated carbide tips 1 to 16 of the present invention and conventional coated carbide tips 1 to 16, in a state where they were screwed to the tip of a tool steel tool with a fixing jig,
Work material: JIS S20C round bar,
Cutting speed: 300 m / min. ,
Cut: 5.5 mm,
Feed: 0.15 mm / rev. ,
Cutting time: 5 minutes,
Dry continuous high-speed cutting test of carbon steel under the following conditions:
Work material: Round bar with four vertical grooves at equal intervals in the longitudinal direction of JIS SS400
Cutting speed: 300 m / min. ,
Notch: 1.8 mm,
Feed: 0.5 mm / rev. ,
Cutting time: 5 minutes,
Intermittent high-speed high-feed cutting test of mild steel under the following conditions:
Work material: JIS FC200 round bar,
Cutting speed: 330 m / min. ,
Cut: 6mm,
Feed: 0.16 mm / rev. ,
Cutting time: 5 minutes,
A dry continuous high-speed, high-cut cutting test was performed on cast iron under the following conditions, and the flank wear width of the cutting edge was measured in each cutting test. Table 7 shows the measurement results.
[0018]
[Table 1]

[0019]
[Table 2]

[0020]
[Table 3]

[0021]
[Table 4]

[0022]
[Table 5]

[0023]
[Table 6]

[0024]
[Table 7]

[0025]
(Example 2)
As raw material powders, medium coarse WC powder having an average particle size of 5.5 μm, fine WC powder of 0.8 μm, TaC powder of 1.3 μm, NbC powder of 1.2 μm, and Zr of 1.2 μm 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 were prepared. Each was blended in the blending composition shown in Table 8, and further added with wax, ball-milled in acetone for 24 hours, dried under reduced pressure, and then pressed into various compacts of a predetermined shape at a pressure of 60 MPa. The green compact is heated in a vacuum atmosphere of 6 Pa at a heating rate of 7 ° C./min to a predetermined temperature in the range of 1370 to 1470 ° C., and is kept at this temperature for 1 hour, and then fired under furnace cooling conditions. Tie, 8mm, 13mm and 26m in diameter The three types of round bar sintered bodies for forming a cemented carbide substrate were formed, and the three types of round bar sintered bodies were further subjected to grinding processing in a combination shown in Table 8 to obtain a diameter of the cutting edge portion × Carbide substrates (end mills) C-1 to C-8 each having dimensions of 6 mm × 13 mm, 10 mm × 22 mm, and 20 mm × 45 mm, and each having a four-flute square shape with a twist angle of 30 °. Each was manufactured.
[0026]
Then, these super-hard substrates (end mills) C-1 to C-8 were ultrasonically cleaned in acetone, dried, and charged into an arc ion plating apparatus also shown in FIG. Under the same conditions as in Example 1, Al maximum content points and Ti maximum content points of the target compositions shown in Table 9 alternately exist along the thickness direction alternately at the target intervals shown in Table 9 as well, and It has a component concentration distribution structure in which the Al and Ti contents continuously change from the highest Al content point to the highest Ti content point, and from the highest Ti content point to the highest Al content point, and are also shown in Table 9. By depositing a hard coating layer having a target overall layer thickness, end mills (hereinafter, referred to as coated carbide end mills) 1 to 8 of the surface coated cemented carbide alloy of the present invention as coated carbide tools of the present invention were produced, respectively. .
[0027]
For the purpose of comparison, the above-mentioned ultra-hard substrates (end mills) C-1 to C-8 were ultrasonically cleaned in acetone and dried, and then a normal arc ion plating apparatus also shown in FIG. Under the same conditions as in Example 1 above, having the target composition and target layer thickness shown in Table 10, and having substantially no composition change along the layer thickness direction (Ti, Al, Zr). 3) End mills made of conventional surface-coated cemented carbide (hereinafter referred to as conventional coated carbide end mills) 1 to 8 as conventional coated cemented carbide tools were produced by depositing a hard coating layer composed of an N layer.
[0028]
Next, among the coated carbide end mills 1 to 8 of the present invention and the conventional coated carbide end mills 1 to 8, of the coated carbide end mills 1 to 3 and the coated carbide end mills 1 to 3 of the present invention,
Work material: Plane dimensions: 100 mm x 250 mm, thickness: 50 mm JIS / FC200 plate,
Cutting speed: 330 m / min. ,
Axial cut: 10 mm
Radial cut: 2mm,
Table feed: 210 mm / min,
For the wet-type high-speed high-cut side cutting test of cast iron under the conditions of
Work material: Plane dimensions: 100 mm x 250 mm, thickness: 50 mm, JIS SS400 plate,
Cutting speed: 310 m / min. ,
Axial cut: 18 mm,
Radial cut: 3.2 mm,
Table feed: 190 mm / min.
The wet-type high-speed high-cut side-cutting test of mild steel under the conditions described above, the coated carbide end mills 7 and 8 of the present invention, and
Work material: Plane dimensions: 100 mm x 250 mm, thickness: 50 mm, JIS S20C plate,
Cutting speed: 310 m / min. ,
Axial cut: 40 mm,
Radial cut: 6.2 mm,
Table feed: 100 mm / min,
Wet high-speed, high-cut side-cutting tests of carbon steel were conducted under the conditions described above, and the flank wear width of the outer peripheral edge of the cutting edge was a measure of the service life 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 9 and 10, respectively.
[0029]
[Table 8]

[0030]
[Table 9]

[0031]
[Table 10]

[0032]
(Example 3)
The diameters produced in Example 2 were 8 mm (for forming the super-hard substrates C-1 to C-3), 13 mm (for forming the super-hard substrates C-4 to C-6), and 26 mm (for the super-hard substrates C-). 7, for forming C-8), the diameter x length of the groove forming portion was 4 mm x 13 mm (by grinding) from the three types of round rod sintered bodies by grinding. Carbide substrates D-1 to D-3), dimensions of 8 mm x 22 mm (carbide substrates D-4 to D-6), and 16 mm x 45 mm (carbide substrates D-7 and D-8), and any of them Carbide substrates (drills) D-1 to D-8 each having a two-blade shape with a twist angle of 30 degrees were manufactured.
[0033]
Next, the cutting blades of the super hard substrates (drills) D-1 to D-8 are honed, ultrasonically cleaned in acetone, and dried, and then the arc ion plating apparatus shown in FIG. Under the same conditions as in Example 1 described above, and the Al maximum content points and the Ti maximum content points of the target compositions shown in Table 11 are alternately arranged along the layer thickness direction at the target intervals also shown in Table 11 Having a component concentration distribution structure in which the Al and Ti contents continuously change from the Al highest content point to the Ti highest content point, and the Ti highest content point to the Al highest content point, respectively, Further, by depositing a hard coating layer having a target total layer thickness also shown in Table 11, a drill 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 coated carbide drill of the present invention). 1 to 8 Re respectively were produced.
[0034]
Also, for comparison purposes, the cutting edges of the above-mentioned carbide substrates (drills) D-1 to D-8 are honed, ultrasonically cleaned in acetone, and dried, and are also shown in FIG. It was charged in a normal arc ion plating apparatus, and had the target composition and the target layer thickness shown in Table 12 under the same conditions as in Example 1 above, and the composition change substantially along the layer thickness direction. By depositing a hard coating layer composed of a non-coated (Ti, Al, Zr) N layer, a conventional surface coated cemented carbide drill as a conventionally coated cemented carbide tool (hereinafter referred to as a conventionally coated cemented carbide drill) 1-8 Was manufactured respectively.
[0035]
Next, of the coated carbide drills 1 to 8 of the present invention and the coated carbide drills 1 to 8 of the related art, the coated carbide drills 1 to 3 of the present invention and the covered carbide drills 1 to 3 of the present invention are:
Work material: Plane dimensions: 100 mm x 250 mm, thickness: 50 mm, JIS SS400 plate,
Cutting speed: 200 m / min. ,
Feed: 0.45 mm / rev,
Hole depth: 10mm,
For the wet-type high-speed and high-feed drilling cutting test of mild steel under the conditions of
Work material: Plane dimensions: 100 mm x 250 mm, thickness: 50 mm, JIS S20C plate,
Cutting speed: 210 m / min. ,
Feed: 0.45 mm / rev,
Hole depth: 15mm,
For the wet-type high-speed and high-feed drilling cutting test of carbon steel under the conditions described below, the coated carbide drills 7 and 8 of the present invention and the conventionally coated
Work material: Plane dimensions: 100 mm x 250 mm, thickness: 50 mm JIS / FC200 plate,
Cutting speed: 230 m / min. ,
Feed: 0.6 mm / rev,
Hole depth: 30mm,
Welding high-speed, high-feed drilling test for cast iron under the conditions described above, and in all wet drilling tests (using water-soluble cutting oil), the flank wear width of the tip cutting edge reaches 0.3 mm. Was measured. The measurement results are shown in Tables 11 and 12, respectively.
[0036]
[Table 11]

[0037]
[Table 12]

[0038]
The resulting coated carbide tips 1 to 16, the coated carbide end mills 1 to 8 as the resulting coated carbide tools of the present invention, and the hard coating layers constituting the coated carbide drills 1 to 8 of the present invention. Composition of Al maximum content point and Ti maximum content point, and hard coating of conventional coated carbide tips 1-16, conventional coated carbide end mills 1-8, and conventional coated carbide drills 1-8 as conventional coated carbide tools When the composition of the layers was measured using an Auger spectrometer, they each showed substantially the same composition as the target composition.
Further, the interval between the highest Al content point and the highest Ti content point in the hard coating layer of the coated carbide tool of the present invention, and the total layer thickness thereof, and the thickness of the hard coating layer of the conventional coated carbide tool, When the cross section was measured using a scanning electron microscope, all the values showed substantially the same value as the target value.
[0039]
【The invention's effect】
From the results shown in Tables 3 to 12, the hard coating layer has, in the thickness direction, the highest Al content point having relatively higher high-temperature hardness and heat resistance, and the highest Ti content having the same relatively high strength and toughness. And the content points are alternately and repeatedly present at predetermined intervals, and the Al content and the Ti content are continuously changed from the Al highest content point to the Ti highest content point and the Ti highest content point to the Al highest content point, respectively. Any of the coated carbide tools of the present invention having a variable component concentration distribution structure, in combination with the fact that the hard coating layer has excellent high-temperature strength due to the inclusion of the Zr component, can cut various types of steel and cast iron. Even when processing is performed under high speed conditions with high temperature generation and heavy cutting conditions such as high cutting and high feed with high mechanical impact, the hard coating layer has excellent wear resistance without chipping. On the other hand, in the conventional coated cemented carbide tool in which the hard coating layer is composed of a (Ti, Al, Zr) N layer having substantially no composition change along the thickness direction, the hard coating layer is subjected to the above-mentioned high-speed heavy cutting conditions. Because of the lack of high-temperature hardness and heat resistance of the hard coating layer, as well as the lack of strength and toughness, wear progresses quickly, and chipping is likely to occur. is there.
As described above, the coated cemented carbide tool of the present invention can be used not only for cutting under normal conditions, but also for cutting various kinds of steel and cast iron, etc., at high speed heavy cutting accompanied by high heat generation and high mechanical impact. Even under the conditions, since it exhibits excellent abrasion resistance without occurrence of chipping, it can sufficiently cope with labor-saving and energy-saving of the cutting work, and further, cost reduction.
[Brief description of the drawings]
FIG. 1 shows an arc ion plating apparatus used for forming a hard coating layer constituting a coated carbide tool of the present invention, wherein (a) is a schematic plan view and (b) is a schematic front view.
FIG. 2 is a schematic explanatory view of a conventional arc ion plating apparatus used for forming a hard coating layer constituting a conventional coated carbide tool.

Claims

Surface coating formed by physical vapor deposition of a hard coating layer composed of a composite nitride layer of Al, Ti and Zr on the surface of a tungsten carbide-based cemented carbide substrate or a titanium carbonitride-based cermet substrate with a total average layer thickness of 1 to 15 μm. In cemented carbide cutting tools,
In the hard coating layer, the highest Al content point and the highest Ti content point alternately and repeatedly exist at predetermined intervals along the layer thickness direction, and the highest Al content point and the highest Ti content point, Al and Ti contents have a component concentration distribution structure in which each of the components continuously changes from the highest content point to the highest Al content point,
Furthermore, the Al highest content point, the composition _{_{formula: (Al 1- (X + Y}} ) Ti X Zr Y) N ( provided that an atomic ratio, X is 0.05 to 0.30, Y is from 0.01 to 0. 15),
The Ti maximum content point, composition _{_{formula: (Ti 1- (Z + Y}} ) Al Z Zr Y) N ( provided that an atomic ratio, Z is 0.10 to 0.35, Y is a 0.01-0.15 Show),
And the distance between the adjacent Al maximum content point and Ti maximum content point is 0.01 to 0.1 μm,
Surface coated cemented carbide cutting tool with a hard coating layer that exhibits excellent wear resistance under high speed heavy cutting conditions.