JP2004136384A

JP2004136384A - Surface-coated cermet cutting tool having hard coating layer exhibiting excellent wear resistance under high-speed heavy cutting condition

Info

Publication number: JP2004136384A
Application number: JP2002301488A
Authority: JP
Inventors: Koichi Maeda; 前田　浩一; Akihiro Kondou; 近藤　暁裕; Yusuke Tanaka; 田中　裕介
Original assignee: Mitsubishi Materials Corp; Mitsubishi Materials Kobe Tools Corp
Current assignee: Mitsubishi Materials Corp; Mitsubishi Materials Kobe Tools Corp
Priority date: 2002-10-16
Filing date: 2002-10-16
Publication date: 2004-05-13
Anticipated expiration: 2022-10-16
Also published as: JP4048365B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-coated cermet cutting tool which has a hard coating layer exhibiting an excellent wear resistance under a high-speed heavy cutting condition. <P>SOLUTION: The coated cermet tool is formed of a cermet substrate and the coating layer made of a composite nitride containing Al, Ti, and B, applied to a surface of the substrate. The hard coating layer has a component concentration distribution structure, wherein maximum Al content points and maximum Ti content points are alternately disposed at predetermined intervals in a layer thickness direction, and wherein the Al content and the Ti content are sequentially varied from the maximum Al content point to the maximum Ti content point and vice versa. Further, the Al maximum content point and the Ti maximum content point satisfy the following chemical composition formulas: (Al<SB>1-(X+Z)</SB>Ti<SB>X</SB>B<SB>Z</SB>)N (where X represents a numerical value in the range of 0.05 to 0.25, and Z in the range of 0.01 to 0.10 by atomic ratios), (Ti<SB>1-(Y+Z)</SB>Al<SB>Y</SB>B<SB>Z</SB>)N (where Y represents a numerical value in the range of 0.05 to 0.25, and Z in the range of 0.01 to 0.10). Herein an interval between the adjacent maximum Al content point and the maximum Ti content point is set in the range of 0.01 to 0.1 μm. <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サーメット製切削工具（以下、被覆サーメット工具という）に関するものである。
【０００２】
【従来の技術】
一般に、被覆サーメット工具には、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、被覆サーメット工具として、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）基サーメットで構成されたサーメット基体の表面に、組成式：（Ｔｉ_{１−（Ｙ＋Ｚ）}Ａｌ_ＹＢ_Ｚ）Ｎ（ただし、原子比で、Ｙは０．４０〜０．６０、Ｚは０．０１〜０．１０を示す）を満足するＴｉとＡｌとＢの複合窒化物［以下、（Ｔｉ，Ａｌ，Ｂ）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サーメット工具がが知られており、かつ前記被覆サーメット工具の硬質被覆層である（Ｔｉ，Ａｌ，Ｂ）Ｎ層が、構成成分であるＡｌによって高温硬さと耐熱性、同Ｔｉによって強度を具備し、さらに同Ｂによる一段の高温硬さ向上効果と相俟って、これを各種の鋼や鋳鉄などの連続切削や断続切削加工に用いた場合にすぐれた切削性能を発揮することも知られている（例えば特許文献１参照）。
【０００４】
さらに、上記の被覆サーメット工具が、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サーメット基体を装入し、ヒータで装置内を、例えば５００℃の温度に加熱した状態で、アノード電極と所定組成を有するＴｉ−Ａｌ−Ｂ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、一方上記サーメット基体には、例えば−１００Ｖのバイアス電圧を印加した条件で、前記サーメット基体の表面に、上記（Ｔｉ，Ａｌ，Ｂ）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（例えば特許文献１参照）。
【０００５】
【特許文献１】
特許第２７９３６９６号明細書
【０００６】
【発明が解決しようとする課題】
近年の切削加工装置の高性能化はめざましく、一方で切削加工に対する省力化および省エネ化、さらに低コスト化の要求も強く、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、上記の従来被覆サーメット工具においては、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。
【０００７】
【課題を解決するための手段】
そこで、本発明者等は、上述のような観点から、特に高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サーメット工具を開発すべく、上記の従来被覆サーメット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サーメット工具を構成する（Ｔｉ，Ａｌ，Ｂ）Ｎ層は、層厚全体に亘って実質的に均一な組成を有し、したがって均質な高温硬さと耐熱性、さらに強度を有するが、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サーメット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−Ｂ合金、他方側に相対的にＴｉ含有量の高いＴｉ−Ａｌ−Ｂ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上の中心軸から半径方向に所定距離離れた位置にテーブル外周部に沿って複数のサーメット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サーメット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、前記サーメット基体の表面にＡｌとＴｉとＢの複合窒化物［以下、（Ａｌ−Ｔｉ，Ｂ）Ｎで示す］層を形成すると、この結果の（Ａｌ−Ｔｉ，Ｂ）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サーメット基体が上記の一方側の相対的にＡｌ含有量の高いＡｌ−Ｔｉ−Ｂ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、また前記サーメット基体が上記の他方側の相対的にＴｉ含有量の高いＴｉ−Ａｌ−Ｂ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層厚方向にそって前記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。
【０００８】
（ｂ）上記（ａ）の繰り返し連続変化成分濃度分布構造の（Ａｌ−Ｔｉ，Ｂ）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−Ｂ合金におけるＡｌ含有量を上記の従来Ｔｉ−Ａｌ−Ｂ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−Ｂ合金におけるＡｌ含有量を上記の従来Ｔｉ−Ａｌ−Ｂ合金のＡｌ含有量に比して相対的に低いものとする共に、サーメット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＋Ｚ）}Ｔｉ_ＸＢ_Ｚ）Ｎ（ただし、原子比で、Ｘは０．０５〜０．２５、Ｚは０．０１〜０．１０を示す）、
上記Ｔｉ最高含有点が、組成式：（Ｔｉ_{１−（Ｙ＋Ｚ）}Ａｌ_ＹＢ_Ｚ）Ｎ（ただし、原子比で、Ｙは０．０５〜０．２５、Ｚは０．０１〜０．１０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，Ｂ）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，Ｂ）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高強度を保持した状態で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，Ｂ）Ｎ層からなる被覆サーメット工具は、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。
【０００９】
この発明は、上記の研究結果に基づいてなされたものであって、サーメット基体の表面に、（Ａｌ−Ｔｉ，Ｂ）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サーメット工具において、
上記硬質被覆層が、層厚方向にそって、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＋Ｚ）}Ｔｉ_ＸＢ_Ｚ）Ｎ（ただし、原子比で、Ｘは０．０５〜０．２５、Ｚは０．０１〜０．１０を示す）、
上記Ｔｉ最高含有点が、組成式：（Ｔｉ_{１−（Ｙ＋Ｚ）}Ａｌ_ＹＢ_Ｚ）Ｎ（ただし、原子比で、Ｙは０．０５〜０．２５、Ｚは０．０１〜０．１０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サーメット工具に特徴を有するものである。
【００１０】
つぎに、この発明の被覆サーメット工具において、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
硬質被覆層である（Ａｌ−Ｔｉ，Ｂ）Ｎ層のＡｌ最高含有点におけるＡｌ成分は、高温硬さと耐熱性を向上させ、同Ｔｉ成分は強度を向上させ、さらに同Ｂ成分は一段と高温硬さを向上させる作用があり、したがってＡｌ成分およびＢ成分の含有割合が高くなればなるほど高温硬さと耐熱性は向上し、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Ｂ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０．２５を越えると、相対的にＡｌの割合が少なくなることから、高温硬さと耐熱性の低下は避けられず、これが摩耗促進の原因となり、またＢ成分の割合を示すＺ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硬さ向上効果が得られず、さらに同Ｚ値が０．１０を超えると、チッピングなどの発生原因となる強度低下が起るようになることから、Ｘ値を０．０５〜０．２５、Ｚ値を０．０１〜０．１０とそれぞれ定めた。
【００１１】
（ｂ）Ｔｉ最高含有点の組成
上記の通りＡｌ最高含有点は高温硬さと耐熱性のすぐれたものであるが、反面強度の劣るものであるため、このＡｌ最高含有点の強度不足を補う目的で、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Ｙ値がＴｉとＢの合量に占める割合（原子比）で０．２５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を確保することができず、一方同Ｙ値が同じく０．０５未満になると、相対的にＴｉの割合が多くなり過ぎて、Ｔｉ最高含有点における高温硬さと耐熱性が急激に低下し、これが摩耗促進の原因となることから、Ｙ値を０．０５〜０．２５と定めたものであり、またＢ成分の割合を示すＺ値は上記のＡｌ最高含有点におけると同じ理由で０．０１〜０．１０と定めた。
【００１２】
（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、この結果硬質被覆層に所望の高強度、さらに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。
【００１３】
（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。
【００１４】
【発明の実施の形態】
つぎに、この発明の被覆サーメット工具を実施例により具体的に説明する。
（実施例１）
原料粉末として、いずれも１〜３μｍの平均粒径を有するＷＣ粉末、ＴｉＣ粉末、ＶＣ粉末、ＴａＣ粉末、ＮｂＣ粉末、Ｃｒ_３Ｃ_２粉末、およびＣｏ粉末を用意し、これら原料粉末を、表１に示される配合組成に配合し、ボールミルで７２時間湿式混合し、乾燥した後、１００ＭＰａ　の圧力で圧粉体にプレス成形し、この圧粉体を６Ｐａの真空中、温度：１４００℃に１時間保持の条件で焼結し、焼結後、切刃部分にＲ：０．０３のホーニング加工を施してＩＳＯ規格・ＣＮＭＧ１２０４０８のチップ形状をもったＷＣ基超硬合金製のサーメット基体Ａ１〜Ａ１０を形成した。
【００１５】
また、原料粉末として、いずれも０．５〜２μｍの平均粒径を有するＴｉＣＮ（重量比でＴｉＣ／ＴｉＮ＝５０／５０）粉末、Ｍｏ_２Ｃ粉末、ＺｒＣ粉末、ＮｂＣ粉末、ＴａＣ粉末、ＷＣ粉末、Ｃｏ粉末、およびＮｉ粉末を用意し、これら原料粉末を、表２に示される配合組成に配合し、ボールミルで２４時間湿式混合し、乾燥した後、１００ＭＰａの圧力で圧粉体にプレス成形し、この圧粉体を２ｋＰａの窒素雰囲気中、温度：１５００℃に１時間保持の条件で焼結し、焼結後、切刃部分にＲ：０．０３のホーニング加工を施してＩＳＯ規格・ＣＮＭＧ１２０４０８のチップ形状をもったＴｉＣＮ系サーメット製のサーメット基体Ｂ１〜Ｂ６を形成した。
【００１６】
ついで、上記のサーメット基体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の中心軸から半径方向に所定距離離れた位置にテーブル外周部にそってリング状に装着し、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−Ｂ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−Ｂ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サーメット基体に−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、もってサーメット基体表面をＴｉボンバート洗浄し、ついで装置内に反応ガスとして窒素ガスを導入して２Ｐａの反応雰囲気とすると共に、前記回転テーブル上で自転しながら回転するサーメット基体に−１００Ｖの直流バイアス電圧を印加し、かつそれぞれのカソード電極（前記Ｔｉ最高含有点形成用Ｔｉ−Ａｌ−Ｂ合金およびＡｌ最高含有点形成用Ａｌ−Ｔｉ−Ｂ合金）とアノード電極との間に１００Ａの電流を流してアーク放電を発生させ、もって前記サーメット基体の表面に、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、本発明被覆サーメット工具としての本発明表面被覆サーメット製スローアウエイチップ（以下、本発明被覆チップと云う）１〜１６をそれぞれ製造した。
【００１７】
また、比較の目的で、これらサーメット基体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−Ｂ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５００℃に加熱した後、前記サーメット基体に−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、もってサーメット基体表面を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、サーメット基体に−１００Ｖの直流バイアス電圧を印加し、前記カソード電極のＴｉ−Ａｌ−Ｂ合金とアノード電極との間に１００Ａの電流を流してアーク放電を発生させ、もって前記サーメット基体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，Ｂ）Ｎ層からなる硬質被覆層を蒸着することにより、従来被覆サーメット工具としての従来表面被覆サーメット製スローアウエイチップ（以下、従来被覆チップと云う）１〜１６をそれぞれ製造した。
【００１８】
つぎに、上記の各種の被覆チップを、いずれも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、本発明被覆チップ１〜１０および従来被覆チップ１〜１０については、
被削材：ＪＩＳ・ＦＣ２５０の丸棒、
切削速度：４５０ｍ／ｍｉｎ．、
切り込み：４ｍｍ、
送り：０．３ｍｍ／ｒｅｖ．、
切削時間：１５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、
被削材：ＪＩＳ・ＳＮＣＭ４３９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：４．５ｍｍ、
送り：０．２ｍｍ／ｒｅｖ．、
切削時間：５分、
の条件での合金鋼の乾式断続高速高切り込み切削加工試験、
被削材：ＪＩＳ・Ｓ５０Ｃの丸棒、
切削速度：４００ｍ／ｍｉｎ．、
切り込み：１．５ｍｍ、
送り：０．６ｍｍ／ｒｅｖ．、
切削時間：１０分、
の条件での炭素鋼の乾式連続高速高送り切削加工試験を行なった。
【００１９】
さらに、本発明被覆チップ１１〜１６および従来被覆チップ１１〜１６については、
被削材：ＪＩＳ・ＦＣ３００の丸棒、
切削速度：５００ｍ／ｍｉｎ．、
切り込み：４．５ｍｍ、
送り：０．４ｍｍ／ｒｅｖ．、
切削時間：１５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、
被削材：ＪＩＳ・ＳＣＭ４３５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：４ｍｍ、
送り：０．４ｍｍ／ｒｅｖ．、
切削時間：５分、
の条件での合金鋼の乾式断続高速高切り込み切削加工試験、
被削材：ＪＩＳ・Ｓ５５Ｃの丸棒、
切削速度：３５０ｍ／ｍｉｎ．、
切り込み：２ｍｍ、
送り：０．７ｍｍ／ｒｅｖ．、
切削時間：１０分、
の条件での炭素鋼の乾式連続高速高送り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。
【００２０】
【表１】

【００２１】
【表２】

【００２２】
【表３】

【００２３】
【表４】

【００２４】
【表５】

【００２５】
【表６】

【００２６】
【表７】

【００２７】
（実施例２）
原料粉末として、平均粒径：５．５μｍを有する中粗粒ＷＣ粉末、同０．８μｍの微粒ＷＣ粉末、同１．３μｍのＴａＣ粉末、同１．２μｍのＮｂＣ粉末、同１．２μｍのＺｒＣ粉末、同２．３μｍのＣｒ_３Ｃ_２粉末、同１．５μｍのＶＣ粉末、同１．０μｍの（Ｔｉ，Ｗ）Ｃ粉末、および同１．８μｍのＣｏ粉末を用意し、これら原料粉末をそれぞれ表８に示される配合組成に配合し、さらにワックスを加えてアセトン中で２４時間ボールミル混合し、減圧乾燥した後、１００ＭＰａの圧力で所定形状の各種の圧粉体にプレス成形し、これらの圧粉体を、６Ｐａの真空雰囲気中、７℃／分の昇温速度で１３７０〜１４７０℃の範囲内の所定の温度に昇温し、この温度に１時間保持後、炉冷の条件で焼結して、直径が８ｍｍ、１３ｍｍ、および２６ｍｍの３種のサーメット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枚刃スクエアの形状をもったサーメット基体（エンドミル）Ｃ−１〜Ｃ−８をそれぞれ製造した。
【００２８】
ついで、これらのサーメット基体（エンドミル）Ｃ−１〜Ｃ−８を、アセトン中で超音波洗浄し、乾燥した状態で、同じく図１に示されるアークイオンプレーティング装置に装入し、上記実施例１と同一の条件で、層厚方向に沿って表９に示される目標組成の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、本発明被覆サーメット工具としての本発明表面被覆サーメット製エンドミル（以下、本発明被覆エンドミルと云う）１〜８をそれぞれ製造した。
【００２９】
また、比較の目的で、上記のサーメット基体（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，Ｂ）Ｎ層からなる硬質被覆層を蒸着することにより、従来被覆サーメット工具としての従来表面被覆サーメット製エンドミル（以下、従来被覆エンドミルと云う）１〜８をそれぞれ製造した。
【００３０】
つぎに、上記本発明被覆エンドミル１〜８および従来被覆エンドミル１〜８のうち、本発明被覆エンドミル１〜３および従来被覆エンドミル１〜３については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・Ｓ４５Ｃの板材、
切削速度：２００ｍ／ｍｉｎ．、
溝深さ（切り込み）：１．５ｍｍ、
テーブル送り：１０００ｍｍ／分、
の条件での炭素鋼の乾式高速高送り溝切削加工試験、本発明被覆エンドミル４〜６および従来被覆エンドミル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：２５０ｍ／ｍｉｎ．、
溝深さ（切り込み）：５．５ｍｍ、
テーブル送り：１２００ｍｍ／分、
の条件での構造用鋼の乾式高速高切り込み溝切削加工試験、本発明被覆エンドミル７，８および従来被覆エンドミル７，８については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＳＫＤ６１の板材、
切削速度：１８０ｍ／ｍｉｎ．、
溝深さ（切り込み）：５ｍｍ、
テーブル送り：３００ｍｍ／分、
の条件での工具鋼の乾式高速高送り溝切削加工試験をそれぞれ行い、いずれの溝切削加工試験でも切刃部の外周刃の逃げ面摩耗幅が使用寿命の目安とされる０．１ｍｍに至るまでの切削溝長を測定した。この測定結果を表９、１０にそれぞれ示した。
【００３１】
【表８】

【００３２】
【表９】

【００３３】
【表１０】

【００３４】
（実施例３）
上記の実施例２で製造した直径が８ｍｍ（サーメット基体Ｃ−１〜Ｃ−３形成用）、１３ｍｍ（サーメット基体Ｃ−４〜Ｃ−６形成用）、および２６ｍｍ（サーメット基体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（サーメット基体Ｄ−１〜Ｄ−３）、８ｍｍ×２２ｍｍ（サーメット基体Ｄ−４〜Ｄ−６）、および１６ｍｍ×４５ｍｍ（サーメット基体Ｄ−７、Ｄ−８）の寸法、並びにいずれもねじれ角３０度の２枚刃形状をもったサーメット基体（ドリル）Ｄ−１〜Ｄ−８をそれぞれ製造した。
【００３５】
ついで、これらのサーメット基体（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、本発明被覆サーメット工具としての本発明表面被覆サーメット製ドリル（以下、本発明被覆ドリルと云う）１〜８をそれぞれ製造した。
【００３６】
また、比較の目的で、上記のサーメット基体（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，Ｂ）Ｎ層からなる硬質被覆層を蒸着することにより、従来被覆サーメット工具としての従来表面被覆サーメット製ドリル（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。
【００３７】
つぎに、上記本発明被覆ドリル１〜８および従来被覆ドリル１〜８のうち、本発明被覆ドリル１〜３および従来被覆ドリル１〜３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：２００ｍ／ｍｉｎ．、
送り：０．２ｍｍ／ｒｅｖ、
穴深さ：８ｍｍ、
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、本発明被覆ドリル４〜６および従来被覆ドリル４〜６については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＳＫＤ６１の板材、
切削速度：１６０ｍ／ｍｉｎ．、
送り：０．３ｍｍ／ｒｅｖ、
穴深さ：１６ｍｍ、
の条件での工具鋼の湿式高速高送り穴あけ切削加工試験、本発明被覆ドリル７，８および従来被覆ドリル７，８については、
被削材：平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・Ｓ５５Ｃの板材、
切削速度：１７５ｍ／ｍｉｎ．、
送り：０．４ｍｍ／ｒｅｖ、
穴深さ：３２ｍｍ、
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、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。
【００３８】
【表１１】

【００３９】
【表１２】

【００４０】
この結果得られた本発明被覆サーメット工具としての本発明被覆チップ１〜１６、本発明被覆エンドミル１〜８、および本発明被覆ドリル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、並びに従来被覆サーメット工具としての従来被覆チップ１〜１６、従来被覆エンドミル１〜８、および従来被覆ドリル１〜８の硬質被覆層について、厚さ方向に沿ってＡｌ、Ｔｉ、およびＢの含有量をオージェ分光分析装置を用いて測定したところ、本発明被覆サーメット工具の硬質被覆層では、Ａｌ最高含有点とＴｉ最高含有点とがそれぞれ目標値と実質的に同じ組成および間隔で交互に繰り返し存在し、かつ前記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成分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ことが確認され、また硬質被覆層の全体平均層厚も目標全体層厚と実質的に同じ値を示した。
一方前記従来被覆サーメット工具の硬質被覆層では厚さ方向に沿って組成変化が見られず、かつ目標組成と実質的に同じ組成および目標全体層厚と実質的に同じ全体平均層厚を示すことが確認された。
【００４１】
【発明の効果】
表３〜１２に示される結果から、硬質被覆層が層厚方向に、すぐれた高温硬さと耐熱性を有するＡｌ最高含有点と、高強度を有する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サーメット工具は、いずれも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、硬質被覆層が層厚方向に沿って実質的に組成変化のない（Ｔｉ，Ａｌ，Ｂ）Ｎ層からなる従来被覆サーメット工具においては、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、並びに強度不足が原因で、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、この発明の被覆サーメット工具は、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】この発明の被覆サーメット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】従来被覆サーメット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 therefore, can cut various steels and cast irons at high speeds, particularly with high heat generation, and with high mechanical impact. Surface-coated cermet cutting tool (hereinafter referred to as coated cermet tool) that shows excellent wear resistance without causing chipping (small chipping) in the hard coating layer when performed under heavy cutting conditions such as high cutting and high feed It is about).
[0002]
[Prior art]
In general, coated cermet tools include throw-away inserts that are detachably attached to the tip of a cutting tool for turning and planing of various materials such as steel and cast iron, and drills used for drilling and cutting. There is a solid type end mill used for face milling, grooving, shoulder processing, etc., and a throw that performs cutting similarly to the solid type end mill by detachably attaching the throw-away tip. Away end mill tools and the like are known.
[0003]
Further, as a coated cermet tool, the surface of a cermet substrate composed of tungsten carbide (hereinafter, referred to as WC) -based cemented carbide or titanium carbonitride (hereinafter, referred to as TiCN) -based cermet has a composition formula: (Ti ₁₋ A composite nitride of Ti, Al and B satisfying _{(Y + Z)} Al _Y B _Z ) N (where Y represents 0.40 to 0.60 and Z represents 0.01 to 0.10 in atomic ratio) There is known a coated cermet tool obtained by physically depositing a hard coating layer composed of [Ti (Al, B) N] layers with an average layer thickness of 1 to 15 μm. The (Ti, Al, B) N layer, which is a hard coating layer, has high-temperature hardness and heat resistance due to Al as a constituent component, has strength due to Ti, and is further combined with a further high-temperature hardness improvement effect due to B. What this means Exerting a cutting performance which is superior when used in continuous cutting or interrupted cutting such as iron are also known (for example, see Patent Document 1).
[0004]
Further, the above-mentioned coated cermet tool is, for example, the above-mentioned cermet substrate is charged into an arc ion plating apparatus which is one kind of physical vapor deposition apparatus schematically shown in FIG. An arc discharge is generated between the anode electrode and a cathode electrode (evaporation source) on which a Ti-Al-B alloy having a predetermined composition is set, for example, under the condition of a current of 90 A, while being heated to a temperature of ° 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, under the condition that a bias voltage of, for example, -100 V is applied to the cermet substrate, the (Ti) , Al, B) It is also known that it is manufactured by evaporating a hard coating layer composed of a N layer (for example, see Patent Document 1).
[0005]
[Patent Document 1]
Japanese Patent No. 2793696 Specification
[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 that cutting under heavy cutting conditions such as high feed is strongly required, but in the above-mentioned conventional coated cermet tools, there is no problem if this is used under normal cutting conditions, but especially cutting High-speed, and under heavy cutting conditions such as high cutting and high feed with high mechanical impact, because the high-temperature hardness and heat resistance of the hard coating layer is insufficient, and the strength is also insufficient In addition, since the progress of wear of the hard coating layer is further promoted and chipping is liable to occur, the service life is currently reached in a relatively short time.
[0007]
[Means for Solving the Problems]
In view of the above, the present inventors have constructed the above-mentioned conventional coated cermet tool in order to develop a coated cermet tool in which the hard coating layer exhibits excellent wear resistance especially under high-speed heavy cutting conditions. Focusing on the hard coating layer to do, as a result of conducting research,
(A) The (Ti, Al, B) N layer constituting the conventional coated cermet tool formed using the arc ion plating apparatus shown in FIG. 2 is substantially uniform over the entire layer thickness. Although it has a composition and therefore has a uniform high-temperature hardness, heat resistance, and strength, 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. That is, a rotary table for mounting a cermet substrate is provided in the center of the apparatus, and an Al-Ti-B alloy having a relatively high Al content is provided on one side and a Ti content having a relatively high Ti content is provided on the other side with the rotary table interposed therebetween. An arc ion plating apparatus in which a high Ti-Al-B alloy is opposed to each other as a cathode electrode (evaporation source) is used, and is located at a predetermined radial distance from a central axis on the rotary table of the apparatus. A plurality of cermet bases are mounted in a ring shape along the outer periphery of the table, and in this state, the rotary table is rotated while the atmosphere in the apparatus is a nitrogen atmosphere, and the thickness of the hard coating layer formed by vapor deposition is made uniform. While rotating the cermet substrate itself, an arc discharge is generated between the cathode electrode (evaporation source) and the anode electrode on both sides of the cermet substrate, and a composite nitride of Al, Ti and B is formed on the surface of the cermet substrate. , (Al—Ti, B) N] layer, the resulting (Al—Ti, B) N layer has the cermet substrate disposed on the turntable in a ring shape on the one side. At the point closest to the cathode electrode (evaporation source) of an Al-Ti-B alloy having a relatively high Al content, an Al highest content point is formed in the layer, and the cermet substrate is At the point closest to the cathode electrode of the Ti-Al-B alloy having a relatively high Ti content on the other side, a Ti maximum content point is formed in the layer. The Al maximum content point and the Ti maximum content point alternately and repeatedly appear at predetermined intervals along the direction, and Al and the Ti maximum content point from the Al maximum content point to the Al maximum content point from the Ti maximum content point. To have a component concentration distribution structure in which the Ti content changes continuously.
[0008]
(B) In the formation of the (Al-Ti, B) N layer having the repeated and continuously changing component concentration distribution structure of (a), the Al-Ti-B alloy as the cathode electrode (evaporation source) on one side of the opposed arrangement is used. The Al content is relatively higher than the Al content of the above-mentioned conventional Ti-Al-B alloy, and the Al content in the Ti-Al-B alloy which is the cathode electrode (evaporation source) on the other side. The amount is made relatively lower than the Al content of the above-mentioned conventional Ti-Al-B alloy, and the rotation speed of the turntable on which the cermet substrate is mounted is controlled,
The Al highest content point, the composition _{_{formula: (Al 1- (X + Z}} ) Ti X B Z) N ( provided that an atomic ratio, X is 0.05 to 0.25, Z is a 0.01 to 0.10 Show),
The Ti maximum content point, composition _{_{formula: (Ti 1- (Y + Z}} ) Al Y B Z) N ( provided that an atomic ratio, Y is 0.05 to 0.25, Z is a 0.01 to 0.10 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, B) N layer, the Al content exhibits higher high-temperature hardness and heat resistance. Since the Ti content is relatively higher in the Ti highest content portion than in the conventional (Ti, Al, B) N layer, the Ti content is much higher, and the Al highest content point and the Ti highest content are higher. Since the interval between the content points is extremely small, the layer as a whole has excellent high-temperature hardness and heat resistance while maintaining high strength. Therefore, the hard coating layer has such a structure (Al-Ti). , B) The coated cermet tool consisting of N layer is capable of chipping the hard coating layer even when cutting various kinds of steel and cast iron under high speed heavy cutting conditions, especially with high heat generation and high mechanical impact. Does not occur , To become to exert excellent wear resistance.
The research results shown in (a) and (b) above were obtained.
[0009]
The present invention has been made based on the above-mentioned research results, and a physical vapor deposition of a hard coating layer composed of an (Al—Ti, B) N layer on the surface of a cermet substrate with a total average layer thickness of 1 to 15 μm. Coated cermet 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, Having a component concentration distribution structure in which the Al and Ti contents continuously change from the highest content point to the Al highest content point,
Furthermore, the Al highest content point, the composition _{_{formula: (Al 1- (X + Z}} ) Ti X B Z) N ( provided that an atomic ratio, X is 0.05 to 0.25, Z is from 0.01 to 0. 10),
The Ti maximum content point, composition _{_{formula: (Ti 1- (Y + Z}} ) Al Y B Z) N ( provided that an atomic ratio, Y is 0.05 to 0.25, Z is a 0.01 to 0.10 Show),
And the interval between the adjacent Al maximum content points and adjacent Ti maximum content points is 0.01 to 0.1 μm,
The present invention is characterized by a coated cermet tool in which a hard coating layer exhibits excellent wear resistance under high-speed heavy cutting conditions.
[0010]
Next, the reason why the configuration of the hard coating layer constituting the coated cermet tool of the present invention is limited as described above will be described.
(A) The Al component at the Al maximum content point of the (Al-Ti, B) N layer, which is the composition hard coating layer having the highest Al content point, improves the high-temperature hardness and heat resistance, and the Ti component improves the strength. In addition, the B component has a function of further improving the high-temperature hardness, and therefore, the higher the content ratio of the Al component and the B component, the higher the high-temperature hardness and heat resistance, and suitable for high-speed cutting with high heat generation. 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 B, the ratio of Al becomes relatively large, and Ti having high strength is obtained. Even if the highest content points are adjacent to each other, a decrease in the strength of the layer itself is unavoidable. As a result, chipping and the like tend to occur. On the other hand, when the X value indicating the ratio of the Ti component exceeds 0.25, the relative That the ratio of Al decreases It is inevitable that the high-temperature hardness and the heat resistance decrease, which causes the acceleration of wear. Further, it is desirable that the Z value indicating the ratio of the B component is less than 0.01 in the ratio (atomic ratio) to the total amount of Al and Ti. Cannot improve the high-temperature hardness, and if the Z value exceeds 0.10, a decrease in strength that causes chipping or the like will occur. 25, and the Z value was defined as 0.01 to 0.10.
[0011]
(B) Composition of the highest Ti content point As described above, the highest Al content point is excellent in high-temperature hardness and heat resistance, but is inferior in strength, but is intended to compensate for the insufficient strength of the highest Al content point. The Ti content ratio is high, and the highest Ti content points that have high strength due to this are alternately interposed in the thickness direction. Therefore, the Y value indicating the Al content is determined by the total amount of Ti and B. If the occupying ratio (atomic ratio) exceeds 0.25, the ratio of Al becomes relatively large, and the desired excellent strength cannot be secured, while the Y value is also less than 0.05. If so, the proportion of Ti becomes relatively large, and the high-temperature hardness and heat resistance at the highest Ti content point sharply decrease, which causes abrasion promotion. Therefore, the Y value is set to 0.05 to 0.25. And the ratio of B component Z value indicating the specified to 0.01 to 0.10 for the same reason as in Al highest content point of the.
[0012]
(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 desired height of the hard coating layer is high. The strength, high-temperature hardness and heat resistance cannot be ensured, and if the interval exceeds 0.1 μm, the disadvantages of the respective points, that is, if the Al content is the highest, the strength is insufficient, and the Ti content is the highest. If the high-temperature hardness and the lack of heat resistance appear locally in the layer, chipping is likely to occur on the cutting edge due to this, and the progress of wear will be promoted, so the interval is 0.01 to It was determined to be 0.1 μm.
[0013]
(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.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, the coated cermet tool of the present invention will be specifically described with reference to examples.
(Example 1)
As raw material powders, WC powder, TiC powder, VC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, and Co powder each having an average particle diameter of 1 to 3 μm were prepared. The mixture was wet-mixed for 72 hours in a ball mill, dried and pressed into a green compact at a pressure of 100 MPa, and the green compact was heated to 1400 ° C. for 1 hour in a vacuum of 6 Pa. After sintering under the condition of holding, and after sintering, the cutting edge portion is subjected to honing processing of R: 0.03 to form a WC-based cemented carbide cermet substrate A1 to A10 having a chip shape of ISO standard CNMG120408. Formed.
[0015]
Further, as raw material powder, TiCN (TiC / TiN = 50/50 by weight) powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC powder each having an average particle diameter of 0.5 to 2 μm , Co powder, and Ni powder were prepared, and these raw material powders were blended in the composition shown in Table 2, wet-mixed in a ball mill for 24 hours, dried, and then pressed into a green compact at a pressure of 100 MPa. The green compact was sintered in a nitrogen atmosphere of 2 kPa at a temperature of 1500 ° C. for 1 hour, and after sintering, the cutting edge portion was subjected to a honing process of R: 0.03 to obtain an ISO standard CNMG120408. The cermet bases B1 to B6 made of TiCN-based cermet having the chip shape described above were formed.
[0016]
Next, each of the cermet substrates A1 to A10 and B1 to B6 was ultrasonically cleaned in acetone, dried, and then dried from the center axis on the rotary table in the arc ion plating apparatus shown in FIG. At a predetermined distance in the direction, a ring is attached along the outer periphery of the table, and as one cathode electrode (evaporation source), a Ti-Al-B alloy for forming the highest Ti content point having various component compositions As the cathode electrode (evaporation source) on the other side, Al-Ti-B alloys for forming the highest Al content points having various component compositions are arranged to face each other with the rotary table interposed therebetween, and metal Ti for bombarding is also mounted. First, the inside of the apparatus is heated to 500 ° C. with a heater while the inside of the apparatus is evacuated and maintained at a vacuum of 0.5 Pa or less, and then rotated while rotating on the rotary table. A dc bias voltage of -1000 V is applied to the cermet substrate, and an electric current of 100 A flows between the metal Ti of the cathode electrode and the anode electrode to generate an arc discharge, thereby cleaning the surface of the cermet substrate with Ti bombarding. Nitrogen gas was introduced into the apparatus as a reaction gas to obtain a reaction atmosphere of 2 Pa, and a -100 V DC bias voltage was applied to the cermet substrate rotating while rotating on the rotary table, and the respective cathode electrodes (the A current of 100 A is passed between the Ti-Al-B alloy for forming the highest Ti content point and the Al-Ti-B alloy for forming the highest Al content point) and the anode electrode to generate an arc discharge. On the surface, along the layer thickness direction, the Al maximum content point and the Ti maximum content point of the target compositions shown in Tables 3 and 4 The Al and Ti contents are alternately and repeatedly present at the target intervals shown in Tables 3 and 4, and the Al and Ti contents are respectively continuous 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. By depositing a hard coating layer having a component concentration distribution structure which changes gradually and having a target overall layer thickness also shown in Tables 3 and 4, the surface coated cermet tool of the present invention can be used as a coated cermet tool of the present invention. Chips (hereinafter referred to as coated chips of the present invention) 1 to 16 were manufactured.
[0017]
Further, for the purpose of comparison, these cermet substrates A1 to A10 and B1 to B6 were ultrasonically cleaned in acetone, and in a dried state, each was charged into a normal arc ion plating apparatus shown in FIG. As a cathode electrode (evaporation source), Ti-Al-B alloys having various component compositions are mounted, and further, metal Ti for bombarding is mounted. First, the inside of the apparatus is evacuated and kept at a vacuum of 0.5 Pa or less. While heating the inside of the apparatus to 500 ° C. with a heater, a DC bias voltage of −1000 V was applied to the cermet base, and a current of 100 A was passed between the metal Ti of the cathode electrode and the anode electrode to cause arcing. A discharge is generated, and the surface of the cermet substrate is cleaned by Ti bombarding. Then, a nitrogen gas is introduced into the apparatus as a reaction gas, and a reaction atmosphere of 2 Pa is applied. At the same time, a DC bias voltage of -100 V is applied to the cermet substrate, and a current of 100 A flows between the Ti-Al-B alloy of the cathode electrode and the anode electrode to generate an arc discharge. Have the target compositions and target layer thicknesses shown in Tables 5 and 6, and have substantially no composition change along the layer thickness direction (Ti, Al, B) By depositing a hard coating layer composed of N layers, conventional surface-coated cermet throw-away tips (hereinafter referred to as conventional coated tips) 1 to 16 as conventional coated cermet tools were produced, respectively.
[0018]
Next, in the state where each of the above-mentioned various coating tips is screwed to the tip of a tool steel tool with a fixing jig, the coating tips 1 to 10 of the present invention and the conventional coating tips 1 to 10 are:
Work material: JIS FC250 round bar,
Cutting speed: 450 m / min. ,
Cut: 4mm,
Feed: 0.3 mm / rev. ,
Cutting time: 15 minutes,
Dry continuous high-speed high-cut cutting test of cast iron under the following conditions:
Work material: JIS SNCM439 Lengthwise equally spaced round bar with four longitudinal grooves,
Cutting speed: 300 m / min. ,
Cut: 4.5 mm,
Feed: 0.2 mm / rev. ,
Cutting time: 5 minutes,
Intermittent high-speed high-cut cutting test of alloy steel under the following conditions:
Work material: JIS S50C round bar,
Cutting speed: 400 m / min. ,
Cut: 1.5 mm,
Feed: 0.6 mm / rev. ,
Cutting time: 10 minutes,
A dry continuous high-speed high-feed cutting test of carbon steel was performed under the following conditions.
[0019]
Further, for the coated chips 11 to 16 of the present invention and the coated chips 11 to 16 of the related art,
Work material: JIS FC300 round bar,
Cutting speed: 500 m / min. ,
Cut: 4.5 mm,
Feed: 0.4 mm / rev. ,
Cutting time: 15 minutes,
Dry continuous high-speed high-cut cutting test of cast iron under the following conditions:
Work material: JIS SCM435 Lengthwise round bar with four equally spaced longitudinal grooves,
Cutting speed: 300 m / min. ,
Cut: 4mm,
Feed: 0.4 mm / rev. ,
Cutting time: 5 minutes,
Intermittent high-speed high-cut cutting test of alloy steel under the following conditions:
Work material: JIS S55C round bar,
Cutting speed: 350 m / min. ,
Cut: 2mm,
Feed: 0.7 mm / rev. ,
Cutting time: 10 minutes,
A dry continuous high-speed high-feed cutting test of carbon steel was performed 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.
[0020]
[Table 1]

[0021]
[Table 2]

[0022]
[Table 3]

[0023]
[Table 4]

[0024]
[Table 5]

[0025]
[Table 6]

[0026]
[Table 7]

[0027]
(Example 2)
As raw material powders, medium coarse WC powder having an average particle diameter of 5.5 μm, fine WC powder of 0.8 μm, TaC powder of 1.3 μm, NbC powder of 1.2 μm, and ZrC of 1.2 μm Powder, 2.3 μm Cr ₃ C ₂ powder, 1.5 μm VC powder, 1.0 μm (Ti, W) C powder, and 1.8 μm Co powder were prepared. Each was blended into the blending composition shown in Table 8, further added wax, mixed in a ball mill for 24 hours in acetone, 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 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. In combination, diameters of 8 mm, 13 mm, and 2 mm mm cermet substrate forming round bar sintered bodies were formed, and the above 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 blade portion × Cermet 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 helix angle of 30 °, respectively. Manufactured.
[0028]
Next, these cermet substrates (end mills) C-1 to C-8 were ultrasonically cleaned in acetone, dried, and charged into an arc ion plating apparatus also shown in FIG. Under the same conditions as in Example 1, the Al maximum content point and the Ti maximum content point of the target composition shown in Table 9 alternately and repeatedly exist at the target intervals shown in Table 9 along the layer thickness direction. It has a component concentration distribution structure in which the Al and Ti contents continuously change from the highest content point to the highest Ti content point, and from the highest Ti content point to the highest Al content point. By depositing a hard coating layer having a total thickness, the surface-coated cermet end mills (hereinafter referred to as the coated end mills) 1 to 8 of the present invention as the coated cermet tools are respectively provided. And elephants.
[0029]
For the purpose of comparison, the above-mentioned cermet substrates (end mills) C-1 to C-8 were ultrasonically cleaned in acetone, dried, and then placed in a usual arc ion plating apparatus also shown in FIG. Under the same conditions as in Example 1 above, they had the target composition and target layer thickness shown in Table 10, and had substantially no composition change along the layer thickness direction (Ti, Al, B) By depositing a hard coating layer composed of N layers, end mills made of conventional surface-coated cermets (hereinafter referred to as conventional coated end mills) 1 to 8 as conventional coated cermet tools were respectively manufactured.
[0030]
Next, among the above coated end mills 1 to 8 of the present invention and conventional coated end mills 1 to 8, the coated end mills 1 to 3 and the coated end mills 1 to 3 of the present invention are:
Work material: Plane dimensions: 100 mm x 250 mm, thickness: 50 mm JIS S45C plate,
Cutting speed: 200 m / min. ,
Groove depth (cut): 1.5 mm,
Table feed: 1000 mm / min,
The dry-type high-speed high-feed groove cutting test of carbon steel under the conditions of the above, the coated end mills 4 to 6 of the present invention and the conventional coated end mills 4 to 6
Work material: Plane dimensions: 100 mm x 250 mm, thickness: 50 mm, JIS SS400 plate,
Cutting speed: 250 m / min. ,
Groove depth (cut): 5.5 mm,
Table feed: 1200 mm / min,
The dry-type high-speed high-cut groove cutting test of the structural steel under the conditions of the above, the coated end mills 7 and 8 of the present invention and the conventional coated end mills 7 and 8 are as follows.
Work material: Plane dimensions: 100 mm x 250 mm, thickness: 50 mm, JIS SKD61 plate,
Cutting speed: 180 m / min. ,
Groove depth (cut): 5 mm,
Table feed: 300 mm / min,
In each case, the flank wear width of the outer peripheral edge of the cutting edge reaches 0.1 mm, which is the standard of service life, in each of the dry high-speed high feed groove cutting tests of tool steel under the conditions of The cutting groove length up to was measured. The measurement results are shown in Tables 9 and 10, respectively.
[0031]
[Table 8]

[0032]
[Table 9]

[0033]
[Table 10]

[0034]
(Example 3)
The diameters produced in Example 2 above were 8 mm (for forming cermet substrates C-1 to C-3), 13 mm (for forming cermet substrates C-4 to C-6), and 26 mm (for cermet substrates C-7, C). -8) (for forming the cermet base D), the three types of round rod sintered bodies were subjected to grinding to form a groove formed portion having a diameter x length of 4 mm x 13 mm (cermet base D). -1 to D-3), dimensions of 8 mm × 22 mm (cermet substrate D-4 to D-6), and 16 mm × 45 mm (cermet substrate D-7, D-8), and 2 having a twist angle of 30 degrees. Cermet substrates (drills) D-1 to D-8 each having a single-blade shape were manufactured.
[0035]
Next, the cutting edges of these cermet bases (drills) D-1 to D-8 are honed, ultrasonically cleaned in acetone, and dried, and then applied to an arc ion plating apparatus also shown in FIG. Under the same conditions as in Example 1, the Al maximum content points and the Ti maximum content points of the target compositions shown in Table 11 were alternately arranged along the layer thickness direction at the target intervals shown in Table 11 as well. Having a component concentration distribution structure in which the Al and Ti contents are present repeatedly, and the Al and Ti contents continuously change from the Al highest content point to the Ti highest content point, from the Ti highest content point to the Al highest content point, and A drill made of the surface-coated cermet of the present invention as a coated cermet tool of the present invention (hereinafter, referred to as the coated drill of the present invention) as a coated cermet tool of the present invention by vapor-depositing a hard coating layer having a target overall layer thickness also shown in Table 11. 1 to 8 were prepared, respectively.
[0036]
For the purpose of comparison, the cutting edges of the cermet bases (drills) D-1 to D-8 are honed, ultrasonically cleaned in acetone, and dried, and are also shown in FIG. Under the same conditions as in Example 1 above, having the target composition and target layer thickness shown in Table 12, and having substantially no composition change along the layer thickness direction. By depositing a hard coating layer composed of a (Ti, Al, B) N layer, conventional surface-coated cermet drills (hereinafter, referred to as conventional coated carbide drills) 1 to 8 as conventional coated cermet tools were produced, respectively. .
[0037]
Next, among the above coated drills 1 to 8 of the present invention and conventional coated drills 1 to 8, the coated drills 1 to 3 of the present invention and the conventional coated drills 1 to 3 are:
Work material: Plane dimensions: 100 mm x 250 mm, thickness: 50 mm JIS SCM440 plate,
Cutting speed: 200 m / min. ,
Feed: 0.2 mm / rev,
Hole depth: 8mm,
For the wet-type high-speed and high-feed drilling cutting test of alloy steel under the following conditions, the coated drills 4 to 6 of the present invention and the conventional coated drills 4 to 6,
Work material: Plane dimensions: 100 mm x 250 mm, thickness: 50 mm, JIS SKD61 plate,
Cutting speed: 160 m / min. ,
Feed: 0.3 mm / rev,
Hole depth: 16mm,
For the wet high-speed and high-feed drilling cutting test of tool steel under the following conditions, the coated drills 7 and 8 of the present invention and the conventional coated drills 7 and 8,
Work material: Plane dimensions: 100 mm x 250 mm, thickness: 50 mm, JIS S55C plate,
Cutting speed: 175 m / min. ,
Feed: 0.4 mm / rev,
Hole depth: 32mm,
, High-speed high-feed drilling cutting test of carbon steel under the conditions described above, and in all wet drilling cutting tests (using water-soluble cutting oil), the flank wear width of the tip cutting edge reaches 0.3 mm. The number of drilling operations up to was measured. The measurement results are shown in Tables 11 and 12, respectively.
[0038]
[Table 11]

[0039]
[Table 12]

[0040]
As a result, the highest Al content point and highest Ti content in the hard coating layers of the coated tips 1 to 16, the coated end mills 1 to 8 and the coated drills 1 to 8 of the coated cermet tool of the present invention obtained as described above. Regarding the composition of the content points and the hard coating layers of the conventional coating tips 1 to 16, the conventional coating end mills 1 to 8 and the conventional coating drills 1 to 8 as the conventional coating cermet tools, Al, Ti, and When the content of B was measured using an Auger spectrometer, in the hard coating layer of the coated cermet tool of the present invention, the Al maximum content point and the Ti maximum content point had substantially the same composition and interval as the target values, respectively. Al and Ti are present alternately and repeatedly 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. Content is confirmed to have each continuously varying component concentration distribution structure, also showing the overall mean layer thickness even entire target layer thickness substantially the same value of the hard layer.
On the other hand, in the hard coating layer of the conventional coated cermet tool, no composition change is observed along the thickness direction, and the hard coating layer exhibits substantially the same composition as the target composition and substantially the same overall average layer thickness as the target overall layer thickness. Was confirmed.
[0041]
【The invention's effect】
From the results shown in Tables 3 to 12, the hard coating layer has a predetermined interval between the highest Al content point having excellent high-temperature hardness and heat resistance and the highest Ti content point having high strength in the layer thickness direction. The present invention has a component concentration distribution structure in which 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. All coated cermet tools are used for cutting various types of steel and cast iron 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 exhibits excellent wear resistance without occurrence of chipping, whereas the hard coating layer is composed of a (Ti, Al, B) N layer having substantially no composition change along the layer thickness direction. Conventional coating In the Met tool, under the high-speed heavy cutting conditions, the hard coating layer has insufficient high-temperature hardness and heat resistance, and insufficient strength. It is evident that time will lead to a service life.
As described above, the coated cermet 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., under high-speed heavy cutting conditions with high heat generation and high mechanical impact. In this case, since chipping does not occur and excellent wear resistance is exhibited, it is possible to satisfactorily 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 cermet tool of the present invention, (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 cermet tool.

Claims

A hard coating layer composed of a composite nitride layer of Al, Ti and B is physically deposited on the surface of a cermet substrate composed of a tungsten carbide-based cemented carbide or a titanium carbonitride cermet with a total average layer thickness of 1 to 15 μm. Surface-coated cermet cutting tools
In the hard coating layer, an Al maximum content point and a Ti maximum content point alternately and repeatedly exist at predetermined intervals along the layer thickness direction, and the Al maximum content point and the Ti maximum content point, Having a component concentration distribution structure in which the Al and Ti contents continuously change from the highest content point to the Al highest content point,
Furthermore, the Al highest content point, the composition _{_{formula: (Al 1- (X + Z}} ) Ti X B Z) N ( provided that an atomic ratio, X is 0.05 to 0.25, Z is from 0.01 to 0. 10),
The Ti maximum content point, composition _{_{formula: (Ti 1- (Y + Z}} ) Al Y B Z) N ( provided that an atomic ratio, Y is 0.05 to 0.25, Z is a 0.01 to 0.10 Shown),
And the interval between adjacent Al maximum content points and Ti maximum content points is 0.01 to 0.1 μm,
A surface-coated cermet cutting tool with a hard coating layer that exhibits excellent wear resistance under high-speed heavy cutting conditions.