JP3982347B2

JP3982347B2 - Surface-coated cemented carbide cutting tool with excellent wear resistance under high-speed heavy cutting conditions.

Info

Publication number: JP3982347B2
Application number: JP2002191555A
Authority: JP
Inventors: 秀充高岡; 惠滋中村
Original assignee: Mitsubishi Materials Corp
Current assignee: Mitsubishi Materials Corp
Priority date: 2002-07-01
Filing date: 2002-07-01
Publication date: 2007-09-26
Anticipated expiration: 2022-07-01
Also published as: JP2004034179A

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、さらに切刃が断続切削加工形態をとる面削加工や溝加工、肩加工などに用いられるソリッドタイプのエンドミルなどがあり、また前記スローアウエイチップを着脱自在に取り付けて前記ソリッドタイプのエンドミルと同様に切削加工を行うスローアウエイエンドミル工具などが知られている。
【０００３】
また、被覆超硬工具として、炭化タングステン（以下、ＷＣで示す）基超硬合金または炭窒化チタン（以下、ＴｉＣＮで示す）基サーメットからなる基体（以下、これらを総称して超硬基体と云う）の表面に、組成式：［Ｔｉ_1-( _Ｍ ₊ _Ｚ ₎Ａｌ_ＭＲ_Ｚ］Ｎ［ただし、前記組成式中、Ｒはイットリウムを含まない希土類金属を示し（以下同じ）、かついずれも原子比で、Ｍは０．４０〜０．６５、Ｚは０．００５〜０．１を示す］を満足するＴｉとＡｌとＲの複合窒化物［以下、（Ｔｉ，Ａｌ，Ｒ）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，Ｒ）Ｎ層がＡｌによる高温硬さと耐熱性、同Ｔｉによる強度と靭性を有し、さらにＲ成分による一段の高温硬さの向上効果と相俟って、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示す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、ヒーターで装置内を、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−Ｒ合金がセットされたカソード電極（蒸発源）との間に、例えば電流：９０Ａの条件でアーク放電を発生させ、同時に装置内に反応ガスとして窒素ガスを導入して、例えば２Ｐａの反応雰囲気とし、一方上記超硬基体には、例えば−２００Ｖのバイアス電圧を印加した条件で、前記超硬基体の表面に、上記（Ｔｉ，Ａｌ，Ｒ）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強め、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を余儀なくされる傾向にあるが、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、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、特に硬質被覆層の高温硬さおよび耐熱性が不足し、さらに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，Ｒ）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、さらに強度と靭性を有するが、例えば図１（ａ）に概略平面図で、同（ｂ）に概略正面図で示される構造のアークイオンプレーティング装置、すなわち装置中央部に超硬基体装着用回転テーブルを設け、前記回転テーブルを挟んで、一方側に相対的にＡｌ含有量の高いＡｌ−Ｔｉ−Ｒ合金、他方側に相対的にＴｉ含有量の高いＴｉ−Ａｌ−Ｒ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Ｒの複合窒化物［以下、（Ａｌ−Ｔｉ，Ｒ）Ｎで示す］層を形成すると、この結果の（Ａｌ−Ｔｉ，Ｒ）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−Ｒ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−Ｒ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。
【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，Ｒ）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−Ｒ合金におけるＴｉ含有量を上記の従来Ｔｉ−Ａｌ−Ｒ合金のＴｉ含有量に比して相対的に低くし、かつ同他方側のカソード電極（蒸発源）であるＴｉ−Ａｌ−Ｒ合金におけるＡｌ含有量は上記の従来Ｔｉ−Ａｌ−Ｒ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 ₊ _Ｚ ₎Ｔｉ_ＸＲ_Ｚ］Ｎ（ただし、原子比で、Ｘは０．０５〜０．３０、Ｚは０．００５〜０．１を示す）、
上記Ｔｉ最高含有点が、組成式：［Ｔｉ_1-( _Ｍ ₊ _Ｚ ₎Ａｌ_ＭＲ_Ｚ］Ｎ（ただし、原子比で、Ｍは０．０５〜０．３０、Ｚは０．００５〜０．１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，Ｒ）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，Ｒ）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相対的に一段と高い強度と靭性を保持した状態で一段とすぐれた高温難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，Ｒ）Ｎ層からなる被覆超硬工具は、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。
【０００８】
この発明は、上記の研究結果に基づいてなされたものであって、装置中央部に超硬基体装着用回転テーブルを設け、前記回転テーブルを挟んで、一方側にＡｌ最高含有点形成用Ａｌ−Ｔｉ−Ｒ合金、他方側にＴｉ最高含有点形成用Ｔｉ−Ａｌ−Ｒ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複数の前記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、前記超硬基体自体も自転させながら、前記の両側のカソード電極（蒸発源）とアノード電極との間にアーク放電を発生させて、前記超硬基体の表面に、（Ａｌ−Ｔｉ，Ｒ）Ｎ層からなる硬質被覆層を１〜１５μｍの全体平均層厚で蒸着してなる被覆超硬工具にして、
上記硬質被覆層が、層厚方向にそって、Ａｌ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_ＸＲ_Ｚ］Ｎ（ただし、原子比で、Ｘは０．０５〜０．３０、Ｚは０．００５〜０．１を示す）、
上記Ｔｉ最高含有点が、組成式：［Ｔｉ_1-( _Ｍ ₊ _Ｚ ₎Ａｌ_ＭＲ_Ｚ］Ｎ（ただし、原子比で、Ｍは０．０５〜０．３０、Ｚは０．００５〜０．１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，Ｒ）Ｎ層のＡｌ最高含有点の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Ｒ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Ｒ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、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Ｒ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Ｒ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０．００５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０．１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、Ｚ値を０．００５〜０．１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最高含有点は高温硬さおよび耐熱性のすぐれたものであるが、反面強度および靭性の劣るものであるため、このＡｌ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Ｍ値がＴｉとＲの合量に占める割合（原子比）で０．３０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Ｍ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最高含有点に所望の高温硬さおよび耐熱性を具備せしめることができなくなることから、Ｍ値を０．０５〜０．３０と定めたものであり、またＲ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０．００５〜０．１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、この結果層に所望の高強度および高靭性、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、Ｃｒ₃Ｃ₂粉末、およびＣｏ粉末を用意し、これら原料粉末を、表１に示される配合組成に配合し、ボールミルで７２時間湿式混合し、乾燥した後、１００ＭＰａの圧力で圧粉体にプレス成形し、この圧粉体を６Ｐａの真空中、温度：１４００℃に１時間保持の条件で焼結し、焼結後、切刃部分にＲ：０．０３のホーニング加工を施してＩＳＯ規格・ＣＮＭＧ１２０４０８のチップ形状をもったＷＣ基超硬合金製のチップ超硬基体Ａ−１〜Ａ−７，Ａ−９，およびＡ−１０をそれぞれ形成した。
【００１４】
また、原料粉末として、いずれも０．５〜２μｍの平均粒径を有するＴｉＣＮ（重量比で、ＴｉＣ／ＴｉＮ＝５０／５０）粉末、Ｍｏ₂Ｃ粉末、ＺｒＣ粉末、ＮｂＣ粉末、ＴａＣ粉末、ＷＣ粉末、Ｃｏ粉末、およびＮｉ粉末を用意し、これら原料粉末を、表２に示される配合組成に配合し、ボールミルで２４時間湿式混合し、乾燥した後、１００ＭＰａの圧力で圧粉体にプレス成形し、この圧粉体を２ｋＰａの窒素雰囲気中、温度：１５００℃に１時間保持の条件で焼結し、焼結後、切刃部分にＲ：０．０３のホーニング加工を施してＩＳＯ規格・ＣＮＭＧ１２０４０８のチップ形状をもったＴｉＣＮ系サーメット製のチップ超硬基体Ｂ−１〜Ｂ−６をそれぞれ形成した。
【００１５】
まず、カソード電極（蒸発源）であるＴｉ最高含有点形成用Ｔｉ−Ａｌ−Ｒ合金およびＡｌ最高含有点形成用Ａｌ−Ｔｉ−Ｒ合金の溶製に、原料として、以下、いずれも質量％で、純度：９９．６％の純Ｔｉ、および同９９．８％の純Ａｌ、さらにイットリウムを含まない希土類金属（Ｒ）として、
（ａ）純度：９９．９％のＬａ［以下、Ｒ（ａ）で示す］、
（ｂ）Ｃｅ：９６．９％を含有し、残りがＬａ、Ｎｄ、およびＰｒなどの希土類金属からなるＣｅ合金［以下、Ｒ（ｂ）で示す］、
（ｃ）Ｎｄ：７８％、Ｐｒ：１５％、Ｓｍ：２％、Ｌａ：４％を含有し、残りがその他の希土類金属からなるＮｄ合金［以下、Ｒ（ｃ）で示す］、
（ｄ）Ｃｅ：５２％、Ｎｄ：１８％、Ｌａ：２４％、Ｐｒ：５％を含有し、残りがその他の希土類金属からなるミッシュメタル合金［以下、Ｒ（ｄ）で示す］、
を用いて、種々の成分組成をもったＴｉ−Ａｌ−Ｒ（ａ）合金、Ｔｉ−Ａｌ−Ｒ（ｂ）合金、Ｔｉ−Ａｌ−Ｒ（ｃ）合金、およびＴｉ−Ａｌ−Ｒ（ｄ）合金、さらにＡｌ−Ｔｉ−Ｒ（ａ）合金、Ａｌ−Ｔｉ−Ｒ（ｂ）合金、Ａｌ−Ｔｉ−Ｒ（ｃ）合金、およびＡｌ−Ｔｉ−Ｒ（ｄ）合金を製造した。
ついで、上記のチップ超硬基体Ａ−１〜Ａ−７，Ａ−９，およびＡ−１０、並びにＢ−１〜Ｂ−６のそれぞれを、アセトン中で超音波洗浄し、乾燥した状態で、図１に示されるアークイオンプレーティング装置内の回転テーブル上の中心軸から半径方向に所定距離離れた位置にリング状に装着し、一方側のカソード電極（蒸発源）として、上記の種々の成分組成をもったＴｉ最高含有点形成用Ｔｉ−Ａｌ−Ｒ（ａ）〜（ｄ）合金、他方側のカソード電極（蒸発源）として、同じく上記の種々の成分組成をもったＡｌ最高含有点形成用Ａｌ−Ｔｉ−Ｒ（ａ）〜（ｄ）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チップ超硬基体に−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、もってチップ超硬基体表面を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チップ超硬基体に−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−Ｒ（ａ）〜（ｄ）合金およびＡｌ最高含有点形成用Ａｌ−Ｔｉ−Ｒ（ａ）〜（ｄ）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、もって前記チップ超硬基体の表面に、層厚方向に沿って表３に示される目標組成のＡｌ最高含有点とＴｉ最高含有点とが交互に同じく表３に示される目標間隔で繰り返し存在し、かつ前記Ａｌ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）１〜１５をそれぞれ製造した。
【００１６】
また、比較の目的で、これらチップ超硬基体Ａ−１〜Ａ−７，Ａ−９，およびＡ−１０、並びにＢ−１〜Ｂ−６を、アセトン中で超音波洗浄し、乾燥した状態で、それぞれ図２に示される通常のアークイオンプレーティング装置に装入し、カソード電極（蒸発源）として種々の成分組成をもったＴｉ−Ａｌ−Ｒ（ａ）〜（ｄ）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４５０℃に加熱した後、前記チップ超硬基体に−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、もってチップ超硬基体表面を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、チップ超硬基体に−２００Ｖの直流バイアス電圧を印加し、前記カソード電極のＴｉ−Ａｌ−Ｒ（ａ）〜（ｄ）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、もって前記チップ超硬基体のそれぞれの表面に、表４に示される目標組成および目標層厚を有し、かつ層厚方向に沿って実質的に組成変化のない（Ｔｉ，Ａｌ，Ｒ）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）１〜１５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１〜１５および従来被覆超硬チップ１〜１５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：３４０ｍ／ｍｉｎ、
切り込み：６ｍｍ、
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：３４０ｍ／ｍｉｎ、
切り込み：１．２ｍｍ、
送り：０．５３ｍｍ／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：３５５ｍ／ｍｉｎ、
切り込み：６ｍｍ、
送り：０．１７ｍｍ／ｒｅｖ、
切削時間：５分、
の条件での鋳鉄の乾式連続高速高切り込み切削加工試験を行い、いずれの切削加工試験でも切刃の逃げ面摩耗幅を測定した。この測定結果を表５に示した。
【００１８】
【表１】

【００１９】
【表２】

【００２０】
【表３】

【００２１】
【表４】

【００２２】
【表５】

【００２３】
（実施例２）
原料粉末として、平均粒径：４．５μｍ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１．６μｍのＣｒ₃Ｃ₂粉末、同１．５μｍのＶＣ粉末、同１．０μｍの（Ｔｉ，Ｗ）Ｃ粉末、および同１．８μｍのＣｏ粉末を用意し、これら原料粉末をそれぞれ表６に示される配合組成に配合し、さらにワックスを加えてアセトン中で６０時間ボールミル混合し、減圧乾燥した後、１００ＭＰａの圧力で所定形状の各種の圧粉体にプレス成形し、これらの圧粉体を、６Ｐａの真空雰囲気中、７℃／分の昇温速度で１３７０〜１４７０℃の範囲内の所定の温度に昇温し、この温度に１時間保持後、炉冷の条件で焼結して、直径が８ｍｍ、１３ｍｍ、および２６ｍｍの３種の超硬基体形成用丸棒焼結体Ｃ−１〜Ｃ−８を形成し、さらに前記の３種の丸棒焼結体のうちの丸棒焼結体Ｃ−１〜Ｃ−３，およびＣ−５〜Ｃ−８から、研削加工にて、表６に示される組合せで、切刃部の直径×長さがそれぞれ６ｍｍ×１３ｍｍ、１０ｍｍ×２２ｍｍ、および２０ｍｍ×４５ｍｍの寸法を有し、かついずれもねじれ角：３０度の４枚刃スクエア形状をもったエンドミル超硬基体をそれぞれ製造した。
【００２４】
ついで、これらのエンドミル超硬基体を、アセトン中で超音波洗浄し、乾燥した状態で、同じく図１に示されるアークイオンプレーティング装置に装入し、上記実施例１と同一の条件で、層厚方向に沿って表７に示される目標組成のＡｌ最高含有点とＴｉ最高含有点とが交互に同じく表７に示される目標間隔で繰り返し存在し、かつ前記Ａｌ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７に示される目標全体層厚の硬質被覆層を蒸着することにより、本発明被覆超硬工具としての本発明表面被覆超硬合金製エンドミル（以下、本発明被覆超硬エンドミルと云う）１〜７をそれぞれ製造した。
【００２５】
また、比較の目的で、上記のエンドミル超硬基体を、アセトン中で超音波洗浄し、乾燥した状態で、同じく図２に示される通常のアークイオンプレーティング装置に装入し、上記実施例１と同一の条件で、表８に示される目標組成および目標層厚を有し、かつ層厚方向に沿って実質的に組成変化のない（Ｔｉ，Ａｌ，Ｒ）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）１〜７をそれぞれ製造した。
【００２６】
つぎに、上記本発明被覆超硬エンドミル１〜７および従来被覆超硬エンドミル１〜７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：３５０ｍ／ｍｉｎ、
軸方向切り込み：５ｍｍ、
径方向切り込み：０．７ｍｍ、
テーブル送り：２２００ｍｍ／分、
の条件での鋳鉄の湿式高速高送り側面切削加工試験、本発明被覆超硬エンドミル４，５および従来被覆超硬エンドミル４，５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：３５０ｍ／ｍｉｎ、
軸方向切り込み：７ｍｍ、
径方向切り込み：１ｍｍ、
テーブル送り：２０５０ｍｍ／分、
の条件での軟鋼の湿式高速高送り側面切削加工試験、本発明被覆超硬エンドミル６，７および従来被覆超硬エンドミル６，７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：３３５ｍ／ｍｉｎ、
軸方向切り込み：１２ｍｍ、
径方向切り込み：１．５ｍｍ、
テーブル送り：１５５０ｍｍ／分、
の条件での炭素鋼の湿式高速高送り側面切削加工試験をそれぞれ行い、いずれの湿式側面切削加工試験（水溶性切削油使用）でも切刃部の外周刃の逃げ面摩耗幅が使用寿命の目安とされる０．１ｍｍに至るまでの切削長を測定した。この測定結果を表７、８にそれぞれ示した。
【００２７】
【表６】

【００２８】
【表７】

【００２９】
【表８】

【００３０】
（実施例３）
上記の実施例２で製造した直径が８ｍｍ、１３ｍｍ、および２６ｍｍの３種の丸棒焼結体のうちの丸棒焼結体Ｃ−１〜Ｃ−７を用い、この丸棒焼結体から、研削加工にて、表６に示される組合せで、溝形成部の直径×長さがそれぞれ４ｍｍ×１３ｍｍ、８ｍｍ×２２ｍｍ、および１６ｍｍ×４５ｍｍの寸法を有し、かついずれもねじれ角：３０度の２枚刃形状をもったドリル超硬基体をそれぞれ製造した。
【００３１】
ついで、これらのドリル超硬基体の切刃に、ホーニングを施し、アセトン中で超音波洗浄し、乾燥した状態で、同じく図１に示されるアークイオンプレーティング装置に装入し、上記実施例１と同一の条件で、層厚方向に沿って表９に示される目標組成のＡｌ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ドリル（以下、本発明被覆超硬ドリルと云う）１〜７をそれぞれ製造した。
【００３２】
また、比較の目的で、上記のドリル超硬基体の切刃に、ホーニングを施し、アセトン中で超音波洗浄し、乾燥した状態で、同じく図２に示される通常のアークイオンプレーティング装置に装入し、上記実施例１と同一の条件で、表１０に示される目標組成および目標層厚を有し、かつ層厚方向に沿って実質的に組成変化のない（Ｔｉ，Ａｌ，Ｒ）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）１〜７をそれぞれ製造した。
【００３３】
つぎに、上記本発明被覆超硬ドリル１〜７および従来被覆超硬ドリル１〜７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：２３５ｍ／ｍｉｎ、
送り：０．５２ｍｍ／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：２４５ｍ／ｍｉｎ、
送り：０．５８ｍｍ／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および従来被覆超硬ドリル７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：２５５ｍ／ｍｉｎ、
送り：０．６１ｍｍ／ｒｅｖ、
穴深さ：２８ｍｍ
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９，１０にそれぞれ示した。
【００３４】
【表９】

【００３５】
【表１０】

【００３６】
この結果得られた本発明被覆超硬工具としての本発明被覆超硬チップ１〜１５、本発明被覆超硬エンドミル１〜７、および本発明被覆超硬ドリル１〜７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１〜１５、従来被覆超硬エンドミル１〜７、および従来被覆超硬ドリル１〜７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。
【００３７】
【発明の効果】
表３〜１０に示される結果から、硬質被覆層が層厚方向に、すぐれた高温硬さと耐熱性を有するＡｌ最高含有点と、高強度と高靭性を有する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，Ｒ）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、並び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することから、比較的短時間で使用寿命に至ることが明らかである。
上述のように、この発明の被覆超硬工具は、通常の条件での切削加工は勿論のこと、特に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]
BACKGROUND OF THE INVENTION
This invention has excellent high temperature hardness and heat resistance, and high strength and toughness due to its hard coating layer. Therefore, cutting of various types of steel and cast iron, especially at high speed with high heat generation and high mechanical strength. A surface-coated cemented carbide cutting tool that exhibits excellent wear resistance without the occurrence of chipping (microchips) in the hard coating layer when performed under heavy cutting conditions such as high cutting with impact and high feed ( Hereinafter, it is related to a coated carbide tool.
[0002]
[Prior art]
In general, coated carbide tools are used for throwaway inserts that are detachably attached to the tip of a cutting tool for drilling and cutting of various materials such as steel and cast iron, and for flat cutting. There are drills, miniature drills, solid type end mills used for chamfering, grooving, shoulder processing, etc. in which the cutting blade takes an intermittent cutting form, and the solid type by attaching the throwaway tip detachably A slow-away end mill tool that performs a cutting process in the same manner as an end mill is known.
[0003]
Further, as a coated carbide tool, a substrate made of tungsten carbide (hereinafter referred to as WC) -based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) -based cermet (hereinafter collectively referred to as a cemented carbide substrate). on the surface of) the composition _{_{_{_{formula: [Ti 1- (M + Z}}}} ) Al M R Z] N [ However, in the composition formulas, R represents a rare earth metal containing no yttrium (hereinafter the same), and both atoms The composite nitride of Ti, Al, and R satisfying the following ratio: M is 0.40 to 0.65 and Z is 0.005 to 0.1 [hereinafter referred to as (Ti, Al, R) N] A coated carbide tool formed by physically vapor-depositing a hard coating layer made of a layer with an average layer thickness of 1 to 15 μm is proposed, and the coated carbide tool constitutes the hard coating layer (Ti, Al, R). N layer has high temperature hardness and heat resistance with Al, strength and toughness with Ti And, I further improvement coupled with the single-stage high-temperature hardness by R component, are also known to exhibit cutting performance with superior in continuous cutting or interrupted cutting of various steels and cast iron.
[0004]
Furthermore, the above-mentioned coated carbide tool is, for example, the above-mentioned carbide substrate is loaded into an arc ion plating apparatus which is one type of physical vapor deposition apparatus schematically shown in FIG. For example, an arc discharge is generated between the anode electrode and a cathode electrode (evaporation source) on which a Ti—Al—R alloy having a predetermined composition is set, for example, at a current of 90 A, while being heated to a temperature of 500 ° C. At the same time, nitrogen gas is introduced into the apparatus as a reaction gas to form a reaction atmosphere of, for example, 2 Pa. On the other hand, the carbide substrate is applied to the surface of the carbide substrate under a condition that a bias voltage of, for example, −200 V is applied. It is also known that it is produced by vapor-depositing a hard coating layer composed of the (Ti, Al, R) N layer.
[0005]
[Problems to be solved by the invention]
In recent years, there has been a remarkable increase in performance of cutting devices. On the other hand, there is a strong demand for labor saving and energy saving and further cost reduction for cutting. Although there is a tendency to be forced to perform cutting under heavy cutting conditions such as high feed, there is no problem when using the above conventional coated carbide tools under normal cutting conditions. Is performed at high speed and under heavy cutting conditions such as high cutting and high feed with high mechanical impact, especially the hard coating layer lacks high-temperature hardness and heat resistance, and also has insufficient strength and toughness. Therefore, the progress of wear of the hard coating layer is further promoted and chipping is likely to occur, so that the service life is reached in a relatively short time.
[0006]
[Means for Solving the Problems]
In view of the above, the present inventors have developed the above-mentioned conventional coated carbide tool in order to develop a coated carbide tool that exhibits excellent wear resistance with a hard coating layer particularly under high-speed heavy cutting conditions. As a result of conducting research focusing on the hard coating layer that composes
(A) The (Ti, Al, R) N layer constituting the conventional coated carbide tool formed using the arc ion plating apparatus shown in FIG. 2 is substantially uniform over the entire thickness. Arc ion having a structure as shown in FIG. 1 (a) in a schematic plan view and FIG. 1 (b) in a schematic front view. A plating apparatus, that is, a rotating table for mounting a cemented carbide substrate is provided at the center of the apparatus, and an Al-Ti-R alloy having a relatively high Al content is disposed on one side with the rotating table interposed therebetween, and relatively on the other side. Using an arc ion plating apparatus in which a Ti-Al-R alloy having a high Ti content is disposed as a cathode electrode (evaporation source) opposite to each other, the apparatus is positioned at a predetermined distance in the radial direction from the central axis on the rotary table. Multiple The carbide substrate is mounted in a ring shape, and in this state, the atmosphere inside the apparatus is changed to a nitrogen atmosphere, the rotary table is rotated, and the carbide substrate itself is rotated for the purpose of uniforming the thickness of the hard coating layer formed by vapor deposition. Then, an arc discharge is generated between the cathode electrode (evaporation source) and the anode electrode on both sides, and a composite nitride of Al, Ti, and R [hereinafter referred to as (Al-Ti] , R) N]] layer is formed, the resulting (Al—Ti, R) N layer has the carbide substrate disposed in a ring shape on the rotary table, relatively on the one side. At the point closest to the cathode electrode (evaporation source) of the Al-Ti-R alloy having a high Al content, the Al highest content point is formed in the layer, and the carbide substrate is relatively Ti on the other side. High content of Ti-Al-R alloy When the closest point to the cathode electrode is reached, the highest Ti content point is formed in the layer, and the rotation of the rotary table causes the highest Al content point and the highest Ti content point to have a predetermined distance along the layer thickness in the layer. In addition to appearing alternately, it has 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 from the Ti highest content point to the Al highest content point, respectively. To become a.
[0007]
(B) In the formation of the (Al—Ti, R) N layer having the repeated continuous change component concentration distribution structure of (a) above, in the Al—Ti—R alloy which is the cathode electrode (evaporation source) on one side of the opposing arrangement The Ti content in the Ti-Al-R alloy, which is a cathode electrode (evaporation source) on the other side, is relatively lower than the Ti content of the conventional Ti-Al-R alloy. Is relatively low compared to the Al content of the conventional Ti-Al-R alloy, and controls the rotational speed of the rotary table on which the carbide substrate is mounted,
The Al highest content point, composition _{_{_{_{formula: [Al 1- (X + Z}}}} ) Ti X R Z] N ( provided that an atomic ratio, X is 0.05 to 0.30, Z is from 0.005 to 0. 1),
The Ti maximum content point, composition _{_{_{_{formula: [Ti 1- (M + Z}}}} ) Al M R Z] N ( provided that an atomic ratio, M is 0.05 to 0.30, Z is from 0.005 to 0. 1),
And the distance in the thickness direction between the adjacent Al highest content point and Ti highest content point adjacent to each other is 0.01 to 0.1 μm,
In the Al highest content point portion, the Al content is relatively higher than the conventional (Ti, Al, R) N layer described above, and thus exhibits higher temperature hardness and heat resistance. In the Ti highest content point portion, the Ti content is relatively higher than that of the conventional (Ti, Al, R) N layer, so that it has higher strength and toughness, and these Al highest content points Since the interval between the highest Ti content points is extremely small, the entire layer has relatively high strength and toughness while maintaining relatively high strength and toughness. Coated carbide tools consisting of (Al-Ti, R) N layers with such a structure perform cutting of various steels and cast iron, especially under high-speed heavy cutting conditions with high heat generation and high mechanical impact. Hard Without occurrence of chipping in the 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 is provided with a rotating table for mounting a carbide substrate at the center of the apparatus, sandwiching the rotating table, and Al— Using an arc ion plating apparatus in which a Ti-R alloy and a Ti-Al-R alloy for forming the highest Ti content point on the other side are arranged to face each other as a cathode electrode (evaporation source), from the central axis on the rotary table of the apparatus A plurality of the carbide substrates are attached in a ring shape at a position separated by a predetermined distance in the radial direction, and while rotating the rotary table with the atmosphere inside the apparatus as a nitrogen atmosphere in this state, while rotating the carbide substrate itself, by generating arc discharge between the cathode (evaporation source) and an anode electrode on both sides of the the surface of the cemented carbide substrate, a hard coating layer made of (Al-Ti, R) N layer In the overall average layer formed by vapor deposition in a thickness coated cemented carbide of 15 m,
In the hard coating layer, the highest Al content point and the highest Ti content point are repeatedly present at predetermined intervals along the layer thickness direction, and the highest Ti content point, the highest Ti content point, and the highest Ti content point 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, respectively,
Furthermore, the Al highest content point is the composition formula: [Al _{1- (} _X ₊ _Z ₎ Ti _X R _Z ] N (wherein X is 0.05 to 0.30 and Z is 0.005 to 0.005 in atomic ratio). 0.1)
The Ti maximum content point, composition _{_{_{_{formula: [Ti 1- (M + Z}}}} ) Al M R Z] N ( provided that an atomic ratio, M is 0.05 to 0.30, Z is from 0.005 to 0. 1),
And the interval between the Al highest content point and the Ti highest content point adjacent to each other is 0.01 to 0.1 μm.
It is characterized by a coated carbide tool that exhibits excellent wear resistance with a hard coating layer under high-speed heavy cutting conditions.
[0009]
Next, in the coated carbide tool of the present invention, the reason why the structure of the hard coating layer constituting the tool is limited as described above will be described.
(A) Composition of Al highest content point Al component of Al highest content point of (Al-Ti, R) N layer improves high temperature hardness and heat resistance, and the Ti component improves strength and toughness. The R component has the effect of further improving the high temperature hardness. Therefore, the higher the content ratio of the Al component and the R component, the higher the high temperature hardness and heat resistance, and it is suitable for high speed cutting with high heat generation. However, when the X value indicating the proportion of Ti is less than 0.05 in the proportion of the total amount of Al and R (atomic ratio), the proportion of Al becomes relatively large, resulting in high strength and high toughness. Even if the highest Ti content point is present adjacently, a decrease in the strength and toughness of the layer itself is inevitable, and as a result, chipping and the like are likely to occur, while the X value indicating the Ti ratio is 0.30. If it exceeds, the proportion of Al is relatively It becomes too small that the desired excellent high-temperature hardness and heat resistance cannot be ensured, and the Z value indicating the ratio of R is 0 in terms of the total amount of Al and Ti (atomic ratio). If it is less than 0.005, the desired high-temperature hardness improvement effect cannot be obtained, and if the Z value exceeds 0.1, the strength and toughness will rapidly decrease. .30 and Z value were determined to be 0.005 to 0.1, respectively.
[0010]
(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 on the other hand, it is inferior in strength and toughness. In order to make up for the lack of toughness, the Ti content is high, thereby alternately interposing in the thickness direction the highest Ti content points that have high strength and high toughness. Therefore, the M value indicating the Al content If the ratio (atomic ratio) in the total amount of Ti and R exceeds 0.30 , the ratio of Al becomes relatively large, and the desired excellent strength and toughness cannot be ensured. If the M value is also less than 0.05, the ratio of Ti is relatively increased, and the Ti highest content point cannot be provided with the desired high-temperature hardness and heat resistance. 0.05 Are as hereinbefore defined and .30, also Z value indicating a ratio of the R component is defined as 0.005 to 0.1 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 distance is less than 0.01 μm, it is difficult to clearly form each point with the above composition. High toughness, excellent high-temperature hardness and heat resistance cannot be ensured, and when the distance exceeds 0.1 μm, each point has defects, that is, if Al is the highest content point, insufficient strength and toughness, Ti If it is the highest content point, high temperature hardness and insufficient heat resistance will appear locally in the layer, which makes it easier for chipping to occur on the cutting edge and promotes wear progress. Was determined to be 0.01 to 0.1 μm.
[0012]
(D) Overall average layer thickness of hard coating layer If the layer thickness is less than 1 μm, the desired wear resistance cannot be ensured. On the other hand, if the average layer thickness exceeds 15 μm, chipping tends to occur. Therefore, the average layer thickness was determined to be 1 to 15 μm.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Next, the coated carbide tool of the present invention will be specifically described with reference to examples.
Example 1
As raw material powders, WC powder, TiC powder, VC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, and Co powder, all having an average particle diameter of 1 to 3 μm, were prepared. And then wet-mixed with a ball mill for 72 hours, dried, and press-molded into a green compact at a pressure of 100 MPa. The green compact was vacuumed at 6 Pa at a temperature of 1400 ° C. for 1 hour. Sintered under holding conditions, and after sintering, the cutting edge portion was subjected to a honing process of R: 0.03, and a chip cemented carbide substrate A- made of a WC-based cemented carbide alloy having a chip shape of ISO standard / CNMG120408 1 to A-7, A-9, and A-10 were formed.
[0014]
In addition, as raw material powders, all are TiCN (weight ratio, TiC / TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC having an average particle diameter of 0.5 to 2 μm. Prepare powder, Co powder, and Ni powder, mix these raw material powders into the composition shown in Table 2, wet mix for 24 hours with a ball mill, dry, and press-mold into green compact at 100 MPa pressure The green compact was sintered in a nitrogen atmosphere of 2 kPa at a temperature of 1500 ° C. for 1 hour. After sintering, the cutting edge portion was subjected to a honing process of R: 0.03 to meet ISO standards / Chip carbide substrates B-1 to B-6 made of TiCN cermet having a chip shape of CNMG120408 were formed.
[0015]
First, as a raw material for melting Ti-Al-R alloy for forming the highest Ti content point and Al-Ti-R alloy for forming the highest Al content point as the cathode electrode (evaporation source) Purity: 99.6% pure Ti, 99.8% pure Al, and a rare earth metal (R) containing no yttrium ,
(A) Purity: 99.9% La [hereinafter referred to as R (a)],
(B) Ce: Ce alloy containing 96.9%, and the remainder consisting of rare earth metals such as La, Nd, and Pr [hereinafter referred to as R (b)],
(C) Nd alloy containing Nd: 78%, Pr: 15%, Sm: 2%, La: 4%, and the rest consisting of other rare earth metals [hereinafter referred to as R (c)],
(D) A Misch metal alloy containing Ce: 52%, Nd: 18%, La: 24%, Pr: 5%, and the remainder consisting of other rare earth metals [hereinafter referred to as R (d)],
Ti-Al-R (a) alloy, Ti-Al-R (b) alloy, Ti-Al-R (c) alloy, and Ti-Al-R (d) having various component compositions Alloys, as well as Al-Ti-R (a) alloys, Al-Ti-R (b) alloys, Al-Ti-R (c) alloys, and Al-Ti-R (d) alloys were produced.
Next, each of the above chip carbide substrates A-1 to A-7, A-9, and A-10, and B-1 to B-6 was ultrasonically cleaned in acetone and dried. 1 is mounted in a ring shape at a predetermined distance in the radial direction from the central axis on the rotary table in the arc ion plating apparatus shown in FIG. 1, and the above-mentioned various components are used as a cathode electrode (evaporation source) on one side. Ti-Al-R (a) to (d) alloys for forming the highest Ti content point having the composition, and forming the highest Al content point having the above-mentioned various component compositions as the cathode electrode (evaporation source) on the other side Al-Ti-R (a) to (d) alloys for use are placed opposite to each other with the rotary table in between, and a bombard cleaning metal Ti is also mounted. First, the inside of the apparatus is evacuated to a vacuum of 0.5 Pa or less. While holding, 50 inside the device with a heater After heating to ° C., the chip carbide substrate rotates while rotating on the turntable by applying a DC bias voltage of -1000 V, and passing a 100A current between said metallic Ti and the anode electrode of the cathode electrode to generate arc discharge Te, with a chip carbide substrate surface was washed Ti bombardment with, as well as the reaction atmosphere of 3Pa then introducing nitrogen gas as a reaction gas into the apparatus, rotates while rotating on the turntable A direct bias voltage of −30 V was applied to the chip carbide substrate, and each cathode electrode [Ti-Al-R (a) to (d) alloy for forming the highest Ti content point and Al— for forming the highest Al content point) Table of Ti-R (a) ~ ( d) alloy and by applying a 140A current to generate arc discharge between the anode electrode, with it the tip carbide substrate , The exist repeatedly in the target interval and Al up to contain point and Ti highest content point of the target composition shown in Table 3 along the thickness direction are shown also in Table 3 alternately, and the from the Al highest content point Ti highest content point, having a component concentration distribution structure in which the Al and Ti contents continuously change from the highest Ti content point to the highest Al content point, and having the target total layer thickness as shown in Table 3 By depositing the coating layer, throwaway tips made of the surface coated cemented carbide of the present invention (hereinafter referred to as the present coated carbide tips) 1 to 15 as the coated carbide tools of the present invention were produced.
[0016]
Further, for the purpose of comparison, these chip superhard substrates A-1 to A-7, A-9, and A-10, and B-1 to B-6 were ultrasonically washed in acetone and dried. 2 were each inserted into the ordinary arc ion plating apparatus shown in FIG. 2, and Ti—Al—R (a) to (d) alloys having various component compositions were mounted as cathode electrodes (evaporation sources). Further, a metallic Ti for bombard cleaning was also mounted, and first, the inside of the apparatus was evacuated and kept at a vacuum of 0.5 Pa or less, and the inside of the apparatus was heated to 450 ° C. with a heater, and then −1000 V was applied to the chip carbide substrate. And a current of 100 A is applied between the metal Ti of the cathode electrode and the anode electrode to generate an arc discharge, thereby cleaning the surface of the chip carbide substrate with Ti bombardment, reaction By introduction of nitrogen gas as a scan with a reaction atmosphere of 2 Pa, and applying a DC bias voltage of -200V to the chip carbide substrate, Ti-Al-R (a ) of the cathode electrodes ~ (d) alloy and an anode by flowing a 90A current between the electrodes to generate arc discharge, on each surface of the chip carbide substrate with has a target composition and target layer thicknesses shown in Table 4, and along the thickness direction By depositing a hard coating layer consisting of a (Ti, Al, R) N layer substantially unchanged in composition, a conventional surface-coated cemented carbide throwaway tip (hereinafter referred to as conventional coating) as a conventional coated carbide tool 1 to 15 were manufactured.
[0017]
Next, with the present invention coated carbide tips 1-15 and conventional coated carbide tips 1-15 , in a state where this is screwed to the tip of the tool steel tool with a fixing jig,
Work material: JIS / S20C round bar,
Cutting speed: 340 m / min,
Incision: 6mm,
Feed: 0.15mm / rev,
Cutting time: 5 minutes
Dry continuous high-speed high-cut cutting test of carbon steel under the conditions of
Work material: JIS / SS400 lengthwise equidistant 4 round bars with flutes,
Cutting speed: 340 m / min,
Cutting depth: 1.2mm,
Feed: 0.53mm / rev,
Cutting time: 5 minutes
Dry intermittent high-speed high-feed cutting test of mild steel under the conditions of
Work material: JIS / FC200 round bar,
Cutting speed: 355 m / min,
Incision: 6mm,
Feed: 0.17mm / rev,
Cutting time: 5 minutes
The dry continuous high-speed, high-cut cutting test of cast iron was performed under the conditions described above, and the flank wear width of the cutting edge was measured in any cutting test. The measurement results are shown in Table 5 .
[0018]
[Table 1]

[0019]
[Table 2]

[0020]
[Table 3]

[0021]
[Table 4]

[0022]
[Table 5]

[0023]
(Example 2)
As raw material powders, medium coarse WC powder having an average particle size of 4.5 μm, fine WC powder of 0.8 μm, TaC powder of 1.3 μm, NbC powder of 1.2 μm, ZrC of 1.2 μm Prepare a powder, 1.6 μm Cr ₃ C ₂ powder, 1.5 μm VC powder, 1.0 μm (Ti, W) C powder, and 1.8 μm Co powder. Each was blended in the blending composition shown in Table 6 , further added with wax, ball milled in acetone for 60 hours, dried under reduced pressure, and then pressed into various compacts of a predetermined shape at a pressure of 100 MPa. The green compact is heated to a predetermined temperature in the range of 1370 to 1470 ° C. at a rate of temperature increase of 7 ° C./min in a 6 Pa vacuum atmosphere, held at this temperature for 1 hour, and then fired under furnace cooling conditions. Finally, the diameters are 8mm, 13mm, and 26 Three carbide substrate for forming a round bar sintered C-1 through C-8 of the m forming, further round bar sintered C-1 through C of the three kinds of rod sintered body of the From -3 and C-5 to C-8 , the diameters and lengths of the cutting edge portions are 6 mm x 13 mm, 10 mm x 22 mm, and 20 mm x 45 mm in the combinations shown in Table 6 by grinding. The end mill carbide substrates each having a four-blade square shape with a twist angle of 30 degrees were manufactured.
[0024]
Next, these end mill carbide substrates were ultrasonically cleaned in acetone and dried, and then charged into the arc ion plating apparatus shown in FIG. The highest Al content point and the highest Ti content point of the target composition shown in Table 7 along the thickness direction are alternately repeated at the same target interval shown in Table 7 , and the highest Ti content from the Al highest content point. A hard coating layer having a component concentration distribution structure in which the Al and Ti contents continuously change from the highest Ti content point to the highest Al content point, and having the target total layer thickness shown in Table 7 By vapor deposition, end mills made of the surface coated cemented carbide of the present invention (hereinafter referred to as the present coated carbide end mill) 1 to 7 as the coated carbide tools of the present invention were produced.
[0025]
For comparison purposes, the above-mentioned end mill cemented carbide substrate was ultrasonically cleaned in acetone and dried, and charged into a normal arc ion plating apparatus shown in FIG. A hard coating layer composed of a (Ti, Al, R) N layer having the target composition and target layer thickness shown in Table 8 and having substantially no composition change along the layer thickness direction. by depositing, conventionally coated conventional surface-coated cemented carbide end mill of the cemented carbide (hereinafter, referred to as conventional coated cemented carbide end mills) 1-7 was produced, respectively.
[0026]
Next, of the present invention coated carbide end mills 1-7 and conventional coated carbide end mills 1-7 , the present invention coated carbide end mills 1-3 and conventional coated carbide end mills 1-3 are as follows:
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / FC200 plate material,
Cutting speed: 350 m / min,
Axial cut: 5mm,
Radial notch: 0.7mm,
Table feed: 2200 mm / min,
With respect to the cast iron wet high-speed high-feed side cutting test, the coated carbide end mills 4 and 5 according to the present invention and the conventional coated carbide end mills 4 and 5 ,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / SS400 plate material,
Cutting speed: 350 m / min,
Axial cut: 7mm,
Radial notch: 1mm,
Table feed: 2050 mm / min,
For the wet high speed high feed side cutting test of mild steel under the following conditions, the coated carbide end mills 6 and 7 of the present invention and the conventional coated carbide end mills 6 and 7 :
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / S20C plate material,
Cutting speed: 335 m / min,
Axial cut: 12mm,
Radial notch: 1.5mm,
Table feed: 1550 mm / min,
Wet high-speed high-feed side cutting test of carbon steel under the above conditions, and the flank wear width of the outer peripheral edge of the cutting edge is an indication 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 7 and 8 , respectively.
[0027]
[Table 6]

[0028]
[Table 7]

[0029]
[Table 8]

[0030]
(Example 3)
From the round bar sintered bodies C-1 to C-7 among the three types of round bar sintered bodies having diameters of 8 mm, 13 mm, and 26 mm manufactured in Example 2 above, this round bar sintered body was used. In the grinding process, in the combinations shown in Table 6, the diameter x length of the groove forming part has dimensions of 4 mm x 13 mm, 8 mm x 22 mm, and 16 mm x 45 mm, respectively, and the twist angle is 30 degrees. Drilled carbide substrates each having a two-blade shape were manufactured.
[0031]
Next, honing is performed on the cutting blades of these drill carbide substrates , ultrasonic cleaning in acetone is performed, and the dried state is inserted into the arc ion plating apparatus shown in FIG. The highest Al content point and the highest Ti content point of the target composition shown in Table 9 along the layer thickness direction are alternately repeated at the target interval shown in Table 9 , and the highest Al content. It has a component concentration distribution structure in which the Al and Ti contents continuously change from the content point to the Ti highest content point and from the Ti highest content point to the Al highest content point, respectively, and the whole target shown in Table 9 By vapor-depositing a hard coating layer having a layer thickness, drills made of the surface coated cemented carbide of the present invention (hereinafter referred to as the present coated carbide drill) 1 to 7 as the coated carbide tool of the present invention were produced.
[0032]
Further, for the purpose of comparison, the cutting edge of the above-mentioned drill cemented carbide substrate is subjected to honing, ultrasonically cleaned in acetone, and dried, and then mounted on the ordinary arc ion plating apparatus shown in FIG. And under the same conditions as in Example 1, the target composition and the target layer thickness shown in Table 10 and substantially no composition change along the layer thickness direction (Ti, Al, R) N By vapor-depositing a hard coating layer composed of layers, conventional surface-coated cemented carbide drills (hereinafter referred to as conventional coated carbide drills) 1 to 7 as conventional coated carbide tools were produced, respectively.
[0033]
Next, of the present invention coated carbide drills 1-7 and conventional coated carbide drills 1-7 , the present invention coated carbide drills 1-3 and conventional coated carbide drills 1-3 are as follows:
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / SS400 plate material,
Cutting speed: 235 m / min,
Feed: 0.52mm / rev,
Hole depth: 10mm
About the wet high speed high feed drilling test of mild steel under the conditions of the present invention, the coated carbide drills 4-6 of the present invention and the conventional coated carbide drills 4-6,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / S20C plate material,
Cutting speed: 245 m / min,
Feed: 0.58mm / rev,
Hole depth: 15mm
For the wet high-speed high-feed drilling test of carbon steel under the conditions of the present invention, the coated carbide drill 7 of the present invention and the conventional coated carbide drill 7 ,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS / FC200 plate material,
Cutting speed: 255 m / min,
Feed: 0.61 mm / rev,
Hole depth: 28mm
We performed a high-speed, high-feed, high-feed drilling test of cast iron under the above conditions, and in any wet drilling test (using water-soluble cutting oil), the flank wear width of the tip cutting edge surface reached 0.3 mm The number of holes drilled was measured. The measurement results are shown in Tables 9 and 10 , respectively.
[0034]
[Table 9]

[0035]
[Table 10]

[0036]
In the hard coating layer which comprises this invention coated carbide tip 1-15 as this invention coated carbide tool obtained as a result, this invention coated carbide end mill 1-7 , and this invention coated carbide drill 1-7 Composition of Al highest content point and Ti highest content point, and conventionally coated carbide tips 1-15 as conventionally coated carbide tools, conventionally coated carbide end mills 1-7 , and hard coating of conventionally coated carbide drills 1-7 The composition of the layers was measured using an Auger spectroscopic analyzer, and each showed substantially the same composition as the target composition.
Further, the distance between the Al highest content point and the Ti highest content point in the hard coating layer of these coated carbide tools 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 showed substantially the same value as the target value.
[0037]
【The invention's effect】
From the results shown in Tables 3 to 10 , the hard coating layer has predetermined high Al content points having excellent high temperature hardness and heat resistance and Ti maximum content points having high strength and toughness alternately in the layer thickness direction. A component concentration distribution structure that repeatedly exists at intervals, and 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. Each of the coated carbide tools of the present invention has various kinds of cutting work such as 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. Even in this case, the hard coating layer exhibits excellent wear resistance without occurrence of chipping, whereas the hard coating layer has substantially no composition change along the thickness direction (Ti, Al, R). Conventional coating consisting of N layers In a hard tool, the high-speed heavy cutting conditions described above cause rapid wear progress and chipping due to high-temperature hardness and insufficient heat resistance of the hard coating layer, and insufficient strength and toughness. It is clear that the service life is reached in a short time.
As described above, the coated carbide tool of the present invention is capable of cutting various types of steel and cast iron as well as cutting under normal conditions, particularly high-speed heavy cutting with high heat generation and high mechanical impact. Even when performed under conditions, chipping does not occur and excellent wear resistance is exhibited, so that it is possible to satisfactorily cope with labor saving and energy saving of cutting work and cost reduction.
[Brief description of the drawings]
FIG. 1 shows an arc ion plating apparatus used to form a hard coating layer constituting a coated carbide tool of the present invention, wherein (a) is a schematic plan view and (b) is a schematic front view.
FIG. 2 is a schematic explanatory view of a normal arc ion plating apparatus used to form a hard coating layer constituting a conventional coated carbide tool.

Claims

装置中央部に炭化タングステン基超硬合金基体および炭窒化チタン系サーメット基体のいずれか、または両方の装着用回転テーブルを設け、前記回転テーブルを挟んで、一方側にＡｌ最高含有点形成用Ａｌ−Ｔｉ−イットリウムを含まない希土類金属（以下、Ｒで示す）合金、他方側にＴｉ最高含有点形成用Ｔｉ−Ａｌ−Ｒ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複数の前記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、前記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、前記基体の表面に、ＡｌとＴｉとＲの複合窒化物層からなる硬質被覆層を１〜１５μｍの全体平均層厚で蒸着してなる表面被覆超硬合金製切削工具にして、
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_ＸＲ_Ｚ］Ｎ（ただし、原子比で、Ｘは０．０５〜０．３０、Ｚは０．００５〜０．１を示す）、
上記Ｔｉ最高含有点が、組成式：［Ｔｉ_1-( _Ｍ ₊ _Ｚ ₎Ａｌ_ＭＲ_Ｚ］Ｎ（ただし、原子比で、Ｍは０．０５〜０．３０、Ｚは０．００５〜０．１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であること、
を特徴とする高速重切削条件で硬質被覆層がすぐれた耐摩耗性を発揮する表面被覆超硬合金製切削工具。 A rotating table for mounting either or both of a tungsten carbide base cemented carbide substrate and a titanium carbonitride-based cermet substrate is provided at the center of the apparatus, and Al— An arc ion plating apparatus in which a rare earth metal (hereinafter referred to as R) alloy that does not contain Ti-yttrium and a Ti-Al-R alloy for forming the highest Ti content point on the other side is disposed as a cathode electrode (evaporation source) is used. In addition, a plurality of the bases are mounted in a ring shape at a predetermined distance in the radial direction from the central axis on the rotary table of the apparatus, and the rotary table is rotated with the atmosphere in the apparatus being a nitrogen atmosphere in this state, While rotating the substrate itself, an arc discharge is generated between the cathode electrode (evaporation source) and the anode electrode on both sides, and the front On the surface of the substrate, and a hard coating layer made of a composite nitride layer of Al, Ti, and R in total average layer surface-coated cemented carbide cutting tool comprising depositing a thickness of 1 to 15 m,
In the hard coating layer, the highest Al content point and the highest Ti content point are repeatedly present at predetermined intervals along the layer thickness direction, and the highest Ti content point, the highest Ti content point, and the highest Ti content point 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, respectively,
Furthermore, the Al highest content point is the composition formula: [Al _{1- (} _X ₊ _Z ₎ Ti _X R _Z ] N (wherein X is 0.05 to 0.30 and Z is 0.005 to 0.005 in atomic ratio). 0.1)
The Ti maximum content point, composition _{_{_{_{formula: [Ti 1- (M + Z}}}} ) Al M R Z] N ( provided that an atomic ratio, M is 0.05 to 0.30, Z is from 0.005 to 0. 1),
The distance between the Al highest content point and the Ti highest content point adjacent to each other is 0.01 to 0.1 μm,
A surface-coated cemented carbide cutting tool that exhibits excellent wear resistance under high-speed heavy cutting conditions.