JP2004090182A - Cutting tool made from surface coated cemented carbide for exhibiting high chipping resistance with hard coating layer in high-speed deep cut condition - Google Patents
Cutting tool made from surface coated cemented carbide for exhibiting high chipping resistance with hard coating layer in high-speed deep cut condition Download PDFInfo
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【０００１】
【発明の属する技術分野】
この発明は、硬質被覆層が高強度を有し、かつ高温硬さと耐熱性にもすぐれ、したがって特に各種の鋼や鋳鉄などの高速切削加工を、高い熱的機械的衝撃を伴う高切り込みや高送りなどの重切削条件で行なった場合にも、硬質被覆層がすぐれた耐チッピング性を示し、長期に亘ってすぐれた耐摩耗性を発揮する表面被覆超硬合金製切削工具（以下、被覆超硬工具という）に関するものである。
【０００２】
【従来の技術】
一般に、被覆超硬工具には、各種の鋼や鋳鉄などの被削材の旋削加工や平削り加工にバイトの先端部に着脱自在に取り付けて用いられるスローアウエイチップ、穴あけ切削加工などに用いられるドリルやミニチュアドリル、さらに面削加工や溝加工、肩加工などに用いられるソリッドタイプのエンドミルなどがあり、また前記スローアウエイチップを着脱自在に取り付けて前記ソリッドタイプのエンドミルと同様に切削加工を行うスローアウエイエンドミル工具などが知られている。
【０００３】
また、被覆超硬工具として、炭化タングステン（以下、ＷＣで示す）基超硬合金または炭窒化チタン（以下、ＴｉＣＮで示す）基サーメットからなる基体（以下、これらを総称して超硬基体と云う）の表面に、個々の層厚が１μｍ以下のＺｒ酸化物（以下、ＺｒＯ２で示す）層とＴｉ炭窒化物（以下、ＴｉＣＮで示す）層とを交互積層して、２〜２０μｍの全体平均層厚で蒸着してなる被覆超硬工具が提案され、前記硬質被覆層を構成するＺｒＯ２−ＴｉＣＮ交互積層が、ＺｒＯ２層による高温硬さおよび耐熱性と、ＴｉＣＮ層による強度を具備することから、かかる被覆超硬工具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、上記の被覆超硬工具が、例えば図１に概略縦断面図で示される通り、中央部にステンレス鋼製の反応ガス吹き出し管が立設され、前記反応ガス吹き出し管には、図２（ａ）に概略斜視図で、同（ｂ）に概略平面図で例示される黒鉛製の超硬基体支持パレットが串刺し積層嵌着され、かつこれらがステンレス鋼製のカバーを介してヒーターで加熱される構造を有する化学蒸着装置を用い、超硬基体を前記超硬基体支持パレットの底面に形成された多数の反応ガス通過穴位置に図示される通りに載置した状態で前記化学蒸着装置に装入し、ヒータで装置内を、例えば８００〜１１００℃の範囲内の所定の温度に加熱した後、ＺｒＯ２層形成には、反応ガスとして、容量％で（以下、反応ガスの％は容量％を示す）、
ＺｒＣｌ４：１〜３％、
ＣＯ２：７．５〜１１．５％、
ＨＣｌ：７．２〜１１．２％、
Ｈ２：残り、
からなる組成を有する反応ガスを用い、また、ＴｉＣＮ層形成には、
ＴｉＣｌ４：１〜３％、
ＣＨ４：１１〜１５％、
Ｎ２：４０〜６０％、
Ｈ２：残り、
からなる組成を有する反応ガスを用い、これらの反応ガスを予め真空排気された装置内に前記反応ガス吹き出し管を通して、装置内の反応ガス圧力を７〜４０ｋＰａの範囲内の所定の圧力に保持しながら、交互に導入することによりＺｒＯ２−ＴｉＣＮ交互積層からなる硬質被覆層を形成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】
特開昭５５−１４５１６５号公報
【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は強く、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、これを高い熱的機械的衝撃を伴う高切り込みや高送りなどの重切削を高速で行なうのに用いると、特にＺｒＯ２−ＴｉＣＮ交互積層からなる硬質被覆層のＺｒＯ２層はすぐれた高温硬さおよび耐熱性を有するものの強度が不十分であるために、高速重切削ではこれが破壊の起点となることから、チッピング（微小割れ）発生の原因となり、また同じくＴｉＣＮ層は高強度を有するものの高温硬さおよび耐熱性の低いものであることから、高速重切削では摩耗進行が急速に促進されるようになり、この結果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で硬質被覆層がすぐれた耐チッピング性を示し、長期に亘って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、研究を行った結果、
（ａ）上記の図１，２に示される化学蒸着装置を用いて、上記の従来被覆超硬工具の硬質被覆層の構成成分であるＺｒＯ２とＴｉＣＮの複合化合物、すなわちＺｒとＴｉの複合炭窒酸化物（以下、Ｚｒ−Ｔｉ炭窒酸化物という）層を形成するに際して、例えば図３に反応ガス組成自動制御システムが概略チャート図で示される通り、反応ガス組成および流量中央制御装置に、前記Ｚｒ−Ｔｉ炭窒酸化物層からなる硬質被覆層に、層厚方向にそって、Ｚｒおよび酸素の最高含有点と、Ｔｉ、炭素、および窒素の最高含有点とを所定間隔をおいて交互に繰り返し形成させる目的で、前記Ｚｒおよび酸素の最高含有点、並びにＴｉ、炭素、および窒素の最高含有点に対応した反応ガス組成、並びに前記両点間のＺｒと酸素、およびＴｉと炭素と窒素の連続変化に対応した反応ガス組成、さらに前記両点間の間隔を、過去の実績データに基づいてインプットし、この反応ガス組成および流量中央制御装置からの制御信号にしたがって、原料ガスボンベからのＨ２ガス、ＣＯ２ガス、ＣＨ４ガス、Ｎ２ガス、ＣＨ３ＣＮガス、およびＨＣｌガスの流量、さらにＺｒＣｌ４ガスおよびＴｉＣｌ４ガスの流量をそれぞれの原料ガス流量自動制御装置にて制御しながら、化学蒸着装置の反応ガス吹き出し管に導入すると、層厚方向にそって、Ｚｒおよび酸素の最高含有点と、Ｔｉ、炭素、および窒素の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Ｚｒおよび酸素の最高含有点から前記Ｔｉ、炭素、および窒素の最高含有点、前記Ｔｉ、炭素、および窒素の最高含有点から前記Ｚｒおよび酸素の最高含有点へＺｒと酸素、およびＴｉと炭素と窒素の含有量が連続的に変化する成分濃度分布構造をもつたＺｒ−Ｔｉ炭窒酸化物層からなる硬質被覆層が形成されるようになること。
【０００８】
（ｂ）上記（ａ）の繰り返し連続変化成分濃度分布構造のＺｒ−Ｔｉ炭窒酸化物層において、
上記Ｚｒおよび酸素の最高含有点におけるＺｒとＴｉ、および酸素と炭素と窒素の相互含有割合を示すＺｒ／（Ｚｒ＋Ｔｉ）、並びに酸素／（酸素＋炭素＋窒素）、炭素／（酸素＋炭素＋窒素）、および窒素／（酸素＋炭素＋窒素）が、それぞれ原子比で、
Ｚｒ／（Ｚｒ＋Ｔｉ）：０．８０〜０．９８、
酸素／（酸素＋炭素＋窒素）：０．８０〜０．９８、
炭素／（酸素＋炭素＋窒素）：０．０１〜０．１０、
窒素／（酸素＋炭素＋窒素）：０．０１〜０．１０、
上記Ｔｉ、炭素、および窒素の最高含有点におけるＴｉとＺｒ、および炭素と窒素と酸素の相互含有割合を示すＴｉ／（Ｔｉ＋Ｚｒ）、並びに炭素／（炭素＋窒素＋酸素）、窒素／（炭素＋窒素＋酸素）、および酸素／（炭素＋窒素＋酸素）が、それぞれ原子比で、
Ｔｉ／（Ｔｉ＋Ｚｒ）：０．８０〜０．９８、
炭素／（炭素＋窒素＋酸素）：０．４０〜０．４９、
窒素／（炭素＋窒素＋酸素）：０．４０〜０．４９、
酸素／（炭素＋窒素＋酸素）：０．０２〜０．２０、
とし、かつ隣り合う上記Ｚｒおよび酸素の最高含有点と、上記Ｔｉ、炭素、および窒素の最高含有点の厚さ方向の間隔を０．０１〜０．２μｍとすると、
上記Ｚｒおよび酸素の最高含有点部分では、ＺｒＯ２のもつ高温硬さと耐熱性に相当するすぐれた高温硬さと耐熱性を示し、一方上記Ｔｉ、炭素、および窒素の最高含有点部分では、ＴｉＣＮのもつ強度に相当する高強度が確保され、かつこれらＺｒおよび酸素の最高含有点と、上記Ｔｉ、炭素、および窒素の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すぐれた高温硬さと耐熱性、および高強度を具備するようになり、さらに前記両点間でＺｒと酸素、およびＴｉと炭素と窒素の含有量が連続的に変化（成分濃度分布構造）することにより、破壊の起点が存在しないことになり、したがって、硬質被覆層がかかる構成のＺｒ−Ｔｉ炭窒酸化物層からなる被覆超硬工具は、特に各種の鋼や鋳鉄などの切削加工を、高速で、かつ高い熱的機械的衝撃を伴う高切り込みや高送りなどの重切削条件で行なった場合にも、硬質被覆層がすぐれた耐チッピング性を示し、長期に亘って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、超硬基体の表面に、Ｚｒ−Ｔｉ炭窒酸化物層からなる硬質被覆層を２〜２０μｍの全体平均層厚で蒸着してなる被覆超硬工具において、
上記硬質被覆層が、層厚方向にそって、Ｚｒおよび酸素の最高含有点と、Ｔｉ、炭素、および窒素の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Ｚｒおよび酸素の最高含有点から前記Ｔｉ、炭素、および窒素の最高含有点、前記Ｔｉ、炭素、および窒素の最高含有点から前記Ｚｒおよび酸素の最高含有点へＺｒと酸素、およびＴｉと炭素と窒素の含有量が連続的に変化する成分濃度分布構造を有し、
さらに、上記Ｚｒおよび酸素の最高含有点におけるＺｒとＴｉ、および酸素と炭素と窒素の相互含有割合を示すＺｒ／（Ｚｒ＋Ｔｉ）、並びに酸素／（酸素＋炭素＋窒素）、炭素／（酸素＋炭素＋窒素）、および窒素／（酸素＋炭素＋窒素）が、それぞれ原子比で、
Ｚｒ／（Ｚｒ＋Ｔｉ）：０．８０〜０．９８、
酸素／（酸素＋炭素＋窒素）：０．８０〜０．９８、
炭素／（酸素＋炭素＋窒素）：０．０１〜０．１０、
窒素／（酸素＋炭素＋窒素）：０．０１〜０．１０、
上記Ｔｉ、炭素、および窒素の最高含有点におけるＴｉとＺｒ、および炭素と窒素と酸素の相互含有割合を示すＴｉ／（Ｔｉ＋Ｚｒ）、並びに炭素／（炭素＋窒素＋酸素）、窒素／（炭素＋窒素＋酸素）、および酸素／（炭素＋窒素＋酸素）が、それぞれ原子比で、
Ｔｉ／（Ｔｉ＋Ｚｒ）：０．８０〜０．９８、
炭素／（炭素＋窒素＋酸素）：０．４０〜０．４９、
窒素／（炭素＋窒素＋酸素）：０．４０〜０．４９、
酸素／（炭素＋窒素＋酸素）：０．０２〜０．２０、
を満足し、かつ隣り合う上記Ｚｒおよび酸素の最高含有点と、上記Ｔｉ、炭素、および窒素の最高含有点の間隔が、０．０１〜０．２μｍである、
高速重切削条件で硬質被覆層がすぐれた耐チッピング性を発揮する被覆超硬工具に特徴を有するものである。
【００１０】
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）Ｚｒおよび酸素の最高含有点
Ｚｒ−Ｔｉ炭窒酸化物層のＴｉ、炭素、および窒素成分には強度を向上させ、同Ｚｒおよび酸素成分には高温硬さおよび耐熱性を向上させる作用があり、したがってＺｒおよび酸素の最高含有点ではＺｒおよび酸素の含有割合を相対的に高くして高温硬さおよび耐熱性を向上させることにより、高熱発生を伴う高速切削に適合するものとするが、この場合ＺｒとＴｉ、および酸素と炭素と窒素の相互含有割合を示すＺｒ／（Ｚｒ＋Ｔｉ）値、および酸素／（酸素＋炭素＋窒素）値がいずれも原子比で（以下、同じ）０．９８を越えると、Ｔｉ／（Ｔｉ＋Ｚｒ）値：０．０２未満、並びに炭素／（酸素＋炭素＋窒素）値および窒素／（酸素＋炭素＋窒素）値がいずれも０．０１未満となってしまい、実質的にＺｒ酸化物で構成されるようになることから、高強度を有するＴｉと炭素と窒素の最高含有点が隣接して存在しても層自体の強度の低下は避けられず、この結果チッピングなどが発生し易くなり、一方同値がそれぞれ０．８０未満になると、Ｔｉ／（Ｔｉ＋Ｚｒ）値が０．２０を越え、かつ炭素／（酸素＋炭素＋窒素）値および窒素／（酸素＋炭素＋窒素）値がいずれも０．１０を越えて高くなり、反面相対的にＺｒおよび酸素の割合が少なくなり、この結果高温硬さおよび耐熱性が急激に低下し、摩耗促進の原因となることから、Ｚｒ／（Ｚｒ＋Ｔｉ）、および酸素／（酸素＋炭素＋窒素）の値をいずれも０．８０〜０．９８、炭素／（酸素＋炭素＋窒素）および窒素／（酸素＋炭素＋窒素）の値をいずれも０．０１〜０．１０と定めた。
【００１１】
（ｂ）Ｔｉ、炭素、および窒素の最高含有点
上記の通りＺｒおよび酸素の最高含有点は相対的にすぐれた高温硬さおよび耐熱性を有するが、反面相対的に強度が不十分であるため、このＺｒおよび酸素の最高含有点の強度不足を補う目的で、高強度を有するＴｉ、炭素、および窒素の最高含有点を厚さ方向に交互に介在させるものである。しかし、ＴｉとＺｒ、および炭素と窒素と酸素の相互含有割合を示すＴｉ／（Ｔｉ＋Ｚｒ）値が０．９８を越え、かつ炭素／（酸素＋炭素＋窒素）値および窒素／（酸素＋炭素＋窒素）値が、いずれも０．４９を越えると、Ｚｒ値が０．０２未満、並びに酸素／（炭素＋窒素＋酸素）値が０．０２未満となってしまい、実質的にＴｉ炭窒化物で構成されるようになることから、Ｔｉ、炭素、および窒素の最高含有点に所定の高温硬さおよび耐熱性を確保することができず、これが摩耗促進の原因となり、一方Ｔｉ／（Ｔｉ＋Ｚｒ）値が０．８０未満、炭素／（炭素＋窒素＋酸素）値および窒素／（炭素＋窒素＋酸素）値がいずれも０．４０未満になると、Ｚｒ／（Ｚｒ＋Ｔｉ）値が０．２０を越え、かつ酸素／（炭素＋窒素＋酸素）値が０．２０を越えて高くなり、相対的にＴｉ、炭素、および窒素の割合が少なくなって、所望の強度を確保することができず、この結果チッピングが発生し易くなることから、Ｔｉ／（Ｔｉ＋Ｚｒ）の値を０．８０〜０．９８、炭素／（炭素＋窒素＋酸素）および窒素／（炭素＋窒素＋酸素）の値をいずれも０．４０〜０．４９、酸素／（炭素＋窒素＋酸素）の値を０．０２〜０．２０と定めた。
【００１２】
（ｃ）Ｚｒおよび酸素の最高含有点と、Ｔｉ、炭素、および窒素の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すぐれた高温硬さおよび耐熱性、さらに高強度を確保することができなくなり、またその間隔が０．２μｍを越えるとそれぞれの点がもつ欠点、すなわちＺｒおよび酸素の最高含有点であれば強度不足、Ｔｉ、炭素、および窒素の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０．０１〜０．２μｍと定めた。
【００１３】
（ｄ）硬質被覆層の全体平均層厚
その層厚が２μｍ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２０μｍ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２〜２０μｍと定めた。
【００１４】
【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。
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、Ｃｒ３ Ｃ２ 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・ＣＮＭＧ１６０６０８のチップ形状をもったＷＣ基超硬合金製の超硬基体Ａ１〜Ａ１０を形成した。
【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、Ｍｏ２ Ｃ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・ＣＮＭＧ１６０６１２のチップ形状をもったＴｉＣＮ系サーメット製の超硬基体Ｂ１〜Ｂ６を形成した。
【００１６】
つぎに、上記の超硬基体Ａ１〜Ａ１０およびＢ１〜Ｂ６のそれぞれを、アセトン中で超音波洗浄し、乾燥した後、図１に示される化学蒸着装置内に、第２図に示される超硬基体支持パレットの位置決め穴に載置した状態で装入し、まず、装置内をヒーターで９００℃に加熱したところで、ＴｉＣｌ４：４．２％、Ｎ２：３０％、Ｈ２：残りからなる組成を有する反応ガスを反応ガス吹き出し管を通して導入して、装置内の反応雰囲気圧力を３０ｋＰａとし、この状態で３０分間保持して下地密着層として０．３μｍの平均層厚をもった窒化チタン（ＴｉＮ）層を形成し、ついで、同じく装置内の雰囲気温度をヒーターにて加熱して１０２０℃とした後、図３に示される反応ガス組成自動制御システムの反応ガス組成および流量中央制御装置に、過去の実績データにしたがって、表３、４に示されるＺｒおよび酸素の最高含有点の目標Ｚｒ／（Ｚｒ＋Ｔｉ）、並びに目標酸素／（酸素＋炭素＋窒素）、目標炭素／（酸素＋炭素＋窒素）、および目標窒素／（酸素＋炭素＋窒素）、さらにＴｉ、炭素、および窒素の最高含有点の目標Ｔｉ／（Ｔｉ＋Ｚｒ）、並びに目標炭素／（炭素＋窒素＋酸素）、目標窒素／（炭素＋窒素＋酸素）、および目標酸素／（炭素＋窒素＋酸素）に対応する反応ガス組成、前記Ｚｒおよび酸素の最高含有点と、Ｔｉ、炭素、および窒素の最高含有点間のＺｒと酸素、およびＴｉと炭素と窒素の含有量の連続変化に対応する反応ガス組成、さらに表５、６に示される前記両点間の目標間隔および硬質被覆層の目標全体層厚をインプットし、この反応ガス組成および流量中央制御装置からの信号にしたがって作動するコントロールバルブ内蔵の原料ガス流量自動制御装置を通して、原料ガスであるＨ２ガス、ＣＨ４ガス、Ｎ２ガス、ＣＨ３ＣＮガス、ＣＯ２ガス、およびＨＣｌガス、さらにＺｒＣｌ４ガスおよびＴｉＣｌ４ガス（この場合、ＺｒＣｌ４ガスは、ＺｒＣｌ４ガス発生器で金属Ｚｒと流量制御されたＨＣｌガスを反応させることにより形成され、また、ＴｉＣｌ４ガスは、図示の通り流量制御されたＨ２ガスをキャリアガスとしてＴｉＣｌ４ガス発生器に送り、ここで液体から気化されたＴｉＣｌ４ガスと共に原料ガス流量自動制御装置に送られ、さらにＣＨ３ＣＮガスは、ＣＨ３ＣＮ気化器で液体のＣＨ３ＣＮを加熱してガス化したものが原料ガス流量自動制御装置に送られる）を、それぞれのガス流量を制御しながら、図１の化学蒸着装置の反応ガス吹き出し管から装置内に導入し（装置内の反応雰囲気圧力は常に７ｋＰａに保持される）、もって前記超硬基体の表面に、層厚方向に沿って表５、６に示される目標Ｚｒ／（Ｚｒ＋Ｔｉ）、並びに目標酸素／（酸素＋炭素＋窒素）、目標炭素／（酸素＋炭素＋窒素）、および目標窒素／（酸素＋炭素＋窒素）のＺｒおよび酸素の最高含有点と、目標Ｔｉ／（Ｔｉ＋Ｚｒ）、目標炭素／（炭素＋窒素＋酸素）、目標窒素／（炭素＋窒素＋酸素）、および目標酸素／（炭素＋窒素＋酸素）のＴｉ、炭素、および窒素の最高含有点とが交互に同じく表５、６に示される目標間隔で繰り返し存在し、かつ前記Ｚｒおよび酸素の最高含有点から前記Ｔｉ、炭素、および窒素の最高含有点、前記Ｔｉ、炭素、および窒素の最高含有点から前記Ｚｒおよび酸素の最高含有点へＺｒと酸素、およびＴｉと炭素と窒素の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５、６に示される目標全体層厚の硬質被覆層を蒸着することにより、本発明被覆超硬工具としての本発明表面被覆超硬合金製スローアウエイチップ（以下、本発明被覆超硬チップと云う）１〜１６をそれぞれ製造した。
【００１７】
また、比較の目的で、これら超硬基体Ａ１〜Ａ１０およびＢ１〜Ｂ６を、アセトン中で超音波洗浄し、乾燥した後、同じくそれぞれ図１，２に示される通常の化学蒸着装置に装入し、ＺｒＯ２層の形成条件を、
反応ガス組成：ＺｒＣｌ４：１．３％、ＣＯ２：１０．５％、ＨＣｌ：１０．２％、Ｈ２：残り、
反応雰囲気温度：１０２０℃、
反応雰囲気圧力：７ｋＰａ、
とし、また、ＴｉＣＮ層の形成条件を、
反応ガス組成：ＴｉＣｌ４：２．２％、ＣＨ４：１３％、Ｎ２：４５％、Ｈ２：残り、
反応雰囲気温度：１０２０℃、
反応雰囲気圧力：７ｋＰａ、
として、それぞれ表７、８に示される目標層厚のＺｒＯ２層およびＴｉＣＮ層の交互積層からなる硬質被覆層を、前記超硬基体Ａ１〜Ａ１０およびＢ１〜Ｂ６のそれぞれの表面に、同じく表７、８に示される目標全体層厚で蒸着することにより、従来被覆超硬工具としての従来表面被覆超硬合金製スローアウエイチップ（以下、従来被覆超硬チップと云う）１〜１６をそれぞれ製造した。
【００１８】
つぎに、上記本発明被覆超硬チップ１〜１６および従来被覆超硬チップ１〜１６について、これを工具鋼製バイトの先端部に固定治具にてネジ止めした状態で、
被削材：ＪＩＳ・ＳＣｒ４１５の丸棒、
切削速度：４５０ｍ／ｍｉｎ．、
切り込み：５．０ｍｍ、
送り：０．３ｍｍ／ｒｅｖ．、
切削時間：５分、
の条件での合金鋼の乾式連続高速高切り込み切削加工試験、
被削材：ＪＩＳ・Ｓ１５Ｃの長さ方向等間隔４本縦溝入り丸棒、
切削速度：５００ｍ／ｍｉｎ．、
切り込み：２．０ｍｍ、
送り：０．６ｍｍ／ｒｅｖ．、
切削時間：５分、
の条件での炭素鋼の乾式断続高速高送り切削加工試験、さらに、
被削材：ＪＩＳ・ＦＣ２５０の長さ方向等間隔４本縦溝入り丸棒、
切削速度：５００ｍ／ｍｉｎ．、
切り込み：６．０ｍｍ、
送り：０．２ｍｍ／ｒｅｖ．、
切削時間：５分、
の条件での鋳鉄の乾式断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５〜８に示した。
【００１９】
【表１】
【表２】
【表３】
【表４】
【表５】
【表６】
【表７】
【表８】
この結果得られた本発明被覆超硬チップ１〜１６および従来被覆超硬チップ１〜１６を構成する硬質被覆層について、厚さ方向に沿ってＺｒ、Ｔｉ、酸素、炭素、および窒素の含有量をオージェ分光分析装置を用いて測定し、この測定結果から各測定点におけるＺｒ／（Ｚｒ＋Ｔｉ）およびＴｉ／（Ｔｉ＋Ｚｒ）の値、さらに酸素／（酸素＋炭素＋窒素）、炭素／（酸素＋炭素＋窒素）、および窒素／（酸素＋炭素＋窒素）の値を算出したところ、本発明被覆超硬チップ１〜１６の硬質被覆層では、Ｚｒおよび酸素の最高含有点と、Ｔｉ、炭素、および窒素の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Ｚｒおよび酸素の最高含有点からＴｉ、炭素、および窒素の最高含有点、前記Ｔｉ、炭素、および窒素の最高含有点からＺｒおよび酸素の最高含有点へＺｒとＴｉ、および酸素と炭素と窒素の含有量が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、硬質被覆層の平均層厚も目標全体層厚と実質的に同じ値を示した。また、従来被覆超硬チップ１〜１６の硬質被覆層においても目標層厚と実質的に同じ平均層厚のＺｒＯ２層とＴｉＣＮ層とが交互に、かつ目標全体層厚と実質的に同じ平均層厚で形成されていることが確認された。
【００２８】
【発明の効果】
表５〜８に示される結果から、硬質被覆層が層厚方向に、相対的にすぐれた高温硬さと耐熱性を有するＺｒおよび酸素の最高含有点と，相対的に高強度を有するＴｉ、炭素、および窒素の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Ｚｒおよび酸素の最高含有点から前記Ｔｉ、炭素、および窒素の最高含有点、前記Ｔｉ、炭素、および窒素の最高含有点から前記Ｚｒおよび酸素の最高含有点へＺｒと酸素、およびＴｉと炭素と窒素の含有量が連続的に変化する成分濃度分布構造を有する本発明被覆超硬チップ１〜１６は、いずれも各種の鋼や鋳鉄などの切削加工を、高速で、かつ高い熱的機械的衝撃を伴う高切り込みや高送りなどの重切削条件で行なった場合にも、硬質被覆層がすぐれた耐チッピング性を示し、すぐれた耐摩耗性を発揮するのに対して、硬質被覆層がＺｒＯ２層とＴｉＣＮ層の交互積層からなる従来被覆超硬チップ１〜１６においては、前記硬質被覆層のＺｒＯ２層が特に高速重切削条件ではチッピング発生の起点となり、また前記ＴｉＣＮ層の摩耗進行が切削時の高熱発熱により促進されることから、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、高速で、かつ高い熱的機械的衝撃を伴う高切り込みや高送りなどの重切削条件で行なった場合にも、すぐれた耐チッピング性を示し、すぐれた耐摩耗性を長期に亘って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】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化学蒸着装置を例示する概略縦断面図である。
【図２】化学蒸着装置の構造部材である超硬基体支持パレットを示し、（ａ）が概略斜視図、（ｂ）が概略平面図である。
【図３】この発明の被覆超硬工具を構成する硬質被覆層の形成に用いられる反応ガス組成自動制御システムの概略チャート図である。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides a hard coating layer having high strength and excellent high-temperature hardness and heat resistance. Therefore, high-speed cutting of various steels and cast irons can be performed particularly at high cutting and high cutting rates with high thermal mechanical impact. Even when the cutting is performed under heavy cutting conditions such as feed, the hard coating layer exhibits excellent chipping resistance and exhibits a long-term excellent wear resistance. Hard tool).
[0002]
[Prior art]
In general, coated carbide tools are used for throw-away inserts, drilling, etc., which are removably attached to the tip of a cutting tool for turning or planing of various materials such as steel and cast iron. There are solid type end mills used for drilling and miniature drills, as well as for face milling, grooving, shoulder processing, etc., and the cutting is performed in the same manner as the solid type end mill by detachably attaching the throw-away tip. A throw-away end mill tool and the like are known.
[0003]
Further, as a coated cemented carbide tool, a substrate made of tungsten carbide (hereinafter, referred to as WC) -based cemented carbide or titanium carbonitride (hereinafter, referred to as TiCN) -based cermet (hereinafter, collectively referred to as a cemented carbide substrate) ), A Zr oxide (hereinafter referred to as ZrO 2 ) layer and a Ti carbonitride (hereinafter referred to as TiCN) layer each having a thickness of 1 μm or less are alternately laminated on the surface of A coated cemented carbide tool deposited with an average layer thickness has been proposed, and the ZrO 2 -TiCN alternating layer constituting the hard coating layer has high-temperature hardness and heat resistance by the ZrO 2 layer and strength by the TiCN layer. Therefore, it is also known that such coated carbide tools exhibit excellent cutting performance when used for continuous cutting or interrupted cutting of various types of steel, cast iron, and the like (for example, see Patent Document 1).
[0004]
Further, as shown in the schematic vertical sectional view of FIG. 1, for example, the above coated carbide tool is provided with a reaction gas blowing pipe made of stainless steel at the center thereof, and the reaction gas blowing pipe is provided with a reaction gas blowing pipe shown in FIG. Graphite carbide substrate support pallets exemplified in a schematic perspective view in a) and a schematic plan view in b) are skewered, stacked and fitted, and heated by a heater via a stainless steel cover. Using a chemical vapor deposition apparatus having a structure as shown in the figure, the cemented carbide substrate is mounted on the chemical vapor deposition apparatus in a state where it is placed as shown in a number of reaction gas passage holes formed on the bottom surface of the cemented carbide support pallet. Type, was heated in the apparatus with a heater, for example, to a predetermined temperature in the range of 800 to 1100 ° C., the ZrO 2 layer formed, as a reaction gas, by volume% (hereinafter,% of the reaction gas volume% ),
ZrCl 4 : 1-3%,
CO 2: 7.5~11.5%,
HCl: 7.2 to 11.2%,
H 2 : remaining,
A reactive gas having a composition consisting of:
TiCl 4: 1~3%,
CH 4: 11~15%,
N 2: 40~60%,
H 2 : remaining,
These reaction gases are passed through the reaction gas blow-out pipe into a device which has been evacuated in advance, and the reaction gas pressure in the device is maintained at a predetermined pressure within a range of 7 to 40 kPa. However, it is also known that it is manufactured by forming a hard coating layer composed of ZrO 2 —TiCN alternately laminated by alternately introducing (see Patent Document 1, for example).
[0005]
[Patent Document 1]
JP-A-55-145165
[Problems to be solved by the invention]
In recent years, the performance of cutting equipment has been remarkably improved, but on the other hand, there has been a strong demand for labor-saving and energy-saving cutting, as well as low cost. There is a tendency for cutting under heavy cutting conditions such as high feed, but in the above-mentioned conventional coated carbide tools, heavy cutting such as high cutting and high feed with high thermal mechanical impact is required. When used for high-speed cutting, the ZrO 2 layer of the hard coating layer composed of ZrO 2 —TiCN alternate lamination has excellent high-temperature hardness and heat resistance, but the strength is insufficient. Since it becomes a starting point of fracture, it causes the occurrence of chipping (micro cracking). Similarly, since the TiCN layer has high strength, it has low high-temperature hardness and low heat resistance. Wear progress fast heavy cutting is to be rapidly promoted, to reach this result relatively short time service life at present.
[0007]
[Means for Solving the Problems]
In view of the above, the present inventors have developed a coated cemented carbide tool in which a hard coating layer exhibits excellent chipping resistance particularly in high-speed heavy cutting, and exhibits excellent wear resistance over a long period of time. As a result of conducting research to develop,
(A) Using the chemical vapor deposition apparatus shown in FIGS. 1 and 2 above, a composite compound of ZrO 2 and TiCN, which is a component of the hard coating layer of the conventional coated carbide tool, that is, a composite carbon of Zr and Ti When forming a nitrogen oxide (hereinafter referred to as Zr-Ti carbonitride) layer, for example, as shown in a schematic chart of a reaction gas composition automatic control system in FIG. A maximum content point of Zr and oxygen and a maximum content point of Ti, carbon, and nitrogen are alternately arranged at predetermined intervals along a layer thickness direction on the hard coating layer made of the Zr-Ti carbonitride oxide layer. For the purpose of repeatedly forming a reaction gas composition corresponding to the highest content points of the Zr and oxygen, and the highest content points of Ti, carbon, and nitrogen, and Zr and oxygen between the two points, and Ti, carbon, and nitrogen The reaction gas composition corresponding to the continuous change of the pressure and the interval between the two points are input based on the past performance data, and the reaction gas composition and the H signal from the raw material gas cylinder are controlled in accordance with the control signal from the flow rate central controller. While controlling the flow rates of the 2 gas, CO 2 gas, CH 4 gas, N 2 gas, CH 3 CN gas, and HCl gas, and further, the flow rates of the ZrCl 4 gas and the TiCl 4 gas with the respective source gas flow automatic controllers, When introduced into the reaction gas blow-out tube of the chemical vapor deposition apparatus, the highest content points of Zr and oxygen and the highest content points of Ti, carbon, and nitrogen are alternately present at predetermined intervals along the layer thickness direction. And from the highest point of Zr and oxygen the highest point of Ti, carbon and nitrogen, and the highest point of Ti, carbon and nitrogen A hard coating layer composed of a Zr-Ti carbonitride layer having a component concentration distribution structure in which the contents of Zr and oxygen, and the contents of Ti, carbon and nitrogen continuously change to the highest content point of Zr and oxygen is formed. To be done.
[0008]
(B) In the Zr-Ti carbonitride layer of the above-mentioned (a) repeating and continuously changing component concentration distribution structure,
Zr / (Zr + Ti) indicating the mutual content ratio of Zr and Ti, and oxygen / carbon and nitrogen at the maximum content point of Zr and oxygen, and oxygen / (oxygen + carbon + nitrogen), carbon / (oxygen + carbon + nitrogen) ) And nitrogen / (oxygen + carbon + nitrogen) are each in atomic ratio,
Zr / (Zr + Ti): 0.80 to 0.98,
Oxygen / (oxygen + carbon + nitrogen): 0.80 to 0.98,
Carbon / (oxygen + carbon + nitrogen): 0.01 to 0.10,
Nitrogen / (oxygen + carbon + nitrogen): 0.01 to 0.10,
Ti / (Ti + Zr) indicating the mutual content ratio of Ti and Zr, and carbon / nitrogen / oxygen at the highest content points of Ti, carbon and nitrogen, and carbon / (carbon + nitrogen + oxygen) and nitrogen / (carbon + Nitrogen + oxygen) and oxygen / (carbon + nitrogen + oxygen)
Ti / (Ti + Zr): 0.80 to 0.98,
Carbon / (carbon + nitrogen + oxygen): 0.40 to 0.49,
Nitrogen / (carbon + nitrogen + oxygen): 0.40 to 0.49,
Oxygen / (carbon + nitrogen + oxygen): 0.02 to 0.20,
And the distance between the highest Zr and oxygen content points and the highest Ti, carbon, and nitrogen content points in the thickness direction is 0.01 to 0.2 μm,
The highest Zr and oxygen content points show excellent high temperature hardness and heat resistance corresponding to the high temperature hardness and heat resistance of ZrO 2 , while the highest Ti, carbon, and nitrogen content points show TiCN A high strength corresponding to the strength of the layer is secured, and the interval between the maximum content points of Zr and oxygen and the maximum content points of Ti, carbon, and nitrogen are extremely small. Hardness, heat resistance, and high strength are provided, and further, the contents of Zr and oxygen, and Ti, carbon, and nitrogen are continuously changed (component concentration distribution structure) between the above two points, so that destruction is caused. Therefore, the coated carbide tool made of the Zr—Ti carbonitride layer having the hard coating layer in the above-described manner is particularly suitable for cutting various kinds of steel and cast iron. The hard coating layer shows excellent chipping resistance even under heavy cutting conditions such as high cutting and high feed with high speed and high thermal mechanical impact, and excellent wear resistance over a long period of time To demonstrate.
The research results shown in (a) and (b) above were obtained.
[0009]
The present invention has been made on the basis of the above research results, and a hard coating layer composed of a Zr-Ti carbonitride layer is deposited on the surface of a super-hard substrate with a total average layer thickness of 2 to 20 μm. Coated carbide tools,
In the hard coating layer, the highest content points of Zr and oxygen and the highest content points of Ti, carbon, and nitrogen are alternately and repeatedly provided at predetermined intervals along the layer thickness direction, and the Zr and oxygen From the highest content point of Ti, carbon, and nitrogen to the highest content point of Ti, carbon, and nitrogen to the highest content point of Zr and oxygen, and the content of Ti, carbon, and nitrogen Having a component concentration distribution structure in which the amount changes continuously,
Further, Zr / (Zr + Ti) indicating the mutual content ratio of Zr and Ti, and oxygen / carbon and nitrogen at the highest content points of Zr and oxygen, oxygen / (oxygen + carbon + nitrogen), carbon / (oxygen + carbon + Nitrogen), and nitrogen / (oxygen + carbon + nitrogen) in atomic ratio,
Zr / (Zr + Ti): 0.80 to 0.98,
Oxygen / (oxygen + carbon + nitrogen): 0.80 to 0.98,
Carbon / (oxygen + carbon + nitrogen): 0.01 to 0.10,
Nitrogen / (oxygen + carbon + nitrogen): 0.01 to 0.10,
Ti / (Ti + Zr) indicating the mutual content ratio of Ti and Zr, and carbon / nitrogen / oxygen at the highest content points of Ti, carbon and nitrogen, and carbon / (carbon + nitrogen + oxygen) and nitrogen / (carbon + Nitrogen + oxygen) and oxygen / (carbon + nitrogen + oxygen)
Ti / (Ti + Zr): 0.80 to 0.98,
Carbon / (carbon + nitrogen + oxygen): 0.40 to 0.49,
Nitrogen / (carbon + nitrogen + oxygen): 0.40 to 0.49,
Oxygen / (carbon + nitrogen + oxygen): 0.02 to 0.20,
And the interval between the adjacent highest content points of Zr and oxygen and the highest content points of Ti, carbon, and nitrogen is 0.01 to 0.2 μm,
It is characterized by a coated carbide tool in which a hard coating layer exhibits excellent chipping resistance under high-speed heavy cutting conditions.
[0010]
Next, the reason why the configuration of the hard coating layer constituting the coated carbide tool of the present invention is limited as described above will be described.
(A) The highest content point of Zr and oxygen The effect of improving the strength for the Ti, carbon and nitrogen components of the Zr-Ti carbonitride layer and improving the high-temperature hardness and heat resistance for the Zr and oxygen components Therefore, at the highest content point of Zr and oxygen, by increasing the content ratio of Zr and oxygen relatively to improve high-temperature hardness and heat resistance, it is suitable for high-speed cutting with high heat generation. In this case, the Zr / (Zr + Ti) value and the oxygen / (oxygen + carbon + nitrogen) value, which indicate the mutual content ratio of Zr and Ti, and oxygen, carbon, and nitrogen, are all in atomic ratio (hereinafter the same). If it exceeds 98, the Ti / (Ti + Zr) value is less than 0.02, and the carbon / (oxygen + carbon + nitrogen) value and the nitrogen / (oxygen + carbon + nitrogen) value are both less than 0.01. , Virtually Since it is composed of r-oxide, even if the highest content points of Ti, carbon and nitrogen having high strength are present adjacent to each other, a decrease in the strength of the layer itself is inevitable, and as a result, chipping etc. When the values are less than 0.80, respectively, the Ti / (Ti + Zr) value exceeds 0.20, and the carbon / (oxygen + carbon + nitrogen) value and the nitrogen / (oxygen + carbon + nitrogen) value Both values are higher than 0.10, and the proportions of Zr and oxygen are relatively small. As a result, the high-temperature hardness and heat resistance are sharply reduced, which causes the acceleration of wear. / (Zr + Ti) and oxygen / (oxygen + carbon + nitrogen) are all 0.80 to 0.98, and carbon / (oxygen + carbon + nitrogen) and nitrogen / (oxygen + carbon + nitrogen) are all In each case, it was determined as 0.01 to 0.10.
[0011]
(B) Maximum content of Ti, carbon, and nitrogen As described above, the maximum content of Zr and oxygen has relatively excellent high-temperature hardness and heat resistance, but has relatively insufficient strength. In order to compensate for the lack of strength at the highest content points of Zr and oxygen, the highest content points of Ti, carbon and nitrogen having high strength are alternately interposed in the thickness direction. However, the value of Ti / (Ti + Zr), which indicates the mutual content of Ti and Zr, and the content of carbon, nitrogen and oxygen, exceeds 0.98, and the values of carbon / (oxygen + carbon + nitrogen) and nitrogen / (oxygen + carbon + If the nitrogen value exceeds 0.49, the Zr value is less than 0.02, and the oxygen / (carbon + nitrogen + oxygen) value is less than 0.02. , It is not possible to secure predetermined high-temperature hardness and heat resistance at the highest content points of Ti, carbon, and nitrogen, which causes abrasion acceleration, while Ti / (Ti + Zr) When the value is less than 0.80 and the carbon / (carbon + nitrogen + oxygen) value and the nitrogen / (carbon + nitrogen + oxygen) value are all less than 0.40, the Zr / (Zr + Ti) value exceeds 0.20. And the oxygen / (carbon + nitrogen + oxygen) value is 0. 0, and the ratios of Ti, carbon, and nitrogen become relatively small, and the desired strength cannot be secured. As a result, chipping is likely to occur, so that Ti / (Ti + Zr) Are 0.80 to 0.98, the values of carbon / (carbon + nitrogen + oxygen) and nitrogen / (carbon + nitrogen + oxygen) are 0.40 to 0.49, and the value of oxygen / (carbon + nitrogen + Oxygen) was determined to be 0.02 to 0.20.
[0012]
(C) Interval between the highest content point of Zr and oxygen and the highest content point of Ti, carbon, and nitrogen If the interval is less than 0.01 μm, it is difficult to clearly form each point with the above composition. As a result, it is not possible to ensure the desired excellent high-temperature hardness and heat resistance and high strength of the layer, and when the distance exceeds 0.2 μm, the disadvantages of the respective points, that is, the maximum of Zr and oxygen, At the content point, insufficient strength, and at the highest content point of Ti, carbon, and nitrogen, insufficient high-temperature hardness and heat resistance locally appear in the layer, which causes chipping or wear. Is promoted, the interval is set to 0.01 to 0.2 μm.
[0013]
(D) If the average thickness of the hard coating layer is less than 2 μm, the desired wear resistance cannot be ensured. On the other hand, if the average thickness exceeds 20 μm, chipping is likely to occur. Therefore, the average layer thickness was determined to be 2 to 20 μm.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, the coated cemented carbide tool of the present invention will be specifically described with reference to examples.
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 conditions of holding, after sintering, the cutting edge portion is subjected to honing processing of R: 0.03, and a carbide substrate A1 to A10 made of a WC-based cemented carbide having a chip shape of ISO standard CNMG160608. Was 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 CNMG160612. Carbide bases B1 to B6 made of TiCN-based cermet having the chip shape described above were formed.
[0016]
Next, each of the above-mentioned super-hard substrates A1 to A10 and B1 to B6 is subjected to ultrasonic cleaning in acetone, dried, and then placed in a chemical vapor deposition apparatus shown in FIG. It was loaded while being placed in the positioning holes of the substrate supporting pallet. First, when the inside of the apparatus was heated to 900 ° C. with a heater, TiCl 4 : 4.2%, N 2 : 30%, and H 2 : remainder. A reaction gas having a composition is introduced through a reaction gas blow-out tube, the reaction atmosphere pressure in the apparatus is set to 30 kPa, and this state is maintained for 30 minutes, and titanium nitride having an average layer thickness of 0.3 μm as a base adhesion layer ( After a TiN) layer was formed and the atmosphere temperature in the apparatus was also increased to 1020 ° C. by a heater, the reaction gas composition and flow rate central control device of the reaction gas composition automatic control system shown in FIG. According to the past performance data, the target Zr / (Zr + Ti) of the maximum content of Zr and oxygen shown in Tables 3 and 4, and the target oxygen / (oxygen + carbon + nitrogen), the target carbon / (oxygen + carbon) + Nitrogen), and target nitrogen / (oxygen + carbon + nitrogen), and also the target Ti / (Ti + Zr) of the highest content point of Ti, carbon, and nitrogen, and target carbon / (carbon + nitrogen + oxygen), target nitrogen / (Carbon + nitrogen + oxygen) and the reaction gas composition corresponding to the target oxygen / (carbon + nitrogen + oxygen), the maximum content of Zr and oxygen, and the Zr between the maximum content of Ti, carbon, and nitrogen. The reaction gas composition corresponding to the continuous change of the content of oxygen and Ti, carbon and nitrogen, the target interval between the two points shown in Tables 5 and 6, and the target total layer thickness of the hard coating layer were input. Reaction gas composition And a source gas H 2 gas, CH 4 gas, N 2 gas, CH 3 CN gas, CO 2 gas, and a source gas through a source gas flow automatic controller with a built-in control valve that operates according to a signal from the flow rate central controller. HCl gas, and further ZrCl 4 gas and TiCl 4 gas (in this case, the ZrCl 4 gas is formed by reacting a metal Zr with a flow-controlled HCl gas in a ZrCl 4 gas generator, and the TiCl 4 gas is As shown in the figure, the H 2 gas whose flow rate is controlled is sent to a TiCl 4 gas generator as a carrier gas, where it is sent together with the TiCl 4 gas vaporized from the liquid to a raw material gas flow automatic control device, and the CH 3 CN gas is CH 3 by heating the CH 3 CN in liquid CN vaporizer that gasified feedstock gas flow automatic control device Is introduced into the apparatus from the reaction gas blow-out pipe of the chemical vapor deposition apparatus shown in FIG. 1 while controlling the respective gas flow rates (the pressure of the reaction atmosphere in the apparatus is always kept at 7 kPa). On the surface of the substrate, target Zr / (Zr + Ti), target oxygen / (oxygen + carbon + nitrogen), target carbon / (oxygen + carbon + nitrogen), and target Zr / (Zr + Ti) shown in Tables 5 and 6 along the layer thickness direction. Nitrogen / (oxygen + carbon + nitrogen) Zr and oxygen maximum contents, target Ti / (Ti + Zr), target carbon / (carbon + nitrogen + oxygen), target nitrogen / (carbon + nitrogen + oxygen), and target The highest content points of oxygen / (carbon + nitrogen + oxygen) of Ti, carbon, and nitrogen are alternately present at the target intervals also shown in Tables 5 and 6, and from the highest content points of Zr and oxygen, Ti, carbon and nitrogen Component concentration distribution in which the contents of Zr and oxygen, and the contents of Ti, carbon and nitrogen continuously change from the highest content point of nitrogen, the highest content point of Ti, carbon and nitrogen to the highest content point of Zr and oxygen, respectively By depositing a hard coating layer having a structure and a target overall layer thickness also shown in Tables 5 and 6, a surface-coated cemented carbide alloy throw-away tip (hereinafter, referred to as a coated cemented carbide tool of the present invention) Inventive coated carbide tips) 1 to 16 were manufactured respectively.
[0017]
For the purpose of comparison, these super-hard substrates A1 to A10 and B1 to B6 were ultrasonically cleaned in acetone and dried, and then charged into the ordinary chemical vapor deposition apparatus shown in FIGS. , ZrO 2 layer forming conditions are as follows:
Reaction gas composition: ZrCl 4: 1.3%, CO 2: 10.5%, HCl: 10.2%, H 2: remainder,
Reaction atmosphere temperature: 1020 ° C,
Reaction atmosphere pressure: 7 kPa,
And the conditions for forming the TiCN layer are as follows:
Reaction gas composition: TiCl 4: 2.2%, CH 4: 13%, N 2: 45%, H 2: remainder,
Reaction atmosphere temperature: 1020 ° C,
Reaction atmosphere pressure: 7 kPa,
A hard coating layer composed of alternately laminated ZrO 2 layers and TiCN layers having the target layer thicknesses shown in Tables 7 and 8, respectively, was placed on the surfaces of the super-hard substrates A1 to A10 and B1 to B6, respectively. , 8 were produced, and the conventional surface coated cemented carbide throw-away tips (hereinafter referred to as conventionally coated cemented carbide tips) 1 to 16 as the conventionally coated cemented carbide tools were produced, respectively. .
[0018]
Next, with respect to the above-mentioned coated carbide tips 1 to 16 of the present invention and conventional coated carbide tips 1 to 16, in a state where they were screwed to the tip of a tool steel tool with a fixing jig,
Work material: JIS / SCr415 round bar,
Cutting speed: 450 m / min. ,
Cut: 5.0 mm,
Feed: 0.3 mm / rev. ,
Cutting time: 5 minutes,
Dry continuous high-speed high-cut cutting test of alloy steel under the conditions
Work material: JIS S15C lengthwise round bar
Cutting speed: 500 m / min. ,
Notch: 2.0 mm,
Feed: 0.6 mm / rev. ,
Cutting time: 5 minutes,
Intermittent high-speed high-feed cutting test of carbon steel under the conditions of
Work material: Round bar with four vertical grooves at equal intervals in the length direction of JIS FC250
Cutting speed: 500 m / min. ,
Cut: 6.0 mm,
Feed: 0.2 mm / rev. ,
Cutting time: 5 minutes,
A dry intermittent high-speed, high-cut cutting test was performed on cast iron under the following conditions, and the flank wear width of the cutting edge was measured in each cutting test. The measurement results are shown in Tables 5 to 8.
[0019]
[Table 1]
[Table 2]
[Table 3]
[Table 4]
[Table 5]
[Table 6]
[Table 7]
[Table 8]
Regarding the hard coating layers constituting the coated carbide tips 1-16 of the present invention and the conventional coated carbide tips 1-16 obtained as a result, the contents of Zr, Ti, oxygen, carbon, and nitrogen along the thickness direction Was measured using an Auger spectrometer. From the measurement results, the values of Zr / (Zr + Ti) and Ti / (Ti + Zr) at each measurement point, oxygen / (oxygen + carbon + nitrogen), and carbon / (oxygen + carbon) were obtained. + Nitrogen) and the value of nitrogen / (oxygen + carbon + nitrogen) were calculated. In the hard coating layers of the coated superhard tips 1 to 16 of the present invention, the highest content points of Zr and oxygen, Ti, carbon, and And the highest content point of nitrogen is alternately and repeatedly present at substantially the same composition and interval as the target value, and the highest content points of Ti, carbon, and nitrogen from the highest content points of Zr and oxygen; And from the highest content point of nitrogen to the highest content point of Zr and oxygen, it was confirmed that the content of Zr and Ti, and the content of oxygen, carbon and nitrogen continuously changed, and the average of the hard coating layer was The layer thickness also showed substantially the same value as the target overall layer thickness. Also, in the hard coating layers of the conventionally coated carbide tips 1 to 16, ZrO 2 layers and TiCN layers having substantially the same average layer thickness as the target layer thickness are alternately formed and have substantially the same average layer thickness as the target overall layer thickness. It was confirmed that the film was formed with a layer thickness.
[0028]
【The invention's effect】
The results shown in Tables 5 to 8 show that the hard coating layer has, in the layer thickness direction, the highest content points of Zr and oxygen having relatively excellent high-temperature hardness and heat resistance, and Ti and carbon having relatively high strength. , And the highest content point of nitrogen are repeatedly and alternately present at a predetermined interval, and the highest content point of Ti, carbon, and nitrogen, the highest content point of Ti, carbon, and nitrogen from the highest content point of Zr and oxygen. The coated carbide tips 1 to 16 of the present invention having a component concentration distribution structure in which the contents of Zr and oxygen, and the contents of Ti, carbon and nitrogen continuously change from the highest content point to the highest Zr and oxygen content points, The hard coating layer has excellent chipping resistance even when cutting various types of steel and cast iron at high speed and under heavy cutting conditions such as high cutting and high feed with high thermal and mechanical shock. Show, excellence Whereas exhibits wear resistance, in the conventional coated carbide inserts 1 through 16 hard layer is composed of alternate lamination of ZrO 2 layer and the TiCN layer, ZrO 2 layer of the hard coating layer is especially high speed heavy cutting Under the conditions, it becomes a starting point of the occurrence of chipping, and the wear progress of the TiCN layer is accelerated by high heat generation at the time of cutting.
As described above, the coated cemented carbide tool of the present invention not only cuts under normal conditions, but also cuts various kinds of steel and cast iron, etc., at high speed, and involves high thermal mechanical impact. Even when performed under heavy cutting conditions such as high depth of cut and high feed, it exhibits excellent chipping resistance and exhibits excellent wear resistance over a long period of time. In addition, it is possible to sufficiently satisfy cost reduction.
[Brief description of the drawings]
FIG. 1 is a schematic vertical sectional view illustrating a chemical vapor deposition apparatus used for forming a hard coating layer constituting a coated carbide tool.
FIGS. 2A and 2B show a super hard substrate supporting pallet as a structural member of the chemical vapor deposition apparatus, wherein FIG. 2A is a schematic perspective view and FIG. 2B is a schematic plan view.
FIG. 3 is a schematic chart of a reaction gas composition automatic control system used for forming a hard coating layer constituting the coated carbide tool of the present invention.
Claims (1)
上記硬質被覆層が、層厚方向にそって、Ｚｒおよび酸素の最高含有点と、Ｔｉ、炭素、および窒素の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Ｚｒおよび酸素の最高含有点から前記Ｔｉ、炭素、および窒素の最高含有点、前記Ｔｉ、炭素、および窒素の最高含有点から前記Ｚｒおよび酸素の最高含有点へＺｒと酸素、およびＴｉと炭素と窒素の含有量が連続的に変化する成分濃度分布構造を有し、
さらに、上記Ｚｒおよび酸素の最高含有点におけるＺｒとＴｉ、および酸素と炭素と窒素の相互含有割合を示すＺｒ／（Ｚｒ＋Ｔｉ）、並びに酸素／（酸素＋炭素＋窒素）、炭素／（酸素＋炭素＋窒素）、および窒素／（酸素＋炭素＋窒素）が、それぞれ原子比で、
Ｚｒ／（Ｚｒ＋Ｔｉ）：０．８０〜０．９８、
酸素／（酸素＋炭素＋窒素）：０．８０〜０．９８、
炭素／（酸素＋炭素＋窒素）：０．０１〜０．１０、
窒素／（酸素＋炭素＋窒素）：０．０１〜０．１０、
上記Ｔｉ、炭素、および窒素の最高含有点におけるＴｉとＺｒ、および炭素と窒素と酸素の相互含有割合を示すＴｉ／（Ｔｉ＋Ｚｒ）、並びに炭素／（炭素＋窒素＋酸素）、窒素／（炭素＋窒素＋酸素）、および酸素／（炭素＋窒素＋酸素）が、それぞれ原子比で、
Ｔｉ／（Ｔｉ＋Ｚｒ）：０．８０〜０．９８、
炭素／（炭素＋窒素＋酸素）：０．４０〜０．４９、
窒素／（炭素＋窒素＋酸素）：０．４０〜０．４９、
酸素／（炭素＋窒素＋酸素）：０．０２〜０．２０、
を満足し、かつ隣り合う上記Ｚｒおよび酸素の最高含有点と、上記Ｔｉ、炭素、および窒素の最高含有点の間隔が、０．０１〜０．２μｍであること、
を特徴とする高速重切削条件で硬質被覆層がすぐれた耐チッピング性を発揮する表面被覆超硬合金製切削工具。A surface coating layer formed by vapor-depositing a hard coating layer composed of a composite carbonitride oxide layer of Zr and Ti on the surface of a tungsten carbide-based cemented carbide substrate or a titanium carbonitride-based cermet substrate with a total average layer thickness of 2 to 20 μm. In hard alloy cutting tools,
In the hard coating layer, the highest content points of Zr and oxygen and the highest content points of Ti, carbon, and nitrogen are alternately and repeatedly provided at predetermined intervals along the layer thickness direction, and the Zr and oxygen From the highest content point of Ti to the highest content point of Ti, carbon, and nitrogen; from the highest content point of Ti, carbon, and nitrogen to the highest content point of the Zr and oxygen content of Zr and oxygen, and Ti, carbon, and nitrogen Having a component concentration distribution structure in which the amount changes continuously,
Further, Zr / (Zr + Ti) indicating the mutual content ratio of Zr and Ti, and oxygen / carbon and nitrogen at the highest content points of Zr and oxygen, oxygen / (oxygen + carbon + nitrogen), carbon / (oxygen + carbon + Nitrogen), and nitrogen / (oxygen + carbon + nitrogen) in atomic ratio,
Zr / (Zr + Ti): 0.80 to 0.98,
Oxygen / (oxygen + carbon + nitrogen): 0.80 to 0.98,
Carbon / (oxygen + carbon + nitrogen): 0.01 to 0.10,
Nitrogen / (oxygen + carbon + nitrogen): 0.01 to 0.10,
Ti / (Ti + Zr) indicating the mutual content ratio of Ti and Zr, and carbon / nitrogen / oxygen at the highest content points of Ti, carbon and nitrogen, and carbon / (carbon + nitrogen + oxygen) and nitrogen / (carbon + Nitrogen + oxygen) and oxygen / (carbon + nitrogen + oxygen)
Ti / (Ti + Zr): 0.80 to 0.98,
Carbon / (carbon + nitrogen + oxygen): 0.40 to 0.49,
Nitrogen / (carbon + nitrogen + oxygen): 0.40 to 0.49,
Oxygen / (carbon + nitrogen + oxygen): 0.02 to 0.20,
And the interval between the adjacent highest content points of Zr and oxygen and the highest content points of Ti, carbon, and nitrogen is 0.01 to 0.2 μm;
Surface coated cemented carbide cutting tool with a hard coating layer that exhibits excellent chipping resistance under high-speed heavy cutting conditions.
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| JP2008087150A (en) * | 2006-09-05 | 2008-04-17 | Tungaloy Corp | Coated cutting tool and its manufacturing method |
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| JP2008087150A (en) * | 2006-09-05 | 2008-04-17 | Tungaloy Corp | Coated cutting tool and its manufacturing method |
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