JP3900523B2 - Surface coated cemented carbide cutting tool with excellent chipping resistance with hard coating layer under high speed heavy cutting conditions - Google Patents
Surface coated cemented carbide cutting tool with excellent chipping resistance with hard coating layer under high speed heavy cutting conditions Download PDFInfo
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Description
【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】
【0020】
【表2】
【0021】
【表3】
【0022】
【表4】
【0023】
【表5】
【0024】
【表6】
【0025】
【表7】
【0026】
【表8】
【0027】
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]
BACKGROUND OF THE INVENTION
In the present invention, the hard coating layer has high strength and is excellent in high-temperature hardness and heat resistance. Therefore, high-speed cutting such as various types of steel and cast iron is particularly suitable for high cutting and high cutting with high thermal mechanical impact. Even when performed under heavy cutting conditions such as feeding, the hard coating layer exhibits excellent chipping resistance and a surface-coated cemented carbide cutting tool that exhibits excellent wear resistance over a long period of time (hereinafter referred to as coated Hard 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. Also, the throwaway tip is detachably attached and cutting is performed in the same way as the solid type end mill Throwaway end mill tools are known.
[0003]
Further, as a coated carbide tool, a substrate made of tungsten carbide (hereinafter referred to as WC) -based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) -based cermet (hereinafter collectively referred to as a cemented carbide substrate). ) Are alternately laminated with Zr oxide (hereinafter referred to as ZrO 2 ) layers and Ti carbonitride (hereinafter referred to as TiCN) layers having an individual layer thickness of 1 μm or less, and 2 to 20 μm in total. A coated cemented carbide tool formed by vapor deposition with an average layer thickness has been proposed, and the ZrO 2 —TiCN alternating lamination constituting the hard coating layer has high-temperature hardness and heat resistance due to the ZrO 2 layer and strength due to the TiCN layer. For this reason, it is also known that such coated carbide tools exhibit excellent cutting performance when used for continuous cutting and intermittent cutting of various steels and cast irons (see, for example, Patent Document 1).
[0004]
Furthermore, as shown in the schematic longitudinal sectional view of FIG. 1, for example, the coated carbide tool has a stainless steel reaction gas blowing pipe standing at the center thereof. A graphite cemented carbide substrate support pallet illustrated in a schematic perspective view in (a) and a schematic plan view in (b) is skewered and laminated, and these are heated by a heater through a stainless steel cover. A chemical vapor deposition apparatus having a structure is used, and the cemented carbide substrate is mounted on the chemical vapor deposition apparatus in a state where the carbide substrate is placed as illustrated in a number of reaction gas passage hole positions formed on the bottom surface of the carbide substrate support pallet. Then, after heating the inside of the apparatus to a predetermined temperature within a range of 800 to 1100 ° C. with a heater, for forming the ZrO 2 layer, the reaction gas is in volume% (hereinafter,% of the reaction gas is volume%). ),
ZrCl 4 : 1-3%
CO 2: 7.5~11.5%,
HCl: 7.2-11.2%
H 2 : Remaining
For forming a TiCN layer, a reactive gas having a composition consisting of:
TiCl 4: 1~3%,
CH 4: 11~15%,
N 2 : 40-60%
H 2 : Remaining
The reaction gas pressure in the apparatus is maintained at a predetermined pressure within a range of 7 to 40 kPa through the reaction gas blowing pipe into the apparatus that has been evacuated in advance. However, it is also known that it is produced by forming a hard coating layer composed of ZrO 2 —TiCN alternating layers by alternately introducing them (see, for example, Patent Document 1).
[0005]
[Patent Document 1]
JP-A-55-145165 [0006]
[Problems to be solved by the invention]
In recent years, there has been a remarkable increase in the performance of cutting equipment, while there has been a strong demand for labor saving and energy saving and further cost reduction for cutting work. Although there is a tendency to be forced to perform cutting under heavy cutting conditions such as high feed, the above-mentioned conventional coated carbide tools are used for heavy cutting such as high cutting and high feed with high thermal mechanical impact. When used for high speeds, the ZrO 2 layer of the hard coating layer composed of ZrO 2 —TiCN alternating layers has excellent high temperature hardness and heat resistance, but has insufficient strength. Since it becomes the starting point of fracture, it causes chipping (microcracking). Also, the TiCN layer has high strength but low high temperature hardness and low heat resistance. Now wear progress in heavy cutting is 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 carbide tool that exhibits excellent chipping resistance with a hard coating layer particularly in high-speed heavy cutting and exhibits excellent wear resistance over a long period of time. As a result of 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, ie, a composite carbon of Zr and Ti, which is a constituent component of the hard coating layer of the conventional coated carbide tool. When forming a nitride 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. In the hard coating layer composed of the Zr-Ti carbonitride oxide layer, the highest content point of Zr and oxygen and the highest content point of Ti, carbon, and nitrogen are alternately arranged at predetermined intervals along the thickness direction. For the purpose of repeatedly forming the above, the highest content point of Zr and oxygen, the reaction gas composition corresponding to the highest content point of Ti, carbon, and nitrogen, and Zr and oxygen, Ti, carbon, and nitrogen between the two points. Reaction gas composition corresponding to the continuous variation, the further the distance between two points, and inputs based on historical data, according to a control signal from the reaction gas composition and flow rates central controller, H 2 from the raw material gas cylinder While controlling the flow rate of gas, CO 2 gas, CH 4 gas, N 2 gas, CH 3 CN gas, and HCl gas, and further the flow rate of ZrCl 4 gas and TiCl 4 gas with the respective raw material gas flow rate automatic control devices, When introduced into the reaction gas blowing tube of a chemical vapor deposition apparatus, the highest content point of Zr and oxygen and the highest content point of Ti, carbon, and nitrogen exist alternately at predetermined intervals along the layer thickness direction. And from the highest content point of Zr and oxygen, the highest content point of Ti, carbon, and nitrogen, and from the highest content point of Ti, carbon, and nitrogen, And a hard coating layer composed of a Zr—Ti carbonitride oxide layer having a component concentration distribution structure in which the contents of Zr and oxygen, and Ti, carbon and nitrogen continuously change to the highest content point of oxygen and oxygen. To be like that.
[0008]
(B) In the Zr-Ti carbonitride oxide layer having the repeated continuous change component concentration distribution structure of (a) above,
Zr / Ti at the highest content point of Zr and oxygen, and Zr / (Zr + Ti) indicating the mutual content ratio of oxygen, carbon, and nitrogen, and oxygen / (oxygen + carbon + nitrogen), carbon / (oxygen + carbon + nitrogen) ), And nitrogen / (oxygen + carbon + nitrogen), respectively, in atomic ratios,
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): 0.01-0.10,
Ti / Zr at the highest content point of Ti, carbon, and nitrogen, and Ti / (Ti + Zr) indicating the mutual content ratio of carbon, nitrogen, and oxygen, and carbon / (carbon + nitrogen + oxygen), nitrogen / (carbon + Nitrogen + oxygen) and oxygen / (carbon + nitrogen + oxygen) in atomic ratios, respectively
Ti / (Ti + Zr): 0.80 to 0.98,
Carbon / (carbon + nitrogen + oxygen): 0.40-0.49,
Nitrogen / (carbon + nitrogen + oxygen): 0.40-0.49,
Oxygen / (carbon + nitrogen + oxygen): 0.02 to 0.20,
And the distance in the thickness direction between the highest content point of Zr and oxygen adjacent to each other and the highest content point of Ti, carbon, and nitrogen is 0.01 to 0.2 μm.
The highest content point of Zr and oxygen shows excellent high temperature hardness and heat resistance corresponding to the high temperature hardness and heat resistance of ZrO 2 , while the highest content point of Ti, carbon, and nitrogen shows that of TiCN. High strength corresponding to the strength of the material is ensured, and the distance between the highest content point of Zr and oxygen and the highest content point of Ti, carbon, and nitrogen is extremely small. Hardness, heat resistance, and high strength are achieved, and further, the content of Zr, oxygen, Ti, carbon, and nitrogen continuously changes (component concentration distribution structure) between the two points. Therefore, a coated carbide tool composed of a Zr-Ti carbonitride oxide layer with a hard coating layer is particularly suitable for cutting various steels and cast irons. In addition, the hard coating layer has excellent chipping resistance and excellent wear resistance over a long period of time even under heavy cutting conditions such as high cutting with high thermal mechanical impact and high feed. To come out.
The research results shown in (a) and (b) above were obtained.
[0009]
The present invention has been made based on the above research results, and a hard coating layer composed of a Zr-Ti carbonitride oxide layer is deposited on the surface of a cemented carbide substrate with an overall average layer thickness of 2 to 20 μm. In the coated carbide tool
In the hard coating layer, the highest content point of Zr and oxygen and the highest content point of Ti, carbon, and nitrogen exist alternately at predetermined intervals along the 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, and from the highest content point of Ti, carbon, and nitrogen, to the highest content point of Zr and oxygen, Zr and oxygen, and Ti, carbon, and nitrogen It has a component concentration distribution structure whose amount changes continuously,
Further, Zr and Ti at the highest content point of Zr and oxygen, and Zr / (Zr + Ti) indicating the mutual content ratio of oxygen, carbon, and nitrogen, and oxygen / (oxygen + carbon + nitrogen), carbon / (oxygen + carbon). + Nitrogen) and nitrogen / (oxygen + carbon + nitrogen), respectively, in atomic ratios
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): 0.01-0.10,
Ti / Zr at the highest content point of Ti, carbon, and nitrogen, and Ti / (Ti + Zr) indicating the mutual content ratio of carbon, nitrogen, and oxygen, and carbon / (carbon + nitrogen + oxygen), nitrogen / (carbon + Nitrogen + oxygen) and oxygen / (carbon + nitrogen + oxygen) in atomic ratios, respectively
Ti / (Ti + Zr): 0.80 to 0.98,
Carbon / (carbon + nitrogen + oxygen): 0.40-0.49,
Nitrogen / (carbon + nitrogen + oxygen): 0.40-0.49,
Oxygen / (carbon + nitrogen + oxygen): 0.02 to 0.20,
And the distance between the highest content point of Zr and oxygen adjacent to each other and the highest content point of Ti, carbon, and nitrogen is 0.01 to 0.2 μm.
This is characterized by a coated carbide tool that exhibits excellent chipping resistance under high-speed heavy cutting conditions.
[0010]
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) Maximum content point of Zr and oxygen Zr-Ti nitrous oxide The Ti, carbon, and nitrogen components of the oxynitride layer improve the strength, and the Zr and oxygen components improve the high-temperature hardness and heat resistance. Therefore, at the highest content point of Zr and oxygen, the content ratio of Zr and oxygen is relatively increased to improve high-temperature hardness and heat resistance, so that 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 indicating the mutual content ratio of Zr and Ti, and oxygen, carbon and nitrogen are all in atomic ratios (hereinafter the same). When 98 is exceeded, Ti / (Ti + Zr) value: less than 0.02, and carbon / (oxygen + carbon + nitrogen) value and 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 exist adjacent to each other, a decrease in the strength of the layer itself is inevitable, resulting in chipping and the like. When the same value is less than 0.80, Ti / (Ti + Zr) value exceeds 0.20, and carbon / (oxygen + carbon + nitrogen) value and nitrogen / (oxygen + carbon + nitrogen) Both values increase beyond 0.10, while the proportions of Zr and oxygen are relatively reduced. As a result, the high temperature hardness and heat resistance are drastically reduced, which causes wear acceleration. / (Zr + Ti) and oxygen / (oxygen + carbon + nitrogen) values of 0.80 to 0.98, carbon / (oxygen + carbon + nitrogen) and nitrogen / (oxygen + carbon + nitrogen) values In all cases, it was determined to be 0.01 to 0.10.
[0011]
(B) Maximum content point of Ti, carbon, and nitrogen As described above, the maximum content point of Zr and oxygen has relatively high temperature hardness and heat resistance, but on the other hand, the strength is relatively insufficient. In order to compensate for the insufficient strength of the highest content point 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 Ti / (Ti + Zr) value indicating the mutual content ratio of Ti and Zr, and carbon, nitrogen and oxygen exceeds 0.98, and the carbon / (oxygen + carbon + nitrogen) value and nitrogen / (oxygen + carbon + When both nitrogen) values exceed 0.49, the Zr value is less than 0.02 and the oxygen / (carbon + nitrogen + oxygen) value is less than 0.02, which is substantially Ti carbonitride. Therefore, the predetermined high-temperature hardness and heat resistance cannot be secured at the highest content point of Ti, carbon, and nitrogen, which causes wear promotion, while Ti / (Ti + Zr) When the value is less than 0.80, the carbon / (carbon + nitrogen + oxygen) value and the nitrogen / (carbon + nitrogen + oxygen) value are both less than 0.40, the Zr / (Zr + Ti) value exceeds 0.20. And the oxygen / (carbon + nitrogen + oxygen) value is 0. Since the ratio of Ti, carbon, and nitrogen is relatively low and the desired strength cannot be ensured and chipping is likely to occur as a result, Ti / (Ti + Zr) Of 0.80 to 0.98, carbon / (carbon + nitrogen + oxygen) and nitrogen / (carbon + nitrogen + oxygen) values of 0.40 to 0.49, oxygen / (carbon + nitrogen +) The value of (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 distance is less than 0.01 μm, it is difficult to clearly form each point with the above composition. As a result, the desired high-temperature hardness and heat resistance, and high strength cannot be ensured in the layer, and when the distance exceeds 0.2 μm, the disadvantages of the respective points, that is, the highest of Zr and oxygen Insufficient strength if included, high temperature hardness and insufficient heat resistance appear locally in the layer if the highest content point of Ti, carbon, and nitrogen. Therefore, the interval was set to 0.01 to 0.2 μm.
[0013]
(D) Overall average layer thickness of hard coating layer If the layer thickness is less than 2 μm, desired wear resistance cannot be ensured. On the other hand, if the average layer thickness exceeds 20 μm, chipping tends to occur. Therefore, the average layer thickness was determined to be 2 to 20 μm.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Next, the coated 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, 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 the holding conditions, and after sintering, the cutting edge portion was subjected to a honing process of R: 0.03, and the carbide bases A1 to A10 made of WC-based cemented carbide having a chip shape of ISO standard CNMG160608 Formed.
[0015]
In addition, as raw material powders, all are TiCN (weight ratio TiC / TiN = 50/50) powder, Mo 2 C powder, ZrC powder, NbC powder, TaC powder, WC powder having an average particle diameter of 0.5 to 2 μm. Co powder and Ni powder are prepared, and these raw material powders are blended in the blending composition shown in Table 2, wet mixed by a ball mill for 24 hours, dried, and then pressed into a compact at a pressure of 100 MPa. The green compact was sintered in a 2 kPa nitrogen atmosphere 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, and ISO standard / CNMG160612. TiCN-based cermet carbide substrates B1 to B6 having the following chip shape were formed.
[0016]
Next, each of the above-mentioned carbide substrates A1 to A10 and B1 to B6 is ultrasonically cleaned in acetone and dried, and then the carbide shown in FIG. 2 is placed in the chemical vapor deposition apparatus shown in FIG. First, when the inside of the apparatus was heated to 900 ° C. with a heater, it was loaded with TiCl 4 : 4.2%, N 2 : 30%, H 2 : remaining. A reactive gas having a composition is introduced through a reactive gas blowing tube, the reaction atmosphere pressure in the apparatus is set to 30 kPa, and this state is maintained for 30 minutes, and the titanium nitride having an average layer thickness of 0.3 μm as a base adhesion layer ( TiN) layer is formed, and the atmospheric temperature in the apparatus is then heated to 1020 ° C. with a heater, and then the reaction gas composition and flow rate central control apparatus 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 point of Zr and oxygen shown in Tables 3 and 4, and target oxygen / (oxygen + carbon + nitrogen), target carbon / (oxygen + carbon + nitrogen) ), And target nitrogen / (oxygen + carbon + nitrogen), and target Ti / (Ti + Zr) at the highest content point of Ti, carbon, and nitrogen, and target carbon / (carbon + nitrogen + oxygen), target nitrogen / (carbon + Nitrogen + oxygen), and reaction gas composition corresponding to target oxygen / (carbon + nitrogen + oxygen), the highest content point of Zr and oxygen, and Zr and oxygen between the highest content points of Ti, carbon, and nitrogen, And the reaction gas composition corresponding to the continuous change in the contents of Ti, carbon and nitrogen, and the target distance between the two points shown in Tables 5 and 6 and the target total layer thickness of the hard coating layer are input. Composition and Through the raw material gas flow automatic control of the control valve built which operate in accordance with a signal from the flow central controller, H 2 gas as a source gas, CH 4 gas, N 2 gas, CH 3 CN gas, CO 2 gas, and HCl Gas, further ZrCl 4 gas and TiCl 4 gas (in this case, ZrCl 4 gas is formed by reacting metal Zr with flow-controlled HCl gas in a ZrCl 4 gas generator, and TiCl 4 gas is sends as flow-controlled H 2 gas as a carrier gas to the TiCl 4 gas generator is sent where the raw material gas flow automatic control device with vaporized TiCl 4 gas from a liquid, further CH 3 CN gas, CH 3 CH vaporizer heated to gasify liquid CH 3 CN is sent to the raw material gas flow automatic control device) While controlling the flow rate, it was introduced into the apparatus from the reaction gas blowing tube of the chemical vapor deposition apparatus of FIG. 1 (the reaction atmosphere pressure in the apparatus is always maintained at 7 kPa), and thus the layer thickness was formed on the surface of the carbide substrate. Target Zr / (Zr + Ti) shown in Tables 5 and 6 along the direction, and target oxygen / (oxygen + carbon + nitrogen), target carbon / (oxygen + carbon + nitrogen), and target nitrogen / (oxygen + carbon + Nitrogen) Zr and oxygen maximum content points and target Ti / (Ti + Zr), target carbon / (carbon + nitrogen + oxygen), target nitrogen / (carbon + nitrogen + oxygen), and target oxygen / (carbon + nitrogen +) The maximum content points of Ti, carbon, and nitrogen of oxygen) are alternately repeated at the target intervals shown in Tables 5 and 6, and from the maximum content points of Zr and oxygen, the maximum content points of Ti, carbon, and nitrogen Highest content point, Ti, A component concentration distribution structure in which the contents of Zr and oxygen, and Ti, carbon and nitrogen continuously change from the highest content point of element and nitrogen to the highest content point of Zr and oxygen, respectively, and Table 5 , 6 to deposit a hard coating layer having a target total layer thickness, the present invention is a surface coated cemented carbide throwaway tip (hereinafter referred to as the present coated carbide tip) as a coated carbide tool of the present invention. 1 to 16 were produced.
[0017]
For comparison purposes, these carbide substrates A1 to A10 and B1 to B6 were ultrasonically cleaned in acetone and dried, and then charged into the normal chemical vapor deposition apparatus shown in FIGS. , ZrO 2 layer formation conditions,
Reaction gas composition: ZrCl 4 : 1.3%, CO 2 : 10.5%, HCl: 10.2%, H 2 : remaining,
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 : remaining,
Reaction atmosphere temperature: 1020 ° C.
Reaction atmosphere pressure: 7 kPa,
As shown in Table 7, 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 is applied to the surfaces of the superhard substrates A1 to A10 and B1 to B6, respectively. , 8 were manufactured as conventional coated carbide tools, and the conventional surface coated cemented carbide throwaway tips (hereinafter referred to as conventional coated carbide tips) 1 to 16 were produced respectively. .
[0018]
Next, with the present invention coated carbide tips 1-16 and conventional coated carbide tips 1-16, in a state where this is screwed to the tip of the tool steel tool with a fixing jig,
Work material: JIS / SCr415 round bar,
Cutting speed: 450 m / min. ,
Cutting depth: 5.0mm,
Feed: 0.3 mm / rev. ,
Cutting time: 5 minutes
Dry-type continuous high-speed high-cut cutting test of alloy steel under the conditions of
Work material: JIS / S15C lengthwise equal length 4 vertical grooved round bars,
Cutting speed: 500 m / min. ,
Cutting depth: 2.0 mm
Feed: 0.6 mm / rev. ,
Cutting time: 5 minutes
Dry intermittent high-speed high-feed cutting test of carbon steel under the conditions of
Work material: JIS · FC250 lengthwise equal length 4 round bar with round groove,
Cutting speed: 500 m / min. ,
Cutting depth: 6.0 mm,
Feed: 0.2 mm / rev. ,
Cutting time: 5 minutes
A dry interrupted 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 Tables 5-8.
[0019]
[Table 1]
[0020]
[Table 2]
[0021]
[Table 3]
[0022]
[Table 4]
[0023]
[Table 5]
[0024]
[Table 6]
[0025]
[Table 7]
[0026]
[Table 8]
[0027]
About the hard coating layer which comprises this invention coated carbide | carbonized_material chip | tips 1-16 obtained as a result, and conventional coated carbide | carbonized_material chip | tips 1-16, content of Zr, Ti, oxygen, carbon, and nitrogen along a thickness direction Was measured using an Auger spectroscopic analyzer, and from the measurement results, the values of Zr / (Zr + Ti) and Ti / (Ti + Zr) at each measurement point, oxygen / (oxygen + carbon + nitrogen), carbon / (oxygen + carbon) were measured. + Nitrogen), and nitrogen / (oxygen + carbon + nitrogen) values were calculated. In the hard coating layers of the present coated carbide chips 1 to 16, the highest content point of Zr and oxygen, Ti, carbon, and The highest content point of nitrogen alternately and repeatedly exists at substantially the same composition and interval as the target value, and the highest content point of Ti, carbon, and nitrogen from the highest content point of Zr and oxygen, said Ti, carbon It is confirmed that it has a component concentration distribution structure in which the contents of Zr and Ti, and oxygen, carbon and nitrogen continuously change from the highest content point of nitrogen and nitrogen to the highest content point of oxygen and oxygen. The layer thickness also showed substantially the same value as the target overall layer thickness. Also, in the hard coating layers of the conventional coated carbide chips 1 to 16, ZrO 2 layers and TiCN layers having an average layer thickness substantially the same as the target layer thickness are alternately alternated and the average is substantially the same as the target overall layer thickness. It was confirmed that the film was formed with a layer thickness.
[0028]
【The invention's effect】
From the results shown in Tables 5 to 8, the hard coating layer has, in the layer thickness direction, the highest content point of Zr and oxygen having relatively high temperature hardness and heat resistance, and Ti and carbon having relatively high strength. And the highest content point of nitrogen alternately and at predetermined intervals, and from the highest content point of Zr and oxygen, the highest content point of Ti, carbon, and nitrogen, Ti, carbon, and nitrogen The coated carbide chips 1 to 16 of the present invention having a component concentration distribution structure in which the contents of Zr and oxygen, and Ti, carbon and nitrogen continuously change from the highest content point to the highest content point of Zr and oxygen are: Even when cutting various steels and cast irons at high speeds and under heavy cutting conditions such as high cutting and high feed with high thermal mechanical impact, the hard coating layer has excellent chipping resistance. Show and excel 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 these conditions, it becomes the starting point of occurrence of chipping, and since the progress of wear of the TiCN layer is promoted by high heat generation during cutting, it is clear that the service life is reached in a relatively short time.
As described above, the coated cemented carbide tool of the present invention is capable of cutting various types of steel and cast iron as well as cutting under normal conditions at high speed and with high thermal mechanical impact. Even 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 can cope with the cost reduction sufficiently satisfactorily.
[Brief description of the drawings]
FIG. 1 is a schematic longitudinal sectional view illustrating a chemical vapor deposition apparatus used for forming a hard coating layer constituting a coated carbide tool.
2A and 2B show a cemented carbide substrate support pallet that is a structural member of a chemical vapor deposition apparatus, in which 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)
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-coated ultra-hard surface 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 base cemented carbide substrate or a titanium carbonitride-based cermet substrate with an overall average layer thickness of 2 to 20 μm In a hard alloy cutting tool, the hard coating layer is repeatedly present along the thickness direction with the highest content point of Zr and oxygen and the highest content point of Ti, carbon, and nitrogen at predetermined intervals. Zr and oxygen from the highest content point of Zr and oxygen 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 Zr and oxygen, and It has a component concentration distribution structure in which the contents of Ti, carbon and nitrogen continuously change,
Further, Zr and Ti at the highest content point of Zr and oxygen, and Zr / (Zr + Ti) indicating the mutual content ratio of oxygen, carbon, and nitrogen, and oxygen / (oxygen + carbon + nitrogen), carbon / (oxygen + carbon). + Nitrogen) and nitrogen / (oxygen + carbon + nitrogen), respectively, in atomic ratios
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): 0.01-0.10,
Ti / Zr at the highest content point of Ti, carbon, and nitrogen, and Ti / (Ti + Zr) indicating the mutual content ratio of carbon, nitrogen, and oxygen, and carbon / (carbon + nitrogen + oxygen), nitrogen / (carbon + Nitrogen + oxygen) and oxygen / (carbon + nitrogen + oxygen) in atomic ratios, respectively
Ti / (Ti + Zr): 0.80 to 0.98,
Carbon / (carbon + nitrogen + oxygen): 0.40-0.49,
Nitrogen / (carbon + nitrogen + oxygen): 0.40-0.49,
Oxygen / (carbon + nitrogen + oxygen): 0.02 to 0.20,
And the interval between the highest content point of Zr and oxygen adjacent to each other and the highest content point of Ti, carbon, and nitrogen is 0.01 to 0.2 μm,
A surface-coated cemented carbide cutting tool that exhibits excellent chipping resistance under high-speed heavy cutting conditions.
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