JP2004322279A - Surface-coated cemented carbide cutting tool having hard coating layer exhibiting superior chipping resistance under high speed double cutting condition - Google Patents

Surface-coated cemented carbide cutting tool having hard coating layer exhibiting superior chipping resistance under high speed double cutting condition Download PDF

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JP2004322279A
JP2004322279A JP2003123256A JP2003123256A JP2004322279A JP 2004322279 A JP2004322279 A JP 2004322279A JP 2003123256 A JP2003123256 A JP 2003123256A JP 2003123256 A JP2003123256 A JP 2003123256A JP 2004322279 A JP2004322279 A JP 2004322279A
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hard coating
coating layer
content
content point
cemented carbide
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JP4366987B2 (en
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Koichi Maeda
浩一 前田
Yusuke Tanaka
裕介 田中
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Mitsubishi Materials Corp
Mitsubishi Materials Kobe Tools Corp
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Mitsubishi Materials Corp
Mitsubishi Materials Kobe Tools Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-coated cemented carbide cutting tool having a hard coating layer exhibiting superior chipping resistance under a high speed double cutting condition. <P>SOLUTION: This surface-coated cemented carbide cutting tool is formed by physically depositing the hard coating layer composed of a composite nitride layer of Ti, Si, and Zr in the average layer thickness of 0.5 to 15 μm on a surface of a tungsten carbide group cemented carbide base body or a titanium carbonitride type cermet base body; and is constituted so that the hard coating layer has a component concentration distribution structure that an Si maximum inclusion point and an Si minimum inclusion point alternately and repeatedly exist at a prescribed interval in the layer thickness direction, and an Si inclusion rate continuously changes between both points; and is composed of the hard coating layer that the Si maximum inclusion point satisfies the composition formula : (Ti<SB>1-(X + Z)</SB>Si<SB>X</SB>Zr<SB>Z</SB>)N (here, X indicates 0.45 to 0.60, and Z indicates 0.05 to 0.15 in the atomic ratio); the Si minimum inclusion point satisfies the composition formula : (Ti<SB>1-(Y+Z)</SB>Si<SB>Y</SB>Zr<SB>Z</SB>)N (here, Y indicates 0.03 to 0.25, and Z indicates 0.05 to 0.15 in the atomic ratio); and an interval between the adjacent Si maximum inclusion point and the Si minimum inclusion point is 0.01 to 0.1 μm. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【0001】
【発明の属する技術分野】
この発明は、硬質被覆層が一段とすぐれた高温強度を有し、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い発熱を伴なう高速切削加工を、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(以下、被覆超硬工具という)に関するものである。
【0002】
【従来の技術】
一般に、被覆超硬工具には、各種の鋼や鋳鉄などの被削材の旋削加工や平削り加工にバイトの先端部に着脱自在に取り付けて用いられるスローアウエイチップ、穴あけ切削加工などに用いられるドリルやミニチュアドリル、さらに面削加工や溝加工、肩加工などに用いられるソリッドタイプのエンドミルなどがあり、また前記スローアウエイチップを着脱自在に取り付けて前記ソリッドタイプのエンドミルと同様に切削加工を行うスローアウエイエンドミル工具などが知られている。
【0003】
また、被覆超硬工具として、炭化タングステン(以下、WCで示す)基超硬合金または炭窒化チタン(以下、TiCNで示す)基サーメットからなる基体(以下、これらを総称して超硬基体と云う)の表面に、
組成式:(Ti1−XSi)N(ただし、原子比で、Xは0.45〜0.60を示す)、
を満足するTiとSiの複合窒化物[以下、(Ti,Si)Nで示す]層からなる硬質被覆層を0.5〜15μm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,Si)N層がSiによるすぐれた高温硬さおよび耐熱性、さらにTiによるすぐれた高温強度を有することから、各種の鋼や鋳鉄などの連続切削や断続切削加工に用いられ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2に概略説明図で示される物理蒸着装置の1種であるアークイオンプレーティング装置に上記の超硬基体を装入し、ヒータで装置内を、例えば400℃の温度に加熱した状態で、アノード電極と所定組成を有するTi−Si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,Si)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】
【特許文献1】
特開平8−118106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、切削速度は高速化し、かつ高切り込みや高送りなどの重切削条件での切削加工が強く求められる傾向にあるが、上記の従来被覆超硬工具においては、これを通常の切削加工条件で用いた場合には問題はないが、高い発熱を伴なう高速切削加工を機械的衝撃の高い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強度不足が原因でチッピング(微小割れ)が発生し易く、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,Si)N層は、厚さ全体に亘って実質的に均一な組成を有し、したがって均質な性質を有するが、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、一方側に上記の従来(Ti,Si)N層の形成にカソード電極(蒸発源)として用いられたTi−Si合金に、さらにZr成分を合金成分として含有させてなるTi−Si−Zr合金を配置し、他方側には前記Ti−Si−Zr合金に比して相対的にSi含有割合の低いTi−Si−Zr合金をいずれもカソード電極(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に、中心軸から半径方向に所定距離離れた位置に外周部に沿って複数の超硬基体をリング状に装着し、この状態で装置内雰囲気を窒素雰囲気として前記回転テーブルを回転させると共に、蒸着形成される硬質被覆層の層厚均一化を図る目的で超硬基体自体も自転させながら、前記の両側のカソード電極(蒸発源)とアノード電極との間にアーク放電を発生させて、前記超硬基体の表面に(Ti,Si,Zr)N層を形成すると、この結果の(Ti,Si,Zr)N層においては、回転テーブル上にリング状に配置された前記超硬基体が上記の一方側のTi−Si−Zr合金のカソード電極(蒸発源)に最も接近した時点で層中にSi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Si含有割合の低いTi−Si−Zr合金のカソード電極に最も接近した時点で層中にSi最低含有点が形成され、上記回転テーブルの回転によって層中には厚さ方向にそって前記Si最高含有点とSi最低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Si最高含有点から前記Si最低含有点、前記Si最低含有点から前記Si最高含有点へSi含有割合が連続的に変化する成分濃度分布構造をもつようになること。
【0008】
(b)上記(a)の繰り返し連続変化成分濃度分布構造の(Ti,Si,Zr)N層において、対向配置の一方側のカソード電極(蒸発源)であるTi−Si−Zr合金におけるSi含有割合を上記の従来(Ti,Si)N層形成用Ti−Si合金のSi含有割合に相当するものとし、同他方側のカソード電極(蒸発源)であるTi−Si−Zr合金におけるSi含有割合を上記の従来Ti−Si合金のSi含有割合に比して相対的に低いものとすると共に、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Si最高含有点が、組成式:(Ti1−(X+ SiZr)N(ただし、原子比で、Xは0.45〜0.60、Z:0.05〜0.15を示す)、
上記Si最低含有点が、組成式:(Ti1−( Si Zr)N(ただし、原子比で、Yは0.03〜0.25、Y:0.05〜0.15を示す)、
を満足し、かつ隣り合う上記Si最高含有点とSi最低含有点の厚さ方向の間隔を0.01〜0.1μmとすると、
上記Si最高含有点部分では、上記の従来(Ti,Si)N層の具備する高温硬さおよび耐熱性に相当するすぐれた高温硬さおよび耐熱性を有し、かつTiおよびZr成分による高温強度も具備し、一方上記Si最低含有点部分では、前記Si最高含有点部分に比してSi含有割合が低く、相対的にTi含有割合の高いものとなるので、Zr成分に用高温強度向上効果と相俟って、一段と高い高温強度が確保されるようになり、かつこれらSi最高含有点とSi最低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、さらに一段とすぐれた高温強度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(Ti,Si,Zr)N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、高い発熱を伴なう速い切削速度で、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、硬質被覆層がすぐれた耐チッピング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、(Ti,Si,Zr)N層からなる硬質被覆層を0.5〜15μmの平均層厚で物理蒸着してなる被覆超硬工具にして、上記硬質被覆層を、層厚方向にそって、Si最高含有点とSi最低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Si最高含有点から前記Si最低含有点、前記Si最低含有点から前記Si最高含有点へSi含有割合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Si最高含有点が、
組成式:(Ti1−(X+ SiZr)N(ただし、原子比で、Xは0.45〜0.60、Z:0.05〜0.15を示す)、
上記Si最低含有点が、
組成式:(Ti1−( Si Zr)N(ただし、原子比で、Yは0.03〜0.25、Z:0.05〜0.15を示す)、
を満足し、かつ隣り合う上記Si最高含有点とSi最低含有点の間隔が、0.01〜0.1μmである、
硬質被覆層で構成してなる、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)Si最高含有点の組成
Si最高含有点の(Ti,Si,Zr)Nにおいて、Ti成分は高温強度を向上させ、同Siは高温硬さと耐熱性、さらにZr成分はTiとの共存において高温強度を一段と向上させる作用があり、したがってSi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たものになり、高熱発生を伴う高速切削に適応したものになるが、Siの含有割合を示すX値がTiとZrの合量に占める割合(原子比)で0.60を越えると、相対的にTi成分の含有割合が少なくなり過ぎて、すぐれた高温強度を有するSi最低含有点が隣接して存在しても層自体の高温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X値が同0.45未満になると、所定のすぐれた高温硬さと耐熱性を確保することが困難になり、摩耗が急速に進行するようになることから、X値を0.45〜0.60と定めた。
さらに、Zr成分には上記の通り高温強度を向上させる作用があるが、Zrの含有割合を示すZ値がSiとTiの合量に占める割合(原子比)で0.05未満では所望の高温強度向上効果が得られず、さらに同Z値が0.15を超えると、高温硬さおよび耐熱性に低下傾向が現れるようになることから、Z値を0.05〜0.15と定めた。
【0011】
(b)Si最低含有点の組成
上記の通りSi最高含有点はSi成分の高含有によりすぐれた高温硬さと耐熱性を有するが、反面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の高速切削加工では高温強度不足は避けられず、このSi最高含有点の高温強度不足を補う目的で、Ti含有割合が相対的に高く、一方Si含有割合が低く、これによって一段とすぐれた高温強度を有するようになるSi最低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Siの割合を示すY値がTiおよびZr成分との合量に占める割合(原子比)で0.25を越えると、所望のすぐれた高温強度を確保することができず、一方同Y値が0.03未満になると、所定の高温硬さおよび耐熱性の確保が困難になり、これが原因で高温硬さおよび耐熱性のすぐれたSi最高含有点が隣接して存在しても層自体の摩耗進行が促進するようになることから、Si最低含有点でのSiの含有割合を示すY値を0.03〜0.25と定めた。
さらに、Si最低含有点におけるZr成分も、上記の通り高温強度を向上させ、もって高熱発生を伴う高速切削に適応させる目的で含有するものであり、したがってZ値が0.05未満では所望の高温強度向上効果が得られず、一方Z値が0.15を越えると高温硬さおよび耐熱性に低下傾向が現れるようになり、摩耗進行の原因となることから、Z値を0.05〜0.15と定めた。
【0012】
(c)Si最高含有点とSi最低含有点間の間隔
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Si最高含有点によるすぐれた高温硬さと耐熱性と、Si最低含有点による一段とすぐれた高温強度を確保することができなくなり、またその間隔が0.1μmを越えると重切削条件での高速切削加工でそれぞれの点がもつ欠点、すなわちSi最高含有点であれば高温強度不足、Si最低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0.01〜0.1μmと定めた。
【0013】
(d)硬質被覆層の平均層厚
その層厚が0.5μm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0.5〜15μm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。
(実施例1)
原料粉末として、いずれも1〜3μmの平均粒径を有するWC粉末、TiC粉末、VC粉末、TaC粉末、NbC粉末、Cr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48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:1420℃に1時間保持の条件で焼結し、焼結後、切刃部分にR:0.03のホーニング加工を施してISO規格・CNMG120412のチップ形状をもったWC基超硬合金製の超硬基体A−1〜A−10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、MoC粉末、ZrC粉末、NbC粉末、TaC粉末、WC粉末、Co粉末、およびNi粉末を用意し、これら原料粉末を、表2に示される配合組成に配合し、ボールミルで72時間湿式混合し、乾燥した後、100MPaの圧力で圧粉体にプレス成形し、この圧粉体を2kPaの窒素雰囲気中、温度:1520℃に1時間保持の条件で焼結し、焼結後、切刃部分にR:0.03のホーニング加工を施してISO規格・CNMG120412のチップ形状をもったTiCN系サーメット製の超硬基体B−1〜B−6を形成した。
【0016】
ついで、上記の超硬基体A−1〜A−10および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に、中心軸から半径方向に所定距離離れた位置に外周部に沿って複数の超硬基体をリング状に装着し、一方側のカソード電極(蒸発源)として、種々の成分組成をもったSi最高含有点形成用Ti−Si−Zr合金、他方側のカソード電極(蒸発源)としてSi最低含有点形成用Ti−Si−Zr合金を前記回転テーブルを挟んで対向配置し、またボンバード洗浄用金属Tiも装着し、まず、装置内を排気して0.5Pa以下の真空に保持しながら、ヒーターで装置内を500℃に加熱した後、前記回転テーブル上で自転しながら回転する超硬基体に−1000Vの直流バイアス電圧を印加し、かつカソード電極の前記金属Tiとアノード電極との間に100Aの電流を流してアーク放電を発生させ、もって超硬基体表面をTiボンバード洗浄し、ついで装置内に反応ガスとして窒素ガスを導入して3Paの反応雰囲気とすると共に、前記回転テーブル上で自転しながら回転する超硬基体に−30Vの直流バイアス電圧を印加し、かつそれぞれのカソード電極(前記Si最高含有点形成用Ti−Si−Zr合金およびSi最低含有点形成用Ti−Si−Zr合金)とアノード電極との間に150Aの電流を流してアーク放電を発生させ、もって前記超硬基体の表面に、厚さ方向に沿って表3,4に示される目標組成のSi最高含有点とSi最低含有点とが交互に同じく表3,4に示される目標間隔で繰り返し存在し、かつ前記Si最高含有点から前記Si最低含有点、前記Si最低含有点から前記Si最高含有点へSi含有割合が連続的に変化する成分濃度分布構造を有し、かつ同じく表3,4に示される目標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A−1〜A−10および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−Si合金を装着し、またボンバード洗浄用金属Tiも装着し、まず、装置内を排気して0.5Pa以下の真空に保持しながら、ヒーターで装置内を400℃に加熱した後、前記超硬基体に−1000Vの直流バイアス電圧を印加し、かつカソード電極の前記金属Tiとアノード電極との間に90Aの電流を流してアーク放電を発生させ、もって超硬基体表面をTiボンバード洗浄し、ついで装置内に反応ガスとして窒素ガスを導入して2Paの反応雰囲気とすると共に、前記超硬基体に印加するバイアス電圧を−200Vに下げて、前記カソード電極とアノード電極との間にアーク放電を発生させ、もって前記超硬基体A−1〜A−10およびB−1〜B−6のそれぞれの表面に、表5に示される目標組成および目標層厚を有し、かつ厚さ方向に沿って実質的に組成変化のない(Ti,Si)N層からなる硬質被覆層を蒸着することにより、従来被覆超硬工具としての従来表面被覆超硬合金製スローアウエイチップ(以下、従来被覆超硬チップと云う)1〜16をそれぞれ製造した。
【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・S45Cの丸棒、
切削速度:320m/min.、
切り込み:4.5mm、
送り:0.3mm/rev.、
切削時間:10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・FC300の長さ方向等間隔4本縦溝入り丸棒、
切削速度:300m/min.、
切り込み:2.5mm、
送り:0.6mm/rev.、
切削時間:5分、
の条件での鋳鉄の乾式断続高速高送り切削加工試験、さらに、
被削材:JIS・SNCM439の丸棒、
切削速度:350m/min.、
切り込み:5mm、
送り:0.2mm/rev.、
切削時間:10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6に示した。
【0019】
【表1】

Figure 2004322279
【0020】
【表2】
Figure 2004322279
【0021】
【表3】
Figure 2004322279
【0022】
【表4】
Figure 2004322279
【0023】
【表5】
Figure 2004322279
【0024】
【表6】
Figure 2004322279
【0025】
(実施例2)
原料粉末として、平均粒径:5.5μmを有する中粗粒WC粉末、同0.8μmの微粒WC粉末、同1.3μmのTaC粉末、同1.2μmのNbC粉末、同1.2μmのZrC粉末、同2.3μmのCr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7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50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を形成し、さらに前記の3種の丸棒焼結体から、研削加工にて、表7に示される組合せで、切刃部の直径×長さがそれぞれ6mm×13mm、10mm×22mm、および20mm×45mmの寸法、並びにいずれもねじれ角:30度の4枚刃スクエア形状をもった超硬基体(エンドミル)C−1〜C−8をそれぞれ製造した。
【0026】
ついで、これらの超硬基体(エンドミル)C−1〜C−8を、アセトン中で超音波洗浄し、乾燥した状態で、同じく図1に示されるアークイオンプレーティング装置に装入し、上記実施例1と同一の条件で、層厚方向に沿って表8に示される目標組成のSi最高含有点とSi最低含有点とが交互に同じく表8に示される目標間隔で繰り返し存在し、かつ前記Si最高含有点から前記Si最低含有点、前記Si最低含有点から前記Si最高含有点へSi含有割合が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8に示される目標層厚の硬質被覆層を蒸着することにより、本発明被覆超硬工具としての本発明表面被覆超硬合金製エンドミル(以下、本発明被覆超硬エンドミルと云う)1〜8をそれぞれ製造した。
【0027】
また、比較の目的で、上記の超硬基体(エンドミル)C−1〜C−8を、アセトン中で超音波洗浄し、乾燥した状態で、同じく図2に示される通常のアークイオンプレーティング装置に装入し、上記実施例1と同一の条件で、表9に示される目標組成および目標層厚を有し、かつ厚さ方向に沿って実質的に組成変化のない(Ti,Si)N層からなる硬質被覆層を蒸着することにより、従来被覆超硬工具としての従来表面被覆超硬合金製エンドミル(以下、従来被覆超硬エンドミルと云う)1〜8をそれぞれ製造した。
【0028】
つぎに、上記本発明被覆超硬エンドミル1〜8および従来被覆超硬エンドミル1〜8のうち、本発明被覆超硬エンドミル1〜3および従来被覆超硬エンドミル1〜3については、
被削材:平面寸法:100mm×250mm、厚さ:50mmのJIS・S50Cの板材、
切削速度:200m/min.、
軸方向切り込み:4mm、
径方向切り込み:0.8mm、
テーブル送り:1000mm/分、
の条件での炭素鋼の乾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4〜6および従来被覆超硬エンドミル4〜6については、
被削材:平面寸法:100mm×250mm、厚さ:50mmのJIS・SCM435の板材、
切削速度:180m/min.、
軸方向切り込み:7mm、
径方向切り込み:2.5mm、
テーブル送り:750mm/分、
の条件での合金鋼の乾式高速高切り込み側面切削加工試験、本発明被覆超硬エンドミル7,8および従来被覆超硬エンドミル7,8については、
被削材:平面寸法:100mm×250mm、厚さ:50mmのJIS・SKD61の板材、
切削速度:150m/min.、
軸方向切り込み:8mm、
径方向切り込み:5mm、
テーブル送り:350mm/分、
の条件での工具鋼の乾式高速高切り込み側面切削加工試験をそれぞれ行い、いずれの乾式側面切削加工試験でも切刃部の外周刃の逃げ面摩耗幅が使用寿命の目安とされる0.1mmに至るまでの切削長を測定した。この測定結果を表8,9にそれぞれ示した。
【0029】
【表7】
Figure 2004322279
【0030】
【表8】
Figure 2004322279
【0031】
【表9】
Figure 2004322279
【0032】
(実施例3)
上記の実施例2で製造した直径が8mm(超硬基体C−1〜C−3形成用)、13mm(超硬基体C−4〜C−6形成用)、および26mm(超硬基体C−7、C−8形成用)の3種の丸棒焼結体を用い、この3種の丸棒焼結体から、研削加工にて、溝形成部の直径×長さがそれぞれ4mm×13mm(超硬基体D−1〜D−3)、8mm×22mm(超硬基体D−4〜D−6)、および16mm×45mm(超硬基体D−7、D−8)の寸法、並びにいずれもねじれ角:30度の2枚刃形状をもった超硬基体(ドリル)D−1〜D−8をそれぞれ製造した。
【0033】
ついで、これらの超硬基体(ドリル)D−1〜D−8の切刃に、ホーニングを施し、アセトン中で超音波洗浄し、乾燥した状態で、同じく図1に示されるアークイオンプレーティング装置に装入し、上記実施例1と同一の条件で、層厚方向に沿って表10に示される目標組成のSi最高含有点とSi最低含有点とが交互に同じく表10に示される目標間隔で繰り返し存在し、かつ前記Si最高含有点から前記Si最低含有点、前記Si最低含有点から前記Si最高含有点へSi含有割合が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10に示される目標層厚の硬質被覆層を蒸着することにより、本発明被覆超硬工具としての本発明表面被覆超硬合金製ドリル(以下、本発明被覆超硬ドリルと云う)1〜8をそれぞれ製造した。
【0034】
また、比較の目的で、上記の超硬基体(ドリル)D−1〜D−8の切刃に、ホーニングを施し、アセトン中で超音波洗浄し、乾燥した状態で、同じく図2に示される通常のアークイオンプレーティング装置に装入し、上記実施例1と同一の条件で、表11に示される目標組成および目標層厚を有し、かつ厚さ方向に沿って実質的に組成変化のない(Ti,Si)N層からなる硬質被覆層を蒸着することにより、従来被覆超硬工具としての従来表面被覆超硬合金製ドリル(以下、従来被覆超硬ドリルと云う)1〜8をそれぞれ製造した。
【0035】
つぎに、上記本発明被覆超硬ドリル1〜8および従来被覆超硬ドリル1〜8のうち、本発明被覆超硬ドリル1〜3および従来被覆超硬ドリル1〜3については、
被削材:平面寸法:100mm×250mm、厚さ:50mmのJIS・SCM440の板材、
切削速度:200m/min.、
送り:0.18mm/rev、
穴深さ:8mm
の条件での合金鋼の湿式高速高送り穴あけ切削加工試験、本発明被覆超硬ドリル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・SS400の板材、
切削速度:180m/min.、
送り:0.3mm/rev、
穴深さ:16mm
の条件での構造用鋼の湿式高速高送り穴あけ切削加工試験、本発明被覆超硬ドリル7,8および従来被覆超硬ドリル7,8については、
被削材:平面寸法:100mm×250mm、厚さ:50mmのJIS・S50Cの板材、
切削速度:150m/min.、
送り:0.35mm/rev、
穴深さ:32mm
の条件での炭素鋼の湿式高速高送り穴あけ切削加工試験、をそれぞれ行い、いずれの湿式高速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10,11にそれぞれ示した。
【0036】
【表10】
Figure 2004322279
【0037】
【表11】
Figure 2004322279
【0038】
この結果得られた本発明被覆超硬工具としての本発明被覆超硬チップ1〜16、本発明被覆超硬エンドミル1〜8、および本発明被覆超硬ドリル1〜8、並びに従来被覆超硬工具としての従来被覆超硬チップ1〜16、従来被覆超硬エンドミル1〜8、および従来被覆超硬ドリル1〜8を構成する硬質被覆層について、厚さ方向に沿ってTi、Si、およびZrの含有割合ををオージェ分光分析装置を用いて測定したところ、前記本発明被覆超硬工具の硬質被覆層では、Si最高含有点とSi最低含有点とがそれぞれ目標値と実質的に同じ組成および間隔で交互に繰り返し存在し、かつ前記Si最高含有点から前記Si最低含有点、前記Si最低含有点から前記Si最高含有点へSiの含有割合がそれぞれ連続的に変化する成分濃度分布構造を有することが確認され、さらに硬質被覆層の平均層厚も目標層厚と実質的に同じ値を示した。一方、前記従来被覆超硬工具の硬質被覆層では、目標組成と実質的に同じ組成および目標層厚と実質的に同じ平均層厚を示すものの、厚さ方向に沿った組成変化は見られず、層全体に亘って均質な組成を示すものであった。
【0039】
【発明の効果】
表3〜11に示される結果から、硬質被覆層が厚さ方向に、すぐれた高温硬さと耐熱性を有するSi最高含有点と一段とすぐれた高温強度を有するSi最低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Si最高含有点から前記Si最低含有点、前記Si最低含有点から前記Si最高含有点へSi含有割合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工具は、いずれも各種の鋼や鋳鉄などの高速切削加工を、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、硬質被覆層がすぐれた耐チッピング性を発揮するのに対して、硬質被覆層が厚さ方向に沿って実質的に組成変化のない(Ti,Si)N層からなる従来被覆超硬工具においては、重切削条件での高速切削加工では前記硬質被覆層の高温強度不足が原因で、チッピングが発生し、これが原因で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高速切削加工を、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、すぐれた耐チッピング性を発揮し、長期に亘ってすぐれた耐摩耗性を示すものであるから、切削加工の省力化および省エネ化、さらに低コスト化に十分満足に対応できるものである。
【図面の簡単な説明】
【図1】この発明の被覆超硬工具を構成する硬質被覆層を形成するのに用いたアークイオンプレーティング装置を示し、(a)は概略平面図、(b)は概略正面図である。
【図2】従来被覆超硬工具を構成する硬質被覆層を形成するのに用いた通常のアークイオンプレーティング装置の概略説明図である。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides a hard coating layer having an even higher high-temperature strength and excellent high-temperature hardness and heat resistance. Regarding surface coated cemented carbide cutting tools (hereafter referred to as coated cemented carbide tools) whose hard coating layer exhibits excellent chipping resistance even under heavy cutting conditions such as high cutting and high feed with impact. Things.
[0002]
[Prior art]
In general, coated carbide tools are used for turning or flat cutting 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 also performs cutting in the same manner as the solid type end mill by detachably attaching the throw-away tip. A throw-away end mill tool and the like are known.
[0003]
Further, as a coated cemented carbide tool, a substrate made of tungsten carbide (hereinafter, referred to as WC) -based cemented carbide or titanium carbonitride (hereinafter, referred to as TiCN) -based cermet (hereinafter, these are collectively referred to as a cemented carbide substrate) ) On the surface,
Formula: (Ti 1-X Si X ) N ( provided that an atomic ratio, X is shows the 0.45 to 0.60),
Proposed a coated carbide tool formed by physical vapor deposition of a hard coating layer composed of a composite nitride of Ti and Si [hereinafter, referred to as (Ti, Si) N] with an average thickness of 0.5 to 15 μm. The coated carbide tool has various kinds of steels because the (Ti, Si) N layer constituting the hard coating layer has excellent high-temperature hardness and heat resistance by Si and excellent high-temperature strength by Ti. It is also known to be used for continuous cutting or intermittent cutting of steel or cast iron (for example, see Patent Document 1).
[0004]
Furthermore, the above-mentioned coated carbide tool is charged with the above-mentioned carbide substrate in an arc ion plating apparatus, which is a kind of physical vapor deposition apparatus shown schematically in FIG. 2, for example, and the inside of the apparatus is heated by a heater. For example, while being heated to a temperature of 400 ° C., an arc discharge is generated between the anode electrode and a cathode electrode (evaporation source) on which a Ti—Si alloy having a predetermined composition is set, for example, at a current of 90 A, At the same time, nitrogen gas is introduced as a reaction gas into the apparatus to form a reaction atmosphere of, for example, 2 Pa. On the other hand, on the surface of the super-hard substrate, a bias voltage of, for example, -200 V is applied to the surface of the super-hard substrate. It is also known to be manufactured by depositing a hard coating layer consisting of a (Ti, Si) N layer.
[0005]
[Patent Document 1]
JP-A-8-118106
[Problems to be solved by the invention]
In recent years, the performance of cutting equipment has been remarkably improved.On the other hand, there is a strong demand for labor-saving and energy-saving cutting, as well as low cost, and with this, the cutting speed has been increased, and high cutting and high feed rates have been required. Cutting under heavy cutting conditions tends to be strongly demanded, but in the above-mentioned conventional coated carbide tools, there is no problem if this is used under normal cutting conditions, but it involves high heat generation. When high-speed cutting is performed under heavy cutting conditions such as high cutting and high feed with high mechanical impact, chipping (small cracks) is likely to occur, especially due to insufficient high-temperature strength of the hard coating layer. At present, the service life is reached in hours.
[0007]
[Means for Solving the Problems]
In view of the above, the present inventors have developed the above-described conventional coated carbide tool in order to develop a coated carbide tool in which the hard coating layer exhibits excellent chipping resistance especially in high-speed heavy cutting. As a result of conducting research, focusing on the constituent hard coating layer,
(A) The (Ti, Si) N layer constituting the conventional coated carbide tool formed using the arc ion plating apparatus shown in FIG. 2 described above has a substantially uniform composition throughout its thickness. Therefore, for example, an arc ion plating apparatus having a structure shown in a schematic plan view in FIG. 1A and a schematic front view in FIG. A rotary table for mounting a substrate is provided, and a Ti—Si alloy used as a cathode electrode (evaporation source) for forming the above-mentioned conventional (Ti, Si) N layer is provided on one side of the rotary table. Is disposed as an alloy component, and on the other side, any Ti-Si-Zr alloy having a relatively low Si content compared to the Ti-Si-Zr alloy is used. Cathode electrode (evaporation A plurality of carbide bases are mounted in a ring shape along the outer periphery at a position radially away from the center axis by a predetermined distance on the rotary table of the apparatus using an arc ion plating apparatus which is opposed to the apparatus. In this state, while rotating the rotary table with the atmosphere in the apparatus being a nitrogen atmosphere, and rotating the super-hard substrate itself for the purpose of uniforming the thickness of the hard coating layer formed by vapor deposition, the cathode electrodes on the both sides are simultaneously rotated. When an arc discharge is generated between the (evaporation source) and the anode electrode to form a (Ti, Si, Zr) N layer on the surface of the superhard substrate, the resulting (Ti, Si, Zr) N layer In the above, when the cemented carbide substrate arranged in a ring shape on the rotary table comes closest to the one side Ti—Si—Zr alloy cathode electrode (evaporation source), the highest Si content point in the layer is obtained. When the cemented carbide substrate is closest to the cathode electrode of the Ti-Si-Zr alloy having a relatively low Si content on the other side, the lowest Si content point is formed in the layer. Due to the rotation of the table, the highest Si content points and lowest Si content points alternately appear at predetermined intervals in the layer along the thickness direction, and the highest Si content points and the lowest Si content points, and the lowest Si content points. A component concentration distribution structure in which the Si content ratio changes continuously from a point to the highest Si content point.
[0008]
(B) In the (Ti, Si, Zr) N layer of the concentration distribution structure of the continuously changing component of (a), the Si content in the Ti—Si—Zr alloy that is the cathode electrode (evaporation source) on one side of the opposed arrangement. The ratio is assumed to correspond to the Si content of the above-described conventional Ti-Si alloy for forming a (Ti, Si) N layer, and the Si content in the Ti-Si-Zr alloy as the cathode electrode (evaporation source) on the other side. Is relatively low compared to the Si content ratio of the above conventional Ti-Si alloy, while controlling the rotation speed of the turntable on which the carbide substrate is mounted,
The Si maximum content point, composition formula: (Ti 1- (X + Z ) Si X Zr Z) N ( provided that an atomic ratio, X is 0.45 to 0.60, Z: 0.05 to 0.15 ),
The above-mentioned minimum content point of Si is determined by the composition formula: (Ti 1- ( Y + Z ) Si Y Zr Z) N (provided that an atomic ratio, Y is 0.03 to 0.25, Y: shows the 0.05 to 0.15),
Is satisfied, and the distance in the thickness direction between the adjacent Si highest content point and the lowest Si content point is 0.01 to 0.1 μm,
The Si highest content portion has excellent high-temperature hardness and heat resistance corresponding to the high-temperature hardness and heat resistance of the conventional (Ti, Si) N layer, and has a high-temperature strength due to Ti and Zr components. On the other hand, the Si lowest content portion has a lower Si content ratio and a relatively higher Ti content ratio than the Si highest content portion, so that the Zr component has an effect of improving high-temperature strength for the Zr component. In combination with this, higher high-temperature strength is secured, and the interval between the highest Si content point and the lowest Si content point is extremely small, so that the properties of the entire layer are excellent in high-temperature hardness and heat resistance. In addition, coated carbide tools made of a (Ti, Si, Zr) N layer having a hard coating layer, which has a higher strength at a higher temperature, are particularly suitable for cutting various kinds of steel and cast iron. The hard coating layer exhibits excellent chipping resistance even when machining at high cutting speed with high heat generation and heavy cutting conditions such as high cutting and high feed with high mechanical impact. To be like that.
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 has a hard coating layer composed of a (Ti, Si, Zr) N layer having an average layer thickness of 0.5 to 15 μm on the surface of a super hard substrate. The coated hard carbide tool is formed by physical vapor deposition, and the hard coating layer is formed such that the highest Si content points and the lowest Si content points are alternately present at predetermined intervals along the layer thickness direction, and Having a component concentration distribution structure in which the Si content ratio continuously changes from the highest content point to the lowest Si content point, from the lowest Si content point to the highest Si content point,
Furthermore, the highest Si content point is
Formula: (Ti 1- (X + Z ) Si X Zr Z) N ( provided that an atomic ratio, X is 0.45 to 0.60, Z: shows the 0.05 to 0.15),
The above-mentioned Si minimum content point is
Formula: (Ti 1- (Y + Z ) Si Y Zr Z) N (provided that an atomic ratio, Y is 0.03 to 0.25, Z: shows the 0.05 to 0.15),
And the interval between adjacent Si highest content points and adjacent Si lowest content points is 0.01 to 0.1 μm,
The present invention is characterized by a coated carbide tool which is constituted by a hard coating layer and 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) Composition of highest Si content point In (Ti, Si, Zr) N having the highest Si content point, the Ti component improves high-temperature strength, the Si has high-temperature hardness and heat resistance, and the Zr component coexists with Ti. Has the effect of further improving the high-temperature strength, and therefore, the higher the Si content ratio, the higher the high-temperature hardness and heat resistance, and the higher the high-temperature cutting with high heat generation, the higher the Si content. If the X value indicating the content ratio exceeds 0.60 in the ratio (atomic ratio) to the total amount of Ti and Zr, the content ratio of the Ti component becomes relatively too low, and the Si component having excellent high-temperature strength becomes the lowest. Even if the content points are adjacent to each other, a decrease in the high-temperature strength of the layer itself is unavoidable. As a result, chipping and the like are liable to occur. Hardness and heat resistance It is difficult to ensure, since the so wear progresses rapidly, defining the X value as 0.45 to 0.60.
Further, the Zr component has the effect of improving the high-temperature strength as described above. However, if the Z value indicating the Zr content ratio is less than 0.05 in the ratio (atomic ratio) to the total amount of Si and Ti, the desired high temperature can be obtained. When the strength improvement effect is not obtained, and when the Z value exceeds 0.15, the high-temperature hardness and heat resistance tend to decrease, so the Z value is set to 0.05 to 0.15. .
[0011]
(B) Composition of lowest Si content point As described above, the highest Si content point has excellent high-temperature hardness and heat resistance due to the high content of Si component, but on the other hand, heavy cutting such as high cutting and high feed accompanied by high mechanical impact. Insufficient high-temperature strength is inevitable in high-speed cutting under conditions, and in order to compensate for the high-temperature strength shortage at the highest Si content point, the Ti content ratio is relatively high, while the Si content ratio is low, which makes it even better. The lowest Si content point having high-temperature strength is alternately interposed in the thickness direction. Therefore, the Y value indicating the ratio of Si is 0 (the atomic ratio) in the total amount of the Ti and Zr components. When the Y value is less than 0.03, it becomes difficult to secure a predetermined high-temperature hardness and heat resistance when the Y value is less than 0.03. High temperature hardness Since the wear progress of the layer itself is promoted even if the Si maximum content point having excellent heat resistance is present adjacent to the Si content point, the Y value indicating the Si content ratio at the Si minimum content point is set to 0.03. 0.20.25.
Further, the Zr component at the lowest content point of Si is also included for the purpose of improving high-temperature strength as described above and adapting to high-speed cutting accompanied by high heat generation. When the Z value exceeds 0.15, the high-temperature hardness and the heat resistance tend to decrease, which causes the wear to progress. .15.
[0012]
(C) Interval between the highest Si content point and the lowest Si content point If the interval is less than 0.01 μm, it is difficult to clearly form each point with the above composition, and as a result, the layer has Excellent high-temperature hardness and heat resistance, and further excellent high-temperature strength due to the lowest content point of Si cannot be secured, and if the distance exceeds 0.1 μm, each point will be cut by high-speed cutting under heavy cutting conditions. The disadvantages are that, at the highest Si content, the high-temperature strength is insufficient, and at the lowest Si content, the high-temperature hardness and heat resistance deficiency appear locally in the layer, causing chipping to occur or abrasion. Since the progress is promoted, the interval is set to 0.01 to 0.1 μm.
[0013]
(D) Average Layer Thickness of Hard Coating Layer If the average layer thickness is less than 0.5 μm, desired wear resistance cannot be ensured, while if the average layer thickness exceeds 15 μm, chipping is likely to occur. Therefore, the average layer thickness was determined to be 0.5 to 15 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.
(Example 1)
As raw material powders, WC powder, TiC powder, VC powder, TaC powder, NbC powder, Cr 3 C 2 powder, and Co powder each having an average particle diameter of 1 to 3 μm were prepared. The mixture was wet-mixed with a ball mill for 48 hours, dried, and then pressed into a green compact at a pressure of 100 MPa, and the green compact was heated at a temperature of 1420 ° 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 a honing process of R: 0.03, and a cemented carbide substrate A-1 made of a WC-based cemented carbide having a chip shape of ISO standard CNMG120412. ~ A-10 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 for 72 hours in a ball mill, dried, and then pressed into a green compact at a pressure of 100 MPa. This compact was sintered in a 2 kPa nitrogen atmosphere at a temperature of 1520 ° C. for 1 hour, and after sintering, the cutting edge was subjected to a honing process of R: 0.03 to conform to ISO standard CNMG120412. Carbide bases B-1 to B-6 made of TiCN-based cermet having the chip shape described above were formed.
[0016]
Next, each of the above-mentioned super-hard substrates A-1 to A-10 and B-1 to B-6 is subjected to ultrasonic cleaning in acetone, and dried, in an arc ion plating apparatus shown in FIG. A plurality of carbide substrates are mounted in a ring shape along the outer peripheral portion at a position radially away from the central axis at a predetermined distance from the rotary table, and various component compositions are used as a cathode electrode (evaporation source) on one side. A Ti-Si-Zr alloy for forming the highest Si content point, and a Ti-Si-Zr alloy for forming the lowest Si content point as the cathode electrode (evaporation source) on the other side, facing the rotary table, First, the inside of the apparatus is heated to 500 ° C. with the heater while the inside of the apparatus is evacuated and maintained at a vacuum of 0.5 Pa or less, and then rotated while rotating on the rotary table. Carbide group , A DC bias voltage of -1000 V is applied, and a current of 100 A is caused to flow between the metal Ti of the cathode electrode and the anode electrode to generate an arc discharge, thereby cleaning the surface of the cemented carbide substrate with Ti bombardment. Nitrogen gas was introduced as a reaction gas into the inside of the reactor to form a reaction atmosphere of 3 Pa, and a DC bias voltage of -30 V was applied to the superhard substrate rotating while rotating on the rotary table, and the respective cathode electrodes (the A current of 150 A is caused to flow between the anode electrode and the Ti-Si-Zr alloy for forming the highest Si content point and the Ti-Si-Zr alloy for forming the lowest Si content point to generate an arc discharge. On the surface of the target, along the thickness direction, the highest Si content and the lowest Si content of the target compositions shown in Tables 3 and 4 are alternately shown in Tables 3 and 4 Having a component concentration distribution structure that is present repeatedly at a target interval, and the Si content ratio continuously changes from the Si highest content point to the Si lowest content point, the Si lowest content point to the Si highest content point, and Similarly, by depositing a hard coating layer having a target layer thickness shown in Tables 3 and 4, a throw-away tip made of the surface-coated cemented carbide of the present invention as a coated carbide tool of the present invention (hereinafter referred to as the coated cemented carbide tip of the present invention) 1-16 were produced respectively.
[0017]
For the purpose of comparison, these super-hard substrates A-1 to A-10 and B-1 to B-6 were ultrasonically cleaned in acetone and dried, and the normal arc shown in FIG. It is charged into an ion plating apparatus, Ti-Si alloys having various component compositions are mounted as a cathode electrode (evaporation source), and metal Ti for bombarding is also mounted. After heating the inside of the apparatus to 400 ° C. with a heater while maintaining a vacuum of 0.5 Pa or less, a DC bias voltage of −1000 V is applied to the super-hard substrate, and a voltage is applied between the metal Ti of the cathode electrode and the anode electrode. A current of 90 A was applied to generate arc discharge, and the surface of the super-hard substrate was cleaned with Ti bombard. Then, nitrogen gas was introduced as a reaction gas into the apparatus to obtain a reaction atmosphere of 2 Pa. The bias voltage applied to the hard substrate is reduced to -200 V to generate an arc discharge between the cathode electrode and the anode electrode, whereby the super hard substrates A-1 to A-10 and B-1 to B-6 are generated. A hard coating layer composed of a (Ti, Si) N layer having a target composition and a target layer thickness shown in Table 5 and having substantially no composition change along the thickness direction is deposited on each surface of the substrate. Thus, conventional surface-coated cemented carbide throwaway tips (hereinafter, referred to as conventionally-coated cemented carbide tips) 1 to 16 as conventionally-coated cemented carbide tools were respectively manufactured.
[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 S45C round bar,
Cutting speed: 320 m / min. ,
Cut: 4.5 mm,
Feed: 0.3 mm / rev. ,
Cutting time: 10 minutes,
Dry continuous high-speed cutting test of carbon steel under the following conditions:
Work material: Round bar with four vertical grooves at equal intervals in the length direction of JIS / FC300
Cutting speed: 300 m / min. ,
Cut: 2.5mm,
Feed: 0.6 mm / rev. ,
Cutting time: 5 minutes,
Intermittent high-speed high-feed cutting test of cast iron under the following conditions,
Work material: JIS SNCM439 round bar,
Cutting speed: 350 m / min. ,
Cut: 5mm,
Feed: 0.2 mm / rev. ,
Cutting time: 10 minutes,
A dry continuous high-speed, high-cut cutting test was performed on the alloy steel under the following conditions, and the flank wear width of the cutting edge was measured in each cutting test. Table 6 shows the measurement results.
[0019]
[Table 1]
Figure 2004322279
[0020]
[Table 2]
Figure 2004322279
[0021]
[Table 3]
Figure 2004322279
[0022]
[Table 4]
Figure 2004322279
[0023]
[Table 5]
Figure 2004322279
[0024]
[Table 6]
Figure 2004322279
[0025]
(Example 2)
As raw material powders, medium coarse WC powder having an average particle diameter of 5.5 μm, fine WC powder of 0.8 μm, TaC powder of 1.3 μm, NbC powder of 1.2 μm, and ZrC of 1.2 μm Powder, 2.3 μm Cr 3 C 2 powder, 1.5 μm VC powder, 1.0 μm (Ti, W) C powder, and 1.8 μm Co powder were prepared. Each was blended into the blending composition shown in Table 7, and further added with wax, ball-milled in acetone for 50 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 in a vacuum atmosphere of 6 Pa at a heating rate of 7 ° C./min to a predetermined temperature in the range of 1370 to 1470 ° C., and is kept at this temperature for 1 hour, and then fired under furnace cooling conditions. In combination, diameters of 8 mm, 13 mm, and 2 mm mm, three types of round bar sintered bodies for forming a cemented carbide substrate are formed, and the above three types of round bar sintered bodies are subjected to grinding processing in a combination shown in Table 7 to obtain a diameter of a cutting edge portion. × Carbide substrates (end mills) C-1 to C-8 each having dimensions of 6 mm × 13 mm, 10 mm × 22 mm, and 20 mm × 45 mm, and a four-flute square shape with a twist angle of 30 °. Was manufactured respectively.
[0026]
Then, these super-hard substrates (end mills) C-1 to C-8 were ultrasonically cleaned in acetone, dried, and charged into an arc ion plating apparatus also shown in FIG. Under the same conditions as in Example 1, the highest Si content points and lowest Si content points of the target compositions shown in Table 8 are alternately and repeatedly present at the target intervals shown in Table 8 along the layer thickness direction, and It has a component concentration distribution structure in which the Si content ratio changes continuously from the highest Si content point to the lowest Si content point, and the lowest Si content point to the highest Si content point, and the target layer thickness also shown in Table 8 By depositing a hard coating layer of the present invention, end mills 1 to 8 made of the surface-coated cemented carbide of the present invention (hereinafter referred to as coated carbide end mills of the present invention) as coated carbide tools of the present invention were produced.
[0027]
For the purpose of comparison, the above-mentioned ultra-hard substrates (end mills) C-1 to C-8 were ultrasonically cleaned in acetone and dried, and then a normal arc ion plating apparatus also shown in FIG. (Ti, Si) N having the target composition and the target layer thickness shown in Table 9 and having substantially no composition change along the thickness direction under the same conditions as in Example 1 above. By depositing a hard coating layer composed of layers, end mills made of conventional surface-coated cemented carbide (hereinafter referred to as conventional coated carbide end mills) 1 to 8 as conventional coated cemented carbide tools were manufactured, respectively.
[0028]
Next, among the coated carbide end mills 1 to 8 of the present invention and the conventional coated carbide end mills 1 to 8, of the coated carbide end mills 1 to 3 and the coated carbide end mills 1 to 3 of the present invention,
Work material: Plane dimensions: 100 mm x 250 mm, thickness: 50 mm JIS S50C plate,
Cutting speed: 200 m / min. ,
Axial cut: 4mm,
Radial cut: 0.8mm,
Table feed: 1000 mm / min,
For the dry high-speed and high-feed side milling test of carbon steel under the following conditions, the coated carbide end mills 4 to 6 of the present invention and the conventionally coated carbide end mills 4 to 6,
Work material: Plane dimensions: 100 mm x 250 mm, thickness: 50 mm, JIS SCM435 plate,
Cutting speed: 180 m / min. ,
Axial cut: 7mm,
Radial cut: 2.5mm,
Table feed: 750 mm / min,
The dry-type high-speed high-cut side-cutting test of the alloy steel under the following conditions, the coated carbide end mills 7, 8 of the present invention and the conventional coated carbide end mills 7, 8 are as follows.
Work material: Plane dimensions: 100 mm x 250 mm, thickness: 50 mm, JIS SKD61 plate,
Cutting speed: 150 m / min. ,
Axial cut: 8mm
Radial cut: 5mm
Table feed: 350 mm / min.
In each of the dry side cutting tests, the flank wear width of the outer peripheral edge of the cutting edge was reduced to 0.1 mm, which is a guide for the service life. The cutting length up to was measured. The measurement results are shown in Tables 8 and 9, respectively.
[0029]
[Table 7]
Figure 2004322279
[0030]
[Table 8]
Figure 2004322279
[0031]
[Table 9]
Figure 2004322279
[0032]
(Example 3)
The diameters produced in Example 2 were 8 mm (for forming the super-hard substrates C-1 to C-3), 13 mm (for forming the super-hard substrates C-4 to C-6), and 26 mm (for the super-hard substrates C-). 7, for forming C-8), the diameter x length of the groove forming portion was 4 mm x 13 mm (by grinding) from the three types of round rod sintered bodies by grinding. Carbide substrates D-1 to D-3), dimensions of 8 mm x 22 mm (carbide substrates D-4 to D-6), and 16 mm x 45 mm (carbide substrates D-7 and D-8), and any of them Carbide substrates (drills) D-1 to D-8 each having a two-blade shape with a twist angle of 30 degrees were manufactured.
[0033]
Next, the cutting blades of the super hard substrates (drills) D-1 to D-8 are honed, ultrasonically cleaned in acetone, and dried, and then the arc ion plating apparatus shown in FIG. Under the same conditions as in Example 1 described above, and the Si maximum content points and the Si minimum content points of the target compositions shown in Table 10 are alternately arranged along the layer thickness direction in the same manner as in Example 10. And a component concentration distribution structure in which the Si content ratio continuously changes from the highest Si content point to the lowest Si content point, from the lowest Si content point to the highest Si content point, and By depositing a hard coating layer having a target layer thickness shown in 10, drills made of the surface-coated cemented carbide of the present invention (hereinafter, referred to as coated carbide drills of the present invention) 1 to 8 as coated carbide tools of the present invention. Each was manufactured.
[0034]
Also, for comparison purposes, the cutting edges of the above-mentioned carbide substrates (drills) D-1 to D-8 are honed, ultrasonically cleaned in acetone, and dried, and are also shown in FIG. It was charged in a normal arc ion plating apparatus, and had the target composition and the target layer thickness shown in Table 11 under the same conditions as in Example 1 above, and the composition change substantially along the thickness direction. By depositing a hard coating layer consisting of a non-coated (Ti, Si) N layer, conventional surface-coated carbide alloy drills (hereinafter referred to as conventional coated carbide drills) 1 to 8 as conventional coated carbide tools are respectively provided. Manufactured.
[0035]
Next, of the coated carbide drills 1 to 8 of the present invention and the coated carbide drills 1 to 8 of the related art, the coated carbide drills 1 to 3 of the present invention and the covered carbide drills 1 to 3 of the present invention are:
Work material: Plane dimensions: 100 mm x 250 mm, thickness: 50 mm JIS SCM440 plate,
Cutting speed: 200 m / min. ,
Feed: 0.18 mm / rev,
Hole depth: 8mm
For the wet-type high-speed and high-feed drilling cutting test of the alloy steel under the conditions described below, the coated carbide drills 4 to 6 of the present invention and the conventionally coated carbide drills 4 to 6 are as follows.
Work material: Plane dimensions: 100 mm x 250 mm, thickness: 50 mm, JIS SS400 plate,
Cutting speed: 180 m / min. ,
Feed: 0.3 mm / rev,
Hole depth: 16mm
For the wet-type high-speed and high-feed drilling cutting test of structural steel under the following conditions, the coated carbide drills 7 and 8 of the present invention and the conventionally coated carbide drills 7 and 8,
Work material: Plane dimensions: 100 mm x 250 mm, thickness: 50 mm JIS S50C plate,
Cutting speed: 150 m / min. ,
Feed: 0.35 mm / rev,
Hole depth: 32mm
Welding high-speed high-drilling cutting test of carbon steel under the conditions described above was performed, and in all wet high-speed drilling cutting tests (using water-soluble cutting oil), the flank wear width of the tip cutting edge surface was reduced to 0.3 mm. The number of drilling operations up to that point was measured. The measurement results are shown in Tables 10 and 11, respectively.
[0036]
[Table 10]
Figure 2004322279
[0037]
[Table 11]
Figure 2004322279
[0038]
The coated carbide tips 1-16, coated carbide end mills 1-8, coated drills 1-8, and coated carbide tools of the present invention as the coated carbide tools of the present invention obtained as a result. As for the hard coating layers constituting the conventional coated carbide tips 1 to 16, the conventional coated carbide end mills 1 to 8 and the conventional coated carbide drills 1 to 8, Ti, Si, and Zr along the thickness direction. When the content ratio was measured using an Auger spectrometer, in the hard coating layer of the coated carbide tool of the present invention, the highest Si content point and the lowest Si content point had substantially the same composition and spacing as the target values, respectively. And a component concentration distribution structure in which the Si content ratio continuously changes from the highest Si content point to the lowest Si content point and from the lowest Si content point to the highest Si content point. It was confirmed to have further the average layer thickness of the hard layer shown the target layer thickness substantially the same value. On the other hand, in the hard coating layer of the conventional coated carbide tool, although the composition is substantially the same as the target composition and the average layer thickness is substantially the same as the target layer thickness, no change in the composition along the thickness direction is observed. And a homogeneous composition throughout the layer.
[0039]
【The invention's effect】
From the results shown in Tables 3 to 11, the hard coating layer has a predetermined interval in the thickness direction in which the Si highest content point having excellent high-temperature hardness and heat resistance and the Si lowest content point having further excellent high-temperature strength are alternately arranged at predetermined intervals. The present invention coating having a component concentration distribution structure in which the Si content ratio is repeatedly present and the Si content ratio continuously changes from the highest Si content point to the lowest Si content point, and from the lowest Si content point to the highest Si content point. Carbide tools have excellent chipping resistance even when high-speed cutting of various types of steel or cast iron is performed under heavy cutting conditions such as high cutting and high feed with high mechanical impact. On the other hand, in the case of a conventional coated carbide tool in which the hard coating layer is composed of a (Ti, Si) N layer having substantially no composition change along the thickness direction, high-speed cutting under heavy cutting conditions In processing, the hard Hot insufficient strength of the coating layer is caused, chipping occurs and this is apparent that lead to a relatively short time service life due.
As described above, the coated cemented carbide tool of the present invention can be used not only for cutting under normal conditions, but also for high-speed cutting of various types of steel and cast iron, for example, at high cutting and high feed rates with high mechanical impact. Even when performed under heavy cutting conditions such as high cutting resistance, it exhibits excellent chipping resistance and exhibits excellent wear resistance over a long period of time. Can be fully satisfied.
[Brief description of the drawings]
FIG. 1 shows an arc ion plating apparatus used for forming a hard coating layer constituting a coated carbide tool of the present invention, wherein (a) is a schematic plan view and (b) is a schematic front view.
FIG. 2 is a schematic explanatory view of a conventional arc ion plating apparatus used for forming a hard coating layer constituting a conventional coated carbide tool.

Claims (1)

炭化タングステン基超硬合金基体または炭窒化チタン系サーメット基体の表面に、TiとSiとZrの複合窒化物層からなる硬質被覆層を0.5〜15μmの全体平均層厚で物理蒸着してなる表面被覆超硬合金製切削工具にして、
上記硬質被覆層を、層厚方向にそって、Si最高含有点とSi最低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Si最高含有点から前記Si最低含有点、前記Si最低含有点から前記Si最高含有点へSi含有割合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Si最高含有点が、組成式:(Ti1−(X+ SiZr)N(ただし、原子比で、Xは0.45〜0.60、Z:0.05〜0.15を示す)、
上記Si最低含有点が、組成式:(Ti1−( Si Zr)N(ただし、原子比で、Yは0.03〜0.25、Z:0.05〜0.15を示す)、
を満足し、かつ隣り合う上記Si最高含有点とSi最低含有点の間隔が、0.01〜0.1μmである、
硬質被覆層で構成した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 hard coating layer consisting of a composite nitride layer of Ti, Si and Zr is physically deposited 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 0.5 to 15 μm. Surface coated cemented carbide cutting tools,
In the hard coating layer, the Si highest content point and the Si lowest content point alternately and repeatedly exist at predetermined intervals along the layer thickness direction, and the Si highest content point and the Si lowest content point, Having a component concentration distribution structure in which the Si content ratio changes continuously from the lowest content point to the highest Si content point,
Furthermore, the Si maximum content point, composition formula: (Ti 1- (X + Z ) Si X Zr Z) N ( provided that an atomic ratio, X is 0.45 to 0.60, Z: from 0.05 to 0 .15),
The above-mentioned minimum content point of Si is determined by the composition formula: (Ti 1- ( Y + Z ) Si Y Zr Z) N (provided that an atomic ratio, Y is 0.03 to 0.25, Z: shows the 0.05 to 0.15),
And the interval between adjacent Si highest content points and adjacent Si lowest content points is 0.01 to 0.1 μm,
A cutting tool made of a surface-coated cemented carbide in which the hard coating layer exhibits excellent chipping resistance under high-speed heavy cutting conditions characterized by comprising a hard coating layer.
JP2003123256A 2003-04-28 2003-04-28 Cutting tool made of surface-coated cemented carbide that exhibits excellent chipping resistance under high-speed heavy cutting conditions. Expired - Fee Related JP4366987B2 (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011020194A (en) * 2009-07-14 2011-02-03 Sumitomo Electric Ind Ltd Surface-coated cutting tool
US8389115B2 (en) 2008-03-07 2013-03-05 Seco Tools Ab Thermally stabilized (Ti,Si)N layer for cutting tool insert
WO2013131943A1 (en) 2012-03-07 2013-09-12 Seco Tools Ab A body with a metal based nitride layer and a method for coating the body

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8389115B2 (en) 2008-03-07 2013-03-05 Seco Tools Ab Thermally stabilized (Ti,Si)N layer for cutting tool insert
JP2011020194A (en) * 2009-07-14 2011-02-03 Sumitomo Electric Ind Ltd Surface-coated cutting tool
WO2013131943A1 (en) 2012-03-07 2013-09-12 Seco Tools Ab A body with a metal based nitride layer and a method for coating the body

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