JP4461407B2 - Cutting tool made of surface-coated cemented carbide with excellent chipping resistance in high-speed intermittent cutting - Google Patents
Cutting tool made of surface-coated cemented carbide with excellent chipping resistance in high-speed intermittent cutting Download PDFInfo
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- 238000005520 cutting process Methods 0.000 title claims description 47
- 239000010410 layer Substances 0.000 claims description 95
- 239000011247 coating layer Substances 0.000 claims description 27
- 239000010936 titanium Substances 0.000 claims description 17
- 239000012495 reaction gas Substances 0.000 claims description 16
- 239000000203 mixture Substances 0.000 claims description 14
- 239000013078 crystal Substances 0.000 claims description 12
- 229910052719 titanium Inorganic materials 0.000 claims description 11
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 10
- 229910052799 carbon Inorganic materials 0.000 claims description 6
- 238000005229 chemical vapour deposition Methods 0.000 claims description 6
- 239000000758 substrate Substances 0.000 claims description 6
- 150000001875 compounds Chemical class 0.000 claims description 4
- 230000007423 decrease Effects 0.000 claims description 4
- NRTOMJZYCJJWKI-UHFFFAOYSA-N Titanium nitride Chemical compound [Ti]#N NRTOMJZYCJJWKI-UHFFFAOYSA-N 0.000 claims description 3
- 239000007789 gas Substances 0.000 claims description 3
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 2
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims description 2
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 claims description 2
- MTPVUVINMAGMJL-UHFFFAOYSA-N trimethyl(1,1,2,2,2-pentafluoroethyl)silane Chemical compound C[Si](C)(C)C(F)(F)C(F)(F)F MTPVUVINMAGMJL-UHFFFAOYSA-N 0.000 claims description 2
- UONOETXJSWQNOL-UHFFFAOYSA-N tungsten carbide Chemical compound [W+]#[C-] UONOETXJSWQNOL-UHFFFAOYSA-N 0.000 claims description 2
- 239000003610 charcoal Substances 0.000 claims 1
- FOZHTJJTSSSURD-UHFFFAOYSA-J titanium(4+);dicarbonate Chemical compound [Ti+4].[O-]C([O-])=O.[O-]C([O-])=O FOZHTJJTSSSURD-UHFFFAOYSA-J 0.000 claims 1
- 239000000843 powder Substances 0.000 description 9
- 230000000694 effects Effects 0.000 description 7
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 4
- 229910001018 Cast iron Inorganic materials 0.000 description 4
- 229910000831 Steel Inorganic materials 0.000 description 4
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 4
- 239000010959 steel Substances 0.000 description 4
- 239000000470 constituent Substances 0.000 description 3
- 238000011160 research Methods 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000011229 interlayer Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 229910000851 Alloy steel Inorganic materials 0.000 description 1
- 229910001141 Ductile iron Inorganic materials 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 239000011812 mixed powder Substances 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 238000004611 spectroscopical analysis Methods 0.000 description 1
- 229910052715 tantalum Inorganic materials 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
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Description
【０００１】
【発明の属する技術分野】
この発明は、硬質被覆層を構成する縦長成長結晶組織の炭窒化チタン層（以下、ｌ−ＴｉＣＮで示す）が一段とすぐれた耐チッピング性を有し、特に鋼や鋳鉄などの断続切削を高速で行った場合にも、切刃にチッピング（微小欠け）などの発生なく、すぐれた切削性能を長期に亘って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】
従来、一般に、炭化タングステン基超硬合金基体（以下、超硬基体という）の表面に、
（ａ） いずれも０．１〜５μｍの平均層厚および粒状結晶組織を有する、炭化チタン（以下、ＴｉＣで示す）層、窒化チタン（以下、同じくＴｉＮで示す）層、炭窒化チタン（以下、ＴｉＣＮで示す）層、酸化チタン（以下、Ｔｉ2 Ｏ3 で示す）層、炭酸化チタン（以下、ＴｉＣＯで示す）層、窒酸化チタン（以下、ＴｉＮＯで示す）層、および炭窒酸化チタン（以下、ＴｉＣＮＯで示す）層のうちの１種または２種以上からなるＴｉ化合物層と、
（ｂ） ２〜１５μｍの平均層厚のｌ−ＴｉＣＮ層と、
（ｃ） ０．５〜８μｍの平均層厚および粒状結晶組織を有する酸化アルミニウム（以下、Ａｌ2 Ｏ3 で示す）層と、
で構成された硬質被覆層を３〜２５μｍの全体平均層厚で化学蒸着してなる被覆超硬工具が知られており、またこの被覆超硬工具が鋼や鋳鉄などの連続切削や断続切削に用いられることも知られている。
また、一般に上記の被覆超硬工具の硬質被覆層を構成するＡｌ2 Ｏ3 層として、α型結晶構造をもつものやκ型結晶構造をもつものなどが広く実用に供されることも良く知られており、さらに上記ｌ−ＴｉＣＮ層は、例えば特開平６−８０１０号公報や特開平７−３２８８０８号公報などにより公知であり、通常の化学蒸着装置にて、反応ガスとして有機炭窒化物を含む混合ガスを使用し、７００〜９５０℃の中温温度域で化学蒸着することにより形成されるものである。
【０００３】
【発明が解決しようとする課題】
一方、近年の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にあるが、上記の従来被覆超硬工具においては、これの硬質被覆層を構成するｌ−ＴｉＣＮ層が相対的に良好な靭性を具備することから、これによって硬質被覆層も良好な靭性をもつようになり、通常の条件での連続切削や断続切削では切刃にチッピングなどの発生なく、すぐれた切削性能を発揮するものであるが、切削条件が一段と苛酷になる、断続切削を高速で行った場合には、未だ十分な靭性を具備するものでないために、切刃にチッピングが発生するのが避けられず、比較的短時間で使用寿命に至るのが現状である。
【０００４】
【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、上記の従来被覆超硬工具の硬質被覆層を構成するｌ−ＴｉＣＮ層に着目し、これの靭性向上を図るべく研究を行った結果、
ｌ−ＴｉＣＮ層の蒸着形成に際して、上面部形成にＴｉＣｌ ４ ，Ｎ ２ ，ＣＨ ３ ＣＮ，およびＨ ２ の構成成分からなる反応ガス、下面部形成にＴｉＣｌ ４ ，Ｎ ２ ，ＣＨ ４ ，ＣＨ ３ ＣＮ，およびＨ ２ の構成成分からなる反応ガスを用い、上面部形成では反応ガス中のＮ ２ およびＣＨ ３ ＣＮ、下面部形成では反応ガス中のＮ ２ ，ＣＨ ４ およびＣＨ ３ ＣＮの含有割合を経時的に無段階あるいは段階的に変化させることにより、ｌ−ＴｉＣＮ層に、これの下面部から上面部に向かって層厚にそってＣ成分が低く、Ｎ成分が高くなる濃度勾配を付与し、この濃度勾配を、上記上面部および下面部を組成式：ＴｉＣ1-x Ｎx で現した場合、原子比で、
上記上面部は、ｘ：０．４５〜０．６０、
上記下面部は、ｘ：０．０５〜０．３０、
を満足（この場合ＣおよびＮの下面部から上面部への濃度変化は無段階変化あるいは段階的変化となる）するようにすると、この結果のｌ−ＴｉＣＮ層（以下、濃度勾配ｌ−ＴｉＣＮ層と云う）は、下面部から上面部までＣおよびＮに濃度変化のない一様な従来ｌ−ＴｉＣＮ層に比して、すぐれた靭性を具備するようになり、したがって前記濃度勾配ｌ−ＴｉＣＮ層が硬質被覆層を構成する被覆超硬工具は、前記濃度勾配ｌ−ＴｉＣＮ層によって前記硬質被覆層自体の靭性がさらに向上するようになることから、断続切削を高速で行うという、苛酷な切削条件でも切刃にチッピングの発生なく、すぐれた切削性能を発揮するようになるという研究結果を得たのである。
【０００５】
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、
（ａ） いずれも０．１〜５μｍの平均層厚および粒状結晶組織を有する、ＴｉＣ層、ＴｉＮ層、ＴｉＣＮ層、Ｔｉ2 Ｏ3 層、ＴｉＣＯ層、ＴｉＮＯ層、およびＴｉＣＮＯ層のうちの１種または２種以上からなるＴｉ化合物層と、
（ｂ） ２〜１５μｍの平均層厚のｌ−ＴｉＣＮ層と、
（ｃ） ０．５〜８μｍの平均層厚および粒状結晶組織を有するＡｌ2 Ｏ3 層と、
で構成された硬質被覆層を３〜２５μｍの全体平均層厚で化学蒸着してなる被覆超硬工具において、
上記硬質被覆層を構成するｌ−ＴｉＣＮ層を、
下面部形成にはＴｉＣｌ ４ ，Ｎ ２ ，ＣＨ ４ ，ＣＨ ３ ＣＮ，およびＨ ２ の構成成分からなる反応ガス、上面部形成にはＴｉＣｌ ４ ，Ｎ ２ ，ＣＨ ３ ＣＮ，およびＨ ２ の構成成分からなる反応ガスを用い、かつ、前記下面部形成には前記反応ガス中のＮ ２ ，ＣＨ ４ ，およびＣＨ ３ ＣＮの含有割合を、また前記上面部形成には前記反応ガス中のＮ ２ およびＣＨ ３ ＣＮの含有割合を経時的に無段階あるいは段階的に変化させて、下面部から上面部に向かって層厚にそってＣ成分が低く、Ｎ成分が高くなり、かつ、前記ＣおよびＮの濃度が無段階変化または段階変化する濃度勾配を具備せしめると共に、前記これの上面部および下面部を組成式：ＴｉＣ1-x Ｎx で現した場合、原子比で、
上記上面部は、ｘ：０．４５〜０．６０、
上記下面部は、ｘ：０．０５〜０．３０、
を満足するｌ−ＴｉＣＮ層で構成してなる、高速断続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に特徴を有するものである。
【０００６】
なお、この発明の被覆超硬工具の硬質被覆層を構成する濃度勾配ｌ−ＴｉＣＮ層の組成式：ＴｉＣ1-x Ｎx において、上記上面部のｘ値を０．４５〜０．６０、望ましくは０．５０〜０．５５、下面部のｘ値を０．０５〜０．３０としたのは、上面部のｘ値が０．４５未満になったり、下面部のｘ値が０．３０を越えたりすると、層厚方向のＣおよびＮの濃度勾配が小さくなって、硬質被覆層が高速断続切削で所望の耐チッピング性を発揮するのに十分な靭性向上効果が得られず、一方上面部のｘ値が０．６０を越えても、高速断続切削での耐チッピング性により一段の向上効果が現われず、また下面部のｘ値が０．０５未満になると、均質な縦長成長結晶組織の安定的形成が損なわれるようになるという理由に基くものである。
【０００７】
同じく硬質被覆層を構成するＴｉ化合物層のそれぞれには、構成層相互間の層間密着性を向上させる作用があり、したがってその平均層厚が０．１μｍ未満では、所望のすぐれた層間密着性を確保することができず、一方その平均層厚が５μｍを越えると硬質被覆層の摩耗進行が促進されるようになることから、その平均層厚を０．１〜５μｍと定めた。
同じくＡｌ2 Ｏ3 層には、硬質被覆層の耐摩耗性を向上させる作用があるが、その平均層厚が０．５μｍ未満では、所望のすぐれた耐摩耗性を確保することができず、一方その平均層厚が８μｍを越えると切刃にチッピングが発生し易くなることから、その平均層厚を０．５〜８μｍと定めた。
さらに同じく濃度勾配ｌ−ＴｉＣＮ層には、上記の通り高速断続切削で硬質被覆層の耐チッピング性を向上させる作用があるが、その平均層厚が２μｍ未満では、耐チッピング性に所望の向上効果が得られず、一方その平均層厚が１５μｍを越えると耐摩耗性が急激に低下するようになることから、その平均層厚を２〜１５μｍと定めた。
また、硬質被覆層の全体平均層厚を３〜２５μｍとしたのは、その平均層厚が３μｍ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２５μｍを越えると、切刃に欠けやチッピングが発生し易くなるという理由からである。
【０００８】
【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、平均粒径：１．５μｍ有する細粒ＷＣ粉末、３．０μｍの中粒ＷＣ粉末同１．２μｍの（Ｔｉ，Ｗ）ＣＮ（重量比で、以下同じ、ＴｉＣ／ＴｉＮ／ＷＣ＝２４／２０／５６）粉末、同１．３μｍの（Ｔａ，Ｎｂ）Ｃ（ＴａＣ／ＮｂＣ＝９０／１０）粉末、同１μｍのＣｒ3 Ｃ2 粉末、同１．２μｍのＶＣ粉末、および同１．２μｍの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、この混合粉末をＩＳＯ規格ＣＮＭＧ１２０４０８に則した形状の圧粉体にプレス成形し、この圧粉体を１０-3ｔｏｒｒの真空雰囲気中、１４００〜１４６０℃の範囲内の所定の温度に１時間保持の条件で真空焼結することにより超硬基体Ａ〜Ｆをそれぞれ製造した。
【０００９】
ついで、これらの超硬基体Ａ〜Ｆの表面に、ホーニング加工を施した状態で、通常の化学蒸着装置を用い、表２、３（表２に示される硬質被覆層の構成層は、いずれも層の下面部から上面部まで構成成分に濃度変化のない一様な組成をもつものであり、またｌ−ＴｉＣＮ層以外はいずれも粒状結晶組織を有するものである）に示される条件にて、表４、５に示される組成および目標層厚（切刃の逃げ面）の硬質被覆層を形成することにより本発明被覆超硬工具１〜８および従来被覆超硬工具１〜８をそれぞれ製造した。
なお、表４における、例えば本発明被覆超硬工具３の「ｌ−ＴｉＣＮ−カ［２段階］ｌ−ＴｉＣＮ−３（４．０）」は、表３の「下面部・ｌ−ＴｉＣＮ−カ（目標ｘ値：０．３０）」の反応ガス組成から「上面部・ｌ−ＴｉＣＮ−３（目標ｘ値：０．５５）」の反応ガス組成まで反応ガス中のＣＨ3 ＣＮ、またはＣＨ3 ＣＮとＣＨ4 の含有割合を経時的に２段階変化させて４．０μｍの目標層厚で濃度勾配ｌ−ＴｉＣＮ層を形成した場合を示すものであり、同じく本発明被覆超硬工具７の「ｌ−ＴｉＣＮ−オ［連続］ｌ−ＴｉＣＮ−４（６．６）」は、「下面部・ｌ−ＴｉＣＮ−オ（目標ｘ値：０．２５）」の反応ガス組成から「上面部・ｌ−ＴｉＣＮ−４（目標ｘ値：０．６０）」の反応ガス組成まで反応ガス中のＣＨ3 ＣＮ、またはＣＨ3 ＣＮとＣＨ4 の含有割合を経時的に無段階で変化させて６．６μｍの目標層厚で濃度勾配ｌ−ＴｉＣＮ層を形成した場合を示すものである。
この結果得られた本発明被覆超硬工具１〜８の硬質被覆層を構成す濃度勾配ｌ−ＴｉＣＮ層の上面部および下面部のｘ値について、それぞれの表面から０．２μｍ内側をオージェ分光分析器を用いて測定したところ、表３に示される目標ｘ値と実質的に同じｘ値を示した。また、硬質被覆層を構成する構成層もそれぞれ目標層厚と実質的に同じ平均層厚を示した。
【００１０】
つぎに、上記本発明被覆超硬工具１〜８および従来被覆超硬工具１〜８について、
被削材：ＳＣＭ４４０の長さ方向等間隔４本縦溝入り丸棒、
切削速度：３５０ｍ／ｍｉｎ、
切り込み：１．５ｍｍ、
送り：０．２５ｍｍ／ｒｅｖ、
切削時間：１０分、
の条件での合金鋼の乾式高速断続切削試験、並びに、
被削材：ＦＣＤ４５０の長さ方向等間隔４本縦溝入り丸棒、
切削速度：３５０ｍ／ｍｉｎ、
切り込み：１．５ｍｍ、
送り：０．３２ｍｍ／ｒｅｖ、
切削時間：１０分、
の条件での球状黒鉛鋳鉄の乾式高速断続切削試験行い、いずれの切削試験でも切刃の最大逃げ面摩耗幅を測定した。この測定結果を表６に示した。
【００１１】
【表１】
【表２】
【表３】
【表４】
【表５】
【表６】
【発明の効果】
表４〜６に示される結果から、硬質被覆層中に濃度勾配ｌ−ＴｉＣＮ層が存在する本発明被覆超硬工具１〜８は、いずれも前記濃度勾配ｌ−ＴｉＣＮ層によって硬質被覆層がすぐれた靭性を具備するようになることから、鋼や鋳鉄の断続切削を高速で行なっても切刃にチッピングの発生なく、すぐれた切削性能を発揮するのに対して、硬質被覆層を構成するｌ−ＴｉＣＮ層のＣおよびＮに濃度勾配のない従来被覆超硬工具１〜８においては、上記の高速断続切削では硬質被覆層の靭性不足が原因で切刃にチッピングが発生し、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、これを構成する硬質被覆層がすぐれた耐チッピング性を有するので、例えば鋼や鋳鉄などの通常の条件での連続切削や断続切削は勿論のこと、特に断続切削を高速で行なった場合にも、長期に亘ってすぐれた切削性能を発揮するものであるから、切削加工の省力化および省エネ化、さらに低コスト化に十分満足に対応できるものである。[0001]
BACKGROUND OF THE INVENTION
In the present invention, a titanium carbonitride layer (hereinafter referred to as l-TiCN) having a vertically grown crystal structure constituting a hard coating layer has excellent chipping resistance, and in particular, intermittent cutting such as steel and cast iron can be performed at high speed. Even when performed, it relates to a surface-coated cemented carbide cutting tool (hereinafter referred to as a coated carbide tool) that exhibits excellent cutting performance over a long period of time without occurrence of chipping (small chipping) on the cutting edge. is there.
[0002]
[Prior art]
Conventionally, in general, on the surface of a tungsten carbide base cemented carbide substrate (hereinafter referred to as a cemented carbide substrate),
(A) Titanium carbide (hereinafter referred to as TiC) layer, titanium nitride (hereinafter also referred to as TiN) layer, titanium carbonitride (hereinafter referred to as TiN) layer each having an average layer thickness and granular crystal structure of 0.1 to 5 μm. ) layer shown by TiCN, titanium oxide (hereinafter, Ti 2 O indicated by 3) layer, carbonation titanium (hereinafter, indicated by TiCO) layer, oxynitride of titanium (hereinafter, indicated by TiNO) layer, and titanium oxycarbonitride ( Hereinafter, a Ti compound layer composed of one or more of the layers (shown as TiCNO),
(B) an l-TiCN layer having an average layer thickness of 2 to 15 μm;
(C) an aluminum oxide (hereinafter referred to as Al 2 O 3 ) layer having an average layer thickness of 0.5 to 8 μm and a granular crystal structure;
Coated carbide tools made by chemical vapor deposition of a hard coating layer composed of 3 to 25 μm in total average layer thickness are known, and this coated carbide tool is used for continuous cutting and intermittent cutting of steel and cast iron. It is also known to be used.
It is also well known that generally Al 2 O 3 layers constituting the hard coating layer of the above-mentioned coated carbide tool are widely used in practical use, such as those having an α-type crystal structure and those having a κ-type crystal structure. Further, the l-TiCN layer is known, for example, from JP-A-6-8010 and JP-A-7-328808, and an organic carbonitride is used as a reaction gas in a normal chemical vapor deposition apparatus. It is formed by chemical vapor deposition at a medium temperature range of 700 to 950 ° C. using a mixed gas.
[0003]
[Problems to be solved by the invention]
On the other hand, in recent years, there is a strong demand for labor saving and energy saving and further cost reduction for cutting, and with this, cutting tends to be performed at high speed. Since the 1-TiCN layer constituting the coating layer has relatively good toughness, the hard coating layer also has good toughness, and in continuous cutting and intermittent cutting under normal conditions, the cutting edge However, when cutting intermittently at high speed, the cutting conditions become even more severe, and it does not have sufficient toughness. It is inevitable that chipping occurs on the cutting edge, and the service life is reached in a relatively short time.
[0004]
[Means for Solving the Problems]
Therefore, the present inventors focused on the l-TiCN layer constituting the hard coating layer of the above conventional coated carbide tool from the above viewpoint, and as a result of conducting research to improve the toughness of this,
At the time of vapor deposition formation of the 1-TiCN layer, a reaction gas composed of components of TiCl 4 , N 2 , CH 3 CN and H 2 is formed on the upper surface portion, and TiCl 4 , N 2 , CH 4 , CH 3 CN is formed on the lower surface portion. , And H 2 , and N 2 and CH 3 CN in the reaction gas are formed in the upper surface portion, and N 2 , CH 4 and CH 3 CN in the reaction gas are formed in the lower surface portion. By changing stepwise over time or stepwise, the l-TiCN layer is given a concentration gradient in which the C component decreases and the N component increases along the layer thickness from the lower surface to the upper surface. In this concentration gradient, when the upper surface portion and the lower surface portion are expressed by a composition formula: TiC 1-x N x ,
The upper surface portion has x: 0.45 to 0.60,
The lower surface portion has x: 0.05 to 0.30 ,
(In this case, the change in the concentration of C and N from the lower surface portion to the upper surface portion is a stepless change or a step change), the resulting l-TiCN layer (hereinafter referred to as a concentration gradient l-TiCN layer). Is superior in toughness as compared with a uniform conventional l-TiCN layer having no concentration change in C and N from the lower surface portion to the upper surface portion, and thus the concentration gradient l-TiCN layer. The coated carbide tool that constitutes the hard coating layer has the toughness of the interrupted cutting performed at high speed because the toughness of the hard coating layer itself is further improved by the concentration gradient l-TiCN layer. However, we have obtained research results that the cutting edge will show excellent cutting performance without chipping.
[0005]
This invention was made based on the above research results, and on the surface of the carbide substrate,
(A) One of a TiC layer, a TiN layer, a TiCN layer, a Ti 2 O 3 layer, a TiCO layer, a TiNO layer, and a TiCNO layer, all having an average layer thickness of 0.1 to 5 μm and a granular crystal structure Or a Ti compound layer comprising two or more types,
(B) an l-TiCN layer having an average layer thickness of 2 to 15 μm;
(C) an Al 2 O 3 layer having an average layer thickness of 0.5 to 8 μm and a granular crystal structure;
In in coated cemented carbide formed by chemical vapor deposition of a hard coating layer composed of a total average layer thickness of 3～25Myuemu,
L-TiCN layer constituting the hard coating layer,
TiCl on the lower surface portion forming 4, N 2, CH 4, CH 3 CN, and the reaction gas consisting of components of H 2, TiCl 4 on the upper surface portion forming, N 2, CH 3 CN, and components of the H 2 using a reaction gas composed of, and the the lower surface portion forming the reaction of N 2 gas, CH 4, and CH 3 the content of CN, also above the upper surface portion forming N 2 and in the reaction gas By changing the content ratio of CH 3 CN steplessly or stepwise over time, the C component decreases along the layer thickness from the lower surface portion toward the upper surface portion, the N component increases, and the C and N When the upper surface portion and the lower surface portion thereof are expressed by the composition formula: TiC 1-x N x , the atomic ratio is expressed in a stepless or stepwise concentration gradient.
The upper surface portion has x: 0.45 to 0.60,
The lower surface portion has x: 0.05 to 0.30 ,
It is characterized by a coated cemented carbide tool that is composed of an l-TiCN layer that satisfies the above requirements and exhibits excellent chipping resistance in a high-speed intermittent cutting process.
[0006]
In the composition formula of the concentration gradient l-TiCN layer constituting the hard coating layer of the coated carbide tool of the present invention: TiC 1-x N x , the x value of the upper surface portion is preferably 0.45 to 0.60, preferably Is set to 0.50 to 0.55, and the x value of the lower surface portion is set to 0.05 to 0.30 because the x value of the upper surface portion is less than 0.45 or the x value of the lower surface portion is 0.30. Over the thickness range, the concentration gradient of C and N in the layer thickness direction becomes small, and the hard coating layer does not have a sufficient toughness improving effect to exhibit the desired chipping resistance in high-speed intermittent cutting. Even if the x value of the portion exceeds 0.60, a further improvement effect does not appear due to chipping resistance in high-speed intermittent cutting, and when the x value of the lower surface portion is less than 0.05, a homogeneous vertically grown crystal structure This is based on the reason that the stable formation of is impaired.
[0007]
Similarly, each of the Ti compound layers constituting the hard coating layer has an effect of improving the interlayer adhesion between the constituent layers. Therefore, when the average layer thickness is less than 0.1 μm, the desired excellent interlayer adhesion is achieved. On the other hand, if the average layer thickness exceeds 5 μm, the progress of wear of the hard coating layer is promoted, so the average layer thickness was set to 0.1 to 5 μm.
Similarly, the Al 2 O 3 layer has an effect of improving the wear resistance of the hard coating layer, but if the average layer thickness is less than 0.5 μm, the desired excellent wear resistance cannot be ensured, On the other hand, if the average layer thickness exceeds 8 μm, chipping is likely to occur at the cutting edge, so the average layer thickness was set to 0.5 to 8 μm.
Furthermore, the concentration gradient l-TiCN layer has the effect of improving the chipping resistance of the hard coating layer by high-speed intermittent cutting as described above, but if the average layer thickness is less than 2 μm, the desired improvement effect on the chipping resistance is achieved. On the other hand, when the average layer thickness exceeds 15 μm, the wear resistance rapidly decreases, so the average layer thickness was set to 2 to 15 μm.
Also, the reason that the overall average layer thickness of the hard coating layer is 3 to 25 μm is that if the average layer thickness is less than 3 μm, the desired wear resistance cannot be ensured, while the average layer thickness exceeds 25 μm. This is because chipping and chipping are likely to occur in the cutting edge.
[0008]
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, fine WC powder having an average particle diameter of 1.5 μm, medium WC powder of 3.0 μm and 1.2 μm of (Ti, W) CN (in weight ratio, the same shall apply hereinafter, TiC / TiN / WC = 24/20/56) powder, 1.3 μm (Ta, Nb) C (TaC / NbC = 90/10) powder, 1 μm Cr 3 C 2 powder, 1.2 μm VC powder, and 1 Prepare 2 .mu.m Co powder, blend these raw material powders into the composition shown in Table 1, wet mix with a ball mill for 72 hours, and dry. Then, this mixed powder is compacted into a shape conforming to ISO standard CNMG120408. body by press molding, carbide substrate A~F by this green compact in a vacuum atmosphere of 10 -3 torr, vacuum sintering under conditions of 1 hour hold time at a predetermined temperature in the range of from 1,400 to 1,460 ° C. Were manufactured respectively.
[0009]
Then, with the surface of these carbide substrates A to F being subjected to honing processing, a normal chemical vapor deposition apparatus was used, and Tables 2 and 3 (all constituent layers of the hard coating layer shown in Table 2) Under the conditions shown in (1) the composition has a uniform composition with no change in concentration from the lower surface to the upper surface of the layer, and all except the 1-TiCN layer have a granular crystal structure) The coated carbide tools 1-8 of the present invention and the conventional coated carbide tools 1-8 were produced by forming a hard coating layer having the composition and target layer thickness (flank of the cutting edge) shown in Tables 4 and 5, respectively. .
In Table 4, for example, “l-TiCN-car [2 stages] l-TiCN-3 (4.0)” of the coated carbide tool 3 of the present invention is “lower surface part / l-TiCN-carriage” in Table 3. (target x value: 0.30) "top surface · l-TiCN-3 (a target value x 0.55) from the reaction gas composition" of CH 3 CN in the reaction gas to the reaction gas composition "or CH 3, the content of the CN and CH 4 and over time by a two-step change is indicative of the case of forming a concentration gradient l-TiCN layer at the target layer thickness of 4.0 .mu.m, likewise of the present invention coated carbide tools 7 '"l-TiCN-o [continuous] l-TiCN-4 (6.6)" is derived from the reaction gas composition of "lower surface part l-TiCN-o (target x value: 0.25)". -TiCN-4 (target x value: 0.60) "CH 3 CN in the reaction gas up to the reaction gas composition, or CH 3 This shows a case where a concentration gradient l-TiCN layer is formed with a target layer thickness of 6.6 μm by changing the content ratio of CN and CH 4 steplessly over time.
As a result, Auger spectroscopic analysis of 0.2 μm inner side from each surface is carried out about x value of the upper surface part of a concentration gradient l-TiCN layer which comprises the hard coating layer of this invention coated carbide tools 1-8 , and a lower surface part. As a result of measurement using a vessel, the x value was substantially the same as the target x value shown in Table 3. In addition, the constituent layers constituting the hard coating layer also showed an average layer thickness substantially the same as the target layer thickness.
[0010]
Next, about the said invention coated carbide tools 1-8 and the conventional coated carbide tools 1-8 ,
Work material: SCM440 lengthwise equal 4 round bars with longitudinal grooves,
Cutting speed: 350 m / min,
Incision: 1.5mm,
Feed: 0.25mm / rev,
Cutting time: 10 minutes,
Dry high-speed intermittent cutting test of alloy steel under the conditions of
Work material: Round bars with four longitudinal grooves at equal intervals in the length direction of FCD450,
Cutting speed: 350 m / min,
Incision: 1.5mm,
Feed: 0.32mm / rev,
Cutting time: 10 minutes,
A dry high-speed intermittent cutting test was performed on spheroidal graphite cast iron under the conditions described above, and the maximum flank wear width of the cutting edge was measured in all cutting tests. The measurement results are shown in Table 6.
[0011]
[Table 1]
[Table 2]
[Table 3]
[Table 4]
[Table 5]
[Table 6]
【The invention's effect】
From the results shown in Tables 4 to 6, the coated carbide tools 1 to 8 of the present invention in which the concentration gradient l-TiCN layer is present in the hard coating layer are all excellent in the hard coating layer by the concentration gradient l-TiCN layer. Since it has excellent toughness, it exhibits excellent cutting performance without chipping on the cutting edge even when intermittent cutting of steel or cast iron is performed at high speed. -In the conventional coated carbide tools 1 to 8 having no concentration gradient in C and N of the TiCN layer, the above-mentioned high-speed intermittent cutting causes chipping on the cutting edge due to insufficient toughness of the hard coating layer, and it takes a relatively short time. It is clear that the service life is reached.
As described above, the coated cemented carbide tool of the present invention has excellent chipping resistance due to the hard coating layer that constitutes the coated hard tool, so that of course continuous cutting and intermittent cutting under normal conditions such as steel and cast iron, for example. In particular, even when intermittent cutting is performed at high speed, it exhibits excellent cutting performance over a long period of time, so it can fully satisfy the labor saving and energy saving of cutting work, and further cost reduction It is.
Claims (1)
（ａ）いずれも０．１〜５μｍの平均層厚および粒状結晶組織を有する、炭化チタン層、窒化チタン層、炭窒化チタン層、酸化チタン層、炭酸化チタン層、窒酸化チタン層、および炭窒酸化チタン層のうちの１種または２種以上からなるＴｉ化合物層、
（ｂ）２〜１５μｍの平均層厚および縦長成長結晶組織を有する炭窒化チタン層、
（ｃ）０．５〜８μｍの平均層厚および粒状結晶組織を有する酸化アルミニウム層、
以上（ａ）〜（ｃ）で構成された硬質被覆層を３〜２５μｍの全体平均層厚で化学蒸着してなる表面被覆超硬合金製切削工具において、
上記硬質被覆層を構成する縦長成長結晶組織の炭窒化チタン層を、
下面部形成にはＴｉＣｌ ４ ，Ｎ ２ ，ＣＨ ４ ，ＣＨ ３ ＣＮ，およびＨ ２ の構成成分からなる反応ガス、上面部形成にはＴｉＣｌ ４ ，Ｎ ２ ，ＣＨ ３ ＣＮ，およびＨ ２ の構成成分からなる反応ガスを用い、かつ、前記下面部形成には前記反応ガス中のＮ ２ ，ＣＨ ４ ，およびＣＨ ３ ＣＮの含有割合を、また前記上面部形成には前記反応ガス中のＮ ２ およびＣＨ ３ ＣＮの含有割合を経時的に無段階あるいは段階的に変化させて、下面部から上面部に向かって層厚にそってＣ成分が低く、Ｎ成分が高くなり、かつ、前記ＣおよびＮの濃度が無段階変化または段階変化する濃度勾配を具備せしめると共に、前記上面部および下面部を組成式：ＴｉＣ１−ＸＮＸで現した場合、原子比で、
上記上面部は、Ｘ：０．４５〜０．６０、
上記下面部は、Ｘ：０．０５〜０．３０、
を満足する縦長成長結晶組織の炭窒化チタン層で構成したことを特徴とする高速断続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表面被覆超硬合金製切削工具。On the surface of the tungsten carbide base cemented carbide substrate,
(A) Titanium carbide layer, titanium nitride layer, titanium carbonitride layer, titanium oxide layer, titanium carbonate layer, titanium oxynitride layer, and charcoal, all having an average layer thickness and granular crystal structure of 0.1 to 5 μm A Ti compound layer comprising one or more of the titanium nitride oxide layers,
(B) a titanium carbonitride layer having an average layer thickness of 2 to 15 μm and a vertically grown crystal structure,
(C) an aluminum oxide layer having an average layer thickness of 0.5 to 8 μm and a granular crystal structure,
In the surface-coated cemented carbide cutting tool formed by chemical vapor deposition of the hard coating layer composed of the above (a) to (c) with an overall average layer thickness of 3 to 25 μm,
A vertically-grown titanium carbonitride layer constituting the hard coating layer,
TiCl on the lower surface portion forming 4, N 2, CH 4, CH 3 CN, and the reaction gas consisting of components of H 2, TiCl 4 on the upper surface portion forming, N 2, CH 3 CN, and components of the H 2 using a reaction gas composed of, and the the lower surface portion forming the reaction of N 2 gas, CH 4, and CH 3 the content of CN, also above the upper surface portion forming N 2 and in the reaction gas By changing the content ratio of CH 3 CN steplessly or stepwise over time, the C component decreases along the layer thickness from the lower surface portion toward the upper surface portion, the N component increases, and the C and N In the case where the upper surface portion and the lower surface portion are expressed by the composition formula: TiC 1-X N X , the atomic ratio is expressed in a stepless or stepwise concentration gradient.
The upper surface portion has X: 0.45 to 0.60,
The lower surface portion has X: 0.05 to 0.30 ,
A surface-coated cemented carbide cutting tool that exhibits excellent chipping resistance in high-speed intermittent cutting, characterized by comprising a vertically grown crystallographic titanium carbonitride layer that satisfies the above requirements.
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| JP4518260B2 (en) * | 2005-01-21 | 2010-08-04 | 三菱マテリアル株式会社 | Surface-coated cermet cutting tool whose hard coating layer exhibits excellent chipping resistance in high-speed intermittent cutting |
| JP5061392B2 (en) * | 2008-07-30 | 2012-10-31 | 住友電工ハードメタル株式会社 | Surface coated cutting tool |
| US9228258B2 (en) | 2011-03-31 | 2016-01-05 | Hitachi Tool Engineering, Ltd. | Hard-coated member and its production method, and indexable rotary tool comprising it |
| EP2604720A1 (en) * | 2011-12-14 | 2013-06-19 | Sandvik Intellectual Property Ab | Coated cutting tool and method of manufacturing the same |
| KR101906650B1 (en) * | 2012-04-19 | 2018-10-10 | 스미또모 덴꼬오 하드메탈 가부시끼가이샤 | Surface-coated cutting tool |
| KR102056206B1 (en) * | 2012-10-01 | 2019-12-16 | 미츠비시 히타치 쓰루 가부시키가이샤 | Hard film coating tool and method for manufacturing said tool |
| JP6614447B2 (en) * | 2016-03-28 | 2019-12-04 | 三菱マテリアル株式会社 | Surface coated cutting tool with excellent chipping and peeling resistance with excellent hard coating layer |
| JP6677876B2 (en) * | 2016-08-09 | 2020-04-08 | 三菱マテリアル株式会社 | Surface coated cutting tool with excellent welding chipping and peeling resistance |
| JP6916472B2 (en) * | 2019-08-30 | 2021-08-11 | 株式会社タンガロイ | Cover cutting tool |
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