JP4029529B2 - Surface coated tungsten carbide based cemented carbide cutting tool with excellent chipping resistance with hard coating layer in intermittent heavy cutting - Google Patents
Surface coated tungsten carbide based cemented carbide cutting tool with excellent chipping resistance with hard coating layer in intermittent heavy cutting Download PDFInfo
- Publication number
- JP4029529B2 JP4029529B2 JP27233799A JP27233799A JP4029529B2 JP 4029529 B2 JP4029529 B2 JP 4029529B2 JP 27233799 A JP27233799 A JP 27233799A JP 27233799 A JP27233799 A JP 27233799A JP 4029529 B2 JP4029529 B2 JP 4029529B2
- Authority
- JP
- Japan
- Prior art keywords
- layer
- cutting
- layer thickness
- average
- hard coating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Landscapes
- Cutting Tools, Boring Holders, And Turrets (AREA)
- Chemical Vapour Deposition (AREA)
Description
【０００１】
【発明の属する技術分野】
この発明は、特に断続切削を高送りおよび高切り込みなどの重切削条件で行った場合に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炭化タングステン基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、炭酸化チタン（以下、ＴｉＣＯ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の平均層厚および縦長成長結晶組織を有する炭窒化チタン（以下、ｌ−ＴｉＣＮで示す）層と、
（ｃ） ０．５〜１０μｍ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５〜２５μｍ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、近年の切削装置のＦＡ化はめざましく、また切削加工に対する省力化および省エネ化、さらに低コスト化の要求も強く、これに伴い、切削工具には、通常の条件での連続切削および断続切削は勿論のこと、切削条件としてはきわめて過酷な条件となる断続高送りや断続高切り込みなどの断続重切削条件での切削も行うことのできる汎用性が求められているが、上記の従来被覆超硬工具においては、特にこれを断続切削を高送りおよび高切り込みなどの重切削条件で行うのに用いると、硬質被覆層にチッピング（微小欠け）が発生し易く、これが原因で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における硬質被覆層の耐チッピング性向上を図るべく研究を行った結果、
（ａ）上記の従来被覆超硬工具の硬質被覆層においては、これを化学蒸着法にて形成した場合、いずれの構成層にもその結晶組織が粒状結晶であっても、また縦長成長結晶であっても３０〜７０ｋｇｆ／ｍｍの残留引張応力が存在し、これが高衝撃のかかる断続重切削ではチッピング発生の原因となること。
【０００５】
（ｂ）上記の通り被覆超硬工具の硬質被覆層を構成するＴｉ化合物層およびＡｌ2 Ｏ3 層、さらにｌ−ＴｉＣＮ層を化学蒸着法により形成した場合、いずれも引張応力が残留し、これを圧縮応力が残留するように形成することはできないが、前記ｌ−ＴｉＣＮ層においては、引張応力が残留したｌ−ＴｉＣＮ層（下方部分層）を形成した後に、蒸着条件を変えることにより前記下方部分層のもつ縦長成長結晶組織を損なわずに、すなわち前記下方部分層のもつ縦長成長結晶組織と連続した縦長成長結晶組織のままで、５〜２０ｋｇｆ／ｍｍの圧縮応力が残留したｌ−ＴｉＣＮ層（上方部分層）を形成することができること。
【０００６】
（ｃ）上記の５〜２０ｋｇｆ／ｍｍの圧縮応力が残留したｌ−ＴｉＣＮ層（上方部分層）は、まず通常の条件、すなわち、
反応ガス組成（容量％で、以下同じ）−ＴｉＣｌ4 ：１〜３％、Ｎ2：２０〜４０％、ＣＨ3ＣＮ：０．１〜１％、Ｈ2 ：残り、
雰囲気温度：８００〜９２０℃、
雰囲気圧力：５０〜１５０Ｔｏｒｒ、
の条件で３０〜７０ｋｇｆ／ｍｍの残留引張応力が存在するｌ−ＴｉＣＮ層（下方部分層）を所定層厚になるまで化学蒸着形成した後で、蒸着条件を、
反応ガス組成−ＴｉＣｌ4 ：０．１〜１％、Ｎ2：３０〜５０％、ＣＨ3ＣＮ：０．１〜１％、Ｈ2 ：残り、
雰囲気温度：９４０〜１０００℃、
雰囲気圧力：５０〜２００Ｔｏｒｒ、
に変え、所定時間化学蒸着を行うことにより形成できること。
【０００７】
（ｄ）また、上記の被覆超硬工具の硬質被覆層を構成するＴｉ化合物層のうちのＴｉＣ層に関しても、粒状結晶組織を有するＴｉＣ層は、
反応ガス組成−ＴｉＣｌ4 ：１〜６％、ＣＨ4：２〜１０％、Ｈ2 ：残り、
雰囲気温度：９５０〜１０００℃、
雰囲気圧力：５０〜１５０Ｔｏｒｒ、
の条件で化学蒸着されているが、この化学蒸着条件に比して、反応ガスにおけるＴｉＣ形成成分の濃度を相対的に低くし、かつ反応雰囲気温度および反応雰囲気圧力を高くした条件、すなわち、
反応ガス組成−ＴｉＣｌ4 ：０．５〜２％、ＣＨ4：１〜３％、Ｈ2 ：残り、
雰囲気温度：９３０〜１０５０℃、
雰囲気圧力：４００〜６００Ｔｏｒｒ、
とした条件でＴｉＣ層の化学蒸着を行うと、上記のｌ-ＴｉＣＮ層と実質的に同じ破面組織および光学顕微鏡組織を有する縦長成長結晶組織のＴｉＣ層が形成されるようになること。
【０００８】
（ｅ）さらに、上記（ｄ）で形成された縦長成長結晶組織を有するＴｉＣ（以下、ｌ−ＴｉＣで示す）層にも、３０〜７０ｋｇｆ／ｍｍの残留引張応力が存在するが、上記（ｃ）で述べたｌ−ＴｉＣＮ層と同様に、まず上記の（ｄ）条件で３０〜７０ｋｇｆ／ｍｍの残留引張応力が存在するｌ−ＴｉＣ層（下方部分層）を所定層厚になるまで化学蒸着形成した後で、蒸着条件を、
反応ガス組成−ＴｉＣｌ4 ：０．５〜５％、ＣＨ4：１〜５％、Ｈ2 ：残り、
雰囲気温度：９５０〜１１５０℃、
雰囲気圧力：５０〜２００Ｔｏｒｒ、
に変え、所定時間化学蒸着を行うと、上記下方部分層のもつ縦長成長結晶組織を損なわずに、すなわち前記下方部分層のもつ縦長成長結晶組織と連続した縦長成長結晶組織のままで、１０〜３０ｋｇｆ／ｍｍの圧縮応力が残留したｌ−ＴｉＣ層（上方部分層）を形成することができること。
【０００９】
（ｆ）上記（ｃ）および（ｅ）に示される、いずれも下方部分に残留引張応力が存在し、上方部分に残留圧縮応力が存在した応力分布をもったｌ−ＴｉＣＮ層およびｌ−ＴｉＣ層を上記硬質被覆層の構成層として存在させると、この結果の被覆超硬工具は、断続切削を重切削条件で行う高衝撃付加切削に用いても、前記硬質被覆層がすぐれた耐チッピング性をもつようになることから、長期に亘ってすぐれた切削性能を発揮すること。
【００１０】
（ｇ）上記硬質被覆層を構成するｌ−ＴｉＣＮ層およびｌ−ＴｉＣ層での残留圧縮応力が存在する上方部分層は、いずれも後述する理由により前記ｌ−ＴｉＣＮ層およびｌ−ＴｉＣ層の平均層厚の２０〜４０％に相当する層厚をもつことが必要であること。
以上（ａ）〜（ｇ）に示される研究結果を得たのである。
【００１１】
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し、かつ残留引張応力が存在する、ＴｉＣ層、ＴｉＮ層、ＴｉＣＮ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の平均層厚を有し、残留圧縮応力が存在する上方部分層と残留引張応力が存在する下方部分層からなり、前記上方部分層と前記下方部分層は相互に連続した縦長成長結晶組織を有し、かつ前記上方部分層は、前記２〜１５μｍの平均層厚の２０〜４０％に相当する層厚を有するｌ−ＴｉＣＮ層と、
（ｃ） ２〜１５μｍの平均層厚を有し、残留圧縮応力が存在する上方部分層と残留引張応力が存在する下方部分層からなり、前記上方部分層と前記下方部分層は相互に連続した縦長成長結晶組織を有し、かつ前記上方部分層は、前記２〜１５μｍの平均層厚の２０〜４０％に相当する層厚を有するｌ−ＴｉＣ層と、
（ｄ） ０．５〜１０μｍの平均層厚および粒状結晶組織を有し、かつ残留引張応力が存在するＡｌ2 Ｏ3 層と、
で構成された硬質被覆層を５〜２５μｍの全体平均層厚で化学蒸着してなる、断続重切削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。
【００１２】
なお、この発明の被覆超硬工具の硬質被覆層を構成するｌ−ＴｉＣＮ層およびｌ−ＴｉＣ層の上方部分層の層厚については、両者の上方部分層のうちのいずれかの層厚でもその平均層厚の２０％未満になると、硬質被覆層における残留圧縮応力の残留引張応力に対する相対的割合が低くなるばかりでなく、硬質被覆層全体の残留応力分布のバランスがくずれ、これが原因で切刃にチッピングが発生し易くなり、一方いずれの層厚も前記ｌ−ＴｉＣＮ層およびｌ−ＴｉＣ層の平均層厚の４０％を越えると、縦長成長結晶組織に粒状結晶組織が混入し、縦長成長結晶組織によってもたらされるすぐれた靭性が損なわれるようになるという理由から、その平均層厚の２０〜４０％と定めたのである。
【００１３】
さらに、この発明の被覆超硬工具の硬質被覆層における構成層の平均層厚は以下の理由により定めたものである。
すなわち、Ｔｉ化合物層のそれぞれには、共通する性質として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いずれかでも５μｍ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０．１〜５μｍと定めた。
【００１４】
また、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１０μｍ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０．５〜１０μｍと定めた。
【００１５】
さらに、ｌ−ＴｉＣＮ層およびｌ−ＴｉＣ層には、上記の通り共に硬質被覆層に縦長成長結晶組織によるすぐれた靭性を付与し、かつそれぞれの上方部分層のもつ残留圧縮応力によって硬質被覆層における残留引張応力と残留圧縮応力の相対的応力分布を良好な状態に維持する作用があり、この結果硬質被覆層の耐チッピング性が向上するようになるが、その平均層厚がそれぞれ２μｍ未満では、前記作用に所望の効果が得られず、一方その平均層厚がいずれも１５μｍを越えると切刃に欠けやチッピングが発生し易くなることから、その平均層厚をいずれも２〜１５μｍと定めた。
また、硬質被覆層の全体平均層厚を５〜２５μｍとしたのは、その平均層厚が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。
【００１６】
【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の細粒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１．２μｍのＣｒ3Ｃ2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ＣＮＭＧ１２０４１２に則したスローアウエイチップ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〜Ｅをそれぞれ製造した。
さらに、上記超硬基体Ｅに対して、１００ｔｏｒｒのＣＨ4ガス雰囲気中、温度：１４００℃に１時間保持後、徐冷の条件で浸炭処理を施し、処理後超硬基体表面に付着するカーボンとＣｏを酸およびバレル研磨で除去することにより、表面から１１μｍの位置で最大Ｃｏ含有量：１５．９重量％、深さ：４２μｍのＣｏ富化帯域を基体表面部に形成した。
また、いずれも焼結したままで、上記超硬基体Ｃには表面部に表面から１７μｍの位置で最大Ｃｏ含有量：１０．０重量％、深さ：２３μｍのＣｏ富化帯域、上記超硬基体Ｄには表面部に表面から２２μｍの位置で最大Ｃｏ含有量：１４．５重量％、深さ：２９μｍのＣｏ富化帯域がそれぞれ形成されており、残りの超硬基体ＡおよびＢには前記Ｃｏ富化帯域の形成はなく、全体的に均一な組織をもつものであった。
さらに、表１には上記超硬基体Ａ〜Ｅの内部硬さ（ロックウエル硬さＡスケール）をそれぞれ示した。
【００１７】
ついで、これらの超硬基体Ａ〜Ｅを、所定の形状に加工およびホーニング加工した状態で、その表面に、通常の化学蒸着装置を用い、表２に示される条件にて、表３、４に示される目標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、硬質被覆層の構成層のうちのｌ−ＴｉＣＮ層およびｌ−ＴｉＣ層が残留圧縮応力が存在する上方部分層と残留引張応力が存在する下方部分層で構成された本発明被覆超硬工具１〜１０、並びに硬質被覆層の構成層のいずれにも残留引張応力が存在する従来被覆超硬工具１〜１０をそれぞれ製造した。
なお、この結果得られた各種の被覆超硬工具について、硬質被覆層の構成層の組成および平均層厚を電子プローブマイクロアナライザーおよび光学顕微鏡を用いて測定し、またそれぞれの構成層の残留応力をＸ線回折の測定結果に基づいて算出したところ、いずれも表３、４に示される目標組成および目標層厚と実質的に同じ組成および平均層厚を示し、かつ目標残留応力と実質的に同じ残留応力を示した。
【００１８】
つぎに、上記本発明被覆超硬工具１〜１０および従来被覆超硬工具１〜１０について、
被削材：ＪＩＳ・ＳＮＣＭ４３９の長さ方向等間隔４本縦溝入り丸棒、
切削速度：１８０ｍ／ｍｉｎ．、
切り込み：４ｍｍ、
送り：０．３ｍｍ／ｒｅｖ．、
切削時間：１０分、
の条件での合金鋼の乾式断続高切り込み切削試験、並びに、
被削材：ＪＩＳ・ＳＣＭ４４０の長さ方向等間隔４本縦溝入り丸棒、
切削速度：２００ｍ／ｍｉｎ．、
切り込み：２ｍｍ、
送り：０．６ｍｍ／ｒｅｖ．、
切削時間：１０分、
の条件での合金鋼の乾式断続高送り切削試験を行い、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５に示した。
【００１９】
【表１】
【表２】
【表３】
【表４】
【表５】
【発明の効果】
表２〜５に示される結果から、硬質被覆層中に構成層として存在するｌ−ＴｉＣＮ層およびｌ−ＴｉＣ層が残留圧縮応力を有する上方部分層と残留引張応力を有する下方部分層からなる本発明被覆超硬工具１〜１０は、いずれも前記硬質被覆層がすぐれた耐チッピング性を具備することから、特に断続切削を高送りや高切り込みなどの重切削条件で行っても切刃に欠けやチッピングの発生なく、すぐれた耐摩耗性を長期に亘って発揮するのに対して、硬質被覆層の構成層のいずれにも残留引張応力が存在する従来被覆超硬工具１〜１０においては、いずれも高衝撃の加わる断続重切削では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、例えば鋼や鋳鉄などの連続切削や断続切削は勿論のこと、高衝撃の加わる断続重切削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切削性能を示すものであるから、切削装置のＦＡ化、並びに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
The present invention provides a surface-coated tungsten carbide-based cemented carbide cutting tool (hereinafter referred to as a coating tool) that exhibits excellent chipping resistance when the hard coating layer is subjected to heavy cutting conditions such as high feed and high cutting. This is related to carbide tools.
[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. A Ti compound layer composed of one or more of a TiCN layer, a titanium carbonate (hereinafter referred to as TiCO) layer, and a titanium carbonitride oxide (hereinafter referred to as TiCNO) layer;
(B) a titanium carbonitride (hereinafter referred to as 1-TiCN) layer having an average layer thickness of 2 to 15 μm and a vertically grown crystal structure;
(C) an aluminum oxide (hereinafter referred to as Al 2 O 3 ) layer having an average layer thickness of 0.5 to 10 μm and a granular crystal structure;
A coated carbide tool formed by chemical vapor deposition of a hard coating layer composed of 5 to 25 μm in total average layer thickness is 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, the FA of cutting equipment has been remarkable in recent years, and there are strong demands for labor saving, energy saving, and cost reduction for cutting, and as a result, cutting tools have continuous cutting and intermittent cutting under normal conditions. Needless to say, versatility is required to perform cutting under intermittent heavy cutting conditions such as intermittent high feed and intermittent high cutting, which are extremely severe cutting conditions. In hard tools, especially when this is used to perform interrupted cutting under heavy cutting conditions such as high feed and high cutting, chipping (minute chipping) is likely to occur in the hard coating layer, and this causes relatively short time. At present, the service life is reached.
[0004]
[Means for Solving the Problems]
Therefore, the present inventors conducted research to improve the chipping resistance of the hard coating layer in the above conventional coated carbide tool from the above viewpoint,
(A) In the hard coating layer of the above-mentioned conventional coated carbide tool, when it is formed by chemical vapor deposition, any constituent layer may be a vertically grown crystal even if its crystal structure is a granular crystal. Even if there is a residual tensile stress of 30 to 70 kgf / mm, this may cause chipping in intermittent heavy cutting with high impact.
[0005]
(B) As described above, when the Ti compound layer, the Al 2 O 3 layer, and the l-TiCN layer constituting the hard coating layer of the coated carbide tool are formed by chemical vapor deposition, tensile stress remains in both cases. However, in the l-TiCN layer, after forming the l-TiCN layer (lower partial layer) in which the tensile stress remains, the lower layer can be formed by changing the deposition conditions. The 1-TiCN layer in which the compressive stress of 5 to 20 kgf / mm remains without damaging the vertically grown crystal structure of the partial layer, that is, the vertically grown crystal structure continuous with the vertically grown crystal structure of the lower partial layer. (Upper partial layer) can be formed.
[0006]
(C) The l-TiCN layer (upper partial layer) in which the compressive stress of 5 to 20 kgf / mm remains is first subjected to normal conditions, that is,
Reaction gas composition (in% by volume, hereinafter the same) -TiCl 4: 1~3%, N 2: 20~40%, CH 3 CN: 0.1~1%, H 2: remainder,
Atmospheric temperature: 800-920 ° C
Atmospheric pressure: 50 to 150 Torr,
After forming the l-TiCN layer (lower partial layer) having a residual tensile stress of 30 to 70 kgf / mm under the conditions of
The reaction gas composition -TiCl 4: 0.1~1%, N 2 : 30~50%, CH 3 CN: 0.1~1%, H 2: remainder,
Atmospheric temperature: 940 to 1000 ° C.
Atmospheric pressure: 50 to 200 Torr,
And can be formed by performing chemical vapor deposition for a predetermined time.
[0007]
(D) Moreover, regarding the TiC layer of the Ti compound layer constituting the hard coating layer of the above-described coated carbide tool, the TiC layer having a granular crystal structure is:
The reaction gas composition -TiCl 4: 1~6%, CH 4 : 2~10%, H 2: remainder,
Atmospheric temperature: 950 to 1000 ° C.
Atmospheric pressure: 50 to 150 Torr,
The chemical vapor deposition is performed under the conditions described above, but compared with the chemical vapor deposition conditions, the concentration of the TiC forming component in the reaction gas is relatively low, and the reaction atmosphere temperature and the reaction atmosphere pressure are increased, that is,
The reaction gas composition -TiCl 4: 0.5~2%, CH 4 : 1~3%, H 2: remainder,
Atmospheric temperature: 930-1050 ° C.
Atmospheric pressure: 400 to 600 Torr,
When the TiC layer is subjected to chemical vapor deposition under the conditions described above, a vertically grown crystal structure TiC layer having substantially the same fracture surface structure and optical microscope structure as the above-described l-TiCN layer is formed.
[0008]
(E) Further, a residual tensile stress of 30 to 70 kgf / mm is also present in the TiC (hereinafter referred to as 1-TiC) layer having the vertically grown crystal structure formed in (d) above. In the same manner as the l-TiCN layer described in (1), first, chemical vapor deposition of the l-TiC layer (lower partial layer) having a residual tensile stress of 30 to 70 kgf / mm under the condition (d) described above until a predetermined layer thickness is achieved. After forming, the deposition conditions are
The reaction gas composition -TiCl 4: 0.5~5%, CH 4 : 1~5%, H 2: remainder,
Atmosphere temperature: 950-1150 ° C.
Atmospheric pressure: 50 to 200 Torr,
If the chemical vapor deposition is performed for a predetermined time, the vertically grown crystal structure of the lower partial layer is not impaired, that is, the vertically grown crystal structure continuous with the vertically grown crystal structure of the lower partial layer is maintained. An l-TiC layer (upper partial layer) in which a compressive stress of 30 kgf / mm remains can be formed.
[0009]
(F) As shown in the above (c) and (e), the l-TiCN layer and the l-TiC layer each having a stress distribution in which residual tensile stress exists in the lower part and residual compressive stress exists in the upper part Is present as a constituent layer of the hard coating layer, the resulting coated carbide tool has excellent chipping resistance even when used for high impact applied cutting in which intermittent cutting is performed under heavy cutting conditions. Demonstrate excellent cutting performance over a long period of time.
[0010]
(G) The upper partial layer in which the residual compressive stress in the l-TiCN layer and the l-TiC layer constituting the hard coating layer is present is an average of the l-TiCN layer and the l-TiC layer for the reason described later. It is necessary to have a layer thickness corresponding to 20 to 40% of the layer thickness.
The research results shown in (a) to (g) above were obtained.
[0011]
This invention was made based on the above research results,
On the surface of the carbide substrate,
(A) Of the TiC layer, TiN layer, TiCN layer, TiCO layer, TiNO layer, and TiCNO layer, all of which have an average layer thickness and granular crystal structure of 0.1 to 5 μm, and a residual tensile stress exists A Ti compound layer comprising one or more of the following:
(B) It has an average layer thickness of 2 to 15 μm, and consists of an upper partial layer in which residual compressive stress exists and a lower partial layer in which residual tensile stress exists, and the upper partial layer and the lower partial layer are continuous with each other An l-TiCN layer having a vertically grown crystal structure and the upper partial layer having a layer thickness corresponding to 20 to 40% of the average layer thickness of 2 to 15 μm;
(C) It has an average layer thickness of 2 to 15 μm, and consists of an upper partial layer in which residual compressive stress exists and a lower partial layer in which residual tensile stress exists, and the upper partial layer and the lower partial layer are continuous with each other An l-TiC layer having a vertically grown crystal structure and the upper partial layer having a layer thickness corresponding to 20 to 40% of the average layer thickness of 2 to 15 μm;
(D) an Al 2 O 3 layer having an average layer thickness of 0.5 to 10 μm and a granular crystal structure and having residual tensile stress;
It is characterized by a coated carbide tool that exhibits excellent chipping resistance by intermittent heavy cutting, which is formed by chemical vapor deposition of a hard coating layer composed of 5 to 25 μm in total average layer thickness. .
[0012]
In addition, about the layer thickness of the upper part layer of the l-TiCN layer and the l-TiC layer constituting the hard coating layer of the coated carbide tool of the present invention, even the thickness of either of the upper part layers of the both is the same. When the average layer thickness is less than 20%, not only the relative ratio of the residual compressive stress to the residual tensile stress in the hard coating layer is lowered, but also the balance of the residual stress distribution of the entire hard coating layer is lost, which causes the cutting edge. On the other hand, if the layer thickness exceeds 40% of the average layer thickness of the l-TiCN layer and the l-TiC layer, a granular crystal structure is mixed in the vertically grown crystal structure, and the vertically grown crystal It was determined to be 20-40% of the average layer thickness because the superior toughness provided by the tissue would be compromised.
[0013]
Furthermore, the average layer thickness of the constituent layers in the hard coating layer of the coated carbide tool of the present invention is determined for the following reason.
That is, each of the Ti compound layers has a common property 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 ensured. On the other hand, if any of the average layer thicknesses exceeds 5 μm, chipping is likely to occur at the cutting edge. Therefore, the average layer thickness was set to 0.1 to 5 μm.
[0014]
In addition, the Al 2 O 3 layer has the 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 10 μm, chipping tends to occur at the cutting edge, so the average layer thickness was set to 0.5 to 10 μm.
[0015]
Further, the l-TiCN layer and the l-TiC layer both impart excellent toughness due to the vertically grown crystal structure to the hard coating layer as described above, and in the hard coating layer by the residual compressive stress of each upper partial layer. It has the effect of maintaining the relative stress distribution of the residual tensile stress and the residual compressive stress in a good state. As a result, the chipping resistance of the hard coating layer is improved, but when the average layer thickness is less than 2 μm, The desired effect cannot be obtained in the above action, and on the other hand, if the average layer thickness exceeds 15 μm, chipping and chipping are likely to occur in the cutting edge. Therefore, the average layer thickness is set to 2 to 15 μm. .
Also, the reason that the overall average layer thickness of the hard coating layer is 5 to 25 μm is that when the average layer thickness is less than 5 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.
[0016]
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 powder, average particle size: 1.5 μm fine WC powder, 3.0 μm medium WC powder, 1.2 μm (Ti, W) CN (weight ratio, the same below, TiC / TiN / WC) = 24/20/56) powder, 1.3 μm (Ta, Nb) C (TaC / NbC = 90/10) powder, 1.2 μm Cr 3 C 2 powder, and 1.2 μm Co powder These raw material powders are blended into the composition shown in Table 1, wet mixed by a ball mill for 72 hours, dried, and then the mixed powder is formed into a throwaway tip shaped green compact in accordance with ISO standard CNMG120212. Cemented carbide substrates A to E are respectively formed by press molding and vacuum sintering the compact in a vacuum atmosphere of 10 −3 torr at a predetermined temperature within the range of 1400 to 1460 ° C. for 1 hour. Manufactured.
Further, the carbide substrate E was subjected to a carburizing process under a slow cooling condition after being held at a temperature of 1400 ° C. for 1 hour in a CH 4 gas atmosphere of 100 torr. Was removed by acid and barrel polishing to form a Co-enriched zone having a maximum Co content of 15.9 wt% and a depth of 42 μm on the surface of the substrate at a position of 11 μm from the surface.
In addition, in the above-mentioned cemented carbide substrate C, the Co-enriched zone having a maximum Co content of 10.0% by weight and a depth of 23 μm at a position 17 μm from the surface at the surface portion, In the substrate D, a Co-enriched zone having a maximum Co content of 14.5% by weight and a depth of 29 μm is formed on the surface portion at a position of 22 μm from the surface, respectively. The Co-enriched zone was not formed, and the entire structure was uniform.
Further, Table 1 shows the internal hardness (Rockwell hardness A scale) of the above-mentioned carbide substrates A to E, respectively.
[0017]
Then, these carbide substrates A to E are processed and honed into a predetermined shape, and the surface thereof is subjected to Tables 3 and 4 under the conditions shown in Table 2 using a normal chemical vapor deposition apparatus. By forming a hard coating layer having the indicated target composition and target layer thickness (flank of the cutting edge), the residual compressive stress exists in the l-TiCN layer and the l-TiC layer of the constituent layers of the hard coating layer. Conventional coated cemented carbide tool 1 in which residual tensile stress exists in any of the constituent layers of the present invention coated carbide tools 1 to 10 composed of an upper partial layer and a lower partial layer in which residual tensile stress exists, and a hard coated layer To 10 were produced.
For the various coated carbide tools obtained as a result, the composition and average layer thickness of the constituent layers of the hard coating layer were measured using an electron probe microanalyzer and an optical microscope, and the residual stress of each constituent layer was measured. When calculated based on the measurement results of X-ray diffraction, both showed substantially the same composition and average layer thickness as the target composition and target layer thickness shown in Tables 3 and 4, and substantially the same as the target residual stress. Residual stress was shown.
[0018]
Next, for the present invention coated carbide tools 1-10 and conventional coated carbide tools 1-10,
Work material: JIS / SNCM439 round direction bar with 4 equal intervals in the length direction,
Cutting speed: 180 m / min. ,
Incision: 4mm,
Feed: 0.3 mm / rev. ,
Cutting time: 10 minutes,
Dry intermittent high cutting test of alloy steel under the conditions of, and
Work material: JIS · SCM440 lengthwise equidistant 4 vertical grooved round bar,
Cutting speed: 200 m / min. ,
Cutting depth: 2mm,
Feed: 0.6 mm / rev. ,
Cutting time: 10 minutes,
The dry interrupted high feed cutting test was performed on the alloy steel under the above conditions, and the maximum flank wear width of the cutting edge was measured in any cutting test. The measurement results are shown in Table 5.
[0019]
[Table 1]
[Table 2]
[Table 3]
[Table 4]
[Table 5]
【The invention's effect】
From the results shown in Tables 2 to 5, the 1-TiCN layer and the 1-TiC layer existing as constituent layers in the hard coating layer are composed of an upper partial layer having residual compressive stress and a lower partial layer having residual tensile stress. Invented coated carbide tools 1 to 10 all have excellent chipping resistance due to the hard coating layer, so that even when interrupted cutting is performed under heavy cutting conditions such as high feed and high cutting, the cutting edge is chipped. In the conventional coated carbide tools 1 to 10 in which residual tensile stress exists in any of the constituent layers of the hard coating layer, while exhibiting excellent wear resistance over a long period of time without occurrence of chipping, In any case, it is clear that intermittent cutting with high impact causes chipping, which leads to a service life in a relatively short time.
As described above, the coated carbide tool of the present invention exhibits excellent chipping resistance not only for continuous cutting and intermittent cutting of, for example, steel and cast iron, but also for intermittent heavy cutting with high impact. Since it shows excellent cutting performance, it can sufficiently satisfy the FA of the cutting device, labor saving and energy saving of cutting, and cost reduction.
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し、かつ残留引張応力が存在する、炭化チタン層、窒化チタン層、炭窒化チタン層、炭酸化チタン層、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化合物層と、
（ｂ） ２〜１５μｍの平均層厚を有し、残留圧縮応力が存在する上方部分層と残留引張応力が存在する下方部分層からなり、前記上方部分層と前記下方部分層は相互に連続した縦長成長結晶組織を有し、かつ前記上方部分層は、前記２〜１５μｍの平均層厚の２０〜４０％に相当する層厚を有する炭窒化チタン層と、
（ｃ） ２〜１５μｍの平均層厚を有し、残留圧縮応力が存在する上方部分層と残留引張応力が存在する下方部分層からなり、前記上方部分層と前記下方部分層は相互に連続した縦長成長結晶組織を有し、かつ前記上方部分層は、前記２〜１５μｍの平均層厚の２０〜４０％に相当する層厚を有する炭化チタン層と、
（ｄ） ０．５〜１０μｍ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と、
で構成された硬質被覆層を５〜２５μｍの全体平均層厚で化学蒸着してなる、断続重切削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炭化タングステン基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 carbonate layer, and charcoal, each having an average layer thickness and granular crystal structure of 0.1 to 5 μm, and having residual tensile stress A Ti compound layer composed of one or more of the titanium nitride oxide layers;
(B) It has an average layer thickness of 2 to 15 μm, and consists of an upper partial layer in which residual compressive stress exists and a lower partial layer in which residual tensile stress exists, and the upper partial layer and the lower partial layer are continuous with each other A titanium carbonitride layer having a vertically elongated crystal structure and the upper partial layer having a layer thickness corresponding to 20 to 40% of the average layer thickness of 2 to 15 μm;
(C) It has an average layer thickness of 2 to 15 μm, and consists of an upper partial layer in which residual compressive stress exists and a lower partial layer in which residual tensile stress exists, and the upper partial layer and the lower partial layer are continuous with each other A titanium carbide layer having a vertically grown crystal structure and the upper partial layer having a layer thickness corresponding to 20 to 40% of the average layer thickness of 2 to 15 μm;
(D) an aluminum oxide layer having an average layer thickness of 0.5 to 10 μm and a granular crystal structure;
A surface-coated tungsten carbide-based cemented carbide cutting tool that exhibits excellent chipping resistance by intermittent heavy cutting, wherein the hard coating layer is formed by chemical vapor deposition with an overall average layer thickness of 5 to 25 μm. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27233799A JP4029529B2 (en) | 1999-07-23 | 1999-09-27 | Surface coated tungsten carbide based cemented carbide cutting tool with excellent chipping resistance with hard coating layer in intermittent heavy cutting |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20849799 | 1999-07-23 | ||
| JP11-208497 | 1999-07-23 | ||
| JP27233799A JP4029529B2 (en) | 1999-07-23 | 1999-09-27 | Surface coated tungsten carbide based cemented carbide cutting tool with excellent chipping resistance with hard coating layer in intermittent heavy cutting |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2001096404A JP2001096404A (en) | 2001-04-10 |
| JP4029529B2 true JP4029529B2 (en) | 2008-01-09 |
Family
ID=26516867
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP27233799A Expired - Lifetime JP4029529B2 (en) | 1999-07-23 | 1999-09-27 | Surface coated tungsten carbide based cemented carbide cutting tool with excellent chipping resistance with hard coating layer in intermittent heavy cutting |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4029529B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100389918C (en) * | 2003-07-15 | 2008-05-28 | 复旦大学 | Multicomponent composite coated cutting tool and its preparation method |
| SE528696C2 (en) * | 2005-02-25 | 2007-01-23 | Sandvik Intellectual Property | CVD-coated carbide, cermet or ceramic cutter and ways of manufacturing the same |
| SE529023C2 (en) * | 2005-06-17 | 2007-04-10 | Sandvik Intellectual Property | Coated carbide cutter |
| US8715838B2 (en) | 2010-11-10 | 2014-05-06 | Sumitomo Electric Hardmetal Corp. | Surface-coated cutting tool |
-
1999
- 1999-09-27 JP JP27233799A patent/JP4029529B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JP2001096404A (en) | 2001-04-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3052586B2 (en) | Surface-coated tungsten carbide based cemented carbide cutting tool with excellent chipping resistance | |
| JP2867803B2 (en) | Surface-coated tungsten carbide based cemented carbide cutting tool with excellent chipping resistance | |
| JP3887811B2 (en) | Cutting tool made of surface-coated tungsten carbide based cemented carbide with a hard coating layer that provides excellent wear resistance in high-speed cutting | |
| JP3972299B2 (en) | Surface coated cermet cutting tool with excellent chipping resistance in high speed heavy cutting | |
| JP3236899B2 (en) | Manufacturing method of surface coated tungsten carbide based cemented carbide cutting tool with excellent wear and fracture resistance | |
| JP4029529B2 (en) | Surface coated tungsten carbide based cemented carbide cutting tool with excellent chipping resistance with hard coating layer in intermittent heavy cutting | |
| JP3661503B2 (en) | Surface coated tungsten carbide based cemented carbide cutting tool with excellent chipping resistance with hard coating layer in intermittent heavy cutting | |
| JP3087504B2 (en) | Manufacturing method of surface-coated tungsten carbide based cemented carbide cutting tools with excellent wear and fracture resistance | |
| JPH08118105A (en) | Surface-coated cemented carbide alloy cutting tool with tungsten carbide group having hard coating layer excellent in interlayer adhesion | |
| JPH10204639A (en) | Cutting tool made of surface-coated cemented carbide in which hard coating layer has excellent chipping resistance | |
| JP3837959B2 (en) | Surface coated tungsten carbide based cemented carbide cutting tool with excellent wear resistance due to hard coating layer | |
| JP4210930B2 (en) | Surface-coated throw-away tip that exhibits excellent chipping resistance with a hard coating layer in high-speed intermittent cutting | |
| JPH1076406A (en) | Cemented carbide cutting tool covered with hard covering layer excellent in anti-chipping property | |
| JP2002239807A (en) | Surface-covered thermet made cutting tool hard covered layer of which has excellent thermal shock resistance | |
| JP2001322003A (en) | Surface coated tungsten carbide group cemented carbide cutting tool having physically depositing hard coating layer with excellent chipping resistance | |
| JP3887812B2 (en) | Surface coated tungsten carbide based cemented carbide cutting tool with excellent chipping resistance with hard coating layer in intermittent heavy cutting | |
| JP2001150206A (en) | Surface-coated tungsten carbide group sintered allow- made cutting tool which displays excellent defect resistance in interrupted double cutting | |
| JP3282600B2 (en) | Surface-coated cemented carbide cutting tool with a hard coating layer that exhibits excellent fracture resistance | |
| JP2000218409A (en) | Surface coated cemented carbide cutting tool having hard coated layer of good defect resistance | |
| JP2000158207A (en) | Surface-covering tungsten carbide group cemented carbide alloy cutting tool having its hard covering layer exhibit excellent wear resistance | |
| JP4210931B2 (en) | Surface-coated throw-away tip that exhibits excellent chipping resistance with a hard coating layer in high-speed intermittent cutting | |
| JP3119414B2 (en) | Surface coated tungsten carbide based cemented carbide cutting tool with excellent interlayer adhesion with hard coating layer | |
| JPH08187604A (en) | Cutting tool of surface coated tungsten carbide based cemented carbide with its hard coating layer having excellent inter-layer adhesion | |
| JPH081408A (en) | Cutting tool made of surface-covered tungsten carbide base cemented carbide having excellent in-layer adhesion of hard covered layer | |
| JPH1076405A (en) | Cemented carbide cutting tool covered with hard covering layer excellent in anti-chipping property |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20050324 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20061006 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20070925 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20071008 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 4029529 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20101026 Year of fee payment: 3 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20101026 Year of fee payment: 3 |
|
| S531 | Written request for registration of change of domicile |
Free format text: JAPANESE INTERMEDIATE CODE: R313531 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20101026 Year of fee payment: 3 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20111026 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20121026 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20131026 Year of fee payment: 6 |
|
| EXPY | Cancellation because of completion of term |