JP2017154200A - Surface-coated cutting tool - Google Patents
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Abstract
Description
この発明は、焼入れ鋼などの高硬度鋼の強断続切削加工において、硬質被覆層がすぐれた耐クラック性と耐摩耗性を発揮し、長期の使用にわたってすぐれた切削性能を発揮する表面被覆切削工具（以下、被覆工具という）に関するものである。 The present invention provides a surface-coated cutting tool that exhibits excellent cracking resistance and wear resistance due to its hard coating layer in hard interrupted cutting of hardened steel such as hardened steel, and excellent cutting performance over a long period of use. (Hereinafter referred to as a coated tool).
一般に、被覆工具として、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、前記被削材の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、前記被削材の面削加工や溝加工、肩加工などに用いられるエンドミル、前記被削材の歯形の歯切加工などに用いられるソリッドホブ、ピニオンカッタなどが知られている。
そして、被覆工具の切削性能改善を目的として、従来から、数多くの提案がなされている。
In general, as a coated tool, for throwing inserts that can be used detachably attached to the tip of a cutting tool for turning and planing of various materials such as steel and cast iron, and for drilling and cutting the work material Known drills and miniature drills, end mills used for chamfering and grooving, shoulder processing, etc. of the work material, solid hob, pinion cutter used for gear cutting of the tooth profile of the work material, etc. Yes.
Many proposals have been made for the purpose of improving the cutting performance of the coated tool.
例えば、特許文献１に示すように、炭化タングステン（以下、ＷＣで示す）基超硬合金、炭窒化チタン（以下、ＴｉＣＮで示す）基サーメット等の工具基体の表面に、Ｃｒ、Ａｌ及びＳｉを主成分とする金属成分と、Ｃ、Ｎ、Ｏ、Ｂから選択される少なくとも１種以上の元素とから構成される立方晶構造の硬質層を１層以上被覆することにより、耐欠損性、耐摩耗性を改善した被覆工具が提案されている。 For example, as shown in Patent Document 1, Cr, Al, and Si are formed on the surface of a tool base such as tungsten carbide (hereinafter referred to as WC) -based cemented carbide, titanium carbonitride (hereinafter referred to as TiCN) -based cermet. By covering one or more hard layers having a cubic structure composed of a metal component as a main component and at least one element selected from C, N, O, and B, chipping resistance, Coated tools with improved wear have been proposed.
また、特許文献２には、工具基体表面に硬質被覆層を被覆した被覆工具において、硬質膜の少なくとも１層は、（ＭａＬｂ）Ｘｃ（但し、ＭはＣｒ，Ａｌ，Ｔｉ，Ｈｆ，Ｖ，Ｚｒ，Ｔａ，Ｍｏ，Ｗ，Ｙの中から選ばれた少なくとも１種の金属元素を示し、ＬはＭｎ，Ｃｕ，Ｎｉ，Ｃｏ，Ｂ，Ｓｉ，Ｓの中から選ばれた少なくとも１種の添加元素を示し、ＸはＣ，Ｎ，Ｏの中から選ばれた少なくとも１種の非金属元素を示し、ａはＭとＬとの合計に対するＭの原子比を示し、ｂはＭとＬとの合計に対するＬの原子比を示し、ｃはＭとＬとの合計に対するＸの原子比を示す。また、ａ，ｂ，ｃは、それぞれ０．８５≦ａ≦０．９９、０．０１≦ｂ≦０．１５、ａ＋ｂ＝１、１．００＜ｃ≦１．２０を満足する。）とすることで、硬質膜の成分であるＣｕ，Ｓｉ等による結晶粒の微細化、結晶安定性により、高温硬さが高くなり、耐摩耗性が向上し、さらに、耐酸化性も向上すると記載されている。 In Patent Document 2, in a coated tool in which a hard coating layer is coated on the surface of a tool base, at least one layer of the hard film is (MaLb) Xc (where M is Cr, Al, Ti, Hf, V, Zr). , Ta, Mo, W, Y represents at least one metal element selected from L, and L represents at least one additive element selected from Mn, Cu, Ni, Co, B, Si, S X represents at least one nonmetallic element selected from C, N, and O, a represents the atomic ratio of M to the sum of M and L, and b represents the sum of M and L C represents the atomic ratio of X to the sum of M and L. Further, a, b, and c are 0.85 ≦ a ≦ 0.99 and 0.01 ≦ b ≦, respectively. 0.15, a + b = 1, and 1.00 <c ≦ 1.20). Cu, grain refining of Si, etc., by crystallization stability, increases the high-temperature hardness, improved abrasion resistance, further, have been described to improved oxidation resistance.
さらに、特許文献３には、工具基体表面に、ＣｒとＡｌの複合窒化物からなる硬質被覆層を物理蒸着してなる被覆工具において、硬質被覆層を、層厚方向にそって、Ａｌ最高含有点とＡｌ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、かつ前記両点間でＡｌ含有量が連続的に変化する成分濃度分布構造を有し、さらに、上記Ａｌ最高含有点が、組成式：（Ｃｒ１−ＸＡｌＸ）Ｎ（ただし、原子比で、Ｘは０．４０〜０．６０を示す）を満足し、また、上記Ａｌ最低含有点が、組成式：（Ｃｒ１−ＹＡｌＹ）Ｎ（ただし、原子比で、Ｙは０．０５〜０．３０を示す）を満足し、かつ、隣り合う上記Ａｌ最高含有点とＡｌ最低含有点の間隔が、０．０１〜０．１μｍである硬質被覆層とすることにより、重切削加工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と記載されている。 Furthermore, in Patent Document 3, in a coated tool formed by physically vapor-depositing a hard coating layer made of a composite nitride of Cr and Al on the surface of a tool base, the hard coating layer contains the highest Al along the layer thickness direction. Points and Al minimum content points are alternately present repeatedly at a predetermined interval, and the Al content is continuously varied between the two points, and the Al maximum content point is , Composition formula: (Cr 1-X Al X ) N (wherein X is 0.40 to 0.60 in atomic ratio), and the above-mentioned Al minimum content point is the composition formula: (Cr 1-Y Al Y ) N (wherein Y represents 0.05 to 0.30 in atomic ratio), and the distance between the adjacent Al highest content point and Al minimum content point adjacent to each other is 0. Hard coating under heavy cutting conditions by using a hard coating layer of 01-0.1 μm It is described that the layer exhibits excellent chipping resistance.
近年の切削加工装置の高性能化はめざましく、一方で切削加工に対する省力化および省エネ化、さらに低コスト化の要求は強く、これに伴い、切削加工はますます高速化・高能率化の傾向にあるが、上記従来の被覆工具においては、これを鋼や鋳鉄などの通常の切削条件での切削加工に用いた場合には、特段の問題は生じないが、これを、例えば、焼入れ鋼などの高硬度鋼の強断続切削加工のような、高熱発生を伴い、しかも、切刃に対して衝撃的・断続的な高負荷がかかる切削加工に用いた場合には、クラックの発生・伝播を抑制することができず、また、摩耗進行も促進されるため、比較的短時間で使用寿命に至るのが現状である。 In recent years, the performance of cutting machines has been dramatically improved, while there is a strong demand for labor saving, energy saving, and cost reduction for cutting, and as a result, cutting has become a trend toward higher speed and higher efficiency. However, in the above-mentioned conventional coated tool, when it is used for cutting under normal cutting conditions such as steel and cast iron, no particular problem arises. Suppresses the generation and propagation of cracks when used for cutting that involves high heat generation, such as hard interrupted cutting of high hardness steel, and that imposes an impact and intermittent high load on the cutting edge. In addition, since the wear progress is promoted, the service life is reached in a relatively short time.
例えば、特許文献１に示される従来被覆工具においては、硬質被覆層を構成する（Ａｌ，Ｃｒ，Ｓｉ）Ｎ層のＡｌ成分は高温硬さ、同Ｃｒ成分は高温靭性、高温強度を向上させると共に、ＡｌおよびＣｒが共存含有した状態で高温耐酸化性を向上させ、さらに同Ｓｉ成分は耐熱塑性変形性を向上させる作用があるが、高熱発生を伴い、しかも、切刃に対して衝撃的・断続的な高負荷がかかる切削条件においては、チッピング、欠損等の原因となるクラックの発生を避けることはできず、例えば、Ｃｒ含有割合を増加することにより高温靭性、高温強度の改善を図ろうとしても、相対的なＡｌ含有割合の減少によって、耐摩耗性が低下してしまうため、（Ａｌ，Ｃｒ，Ｓｉ）Ｎ層からなる硬質被覆層における耐クラック性と耐摩耗性の両立を図るには自ずから限界がある。
また、特許文献２に示される従来被覆工具においては、硬質被覆層成分としてＣｕを含有させ、結晶粒の微細化を図ることによって耐摩耗性を向上させることが提案されているが、耐摩耗性が向上する反面、靭性が低下することによってクラックの発生を抑制することができず、工具寿命は短命である。
さらに、特許文献３に示される従来被覆工具においては、硬質被覆層中に繰り返し成分濃度が変化する組成変調構造を形成し、高温硬さと耐熱性はＡｌ最高含有点（Ｃｒ最低含有点に相当）で担保し、一方、硬質被覆層の強度は、Ａｌ最高含有点（Ｃｒ最低含有点に相当）に隣接するＡｌ最低含有点（Ｃｒ最低含有点に相当）で確保することにより、耐クラック性と耐摩耗性を確保しているが、通常の鋼や合金鋼、鋳鉄の切削加工ではある程度の効果は得られるものの、高硬度鋼（例えば、ＨＲＣ６０以上）の切削加工においては、切れ刃に作用する衝撃的・断続的な高負荷により、耐クラック性、耐摩耗性が十分であるとはいえない。
For example, in the conventional coated tool disclosed in Patent Document 1, the Al component of the (Al, Cr, Si) N layer constituting the hard coating layer improves high-temperature hardness, and the Cr component improves high-temperature toughness and high-temperature strength. In the coexistence of Al and Cr, the high-temperature oxidation resistance is improved, and further, the Si component has the effect of improving the heat-resistant plastic deformation property. Under cutting conditions that require intermittent high loads, it is impossible to avoid the occurrence of cracks that cause chipping, chipping, etc. For example, increasing the Cr content will improve high temperature toughness and strength. However, since the wear resistance deteriorates due to the relative decrease in the Al content ratio, both the crack resistance and the wear resistance of the hard coating layer made of the (Al, Cr, Si) N layer are achieved. There is naturally a limit to.
Further, in the conventional coated tool shown in Patent Document 2, it has been proposed to improve the wear resistance by containing Cu as a hard coating layer component and making the crystal grains finer. However, since the toughness is reduced, the generation of cracks cannot be suppressed and the tool life is short.
Furthermore, in the conventional coated tool shown in Patent Document 3, a composition modulation structure in which the component concentration is repeatedly changed is formed in the hard coating layer, and the high temperature hardness and heat resistance are the highest Al content point (corresponding to the lowest Cr content point). On the other hand, by ensuring the strength of the hard coating layer at the Al minimum content point (corresponding to the Cr minimum content point) adjacent to the Al maximum content point (corresponding to the Cr minimum content point), Although wear resistance is ensured, some effects can be obtained by cutting ordinary steel, alloy steel, and cast iron, but it acts on the cutting edge in cutting hardened steel (for example, HRC 60 or more). It cannot be said that crack resistance and wear resistance are sufficient due to shocking and intermittent high loads.
そこで、本発明者等は、上述の観点から、焼入れ鋼などの高硬度鋼の強断続切削加工のような、高熱発生を伴い、しかも、切刃に対して衝撃的・断続的な高負荷が作用する切削加工条件下で、硬質被覆層がすぐれた耐クラック性と耐摩耗性を両立し得る被覆工具を開発すべく、硬質被覆層を構成する成分および層構造に着目し研究を行った結果、以下のような知見を得た。 In view of the above, the present inventors, from the above viewpoint, are accompanied by high heat generation, such as hard interrupted cutting of hardened steel such as hardened steel. Results of research focusing on the components and layer structures that make up the hard coating layer in order to develop a coated tool that has both excellent crack resistance and wear resistance under the working cutting conditions The following findings were obtained.
即ち、本発明者は、ＡｌとＣｒとＳｉの複合窒化物層からなる硬質被覆層の成分として、Ｃｕを含有させることによって、ＡｌとＣｒとＳｉとＣｕの複合窒化物（以下、「（Ａｌ，Ｃｒ，Ｓｉ，Ｃｕ）Ｎ」で示す場合がある）層を硬質被覆層のＢ層として形成し、該Ｂ層によって結晶粒微細化による耐摩耗性向上と衝撃緩和性による耐クラック性向上を図り、さらに、工具基体と前記Ｂ層との間に、ＴｉとＡｌの複合窒化物（以下、「（Ｔｉ，Ａｌ）Ｎ」で示す場合がある）層をＡ層として介在形成することによって、工具基体および前記Ｂ層との密着強度を高め、前記Ａ層の具備する高温靭性、高温強度と相俟って、硬質被覆層全体としての耐クラック性、耐摩耗性を向上させることができることを見出した。 That is, the present inventor has incorporated Cu, as a component of the hard coating layer composed of a composite nitride layer of Al, Cr, and Si, so that a composite nitride of Al, Cr, Si, and Cu (hereinafter referred to as “(Al , Cr, Si, Cu) N ”) is formed as a B layer of a hard coating layer, and the B layer improves wear resistance by refining crystal grains and improves crack resistance by impact relaxation. Further, by interposing and forming a composite nitride of Ti and Al (hereinafter sometimes referred to as “(Ti, Al) N”) as an A layer between the tool base and the B layer, The adhesion strength between the tool substrate and the B layer can be increased, and combined with the high temperature toughness and high temperature strength of the A layer, the crack resistance and wear resistance of the entire hard coating layer can be improved. I found it.
また、本発明者らは、前記Ａ層およびＢ層をそれぞれ交互に多層に積層して硬質被覆層を交互積層構造として構成した場合には、耐剥離性にすぐれ、かつ、耐クラック性、耐摩耗性にすぐれた硬質被覆層を形成し得ることを見出した。 Further, the present inventors have excellent peeling resistance, crack resistance, anti-resistance when the A layer and the B layer are alternately laminated in multiple layers to form a hard coating layer as an alternately laminated structure. It has been found that a hard coating layer having excellent wear can be formed.
さらに、本発明者らは、前記Ｂ層について、層中のＣｒ成分濃度が層厚方向に沿って周期的に変化する組成変調構造をもった層として構成することによって、前記Ｂ層の靭性と耐摩耗性を一段と高め得ることを見出した。 Furthermore, the present inventors configured the B layer as a layer having a compositional modulation structure in which the Cr component concentration in the layer periodically changes along the layer thickness direction, thereby providing the toughness of the B layer. It has been found that the wear resistance can be further improved.
そして、前記硬質被覆層を備えた被覆工具は、高熱発生を伴い、しかも、切刃に対して衝撃的・断続的な高負荷が作用する焼入れ鋼などの高硬度鋼の強断続切削加工条件において、すぐれた耐クラック性、耐摩耗性を発揮することを見出したのである。 And the coated tool provided with the hard coating layer is accompanied by high heat generation, and in a severe interrupted cutting condition of hardened steel such as hardened steel in which impact and intermittent high load acts on the cutting edge. They have found that they exhibit excellent crack resistance and wear resistance.
この発明は、上記の知見に基づいてなされたものであって、
「立方晶窒化硼素焼結体からなる工具基体の表面に、０．５〜４．０μｍの合計平均層厚を有する硬質被覆層が設けられた表面被覆切削工具において、
（ａ）前記硬質被覆層は、Ａ層とＢ層の二層構造または合計層数が３層以上のＡ層とＢ層の交互積層構造からなり、かつ基材直上にＡ層、最表面にＢ層が存在しており、
（ｂ）前記Ａ層は、０．１〜３．０μｍの一層平均層厚を有し、
組成式：（Ｔｉ１−ｘＡｌｘ）Ｎで表した場合、
０．４≦ｘ≦０．７（ただし、ｘは原子比）を満足する平均組成を有し、
（ｃ）前記Ｂ層は、０．１〜３．０μｍの一層平均層厚を有し、
組成式：（Ａｌ１−ａ−ｂ−ｃＣｒａＳｉｂＣｕｃ）Ｎで表した場合、
０．１５≦ａ≦０．４０、０．０５≦ｂ≦０．２０、０．００５≦ｃ≦０．０５（ただし、ａ、ｂ、ｃはいずれも原子比）を満足する平均組成を有し、さらに、
（ｄ）前記Ｂ層は、層厚方向に沿ってＣｒ成分濃度が周期的に変化する組成変調構造を有し、
（ｅ）前記組成変調構造におけるＣｒ成分濃度の周期的な変化は、Ｃｒ成分の最高含有点とＣｒ成分の最低含有点が１ｎｍ〜１００ｎｍの間隔で繰り返され、
（ｆ）前記Ｃｒ成分の最高含有点におけるＣｒ成分の組成の極大値をａｍａｘとしたとき、
ａ＜ａｍａｘ≦１．３ａの範囲内であり、
（ｇ）前記Ｃｒ成分の最低含有点におけるＣｒ成分の組成の極小値をａｍｉｎとしたとき、
０．７ａ≦ａｍｉｎ＜ａの範囲内である、
ことを特徴とする表面被覆切削工具。」
を特徴とするものである。
This invention has been made based on the above findings,
“In a surface-coated cutting tool in which a hard coating layer having a total average layer thickness of 0.5 to 4.0 μm is provided on the surface of a tool base made of a cubic boron nitride sintered body,
(A) The hard coating layer has a two-layer structure of an A layer and a B layer or an alternately laminated structure of an A layer and a B layer having a total number of three or more, and the A layer and the outermost surface directly above the substrate. B layer exists,
(B) The A layer has an average layer thickness of 0.1 to 3.0 μm,
When represented by a composition formula: (Ti 1-x Al x ) N,
Having an average composition satisfying 0.4 ≦ x ≦ 0.7 (where x is an atomic ratio),
(C) The B layer has an average layer thickness of 0.1 to 3.0 μm,
When represented by a composition formula: (Al 1-a-b-C c a Si b Cu c ) N,
It has an average composition satisfying 0.15 ≦ a ≦ 0.40, 0.05 ≦ b ≦ 0.20, 0.005 ≦ c ≦ 0.05 (wherein a, b, and c are atomic ratios). And then
(D) The B layer has a composition modulation structure in which the Cr component concentration periodically changes along the layer thickness direction,
(E) The periodic change of the Cr component concentration in the composition modulation structure is repeated at intervals of 1 nm to 100 nm between the highest content point of the Cr component and the lowest content point of the Cr component,
(F) When the maximum value of the composition of the Cr component at the highest content point of the Cr component is amax,
a <amax ≦ 1.3a,
(G) When the minimum value of the composition of the Cr component at the minimum content point of the Cr component is amin,
0.7a ≦ amin <a.
A surface-coated cutting tool characterized by that. "
It is characterized by.
つぎに、この発明の被覆工具について、詳細に説明する。 Next, the coated tool of the present invention will be described in detail.
工具基体：
本発明では、立方晶窒化硼素焼結体を工具基体として用いる。
立方晶窒化硼素焼結体を構成する成分、組成について特別な制限はないが、より好ましい構成としては、前記立方晶窒化硼素焼結体は、立方晶窒化硼素粒子と、Ｔｉの窒化物、炭化物、炭窒化物、硼化物およびＡｌの窒化物、酸化物からなる群から選ばれる少なくとも１種以上と不可避不純物を含む結合相からなり、前記立方晶窒化硼素粒子の平均粒径は０．５〜５．０μｍかつ焼結体を作製するための原料粉全体に占める立方晶窒化硼素粒子の含有割合は３０〜８０体積％である。これは、立方晶窒化硼素粒子の平均粒径が５．０μｍを超えると硬質被覆層との密着性が低いｃＢＮ粒子との接触面積が大きくなり、硬質被覆層と立方晶窒化硼素焼結体との付着強度が低下し、硬質被覆層の剥離を伴う異常損傷が生じやすくなり、一方、０．５μｍ未満になると硬質粒子としてのｃＢＮ粒子の機能が十分に発揮できず、耐摩耗性が低下するためである。また、立方晶窒化硼素粒子の含有割合が３０ｖｏｌ％未満では、焼結体の強度が低下し、一方、８０ｖｏｌ％を超えると焼結時の焼結性が低下してくるからである。
Tool base:
In the present invention, a cubic boron nitride sintered body is used as a tool base.
There are no particular restrictions on the components and composition of the cubic boron nitride sintered body. However, as a more preferable configuration, the cubic boron nitride sintered body includes cubic boron nitride particles, Ti nitride, and carbide. , Carbon nitride, boride and nitride of Al, consisting of a binder phase containing at least one selected from the group consisting of oxides and inevitable impurities, the average particle size of the cubic boron nitride particles is 0.5 ~ The content ratio of the cubic boron nitride particles in the total raw material powder for producing the sintered body is 5.0 to 30% by volume. This is because when the average particle size of the cubic boron nitride particles exceeds 5.0 μm, the contact area with the cBN particles having low adhesion to the hard coating layer increases, and the hard coating layer and the cubic boron nitride sintered body Adhesive strength of the resin is reduced, and abnormal damage accompanied by peeling of the hard coating layer is likely to occur. On the other hand, when the thickness is less than 0.5 μm, the function of the cBN particles as the hard particles cannot be sufficiently exhibited, and the wear resistance is reduced. Because. Further, when the content ratio of the cubic boron nitride particles is less than 30 vol%, the strength of the sintered body is lowered, whereas when it exceeds 80 vol%, the sinterability at the time of sintering is lowered.
硬質被覆層を構成するＡ層：
本発明では、硬質被覆層を、（Ｔｉ，Ａｌ）Ｎ層からなるＡ層と、（Ａｌ，Ｃｒ，Ｓｉ，Ｃｕ）Ｎ層からなるＢ層とで構成する。
（Ｔｉ，Ａｌ）Ｎ層からなるＡ層は、高温強度を有し、また、工具基体および（Ａｌ，Ｃｒ，Ｓｉ，Ｃｕ）Ｎ層からなるＢ層のいずれに対してもすぐれた密着強度を有するため、硬質被覆層の耐チッピング性、耐剥離性向上に寄与する。
Ａ層を、組成式：（Ｔｉ１−ｘＡｌｘ）Ｎで表した場合、ＴｉとＡｌの合量に占めるＡｌの平均含有割合ｘ（原子比）は、０．４≦ｘ≦０．７を満足する値とする。
これは、ｘの値が０．４未満では、Ａ層の高温硬さおよび高温耐酸化性が低下し、一方、ｘの値が０．７を超えると、相対的なＴｉ含有割合の減少により、十分な高温強度を確保することができなくなるという理由による。
なお、ｘの値が０．４〜０．７の範囲では、通常、（Ｔｉ，Ａｌ）Ｎ層はその大部分が立方晶構造の結晶粒から構成される。しかし、ｘの値が０．７の近傍の場合に、層中に微量の六方晶構造の結晶粒が出現することもあるが、耐摩耗性への実質的な悪影響は少ないので、ｘの値が０．４〜０．７の範囲内であれば、（Ｔｉ，Ａｌ）Ｎ層中に微量の六方晶構造の結晶粒が存在することは許容される。
A layer constituting the hard coating layer:
In the present invention, the hard coating layer is composed of an A layer composed of a (Ti, Al) N layer and a B layer composed of an (Al, Cr, Si, Cu) N layer.
The A layer made of the (Ti, Al) N layer has high-temperature strength, and has excellent adhesion strength for both the tool base and the B layer made of the (Al, Cr, Si, Cu) N layer. Therefore, it contributes to improvement of chipping resistance and peeling resistance of the hard coating layer.
When the layer A is represented by the composition formula: (Ti 1-x Al x ) N, the average content ratio x (atomic ratio) of Al in the total amount of Ti and Al is 0.4 ≦ x ≦ 0.7. Is a value satisfying.
This is because when the value of x is less than 0.4, the high-temperature hardness and high-temperature oxidation resistance of the A layer decrease, whereas when the value of x exceeds 0.7, the relative Ti content decreases. This is because sufficient high-temperature strength cannot be secured.
When the value of x is in the range of 0.4 to 0.7, the (Ti, Al) N layer is usually mostly composed of crystal grains having a cubic structure. However, when the value of x is in the vicinity of 0.7, a small amount of hexagonal crystal grains may appear in the layer, but since the substantial adverse effect on the wear resistance is small, the value of x Is within the range of 0.4 to 0.7, it is allowed that a small amount of hexagonal crystal grains exist in the (Ti, Al) N layer.
硬質被覆層を構成するＢ層：
（Ａｌ，Ｃｒ，Ｓｉ，Ｃｕ）Ｎ層からなるＢ層は、特に、Ｃｕ成分含有による結晶粒微細化が図られることによりすぐれた耐摩耗性を示し、また、Ｂ層が備える衝撃緩和作用によってすぐれた耐クラック性を示す。
Ｂ層を、組成式：（Ａｌ１−ａ−ｂ−ｃＣｒａＳｉｂＣｕｃ）Ｎで表した場合、それぞれの成分の平均含有割合（原子比）を示すａ、ｂ、ｃについては、０．１５≦ａ≦０．４０、０．０５≦ｂ≦０．２０、０．００５≦ｃ≦０．０５（ただし、ａ、ｂ、ｃはいずれも原子比）を満足する値とする。
Ｃｒの平均含有割合を示すａ値（原子比）が、ＡｌとＳｉとＣｕの合量に占める割合で０．１５未満では、最低限必要とされる高温靭性、高温強度を確保することができないため、チッピング、欠損等の原因となるクラックの発生を抑制することができず、一方、同ａ値が０．４０を超えると、相対的なＡｌ含有割合の減少により、摩耗進行が促進することから、ａ値を０．１５〜０．４０と定めた。
また、Ｓｉの平均含有割合を示すｂ値（原子比）が、ＡｌとＣｒとＣｕの合量に占める割合で０．０５未満では、耐熱塑性変形性の改善による耐摩耗性向上を期待することはできず、一方、同ｂ値が０．２０を超えると、耐摩耗性向上効果に低下傾向がみられるようになることから、ｂ値を０．０５〜０．２０と定めた。
さらに、Ｃｕの平均含有割合を示すｃ値（原子比）が、ＡｌとＣｒとＳｉの合量に占める割合で０．００５未満では、結晶粒微細化による耐摩耗性向上効果を期待することができず、一方、同ｃ値が０．０５を超えると、アークイオンプレーティング（以下、「ＡＩＰ」で示す。）装置によって（Ａｌ，Ｃｒ，Ｓｉ，Ｃｕ）Ｎ層を成膜する際にパーティクルが発生しやすくなり、衝撃的・断続的な高負荷が作用する切削加工において耐クラック性が低下することから、ｃ値を０．００５〜０．０５と定めた。 また、本発明のＢ層を構成する結晶に関しては、特定の結晶構造を有する必要はないが、立方晶構造を有する結晶、または、六方晶構造を有する結晶、または、立方晶構造の結晶と六方晶構造の結晶とが混在したもの、のいずれかであることが好ましい。なお、上記ａ、ｂ、ｃについて、好ましい範囲は、それぞれ、０．１５≦ａ≦０．２５、０．０５≦ｂ≦０．１５、０．０１≦ｃ≦０．０３である。
B layer constituting the hard coating layer:
The B layer composed of the (Al, Cr, Si, Cu) N layer exhibits excellent wear resistance due to the refinement of crystal grains due to the inclusion of the Cu component, and the impact mitigating action provided by the B layer. Excellent crack resistance.
When the B layer is represented by a composition formula: (Al 1-ab-c Cr a Si b Cu c ) N, a, b, and c indicating the average content ratio (atomic ratio) of each component, The values satisfy 0.15 ≦ a ≦ 0.40, 0.05 ≦ b ≦ 0.20, 0.005 ≦ c ≦ 0.05 (where a, b, and c are atomic ratios).
When the a value (atomic ratio) indicating the average content ratio of Cr is less than 0.15 in the ratio of the total amount of Al, Si, and Cu, the minimum required high temperature toughness and high temperature strength cannot be ensured. Therefore, the occurrence of cracks that cause chipping, chipping, etc. cannot be suppressed. On the other hand, if the value a exceeds 0.40, the progress of wear is promoted by the decrease in the relative Al content ratio. Therefore, the a value was determined to be 0.15 to 0.40.
In addition, if the b value (atomic ratio) indicating the average content ratio of Si is less than 0.05 in the total amount of Al, Cr and Cu, it is expected to improve wear resistance by improving the heat plastic deformation property. On the other hand, if the b value exceeds 0.20, the wear resistance improving effect tends to decrease, so the b value was set to 0.05 to 0.20.
Furthermore, if the c value (atomic ratio) indicating the average content ratio of Cu is less than 0.005 in the ratio of the total amount of Al, Cr and Si, the effect of improving the wear resistance by crystal grain refinement can be expected. On the other hand, if the c value exceeds 0.05, particles are formed when the (Al, Cr, Si, Cu) N layer is formed by an arc ion plating (hereinafter referred to as “AIP”) apparatus. Since the crack resistance is lowered in the cutting process in which impacts and intermittent high loads act, the c value is determined to be 0.005 to 0.05. Further, the crystal constituting the B layer of the present invention does not need to have a specific crystal structure, but it has a cubic crystal structure, a hexagonal crystal structure, a cubic crystal structure and a hexagonal structure. It is preferably any of those mixed with crystals having a crystal structure. In addition, about said a, b, and c, a preferable range is 0.15 <= a <= 0.25, 0.05 <= b <= 0.15, 0.01 <= c <= 0.03, respectively.
硬質被覆層の層構造：
本発明では、硬質被覆層は、Ａ層とＢ層とで構成されるが、層構造の一つの態様として、図１に示すＡ層とＢ層との二層構造をあげることができる。
また、別の態様としては、図２に示すようにＡ層とＢ層との合計層数が３層以上の交互積層構造をあげることができる。
なお、前記Ｂ層は図１（ｂ）〜（ｄ）に示すように、Ｂ層内にＣｒ成分濃度が周期的に変化する組成変調構造を有する。
なお、Ａ層、Ｂ層の平均層厚は、前記いずれの層構造の場合であっても、それぞれ、０．１〜３．０μｍの範囲内とする。
これは、Ａ層の平均層厚が０．１μｍ未満では、工具基体あるいはＢ層との密着強度向上効果が少なく、一方、Ａ層の平均層厚が３．０μｍを超えると、残留圧縮応力の蓄積により、クラックが発生しやすくなり安定した密着力を確保できなくなることから、Ａ層の平均層厚は、０．１〜３．０μｍ、望ましくは、０．３〜２．０μｍと定めた。
また、Ｂ層の平均層厚が０．１μｍ未満では、長期の使用にわたってすぐれた耐摩耗性を発揮することはできず、一方、その平均層厚が３．０μｍを超えると、チッピング、欠損を発生しやすくなるので、Ｂ層の平均層厚は、０．１〜３．０μｍ、望ましくは、０．３〜２．０μｍと定めた。
さらに、Ａ層とＢ層からなる硬質被覆層の合計平均層厚が０．５μｍ未満では、長期にわたる十分な耐摩耗性を発揮することができず、一方、合計層厚が４．０μｍを超えると硬質被覆層が自壊を生じやすくなることから、硬質被覆層の合計平均層厚は０．５〜４．０μｍと定めた。
また、工具基体と硬質被覆層の密着性確保との観点から、工具基体の表面直上にはＡ層を成膜し、一方、切削初期の衝撃緩和との観点から、硬質被覆層の最表面をＢ層で形成することとする。このような層構造とすることで、硬質被覆層と高い付着強度を得ることが困難な立方晶窒化硼素焼結体を基体とした表面被覆切削工具においても、Ｂ層が備える衝撃緩和作用を十全に発揮させることが可能となる。
Layer structure of hard coating layer:
In the present invention, the hard coating layer is composed of an A layer and a B layer. As one embodiment of the layer structure, a two-layer structure of an A layer and a B layer shown in FIG. 1 can be given.
Further, as another embodiment, as shown in FIG. 2, an alternate laminated structure in which the total number of layers A and B is three or more can be given.
The B layer has a composition modulation structure in which the Cr component concentration periodically changes in the B layer, as shown in FIGS.
In addition, the average layer thickness of A layer and B layer shall be in the range of 0.1-3.0 micrometers, respectively, also in the case of any said layer structure.
If the average layer thickness of the A layer is less than 0.1 μm, the effect of improving the adhesion strength with the tool substrate or the B layer is small. On the other hand, if the average layer thickness of the A layer exceeds 3.0 μm, the residual compressive stress Since accumulation tends to generate cracks and stable adhesion cannot be ensured, the average layer thickness of the A layer is set to 0.1 to 3.0 μm, preferably 0.3 to 2.0 μm.
In addition, when the average layer thickness of the B layer is less than 0.1 μm, excellent wear resistance cannot be exhibited over a long period of use. On the other hand, when the average layer thickness exceeds 3.0 μm, chipping and defects are not caused. Since it becomes easy to generate | occur | produce, the average layer thickness of B layer was set to 0.1-3.0 micrometers, desirably 0.3-2.0 micrometers.
Furthermore, if the total average layer thickness of the hard coating layers composed of the A layer and the B layer is less than 0.5 μm, sufficient wear resistance over a long period cannot be exhibited, while the total layer thickness exceeds 4.0 μm. Since the hard coating layer tends to be self-destructing, the total average layer thickness of the hard coating layer was determined to be 0.5 to 4.0 μm.
In addition, from the viewpoint of ensuring adhesion between the tool base and the hard coating layer, an A layer is formed directly on the surface of the tool base, while from the viewpoint of impact mitigation at the initial stage of cutting, the outermost surface of the hard coating layer is formed. The layer B is formed. With such a layer structure, even in a surface-coated cutting tool based on a cubic boron nitride sintered body that is difficult to obtain a hard coating layer and high adhesion strength, the impact mitigating action of the B layer can be sufficiently reduced. It will be possible to fully demonstrate.
Ｂ層の組成：
図１に示す組成変調構造を有するＢ層を成膜するに際しては、例えば図３に示すように、アークイオンプレーティング（以下、「ＡＩＰ」と記す）装置内に、Ａ層形成用の所定組成のＴｉ−Ａｌ合金ターゲットを配置するとともに、組成変調構造を形成するための２種類のＡｌ−Ｃｒ−Ｓｉ−Ｃｕ合金ターゲットをそれぞれ配置することで実施する。
前記２種類のＡｌ−Ｃｒ−Ｓｉ−Ｃｕ合金ターゲットは、Ｂ層の組成変調におけるＣｒ成分濃度の最高含有点を形成するＣｒ成分最高含有点形成用Ａｌ−Ｃｒ−Ｓｉ−Ｃｕ合金ターゲットと、Ｂ層の組成変調におけるＣｒ成分濃度の最低含有点を形成するＣｒ成分最低含有点形成用Ａｌ−Ｃｒ−Ｓｉ−Ｃｕ合金ターゲットである。
Composition of layer B:
When forming the B layer having the composition modulation structure shown in FIG. 1, for example, as shown in FIG. 3, a predetermined composition for forming the A layer is provided in an arc ion plating (hereinafter referred to as “AIP”) apparatus. The Ti—Al alloy target is arranged, and two types of Al—Cr—Si—Cu alloy targets for forming the composition modulation structure are respectively arranged.
The two types of Al—Cr—Si—Cu alloy targets include a Cr component highest content point forming Al—Cr—Si—Cu alloy target that forms the highest content point of the Cr component concentration in the composition modulation of the B layer, and B It is an Al-Cr-Si-Cu alloy target for forming a Cr component minimum content point that forms the minimum content point of the Cr component concentration in the compositional modulation of the layer.
組成変調構造を有するＢ層の成膜に当たっては、図３に示すＡＩＰ装置において、回転テーブル上で自転しながら回転する工具基体とＣｒ最高含有点形成用ターゲットとの間にアーク放電を発生させて成膜すると同時に、回転テーブル上で自転しながら回転する工具基体とＣｒ最低含有点形成用ターゲットとの間にもアーク放電を発生させて成膜することによって、Ｃｒ成分濃度が層厚方向に沿って周期的かつ連続的に変化する組成変調構造（図１（ｃ）参照）を有するＢ層を形成することができる。
また、上記の成膜工程において、工具基体とＣｒ最高含有点形成用ターゲット（あるいはＣｒ最低含有点形成用ターゲット）との間にアーク放電を発生させて成膜したのちアーク放電を停止し、次いで、工具基体とＣｒ最低含有点形成用ターゲット（あるいはＣｒ最高含有点形成用ターゲット）との間にアーク放電を発生させて成膜したのちアーク放電を停止する、という前記操作を交互に繰り返し行うことにより、Ｃｒ成分濃度が層厚方向に沿って周期的にかつ不連続的(ステップ状)に変化する組成変調構造（図１（ｄ）参照）を有するＢ層を形成することができる。
本発明は組成変調構造の形態に関して、Ｃｒの成分濃度変化が連続的または不連続的のいずれの形態であっても構わないが、切刃に対して衝撃的・断続的な高負荷が作用する切削加工において、硬質被覆層の耐摩耗性および耐熱性向上効果を発揮させつつ、かつ層全体として耐クラック性を向上させる観点からは、Ｃｒ最高含有点とＣｒ最低含有点の間の層内の親和性を高めるため、組成変調構造のＣｒの成分濃度変化が連続的に変化することがより好ましい。
≪影山コメント：図１（ｃ）、（ｄ）を追加しました。≫
ここでいう最高含有点、最低含有点について説明する。ここでいうＣｒの最高含有点とは、層厚方向に沿って測定した各測定点におけるＣｒ成分の濃度が、Ｂ層全体の組成式（Ａｌ１−ａ−ｂ−ｃＣｒａＳｉｂＣｕｃ）ＮにおけるＣｒ成分の平均濃度割合ａの値を連続して超えている部分における極大値を言い、ａの値を連続して超えている部分が複数ある場合は、それぞれの部分における極大値をそれぞれの部分における最高含有点と定義する。同様に、ここでいう最低含有点とは、層厚方向に沿って測定した各測定点におけるＣｒ成分の平均濃度割合ａが、Ｂ層全体の組成式（Ａｌ１−ａ−ｂ−ｃＣｒａＳｉｂＣｕｃ）ＮにおけるＣｒ成分の平均濃度割合ａの値未満となる連続した部分における極小値を言い、連続してａの値未満となる部分が複数ある場合は、それぞれの部分における極小値をそれぞれの部分における最小含有点と定義する。この定義によれば、ａの値近傍での周期的な変化において、図１（ｂ）に示すように、最高含有点と最低含有点が交互に出現する。
In forming the B layer having the composition modulation structure, arc discharge is generated between the tool base rotating while rotating on the rotary table and the target for forming the highest Cr content in the AIP apparatus shown in FIG. At the same time as the film is formed, by generating an arc discharge between the tool base that rotates while rotating on the rotary table and the target for forming the lowest Cr content point, the Cr component concentration follows the layer thickness direction. Thus, a B layer having a composition modulation structure (see FIG. 1C) that periodically and continuously changes can be formed.
Further, in the above film forming step, arc discharge is generated between the tool base and the target for forming the highest Cr content point (or target for forming the lowest Cr content point) to stop the arc discharge. The above operation of alternately stopping the arc discharge after forming an arc discharge between the tool base and the target for forming the lowest Cr content point (or target for forming the highest Cr content point) is alternately performed. Thus, the B layer having a composition modulation structure (see FIG. 1D) in which the Cr component concentration changes periodically and discontinuously (step-like) along the layer thickness direction can be formed.
In the present invention, regarding the form of the compositional modulation structure, the Cr component concentration change may be either continuous or discontinuous, but a shocking and intermittent high load acts on the cutting edge. In cutting, while exhibiting the effect of improving the wear resistance and heat resistance of the hard coating layer, and from the viewpoint of improving the crack resistance as a whole layer, in the layer between the Cr highest content point and the Cr lowest content point In order to increase the affinity, it is more preferable that the Cr component concentration change of the composition modulation structure is continuously changed.
≪Kageyama comment: Added Figure 1 (c) and (d). ≫
Here, the maximum content point and the minimum content point will be described. The highest content point of Cr here is the concentration of Cr component at each measurement point measured along the layer thickness direction, where the composition formula of the entire B layer (Al 1-a-bc Cr a Si b Cu c ) Refers to the maximum value in the portion that continuously exceeds the value of the average concentration ratio a of the Cr component in N. When there are a plurality of portions that continuously exceed the value of a, the maximum value in each portion is determined. It is defined as the highest content point in each part. Similarly, the lowest content point here is the average concentration ratio a of the Cr component at each measurement point measured along the layer thickness direction, and the composition formula (Al 1-a-bc Cr a of the entire B layer. The minimum value in the continuous part which becomes less than the value of the average concentration ratio a of the Cr component in Si b Cu c ) N. When there are a plurality of parts which continuously become less than the value of a, the minimum value in each part Is defined as the minimum content point in each part. According to this definition, the highest content point and the lowest content point appear alternately as shown in FIG.
組成変調構造を有するＢ層におけるＣｒ最高含有点におけるＣｒ濃度：
Ｂ層のＣｒ最高含有点（図１（ｂ）参照）におけるＣｒ成分は、Ｂ層自体の強度を向上させ、耐クラック性を向上させる作用をもつが、Ｃｒ最高含有点におけるＣｒの含有割合を示すａｍａｘが、１．３ａ（ただし、ａの値は、Ｂ層の組成式：（Ａｌ１−ａ−ｂ−ｃＣｒａＳｉｂＣｕｃ）におけるＣｒの平均組成ａを示す）より大きくなると、相対的に、Ａｌ、Ｓｉ、Ｃｕの含有割合が減少するため、高硬度を有するＣｒ最低含有点が隣接して存在してもＢ層としての耐熱性、耐摩耗性の低下は避けられず、一方、各Ｃｒ最高含有点におけるＣｒの含有割合を示すａｍａｘは、その定義により、ａ以下の値を取らないことから、Ｃｒ最高含有点におけるＣｒ濃度ａｍａｘの値は、ａを超え１．３ａ以下の値とすることが必要であり、１．０３ａ≦ａｍａｘ≦１．２５ａを満足することが望ましい。
Cr concentration at the highest Cr content point in the B layer having a composition modulation structure:
The Cr component at the highest Cr content point of the B layer (see FIG. 1B) has the effect of improving the strength of the B layer itself and improving crack resistance, but the Cr content at the highest Cr content point amax indicated, 1.3a (provided that the value of a is, the composition formula of the B layer: (Al 1-a-b -c Cr a Si b Cu c) shows the average composition a of Cr in) the more increases, Relatively, since the content ratio of Al, Si, Cu is reduced, even if the Cr minimum content point having a high hardness exists adjacent to the B layer, the heat resistance and wear resistance are inevitably lowered. On the other hand, amax indicating the content ratio of Cr at each Cr highest content point does not take a value of a or less according to the definition. Therefore, the value of the Cr concentration amax at the Cr highest content point exceeds a and exceeds 1.3a. Must be the value of 1 It is desirable to satisfy the 03a ≦ amax ≦ 1.25a.
組成変調構造を有するＢ層におけるＣｒ最低含有点におけるＣｒ濃度：
前記のとおり、Ｃｒ最高含有点は相対的に高強度を有し、耐クラック性を向上させるが、その反面、相対的に硬度が小さく耐摩耗性に劣り、また耐熱性にも劣るものであるため、このＣｒ最高含有点の耐摩耗性不足、耐熱性不足を補うため、Ｃｒ含有割合を相対的に小さくし、これによって層全体としての耐摩耗性、耐熱性を向上させるＣｒ最低含有点（図１（ｂ）参照）を厚さ方向に交互に周期的に形成する。
しかし、Ｃｒ最低含有点におけるＣｒの含有割合を示すａｍｉｎが、Ｂ層の組成式におけるＣｒの平均組成を示す０．７ａ未満の値であると、相対的に、Ａｌ、Ｓｉ、Ｃｕの含有割合が高くなるため、高強度を有するＣｒ最高含有点が隣接して存在しても層全体としての耐クラック性の低下が避けられなくなり、耐摩耗性向上効果、耐熱性向上効果を十全に発揮できず、一方、Ｃｒ最低含有点におけるＣｒの含有割合を示すａｍｉｎは、その定義により、ａ以上の数値とならないことから、Ｂ層のＣｒ最低含有点におけるＣｒ濃度ａｍｉｎの値は、０．７ａ以上ａ未満の値とすることが必要であり、０．７５ａ≦ａｍｉｎ≦０．９７ａを満足することが望ましい。
Cr concentration at the lowest Cr content point in the B layer having the composition modulation structure:
As described above, the highest Cr content point has relatively high strength and improves crack resistance, but on the other hand, it has relatively small hardness and poor wear resistance, and also has poor heat resistance. Therefore, in order to compensate for the insufficient wear resistance and insufficient heat resistance of the highest Cr content point, the Cr content ratio is relatively reduced, thereby improving the wear resistance and heat resistance of the entire layer ( 1B) are periodically and alternately formed in the thickness direction.
However, when amin indicating the content ratio of Cr at the lowest Cr content point is a value less than 0.7a indicating the average composition of Cr in the composition formula of the B layer, the content ratio of Al, Si, and Cu is relatively Therefore, even if the highest Cr content point with high strength exists adjacently, the crack resistance of the entire layer is inevitably lowered, and the effect of improving wear resistance and heat resistance is fully exhibited. On the other hand, amin indicating the content ratio of Cr at the Cr minimum content point cannot be a numerical value equal to or more than a by its definition. Therefore, the value of the Cr concentration amin at the Cr minimum content point of the B layer is 0.7a. It is necessary to make the value less than a above, and it is desirable to satisfy 0.75a ≦ amin ≦ 0.97a.
組成変調構造を有するＢ層のＣｒ最高含有点とＣｒ最低含有点の間隔：
Ｃｒ最高含有点とＣｒ最低含有点の間隔が１ｎｍ未満では、それぞれの点を明確に区別して形成することが困難であり、その結果、Ｂ層に所望の高強度、高温硬さと耐熱性を確保することができなくなり、また、その間隔が１００ｎｍを越えるとそれぞれの点がもつ欠点、すなわちＣｒ最低含有点であれば強度不足、Ｃｒ最高含有点であれば高温硬さと耐熱性不足がＢ層内に局部的に現れ、これが原因で切刃にクラックが発生し易くなり、また、摩耗進行が促進されるようになることから、Ｃｒ最高含有点とＣｒ最低含有点の間隔は１ｎｍ以上１００ｎｍ以下とする。
Interval between the highest Cr content point and the lowest Cr content point of the B layer having a composition modulation structure:
If the interval between the highest Cr content point and the lowest Cr content point is less than 1 nm, it is difficult to clearly distinguish each point and form the desired high strength, high temperature hardness and heat resistance for the B layer. In addition, when the distance exceeds 100 nm, the disadvantages of the respective points, that is, if the Cr minimum content point is insufficient strength, if the Cr maximum content point is high temperature hardness and insufficient heat resistance in the B layer The cracks are likely to occur in the cutting edge due to this, and the progress of wear is promoted, so the interval between the highest Cr content point and the lowest Cr content point is 1 nm or more and 100 nm or less. To do.
Ａ層とＢ層の二層構造からなる硬質被覆層：
図１に示す本発明の二層構造の硬質被覆層は、工具基体表面直上に、まず、所定平均組成、所定平均層厚のＡ層を成膜し、次いで、Ａ層の表面に、所定平均組成、所定平均層厚のＢ層を成膜することによって形成される。
Ａ層、Ｂ層の成膜は、例えば、図３に示すように、Ａ層形成用の所定組成のＴｉ−Ａｌ合金ターゲットとＢ層形成用の所定組成のＡｌ−Ｃｒ−Ｓｉ−Ｃｕ合金ターゲットを配置したＡＩＰ装置内での物理蒸着によって成膜することができる。
Hard coating layer comprising a two-layer structure of A layer and B layer:
The hard coating layer having a two-layer structure of the present invention shown in FIG. 1 is formed by first depositing an A layer having a predetermined average composition and a predetermined average layer thickness directly on the surface of the tool substrate, and then forming a predetermined average on the surface of the A layer. It is formed by depositing a B layer having a composition and a predetermined average layer thickness.
For example, as shown in FIG. 3, the A layer and the B layer are formed by a Ti-Al alloy target having a predetermined composition for forming the A layer and an Al-Cr-Si-Cu alloy target having a predetermined composition for forming the B layer. The film can be formed by physical vapor deposition in an AIP apparatus in which is disposed.
Ａ層とＢ層の交互積層構造からなる硬質被覆層：
図２に示すような交互積層構造からなる本発明の硬質被覆層は、例えば、図３に示すＡ層形成用の所定組成のＴｉ−Ａｌ合金ターゲットとＢ層形成用の所定組成のＡｌ−Ｃｒ−Ｓｉ−Ｃｕ合金ターゲットを配置したＡＩＰ装置内での物理蒸着を行うにあたり、工具基体表面直上に、まず、所定平均組成、所定平均層厚のＡ層を成膜し、次いで、Ａ層の表面に、所定平均組成、所定平均層厚のＢ層を成膜し、さらに、Ａ層とＢ層の成膜を、所定の目標層厚になるまで交互に繰り返し行うことにより、合計層数が３層以上のＡ層とＢ層の交互積層構造からなる硬質被覆層を形成することができる。
工具基体の表面直上にＡ層が形成され、また、硬質被覆層の最表面にはＢ層が形成されている好ましい形態の交互積層構造においては、Ａ層とＢ層の合計層数は、自ずと４層以上の偶数となる。
Hard coating layer comprising an alternating layered structure of A and B layers:
The hard coating layer of the present invention having an alternately laminated structure as shown in FIG. 2 includes, for example, a Ti—Al alloy target having a predetermined composition for forming an A layer and an Al—Cr having a predetermined composition for forming a B layer shown in FIG. -When performing physical vapor deposition in an AIP apparatus in which a Si-Cu alloy target is disposed, a layer A having a predetermined average composition and a predetermined average layer thickness is formed directly on the surface of the tool base, and then the surface of the A layer In addition, a B layer having a predetermined average composition and a predetermined average layer thickness is formed, and further, the A layer and the B layer are alternately formed repeatedly until a predetermined target layer thickness is obtained. It is possible to form a hard coating layer composed of an alternately laminated structure of A layers and B layers equal to or more than one layer.
In the preferred alternate layered structure in which the A layer is formed directly on the surface of the tool base and the B layer is formed on the outermost surface of the hard coating layer, the total number of layers of the A layer and the B layer is naturally Even number of 4 layers or more.
本発明の被覆工具は、硬質被覆層を、（Ｔｉ，Ａｌ）Ｎ層からなるＡ層と（Ａｌ，Ｃｒ，Ｓｉ，Ｃｕ）Ｎ層からなるＢ層とで構成し、かつ、その層構造を、Ａ層とＢ層の二層構造あるいはＡ層とＢ層の交互積層構造として構成することにより、硬質被覆層全体としての耐クラック性と耐摩耗性を同時に向上させることができる。
さらに、前記Ｂ層について、Ｃｒ成分濃度が周期的に変化する組成変調構造の層として構成することにより、硬質被覆層全体としての耐チッピング性と耐摩耗性をさらに向上させることができる。
したがって、本発明の被覆工具は、高熱発生を伴い、かつ、切刃に対して大きな衝撃的・断続的高負荷がかかる焼入れ鋼などの高硬度鋼の強断続切削加工でも、すぐれた耐クラック性およびすぐれた耐摩耗性を長期に亘って発揮するものである。
In the coated tool of the present invention, the hard coating layer is composed of an A layer composed of a (Ti, Al) N layer and a B layer composed of an (Al, Cr, Si, Cu) N layer, and the layer structure thereof. By configuring as a two-layer structure of A layer and B layer or an alternately laminated structure of A layer and B layer, the crack resistance and wear resistance of the entire hard coating layer can be improved at the same time.
Furthermore, by configuring the B layer as a layer having a composition modulation structure in which the Cr component concentration changes periodically, the chipping resistance and wear resistance of the entire hard coating layer can be further improved.
Therefore, the coated tool of the present invention has excellent crack resistance even in high-strength cutting of hardened steel such as hardened steel, which is accompanied by high heat generation and has a large impact and intermittent high load on the cutting edge. And excellent wear resistance over a long period of time.
つぎに、この発明の被覆工具を実施例により具体的に説明する。 Next, the coated tool of the present invention will be specifically described with reference to examples.
工具基体の作製：
原料粉末として、０．５〜５．０μｍの平均粒径を有するｃＢＮ粒子を硬質相形成用原料粉末として用意するとともに、いずれも１．０μｍ以下の平均粒径を有するＴｉＮ粉末、ＴｉＣ粉末、ＴｉＣＮ粉末、Ａｌ粉末、ＡｌＮ粉末、Ａｌ２Ｏ３粉末を結合相形成用原料粉末として用意する。
これら中からいくつかの原料粉末とｃＢＮ粉末を、焼結後のｃＢＮ粒子の含有割合が３０〜８０体積％となるように表１に示される配合比で配合する。
次いで、この原料粉末をボールミルで７２時間湿式混合し、乾燥した後、成形圧１２０ＭＰａで直径：５０ｍｍ×厚さ：１．５ｍｍの寸法にプレス成形し、ついでこの成形体を、圧力：１Ｐａ以下の真空雰囲気中、９００〜１３００℃の範囲内の所定温度に保持して仮焼結し、その後、超高圧焼結装置に装入して、圧力：５ＧＰa、温度：１２００〜１４００℃の範囲内の所定の温度で焼結することにより、ｃＢＮ焼結体を作製する。
この焼結体をワイヤー放電加工機で所定寸法に切断し、Ｃｏ：５質量％、ＴａＣ：５質量％、ＷＣ：残りの組成およびＩＳＯ規格ＣＮＧＡ１２０４０８のインサート形状をもったＷＣ基超硬合金製インサート本体のろう付け部（コーナー部）に、質量％で、Ｃｕ：２６％、Ｔｉ：５％、Ａｇ：残りからなる組成を有するＡｇ系ろう材を用いてろう付けし、上下面および外周研磨、ホーニング処理を施すことによりＩＳＯ規格ＣＮＧＡ１２０４０８のインサート形状をもったｃＢＮ工具基体１〜３を製造した。
Tool substrate production:
As raw material powder, cBN particles having an average particle diameter of 0.5 to 5.0 μm are prepared as hard phase forming raw material powders, and all of them are TiN powder, TiC powder, TiCN having an average particle diameter of 1.0 μm or less. Powder, Al powder, AlN powder, and Al 2 O 3 powder are prepared as binder phase forming raw material powder.
Among these, some raw material powders and cBN powders are blended at a blending ratio shown in Table 1 so that the content ratio of cBN particles after sintering is 30 to 80% by volume.
Next, the raw material powder was wet-mixed for 72 hours in a ball mill, dried, and then press-molded with a molding pressure of 120 MPa to a size of diameter: 50 mm × thickness: 1.5 mm. In a vacuum atmosphere, it is preliminarily sintered while being held at a predetermined temperature in the range of 900 to 1300 ° C., and then charged into an ultra-high pressure sintering apparatus, pressure: 5 GPa, temperature: in the range of 1200 to 1400 ° C. A cBN sintered body is prepared by sintering at a predetermined temperature.
This sintered body is cut into a predetermined size with a wire electric discharge machine, Co: 5% by mass, TaC: 5% by mass, WC: remaining composition and insert made of WC-based cemented carbide with ISO standard CNGA120408 insert shape Brazing to the brazing part (corner part) of the main body using an Ag-based brazing material having a composition consisting of Cu: 26%, Ti: 5%, and Ag: the rest, and polishing the upper and lower surfaces and outer periphery, By performing the honing process, cBN tool bases 1 to 3 having an insert shape of ISO standard CNGA120408 were manufactured.
（ａ）上記の工具基体１〜３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３に示すＡＩＰ装置の回転テーブル上の中心軸から半径方向に所定距離離れた位置に外周部にそって装着し、ＡＩＰ装置内に、所定組成のＡ層形成用Ｔｉ−Ａｌ合金ターゲット（カソード電極）を配置するとともに、Ｂ層形成用のターゲットとして、Ｃｒ最高含有点形成用Ａｌ−Ｃｒ−Ｓｉ−Ｃｕ合金ターゲット（カソード電極）とＣｒ最低含有点形成用Ａｌ−Ｃｒ−Ｓｉ−Ｃｕ合金ターゲット（カソード電極）を対向して配置し、
（ｂ）まず、装置内を排気して真空に保持しながら、ヒータで工具基体を４００℃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工具基体に−１０００Ｖの直流バイアス電圧を印加し、かつ、Ｔｉ−Ａｌ合金ターゲット（カソード電極）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、もって工具基体表面をボンバード洗浄し、（ｃ）ついで、装置内に反応ガスとして窒素ガスを導入して表２に示す窒素圧とすると共に、前記回転テーブル上で自転しながら回転する工具基体の温度を表２に示す温度範囲内に維持するとともに表２に示す直流バイアス電圧を印加し、Ａ層形成用Ｔｉ−Ａｌ合金ターゲット（カソード電極）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、工具基体の表面に、表４に示される所定の組成および一層目標平均層厚のＡ層を蒸着形成し、（ｄ）ついで、同じく装置内に反応ガスとして窒素ガスを導入して表２に示す窒素圧とすると共に、前記回転テーブル上で自転しながら回転する工具基体の温度を表２に示す温度範囲内に維持するとともに表２に示す直流バイアス電圧を印加し、Ｃｒ最高含有点形成用Ａｌ−Ｃｒ−Ｓｉ−Ｃｕ合金ターゲット（カソード電極）とアノード電極、また、Ｃｒ最低含有点形成用Ａｌ−Ｃｒ−Ｓｉ−Ｃｕ合金ターゲット（カソード電極）とアノード電極との間に、同時に１００Ａの電流を流してアーク放電を発生させることにより、前記（ｃ）で成膜したＡ層の表面に、表４に示される所定の組成、目標平均層厚、組成変調の周期、ａｍａｘ、ａｍｉｎからなる連続的なＣｒ成分濃度の変化を有するＢ層を蒸着形成することにより、
硬質被覆層がＡ層とＢ層の二層構造からなり、Ｂ層はＣｒ成分濃度が層厚方向に周期的に連続的に変化する組成変調構造を有する表４に示す本発明被覆工具１〜６（以下、本発明工具１〜６という）をそれぞれ製造した。
（ｅ）また、目標合計平均層厚になるまで前記（ｃ）と（ｄ）を交互に繰り返し行うことにより、硬質被覆層がＡ層とＢ層の交互積層構造からなる表４に示す本発明被覆工具７〜９（以下、本発明工具７〜９という）をそれぞれ製造した。
（ｆ）また、前記（ｄ）の工程において、Ｃｒ最高含有点形成用Ａｌ−Ｃｒ−Ｓｉ−Ｃｕ合金ターゲット（カソード電極）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て成膜したのちこれを停止し、ついで、Ｃｒ最低含有点形成用Ａｌ−Ｃｒ−Ｓｉ−Ｃｕ合金ターゲット（カソード電極）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て成膜したのちこれを停止し、これを交互に繰り返して行うことにより、表３に示される所定の組成、目標平均層厚、組成変調の周期、ａｍａｘ、ａｍｉｎからなる不連続的な（ステップ状の）Ｃｒ成分濃度の変化を有するＢ層を蒸着形成することにより、
硬質被覆層がＡ層とＢ層の二層構造からなり、Ｂ層はＣｒ成分濃度が層厚方向に周期的に不連続的（ステップ状）に変化する組成変調構造を有する表４に示す本発明被覆工具１０〜１５（以下、本発明工具１０〜１５という）をそれぞれ製造した。
（ｇ）さらに、目標合計平均層厚になるまで前記（ｃ）と（ｆ）を交互に繰り返し行うことにより、硬質被覆層がＡ層と不連続的な（ステップ状の）Ｃｒ成分濃度の変化を有するＢ層の交互積層構造からなる表４に示す本発明被覆工具１６〜１８（以下、本発明工具１６〜１８という）をそれぞれ製造した。
(A) Each of the tool bases 1 to 3 is ultrasonically cleaned in acetone and dried, at a position spaced apart from the central axis on the rotary table of the AIP apparatus shown in FIG. 3 by a predetermined distance in the radial direction. Along with the outer periphery, an A-layer forming Ti-Al alloy target (cathode electrode) having a predetermined composition is placed in the AIP apparatus, and as a target for forming the B layer, the highest Cr content point forming Al- A Cr-Si-Cu alloy target (cathode electrode) and a Cr-lowest content point forming Al-Cr-Si-Cu alloy target (cathode electrode) are arranged facing each other.
(B) First, the tool base is heated to 400 ° C. with a heater while the inside of the apparatus is evacuated and kept in vacuum, and then a DC bias voltage of −1000 V is applied to the tool base that rotates while rotating on the rotary table. In addition, an arc discharge is generated by passing a current of 100 A between the Ti—Al alloy target (cathode electrode) and the anode electrode, thereby bombarding the surface of the tool base, and (c) then reacting in the apparatus. Nitrogen gas is introduced as a gas to obtain the nitrogen pressure shown in Table 2, and the temperature of the tool base rotating while rotating on the rotary table is maintained within the temperature range shown in Table 2 and the DC bias shown in Table 2 A voltage is applied to cause a 100 A current to flow between the Ti-Al alloy target (cathode electrode) for forming the A layer (cathode electrode) and the anode electrode, thereby generating an arc discharge. A layer A having a predetermined composition shown in Table 4 and a target average layer thickness is formed on the surface by vapor deposition. (D) Next, nitrogen gas is introduced as a reaction gas into the apparatus, and the nitrogen pressure shown in Table 2 is set. At the same time, the temperature of the tool base rotating while rotating on the rotary table is maintained within the temperature range shown in Table 2, and a DC bias voltage shown in Table 2 is applied to form the highest Cr-containing point Al-Cr- An arc of 100 A is simultaneously applied between the Si-Cu alloy target (cathode electrode) and the anode electrode, and between the Al-Cr-Si-Cu alloy target (cathode electrode) for forming the lowest Cr content point and the anode electrode. By generating a discharge, the surface of the A layer formed in the above (c) is formed on the surface composed of a predetermined composition, target average layer thickness, composition modulation period, amax, and amin shown in Table 4. By vapor deposited layer B having a change of specific Cr component concentration,
The hard coating layer has a two-layer structure of an A layer and a B layer, and the B layer has a composition modulation structure in which the Cr component concentration periodically and continuously changes in the layer thickness direction. 6 (hereinafter referred to as the present invention tools 1 to 6) were produced.
(E) In addition, the present invention shown in Table 4 in which the hard coating layer is composed of an alternately laminated structure of A layers and B layers by repeating the steps (c) and (d) alternately until reaching the target total average layer thickness. Coated tools 7-9 (hereinafter referred to as the present invention tools 7-9) were produced.
(F) Further, in the step (d), an arc discharge is generated by flowing a current of 100 A between the Al-Cr-Si-Cu alloy target for forming the highest Cr content point (cathode electrode) and the anode electrode. Then, this is stopped, and then an arc discharge is generated by flowing a current of 100 A between the Al-Cr-Si-Cu alloy target for forming the lowest Cr content point (cathode electrode) and the anode electrode. After the film is formed, the process is stopped and this process is alternately repeated, thereby performing discontinuous (steps) including the predetermined composition, target average layer thickness, composition modulation period, amax, and amin shown in Table 3. By vapor-depositing a B layer having a change in Cr component concentration,
The hard coating layer has a two-layer structure of an A layer and a B layer, and the B layer has a composition modulation structure in which the Cr component concentration changes periodically and discontinuously (stepwise) in the layer thickness direction. Invention coated tools 10 to 15 (hereinafter referred to as present invention tools 10 to 15) were produced.
(G) Further, by repeating the steps (c) and (f) alternately until the target total average layer thickness is reached, the hard coating layer changes discontinuously with the A layer (step-like) Cr component concentration. The present invention coated tools 16 to 18 (hereinafter referred to as the present invention tools 16 to 18) shown in Table 4 each consisting of an alternately laminated structure of B layers having the following numbers were manufactured.
比較の目的で、図３に示すＡＩＰ装置を用いて、表３に示す成膜条件（本発明とは、ターゲットの成分組成あるいは平均層厚が異なる）で硬質被覆層を形成することにより、硬質被覆層がＡ層とＢ層の二層構造あるいは三層以上の交互積層構造からなり、Ｂ層はＣｒ成分濃度が層厚方向に周期的に連続的あるいは不連続的（ステップ状）に変化する組成変調構造を有する表５に示す比較例被覆工具１〜１８（以下、比較例工具１〜１８という）をそれぞれ製造した。 For the purpose of comparison, a hard coating layer was formed by using the AIP apparatus shown in FIG. 3 and forming a hard coating layer under the film formation conditions shown in Table 3 (the component composition or average layer thickness of the target is different from that of the present invention). The coating layer has a two-layer structure of A layer and B layer or an alternately laminated structure of three or more layers. In the B layer, the Cr component concentration changes periodically or discontinuously (stepwise) in the layer thickness direction. Comparative example-coated tools 1 to 18 (hereinafter referred to as comparative example tools 1 to 18) shown in Table 5 having a composition modulation structure were produced.
上記で作製した本発明工具１〜１８および比較例工具１〜１８の交互積層構造を構成するＡ層、Ｂ層の成分組成を、走査型電子顕微鏡（ＳＥＭ）を用いたエネルギー分散型Ｘ線分析法（ＥＤＳ）により５ヶ所で測定し、その平均値を、Ａ層、Ｂ層の平均組成として求めた。
また、走査型電子顕微鏡を用いた断面観察像において、基体と硬質被覆層の界面粗さの基準線の法線方向のＡ層、Ｂ層の層厚を測定し、硬質被覆層の５ヶ所で同測定を行い、測定値を平均することで、各Ａ層、Ｂ層の平均層厚を算出した。
表４、表５に、測定・算出したそれぞれの値を示す。
Energy dispersive X-ray analysis using a scanning electron microscope (SEM) for the component compositions of the A layer and B layer constituting the alternately laminated structure of the inventive tools 1 to 18 and the comparative tools 1 to 18 produced above. The average value was determined as the average composition of the A layer and the B layer.
Also, in the cross-sectional observation image using a scanning electron microscope, the layer thicknesses of the A layer and the B layer in the normal direction of the reference line of the interface roughness between the substrate and the hard coating layer were measured, and the five layers of the hard coating layer were measured. By performing the same measurement and averaging the measured values, the average layer thickness of each A layer and B layer was calculated.
Tables 4 and 5 show the measured and calculated values.
さらに、本発明１〜１８および比較例工具１〜１８のＢ層について、走査型電子顕微鏡（ＳＥＭ）、透過型電子顕微鏡（ＴＥＭ）およびエネルギー分散型Ｘ線分析法（ＥＤＳ）を用いた層厚方向に沿った測定により、Ｃｒ最高含有点におけるＣｒ濃度ａｍａｘの値、Ｃｒ最低含有点におけるＣｒ濃度ａｍｉｎの値、Ｃｒ最高含有点とＣｒ最低含有点の間隔を測定した。
なお、ａｍａｘの値、ａｍｉｎの値、Ｃｒ最高含有点とＣｒ最低含有点の間隔は、いずれも５個所以上で層厚方向に沿ったＥＤＳ測定を行い、各々の層の測定値の平均値として求めたものである。
表４、表５に、測定・算出したそれぞれの値を示す。
Furthermore, about the B layer of this invention 1-18 and comparative example tools 1-18, the layer thickness using a scanning electron microscope (SEM), a transmission electron microscope (TEM), and energy dispersive X-ray-analysis (EDS) By the measurement along the direction, the value of Cr concentration amax at the highest Cr content point, the value of Cr concentration amin at the lowest Cr content point, and the interval between the highest Cr content point and the lowest Cr content point were measured.
The amax value, the amin value, and the interval between the highest Cr content point and the lowest Cr content point are 5 or more, and EDS measurement is performed along the layer thickness direction, and the average value of the measured values of each layer is used. It is what I have sought.
Tables 4 and 5 show the measured and calculated values.
次いで、本発明工具１〜１８および比較例工具１〜１８について、以下の条件で切削加工試験を実施した。
切削条件
被削材：ＪＩＳ・ＳＣｒ４２０（６０ＨＲＣ）の長さ方向等間隔８本縦溝入り丸棒、
切削速度：２１０ｍ／ｍｉｎ．、
切り込み：０．０５ｍｍ、
送り：０．１０ｍｍ／ｒｅｖ．、
切削時間：１５分、
の条件でのクロム鋼の乾式強断続切削加工試験を行い、切刃の逃げ面摩耗幅を測定し、また、チッピング発生の有無を観察した。
表６に、試験結果を示す。
Next, cutting tests were performed on the inventive tools 1 to 18 and the comparative tools 1 to 18 under the following conditions.
Cutting conditions Workpiece material: JIS · SCr420 (60HRC) lengthwise equal 8 round bars with longitudinal grooves,
Cutting speed: 210 m / min. ,
Cutting depth: 0.05mm,
Feed: 0.10 mm / rev. ,
Cutting time: 15 minutes,
The chrome steel was subjected to a dry strong interrupted cutting test under the above conditions, the flank wear width of the cutting edge was measured, and the presence or absence of chipping was observed.
Table 6 shows the test results.
表６に示される結果から、本発明の被覆工具は、硬質被覆層が（Ｔｉ，Ａｌ）Ｎ層からなるＡ層と（Ａｌ，Ｃｒ，Ｓｉ，Ｃｕ）Ｎ層からなるＢ層の二層構造または交互積層構造として構成され、さらに、二層構造のＢ層が、組成変調構造を有する層として構成されることによって、硬質被覆層が靭性と耐摩耗性の両特性を兼ね備えるため、焼入れ鋼などの高硬度鋼の強断続切削加工において、すぐれた耐クラック性と耐摩耗性を示し、長期の使用にわたってすぐれた切削性能を発揮するものである。 From the results shown in Table 6, the coated tool of the present invention has a two-layer structure in which the hard coating layer is an A layer composed of a (Ti, Al) N layer and a B layer composed of an (Al, Cr, Si, Cu) N layer. Alternatively, it is configured as an alternating layered structure, and further, since the B layer having a two-layer structure is configured as a layer having a composition modulation structure, the hard coating layer has both characteristics of toughness and wear resistance. It exhibits excellent cracking resistance and wear resistance in strong interrupted cutting of high-hardness steel, and exhibits excellent cutting performance over a long period of use.
これに対して、表６に示される結果から、比較例の被覆工具は、本発明で定めた硬質被覆層の組成あるいは層構造から外れたものであるため、クラックの発生・伝播、あるいは、摩耗進行によって、比較的短時間で使用寿命に至ることが明らかである。 On the other hand, from the results shown in Table 6, since the coated tool of the comparative example deviates from the composition or layer structure of the hard coating layer defined in the present invention, crack generation / propagation or wear It is clear that the service life is reached in a relatively short time by progress.
この発明の被覆工具は、焼入れ鋼などの高硬度鋼の強断続切削加工に供した場合に、すぐれた耐クラック性とともに長期の使用に亘ってすぐれた耐摩耗性を発揮するものであるから、切削加工装置の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。 The coated tool of the present invention exhibits excellent wear resistance over a long period of use as well as excellent crack resistance when subjected to hard interrupted cutting of hardened steel such as hardened steel. It is possible to satisfactorily respond to the FA of cutting devices, labor saving and energy saving of cutting, and cost reduction.
Claims (1)
（ａ）前記硬質被覆層は、Ａ層とＢ層の二層構造または合計層数が３層以上のＡ層とＢ層の交互積層構造、かつ基材直上にＡ層、最表面にＢ層が存在しており、
（ｂ）前記Ａ層は、０．１〜３．０μｍの一層平均層厚を有し、
組成式：（Ｔｉ１−ｘＡｌｘ）Ｎで表した場合、
０．４≦ｘ≦０．７（ただし、ｘは原子比）を満足する平均組成を有し、
（ｃ）前記Ｂ層は、０．１〜３．０μｍの一層平均層厚を有し、
組成式：（Ａｌ１−ａ−ｂ−ｃＣｒａＳｉｂＣｕｃ）Ｎで表した場合、
０．１５≦ａ≦０．４０、０．０５≦ｂ≦０．２０、０．００５≦ｃ≦０．０５（ただし、ａ、ｂ、ｃはいずれも原子比）を満足する平均組成を有し、かつ、
（ｄ）前記Ｂ層は、層厚方向に沿ってＣｒ成分濃度が周期的に変化する組成変調構造を有し、
（ｅ）前記組成変調構造におけるＣｒ成分濃度の周期的な変化は、Ｃｒ成分の最高含有点とＣｒ成分の最低含有点が１ｎｍ〜１００ｎｍの間隔で繰り返され、
（ｆ）前記Ｃｒ成分の最高含有点におけるＣｒ成分の組成の極大値をａｍａｘとしたとき、
ａ＜ａｍａｘ≦１．３ａの範囲内であり、
（ｇ）前記Ｃｒ成分の最低含有点におけるＣｒ成分の組成の極小値をａｍｉｎとしたとき、
０．７ａ≦ａｍｉｎ＜ａの範囲内である、
ことを特徴とする表面被覆切削工具。
In a surface-coated cutting tool in which a hard coating layer having a total average layer thickness of 0.5 to 4.0 μm is provided on the surface of a tool base made of a cubic boron nitride sintered body,
(A) The hard coating layer has a two-layer structure of an A layer and a B layer, or an alternately laminated structure of an A layer and a B layer having a total number of three or more layers, and an A layer directly on the substrate and a B layer on the outermost surface. Exists,
(B) The A layer has an average layer thickness of 0.1 to 3.0 μm,
When represented by a composition formula: (Ti 1-x Al x ) N,
Having an average composition satisfying 0.4 ≦ x ≦ 0.7 (where x is an atomic ratio),
(C) The B layer has an average layer thickness of 0.1 to 3.0 μm,
When represented by a composition formula: (Al 1-a-b-C c a Si b Cu c ) N,
It has an average composition satisfying 0.15 ≦ a ≦ 0.40, 0.05 ≦ b ≦ 0.20, 0.005 ≦ c ≦ 0.05 (wherein a, b, and c are atomic ratios). And
(D) The B layer has a composition modulation structure in which the Cr component concentration periodically changes along the layer thickness direction,
(E) The periodic change of the Cr component concentration in the composition modulation structure is repeated at intervals of 1 nm to 100 nm between the highest content point of the Cr component and the lowest content point of the Cr component,
(F) When the maximum value of the composition of the Cr component at the highest content point of the Cr component is amax,
a <amax ≦ 1.3a,
(G) When the minimum value of the composition of the Cr component at the minimum content point of the Cr component is amin,
0.7a ≦ amin <a.
A surface-coated cutting tool characterized by that.
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| WO2018221355A1 (en) * | 2017-05-30 | 2018-12-06 | 京セラ株式会社 | Coated tool and cutting tool provided with same |
| WO2020039736A1 (en) * | 2018-08-24 | 2020-02-27 | 住友電工ハードメタル株式会社 | Cutting tool |
| WO2020039735A1 (en) * | 2018-08-24 | 2020-02-27 | 住友電工ハードメタル株式会社 | Cutting tool |
| CN111005002A (en) * | 2020-01-08 | 2020-04-14 | 中国航空制造技术研究院 | Preparation method of erosion-resistant and corrosion-resistant self-cleaning coating for compressor blade |
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| WO2018221355A1 (en) * | 2017-05-30 | 2018-12-06 | 京セラ株式会社 | Coated tool and cutting tool provided with same |
| US11192189B2 (en) | 2017-05-30 | 2021-12-07 | Kyocera Corporation | Coated tool and cutting tool including same |
| CN112262006A (en) * | 2018-08-24 | 2021-01-22 | 住友电工硬质合金株式会社 | Cutting tool |
| JPWO2020039736A1 (en) * | 2018-08-24 | 2020-08-27 | 住友電工ハードメタル株式会社 | Cutting tools |
| CN112262007A (en) * | 2018-08-24 | 2021-01-22 | 住友电工硬质合金株式会社 | Cutting tool |
| WO2020039735A1 (en) * | 2018-08-24 | 2020-02-27 | 住友電工ハードメタル株式会社 | Cutting tool |
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| WO2020039736A1 (en) * | 2018-08-24 | 2020-02-27 | 住友電工ハードメタル株式会社 | Cutting tool |
| EP3842170A4 (en) * | 2018-08-24 | 2021-12-15 | Sumitomo Electric Hardmetal Corp. | Cutting tool |
| EP3842169A4 (en) * | 2018-08-24 | 2021-12-15 | Sumitomo Electric Hardmetal Corp. | Cutting tool |
| US11524339B2 (en) | 2018-08-24 | 2022-12-13 | Sumitomo Electric Hardmetal Corp. | Cutting tool |
| CN111005002A (en) * | 2020-01-08 | 2020-04-14 | 中国航空制造技术研究院 | Preparation method of erosion-resistant and corrosion-resistant self-cleaning coating for compressor blade |
| CN111005002B (en) * | 2020-01-08 | 2021-10-29 | 中国航空制造技术研究院 | Preparation method of erosion-resistant and corrosion-resistant self-cleaning coating for compressor blade |
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