JP2012066341A - Cutting tool made of surface-coated cubic boron nitride-based ultra-high-pressure sintered material - Google Patents
Cutting tool made of surface-coated cubic boron nitride-based ultra-high-pressure sintered material Download PDFInfo
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Abstract
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本発明は、鋳鉄や焼結合金はパーライト相とフェライト相などが析出するが、特にフェライト相が多く析出したダクタイル鋳鉄や焼結合金などを高速連続切削加工及び断続切削加工した場合でも、硬質被覆層がすぐれた潤滑性、耐溶着性を発揮し、長期にわたって安定した切削性能を発揮することができる、立方晶窒化ほう素基超高圧焼結材料で構成された切削工具基体（以下、工具基体という）の表面に硬質被覆層を形成した表面被覆立方晶窒化ほう素基超高圧焼結材料製切削工具（以下、被覆ｃＢＮ基焼結工具という）に関するものである。 In the present invention, pearlite and ferrite phases are precipitated in cast iron and sintered alloys, but even when ductile cast iron and sintered alloys in which a large amount of ferrite phases are precipitated are subjected to high-speed continuous cutting and intermittent cutting, they are hard-coated. Cutting tool base (hereinafter referred to as tool base) composed of cubic boron nitride based ultra-high pressure sintered material that has excellent lubricity and welding resistance, and stable cutting performance over a long period of time. And a cutting tool made of a surface-coated cubic boron nitride-based ultra-high pressure sintered material (hereinafter referred to as a coated cBN-based sintered tool).
一般に、被覆ｃＢＮ基焼結工具には、各種の鋼や鋳鉄などの被削材の旋削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インサートや、前記インサートを着脱自在に取り付けて、面削加工や溝加工、さらに肩加工などに用いられるソリッドタイプのエンドミルと同様に切削加工を行うインサート式エンドミルなどが知られている。 In general, a coated cBN-based sintered tool has an insert that can be attached to the tip of a cutting tool for turning of a work material such as various types of steel and cast iron, An insert-type end mill that performs cutting work in the same manner as a solid type end mill used for machining, grooving, and shoulder machining is known.
また、被覆ｃＢＮ基焼結工具としては、各種の立方晶窒化ほう素基超高圧焼結材料で構成された工具本体の表面に、チタンとアルミニウムの複合窒化物（ＴｉＡｌＮで示す）層などの表面被覆層を蒸着形成してなる被覆ｃＢＮ基焼結工具が知られており、これらが例えば各種の鋼や鋳鉄などの切削加工に用いられていることも知られている。 Further, as a coated cBN-based sintered tool, a surface of a composite body of titanium and aluminum (indicated by TiAlN) or the like on the surface of a tool body made of various cubic boron nitride-based ultrahigh pressure sintered materials Coated cBN-based sintered tools formed by vapor-depositing a coating layer are known, and it is also known that these are used for cutting of various steels and cast irons, for example.
さらに、前記被覆ｃＢＮ基焼結工具が、例えば、図１に概略説明図で示される物理蒸着装置の１種であるアークイオンプレーティング装置に前記工具基体を装入し、ヒーターで装置内を、例えば、５００℃に加熱した状態で、Ｔｉ−Ａｌ合金からなるカソード電極（蒸発源）と、アノード電極との間に、例えば、９０Ａの電流を印加してアーク放電を発生させ、同時に装置内に、例えば、反応ガスとして窒素ガスを導入して、例えば、２Ｐａの反応雰囲気とし、一方、前記工具基体には、例えば、−１００Ｖのバイアス電圧を印加した条件で、前記工具基体の表面に、ＴｉＡｌＮ層など、所望の層を蒸着形成することにより製造されることも知られている。 Furthermore, the coated cBN-based sintered tool is, for example, charged in the tool base in an arc ion plating apparatus which is a kind of physical vapor deposition apparatus schematically shown in FIG. For example, an arc discharge is generated by applying a current of 90 A, for example, between a cathode electrode (evaporation source) made of a Ti—Al alloy and an anode electrode while being heated to 500 ° C. For example, nitrogen gas is introduced as a reaction gas to form a reaction atmosphere of 2 Pa, for example. On the other hand, a TiAlN is applied to the surface of the tool base under a condition that a bias voltage of, for example, −100 V is applied to the tool base. It is also known to be produced by vapor deposition of a desired layer, such as a layer.
近年の切削加工装置のＦＡ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、通常の切削条件に加えて、より高速条件下での切削加工が要求される傾向にあるが、前記従来被覆工具においては、各種の鋼や鋳鉄を通常条件下で切削加工した場合に特段の問題は生じないが、これを、ダクタイル鋳鉄や焼結合金などのフェライト相が多く析出した被削材の高速連続切削及び断続切削に用いた場合には、切削時の高熱発生、高負荷による硬質被覆層の付着強度の不足のため、あるいは、溶着等の発生によって、比較的短時間で使用寿命に至るのが現状である。 In recent years, FA has been remarkable for cutting devices, but on the other hand, there is a strong demand for labor saving and energy saving and further cost reduction for cutting, and accordingly, cutting is performed at higher speed conditions in addition to normal cutting conditions. However, in the conventional coated tool, there is no particular problem when various types of steel and cast iron are machined under normal conditions. When used for high-speed continuous cutting and intermittent cutting of work materials in which a large amount of ferrite phase such as sintered alloy is precipitated, high heat generation during cutting, due to insufficient adhesion strength of the hard coating layer due to high load, or At present, the service life is reached in a relatively short time due to the occurrence of welding or the like.
そこで、本発明者らは、前述のような観点から、ダクタイル鋳鉄や焼結合金などのフェライト相が多く析出した被削材の高速連続切削加工及び断続切削加工で、硬質被覆層がすぐれた付着強度を備えるとともにすぐれた潤滑性、耐溶着性を発揮し、長期の使用に亘って、すぐれた切削性能を発揮する被覆ｃＢＮ基焼結工具を開発すべく研究を行った結果、次のような知見を得た。 In view of the above, the present inventors, from the above-mentioned viewpoint, have excellent adhesion of the hard coating layer in high-speed continuous cutting and intermittent cutting of a work material in which a large amount of ferrite phase such as ductile cast iron and sintered alloy is precipitated. As a result of research to develop a coated cBN-based sintered tool that has strength and exhibits excellent lubricity and welding resistance, and exhibits excellent cutting performance over a long period of use. Obtained knowledge.
（ａ）超高圧焼結材料製工具基体中の立方晶窒化ほう素（以下、ｃＢＮで示す）は、きわめて硬質で、焼結材料中で分散相を形成し、そしてこの分散相によって耐摩耗性の向上を図ることができるが、ｃＢＮの配合割合が、例えば、７０容量％以上というように多くなったような場合には、工具基体の硬さ上昇は見込めるものの、耐摩耗性が低下し、さらに、ＴｉＡｌＮ層からなる硬質被覆層との付着強度が低下傾向を示すようになるため、高熱発生を伴うとともに、切刃に対して高負荷が作用する高硬度材の高速連続切削加工及び断続切削加工においては、硬質被覆層の欠損、剥離の発生によって、工具基体の有するすぐれた高温硬さを切削性能向上に生かすことができない。 (A) Cubic boron nitride (hereinafter referred to as cBN) in a tool base made of ultra-high pressure sintered material is extremely hard, forms a dispersed phase in the sintered material, and wear resistance is obtained by this dispersed phase. However, when the blending ratio of cBN is increased to, for example, 70% by volume or more, although the hardness of the tool base can be expected to increase, the wear resistance decreases, Furthermore, since the adhesion strength with the hard coating layer made of a TiAlN layer tends to decrease, high-speed continuous cutting and intermittent cutting of a hard material with high heat generation and high load acting on the cutting blade. In machining, the high-temperature hardness of the tool base cannot be used to improve cutting performance due to the occurrence of chipping or peeling of the hard coating layer.
（ｂ）そこで、工具基体とＴｉＡｌＮ層の付着強度を改善する硬質被覆層構造について、数多くの実験を重ねた結果、硬質被覆層を、下部層、中間層および上部層の三層構造として構成し、さらに、下部層は、ＴｉＢ２層、中間層は、ＴｉＢ２相とＴｉＮ相との２相混合組織からなる層（以下、ＴｉＢ２−ＴｉＮ混合層で示す）、上部層は、ＴｉＡｌＮ層で形成した場合には、層間付着強度が高いため、その結果、下部層および中間層を介したことにより、工具基体とＴｉＡｌＮ層の付着強度が大幅に改善されることを見出した。 (B) Therefore, as a result of many experiments conducted on the hard coating layer structure that improves the adhesion strength between the tool base and the TiAlN layer, the hard coating layer is configured as a three-layer structure of a lower layer, an intermediate layer, and an upper layer. Furthermore, the lower layer is a TiB 2 layer, the intermediate layer is a layer composed of a two-phase mixed structure of a TiB 2 phase and a TiN phase (hereinafter referred to as a TiB 2 -TiN mixed layer), and the upper layer is a TiAlN layer. When formed, the interlayer adhesion strength is high, and as a result, it has been found that the adhesion strength between the tool base and the TiAlN layer is greatly improved through the lower layer and the intermediate layer.
（ｃ）さらに、中間層のＴｉＢ２−ＴｉＮ混合層について、下部層側ではＴｉＢ２の含有比率を高くしＴｉＮの含有比率を下げ、逆に、上部層側ではＴｉＢ２の含有比率を下げＴｉＮ含有比率を高める傾斜組織構造を採用することにより、より一層、下部層−中間層、また、中間層−上部層間での層間付着強度が高くなることから、硬質被覆層間の付着強度がより一段と高くなることを見出したのである。 (C) In addition, the TiB 2-TiN mixed layer of the intermediate layer, the lower layer side to increase the content ratio of TiB 2 lowers the content of TiN, conversely, TiN lower the content of TiB 2 in the upper layer side By adopting the gradient structure that increases the content ratio, the interlayer adhesion strength between the lower layer-intermediate layer and between the intermediate layer and the upper layer is further increased, so that the adhesion strength between the hard coating layers is further increased. I found out.
（ｄ）したがって、ｃＢＮ含有量が、例えば、７０容量％以上というように多い被覆ｃＢＮ基焼結工具において、ＴｉＢ２層からなる下部層、傾斜組織構造のＴｉＢ２−ＴｉＮ混合層からなる中間層、ＴｉＡｌＮ層からなる上部層で硬質被覆層を構成した場合には、各層間の付着強度が高くなることに加えて、工具基体と硬質被覆層を合わせた強度の点でも高くなることから、硬質被覆層は全体として、すぐれた高温硬さ、靭性、高温強度を備え、その結果、大きな発熱と高負荷を伴うダクタイル鋳鉄や焼結合金などのフェライト相が多く析出した被削材の高速連続切削加工及び断続切削加工において、欠損、剥離等を生じることなく、長期の使用に亘ってすぐれた耐摩耗性と耐欠損性を示し、安定した切削性能を発揮するものである。 (D) Therefore, cBN content, for example, in many surface-coated cBN-based sintered tool as of 70 volume percent or more, lower layer composed of TiB 2 layer, an intermediate layer made of TiB 2-TiN mixed layers of mound organizational structure When the hard coating layer is composed of the upper layer made of the TiAlN layer, the adhesion strength between the layers is increased, and the strength of the tool base and the hard coating layer is also increased. The coating layer as a whole has excellent high-temperature hardness, toughness, and high-temperature strength, and as a result, high-speed continuous cutting of work materials in which a large amount of ferrite phase such as ductile iron or sintered alloy with large heat generation and high load is deposited. In machining and intermittent cutting, it exhibits excellent wear resistance and fracture resistance over a long period of time without causing defects, peeling, etc., and exhibits stable cutting performance.
（ｅ）また、ＴｉＡｌＮ層は、耐摩耗性にすぐれるが、耐溶着性に劣る。そのため、逃げ面にコーティングすることは、耐摩耗性の向上に繋がるが、切屑と接触するすくい面、ホーニング面では溶着が起こり、膜の剥離や摩耗が大きく、チッピング、欠損の原因となる。そこで、すくい面、ホーニング面に耐溶着性に優れたＴｉＢ２−ＴｉＮ混合層を露出させることによって、溶着が起こりにくく、耐クレータ磨耗性が向上し、また、逃げ面には耐磨耗性にすぐれたＴｉＡｌＮを上部層に残すことで、長期の使用に亘って、すぐれた耐摩耗性と耐欠損性を示し、安定した切削性能を発揮する。すなわち、すくい面、ホーニング面の上部層であるＴｉＡｌＮ層を除去して中間層のＴｉＢ２−ＴｉＮ混合層を露出させることにより、ＴｉＢ２−ＴｉＮ混合層のすぐれた潤滑性、耐溶着性が発揮され、ダクタイル鋳鉄や焼結合金などのフェライト相が多く析出した被削材の高速連続切削加工及び断続切削加工を行った場合においても、溶着が起こりにくく、耐クレータ磨耗性が向上し、長期の使用に亘ってすぐれた耐摩耗性と耐欠損性を示し、安定した切削性能を発揮するものである。 (E) In addition, the TiAlN layer has excellent wear resistance but is inferior in welding resistance. For this reason, coating the flank surface leads to improved wear resistance, but welding occurs on the rake surface and honing surface that come into contact with the chips, resulting in large film peeling and wear, leading to chipping and chipping. Therefore, by exposing the TiB2-TiN mixed layer with excellent welding resistance on the rake face and honing surface, welding is less likely to occur, crater wear resistance is improved, and the flank face has excellent wear resistance. By leaving TiAlN in the upper layer, it exhibits excellent wear resistance and fracture resistance over a long period of use, and exhibits stable cutting performance. That is, by removing the TiAlN layer, which is the upper layer of the rake face and honing face, and exposing the TiB 2 -TiN mixed layer as an intermediate layer, the excellent lubricity and welding resistance of the TiB 2 -TiN mixed layer are exhibited. Even when high-speed continuous cutting and intermittent cutting of a work material with a large amount of ferrite phase precipitated, such as ductile cast iron and sintered alloy, welding is less likely to occur, crater wear resistance is improved, and long-term It exhibits excellent wear resistance and fracture resistance over use, and exhibits stable cutting performance.
本発明は、前記知見に基づいてなされたものであって、
「（１） 立方晶窒化ほう素基超高圧焼結材料を母材とする工具本体のすくい面と逃面との交差稜線部にホーニングを施した切刃部が形成されているとともに、前記工具本体の表面に、該工具本体側から順に下部層、中間層および上部層からなる硬質被覆層を蒸着形成した表面被覆立方晶窒化ほう素基超高圧焼結材料製切削工具において、
（ａ）前記下部層は、０．０５〜０．５μｍの層厚を有するＴｉＢ２層、
（ｂ）前記中間層は、０．３〜１μｍの層厚を有し、
組成式：Ｔｉ１−Ｘ−ＹＢＸＮＹ
で表した場合、０．１５≦Ｘ≦０．６０、０．０５≦Ｙ≦０．３５、０．５０≦Ｘ＋Ｙ≦０．６５（但し、Ｘ、Ｙはいずれも原子比）を満足する平均組成を有し、さらに、下部層側から上部層側へ向うにしたがって、Ｘの値は次第に減少し、Ｙの値は次第に増加する傾斜組織構造を有するＴｉＢ２相とＴｉＮ相との２相混合層、
（ｃ）前記上部層は、０．５〜５μｍの層厚を有し、
組成式：（Ｔｉ１−ＺＡｌＺ）Ｎ層
で表した場合、Ｚが０．３〜０．６５（但し、Ｚは原子比）であるＴｉとＡｌの複合窒化物層、
であるとともに、
（ｄ）前記工具本体のすくい面とホーニング面は、前記上部層が除去されることにより中間層が主として露出していることを特徴とする表面被覆立方晶窒化ほう素基超高圧焼結材料製切削工具。
（２） 前記立方晶窒化ほう素基超高圧焼結材料の立方晶窒化ほう素の含有量が７０容量％以上であることを特徴とする（１）記載の表面被覆立方晶窒化ほう素基超高圧焼結材料製切削工具。」
に特徴を有するものである。
The present invention has been made based on the above findings,
“(1) A cutting edge portion formed by honing a cross ridge line portion between a rake face and a relief face of a tool body using a cubic boron nitride-based ultrahigh pressure sintered material as a base material, and the tool In the surface-coated cubic boron nitride-based ultra-high pressure sintered material cutting tool in which a hard coating layer consisting of a lower layer, an intermediate layer and an upper layer is deposited in this order from the tool body side on the surface of the main body,
(A) The lower layer is a TiB 2 layer having a layer thickness of 0.05 to 0.5 μm,
(B) the intermediate layer has a layer thickness of 0.3-1 μm;
Composition formula: Ti 1-XY B X N Y
In this case, an average satisfying 0.15 ≦ X ≦ 0.60, 0.05 ≦ Y ≦ 0.35, 0.50 ≦ X + Y ≦ 0.65 (where X and Y are atomic ratios) Two-phase mixing of TiB 2 phase and TiN phase having a gradient structure in which the value of X gradually decreases and the value of Y gradually increases as it moves from the lower layer side to the upper layer side. layer,
(C) the upper layer has a layer thickness of 0.5-5 μm;
Composition formula: (Ti 1-Z Al Z ) When represented by an N layer, a composite nitride layer of Ti and Al in which Z is 0.3 to 0.65 (where Z is an atomic ratio),
And
(D) The rake face and the honing face of the tool body are made of a surface-coated cubic boron nitride-based ultrahigh pressure sintered material, wherein the intermediate layer is mainly exposed by removing the upper layer. Cutting tools.
(2) The surface-coated cubic boron nitride-based superstructure according to (1), wherein the cubic boron nitride-based ultra-high pressure sintered material has a cubic boron nitride content of 70% by volume or more. Cutting tool made of high pressure sintered material. "
It has the characteristics.
つぎに、本発明の被覆ｃＢＮ基焼結工具の硬質被覆層を構成する各層について説明する。 Next, each layer constituting the hard coating layer of the coated cBN-based sintered tool of the present invention will be described.
下部層：
下部層を構成するＴｉＢ２層は、高温での安定性にすぐれ、かつ、硬さも高く、工具基体および中間層を構成するＴｉＢ２−ＴｉＮ混合層のいずれに対してもすぐれた密着性を有し、工具基体と硬質被覆層の付着強度の向上に寄与する。
さらに、下部層のＴｉＢ２のヤング率は、工具基体の主成分であるｃＢＮ相のそれに近く、刃先に大きな応力が作用する重切削に用いた場合でも、下部層と工具基体の変形挙動の差が小さく、下部層の剥離や破壊が生じにくいため、結果として安定した刃先を長期に亘って維持することができる。
ＴｉＢ２層は、ターゲットにＴｉＢ２焼結体を使用し、Ａｒガス雰囲気中で高周波スパッタリングを行うことにより形成することができる。
ＴｉＢ２層の層厚は、０．０５μｍ未満では、密着層としての効果が十分でなく、一方、その層厚が０．５μｍを超えると、膜全体としての強度が低下し、高負荷での切削時に破壊が生じやすくなることから、ＴｉＢ２層の層厚は、０．０５〜０．５μｍと定めた。
Lower layer:
The TiB 2 layer constituting the lower layer is excellent in stability at high temperatures, has high hardness, and has excellent adhesion to both the tool base and the TiB 2 -TiN mixed layer constituting the intermediate layer. In addition, this contributes to an improvement in the adhesion strength between the tool base and the hard coating layer.
Furthermore, the Young's modulus of TiB 2 in the lower layer is close to that of the cBN phase, which is the main component of the tool base, and even when used for heavy cutting in which a large stress acts on the cutting edge, the difference in deformation behavior between the lower layer and the tool base. Is small, and peeling and destruction of the lower layer hardly occur. As a result, a stable cutting edge can be maintained for a long period of time.
The TiB 2 layer can be formed by using a TiB 2 sintered body as a target and performing high-frequency sputtering in an Ar gas atmosphere.
If the layer thickness of the TiB 2 layer is less than 0.05 μm, the effect as an adhesion layer is not sufficient, while if the layer thickness exceeds 0.5 μm, the strength of the entire film is reduced and the load is high. Since the breakage is likely to occur during cutting, the thickness of the TiB 2 layer is set to 0.05 to 0.5 μm.
中間層：
中間層を構成するＴｉＢ２−ＴｉＮ混合層を、
Ｔｉ１−Ｘ−ＹＢＸＮＹ
で表した場合、Ｘは０．１５〜０．６０、Ｙは０．０５〜０．３５、Ｘ＋Ｙは０．５０〜０．６５（但し、Ｘ、Ｙはいずれも原子比）を満足する平均組成を有し、さらに、下部層側から上部層側へ向うにしたがって、Ｘの値は次第に減少し、Ｙの値は次第に増加する傾斜組織構造を形成するように、中間層中のＴｉＢ２含有割合およびＴｉＮ含有割合を調整する。
前記組成式において、Ｘ、ＹおよびＸ＋Ｙを、それぞれ、０．１５〜０．６０、０．０５〜０．３５および０．５０〜０．６５（但し、Ｘ、Ｙのいずれも原子比）を満足ように定めた理由は、以下のとおりである。
Ｂの含有割合Ｘが０．６０を超える場合、あるいは、Ｎの含有割合Ｙが０．０５を下回る場合には、上部層のＴｉＡｌＮ層との密着強度が十分でなく、層間での剥離が生じやすくなり、逆に、Ｂの含有割合Ｘが０．１５を下回る場合、あるいは、Ｎの含有割合Ｙが０．３５を超える場合には、下部層のＴｉＢ２層と所定の密着性が得られなくなり、同様に層間での剥離が生じやすくなる。また、ＢとＮの合計含有割合Ｘ＋Ｙが０．６５を超えると、相対的にＮの含有割合が減少し、実質的にＴｉＢ２相の量が大部分を占めるようになることを意味し、上部層ＴｉＡｌＮ層との密着強度が十分でなくなる。
また、Ｘ＋Ｙが０．５０を下回る場合には、ＴｉＢ２相とＴｉＮ相の２相混合層を形成することが困難となり、特に、下部層との密着強度が得られなくなる。
したがって、ＴｉＢ２−ＴｉＮ混合層の平均組成を示すＢの含有割合Ｘ、Ｎの含有割合ＹおよびＢとＮの合計含有割合Ｘ＋Ｙを、それぞれ、０．１５〜０．６０、０．０５〜０．３５および０．５０〜０．６５と定めた。
さらに、下部層および上部層との密着性、付着強度を高めるために、下部層側では、相対的にＴｉＢ２の含有比率を高くしＴｉＮの含有比率を下げ、逆に、上部層側では、相対的にＴｉＢ２の含有比率を下げＴｉＮ含有比率を高める組織傾斜構造を有するＴｉＢ２−ＴｉＮ混合層を形成することが必要である。ＴｉＢ２の含有比率が高くＴｉＮの含有比率が低い下部層側のＴｉＢ２−ＴｉＮ混合層、および、ＴｉＢ２の含有比率が低くＴｉＮの含有比率が高い上部層側のＴｉＢ２−ＴｉＮ混合層は、それぞれ、下部層および上部層と類似する成分、組成の界面を形成するため、密着性、付着強度がより一層高められる。
Middle layer:
The TiB 2 -TiN mixed layer constituting the intermediate layer,
Ti 1-XY B X N Y
X is 0.15 to 0.60, Y is 0.05 to 0.35, and X + Y is 0.50 to 0.65 (where X and Y are both atomic ratios). The composition further includes TiB 2 in the intermediate layer so as to form a graded structure in which the value of X gradually decreases and the value of Y gradually increases from the lower layer side to the upper layer side. Adjust the ratio and TiN content ratio.
In the composition formula, X, Y, and X + Y are 0.15 to 0.60, 0.05 to 0.35, and 0.50 to 0.65 (wherein X and Y are atomic ratios), respectively. The reasons for satisfying are as follows.
When the content ratio X of B exceeds 0.60, or when the content ratio Y of N is less than 0.05, the adhesion strength between the upper layer and the TiAlN layer is not sufficient, and peeling between layers occurs. On the contrary, when the B content ratio X is less than 0.15, or when the N content ratio Y exceeds 0.35, predetermined adhesion with the TiB 2 layer of the lower layer is obtained. Similarly, peeling between layers is likely to occur. Further, when the total content ratio X + Y of B and N exceeds 0.65, it means that the content ratio of N is relatively decreased, and the amount of TiB 2 phase is substantially occupied, Adhesion strength with the upper TiAlN layer becomes insufficient.
Moreover, when X + Y is less than 0.50, it becomes difficult to form a two-phase mixed layer of TiB 2 phase and TiN phase, and in particular, adhesion strength with the lower layer cannot be obtained.
Therefore, the content ratio X of B indicating the average composition of the TiB 2 -TiN mixed layer, the content ratio Y of N, and the total content ratio X + Y of B and N are 0.15 to 0.60 and 0.05 to 0, respectively. .35 and 0.50 to 0.65.
Furthermore, in order to increase the adhesion and adhesion strength between the lower layer and the upper layer, on the lower layer side, the content ratio of TiB 2 is relatively increased and the content ratio of TiN is lowered, and conversely, on the upper layer side, It is necessary to form a TiB 2 —TiN mixed layer having a textured gradient structure that relatively lowers the TiB 2 content ratio and increases the TiN content ratio. The TiB 2 -TiN mixed layer on the lower layer side with a high TiB 2 content ratio and a low TiN content ratio, and the TiB 2 -TiN mixed layer on the upper layer side with a low TiB 2 content ratio and a high TiN content ratio are Since the interfaces of components and compositions similar to those of the lower layer and the upper layer are formed, respectively, adhesion and adhesion strength are further improved.
ＴｉＢ２−ＴｉＮ混合層は、ターゲットにＴｉＢ２焼結体と金属チタンの２種類を使用し、Ａｒガスと窒素ガスの混合雰囲気中で高周波スパッタリングを行うことにより形成することができる。ただ、ＴｉＢ２−ＴｉＮ混合層中に傾斜組織構造を構成するために、スパッタリングによる成膜初期には、雰囲気ガス中の窒素ガス含有割合および金属チタンターゲットへの供給電力を小さくしておき、成膜の進行に伴って、雰囲気ガス中の窒素ガス含有割合および金属チタンターゲットへの電力を順次高めていくことが必要である。
また、形成するＴｉＢ２−ＴｉＮ混合層の層厚が０．３μｍ未満では、密着層としての効果が十分でなく、一方、その層厚が１μｍを超えると、膜全体としての強度が低下し、高負荷での切削時に破壊が生じやすくなることから、ＴｉＢ２−ＴｉＮ混合層の層厚は、０．３〜１μｍと定めた。
The TiB 2 -TiN mixed layer can be formed by using high frequency sputtering in a mixed atmosphere of Ar gas and nitrogen gas, using two types of TiB 2 sintered bodies and titanium metal as targets. However, in order to form a tilted structure in the TiB 2 -TiN mixed layer, at the initial stage of film formation by sputtering, the nitrogen gas content ratio in the atmospheric gas and the power supplied to the titanium metal target are reduced, and the formation is completed. As the film progresses, it is necessary to sequentially increase the nitrogen gas content in the atmospheric gas and the power to the metal titanium target.
In addition, when the layer thickness of the TiB 2 -TiN mixed layer to be formed is less than 0.3 μm, the effect as the adhesion layer is not sufficient, while when the layer thickness exceeds 1 μm, the strength of the entire film is reduced, Since breakage is likely to occur during cutting under high load, the thickness of the TiB 2 -TiN mixed layer was determined to be 0.3 to 1 μm.
上部層：
ＴｉＡｌＮ層におけるＴｉ成分は高温強度の維持、Ａｌ成分は高温硬さと耐酸化性の向上に寄与することから、ＴｉＡｌＮ層は、所定の高温強度、高温硬さおよび耐熱性を具備する層であって、合金工具鋼や軸受け鋼の焼入れ材などの高硬度材からなる被削材の高速切削加工時における切刃部の耐摩耗性を確保する役割を基本的に担う。
ただ、上部層を構成するＴｉＡｌＮ層を、
組成式：（Ｔｉ１−ＺＡｌＺ）Ｎ
で表した場合に、Ａｌの含有割合Ｚが０．６５を超えると、結晶構造の変化により、高温強度が低下し欠損が生じやすくなり、一方、Ａｌの含有割合Ｚが０．３未満になると、高温硬さと耐熱性が低下し、その結果、耐摩耗性の低下がみられるようになることから、Ａｌの含有割合Ｚの値を０．３〜０．６５（但し、原子比）と定めた。
また、上部層を構成するＴｉＡｌＮ層は、被削材としてダクタイル鋳鉄や焼結合金などのフェライト相が多く析出した被削材を切削した場合には、溶着しやすいため、すくい面とホーニング面の上部層をウェットブラスト処理で除去し、潤滑性および耐溶着性にすぐれたＴｉＢ２−ＴｉＮ混合層を露出させる。
ＴｉＡｌＮ層からなる上部層は、例えば、アークイオンプレーティング法により成膜すればよいが、上部層の層厚が０．５μｍ未満では、自身のもつ耐熱性、高温硬さおよび高温強度を硬質被覆層に長期に亘って付与できず、工具寿命短命の原因となり、一方、その層厚が５μｍを越えると、欠損が生じ易くなることから、上部層の層厚は、０．５〜５μｍと定めた。
Upper layer:
Since the Ti component in the TiAlN layer maintains high temperature strength and the Al component contributes to improvement in high temperature hardness and oxidation resistance, the TiAlN layer is a layer having predetermined high temperature strength, high temperature hardness and heat resistance. Basically, it plays a role of ensuring the wear resistance of the cutting edge part during high-speed cutting of a work material made of a hard material such as a hardened material of alloy tool steel or bearing steel.
However, the TiAlN layer constituting the upper layer is
Formula: (Ti 1-Z Al Z ) N
In the case where the Al content ratio Z exceeds 0.65, the crystal structure changes and the high-temperature strength decreases and defects tend to occur. On the other hand, when the Al content ratio Z is less than 0.3, Since the high temperature hardness and heat resistance decrease, and as a result, the wear resistance decreases, the value of the Al content ratio Z is determined to be 0.3 to 0.65 (however, the atomic ratio). It was.
In addition, the TiAlN layer constituting the upper layer is easily welded when a work material with a large amount of ferrite phase precipitated such as ductile cast iron or sintered alloy is cut as the work material. The upper layer is removed by wet blasting to expose a TiB 2 -TiN mixed layer having excellent lubricity and welding resistance.
The upper layer made of a TiAlN layer may be formed by, for example, an arc ion plating method. However, if the thickness of the upper layer is less than 0.5 μm, the heat resistance, high-temperature hardness and high-temperature strength that it has are hard-coated. The layer cannot be applied to the layer for a long period of time, resulting in a short tool life. On the other hand, if the layer thickness exceeds 5 μm, defects tend to occur. Therefore, the layer thickness of the upper layer is determined to be 0.5 to 5 μm. It was.
本発明の被覆ｃＢＮ基焼結工具は、ｃＢＮの配合割合が好ましくは、７０容量％以上である工具基体表面に、下部層、中間層および上部層からなる硬質被覆層を形成し、かつ、下部層をＴｉＢ２層、中間層を特定組成の、かつ、傾斜組織構造を有するＴｉＢ２−ＴｉＮ混合層、また、上部層を特定組成のＴｉＡｌＮ層とするとともに、すくい面とホーニング面の上部層を除去して中間層を露出させることによって、特にすぐれた付着強度を有し、さらに、高温硬さ、靭性、耐衝撃性、潤滑性、耐溶着性を兼ね備えることから、ダクタイル鋳鉄や焼結合金などのフェライト相が多く析出した被削材の、高熱発生を伴い、かつ、切刃に高負荷が作用する高速連続切削及び断続切削条件下であっても、前記硬質被覆層に、剥離や溶着等の発生はなく、長期の使用に亘って、すぐれた耐摩耗性、耐欠損性を発揮することができる。 In the coated cBN-based sintered tool of the present invention, a hard coating layer composed of a lower layer, an intermediate layer, and an upper layer is formed on the surface of the tool base, in which the mixing ratio of cBN is preferably 70% by volume or more. The layer is a TiB 2 layer, the intermediate layer is a TiB 2 -TiN mixed layer having a specific composition and a graded structure, the upper layer is a TiAlN layer having a specific composition, and the upper layer of the rake face and the honing face By removing and exposing the intermediate layer, it has excellent adhesion strength, and also has high temperature hardness, toughness, impact resistance, lubricity, and welding resistance, so it can be used for ductile cast iron, sintered alloys, etc. Even if the work material with a large amount of ferrite phase precipitated is accompanied by high heat generation and high-speed continuous cutting and intermittent cutting conditions in which a high load acts on the cutting edge, peeling or welding to the hard coating layer, etc. Occurrence of , Over a long period of use, excellent wear resistance can be exhibited chipping resistance.
つぎに、本発明の被覆ｃＢＮ基焼結工具を実施例により具体的に説明する。 Next, the coated cBN-based sintered tool of the present invention will be specifically described with reference to examples.
原料粉末として、いずれも０．５〜４μｍの範囲内の平均粒径を有するｃＢＮ粉末、ＴｉＮ粉末、ＡｌＮ粉末、Ｎｉ粉末、Ａｌ粉末、Ｃｏ粉末、Ｗ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８０時間湿式混合し、乾燥した後、１２０ＭＰａの圧力で直径：５０ｍｍ×厚さ：１．５ｍｍの寸法をもった圧粉体にプレス成形し、ついでこの圧粉体を、圧力：１Ｐａの真空雰囲気中、９００〜１３００℃の範囲内の所定温度に６０分間保持の条件で焼結して切刃片用予備焼結体とし、この予備焼結体を、別途用意した、Ｃｏ：８質量％、ＷＣ：残りの組成、並びに直径：５０ｍｍ×厚さ：２ｍｍの寸法をもったＷＣ基超硬合金製支持片と重ね合わせた状態で、通常の超高圧焼結装置に装入し、通常の条件である圧力：４ＧＰａ、温度：１２００〜１４００℃の範囲内の所定温度に保持時間：０．８時間の条件で超高圧焼結し、焼結後上下面をダイヤモンド砥石を用いて研磨し、ワイヤー放電加工装置またはダイヤモンド切断機にて一辺３ｍｍの正三角形状に分割し、さらにＣｏ：５質量％、ＴａＣ：５質量％、ＷＣ：残りの組成およびＣＩＳ規格ＴＮＧＡ１６０４０８の形状（厚さ：４．７６mm×一辺長さ：１２．７mmの正方形）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％、Ｎｉ：２．５％、Ａｇ：残りからなる組成を有するＡｇ合金のろう材を用いてろう付けし、所定寸法に外周加工した後、切刃部に幅：０．１３ｍｍ、角度：２５°のホーニング加工を施し、さらに仕上げ研摩を施すことによりＩＳＯ規格ＴＮＧＡ１６０４０８のインサート形状をもった工具基体Ａ〜Ｊをそれぞれ製造した。 As the raw material powder, cBN powder, TiN powder, AlN powder, Ni powder, Al powder, Co powder, and W powder each having an average particle diameter in the range of 0.5 to 4 μm are prepared. The mixture is blended in the composition shown in FIG. 1, wet mixed with a ball mill for 80 hours, dried, and then pressed into a green compact having a diameter of 50 mm × thickness: 1.5 mm under a pressure of 120 MPa. The green compact is sintered in a vacuum atmosphere at a pressure of 1 Pa at a predetermined temperature within a range of 900 to 1300 ° C. for 60 minutes to obtain a presintered body for a cutting edge piece. In addition, Co: 8% by mass, WC: remaining composition, and diameter: 50 mm × thickness: 2 mm, superposed on a WC-based cemented carbide support piece with a normal super-high pressure Charged into the sintering machine and under normal conditions Force: 4 GPa, temperature: Presence at a predetermined temperature in the range of 1200-1400 ° C. Holding time: 0.8 hours under high pressure sintering, after sintering, the upper and lower surfaces are polished with a diamond grindstone, and wire electric discharge machining It is divided into equilateral triangles with a side of 3 mm by an apparatus or a diamond cutter, and further Co: 5 mass%, TaC: 5 mass%, WC: remaining composition and shape of CIS standard TNGA160408 (thickness: 4.76 mm × one side) Cu: 26%, Ti: 5%, Ni: 2.5% in the brazing part (corner part) of the WC-base cemented carbide insert body having a length of 12.7 mm square) , Ag: brazing using a brazing material of an Ag alloy having the remaining composition, and after processing the outer periphery to a predetermined dimension, the honing process is performed on the cutting edge portion with a width of 0.13 mm and an angle of 25 °. Finish polishing By applying, tool bases A to J having the insert shape of ISO standard TNGA160408 were manufactured.
ついで、前記工具基体Ａ〜Ｊのそれぞれを、アセトン中で超音波洗浄し、乾燥した状態で、図１に示されるアークイオンプレーティング（ＡＩＰ）装置とＲＦスパッタリング（ＲＦ−ＳＰ）装置を併設した蒸着装置内の回転テーブル上に外周部に沿って装着し、前記ＡＩＰ装置のカソード電極（蒸発源）として、所定の成分組成をもったＴｉ−Ａｌ合金、前記ＲＦ−ＳＰ装置のターゲット（蒸発源）として金属ＴｉおよびＴｉＢ２焼結体を装着し、
（ａ）まず装置内を排気して０．５Ｐａ以下の真空に保持しながら、ヒーターで装置内を４５０〜６００℃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−２００Ｖのパルスバイアス電圧を印加して、さらに２．０ＰａのＡｒ雰囲気として、もって工具基体表面をＡｒガスボンバード洗浄し、
（ｂ）ついで、装置内に反応ガスとして、アルゴンガスを導入して０．３Ｐａの反応雰囲気とすると共に、ＴｉＢ２焼結体のターゲットに高周波電源を用いて３００Ｗの高周波電力を印加してスパッタを行い、また、−２００Ｖのパルス電圧を印加することにより前記回転テーブル上で自転しながら回転する工具基体表面に目標層厚の下部層（ＴｉＢ２層）を形成し、
（ｃ）ついで、装置内に反応ガスとして、アルゴン−窒素混合ガスを導入し、スパッタの進行とともに、窒素含有割合を増加させるように調整しつつ、０．３Ｐａの反応雰囲気とすると共に、前記回転テーブル上で自転しながら回転する工具基体に−１００Ｖの直流バイアス電圧を印加して、ＴｉＢ２焼結体のターゲットに高周波電源を用いてスパッタを行うとともに、金属Ｔｉのターゲットに高周波電源を用いてスパッタを行い、それぞれの印加電力を目標組織となるように調整し、工具基体表面に目標層厚、目標傾斜組織の中間層（ＴｉＢ２−ＴｉＮ混合層）を形成し、
（ｄ）ついで、装置内に反応ガスとして窒素ガスを導入して２〜４Ｐａの反応雰囲気とすると共に、回転テーブル上で自転しながら回転する工具基体に−１０〜−５０Ｖのパルスバイアス電圧を印加し、前記Ｔｉ−Ａｌ合金からなる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、もって前記工具基体表面に、表２に示される目標組成および目標層厚をもったＴｉＡｌＮ層からなる上部層を蒸着することにより、
ＩＳＯ規格ＴＮＧＡ１６０４０８に規定するスローアウエイチップ形状の本発明被覆ｃＢＮ基焼結工具１〜１０（本発明工具１〜１０という）をそれぞれ製造した。
（ｅ）さらに、図２の断面図に示すように、スローアウエイチップ形状の本発明被覆ｃＢＮ基焼結工具のすくい面とホーニング面の上部層をウェットブラスト処理により除去し、中間層を露出させる。ウェットブラスト処理は、噴射研磨材を含有した液体（一般には水）である研磨液を被処理物に噴射して研磨を行なうものであり、弾性砥石やブラシを用いた機械加工はもとより、乾式のブラスト処理と比べても、液体が被処理物との間で噴射研磨材の運動エネルギーを減衰させるため、加工エネルギーの比較的弱いソフトな加工となる。このため、本発明のような最外層の除去に用いることにより、露出させられた中間層表面への研磨傷の発生も少なく抑えることができ、例えば、算術平均粗さＲａで０．１μｍ以下の表面粗さの平滑なすくい面およびホーニング面を形成することが可能となる。
最外層除去後の中間層の厚みは、０．３〜０．９μｍである。
Next, each of the tool bases A to J was ultrasonically cleaned in acetone and dried, and an arc ion plating (AIP) apparatus and an RF sputtering (RF-SP) apparatus shown in FIG. Attached along the outer periphery on a rotary table in a vapor deposition apparatus, and used as a cathode electrode (evaporation source) of the AIP apparatus, a Ti-Al alloy having a predetermined component composition, a target (evaporation source) of the RF-SP apparatus ) With metal Ti and TiB 2 sintered body,
(A) First, the inside of the apparatus is evacuated and kept at a vacuum of 0.5 Pa or less, and the inside of the apparatus is heated to 450 to 600 ° C. with a heater, and then is rotated to −200 V on the rotating tool base while rotating on the rotary table. Then, the tool base surface is cleaned with Ar gas bombardment by further applying a pulse bias voltage of
(B) Next, argon gas is introduced as a reaction gas into the apparatus to form a reaction atmosphere of 0.3 Pa, and a high frequency power of 300 W is applied to the target of the TiB 2 sintered body using a high frequency power source and sputtered. In addition, a lower layer (TiB 2 layer) having a target layer thickness is formed on the surface of the tool base that rotates while rotating on the rotary table by applying a pulse voltage of −200 V,
(C) Next, an argon-nitrogen mixed gas is introduced as a reaction gas into the apparatus, and while adjusting the nitrogen content to increase with the progress of sputtering, the reaction atmosphere is set to 0.3 Pa, and the rotation A DC bias voltage of −100 V is applied to the rotating tool base while rotating on the table, and sputtering is performed on the target of the TiB 2 sintered body using a high-frequency power source, and a high-frequency power source is used on the metal Ti target. Sputtering is performed, and each applied power is adjusted to be a target structure, and an intermediate layer (TiB 2 -TiN mixed layer) having a target layer thickness and a target gradient structure is formed on the surface of the tool base,
(D) Next, nitrogen gas is introduced as a reaction gas into the apparatus to form a reaction atmosphere of 2 to 4 Pa, and a pulse bias voltage of −10 to −50 V is applied to the tool base that rotates while rotating on the rotary table. Then, an arc discharge is generated by flowing a current of 100 A between the cathode electrode and the anode electrode made of the Ti—Al alloy, so that the tool substrate surface has the target composition and target layer thickness shown in Table 2. By depositing an upper layer consisting of a TiAlN layer,
The present invention coated cBN-based sintered tools 1 to 10 (referred to as the present invention tools 1 to 10) each having a throwaway tip shape defined in ISO standard TNGA160408 were manufactured.
(E) Further, as shown in the cross-sectional view of FIG. 2, the rake face and the upper layer of the honing face of the coated cBN-based sintered tool of the present invention having a throwaway tip shape are removed by wet blasting to expose the intermediate layer. . Wet blasting is performed by injecting a polishing liquid, which is a liquid (generally water) containing a jetting abrasive, onto a workpiece to perform polishing, as well as machining using an elastic grindstone or brush, Even when compared with the blasting process, the liquid attenuates the kinetic energy of the jetting abrasive between the object and the object to be processed, so that soft processing with relatively weak processing energy is achieved. For this reason, by using it for the removal of the outermost layer as in the present invention, it is possible to reduce the occurrence of polishing scratches on the exposed intermediate layer surface. For example, the arithmetic average roughness Ra is 0.1 μm or less. It is possible to form a rake surface and a honing surface with a smooth surface roughness.
The thickness of the intermediate layer after removal of the outermost layer is 0.3 to 0.9 μm.
また、比較の目的で、
前記工具基体Ａ〜Ｊに対して、前記と同様の方法で硬質被覆層を形成し、前記（ｅ）の工程を行わず、すなわち、すくい面とホーニング面の上部層の除去を行わずに、表２に示される目標組成および目標層厚の硬質被覆層を蒸着形成した比較被覆ｃＢＮ基焼結工具１〜１０（比較工具１〜１０という）をそれぞれ製造した。
For comparison purposes,
For the tool bases A to J, a hard coating layer is formed by the same method as described above, and without performing the step (e), that is, without removing the upper layer of the rake face and the honing face, Comparative coated cBN-based sintered tools 1 to 10 (referred to as comparative tools 1 to 10) each having a hard coating layer having a target composition and a target layer thickness shown in Table 2 formed by vapor deposition were manufactured.
この結果得られた本発明被覆ｃＢＮ基焼結工具１〜１０および比較被覆ｃＢＮ基焼結工具１〜１０の硬質被覆層の各層について、その組成をオージェ電子分光分析法により測定したところ、それぞれ目標組成と実質的に同じ組成を示した。
なお、表２における中間層のＢ、Ｎ含有割合について、下部層側とは、０．１μｍ（膜厚方向）×１μｍ（界面と平行な方向）の領域での測定の平均値、上部層側とは、同様に、０．１μｍ（膜厚方向）×１μｍ（界面と平行な方向）の領域での測定の平均値をいい、また、平均組成（Ｘ値）、平均組成（Ｙ値）とは、中間層の全体（中間層厚）×幅１μｍの領域により測定した値をいう。
さらに、本発明被覆ｃＢＮ基焼結工具１〜１０および比較被覆ｃＢＮ基焼結工具１〜１０の各層の層厚を透過型電子顕微鏡を用いて断面測定したところ、いずれも目標層厚と実質的に同じ平均値（５ヶ所の平均値）を示した。
About each layer of the hard coating layer of the present invention coated cBN-based sintered tool 1-10 and comparative coated cBN-based sintered tool 1-10 obtained as a result, the composition was measured by Auger electron spectroscopic analysis. The composition was substantially the same as the composition.
In addition, regarding the B and N content ratio of the intermediate layer in Table 2, the lower layer side is the average value of the measurement in the region of 0.1 μm (film thickness direction) × 1 μm (direction parallel to the interface), the upper layer side Means the average value of the measurement in the region of 0.1 μm (film thickness direction) × 1 μm (direction parallel to the interface), and the average composition (X value) and average composition (Y value) Denotes a value measured by a region of the entire intermediate layer (intermediate layer thickness) × width 1 μm.
Further, when the layer thicknesses of the respective layers of the present coated cBN-based sintered tool 1 to 10 and the comparative coated cBN-based sintered tool 1 to 10 were measured with a transmission electron microscope, both were substantially equal to the target layer thickness. The same average value (average value of 5 locations) was shown.
つぎに、前記各種の被覆ｃＢＮ基焼結工具を、いずれも工具鋼製バイトの先端部に固定治具にてネジ止めした状態で、本発明被覆ｃＢＮ基焼結工具１〜１０および比較被覆ｃＢＮ基焼結工具１〜１０ついて、以下に示す切削条件Ａ、Ｂで高硬度鋼の高速重切削試験を実施した。
[切削条件Ａ]
被削材：ＦＣＤ７００、
切削速度： ３５０ ｍ／ｍｉｎ．、
切り込み： ０．２ ｍｍ、
送り： ０．１５ ｍｍ／ｒｅｖ．、
切削時間： １５ 分、
の条件でのダクタイル鋳鉄の乾式・高速連続切削加工試験。逃げ面摩耗量が０．５ｍｍに達するまでの切削時間を工具の寿命とする。（通常の切削条件は、切削速度：２５０ｍ／ｍｉｎ．、切り込み：０．２ｍｍ、送り：０．１５ｍｍ／ｒｅｖ．）、
[切削条件Ｂ]
被削材： ０．５Ｃ−１．５Ｃｕ−４Ｎｉ−０．５Ｍｏ−残Ｆｅ
切削速度： １９０ ｍ／ｍｉｎ．、
切り込み： ０．１５ ｍｍ、
送り： ０．２ ｍｍ／ｒｅｖ．、
切削時間： １５ 分、
の条件での焼結合金の湿式・断続切削加工試験。刃先が欠損するまでの切削時間を工具寿命とする。（通常の切削条件は、切削速度：１５０ｍｍ／ｍｉｎ．、切り込み：０．１ｍｍ、送り：０．１５ｍｍ／ｒｅｖ．）。
表３に、切削加工試験結果を示す。
Next, the coated cBN-based sintered tool of the present invention and the comparative coated cBN of the present invention are all in the state where each of the various coated cBN-based sintered tools is screwed to the tip of the tool steel tool with a fixing jig. With respect to the base sintered tools 1 to 10, high-speed heavy cutting tests of high hardness steel were performed under the cutting conditions A and B shown below.
[Cutting conditions A]
Work material: FCD700,
Cutting speed: 350 m / min. ,
Cutting depth: 0.2 mm,
Feed: 0.15 mm / rev. ,
Cutting time: 15 minutes,
Dry / high-speed continuous cutting test of ductile cast iron under the following conditions. The cutting time until the flank wear amount reaches 0.5 mm is defined as the tool life. (Normal cutting conditions are cutting speed: 250 m / min., Cutting: 0.2 mm, feeding: 0.15 mm / rev.),
[Cutting conditions B]
Work Material: 0.5C-1.5Cu-4Ni-0.5Mo-Remaining Fe
Cutting speed: 190 m / min. ,
Cutting depth: 0.15 mm,
Feed: 0.2 mm / rev. ,
Cutting time: 15 minutes,
Wet / intermittent cutting test of sintered alloy under the following conditions. The cutting time until the cutting edge is broken is defined as the tool life. (Normal cutting conditions are cutting speed: 150 mm / min., Cutting: 0.1 mm, feeding: 0.15 mm / rev.).
Table 3 shows the cutting test results.
表２〜３に示される結果から、本発明被覆ｃＢＮ基焼結工具は、ｃＢＮの配合割合が７０容量％以上の工具基体表面に、下部層、中間層および上部層からなる硬質被覆層を形成し、かつ、下部層をＴｉＢ２層、中間層を組織傾斜構造を有する特定組成のＴｉＢ２−ＴｉＮ混合層、また、上部層を特定組成のＴｉＡｌＮ層とするとともに、すくい面およびホーニング面の上部層を除去したことによって、ｃＢＮ含有割合の高い工具基体に対しても、硬質被覆層は特にすぐれた付着強度を備え、さらに、高温硬さ、靭性、耐衝撃性、潤滑性、耐溶着性を兼ね備えることから、ダクタイル鋳鉄や焼結合金などのフェライト相が多く析出した被削材の、高熱発生を伴い、かつ、切刃に対して高負荷が作用する高速連続切削及び断続切削条件下で用いた場合であっても、前記硬質被覆層に、欠損、剥離、溶着等の発生はなく、長期の使用に亘って、すぐれた耐摩耗性、耐欠損性を発揮することができる。
これに対して、すくい面およびホーニング面の上部層の除去を行わない比較被覆ｃＢＮ基焼結工具は、潤滑性、耐溶着性が十分でないため、被削材とＴｉＡｌＮ層との間で溶着が発生し、そのため、被覆膜の剥離によりチッピングが発生しやすく、また、被削材とＴｉＡｌＮ層との間で潤滑性が悪く、そのため、クレータ磨耗が発生しやすく耐摩耗性、耐欠損性に劣るため、比較的短時間で使用寿命に至ることが明らかである。
From the results shown in Tables 2-3, the coated cBN-based sintered tool of the present invention forms a hard coating layer composed of a lower layer, an intermediate layer, and an upper layer on the surface of a tool base having a cBN blending ratio of 70% by volume or more. In addition, the lower layer is a TiB 2 layer, the intermediate layer is a TiB 2 -TiN mixed layer having a structure gradient structure, the upper layer is a TiAlN layer having a specific composition, and the upper part of the rake face and the honing face By removing the layer, the hard coating layer has excellent adhesion strength even for tool substrates with a high cBN content ratio. Furthermore, it has high temperature hardness, toughness, impact resistance, lubricity, and welding resistance. Because it combines, it is used under high-speed continuous cutting and intermittent cutting conditions that cause high heat generation and a high load acts on the cutting edge of the work material with a large amount of ferrite phase such as ductile cast iron and sintered alloy. Even if, in the hard coating layer, defects, peeling, no occurrence of welding or the like, over a long period of use, excellent wear resistance can be exhibited chipping resistance.
On the other hand, the comparative coated cBN-based sintered tool that does not remove the upper layer of the rake face and the honing face has insufficient lubricity and welding resistance, so that welding between the work material and the TiAlN layer does not occur. Therefore, chipping is likely to occur due to peeling of the coating film, and lubricity is poor between the work material and the TiAlN layer, so that crater wear is likely to occur, resulting in wear resistance and fracture resistance. Since it is inferior, it is clear that the service life is reached in a relatively short time.
前述のように、本発明被覆ｃＢＮ基焼結工具は、各種の鋼や鋳鉄などの通常の切削条件での切削加工は勿論のこと、特にダクタイル鋳鉄や焼結合金などのフェライト相が多く析出した被削材の高速連続切削加工及び断続切削加工であっても、前記硬質被覆層がすぐれた付着強度、潤滑性を有し耐摩耗性、耐欠損性、耐溶着性に優れるため、長期に亘って安定した切削性能を発揮するものであるから、切削加工装置の高性能化、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。 As described above, the coated cBN-based sintered tool of the present invention has a large amount of ferrite phase such as ductile cast iron and sintered alloy, as well as cutting under normal cutting conditions such as various steels and cast iron. Even in high-speed continuous cutting and intermittent cutting of work materials, the hard coating layer has excellent adhesion strength, lubricity, and excellent wear resistance, fracture resistance, and welding resistance. Therefore, it can sufficiently satisfy the high performance of the cutting device, the labor saving and energy saving of the cutting work, and the cost reduction.
Claims (2)
（ａ）前記下部層は、０．０５〜０．５μｍの層厚を有するＴｉＢ２層、
（ｂ）前記中間層は、０．３〜１μｍの層厚を有し、
組成式：Ｔｉ１−Ｘ−ＹＢＸＮＹ
で表した場合、０．１５≦Ｘ≦０．６０、０．０５≦Ｙ≦０．３５、０．５０≦Ｘ＋Ｙ≦０．６５（但し、Ｘ、Ｙはいずれも原子比）を満足する平均組成を有し、さらに、下部層側から上部層側へ向うにしたがって、Ｘの値は次第に減少し、Ｙの値は次第に増加する傾斜組織構造を有するＴｉＢ２相とＴｉＮ相との２相混合層、
（ｃ）前記上部層は、０．５〜５μｍの層厚を有し、
組成式：（Ｔｉ１−ＺＡｌＺ）Ｎ層
で表した場合、Ｚが０．３〜０．６５（但し、Ｚは原子比）であるＴｉとＡｌの複合窒化物層、
であるとともに、
（ｄ）前記工具本体のすくい面とホーニング面は、前記上部層が除去されることにより中間層が主として露出していることを特徴とする表面被覆立方晶窒化ほう素基超高圧焼結材料製切削工具。 A cutting edge portion is formed on the surface of the tool body with honing at the intersection ridge line portion of the rake face and flank face of the tool body using a cubic boron nitride-based ultrahigh pressure sintered material as a base material. In the cutting tool made of surface-coated cubic boron nitride-based ultra-high pressure sintered material in which a hard coating layer consisting of a lower layer, an intermediate layer and an upper layer is vapor-deposited in order from the tool body side,
(A) The lower layer is a TiB 2 layer having a layer thickness of 0.05 to 0.5 μm,
(B) the intermediate layer has a layer thickness of 0.3-1 μm;
Composition formula: Ti 1-XY B X N Y
In this case, an average satisfying 0.15 ≦ X ≦ 0.60, 0.05 ≦ Y ≦ 0.35, 0.50 ≦ X + Y ≦ 0.65 (where X and Y are atomic ratios) Two-phase mixing of TiB 2 phase and TiN phase having a gradient structure in which the value of X gradually decreases and the value of Y gradually increases as it moves from the lower layer side to the upper layer side. layer,
(C) the upper layer has a layer thickness of 0.5-5 μm;
Composition formula: (Ti 1-Z Al Z ) When represented by an N layer, a composite nitride layer of Ti and Al in which Z is 0.3 to 0.65 (where Z is an atomic ratio),
And
(D) The rake face and the honing face of the tool body are made of a surface-coated cubic boron nitride-based ultrahigh pressure sintered material, wherein the intermediate layer is mainly exposed by removing the upper layer. Cutting tools.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CZ304957B6 (en) * | 2013-07-11 | 2015-02-04 | Technická univerzita v Liberci | Coated pressing or forming tools |
| CN111254401A (en) * | 2020-03-09 | 2020-06-09 | 浙江申吉钛业股份有限公司 | Method for improving adhesion strength of hard wear-resistant nano coating of titanium alloy plate |
| WO2020166167A1 (en) * | 2019-02-14 | 2020-08-20 | Ｔｏｗａ株式会社 | Method for manufacturing film formation product and sputtering method |
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2010
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CZ304957B6 (en) * | 2013-07-11 | 2015-02-04 | Technická univerzita v Liberci | Coated pressing or forming tools |
| WO2020166167A1 (en) * | 2019-02-14 | 2020-08-20 | Ｔｏｗａ株式会社 | Method for manufacturing film formation product and sputtering method |
| JP2020132906A (en) * | 2019-02-14 | 2020-08-31 | Ｔｏｗａ株式会社 | Manufacturing method of film-formed product, and sputtering device |
| TWI737048B (en) * | 2019-02-14 | 2021-08-21 | 日商Ｔｏｗａ股份有限公司 | Method for manufacturing film-forming product and sputtering device |
| KR20210103509A (en) * | 2019-02-14 | 2021-08-23 | 토와 가부시기가이샤 | Manufacturing method and sputtering device for film-forming products |
| KR102615201B1 (en) * | 2019-02-14 | 2023-12-19 | 토와 가부시기가이샤 | Manufacturing method and sputtering device for deposited products |
| CN111254401A (en) * | 2020-03-09 | 2020-06-09 | 浙江申吉钛业股份有限公司 | Method for improving adhesion strength of hard wear-resistant nano coating of titanium alloy plate |
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