JP5418833B2 - Cutting tool made of surface coated cubic boron nitride based ultra high pressure sintered material - Google Patents
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この発明は、合金工具鋼や軸受け鋼の焼入れ材などの高硬度材を高速断続切削加工した場合でも、硬質被覆層がすぐれた耐溶着性、耐チッピング性、耐摩耗性を有し、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。 This invention has excellent welding resistance, chipping resistance, and abrasion resistance even when high-hardness materials such as hardened materials of alloy tool steel and bearing steel are subjected to high-speed intermittent cutting. Surface-coated cubic boron nitride-based ultra-high-pressure sintering with a hard coating layer formed on the surface of a cutting tool base made of cubic boron nitride-based ultra-high-pressure sintered material that can exhibit stable cutting performance The present invention relates to a material cutting tool (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、例えば、特許文献１に示されるように、立方晶窒化ほう素基超高圧焼結材料（以下、ｃＢＮ基焼結材料という）で構成された工具本体の表面に、ＴｉＮ層、ＴｉとＡｌの複合窒化物（以下、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、これらを各種の鋼や鋳鉄などの切削加工に用いられていることが知られている。 Further, as a coated cBN-based sintered tool, for example, as shown in Patent Document 1, a tool body made of a cubic boron nitride-based ultrahigh pressure sintered material (hereinafter referred to as a cBN-based sintered material) is used. A coated cBN-based sintered tool is known which is formed by vapor-depositing a surface coating layer such as a TiN layer or a Ti / Al composite nitride (hereinafter referred to as TiAlN) layer on the surface. It is known that it is used for cutting of cast iron and the like.
そしてこれら被覆ｃＢＮ基焼結工具において、その切削性能を高めるためにさらに種々の改良がなされている。
例えば、特許文献２には、工具基体のすくい面と逃げ面との間に、ホーニング面を備えた切刃が形成されるとともに、これらすくい面，ホーニング面，逃げ面にかけて硬質被覆層が形成された被覆ｃＢＮ基焼結工具において、上記ホーニング面上における上記硬質被覆層の層厚を、該ホーニング面と上記すくい面または逃げ面の少なくともいずれか一方との稜線部において、他のホーニング面上の部分よりも小さくすることによって、被覆ｃＢＮ基焼結工具の硬質膜の剥離を防止し、その耐摩耗性を高めることが知られている。
In these coated cBN-based sintered tools, various improvements have been made in order to enhance the cutting performance.
For example, in Patent Document 2, a cutting blade having a honing surface is formed between a rake surface and a flank surface of a tool base, and a hard coating layer is formed on the rake surface, the honing surface, and the flank surface. In the coated cBN-based sintered tool, the layer thickness of the hard coating layer on the honing surface is set on the other honing surface at the ridge line portion between the honing surface and at least one of the rake surface and the flank surface. It is known that by making it smaller than the portion, peeling of the hard film of the coated cBN-based sintered tool is prevented and its wear resistance is improved.
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、上記従来のｃＢＮ基焼結工具においては、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、合金工具鋼や軸受け鋼の焼入れ材などの高硬度材の高速断続切削に用いた場合には、切刃部に発生する高熱により被削材および切粉は高温に加熱されるため、特に切刃の稜線部において被削材との溶着が発生しやすくなり、さらに、切刃には衝撃的な高負荷が断続的に作用するため、切刃の刃先に境界異常損傷を生じ、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 cBN-based sintered tool, there is no particular problem when various steels and cast irons are cut under normal conditions. When used for high-speed intermittent cutting of hard materials such as alloy tool steel and bearing steel quenching materials, the work material and chips are heated to high temperatures due to the high heat generated at the cutting edge. The edge of the blade tends to be welded to the work material, and the cutting blade is subjected to high impact loads intermittently. The current situation is that the service life is reached in time.
そこで、本発明者等は、上述のような観点から、合金工具鋼や軸受け鋼の焼入れ材などの高硬度材の高速断続切削加工で、硬質被覆層がすぐれた耐溶着性を備えるとともに、すぐれた耐チッピング性、耐摩耗性を発揮する被覆ｃＢＮ基焼結工具を開発すべく、硬質被覆層の材質と構造の両面から研究を行った結果、次のような知見を得た。
まず、硬質被覆層の材質の面からは、前記特許文献１にも示されているように、
（イ） 硬質被覆層の下部層を、
組成式：（Ｔｉ１−ＸＡｌＸ）Ｎ
で表した場合、Ｘが０．３〜０．６（但し、原子比）である０．５〜４μｍの平均層厚を有するＴｉＡｌＮ層、
（ロ）硬質被覆層の上部層を、それぞれ一層平均層厚が０．０３〜０．３μｍの薄層Ａと薄層Ｂの交互積層構造として構成し、かつ、
薄層Ａを、
組成式：（Ｔｉ１−ＸＡｌＸ）Ｎ
で表した場合、Ｘが０．３〜０．６（但し、原子比）であるＴｉＡｌＮ層、
薄層Ｂを、ＴｉＮ層で構成した場合には、
合金工具鋼や軸受け鋼の焼入れ材などの高硬度材の高速切削加工において、境界異常損傷、欠損の発生を一定程度は防止することができる。
しかし、切刃に対して、衝撃的な高負荷が断続的に作用する高速断続切削加工においては、前記特許文献１に開示された被覆ｃＢＮ基焼結工具では、境界異常損傷、欠損の発生防止は十分に満足できるものではない。
In view of the above, the inventors of the present invention have excellent welding resistance with a hard coating layer in high-speed intermittent cutting of hard materials such as hardened materials of alloy tool steel and bearing steel. In order to develop a coated cBN-based sintered tool that exhibits excellent chipping resistance and wear resistance, the following findings were obtained as a result of research on both the material and structure of the hard coating layer.
First, from the surface of the material of the hard coating layer, as shown in Patent Document 1,
(B) Lower layer of hard coating layer
Composition formula: (Ti 1-X Al X ) N
And a TiAlN layer having an average layer thickness of 0.5 to 4 μm where X is 0.3 to 0.6 (however, atomic ratio),
(B) The upper layer of the hard coating layer is configured as an alternately laminated structure of thin layers A and B each having an average layer thickness of 0.03 to 0.3 μm, and
Thin layer A
Composition formula: (Ti 1-X Al X ) N
In the case of TiAlN layer where X is 0.3 to 0.6 (however, atomic ratio),
When the thin layer B is composed of a TiN layer,
In high-speed cutting of hard materials such as hardened materials of alloy tool steel and bearing steel, it is possible to prevent the occurrence of abnormal boundary damage and chipping to a certain extent.
However, in the high-speed intermittent cutting process in which a shocking high load acts intermittently on the cutting edge, the coated cBN-based sintered tool disclosed in Patent Document 1 prevents the occurrence of abnormal boundary damage and defects. Is not fully satisfactory.
そこで、本発明者等は、被覆層の構造という観点からさらに研究を進めたところ、前記特許文献１に示される交互積層構造からなる上部層構造において、ホーニング面と逃げ面との稜線部以外の領域の最外層を薄層Ａと同組成のＴｉＡｌＮ層で構成するとともに、その層厚を０．１〜０．８μｍとし、一方、ホーニング面と逃げ面との稜線部においては、薄層Ａ（ＴｉＡｌＮ層）と薄層Ｂ（ＴｉＮ層）との交互積層断面を露出形成させることによって、一段と、耐溶着性の向上を図り得るとともに、耐チッピング性、耐摩耗性に優れた被覆ｃＢＮ基焼結工具が得られることを見出したのである。 Therefore, the present inventors have further researched from the viewpoint of the structure of the coating layer, and in the upper layer structure composed of the alternately laminated structure shown in Patent Document 1, other than the ridge line portion between the honing surface and the flank surface. The outermost layer of the region is composed of a TiAlN layer having the same composition as that of the thin layer A, and the layer thickness is 0.1 to 0.8 μm. On the other hand, in the ridge line portion between the honing surface and the flank surface, the thin layer A ( By exposing the alternately laminated cross section of TiAlN layer) and thin layer B (TiN layer), it is possible to further improve the welding resistance, and to improve the chipping resistance and wear resistance. They found that a tool could be obtained.
この発明は、上記知見に基づいてなされたものであって、
「立方晶窒化ほう素を５０〜８５体積％含有する立方晶窒化ほう素基超高圧焼結材料からなる工具基体表面に下部層と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）上記工具基体は、ホーニングの幅がすくい面方向からみて０．０３〜０．３ｍｍ、ホーニングの角度がすくい面とのなす角度で１０〜３５度の範囲にあるホーニング形状を有し、
（ｂ）上記硬質被覆層の下部層は、
組成式：（Ｔｉ１−ＸＡｌＸ）Ｎ
で表した場合、Ｘが０．３〜０．６（但し、原子比）である０．５〜４μｍの平均層厚を有するＴｉとＡｌの複合窒化物層からなり、
（ｃ）上記硬質被覆層の上部層は、それぞれ一層平均層厚が０．０３〜０．３μｍの薄層Ａと薄層Ｂの交互積層構造からなり、
上記薄層Ａは、上記ＴｉとＡｌの複合窒化物層、
上記薄層Ｂは、Ｔｉの窒化物層であり、
（ｄ）上記上部層の最外層は、ホーニング面と逃げ面との稜線部以外は平均層厚が０．１〜０．８μｍの上記ＴｉとＡｌの複合窒化物層で構成され、一方、ホーニング面と逃げ面との稜線部においては、上記最外層は存在せず上記薄層Ａと薄層Ｂの交互積層断面構造が露出形成され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（被覆ｃＢＮ基焼結工具）。」
に特徴を有するものである。
This invention has been made based on the above findings,
“Surface-coated cubic nitriding in which a hard coating layer consisting of a lower layer and an upper layer is deposited on the surface of a tool substrate made of a cubic boron nitride-based ultrahigh pressure sintered material containing 50 to 85 volume% of cubic boron nitride. In a cutting tool made of boron-based ultra-high pressure sintered material,
(A) The tool base has a honing shape in which the honing width is 0.03 to 0.3 mm when viewed from the rake face direction, and the honing angle is in the range of 10 to 35 degrees with respect to the rake face.
(B) The lower layer of the hard coating layer is
Composition formula: (Ti 1-X Al X ) N
X is 0.3 to 0.6 (provided that the atomic ratio) is composed of a composite nitride layer of Ti and Al having an average layer thickness of 0.5 to 4 μm,
(C) The upper layer of the hard coating layer is composed of an alternating laminated structure of thin layers A and B each having an average layer thickness of 0.03 to 0.3 μm,
The thin layer A is a composite nitride layer of Ti and Al,
The thin layer B is a Ti nitride layer,
(D) The outermost layer of the upper layer is composed of a composite nitride layer of Ti and Al having an average layer thickness of 0.1 to 0.8 μm except for the ridge line portion between the honing surface and the flank surface. The surface-coated cubic boron nitride group is characterized in that the outermost layer does not exist at the ridge line portion between the face and the flank face, and the alternately laminated sectional structure of the thin layer A and the thin layer B is exposed. Cutting tool made of ultra-high pressure sintered material (coated cBN-based sintered tool). "
It has the characteristics.
つぎに、この発明の被覆ｃＢＮ基焼結工具において、詳細に説明する。 Next, the coated cBN-based sintered tool of the present invention will be described in detail.
（ａ）ｃＢＮ基焼結材料：
超高圧焼結材料製工具基体中のｃＢＮ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が図れるが、その配合割合が少なすぎると所望のすぐれた耐摩耗性を確保することができず、一方その配合割合が多くなりすぎると、ｃＢＮ基材料自体の焼結性が低下し、この結果切刃に欠損が生じやすくなることから、ｃＢＮの配合割合は、５０〜８５体積％とする。
なお、ｃＢＮ基焼結材料には、その成分として、例えば、Ｔｉ化合物，Ａｌおよび／またはＡｌ２Ｏ３，ＷＣ等が含有されるが、この発明においては、これらの含有量を特に制限するものではない。
しかし、例えば、Ｔｉ化合物（ＴｉＮ、ＴｉＣＮおよびＴｉＣのうちから選ばれる１種又は２種以上）については、焼結性を向上させるとともに焼結体中で連続相を形成して強度を向上させる作用があるが、その配合割合が少なすぎては所望の強度を確保することができず、一方その配合割合が多すぎては相対的にｃＢＮの含有量が少なくなり、すくい面摩耗などが生じやすくなることから、これらの観点からその配合量を定めることが望ましい。
また、Ａｌおよび／またはＡｌ２Ｏ３は焼結時に優先的にｃＢＮ粉末の表面に凝集し、反応して反応生成物を形成し、焼結後のｃＢＮ基材料中で、連続相を形成するＴｉ化合物相と硬質分散相を形成するｃＢＮ相の間に介在するようになり、この反応生成物は前記連続相を形成するＴｉ化合物相と硬質分散相を形成するｃＢＮ相のいずれとも強固に密着接合する性質をもつことから、前記ｃＢＮ相の連続結合相であるＴｉ化合物相に対する密着性が著しく向上させ、切刃の耐チッピング性を向上させるが、その量が多くなりすぎると、ｃＢＮの含有量が少なくなり、すくい面摩耗などが生じやすくなることから、これらの観点からその配合量を定めることが必要である。
さらに、ＷＣについては、ｃＢＮ粒子の近傍でＷのホウ化物を生成し、ＴｉＢ２の生成を抑制するため、耐チッピング性の向上に寄与するが、ＷＣ含有量が多すぎると、ＷＣ成分が残留し、逆に耐チッピング性の低下を招くことから、ＷＣの配合割合は少量とすることが望ましい。
(A) cBN-based sintered material:
The cBN in the tool base made of an ultra-high pressure sintered material is extremely hard and forms a dispersed phase in the sintered material, and this dispersed phase can improve the wear resistance, but if the blending ratio is too small, it is desirable. However, if the blending ratio is too large, the sinterability of the cBN base material itself is lowered, and as a result, the cutting blade tends to be damaged. The mixing ratio is set to 50 to 85% by volume.
The cBN-based sintered material contains, for example, a Ti compound, Al and / or Al 2 O 3 , WC, etc. as components, but in the present invention, these contents are particularly limited. is not.
However, for example, for a Ti compound (one or more selected from TiN, TiCN and TiC), the effect of improving the sinterability and improving the strength by forming a continuous phase in the sintered body. However, if the blending ratio is too small, the desired strength cannot be ensured. On the other hand, if the blending ratio is too large, the cBN content is relatively small, and rake face wear tends to occur. Therefore, it is desirable to determine the blending amount from these viewpoints.
Further, Al and / or Al 2 O 3 preferentially aggregates on the surface of the cBN powder during the sintering, reacts to form a reaction product, and forms a continuous phase in the sintered cBN-based material. The reaction product is firmly attached to both the Ti compound phase forming the continuous phase and the cBN phase forming the hard dispersed phase. Since it has the property of bonding, the adhesion of the cBN phase to the Ti compound phase, which is the continuous bonding phase, is remarkably improved, and the chipping resistance of the cutting edge is improved. Since the amount decreases and rake face wear or the like tends to occur, it is necessary to determine the blending amount from these viewpoints.
Furthermore, for WC, a boride of W is generated in the vicinity of the cBN particles, and the generation of TiB 2 is suppressed, which contributes to the improvement of chipping resistance. However, if the WC content is excessive, the WC component remains. On the other hand, since the chipping resistance is lowered, it is desirable that the blending ratio of WC is small.
（ｂ）ホーニング形状：
本発明のｃＢＮ基焼結材料からなる工具本体のホーニング形状は、図１に示すように、ホーニングの幅がすくい面方向からみて０．０３〜０．３ｍｍ、ホーニングの角度がすくい面とのなす角度で１０〜３５度の範囲とする。
これは、刃先強度を確保するための形状であり、ホーニングの角度については、１０度以下では刃先強度が保てなくなり、３５度以上になると切削時のすくい角が負に大きくなりすぎて切れ味が低下する。また、ホーニング幅について、０．０３ｍｍ未満では刃先強度が確保できず、一方、０．３ｍｍを超えると刃先抵抗が大きくなり切れ味の低下を招くという理由による。
(B) Honing shape:
As shown in FIG. 1, the honing shape of the tool body made of the cBN-based sintered material of the present invention is such that the honing width is 0.03 to 0.3 mm when viewed from the rake face direction, and the honing angle is the rake face. The angle is in the range of 10 to 35 degrees.
This is a shape for ensuring the strength of the cutting edge. When the honing angle is 10 degrees or less, the cutting edge strength cannot be maintained. When the honing angle is 35 degrees or more, the rake angle at the time of cutting becomes too negative and the sharpness becomes sharp. descend. In addition, when the honing width is less than 0.03 mm, the strength of the blade edge cannot be ensured, and when it exceeds 0.3 mm, the resistance of the blade edge increases and the sharpness decreases.
（ｃ）硬質被覆層の下部層：
硬質被覆層の下部層を構成する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、硬質被覆層の下部層を構成する（Ｔｉ１−ＸＡｌＸ）Ｎ層は、所定の高温強度、高温硬さおよび耐酸化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の高速断続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、Ａｌの含有割合Ｘが６０原子％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Ｘが３０原子％未満になると、高温硬さと耐酸化性が低下し、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Ｘの値を０．３〜０．６と定めた。
また、下部層の平均層厚が０．５μｍ未満では、自身のもつ耐酸化性、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、一方その平均層厚が４μｍを越えると、欠損が生じ易くなることから、その平均層厚を０．５〜４μｍと定めた。
(C) The lower layer of the hard coating layer:
The Ti component in the TiAlN layer constituting the lower layer of the hard coating layer maintains the high temperature strength, and the Al component contributes to the improvement of the high temperature hardness and the oxidation resistance. Therefore, the lower layer of the hard coating layer is formed (Ti 1− X Al X) N layer, a predetermined high-temperature strength, a layer having a high-temperature hardness and oxidation resistance, switching at a high speed interrupted cutting of high-hardness material such as hardened material of an alloy tool steel or bearing steel Basically plays the role of ensuring the wear resistance of the blade. However, if the Al content ratio X exceeds 60 atomic%, the high-temperature strength decreases due to a change in the crystal structure, and defects tend to occur. On the other hand, if the Al content ratio X is less than 30 atomic%, Since the oxidation resistance is lowered, and as a result, the wear resistance is lowered, the value of the Al content ratio X is set to 0.3 to 0.6.
Moreover, if the average layer thickness of the lower layer is less than 0.5 μm, the oxidation resistance, high temperature hardness and high temperature strength possessed by itself cannot be imparted to the hard coating layer over a long period of time, resulting in a short tool life. When the average layer thickness exceeds 4 μm, defects are likely to occur. Therefore, the average layer thickness was set to 0.5 to 4 μm.
なお、超高圧焼結材料製切削工具基体と下部層との十分な密着性を確保するために、基体と下部層との間にＴｉＮの薄層を介在させることができるが、該ＴｉＮの薄層の層厚は０．０１μｍ以上０．５μｍ以下とすることが望ましい。 A thin layer of TiN can be interposed between the base and the lower layer in order to ensure sufficient adhesion between the cutting tool base made of the ultra-high pressure sintered material and the lower layer. The layer thickness is preferably 0.01 μm or more and 0.5 μm or less.
（ｄ）硬質被覆層の上部層：
上部層の薄層Ａ：
上部層の薄層Ａを構成するＴｉＡｌＮ層は、薄層Ａと薄層Ｂとで交互積層構造を構成することにより、薄層Ｂの有する靭性、耐衝撃性を損なうことなしに、薄層Ｂに不足する特性（高温硬さ、高温強度、耐酸化性）を補完する。
しかも、交互積層構造を構成するにあたり、ホーニング部以外の箇所（主として、逃げ面）については、上部層の最外層をＴｉＡｌＮ層で構成することによって高硬度鋼の高速断続切削に耐え得る耐摩耗性を確保する。
（なお、ホーニング部の層構造については、後記する。）
そして、薄層Ａを構成するＴｉＡｌＮ層は、
組成式：（Ｔｉ１−ＸＡｌＸ）Ｎ層
で表した場合、下部層（組成式（Ｔｉ１−ＸＡｌＸ）Ｎで表されるＴｉＡｌＮ層）の場合と同様、すぐれた高温硬さ、高温強度、耐酸化性を具備し、薄層Ｂに不足する特性を補完するために、Ｘの値を０．３〜０．６に定めた。
なお、硬質被覆層の下部層と薄層Ａを構成する材料は同一成分系の材料であるから、例えば、物理蒸着であるアークイオンプレーティングで成膜する際に、一種類のターゲットを用いて下部層（のＴｉＡｌＮ層）と薄層Ａ（のＴｉＡｌＮ層）を形成した場合には、同一組成のＴｉＡｌＮ層が形成される。ただ、下部層のＴｉＡｌＮ層と、薄層ＡのＴｉＡｌＮ層は、必ずしも同一組成である必要はなく、物理蒸着を行う際、例えば、異なった組成の複数のターゲットを使用した場合には、下部層と薄層Ａは異なった組成のＴｉＡｌＮ層が形成されるが、いずれの場合でも、Ｔｉとの合量に占めるＸの含有割合（原子比）がそれぞれ０．３〜０．６の範囲内であれば、硬質被覆層の特性上何らの不都合を生じるものではない。
また、上部層の薄層Ｂは、後記するように、所定の靭性、耐衝撃性を備えた層であり、高硬度材の高速断続切削加工時における境界異常損傷、欠損の発生を抑制するが、その一方で、高温硬さの不足により耐摩耗性の低下が生じやすいので、すぐれた高温硬さ、高温強度、耐酸化性を備えた上記薄層Ａを薄層Ｂと交互に積層することにより、高温硬さの不足を補完し、しかも薄層Ｂの有する特性を劣化させることなく、交互積層構造からなる上部層全体として、すぐれた高温硬さ、靭性、耐衝撃性を確保するが、薄層Ａの一層平均層厚が０．０３μｍ未満ではＴｉＮ層の高温硬さの低下を補うことはできず、一方、その一層平均層厚が０．３μｍを超えると、チッピングを発生しやすくなるので、薄層Ａの一層平均層厚は、０．０３〜０．３μｍと定めた。
(D) Upper layer of hard coating layer:
Upper layer A:
The TiAlN layer constituting the thin layer A of the upper layer is composed of the thin layer A and the thin layer B, thereby forming a thin layer B without impairing the toughness and impact resistance of the thin layer B. Complements the properties (high temperature hardness, high temperature strength, oxidation resistance) that are lacking in
In addition, in constructing the alternate laminated structure, the wear resistance that can withstand high-speed intermittent cutting of high-hardness steel by configuring the outermost layer of the upper layer with a TiAlN layer for the portions other than the honing portion (mainly the flank). Secure.
(The layer structure of the honing part will be described later.)
And the TiAlN layer which comprises the thin layer A is
Composition formula: When represented by a (Ti 1-X Al X ) N layer, as in the case of the lower layer (TiAlN layer represented by a composition formula (Ti 1-X Al X ) N), excellent high-temperature hardness, In order to provide high-temperature strength and oxidation resistance, and to complement the properties lacking in the thin layer B, the value of X was set to 0.3 to 0.6.
In addition, since the material which comprises the lower layer of the hard coating layer and the thin layer A is a material of the same component system, for example, when forming a film by arc ion plating which is physical vapor deposition, a single type of target is used. When the lower layer (the TiAlN layer) and the thin layer A (the TiAlN layer) are formed, a TiAlN layer having the same composition is formed. However, the TiAlN layer of the lower layer and the TiAlN layer of the thin layer A do not necessarily have the same composition, and when performing physical vapor deposition, for example, when a plurality of targets having different compositions are used, the lower layer And in the thin layer A, TiAlN layers having different compositions are formed. In either case, the content ratio (atomic ratio) of X in the total amount with Ti is within the range of 0.3 to 0.6. If it exists, there will be no inconvenience in the characteristics of the hard coating layer.
In addition, as described later, the upper layer thin layer B is a layer having predetermined toughness and impact resistance, and suppresses the occurrence of abnormal boundary damage and defects during high-speed intermittent cutting of a high-hardness material. On the other hand, wear resistance tends to decrease due to lack of high-temperature hardness, so that the thin layers A having excellent high-temperature hardness, high-temperature strength, and oxidation resistance are alternately laminated with the thin layers B. By supplementing the shortage of high temperature hardness, and without deteriorating the properties of the thin layer B, as a whole upper layer consisting of an alternating laminated structure, excellent high temperature hardness, toughness, impact resistance is ensured, If the average layer thickness of the thin layer A is less than 0.03 μm, the decrease in high-temperature hardness of the TiN layer cannot be compensated. On the other hand, if the average layer thickness exceeds 0.3 μm, chipping tends to occur. Therefore, the average layer thickness of the thin layer A is 0.03 to 0.3 μm. It was defined as.
上部層の薄層Ｂ：
上部層の薄層Ｂを構成するＴｉＮ層は、所定の靭性、耐衝撃性を備えるため、高硬度材の高速断続切削加工において、硬質被覆層に境界異常損傷、欠損が発生することを防止する作用を有するが、その一層平均層厚が０．０３μｍ未満では上記のすぐれた特性を十分発揮することはできず、一方、その一層平均層厚が０．３μｍを超えると、上部層の高温硬さが不足し耐摩耗性が低下傾向を示すので、薄層Ｂの一層平均層厚は、０．０３〜０．３μｍと定めた。
Top layer thin layer B:
Since the TiN layer constituting the thin layer B of the upper layer has predetermined toughness and impact resistance, it prevents the occurrence of abnormal boundary damage and chipping in the hard coating layer in high-speed intermittent cutting of a hard material. However, if the average layer thickness is less than 0.03 μm, the above-mentioned excellent characteristics cannot be sufficiently exhibited. On the other hand, if the average layer thickness exceeds 0.3 μm, the upper layer is hardened at high temperature. Therefore, the average layer thickness of the thin layer B is determined to be 0.03 to 0.3 μm.
（ｅ）ホーニング面以外の面（すくい面、逃げ面）における上部層の平均層厚：
ホーニング面以外の面（すくい面、逃げ面）における薄層Ａと薄層Ｂの交互積層構造からなる上部層は、その合計平均層厚が、０．８μｍ未満では、高硬度材の高速断続切削加工で必要とされる十分な靭性、耐衝撃性を発揮することができず、一方その平均層厚が３μｍを越えると、欠損が発生し易くなることから、その平均層厚は０．８〜３μｍとすることが望ましく、かつ、交互積層構造からなる上部層の最外層は、耐摩耗性に優れたＴｉＡｌＮ層で構成することが望ましく、その平均層厚が0.1μｍ未満では耐摩耗性を発揮させるには薄く、一方その平均層厚が0.8μmを越えると、欠損が発生しやすくなることから、その平均層厚は0.1〜0.8μmとすることが望ましい。
(E) Average layer thickness of the upper layer on surfaces other than the honing surface (rake surface, flank surface):
The upper layer composed of the alternating layered structure of thin layers A and B on the surface other than the honing surface (rake surface, flank surface), when the total average layer thickness is less than 0.8 μm, high-speed intermittent cutting of a hard material Sufficient toughness and impact resistance required for processing cannot be exhibited. On the other hand, if the average layer thickness exceeds 3 μm, defects tend to occur. Desirably, the outermost layer of the upper layer composed of an alternately laminated structure is preferably composed of a TiAlN layer having excellent wear resistance. When the average layer thickness is less than 0.1 μm, the wear resistance is exhibited. On the other hand, if the average layer thickness exceeds 0.8 μm, defects are likely to occur. Therefore, the average layer thickness is preferably 0.1 to 0.8 μm.
（ｆ）ホーニング面における上部層：
ホーニング部のホーニング面中央では、上部層の最外層を構成するＴｉＡｌＮ層の平均層厚を０．１〜０．８μｍ、好ましくは、０．１〜０．５μｍ、とするが、ホーニング面と逃げ面との稜線部においては、図２に示すように、最外層を除去し、薄層Ａと薄層Ｂの交互積層断面構造を露出形成させる。
また、ホーニング面と逃げ面との稜線部において、最外層を除去し、薄層Ａと薄層Ｂの交互積層断面構造を形成させる方法としては、例えば、すくい面に対して４３〜４７°の傾斜角で上部層にウエットブラスト処理を行い、ホーニング面と逃げ面との稜線部における最外層を除去し、薄層Ａと薄層Ｂの交互積層断面構造を露出させることにより形成することができる。
本発明は、切刃部およびホーニング部における上記上部層構造を最大の特徴としており、特に、ホーニング面中央および逃げ面では耐摩耗性の高いＴｉＡｌＮ層を最外層として耐摩耗性を確保し、一方、ホーニング面と逃げ面との稜線部においては、薄層Ａと薄層Ｂの交互積層断面構造を露出形成することにより、切刃エッジの硬質被覆層の強度を高め、切刃エッジからの硬質膜の剥離を抑制する。
そして、このような層構造により、合金工具鋼や軸受け鋼の焼入れ材などの高硬度材の高速断続切削において、切刃部に高熱が発生し、切刃部に衝撃的・断続的高負荷が作用したとしても、ホーニング面と逃げ面との稜線部における溶着発生、硬質被覆層の剥離を防止することができ、また、十分な耐摩耗性を確保することができる。
(F) Upper layer on the honing surface:
In the center of the honing surface of the honing portion, the average layer thickness of the TiAlN layer constituting the outermost layer of the upper layer is 0.1 to 0.8 μm, preferably 0.1 to 0.5 μm. At the ridge line with the surface, as shown in FIG. 2, the outermost layer is removed, and the alternately laminated sectional structure of the thin layers A and B is exposed.
Further, as a method of removing the outermost layer at the ridge line portion between the honing surface and the flank surface and forming the alternately laminated cross-sectional structure of the thin layer A and the thin layer B, for example, 43 to 47 ° with respect to the rake surface It can be formed by performing wet blasting on the upper layer at an inclination angle, removing the outermost layer at the ridge line portion of the honing surface and the flank surface, and exposing the alternately laminated sectional structure of the thin layer A and the thin layer B. .
The present invention is characterized by the upper layer structure in the cutting edge portion and the honing portion, and in particular, the wear resistance is ensured by using the TiAlN layer having high wear resistance as the outermost layer at the center and the flank face. In the ridge line portion between the honing surface and the flank surface, the strength of the hard coating layer of the cutting edge is increased by exposing the alternately laminated cross-sectional structure of the thin layer A and the thin layer B, and the hard edge from the cutting edge is hardened. Suppresses film peeling.
And, with such a layer structure, high-speed intermittent cutting of high-hardness materials such as hardened materials of alloy tool steel and bearing steel generates high heat at the cutting edge, and impact and intermittent high load are applied to the cutting edge. Even if it acts, it is possible to prevent the occurrence of welding at the ridge line portion between the honing surface and the flank surface and the peeling of the hard coating layer, and to ensure sufficient wear resistance.
この発明の被覆ｃＢＮ基焼結工具は、硬質被覆層を上部層と下部層とで構成し、そして、硬質被覆層の上部層を薄層Ａと薄層Ｂの交互積層構造とし、さらに、ホーニング部については、そのホーニング面中央で、上部層の最外層を構成するＴｉＡｌＮ層の層厚を適正に確保し、一方、ホーニング面と逃げ面との稜線部においては、最外層のＴｉＡｌＮ層を除去し、薄層Ａと薄層Ｂの交互積層断面構造を露出形成させることによって、ホーニング面と逃げ面との稜線部においては特に強度を高め、それ以外の箇所（すくい面、逃げ面）では十分な耐摩耗性を確保していることから、合金工具鋼や軸受け鋼の焼入れ材などの高硬材の、高熱発生とともに切刃部に衝撃的・断続的な高負荷が作用する高速断続切削という厳しい切削条件下であっても、前記硬質被覆層に溶着、境界異常損傷、欠損の発生はなく、長期に亘って、すぐれた耐摩耗性を発揮することができる。 In the coated cBN-based sintered tool of the present invention, the hard coating layer is composed of an upper layer and a lower layer, and the upper layer of the hard coating layer is made of an alternately laminated structure of a thin layer A and a thin layer B. For the part, the thickness of the TiAlN layer that constitutes the outermost layer of the upper layer is appropriately secured at the center of the honing surface, while the outermost TiAlN layer is removed at the ridge line portion between the honing surface and the flank surface. In addition, by exposing the alternately laminated cross-sectional structure of the thin layer A and the thin layer B, the ridge line portion between the honing surface and the flank surface is particularly strong, and other portions (rake surface, flank surface) are sufficient. High-speed interrupted cutting, in which hard and hard materials such as hardened alloy tool steel and bearing steel are subjected to shock and intermittent high load on the cutting edge as heat is generated. Even under severe cutting conditions The welded hard layer, edge notching, no occurrence of defects, a long time, and can exhibit excellent wear resistance.
つぎに、この発明の被覆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、ＴｉＣＮ粉末、ＴｉＣ粉末、Ａｌ粉末、Ａｌ２Ｏ３粉末、ＷＣ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ＳＮＧＡ１２０４１２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0.2mmのチャンファーホーニング加工を施し、さらに刃先の稜線部をダイヤモンドブラシによって仕上げ研摩を施すことによりＩＳＯ規格ＳＮＧＡ１２０４１２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 raw material powders, cBN powder, TiN powder, TiCN powder, TiC powder, Al powder, Al 2 O 3 powder, and WC powder each having an average particle diameter in the range of 0.5 to 4 μm are prepared. Were mixed in the composition shown in Table 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. Then, the green compact is sintered in a vacuum atmosphere at a pressure of 1 Pa at a predetermined temperature in the range of 900 to 1300 ° C. for 60 minutes to obtain a presintered body for a cutting edge piece. In a state in which the ligated body is superposed on a separately prepared WC-based cemented carbide support piece having a size of Co: 8% by mass, WC: remaining composition, and diameter: 50 mm × thickness: 2 mm. The ultra-high pressure sintering equipment of The pressure is 4 GPa, the temperature is 1200 to 1400 ° C., the holding time is 0.8 hours, and the upper and lower surfaces are polished with a diamond grindstone after sintering. Then, it is divided into a regular triangle shape with a side of 3 mm by a wire electric discharge machine, and further Co: 5 mass%, TaC: 5 mass%, WC: remaining composition and shape of CIS standard SNGA120212 (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: After brazing with a brazing material of Ag alloy having the remaining composition, processing the outer periphery to a predetermined dimension, 0.2 mm chamfer honing is applied to the cutting edge, and the edge line of the cutting edge is further diamond By brush The tool bases A to J having the insert shape of ISO standard SNGA12041 were manufactured by finishing polishing.
（ａ）ついで、上記の工具基体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装置内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、一方側のカソード電極（蒸発源）として、表２に示される目標組成に対応した成分組成をもった下部層および薄層Ａ形成用Ｔｉ−Ａｌ合金を、また、他方側のカソード電極（蒸発源）として、上部層の薄層Ｂ形成用金属Ｔｉを前記回転テーブルを挟んで対向配置（なお、図１には示していないが、下部層と薄層Ａを異なった組成とする場合には、下部層形成用Ｔｉ−Ａｌ合金と薄層Ａ形成用Ｔｉ−Ａｌ合金の二種類のカソード電極（蒸発源）を配置する）し、
（ｂ）まず、装置内を排気して０．１Ｐａ以下の真空に保持しながら、ヒーターで装置内を５００℃に加熱した後、Ａｒガスを導入して、０．７Ｐａの雰囲気とすると共に、前記テーブル上で自転しながら回転する工具基体に−２００Ｖの直流バイアス電圧を印加し、もって工具基体表面をアルゴンイオンによってボンバード洗浄し、
（ｃ）装置内に反応ガスとして窒素ガスを導入して３Ｐａの反応雰囲気とすると共に、前記回転テーブル上で自転しながら回転する工具基体に−１００Ｖの直流バイアス電圧を印加し、かつ下部層形成用Ｔｉ−Ａｌ合金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の表面に、表２に示される目標組成および目標層厚の（Ｔｉ１−ＸＡｌＸ）Ｎ層を硬質被覆層の下部層として蒸着形成し、
（ｄ）ついで装置内に導入する反応ガスとしての窒素ガスの流量を調整して２Ｐａ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−１０〜−１００Ｖの範囲内の所定の直流バイアス電圧を印加した状態で、前記薄層Ｂ形成用金属Ｔｉのカソード電極とアノード電極との間に１００〜２００Ａの範囲内の所定の電流を流してアーク放電を発生させて、前記工具基体の表面に所定層厚のＴｉＮ層からなる薄層Ｂを形成した後、
（ｅ）ついで、同じく２Ｐａの窒素ガス反応雰囲気中で、薄層Ａ形成用Ｔｉ−Ａｌ合金のカソード電極とアノード電極間に同じく１００〜２００Ａの範囲内の所定の電流を流してアーク放電を発生させて、目標組成および目標層厚の（Ｔｉ１−ＸＡｌＸ）Ｎ層からなる薄層Ａを形成した後、
（ｆ）上記（ｄ）、（ｅ）を、所定の上部層合計層厚になるまで交互に繰り返し行い、最後に、（Ｔｉ１−ＸＡｌＸ）Ｎ層からなる最外層を所定層厚で形成し、もって前記工具基体の表面に、層厚方向に沿って表２に示される目標組成および一層目標層厚の薄層Ａと薄層Ｂの交互積層からなる上部層（但し、上部層の最外層はＴｉＡｌＮ層で構成する）を同じく表２に示される上部層合計層厚で蒸着形成した。
(A) Next, each of the tool bases A to J is ultrasonically cleaned in acetone and dried, and then in a radial direction from the central axis on the rotary table in the arc ion plating apparatus shown in FIG. And a thin layer A forming Ti having a component composition corresponding to the target composition shown in Table 2 as a cathode electrode (evaporation source) on one side at a predetermined distance away from the outer periphery. -Al alloy and the other side cathode electrode (evaporation source), the upper layer thin layer B forming metal Ti is placed opposite to the rotary table (not shown in FIG. When the layer and the thin layer A have different compositions, two types of cathode electrodes (evaporation source) of the Ti-Al alloy for forming the lower layer and the Ti-Al alloy for forming the thin layer A are arranged)
(B) First, while the inside of the apparatus is evacuated and kept at a vacuum of 0.1 Pa or less, the inside of the apparatus is heated to 500 ° C. with a heater, and then Ar gas is introduced to create an atmosphere of 0.7 Pa. A DC bias voltage of −200 V is applied to the tool base that rotates while rotating on the table, and the tool base surface is bombarded with argon ions.
(C) Nitrogen gas is introduced as a reaction gas into the apparatus to form a reaction atmosphere of 3 Pa, a DC bias voltage of −100 V is applied to the rotating tool base while rotating on the rotary table, and a lower layer is formed. An arc discharge is generated by flowing a current of 100 A between the Ti-Al alloy and the anode electrode, so that the target composition and target layer thickness (Ti 1-X Al) shown in Table 2 are formed on the surface of the tool base. X ) depositing the N layer as a lower layer of the hard coating layer,
(D) Next, the flow rate of nitrogen gas as a reaction gas introduced into the apparatus is adjusted to obtain a reaction atmosphere of 2 Pa, and within a range of −10 to −100 V on the tool base that rotates while rotating on the rotary table. With a predetermined DC bias voltage applied, a predetermined current within a range of 100 to 200 A is passed between the cathode electrode and the anode electrode of the thin layer B forming metal Ti to generate arc discharge, After forming a thin layer B composed of a TiN layer having a predetermined layer thickness on the surface of the tool base,
(E) Next, in a nitrogen gas reaction atmosphere of 2 Pa, arc discharge is generated by applying a predetermined current within the range of 100 to 200 A between the cathode electrode and the anode electrode of the Ti-Al alloy for forming the thin layer A. After forming the thin layer A composed of the (Ti 1-X Al X ) N layer having the target composition and the target layer thickness,
(F) The above steps (d) and (e) are repeated alternately until the predetermined upper layer total layer thickness is reached. Finally, the outermost layer composed of the (Ti 1-X Al X ) N layer is formed with the predetermined layer thickness. An upper layer (although the upper layer of the target composition shown in Table 2 along with the target composition and the alternate layer of the thin layer A and the thin layer B having a single target layer thickness) is formed on the surface of the tool base. The outermost layer was composed of a TiAlN layer) and was formed by vapor deposition with the total thickness of the upper layer shown in Table 2.
ついで、上記下部層および上部層からなる硬質被覆層を蒸着形成した工具基体について、すくい面に対して４３〜４７°の傾斜角で硬質被覆層にウエットブラスト処理（メディア：アルミナ粒子（粒径２０μｍ），ブラスト圧力：０．１ＭＰａ，ブラスト時間：１０ｓｅｃ，インサート回転速度：６０ｒｐｍ）を行い、ホーニング面と逃げ面との稜線部における最外層を除去し、該稜線部には、薄層Ａと薄層Ｂの交互積層断面構造を露出形成させることにより、表２に示す本発明被覆ｃＢＮ基焼結工具１〜１０をそれぞれ製造した。 Next, the tool base on which the hard coating layer composed of the lower layer and the upper layer was formed by vapor deposition was applied to the hard coating layer at a tilt angle of 43 to 47 ° with respect to the rake face (media: alumina particles (particle size 20 μm ), Blasting pressure: 0.1 MPa, blasting time: 10 sec, insert rotation speed: 60 rpm), and removing the outermost layer at the ridge line portion between the honing surface and the flank surface. By exposing and forming the alternately laminated cross-sectional structure of the layer B, the present invention coated cBN-based sintered tools 1 to 10 shown in Table 2 were produced.
比較の目的で、上記の工具基体Ａ〜Ｊのそれぞれに、本発明被覆ｃＢＮ基焼結工具１〜１０と同様な硬質被覆層を蒸着形成した従来被覆ｃＢＮ基焼結工具１〜１０をそれぞれ製造した。
つまり、従来被覆ｃＢＮ基焼結工具１〜１０では、ウエットブラスト処理を施さず、硬質被覆層の層厚は、逃げ面、すくい面、ホーニング面のいずれの面についても同一厚さであり、また、薄層Ａと薄層Ｂはいずれの箇所においても正に交互積層であって、交互積層断面構造が露出形成されている箇所はない。
For the purpose of comparison, conventional coated cBN-based sintered tools 1 to 10 in which hard coating layers similar to those of the present coated cBN-based sintered tools 1 to 10 are formed on the respective tool bases A to J are manufactured. did.
That is, in the conventional coated cBN-based sintered tools 1 to 10, wet blasting is not performed, and the layer thickness of the hard coating layer is the same for any of the flank, rake, and honing surfaces, The thin layer A and the thin layer B are positively and alternately laminated at any place, and there is no place where the alternately laminated cross-sectional structure is exposed.
参考のために、工具基体Ａ，Ｂを用いて、前記特許文献２に記載される構造の硬質被覆層を形成した。
すなわち、工具基体Ａに対しては、ＴｉＮ層の単層を層厚３μｍで被覆するとともに、ホーニング面と逃げ面の稜線部において、ウエットブラスト処理を施した参考被覆ｃＢＮ基焼結工具１を作製した。
また、工具基体Ｂに対しては、ＴｉＡｌＮ（Ｔｉ５０原子％−Ａｌ５０原子％）層の単層を層厚３μｍで被覆するとともに、ホーニング面と逃げ面の稜線部においては、ウエットブラスト処理を施した参考被覆ｃＢＮ基焼結工具２を作製した。
For reference, a hard coating layer having a structure described in Patent Document 2 was formed using the tool bases A and B.
That is, for the tool base A, a reference coated cBN-based sintered tool 1 is produced in which a single layer of TiN layer is coated with a layer thickness of 3 μm and wet blasting is performed on the ridgeline portions of the honing surface and the flank surface. did.
Further, for the tool base B, a single layer of TiAlN (Ti 50 atomic% -Al 50 atomic%) layer was coated with a layer thickness of 3 μm, and wet blasting was performed on the ridge line portions of the honing surface and the flank surface. A reference coated cBN-based sintered tool 2 was produced.
上記で作製した各被覆ｃＢＮ基焼結工具の表面被覆層について、その組成を透過型電子顕微鏡を用いてのエネルギー分散型Ｘ線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、また、その平均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 the surface coating layer of each coated cBN-based sintered tool produced above, the composition was measured by energy dispersive X-ray analysis using a transmission electron microscope. Moreover, when the average layer thickness was cross-sectional measured using a transmission electron microscope, all showed the average value (average value of five places) substantially the same as the target layer thickness.
つぎに、上記の各種の被覆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、従来被覆ｃＢＮ基焼結工具１〜１０および参考被覆ｃＢＮ基焼結工具１，２について、以下の切削条件Ａ〜Ｃで高速断続切削試験を実施した。
[切削条件Ａ]
被削材：ＪＩＳ・ＳＣＭ４２０（硬さ：ＨＲＣ６０）の長さ方向等間隔４本縦溝入り丸棒、
切削速度： ２５０ ｍ／ｍｉｎ．、
切り込み： ０．２ ｍｍ、
送り： ０．１１ ｍｍ／ｒｅｖ．、
切削時間： ８ 分、
の条件での浸炭焼入れ合金鋼の乾式高速断続切削加工試験（通常の切削速度は、１２０ｍ／ｍｉｎ．）、
[切削条件Ｂ]
被削材：ＪＩＳ・ＳＣｒ４２０（硬さ：ＨＲＣ６１）の長さ方向等間隔４本縦溝入り丸棒、
切削速度： ２７０ ｍ／ｍｉｎ．、
切り込み： ０．１６ ｍｍ、
送り： ０．１０ ｍｍ／ｒｅｖ．、
切削時間： ８ 分、
の条件での浸炭焼入れクロム鋼の乾式高速断続切削加工試験（通常の切削速度は、１２０ｍ／ｍｉｎ．）、
[切削条件Ｃ]
被削材：ＪＩＳ・ＳＵＪ２（硬さ：ＨＲＣ６１）の長さ方向等間隔４本縦溝入り丸棒、
切削速度： ２６０ ｍ／ｍｉｎ．、
切り込み： ０．２０ ｍｍ、
送り： ０．１１ ｍｍ／ｒｅｖ．、
切削時間： ８ 分、
の条件での焼入れ軸受鋼の乾式高速断続切削加工試験（通常の切削速度は、１２０ｍ／ｍｉｎ．）、
そして、上記の各切削加工試験における切刃の逃げ面摩耗幅（ｍｍ）を測定した。この測定結果を表４に示した。
Next, the above-mentioned various coated cBN-based sintered tools are screwed to the tip of the tool steel tool with a fixing jig, and the present coated cBN-based sintered tools 1 to 10, the conventional coated The cBN-based sintered tools 1 to 10 and the reference coated cBN-based sintered tools 1 and 2 were subjected to a high-speed intermittent cutting test under the following cutting conditions A to C.
[Cutting conditions A]
Work material: JIS SCM420 (Hardness: HRC60) lengthwise equidistantly 4 round bars with vertical grooves,
Cutting speed: 250 m / min. ,
Cutting depth: 0.2 mm,
Feed: 0.11 mm / rev. ,
Cutting time: 8 minutes,
Dry high-speed intermittent cutting test of carburized and quenched alloy steel under the conditions of (normal cutting speed is 120 m / min.),
[Cutting conditions B]
Work material: JIS · SCr420 (Hardness: HRC61) lengthwise equidistant four round grooved round bars,
Cutting speed: 270 m / min. ,
Cutting depth: 0.16 mm,
Feed: 0.10 mm / rev. ,
Cutting time: 8 minutes,
Dry high-speed intermittent cutting test of carburized and quenched chrome steel under the conditions of (normal cutting speed is 120 m / min.),
[Cutting conditions C]
Work material: JIS / SUJ2 (Hardness: HRC61) lengthwise equidistant four round grooved round bars,
Cutting speed: 260 m / min. ,
Cutting depth: 0.20 mm,
Feed: 0.11 mm / rev. ,
Cutting time: 8 minutes,
Dry high-speed intermittent cutting test of hardened bearing steel under the conditions of (normal cutting speed is 120 m / min.),
And the flank wear width (mm) of the cutting edge in each said cutting test was measured. The measurement results are shown in Table 4.
表２〜４に示される結果から、本発明被覆ｃＢＮ基焼結工具は、硬質被覆層が、下部層と、薄層Ａと薄層Ｂとの交互積層構造からなり、かつ、特に、ホーニング面と逃げ面との稜線部においては、最外層が存在せず、薄層Ａと薄層Ｂの交互積層断面構造が露出形成していることによって、硬質被覆層が全体としてすぐれた高温強度、高温硬さ、耐酸化性、靭性、耐衝撃性を備えているとともに、ホーニング面と逃げ面との稜線部においては、特に優れた耐溶着性、強度を有するために、合金工具鋼や軸受け鋼の焼入れ材などの高硬度材の高速断続切削に用いた場合であっても、切刃部からの硬質被覆層に剥離、境界異常損傷等の発生はなく、長期に亘って、すぐれた耐摩耗性を発揮する。
これに対して、ホーニング面と逃げ面との稜線部に交互積層断面構造が露出形成されていない従来被覆ｃＢＮ基焼結工具、あるいは、ホーニング面と逃げ面との稜線部において硬質被覆層が単層であり、交互積層膜が露出していない参考被覆ｃＢＮ基焼結工具においては、硬質被覆層の溶着、靭性、耐衝撃性不足等が原因で、刃先に剥離や境界異常損傷が発生し、比較的短時間で使用寿命に至ることが明らかである。
From the results shown in Tables 2 to 4, in the coated cBN-based sintered tool of the present invention, the hard coating layer is composed of an alternately laminated structure of the lower layer, the thin layer A, and the thin layer B, and in particular, the honing surface In the ridge line between the flank and the flank, the outermost layer does not exist, and the alternately laminated cross-sectional structure of the thin layer A and the thin layer B is exposed, so that the hard coating layer has excellent overall high-temperature strength and high temperature. In addition to hardness, oxidation resistance, toughness and impact resistance, the ridgeline between the honing surface and the flank surface has particularly excellent welding resistance and strength. Even when used for high-speed intermittent cutting of hardened materials such as hardened materials, there is no peeling or abnormal boundary damage on the hard coating layer from the cutting edge, and excellent wear resistance over a long period of time To demonstrate.
On the other hand, a conventional coated cBN-based sintered tool in which the alternately laminated cross-sectional structure is not exposed at the ridge line portion between the honing surface and the flank surface, or a hard coating layer is formed at the ridge line portion between the honing surface and the flank surface. In the reference coated cBN-based sintered tool that is a layer and the alternating laminated film is not exposed, due to welding of the hard coating layer, toughness, insufficient impact resistance, etc., peeling or abnormal boundary damage occurs on the cutting edge, It is clear that the service life is reached in a relatively short time.
上述のように、この発明の被覆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、特に合金工具鋼や軸受け鋼の焼入れ材などの高硬度材の高速断続切削であっても、前記硬質被覆層がホーニング面と逃げ面との稜線部においては、特に優れた耐溶着性と強度を有するために、長期に亘ってすぐれた切削性能を発揮するものであるから、切削加工装置の高性能化、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 high hardness such as hardened material of alloy tool steel and bearing steel, as well as cutting under normal cutting conditions such as various steels and cast iron. Even in high-speed intermittent cutting of materials, the hard coating layer has excellent welding resistance and strength especially at the ridgeline between the honing surface and the flank surface, so it exhibits excellent cutting performance over a long period of time. Therefore, it is possible to satisfactorily meet the demands for higher performance of the cutting device, labor saving and energy saving of the cutting, and cost reduction.
Claims (1)
（ａ）上記工具基体は、ホーニングの幅がすくい面方向からみて０．０３〜０．３ｍｍ、ホーニングの角度がすくい面とのなす角度で１０〜３５度の範囲にあるホーニング形状を有し、
（ｂ）上記硬質被覆層の下部層は、
組成式：（Ｔｉ１−ＸＡｌＸ）Ｎ
で表した場合、Ｘが０．３〜０．６（但し、原子比）である０．５〜４μｍの平均層厚を有するＴｉとＡｌの複合窒化物層からなり、
（ｃ）上記硬質被覆層の上部層は、それぞれ一層平均層厚が０．０３〜０．３μｍの薄層Ａと薄層Ｂの交互積層構造からなり、
上記薄層Ａは、上記ＴｉとＡｌの複合窒化物層、
上記薄層Ｂは、Ｔｉの窒化物層であり、
（ｄ）上記上部層の最外層は、ホーニング面と逃げ面との稜線部以外は平均層厚が０．１〜０．８μｍの上記ＴｉとＡｌの複合窒化物層で構成され、一方、ホーニング面と逃げ面との稜線部においては、上記最外層は存在せず上記薄層Ａと薄層Ｂの交互積層断面構造が露出形成され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。 Surface-coated cubic boron nitride formed by vapor-depositing a hard coating layer composed of a lower layer and an upper layer on the surface of a tool substrate made of a cubic boron nitride-based ultrahigh pressure sintered material containing 50 to 85 volume% of cubic boron nitride In a cutting tool made of a basic ultra-high pressure sintered material,
(A) The tool base has a honing shape in which the honing width is 0.03 to 0.3 mm when viewed from the rake face direction, and the honing angle is in the range of 10 to 35 degrees with respect to the rake face.
(B) The lower layer of the hard coating layer is
Composition formula: (Ti 1-X Al X ) N
X is 0.3 to 0.6 (provided that the atomic ratio) is composed of a composite nitride layer of Ti and Al having an average layer thickness of 0.5 to 4 μm,
(C) The upper layer of the hard coating layer is composed of an alternating laminated structure of thin layers A and B each having an average layer thickness of 0.03 to 0.3 μm,
The thin layer A is a composite nitride layer of Ti and Al,
The thin layer B is a Ti nitride layer,
(D) The outermost layer of the upper layer is composed of a composite nitride layer of Ti and Al having an average layer thickness of 0.1 to 0.8 μm except for the ridge line portion between the honing surface and the flank surface. The surface-coated cubic boron nitride group is characterized in that the outermost layer does not exist at the ridge line portion between the face and the flank face, and the alternately laminated sectional structure of the thin layer A and the thin layer B is exposed. Cutting tool made of ultra high pressure sintered material.
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| JP5838806B2 (en) * | 2011-12-28 | 2016-01-06 | 三菱マテリアル株式会社 | Surface coated cutting tool with excellent chipping resistance due to hard coating layer |
| CN106457411B (en) * | 2014-03-25 | 2018-12-11 | 兼房株式会社 | Cutting element |
| JP6198142B2 (en) * | 2014-03-26 | 2017-09-20 | 三菱マテリアル株式会社 | Cutting tool made of cubic boron nitride super high pressure sintered material |
| JP6507458B2 (en) * | 2016-02-24 | 2019-05-08 | 住友電工ハードメタル株式会社 | Method of manufacturing surface coated cutting tool |
| WO2018061408A1 (en) * | 2016-09-29 | 2018-04-05 | 住友電工ハードメタル株式会社 | Cutting tool |
| CN106676523B (en) * | 2016-11-24 | 2019-06-28 | 中南大学 | A kind of nano-composite coating hard alloy cutter with self-lubricating property |
| JP7227089B2 (en) * | 2019-06-28 | 2023-02-21 | 株式会社ダイヤメット | Materials used for forming cutting tools and their surface protective coatings |
| CN115198233A (en) * | 2022-06-22 | 2022-10-18 | 株洲瑞德尔智能装备有限公司 | Preparation method of PVD (physical vapor deposition) nano coating for die milling blade |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JPH11236671A (en) * | 1998-02-20 | 1999-08-31 | Mitsubishi Materials Corp | Throw away cutting tip made of surface-coated cemented carbide excellent in chipping resistance |
| JP3622846B2 (en) * | 2001-09-21 | 2005-02-23 | 住友電気工業株式会社 | Sticky milling tool |
| SE528108C2 (en) * | 2004-07-13 | 2006-09-05 | Sandvik Intellectual Property | Coated cemented carbide inserts, especially for turning steel, and ways of manufacturing the same |
| JP2008254159A (en) * | 2007-04-09 | 2008-10-23 | Mitsubishi Materials Corp | Surface-coated cutting tool made of cubic boron nitride group ultrahigh-pressure sintered material |
| JP2008302438A (en) * | 2007-06-05 | 2008-12-18 | Mitsubishi Materials Corp | Cutting tool made of surface coated cubic boron nitride-base very high pressure sintered material |
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| Publication number | Publication date |
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| JP2011121141A (en) | 2011-06-23 |
| CN102120268A (en) | 2011-07-13 |
| CN102120268B (en) | 2014-11-12 |
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