JP2008254159A - Surface-coated cutting tool made of cubic boron nitride group ultrahigh-pressure sintered material - Google Patents
Surface-coated cutting tool made of cubic boron nitride group ultrahigh-pressure sintered material Download PDFInfo
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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切削加工した場合でも、硬質被覆層がすぐれた耐摩耗性を有し、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 is capable of exhibiting stable cutting performance over a long period of time, even when high-hardness materials such as hardened materials of alloy tool steel and bearing steel are cut at high speed, and the hard coating layer has excellent wear resistance. A cutting tool made of a surface-coated cubic boron nitride-based ultra-high pressure sintered material (hereinafter referred to as coated cBN) in which a hard coating layer is formed on the surface of a cutting tool base made of a cubic boron nitride-based ultra-high pressure sintered material. (Referred to as a basic sintering 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（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、チタン窒化物層、チタンとアルミニウムの複合窒化物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。 The coated cBN-based sintered tool includes a titanium nitride layer, titanium on the surface of a tool body made of various cubic boron nitride-based ultrahigh pressure sintered materials (hereinafter referred to as cBN-based sintered materials). Coated cBN-based sintered tools formed by vapor-depositing a surface coating layer such as a composite nitride layer of aluminum and aluminum are known, and it is also known that these are used for cutting various steels and cast irons, for example. It has been.
さらに、上記の被覆ｃＢＮ基焼結工具が、例えば図２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上記の工具基体を装入し、ヒータで装置内を、例えば５００℃に加熱した状態で、金属Ｔｉあるいは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、たとえば−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、チタン窒化物層、チタンとアルミニウムの複合窒化物層など、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。
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、上記の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、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、切刃の逃げ面摩耗の発達が早くなり、被削材の寸法精度が悪化するか、あるいは、切刃の刃先の境界部分に異常損傷（以下、境界異常損傷という）を生じ、これが原因で被削材の仕上げ面精度が悪化し、いずれの場合においても、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 above-mentioned conventional coated tools, there is no particular problem when various types of steel and cast iron are machined under normal conditions. When used for high-speed cutting of hard materials such as hardened steel and bearing steel, the work material and chips are heated to a high temperature due to the high heat generated at the cutting edge. The dimensional accuracy of the work material deteriorates or the cutting edge of the cutting edge becomes abnormally damaged (hereinafter referred to as abnormal boundary damage), which causes the finished surface accuracy of the work material. In any case, The result in comparatively short time service life at present.
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切削加工で、硬質被覆層がすぐれた耐欠損性を発揮する被覆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。
(ａ) 硬質被覆層を構成するＴｉとＡｌの複合窒化物層（以下、ＴｉＡｌＮ層で示す）を、
組成式：（Ｔｉ１−ＸＡｌＸ）Ｎ
で表した場合、Ｔｉとの合量に占めるＡｌの含有割合Ｘ（原子比）の値が、０．４〜０．６５の範囲内において所定の高温硬さ、耐酸化性及び高温強度を有し、通常の切削加工条件下において必要とされる耐摩耗性は具備しているが、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は、切刃部に発生する高熱により被削材および切粉は極めて高温に加熱されるために、切刃の境界部分には境界異常損傷が生じ、そして、これが欠損の原因となること。
In view of the above, the present inventors, from the above viewpoint, have a coated cBN base that exhibits excellent fracture resistance with a hard coating layer in high-speed cutting of a hard material such as a hardened material of alloy tool steel or bearing steel. As a result of research to develop a sintered tool, the following findings were obtained.
(a) a Ti and Al composite nitride layer (hereinafter referred to as a TiAlN layer) constituting a hard coating layer;
Composition formula: (Ti 1-X Al X ) N
When the value of the Al content ratio X (atomic ratio) in the total amount with Ti is within the range of 0.4 to 0.65, it has predetermined high temperature hardness, oxidation resistance and high temperature strength. However, it has the wear resistance required under normal cutting conditions, but it occurs at the cutting edge in high-speed cutting of hard materials such as hardened materials of alloy tool steel and bearing steel. Since the work material and chips are heated to extremely high temperatures due to high heat, abnormal boundary damage occurs at the boundary part of the cutting edge, and this causes defects.
（ｂ）上記（ａ）のＴｉＡｌＮ層を硬質被覆層の下部層とし、その上に、チタンの窒化物（以下、ＴｉＮで示す）層を上部層として蒸着形成せしめ、ＴｉＮ層の具備するすぐれた靭性、耐衝撃性によって、硬質被覆層の境界異常損傷、欠損の発生を防止することも考えられるが、このような層構造では、耐境界異常損傷性、耐欠損性は改善されるものの、ＴｉＮ層は十分な高温硬さを備えていないために、硬質被覆層の耐摩耗性が低下するという不都合が生じること。 (B) The TiAlN layer of (a) was used as the lower layer of the hard coating layer, and a titanium nitride (hereinafter referred to as TiN) layer was deposited thereon as the upper layer, and the TiN layer was excellent. Although it is conceivable to prevent the occurrence of abnormal boundary damage and defects of the hard coating layer by toughness and impact resistance, such layer structure improves the abnormal boundary damage resistance and defect resistance, but TiN Since the layer does not have sufficient high temperature hardness, there arises a disadvantage that the wear resistance of the hard coating layer is lowered.
（ｃ）しかし、上記上部層を、すぐれた靭性、耐衝撃性を具備するＴｉＮ層と、すぐれた高温硬さ、高温強度を備えるＴｉ（ＣＹＮ１−Ｙ）層との交互積層構造として構成することにより、ＴｉＮ層の高温硬さの不足を補完し耐摩耗性を改善できる同時に、大きな発熱を伴う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、欠損の発生を防止できること。 (C) However, the upper layer is formed as an alternately laminated structure of a TiN layer having excellent toughness and impact resistance and a Ti (C Y N 1-Y ) layer having excellent high temperature hardness and high temperature strength. By configuring, it can compensate for the lack of high-temperature hardness of the TiN layer and improve wear resistance, and at the same time, boundary abnormalities in high-speed cutting of hard materials such as hardened alloy tool steel and bearing steel with large heat generation Can prevent damage and loss.
（ｄ）また、上記上部層の表面に、
組成式：（Ｔｉ１−ＺＡｌＺ）Ｎ
で表した場合、Ｔｉとの合量に占めるＡｌの含有割合Ｚ（原子比）の値が、０．４〜０．６５であるＴｉＡｌＮ層を最表面層として蒸着形成すると、ＴｉＡｌＮ層が、Ｔｉ（ＣＹＮ１−Ｙ）層とＴｉＮ層の交互積層の上に形成されることにより、このＴｉＡｌＮ層は（１１１）面に強配向したものとなり、耐チッピング性が著しく向上すること。
(D) Also, on the surface of the upper layer,
Formula: (Ti 1-Z Al Z ) N
When the TiAlN layer having an Al content ratio Z (atomic ratio) in the total amount with Ti of 0.4 to 0.65 is vapor-deposited as the outermost surface layer, the TiAlN layer becomes Ti The TiAlN layer is strongly oriented in the (111) plane by being formed on the (C Y N 1-Y ) layer and the TiN layer, and the chipping resistance is remarkably improved.
この発明は、上記知見に基づいてなされたものであって、
「（１） 窒化チタン（ＴｉＮ）、炭窒化チタン（ＴｉＣＮ）および炭化チタン（ＴｉＣ）のうちから選ばれる１種又は２種以上のチタン（Ｔｉ）化合物を３５〜５０％、アルミニウム（Ａｌ）および／または酸化アルミニウム（Ａｌ２Ｏ３）を８〜１６％、炭化タングステン（ＷＣ）を１〜６％、残部立方晶窒化ほう素（ｃＢＮ）（以上、％は、いずれも質量％を示す）からなる配合組成を有する圧粉体の超高圧焼結材料で構成され、かつ、走査型電子顕微鏡による組織観察で、分散相を形成する立方晶窒化ほう素（ｃＢＮ）相と連続相を形成するチタン（Ｔｉ）化合物相との界面に超高圧焼結反応生成物が介在した組織を有するインサート本体の表面に硬質被覆層を蒸着形成した表面被覆立方晶窒化ほう素（ｃＢＮ）基超高圧焼結材料製切削工具において、
（ａ）硬質被覆層は、０．５〜２μｍの平均層厚を有する下部層と、０．５〜３μｍの合計平均層厚を有する上部層とからなり、
（ｂ）硬質被覆層の下部層は、
組成式：（Ｔｉ１−ＸＡｌＸ）Ｎ
で表した場合、Ｘが０．４〜０．６５（但し、原子比）である蒸着形成されたチタンとアルミニウムの複合窒化物（ＴｉＡｌＮ）層、
（ｃ）硬質被覆層の上部層は、下部層の表面に蒸着形成された、一層平均層厚が０．０５〜０．３μｍの薄層Ａと、一層平均層厚が０．０２〜０．３μｍの薄層Ｂの交互積層構造を有し、
上記薄層Ａは、
組成式：ＴｉＮで表されるチタンの窒化物（ＴｉＮ）層、
上記薄層Ｂは、
組成式：Ｔｉ（ＣＹＮ１−Ｙ）
で表した場合、Ｙが０．１〜０．７（但し、原子比）であるチタンの炭窒化物（ＴｉＣＮ）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（ｃＢＮ）基超高圧焼結材料製切削工具（被覆ｃＢＮ基焼結工具）。
（２） 前記（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おいて、上記上部層の表面に、
組成式：（Ｔｉ１−ＺＡｌＺ）Ｎ
で表した場合、Ｚが０．４〜０．６５（但し、原子比）であるチタンとアルミニウムの複合窒化物層（ＴｉＡｌＮ）からなる最表面層を、０．２〜１．５μｍの平均層厚で蒸着形成した、前記（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。
This invention has been made based on the above findings,
“(1) 35 to 50% of one or more titanium (Ti) compounds selected from titanium nitride (TiN), titanium carbonitride (TiCN) and titanium carbide (TiC), aluminum (Al) and / Or from aluminum oxide (Al 2 O 3 ) 8-16%, tungsten carbide (WC) 1-6%, balance cubic boron nitride (cBN) (above,% indicates mass%) Titanium comprising a cubic boron nitride (cBN) phase forming a disperse phase and a continuous phase formed by observation of the structure with a scanning electron microscope. (Ti) Surface-coated cubic boron nitride (cBN) -based ultrahigh-pressure sintered material in which a hard coating layer is deposited on the surface of an insert body having a structure in which an ultrahigh-pressure sintered reaction product is interposed at the interface with the compound phase In the cutting tool,
(A) The hard coating layer consists of a lower layer having an average layer thickness of 0.5 to 2 μm and an upper layer having a total average layer thickness of 0.5 to 3 μm,
(B) The lower layer of the hard coating layer is
Composition formula: (Ti 1-X Al X ) N
, A composite nitride (TiAlN) layer of titanium and aluminum formed by vapor deposition with X of 0.4 to 0.65 (however, atomic ratio),
(C) The upper layer of the hard coating layer is formed by vapor deposition on the surface of the lower layer, the thin layer A having an average layer thickness of 0.05 to 0.3 μm, and the average layer thickness of 0.02 to 0.03. It has an alternately laminated structure of 3 μm thin layers B,
The thin layer A is
Composition formula: titanium nitride (TiN) layer represented by TiN,
The thin layer B is
Composition formula: Ti (C Y N 1-Y )
, A titanium carbonitride (TiCN) layer having a Y of 0.1 to 0.7 (atomic ratio),
A surface-coated cubic boron nitride (cBN) -based ultrahigh-pressure sintered material cutting tool (coated cBN-based sintered tool) in which a hard coating layer made of is vapor-deposited.
(2) In the surface-coated cubic boron nitride-based ultrahigh pressure sintered material cutting tool described in (1) above, on the surface of the upper layer,
Formula: (Ti 1-Z Al Z ) N
The outermost surface layer made of a composite nitride layer of titanium and aluminum (TiAlN) having a Z of 0.4 to 0.65 (however, atomic ratio) is an average layer of 0.2 to 1.5 μm. The surface-coated cubic boron nitride-based ultrahigh pressure sintered material cutting tool according to (1), which is formed by vapor deposition. "
It has the characteristics.
つぎに、この発明の被覆ｃＢＮ基焼結工具において、これを構成するインサート本体のｃＢＮ基焼結材料の配合組成および硬質被覆層の組成、層厚を限定した理由を説明する。
（ａ）インサート本体のｃＢＮ基焼結材料の配合組成
（イ）ＴｉＮ、ＴｉＣＮおよびＴｉＣのうちから選ばれる１種又は２種以上のＴｉ化合物
焼結材料中のＴｉ化合物成分は、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３５質量％未満で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５０質量％を超えると相対的に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、その配合割合を３５〜５０質量％と定めた。
Next, in the coated cBN-based sintered tool of the present invention, the reason why the composition of the cBN-based sintered material of the insert main body, the composition of the hard coating layer, and the layer thickness are limited will be described.
(A) Mixing composition of cBN-based sintered material of insert body (A) One or more Ti compounds selected from TiN, TiCN and TiC Ti compound component in sintered material has sinterability While improving the strength and improving the strength by forming a continuous phase in the sintered body, if the blending ratio is less than 35% by mass, the desired strength cannot be ensured, while the blending ratio is 50% by mass. When the content exceeds 50%, the content of cBN is relatively reduced, and rake face wear and the like are likely to occur. Therefore, the blending ratio was determined to be 35 to 50% by mass.
（ロ）Ａｌおよび／またはＡｌ２Ｏ３
これらの成分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し、この結果切刃の耐チッピング性が向上するようになるが、Ａｌおよび／またはＡｌ２Ｏ３の配合割合が８〜１６質量％の範囲からはずれると、中間密着層として前記硬質分散相と連続相の間に強固な密着性を確保することができないので、Ａｌおよび／またはＡｌ２Ｏ３の配合割合を８〜１６質量％と定めた。
(B) Al and / or Al 2 O 3
These components are preferentially aggregated on the surface of the cBN powder during the sintering and react to form a reaction product. In the sintered cBN-based material, the Ti compound phase and the hard dispersed phase form a continuous phase. This reaction product has a property of tightly bonding and bonding with both the Ti compound phase forming the continuous phase and the cBN phase forming the hard dispersed phase. , The adhesion of the cBN phase to the Ti compound phase which is a continuous bonded phase is remarkably improved. As a result, the chipping resistance of the cutting edge is improved, but the blending ratio of Al and / or Al 2 O 3 is 8 If it is out of the range of ˜16% by mass, it is not possible to ensure strong adhesion between the hard dispersed phase and the continuous phase as an intermediate adhesion layer, so the blending ratio of Al and / or Al 2 O 3 is 8 to 16% by mass It determined.
（ハ）ＷＣ
結合相の主成分であるＴｉ化合物とｃＢＮが焼結時に反応を起こすと、ＴｉＢ２という硬いが脆い化合物が生成する。そのため、ＴｉＢ２が多く生成すると、切刃のチッピングが生じやすくなる。ＷＣを添加すると、ｃＢＮ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が期待できる。ＷＣ添加量が１％未満では、ＴｉＢ２の生成を十分に抑制できず、逆に、６％を超えて添加すると、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の配合割合を１〜６質量％と定めた。
(C) WC
When the Ti compound, which is the main component of the binder phase, reacts with cBN during sintering, a hard but brittle compound called TiB 2 is generated. Therefore, when a large amount of TiB 2 is generated, chipping of the cutting edge is likely to occur. When WC is added, a boride of W is generated in the vicinity of cBN and the generation of TiB 2 is suppressed, so that an improvement in chipping resistance can be expected. If the amount of WC added is less than 1%, the formation of TiB 2 cannot be sufficiently suppressed. Conversely, if added over 6%, the WC component remains and conversely causes a reduction in chipping resistance. Of 1 to 6% by mass was determined.
（ニ）ｃＢＮ
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、焼結材料の構成成分であるＴｉ化合物、Ａｌおよび／またはＡｌ２Ｏ３の残部、ＷＣの残部、即ち、２８〜５６質量％となる。
(D) cBN
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 blending ratio of Ti is the remaining Ti compound, Al and / or Al 2 O 3 and the remaining WC, that is, 28 to 56% by mass, which is a constituent component of the sintered material.
（ｂ）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、Ａｌの含有割合Ｘが６５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４０原子％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Ｘの値を０．４〜０．６５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、一方その平均層厚が２μｍ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０．５〜２μｍと定めた。
(B) Lower layer of 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 oxidation resistance. The (Ti 1-X Al X ) N layer constituting the lower layer is a layer having predetermined high-temperature strength, high-temperature hardness and heat resistance, and is a high-hardness material such as a hardened material of alloy tool steel or bearing steel. It basically plays the role of ensuring the wear resistance of the cutting edge during high-speed cutting. However, if the Al content ratio X exceeds 65 atomic%, the high-temperature strength decreases due to the change in the crystal structure, and defects tend to occur. On the other hand, if the Al content ratio X is less than 40 atomic%, Since the heat resistance is lowered and as a result, the wear resistance is lowered, the value of the Al content ratio X is set to 0.4 to 0.65.
In addition, if the average thickness of the lower layer is less than 0.5 μm, the heat 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 layer thickness exceeds 2 μm, defects tend to occur, so the average layer thickness was set to 0.5 to 2 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チタンまたはクロムの窒化物（ＴｉＮまたはＣｒＮ）の薄層を介在させることができる。該ＴｉＮまたはＣｒＮの薄層は、その層厚が０．０１μｍ未満では密着性改善の効果が少なく、一方、０．５μｍを超えた層厚としても密着性の更なる向上が期待できるわけではないことから、基体と下部層との間に介在させるＴｉＮ層またはＣｒＮ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 titanium or chromium nitride (TiN or CrN) is interposed between the base and the lower layer in order to ensure sufficient adhesion between the cutting tool base made of ultra-high pressure sintered material and the lower layer. Can be made. The thin layer of TiN or CrN has little effect of improving the adhesion when the layer thickness is less than 0.01 μm, while further improvement of the adhesion cannot be expected even when the layer thickness exceeds 0.5 μm. Therefore, the thickness of the TiN layer or CrN interposed between the substrate and the lower layer is preferably 0.01 μm or more and 0.5 μm or less.
（ｃ）硬質被覆層の上部層
（イ）上部層の薄層Ａ
上部層の薄層Ａを構成するＴｉＮ層は、所定の靭性、耐衝撃性を備えるため、高硬度材の高速切削加工時において、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０．０５μｍ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Ａの一層平均層厚は、０．０５〜０．３μｍと定めた。
(C) Upper layer of hard coating layer (b) Thin layer A of upper layer
Since the TiN layer constituting the thin layer A of the upper layer has predetermined toughness and impact resistance, it prevents the occurrence of abnormal boundary damage or chipping in the hard coating layer during high-speed cutting of a hard material. However, if the average layer thickness is less than 0.05 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 A was determined to be 0.05 to 0.3 μm.
（ロ）上部層の薄層Ｂ
上部層の薄層Ｂを構成するＴｉＣＮ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Ａの有する靭性、耐衝撃性を損なうことなしに、薄層Ａに不足する特性（高温硬さ）を補完することができる。
つまり、薄層Ｂを構成するＴｉＣＮ層を、
組成式：Ｔｉ（ＣＹＮ１−Ｙ）
で表した場合、Ｃ成分には層の硬さを向上させ、Ｎ成分には層の強度を向上させる作用があるが、層中のＣ成分の含有割合（Ｙ値。但し、原子比）が０．１未満であると、ＴｉＣＮ層の高温硬さの向上を期待することはできず、一方、層中のＣ成分の含有割合（Ｙ値）が０．７を超えると、高温硬さは大になるが、相対的なＮ成分の含有割合の減少により、層の靭性、耐衝撃性が低下し、チッピングを発生しやすくなるので、層中のＣ成分の含有割合（Ｙ値）を０．１〜０．７と定めた。
上部層の薄層Ａは、すでに述べたように、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、すぐれた高温硬さを備えた上記薄層Ｂを薄層A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Ａ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Ｂの一層平均層厚が０．０２μｍ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Ｂの一層平均層厚は、０．０２〜０．３μｍと定めた。
(B) Upper layer thin layer B
The TiCN layer constituting the thin layer B of the upper layer is composed of the thin layer A and the thin layer B so that the thin layer A can be formed without impairing the toughness and impact resistance of the thin layer A. The properties (high temperature hardness) that are insufficient can be supplemented.
That is, the TiCN layer constituting the thin layer B is
Composition formula: Ti (C Y N 1-Y )
, The C component has the effect of improving the hardness of the layer and the N component has the effect of improving the strength of the layer, but the content ratio of the C component in the layer (Y value, where the atomic ratio) is If it is less than 0.1, improvement in the high temperature hardness of the TiCN layer cannot be expected. On the other hand, if the content ratio (Y value) of the C component in the layer exceeds 0.7, the high temperature hardness is However, since the toughness and impact resistance of the layer are lowered and chipping is likely to occur due to the relative decrease in the content ratio of the N component, the content ratio (Y value) of the C component in the layer is reduced to 0. .1 to 0.7.
As described above, the thin layer A of the upper layer is a layer having predetermined toughness and impact resistance, and suppresses abnormal boundary damage and chipping during high-speed cutting of a hard material, On the other hand, wear resistance is likely to deteriorate due to lack of high-temperature hardness, so the above-mentioned thin layer B with excellent high-temperature hardness is alternately laminated with thin layer A to compensate for lack of high-temperature hardness. In addition, the high temperature hardness, toughness, and impact resistance are ensured as the entire upper layer composed of the alternately laminated structure without deteriorating the characteristics of the thin layer A. If the thickness is less than 0.02 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 is likely to occur. The thickness was determined to be 0.02 to 0.3 μm.
（ハ）上部層の薄層Ａと薄層Ｂの一層平均層厚、上部層の平均層厚
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、０．５μｍ未満では、高硬度材の高速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０．５〜３μｍと定めた。
(C) Upper layer thin layer A and thin layer B one layer average layer thickness, upper layer average layer thickness The upper layer consisting of the alternating layered structure of thin layer A and thin layer B has a total average layer thickness of 0 When the thickness is less than 5 μm, sufficient toughness and impact resistance required for high-speed cutting of a hard material cannot be exhibited. On the other hand, when the average layer thickness exceeds 3 μm, defects are likely to occur. Therefore, the average layer thickness was determined to be 0.5 to 3 μm.
また、この発明の被覆ｃＢＮ基焼結工具では、上部層の表面に、さらに、
組成式：（Ｔｉ１−ＺＡｌＺ）Ｎ
で表した場合、Ｚが０．４〜０．６５（但し、原子比）であるＴｉＡｌＮ層からなる最表面層を、０．２〜１．５μｍの平均層厚で蒸着形成することができるが、この場合、層厚が０．２μｍ未満では耐チッピング性向上に対して効果がみられず、一方、その層厚が１．５μｍを超えると、全体としての層厚が厚くなりすぎるためにかえってチッピングを生じやすくなることから、その平均層厚を０．２〜１．５μｍと定めた。
In the coated cBN-based sintered tool of the present invention, on the surface of the upper layer,
Formula: (Ti 1-Z Al Z ) N
In this case, the outermost surface layer composed of a TiAlN layer having a Z of 0.4 to 0.65 (however, atomic ratio) can be formed by vapor deposition with an average layer thickness of 0.2 to 1.5 μm. In this case, if the layer thickness is less than 0.2 μm, no effect is seen in improving chipping resistance. On the other hand, if the layer thickness exceeds 1.5 μm, the overall layer thickness becomes too thick. Since the chipping tends to occur, the average layer thickness is set to 0.2 to 1.5 μm.
なお、この発明の被覆ｃＢＮ基焼結工具基体の表面粗度は、Ｒａで０．０５以上１．０以下であることが望ましい。表面粗度Ｒａが０．０５以上であれば、アンカー効果による基体と硬質被覆層の下部層との付着強度の向上が期待でき、一方、Ｒａが１．０を超えるようになると、被削材の仕上げ面精度に悪影響を及ぼすようになるためである。 The surface roughness of the coated cBN-based sintered tool base according to the present invention is preferably 0.05 to 1.0 in terms of Ra. If the surface roughness Ra is 0.05 or more, an improvement in adhesion strength between the base body and the lower layer of the hard coating layer can be expected due to the anchor effect. On the other hand, if Ra exceeds 1.0, the work material This is because it will adversely affect the finished surface accuracy.
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、あるいは、さらに、最表面層を設け、そして、硬質被覆層の上部層を薄層Ａと薄層Ｂの交互積層構造とすることによって特にすぐれた高温硬さ、靭性、耐衝撃性を兼ね備え、合金工具鋼や軸受け鋼の焼入れ材などの高硬材の、高熱発生を伴う高速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, or an outermost surface layer is provided, and the upper layer of the hard coating layer is formed of a thin layer A and a thin layer. The alternating layered structure of B has excellent high-temperature hardness, toughness, and impact resistance, and severe cutting conditions such as high-speed cutting with high heat generation of hard materials such as hardened alloy tool steel and bearing steel. Even underneath, there is no occurrence of abnormal boundary damage or defects in the hard coating layer, and excellent wear resistance can be exhibited over a long period of time.
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: 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 °. To finish polishing Further, tool bases A to J each having an insert shape of ISO standard SNGA12041 were manufactured.
（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、上部層の薄層Ａ、薄層Ｂ形成用金属Ｔｉを、また、他方側のカソード電極（蒸発源）として、それぞれ表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形成用Ｔｉ−Ａｌ合金を前記回転テーブルを挟んで対向配置し、
（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Ａ、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５０〜２００Ａ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Ａを形成し、前記薄層Ａ形成後、アーク放電を停止し、反応ガスとしての窒素ガス、メタンの流量を調整して２．７Ｐａの反応雰囲気とすると共に、前記薄層Ａ、薄層Ｂ形成用金属Ｔｉのカソード電極とアノード電極間に同じく５０〜２００Ａ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、所定層厚のＴｉ（ＣＹＮ１−Ｙ）層からなる薄層Ｂを形成した後、アーク放電を停止し、その後、薄層Ａと薄層Ｂの形成を交互に繰り返し行い、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を同じく表２に示される合計平均層厚で蒸着形成することにより、本発明被覆ｃＢＮ基焼結工具１〜６をそれぞれ製造した。
また、上記以外の本発明被覆ｃＢＮ基焼結工具については、前記（ｃ）と同手順により、蒸着形成した上部層の表面にさらに、表２に示される目標組成および目標層厚の最表面層を蒸着形成することにより、本発明被覆ｃＢＮ基焼結工具７〜１０をそれぞれ製造した。
(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. Are mounted along the outer periphery at a predetermined distance from each other, and the upper layer thin layer A and the thin layer B forming metal Ti are used as one side cathode electrode (evaporation source), and the other side cathode electrode ( As an evaporation source), Ti-Al alloys for forming a lower layer each having a component composition corresponding to the target composition shown in Table 2 are arranged to face each other with the rotary table interposed therebetween,
(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. In a state in which a predetermined DC bias voltage is applied, a predetermined current in the range of 50 to 200 A is passed between the cathode electrode and the anode electrode of the metal Ti for forming the thin layer A and the thin layer B to cause arc discharge. To form a thin layer A composed of a TiN layer having a predetermined thickness on the surface of the tool base. After the thin layer A is formed, the arc discharge is stopped and the flow rates of nitrogen gas and methane as reaction gases are adjusted. The reaction atmosphere is set to 2.7 Pa, and a predetermined current in the range of 50 to 200 A is applied between the cathode electrode and the anode electrode of the metal Ti for forming the thin layer A and the thin layer B to generate arc discharge. The Te after forming the thin layer B having a predetermined layer thickness of the Ti (C Y N 1-Y ) layer, the arc discharge is stopped, then repeated alternately to form the thin layer A and the thin layer B, has been On the surface of the tool base, an upper average layer composed of alternating layers of the thin layer A and the thin layer B having the target composition shown in Table 2 along the layer thickness direction and a single target layer thickness is also shown in Table 2. The coated cBN-based sintered tools 1 to 6 of the present invention were manufactured by vapor deposition with a thickness.
For the coated cBN-based sintered tool of the present invention other than those described above, the outermost surface layer having the target composition and target layer thickness shown in Table 2 is further formed on the surface of the upper layer formed by vapor deposition according to the same procedure as in (c). The present invention coated cBN-based sintered tools 7 to 10 were produced respectively by vapor deposition.
また、比較の目的で、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２に示される通常のアークイオンプレーティング装置に装入し、カソード電極（蒸発源）として、それぞれ表３に示される目標組成に対応した成分組成をもったＴｉ−Ａｌ合金を装着し、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、ついで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、前記工具基体に印加するバイアス電圧を−１００Ｖに下げて、前記Ｔｉ−Ａｌ合金のカソード電極とアノード電極との間にアーク放電を発生させ、もって前記工具基体Ａ〜Ｊのそれぞれの表面に、表３に示される目標組成および目標層厚のＴｉＡｌＮ層からなる硬質被覆層を蒸着形成することにより、従来被覆ｃＢＮ基焼結工具１〜１０をそれぞれ製造した。 For comparison purposes, each of the tool bases A to J described above is ultrasonically cleaned in acetone and dried, and then charged into a normal arc ion plating apparatus shown in FIG. As the (evaporation source), a Ti—Al alloy having a component composition corresponding to the target composition shown in Table 3 was mounted. First, the apparatus was evacuated and kept at a vacuum of 0.1 Pa or less while heating. After heating the inside of the apparatus to 500 ° C., Ar gas is introduced to make an atmosphere of 0.7 Pa, and a DC bias voltage of −200 V is applied to the tool base that rotates while rotating on the table. The tool substrate surface is bombarded with argon ions, and then nitrogen gas is introduced into the apparatus as a reaction gas to form a reaction atmosphere of 3 Pa, and a via applied to the tool substrate. The voltage was lowered to −100 V to generate an arc discharge between the cathode electrode and the anode electrode of the Ti—Al alloy, and the target composition shown in Table 3 and the surface of each of the tool substrates A to J were Conventionally coated cBN-based sintered tools 1 to 10 were produced by vapor-depositing a hard coating layer composed of a TiAlN layer having a target layer thickness.
この結果得られた各種の被覆ｃＢＮ基焼結工具のインサート本体を構成するｃＢＮ基焼結材料について、その組織を走査型電子顕微鏡を用いて観察したところ、いずれのインサート本体も、実質的に分散相を形成するｃＢＮ相と連続相を形成するＴｉＮ相、ＴｉＣＮ相、ＴｉＣ相との界面に超高圧焼結反応生成物が介在した組織を示した。 Regarding the cBN-based sintered material constituting the insert body of various coated cBN-based sintered tools obtained as a result, the structure was observed using a scanning electron microscope, and all the insert bodies were substantially dispersed. A structure in which an ultrahigh-pressure sintering reaction product was present at the interface between the cBN phase forming the phase and the TiN phase, TiCN phase, and TiC phase forming the continuous phase was shown.
さらに、同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。 Further, when the composition of the surface coating layer was measured by energy dispersive X-ray analysis using a transmission electron microscope, the composition showed substantially the same composition as the target composition, and the average layer thickness was When the cross section was 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および従来被覆ｃＢＮ基焼結工具１〜１０ついて、以下に示す切削条件Ａ〜Ｃで高速連続切削試験を実施した。
[切削条件Ａ]
被削材：ＪＩＳ・ＳＣＭ４２０（硬さ：ＨＲＣ６０）の丸棒、
切削速度： ２６０ ｍ／ｍｉｎ．、
切り込み： ０．１５ ｍｍ、
送り： ０．１５ ｍｍ／ｒｅｖ．、
切削時間： ５ 分、
の条件での浸炭焼入れ合金鋼の乾式連続高速切削加工試験（通常の切削速度は１６０ｍ／ｍｉｎ．）、
[切削条件Ｂ]
被削材：ＪＩＳ・ＳＣｒ４２０（硬さ：ＨＲＣ６１）の丸棒、
切削速度： ２４０ ｍ／ｍｉｎ．、
切り込み： ０．１２ ｍｍ、
送り： ０．１２ ｍｍ／ｒｅｖ．、
切削時間： ６ 分、
の条件での浸炭焼入れクロム鋼の乾式連続高速切削加工試験（通常の切削速度は１６０ｍ／ｍｉｎ．）、
[切削条件Ｃ]
被削材：ＪＩＳ・ＳＵＪ２（硬さ：ＨＲＣ６１）の丸棒、
切削速度： ２５０ ｍ／ｍｉｎ．、
切り込み： ０．１２ ｍｍ、
送り： ０．１０ ｍｍ／ｒｅｖ．、
切削時間： ４ 分、
の条件での焼入れ軸受鋼の乾式連続高速切削加工試験（通常の切削速度は１５０ｍ／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, according to the present invention, the coated cBN-based sintered tools 1 to 10 and the conventional coated cBN-based sintered tool, in a state where all the above-mentioned coated cBN-based sintered tools are screwed to the tip of the tool steel tool with a fixing jig The cBN-based sintered tools 1 to 10 were subjected to a high-speed continuous cutting test under the following cutting conditions A to C.
[Cutting conditions A]
Work material: JIS / SCM420 (Hardness: HRC60) round bar,
Cutting speed: 260 m / min. ,
Cutting depth: 0.15 mm,
Feed: 0.15 mm / rev. ,
Cutting time: 5 minutes,
Dry continuous high-speed cutting test of carburized and quenched alloy steel under the conditions of (normal cutting speed is 160 m / min.),
[Cutting conditions B]
Work material: JIS · SCr420 (hardness: HRC61) round bar,
Cutting speed: 240 m / min. ,
Cutting depth: 0.12 mm,
Feed: 0.12 mm / rev. ,
Cutting time: 6 minutes,
Dry continuous high-speed cutting test of carburized and quenched chrome steel under the conditions of (normal cutting speed is 160 m / min.),
[Cutting conditions C]
Work material: JIS / SUJ2 (Hardness: HRC61) round bar,
Cutting speed: 250 m / min. ,
Cutting depth: 0.12 mm,
Feed: 0.10 mm / rev. ,
Cutting time: 4 minutes,
Dry continuous high-speed cutting test of hardened bearing steel under the conditions (normal cutting speed is 150 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、いずれも硬質被覆層が、０．５〜２μｍの平均層厚を有する下部層と、一層平均層厚が０．０５〜０．３μｍの薄層Ａと一層平均層厚が０．０２〜０．３μｍの薄層Ｂの交互積層構造の合計平均層厚０．５〜３μｍの上部層とからなり、あるいは、さらに０．２〜１．５μｍの平均層厚を有する最表面層とからなり、前記下部層がすぐれた高温強度、高温硬さおよび耐熱性を備え、前記上部層がすぐれた高温硬さ、靭性、耐衝撃性を備え、さらに、前記最表面層がすぐれた耐チッピング性を備えているので、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に用いた場合であっても、前記硬質被覆層に境界異常損傷、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のに対して、硬質被覆層が単一のＴｉＡｌＮ層からなる従来被覆ｃＢＮ基焼結工具は、特に硬質被覆層の靭性、耐衝撃性不足が原因で、刃先に境界異常損傷や欠損が発生し、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, the coated cBN-based sintered tool of the present invention has a hard coating layer, a lower layer having an average layer thickness of 0.5 to 2 μm, and an average layer thickness of 0.05. It is composed of an upper layer having a total average layer thickness of 0.5 to 3 μm of an alternating laminated structure of a thin layer A having a thickness of ˜0.3 μm and a thin layer B having an average layer thickness of 0.02 to 0.3 μm. The outermost layer having an average layer thickness of 2 to 1.5 μm, wherein the lower layer has excellent high temperature strength, high temperature hardness and heat resistance, and the upper layer has excellent high temperature hardness, toughness and resistance to heat. Even if it is used for high-speed cutting of hard materials such as hardened materials of alloy tool steel and bearing steel, the outermost surface layer has excellent chipping resistance. There is no abnormal boundary damage or chipping in the hard coating layer, and excellent wear resistance over a long period of time In contrast, conventional coated cBN-based sintered tools with a hard coating layer consisting of a single TiAlN layer, especially due to the lack of toughness and impact resistance of the hard coating layer, cause abnormal edge damage and defects 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切削であっても、前記硬質被覆層がすぐれた耐境界異常損傷性、耐欠損性を発揮し、長期に亘ってすぐれた耐摩耗性をも示すものであるから、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 cutting of materials, the hard coating layer exhibits excellent boundary abnormal damage resistance and fracture resistance, and also exhibits excellent wear resistance over a long period of time. It can sufficiently satisfy high performance, labor saving and energy saving of cutting, and cost reduction.
Claims (2)
（ａ）硬質被覆層は、０．５〜２μｍの平均層厚を有する下部層と、０．５〜３μｍの合計平均層厚を有する上部層を有し、
（ｂ）硬質被覆層の下部層は、
組成式：（Ｔｉ１−ＸＡｌＸ）Ｎ
で表した場合、Ｘが０．４〜０．６５（但し、原子比）である蒸着形成されたチタンとアルミニウムの複合窒化物層、
（ｃ）硬質被覆層の上部層は、下部層の表面に蒸着形成された、一層平均層厚が０．０５〜０．３μｍの薄層Ａと、一層平均層厚が０．０２〜０．３μｍの薄層Ｂの交互積層構造を有し、
上記薄層Ａは、
組成式：ＴｉＮで表されるチタンの窒化物層、
上記薄層Ｂは、
組成式：Ｔｉ（ＣＹＮ１−Ｙ）
で表した場合、Ｙが０．１〜０．７（但し、原子比）であるチタンの炭窒化物層、
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。 35 to 50% of one or more titanium compounds selected from titanium nitride, titanium carbonitride and titanium carbide, 8 to 16% of aluminum and / or aluminum oxide, 1 to 6% of tungsten carbide, the balance It is composed of an ultra-high pressure sintered material of a green compact having a blended composition consisting of cubic boron nitride (wherein% represents mass%), and the dispersed phase is observed by microstructure observation with a scanning electron microscope. Surface-coated cubic with a hard coating layer deposited on the surface of the insert body having a structure in which an ultrahigh-pressure sintering reaction product is present at the interface between the cubic boron nitride phase forming the titanium and the titanium compound phase forming the continuous phase In the cutting tool made of crystal boron nitride based ultra high pressure sintered material,
(A) The hard coating layer has a lower layer having an average layer thickness of 0.5 to 2 μm and an upper layer having a total average layer thickness of 0.5 to 3 μm,
(B) The lower layer of the hard coating layer is
Composition formula: (Ti 1-X Al X ) N
, A composite nitride layer of titanium and aluminum formed by vapor deposition with X being 0.4 to 0.65 (however, atomic ratio),
(C) The upper layer of the hard coating layer is formed by vapor deposition on the surface of the lower layer, the thin layer A having an average layer thickness of 0.05 to 0.3 μm, and the average layer thickness of 0.02 to 0.03. It has an alternately laminated structure of 3 μm thin layers B,
The thin layer A is
Composition formula: a nitride layer of titanium represented by TiN,
The thin layer B is
Composition formula: Ti (C Y N 1-Y )
, A carbonitride layer of titanium in which Y is 0.1 to 0.7 (wherein the atomic ratio),
A cutting tool made of a surface-coated cubic boron nitride-based ultra-high pressure sintered material formed by vapor-depositing a hard coating layer comprising:
組成式：（Ｔｉ１−ＺＡｌＺ）Ｎ
で表した場合、Ｚが０．４〜０．６５（但し、原子比）であるチタンとアルミニウムの複合窒化物層からなる最表面層を、０．２〜１．５μｍの平均層厚で蒸着形成した、請求項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。 In the surface-coated cubic boron nitride-based ultra-high pressure sintered material cutting tool according to claim 1, on the surface of the upper layer,
Formula: (Ti 1-Z Al Z ) N
The outermost surface layer composed of a composite nitride layer of titanium and aluminum whose Z is 0.4 to 0.65 (however, atomic ratio) is deposited with an average layer thickness of 0.2 to 1.5 μm. The surface-coated cubic boron nitride-based ultrahigh-pressure sintered material-made cutting tool according to claim 1 formed.
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| KR102117429B1 (en) * | 2017-01-05 | 2020-06-01 | 두산중공업 주식회사 | Component for turbine having excellent erosion resistance and fatigue resistance |
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