JP2015164752A - Diamond-coated cemented carbide cutting tool - Google Patents
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本発明は、刃先に高負荷が作用するＣＦＲＰなどの難削材の高速高送り切削加工において、クラックの伝播を抑制することによって、すぐれた耐チッピング性、耐欠損性、耐剥離性を発揮するダイヤモンド被覆炭化タングステン基超硬合金製切削工具に関する。 The present invention exhibits excellent chipping resistance, chipping resistance, and peeling resistance by suppressing crack propagation in high-speed, high-feed cutting of difficult-to-cut materials such as CFRP in which a high load acts on the cutting edge. The present invention relates to a diamond-coated tungsten carbide-based cemented carbide cutting tool.
従来、炭化タングステン（ＷＣ）基超硬合金（以下、「超硬合金」という）からなる工具基体に、ダイヤモンド膜を被覆したダイヤモンド被覆超硬合金製切削工具（以下、「ダイヤモンド被覆工具」という）が知られているが、従来のダイヤモンド被覆工具においては、工具基体とダイヤモンド膜の密着性が十分でないため、これを改善するためにダイヤモンド膜を成膜する前に超硬合金製工具基体表面よりダイヤモンドの形成を阻害するコバルト（Ｃｏ）を除去し、工具基体上にダイヤモンド膜を成膜するなどの種々の提案がなされている。 Conventionally, a diamond-coated cemented carbide cutting tool (hereinafter referred to as a “diamond-coated tool”) in which a diamond film is coated on a tool base made of a tungsten carbide (WC) -based cemented carbide (hereinafter referred to as a “carbide”). However, in conventional diamond-coated tools, the adhesion between the tool base and the diamond film is not sufficient, so in order to improve this, the surface of the cemented carbide tool base before the diamond film is formed is improved. Various proposals have been made such as removing cobalt (Co), which hinders diamond formation, and forming a diamond film on a tool substrate.
例えば、特許文献１には、ダイヤモンド被覆工具において、超硬合金基体を段階的にエッチング処理することで基体表面のＣｏを除去し、超硬合金基体上にＷＣ粒子程度の凹凸を形成させ、ダイヤモンド膜を被覆することによって、ダイヤモンド膜と超硬合金製工具基体との密着性が改善されることが開示されている。 For example, in Patent Document 1, in a diamond-coated tool, a cemented carbide substrate is etched stepwise to remove Co on the substrate surface, and irregularities of about WC particles are formed on the cemented carbide substrate. It is disclosed that the adhesion between the diamond film and the cemented carbide tool substrate is improved by coating the film.
また、特許文献２には、ダイヤモンド被覆工具において、電解エッチング処理により凹凸が形成された超硬合金基体上にＷ等の中間層を被覆し、中間層上にダイヤモンド膜を被覆することによって、ダイヤモンド膜と工具基体との密着性改善を図ることが開示されている。 Patent Document 2 discloses a diamond-coated tool in which an intermediate layer such as W is coated on a cemented carbide substrate on which irregularities are formed by electrolytic etching, and a diamond film is coated on the intermediate layer. It is disclosed to improve the adhesion between the film and the tool substrate.
さらに、例えば、特許文献３には、超硬合金製工具基体をダイヤモンドで被覆するにあたり、超硬合金工具基体表面に元素周期律表ＩＶａ族、Ｖａ族、ＶＩａ族の金属炭化物、炭化ケイ素またはアルミナ等のセラミック粒子を埋め込み、電解エッチング処理を施すことにより基体表面に凹凸を形成することにより、工具基体とダイヤモンド膜の密着性を改善することが開示されている。 Further, for example, in Patent Document 3, when a cemented carbide tool base is coated with diamond, the element carbide periodic table IVa group, Va group, VIa group metal carbide, silicon carbide or alumina is provided on the surface of the cemented carbide tool base. It is disclosed that the adhesion between the tool substrate and the diamond film is improved by embedding ceramic particles such as the above and forming irregularities on the surface of the substrate by performing an electrolytic etching process.
近年の切削加工の技術分野における省力化および省エネ化、さらに低コスト化に対する要求は強く、これに伴い、切削加工は益々高速化の傾向にあるが、従来ダイヤモンド被覆工具を、例えば、ＣＦＲＰなどの難削材を高い加工精度で高速高送り切削に供した場合には、クラックの発生・伝播により、チッピング、欠損、剥離等の異常損傷が発生し易く、その結果、比較的短時間で使用寿命に至ることが多かった。 In recent years, there has been a strong demand for labor saving, energy saving, and cost reduction in the technical field of cutting, and along with this, cutting tends to increase more and more, but conventional diamond-coated tools such as CFRP, etc. When difficult-to-cut materials are subjected to high-speed, high-feed cutting with high machining accuracy, cracks are likely to cause abnormal damage such as chipping, chipping, and peeling due to the occurrence and propagation of cracks. In many cases.
例えば、特許文献１に開示されているような工具基体表面近傍の結合相量、すなわちＣｏ量を少なくすることによってダイヤモンド膜と工具基体との密着性を向上させる処理を行った場合であっても、ＣＦＲＰなどの高速重切削加工のように、刃先に短時間に繰り返し衝撃が作用する切削条件では、ダイヤモンド膜と超硬合金との界面のＣｏ量が減少した領域に発生したクラックが伝播することによって、チッピング、欠損、剥離等の異常損傷を発生させ、早期に切削工具としての寿命に至るという問題があった。 For example, even when a treatment for improving the adhesion between the diamond film and the tool base by reducing the amount of the binder phase near the tool base surface, that is, the amount of Co as disclosed in Patent Document 1, is performed. Under high cutting conditions such as high-speed heavy cutting such as CFRP, the cracks generated in the area where the amount of Co at the interface between the diamond film and the cemented carbide decreases is propagated under cutting conditions in which impact is repeatedly applied to the cutting edge in a short time. Therefore, there is a problem that abnormal damage such as chipping, chipping and peeling occurs, and the life as a cutting tool is reached at an early stage.
また、特許文献２に示すような前処理を行う場合、電解エッチングによりＷＣとＣｏが同時に溶出してしまうため、凸部の強度維持が困難であり、Ｗ等の中間層と超硬合金基体間の密着性にも問題があった。
また、特許文献３ではＳｉＣ粒子を超硬合金基体に埋め込み、ＳｉＣ粒子がエッチングを阻害するマスキングとして機能し、凸形状を超硬合金基体上に形成させているが、ＷＣ粒子間に隙間なくＳｉＣ粒子を埋め込むことは困難であり、硬い超硬合金基体に硬質セラミックスであるＳｉＣ粒子を埋め込むことは実用的であるとはいえない。
In addition, when pretreatment as shown in Patent Document 2 is performed, WC and Co are eluted simultaneously by electrolytic etching, so that it is difficult to maintain the strength of the convex portion, and between the intermediate layer such as W and the cemented carbide substrate. There was also a problem with the adhesion.
Further, in Patent Document 3, SiC particles are embedded in a cemented carbide substrate, and the SiC particles function as masking that inhibits etching, and a convex shape is formed on the cemented carbide substrate, but there is no gap between WC particles. It is difficult to embed particles, and it is not practical to bury SiC particles, which are hard ceramics, in a hard cemented carbide substrate.
そこで、本発明は、刃先に高負荷が作用するＣＦＲＰなどの難削材の高速高送り切削加工において、ダイヤモンド膜と工具基体との界面に発生したクラックの伝播を抑制することによって、チッピング、欠損、剥離等の耐異常損傷性を向上させ、すぐれた耐摩耗性を長期の使用に亘って発揮することができるダイヤモンド被覆工具を提供することを目的とする。 Therefore, the present invention provides chipping and chipping by suppressing the propagation of cracks generated at the interface between the diamond film and the tool base in high-speed high-feed cutting of difficult-to-cut materials such as CFRP in which a high load acts on the cutting edge. An object of the present invention is to provide a diamond-coated tool which can improve abnormal damage resistance such as peeling and can exhibit excellent wear resistance over a long period of use.
前述のようなダイヤモンド被覆工具の課題について本発明者らが鋭意、研究と実験を繰り返した結果、従来のダイヤモンド被覆工具においては、前述のようにダイヤモンド膜と工具基体との密着性を上げるために工具基体の最表面に存在する金属結合相中のＣｏを除去する処理を行っているが、その結果、刃先における靭性の低下を招き、刃先強度低下が生じている。 As a result of repeated research and experiments by the present inventors on the problems of the diamond-coated tool as described above, in the conventional diamond-coated tool, in order to increase the adhesion between the diamond film and the tool base as described above. A process of removing Co in the metal binder phase present on the outermost surface of the tool base is performed. As a result, the toughness of the cutting edge is reduced, and the strength of the cutting edge is reduced.
そこで、本発明者らは、例えば、ＣＦＲＰなどの難削材の高速高送り加工のように、切れ刃に高負荷が作用する切削条件に供した場合でも、すぐれた耐異常損傷性、耐摩耗性を発揮するダイヤモンド被覆工具を提供すべく、工具基体表面近傍に存在する金属結合相中のＣｏに焦点を当て鋭意研究を重ねたところ、次のような知見を得た。 Therefore, the present inventors have excellent abnormal damage resistance and wear resistance even when subjected to cutting conditions in which a high load acts on the cutting edge, such as high-speed high-feed machining of difficult-to-cut materials such as CFRP. In order to provide a diamond-coated tool that exhibits high performance, the inventors have conducted extensive research focusing on Co in the metal binder phase existing in the vicinity of the tool substrate surface, and obtained the following knowledge.
すなわち、
（１）超硬合金からなる工具基体が、その構成成分としてＴａＣ、ＮｂＣを含有する場合、焼結条件によって、ＴａＣ、ＮｂＣのＷＣ粒子間での粒成長が促進され、ＷＣ粒子間にＴａＣ、ＮｂＣが隙間なく充填されたＴａＣ、ＮｂＣ濃化領域が形成される。
（２）そのため、ＴａＣ、ＮｂＣが存在する箇所のＷＣ粒子間のＣｏ結合相は焼結時にＷＣ粒子間の外側に押し出される。
（３）前記の基体に酸溶液による化学的なエッチング（希硫酸＋過酸化水素水）を行うとＴａＣ、ＮｂＣが存在している箇所、例えば、前記ＴａＣ、ＮｂＣ濃化領域は残存するＣｏが少ないため、Ｃｏエッチングが進行しない。このためＴａＣ、ＮｂＣ濃化領域は酸に対してマスキングの効果を持ち、ＴａＣ、ＮｂＣ濃化領域より工具基体側はＣｏエッチングが進行せず、結合相を残存させることができる。一方、ＴａＣ、ＮｂＣ濃化領域の周囲の領域は酸エッチングによりＣｏが除去され、Ｃｏ貧化領域が形成される。
（４）上記ＴａＣ、ＮｂＣ濃化領域及びＣｏ貧化領域がその表面近傍に形成された超硬合金からなる工具基体の上に、ダイヤモンド膜を形成すると、このダイヤモンド被覆工具は、切削加工時にＣｏ貧化領域にクラックが発生したとしても、クラックの伝播が、前記ＴａＣ、ＮｂＣ濃化領域より基体側の金属結合相が残存する領域でその進展を抑制され、その結果、チッピング、欠損、剥離等の発生が低減され、耐異常損傷性が向上する。
That is,
(1) When the tool base made of cemented carbide contains TaC and NbC as its constituent components, grain growth between WC particles of TaC and NbC is promoted by sintering conditions, and TaC, TaC and NbC enriched regions filled with NbC are formed without any gaps.
(2) Therefore, the Co binder phase between the WC particles where TaC and NbC are present is pushed out to the outside between the WC particles during sintering.
(3) When chemical etching (dilute sulfuric acid + hydrogen peroxide solution) with an acid solution is performed on the substrate, the locations where TaC and NbC are present, for example, the TaC and NbC concentrated regions are made of the remaining Co. Since there are few, Co etching does not advance. For this reason, the TaC and NbC concentrated regions have a masking effect on the acid, and the Co etching does not proceed on the tool base side from the TaC and NbC concentrated regions, so that the binder phase can remain. On the other hand, in the region around the TaC and NbC enriched regions, Co is removed by acid etching to form a Co-poor region.
(4) When a diamond film is formed on a tool substrate made of a cemented carbide in which the TaC, NbC enriched region and the Co-poor region are formed in the vicinity of the surface, the diamond-coated tool is coated with Co during cutting. Even if cracks occur in the poor region, the propagation of the cracks is suppressed in the region where the metal bonding phase on the substrate side remains from the TaC and NbC concentration region, and as a result, chipping, chipping, peeling, etc. Occurrence is reduced, and abnormal damage resistance is improved.
本発明は、前記知見に基づいてなされたものであって、
「Ｃｏの平均含有量が３〜１５質量％、ＴａＣ、ＮｂＣの内の１種または２種の平均合計含有量が０．１〜３．０質量％、残部がＷＣからなる平均組成を有する炭化タングステン基超硬合金からなる工具基体表面に、平均膜厚３〜３０μｍのダイヤモンド膜が被覆形成されたダイヤモンド被覆超硬合金製切削工具において、
（ａ）前記工具基体表面から６μｍまでの深さ領域に、ＷＣ粒子で囲まれたＴａＣ、ＮｂＣ濃化領域が形成され、該ＴａＣ、ＮｂＣ濃化領域の内部は、Ｔａ、Ｎｂの内の１種または２種の平均合計含有量が全金属組成に対し５０質量％以上、及び平均含有量が１．０質量％以下のＣｏで構成され、
（ｂ）前記ＴａＣ、ＮｂＣ濃化領域の、深さ方向の平均長さは２〜６μｍであり、前記工具基体と平行な方向の平均幅は２〜６μｍであり、
（ｃ）前記ＴａＣ、ＮｂＣ濃化領域の、工具基体の縦断面について測定した前記ＴａＣ、ＮｂＣ濃化領域の単位面積当たりの生成密度は３０００〜１５０００個／ｍｍ２であり、
（ｄ）前記ＴａＣ、ＮｂＣ濃化領域に隣接し、工具基体表面からの最大深さが２〜６μｍの範囲には、エッチングによりＣｏが除去され、Ｃｏ量が１．０質量％以下であるＣｏ貧化領域が形成されていることを特徴とするダイヤモンド被覆超硬合金製切削工具。」
を特徴とするものである。
The present invention has been made based on the above findings,
“The average content of Co is 3 to 15% by mass, the average total content of one or two of TaC and NbC is 0.1 to 3.0% by mass, and the balance is an average composition consisting of WC. In a diamond coated cemented carbide cutting tool in which a diamond film with an average film thickness of 3 to 30 μm is coated on the surface of a tool base made of a tungsten-based cemented carbide,
(A) A TaC and NbC concentrated region surrounded by WC particles is formed in a depth region from the tool base surface to 6 μm, and the inside of the TaC and NbC concentrated region is one of Ta and Nb. The average total content of seeds or two types is composed of 50% by mass or more with respect to the total metal composition, and the average content is 1.0% by mass or less of Co,
(B) The average length in the depth direction of the TaC and NbC concentration region is 2 to 6 μm, the average width in the direction parallel to the tool base is 2 to 6 μm,
(C) The generation density per unit area of the TaC, NbC concentrated region measured from the longitudinal section of the tool base of the TaC, NbC concentrated region is 3000-15000 pieces / mm 2 ,
(D) Co having a maximum depth from the tool substrate surface of 2 to 6 μm adjacent to the TaC and NbC concentration region is removed by etching, and the Co content is 1.0 mass% or less. A diamond-coated cemented carbide cutting tool characterized in that an poor region is formed. "
It is characterized by.
以下、本発明について、図面と共に詳細に説明する。 Hereinafter, the present invention will be described in detail with reference to the drawings.
工具基体を構成する超硬合金中のＣｏの平均含有量：
工具基体を構成する超硬合金のＣｏの平均含有量が３質量％未満の場合、工具基体の靭性が低くなり切削時に欠損が生じやすくなるため好ましくない。一方、１５質量％を超えると、エッチング処理後、Ｃｏ貧化領域において空隙が占める体積割合が多くなり、Ｃｏが除去された領域が脆弱になるためダイヤモンド膜と工具表面との界面強度が低下し好ましくない。
したがって、工具基体を構成する超硬合金中のＣｏの平均含有量は、３〜１５質量％と定めた。
Average content of Co in the cemented carbide constituting the tool base:
When the average Co content of the cemented carbide constituting the tool base is less than 3% by mass, the toughness of the tool base becomes low and defects are likely to occur during cutting, which is not preferable. On the other hand, if it exceeds 15% by mass, the volume ratio occupied by the voids in the Co-poor region after etching is increased, and the region from which Co is removed becomes brittle, so the interface strength between the diamond film and the tool surface decreases. It is not preferable.
Therefore, the average content of Co in the cemented carbide constituting the tool base is determined to be 3 to 15% by mass.
工具基体を構成する超硬合金中のＴａＣ、ＮｂＣの内の１種または２種の合計含有量：
工具基体を構成する超硬合金中のＴａＣ、ＮｂＣの内の１種または２種の平均合計含有量が、０．１質量％未満の場合、図１に示すＴａＣ、ＮｂＣ濃化領域（以下、単に「濃化領域」という場合もある）、即ち、ＷＣ粒子で囲まれた領域であって、該領域の内部は、ＴａＣ、ＮｂＣの内の１種または２種、及び１．０質量％以下のＣｏで構成されている濃化領域の形成が少なくなるため、クラックの伝播・進展抑制効果を期待することができず、一方、ＴａＣ、ＮｂＣの内の１種または２種の合計平均含有量が、３．０質量％を超える場合には、工具基体の靭性が低下し、欠損を生じる恐れがある。
したがって、工具基体を構成する超硬合金中のＴａＣ、ＮｂＣの内の１種または２種の平均合計含有量は、０．１〜３．０質量％と定めた。
Total content of one or two of TaC and NbC in the cemented carbide constituting the tool base:
When the average total content of one or two of TaC and NbC in the cemented carbide constituting the tool base is less than 0.1% by mass, the TaC and NbC concentration region (hereinafter referred to as It may be simply referred to as a “concentrated region”), that is, a region surrounded by WC particles, and the inside of the region is one or two of TaC and NbC, and 1.0% by mass or less. Since the formation of the concentrated region composed of Co is reduced, it is not possible to expect the effect of suppressing the propagation / development of cracks, while the total average content of one or two of TaC and NbC However, when it exceeds 3.0 mass%, the toughness of a tool base | substrate may fall and it may produce a defect | deletion.
Therefore, the average total content of one or two of TaC and NbC in the cemented carbide constituting the tool base is determined to be 0.1 to 3.0% by mass.
工具基体表面から深さ６μｍまでの工具基体内部側の領域（以下、「工具基体表面近傍」という）に形成されるＴａＣ、ＮｂＣ濃化領域：
工具基体表面近傍に形成される図１に示す濃化領域、即ち、ＷＣ粒子で囲まれた領域であって、該領域の内部は、ＴａＣ、ＮｂＣの内の１種または２種、及び１．０質量％以下のＣｏで構成されているＴａＣ、ＮｂＣ濃化領域、の工具基体表面からの平均深さが２μｍ未満の場合、あるいは、平均深さが６μｍを超えるような場合には、該領域を囲むＷＣ粒子間に隙間を生じ、１．０質量％を超えるＣｏが該領域内に残存するため、エッチングによってＣｏの除去が進行し、クラックの伝播・進展を抑制する機能を有するＴａＣ、ＮｂＣ濃化領域を形成することができない。
したがって、工具基体表面近傍に形成されるＴａＣ、ＮｂＣ濃化領域は、その深さ方向の平均長さを２〜６μｍと定めた。
該ＴａＣ、ＮｂＣ濃化領域の内部のＴａ、Ｎｂの内の１種または２種の平均合計含有量が全金属組成に対し５０質量％未満の場合、該ＴａＣ、ＮｂＣ濃化領域に残存するＣｏが多くなるため、酸エッチングにおけるマスキングの効果が得られにくい。
なお、濃化領域の内部にはＣｏが残存しないことが望ましいが、Ｃｏ残存量が１．０質量％以下であるような場合には、エッチングの進行が実質的に抑えられることから、濃化領域の内部には、１．０質量％以下の範囲において、Ｃｏの残存も許容される。
なお、工具基体表面近傍に濃化領域を形成する方法については、後記する。
TaC and NbC enriched regions formed in a region inside the tool substrate from the tool substrate surface to a depth of 6 μm (hereinafter referred to as “the vicinity of the tool substrate surface”):
1 is formed in the vicinity of the tool substrate surface, that is, an area surrounded by WC particles, and the inside of the area is one or two of TaC and NbC, and When the average depth of TaC and NbC enriched regions composed of 0% by mass or less of Co from the tool base surface is less than 2 μm, or when the average depth exceeds 6 μm, this region TaC, NbC having a function of suppressing the propagation and progress of cracks because Co is removed by etching and Co is removed in the region because a gap is generated between WC particles surrounding the WC particles and Co exceeding 1.0% by mass remains in the region. A concentrated region cannot be formed.
Therefore, the TaC and NbC concentrated region formed in the vicinity of the tool base surface has an average length in the depth direction of 2 to 6 μm.
When the average total content of one or two of Ta and Nb in the TaC and NbC concentration region is less than 50% by mass with respect to the total metal composition, the Co remaining in the TaC and NbC concentration region Therefore, it is difficult to obtain a masking effect in acid etching.
Although it is desirable that no Co remains in the concentration region, if the remaining amount of Co is 1.0% by mass or less, the progress of etching is substantially suppressed. Co remains in the region within a range of 1.0 mass% or less.
A method for forming the concentrated region in the vicinity of the tool base surface will be described later.
工具基体表面近傍に形成される図１に示す濃化領域の平均幅が、工具基体と平行な面（断面）で測定して２μｍ未満の場合、あるいは、平均幅が６μｍを超えるような場合には、該領域を囲むＷＣ粒子間に隙間を生じ、１．０質量％を超えるＣｏが該領域内に残存するため、エッチングが進行し、クラックの伝播・進展を抑制する機能を有する濃化領域を形成することができない。
したがって、工具基体と平行な面（断面）で測定した工具基体表面近傍に形成される濃化領域の平均幅は、２〜６μｍと定めた。
When the average width of the concentrated region shown in FIG. 1 formed in the vicinity of the tool base surface is less than 2 μm as measured on a plane (cross section) parallel to the tool base, or when the average width exceeds 6 μm. Is a concentrated region that has a function of suppressing the propagation and propagation of cracks because a gap is generated between WC particles surrounding the region, and Co exceeding 1.0 mass% remains in the region. Can not form.
Therefore, the average width of the concentrated region formed in the vicinity of the tool base surface measured on a plane (cross section) parallel to the tool base was determined to be 2 to 6 μm.
工具基体表面近傍に形成される図１に示す濃化領域の生成密度が、工具基体の表面について測定した場合に３０００個／ｍｍ２未満である場合は、クラックの伝播・進展を抑制する作用を有する濃化領域の数が少ないため、クラックの伝播・進展を抑制する効果が十分でなく、一方、工具基体の表面について測定した濃化領域の生成密度が１５０００個／ｍｍ２を超える場合は、工具基体表面近傍に過度にＴａＣ、ＮｂＣが集中するため、工具基体表面の靭性が低下し、欠損を生じやすくなる。
したがって、工具基体の表面で測定した工具基体表面近傍に形成される濃化領域の生成密度は、３０００〜１５０００個／ｍｍ２と定めた。
If the generation density of the concentrated region shown in FIG. 1 formed in the vicinity of the tool base surface is less than 3000 / mm 2 when measured on the surface of the tool base, the effect of suppressing the propagation and propagation of cracks is exerted. Since the number of the concentrated regions is small, the effect of suppressing the propagation / development of cracks is not sufficient. On the other hand, when the density of the concentrated regions measured on the surface of the tool substrate exceeds 15000 / mm 2 , Since TaC and NbC are excessively concentrated in the vicinity of the tool base surface, the toughness of the tool base surface is lowered and defects are likely to occur.
Therefore, the production density of the concentrated region formed in the vicinity of the tool base surface measured on the surface of the tool base was determined to be 3000 to 15000 pieces / mm 2 .
ＴａＣ、ＮｂＣ濃化領域に隣接し、かつ、工具基体表面から最大深さが２〜６μｍの範囲に形成されるＣｏ貧化領域：
ＴａＣ、ＮｂＣ濃化領域に隣接し、かつ、工具基体表面から最大深さが２〜６μｍの範囲には、図１に示すように、平均組成よりＣｏ含有量が少ないＣｏ貧化領域（以下、単に「貧化領域」という場合もある）を形成する。該貧化領域は、例えば、工具基体を酸エッチングし、基体表面からＣｏを除去することによって形成する。
Ｃｏ貧化領域は、工具基体表面から最大深さが２μｍ未満である場合には、ダイヤモンド膜と工具基体との密着性が十分でなく、剥離を生じやすく、一方、その最大深さが６μｍを超える場合には、該貧化領域にクラックが生じやすくなり耐チッピング性、耐欠損性が低下する。
したがって、Ｃｏ貧化領域は、工具基体表面から最大深さが２〜６μｍの範囲に形成する。
なお、貧化領域は、エッチングによってＣｏが除去された領域であるが、Ｃｏの残存量が１．０質量％以下であれば、ダイヤモンド膜との密着性に影響はないことから、Ｃｏ貧化領域におけるＣｏ残存量は１．０質量％以下とする。
Co poor region formed adjacent to TaC and NbC enriched region and having a maximum depth of 2 to 6 μm from the tool substrate surface:
As shown in FIG. 1, a Co-poorized region (hereinafter referred to as “Co-poorized region”) having a lower Co content than the average composition is adjacent to the TaC and NbC-concentrated region and has a maximum depth of 2 to 6 μm from the tool base surface. Simply called “poor region”). The poor region is formed, for example, by acid-etching the tool substrate and removing Co from the substrate surface.
When the maximum depth of the Co-poor region is less than 2 μm from the surface of the tool base, the adhesion between the diamond film and the tool base is not sufficient, and peeling tends to occur, while the maximum depth is 6 μm. If exceeding, cracks are likely to occur in the poor region, and chipping resistance and chipping resistance are lowered.
Therefore, the Co-poor region is formed in a range where the maximum depth is 2 to 6 μm from the tool base surface.
The poor region is a region where Co has been removed by etching. However, if the remaining amount of Co is 1.0% by mass or less, there is no influence on the adhesion to the diamond film, and therefore Co poor. The remaining amount of Co in the region is 1.0% by mass or less.
ここで、工具基体表面近傍におけるＴａＣ、ＮｂＣ濃化領域の深さ方向の平均長さ、工具基体と平行な面で測定した平均幅および工具基体の縦断面で測定したＴａＣ、ＮｂＣ濃化領域の生成密度、また、Ｃｏ貧化領域が形成された工具基体表面から最大深さは、次のような方法で求めた。
走査型電子顕微鏡により工具基体表面近傍の断面観察を行い、ダイヤモンド膜と工具基体との界面より工具基体の内部側に深さ１０μｍ、基体表面と平行方向に１００μｍの観察領域で得られた画像内に観察された複数のＴａＣ、ＮｂＣ濃化領域およびＣｏ貧化領域について、それぞれの工具基体表面からの深さと幅を測定する。そして、測定した複数のＴａＣ、ＮｂＣ濃化領域およびＣｏ貧化領域の深さを平均し、これをＴａＣ、ＮｂＣ濃化領域の深さ方向の平均長さとし、また、Ｃｏ貧化領域の最大深さとした。また、測定した複数のＴａＣ、ＮｂＣ濃化領域において工具基体の表面と平行方向の幅を平均し、これをＴａＣ、ＮｂＣ濃化領域の平均幅とした。また、ＴａＣ、ＮｂＣ濃化領域の生成密度については、脱膜処理によってダイヤモンド膜が除去された試料の表面の任意の１００μｍ四方の３視野をエネルギー分散型Ｘ線分光法よって面分析を行い、カウントされた個数の平均値を、単位面積当たり（個／ｍｍ２）に換算することによって求めた。
また、ＴａＣ、ＮｂＣ濃化領域及びＣｏ貧化領域におけるＴａＣ、ＮｂＣ、Ｃｏ含有量については、試料の断面をオージェ電子分光法（Ａｕｇｅｒ Ｅｌｅｃｔｒｏｎ Ｓｐｅｃｔｒｏｓｃｏｐｙ：ＡＥＳ）により測定することにより求めた。
Here, the average length in the depth direction of the TaC and NbC concentrated regions in the vicinity of the tool substrate surface, the average width measured in a plane parallel to the tool substrate, and the TaC and NbC concentrated regions measured in the longitudinal section of the tool substrate. The generation density and the maximum depth from the surface of the tool base on which the Co-poor region was formed were determined by the following method.
The cross section of the surface of the tool base is observed with a scanning electron microscope, and the image is obtained in an observation region having a depth of 10 μm on the inner side of the tool base from the interface between the diamond film and the tool base and 100 μm in the direction parallel to the base surface. The depth and width from the surface of each tool substrate are measured for the plurality of TaC, NbC enriched regions and Co-poor regions observed in (1). Then, the measured depths of the TaC and NbC enriched regions and the Co enriched region are averaged, and this is defined as the average length in the depth direction of the TaC and NbC enriched regions, and the maximum depth of the Co enriched region. Say it. Further, the widths in the direction parallel to the surface of the tool base were averaged in the plurality of measured TaC and NbC concentrated regions, and this was defined as the average width of the TaC and NbC concentrated regions. The generation density of the TaC and NbC enriched regions is determined by performing surface analysis by energy dispersive X-ray spectroscopy on any three 100 μm square fields on the surface of the sample from which the diamond film has been removed by film removal. The average value of the number obtained was calculated by converting per unit area (pieces / mm 2 ).
Further, the TaC, NbC, and Co content in the TaC, NbC enriched region and Co-poor region were determined by measuring the cross section of the sample by Auger Electron Spectroscopy (AES).
ダイヤモンド膜の平均膜厚：
本発明の工具基体表面に被覆するダイヤモンド膜の平均膜厚が３μｍ未満では、長期の使用に亘って十分な耐摩耗性を発揮することができない。一方、ダイヤモンド膜厚が３０μｍを超えると、チッピング、欠損、剥離が発生しやすくなり、かつ加工精度も低下する。したがって、ダイヤモンド膜の平均膜厚は、３〜３０μｍと定めた。
Average film thickness of diamond film:
When the average film thickness of the diamond film coated on the surface of the tool substrate of the present invention is less than 3 μm, sufficient wear resistance cannot be exhibited over a long period of use. On the other hand, if the diamond film thickness exceeds 30 μm, chipping, chipping, and peeling are likely to occur, and the processing accuracy also decreases. Therefore, the average film thickness of the diamond film was determined to be 3 to 30 μm.
本発明のダイヤモンド被覆工具は、次のような製法で製造することができる。
（１）まず、所定の含有割合のＣｏ、ＴａＣ、ＮｂＣを含有するＷＣ基超硬合金を焼結する際、ＴａＣ、ＮｂＣの粒成長を施すため、ＴａＣ、ＮｂＣの粒径は１μｍ程度が好ましく、より好ましくは１μｍ以下の微粒が好ましい。そして、２段階の焼結条件で焼結することにより、ＴａＣ、ＮｂＣが粒成長し、ＷＣ粒子間にＴａＣ、ＮｂＣが隙間なく充填されるＴａＣ、ＮｂＣ濃化領域を形成する。
（２）次いで、前記焼結体を研磨加工して、工具基体を形成する。
（３）前処理として、前記工具基体を酸でエッチングした後、希硫酸（１％）と過酸化水素（５％）とからなる酸混合溶液１Ｌに８〜１５秒間、室温（２３℃）で浸漬し、工具基体表面近傍のＣｏをエッチングで除去し、工具基体表面近傍にＣｏ貧化領域を形成する。
（４）次いで、熱フィラメントＣＶＤプロセスにより、平均膜厚３〜３０μｍのダイヤモンド膜を基体に被覆する。
上記の工程（１）〜（４）によって、本発明のダイヤモンド被覆工具を作製することができる。
The diamond-coated tool of the present invention can be manufactured by the following manufacturing method.
(1) First, when sintering a WC-based cemented carbide containing Co, TaC, and NbC in a predetermined content ratio, TaC and NbC grain growth is preferably performed, so that the grain size of TaC and NbC is preferably about 1 μm. More preferably, fine particles of 1 μm or less are preferred. By sintering under two-stage sintering conditions, TaC and NbC are grain-grown, and a TaC and NbC enriched region in which TaC and NbC are filled with no gap between WC particles is formed.
(2) Next, the sintered body is polished to form a tool base.
(3) As a pretreatment, after etching the tool base with an acid, it is added to 1 L of an acid mixed solution composed of dilute sulfuric acid (1%) and hydrogen peroxide (5%) at room temperature (23 ° C.) for 8 to 15 seconds. Immersion is performed, and Co in the vicinity of the tool base surface is removed by etching to form a Co poor region in the vicinity of the tool base surface.
(4) Next, a diamond film having an average film thickness of 3 to 30 μm is coated on the substrate by a hot filament CVD process.
The diamond-coated tool of the present invention can be produced by the above steps (1) to (4).
図１には、上記で作製した本発明のダイヤモンド被覆工具のダイヤモンド膜と基体の界面の断面の模式図を示す。
また、図２には、上記で作製した本発明ダイヤモンド被覆工具の断面を、走査型電子顕微鏡で観察した反射電子像を示す。
図２には、工具基体表面近傍に、ＷＣ粒子で囲まれた領域であって、かつ、該領域の内部は、ＴａＣ、ＮｂＣの内の１種または２種、及び１．０質量％以下のＣｏで構成されている濃化領域（ＴａＣ、ＮｂＣ濃化領域）が示されており、ＴａＣ、ＮｂＣの内の１種または２種が存在する領域の末端を境界として、濃化領域の工具基体の表面と平行方向の直線距離の幅は約２μｍ、深さ方向の直線距離の長さは約３μｍであることが分かる。
図３には、走査型電子顕微鏡により観察した広視野の電子像を示しており、（ａ）は、二次電子像、（ｂ）は、反射電子像を示す。反射電子像において、結合相の濃淡が濃い領域にＴａＣ、ＮｂＣ濃化領域を確認した。
また、ＡＥＳによりＴａＣ、ＮｂＣ濃化領域の組成分析を行ったところ、ＴａＣ、ＮｂＣ濃化領域は、ＷＣ粒子で囲まれた領域であって、かつ、該領域の内部は、ＴａＣ、ＮｂＣの内の１種または２種、及び１．０質量％以下のＣｏで構成されていることを確認した。
また、Ｃｏ貧化領域については、同じくＡＥＳにより組成分析を行ったところ、ＷＣ粒子間に存在するＣｏ残存量は１．０質量％以下であって、ＴａＣ、ＮｂＣはＡＥＳによる検出限界以下であり、ＷＣ粒子間にはエッチングによってＣｏが除去された空孔が形成されていた。
FIG. 1 shows a schematic diagram of a cross section of the interface between the diamond film and the substrate of the diamond-coated tool of the present invention produced as described above.
FIG. 2 shows a backscattered electron image obtained by observing the cross section of the diamond-coated tool of the present invention produced above with a scanning electron microscope.
FIG. 2 shows a region surrounded by WC particles in the vicinity of the tool substrate surface, and the inside of the region is one or two of TaC and NbC, and 1.0% by mass or less. A thickened region composed of Co (TaC, NbC thickened region) is shown, and the tool base of the thickened region is bounded by the end of the region where one or two of TaC and NbC are present. It can be seen that the width of the linear distance in the direction parallel to the surface is about 2 μm, and the length of the linear distance in the depth direction is about 3 μm.
FIG. 3 shows a wide-field electron image observed with a scanning electron microscope, where (a) shows a secondary electron image and (b) shows a reflected electron image. In the backscattered electron image, TaC and NbC enriched regions were confirmed in regions where the binder phase was dark.
In addition, when the composition analysis of the TaC and NbC concentrated region was performed by AES, the TaC and NbC concentrated region was a region surrounded by WC particles, and the inside of the region was the inside of TaC and NbC. It was confirmed that it was composed of one or two of the above and 1.0% by mass or less of Co.
In addition, regarding the Co-poor region, the same composition analysis was performed by AES. As a result, the residual amount of Co existing between WC particles was 1.0% by mass or less, and TaC and NbC were below the detection limit by AES. In addition, pores from which Co was removed by etching were formed between the WC particles.
本発明のダイヤモンド被覆超硬合金製切削工具は、Ｃｏが３〜１５質量％、ＴａＣ、ＮｂＣの内の１種または２種の合計量が０．１〜３．０質量％、残部がＷＣで構成される炭化タングステン基超硬合金からなる工具基体にダイヤモンド膜を被覆形成したものであって、工具基体表面から６μｍまでの深さ領域に、ＷＣ粒子で囲まれ、かつ、その内部は、ＴａＣ、ＮｂＣの内の１種または２種、及び１．０質量％以下のＣｏで構成されたＴａＣ、ＮｂＣ濃化領域を形成し、ＴａＣ、ＮｂＣ濃化領域の深さ方向の平均長さ、平均幅および生成密度を適正数値範囲に定めるとともに、ＴａＣ、ＮｂＣ濃化領域に隣接してＣｏ貧化領域を形成したことによって、ＣＦＲＰなどの難削材の高速高送り切削加工においても、ダイヤモンド膜の密着性を低下させることなく、クラックの伝播・進展を抑制して、すぐれた耐チッピング性、耐欠損性、耐剥離性を発揮し、異常損傷の発生を招くことなく長期の使用に亘ってすぐれた耐摩耗性を発揮するものである。 In the diamond coated cemented carbide cutting tool of the present invention, Co is 3 to 15% by mass, the total amount of one or two of TaC and NbC is 0.1 to 3.0% by mass, and the balance is WC. A tool substrate made of a tungsten carbide-based cemented carbide alloy is coated with a diamond film, and is surrounded by WC particles in a depth region from the tool substrate surface to 6 μm, and the inside thereof is TaC. , One or two of NbC, and a TaC, NbC enriched region composed of 1.0% by mass or less of Co, and an average length in the depth direction of the TaC, NbC enriched region, average In addition to setting the width and generation density within appropriate numerical ranges and forming the Co-poor region adjacent to the TaC and NbC enriched regions, the diamond film can be used in high-speed, high-feed cutting of difficult-to-cut materials such as CFRP. Low adhesion Without cracking, it suppresses the propagation and propagation of cracks, exhibits excellent chipping resistance, chipping resistance, and peeling resistance, and has excellent wear resistance over long-term use without causing abnormal damage. To demonstrate.
つぎに、本発明のダイヤモンド被覆工具について、実施例に基づき具体的に説明する。
なお、ここでは、ダイヤモンド被覆工具の具体例としてダイヤモンド被覆超硬合金製ドリルについて述べるが、本発明はこれに限られるものではなく、ダイヤモンド被覆超硬合金製インサート、ダイヤモンド被覆超硬合金製エンドミル等、各種のダイヤモンド被覆工具に適用できることは言うまでもない。
Next, the diamond-coated tool of the present invention will be specifically described based on examples.
Here, although a diamond-coated cemented carbide drill is described as a specific example of the diamond-coated tool, the present invention is not limited to this, but a diamond-coated cemented carbide insert, a diamond-coated cemented carbide end mill, etc. Needless to say, the present invention can be applied to various diamond-coated tools.
（ａ）原料粉末として、いずれも０．５〜１．０μｍの範囲内の所定の平均粒径を有するＷＣ粉末、Ｃｏ粉末、ＴａＣ粉末、ＮｂＣ粉末を、表１に示される割合に配合し、さらにバインダーと溶剤を加えてアセトン中で２４時間ボールミル混合し、減圧乾燥した後、いずれも押し出しプレス成形し、直径が１０ｍｍの丸棒圧粉体とし、これらの丸棒圧粉体を、表３に示す２段階の１Ｐａの真空雰囲気中、１３８０〜１５００℃の温度で１〜２時間保持するという条件で焼結することにより焼結体を作製し、該焼結体を研磨加工することにより、ＴａＣ、ＮｂＣ濃化領域が形成されたＷＣ基超硬合金焼結体を製造した。
ついで、前記ＷＣ基超硬合金焼結体を、溝形成部の外径寸法がφ６ｍｍ、長さ８０ｍｍとなるように研削加工することにより、本発明のＷＣ基超硬合金製ドリル基体（以下、単に「本発明ドリル基体」という）を製造した。
(A) As a raw material powder, WC powder, Co powder, TaC powder, and NbC powder each having a predetermined average particle diameter in the range of 0.5 to 1.0 μm are blended in the ratio shown in Table 1, Further, a binder and a solvent were added, mixed in a ball mill in acetone for 24 hours, dried under reduced pressure, and then extruded and pressed to form a round bar green compact having a diameter of 10 mm. In a two-stage 1 Pa vacuum atmosphere shown in 1), a sintered body is produced by sintering at a temperature of 1380 to 1500 ° C. for 1 to 2 hours, and the sintered body is polished. A WC-based cemented carbide sintered body in which TaC and NbC enriched regions were formed was manufactured.
Next, the WC-based cemented carbide sintered body is ground so that the outer diameter dimension of the groove forming portion is 6 mm and the length is 80 mm. This was simply referred to as “the drill base of the present invention”.
（ｂ）ついで、前記本発明ドリル基体を、希硫酸（１．０％）と過酸化水素（５％）とからなる酸混合溶液１Ｌに６〜１５秒間、室温（２３℃）で浸漬し、ドリル基体表面近傍のＣｏをエッチングで除去し、本発明ドリル基体表面近傍にＣｏ貧化領域を形成した。 (B) Next, the drill base of the present invention is immersed in 1 L of an acid mixed solution composed of dilute sulfuric acid (1.0%) and hydrogen peroxide (5%) for 6 to 15 seconds at room temperature (23 ° C.). Co near the surface of the drill base was removed by etching to form a Co-poor region near the surface of the drill base of the present invention.
（ｃ）次いで、前記本発明ドリル基体を、０．１μｍ以下の一次粒子径を有するダイヤモンド粉末を配合したエタノール中で超音波処理による傷つけ処理を行い、ついで、熱フィラメントＣＶＤ装置に装入し、フィラメント温度を２２００℃、水素ガスとメタンガスを１００：１の流量比で流しながら、工具基体温度を９００℃に維持し、３〜３０μｍの膜厚のダイヤモンド膜を成膜することにより、表５に示す本発明のダイヤモンド被覆ＷＣ基超硬合金製ドリル（以下、単に、「本発明ドリル」という）１〜９を製造した。 (C) Next, the drill base of the present invention was subjected to a scratching process by ultrasonic treatment in ethanol mixed with diamond powder having a primary particle size of 0.1 μm or less, and then charged into a hot filament CVD apparatus. By maintaining a tool substrate temperature at 900 ° C. while flowing a filament temperature of 2200 ° C. and hydrogen gas and methane gas at a flow rate ratio of 100: 1, a diamond film having a thickness of 3 to 30 μm is formed. The following diamond-coated WC-based cemented carbide drills (hereinafter simply referred to as “the present invention drill”) 1 to 9 of the present invention were manufactured.
比較のため、表２に示される割合に配合された原料粉末を用いて、表４に示す条件で焼結することにより焼結体を作製し、該焼結体を研磨加工することによりＷＣ基超硬合金焼結体を製造し、ついで、このＷＣ基超硬合金焼結体を、溝形成部の外径寸法がφ６ｍｍ、長さ８０ｍｍとなるように研削加工することにより、比較例のＷＣ基超硬合金製ドリル基体（以下、単に「比較例ドリル基体」という）を製造した。 For comparison, a raw material powder blended in the ratio shown in Table 2 is used to sinter the sintered body under the conditions shown in Table 4, and the sintered body is polished to produce a WC group. A cemented carbide sintered body was manufactured, and then this WC-based cemented carbide sintered body was ground so that the outer diameter dimension of the groove forming portion was φ6 mm and the length was 80 mm. A base cemented carbide drill base (hereinafter simply referred to as “comparative example drill base”) was produced.
ついで、前記比較例ドリル基体を、希硫酸（１．０％）と過酸化水素（５％）とからなる酸混合溶液１Ｌに６〜１５秒間、室温（２３℃）で浸漬し、ドリル基体表面近傍のＣｏをエッチングで除去し、比較例ドリル基体表面近傍にＣｏ貧化領域を形成した。 Subsequently, the drill base of the comparative example was immersed in 1 L of an acid mixed solution composed of dilute sulfuric acid (1.0%) and hydrogen peroxide (5%) for 6 to 15 seconds at room temperature (23 ° C.), and the drill base surface Nearby Co was removed by etching to form a Co-poor region near the surface of the comparative drill base.
次いで、前記比較例ドリル基体を、０．１μｍ以下の一次粒子径を有するダイヤモンド粉末を配合したエタノール中で超音波処理による傷つけ処理を行い、ついで、熱フィラメントＣＶＤ装置に装入し、フィラメント温度を２２００℃、水素ガスとメタンガスを１００：１の流量比で流しながら、工具基体温度を９００℃に維持し、３〜３０μｍの膜厚のダイヤモンド膜を成膜することにより、表６に示す比較例のダイヤモンド被覆ＷＣ基超硬合金製ドリル（以下、単に、「比較例ドリル」という）１〜１２を製造した。 Subsequently, the comparative drill base was subjected to scratching treatment by ultrasonic treatment in ethanol mixed with diamond powder having a primary particle size of 0.1 μm or less, and then charged into a hot filament CVD apparatus to adjust the filament temperature. Comparative Example shown in Table 6 by forming a diamond film having a thickness of 3 to 30 μm while maintaining the tool substrate temperature at 900 ° C. while flowing hydrogen gas and methane gas at a flow rate ratio of 100: 1 at 2200 ° C. Diamond-coated WC-based cemented carbide drills (hereinafter simply referred to as “comparative example drills”) 1 to 12 were manufactured.
本発明ドリル１〜９、比較例ドリル１〜１２のダイヤモンド膜の膜厚を、走査型電子顕微鏡を用いて断面観察により、観察視野内の５点の膜厚を測定し、平均膜厚を算出した。
表５、６にこれらの値を示す。
The film thicknesses of the diamond films of the present invention drills 1 to 9 and comparative drills 1 to 12 were measured by measuring the film thickness at five points in the observation field by cross-sectional observation using a scanning electron microscope, and the average film thickness was calculated. did.
Tables 5 and 6 show these values.
また、本発明ドリル１〜９、比較例ドリル１〜１２について走査型電子顕微鏡による断面観察により、工具基体表面近傍に形成されたＴａＣ、ＮｂＣ濃化領域（即ち、ＷＣ粒子で囲まれた、その内部は、ＴａＣ、ＮｂＣの内の１種または２種、及び１．０質量％以下のＣｏで構成された領域）の、深さ方向の平均長さ、平均幅を測定した。
その結果、本発明ドリル１〜９において観察されたＴａＣ、ＮｂＣ濃化領域は、いずれも、深さ方向の平均長さは２〜６μｍ、平均幅は２〜６μｍであることが確認された。
また、本発明ドリル１〜９、比較例ドリル１〜１２についてＡｒガス雰囲気下で工具基体を高周波発生装置による誘導加熱処理により、２０秒間１２００℃に保持する脱膜処理を実施することにより、ダイヤモンド膜が除去された試料の表面をエネルギー分散型Ｘ線分光法にて面分析を実施し、工具基体表面近傍に形成されたＴａＣ、ＮｂＣ濃化領域の単位面積当たりの生成密度は３０００〜１５０００個／ｍｍ２であることが確認された。
また、本発明ドリル１〜９について、工具基体表面からの最大深さが２〜６μｍの範囲に形成されたＣｏ貧化領域の最大深さを測定した。
さらに、ＴａＣ、ＮｂＣ濃化領域及びＣｏ貧化領域について、ＡＥＳにより組成分析を行い、それぞれの領域における全金属成分に対するＴａ，Ｎｂ，Ｗ, Ｃｏの平均含有量を測定した。
表５、表６に、これらの測定結果を示す。
Further, by observing the present invention drills 1 to 9 and comparative drills 1 to 12 by cross-sectional observation using a scanning electron microscope, TaC and NbC concentrated regions formed in the vicinity of the tool base surface (that is, surrounded by WC particles, For the inside, the average length in the depth direction and the average width of one or two of TaC and NbC and a region composed of 1.0% by mass or less of Co were measured.
As a result, it was confirmed that the TaC and NbC enriched regions observed in the drills 1 to 9 of the present invention had an average length in the depth direction of 2 to 6 μm and an average width of 2 to 6 μm.
In addition, the drills of the present invention drills 1 to 9 and comparative example drills 1 to 12 were subjected to a film removal treatment in which the tool base was held at 1200 ° C. for 20 seconds by induction heat treatment using a high frequency generator in an Ar gas atmosphere. The surface of the sample from which the film was removed was subjected to surface analysis by energy dispersive X-ray spectroscopy, and the generation density per unit area of TaC and NbC concentrated regions formed in the vicinity of the tool base surface was 3000 to 15000. / Mm 2 was confirmed.
Moreover, about this invention drill 1-9, the maximum depth of the Co poor area | region formed in the range whose maximum depth from the tool base | substrate surface is 2-6 micrometers was measured.
Further, the TaC, NbC enriched region and the Co poor region were subjected to composition analysis by AES, and the average content of Ta, Nb, W, and Co with respect to all metal components in each region was measured.
Tables 5 and 6 show the measurement results.
つぎに、前記本発明ドリル１〜９および比較例ドリル１〜１２（いずれも、ドリル径はφ６ｍｍ）を用いて、以下の条件で、ＣＦＲＰの高速高送りドリル穴開け試験を行った。
被削材：厚さ１５ｍｍのＣＦＲＰ，
切削速度：２２０ｍ／ｍｉｎ（通常の切削速度は、１００ｍ／ｍｉｎ），
送り：０．３２ｍｍ／ｒｅｖ（通常の送りは、０．１ｍｍ／ｒｅｖ），
穴深さ：２０ｍｍ（貫通穴），
前記切削試験において、切削の異常音および切削時の荷重が異常を示した際に、試験を中断し、チッピング、欠損、剥離等の異常損傷の有無を確認した。チッピング、欠損、剥離等の異常損傷の発生が確認された場合、それまでの穴あけ加工数を加工寿命とした。
また、本発明ドリルの合格条件として、１００穴迄欠損せず、切れ刃の中央の逃げ面の摩耗形態が正常であることとした。
表７，８にこれらの評価結果を示す。
Next, a high-speed, high-feed drill drilling test of CFRP was performed under the following conditions using the drills 1 to 9 of the present invention and the drills of comparative examples 1 to 12 (both had a drill diameter of 6 mm).
Work material: CFRP with a thickness of 15 mm,
Cutting speed: 220 m / min (normal cutting speed is 100 m / min),
Feed: 0.32 mm / rev (normal feed is 0.1 mm / rev),
Hole depth: 20mm (through hole),
In the cutting test, when the abnormal sound of cutting and the load at the time of cutting showed an abnormality, the test was interrupted, and the presence or absence of abnormal damage such as chipping, chipping or peeling was confirmed. When the occurrence of abnormal damage such as chipping, chipping or peeling was confirmed, the number of drilling operations so far was defined as the processing life.
In addition, as a passing condition for the drill of the present invention, it was decided that the wear form of the flank at the center of the cutting edge was normal, with no defects up to 100 holes.
Tables 7 and 8 show the evaluation results.
表５〜８の結果からも明らかなように、本発明ドリル１〜９は、工具基体表面近傍に、所定の深さ方向平均長さ、平均幅、所定生成密度のＴａＣ、ＮｂＣ濃化領域（即ち、ＷＣ粒子で囲まれ、その内部は、ＴａＣ、ＮｂＣの内の１種または２種、及び１．０質量％以下のＣｏで構成されたＴａＣ、ＮｂＣ濃化領域）が形成され、ＴａＣ、ＮｂＣ濃化領域に隣接して、工具基体表面から最大深さ２〜６μｍの範囲にＣｏ貧化領域が形成されていることによって、ＣＦＲＰ等の難削材の高速高送りドリル穴開け切削加工において、すぐれた耐異常損傷性を示すとともに、長期の使用に亘ってすぐれた耐摩耗性を発揮している。 As is clear from the results of Tables 5 to 8, the drills 1 to 9 of the present invention have TaC and NbC enrichment regions (having a predetermined depth direction average length, average width, and predetermined generation density) in the vicinity of the tool base surface That is, it is surrounded by WC particles, and inside thereof, TaC and NbC enriched regions composed of one or two of TaC and NbC and 1.0% by mass or less of Co are formed, TaC, Adjacent to the NbC concentration region, the Co-poor region is formed in the maximum depth range of 2 to 6 μm from the tool base surface. In addition to exhibiting excellent abnormal damage resistance, it exhibits excellent wear resistance over a long period of use.
これに対して、本発明ドリルのようなＴａＣ、ＮｂＣ濃化領域が形成されていない比較ドリル１〜１２は、チッピング、欠損、剥離等の耐異常損傷性に劣り、短期に寿命に至ることが明らかである。 On the other hand, the comparative drills 1 to 12 in which the TaC and NbC enriched regions are not formed like the drill of the present invention are inferior to abnormal damage resistance such as chipping, chipping and peeling, and may reach a short life. it is obvious.
本発明のダイヤモンド被覆超硬合金製切削工具は、ダイヤモンド被覆超硬合金製ドリルばかりでなく、ダイヤモンド被覆超硬合金製インサート、ダイヤモンド被覆超硬合金製エンドミル等、各種のダイヤモンド被覆工具に適用できるものであり、すぐれた刃先強度と耐摩耗性を発揮することから、切削加工の省エネ化、低コスト化に十分満足に対応できるものであり、その産業上の利用可能性はきわめて大きい。 The diamond-coated cemented carbide cutting tool of the present invention is applicable not only to diamond-coated cemented carbide drills but also to various diamond-coated tools such as diamond-coated cemented carbide inserts and diamond-coated cemented carbide end mills. Since it exhibits excellent cutting edge strength and wear resistance, it can sufficiently satisfy energy saving and cost reduction in cutting, and its industrial applicability is extremely large.
１ ＴａＣ、ＮｂＣの内の１種または２種
２ ダイヤモンド膜
３ ＷＣ粒子
４ Ｃｏ貧化領域
５ 金属結合相
６ ＴａＣ、ＮｂＣ濃化領域
７ ダイヤモンド膜と工具基体都の界面近傍
８ ＴａＣ、ＮｂＣ濃化領域の基体表面と平行方向の幅
９ ＴａＣ、ＮｂＣ濃化領域の深さ方向の長さ
1 TaC or NbC 1 type or 2 type 2 Diamond film 3 WC particles 4 Co poor region 5 Metal bonded phase 6 TaC, NbC concentrated region 7 Near interface between diamond film and tool substrate 8 TaC, NbC concentrated Width in the direction parallel to the substrate surface of the region 9 Length in the depth direction of the TaC, NbC enriched region
Claims (1)
（ａ）前記工具基体表面から６μｍまでの深さ領域に、ＷＣ粒子で囲まれたＴａＣ、ＮｂＣ濃化領域が形成され、該ＴａＣ、ＮｂＣ濃化領域の内部は、ＴａＣ、ＮｂＣの内の１種または２種の平均合計含有量が全金属組成に対し５０質量％以上、及び平均含有量が１．０質量％以下のＣｏで構成され、
（ｂ）前記ＴａＣ、ＮｂＣ濃化領域の、深さ方向の平均長さは２〜６μｍであり、前記工具基体と平行な方向の平均幅は２〜６μｍであり、
（ｃ）前記ＴａＣ、ＮｂＣ濃化領域の、工具基体の縦断面について測定した前記ＴａＣ、ＮｂＣ濃化領域の単位面積当たりの生成密度は３０００〜１５０００個／ｍｍ２であり、
（ｄ）前記ＴａＣ、ＮｂＣ濃化領域に隣接し、工具基体表面からの最大深さが２〜６μｍの範囲には、エッチングによりＣｏが除去された、Ｃｏ量の平均合計含有量が１．０質量％以下であるＣｏ貧化領域が形成されていることを特徴とするダイヤモンド被覆超硬合金製切削工具。
Tungsten carbide having an average composition in which the average content of Co is 3 to 15 mass%, the average total content of one or two of TaC and NbC is 0.1 to 3.0 mass%, and the balance is WC In a diamond coated cemented carbide cutting tool in which a diamond film having an average film thickness of 3 to 30 μm is coated on the surface of a tool base made of a base cemented carbide,
(A) A TaC and NbC concentrated region surrounded by WC particles is formed in a depth region from the tool substrate surface to 6 μm, and the inside of the TaC and NbC concentrated region is one of TaC and NbC. The average total content of seeds or two types is composed of 50% by mass or more with respect to the total metal composition, and the average content is 1.0% by mass or less of Co,
(B) The average length in the depth direction of the TaC and NbC concentration region is 2 to 6 μm, the average width in the direction parallel to the tool base is 2 to 6 μm,
(C) The generation density per unit area of the TaC, NbC concentrated region measured from the longitudinal section of the tool base of the TaC, NbC concentrated region is 3000-15000 pieces / mm 2 ,
(D) Adjacent to the TaC and NbC enriched regions, the maximum depth from the surface of the tool base is in the range of 2 to 6 μm, and the average total content of Co is 1.0 by removing Co by etching. A diamond-coated cemented carbide cutting tool characterized in that a Co-poor region having a mass% or less is formed.
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