JP5898051B2

JP5898051B2 - Coated tool

Info

Publication number: JP5898051B2
Application number: JP2012259922A
Authority: JP
Inventors: 貴彦牧野; 藤崎　浩一; 浩一藤崎
Original assignee: Kyocera Corp
Current assignee: Kyocera Corp
Priority date: 2012-11-28
Filing date: 2012-11-28
Publication date: 2016-04-06
Anticipated expiration: 2032-11-28
Also published as: JP2014104545A

Description

本発明は被覆層を具備する被覆工具に関する。 The present invention relates to a coated tool having a coating layer.

従来から金属の切削加工に広く用いられている切削工具は、超硬合金等の基体の表面にＴｉＣＮ層やＡｌ_２Ｏ_３層等の多層の被覆層を被着形成したものが広く用いられている。また、インコネルやステンレス等の耐熱合金の需要の増加に伴って、耐熱合金の切削における切削性能に優れた切削工具が求められている。しかしながら、従来の切削工具では、切削時に切刃付近の温度が高温になる。その結果、切刃に熱亀裂が発生したり、発生した熱亀裂からクラックが進展したりして、切刃にチッピングや欠損が発生するという問題があった。 Conventionally, a cutting tool widely used for metal cutting is widely used in which a multilayer coating layer such as a TiCN layer or an Al ₂ O ₃ layer is deposited on the surface of a substrate such as cemented carbide. Yes. Moreover, with the increase in demand for heat-resistant alloys such as Inconel and stainless steel, a cutting tool having excellent cutting performance in cutting heat-resistant alloys is required. However, with a conventional cutting tool, the temperature near the cutting edge becomes high during cutting. As a result, there has been a problem that a thermal crack occurs in the cutting blade or a crack develops from the generated thermal crack, thereby causing chipping or chipping in the cutting blade.

そこで、特許文献１では、Ｃｏを１２．０〜１５．０ｗｔ％と、Ｃｒを０．５２〜０．６４ｗｔ％と、残部がＷＣとからなる超硬合金基体の表面に、合計厚さが１．９〜３．６μｍの第１〜第３のＴｉＣＮＯ層と、１．８〜３．６μｍの厚みの最表層Ａｌ_２Ｏ_３層とを被覆した切削工具フライスインサートが記載されている。 Therefore, in Patent Document 1, the total thickness is 1 on the surface of the cemented carbide substrate made of Co of 12.0 to 15.0 wt%, Cr of 0.52 to 0.64 wt%, and the balance of WC. A cutting tool milling insert coated with 1.9 to 3.6 μm first to third TiCNO layers and an outermost Al ₂ O ₃ layer with a thickness of 1.8 to 3.6 μm is described.

特開２００７−１６０５０４号公報JP 2007-160504 A

しかしながら、特許文献１のインサートでは、熱亀裂の発生を抑制する効果が不十分であり、被覆層が剥離するおそれがあった。 However, in the insert of Patent Document 1, the effect of suppressing the occurrence of thermal cracking is insufficient, and the coating layer may be peeled off.

本発明の目的は、耐熱合金の切削加工のように切刃が高温になる加工においても、切刃における熱亀裂の発生を抑制し、かつ被覆層の剥離の発生を抑えることができる切削工具を提供することにある。 An object of the present invention is to provide a cutting tool capable of suppressing the generation of thermal cracks in the cutting blade and the occurrence of peeling of the coating layer even in a processing where the cutting blade is at a high temperature, such as a heat-resistant alloy cutting. It is to provide.

本発明の被覆工具は、平均粒径０．９〜１．２μｍのＷＣ相を主体として、１０〜１５質量％のＣｏと、０．２〜０．６質量％のＣｒ_３Ｃ_２とを含有する超硬合金からなる基体の表面に、平均厚みが１〜３μｍのＴｉＣＮ層と、平均厚みが０．３〜０．７μｍのＡｌ_２Ｏ_３層と、が順に積層されてなるものである。 The coated tool of the present invention is mainly composed of a WC phase having an average particle size of 0.9 to 1.2 μm, and contains 10 to 15% by mass of Co and 0.2 to 0.6% by mass of Cr ₃ C _2. on the surface of the substrate made of cemented carbide, a TiCN layer having an average thickness of 1 to 3 [mu] m, and _{the Al} 2 _{O 3} layer having an average thickness of 0.3 to 0.7 [mu] m, but those obtained by laminating in this order.

本発明の被覆工具によれば、ＷＣ相の平均粒径とＣｏ含有量を難削材の加工に最適な範囲に調整して、切削時の発熱によっても熱亀裂およびその進展が抑制される。また、切刃が高温になっても、Ａｌ_２Ｏ_３層が被覆層の酸化を抑制する。しかも、Ａｌ_２Ｏ_３層の厚みは０．３〜０．７μｍなので、凝着しやすい耐熱合金の加工であってもＡｌ_２Ｏ_３層の剥離を抑制できる。 According to the coated tool of the present invention, the average particle size and Co content of the WC phase are adjusted to an optimum range for processing difficult-to-cut materials, and thermal cracks and their progress are suppressed by heat generation during cutting. Moreover, even if the cutting edge becomes high temperature, the Al ₂ O ₃ layer suppresses the oxidation of the coating layer. Moreover, the thickness of _{the Al} 2 _{O 3} layer can suppress separation of 0.3~0.7μm So adhesion easily _{the Al} 2 _{O 3} layer be processed heat-resistant alloy.

本発明の被覆工具の好適例である切削工具の概略断面図である。It is a schematic sectional drawing of the cutting tool which is a suitable example of the coating tool of this invention. 図１の切削工具の（ａ）切刃、（ｂ）すくい面における最表層の表面についての走査型電子顕微鏡（ＳＥＭ）写真である。It is a scanning electron microscope (SEM) photograph about the surface of the outermost layer in the (a) cutting edge and (b) rake face of the cutting tool of FIG. 図１の切削工具を成膜する際の試料のセット方法の一例を説明するための断面図であり、（ａ）切刃およびすくい面におけるＡｌ_２Ｏ_３層の厚みや最表層の結晶構造を異ならせるセット方法、（ｂ）一方の主面側のＡｌ_２Ｏ_３層の厚みと他方の主面側のＡｌ_２Ｏ_３層の厚みとを異ならせるセット方法の一例を示す模式図である。Is a sectional view for explaining an example of a method of setting the sample at the time of forming the cutting tool of FIG 1, the the Al ₂ O ₃ layer thickness and the outermost surface layer of the crystal structure in (a) cutting and the rake face set how varied is a schematic diagram showing an example of a set of methods to differentiate the thickness of the Al ₂ O ₃ layer thickness and the other main surface side of the Al ₂ O ₃ layer on one main surface (b).

本発明の被覆工具の好適例である切削工具１は、図１に示すように、基体２の表面に、ＴｉＮ層４と、ＴｉＣＮ層５と、中間層６と、Ａｌ_２Ｏ_３層７と、最表層８とが基体２側から順に形成された被覆層９が設けられている。また、図１によれば、Ａｌ_２Ｏ_３層７の表面に、ＴｉＣ_ｘＮ_ｙ層（０＜ｘ、０．５≦ｙ、ｘ＋ｙ＝１、以下単に最外層と称す）が最表層８として積層されている。被覆層９の各層の平均厚みは、ＴｉＮ層４が０．３〜０．７μｍ、ＴｉＣＮ層５が１〜３μｍ、中間層６が０．０１〜０．１μｍ、Ａｌ_２Ｏ_３層７が０．３〜０．７μｍ、最外層８が０．３〜０．７μｍである。なお、各層の平均厚みは、各層の任意の位置において１０μｍ以上の幅に亘って１μｍ間隔で厚みを測定し、その平均値を取って算出する。 As shown in FIG. 1, a cutting tool 1 which is a preferred example of the coated tool of the present invention has a TiN layer 4, a TiCN layer 5, an intermediate layer 6, and an Al ₂ O ₃ layer 7 on the surface of a base 2. In addition, a coating layer 9 is provided in which the outermost layer 8 is formed in order from the base 2 side. Further, according to FIG. 1, a TiC _x N _y layer (0 <x, 0.5 ≦ y, x + y = 1, hereinafter simply referred to as the outermost layer) is formed on the surface of the Al ₂ O ₃ layer 7 as the outermost layer 8. Are stacked. The average thickness of each layer of the covering layer 9 is 0.3 to 0.7 μm for the TiN layer 4, 1 to 3 μm for the TiCN layer 5, 0.01 to 0.1 μm for the intermediate layer 6, and 0 for the Al ₂ O ₃ layer 7. 3 to 0.7 μm, and the outermost layer 8 is 0.3 to 0.7 μm. The average thickness of each layer is calculated by measuring the thickness at an interval of 1 μm over a width of 10 μm or more at an arbitrary position of each layer, and taking the average value.

ここで、ＴｉＣＮ層５が１μｍよりも薄いと、十分な耐摩耗性を維持できない。逆に、ＴｉＣＮ層５が３μｍよりも厚いと、欠損しやすい。ＴｉＣＮ層５のより好適な範囲は、２〜２．５μｍである。Ａｌ_２Ｏ_３層７が０．３μｍよりも薄いと、十分な耐酸化性を維持できず、耐摩耗性が低下する。逆に、Ａｌ_２Ｏ_３層７が０．７μｍよりも厚いと、チッピングしやすい。Ａｌ_２Ｏ_３層７のより好適な範囲は、０．４〜０．６μｍである。 Here, if the TiCN layer 5 is thinner than 1 μm, sufficient wear resistance cannot be maintained. On the contrary, if the TiCN layer 5 is thicker than 3 μm, it is easily lost. A more preferable range of the TiCN layer 5 is 2 to 2.5 μm. If the Al ₂ O ₃ layer 7 is thinner than 0.3 μm, sufficient oxidation resistance cannot be maintained, and wear resistance decreases. On the contrary, if the Al ₂ O ₃ layer 7 is thicker than 0.7 μm, chipping is easy. A more preferable range of the Al ₂ O ₃ layer 7 is 0.4 to 0.6 μm.

また、基体２は、平均粒径０．９〜１．２μｍのＷＣ相を主体として、１０〜１５質量％のＣｏと、０．２〜０．６質量％のＣｒ_３Ｃ_２とを含有する超硬合金からなる。なお、ＷＣ相を主体とするとは、ＷＣを５０質量％以上含有する状態を指し、特に、好適な範囲としては、ＷＣを８４．４質量％以上含有しているものである。この基体２と被覆層９との組み合わせによって、切削時の発熱によっても熱亀裂およびその進展が抑制される。また、切刃が高温になっても、Ａｌ_２Ｏ_３層７が被覆層の酸化を抑制する。しかも、Ａｌ_２Ｏ_３層７の平均厚みは０．３〜０．７μｍなので、Ｎｉ基合金やＴｉ基合金のような凝着しやすい耐熱合金の加工であってもＡｌ_２Ｏ_３層７の剥離を抑制できる。 The substrate 2 mainly contains a WC phase having an average particle size of 0.9 to 1.2 μm and contains 10 to 15% by mass of Co and 0.2 to 0.6% by mass of Cr ₃ C _2. Made of cemented carbide. Note that “mainly composed of the WC phase” means a state containing 50 mass% or more of WC, and a particularly preferable range is that containing 84.4 mass% or more of WC. The combination of the substrate 2 and the covering layer 9 suppresses thermal cracks and their progress even by heat generated during cutting. Moreover, even if the cutting edge becomes high temperature, the Al ₂ O ₃ layer 7 suppresses oxidation of the coating layer. Moreover, the average thickness of _{the Al} 2 _{O 3} layer 7 so 0.3 to 0.7 [mu] m, even working of adhesion tends to heat resistant alloys such as Ni-based alloys and Ti-based alloys of _{the Al} 2 _{O 3} layer 7 Peeling can be suppressed.

ここで、ＷＣ相の平均粒径が０．９μｍよりも小さいと、靱性が低く、突発欠損しやすくなる。逆に、ＷＣ相の平均粒径が１．２μｍよりも大きいと、硬度が低下するため、十分な耐摩耗性を維持出来ない。ＷＣ相の平均粒径のより好適な範囲は、１．０〜１．１５μｍである。Ｃｏ含有量が１０質量％よりも少ないと、十分な靱性、強度が確保できず、欠損しやすい。逆に、Ｃｏ含有量が１５質量％よりも多いと、熱伝導率が低下し、熱亀裂が発生し欠損しやすいという不具合がある。Ｃｏ含有量のより好適な範囲は、１１〜１３質量％である。Ｃｒの含有量がＣｒ_３Ｃ_２換算で０．２質量％よりも少ないと、基体２が腐食しやすく被膜が剥離しやすい。逆に、Ｃｒ含有量がＣｒ_３Ｃ_２換算で０．６質量％よりも多いと、靱性が低下し欠損しやすくなる。ＣｒのＣｒ_３Ｃ_２換算量のより好適な範囲は、０．４〜０．５質量％である。 Here, if the average particle size of the WC phase is smaller than 0.9 μm, the toughness is low and sudden defects are likely to occur. On the other hand, if the average particle size of the WC phase is larger than 1.2 μm, the hardness decreases, so that sufficient wear resistance cannot be maintained. A more preferable range of the average particle diameter of the WC phase is 1.0 to 1.15 μm. If the Co content is less than 10% by mass, sufficient toughness and strength cannot be ensured, and defects are likely to occur. On the other hand, when the Co content is more than 15% by mass, there is a problem that the thermal conductivity is lowered and thermal cracks are easily generated and are lost. A more preferable range of the Co content is 11 to 13% by mass. When the content of Cr is less than 0.2% by mass in terms of Cr ₃ C ₂ , the substrate 2 is easily corroded and the coating is easily peeled off. On the other hand, when the Cr content is more than 0.6% by mass in terms of Cr ₃ C ₂ , the toughness is lowered and defects are likely to occur. More preferable range of _Cr 3 _{C 2} in terms of Cr is 0.4 to 0.5 mass%.

また、ＴｉＮ層４は基体２と被覆層９との密着性を高めるものであり、ＴｉＮ層４の平均厚みが０．３〜０．７μｍであると、被覆層９は基体２との密着性が良く、かつ、被覆層９はチッピングしにくい。ＴｉＮ層４のより好適な範囲は、０．４〜０．５μｍである。さらに、ＴｉＣＮ層５とＡｌ_２Ｏ_３層７との間にはＴｉＣＯ、ＴｉＮＯおよびＴｉＣＮＯのうちのいずれかからなる中間層６が設けられており、中間層６はＴｉＣＮ層５とＡｌ_２Ｏ_３層７との密着性を高めることができる。中間層６の平均厚みが０．０１〜０．１μｍであると、Ａｌ_２Ｏ_３層７が剥離しにくく、かつＡｌ_２Ｏ_３層７がチッピングしにくい。中間層６のより好適な範囲は、０．０３〜０．０８μｍである。 Further, the TiN layer 4 enhances the adhesion between the substrate 2 and the coating layer 9. When the average thickness of the TiN layer 4 is 0.3 to 0.7 μm, the coating layer 9 adheres to the substrate 2. The covering layer 9 is difficult to chip. A more preferable range of the TiN layer 4 is 0.4 to 0.5 μm. Further, an intermediate layer 6 made of any one of TiCO, TiNO and TiCNO is provided between the TiCN layer 5 and the Al ₂ O ₃ layer 7, and the intermediate layer 6 is composed of the TiCN layer 5 and the Al ₂ O ₃ layer. Adhesion with the layer 7 can be enhanced. When the average thickness of the intermediate layer 6 is 0.01 to 0.1 μm, the Al ₂ O ₃ layer 7 is difficult to peel off and the Al ₂ O ₃ layer 7 is difficult to chip. A more preferable range of the intermediate layer 6 is 0.03 to 0.08 μm.

なお、最外層８は、ＴｉＣ_ｘＮ_ｙ層（０＜ｘ、０．５≦ｙ、ｘ＋ｙ＝１）からなり、切削工具１の表面を金色として、切刃の未使用、使用済みの判定を容易にするために設けたものであり、０．３〜０．７μｍであれば、目視で識別できる。また、本実施態様では、図２に示すように、最表層８の表面において、切刃ではＴｉＣ_ｘＮ_ｙ結晶（０＜ｘ、０．５≦ｙ、ｘ＋ｙ＝１）が粒状粒子からなるとともに、すくい面では針状粒子からなる。これによって、切刃においては、被覆層９の表面での空隙が少なく、被覆層９の摩耗が小さい。一方、すくい面では被覆層９の表面に針状粒子が析出した構造なので、被覆層９の表面での空隙が多いので、被覆層９の表面における切削液の保持力が向上する。その結果、加工によって発生する切屑の流れがスムーズになり、切刃における温度上昇を抑制することができる。なお、最表層８には、酸素を全量中１０質量％以下の割合で含有してもよい。 The outermost layer 8 is made of a TiC _x N _y layer (0 <x, 0.5 ≦ y, x + y = 1). The surface of the cutting tool 1 is gold, and the cutting blade is judged as unused or used. It is provided for the sake of ease. If it is 0.3 to 0.7 μm, it can be visually identified. Further, in this embodiment, as shown in FIG. 2, on the surface of the outermost layer 8, TiC _x N _y crystals (0 <x, 0.5 ≦ y, x + y = 1) are formed of granular particles at the cutting edge. The rake face consists of acicular particles. As a result, in the cutting edge, there are few voids on the surface of the coating layer 9, and wear of the coating layer 9 is small. On the other hand, since the acicular particles are deposited on the surface of the coating layer 9 on the rake face, there are many voids on the surface of the coating layer 9, so that the retention of cutting fluid on the surface of the coating layer 9 is improved. As a result, the flow of chips generated by machining becomes smooth, and the temperature rise at the cutting edge can be suppressed. The outermost layer 8 may contain oxygen at a ratio of 10% by mass or less in the total amount.

さらに、本実施態様では、最表層８は、基体側の炭素濃度が表面側の炭素濃度よりも高い構成となっている。これによって、すくい面においては、針状粒子が形成されるとともに、最表層８の表面では金色になり、使用の識別がしやすい。 Furthermore, in the present embodiment, the outermost layer 8 has a structure in which the carbon concentration on the substrate side is higher than the carbon concentration on the surface side. As a result, acicular particles are formed on the rake face, and the surface of the outermost layer 8 is gold, making it easy to identify the use.

また、図１の切削工具１の全体形状は、概略板形状で、主面に対して側面が９０°であり、両主面の端部を切刃として使用する形状、いわゆる、両面使いのネガチップ形状が好適例として挙げられる。そして、両主面は同じ形状からなるものであってもよいが、他の実施態様として、一方の主面側のＡｌ_２Ｏ_３層７の平均厚みと他方の主面側のＡｌ_２Ｏ_３層７の平均厚みとが異なっている構成であってもよい。この構成であれば、２つの加工条件で切削加工を行うような場合に、一方の主面側の切刃と他方の主面側の切刃を別々の加工条件で使い分けすることにより、切削工具はより最適な工具性能を発揮する。なお、このとき、より最適な工具性能とするために、一方の主面側のブレーカ形状と他方の主面側のブレーカ形状とが異なっていてもよい。 Further, the overall shape of the cutting tool 1 of FIG. 1 is a substantially plate shape, the side surface is 90 ° with respect to the main surface, and a shape that uses the ends of both main surfaces as cutting edges, a so-called double-sided negative chip. A shape is mentioned as a suitable example. And although both main surfaces may consist of the same shape, as another embodiment, the average thickness of the Al ₂ O ₃ layer 7 on one main surface side and the Al ₂ O ₃ on the other main surface side. The structure from which the average thickness of the layer 7 differs may be sufficient. With this configuration, when cutting is performed under two processing conditions, a cutting tool is used by properly using one main surface side cutting blade and the other main surface side cutting blade under different processing conditions. Provides more optimal tool performance. At this time, the breaker shape on the one main surface side and the breaker shape on the other main surface side may be different in order to obtain a more optimal tool performance.

さらに、上記切削工具１は、すくい面と逃げ面との交差部に形成された切刃を被切削物に当てて切削加工するが、本発明の被覆工具は、これに限定されるものではなく、切削工具１以外にも、摺動部品や金型等の耐摩部品、掘削工具、刃物等の工具、耐衝撃部品等の各種の用途へ応用可能であり、この場合にも優れた機械的信頼性を有するものである。 Furthermore, although the said cutting tool 1 cuts by applying the cutting blade formed in the intersection of a rake face and a flank to a to-be-cut object, the coated tool of this invention is not limited to this. In addition to the cutting tool 1, it can be applied to various applications such as wear parts such as sliding parts and molds, tools such as excavation tools, blades, and impact resistant parts. It has sex.

（製造方法）
本発明の被覆工具を作製する方法について説明する。
まず、基体２となる硬質合金を焼成によって形成しうる金属炭化物、窒化物、炭窒化物、酸化物等の無機物粉末に、金属粉末、カーボン粉末等を適宜添加、混合し、プレス成形、鋳込成形、押出成形、冷間静水圧プレス成形等の公知の成形方法によって所定の工具形状に成形した後、真空中または非酸化性雰囲気中にて焼成することによって上述した硬質合金からなる基体２を作製する。そして、上記基体２の表面に所望によって研磨加工や切刃部のホーニング加工を施す。 (Production method)
A method for producing the coated tool of the present invention will be described.
First, metal powder, carbon powder, etc. are appropriately added to and mixed with inorganic powders such as metal carbides, nitrides, carbonitrides, oxides, etc. that can form a hard alloy to be the base 2 by firing, press molding, casting After forming into a predetermined tool shape by a known molding method such as molding, extrusion molding, cold isostatic pressing, etc., the substrate 2 made of the hard alloy described above is fired in a vacuum or non-oxidizing atmosphere. Make it. Then, the surface of the base 2 is subjected to polishing or honing of the cutting edge as desired.

そして、その表面に化学気相蒸着（ＣＶＤ）法によって表面被覆層を成膜する。
まず、反応ガス組成として四塩化チタン（ＴｉＣｌ_４）ガスを０．５〜１０体積％、窒素（Ｎ_２）ガスを１０〜６０体積％、残りが水素（Ｈ_２）ガスからなる混合ガスを調整して反応チャンバ内に導入し、チャンバ内を８００〜９４０℃、８〜５０ｋＰａの条件でＴｉＮ層４を成膜する。 Then, a surface coating layer is formed on the surface by chemical vapor deposition (CVD).
First, a mixed gas composed of 0.5 to 10% by volume of titanium tetrachloride (TiCl ₄ ) gas, 10 to 60% by volume of nitrogen (N ₂ ) gas, and the balance of hydrogen (H ₂ ) gas is prepared as a reaction gas composition. Then, it is introduced into the reaction chamber, and the TiN layer 4 is formed in the chamber under conditions of 800 to 940 ° C. and 8 to 50 kPa.

次に、反応ガス組成として、体積％で四塩化チタン（ＴｉＣｌ_４）ガスを０．５〜１０体積％、窒素（Ｎ_２）ガスを１０〜６０体積％、アセトニトリル（ＣＨ_３ＣＮ）ガスを０．１〜３．０体積％、残りが水素（Ｈ_２）ガスからなる混合ガスを調整して反応チャンバ
内に導入し、成膜温度を７８０〜８８０℃、５〜２５ｋＰａにてＴｉＣＮ層５の下側部分を成膜する。ここで、上記成膜条件のうち、反応ガス中のアセトニトリルガスの割合が０．１〜０．４体積％に調整すること、および成膜温度を７８０℃〜８８０℃とすることが、断面観察において下側部分が微細な筋状晶（ＭＴ−ＴｉＣＮ）からなるＴｉＣＮ層５を形成できるために望ましい。 Next, as a reaction gas composition, titanium tetrachloride (TiCl ₄ ) gas is 0.5 to 10% by volume, nitrogen (N ₂ ) gas is 10 to 60% by volume, and acetonitrile (CH ₃ CN) gas is 0% by volume. A mixed gas composed of 0.1 to 3.0% by volume and the remainder consisting of hydrogen (H ₂ ) gas was prepared and introduced into the reaction chamber, and the TiCN layer 5 was formed at a film formation temperature of 780 to 880 ° C. and 5 to 25 kPa. The lower part is deposited. Here, of the above film forming conditions, the ratio of acetonitrile gas in the reaction gas is adjusted to 0.1 to 0.4% by volume, and the film forming temperature is set to 780 ° C. to 880 ° C. In this case, the lower portion is desirable because the TiCN layer 5 made of fine streaks (MT-TiCN) can be formed.

なお、ＴｉＣＮ層５の下側部分の成膜条件は単一条件で形成しても良いが、ＴｉＣＮ層の成膜条件を途中で変更して組織状態を変えることもできる。例えば、アセトニトリル（ＣＨ_３ＣＮ）ガスの比率を増してＴｉＣＮ層５の上側の結晶を下側の結晶よりも幅の広い柱状結晶とすることができる。または、上記ＴｉＣＮ層５の成膜途中から、成膜条件を、四塩化チタン（ＴｉＣｌ_４）ガスを１〜５体積％、メタン（ＣＨ_４）ガスを４〜１０体積％、窒素（Ｎ_２）ガスを１０〜３０体積％、残りが水素（Ｈ_２）ガスからなる混合ガスを調整して反応チャンバ内に導入し、チャンバ内を９５０〜１１００℃、５〜４０ｋＰａの条件に変更することによって、ＴｉＣＮ層５の上側の結晶を下側の結晶よりも幅の広い柱状結晶とすることができる。この条件において、メタン（ＣＨ_４）ガスの代わりにアセトニトリル（ＣＨ_３ＣＮ）ガスを０．５〜５体積％の割合で使用しても所望のＴｉＣＮ層５の形成が可能である。 In addition, although the film-forming conditions of the lower part of the TiCN layer 5 may be formed under a single condition, the film-forming conditions of the TiCN layer can be changed in the middle to change the structure state. For example, the ratio of acetonitrile (CH ₃ CN) gas can be increased to make the upper crystal of the TiCN layer 5 into a columnar crystal having a width wider than that of the lower crystal. Alternatively, during the film formation of the TiCN layer 5, the film formation conditions are as follows: titanium tetrachloride (TiCl ₄ ) gas is 1 to 5% by volume, methane (CH ₄ ) gas is 4 to 10% by volume, and nitrogen (N ₂ ). By adjusting a mixed gas consisting of 10 to 30% by volume of gas and the remainder consisting of hydrogen (H ₂ ) gas into the reaction chamber and changing the inside of the chamber to 950 to 1100 ° C. and 5 to 40 kPa, The upper crystal of the TiCN layer 5 can be a columnar crystal that is wider than the lower crystal. Under this condition, the desired TiCN layer 5 can be formed even if acetonitrile (CH ₃ CN) gas is used in a proportion of 0.5 to 5% by volume instead of methane (CH ₄ ) gas.

次に、ＴｉＣＮ層５の上側部分を構成するＨＴ−ＴｉＣＮ層を成膜する。ＨＴ−ＴｉＣＮ層の具体的な成膜条件は、四塩化チタン（ＴｉＣｌ_４）ガスを２．５〜４体積％、メタン（ＣＨ_４）ガスを０．１〜１０体積％、窒素（Ｎ_２）ガスを５〜２０体積％、残りが水素（Ｈ_２）ガスからなる混合ガスを調整して反応チャンバ内に導入し、チャンバ内を９００〜１０５０℃、５〜４０ｋＰａとし、成膜時間を２０〜６０分とすることが望ましい。 Next, an HT-TiCN layer constituting the upper part of the TiCN layer 5 is formed. The specific film formation conditions of the HT-TiCN layer are as follows: titanium tetrachloride (TiCl ₄ ) gas is 2.5 to ₄ % by volume, methane (CH ₄ ) gas is 0.1 to 10% by volume, and nitrogen (N ₂ ). A gas mixture of 5 to 20% by volume and the remainder consisting of hydrogen (H ₂ ) gas was prepared and introduced into the reaction chamber, the inside of the chamber was set to 900 to 1050 ° C. and 5 to 40 kPa, and the film formation time was 20 to 20%. 60 minutes is desirable.

さらに、中間層６を作製する。具体的な成膜条件は、四塩化チタン（ＴｉＣｌ_４）ガスを１〜４体積％、メタン（ＣＨ_４）ガスを０〜７体積％、窒素（Ｎ_２）ガスを０〜２０体積％、二酸化炭素（ＣＯ_２）ガスを１〜５体積％、残りが水素（Ｈ_２）ガスからなる混合ガスを調整する。これらの混合ガスを調整して反応チャンバ内に導入し、チャンバ内を９００〜１０５０℃、５〜４０ｋＰａとし、成膜時間を２０〜６０分とする条件で成膜する。 Further, the intermediate layer 6 is produced. Specific film forming conditions, titanium tetrachloride (TiCl ₄₎ 1 to 4% by volume of the gas, methane (CH ₄₎ gas 0-7% by volume, nitrogen _{(N 2)} 0 to 20% by volume of the gas, dioxide A mixed gas composed of 1 to 5% by volume of carbon (CO ₂ ) gas and the remaining hydrogen (H ₂ ) gas is prepared. These mixed gases are adjusted and introduced into the reaction chamber, and the film is formed under the conditions of 900 to 1050 ° C., 5 to 40 kPa, and a film formation time of 20 to 60 minutes.

そして、引き続き、Ａｌ_２Ｏ_３層７を成膜する。Ａｌ_２Ｏ_３層７の成膜方法としては、三塩化アルミニウム（ＡｌＣｌ_３）ガスを０．５〜５．０体積％、塩化水素（ＨＣｌ）ガスを０．５〜３．５体積％、二酸化炭素（ＣＯ_２）ガスを０．５〜５．０体積％、硫化水素（Ｈ_２Ｓ）ガスを０．０〜０．５体積％、残りが水素（Ｈ_２）ガスからなる混合ガスを用い、９５０〜１１００℃、５〜１０ｋＰａとすることが望ましい。 Subsequently, an Al ₂ O ₃ layer 7 is formed. As a method of forming the Al ₂ O ₃ layer 7, aluminum trichloride (AlCl ₃ ) gas is 0.5 to 5.0% by volume, hydrogen chloride (HCl) gas is 0.5 to 3.5% by volume, dioxide dioxide. A mixed gas composed of 0.5 to 5.0% by volume of carbon (CO ₂ ) gas, 0.0 to 0.5% by volume of hydrogen sulfide (H ₂ S) gas, and the remaining hydrogen (H ₂ ) gas is used. 950-1100 ° C., 5-10 kPa is desirable.

また、所望により、最表層８を成膜する。具体的な成膜条件は、反応ガス組成として四塩化チタン（ＴｉＣｌ_４）ガスを０．１〜１０体積％、窒素（Ｎ_２）ガスを０〜６０体積％、残りが水素（Ｈ_２）ガスからなる混合ガスを調整して反応チャンバ内に導入し、チャンバ内を９６０〜１１００℃、１０〜８５ｋＰａとすればよい。 Further, the outermost layer 8 is formed as desired. Specific film forming conditions are as follows: titanium tetrachloride (TiCl ₄ ) gas is 0.1 to 10% by volume, nitrogen (N ₂ ) gas is 0 to 60% by volume, and the remainder is hydrogen (H ₂ ) gas. The mixed gas consisting of the above may be adjusted and introduced into the reaction chamber, and the inside of the chamber may be set to 960 to 1100 ° C. and 10 to 85 kPa.

上記被覆層９の成膜においては、試料をセットする状態を制御する。図３（ａ）に示すように、セットプレート１７に略棒状の支柱１１を立てて、支柱１１に略円錐状または円筒状のスペーサ１４を挿入し、その後、支柱１１に基体２である試料１２（１２ａ）のネジ孔１３を貫通させてスペーサ１４も貫通した状態で載置する。次に、スペーサ１４を挿入して、次の試料１２（１２ｂ）を挿入し、このスペーサ１４が介在した状態で２つの試料１２（１２ｂ）を載置する。このとき、２つの試料の対向するすくい面同士が全体的に平行となるようにし、２つの試料のすくい面の間隔ｄが０．５〜１ｍｍとなるように調整する。このようにして複数の試料をセットする。そして、最も上部に位置する試料の上に
は、ダミー試料１６を載置する。また、下段の試料とセットプレート１７との間隔も０．５〜１．０ｍｍに制御する。この状態で成膜することによって、切刃およびすくい面におけるＡｌ_２Ｏ_３層の厚みや最表層の結晶構造を異ならせることができる。 In forming the coating layer 9, the state of setting the sample is controlled. As shown in FIG. 3 (a), a substantially rod-like column 11 is erected on the set plate 17, a substantially conical or cylindrical spacer 14 is inserted into the column 11, and then the sample 12 that is the base 2 is inserted into the column 11. The screw hole 13 of (12a) is penetrated and the spacer 14 is also penetrated. Next, the spacer 14 is inserted, the next sample 12 (12b) is inserted, and the two samples 12 (12b) are placed with the spacer 14 interposed. At this time, the rake faces of the two samples facing each other are generally parallel to each other, and the distance d between the rake faces of the two samples is adjusted to be 0.5 to 1 mm. In this way, a plurality of samples are set. A dummy sample 16 is placed on the uppermost sample. Further, the distance between the lower sample and the set plate 17 is also controlled to 0.5 to 1.0 mm. By forming the film in this state, the thickness of the Al ₂ O ₃ layer and the crystal structure of the outermost layer on the cutting edge and the rake face can be varied.

また、一方の主面側のＡｌ_２Ｏ_３層７の厚みと他方の主面側のＡｌ_２Ｏ_３層７の厚みとを異ならせるには、図３（ｂ）に示すように、下段の試料１２とセットプレートとの間隔を１．０ｍｍよりも広くするとともに、上記支柱１１に試料１２を２つだけセットし、最も上部に位置する試料の上には、ダミー試料を載置しない。この状態で成膜することによって、一方の主面側のＡｌ_２Ｏ_３層７の厚みと他方の主面側のＡｌ_２Ｏ_３層７の厚みとを異ならせることができる。このとき、対向するすくい面に設けられるブレーカ形状と、対向しないすくい面に設けられるブレーカ形状とを異ならせることによって、得られた切削工具は、両面を異なる切削条件で使うことができる。 Further, in order different from the one main surface side of the thickness of the Al ₂ O ₃ layer 7 thickness and the other main surface side the Al ₂ O ₃ layer 7, as shown in FIG. 3 (b), lower While the interval between the sample 12 and the set plate is made wider than 1.0 mm, only two samples 12 are set on the column 11, and no dummy sample is placed on the uppermost sample. By forming the film in this state, the thickness of the Al ₂ O ₃ layer 7 on one main surface side can be made different from the thickness of the Al ₂ O ₃ layer 7 on the other main surface side. At this time, by making the shape of the breaker provided on the opposing rake face different from the shape of the breaker provided on the non-facing rake face, the obtained cutting tool can be used on both sides under different cutting conditions.

炭化タングステン（ＷＣ）粉末に対して、平均粒径１．２μｍの金属コバルト（Ｃｏ）粉末および平均粒径２．５μｍのＣｒ_３Ｃ_２粉末とを添加、混合して、プレス成形により切削工具形状に成形した後、脱バインダ処理を施し、０．５〜１００Ｐａの真空中、１４００℃で１時間焼成して、表１に示す超硬合金を作製した。さらに、作製した超硬合金にブラスト加工にてすくい面側について刃先処理（Ｒホーニング）を施した。 To tungsten carbide (WC) powder, metal cobalt (Co) powder with an average particle diameter of 1.2 μm and Cr ₃ C ₂ powder with an average particle diameter of 2.5 μm are added and mixed, and then the cutting tool shape is formed by press molding. After being molded, the binder removal treatment was performed, and firing was performed at 1400 ° C. for 1 hour in a vacuum of 0.5 to 100 Pa to produce cemented carbides shown in Table 1. Furthermore, the cutting edge processing (R honing) was given to the rake face side by blasting to the manufactured cemented carbide.

次に、上記超硬合金に対して、ＣＶＤ法により被覆層を成膜した。試料は、図３（ａ）に示すように、セットプレートに立てた略棒状の支柱にスペーサを挿入した状態で試料のネジ孔を貫通させてスペーサ上に載置し、略円錐状のスペーサを介在させて次の試料を載置し、試料をセットプレートにセットした。このとき、２つの試料の対向するすくい面同士が全体的に平行となるようにし、２つの試料のすくい面の間隔が表１の間隔となるように調整した。そして、最も上部に位置する試料の上には、ダミー試料を載置した。また、下段の試料とセットプレートとの間隔も表１の間隔となるように調整した。 Next, a coating layer was formed on the cemented carbide by a CVD method. As shown in FIG. 3A, the sample is placed on the spacer through the screw hole of the sample in a state where the spacer is inserted into a substantially rod-like column that stands on the set plate. The next sample was placed therewith, and the sample was set on a set plate. At this time, the rake faces of the two samples facing each other were adjusted to be parallel to each other, and the distance between the rake faces of the two samples was adjusted to the distance shown in Table 1. A dummy sample was placed on the uppermost sample. In addition, the distance between the lower sample and the set plate was adjusted to the distance shown in Table 1.

成膜条件は、まず、８８０℃、１６ｋＰａの成膜条件で、ＴｉＣｌ_４：２．０体積％、Ｎ_２：３３体積％、残りがＨ_２の混合ガスを流してＴｉＮ層を成膜した。次に、８２５℃、９ｋＰａの成膜条件で、ＴｉＣｌ_４：２．５体積％、Ｎ_２：２３体積％、ＣＨ_３ＣＮ：０．４体積％、残りがＨ_２の混合ガスを流して平均結晶幅が０．３μｍの第１のＴｉＣＮ層を成膜した後、混合ガスをＴｉＣｌ_４：２．５体積％、Ｎ_２：１０体積％、ＣＨ_３ＣＮ：０．９体積％、残りがＨ_２に切り替えて、平均結晶幅が０．７μｍの第２のＴｉＣＮ層を成膜した。続いて、１０１０℃、２０ｋＰａの成膜条件で、ＴｉＣｌ_４：３．５体積％、ＣＨ_４：７体積％、Ｎ_２：１０体積％、残りがＨ_２の混合ガスを流して第３のＴｉＣＮ層を形成した。表中には、第１〜第３のＴｉＣＮ層の総厚みをＴｉＣＮ層の平均厚みとして示した。 The film formation conditions were as follows. First, a TiN layer was formed by flowing a mixed gas of TiCl ₄ : 2.0% by volume, N ₂ : 33% by volume, and the remainder H _{2 under} the conditions of 880 ° C. and 16 kPa. Next, under film formation conditions of 825 ° C. and 9 kPa, a mixed gas of TiCl ₄ : 2.5% by volume, N ₂ : 23% by volume, CH ₃ CN: 0.4% by volume, and the balance is H ₂ is averaged. After the first TiCN layer having a crystal width of 0.3 μm was formed, the mixed gas was TiCl ₄ : 2.5% by volume, N ₂ : 10% by volume, CH ₃ CN: 0.9% by volume, and the rest was H _{Then, a second} TiCN layer having an average crystal width of 0.7 μm was formed. Subsequently, under the film forming conditions of 1010 ° C. and 20 kPa, a third TiCN was supplied by flowing a mixed gas of TiCl ₄ : 3.5% by volume, CH ₄ : 7% by volume, N ₂ : 10% by volume, and the remaining H _2. A layer was formed. In the table, the total thickness of the first to third TiCN layers is shown as the average thickness of the TiCN layer.

そして、１０１０℃、２０ｋＰａの成膜条件で、ＴｉＣｌ_４：３．５体積％、ＣＨ_４：０〜３体積％、Ｎ_２：０〜１０体積％、ＣＯ_２：２体積％、残りがＨ_２の混合ガスを流して中間層を形成した。その後、１００５℃、９ｋＰａの成膜条件で、ＡｌＣｌ_３：１．５体積％、ＨＣｌ：２体積％、ＣＯ_２：４体積％、Ｈ_２Ｓ：０．３体積％、残りがＨ_２の混合ガスを流してαＡｌ_２Ｏ_３層を成膜した。最後に、１０１０℃、３０Ｐａの成膜条件で、ＴｉＣｌ_４：３．０体積％、Ｎ_２：３０体積％、残りがＨ_２の混合ガスを流して最表層を成膜した。最表層については、ＴｉＮを基本とする組成であったが、炭素（Ｃ）の拡散等による混入があったために、表中にはＴｉ（ＣＮ）と表記した。 And under film-forming conditions of 1010 ° C. and 20 kPa, TiCl ₄ : 3.5% by volume, CH ₄ : 0 to 3% by volume, N ₂ : 0 to 10% by volume, CO ₂ : 2% by volume, and the rest is H _2. Then, an intermediate layer was formed. Thereafter, a mixture of AlCl ₃ : 1.5% by volume, HCl: 2% by volume, CO ₂ : 4% by volume, H ₂ S: 0.3% by volume, and the remaining H ₂ under the film forming conditions of 1005 ° C. and 9 kPa. An αAl ₂ O ₃ layer was formed by flowing a gas. Finally, under the film forming conditions of 1010 ° C. and 30 Pa, the outermost layer was formed by flowing a mixed gas of TiCl ₄ : 3.0% by volume, N ₂ : 30% by volume, and the remaining H ₂ . The outermost layer had a composition based on TiN. However, since it was mixed due to carbon (C) diffusion or the like, it was represented as Ti (CN) in the table.

得られた切削工具について、表１、２に記載する被覆層が観察できるように機械研磨およびイオンミリングによる研磨加工を実施し、断面を露出させた。各層の断面に略垂直な
方向からみた各層のミクロな組織状態を観察し、平均厚みを測定した。そして、エネルギー分散型Ｘ線分光法（ＥＤＳ）、電子エネルギー損失分光法（ＥＥＬＳ）などにより、最表層に存在する原子種の確認、組成等についても観察した。結果は表１、２に示した。 About the obtained cutting tool, the grinding | polishing process by mechanical grinding | polishing and ion milling was implemented so that the coating layer described in Table 1, 2 could be observed, and the cross section was exposed. The microstructural state of each layer viewed from the direction substantially perpendicular to the cross section of each layer was observed, and the average thickness was measured. Then, confirmation of the atomic species existing in the outermost layer, composition, and the like were also observed by energy dispersive X-ray spectroscopy (EDS), electron energy loss spectroscopy (EELS), and the like. The results are shown in Tables 1 and 2.

そして、この切削工具を用いて下記の条件により、切削試験を行い、耐欠損性を評価した。結果は表２に示した。
（切削条件）
被削材：インコネル７１８角材
工具形状：ＰＮＭＵ１２０５ＡＮＥＲ−ＳＭ（京セラ株式会社製インサート）
切削速度：４０ｍ／分
送り速度：０．１５ｍｍ／刃
切り込み：２．０ｍｍ（軸方向）×１０ｍｍ（径方向）
その他：水溶性切削液使用
評価項目：欠損に至るまでの時間および切刃の状態 Then, using this cutting tool, a cutting test was performed under the following conditions to evaluate fracture resistance. The results are shown in Table 2.
(Cutting conditions)
Work material: Inconel 718 Square tool shape: PNMU1205ANER-SM (Kyocera Corporation insert)
Cutting speed: 40 m / min Feed rate: 0.15 mm / blade cutting: 2.0 mm (axial direction) × 10 mm (radial direction)
Others: Use of water-soluble cutting fluid Evaluation items: Time to failure and state of cutting edge

表１、２より、ＷＣ相の平均粒径が０．９μｍよりも小さい試料Ｎｏ．１２では、靱性が低く、突発欠損した。ＷＣ相の平均粒径が１．２μｍよりも大きい試料Ｎｏ．１３では、摩耗が大きくなった。Ｃｏ含有量が１０質量％よりも少ない試料Ｎｏ．１４では、欠損した。逆に、Ｃｏ含有量が１５質量％よりも多い試料Ｎｏ．１５では、熱亀裂による欠損が発生した。Ｃｒ_３Ｃ_２含有量が０．２質量％よりも少ない試料Ｎｏ．１６では、基体から被覆層が剥離した。Ｃｒ_３Ｃ_２含有量が０．６質量％よりも多い試料Ｎｏ．１７では、靱性が低下し欠損した。ＴｉＣＮ層の平均厚みが１μｍよりも薄い試料Ｎｏ．１８では、摩耗が大きくなった。ＴｉＣＮ層の平均厚みが３μｍよりも厚い試料Ｎｏ．１９では、欠損が発生した。Ａｌ_２Ｏ_３層の平均厚みが０．３μｍよりも薄い試料Ｎｏ．２０では、摩耗が大きかった。Ａｌ_２Ｏ_３層の平均厚みが０．７μｍよりも厚い試料Ｎｏ．２１では、チッピングが発生した。 From Tables 1 and 2, Sample No. with an average particle diameter of WC phase smaller than 0.9 μm. In No. 12, the toughness was low and sudden loss occurred. Sample No. with an average particle size of WC phase larger than 1.2 μm. In No. 13, wear increased. Sample No. with a Co content of less than 10% by mass 14 was deficient. Conversely, Sample No. with a Co content of more than 15% by mass was obtained. In 15, defects due to thermal cracks occurred. Sample No. with a Cr ₃ C ₂ content of less than 0.2% by mass. In No. 16, the coating layer peeled from the substrate. Sample No. with a Cr ₃ C ₂ content of more than 0.6 mass%. In No. 17, the toughness was reduced and lost. Sample No. with an average thickness of TiCN layer less than 1 μm In 18, the wear increased. Sample No. in which the average thickness of the TiCN layer is thicker than 3 μm In 19, a defect occurred. Sample No. _{2 in which} the average thickness of the Al ₂ O ₃ layer is thinner than 0.3 μm. In No. 20, the wear was large. Sample No. _{2 in which} the average thickness of the Al ₂ O ₃ layer is thicker than 0.7 μm. In No. 21, chipping occurred.

これに対して、本発明の範囲内である基体と被覆層とからなる試料Ｎｏ．１〜１１では、チッピングや欠損が抑制され、かつ摩耗の進行も抑制されていた。 On the other hand, sample No. consisting of a substrate and a coating layer within the scope of the present invention. In Nos. 1 to 11, chipping and chipping were suppressed, and progress of wear was also suppressed.

実施例１の試料Ｎｏ．１の基体と同じ材質を用いて、一方の主面に京セラ株式会社製ＰＮＭＵ１２０５ＡＮＥＲ−ＧＭブレーカが設けられ、他の主面に京セラ株式会社製ＰＮＭＵ１２０５ＡＮＥＲ−ＳＭブレーカが設けられた２つの試料を準備した。そして、２つの
試料の一方の主面同士を対向させて０．８ｍｍの間隔にして図３（ｂ）のような状態でセットして、試料Ｎｏ．１のＣＶＤ膜を成膜した。得られた切削工具の断面を走査型電子顕微鏡にて観察したところ、一方の主面におけるＡｌ_２Ｏ_３層の平均厚みは０．６μｍ、他方の主面におけるＡｌ_２Ｏ_３層の平均厚みは０．５μｍであった。この試料の両面を使って、耐酸化性が要求される下記切削条件にて切削評価を行ったところ、ＧＭブレーカを形成した切刃では切削可能時間が１４分であり、ＳＭブレーカを形成した切刃では切削可能時間が１０分であり、この切削条件ではＧＭブレーカ側の切刃の仕様がより優れた切削性能を示すことがわかった。
（切削条件）
被削材：インコネル７１８角材
工具形状：ＰＮＭＵ１２０５ＡＮＥＲ−ＧＭ／ＳＭ（京セラ株式会社製インサート）
切削速度：４０ｍ／分
送り速度：０．２５ｍｍ／刃
切り込み：２．０ｍｍ（軸方向）×１０ｍｍ（径方向）
その他：水溶性切削液使用 Sample No. 1 of Example 1 Two samples were prepared using the same material as the base of 1 and provided with a PNMU1205ANER-GM breaker manufactured by Kyocera Corporation on one main surface and a PNMU1205ANER-SM breaker manufactured by Kyocera Corporation on the other main surface. . Then, the main surfaces of one of the two samples are opposed to each other with an interval of 0.8 mm and set in the state as shown in FIG. 1 CVD film was formed. When the cross section of the obtained cutting tool was observed with a scanning electron microscope, the average thickness of the Al ₂ O ₃ layer on one main surface was 0.6 μm, and the average thickness of the Al ₂ O ₃ layer on the other main surface was It was 0.5 μm. When both surfaces of this sample were used for cutting evaluation under the following cutting conditions that required oxidation resistance, the cutting edge formed with the GM breaker had a cutting time of 14 minutes, and the cutting with the SM breaker formed. The cutting time was 10 minutes with the blade, and it was found that the cutting blade specifications on the GM breaker side showed better cutting performance under this cutting condition.
(Cutting conditions)
Work material: Inconel 718 Square tool shape: PNMU1205ANER-GM / SM (Kyocera Corporation insert)
Cutting speed: 40 m / min Feed rate: 0.25 mm / blade cutting: 2.0 mm (axial direction) × 10 mm (radial direction)
Other: Uses water-soluble cutting fluid

１切削工具
２基体
４ＴｉＮ層
５ＴｉＣＮ層
６中間層
７Ａｌ_２Ｏ_３層
８最表層
９被覆層 1 cutting tool 2 base 4 TiN layer 5 TiCN layer 6 intermediate layer 7 _Al 2 _{O 3} layer 8 outermost layer 9 covering layer

Claims

平均粒径０．９〜１．２μｍのＷＣ相を主体として、１０〜１５質量％のＣｏと、０．２〜０．６質量％のＣｒ_３Ｃ_２とを含有する超硬合金からなる基体の表面に、平均厚みが１〜３μｍのＴｉＣＮ層と、平均厚みが０．３〜０．７μｍのＡｌ_２Ｏ_３層と、が前記基体側から順に位置するとともに、前記Ａｌ _２Ｏ _３層の表面に、平均厚みが０．３〜０．７μｍのＴｉＣ _ｘＮ _ｙ層（０＜ｘ、０．５≦ｙ、ｘ＋ｙ＝１）からなる最表層が位置し、該最表層の表面において、切刃では粒状粒子からなり、すくい面では針状粒子からなる被覆工具。 A substrate made of a cemented carbide containing, as a main component, a WC phase having an average particle size of 0.9 to 1.2 μm and containing 10 to 15% by mass of Co and 0.2 to 0.6% by mass of Cr ₃ C ₂ on the surface of a TiCN layer having an average thickness of 1 to 3 [mu] m, average thickness and _{the Al} 2 _{O 3} layer of 0.3 to 0.7 [mu] m, with the you turn position from the base side, wherein _{the Al} 2 _{O 3} layer The outermost layer consisting of a TiC _x N _y layer (0 <x, 0.5 ≦ y, x + y = 1) having an average thickness of 0.3 to 0.7 μm is located on the surface of the outermost layer, A coated tool consisting of granular particles on the cutting edge and needle-like particles on the rake face .

平均粒径０．９〜１．２μｍのＷＣ相を主体として、１０〜１５質量％のＣｏと、０．２〜０．６質量％のＣｒ _３Ｃ _２とを含有する超硬合金からなる基体の表面に、平均厚みが１〜３μｍのＴｉＣＮ層と、平均厚みが０．３〜０．７μｍのＡｌ _２Ｏ _３層と、が前記基体側から順に位置するとともに、前記Ａｌ _２Ｏ _３層の表面に、平均厚みが０．３〜０．７μｍのＴｉＣ _ｘＮ _ｙ層（０＜ｘ、０．５≦ｙ、ｘ＋ｙ＝１）からなる最表層が位置し、該最表層は、すくい面において、基体側の炭素濃度が表面側の炭素濃度よりも高い被覆工具。 A substrate made of a cemented carbide containing , as a main component, a WC phase having an average particle size of 0.9 to 1.2 μm and containing 10 to 15% by mass of Co and 0.2 to 0.6% by mass of Cr ₃ C ₂ A TiCN layer having an average thickness of 1 to ₃ μm and an Al ₂ O ₃ layer having an average thickness of 0.3 to 0.7 μm are sequentially located on the surface of the substrate, and the Al ₂ O ₃ layer on the surface, the average thickness of _TiC x _{N y} layer of 0.3~0.7μm (0 <x, 0.5 ≦ y, x + y = 1) the outermost layer is located consisting of the outermost layer, the rake face , base side high have to be covered tool than the carbon concentration of the carbon concentration of the surface side of the.

平均粒径０．９〜１．２μｍのＷＣ相を主体として、１０〜１５質量％のＣｏと、０．２〜０．６質量％のＣｒ _３Ｃ _２とを含有する超硬合金からなる基体の表面に、平均厚みが１〜３μｍのＴｉＣＮ層と、平均厚みが０．３〜０．７μｍのＡｌ _２Ｏ _３層と、が前記基体側から順に位置するとともに、概略板状の両面使いの切削工具であって、一方の主面側の前記Ａｌ_２Ｏ_３層の厚みと他方の主面側の前記Ａｌ_２Ｏ_３層の厚みとが異なっている被覆工具。 A substrate made of a cemented carbide containing , as a main component, a WC phase having an average particle size of 0.9 to 1.2 μm and containing 10 to 15% by mass of Co and 0.2 to 0.6% by mass of Cr ₃ C ₂ A TiCN layer having an average thickness of 1 to ₃ μm and an Al ₂ O ₃ layer having an average thickness of 0.3 to 0.7 μm are sequentially disposed on the surface of the substrate, and the both sides of the substantially plate-like surface are used. a cutting tool, one main surface side the the Al ₂ O ₃ layer thickness and the other main surface side the the Al ₂ O ₃ layer of the covering tool and is that different thicknesses of the.

前記一方の主面側のブレーカ形状と前記他方の主面側のブレーカ形状とが異なっている請求項３記載の被覆工具。 The coated tool according to claim 3 , wherein the shape of the breaker on the one main surface side and the shape of the breaker on the other main surface side are different.

前記基体と前記ＴｉＣＮ層との間に、平均厚みが０．３〜０．７μｍのＴｉＮ層が積層されてなる請求項１乃至４のいずれか記載の被覆工具。 The coated tool according to any one of claims 1 to 4, wherein a TiN layer having an average thickness of 0.3 to 0.7 µm is laminated between the substrate and the TiCN layer.

前記ＴｉＣＮ層と前記Ａｌ_２Ｏ_３層との間に、平均厚みが０．０１〜０．１μｍのＴｉＣＯ、ＴｉＮＯおよびＴｉＣＮＯのうちのいずれかからなる中間層が積層されてなる請求項１乃至５のいずれか記載の被覆工具。 Between the _{the Al} 2 _{O 3} layer and the TiCN layer, the average thickness of 0.01 to 0.1 m TiCO, intermediate layer made of any one of TiNO and TiCNO is laminated claims 1 to 5 A coated tool according to any one of the above.