JP2019063900A

JP2019063900A - Surface-coated cutting tool having hard coating layer exerting excellent chipping resistance and wear resistance

Info

Publication number: JP2019063900A
Application number: JP2017189539A
Authority: JP
Inventors: 卓也石垣; Takuya Ishigaki; 翔龍岡; Sho Tatsuoka; 佐藤　賢一; Kenichi Sato; 佐藤　　賢一; 光亮柳澤; Mitsuaki Yanagisawa; 西田　真; Makoto Nishida; 西田　　真; 直誓今; Naochika Kon; 一千葉; Hajime Chiba
Original assignee: Mitsubishi Materials Corp
Current assignee: Mitsubishi Materials Corp
Priority date: 2017-09-29
Filing date: 2017-09-29
Publication date: 2019-04-25
Anticipated expiration: 2037-09-29
Also published as: JP6857299B2

Abstract

To provide a surface-coated cutting tool exerting excellent chipping resistance and wear resistance in high-speed intermittent cutting work for alloy steel or the like.SOLUTION: An objective surface-coated cutting tool has a hard coating layer including at least a TiAlCN layer on the surface of a tool base body. The TiAlCN layer satisfies 0.60≤X≤0.95 and 0≤Y≤0.005 (both X and Y are atomic ratios) in a composition formula: (TiAl)(CN). In the TiAlCN layer, there is a composition unevenness Δx represented by 0.03≤Δx≤0.20 in a crystal grain when carrying out mapping of Al content ratio x by an energy dispersion type X-ray analysis (EDS) with respect to an optional crystal grain having the NaCl type face-centered cubic structure using a transmission electron microscope and further, the crystal grain in which the average spot orientation difference (GAM) of the crystal grain represents less than 0.5 degree exists when carrying out mapping of crystal orientation by an electronic diffraction pattern with respect to the same place as above.SELECTED DRAWING: Figure 1

Description

本発明は、合金鋼等の高熱発生を伴うとともに、切刃に対して衝撃的な負荷が作用する高速断続切削加工で、硬質被覆層がすぐれた耐チッピング性、耐摩耗性を備えることにより、長期の使用に亘ってすぐれた切削性能を発揮する表面被覆切削工具（以下、被覆工具という）に関するものである。 The present invention is a high-speed interrupted cutting process in which an impact load acts on the cutting edge while generating high heat such as alloy steel, and the hard coating layer has excellent chipping resistance and wear resistance. The present invention relates to a surface-coated cutting tool (hereinafter referred to as a coated tool) that exhibits excellent cutting performance over long-term use.

従来、一般に、炭化タングステン（以下、ＷＣで示す）基超硬合金、炭窒化チタン（以下、ＴｉＣＮで示す）基サーメットあるいは立方晶窒化ホウ素（以下、ｃＢＮで示す）基超高圧焼結体で構成された工具基体（以下、これらを総称して工具基体という）の表面に、硬質被覆層として、Ｔｉ−Ａｌ系の複合窒化物層を物理蒸着法により被覆形成した被覆工具が知られており、これらは、すぐれた耐摩耗性を発揮することが知られている。
ただ、前記従来のＴｉ−Ａｌ系の複合窒化物層を被覆形成した被覆工具は、比較的耐摩耗性にすぐれるものの、高速断続切削条件で用いた場合にチッピング等の異常損耗を発生しやすいことから、硬質被覆層の改善についての種々の提案がなされている。 Conventionally, tungsten carbide (hereinafter referred to as WC) -based cemented carbide, titanium carbonitride (hereinafter referred to as TiCN) -based cermet or cubic boron nitride (hereinafter referred to as cBN) -based ultrahigh-pressure sintered body is generally used. There is known a coated tool in which a Ti—Al-based composite nitride layer is coated by physical vapor deposition as a hard coating layer on the surface of the tool base (hereinafter referred to collectively as tool base). These are known to exhibit excellent wear resistance.
However, although the coated tool on which the conventional Ti-Al composite nitride layer is formed is relatively excellent in wear resistance, it tends to generate abnormal wear such as chipping when used under high speed interrupted cutting conditions. Thus, various proposals have been made for improvement of the hard coating layer.

例えば、特許文献１には、基材と、その表面に形成された硬質被膜とを含む表面被覆部材であって、
前記硬質被膜は１または２以上の層により構成され、
前記層のうち少なくとも１層は、硬質粒子を含む層であり、
前記硬質粒子は、第１単位層と第２単位層とが交互に積層された多層構造を含み、
前記第１単位層は、周期表の４族元素、５族元素、６族元素およびＡｌからなる群より選ばれる１種以上の元素と、Ｂ、Ｃ、ＮおよびＯからなる群より選ばれる１種以上の元素とからなる第１化合物を含み、
前記第２単位層は、周期表の４族元素、５族元素、６族元素およびＡｌからなる群より選ばれる１種以上の元素と、Ｂ、Ｃ、ＮおよびＯからなる群より選ばれる１種以上の元素とからなる第２化合物を含む、表面被覆部材について提案され、この表面被覆部材によれば、耐摩耗性および耐溶着性などの諸特性が向上するため、安定化、長寿命化を図ることができるとされている。 For example, Patent Document 1 discloses a surface covering member including a substrate and a hard coating formed on the surface thereof,
The hard coating is composed of one or more layers,
At least one of the layers is a layer containing hard particles,
The hard particles include a multilayer structure in which first unit layers and second unit layers are alternately stacked,
The first unit layer is selected from the group consisting of B, C, N and O, and one or more elements selected from the group consisting of Group 4 elements, Group 5 elements, Group 6 elements and Al of the periodic table Containing a first compound consisting of a species or more of elements,
The second unit layer is selected from the group consisting of B, C, N and O, and one or more elements selected from the group consisting of Group 4 elements, Group 5 elements, Group 6 elements and Al of the periodic table It is proposed about the surface covering member which contains the 2nd compound which consists of an element or more elements, and according to this surface covering member, since various characteristics, such as abrasion resistance and welding resistance, improve, stabilization and long life improvement are carried out. Can be

また、特許文献２には、基体上にＣＶＤで形成された３〜２５μｍの耐摩耗コーティング層を有する工具において、耐摩耗性コーティング層は、少なくとも、Ｔｉ_１−ｘＡｌ_ｘＣ_ｙＮ_ｚで表した場合に、０．７０≦ｘ＜１、０≦ｙ＜０．２５および０．７５≦ｚ＜１.１５を満足し、１．５〜１７μｍの層厚を有するＴｉＡｌＣＮ層を備え、該層は、１５０ｎｍ未満のラメラ間隔のラメラ構造を有し、該ラメラ構造は、交互に異なったＴｉ量とＡｌ量を有するＴｉ_１−ｘＡｌ_ｘＣ_ｙＮ_ｚが周期的に形成されていることによって成るラメラ構造であり、さらに、同一結晶構造を有し、Ｔｉ_１−ｘＡｌ_ｘＣ_ｙＮ_ｚ層は少なくとも９０体積％以上が面心立方構造を有することが開示されている。
このような同一結晶構造からなるラメラ構造を有することで、面心立方構造と六方構造のラメラ構造に比べ、硬さが向上することにより、耐摩耗性が向上するため、長寿命化を図ることができるとされている。 Also, according to Patent Document 2, in a tool having a 3 to 25 μm abrasion resistant coating layer formed by CVD on a substrate, the abrasion resistant coating layer is at least represented by Ti _1−x Al _x C _y N _z And a TiAlCN layer having a layer thickness of 1.5 to 17 μm, satisfying 0.70 ≦ x <1, 0 ≦ y <0.25 and 0.75 ≦ z <1.15. Has a lamellar structure of lamellar spacing less than 150 nm, and the lamellar structure is formed by periodically forming Ti _1-x Al _x C _y N _z having alternately different amounts of Ti and Al. comprising a lamellar structure, further having the same crystal _{_{_{structure, Ti 1-x Al x C}}} y N z layer is at least 90 vol% or more is disclosed to have a face-centered cubic structure.
By having a lamellar structure having such an identical crystal structure, the hardness is improved as compared with the lamellar structure of a face-centered cubic structure and a hexagonal structure, and therefore, the wear resistance is improved, thereby achieving a long life. It is believed that

また、特許文献３、４、５、６、７には、ＴｉとＡｌの複合窒化物もしくは複合炭窒化物層、または、ＴｉとＡｌとＭｅ（但し、Ｍｅは、Ｓｉ、Ｚｒ、Ｂ、Ｖ、Ｃｒの中から選ばれる一種の元素）の複合窒化物もしくは複合炭窒化物層、または、ＣｒとＡｌの複合窒化物もしくは複合炭窒化物層で構成される硬質皮膜層について、結晶粒中のＮａＣｌ型の面心立方構造を有する結晶粒の結晶方位について、電子線後方散乱回折装置を用いて縦断面方向から解析される結晶粒個々の結晶粒内平均方位差（ＧＯＳ値）をある一定水準以上に導入する技術が開示されている。そして、この技術によれば（Ｔｉ_１−ＸＡｌ_Ｘ）（Ｃ_ＹＮ_１−Ｙ）層からなる硬質被覆層を合金鋼の高速断続切削等に用いた場合に、チッピング、欠損の発生が抑えられるとともに、長期の表面被覆工具の使用にわたって優れた耐摩耗性が発揮されるとされている。 In Patent Documents 3, 4, 5, 6, and 7, composite nitride or composite carbonitride layers of Ti and Al, or Ti, Al, and Me (where Me is Si, Zr, B, V, , A compound nitride or composite carbonitride layer of one kind of element selected from Cr, or a hard coating layer composed of a compound nitride or composite carbonitride layer of Cr and Al, With regard to the crystal orientation of crystal grains having a face-centered cubic structure of the NaCl type, a certain level of average intra-grain misorientation (GOS value) of individual crystal grains analyzed from the longitudinal cross-sectional direction using an electron beam backscattering diffractometer The techniques introduced above are disclosed. Then, according to this technology _(Ti _{_1-X} Al _X) hard coating layer consisting of (C _{Y N 1-Y)} layer when used in a high-speed intermittent cutting such as alloy steel, chipping, occurrence of defects is suppressed It is said that excellent wear resistance is exhibited over the long-term use of surface-coated tools.

特開２０１４−１２９５６２号公報JP, 2014-129562, A 国際公開第２０１５／１３５８０２号International Publication No. 2015/135802 特開２０１５−２１４０１５号公報JP, 2015-214015, A 特開２０１６−５８６３号公報JP, 2016-5863, A 特開２０１７−８０８８３号公報JP 2017-80883 A 特開２０１７−８０８８４号公報JP 2017-80884 A 特開２０１７−４７５２６号公報JP, 2017-47526, A

近年の切削加工における省力化および省エネ化の要求は強く、これに伴い、切削加工は一段と高速化、高効率化の傾向にあり、被覆工具には、より一層、耐チッピング性、耐欠損性、耐剥離性等の耐異常損傷性が求められるとともに、長期の使用に亘ってのすぐれた耐摩耗性が求められている。
しかし、前記特許文献１、２に記載されている被覆工具では、合金鋼等の高熱発生を伴うとともに、切刃に対して衝撃的な負荷が作用する高速断続切削加工において、耐チッピング、耐摩耗性が十分ではなく、満足できる切削性能を備えるとはいえない。
また、特許文献３〜７に記載された技術は、ＴｉＡｌ系あるいはＣｒＡｌ系の複合窒化物もしくは複合炭窒化物層の立方晶結晶構造を有する結晶粒の結晶粒内平均方位差（ＧＯＳ）に着目しているが、結晶粒内平均方位差（ＧＯＳ値）は対象のピクセルから遠方のピクセルとの方位差を含んだ評価であり、隣り合うピクセル同士の方位差については特段の考慮がなされていないため、結晶粒そのものの靱性を高めた皮膜とはとはいえない面がある。 In recent years, there is a strong demand for labor saving and energy saving in cutting processing, and along with this, cutting processing tends to be faster and more efficient, and the coated tools are more resistant to chipping, chipping, In addition to abnormal damage resistance such as peel resistance, excellent wear resistance over long-term use is also required.
However, the coated tools described in Patent Documents 1 and 2 are resistant to chipping and wear in high speed interrupted cutting in which an impactive load acts on the cutting edge while generating high heat such as alloy steel. The quality is not sufficient, and it can not be said to provide satisfactory cutting performance.
Further, the techniques described in Patent Documents 3 to 7 focus on the in-grain average misorientation (GOS) of crystal grains having a cubic crystal structure of a TiAl-based or CrAl-based composite nitride or composite carbonitride layer. However, the intra-grain average misorientation (GOS value) is an evaluation that includes the misorientation between the target pixel and the distant pixel, and no special consideration is given to the misorientation between adjacent pixels. Therefore, there is a surface which can not be said to be a film in which the toughness of the crystal grain itself is enhanced.

そこで、本発明は前記課題を解決し、合金鋼等の高速断続切削等に供した場合であっても、長期の使用に亘ってすぐれた耐チッピング性、耐摩耗性を発揮する被覆工具を提供することを目的とする。 Therefore, the present invention solves the above-mentioned problems, and provides a coated tool exhibiting excellent chipping resistance and wear resistance over long-term use even when subjected to high-speed interrupted cutting of alloy steel or the like. The purpose is to

本発明者らは、ＴｉとＡｌの複合窒化物または複合炭窒化物（以下、「ＴｉＡｌＣＮ」あるいは「（Ｔｉ_１−ｘＡｌ_ｘ）（Ｃ_ｙＮ_１−ｙ）」で示すことがある）層を少なくとも含む硬質被覆層を工具基体表面に設けた被覆工具の耐チッピング性、耐摩耗性の改善をはかるべく、鋭意研究を重ねた結果、次のような知見を得た。 The present inventors have found that composite nitride or composite carbonitride of Ti and Al (hereinafter, may be indicated by "TiAlCN" or _{_{_{"(Ti 1-x Al x)}}} (C y N 1-y) ") layer As a result of intensive studies aimed at improving the chipping resistance and the wear resistance of a coated tool provided on the surface of a tool base with a hard coating layer containing at least the following, the following findings were obtained.

即ち、ＴｉＡｌＣＮ層を構成するＴｉＡｌＣＮ結晶粒が、工具基体に垂直方向に柱状組織として形成されているような場合には、高靱性を有するものの、その反面、十分な硬さを備えるものではないため、耐チッピング性と耐摩耗性の両特性を相兼ね備えた被覆工具を得るためには、ＴｉＡｌＣＮ層の耐摩耗性を向上させることが望まれる。
そこで、本発明者らは、ＴｉＡｌＣＮ層を構成するＴｉＡｌＣＮ結晶粒の各結晶粒内における組成のむらと結晶方位差について鋭意研究したところ、ＴｉＡｌＣＮ層がＮａＣｌ型の面心立方構造を有する結晶粒を含有し、かつ、該ＮａＣｌ型の面心立方構造を有する結晶粒について結晶粒内のＡｌのＴｉとＡｌの合量に占める含有割合ｘ(以下、「Ａｌの含有割合ｘ」という) を測定した場合、結晶粒内には組成のむらΔｘが存在し、かつ、該Δｘが０．０３〜０．２０である場合には、結晶が歪むために硬さが高まることを見出した。
さらに、前記結晶粒内の組成のむらΔｘが０．０３〜０．２である結晶粒について、結晶粒内局所方位差平均（ＧＡＭ）を測定した場合、ＧＡＭが０．５度未満を示す結晶粒が存在する場合には、結晶粒内の組成のむらにより生じやすい結晶格子のミスマッチが抑制されるため、耐摩耗性が向上することを見出した。
したがって、ＴｉＡｌＣＮ層のＮａＣｌ型の面心立方構造を有する結晶粒について測定した前記Δｘが０．０３〜０．２０であり、かつ、前記ＧＡＭが０．５度未満である結晶粒が存在する場合には、ＴｉＡｌＣＮ層の硬さが向上するため、このようなＴｉＡｌＣＮ層を含む硬質被覆層を設けた被覆工具は、耐チッピング性と耐摩耗性の両特性を相兼ね備えることを見出したのである。 That is, when the TiAlCN crystal grains constituting the TiAlCN layer are formed as a columnar structure in the direction perpendicular to the tool base, they have high toughness, but on the other hand they do not have sufficient hardness. In order to obtain a coated tool having both chipping resistance and wear resistance, it is desirable to improve the wear resistance of the TiAlCN layer.
Therefore, the inventors of the present invention conducted intensive studies on composition unevenness and crystal orientation difference in each crystal grain of TiAlCN crystal grains constituting the TiAlCN layer, and the TiAlCN layer contains crystal grains having a face-centered cubic structure of NaCl type. And measuring the content ratio x of Al in the crystal particles to the total amount of Ti and Al (hereinafter referred to as “Al content ratio x”) for the crystal grain having a face-centered cubic structure of the NaCl type It has been found that when the unevenness of composition Δx exists in the crystal grain and the Δx is 0.03 to 0.20, the hardness is increased because the crystal is distorted.
Furthermore, when the local misorientation average (GAM) in the crystal grains is measured for the crystal grains whose composition unevenness Δx in the crystal grains is 0.03 to 0.2, the crystal grains having a GAM of less than 0.5 degrees It has been found that the wear resistance is improved because the existence of the crystal lattice mismatch which is likely to occur due to the composition unevenness in the crystal grains is suppressed.
Therefore, in the case where there is a crystal grain in which the Δx is 0.03 to 0.20 and the GAM is less than 0.5 degree measured for a crystal grain having a face-centered cubic structure of the NaCl type of the TiAlCN layer In order to improve the hardness of the TiAlCN layer, it has been found that a coated tool provided with a hard coating layer containing such a TiAlCN layer has both of the properties of chipping resistance and wear resistance.

本発明は、前記知見に基づいてなされたものであって、
「（１）炭化タングステン基超硬合金、炭窒化チタン基サーメットまたは立方晶窒化ホウ素基超高圧焼結体のいずれかで構成された工具基体の表面に、硬質被覆層を設けた表面被覆切削工具において、
（ａ）前記硬質被覆層は、平均層厚１〜２０μｍのＴｉとＡｌの複合窒化物または複合炭窒化物層を少なくとも含み、該複合窒化物または複合炭窒化物を、
組成式：（Ｔｉ_１−ｘＡｌ_ｘ）（Ｃ_ｙＮ_１−ｙ）
で表した場合、ＡｌのＴｉとＡｌの合量に占める平均含有割合ＸおよびＣのＣとＮの合量に占める平均含有割合Ｙ（但し、Ｘ、Ｙはいずれも原子比）は、それぞれ、０．６０≦Ｘ≦０．９５、０≦Ｙ≦０．００５を満足し、
（ｂ）前記複合窒化物または複合炭窒化物層について、透過型電子顕微鏡を用いて、複合窒化物または複合炭窒化物層内のＮａＣｌ型の面心立方構造を有する結晶粒に対して、エネルギー分散型Ｘ線分析（ＥＤＳ）により、結晶粒内の組成を５ｎｍ間隔で測定し、ＡｌのＴｉとＡｌの合量に占める含有割合ｘのマッピングを行った場合、結晶粒内に組成のむらΔｘがあり、該Δｘは０．０３〜０．２０である結晶粒が存在し、
（ｃ）前記エネルギー分散型Ｘ線分析（ＥＤＳ）測定を行った箇所と同じ個所について、電子回折パターンによる結晶方位マッピングを１０ｎｍ間隔で測定し、各々の測定点同士の結晶方位関係を解析し、測定した結晶粒の局所方位差平均を求めた場合、結晶粒の結晶粒内局所方位差平均（ＧＡＭ）が０．５度未満を示す結晶粒が存在し、
（ｄ）前記Δｘが０．０３〜０．２０であり、かつ、前記結晶粒内局所方位差平均（ＧＡＭ）が０．５度未満を示す結晶粒の存在割合は、前記エネルギー分散型Ｘ線分析（ＥＤＳ）測定を行った箇所に存在する前記ＮａＣｌ型の面心立方構造を有する結晶粒の総数の１０個数％以上であることを特徴とする表面被覆切削工具。
（２）前記工具基体と前記ＴｉとＡｌの複合窒化物または複合炭窒化物層の間に、Ｔｉの炭化物層、窒化物層、炭窒化物層、炭酸化物層および炭窒酸化物層のうちの１層または２層以上からなり、０．１〜２０μｍの合計平均層厚を有するＴｉ化合物層を含む下部層が存在することを特徴とする（１）に記載の表面被覆切削工具。
（３）前記複合窒化物または複合炭窒化物層の上部に、少なくとも酸化アルミニウム層を含む上部層が１〜２５μｍの合計平均層厚で存在することを特徴とする（１）または（２）に記載の表面被覆切削工具。」
に特徴を有するものである。
なお、本発明でいう“結晶粒内局所方位差平均”とは、後述するＧＡＭ（ＧｒａｉｎＡｖｅｒａｇｅＭｉｓｏｒｉｅｎｔａｔｉｏｎ）のことを意味する。
以下では、“結晶粒内局所方位差平均”を、単に“ＧＡＭ”と記す場合もある。 The present invention was made based on the above findings, and
“(1) A surface-coated cutting tool in which a hard coating layer is provided on the surface of a tool base made of either a tungsten carbide-based cemented carbide, a titanium carbonitride-based cermet, or a cubic boron nitride-based ultrahigh pressure sintered body In
(A) The hard coating layer at least includes a composite nitride or composite carbonitride layer of Ti and Al having an average layer thickness of 1 to 20 μm, and the composite nitride or composite carbonitride,
_{_{_{Formula: (Ti 1-x Al x}}} ) (C y N 1-y)
In this case, the average content ratio X of the total content of Ti and Al of Al and the average content ratio Y of the total content of C and N of C (where X and Y are both atomic ratios) are respectively 0.60 ≦ X ≦ 0.95, 0 ≦ Y ≦ 0.005,
(B) For the composite nitride or composite carbonitride layer, using a transmission electron microscope, the energy of the grains having a face-centered cubic structure of NaCl type in the composite nitride or composite carbonitride layer When the composition in crystal grains is measured at intervals of 5 nm by dispersive X-ray analysis (EDS), and mapping of the content ratio x in the total amount of Ti and Al in Al is performed, unevenness Δx of the composition in the crystal grains There are crystal grains in which Δx is 0.03 to 0.20.
(C) The crystal orientation mapping by the electron diffraction pattern is measured at intervals of 10 nm at the same place as the place where the energy dispersive X-ray analysis (EDS) measurement was performed, and the crystal orientation relationship between the respective measurement points is analyzed. When the local misorientation average of the measured crystal grains is determined, there are crystal grains whose local misorientation average (GAM) within the crystal grains is less than 0.5 degrees.
(D) The energy dispersive X-ray having the existence ratio of crystal grains in which the Δx is 0.03 to 0.20 and the intra-crystal grain local misorientation average (GAM) exhibits less than 0.5 degree A surface-coated cutting tool characterized in that it is 10% by number or more of the total number of crystal grains having a face-centered cubic structure of the NaCl type present in a place where analysis (EDS) measurement is performed.
(2) Among the carbide layer, nitride layer, carbonitride layer, carbooxide layer and carbonitride layer of Ti between the tool substrate and the composite nitride or carbonitride layer of Ti and Al The surface-coated cutting tool according to (1), wherein there is a lower layer comprising one or two or more layers and a Ti compound layer having a total average layer thickness of 0.1 to 20 μm.
(3) The upper layer containing at least an aluminum oxide layer is present on the composite nitride or composite carbonitride layer at a total average layer thickness of 1 to 25 μm (1) or (2) Surface-coated cutting tool as described. "
It is characterized by
In the present invention, the “local grain orientation difference average in crystal grains” means GAM (Grain Average Misorientation) described later.
In the following, “in-grain local misorientation average” may be simply referred to as “GAM”.

本発明について、以下に詳細に説明する。 The present invention is described in detail below.

ＴｉＡｌＣＮ層の平均層厚：
本発明の硬質被覆層は、組成式：（Ｔｉ_１−ｘＡｌ_ｘ）（Ｃ_ｙＮ_１−ｙ）で表されるＴｉＡｌＣＮ層を少なくとも含む。このＴｉＡｌＣＮ層は、硬さが高く、すぐれた耐摩耗性を有するが、特に平均層厚が１〜２０μｍのとき、その効果が際立って発揮される。これは、平均層厚が１μｍ未満では、層厚が薄いため長期の使用に亘っての耐摩耗性を十分確保することができず、一方、その平均層厚が２０μｍを越えると、ＴｉＡｌＣＮ層の結晶粒が粗大化し易くなり、チッピングを発生しやすくなるという理由による。
したがって、その平均層厚を１〜２０μｍと定めた。 Average layer thickness of TiAlCN layer:
Hard layer of the present invention, the composition _formula: containing at least TiAlCN layer represented by _{_{(Ti 1-x Al x)}} (C y N 1-y). The TiAlCN layer has high hardness and excellent abrasion resistance, but the effect is particularly exhibited when the average layer thickness is 1 to 20 μm. This is because if the average layer thickness is less than 1 μm, the wear resistance over a long period of use can not be sufficiently secured because the layer thickness is thin, while if the average layer thickness exceeds 20 μm, the TiAlCN layer The reason is that the crystal grains are easily coarsened and chipping tends to occur.
Therefore, the average layer thickness was determined to be 1 to 20 μm.

ＴｉＡｌＣＮ層の平均組成：
本発明におけるＴｉＡｌＣＮ層は、Ａｌの平均含有割合ＸおよびＣの平均含有割合Ｙ（但し、Ｘ、Ｙはいずれも原子比）が、それぞれ、０．６０≦Ｘ≦０．９５、０≦Ｙ≦０．００５を満足するように制御する。
その理由は、Ａｌの平均含有割合Ｘが０．６０未満であると、ＴｉＡｌＣＮ層は硬さに劣るため、合金鋼等の高速断続切削に供した場合には、耐摩耗性が十分でない。一方、Ａｌの平均含有割合Ｘが０．９５を超えると、相対的にＴｉの含有割合が減少するため、脆化を招き、耐チッピング性が低下する。
したがって、Ａｌの平均含有割合Ｘは、０．６０≦Ｘ≦０．９５と定めた。
また、ＴｉＡｌＣＮ層に含まれるＣの平均含有割合Ｙは、０≦Ｙ≦０．００５の範囲の微量であるとき、ＴｉＡｌＣＮ層と工具基体もしくは下部層との密着性が向上し、かつ、潤滑性が向上することによって切削時の衝撃を緩和し、結果としてＴｉＡｌＣＮ層の耐チッピング性、耐欠損性が向上する。一方、Ｃの平均含有割合Ｙが０≦Ｙ≦０．００５の範囲を逸脱すると、ＴｉＡｌＣＮ層の靭性が低下するため耐チッピング性、耐欠損性が逆に低下するため好ましくない。
したがって、Ｃの平均含有割合Ｙは、０≦Ｙ≦０．００５と定めた。 Average composition of TiAlCN layer:
In the TiAlCN layer in the present invention, the average content ratio of Al and the average content ratio Y of C (where X and Y are both atomic ratios) are respectively 0.60 ≦ X ≦ 0.95, 0 ≦ Y ≦ Control to satisfy 0.005.
The reason is that the TiAlCN layer is inferior in hardness when the average content ratio X of Al is less than 0.60, and therefore the wear resistance is not sufficient when subjected to high speed intermittent cutting of alloy steel or the like. On the other hand, if the average content ratio X of Al exceeds 0.95, the content ratio of Ti relatively decreases, which causes embrittlement and reduces the chipping resistance.
Therefore, the average content ratio X of Al was determined as 0.60 ≦ X ≦ 0.95.
Further, when the average content ratio Y of C contained in the TiAlCN layer is a slight amount in the range of 0 ≦ Y ≦ 0.005, the adhesion between the TiAlCN layer and the tool substrate or the lower layer is improved, and the lubricity is improved. Improves the impact during cutting, and as a result, the chipping resistance and fracture resistance of the TiAlCN layer are improved. On the other hand, when the average content ratio Y of C deviates from the range of 0 ≦ Y ≦ 0.005, the toughness of the TiAlCN layer is reduced, which is not preferable because the chipping resistance and the defect resistance are reduced.
Therefore, the average content ratio Y of C is defined as 0 ≦ Y ≦ 0.005.

ＴｉＡｌＣＮ層を構成するＮａＣｌ型の面心立方構造(以下、単に、「立方晶」ともいう)を有するＴｉＡｌＣＮ結晶粒内の組成のむらΔｘ：
本発明では、ＴｉＡｌＣＮ層の立方晶のＴｉＡｌＣＮ結晶粒内に、ＴｉとＡｌの含有割合の周期的組成変化(言い換えれば、前記組成式におけるＡｌの含有割合ｘの周期的変化)を存在させることによって、結晶粒に歪みを発生させ、硬さを向上する。しかし、前記組成式におけるＡｌの含有割合ｘの周期的変化の極大値の平均と極小値の平均の差、即ち、組成のむらΔｘ、が０．０３より小さいと前述した結晶粒の歪みが小さいため、十分な硬さの向上が見込めない。一方、ｘの極大値の平均と極小値の平均の差である組成のむらΔｘが０．２０を超えると結晶粒の歪みが大きくなり過ぎて格子欠陥が大きくなるため硬さが低下する。
そこで、立方晶のＴｉＡｌＣＮ結晶粒内に存在するＡｌの含有割合ｘの組成のむらΔｘを０．０３〜０．２０とする。好ましいΔｘは、０．０５〜０．１０である。
立方晶のＴｉＡｌＣＮ結晶粒内に存在する組成のむらΔｘは、ＴｉＡｌＣＮ層について、透過型電子顕微鏡を用いて、立方晶のＴｉＡｌＣＮ結晶粒に対して、エネルギー分散型Ｘ線分析（ＥＤＳ）により、結晶粒内の組成を５ｎｍ間隔で測定し、Ａｌの含有割合ｘのマッピングを行うことによって求めることができる。
図１に、結晶粒内に、ＴｉとＡｌの周期的組成変化が存在する立方晶のＴｉＡｌＣＮ結晶粒のＴＥＭ像の一例を示す。 Irregularity in composition Δx of TiAlCN crystal grains having a face-centered cubic structure of the NaCl type (hereinafter, also simply referred to as “cubic”) constituting the TiAlCN layer:
In the present invention, the periodic composition change of the content ratio of Ti and Al (in other words, the periodic change of the content ratio x of Al in the composition formula) is present in cubic TiAlCN crystal grains of the TiAlCN layer. , Generate distortion in crystal grains and improve hardness. However, if the difference between the average of the local maximum and the average of the local minimum of the periodic change ratio of Al in the composition formula, that is, the unevenness of composition Δx is smaller than 0.03, the above-mentioned distortion of the crystal grains is small. , I can not expect improvement in hardness enough. On the other hand, if the variation in composition Δx, which is the difference between the average of the maximum values of x and the average of the minimum values, exceeds 0.20, the strain of the crystal grains becomes too large and lattice defects increase, resulting in a decrease in hardness.
Therefore, the unevenness Δx of the composition of the content ratio x of Al present in the cubic TiAlCN crystal grains is set to 0.03 to 0.20. Preferred Δx is 0.05 to 0.10.
The unevenness of composition Δx present in cubic TiAlCN crystal grains is a grain size of the TiAlCN layer by energy dispersive X-ray analysis (EDS) with respect to cubic TiAlCN crystal grains using a transmission electron microscope. It can be determined by measuring the internal composition at intervals of 5 nm and performing mapping of the Al content ratio x.
FIG. 1 shows an example of a TEM image of cubic TiAlCN crystal grains in which periodic composition changes of Ti and Al exist in crystal grains.

ＴｉＡｌＣＮ層を構成する立方晶のＴｉＡｌＣＮ結晶粒の結晶粒内局所方位差平均（ＧＡＭ）：
本発明では、透過型電子顕微鏡を用いて、前記エネルギー分散型Ｘ線分析（ＥＤＳ）測定を行った箇所と同じ個所について、電子回折パターンによる結晶方位マッピングを１０ｎｍ間隔で測定し、各々の測定点同士の結晶方位関係を解析し、測定した結晶粒の結晶粒内局所方位差平均（ＧＡＭ）を求めた場合、ＧＡＭが０．５度未満を示す立方晶の結晶粒が存在することが必要である。
これは、Ａｌの含有割合ｘの組成のむらΔｘが０．０３〜０．２０である立方晶のＴｉＡｌＣＮ結晶粒において、該結晶粒の結晶粒内局所方位差平均（ＧＡＭ）が０．５度を超えると、組成のむらΔｘによる結晶格子のミスマッチが大きくなりすぎて、高熱発生を伴うとともに、切刃に対して衝撃的な負荷が作用する合金鋼等の高速断続切削加工における切削応力に耐えきれず、摩耗が進行しやすくなり、その結果、耐摩耗性が低下するからである。
そして、Δｘが０．０３〜０．２０であって、かつ、結晶粒内局所方位差平均（ＧＡＭ）が０．５度未満を示す結晶粒の存在割合が、エネルギー分散型Ｘ線分析（ＥＤＳ）測定を行った箇所に存在するＮａＣｌ型の面心立方構造を有する結晶粒の総数の１０個数％以上である場合に、高熱発生を伴うとともに、切刃に対して衝撃的な負荷が作用する合金鋼等の高速断続切削加工において、すぐれた耐チッピング性、耐摩耗性を発揮する。 Intra-grain local misorientation average (GAM) of cubic TiAlCN grains constituting the TiAlCN layer:
In the present invention, the crystal orientation mapping by the electron diffraction pattern is measured at intervals of 10 nm at the same place as the place where the energy dispersive X-ray analysis (EDS) measurement was performed using a transmission electron microscope. When analyzing the crystal orientation relationship between each other and determining the local intra-grain misorientation average (GAM) of the measured crystal grains, it is necessary that cubic crystal grains having a GAM of less than 0.5 degree be present is there.
This is because, in a cubic TiAlCN crystal grain having a composition nonuniformity Δx of the content ratio x of Al of 0.03 to 0.20, the local misorientation average (GAM) in the crystal grain of the crystal grain is 0.5 degree. If it exceeds, the mismatch of crystal lattice due to composition unevenness Δx becomes too large, and it is not possible to withstand the cutting stress in high speed interrupted cutting such as alloy steel with high heat generation and impact load acting on the cutting edge. The reason is that the wear tends to progress and as a result, the wear resistance is reduced.
And, the existence ratio of crystal grains having Δx of 0.03 to 0.20 and showing the intra-grain local misorientation average (GAM) of less than 0.5 degree is energy dispersive X-ray analysis (EDS) ) When the number is 10% or more of the total number of crystal grains having a face-centered cubic structure of NaCl type existing at the measured position, high heat generation is accompanied and an impactive load acts on the cutting edge Demonstrates excellent chipping resistance and wear resistance in high-speed interrupted cutting of alloy steels etc.

結晶粒内局所方位差平均（ＧＡＭ）は、前記エネルギー分散型Ｘ線分析（ＥＤＳ）測定を行った箇所と同じ個所のＴｉＡｌＣＮ層の表面研磨面について、表面に垂直な方向から、透過型電子顕微鏡を用いてナノサイズに収束された電子プローブを走査し、10ｎｍ間隔で電子回折パターンを取得して、結晶方位マッピングを得ることによって、結晶粒内局所方位差平均（ＧＡＭ）を求めることができる。 The local misorientation average (GAM) in the crystal grain is a transmission electron microscope from the direction perpendicular to the surface of the surface polished surface of the TiAlCN layer at the same place as the place where the energy dispersive X-ray analysis (EDS) measurement was performed. By scanning the electron probe converged to the nano size with using [1] to obtain electron diffraction patterns at intervals of 10 nm and obtaining crystal orientation mapping, it is possible to determine the intra-grain local misorientation average (GAM).

図２を用いて、より具体的に説明すれば、次のとおりである。
図２に示すように、隣接する測定点（以下、「ピクセル」ともいう）間で５度以上の方位差がある場合、そこを粒界と定義する。そして、粒界で囲まれた領域を１つの結晶粒と定義する。ただし、隣接するピクセル全てと５度以上の方位差がある単独に存在するピクセルは結晶粒とせず、２ピクセル以上が連結しているものを結晶粒として取り扱う。
そして、立方晶結晶粒内のあるピクセルと、これに隣接する他のピクセル間での方位差を計算し、これを結晶粒内局所方位差として求め、立方晶結晶粒内の全てのピクセルについて求めた結晶粒内局所方位差を平均化した値を、当該結晶粒における結晶粒内局所方位差平均ＧＡＭ（ＧｒａｉｎＡｖｅｒａｇｅＭｉｓｏｒｉｅｎｔａｔｉｏｎ）として定義する。
なお、ＧＡＭについては、例えば、文献「日本機械学会論文集(Ａ編) ７１巻７１２号（２００５−１２）論文Ｎｏ．０５−０３６７１７２２〜１７２８」に説明がなされている。
本発明でいう“結晶粒内局所方位差平均”とは、このＧＡＭを意味する。
なお、ＧＡＭを数式で表す場合、同一結晶粒内のあるピクセルとこれに隣接する他のピクセルの境界数をｍ、同一結晶粒内の隣接するピクセル間の境界におのおの付けた番号をｉ（ここで１≦ｉ≦ｍとなる）、境界ｉにおいて隣接するそれぞれのピクセルの結晶方位から求められる局所方位差をα_ｉとすると、

で表すことができる。
即ち、結晶粒内局所方位差平均（ＧＡＭ）は、結晶粒内の隣接するピクセル間での方位差(局所方位差)を求め、その値を平均化した数値であるといえる。 It will be as follows if it demonstrates more concretely using FIG.
As shown in FIG. 2, when there is a misorientation of 5 degrees or more between adjacent measurement points (hereinafter also referred to as "pixels"), these are defined as grain boundaries. Then, a region surrounded by grain boundaries is defined as one crystal grain. However, a single pixel which has a misorientation of 5 degrees or more with all adjacent pixels is not regarded as a crystal grain, but a pixel in which two or more pixels are connected is regarded as a crystal grain.
Then, the misorientation between one pixel in the cubic crystal grain and another pixel adjacent thereto is calculated, and this is determined as a local misorientation in the crystal grain, and is determined for all pixels in the cubic crystal grain. The value obtained by averaging the intra-grain local misorientation is defined as the intra-grain local misorientation average GAM (Grain Average Misorientation) of the crystal grain.
In addition, about GAM, description is made, for example, in the literature "The Japan Society of Mechanical Engineers, Proceedings of Part A, Volume 71, Issue 712 (2005-12), Paper Nos. 05-0367 1722-1728".
In the present invention, the “local grain orientation difference average in the grain” means this GAM.
When GAM is expressed by an equation, the boundary number of a pixel in the same crystal grain and the other pixels adjacent thereto is m, and a number assigned to the boundary between adjacent pixels in the same crystal grain is i (here Let 1 ≦ i ≦ m) and let α _i be the local misorientation determined from the crystal orientation of each pixel adjacent to the boundary i.

Can be represented by
That is, the local misorientation average (GAM) in the crystal grain can be said to be a numerical value obtained by determining the misorientation (local misorientation difference) between adjacent pixels in the crystal grain and averaging the values.

ＴｉＡｌＣＮ層の成膜法：
前記のような組成のむらΔｘおよび結晶粒内局所方位差平均（ＧＡＭ）を備えるＴｉＡｌＣＮ層は、例えば、工具基体表面において反応ガス組成を周期的に変化させる以下の化学蒸着法によって成膜することができる。
すなわち、化学蒸着反応装置へ、ＮＨ_３とＨ_２からなるガス群Ａと、ＴｉＣｌ_４、ＡｌＣｌ_３、Ｎ_２、Ｃ_２Ｈ_４、Ｈ_２からなるガス群Ｂをおのおの別々のガス供給管から反応装置内へ供給し、ガス群Ａとガス群Ｂの反応装置内への供給は、例えば、一定の周期の時間間隔で、その周期よりも短い時間だけガスが流れるように供給し、ガス群Ａとガス群Ｂのガス供給にはガス供給時間よりも短い時間の位相差が生じるようにして、工具基体表面における反応ガス組成を、（イ）ガス群Ａ、（ロ）ガス群Ａとガス群Ｂの混合ガス、（ハ）ガス群Ｂと時間的に変化させる。
そして、上記反応を例えば、
反応ガス組成（ガス群Ａおよびガス群Ｂを合わせた全体に対する容量％）：
ガス群Ａ：ＮＨ_３：０．５〜１．５％、Ｈ_２：３０〜５０％、
ガス群Ｂ：ＡｌＣｌ_３：０．２〜０．３％、ＴｉＣｌ_４：０．０７〜０．１０％、Ｎ_２：０．０〜４．０％、Ｃ_２Ｈ_４：０．０〜０．１％、Ｈ_２：残、
反応雰囲気圧力：４．５〜５．０ｋＰａ、
反応雰囲気温度：７００〜９００℃、
供給周期：１０〜３０秒、
１周期当たりのガス供給時間：０．５〜３．０秒、
ガス群Ａとガス群Ｂの位相差：０．４〜２．５秒
の条件で、所定時間、熱ＣＶＤ法を行うことによって、所定の組成のむらΔｘと結晶粒内局所方位差平均（ＧＡＭ）を備える本発明のＴｉＡｌＣＮ層を形成することができる。
また、成膜後にアニール処理を施すことによって、所定の組成のむらΔｘと結晶粒内局所方位差平均（ＧＡＭ）を制御することも可能である。
また、硬質被覆層の耐チッピング性、耐摩耗性の向上という観点からは、ＴｉＡｌＣＮ結晶粒は柱状組織であることが望ましいが、上記本発明の成膜法によれば、ＴｉＡｌＣＮ層を構成する立方晶のＴｉＡｌＣＮ結晶粒は柱状組織として形成されるため、耐チッピング性にすぐれたＴｉＡｌＣＮ層が得られる。 Deposition method of TiAlCN layer:
The TiAlCN layer provided with the unevenness of composition Δx and the intra-grain local misorientation average (GAM) as described above can be formed, for example, by the following chemical vapor deposition method in which the reaction gas composition is periodically changed on the tool substrate surface. it can.
That is, to the chemical vapor deposition reactor, the gas group A consisting of NH ₃ and H _2, and the gas group B consisting of TiCl ₄ , AlCl ₃ , N ₂ , C ₂ H ₄ , H ₂ are reacted from separate gas supply pipes. The gas group A and the gas group B are supplied into the reactor so that the gas flows for a time shorter than the cycle, for example, at a fixed cycle time interval. The reaction gas composition on the surface of the tool base is set such that (i) gas group A, (ii) gas group A, and gas group so that a phase difference of a time shorter than the gas supply time occurs in the gas supply of The mixture gas of (B) and the gas group B are temporally changed.
And, for example,
Reactive gas composition (% by volume based on the total of gas group A and gas group B combined):
Gas group A: NH ₃ : 0.5 to 1.5%, H ₂ : 30 to 50%,
Gas group B: AlCl ₃ : 0.2 to 0.3%, TiCl ₄ : 0.07 to 0.10%, N ₂ : 0.0 to 4.0%, C ₂ H ₄ : 0.0 to 0 %, H ₂ : Remaining,
Reaction atmosphere pressure: 4.5 to 5.0 kPa,
Reaction atmosphere temperature: 700-900 ° C.,
Supply cycle: 10-30 seconds,
Gas supply time per cycle: 0.5 to 3.0 seconds,
Phase difference between gas group A and gas group B: By performing thermal CVD method for a predetermined time under the condition of 0.4 to 2.5 seconds, unevenness Δx of predetermined composition and local misorientation average (GAM) in crystal grains The TiAlCN layer of the present invention can be formed.
In addition, by performing annealing after film formation, it is also possible to control the unevenness Δx of a predetermined composition and the local misorientation average (GAM) in crystal grains.
In addition, from the viewpoint of improving the chipping resistance and wear resistance of the hard coating layer, it is desirable that TiAlCN crystal grains have a columnar structure, but according to the film forming method of the present invention, the cubic of the TiAlCN layer is composed. Since the crystalline TiAlCN crystal grains are formed as a columnar structure, a TiAlCN layer excellent in chipping resistance can be obtained.

下部層および上部層：
また、本発明のＴｉＡｌＣＮ層は、それだけでも十分な効果を奏するが、Ｔｉの炭化物層、窒化物層、炭窒化物層、炭酸化物層および炭窒酸化物層のうちの１層または２層以上からなり、０．１〜２０μｍの合計平均層厚を有するＴｉ化合物層を含む下部層を設けた場合、あるいは、少なくとも酸化アルミニウム層を含む上部層が１〜２５μｍの合計平均層厚で設けられた場合には、これらの層が奏する効果と相俟って、一層すぐれた特性を発揮することができる。
Ｔｉの炭化物層、窒化物層、炭窒化物層、炭酸化物層および炭窒酸化物層のうちの１層または２層以上からなり、０．１〜２０μｍの合計平均層厚を有するＴｉ化合物層を含む下部層を設ける場合、下部層の合計平均層厚が０．１μｍ未満では、下部層の効果が十分に奏されず、一方、２０μｍを超えると結晶粒が粗大化し易くなり、チッピングを発生しやすくなる。また、酸化アルミニウム層を含む上部層の合計平均層厚が１μｍ未満では、上部層の効果が十分に奏されず、一方、２５μｍを超えると結晶粒が粗大化し易くなり、チッピングを発生しやすくなる。 Lower and upper layers:
In addition, the TiAlCN layer of the present invention is sufficiently effective by itself, but one or more of the carbide layer, the nitride layer, the carbonitride layer, the carbooxide layer and the carbonitride layer of Ti are effective. When a lower layer comprising a Ti compound layer having a total average layer thickness of 0.1 to 20 μm is provided, or an upper layer including at least an aluminum oxide layer is provided at a total average layer thickness of 1 to 25 μm In some cases, combined with the effects exerted by these layers, even better properties can be exhibited.
Ti compound layer comprising one or more layers of a carbide layer, a nitride layer, a carbonitride layer, a carbon oxide layer and a carbon oxynitride layer of Ti, and having a total average layer thickness of 0.1 to 20 μm If the total average layer thickness of the lower layer is less than 0.1 μm, the effect of the lower layer is not sufficiently exhibited, while if it exceeds 20 μm, the crystal grains are easily coarsened and chipping occurs. It becomes easy to do. In addition, if the total average layer thickness of the upper layer including the aluminum oxide layer is less than 1 μm, the effect of the upper layer is not sufficiently exhibited, while if it exceeds 25 μm, the crystal grains are easily coarsened and chipping tends to occur. .

本発明は、工具基体の表面に、硬質被覆層を設けた表面被覆切削工具において、硬質被覆層は、平均層厚１〜２０μｍのＴｉＡｌＣＮ層を少なくとも含み、
組成式：（Ｔｉ_１−ｘＡｌ_ｘ）（Ｃ_ｙＮ_１−ｙ）
で表した場合、Ａｌの平均含有割合ＸおよびＣの平均含有割合Ｙ（但し、Ｘ、Ｙはいずれも原子比）が、それぞれ、０．６０≦Ｘ≦０．９５、０≦Ｙ≦０．００５を満足し、ＴｉＡｌＣＮ層には立方晶結晶粒が存在し、該結晶粒の結晶粒内の組成を測定した場合、結晶粒内の組成のむらΔｘ０．０３〜０．２０が存在することによって、結晶が歪み硬さが向上し、さらに、Δｘが０．０３〜０．２０の結晶粒のうちで、結晶粒内局所方位差平均（ＧＡＭ）が０．５度未満のものが所定の個数％以上存在することによって、結晶格子のミスマッチが抑制され、その結果、ＴｉＡｌＣＮ層として耐摩耗性が向上する。
そのため、本発明被覆工具は、高熱発生を伴うとともに、切刃に対して衝撃的な負荷が作用する合金鋼等の高速断続切削加工に供した場合、すぐれた耐チッピング性とともにすぐれた耐摩耗性を発揮する。 The present invention provides a surface-coated cutting tool in which a hard coating layer is provided on the surface of a tool substrate, wherein the hard coating layer at least includes a TiAlCN layer having an average layer thickness of 1 to 20 μm,
_{_{_{Formula: (Ti 1-x Al x}}} ) (C y N 1-y)
In this case, the average content ratio Y of Al and the average content ratio Y of C (where X and Y are both atomic ratios) are respectively 0.60 ≦ X ≦ 0.95, 0 ≦ Y ≦ 0. 005 is satisfied, cubic crystal grains are present in the TiAlCN layer, and when the composition in the crystal grains of the crystal grains is measured, unevenness of the composition Δx 0.03 to 0.20 in the crystal grains is present, The strain hardness of the crystal is improved, and among the crystal grains having a Δx of 0.03 to 0.20, those having a local misorientation average (GAM) within the crystal grain of less than 0.5 degree have a predetermined number% Due to the above, the mismatch of the crystal lattice is suppressed, and as a result, the wear resistance of the TiAlCN layer is improved.
Therefore, the coated tool of the present invention has high heat generation and excellent wear resistance as well as excellent chipping resistance when subjected to high-speed interrupted cutting of alloy steel or the like which exerts an impactive load on the cutting edge. Demonstrate.

結晶粒内に、ＴｉとＡｌの周期的組成変化が存在する立方晶のＴｉＡｌＣＮ結晶粒のＴＥＭ像の一例を示す。An example of the TEM image of the cubic TiAlCN crystal grain in which the periodic composition change of Ti and Al exists in a crystal grain is shown. 本発明被覆工具のＴｉとＡｌの複合窒化物または複合炭窒化物層のＮａＣｌ型の面心立方構造(立方晶)を有する結晶粒の結晶粒内局所方位差平均（ＧＡＭ）の測定方法の概略説明図を示す。Outline of measurement method of local misorientation average (GAM) of grains having face-centered cubic structure (cubic crystal) of NaCl type of composite nitride of Ti and Al or composite carbonitride layer of the present invention coated tool or the present invention An explanatory view is shown.

次に、本発明の被覆工具を実施例により具体的に説明する。
なお、実施例としては、ＷＣ基超硬合金、ＴｉＣＮ基サーメットを工具基体とする被覆工具について述べるが、工具基体としてｃＢＮ基超高圧焼結体を用いた場合も同様である。 Next, the coated tool of the present invention will be specifically described by way of examples.
In addition, although the coated tool which makes a WC base cemented carbide and a TiCN base cermet a tool base is described as an example, it is the same as when a cBN base superhigh-pressure sintered compact is used as a tool base.

原料粉末として、いずれも１〜３μｍの平均粒径を有するＷＣ粉末、ＴｉＣ粉末、ＴａＣ粉末、ＮｂＣ粉末、Ｃｒ_３Ｃ_２粉末およびＣｏ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、さらにワックス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、９８ＭＰａの圧力で所定形状の圧粉体にプレス成形し、この圧粉体を５Ｐａの真空中、１３７０〜１４７０℃の範囲内の所定の温度に１時間保持の条件で真空焼結し、焼結後、ＩＳＯ規格ＳＥＥＮ１２０３ＡＦＳＮのインサート形状をもったＷＣ基超硬合金製の工具基体α〜γをそれぞれ製造した。 As raw material powders, WC powders, TiC powders, TaC powders, NbC powders, Cr ₃ C ₂ powders and Co powders each having an average particle diameter of 1 to 3 μm are prepared, and these raw material powders are compounded as shown in Table 1 Add to the composition, add a wax, mix in a ball mill in acetone for 24 hours, dry under reduced pressure, press-mold into a green compact of a predetermined shape at a pressure of 98 MPa, and press the green compact in a vacuum of 5 Pa 1370 Vacuum sintered under the condition of holding for 1 hour at a predetermined temperature within the range of 1470 ° C, and after sintering, manufacture tool base α to γ made of WC base cemented carbide with insert shape of ISO standard SEEN 1203 AFSN did.

また、原料粉末として、いずれも０．５〜２μｍの平均粒径を有するＴｉＣＮ（質量比でＴｉＣ／ＴｉＮ＝５０／５０）粉末、Ｍｏ_２Ｃ粉末、ＺｒＣ粉末、ＮｂＣ粉末、ＷＣ粉末、Ｃｏ粉末およびＮｉ粉末を用意し、これら原料粉末を、表２に示される配合組成に配合し、ボールミルで２４時間湿式混合し、乾燥した後、９８ＭＰａの圧力で圧粉体にプレス成形し、この圧粉体を１．３ｋＰａの窒素雰囲気中、温度：１５００℃に１時間保持の条件で焼結し、焼結後、ＩＳＯ規格ＳＥＥＮ１２０３ＡＦＳＮのインサート形状をもったＴｉＣＮ基サーメット製の工具基体δを作製した。 Also, as raw material powders, TiCN powder (TiC / TiN = 50/50 by mass ratio), Mo ₂ C powder, ZrC powder, NbC powder, WC powder, Co powder each having an average particle diameter of 0.5 to 2 μm. And Ni powder are prepared, these raw material powders are compounded into the composition shown in Table 2, wet mixed in a ball mill for 24 hours, dried, and then pressed into a green compact at a pressure of 98 MPa, this green compact The body was sintered in a nitrogen atmosphere of 1.3 kPa at a temperature of 1500 ° C. for 1 hour, and after sintering, a tool base δ made of a TiCN-based cermet having an insert shape of ISO standard SEEN 1203 AFSN was prepared.

つぎに、これらの工具基体α〜δの表面に、化学蒸着装置を用い、成膜反応を行った。
成膜反応は、次のとおりである。
表４、表５に示される形成条件Ａ〜Ｈ、すなわち、ＮＨ_３とＨ_２からなるガス群Ａと、ＴｉＣｌ_４、ＡｌＣｌ_３、Ｎ_２、Ｃ_２Ｈ_４、Ｈ_２からなるガス群Ｂ、およびおのおのガスの供給方法として、反応ガス組成（ガス群Ａおよびガス群Ｂを合わせた全体に対する容量％）を、ガス群ＡとしてＮＨ_３：０．５〜１．５％、Ｈ_２：３０〜５０％、ガス群ＢとしてＡｌＣｌ_３：０．２〜０．３％、ＴｉＣｌ_４：０．０７〜０．１０％、Ｎ_２：０．０〜４．０％、Ｃ_２Ｈ_４：０．０〜０．１％、Ｈ_２：残、反応雰囲気圧力：４．５〜５．０ｋＰａ、反応雰囲気温度：７００〜９００℃、供給周期１０〜３０秒、１周期当たりのガス供給時間０．５〜３．０秒、ガス群Ａとガス群Ｂの位相差０．４〜２．５秒として、所定時間、熱ＣＶＤ法を行った。 Next, a film forming reaction was performed on the surfaces of these tool bases α to δ using a chemical vapor deposition apparatus.
The film formation reaction is as follows.
The forming conditions A to H shown in Table 4 and Table 5, that is, the gas group A consisting of NH ₃ and H _2, and the gas group B consisting of TiCl ₄ , AlCl ₃ , N ₂ , C ₂ H ₄ , H ₂ , As a method of supplying each gas, the reaction gas composition (% by volume to the total of the gas group A and the gas group B combined), NH ₃ as the gas group A: 0.5 to 1.5%, H ₂ : 30 to 50%, AlCl ₃ as gas group B: 0.2 to 0.3%, TiCl ₄ : 0.07 to 0.10%, N ₂ : 0.0 to 4.0%, C ₂ H ₄ : 0. 0 to 0.1%, H ₂ : Remaining, Reaction atmosphere pressure: 4.5 to 5.0 kPa, Reaction atmosphere temperature: 700 to 900 ° C., Supply cycle 10 to 30 seconds, Gas supply time per one cycle 0.5 -3.0 seconds, the phase difference between gas group A and gas group B is 0.4 to 2.5 seconds, and heat is given for a predetermined time VD method was carried out.

ついで、形成条件Ｃ，Ｅ、Ｆに関しては表５に示される条件、すなわち、アニール雰囲気圧力４．５〜５．０ｋＰａ、アニール雰囲気温度：７００〜９００℃、アニール時間１〜３時間として、Ｈ_２ガス減圧雰囲気下にてアニール処理を行った。
成膜反応、アニール処理を行うことによって、表７に示される組成のむらΔｘおよびＧＡＭ（結晶粒内局所方位差平均）を有する立方晶結晶粒が表７に示される個数％存在し、表７に示される目標層厚を有するＴｉＡｌＣＮ層を形成することにより本発明被覆工具１〜１２を製造した。
なお、本発明被覆工具４〜１０については、表３に示される形成条件で、表６に示される下部層および／または表７に示される上部層を形成した。 Then, with respect to the forming conditions C, E, and F, the conditions shown in Table 5, that is, the annealing atmosphere pressure 4.5 to 5.0 kPa, the annealing atmosphere temperature: 700 to 900 ° C., and the annealing time 1 to 3 hours, H ₂ Annealing was performed in a gas reduced pressure atmosphere.
By performing the film forming reaction and annealing, cubic crystal grains having unevenness of composition Δx and GAM (local in-grain misorientation average) shown in Table 7 are present in the number% shown in Table 7, and Table 7 Inventive coated tools 1-12 were produced by forming a TiAlCN layer with the indicated target layer thickness.
In the coated tools 4 to 10 of the present invention, the lower layer shown in Table 6 and / or the upper layer shown in Table 7 were formed under the forming conditions shown in Table 3.

また、比較の目的で、工具基体α〜δの表面に、表３に示される条件での下部層の形成を行い（あるいは、行わず）、表４、表５に示される形成条件ａ〜ｈでの成膜反応を行い、表８に示される目標層厚（μｍ）を有し、少なくともＴｉＡｌＣＮ層を含む硬質被覆層を蒸着形成した。
なお、表５に示すように、形成条件ａ〜ｅでは、成膜反応時に工具基体表面における反応ガス組成が時間的に変化しない様にＴｉＡｌＣＮ層を形成することにより比較被覆工具１〜１２を製造した。
なお、本発明被覆工具４〜１０と同様に、比較被覆工具４〜１０については、表３に示される形成条件で、表６に示される下部層および／または表８に示される上部層を形成した。 Further, for the purpose of comparison, the lower layer is formed on the surfaces of the tool bases α to δ under the conditions shown in Table 3 (or not performed), and the forming conditions a to h shown in Tables 4 and 5 The film formation reaction was carried out, and a hard covering layer having a target layer thickness (μm) shown in Table 8 and including at least a TiAlCN layer was vapor deposited.
As shown in Table 5, under the forming conditions a to e, the comparative coated tools 1 to 12 are manufactured by forming the TiAlCN layer so that the reaction gas composition on the tool substrate surface does not temporally change during the film forming reaction. did.
As with the coated tools 4 to 10 of the present invention, for the comparative coated tools 4 to 10, the lower layer shown in Table 6 and / or the upper layer shown in Table 8 are formed under the forming conditions shown in Table 3. did.

また、本発明被覆工具１〜１２、比較被覆工具１〜１２の各構成層の工具基体に垂直な方向の断面を、走査型電子顕微鏡（倍率５０００倍）を用いて測定し、観察視野内の５点の層厚を測って平均して平均層厚を求めたところ、いずれも表７および表８に示される目標層厚と実質的に同じ平均層厚を示した。 In addition, the cross section in the direction perpendicular to the tool base of each component layer of the coated tools 1 to 12 of the present invention and the comparative coated tools 1 to 12 is measured using a scanning electron microscope (5000 × magnification), When the layer thicknesses at five points were measured and averaged to obtain an average layer thickness, they all showed substantially the same average layer thickness as the target layer thickness shown in Tables 7 and 8.

また、ＴｉＡｌＣＮ層のＡｌの平均含有割合Ｘについては、電子線マイクロアナライザ（Ｅｌｅｃｔｒｏｎ−Ｐｒｏｂｅ−Ｍｉｃｒｏ−Ａｎａｌｙｓｅｒ：ＥＰＭＡ）を用い、表面を研磨した試料において、電子線を試料表面側から照射し、得られた特性Ｘ線の解析結果の１０点平均からＡｌの平均含有割合Ｘを求めた。
Ｃの平均含有割合Ｙについては、二次イオン質量分析（Ｓｅｃｏｎｄａｒｙ−Ｉｏｎ−Ｍａｓｓ−Ｓｐｅｃｔｒｏｓｃｏｐｙ：ＳＩＭＳ）により求めた。イオンビームを試料表面側から７０μｍ×７０μｍの範囲に照射し、スパッタリング作用によって放出された成分について深さ方向の濃度測定を行った。Ｃの平均含有割合ＹはＴｉＡｌＣＮ層についての深さ方向の平均値を示す。
ただし、Ｃの含有割合には、意図的にガス原料としてＣを含むガスを用いなくても含まれる不可避的なＣの含有割合を除外している。具体的にはＣ_２Ｈ_４の供給量を０とした場合のＴｉＡｌＣＮ層に含まれるＣの含有割合（原子比）を不可避的なＣの含有割合として求め、Ｃ_２Ｈ_４を意図的に供給した場合に得られるＴｉＡｌＣＮ層に含まれるＣの含有割合（原子比）から前記不可避的なＣの含有割合を差し引いた値をＹとして求めた。 In addition, with regard to the average content ratio X of Al in the TiAlCN layer, in a sample whose surface is polished using an electron-probe-micro-analyzer (EPMA), an electron beam is irradiated from the sample surface side to obtain the sample. The average content ratio X of Al was determined from the 10-point average of the analysis results of the characteristic X-rays.
About the average content rate Y of C, it calculated | required by secondary ion mass spectrometry (Secondary-Ion-Mass-Spectroscopy: SIMS). The ion beam was irradiated from the sample surface side to a range of 70 μm × 70 μm, and concentration measurement in the depth direction was performed on the component released by the sputtering action. The average content ratio Y of C indicates the average value in the depth direction for the TiAlCN layer.
However, the content ratio of C excludes the inevitable content ratio of C which is contained even if the gas containing C is intentionally not used as the gas raw material. Specifically, the content ratio (atomic ratio) of C contained in the TiAlCN layer when the supply amount of C ₂ H ₄ is 0 is obtained as the inevitable content ratio of C, and C ₂ H ₄ is intentionally supplied A value obtained by subtracting the above-mentioned unavoidable C content ratio from the C content ratio (atomic ratio) contained in the TiAlCN layer obtained in the case of the above was obtained as Y.

さらに、ＴｉＡｌＣＮ層の表面に垂直な方向からその表面研磨面について、透過型電子顕微鏡を用いて電子プローブを走査し、ＴｉＡｌＣＮ層の立方晶結晶粒のうち任意の結晶粒１０個に対して、エネルギー分散型Ｘ線分析（ＥＤＳ）を用い、結晶粒内の組成を５ｎｍ間隔で測定し、Ａｌの含有割合ｘのマッピングを行い、結晶粒内に存在するＡｌの含有割合ｘの変化を測定し、Ａｌの含有割合ｘの周期的変化の極大値の平均と極小値の平均の差を組成のむらΔｘとして求め、前記マッピング図から、組成のむらΔｘが０．０３〜０．２０を示す結晶粒をカウントした。
表７および表８に、その結果を示す。
また、図１に、本発明被覆工具７の組成のむらΔｘが存在する立方晶のＴｉＡｌＣＮ結晶粒のＴＥＭ像の一例を示す。 Furthermore, the electron probe is scanned using a transmission electron microscope on the surface polished surface from the direction perpendicular to the surface of the TiAlCN layer, and energy is applied to 10 arbitrary crystal grains of the cubic crystal grains of the TiAlCN layer. The composition in the crystal grain is measured at intervals of 5 nm using dispersed X-ray analysis (EDS), mapping of the content ratio x of Al is performed, and the change in the content ratio x of Al present in the crystal particle is measured, The difference between the average of the local maximum values of the periodic change of the content ratio x of Al and the average of the local minimum values is determined as the composition unevenness Δx, and from the mapping chart, the crystal grains showing the composition unevenness Δx of 0.03 to 0.20 are counted did.
Tables 7 and 8 show the results.
Further, FIG. 1 shows an example of a TEM image of cubic TiAlCN crystal grains in which unevenness Δx of the composition of the coated tool 7 of the present invention exists.

さらに、ＴｉＡｌＣＮ層の表面に垂直な方向からその表面研磨面について、前記エネルギー分散型Ｘ線分析（ＥＤＳ）を用いて測定した箇所と同じ箇所について、透過型電子顕微鏡（ＴＥＭ）に付属する結晶方位解析装置を用いて、表面研磨面の法線方向に対して０．５〜１．０度に傾けた電子線をＰｒｅｃｅｓｓｉｏｎ（歳差運動）照射しながら、電子線を任意のビーム径及び間隔でスキャンし、連続的に電子回折パターンを取り込み、個々の測定点の結晶方位を解析した。なお、本測定に用いた電子回折パターンの取得条件は、加速電圧２００ｋＶ、カメラ長２０ｃｍ、ビームサイズ２．４ｎｍで、測定ステップは１０．０ｎｍである。
また、個々の測定点の電子回折パターンを、立方晶の任意の方位に対してあらかじめ計算した電子回折パターンと比較し、最も良くマッチした結晶方位をその測定点の結晶方位として採用した。
次に、ＴｉＡｌＮ層の縦断面の測定範囲において、前記測定範囲内の各測定点における結晶方位を測定するとともに、隣接する測定点における結晶方位との角度差を求め、該角度差が５度以上の場合には、隣接する測定点の間にＴｉＡｌＮ結晶粒の粒界が存在するとして粒界の位置を定め、そして、粒界によって囲まれた領域をＴｉＡｌＮ結晶粒であるとした。この時、結晶粒内のあるピクセルと、これに隣接する同一結晶粒内の他のピクセル間における結晶粒内局所方位差を求め、結晶粒内局所方位差が０度以上０．１度未満、０．１度以上０．２度未満、０．２度以上０．３度未満、０．３度以上０．４度未満、・・・と０〜１０度の範囲を０．１度ごとに区切って、マッピングした。そのマッピング図から、結晶粒内局所方位差平均（ＧＡＭ）が０．５度未満を示す結晶粒を特定し、その結晶粒をカウントした。
表７および表８に、その結果を示す。
また、Δｘが０．０３〜０．２０を示し、かつ、結晶粒内局所方位差平均（ＧＡＭ）が０．５度未満を示す結晶粒をカウントし、個数％を算出した。
表７および表８に、その結果を示す。 Furthermore, the crystal orientation attached to a transmission electron microscope (TEM) at the same place as that measured using energy dispersive X-ray analysis (EDS) on the surface polished surface from the direction perpendicular to the surface of the TiAlCN layer While irradiating an electron beam tilted by 0.5 to 1.0 degree with respect to the normal direction of the surface polishing surface using Pression (precession motion) using an analyzer, the electron beam can be applied at an arbitrary beam diameter and interval The scanning was performed, and electron diffraction patterns were continuously taken, and crystal orientations of individual measurement points were analyzed. The conditions for obtaining the electron diffraction pattern used in this measurement are an acceleration voltage of 200 kV, a camera length of 20 cm, a beam size of 2.4 nm, and a measurement step of 10.0 nm.
In addition, the electron diffraction pattern of each measurement point was compared with the electron diffraction pattern previously calculated for any orientation of cubic crystals, and the best matched crystal orientation was adopted as the crystal orientation of the measurement point.
Next, in the measurement range of the longitudinal section of the TiAlN layer, the crystal orientation at each measurement point in the measurement range is measured, and the angle difference from the crystal orientation at the adjacent measurement points is determined. In the case of {circumflex over (f)}, the grain boundaries were located on the assumption that grain boundaries of TiAlN crystal grains were present between adjacent measurement points, and the region surrounded by the grain boundaries was regarded as TiAlN crystal grains. At this time, the intra-grain local misorientation difference between one pixel in the crystal grain and another pixel in the same crystal grain adjacent thereto is determined, and the intra-grain local misorientation is 0 degrees or more and less than 0.1 degree. 0.1 degree or more and less than 0.2 degree, 0.2 degree or more and less than 0.3 degree, 0.3 degree or more and less than 0.4 degree, ... and 0 to 10 degree range every 0.1 degree Separated and mapped. From the mapping diagram, a crystal grain showing a local misorientation average (GAM) within the crystal grain of less than 0.5 degree was identified, and the crystal grains were counted.
Tables 7 and 8 show the results.
Moreover, the crystal grain which shows (DELTA) x 0.03-0.20 and shows the local orientation difference average (GAM) in less than 0.5 degree in a crystal grain was counted, and number% was computed.
Tables 7 and 8 show the results.

つぎに、前記各種の被覆工具をいずれもカッタ径１２５ｍｍの工具鋼製カッタ先端部に固定治具にてクランプした状態で、本発明被覆工具１〜１２、比較被覆工具１〜１２について、以下に示す、合金鋼の高速断続切削の一種である乾式高速正面フライス、センターカット切削加工試験を実施し、切刃の逃げ面摩耗幅を測定した。
工具基体：炭化タングステン基超硬合金、炭窒化チタン基サーメット、
切削試験：乾式高速正面フライス、センターカット切削加工、
被削材：ＪＩＳ・ＳＣＭ４４０幅１００ｍｍ、長さ４００ｍｍのブロック材、
回転速度：９９４ｍｉｎ^−１、
切削速度：３９０ｍ／ｍｉｎ、
切り込み：３．０ｍｍ、
一刃送り量：０．２５ｍｍ／刃、
切削時間：８分、
表９に、その結果を示す。 Next, in a state in which the above various coated tools are clamped by a fixing jig to a tool steel cutter tip having a cutter diameter of 125 mm, the coated tools according to the present invention 1 to 12 and comparative coated tools 1 to 12 will be described below. The dry-type high-speed face milling cutter, which is a type of high-speed interrupted cutting of alloy steel, and a center-cut cutting test are conducted to measure the flank wear width of the cutting edge.
Tool base: Tungsten carbide based cemented carbide, titanium carbonitride based cermet,
Cutting test: dry high-speed face milling, center cut cutting,
Work material: JIS · SCM 440 width 100 mm, block material 400 mm long,
Speed of rotation: 994 min ^-1 ,
Cutting speed: 390 m / min,
Notch: 3.0 mm,
Single blade feed amount: 0.25 mm / blade,
Cutting time: 8 minutes,
Table 9 shows the results.

原料粉末として、いずれも１〜３μｍの平均粒径を有するＷＣ粉末、ＴｉＣ粉末、ＺｒＣ粉末、ＴａＣ粉末、ＮｂＣ粉末、Ｃｒ₃Ｃ₂粉末、ＴｉＮ粉末およびＣｏ粉末を用意し、これら原料粉末を、表１０に示される配合組成に配合し、さらにワックス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、９８ＭＰａの圧力で所定形状の圧粉体にプレス成形し、この圧粉体を５Ｐａの真空中、１３７０〜１４７０℃の範囲内の所定の温度に１時間保持の条件で真空焼結し、焼結後、切刃部にＲ：０．０７ｍｍのホーニング加工を施すことによりＩＳＯ規格ＣＮＭＧ１２０４１２のインサート形状をもったＷＣ基超硬合金製の工具基体ε〜ηをそれぞれ製造した。 Prepare WC powder, TiC powder, ZrC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, TiN powder and Co powder all having an average particle diameter of 1 to 3 μm as raw material powders, Add the wax to the formulation shown in Table 10, add wax, ball mill mix in acetone for 24 hours, dry under reduced pressure, press-form into a green compact of a specified shape with a pressure of 98 MPa, and press this green compact Vacuum sintering under the conditions of 1370 to 1470 ° C. for 1 hour in a vacuum of 5 Pa, and after sintering, apply honing of R: 0.07 mm to the cutting edge to achieve ISO standard Tool substrates ε to 製 made of WC-based cemented carbide with an insert shape of CNMG 120 412 were produced respectively.

また、原料粉末として、いずれも０．５〜２μｍの平均粒径を有するＴｉＣＮ（質量比でＴｉＣ／ＴｉＮ＝５０／５０）粉末、ＮｂＣ粉末、ＷＣ粉末、Ｃｏ粉末、およびＮｉ粉末を用意し、これら原料粉末を、表１１に示される配合組成に配合し、ボールミルで２４時間湿式混合し、乾燥した後、９８ＭＰａの圧力で圧粉体にプレス成形し、この圧粉体を１．３ｋＰａの窒素雰囲気中、温度：１５００℃に１時間保持の条件で焼結し、焼結後、切刃部分にＲ：０．０９ｍｍのホーニング加工を施すことによりＩＳＯ規格・ＣＮＭＧ１２０４１２のインサート形状をもったＴｉＣＮ基サーメット製の工具基体θを形成した。 In addition, as raw material powders, TiCN powder (TiC / TiN = 50/50 by mass ratio), NbC powder, WC powder, Co powder, and Ni powder each having an average particle diameter of 0.5 to 2 μm are prepared, These raw material powders are compounded into the composition shown in Table 11, wet mixed in a ball mill for 24 hours, dried, and then pressed into a green compact at a pressure of 98 MPa, and this green compact is subjected to nitrogen of 1.3 kPa Sintered in an atmosphere at a temperature of 1500 ° C. for 1 hour, and after sintering, apply a honing process of R: 0.09 mm to the cutting edge portion to obtain a TiCN group having an insert shape of ISO standard / CNMG 120 412. A tool base θ made of cermet was formed.

つぎに、これらの工具基体ε〜ηおよび工具基体θの表面に、化学蒸着装置を用い、実施例１と同様の方法により表３に示される条件での下部層の形成、表４、表５に示される条件で成膜反応、実施例１と同じ条件でのアニール処理を行うことにより、少なくともＴｉＡｌＣＮ層を含む硬質被覆層を目標層厚で蒸着形成することにより、表１３に示される本発明被覆工具１３〜２４を製造した。
なお、本発明被覆工具１６〜２０については、表３に示される形成条件で、表１２に示される下部層および／または表１３に示される上部層を形成した。 Next, formation of the lower layer under the conditions shown in Table 3 in the same manner as in Example 1 using a chemical vapor deposition apparatus on the surfaces of these tool substrates ε to および and tool substrate θ, Table 4, Table 5 The film forming reaction is performed under the conditions shown in FIG. 1 and the annealing treatment under the same conditions as in Example 1 is carried out to form a hard covering layer including at least a TiAlCN layer by vapor deposition with a target layer thickness. Coated tools 13 to 24 were manufactured.
With respect to the coated tools 16 to 20 of the present invention, the lower layer shown in Table 12 and / or the upper layer shown in Table 13 were formed under the forming conditions shown in Table 3.

また、比較の目的で、同じく工具基体ε〜ηおよび工具基体θの表面に、通常の化学蒸着装置を用い、表３に示される条件での下部層の形成、表４、表５に示される条件での成膜反応を行うことにより、表１４に示される比較被覆工具１３〜２４を製造した。
なお、本発明被覆工具１６〜２０と同様に、比較被覆工具１６〜２０については、表３に示される形成条件で、表１２に示される下部層および／または表１４に示される上部層を形成した。 Also, for the purpose of comparison, the formation of the lower layer under the conditions shown in Table 3 on the surface of the tool base ε to 工具 and the tool base θ similarly using the conventional chemical vapor deposition apparatus, as shown in Tables 4 and 5 By performing the film forming reaction under the conditions, comparative coated tools 13 to 24 shown in Table 14 were manufactured.
In the same manner as the coated tools 16 to 20 of the present invention, for the comparative coated tools 16 to 20, the lower layer shown in Table 12 and / or the upper layer shown in Table 14 are formed under the forming conditions shown in Table 3. did.

本発明被覆工具１３〜２４、比較被覆工具１３〜２４の各構成層の断面を、走査電子顕微鏡（倍率５０００倍）を用いて測定し、観察視野内の５点の層厚を測って平均して平均層厚を求めたところ、いずれも表１３および表１４に示される目標層厚と実質的に同じ平均層厚を示した。
また、実施例１と同様に、本発明被覆工具１３〜２４、比較被覆工具１３〜２４の立方晶構造のＴｉＡｌＣＮ結晶粒のうち任意の結晶粒１０個のうち、組成のむらΔｘが０．０３〜０．２０である結晶粒をカウントした。
また、実施例１と同様に、立方晶構造のＴｉＡｌＣＮ結晶粒について、結晶粒内局所方位差平均（ＧＡＭ）が０．５度未満である結晶粒をカウントした。
さらに、実施例１と同様に、Δｘが０．０３〜０．２０を示し、かつ、結晶粒内局所方位差平均（ＧＡＭ）が０．５度未満を示す結晶粒をカウントし、個数％を算出した。
表１３、表１４に、測定結果を示す。 The cross-sections of the respective constituent layers of the coated tools 13 to 24 of the present invention and the comparative coated tools 13 to 24 are measured using a scanning electron microscope (5000 × magnification), and the layer thicknesses of five points in the observation field are measured and averaged. The average layer thickness was determined, and both showed substantially the same average layer thickness as the target layer thickness shown in Tables 13 and 14.
Further, as in the first embodiment, the unevenness of composition Δx is 0.03 or less among 10 arbitrary crystal grains among TiAlCN crystal grains of the cubic crystal structure of the coated tools according to the present invention 13-24 and comparative coated tools 13-24. The crystal grain which is 0.20 was counted.
Further, in the same manner as in Example 1, for TiAlCN crystal grains having a cubic crystal structure, crystal grains having a local misorientation average (GAM) within the crystal grains of less than 0.5 degree were counted.
Furthermore, as in Example 1, Δx is 0.03 to 0.20, and the intra-grain local misorientation average (GAM) is less than 0.5 degrees. Calculated.
Tables 13 and 14 show the measurement results.

つぎに、前記各種の被覆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、本発明被覆工具１３〜２４、比較被覆工具１３〜２４について、以下に示す、炭素鋼の乾式高速断続切削試験、鋳鉄の湿式高速断続切削試験を実施し、いずれも切刃の逃げ面摩耗幅を測定した。
切削条件１：
被削材：ＪＩＳ・Ｓ４５Ｃの長さ方向等間隔４本縦溝入り丸棒、
切削速度：３９０ｍ／ｍｉｎ、
切り込み：１．５ｍｍ、
送り：０．３ｍｍ／ｒｅｖ、
切削時間：５分、
（通常の切削速度は、２２０ｍ／ｍｉｎ）、
切削条件２：
被削材：ＪＩＳ・ＦＣＤ７００の長さ方向等間隔４本縦溝入り丸棒、
切削速度：３７０ｍ／ｍｉｎ、
切り込み：２．０ｍｍ、
送り：０．１５ｍｍ／ｒｅｖ、
切削時間：５分、
（通常の切削速度は、２００ｍ／ｍｉｎ）、
表１５に、前記切削試験の結果を示す。 Next, in a state in which the various coated tools are screwed to the tip of the tool steel tool with a fixing jig, the coated tools 13 to 24 of the present invention and the comparative coated tools 13 to 24 are shown below, A dry high speed intermittent cutting test of carbon steel and a wet high speed intermittent cutting test of cast iron were conducted, and the flank wear width of the cutting edge was measured in each case.
Cutting condition 1:
Work material: JIS · S45C in the longitudinal direction equally spaced four vertical grooved round bar,
Cutting speed: 390 m / min,
Notch: 1.5 mm,
Feeding: 0.3 mm / rev,
Cutting time: 5 minutes,
(Normal cutting speed is 220m / min),
Cutting condition 2:
Work material: JIS · FCD 700 in the longitudinal direction equally spaced four vertical grooved round bar,
Cutting speed: 370 m / min,
Notch: 2.0 mm,
Feeding: 0.15 mm / rev,
Cutting time: 5 minutes,
(Normal cutting speed is 200m / min),
Table 15 shows the results of the cutting test.

表９および表１５に示される結果から、本発明の被覆工具は、ＡｌＴｉＣＮ層の立方晶結晶粒内において、所定の組成のむらΔｘが０．０３〜０．２あり、かつ、結晶粒内局所方位差平均（ＧＡＭ）が０．５度未満である立方晶結晶粒が存在することから、結晶粒が歪み硬さが向上し、一方、組成むらによる結晶格子のミスマッチが小さくなるため、耐チッピン性とともに耐摩耗性が向上し、その結果、高熱発生を伴い、かつ、切れ刃に断続的・衝撃的高負荷が作用する高速断続切削加工に用いた場合でも、長期の使用に亘ってすぐれた切削性能を発揮する。 From the results shown in Tables 9 and 15, in the coated crystal tool of the present invention, in the cubic crystal grains of the AlTiCN layer, the unevenness Δx of the predetermined composition is 0.03 to 0.2, and the local orientation in the grains The presence of cubic crystal grains having a difference average (GAM) of less than 0.5 degrees improves the strain hardness of the crystal grains, while the mismatch of the crystal lattice due to compositional unevenness decreases, so that chipping resistance is improved. At the same time, wear resistance is improved, and as a result, even when used for high-speed interrupted cutting with high heat generation and intermittent high impact acting on the cutting edge, excellent cutting over long-term use Demonstrate performance.

これに対して、ＡｌＴｉＣＮ層を構成する立方晶結晶粒内において、所定の組成のむらΔｘが存在していない比較被覆工具、あるいは、所定の結晶粒内局所方位差平均（ＧＡＭ）が存在していない比較被覆工具については、高熱発生を伴い、しかも、切れ刃に断続的・衝撃的高負荷が作用する高速断続切削加工に用いた場合、チッピング等の異常損傷の発生により、あるいは、摩耗進行の促進により、短時間で寿命に至ることが明らかである。 On the other hand, in the cubic crystal grains constituting the AlTiCN layer, a comparative coated tool in which the unevenness Δx of the predetermined composition does not exist, or a predetermined local misorientation average (GAM) in the crystal grains does not exist. Comparative coated tools are used for high speed intermittent cutting with high heat generation and high load intermittently acting on the cutting edge, or by the occurrence of abnormal damage such as chipping, or promoting the progress of wear. It is clear that the life is reached in a short time.

前述のように、本発明の被覆工具は、合金鋼の高速断続切削加工ばかりでなく、各種の被削材の被覆工具として用いることができ、しかも、長期の使用に亘ってすぐれた耐チッピング性、耐摩耗性を発揮するものであるから、切削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 mentioned above, the coated tool of the present invention can be used not only for high speed interrupted cutting of alloy steel but also as a coated tool for various work materials, and also has excellent chipping resistance over long-term use. Since the wear resistance is exhibited, it is possible to sufficiently meet the requirements for high performance of the cutting device, labor saving and energy saving of the cutting, and cost reduction.

Claims

In a surface-coated cutting tool in which a hard coating layer is provided on the surface of a tool base made of either a tungsten carbide base cemented carbide, a titanium carbonitride base cermet or a cubic boron nitride base ultrahigh pressure sintered body,
(A) The hard coating layer at least includes a composite nitride or composite carbonitride layer of Ti and Al having an average layer thickness of 1 to 20 μm, and the composite nitride or composite carbonitride,
_{_{_{Formula: (Ti 1-x Al x}}} ) (C y N 1-y)
In this case, the average content ratio X of the total content of Ti and Al of Al and the average content ratio Y of the total content of C and N of C (where X and Y are both atomic ratios) are respectively 0.60 ≦ X ≦ 0.95, 0 ≦ Y ≦ 0.005,
(B) For the composite nitride or composite carbonitride layer, using transmission electron microscopy, individual grains having a face-centered cubic structure of NaCl type in the composite nitride or composite carbonitride layer When the composition in the crystal grain is measured at intervals of 5 nm by energy dispersive X-ray analysis (EDS) and mapping of the content ratio x in the total amount of Ti and Al of Al is performed, unevenness of the composition in the crystal grain There are grains having Δx, which is 0.03 to 0.20,
(C) The crystal orientation mapping by the electron diffraction pattern is measured at intervals of 10 nm at the same place as the place where the energy dispersive X-ray analysis (EDS) measurement was performed, and the crystal orientation relationship between the respective measurement points is analyzed. When the local misorientation average of the measured crystal grains is determined, there are crystal grains whose local misorientation average (GAM) within the crystal grains is less than 0.5 degrees.
(D) The energy dispersive X-ray having the existence ratio of crystal grains in which the Δx is 0.03 to 0.20 and the intra-crystal grain local misorientation average (GAM) exhibits less than 0.5 degree A surface-coated cutting tool characterized in that it is 10% by number or more of the total number of crystal grains having a face-centered cubic structure of the NaCl type present in a place where analysis (EDS) measurement is performed.

One of a carbide layer, a nitride layer, a carbonitride layer, a carbonate layer and a carbonitride layer of Ti between the tool substrate and the composite nitride or composite carbonitride layer of Ti and Al The surface-coated cutting tool according to claim 1, wherein a lower layer comprising a Ti compound layer comprising two or more layers and having a total average layer thickness of 0.1 to 20 μm is present.

The surface-coated cutting according to claim 1 or 2, wherein an upper layer including at least an aluminum oxide layer is present on the composite nitride or composite carbonitride layer in a total average layer thickness of 1 to 25 μm. tool.