JP6931458B2 - Surface coating cutting tool with excellent wear resistance and chipping resistance with a hard coating layer - Google Patents
Surface coating cutting tool with excellent wear resistance and chipping resistance with a hard coating layer Download PDFInfo
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- 239000011247 coating layer Substances 0.000 title claims description 62
- 238000005520 cutting process Methods 0.000 title claims description 34
- 239000011248 coating agent Substances 0.000 title claims description 17
- 238000000576 coating method Methods 0.000 title claims description 17
- 239000010410 layer Substances 0.000 claims description 198
- 239000013078 crystal Substances 0.000 claims description 61
- 239000000758 substrate Substances 0.000 claims description 30
- 239000000203 mixture Substances 0.000 claims description 29
- 239000010936 titanium Substances 0.000 claims description 13
- 239000011195 cermet Substances 0.000 claims description 5
- UONOETXJSWQNOL-UHFFFAOYSA-N tungsten carbide Chemical compound [W+]#[C-] UONOETXJSWQNOL-UHFFFAOYSA-N 0.000 claims description 5
- 229910052582 BN Inorganic materials 0.000 claims description 4
- PZNSFCLAULLKQX-UHFFFAOYSA-N Boron nitride Chemical compound N#B PZNSFCLAULLKQX-UHFFFAOYSA-N 0.000 claims description 4
- NRTOMJZYCJJWKI-UHFFFAOYSA-N Titanium nitride Chemical compound [Ti]#N NRTOMJZYCJJWKI-UHFFFAOYSA-N 0.000 claims description 2
- 239000004094 surface-active agent Substances 0.000 claims description 2
- 238000000034 method Methods 0.000 description 11
- 229910045601 alloy Inorganic materials 0.000 description 10
- 239000000956 alloy Substances 0.000 description 10
- 230000000694 effects Effects 0.000 description 10
- 239000000843 powder Substances 0.000 description 9
- 229910018575 Al—Ti Inorganic materials 0.000 description 8
- 229910000851 Alloy steel Inorganic materials 0.000 description 7
- 238000005299 abrasion Methods 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 7
- 238000007733 ion plating Methods 0.000 description 6
- 230000007547 defect Effects 0.000 description 5
- 230000003647 oxidation Effects 0.000 description 5
- 238000007254 oxidation reaction Methods 0.000 description 5
- 238000005240 physical vapour deposition Methods 0.000 description 5
- 238000010030 laminating Methods 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 3
- 238000010891 electric arc Methods 0.000 description 3
- 238000013507 mapping Methods 0.000 description 3
- 229920006395 saturated elastomer Polymers 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 229910052719 titanium Inorganic materials 0.000 description 3
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- 229910017150 AlTi Inorganic materials 0.000 description 2
- 229910004349 Ti-Al Inorganic materials 0.000 description 2
- 229910004692 Ti—Al Inorganic materials 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000003801 milling Methods 0.000 description 2
- 150000004767 nitrides Chemical class 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 230000000007 visual effect Effects 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- 229910001069 Ti alloy Inorganic materials 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000013467 fragmentation Methods 0.000 description 1
- 238000006062 fragmentation reaction Methods 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
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Description
本発明は、合金鋼等の高速切削において、耐摩耗性と耐熱性を両立し、さらに、被覆層の耐チッピング性を発揮し、長期の使用にわたりすぐれた切削性能を有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 surface-coated cutting tool that achieves both wear resistance and heat resistance in high-speed cutting of alloy steel, etc., exhibits chipping resistance of the coating layer, and has excellent cutting performance over a long period of use (hereinafter referred to as , Called a covering tool).
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。
しかしながら、合金鋼の高速切削においては、耐摩耗性と耐熱性の両立が求められるため、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では、硬質被覆層の改善について種々の提案がなされている。
Conventionally, generally, a tungsten carbide (hereinafter referred to as WC) -based cemented carbide, a titanium carbonitride (hereinafter referred to as TiCN) -based cermet or a cubic boron nitride (hereinafter referred to as cBN) -based ultrahigh-pressure sintered body has been used. A coated tool in which a Ti—Al-based composite nitride layer is coated and formed as a hard coating layer on the surface of the constructed tool substrate (hereinafter, these are collectively referred to as a tool substrate) by a physical vapor deposition method is known. , These are known to exhibit excellent wear resistance.
However, in high-speed cutting of alloy steel, both wear resistance and heat resistance are required. Therefore, in the conventional coating tool coated with the Ti—Al-based composite nitride layer, various improvements in the hard coating layer are required. Has been proposed.
例えば、特許文献１では、炭化タングステン基超硬合金などで構成された工具基体の表面に、組成式：（Ｔｉ１−ｘＡｌｘ）Ｎ（ただし、原子比で、０＜ｘ＜０．６５）で示され、ｆｃｃ型結晶構造を有する低Ａｌで高硬度のＡｌＴｉＮ層と、組成式：（Ｔｉ１−ｙＡｌｙ）Ｎ（ただし、原子比で、０．６５≦ｙ＜１）で示され、ｈｃｐ型結晶構造を有する高Ａｌで耐酸化性に優れたＡｌＴｉＮ層とを、交互に積層化し、高硬度に基づく耐摩耗性と高い耐酸化性とを両立した被覆層を有する被覆工具が提案されている。 For example, in Patent Document 1, the composition formula: (Ti 1-x Al x ) N (however, in terms of atomic ratio, 0 <x <0.65) is formed on the surface of a tool substrate made of a tungsten carbide-based cemented carbide or the like. ) is indicated by, and AlTiN layer of high hardness with low Al having an fcc crystal structure, composition formula: (Ti 1-y Al y ) N ( where atomic ratio, shown in 0.65 ≦ y <1) A coating tool having a coating layer that has both high hardness-based abrasion resistance and high oxidation resistance is obtained by alternately laminating AlTiN layers having a high Al and excellent oxidation resistance having an hcp type crystal structure. Proposed.
また、特許文献２では、工具基体の表面に、耐火被覆層を設けた被覆工具において、前記耐火被覆層は、工具基体の表面側から、ＴｉＮである場合を含め、低Ａｌ濃度のＡｌＴｉＮなどの立方晶型の結晶構造を有する層と、該層に隣接し、（Ｔｉ１−ｘＡｌｘ）Ｎ（原子比で、ｘ＞０．５）にて示さる層とを組として、ＰＶＤ法を用いて複数組を成膜した積層構造を有し、耐火被覆層全体では、０．５〜１５ｗｔ％の六方晶構造相を有する被覆工具が記載されており、かかる被覆工具において、一定レベル以上の硬度および耐酸化性を有する被覆層を形成することにより、工具寿命の長期化を図ることが提案されている。 Further, in Patent Document 2, in a coated tool provided with a fireproof coating layer on the surface of the tool substrate, the fireproof coating layer may be TiN from the surface side of the tool substrate, such as AlTiN having a low Al concentration. The PVD method is carried out by combining a layer having a cubic crystal structure and a layer adjacent to the layer and indicated by (Ti 1-x Al x ) N (atomic ratio x> 0.5). A coating tool having a laminated structure in which a plurality of sets are formed by using the coating tool and having a hexagonal structural phase of 0.5 to 15 wt% in the entire fireproof coating layer is described. It has been proposed to prolong the tool life by forming a coating layer having hardness and oxidation resistance.
近年の切削加工における省力化および省エネ化への要求は強く、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、長期の使用に亘ってのすぐれた耐摩耗性とすぐれた耐酸化性を有するとともに、かかる耐摩耗性等が十分に発揮できるよう、その前提として耐欠損性、耐チッピング性等の耐異常損傷性が求められている。
しかしながら、前記特許文献１、２に記載されている従来の被覆工具においては、低Ａｌ−ＡｌＴｉＮ層と高Ａｌ−ＡｌＴｉＮを積層化することにより、耐摩耗性と耐熱性を両立することができる被覆層は得られているものの、刃先に高負荷がかかるような切削、例えば、合金鋼等の高速切削等においては、それぞれの層において、チッピングや欠けの原因となる欠陥が発生してしまい、摩耗寿命に達する前に欠損により工具寿命に至ってしまうという問題を有していた。
In recent years, there has been a strong demand for labor saving and energy saving in cutting, and along with this, cutting tends to be faster and more efficient, and covering tools have excellent durability over a long period of use. In addition to having excellent wear resistance and oxidation resistance, abnormal damage resistance such as fracture resistance and chipping resistance is required as a premise so that such wear resistance and the like can be sufficiently exhibited.
However, in the conventional coating tools described in Patent Documents 1 and 2, by laminating a low Al-AlTiN layer and a high Al-AlTiN layer, both wear resistance and heat resistance can be achieved at the same time. Although layers have been obtained, in cutting where a high load is applied to the cutting edge, for example, high-speed cutting of alloy steel, etc., defects that cause chipping and chipping occur in each layer, resulting in wear. There was a problem that the tool life was reached due to a defect before reaching the life.
そこで、本発明者らは、前述の観点から、低Ａｌ−ＡｌＴｉＮ層（以下、「低Ａｌ層」ともいう。）と高Ａｌ−ＡｌＴｉＮ層（以下、「高Ａｌ層」ともいう。）とを交互に積層してなる硬質被覆層を物理蒸着法により形成してなる被覆工具について、合金鋼等の高速切削等に供した場合においても、すぐれた耐欠損性および耐チッピング性を有することによりチッピングや欠けを生じることなく、硬質被覆層が本来有する、すぐれた耐摩耗性と耐熱性とにより、長期の使用に亘ってすぐれた切削性能を発揮する被覆工具を開発すべく、チッピングや欠けの原因について、硬質被覆層を構成する各層内の結晶粒の結晶構造や結晶粒と層界面との関係について着目し研究を行った結果、以下の知見を得た。 Therefore, from the above viewpoint, the present inventors refer to a low Al-AlTiN layer (hereinafter, also referred to as "low Al layer") and a high Al-AlTiN layer (hereinafter, also referred to as "high Al layer"). A coating tool formed by alternately laminating hard coating layers by a physical vapor deposition method has excellent chipping resistance and chipping resistance even when it is used for high-speed cutting of alloy steel or the like. Causes of chipping and chipping in order to develop a coating tool that exhibits excellent cutting performance over a long period of time due to the excellent wear resistance and heat resistance inherent in the hard coating layer without causing chipping or chipping. As a result of conducting research focusing on the crystal structure of the crystal grains in each layer constituting the hard coating layer and the relationship between the crystal grains and the layer interface, the following findings were obtained.
即ち、本発明者らは、従来の前記特許文献１に記載される、工具基体に立方晶組織で構成される低Ａｌ−ＡｌＴｉＮ層と六方晶組織で構成される高Ａｌ−ＡｌＴｉＮ層とを交互に積層化した硬質被覆層を有する被覆工具、或いは、前記特許文献２に記載される、工具基体に対して、低Ａｌで立方晶構造を有するＡｌＴｉＮ結晶粒からなる層と、該層に隣接し、（Ｔｉ１−ｘＡｌｘ）Ｎ（原子比で、ｘ＞０．５）にて示される層とを一組とし、これらの層の複数組が積層構造を有して物理蒸着により成膜され、全体として０．５〜１５ｗｔ％の六方晶構造相を有する耐火被覆層を備えた被覆工具において、交互に積層される組成の異なる層内に存在する立方晶構造の結晶粒、および、六方晶構造の結晶粒が、いずれも、層間の境界面において分断される結果、すぐれた耐摩耗性や耐熱性による工具寿命を全うする前に、かかる境界面においてチッピングや欠けが発生し、工具として使用できなくなることを知見した。
そして、本発明者らは、かかる知見に基づいて、工具基体に低Ａｌ−ＡｌＴｉＮ層および高Ａｌ−ＡｌＴｉＮ層を交互に積層されてなる被覆層を有する被覆工具において、例えば、高Ａｌ−ＡｌＴｉＮ層において形成される六方晶構造の結晶粒を隣接する低Ａｌ−ＡｌＴｉＮ層との層間をまたがるように成長させることにより、結晶粒が分断されることにより生じていた層の境界面におけるチッピングや欠け発生の問題を解決し、すぐれた耐摩耗性や耐熱性特性に基づき、工具寿命の延長化を実現したものである。
That is, the present inventors alternately alternate a low Al-AlTiN layer composed of a cubic structure and a high Al-AlTiN layer composed of a hexagonal structure on the tool substrate described in the conventional Patent Document 1. Adjacent to the coating tool having a hard coating layer laminated on the above, or a layer made of AlTiN crystal grains having a cubic structure with low Al with respect to the tool substrate described in Patent Document 2, and adjacent to the layer. , (Ti 1-x Al x ) N (atomic ratio, x> 0.5) is set as one set, and a plurality of sets of these layers have a laminated structure and are formed by physical vapor deposition. In a coating tool provided with a fireproof coating layer having a hexagonal structural phase of 0.5 to 15 wt% as a whole, crystal grains having a cubic structure existing in layers having different compositions that are alternately laminated, and hexagonal crystals. As a result of the crystal grains having a crystal structure being divided at the interface between the layers, chipping or chipping occurs at the interface before the tool life due to excellent wear resistance and heat resistance is reached, and the crystal grain is used as a tool. It was found that it could not be used.
Then, based on such findings, the present inventors have found, for example, in a covering tool having a coating layer in which low Al-AlTiN layers and high Al-AlTiN layers are alternately laminated on a tool substrate, for example, a high Al-AlTiN layer. By growing the hexagonal crystal grains formed in (1) so as to straddle the layers with the adjacent low Al—AlTiN layer, chipping or chipping at the boundary surface of the layer caused by the fragmentation of the crystal grains occurs. The tool life has been extended based on the excellent wear resistance and heat resistance characteristics.
この発明は、上記の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および立方晶窒化ホウ素基超高圧焼結体のいずれかからなる工具基体の表面に硬質被覆層を有する表面被覆切削工具において、
前記硬質被覆層は、工具基体の表面より、低Ａｌ−ＡｌＴｉＮ層と高Ａｌ−ＡｌＴｉＮ層が交互に積層されてなる２層以上の多層被覆層であり、
（ａ）各層および被覆層全体の組成は、
低Ａｌ−ＡｌＴｉＮ層では、（ＡｌＸＴｉ１−Ｘ）Ｎ ０．５０≦ｘ＜０．７０（ｘは原子比）であり、立方晶組織を主相とし、
高Ａｌ−ＡｌＴｉＮ層では、（ＡｌｙＴｉ１−ｙ）Ｎ ０．７０≦ｙ≦０．９５（ｙは原子比）であり、六方晶組織を主相とし、
被覆層全体では、（ＡｌｚＴｉ１−ｚ）Ｎ ０．６０≦ｚ≦０．８５（ｚは原子比）であり、
（ｂ）各層の平均層厚および全硬質被覆層の平均膜厚は、
各低Ａｌ−ＡｌＴｉＮ層および各高Ａｌ−ＡｌＴｉＮ層では、それぞれ２〜３０ｎｍであり、被覆層全体では、０．５〜８．０μｍであり、
（ｃ）六方晶組織を形成する六方晶結晶粒は、少なくとも一組の高Ａｌ−ＡｌＴｉＮ層と該高Ａｌ−ＡｌＴｉＮ層と隣り合う低Ａｌ−ＡｌＴｉＮ層とに跨って成長しており、その層界面を跨る前記六方晶結晶粒の個数は、界面の単位面積０．０４μｍ２当たり２個以上であって、前記層界面に対する垂直長さが、２〜５０ｎｍであり、前記層界面に対して前記六方晶結晶粒が占める面積率は５％以上であることを特徴とする表面被覆切削工具。
（２） （１）において、前記層界面に対する垂直長さが２〜５０ｎｍである、前記六方晶組織を形成する六方晶結晶粒の前記高Ａｌ−ＡｌＴｉＮ層および前記低Ａｌ−ＡｌＴｉＮ層中における前記垂直方向長さの比が、１：２〜２：１であることを特徴とする表面被覆切削工具。
（４）（１）または（２）において、前記六方晶組織を形成する六方晶結晶粒は、高Ａｌ−ＡｌＴｉＮ層を含む三層以上に跨って成長していることを特徴とする表面被覆切削工具。」
を特徴とするものである。
The present invention has been made based on the above findings.
"(1) In a surface-coated cutting tool having a hard coating layer on the surface of a tool substrate made of any one of a tungsten carbide-based cemented carbide, a titanium nitride-based cermet, and a cubic boron nitride-based ultrahigh-pressure sintered body.
The hard coating layer is two or more multilayer coating layers in which low Al-AlTiN layers and high Al-AlTiN layers are alternately laminated from the surface of the tool substrate.
(A) The composition of each layer and the entire coating layer is
In the low Al—AlTiN layer, (Al X Ti 1-X ) N 0.50 ≦ x <0.70 (x is an atomic ratio), and the cubic structure is the main phase.
In the high Al—AlTiN layer, (Al y Ti 1-y ) N 0.70 ≦ y ≦ 0.95 (y is an atomic ratio), and the hexagonal structure is the main phase.
In the entire coating layer, (Al z Ti 1-z ) N 0.60 ≦ z ≦ 0.85 (z is an atomic ratio).
(B) The average thickness of each layer and the average film thickness of all hard coating layers are
Each low Al-AlTiN layer and each high Al-AlTiN layer is 2 to 30 nm, and the entire coating layer is 0.5 to 8.0 μm.
(C) The hexagonal crystal grains forming the hexagonal structure grow over at least one set of high Al-AlTiN layers and a low Al-AlTiN layer adjacent to the high Al-AlTiN layers, and the layers thereof. the hexagonal grains of the number across the interface, I unit area 0.04 .mu.m 2 per two or more der surfactants, vertical length to layer interface is a 2 to 50 nm, with respect to the layer interface surface-coated cutting tool area ratio where the hexagonal crystal grains occupied, characterized in der Rukoto more than 5%.
(2) In (1), the hexagonal crystal grains forming the hexagonal structure having a vertical length of 2 to 50 nm with respect to the layer interface are described in the high Al-AlTiN layer and the low Al-AlTiN layer. A surface-coated cutting tool characterized by a vertical length ratio of 1: 2 to 2: 1.
(4) In (1) or (2), the hexagonal crystal grains forming the hexagonal structure are surface-coated cutting characterized in that they grow over three or more layers including a high Al—AlTiN layer. tool. "
It is characterized by.
つぎに、この発明の被覆工具について、詳細に説明する。 Next, the covering tool of the present invention will be described in detail.
硬質被覆層の平均膜厚；
硬質被覆層は、交互に積層されてなる低Ａｌ−ＡｌＴｉＮ層と高Ａｌ−ＡｌＴｉＮ層のすべてからなり、その平均膜厚は、０．５μｍ未満では、長期にわたり耐摩耗性を発揮することができず、一方、８．０μｍを超えると全体被覆層として欠損やチッピングが発生し易くなるため、全体で０．５〜８．０μｍとする。
硬質被覆層の平均膜厚は、工具基体に垂直な方向の断面において、走査型電子顕微鏡（ＳＥＭ）または透過型電子顕微鏡（ＴＥＭ）を用いて測定することができる。
Average film thickness of hard coating layer;
The hard coating layer is composed of all of low Al-AlTiN layers and high Al-AlTiN layers which are laminated alternately, and when the average film thickness is less than 0.5 μm, wear resistance can be exhibited for a long period of time. On the other hand, if it exceeds 8.0 μm, defects and chipping are likely to occur as the entire coating layer, so the total thickness is set to 0.5 to 8.0 μm.
The average thickness of the hard coating layer can be measured using a scanning electron microscope (SEM) or a transmission electron microscope (TEM) in a cross section in a direction perpendicular to the tool substrate.
硬質被覆層の全体組成；
硬質被覆層全体では、組成式：（ＡｌｚＴｉ１−ｚ）Ｎで表した場合、 ０．６０≦ｚ≦０．８５を満足する（ただし、ｚは原子比）平均組成を有することが必要である。
すなわち、Ａｌ成分の平均組成が、０．６０未満では、高速切削において被覆層の耐熱性が発揮されず、一方、Ａｌ成分の平均組成が、０．８５を超えると十分な耐摩耗性が発揮されないためである。
硬質被覆層の全体組成の測定については、ＡｌＴｉＮ層における膜厚方向の断面視野範囲においてＡｌ成分の組成をＳＥＭ−ＥＤＳ法により面分析することにより、その測定値の平均値を平均組成として求めることができる。
Overall composition of the hard coating layer;
The entire hard coating layer needs to have an average composition satisfying 0.60 ≦ z ≦ 0.85 (where z is an atomic ratio) when expressed by the composition formula: (Al z Ti 1-z) N. Is.
That is, when the average composition of the Al component is less than 0.60, the heat resistance of the coating layer is not exhibited in high-speed cutting, while when the average composition of the Al component exceeds 0.85, sufficient wear resistance is exhibited. This is because it is not done.
Regarding the measurement of the overall composition of the hard coating layer, the composition of the Al component in the cross-sectional visual field range in the film thickness direction of the AlTiN layer is surface-analyzed by the SEM-EDS method, and the average value of the measured values is obtained as the average composition. Can be done.
低Ａｌ−ＡｌＴｉＮ層、および、高Ａｌ−ＡｌＴｉＮ層の平均層厚；
それぞれの層の平均層厚は、２ｎｍ以上、３０ｎｍ以下とする。
すなわち、高Ａｌ−ＡｌＴｉＮ層では、平均層厚が、２ｎｍ未満では、耐熱性向上効果が望めず、３０ｎｍを超えると、耐熱性が飽和する一方、膜全体として耐摩耗性の低下が顕著となる。
他方、低Ａｌ−ＡｌＴｉＮ層では、平均層厚が、２ｎｍ未満では、耐摩耗性向上効果が望めず、３０ｎｍを超えると、耐摩耗性が飽和する一方、膜全体として耐熱性の低下が顕著となるためである。
低Ａｌ−ＡｌＴｉＮ層、および、高Ａｌ−ＡｌＴｉＮ層の平均層厚の測定については、縦断面のＴＥＭ−ＥＤＳマッピングにより得られた高Ａｌ−ＡｌＴｉＮ層および低Ａｌ−ＡｌＴｉＮ層のそれぞれの平均層厚として求めることができる。
Average layer thickness of low Al-AlTiN layer and high Al-AlTiN layer;
The average layer thickness of each layer is 2 nm or more and 30 nm or less.
That is, in the high Al—AlTiN layer, if the average layer thickness is less than 2 nm, the effect of improving heat resistance cannot be expected, and if it exceeds 30 nm, the heat resistance is saturated, but the wear resistance of the entire film is significantly reduced. ..
On the other hand, in the low Al-AlTiN layer, if the average layer thickness is less than 2 nm, the effect of improving the abrasion resistance cannot be expected, and if it exceeds 30 nm, the abrasion resistance is saturated, but the heat resistance of the entire film is significantly reduced. This is to become.
Regarding the measurement of the average layer thickness of the low Al-AlTiN layer and the high Al-AlTiN layer, the average layer thickness of each of the high Al-AlTiN layer and the low Al-AlTiN layer obtained by TEM-EDS mapping of the vertical cross section was obtained. Can be obtained as.
低Ａｌ−ＡｌＴｉＮ層、および、高Ａｌ−ＡｌＴｉＮ層の平均組成；
低Ａｌ−ＡｌＴｉＮ層では、組成式：（ＡｌＸＴｉ１−Ｘ）Ｎで表した場合、０．５０≦ｘ＜０．７０を満足する（ただし、ｘは原子比）平均組成を有することが必要である。
すなわち、低Ａｌ−ＡｌＴｉＮ層は、硬質被覆層において、耐摩耗性を付与する層であるが、Ａｌ成分の平均組成が、０．５０未満では、耐摩耗性および耐熱性が低下し、膜全体の耐摩耗性の低下の原因となり、０．７０以上では、層自体の強度が低下し、膜全体においても高温強度が低下するためである。
また、高Ａｌ−ＡｌＴｉＮ層では、組成式：（ＡｌｙＴｉ１−ｙ）Ｎで表した場合、０．７０≦ｙ≦０．９５を満足する（ただし、ｙは原子比）平均組成を有することが必要である。すなわち、高Ａｌ−ＡｌＴｉＮ層は、硬質被覆層において、耐熱性を付与する層であるが、Ａｌ成分の平均組成が、０．７０未満では、高Ａｌ−ＡｌＴｉＮ層における耐酸化性が発揮されず、０．９５を超えると高Ａｌ−ＡｌＴｉＮ層のみだけではなく、膜全体の硬度を低下させ、耐摩耗性を損なうためである。
低Ａｌ−ＡｌＴｉＮ層、および、高Ａｌ−ＡｌＴｉＮ層の平均組成は、各層について、ＴＥＭ断面観察によるＥＤＳにて、ＡｌとＴｉの合量に対するＡｌの平均組成（原子比）として求めることができる。
Average composition of low Al-AlTiN layer and high Al-AlTiN layer;
The low Al—AlTiN layer may have an average composition of 0.50 ≦ x <0.70 (where x is an atomic ratio) when expressed by the composition formula: (Al X Ti 1-X) N. is necessary.
That is, the low Al-AlTiN layer is a layer that imparts abrasion resistance in the hard coating layer, but if the average composition of the Al component is less than 0.50, the abrasion resistance and heat resistance are lowered, and the entire film. This is because the wear resistance of the film is lowered, and when it is 0.70 or more, the strength of the layer itself is lowered, and the high temperature strength of the entire film is also lowered.
Further, the high Al—AlTiN layer has an average composition satisfying 0.70 ≦ y ≦ 0.95 (where y is an atomic ratio) when expressed by the composition formula: (Al y Ti 1-y) N. It is necessary. That is, the high Al—AlTiN layer is a layer that imparts heat resistance in the hard coating layer, but if the average composition of the Al component is less than 0.70, the oxidation resistance in the high Al—AlTiN layer is not exhibited. If it exceeds 0.95, not only the high Al—AlTiN layer but also the hardness of the entire film is lowered, and the wear resistance is impaired.
The average composition of the low Al—AlTiN layer and the high Al—AlTiN layer can be determined as the average composition (atomic ratio) of Al with respect to the total amount of Al and Ti by EDS by TEM cross-sectional observation for each layer.
層境界面を跨ぐ六方晶微細結晶粒の特定方法、および、その測定内容；
被覆層の縦断面に対するＴＥＭ観察においては、回折図形として、六方晶（１１０）面のデバイスリングを得ることができる。このデバイスリングの一部に対物絞りを挿入し結像させることで得られた暗視野像において、六方晶結晶粒の（１１０）面の存在を示す光る箇所（以下、「光点」という。）が、それぞれが単独で或いは複数重なりあって一つの集合体を構成しており、これらをそれぞれ六方晶結晶粒と定めた。
次に、同一の観察領域において、ＴＥＭ−ＥＤＳを用いて得られた、高Ａｌ−ＡｌＴｉＮ層と低Ａｌ−ＡｌＴｉＮ層の層界面断面像と、前記の暗視野像とを突き合わせることにより、層界面を跨る六方晶結晶粒を特定できるため、単位面積当たり（０．２μｍ×０．２μｍ）の層界面を跨ぐ六方晶結晶粒の個数、および、その内数として、界面垂直方向長さが２〜５０ｎｍである前記六方晶結晶粒の個数を測定し、さらに、この界面垂直方向長さが２〜５０ｎｍである、前記六方晶結晶粒について、その最長長さ、高Ａｌ層および低Ａｌ層中における垂直長さの比が１：２〜２：１であるものの個数、層界面においてそれら結晶粒が占める面積率、および、三層以上に跨る前記六方晶結晶粒の個数についても測定を行った。
Method for identifying hexagonal fine crystal grains that straddle the layer boundary surface, and the measurement contents;
In the TEM observation of the longitudinal section of the coating layer, a hexagonal (110) plane device ring can be obtained as a diffraction pattern. In the dark field image obtained by inserting an objective diaphragm into a part of this device ring and forming an image, a shining portion indicating the existence of the (110) plane of the hexagonal crystal grain (hereinafter referred to as "light spot"). However, each of them constitutes one aggregate individually or by overlapping with each other, and these are defined as hexagonal crystal grains.
Next, in the same observation region, the layer interface cross-sectional image of the high Al-AlTiN layer and the low Al-AlTiN layer obtained by using TEM-EDS is compared with the above-mentioned dark field image to form a layer. Since the hexagonal crystal grains that straddle the interface can be specified, the number of hexagonal crystal grains that straddle the layer interface per unit area (0.2 μm × 0.2 μm), and the number of the hexagonal crystal grains, the length in the vertical direction of the interface is 2. The number of the hexagonal crystal grains having a diameter of about 50 nm is measured, and further, the hexagonal crystal grains having an interface vertical length of 2 to 50 nm have the longest length, among the high Al layer and the low Al layer. The number of those having a vertical length ratio of 1: 2 to 2: 1, the area ratio occupied by those crystal grains at the layer interface, and the number of the hexagonal crystal grains spanning three or more layers were also measured. ..
高Ａｌ層と低Ａｌ層との層界面を跨る六方晶結晶粒の個数、界面垂直方向長さが２〜５０ｎｍである前記六方晶結晶粒の個数、界面垂直方向長さの最長長さ、低Ａｌ層と高Ａｌ層における界面垂直方向長さ比と個数、および、層界面において前記六方晶結晶粒が占める面積率；
本発明では、層界面を跨る六方晶結晶粒の個数の密度として、被覆層の複数の縦断面、例えば、５つの縦断面にて、０．２μｍ×０．２μｍの領域に存在する複数の層界面の全長に対して層界面を跨ぐ六方晶結晶粒の個数の平均値を用い評価した。層界面の単位面積を０．０４μｍ２とした場合、層界面を跨る六方晶結晶粒の個数が２個以上であれば、耐チッピング特性等の諸効果が発揮できるが、特に、５個以上の場合は、すぐれた効果を発揮することができる。
高Ａｌ−ＡｌＴｉＮ層と低Ａｌ−ＡｌＴｉＮ層の層界面を跨って存在する六方晶結晶粒の粒径は、界面の垂直方向でみたときに２ｎｍ以上５０ｎｍ以下の長さを有することが特に望ましい。
すなわち、六方晶結晶粒は、高Ａｌ−ＡｌＴｉＮ層と低Ａｌ−ＡｌＴｉＮ層の層界面を跨って存在することにより、結晶粒が層界面で脱落し、チッピングや欠損が生じることを回避するものであるが、前記結晶粒径の界面に対する垂直方向長さが２ｎｍ未満では、一定レベル以上の界面における欠陥抑制効果は有するものの、十分に発揮できない場合があり、また、前記結晶粒径の界面に対する垂直方向長さが５０ｎｍを超える場合には、結晶粒の層界面からの脱落防止効果が飽和するため、界面に対する垂直方向長さについては、特に、欠陥抑制効果が十分に発揮でき、被覆層の軟化や、耐摩耗性の低下が生ずることなく、層界面からの結晶粒の脱落抑制効果を有する２ｎｍ以上５０ｎｍ以下の長さ範囲を望ましい範囲と規定した。
また、本発明では、さらに、前記界面の垂直方向でみたときに２ｎｍ以上５０ｎｍ以下の長さを有する前記層界面を跨る六方晶結晶粒の面積率として、被覆層の複数の縦断面、例えば、５つの縦断面について、０．２μｍ×０．２μｍの領域に存在する複数の層界面の全長に対する六方晶結晶粒が跨ぐ層界面の長さの比率の平均値を用い、評価を行った。六方晶結晶粒が層界面を跨る面積率が、３％以上であれば、耐チッピング特性等の諸効果が発揮でき、特に、５％を超える場合には、すぐれた効果を発揮することができる。
また、本発明は、高Ａｌ−ＡｌＴｉＮ層中の六方晶結晶粒が、低Ａｌ−ＡｌＴｉＮ層との層界面を越えて低Ａｌ−ＡｌＴｉＮ層中に存在することにより、すでに、耐チッピング特性等のすぐれた特性を有するものであるので、隣り合う層中における六方晶結晶粒の層界面垂直方向における長さ比については特段の特定を行う必要はないが、バランスのとれた耐チッピング特性を得るためには、それぞれの層における六方晶結晶粒の界面垂直方向における長さ比は、１：２〜２：１であることが好ましい。
さらに、前記の六方晶組織を形成する六方晶結晶粒は、連続する３層以上のＡｌＴｉＮ層に跨って成長していること、すなわち、例えば、連続する低Ａｌ−ＡｌＴｉＮ層、高Ａｌ−ＡｌＴｉＮ層、低Ａｌ−ＡｌＴｉＮ層の順により、或いは、連続する高Ａｌ−ＡｌＴｉＮ層、低Ａｌ−ＡｌＴｉＮ層、高Ａｌ−ＡｌＴｉＮ層の順により、これらの層を跨って成長することによりすぐれた耐チッピング性を発揮することができる。
The number of hexagonal crystal grains straddling the layer interface between the high Al layer and the low Al layer, the number of the hexagonal crystal grains having a vertical interface length of 2 to 50 nm, the longest vertical interface length, and low The vertical length ratio and number of the Al layer and the high Al layer, and the area ratio occupied by the hexagonal crystal grains at the layer interface;
In the present invention, as the density of the number of hexagonal crystal grains straddling the layer interface, a plurality of layers existing in a region of 0.2 μm × 0.2 μm in a plurality of longitudinal sections of the coating layer, for example, five longitudinal sections. The evaluation was performed using the average value of the number of hexagonal crystal grains straddling the layer interface with respect to the total length of the interface. When the unit area of the layer interface is 0.04 μm 2 , various effects such as chipping resistance can be exhibited if the number of hexagonal crystal grains straddling the layer interface is 2 or more, but in particular, 5 or more. In that case, an excellent effect can be exhibited.
It is particularly desirable that the particle size of the hexagonal crystal grains existing across the layer interface between the high Al-AlTiN layer and the low Al-AlTiN layer has a length of 2 nm or more and 50 nm or less when viewed in the vertical direction of the interface.
That is, since the hexagonal crystal grains are present across the layer interface between the high Al-AlTiN layer and the low Al-AlTiN layer, the crystal grains are prevented from falling off at the layer interface, causing chipping and chipping. However, if the length in the direction perpendicular to the interface of the crystal grain size is less than 2 nm, although it has a defect suppressing effect at the interface above a certain level, it may not be sufficiently exhibited, and it is perpendicular to the interface of the crystal grain size. When the directional length exceeds 50 nm, the effect of preventing the crystal grains from falling off from the layer interface is saturated. Therefore, with respect to the length in the direction perpendicular to the interface, the defect suppressing effect can be sufficiently exhibited and the coating layer is softened. Further, a length range of 2 nm or more and 50 nm or less, which has an effect of suppressing the dropping of crystal grains from the layer interface without causing a decrease in wear resistance, is defined as a desirable range.
Further, in the present invention, a plurality of vertical cross sections of the coating layer, for example, as an area ratio of hexagonal crystal grains straddling the layer interface having a length of 2 nm or more and 50 nm or less when viewed in the vertical direction of the interface, for example. The five vertical cross sections were evaluated using the average value of the ratio of the length of the layer interface straddled by the hexagonal crystal grains to the total length of the plurality of layer interfaces existing in the region of 0.2 μm × 0.2 μm. When the area ratio of hexagonal crystal grains straddling the layer interface is 3% or more, various effects such as chipping resistance can be exhibited, and especially when it exceeds 5%, excellent effects can be exhibited. ..
Further, in the present invention, the hexagonal crystal grains in the high Al-AlTiN layer are present in the low Al-AlTiN layer beyond the layer interface with the low Al-AlTiN layer, so that the chipping resistance and the like are already exhibited. Since it has excellent properties, it is not necessary to specify the length ratio of hexagonal crystal grains in the adjacent layers in the direction perpendicular to the layer interface, but in order to obtain balanced chipping resistance. The length ratio of hexagonal crystal grains in each layer in the direction perpendicular to the interface is preferably 1: 2 to 2: 1.
Further, the hexagonal crystal grains forming the hexagonal structure are grown over three or more continuous AlTiN layers, that is, for example, a continuous low Al-AlTiN layer and a high Al-AlTiN layer. Excellent chipping resistance by growing across these layers in the order of low Al-AlTiN layers, or in the order of continuous high Al-AlTiN layers, low Al-AlTiN layers, and high Al-AlTiN layers. Can be demonstrated.
硬質被覆層の成膜方法；
本発明の低Ａｌ−ＡｌＴｉＮ層と高Ａｌ−ＡｌＴｉＮ層とが交互に積層されてなる硬質被覆層は、例えば、以下の方法により成膜することができる。
図３（ａ）、（ｂ）に、本発明の硬質被覆層を成膜するための、アークイオンプレーティング装置の概略図を示す。
図３（ａ）、（ｂ）に示すアークイオンプレーティング装置内に、組成の異なる低Ａｌ−ＡｌＴｉＮ層形成用Ａｌ−Ｔｉ合金ターゲットおよび高Ａｌ−ＡｌＴｉＮ層形成用Ａｌ−Ｔｉ合金ターゲットを配置するとともに、ＷＣ基超硬合金、ＴｉＣＮ基サーメットあるいはｃＢＮ基超高圧焼結体のいずれかからなる工具基体をアークイオンプレーティング装置内の回転テーブル上に載置し、工具基体に対するボンバード前処理および工具基体の温度、Ｎ２ガス圧、成膜時のバイアス電圧、および、アーク電流を調整し、アーク放電を発生させることにより、本発明の低Ａｌ−ＡｌＴｉＮ層と高Ａｌ−ＡｌＴｉＮ層とが交互に積層されてなる硬質被覆層を成膜することができる。
特に、低Ａｌ−ＡｌＴｉターゲットと高Ａｌ−ＡｌＴｉターゲットとによる同時蒸着法を用い、成膜時の基体温度、バイアス電圧、アーク電流値、および、テーブル回転数を制御することにより、本発明により規定される、六方晶結晶粒が積層される高Ａｌ−ＡｌＴｉＮ層と隣接する低Ａｌ−ＡｌＴｉＮ層を跨いで析出した多層硬質被覆層を有する被覆工具を得ることができる。
Method of forming a hard coating layer;
The hard coating layer formed by alternately laminating low Al-AlTiN layers and high Al-AlTiN layers of the present invention can be formed by, for example, the following method.
3 (a) and 3 (b) show schematic views of an arc ion plating apparatus for forming the hard coating layer of the present invention.
In the arc ion plating apparatus shown in FIGS. 3 (a) and 3 (b), an Al—Ti alloy target for forming a low Al—AlTiN layer and an Al—Ti alloy target for forming a high Al—AlTiN layer having different compositions are arranged. At the same time, a tool substrate made of either a WC-based cemented carbide, a TiCN-based cermet or a cBN-based ultrahigh-pressure sintered body is placed on a rotary table in an arc ion plating apparatus, and a bombard pretreatment and a tool for the tool substrate are placed. temperature of the substrate, N 2 gas pressure, bias voltage during film formation, and to adjust the arc current, by generating arc discharge, alternately with a low Al-AlTiN layer and a high Al-AlTiN layer of the present invention A laminated hard coating layer can be formed.
In particular, it is defined by the present invention by controlling the substrate temperature, bias voltage, arc current value, and table rotation speed at the time of film formation by using the simultaneous vapor deposition method using a low Al-AlTi target and a high Al-AlTi target. It is possible to obtain a coating tool having a multilayer hard coating layer precipitated across a high Al-AlTiN layer on which hexagonal crystal grains are laminated and an adjacent low Al-AlTiN layer.
本発明の被覆工具は、低Ａｌ−ＡｌＴｉＮ層と高Ａｌ−ＡｌＴｉＮ層とが交互に積層されてなる多層硬質被覆層を有することにより、耐摩耗性と耐熱性を両立して有し、しかも、被覆層中に存在する六方晶結晶粒が、低Ａｌ−ＡｌＴｉＮ層と高Ａｌ−ＡｌＴｉＮ層の境界面を跨いで存在することにより、被覆層全体の耐チッピング性、および、耐欠損性が向上する結果、合金鋼の高速切削においても、チッピングや欠けが生じることがなく、すぐれた耐摩耗性や耐熱性特性に基づく工具寿命の延長化を実現できる。 The coating tool of the present invention has both wear resistance and heat resistance by having a multilayer hard coating layer in which low Al-AlTiN layers and high Al-AlTiN layers are alternately laminated. Since the hexagonal crystal grains existing in the coating layer are present across the interface between the low Al-AlTiN layer and the high Al-AlTiN layer, the chipping resistance and fracture resistance of the entire coating layer are improved. As a result, even in high-speed cutting of alloy steel, chipping and chipping do not occur, and the tool life can be extended based on excellent wear resistance and heat resistance characteristics.
つぎに、この発明の被覆工具を実施例により具体的に説明する。
なお、具体的な説明としては、ＷＣ基超硬合金を工具基体とする被覆工具について説明するが、ＴｉＣＮ基サーメットあるいは立方晶窒化ホウ素焼結体を工具基体とする被覆工具についても同様である。
Next, the covering tool of the present invention will be specifically described with reference to Examples.
As a specific description, a covering tool using a WC-based cemented carbide as a tool base will be described, but the same applies to a covering tool using a TiCN-based cermet or a cubic boron nitride sintered body as a tool base.
工具基体の作製；
原料粉末として、いずれも０．５〜５μｍの平均粒径を有するＣｏ粉末、ＶＣ粉末、ＴａＣ粉末、ＮｂＣ粉末、Ｃｒ３Ｃ２粉末、およびＷＣ粉末を用意し、これら原料粉末を、表１に示される配合組成に配合し、更にワックスを加えてボールミルで７２時間湿式混合し、減圧乾燥した後、１００ＭＰａの圧力でプレス成形し、これらの圧粉成形体を焼結し、所定寸法となるように加工して、ＩＳＯ規格ＳＥＥＮ１２０３ＡＦＥＮのインサート形状をもったＷＣ基超硬合金製の工具基体１〜２を製造した。
Preparation of tool base;
As raw material powders, Co powder, VC powder, TaC powder, NbC powder, Cr 3 C 2 powder, and WC powder having an average particle size of 0.5 to 5 μm are prepared, and these raw material powders are shown in Table 1. It is blended to the blending composition shown, further waxed, wet-mixed in a ball mill for 72 hours, dried under reduced pressure, press-molded at a pressure of 100 MPa, and these powder compacts are sintered to obtain a predetermined size. To manufacture tool substrates 1 and 2 made of WC-based superhard alloy having an insert shape of ISO standard SEEN1203AFEN.
上記の工具基体１〜２のそれぞれを、アセトン中で超音波洗浄し、乾燥した状態で、図３に示されるアークイオンプレーティング装置内の回転テーブル上の中心軸から半径方向に所定距離離れた位置に外周部に沿って装着し、前記回転テーブルを挟んで対向する位置に、低Ａｌ−ＡｌＴｉＮ層形成用Ａｌ−Ｔｉ合金ターゲットおよび高Ａｌ−ＡｌＴｉＮ層形成用Ａｌ−Ｔｉ合金ターゲット（カソード電極）を配置し、
まず、装置内を排気して真空に保持しながら、ヒーターで工具基体を４５０℃に加熱した後、前記回転テーブル上で自転しながら回転する工具基体に−１０００Ｖの直流バイアス電圧を印加し、かつ、Ａｌ−Ｔｉ合金ターゲット（カソード電極）に１００Ａのアーク電流を流してアーク放電を発生させ、もって工具基体表面をボンバード洗浄する。
次に、装置内に反応ガスとして窒素ガスを導入し、表２に示すＮ２ガス圧を保持し、回転テーブル上で自転しながら回転する工具基体の温度を表２に示す温度範囲に維持するとともに、表２にて示す直流バイアス電圧を印加し、かつ、低Ａｌ−ＡｌＴｉＮ層形成用のＡｌ−Ｔｉ合金ターゲットと対応するアノード電極との間、および、高Ａｌ−ＡｌＴｉＮ層形成用のＡｌ−Ｔｉ合金ターゲットと対応するアノード電極との間のそれぞれに対し、表２にて示されるアーク電流を流し、アーク放電を発生させ、前記工具基体の表面に、低Ａｌ−ＡｌＴｉＮ層、および、高Ａｌ−ＡｌＴｉＮ層を交互に物理蒸着により成膜することにより、表４にて示す、本発明被覆工具（以下、「本発明工具」という。）１〜１０（本発明工具９は参考例である）を作製した。
Each of the above tool substrates 1 and 2 was ultrasonically cleaned in acetone, dried, and separated from the central axis on the rotary table in the arc ion plating apparatus shown in FIG. 3 by a predetermined distance in the radial direction. An Al-Ti alloy target for forming a low Al—AlTiN layer and an Al—Ti alloy target for forming a high Al—AlTiN layer (cathode electrode) are mounted at positions along the outer peripheral portion and opposite to each other across the rotary table. Place and
First, the tool substrate is heated to 450 ° C. with a heater while the inside of the device is exhausted and kept in a vacuum, and then a DC bias voltage of −1000 V is applied to the tool substrate that rotates while rotating on the rotary table. , An arc current of 100 A is passed through the Al—Ti alloy target (cathode electrode) to generate an arc discharge, and the surface of the tool substrate is vacuum-cleaned.
Next, nitrogen gas is introduced as a reaction gas into the apparatus, the N 2 gas pressure shown in Table 2 is maintained, and the temperature of the tool substrate rotating while rotating on the rotary table is maintained in the temperature range shown in Table 2. At the same time, the DC bias voltage shown in Table 2 is applied, and between the Al—Ti alloy target for forming the low Al—AlTiN layer and the corresponding anode electrode, and Al— for forming the high Al—AlTiN layer. An arc current shown in Table 2 is passed between each of the Ti alloy target and the corresponding anode electrode to generate an arc discharge, and a low Al—AlTiN layer and a high Al are formed on the surface of the tool substrate. −AlTiN layers are alternately formed by physical vapor deposition to form a film, and the covering tool of the present invention (hereinafter referred to as “the tool of the present invention”) 1 to 10 (the tool 9 of the present invention is a reference example) shown in Table 4. Was produced.
比較の目的で、本発明例と同じく、図３に示すアークイオンプレーティング装置を用い、工具基体１〜２に対して、前記した本発明例と同様に、超音波洗浄、乾燥後、低Ａｌ−ＡｌＴｉＮ層形成用Ａｌ−Ｔｉ合金ターゲットおよび高Ａｌ−ＡｌＴｉＮ層形成用Ａｌ−Ｔｉ合金ターゲット（カソード電極）の配置を行い、装置内を排気して真空に保持しながら、ヒーターで工具基体を４５０℃に加熱した後、回転テーブル上で自転しながら回転する工具基体に対し、本発明例と同条件にてボンバート洗浄を行った。
次いで、本発明例と同様の手順にて、表３にて示す成膜条件にて成膜を行うことにより、表５にて示す、比較例被覆工具（以下、「比較例工具」という。）１〜１０を作製した。
For the purpose of comparison, the arc ion plating apparatus shown in FIG. 3 is used as in the example of the present invention, and the tool substrates 1 and 2 are subjected to ultrasonic cleaning, drying, and low alloy as in the above-mentioned example of the present invention. Arrange the Al—Ti alloy target for forming the −AlTiN layer and the Al—Ti alloy target (cathode electrode) for forming the high Al—AlTiN layer, and while exhausting the inside of the device and holding it in a vacuum, 450 the tool substrate with the heater. After heating to ° C., the tool substrate rotating while rotating on the rotary table was subjected to bombing cleaning under the same conditions as in the example of the present invention.
Next, by performing film formation under the film forming conditions shown in Table 3 in the same procedure as in the example of the present invention, the comparative example covering tool (hereinafter referred to as “comparative example tool”) shown in Table 5 is used. 1 to 10 were prepared.
上記で作製した本発明工具１〜１０（本発明工具９は参考例である）および比較例工具１〜１０の硬質被覆層の平均膜厚は、走査型電子顕微鏡（倍率５０００倍）を用いて測定された工具基体に垂直な方向の断面の観察視野内の５点の層厚の平均値として求め、表４および表５に示す。
また、硬質被覆層全体の組成については、ＡｌＴｉＮ層におけるＡｌ成分の組成をＳＥＭ−ＥＤＳにより５箇所の膜厚方向の視野範囲にて面分析し、その測定値の平均値を平均組成として求め、表４および表５に示す。
The average thickness of the hard coating layer of the tools 1 to 10 of the present invention (the tool 9 of the present invention is a reference example) and the tools 1 to 10 of the comparative example produced above are measured by using a scanning electron microscope (magnification: 5000 times). It was obtained as the average value of the layer thicknesses of 5 points in the observation field of the cross section in the direction perpendicular to the measured tool substrate, and is shown in Tables 4 and 5.
Regarding the composition of the entire hard coating layer, the composition of the Al component in the AlTiN layer was surface-analyzed at five locations in the visual field range in the film thickness direction by SEM-EDS, and the average value of the measured values was obtained as the average composition. It is shown in Table 4 and Table 5.
また、作製した本発明工具１〜１０（本発明工具９は参考例である）および比較例工具１〜１０の硬質被覆層の低Ａｌ−ＡｌＴｉＮ層および高Ａｌ−ＡｌＴｉＮ層の平均層厚については、縦断面のＴＥＭ−ＥＤＳマッピングにより得られた高Ａｌ−ＡｌＴｉＮ層および低Ａｌ−ＡｌＴｉＮ層について、各層を５点測定した平均値を用い、また、各層の成分組成については、前記ＴＥＭ−ＥＤＳマッピングにより得られた高Ａｌ−ＡｌＴｉＮ層および低Ａｌ−ＡｌＴｉＮ層について、各層の５点測定により、ＡｌとＴｉの合量に対するＡｌの平均組成（原子比）として求め、表４および表５に示す。 Regarding the average thickness of the low Al-AlTiN layer and the high Al-AlTiN layer of the hard coating layers of the manufactured tools 1 to 10 of the present invention (tool 9 of the present invention is a reference example) and the tools 1 to 10 of the comparative example. For the high Al-AlTiN layer and the low Al-AlTiN layer obtained by TEM-EDS mapping in the vertical cross section, the average value obtained by measuring 5 points of each layer was used, and the component composition of each layer was described in the TEM-EDS mapping. The high Al-AlTiN layer and the low Al-AlTiN layer obtained in the above method were obtained as the average composition (atomic ratio) of Al with respect to the total amount of Al and Ti by 5-point measurement of each layer, and are shown in Tables 4 and 5.
また、作製した本発明工具１〜１０（本発明工具９は参考例である）および比較例工具１〜１０の硬質被覆層について、段落００１６に記載された手法により測定された、低Ａｌ−ＡｌＴｉＮ層と高Ａｌ−ＡｌＴｉＮ層の層界面を跨る六方晶結晶粒の結晶粒径、所定の層界面面積あたりの層界面を跨る六方晶結晶粒の個数および面積率を表４および表５に示す。 Further, the hard coating layers of the prepared tools 1 to 10 of the present invention (tool 9 of the present invention is a reference example) and the hard coating layers of the comparative example tools 1 to 10 were measured by the method described in paragraph 0016, and the low Al-AlTiN was measured. Tables 4 and 5 show the crystal grain size of the hexagonal crystal grains straddling the layer interface between the layer and the high Al—AlTiN layer, and the number and area ratio of the hexagonal crystal grains straddling the layer interface per predetermined layer interface area.
次いで、本発明工具１〜１０（本発明工具９は参考例である）、比較例工具１〜１０について、以下の条件にて。高速断続切削の一種であるインサートによるフライス切削加工試験を実施し、切刃の逃げ面耐摩幅を測定した。
工具基体： 炭化タングステン基超硬合金
切削試験： 乾式高速正面フライス、センターカット切削、
被削材 ： ＪＩＳ・ＳＣＭ４４０ 幅１００ｍｍ、長さ３５０ｍｍのブロック材、
切削速度： ３５０ｍｍ／ｍｉｎ
切り込み： ２．０ｍｍ
一刃送り量：０．２５ｍｍ／刃
切削時間： １０ 分
表６に、試験結果を示す。
Next, the tools 1 to 10 of the present invention (the tool 9 of the present invention is a reference example) and the tools 1 to 10 of the comparative example are under the following conditions. A milling test using an insert, which is a type of high-speed intermittent cutting, was carried out, and the flank abrasion resistance width of the cutting edge was measured.
Tool Base: Tungsten Carbide Cemented Carbide Cutting Test: Dry High Speed Face Milling, Center Cut Cutting,
Work material: JIS / SCM440 Block material with a width of 100 mm and a length of 350 mm,
Cutting speed: 350 mm / min
Notch: 2.0 mm
Single blade feed amount: 0.25 mm / blade cutting time: 10 minutes
Table 6 shows the test results.
表６に示される結果から、本発明の被覆工具は、高Ａｌ−ＡｌＴｉＮ層と低Ａｌ−ＡｌＴｉＮ層とが交互に積層されてなる多層硬質被覆層を有することにより、耐摩耗性および耐熱性に優れ、しかも、前記被覆層中に存在する六方晶結晶粒が、高Ａｌ−ＡｌＴｉＮ層と低Ａｌ−ＡｌＴｉＮ層の境界面を跨いで存在するため、耐チッピング性や耐欠損性が向上する結果、合金鋼の高速断続切削加工において、すぐれた切削性能を発揮する。 From the results shown in Table 6, the coating tool of the present invention has a multi-layer hard coating layer in which high Al-AlTiN layers and low Al-AlTiN layers are alternately laminated, thereby achieving abrasion resistance and heat resistance. Excellent, and since the hexagonal crystal grains existing in the coating layer are present across the interface between the high Al-AlTiN layer and the low Al-AlTiN layer, the chipping resistance and the fracture resistance are improved as a result. Demonstrates excellent cutting performance in high-speed intermittent cutting of alloy steel.
これに対して、比較例工具は、被覆層中において、高Ａｌ−ＡｌＴｉＮ層に存在する六方晶結晶粒が、低Ａｌ−ＡｌＴｉＮ層との境界面を跨いで存在しないか、あるいは、低Ａｌ−ＡｌＴｉＮ層との境界面を超えて成長するものが少なく、耐欠損性や耐チッピング性に劣るため、チッピングの発生が認められ、比較的短時間で使用寿命に至ることが明らかとなった。 On the other hand, in the comparative example tool, in the coating layer, the hexagonal crystal grains existing in the high Al—AlTiN layer do not exist across the boundary surface with the low Al—AlTiN layer, or the low Al— It was clarified that the occurrence of chipping was observed and the service life was reached in a relatively short time because few of them grew beyond the interface with the AlTiN layer and were inferior in fracture resistance and chipping resistance.
本発明の被覆工具は、高熱発生を伴い、しかも、切刃に対し衝撃的・断続的な高負荷が作用する合金鋼などの高速断続切削加工に供した場合に、すぐれた耐チッピング性とともに長期の使用に亘ってすぐれた耐熱性、耐摩耗性を発揮するものであるから、切削加工装置のＦＡ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。
The covering tool of the present invention has excellent chipping resistance and a long period of time when subjected to high-speed intermittent cutting of alloy steel or the like, which is accompanied by high heat generation and in which a high impact and intermittent high load acts on the cutting edge. Since it exhibits excellent heat resistance and wear resistance throughout its use, it can fully respond to FA conversion of cutting equipment, labor saving and energy saving of cutting processing, and cost reduction. be.
Claims (3)
前記硬質被覆層は、工具基体の表面より、低Ａｌ−ＡｌＴｉＮ層と高Ａｌ−ＡｌＴｉＮ層が交互に積層されてなる２層以上の多層被覆層であり、
（ａ）各層および被覆層全体の組成は、
低Ａｌ−ＡｌＴｉＮ層では、（ＡｌＸＴｉ１−Ｘ）Ｎ ０．５０≦ｘ＜０．７０（ｘは原子比）であり、立方晶組織を主相とし、
高Ａｌ−ＡｌＴｉＮ層では、（ＡｌｙＴｉ１−ｙ）Ｎ ０．７０≦ｙ≦０．９５（ｙは原子比）であり、六方晶組織を主相とし、
被覆層全体では、（ＡｌｚＴｉ１−ｚ）Ｎ ０．６０≦ｚ≦０．８５（ｚは原子比）であり、
（ｂ）各層の平均層厚および全硬質被覆層の平均膜厚は、
各低Ａｌ−ＡｌＴｉＮ層および各高Ａｌ−ＡｌＴｉＮ層では、それぞれ２〜３０ｎｍであり、被覆層全体では、０．５〜８．０μｍであり、
（ｃ）六方晶組織を形成する六方晶結晶粒は、少なくとも一組の高Ａｌ−ＡｌＴｉＮ層と該高Ａｌ−ＡｌＴｉＮ層と隣り合う低Ａｌ−ＡｌＴｉＮ層とに跨って成長しており、その層界面を跨る前記六方晶結晶粒の個数は、界面の単位面積０．０４μｍ２当たり２個以上であって、前記層界面に対する垂直長さが、２〜５０ｎｍであり、前記層界面に対して前記六方晶結晶粒が占める面積率は５％以上であることを特徴とする表面被覆切削工具。 In a surface-coated cutting tool having a hard coating layer on the surface of a tool substrate composed of either a tungsten carbide-based cemented carbide, a titanium nitride-based cermet, or a cubic boron nitride-based ultrahigh-pressure sintered body.
The hard coating layer is two or more multilayer coating layers in which low Al-AlTiN layers and high Al-AlTiN layers are alternately laminated from the surface of the tool substrate.
(A) The composition of each layer and the entire coating layer is
In the low Al—AlTiN layer, (Al X Ti 1-X ) N 0.50 ≦ x <0.70 (x is an atomic ratio), and the cubic structure is the main phase.
In the high Al—AlTiN layer, (Al y Ti 1-y ) N 0.70 ≦ y ≦ 0.95 (y is an atomic ratio), and the hexagonal structure is the main phase.
In the entire coating layer, (Al z Ti 1-z ) N 0.60 ≦ z ≦ 0.85 (z is an atomic ratio).
(B) The average thickness of each layer and the average film thickness of all hard coating layers are
Each low Al-AlTiN layer and each high Al-AlTiN layer is 2 to 30 nm, and the entire coating layer is 0.5 to 8.0 μm.
(C) The hexagonal crystal grains forming the hexagonal structure grow over at least one set of high Al-AlTiN layers and a low Al-AlTiN layer adjacent to the high Al-AlTiN layers, and the layers thereof. the hexagonal grains of the number across the interface, I unit area 0.04 .mu.m 2 per two or more der surfactants, vertical length to layer interface is a 2 to 50 nm, with respect to the layer interface surface-coated cutting tool area ratio where the hexagonal crystal grains occupied, characterized in der Rukoto more than 5%.
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