JP5187573B2 - Surface-coated cutting tool that exhibits excellent chipping resistance and wear resistance with a hard coating layer in high-speed heavy cutting - Google Patents
Surface-coated cutting tool that exhibits excellent chipping resistance and wear resistance with a hard coating layer in high-speed heavy cutting Download PDFInfo
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この発明は、下部層と上部層からなる硬質被覆層を蒸着形成した表面被覆切削工具において、硬質被覆層の上部層として、切刃稜線部にはκ型結晶構造を主体とする酸化アルミニウム（以下、κ型Ａｌ２Ｏ３で示す）層を、また、切刃稜線部以外のすくい面および逃げ面にα型結晶構造を主体とする酸化アルミニウム（以下、α型Ａｌ２Ｏ３で示す）層を蒸着形成することにより、例えば、鋼や鋳鉄の高い発熱を伴い、かつ、切刃に対して高負荷が作用する高速重切削加工に用いた場合にも、硬質被覆層が、すぐれた耐チッピング性と耐摩耗性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 relates to a surface-coated cutting tool in which a hard coating layer composed of a lower layer and an upper layer is formed by vapor deposition. As an upper layer of the hard coating layer, an aluminum oxide (hereinafter referred to as κ-type crystal structure) is mainly used as a cutting blade ridge line portion. the) layer shown in κ-type Al 2 O 3, also aluminum oxide mainly comprising α-type crystal structure on the rake face and the flank face other than the cutting edge ridge line portion (hereinafter, indicated by α-type Al 2 O 3) layer For example, the hard coating layer has excellent chipping resistance even when it is used for high-speed heavy cutting with high heat generation of steel and cast iron and high load acting on the cutting edge. The present invention relates to a surface-coated cutting tool (hereinafter referred to as a coated tool) that exhibits high performance and wear resistance.
従来、炭化タングステン（以下、ＷＣで示す）基超硬合金または炭窒化チタン（以下、ＴｉＣＮで示す）基サーメットで構成された基体（以下、工具基体という）の表面に、
下部層として、Ｔｉの炭化物（以下、ＴｉＣで示す）層、窒化物（以下、同じくＴｉＮで示す）層、炭窒化物（以下、ＴｉＣＮで示す）層、炭酸化物（以下、ＴｉＣＯで示す）層および炭窒酸化物（以下、ＴｉＣＮＯで示す）層のうちの１層または２層以上からなるＴｉ化合物層、
上部層として、酸化アルミニウム（以下、Ａｌ２Ｏ３で示す）層からなり、かつ、すくい面はα型結晶構造を主体とするＡｌ２Ｏ３（以下、α−Ａｌ２Ｏ３で示す）層、また、逃げ面はκ型結晶構造を主体とするＡｌ２Ｏ３（以下、κ−Ａｌ２Ｏ３で示す）層、
上記各層からなる硬質被覆層を蒸着形成した被覆工具（以下、従来被覆工具１という）が知られており、この従来被覆工具１は、逃げ面に形成されたκ−Ａｌ２Ｏ３層表面が平滑性を有するため、例えば仕上切削加工において滑らかな被削面を得られることが知られている。
Conventionally, on the surface of a base body (hereinafter referred to as a tool base body) composed of a tungsten carbide (hereinafter referred to as WC) base cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) base cermet,
As a lower layer, Ti carbide (hereinafter referred to as TiC) layer, nitride (hereinafter also referred to as TiN) layer, carbonitride (hereinafter referred to as TiCN) layer, carbon oxide (hereinafter referred to as TiCO) layer And a Ti compound layer composed of one or more of the carbonitride oxide (hereinafter referred to as TiCNO) layers,
The upper layer is made of an aluminum oxide (hereinafter referred to as Al 2 O 3 ) layer, and the rake face is an Al 2 O 3 (hereinafter referred to as α-Al 2 O 3 ) layer mainly composed of an α-type crystal structure. The flank face is an Al 2 O 3 (hereinafter referred to as κ-Al 2 O 3 ) layer mainly composed of a κ-type crystal structure,
A coated tool (hereinafter referred to as a conventional coated tool 1) in which a hard coating layer composed of each of the above layers is vapor-deposited is known. This conventional coated tool 1 has a surface of a κ-Al 2 O 3 layer formed on a flank. Since it has smoothness, it is known that a smooth cut surface can be obtained, for example, in finish cutting.
また、工具基体という）の表面に、
下部層として、ＴｉＣ層、ＴｉＮ層、ＴｉＣＮ層、ＴｉＣＯ層およびＴｉＣＮＯ層のうちの１層または２層以上からなる改質Ｔｉ化合物層、
上部層として、化学蒸着形成された状態でα型の結晶構造を有する改質α−Ａｌ２Ｏ３層からなり、さらに、上記改質α−Ａｌ２Ｏ３層は、電界放出型走査電子顕微鏡を用い、表面研磨面の測定範囲内に存在する六方晶結晶格子を有する結晶粒個々に電子線を照射して、前記表面研磨面の法線に対して、前記結晶粒の結晶面である（０００１）面の法線がなす傾斜角を測定し、前記測定傾斜角のうち、０〜４５度の範囲内にある測定傾斜角を０．２５度のピッチ毎に区分すると共に、各区分内に存在する度数を集計してなる傾斜角度数分布グラフを作成した場合、上記傾斜角度数分布グラフにおいて０〜１５度の範囲内の傾斜角区分に最高ピークが存在する改質α−Ａｌ２Ｏ３層、
上記各層からなる硬質被覆層を蒸着形成した被覆工具（以下、従来被覆工具２という）も知られており、この従来被覆工具２は、鋼や鋳鉄の切削加工ですぐれた耐チッピング性を発揮することが知られている。
As a lower layer, a modified Ti compound layer composed of one or more of a TiC layer, a TiN layer, a TiCN layer, a TiCO layer, and a TiCNO layer,
The upper layer is composed of a modified α-Al 2 O 3 layer having an α-type crystal structure in a state where chemical vapor deposition is formed, and the modified α-Al 2 O 3 layer is a field emission scanning electron microscope. Is used to irradiate each crystal grain having a hexagonal crystal lattice existing within the measurement range of the surface polished surface with an electron beam, and the crystal plane of the crystal grain with respect to the normal of the surface polished surface ( The tilt angle formed by the normal line of the (0001) plane is measured, and among the measured tilt angles, the measured tilt angles within a range of 0 to 45 degrees are divided into pitches of 0.25 degrees, and within each section When an inclination angle frequency distribution graph obtained by counting the existing frequencies is prepared, the modified α-Al 2 O 3 having the highest peak in the inclination angle section within the range of 0 to 15 degrees in the inclination angle frequency distribution graph. layer,
A coated tool (hereinafter referred to as a conventional coated tool 2) in which a hard coating layer composed of the above layers is formed by vapor deposition is also known, and this conventional coated tool 2 exhibits excellent chipping resistance in cutting of steel or cast iron. It is known.
近年の切削装置の高性能化はめざましく、一方で切削加工に対する省力化および省エネ化、さらに低コスト化の要求は強く、これに伴い、切削加工は一段と高速化・高能率化する傾向にあるが、上記従来の被覆工具においては、これを鋼や鋳鉄などの通常の条件での連続切削や断続切削に用いた場合には問題はないが、特にこれを高熱発生を伴い、かつ、切刃に対して高負荷が作用する高速重切削加工で用いた場合には、例えば、従来被覆工具１においては、切刃稜線部のすくい面側から、α−Ａｌ２Ｏ３部にチッピングが発生しやすくなるとともに、逃げ面のκ型Ａｌ２Ｏ３層の摩耗が急速に進行するようになり、また、従来被覆工具２においても、切刃稜線部の耐チッピング性が不十分であるため、比較的短時間で使用寿命に至るのが現状である。 In recent years, the performance of cutting machines has been remarkable. On the other hand, there is a strong demand for labor saving, energy saving, and cost reduction for cutting work, and along with this, cutting work tends to become even faster and more efficient. In the above-mentioned conventional coated tool, there is no problem when it is used for continuous cutting or interrupted cutting under normal conditions such as steel or cast iron. On the other hand, when used in high-speed heavy cutting where a high load acts, for example, in the conventional coated tool 1, chipping is likely to occur in the α-Al 2 O 3 part from the rake face side of the cutting edge ridge line part. At the same time, wear of the κ-type Al 2 O 3 layer on the flank surface proceeds rapidly, and in the conventional coated tool 2 as well, the chipping resistance of the cutting edge ridge is insufficient. The service life is reached in a short time Currently.
そこで、本発明者等は、上述のような観点から、特に高熱発生を伴い、かつ、切刃に対して高負荷が作用する高速重切削条件における硬質被覆層の耐チッピング性、耐摩耗性をさらに改善すべく研究を行った結果、以下の知見を得た。 In view of the above, the inventors of the present invention have the chipping resistance and wear resistance of the hard coating layer under high-speed heavy cutting conditions that are accompanied by particularly high heat generation and a high load acts on the cutting edge. As a result of research to further improve, the following knowledge was obtained.
（ａ）上記従来の被覆工具の硬質被覆層の上部層を構成するα−Ａｌ２Ｏ３層は、基体表面に、ＴｉＣ層、ＴｉＮ層、ＴｉＣＮ層、ＴｉＣＯ層、ＴｉＮＯ層およびＴｉＣＮＯ層のうちの１層または２層以上のＴｉ化合物層からなる下部層を所定条件で蒸着形成した後、その表面に、例えば、通常の化学蒸着装置にて、
反応ガス組成：容量％で、ＡｌＣｌ3：１〜５％、ＣＯ2：３〜７％、ＨＣｌ：０．３〜３％、Ｈ2Ｓ：０．０２〜０．４％、Ｈ2：残り、
反応雰囲気温度：９５０〜１１００℃、
反応雰囲気圧力：６〜１３ｋＰａ、
の条件で蒸着することによって形成される（上記の蒸着条件を、以下、通常条件という）。しかし、下部層表面に上部層であるα−Ａｌ2Ｏ3層を蒸着する前に、例えば、表３に示される条件にてＴｉ酸化物（以下、ＴｉＯで示す）層を蒸着形成し、その後特定の条件で還元処理を施した場合には、切刃稜線部の形状特異性により、工具の切刃稜線部はその他の領域に比して優先的に還元反応が促進されることになり、さらに、上記ＴｉＯ層蒸着後に還元処理を施した下部層表面に、例えば、上記通常条件でＡｌ２Ｏ３層を蒸着すると、切刃稜線部以外の領域には、α型結晶構造を主体とするＡｌ２Ｏ３（以下、α型Ａｌ２Ｏ３で示す）層が蒸着形成されるが、切刃稜線部にはκ型結晶構造を主体とするＡｌ２Ｏ３（以下、κ型Ａｌ２Ｏ３で示す）層が蒸着形成される。そして、κ型Ａｌ２Ｏ３層はα型Ａｌ２Ｏ３層に比してすぐれた熱遮蔽性を有し、熱塑性変形を起こりにくくすると同時に、表面平滑性を有しチッピングの発生を抑える。
したがって、切刃稜線部にκ型Ａｌ２Ｏ３層が形成され、また、切刃稜線部以外の領域（すくい面および逃げ面）に上記α型Ａｌ２Ｏ３層が形成された被覆工具は、高熱発生を伴い、かつ、切刃に対して高負荷が作用する高速重切削加工で、すくい面および逃げ面がすぐれた耐摩耗性を示すと同時に、切刃稜線部の耐熱塑性変形性および耐チッピング性が一段と向上すること。
(A) The α-Al 2 O 3 layer that constitutes the upper layer of the hard coating layer of the conventional coated tool is formed of a TiC layer, a TiN layer, a TiCN layer, a TiCO layer, a TiNO layer, and a TiCNO layer on the substrate surface. After forming a lower layer composed of one or two or more Ti compound layers under a predetermined condition, on the surface thereof, for example, with a normal chemical vapor deposition apparatus,
Reaction gas composition: by volume%, AlCl 3: 1~5%, CO 2: 3~7%, HCl: 0.3~3%, H 2 S: 0.02~0.4%, H 2: remainder ,
Reaction atmosphere temperature: 950-1100 ° C.
Reaction atmosphere pressure: 6-13 kPa,
(The above vapor deposition conditions are hereinafter referred to as normal conditions). However, before depositing the α-Al 2 O 3 layer, which is the upper layer, on the surface of the lower layer, for example, a Ti oxide (hereinafter referred to as TiO) layer is formed by vapor deposition under the conditions shown in Table 3, and thereafter When the reduction process is performed under specific conditions, due to the shape specificity of the cutting edge ridge line, the cutting edge ridge line of the tool will be promoted preferentially over other regions, Further, when, for example, an Al 2 O 3 layer is deposited on the surface of the lower layer subjected to the reduction treatment after the TiO layer deposition, the region other than the cutting edge ridge is mainly composed of an α-type crystal structure. An Al 2 O 3 (hereinafter referred to as α-type Al 2 O 3 ) layer is formed by vapor deposition. Al 2 O 3 (hereinafter referred to as κ-type Al 2 O) mainly composed of a κ-type crystal structure is formed at the edge of the cutting edge. 3 ) is deposited. The κ-type Al 2 O 3 layer has excellent heat shielding properties as compared with the α-type Al 2 O 3 layer, makes it difficult to cause thermoplastic deformation, and has surface smoothness to suppress the occurrence of chipping.
Therefore, the coated tool in which the κ-type Al 2 O 3 layer is formed on the cutting edge ridge line, and the α-type Al 2 O 3 layer is formed in a region other than the cutting edge ridge line (rake face and flank) High-speed heavy cutting with high heat generation and high load acting on the cutting edge, with excellent wear resistance on the rake face and flank surface, and at the same time, heat-resistant plastic deformation and Chipping resistance is further improved.
（ｂ）また、Ａｌ２Ｏ３層を蒸着する上記通常条件において、反応ガス組成、反応雰囲気温度および反応雰囲気圧力を変更し、
反応ガス組成：容量％で、ＡｌＣｌ3：１〜５％、ＣＯ2：０．１〜２％、ＨＣｌ：０．３〜３％、Ｈ2Ｓ：０．５〜１％、Ａｒ：２０〜３５％、Ｈ2：残り、
反応雰囲気温度：１０５０〜１１００℃、
反応雰囲気圧力：６〜１０ｋＰａ、
という条件（以下、改質条件という）で、Ａｌ２Ｏ３層を蒸着すると、切刃稜線部にはκ型Ａｌ２Ｏ３層が蒸着形成されることは前記と同様であるが、切刃稜線部以外の領域（すくい面および逃げ面）に蒸着形成されたα型Ａｌ２Ｏ３層について、図１に示すように、電界放出型走査電子顕微鏡を用い、表面研磨面の測定範囲内に存在する六方晶結晶格子を有する結晶粒個々に電子線を照射して、前記表面研磨面の法線に対して、前記結晶粒の結晶面である（０００１）面の法線がなす傾斜角を測定し、前記測定傾斜角のうち、０〜４５度の範囲内にある測定傾斜角を０．２５度のピッチ毎に区分すると共に、各区分内に存在する度数を集計してなる傾斜角度数分布グラフを作成した場合、上記傾斜角度数分布グラフにおいて０〜１５度の範囲内の傾斜角区分に最高ピークが存在するα型Ａｌ２Ｏ３層（以下、改質α型Ａｌ２Ｏ３層という）が形成され、上記改質α型Ａｌ２Ｏ３層は、α型Ａｌ２Ｏ３層に比して、一段とすぐれた耐チッピング性を有する。
したがって、硬質被覆層の上部層として、切刃稜線部にκ型Ａｌ２Ｏ３層が形成され、また、切刃稜線部以外の領域（すくい面および逃げ面）に上記改質α型Ａｌ２Ｏ３層が形成された被覆工具は、高熱発生を伴い、かつ、切刃に対して高負荷が作用する高速重切削加工ですぐれた耐チッピング性、耐熱塑性変形性およびすぐれた耐摩耗性を示すこと。
(B) In the above normal conditions for depositing the Al 2 O 3 layer, the reaction gas composition, the reaction atmosphere temperature and the reaction atmosphere pressure are changed,
Reaction gas composition: by volume%, AlCl 3: 1~5%, CO 2: 0.1~2%, HCl: 0.3~3%, H 2 S: 0.5~1%, Ar: 20~ 35%, H 2 : remaining,
Reaction atmosphere temperature: 1050 to 1100 ° C.
Reaction atmosphere pressure: 6 to 10 kPa,
When the Al 2 O 3 layer is vapor-deposited under the above conditions (hereinafter referred to as reforming conditions), the κ-type Al 2 O 3 layer is vapor-deposited on the cutting edge ridge, as described above. With respect to the α-type Al 2 O 3 layer formed by vapor deposition on the region other than the ridge line portion (rake face and flank face), as shown in FIG. 1, using a field emission scanning electron microscope, within the measurement range of the surface polished surface By irradiating each crystal grain having a hexagonal crystal lattice with an electron beam, an inclination angle formed by a normal line of the (0001) plane which is a crystal plane of the crystal grain with respect to a normal line of the surface polished surface is set. Measured and divided the measured inclination angle within the range of 0 to 45 degrees among the measured inclination angles for each pitch of 0.25 degrees, and the number of inclination angles obtained by totalizing the frequencies existing in each section When a distribution graph is created, 0 to 15 degrees in the above inclination angle number distribution graph An α-type Al 2 O 3 layer (hereinafter referred to as a modified α-type Al 2 O 3 layer) having the highest peak in the inclination angle section within the range of is formed, and the modified α-type Al 2 O 3 layer is Compared to the α-type Al 2 O 3 layer, it has excellent chipping resistance.
Therefore, as the upper layer of the hard coating layer, a κ-type Al 2 O 3 layer is formed on the cutting edge ridge line portion, and the modified α-type Al 2 is formed in a region (rake face and flank face) other than the cutting edge ridge line portion. The coated tool with the O 3 layer has high heat generation and has excellent chipping resistance, heat plastic deformation resistance and excellent wear resistance in high speed heavy cutting with high load acting on the cutting edge. Showing.
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または炭窒化チタン基サーメットで構成された工具基体の表面に、硬質被覆層として、Ｔｉの炭化物層、窒化物層、炭窒化物層、炭酸化物層、窒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、かつ３〜２０μｍの合計平均層厚を有するＴｉ化合物層からなる下部層及び１〜１５μｍの平均層厚を有する酸化アルミニウム層からなる上部層を蒸着形成した表面被覆切削工具において、
上記表面被覆切削工具の切刃稜線部に蒸着形成された上部層はκ型結晶構造を主体とする酸化アルミニウム層からなり、一方、前記切刃稜線部以外のすくい面および逃げ面に蒸着形成された上部層は実質的にα型結晶構造を主体とする酸化アルミニウム層からなることを特徴とする表面被覆切削工具。
（２） 前記（１）記載の表面被覆切削工具において、
上記α型結晶構造を主体とする酸化アルミニウム層について、電界放出型走査電子顕微鏡を用い、表面研磨面の測定範囲内に存在する六方晶結晶格子を有する結晶粒個々に電子線を照射して、前記表面研磨面の法線に対して、前記結晶粒の結晶面である（０００１）面の法線がなす傾斜角を測定し、前記測定傾斜角のうち、０〜４５度の範囲内にある測定傾斜角を０．２５度のピッチ毎に区分すると共に、各区分内に存在する度数を集計してなる傾斜角度数分布グラフを作成した場合、上記α型結晶構造を主体とする酸化アルミニウム層は、上記傾斜角度数分布グラフにおいて０〜１５度の範囲内の傾斜角区分に最高ピークが存在する酸化アルミニウム層である前記（１）記載の表面被覆切削工具。」
に特徴を有するものである。
This invention has been made based on the above findings,
“(1) As a hard coating layer, a Ti carbide layer, nitride layer, carbonitride layer, carbon dioxide layer, nitrogen nitride is applied as a hard coating layer to the surface of a tool base composed of tungsten carbide-based cemented carbide or titanium carbonitride-based cermet. A lower layer made of a Ti compound layer having a total average layer thickness of 3 to 20 μm, and an oxidation having an average layer thickness of 1 to 15 μm, consisting of one or more of an oxide layer and a carbonitride oxide layer In a surface-coated cutting tool in which an upper layer made of an aluminum layer is formed by vapor deposition,
The upper layer formed by vapor deposition on the cutting edge ridge portion of the surface-coated cutting tool is composed of an aluminum oxide layer mainly composed of a κ-type crystal structure, while being formed by vapor deposition on the rake face and flank other than the cutting edge ridge line portion. A surface-coated cutting tool characterized in that the upper layer substantially comprises an aluminum oxide layer mainly composed of an α-type crystal structure.
(2) In the surface-coated cutting tool according to (1),
For the aluminum oxide layer mainly composed of the α-type crystal structure, a field emission scanning electron microscope is used to irradiate the individual crystal grains having a hexagonal crystal lattice existing in the measurement range of the surface polished surface with an electron beam, The inclination angle formed by the normal line of the (0001) plane, which is the crystal plane of the crystal grain, is measured with respect to the normal line of the surface-polished surface, and is within the range of 0 to 45 degrees out of the measured inclination angle. When the measurement inclination angle is divided into pitches of 0.25 degrees, and an inclination angle number distribution graph is formed by summing up the frequencies existing in each division, the aluminum oxide layer mainly composed of the α-type crystal structure. Is a surface-coated cutting tool according to the above (1), which is an aluminum oxide layer in which the highest peak exists in the inclination angle section within the range of 0 to 15 degrees in the inclination angle number distribution graph. "
It has the characteristics.
以下に、この発明の被覆工具の硬質被覆層の構成層に関し、詳細に説明する。 Below, it demonstrates in detail regarding the structural layer of the hard coating layer of the coating tool of this invention.
（ａ）Ｔｉ化合物層(下部層)
Ｔｉ化合物層は、基本的には上部層であるＡｌ２Ｏ３層の下部層として存在し、自身の具備するすぐれた高温強度によって硬質被覆層が高温強度を具備するようにするほか、工具基体と上部層であるＡｌ２Ｏ３層のいずれにも強固に密着し、よって硬質被覆層の工具基体に対する密着性向上に寄与する作用を有するが、その平均層厚が３μｍ未満では、前記作用を十分に発揮させることができず、一方その平均層厚が２０μｍを越えると、特に高熱発生を伴い、かつ、切刃に対して高負荷が作用する高速重切削では熱塑性変形を起し易くなり、これが偏摩耗の原因となることから、その平均層厚を３〜２０μｍと定めた。
(A) Ti compound layer (lower layer)
The Ti compound layer basically exists as a lower layer of the Al 2 O 3 layer, which is the upper layer, and allows the hard coating layer to have a high temperature strength due to its excellent high temperature strength. And the upper layer Al 2 O 3 layer firmly adhere to each other, and thus has an effect of improving the adhesion of the hard coating layer to the tool substrate, but when the average layer thickness is less than 3 μm, On the other hand, when the average layer thickness exceeds 20 μm, it is particularly likely to cause thermoplastic deformation in high-speed heavy cutting with high heat generation and high load acting on the cutting edge. Since this causes uneven wear, the average layer thickness was determined to be 3 to 20 μm.
（ｂ）α型Ａｌ２Ｏ３層（上部層）
被覆工具の切刃稜線部以外の領域、即ち、すくい面および逃げ面、に、通常条件でＡｌ２Ｏ３層を蒸着することによって形成されるが、κ型Ａｌ２Ｏ３層に比して、相対的に高温硬さおよび耐熱性に優れることから、被覆工具のすくい面および逃げ面（即ち、切刃稜線部以外の領域）に蒸着形成することによって、被覆工具全体としてのすぐれた耐摩耗性が担保される。
(B) α-type Al 2 O 3 layer (upper layer)
It is formed by vapor-depositing an Al 2 O 3 layer under normal conditions in a region other than the cutting edge ridge line portion of the coated tool, that is, a rake face and a flank face, but compared with a κ-type Al 2 O 3 layer. Since it is relatively excellent in high-temperature hardness and heat resistance, it has excellent wear resistance as a whole coated tool by vapor deposition on the rake face and flank face of the coated tool (that is, the region other than the cutting edge ridge). Sex is guaranteed.
（ｃ）改質α型Ａｌ２Ｏ３層（上部層）
通常条件で蒸着形成した上記α型Ａｌ２Ｏ３層は耐摩耗性に優れるが、蒸着条件を、
反応ガス組成：容量％で、ＡｌＣｌ3：１〜５％、ＣＯ2：０．１〜２％、ＨＣｌ：０．３〜３％、Ｈ2Ｓ：０．５〜１％、Ａｒ：２０〜３５％、Ｈ2：残り、
反応雰囲気温度：１０５０〜１１００℃、
反応雰囲気圧力：６〜１０ｋＰａ、
という改質条件、即ち、通常条件に比して、反応ガス組成、反応雰囲気温度、反応雰囲気圧力を変更した蒸着条件によって、傾斜角度数分布グラフにおける測定傾斜角の最高ピーク位置が、０〜１５度の範囲内の傾斜角区分に存在する改質α型Ａｌ２Ｏ３層を蒸着形成することができる。
つまり、図１に示すように、上記改質条件により蒸着形成した改質α型Ａｌ２Ｏ３層について、電界放出型走査電子顕微鏡を用い、表面研磨面の測定範囲内に存在する六方晶結晶格子を有する結晶粒個々に電子線を照射して、前記表面研磨面の法線に対して、前記結晶粒の結晶面である（０００１）面の法線がなす傾斜角を測定し、前記測定傾斜角のうち、０〜４５度の範囲内にある測定傾斜角を０．２５度のピッチ毎に区分すると共に、各区分内に存在する度数を集計してなる傾斜角度数分布グラフを作成した場合、上記改質α型Ａｌ２Ｏ３層は、例えば、図２に示されるように、上記傾斜角度数分布グラフにおいて０〜１５度の範囲内の傾斜角区分に最高ピークが存在する。
そして、上記改質α型Ａｌ２Ｏ３層は、前記通常条件で形成したα型Ａｌ２Ｏ３層に比べ、さらに一段とすぐれた高温硬さを有することから、すくい面および逃げ面に改質α型Ａｌ２Ｏ３層が蒸着形成された被覆工具（請求項２の発明）はさらに一段とすぐれた耐摩耗性を示す。
(C) Modified α-type Al 2 O 3 layer (upper layer)
The α-type Al 2 O 3 layer formed by vapor deposition under normal conditions is excellent in wear resistance.
Reaction gas composition: by volume%, AlCl 3: 1~5%, CO 2: 0.1~2%, HCl: 0.3~3%, H 2 S: 0.5~1%, Ar: 20~ 35%, H 2 : remaining,
Reaction atmosphere temperature: 1050 to 1100 ° C.
Reaction atmosphere pressure: 6 to 10 kPa,
The maximum peak position of the measured tilt angle in the tilt angle number distribution graph is 0 to 15 depending on the deposition conditions in which the reaction gas composition, the reaction atmosphere temperature, and the reaction atmosphere pressure are changed as compared with the normal conditions, i.e., the normal conditions. The modified α-type Al 2 O 3 layer existing in the tilt angle section within the range of degrees can be formed by vapor deposition.
That is, as shown in FIG. 1, a hexagonal crystal existing within the measurement range of the surface polished surface is obtained using a field emission scanning electron microscope for the modified α-type Al 2 O 3 layer formed by vapor deposition under the above-described modification conditions. By irradiating each crystal grain having a lattice with an electron beam, an inclination angle formed by a normal line of the (0001) plane which is a crystal plane of the crystal grain is measured with respect to a normal line of the surface polished surface, and the measurement is performed. Among the inclination angles, the measurement inclination angle within the range of 0 to 45 degrees is divided for each pitch of 0.25 degrees, and an inclination angle number distribution graph is created by counting the frequencies existing in each division. In this case, the modified α-type Al 2 O 3 layer has, for example, the highest peak in the tilt angle section within the range of 0 to 15 degrees in the tilt angle number distribution graph, as shown in FIG.
The modified α-type Al 2 O 3 layer has a higher temperature hardness than that of the α-type Al 2 O 3 layer formed under the normal conditions. The coated tool in which the α-type Al 2 O 3 layer is formed by vapor deposition (invention of claim 2) further exhibits excellent wear resistance.
（ｄ）κ型Ａｌ２Ｏ３層（上部層）
κ型Ａｌ２Ｏ３層は、α型Ａｌ２Ｏ３層あるいは改質α型Ａｌ２Ｏ３層に比して、平滑性、熱遮蔽性にすぐれているため、被削材の仕上面粗さを向上させるばかりか、被覆工具の耐熱塑性変形性、耐チッピング性を向上させ、特に、高速重切削においては、最も切削負荷のかかる切刃稜線部にκ型Ａｌ２Ｏ３層を形成することによって、被覆工具の耐摩耗性を特段低下させることなく耐チッピング性を大幅に向上させることができる。
(D) κ-type Al 2 O 3 layer (upper layer)
The κ-type Al 2 O 3 layer is superior to the α-type Al 2 O 3 layer or the modified α-type Al 2 O 3 layer in terms of smoothness and heat shielding properties. In addition to improving the heat resistance plastic deformation resistance and chipping resistance of the coated tool, especially in high-speed heavy cutting, a κ-type Al 2 O 3 layer is formed on the edge of the cutting edge where the most cutting load is applied. Thus, the chipping resistance can be significantly improved without particularly reducing the wear resistance of the coated tool.
κ型Ａｌ２Ｏ３層を切刃稜線部に蒸着形成させる方法は、例えば、以下の手順で行なうことができる。
まず、工具基体表面の少なくとも切刃稜線部を含む領域に、下部層のＴｉ化合物層として例えば所定層厚のＴｉＣＮＯ層を蒸着形成した後、ＴｉＣＮＯ層の表面に、極薄（例えば、０．１〜０．５μｍの層厚）のＴｉＯ層を蒸着形成する。
ついで、ＴｉＣＮＯ層の表面に形成された極薄のＴｉＯ層を、
反応雰囲気ガス組成（容量％）：ＣＨ４ ０．３〜０．８％、残部Ｈ２
反応雰囲気温度：９００〜１０００℃、
反応雰囲気圧力：３〜８ｋＰａ、
の条件で還元処理すると、切刃稜線部のＴｉＯ層は、他の領域のＴｉＯ層と比べて優先的に還元処理されてＴｉＣが形成される。
その後、通常条件でα型Ａｌ２Ｏ３層を蒸着形成、あるいは、改質条件で改質α型Ａｌ２Ｏ３層を蒸着形成すると、優先的にＴｉＣが形成された切刃稜線部には、κ型Ａｌ２Ｏ３層が形成され、その一方、切刃稜線部以外の領域（すくい面および逃げ面）には、その条件に応じたα型Ａｌ２Ｏ３層あるいは改質α型Ａｌ２Ｏ３層が蒸着形成され、その結果、切刃稜線部のみにκ型結晶構造を主体とする酸化アルミニウム層からなる上部層が、また、切刃稜線部以外のすくい面および逃げ面にα型結晶構造を主体とする酸化アルミニウム層からなる上部層が蒸着された被覆工具が形成される。
The method of vapor-depositing the κ-type Al 2 O 3 layer on the cutting edge ridge line portion can be performed, for example, by the following procedure.
First, after depositing, for example, a TiCNO layer having a predetermined thickness as a lower Ti compound layer in a region including at least the cutting edge ridge line portion on the surface of the tool base, an ultrathin (for example, 0.1 A TiO layer having a thickness of ˜0.5 μm is deposited.
Then, an ultrathin TiO layer formed on the surface of the TiCNO layer,
Reaction atmosphere gas composition (volume%): CH 4 0.3 to 0.8%, balance H 2
Reaction atmosphere temperature: 900-1000 ° C.
Reaction atmosphere pressure: 3 to 8 kPa,
When the reduction treatment is performed under the conditions, the TiO layer in the cutting edge ridge line portion is preferentially reduced as compared with the TiO layers in other regions, and TiC is formed.
After that, when the α-type Al 2 O 3 layer is vapor-deposited under normal conditions, or when the modified α-type Al 2 O 3 layer is vapor-deposited under the reforming conditions, the cutting edge ridge line where TiC is preferentially formed is formed. , And a κ-type Al 2 O 3 layer is formed. On the other hand, a region other than the cutting edge ridge line portion (rake face and flank face) is an α-type Al 2 O 3 layer or a modified α-type Al depending on the conditions. 2 O 3 layer is deposited formed, as a result, the upper layer made of aluminum oxide layer mainly comprising κ-type crystal structure only the cutting edge ridge line portion is also, alpha to the rake face and the flank face other than the cutting edge ridge A coated tool is formed on which an upper layer composed of an aluminum oxide layer mainly composed of a mold crystal structure is deposited.
なお、本発明では、「α型結晶構造を主体とする酸化アルミニウム層」あるいは「α型Ａｌ２Ｏ３層」とは、α型結晶構造が１００％を占める場合は勿論であるが、全体の中で、少なくとも８０％以上がα型結晶構造の酸化アルミニウムで構成されている場合に、これを「α型結晶構造を主体とする酸化アルミニウム層」あるいは「α型Ａｌ２Ｏ３層」という。同様に、「κ型結晶構造を主体とする酸化アルミニウム層」あるいは「κ型Ａｌ２Ｏ３層」についても、全体の中で、少なくとも８０％以上がκ型結晶構造の酸化アルミニウムで構成されている場合には、これを「κ型結晶構造を主体とする酸化アルミニウム層」あるいは「κ型Ａｌ２Ｏ３層」という。 In the present invention, “aluminum oxide layer mainly composed of α-type crystal structure” or “α-type Al 2 O 3 layer” means that the α-type crystal structure occupies 100%. Among them, when at least 80% or more is composed of aluminum oxide having an α-type crystal structure, this is referred to as “aluminum oxide layer mainly composed of α-type crystal structure” or “α-type Al 2 O 3 layer”. Similarly, at least 80% or more of “aluminum oxide layer mainly composed of κ-type crystal structure” or “κ-type Al 2 O 3 layer” is composed of aluminum oxide having a κ-type crystal structure. In this case, this is called “aluminum oxide layer mainly composed of κ-type crystal structure” or “κ-type Al 2 O 3 layer”.
（ｅ）上部層の層厚
α型Ａｌ２Ｏ３層、κ型Ａｌ２Ｏ３層からなる上部層は、その平均層厚が１μｍ未満では、すくい面、逃げ面におけるα型Ａｌ２Ｏ３層の耐摩耗性向上効果、切刃稜線部におけるκ型Ａｌ２Ｏ３層の熱遮蔽効果、耐チッピング性向上効果を十分に確保することができず、一方、その平均層厚が１５μｍを越えると、チッピング、欠損等が発生し易くなることから、その平均層厚を１〜１５μｍと定めた。
(E) Layer thickness of upper layer The upper layer composed of an α-type Al 2 O 3 layer and a κ-type Al 2 O 3 layer has an average layer thickness of less than 1 μm, and α-type Al 2 O 3 on the rake face and flank face. The effect of improving the wear resistance of the layer, the heat shielding effect of the κ-type Al 2 O 3 layer at the edge of the cutting edge, and the effect of improving the chipping resistance cannot be sufficiently ensured, while the average layer thickness exceeds 15 μm. Then, since chipping, defects, etc. are likely to occur, the average layer thickness is set to 1 to 15 μm.
なお、被覆工具の使用前後の識別を目的として、黄金色の色調を有するＴｉＮ層を、必要に応じて硬質被覆層の最表面層として蒸着形成してもよいが、この場合の平均層厚は０．１〜１μｍでよく、これは０．１μｍ未満では、十分な識別効果が得られず、一方前記ＴｉＮ層による前記識別効果は１μｍまでの平均層厚で十分であるという理由からである。 In addition, for the purpose of identification before and after the use of the coated tool, a TiN layer having a golden color tone may be vapor-deposited as the outermost surface layer of the hard coating layer as necessary, but the average layer thickness in this case is It may be 0.1 to 1 μm, and if the thickness is less than 0.1 μm, a sufficient discrimination effect cannot be obtained, while the discrimination effect by the TiN layer is sufficient for an average layer thickness of up to 1 μm.
この発明の被覆工具は、各種の鋼や鋳鉄などの切削加工を、高熱発生を伴うとともに、切刃に対して高負荷が作用する高速重切削条件で行っても、硬質被覆層の上部層の切刃稜線部をκ型Ａｌ２Ｏ３層で、また、切刃稜線部以外のすくい面、逃げ面の上部層をα型Ａｌ２Ｏ３層、改質α型Ａｌ２Ｏ３層で構成することによって、耐摩耗性の低下を招くことなく耐チッピング性を改善したものであって、使用寿命の一層の延命化を可能とするものである。 The coated tool of this invention is capable of cutting various types of steel and cast iron under high-speed heavy cutting conditions in which a high load is applied to the cutting blade while generating high heat. The cutting edge ridge line part is composed of κ-type Al 2 O 3 layer, and the rake face other than the cutting edge ridge line part and the upper layer of the flank face are composed of α-type Al 2 O 3 layer and modified α-type Al 2 O 3 layer By doing so, the chipping resistance is improved without causing a decrease in wear resistance, and the service life can be further extended.
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。 Next, the coated tool of the present invention will be specifically described with reference to examples.
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、ＶＣ粉末、ＴａＣ粉末、ＮｂＣ粉末、Ｃｒ3 Ｃ2 粉末、ＴｉＮ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、切刃部にＲ：０．０７ｍｍのホーニング加工を施すことによりＩＳＯ・ＣＮＭＧ１２０４０８に規定するスローアウエイチップ形状をもったＷＣ基超硬合金製の工具基体Ａ〜Ｆをそれぞれ製造した。 As raw material powders, WC powder, TiC powder, ZrC powder, VC powder, TaC powder, NbC powder, Cr 3 C 2 powder, TiN powder, and Co powder each having an average particle diameter of 1 to 3 μm are prepared. The raw material powder is blended in the blending composition shown in Table 1, added with wax, ball mill mixed in acetone for 24 hours, dried under reduced pressure, and press-molded into a green compact of a predetermined shape at a pressure of 98 MPa. The green compact is vacuum-sintered in a vacuum of 5 Pa at a predetermined temperature within a range of 1370 to 1470 ° C. for 1 hour. After sintering, the cutting edge is subjected to a honing process of R: 0.07 mm. Thus, tool bases A to F made of a WC-based cemented carbide having a throwaway tip shape specified in ISO · CNMG120408 were manufactured.
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、Ｍｏ2 Ｃ粉末、ＺｒＣ粉末、ＮｂＣ粉末、ＴａＣ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：１５４０℃に１時間保持の条件で焼結し、焼結後、切刃部分にＲ：０．０７ｍｍのホーニング加工を施すことによりＩＳＯ規格・ＣＮＭＧ１２０４１２のチップ形状をもったＴｉＣＮ基サーメット製の工具基体ａ〜ｆを形成した。 In addition, as raw material powders, TiCN (mass ratio TiC / TiN = 50/50) powder, Mo 2 C powder, ZrC powder, NbC powder, TaC powder, WC powder, all having an average particle diameter of 0.5 to 2 μm. Co powder and Ni powder are prepared, and these raw material powders are blended in the blending composition shown in Table 2, wet mixed by a ball mill for 24 hours, dried, and pressed into a compact at a pressure of 98 MPa. The green compact was sintered in a nitrogen atmosphere of 1.3 kPa at a temperature of 1540 ° C. for 1 hour, and after the sintering, the cutting edge portion was subjected to a honing process of R: 0.07 mm. Tool bases a to f made of TiCN-based cermet having a standard / CNMG12041 chip shape were formed.
ついで、これらの工具基体Ａ〜Ｆおよび工具基体ａ〜ｆのそれぞれを、通常の化学蒸着装置に装入し、
まず、表３（表３中のｌ−ＴｉＣＮは特開平６−８０１０号公報に記載される縦長成長結晶組織をもつＴｉＣＮ層の形成条件を示すものであり、これ以外は通常の粒状結晶組織の形成条件を示すものである）に示される条件にて、表５に示される目標層厚のＴｉ化合物層を硬質被覆層の下部層として蒸着形成し、
ついで、同じく表３に示されるＴｉＯ層を表５に示される目標層厚で蒸着形成し、その後、表４に示される条件で還元処理を施し、
ついで、表３に示される条件にて、同じく表５に示される目標層厚でα型Ａｌ２Ｏ３層または改質α型Ａｌ２Ｏ３層を蒸着形成することにより本発明被覆工具１〜１３をそれぞれ製造した。
Then, each of these tool bases A to F and tool bases a to f is charged into a normal chemical vapor deposition apparatus,
First, Table 3 (l-TiCN in Table 3 indicates the conditions for forming a TiCN layer having a vertically grown crystal structure described in JP-A No. 6-8010, and other than that, a normal granular crystal structure is shown. The Ti compound layer having the target layer thickness shown in Table 5 is deposited as a lower layer of the hard coating layer under the conditions shown in FIG.
Next, a TiO layer similarly shown in Table 3 is formed by vapor deposition with a target layer thickness shown in Table 5, and then subjected to a reduction treatment under the conditions shown in Table 4,
Then, under the conditions shown in Table 3, the α-type Al 2 O 3 layer or the modified α-type Al 2 O 3 layer is vapor-deposited with the target layer thickness shown in Table 5 to form the coated tool 1 to 1 of the present invention. 13 were produced respectively.
また、比較の目的で、表３に示される条件にて、表６に示される目標層厚のＴｉ化合物層を硬質被覆層の下部層として蒸着形成し、その後、ＴｉＯ層の蒸着形成および還元処理を施さずに、表３に示される条件にて、表６に示される目標層厚でα型Ａｌ２Ｏ３層、改質α型Ａｌ２Ｏ３層またはκ型Ａｌ２Ｏ３層を蒸着形成することにより、比較被覆工具１〜１３をそれぞれ製造した。 For comparison purposes, a Ti compound layer having the target layer thickness shown in Table 6 is formed as a lower layer of the hard coating layer under the conditions shown in Table 3, and then the TiO layer is formed and reduced. Without depositing, an α-type Al 2 O 3 layer, a modified α-type Al 2 O 3 layer or a κ-type Al 2 O 3 layer is deposited under the conditions shown in Table 3 with the target layer thickness shown in Table 6. By forming, comparative coated tools 1 to 13 were produced, respectively.
ついで、上記の本発明被覆工具１〜１３と比較被覆工具１〜１３のうちの、硬質被覆層の上部層として改質α型Ａｌ２Ｏ３層を蒸着形成した被覆工具について、電界放出型走査電子顕微鏡を用いて、傾斜角度数分布グラフをそれぞれ作成した。
すなわち、上記傾斜角度数分布グラフは、上記の改質α型Ａｌ２Ｏ３層について、表面研磨面とした状態で、電界放出型走査電子顕微鏡の鏡筒内にセットし、前記研磨面に７０度の入射角度で１５ｋＶの加速電圧の電子線を１ｎＡの照射電流で、それぞれの前記研磨面の測定範囲内に存在する六方晶結晶格子を有する結晶粒個々に照射して、電子後方散乱回折像装置を用い、３０×５０μｍの領域を０．１μｍ／ｓｔｅｐの間隔で、前記研磨面の法線に対して、前記結晶粒の結晶面である（０００１）面の法線がなす傾斜角を測定し、この測定結果に基づいて、前記測定傾斜角のうち、０〜４５度の範囲内にある測定傾斜角を０．２５度のピッチ毎に区分すると共に、各区分内に存在する度数を集計することにより作成した。
Next, of the above-described coated tools 1 to 13 and comparative coated tools 1 to 13 described above, the field emission scanning is performed on the coated tool in which the modified α-type Al 2 O 3 layer is deposited as the upper layer of the hard coating layer. An inclination angle number distribution graph was created using an electron microscope.
That is, the inclination angle number distribution graph is set in a lens barrel of a field emission scanning electron microscope with the modified α-type Al 2 O 3 layer as a surface polished surface, and the polished surface has 70 An electron backscattered diffraction image is obtained by irradiating an electron beam with an acceleration voltage of 15 kV at an incident angle of 15 degrees with an irradiation current of 1 nA on each crystal grain having a hexagonal crystal lattice existing in the measurement range of each polished surface. Using an apparatus, the inclination angle formed by the normal of the (0001) plane, which is the crystal plane of the crystal grain, is measured with respect to the normal of the polished surface in a 30 × 50 μm region at an interval of 0.1 μm / step. Based on the measurement results, the measurement inclination angles within the range of 0 to 45 degrees out of the measurement inclination angles are divided for each pitch of 0.25 degrees, and the frequencies existing in each division are tabulated. Created by.
この結果得られた改質α型Ａｌ２Ｏ３層の傾斜角度数分布グラフにおいて、表５、６にそれぞれ示される通り、本発明被覆工具および比較被覆工具の改質α型Ａｌ２Ｏ３層は、（０００１）面の測定傾斜角の分布が、０〜４５度の範囲内の傾斜角区分に最高ピークが現れる傾斜角度数分布グラフを示した。また、表５、６には、改質α型Ａｌ２Ｏ３層の傾斜角度数分布グラフにおいて、０〜４５度の範囲内の傾斜角区分に存在する全傾斜角度数の傾斜角度数分布グラフ全体に占める割合を示した。
なお、図２は、本発明被覆工具１１の改質α型Ａｌ２Ｏ３層の０〜４５度の傾斜角区分を示す傾斜角度数分布グラフである。
In the gradient angle distribution graph of the modified α-type Al 2 O 3 layer obtained as a result, as shown in Tables 5 and 6, respectively, the modified α-type Al 2 O 3 layer of the present coated tool and the comparative coated tool Shows a gradient angle distribution graph in which the distribution of the measured inclination angle on the (0001) plane shows the highest peak in the inclination angle section within the range of 0 to 45 degrees. Tables 5 and 6 show the inclination angle number distribution graphs of all inclination angle numbers existing in the inclination angle sections in the range of 0 to 45 degrees in the inclination angle number distribution graph of the modified α-type Al 2 O 3 layer. The percentage of the total was shown.
FIG. 2 is an inclination angle number distribution graph showing inclination angle segments of 0 to 45 degrees of the modified α-type Al 2 O 3 layer of the coated tool 11 of the present invention.
また、本発明被覆工具１〜１３および比較被覆工具１〜１３の硬質被覆層の構成層の厚さを、走査型電子顕微鏡を用いて測定（縦断面測定）したところ、いずれも目標層厚と実質的に同じ平均層厚（５点測定の平均値）を示した。 Further, when the thicknesses of the constituent layers of the hard coating layers of the present coated tools 1 to 13 and the comparative coated tools 1 to 13 were measured using a scanning electron microscope (longitudinal cross section measurement), both of the target layer thickness and The substantially same average layer thickness (average value of 5-point measurement) was shown.
つぎに、上記の本発明被覆工具１〜１３および比較被覆工具１〜１３について、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、
被削材：ＪＩＳ・ＳＣＭ４３２の長さ方向等間隔４本縦溝入の丸棒、
切削速度： ４００ ｍ／ｍｉｎ．、
切り込み： ２．０ ｍｍ、
送り： ０．４５ ｍｍ／ｒｅｖ．、
切削時間： ５ 分、
の条件（切削条件Ａという）での合金鋼の乾式断続高速重切削試験（通常の切削速度および送りは、それぞれ、２００ｍ／ｍｉｎ．、０．３ｍｍ／ｒｅｖ．）、
被削材：ＪＩＳ・Ｓ３５Ｃの長さ方向等間隔２本縦溝入の丸棒、
切削速度： ３８０ ｍ／ｍｉｎ．、
切り込み： ３．０ ｍｍ、
送り： ０．３ ｍｍ／ｒｅｖ．、
切削時間： ５ 分、
の条件（切削条件Ｂという）での炭素鋼の乾式断続高速重切削試験（通常の切削速度および切り込みは、それぞれ、２００ｍ／ｍｉｎ．、１．５ｍｍ）、
被削材：ＪＩＳ・ＦＣＤ４５０の長さ方向等間隔４本縦溝入の丸棒、
切削速度： ３５０ ｍ／ｍｉｎ．、
切り込み： ２．０ ｍｍ、
送り： ０．５ ｍｍ／ｒｅｖ．、
切削時間： ５ 分、
の条件（切削条件Ｃという）でのダクタイル鋳鉄の乾式断続高速重切削試験（通常の切削速度および送りは、それぞれ、１８０ｍ／ｍｉｎ．、０．３ｍｍ／ｒｅｖ．）、
を行い、いずれの切削試験でも切刃の逃げ面摩耗幅を測定した。
この測定結果を表７に示した。
Next, for the above-described inventive coated tools 1 to 13 and comparative coated tools 1 to 13, both are screwed to the tip of the tool steel tool with a fixing jig,
Work material: JIS / SCM432 round bars with four equal intervals in the longitudinal direction,
Cutting speed: 400 m / min. ,
Cutting depth: 2.0 mm,
Feed: 0.45 mm / rev. ,
Cutting time: 5 minutes,
Dry intermittent high speed heavy cutting test of alloy steel under the following conditions (referred to as cutting condition A) (normal cutting speed and feed are 200 m / min. And 0.3 mm / rev., Respectively),
Work material: JIS / S35C lengthwise equal two round bars with vertical grooves,
Cutting speed: 380 m / min. ,
Cutting depth: 3.0 mm,
Feed: 0.3 mm / rev. ,
Cutting time: 5 minutes,
Dry intermittent high speed heavy cutting test of carbon steel under the following conditions (referred to as cutting condition B) (normal cutting speed and infeed are 200 m / min. And 1.5 mm, respectively),
Work material: JIS / FCD450 lengthwise equally spaced 4 bars with vertical grooves,
Cutting speed: 350 m / min. ,
Cutting depth: 2.0 mm,
Feed: 0.5 mm / rev. ,
Cutting time: 5 minutes,
Dry interrupted high speed heavy cutting test of ductile cast iron under the following conditions (referred to as cutting condition C) (normal cutting speed and feed are 180 m / min. And 0.3 mm / rev., Respectively),
In each cutting test, the flank wear width of the cutting edge was measured.
The measurement results are shown in Table 7.
表５〜７に示される結果から、本発明被覆工具１〜１３は、切刃稜線部の硬質被覆層の上部層がκ型Ａｌ２Ｏ３層で構成され、それ以外の領域（すくい面、逃げ面）の上部層がα型Ａｌ２Ｏ３層あるいは改質α型Ａｌ２Ｏ３層で構成されていることから、鋼や鋳鉄の切削加工を、高熱発生を伴い切刃に高負荷が作用する高速重切削条件で行っても、すぐれた耐チッピング性および耐摩耗性を示す。
これに対して、切刃稜線部を含め全ての領域において上部層がα型Ａｌ２Ｏ３層あるいは改質α型Ａｌ２Ｏ３層で構成されている比較被覆工具１、２、５、６、８〜１３においては、切刃稜線部で発生したチッピング、欠損が原因で寿命が短く、また、切刃稜線部を含め全ての領域において上部層がκ型Ａｌ２Ｏ３層で構成されている比較被覆工具３、４、７においては、耐摩耗性に劣り、いずれの比較被覆工具も短時間で使用寿命に至ることが明らかである。
From the results shown in Tables 5 to 7, in the present invention coated tools 1 to 13, the upper layer of the hard coating layer of the cutting edge ridge portion is composed of the κ-type Al 2 O 3 layer, and other regions (rake face, Since the upper layer of the flank) is composed of α-type Al 2 O 3 layer or modified α-type Al 2 O 3 layer, cutting of steel and cast iron is accompanied by high heat generation and high load is applied to the cutting edge. Excellent chipping and wear resistance even under high-speed heavy cutting conditions.
In contrast, comparative coating tools 1, 2, 5, 6 in which the upper layer is composed of an α-type Al 2 O 3 layer or a modified α-type Al 2 O 3 layer in all regions including the cutting edge ridge line portion. 8-13, the lifetime is short due to chipping and chipping generated at the cutting edge ridge, and the upper layer is composed of a κ-type Al 2 O 3 layer in all regions including the cutting edge ridge. The comparative coated tools 3, 4, and 7 are inferior in wear resistance, and it is apparent that any of the comparative coated tools reaches the service life in a short time.
上述のように、この発明の被覆工具は、各種鋼や鋳鉄などの通常の条件での連続切削や断続切削は勿論のこと、特に高熱発生を伴い切刃に高負荷が作用する高速重切削でも、すぐれた耐チッピング性および耐摩耗性を示し、長期に亘ってすぐれた切削性能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 described above, the coated tool of the present invention can be used not only for continuous cutting and intermittent cutting under normal conditions such as various types of steel and cast iron, but also for high-speed heavy cutting in which a high load acts on the cutting edge with high heat generation. Because it exhibits excellent chipping resistance and wear resistance, and exhibits excellent cutting performance over a long period of time, it is possible to improve the performance of cutting equipment, save labor and energy in cutting, and reduce costs It can respond satisfactorily.
Claims (2)
上記表面被覆切削工具の切刃稜線部に蒸着形成された上部層はκ型結晶構造を主体とする酸化アルミニウム層からなり、一方、前記切刃稜線部以外のすくい面および逃げ面に蒸着形成された上部層は実質的にα型結晶構造を主体とする酸化アルミニウム層からなることを特徴とする表面被覆切削工具。 Ti carbide layer, nitride layer, carbonitride layer, carbonate layer, nitride oxide layer, and hard coating layer on the surface of the tool base composed of tungsten carbide-based cemented carbide or titanium carbonitride-based cermet It consists of one or two or more of carbonitride oxide layers, and consists of a lower layer made of a Ti compound layer having a total average layer thickness of 3 to 20 μm and an aluminum oxide layer having an average layer thickness of 1 to 15 μm. In a surface-coated cutting tool in which an upper layer is formed by vapor deposition,
The upper layer formed by vapor deposition on the cutting edge ridge portion of the surface-coated cutting tool is composed of an aluminum oxide layer mainly composed of a κ-type crystal structure, while being formed by vapor deposition on the rake face and flank other than the cutting edge ridge line portion. A surface-coated cutting tool characterized in that the upper layer substantially comprises an aluminum oxide layer mainly composed of an α-type crystal structure.
上記α型結晶構造を主体とする酸化アルミニウム層について、電界放出型走査電子顕微鏡を用い、表面研磨面の測定範囲内に存在する六方晶結晶格子を有する結晶粒個々に電子線を照射して、前記表面研磨面の法線に対して、前記結晶粒の結晶面である（０００１）面の法線がなす傾斜角を測定し、前記測定傾斜角のうち、０〜４５度の範囲内にある測定傾斜角を０．２５度のピッチ毎に区分すると共に、各区分内に存在する度数を集計してなる傾斜角度数分布グラフを作成した場合、上記α型結晶構造を主体とする酸化アルミニウム層は、上記傾斜角度数分布グラフにおいて０〜１５度の範囲内の傾斜角区分に最高ピークが存在する酸化アルミニウム層である請求項１記載の表面被覆切削工具。 The surface-coated cutting tool according to claim 1,
For the aluminum oxide layer mainly composed of the α-type crystal structure, a field emission scanning electron microscope is used to irradiate the individual crystal grains having a hexagonal crystal lattice existing in the measurement range of the surface polished surface with an electron beam, The inclination angle formed by the normal line of the (0001) plane, which is the crystal plane of the crystal grain, is measured with respect to the normal line of the surface-polished surface, and is within the range of 0 to 45 degrees out of the measured inclination angle. When the measurement inclination angle is divided into pitches of 0.25 degrees, and an inclination angle number distribution graph is formed by summing up the frequencies existing in each division, the aluminum oxide layer mainly composed of the α-type crystal structure. The surface-coated cutting tool according to claim 1, which is an aluminum oxide layer having a highest peak in an inclination angle section within a range of 0 to 15 degrees in the inclination angle number distribution graph.
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