JP2013139064A - Surface-coated cutting tool with hard coating layer exhibiting superior chipping resistance in high-speed intermittent cutting work - Google Patents
Surface-coated cutting tool with hard coating layer exhibiting superior chipping resistance in high-speed intermittent cutting work Download PDFInfo
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この発明は、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 surface-coated cutting tool (hereinafter referred to as a coated tool) that exhibits high chipping resistance with a high-hardness coating layer in high-speed intermittent cutting with high heat generation and an impact load acting on the cutting edge. ).
従来、一般に、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、これらを総称して工具基体という）の表面に、
（ａ）下部層が、いずれも化学蒸着形成された、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、
（ｂ）上部層が、化学蒸着形成された、１〜２５μｍの平均層厚を有する酸化アルミニウム（以下、Ａｌ２Ｏ３で示す）層、
以上（ａ）および（ｂ）で構成された硬質被覆層を形成してなる被覆工具が良く知られている。
そして、上記の従来被覆工具は、比較的耐摩耗性に優れるものの、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、硬質被覆層の構造についての種々の提案がなされている。
Conventionally, generally on the surface of a substrate (hereinafter collectively referred to as a tool substrate) composed of a tungsten carbide (hereinafter referred to as WC) -based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) -based cermet. ,
(A) Ti carbide (hereinafter referred to as TiC) layer, nitride (hereinafter also referred to as TiN) layer, carbonitride (hereinafter referred to as TiCN) layer formed by chemical vapor deposition of the lower layers. A Ti compound layer consisting of two or more of a carbon oxide (hereinafter referred to as TiCO) layer and a carbonitride oxide (hereinafter referred to as TiCNO) layer and having a total average layer thickness of 3 to 20 μm,
(B) an aluminum oxide (hereinafter referred to as Al 2 O 3 ) layer having an average layer thickness of 1 to 25 μm, wherein the upper layer is formed by chemical vapor deposition;
A coated tool formed by forming a hard coating layer composed of (a) and (b) above is well known.
And although the above-mentioned conventional coated tools are relatively excellent in wear resistance, they tend to cause abnormal wear such as chipping when used under high-speed interrupted cutting conditions, so various proposals for the structure of the hard coating layer have been made. Has been made.
例えば、特許文献１に示すように、工具基体の表面に、３〜２０μｍの合計平均層厚を有するＴｉ化合物層（下部層）と、１〜１５μｍの平均層厚を有するＡｌ２Ｏ３層(上部層)を被覆し、かつ、Ｔｉ化合物層のうちの１層を、２．５〜１５μｍの平均層厚を有し、結晶粒の結晶面である｛１１２｝面の法線がなす傾斜角を測定した傾斜角度数分布グラフにおいて、０〜１０度の範囲内の傾斜角区分に最高ピークが存在すると共に、０〜１０度の範囲内に存在する度数の合計が、傾斜角度数分布グラフにおける度数全体の４５％以上の割合を占める傾斜角度数分布グラフを示すＴｉＣＮ層で構成することにより、 高速断続切削加工における耐チッピング性を改善することが提案されている。 For example, as shown in Patent Document 1, a Ti compound layer (lower layer) having a total average layer thickness of 3 to 20 μm and an Al 2 O 3 layer having an average layer thickness of 1 to 15 μm on the surface of the tool base ( The inclination angle formed by the normal of the {112} plane, which is the crystal plane of the crystal grain, has an average layer thickness of 2.5 to 15 μm and covers one of the Ti compound layers. In the inclination angle distribution graph, the highest peak exists in the inclination angle section in the range of 0 to 10 degrees, and the total of the frequencies existing in the range of 0 to 10 degrees is in the inclination angle distribution graph. It has been proposed to improve the chipping resistance in high-speed intermittent cutting by forming a TiCN layer showing an inclination angle distribution graph that accounts for 45% or more of the entire frequency.
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、高効率化の傾向にある。また、工具寿命の延命化を図るという観点から、硬質被覆層の厚膜化も求められているが、例えば、硬質被覆層（例えば、下部層のＴｉＣＮ層）の厚膜化を図った場合、上記従来の被覆工具においては、特にこれを厳しい切削条件の高速断続切削、すなわち、高熱発生を伴うとともに、切刃部にきわめて短いピッチで繰り返し断続的、衝撃的負荷が作用する高速断続切削で用いると、下部層のＴｉＣＮ層は、耐クラック伝播性が十分ではないため、切刃部にチッピングが発生しやすく、これが原因で、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 remarkably improved. On the other hand, there is a strong demand for labor-saving and energy-saving and further cost reduction for cutting work, and accordingly, cutting work tends to be further increased in speed and efficiency. Further, from the viewpoint of prolonging the tool life, it is also required to increase the thickness of the hard coating layer. For example, when increasing the thickness of the hard coating layer (for example, the TiCN layer of the lower layer), In the above-mentioned conventional coated tool, this is used particularly in high-speed intermittent cutting under severe cutting conditions, that is, high-speed intermittent cutting that involves high heat generation and that repeatedly and intermittently impacts at a very short pitch on the cutting edge. In addition, since the lower TiCN layer has insufficient crack propagation resistance, chipping is likely to occur at the cutting edge, and this causes the service life to be reached in a relatively short time.
そこで、本発明者等は、上述のような観点から、被覆工具の硬質被覆層の耐チッピング性向上をはかるべく、下部層を構成するＴｉＣＮ結晶粒の結晶方位傾斜角度分布割合と粒内平均方位差について着目し、鋭意研究を重ねた結果、次のような知見を得た。 Therefore, the present inventors, from the above viewpoint, in order to improve the chipping resistance of the hard coating layer of the coated tool, the crystal orientation inclination angle distribution ratio of the TiCN crystal grains constituting the lower layer and the intragranular average orientation The following findings were obtained as a result of intensive research focusing on the differences.
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、下部層として、３〜２０μｍの合計平均層厚を有するＴｉの炭化物（ＴｉＣ）層、窒化物（ＴｉＮ）層、炭窒化物（ＴｉＣＮ）層、炭酸化物ＴｉＣＯ）層および炭窒酸化（ＴｉＣＮＯ）物層のうちの１層または２層以上からなり、かつ、その内の少なくとも１層は２〜２０μｍの平均層厚を有する改質Ｔｉ炭窒化物（ＴｉＣＮ）層からなるＴｉ化合物層を形成し、また、上部層として、１〜１５μｍの平均層厚を有する酸化アルミニウム（Ａｌ２Ｏ３）層を蒸着形成するにあたり、Ｔｉ化合物層からなる下部層として特異な（１１２）面傾斜角度分布割合と粒内平均方位差を有する改質ＴｉＣＮ層を形成した後、この上に、例えば、通常の化学蒸着装置にて、目標上部層厚になるまでＡｌ２Ｏ３層を蒸着形成すると、蒸着形成された下部層の改質ＴｉＣＮ層は、すぐれた高温強度と密着性を備え、さらに、層内の歪が局所化されて存在するために、層内に発生したクラックの伝播・進展が抑制され、その結果として、耐チッピング性が向上することを見出したのである。 Ti carbide (TiC) layer and nitride (TiN) layer having a total average layer thickness of 3 to 20 μm as the lower layer on the surface of the tool base composed of tungsten carbide base cemented carbide or titanium carbonitride base cermet , A carbonitride (TiCN) layer, a carbon dioxide TiCO) layer, and a carbonitridation (TiCNO) layer, and at least one of them is an average layer of 2 to 20 μm A Ti compound layer composed of a modified Ti carbonitride (TiCN) layer having a thickness is formed, and an aluminum oxide (Al 2 O 3 ) layer having an average layer thickness of 1 to 15 μm is deposited as an upper layer. In this case, after forming a modified TiCN layer having a specific (112) plane inclination angle distribution ratio and an intragranular average orientation difference as a lower layer made of a Ti compound layer, for example, a normal chemical vapor deposition is formed thereon. When the Al 2 O 3 layer is vapor-deposited until the target upper layer thickness is reached by the deposition apparatus, the modified TiCN layer of the lower layer, which has been vapor-deposited, has excellent high-temperature strength and adhesiveness. It has been found that since the strain is localized, the propagation and propagation of cracks generated in the layer is suppressed, and as a result, the chipping resistance is improved.
したがって、このような硬質被覆層を備えた被覆切削工具を、例えば、鋼や鋳鉄などの、高熱発生を伴い、切刃に断続的、衝撃的負荷が作用する高速断続切削加工に用いた場合であっても、硬質被覆層を厚膜化しても、切刃部でのチッピングの発生が抑制され、長期の使用にわたって優れた耐摩耗性を発揮することができる。 Therefore, when a coated cutting tool equipped with such a hard coating layer is used for high-speed intermittent cutting, such as steel or cast iron, with high heat generation and intermittent and impact loads on the cutting edge. Even if the hard coating layer is thickened, the occurrence of chipping at the cutting edge portion is suppressed, and excellent wear resistance can be exhibited over a long period of use.
この発明は、上記の研究結果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、
（ａ）下部層が、３〜２０μｍの合計平均層厚を有する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、かつ、その内の少なくとも１層は２〜２０μｍの平均層厚を有する改質Ｔｉ炭窒化物層からなるＴｉ化合物層、
（ｂ）上部層が、１〜１５μｍの平均層厚を有する酸化アルミニウム層、
以上（ａ）および（ｂ）で構成された硬質被覆層を形成してなる表面被覆切削工具において、
（ｃ）上記（ａ）の改質Ｔｉ炭窒化物層について、電界放出型走査電子顕微鏡と電子後方散乱回折像装置を用い、断面研磨面の測定範囲内に存在する立方晶結晶格子を有する結晶粒個々に電子線を照射して、基体表面の法線に対して、前記結晶粒の結晶面である（１１２）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、０〜１０度の範囲内に存在する度数の合計が、傾斜角度数分布グラフにおける度数全体の２０〜８０％の割合を占める傾斜角度数分布グラフを示し、
（ｄ）上記（ａ）の改質Ｔｉ炭窒化物層について、電界放出型走査電子顕微鏡と電子後方散乱回折像装置を用い、断面研磨面の測定範囲内に存在する立方晶結晶格子を有する結晶粒個々に電子線を照射して、個々の結晶格子間の方位差（回転角）を測定し、隣接する測定点の結晶格子間の方位差（回転角）が５度以上である場合に、相互に隣接する測定点の境界は結晶粒界であるとし、結晶粒界に囲まれ、他の結晶粒界に分断されていない範囲を同一の結晶粒として特定し、さらに、結晶粒個々の結晶粒内平均方位差を求めた場合、結晶粒の結晶粒内平均方位差の平均が５度未満を示す結晶粒の面積割合が２０〜８０％を占め、一方、結晶粒の結晶粒内平均方位差の平均が５度以上を示す結晶粒の面積割合が２０〜８０％を占めることを特徴とする表面被覆切削工具。
（２）前記（１）（ｃ）に記載の結晶粒の結晶面である（１１２）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、０〜１０度の範囲内の傾斜角区分に存在する結晶粒の結晶粒内平均方位差の平均は５度未満を示し、一方、上記０〜１０度の範囲を外れる傾斜角区分に存在する結晶粒の結晶粒内平均方位差の平均は５度以上を示すことを特徴とする請求項１に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 was made based on the above research results,
“(1) On the surface of a tool base made of tungsten carbide-based cemented carbide or titanium carbonitride-based cermet,
(A) The lower layer is composed of one or more of Ti carbide layer, nitride layer, carbonitride layer, carbonate layer and carbonitride oxide layer having a total average layer thickness of 3 to 20 μm. And at least one of them is a Ti compound layer comprising a modified Ti carbonitride layer having an average layer thickness of 2 to 20 μm,
(B) an aluminum oxide layer whose upper layer has an average layer thickness of 1 to 15 μm,
In the surface-coated cutting tool formed with the hard coating layer composed of (a) and (b) above,
(C) For the modified Ti carbonitride layer of (a) above, a crystal having a cubic crystal lattice existing within the measurement range of the cross-sectional polished surface using a field emission scanning electron microscope and an electron backscatter diffraction image apparatus Each grain is irradiated with an electron beam, and the inclination angle formed by the normal of the (112) plane which is the crystal plane of the crystal grain is measured with respect to the normal of the substrate surface. When the measured inclination angle within the range of ˜45 degrees is divided into pitches of 0.25 degrees and the inclination angle number distribution graph is formed by counting the frequencies existing in each division, it is 0 to 10 degrees. An inclination angle frequency distribution graph in which the total of the frequencies existing in the range of 20% to 80% of the entire frequency in the inclination angle frequency distribution graph is shown,
(D) For the modified Ti carbonitride layer of (a) above, a crystal having a cubic crystal lattice existing within the measurement range of the cross-sectional polished surface using a field emission scanning electron microscope and an electron backscatter diffraction image apparatus When each grain is irradiated with an electron beam, the orientation difference (rotation angle) between individual crystal lattices is measured, and when the orientation difference (rotation angle) between crystal lattices at adjacent measurement points is 5 degrees or more, The boundary between the measurement points adjacent to each other is assumed to be a crystal grain boundary, and the range surrounded by the crystal grain boundary and not divided by other crystal grain boundaries is specified as the same crystal grain. When the average grain orientation difference is determined, the area ratio of the crystal grains in which the average grain average orientation difference is less than 5 degrees occupies 20 to 80%, while the grain average orientation within the grains The area ratio of crystal grains having an average difference of 5 degrees or more occupies 20 to 80%. Surface-coated cutting tool for.
(2) The inclination angle formed by the normal line of the (112) plane which is the crystal plane of the crystal grain described in (1) (c) is measured, and the measurement inclination angle is within a range of 0 to 45 degrees. A certain measured inclination angle is divided for each pitch of 0.25 degrees, and an inclination angle number distribution graph is created by summing up the frequencies existing in each section, and is divided into inclination angle sections within a range of 0 to 10 degrees. The average in-grain average orientation difference of the existing crystal grains is less than 5 degrees, while the average in-grain average orientation difference of the crystal grains existing in the tilt angle section outside the range of 0 to 10 degrees is 5 The surface-coated cutting tool according to claim 1, wherein the surface-coated cutting tool exhibits at least a degree. "
It has the characteristics.
つぎに、この発明の被覆工具の硬質被覆層の構成層について、より具体的に説明する。 Next, the constituent layers of the hard coating layer of the coated tool of the present invention will be described more specifically.
Ｔｉ化合物層（下部層）：
Ｔｉ化合物層は、自体が高温強度を有し、これの存在によって硬質被覆層が高温強度を具備するようになるほか、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もつが、その合計平均層厚が３μｍ未満では、前記作用を十分に発揮させることができず、一方その合計平均層厚が２０μｍを越えると、特に高熱発生を伴う高速断続切削で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、その合計平均層厚を３〜２０μｍと定めた。
Ti compound layer (lower layer):
The Ti compound layer itself has high-temperature strength, and the presence of the Ti compound layer makes the hard coating layer have high-temperature strength, and firmly adheres to both the tool base and the upper Al 2 O 3 layer. Therefore, it has an effect of improving the adhesion of the hard coating layer to the tool base, but if the total average layer thickness is less than 3 μm, the above-mentioned effect cannot be sufficiently exhibited, while the total average layer thickness is If it exceeds 20 μm, it becomes easy to cause thermoplastic deformation particularly in high-speed intermittent cutting with high heat generation, and this causes uneven wear. Therefore, the total average layer thickness is set to 3 to 20 μm.
この発明では、Ｔｉ化合物層からなる下部層の少なくとも１つの層として、改質ＴｉＣＮ層を設けることが必要である。
ここで、例えば、改質ＴｉＣＮ層は、まず、
反応ガス組成（容量％）：ＴｉＣｌ４２〜１０％、ＣＨ３ＣＮ０．５〜３％、ＣＨ４１〜５％、Ｎ２１０〜３０％、残りＨ２、
反応雰囲気温度：８２０〜９２０℃、
反応雰囲気圧力：６〜２０ｋＰａ、
という条件で該ＴｉＣＮ層を目標層厚の３０〜６０％の層厚となるまで成膜し、続けて、
反応ガス雰囲気：Ａｒ、
反応雰囲気温度：９００〜１０００℃、
反応雰囲気圧力：３〜１３ｋＰａ、
反応時間：５〜３０分、
という条件（加熱処理条件という）中で加熱処理を行うことによって改質ＴｉＣＮ層を形成することができる。
上記の工程にしたがって成膜することによって、特異な（１１２）面傾斜角度分布割合と粒内平均方位差を有する、耐クラック伝播性にすぐれた改質ＴｉＣＮ層を形成することができる。
なお、上記の工程で、特異な（１１２）面傾斜角度分布割合と粒内平均方位差が形成される機構は未だ解明されていないが、上記加熱処理によって、成長面に変化が生じ結晶粒内方位変化が起こるものと考えられる。
そして、この改質ＴｉＣＮ膜は、すぐれた高温強度と密着性に加え、層内に発生したクラックの伝播・進展を抑制する作用を有するので、改質ＴｉＣＮ層を少なくとも１層有するＴｉ化合物層からなる下部層は、高速断続切削加工においてすぐれた耐チッピング性を発揮する。
In the present invention, it is necessary to provide a modified TiCN layer as at least one of the lower layers made of the Ti compound layer.
Here, for example, the modified TiCN layer is
Reaction gas composition (volume%): TiCl 4 2 to 10%, CH 3 CN 0.5 to 3 %, CH 4 1 to 5%, N 2 10 to 30%, remaining H 2 ,
Reaction atmosphere temperature: 820-920 ° C.
Reaction atmosphere pressure: 6-20 kPa,
The TiCN layer is formed until the layer thickness reaches 30 to 60% of the target layer thickness under the conditions
Reaction gas atmosphere: Ar,
Reaction atmosphere temperature: 900-1000 ° C.
Reaction atmosphere pressure: 3 to 13 kPa,
Reaction time: 5-30 minutes,
The modified TiCN layer can be formed by performing heat treatment under the conditions (referred to as heat treatment conditions).
By forming the film according to the above steps, it is possible to form a modified TiCN layer having a unique (112) plane inclination angle distribution ratio and an intragranular average orientation difference and excellent in crack propagation resistance.
In addition, although the mechanism in which the unique (112) plane inclination angle distribution ratio and the intragranular average orientation difference are formed in the above process has not yet been elucidated, a change in the growth surface occurs due to the above heat treatment. It is thought that a change in direction occurs.
And this modified TiCN film has the effect of suppressing the propagation and progress of cracks generated in the layer in addition to excellent high-temperature strength and adhesion, and therefore, from the Ti compound layer having at least one modified TiCN layer. This lower layer exhibits excellent chipping resistance in high-speed intermittent cutting.
上記で成膜した下部層の改質ＴｉＣＮ層について、結晶傾斜角度分布割合等の解析を行うため、電界放出型走査電子顕微鏡と電子後方散乱回折像装置を用い、断面研磨面の測定範囲内に存在する立方晶結晶格子を有する結晶粒個々に電子線を照射して、基体表面の法線に対して、前記結晶粒の結晶面である（１１２）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ところ、０〜１０度の範囲内の傾斜角区分に最高ピークが存在すると共に、前記０〜１０度の範囲内に存在する度数の合計が、傾斜角度数分布グラフにおける度数全体の２０〜８０％の割合を占める傾斜角度数分布グラフを示した。
図１に、（１１２）面の法線がなす傾斜角を測定した傾斜角度数分布グラフの一例を示す。
上記の（１１２）面の傾斜角度分布割合について検討したところ、傾斜角度数分布グラフにおいて、０〜１０度の範囲内に存在する度数の合計が、度数全体の２０％未満、望ましくは４０％未満の割合の場合には、ＴｉＣＮ層の具備する耐摩耗性を十分に発揮することができず、一方、これが８０％、望ましくは７０％を超えると、改質ＴｉＣＮ層は、すぐれた高温強度を十分に発揮することができなくなることから、本発明では、（１１２）面の傾斜角度分布割合が、傾斜角度数分布グラフにおいて度数全体の２０〜８０％、好ましくは４０〜７０％の割合を占めるようにした。
また、上記で成膜した下部層の改質ＴｉＣＮ層の層厚について、層厚が２μｍ以下ではひずみの局所化が十分に起こらないため、改質ＴｉＣＮ層の具備するすぐれた耐チッピング性を十分に発揮することができず、一方これが２０μｍを超えると、特に高熱発生を伴う高速断続切削で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２〜２０μｍと定めた。
In order to analyze the crystal tilt angle distribution ratio etc. for the modified TiCN layer of the lower layer formed as described above, using a field emission scanning electron microscope and an electron backscatter diffraction image device, within the measurement range of the cross-section polished surface Each crystal grain having an existing cubic crystal lattice is irradiated with an electron beam, and the inclination angle formed by the normal of the (112) plane, which is the crystal plane of the crystal grain, is measured with respect to the normal of the substrate surface. An inclination angle number distribution graph obtained by dividing the measurement inclination angles within the range of 0 to 45 degrees out of the measurement inclination angles for each pitch of 0.25 degrees and totaling the frequencies existing in the respective sections. As a result, the highest peak is present in the inclination angle section in the range of 0 to 10 degrees, and the total of the frequencies existing in the range of 0 to 10 degrees is 20 of the entire degrees in the inclination angle frequency distribution graph. Inclination angle for a percentage of ~ 80% It shows a graph.
FIG. 1 shows an example of a tilt angle number distribution graph in which the tilt angle formed by the normal of the (112) plane is measured.
When the inclination angle distribution ratio of the (112) plane is examined, in the inclination angle frequency distribution graph, the total number of frequencies existing in the range of 0 to 10 degrees is less than 20%, preferably less than 40%. In the case of this ratio, the wear resistance of the TiCN layer cannot be sufficiently exhibited. On the other hand, when this exceeds 80%, desirably 70%, the modified TiCN layer has excellent high-temperature strength. In the present invention, the inclination angle distribution ratio of the (112) plane occupies a ratio of 20 to 80%, preferably 40 to 70% of the whole frequency in the inclination angle number distribution graph. I did it.
Further, regarding the layer thickness of the modified TiCN layer of the lower layer formed as described above, since the strain is not sufficiently localized when the layer thickness is 2 μm or less, the excellent chipping resistance provided by the modified TiCN layer is sufficient. On the other hand, if this exceeds 20 μm, it becomes easy to cause thermoplastic deformation particularly in high-speed intermittent cutting with high heat generation, and this causes uneven wear, so the average layer thickness is 2 to 20 μm. It was determined.
また、上記で成膜した下部層の改質ＴｉＣＮ層について、前記と同様に、電界放出型走査電子顕微鏡と電子後方散乱回折像装置を用い、表面研磨面の測定範囲内に存在する立方晶結晶格子を有する結晶粒個々に１００ｎｍ／ｓｔｅｐの間隔で、電子線を照射して、個々の結晶格子間の方位差（回転角）を測定し、隣接する測定点の結晶格子間の方位差（回転角）が５度以上である場合に、相互に隣接する測定点の境界は結晶粒界であるとし、結晶粒界に囲まれ、他の結晶粒界に分断されていない範囲を同一の結晶粒として特定し、さらに、それぞれの結晶粒における結晶粒内平均方位差を求めたところ、結晶粒の結晶粒内平均方位差の平均が５度未満を示す結晶粒の面積割合が２０〜８０％を占め、一方、結晶粒の結晶粒内平均方位差の平均が５度以上を示す結晶粒の面積割合が２０〜８０％を示した。上記の結晶粒内平均方位差の測定から、結晶粒の結晶粒内平均方位差の平均は５度未満を示す結晶、５度以上を示す結晶が共に２０〜８０％を占めていることから、本発明で成膜された下部層の改質ＴｉＣＮ層には、歪が局所化して存在することが分かる。
図２に、結晶粒内平均方位差の概念図を示す。即ち、図２（ａ）、（ｂ）のいずれにおいても、結晶粒内（結晶粒界内部）のマス目で示される各測定点における測定角度の大きさを、それぞれのマス目の矢印で表示しているが、「結晶粒内平均方位差が５度未満の結晶粒」を示す（ａ）においては、いずれの測定点においても同程度の測定角度を示し、一方、「結晶粒内平均方位差が５度以上の結晶粒」を示す（ｂ）においては、測定点によって次第に測定角度が変化しており、結晶粒の結晶粒内平均方位差が大きくなっている（５度以上）ことを示している。
つまり、結晶粒の結晶粒内平均方位差の平均が５度以上である結晶粒内部に、下部層の改質ＴｉＣＮ層のひずみが局所的に偏在分布し、その結果として、下部層の改質ＴｉＣＮ層に発生・伝播したクラックがひずみの多い箇所に優先的に進展し、その後ひずみの少ない箇所への伝播・進展を抑制することができるため、チッピング等の異常損傷の発生を防止することができる。
上記結晶粒内平均方位差の割合について検討したところ、結晶粒内平均方位差の平均が５度以上を示す結晶粒の面積割合が２０％未満の場合、または８０％以上の場合には、クラック伝播を抑止する歪みの局所化が十分に起こらず、すぐれた耐チッピング性を発揮することができなくなるため、結晶粒内平均方位差の平均が５度以上を示す結晶粒の面積割合が２０〜８０％を占めるようにした。
Further, for the modified TiCN layer of the lower layer formed as described above, similarly to the above, using a field emission scanning electron microscope and an electron backscatter diffraction image apparatus, cubic crystals existing within the measurement range of the surface polished surface Each crystal grain having a lattice is irradiated with an electron beam at an interval of 100 nm / step to measure an orientation difference (rotation angle) between individual crystal lattices, and an orientation difference (rotation) between crystal lattices at adjacent measurement points. When the angle is 5 degrees or more, the boundary between the measurement points adjacent to each other is assumed to be a crystal grain boundary, and the same crystal grain is surrounded by the crystal grain boundary and is not divided by other crystal grain boundaries. Further, when the average orientation difference within the crystal grains in each crystal grain was determined, the area ratio of the crystal grains having an average average orientation difference within the crystal grains of less than 5 degrees was 20 to 80%. On the other hand, the average of the average orientation difference within the crystal grains Area ratio of crystal grains showing a 5 degrees or more showed 20-80%. From the measurement of the above-mentioned average orientation difference within the crystal grain, the average of the average orientation difference within the crystal grain of the crystal grains is less than 5 degrees, both the crystals showing 5 degrees or more account for 20 to 80%, It can be seen that the strain is localized in the lower modified TiCN layer formed in the present invention.
In FIG. 2, the conceptual diagram of the average orientation difference in a crystal grain is shown. That is, in both FIGS. 2A and 2B, the magnitude of the measurement angle at each measurement point indicated by the square in the crystal grain (inside the grain boundary) is indicated by the arrow of each square. However, in (a) showing “crystal grains having an average misorientation within a crystal grain of less than 5 degrees”, the same measurement angle is shown at any measurement point. In (b), which shows “grains with a difference of 5 degrees or more”, the measurement angle gradually changes depending on the measurement point, and the average orientation difference within the crystal grains is larger (5 degrees or more). Show.
In other words, the strain of the modified TiCN layer in the lower layer is locally distributed in the crystal grains whose average orientation difference within the crystal grains is 5 degrees or more, and as a result, the modification of the lower layer is performed. Since cracks generated and propagated in the TiCN layer preferentially propagate to places with a lot of strain and then can be prevented from propagating and progress to places with little strain, the occurrence of abnormal damage such as chipping can be prevented. it can.
When the ratio of the average misorientation within the crystal grains was examined, the area ratio of the crystal grains showing the average misorientation within the crystal grains of 5 degrees or more is less than 20%, or 80% or more, the cracks Since the localization of the strain for suppressing the propagation does not sufficiently occur and the chipping resistance cannot be exhibited, the area ratio of the crystal grains in which the average of the average orientation difference within the crystal grains is 5 degrees or more is 20 to 80%.
また、基体表面の法線に対して、前記結晶粒の結晶面である（１１２）面の法線がなす傾斜角を測定し、０〜４５度の範囲内にある前記測定傾斜角を０．２５度のピッチ毎に区分した際、上記０〜１０度の範囲内の傾斜角区分に存在する結晶粒の結晶粒内平均方位差の平均は５度未満を示し、一方、上記０〜１０度の範囲を外れる傾斜角区分に存在する結晶粒の結晶粒内平均方位差の平均は５度以上を示すことが望ましい。
これは、上記０〜１０度の範囲内の傾斜角区分に存在する結晶粒の結晶粒内平均方位差の平均が５度未満であり、かつ、０〜１０度の範囲を外れる傾斜角区分に存在する結晶粒の結晶粒内平均方位差の平均が５度以上である場合には、下部層の改質ＴｉＣＮ層のひずみがより局所的に発生し、耐チッピング性、耐異常損傷性の向上を図ることができるためである。
In addition, an inclination angle formed by a normal line of the (112) plane which is a crystal plane of the crystal grain is measured with respect to a normal line of the substrate surface, and the measured inclination angle within a range of 0 to 45 degrees is set to 0. When divided into 25 degree pitches, the average in-grain average orientation difference of the crystal grains present in the inclination angle section within the range of 0 to 10 degrees is less than 5 degrees, while the above 0 to 10 degrees It is desirable that the average of in-grain average orientation difference of the crystal grains existing in the tilt angle section out of the range is 5 degrees or more.
This is because the average in-grain average orientation difference of the grains existing in the tilt angle section within the range of 0 to 10 degrees is less than 5 degrees, and the tilt angle section is outside the range of 0 to 10 degrees. If the average grain orientation difference of existing grains is 5 degrees or more, the deformation of the modified TiCN layer of the lower layer occurs more locally, improving chipping resistance and abnormal damage resistance It is because it can plan.
Ａｌ２Ｏ３層（上部層）：
Ａｌ２Ｏ３層は、一般的にすぐれた高温硬さと耐熱性を有し、硬質被覆層の耐摩耗性向上に寄与するが、その平均層厚が１μｍ未満では、硬質被覆層に十分な耐摩耗性を発揮せしめることができない。一方、平均層厚が１５μｍを越えて厚くなりすぎると、チッピング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。
なお、Ａｌ２Ｏ３層の成膜は、従来から良く知られているＣＶＤ法等によって行うことができ、その成膜法について特段制限されるものではない。
Al 2 O 3 layer (upper layer):
The Al 2 O 3 layer generally has excellent high-temperature hardness and heat resistance and contributes to improving the wear resistance of the hard coating layer. However, if the average layer thickness is less than 1 μm, sufficient resistance to the hard coating layer is achieved. Abrasion cannot be demonstrated. On the other hand, if the average layer thickness exceeds 15 μm and becomes too thick, chipping is likely to occur. Therefore, the average layer thickness was set to 1 to 15 μm.
The Al 2 O 3 layer can be formed by a conventionally well-known CVD method or the like, and the film forming method is not particularly limited.
硬質被覆層として、Ｔｉ化合物層からなる下部層とＡｌ２Ｏ３層からなる上部層を蒸着形成し、しかも、下部層として少なくとも１層の改質ＴｉＣＮ層を形成したこの発明の被覆工具は、下部層の改質ＴｉＣＮ層が、（１１２）面の法線がなす傾斜角を測定・集計してなる傾斜角度数分布グラフを作成した場合、０〜１０度の範囲内の傾斜角区分に最高ピークが存在すると共に、前記０〜１０度の範囲内に存在する度数の合計が、傾斜角度数分布グラフにおける度数全体の２０〜８０％の割合を占めるため、優れた高温強度、密着強度および耐クラック伝播性を備え、さらに、下部層の改質ＴｉＣＮ結晶粒それぞれについて、結晶粒内平均方位差を求めた場合、結晶粒の結晶粒内平均方位差の平均が５度未満を示す結晶粒の面積割合が２０〜８０％を占め、一方、結晶粒の結晶粒内平均方位差の平均が５度以上を示す結晶粒の面積割合が２０〜８０％を占めることから、下部層の改質ＴｉＣＮ層に内在する歪が局所化して存在するため、下部層の改質ＴｉＣＮ層内に発生・伝播したクラックのさらなる伝播・進展を抑制することができる。
したがって、この発明の被覆工具は、高熱発生を伴うとともに、切刃部に断続的、衝撃的負荷が作用する高速断続切削に用いた場合でも、チッピング等の異常損傷を発生することなく、長期の使用に亘ってすぐれた耐摩耗性を発揮するものである。
As the hard coating layer, a lower layer made of a Ti compound layer and an upper layer made of an Al 2 O 3 layer are formed by vapor deposition, and at least one modified TiCN layer is formed as a lower layer. When the modified TiCN layer of the lower layer measures and counts the inclination angle formed by the normal of the (112) plane, it is the highest in the inclination angle category within the range of 0 to 10 degrees. Since the peak is present and the total frequency within the range of 0 to 10 degrees occupies 20 to 80% of the total frequency in the gradient angle distribution graph, excellent high temperature strength, adhesion strength and resistance For each of the modified TiCN crystal grains of the lower layer having crack propagation properties, when the average in-grain orientation difference is obtained, the average of the in-grain average orientation difference of the crystal grains is less than 5 degrees The area ratio is 20 On the other hand, since the area ratio of crystal grains in which the average in-grain average orientation difference of crystal grains is 5 degrees or more occupies 20 to 80%, the strain inherent in the modified TiCN layer of the lower layer Therefore, it is possible to suppress further propagation / progress of cracks generated / propagated in the modified TiCN layer of the lower layer.
Therefore, the coated tool of the present invention is accompanied by high heat generation, and even when used for high-speed intermittent cutting in which intermittent and impact loads are applied to the cutting edge portion, it does not cause abnormal damage such as chipping. It exhibits excellent wear resistance over use.
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、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に規定するインサート形状をもったＷＣ基超硬合金製の工具基体Ａ〜Ｄをそれぞれ製造した。 As raw material powders, 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 are prepared. Then, blended into the composition shown in Table 1, added with wax, ball mill mixed in acetone for 24 hours, dried under reduced pressure, and then press-molded into a green compact of a predetermined shape at a pressure of 98 MPa. Is vacuum-sintered at a predetermined temperature in the range of 1370 to 1470 ° C. for 1 hour in a vacuum of 5 Pa. After sintering, the cutting edge is subjected to honing of R: 0.07 mm. -WC base cemented carbide tool bases A to D each having an insert shape specified in 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、Ｍｏ2Ｃ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のインサート形状をもったＴｉＣＮ基サーメット製の工具基体ａ〜ｄ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 d made of TiCN-based cermet having an insert shape of standard / CNMG12041 were formed.
つぎに、これらの工具基体Ａ〜Ｄおよび工具基体ａ〜ｄの表面に、通常の化学蒸着装置を用い、硬質被覆層の下部層として、表３に示される条件で、かつ、表５に示される組み合わせ及び目標層厚でＴｉ化合物層を蒸着形成した。
なお、下部層のうちの少なくとも１つの層として、改質ＴｉＣＮ層を蒸着したが、改質ＴｉＣＮ層の加熱処理条件は表４に示す。
ついで、上部層としてのＡｌ２Ｏ３層を、表３に示される条件にて、かつ、表５に示される目標層厚で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。
Next, on the surfaces of these tool bases A to D and tool bases a to d, using a normal chemical vapor deposition apparatus, the lower layer of the hard coating layer is subjected to the conditions shown in Table 3 and shown in Table 5. The Ti compound layer was formed by vapor deposition with the combination and target layer thickness.
The modified TiCN layer was deposited as at least one of the lower layers. Table 4 shows the heat treatment conditions for the modified TiCN layer.
Then, by depositing the Al 2 O 3 layer as the upper layer under the conditions shown in Table 3 and with the target layer thickness shown in Table 5,
The present coated tools 1 to 13 were produced, respectively.
また、比較の目的で、硬質被覆層の下部層として、表３に示される条件で、かつ、表５に示される組み合わせ及び目標層厚、一部については表４に示される加熱条件でＴｉ化合物層を蒸着形成し、
ついで、上部層としてのＡｌ２Ｏ３層を、表３に示される条件にて、かつ、表６に示される目標層厚で蒸着形成することにより、
比較例被覆工具１〜１３をそれぞれ製造した。
For the purpose of comparison, as a lower layer of the hard coating layer, the Ti compound under the conditions shown in Table 3 and the combinations and target layer thicknesses shown in Table 5 and partly the heating conditions shown in Table 4 Depositing layers,
Next, an Al 2 O 3 layer as an upper layer is formed by vapor deposition under the conditions shown in Table 3 and with the target layer thickness shown in Table 6.
Comparative example coated tools 1 to 13 were produced.
ついで、上記の本発明被覆工具の下部層の改質ＴｉＣＮ層と、比較例被覆工具の下部層のＴｉＣＮ層について、電界放出型走査電子顕微鏡と電子後方散乱回折像装置を用いて、傾斜角度数分布グラフをそれぞれ作成した。
まず、傾斜角度数分布グラフは、下部層の改質ＴｉＣＮ層の縦断面を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、前記断面研磨面の測定範囲内に存在する立方晶結晶格子を有する結晶粒個々に照射し、電子後方散乱回折像装置を用いて、基体表面方向に幅５０μｍの領域を０．１μｍ／ｓｔｅｐの間隔で、基体表面の法線に対して、前記結晶粒の結晶面である（１１２）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。
表５、表６に、上記で求めた傾斜角度数分布グラフにおいて、度数全体に占める０〜１０度の範囲内の傾斜角区分に存在する度数割合を示す。
図１に、一例として、本発明被覆工具１について作成した傾斜角度数分布グラフを示す。
Next, with respect to the modified TiCN layer of the lower layer of the above-described coated tool of the present invention and the TiCN layer of the lower layer of the comparative coated tool, the number of tilt angles was measured using a field emission scanning electron microscope and an electron backscatter diffraction image apparatus. Each distribution graph was created.
First, the inclination angle number distribution graph is set in a lens barrel of a field emission scanning electron microscope with the vertical section of the modified TiCN layer of the lower layer as a polished surface, and an incident angle of 70 degrees on the polished surface. An electron beam with an accelerating voltage of 15 kV is irradiated at an irradiation current of 1 nA on each crystal grain having a cubic crystal lattice existing within the measurement range of the cross-sectional polished surface, and an electron backscatter diffraction image apparatus is used to The inclination angle formed by the normal of the (112) plane, which is the crystal plane of the crystal grain, is measured with respect to the normal of the substrate surface at an interval of 0.1 μm / step in a region having a width of 50 μm in the surface direction. Based on the measurement result, among the measurement inclination angles, the measurement inclination angles in the range of 0 to 45 degrees are divided for each pitch of 0.25 degrees, and the frequencies existing in each division are totaled. Created.
Tables 5 and 6 show the frequency ratios existing in the tilt angle sections in the range of 0 to 10 degrees in the entire frequency in the tilt angle number distribution graph obtained above.
FIG. 1 shows, as an example, an inclination angle number distribution graph created for the coated tool 1 of the present invention.
また、上記の本発明被覆工具の下部層の改質ＴｉＣＮ層と、比較例被覆工具の硬質被覆層の下部層のＴｉＣＮ層について、電界放出型走査電子顕微鏡と電子後方散乱回折像装置を用いて、結晶粒を特定することにより、特定されたそれぞれの結晶粒における結晶粒内平均方位差を測定した。
具体的には、上記の改質ＴｉＣＮ層あるいはＴｉＣＮ層の縦断面を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、前記断面研磨面の測定範囲内に存在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、基体表面方向に幅５０μｍの領域を０．１μｍ／ｓｔｅｐの間隔で、個々の結晶格子間の方位差（回転角）を個々の結晶格子のオイラー角の差から測定し、隣接する測定点の結晶格子間の方位差（回転角）が５度以上である場合に、相互に隣接する測定点の境界は結晶粒界であるとし、結晶粒界に囲まれ、他の結晶粒界に分断されていない範囲を同一の結晶粒として特定し、それぞれの結晶粒内方位差を測定し、得られた結晶粒内方位差を平均し、これをその結晶粒における結晶粒内平均方位差とした。
表５、表６に、上記で求めた結晶粒内平均方位差を示す。
Moreover, the modified TiCN layer of the lower layer of the above-described coated tool of the present invention and the TiCN layer of the lower layer of the hard coated layer of the comparative example coated tool were used using a field emission scanning electron microscope and an electron backscatter diffraction image apparatus. By specifying the crystal grains, the average orientation difference within the crystal grains in each of the specified crystal grains was measured.
Specifically, the modified TiCN layer or the TiCN layer is set in a lens barrel of a field emission scanning electron microscope in a state where the longitudinal section of the TiCN layer is a polished surface, and 15 kV at an incident angle of 70 degrees on the polished surface. An electron beam with an accelerating voltage of 1 nm is irradiated to each crystal grain existing within the measurement range of the cross-sectional polished surface with an irradiation current of 1 nA, and an electron backscatter diffraction image apparatus is used to form a region having a width of 50 μm in the substrate surface direction At an interval of 0.1 μm / step, an orientation difference (rotation angle) between individual crystal lattices is measured from a difference in Euler angle between individual crystal lattices, and an orientation difference (rotation angle) between crystal lattices at adjacent measurement points. If the angle is 5 degrees or more, the boundary between adjacent measurement points is assumed to be a crystal grain boundary, and the range surrounded by the crystal grain boundary and not divided by other crystal grain boundaries is specified as the same crystal grain And each crystal grain orientation difference was measured and obtained. The crystal grain orientation difference was averaged, and this was defined as the crystal grain average orientation difference in the crystal grain.
Tables 5 and 6 show the average orientation difference within the crystal grains determined above.
上記の改質ＴｉＣＮ層の傾斜角度数分布グラフおよび結晶粒内平均方位差において、表５、表６にそれぞれ示される通り、本発明被覆工具の改質ＴｉＣＮ層は、（１１２）面傾斜角度分布割合が高く（傾斜角度数分布グラフにおける度数全体の２０〜８０％の割合）、結晶粒の結晶粒内平均方位差の平均が５度未満を示す結晶粒の面積割合が２０〜８０％を占め、一方、結晶粒の結晶粒内平均方位差の平均が５度以上を示す結晶粒の面積割合が２０〜８０％を占め、また、本発明被覆工具の一部については傾斜角度数分布グラフにおいて０〜１０度の範囲内の傾斜角区分に存在する結晶粒の結晶粒内平均方位差の平均は５度未満を示し、一方、上記０〜１０度の範囲を外れる傾斜角区分に存在する結晶粒の結晶粒内平均方位差の平均は５度以上を示した。
これに対して、比較例被覆工具においては、（１１２）面傾斜角度分布割合は本発明被覆工具と同等であるが（傾斜角度数分布グラフにおける度数全体の２０〜８０％の割合）、結晶粒の結晶粒内平均方位差の平均が５度未満を示す結晶粒の面積割合が８０％を超えて占め、または２０％未満を占め、一方、結晶粒の結晶粒内平均方位差の平均が５度以上を示す結晶粒の面積割合が２０％未満を占め、または８０％を超えて占めることを示した。
In the above-mentioned modified TiCN layer tilt angle distribution graph and in-grain average orientation difference, as shown in Table 5 and Table 6, respectively, the modified TiCN layer of the coated tool of the present invention has a (112) plane tilt angle distribution. The ratio of the crystal grain area ratio is high (ratio of 20 to 80% of the entire frequency in the tilt angle number distribution graph), and the average orientation difference within the crystal grains is less than 5 degrees. On the other hand, the area ratio of the crystal grains in which the average of the average orientation difference within the crystal grains of the crystal grains is 5 degrees or more occupies 20 to 80%. The average of in-grain average misorientation of crystal grains existing in the tilt angle section within the range of 0 to 10 degrees is less than 5 degrees, while the crystal existing in the tilt angle section outside the range of 0 to 10 degrees The average average grain orientation difference of grains is 5 degrees or more It is shown.
On the other hand, in the comparative example coated tool, the (112) plane inclination angle distribution ratio is equivalent to that of the present invention coated tool (a ratio of 20 to 80% of the entire frequency in the inclination angle number distribution graph), but the crystal grains The average proportion of crystal grains having an average misorientation of less than 5 degrees accounts for more than 80% or less than 20%, while the mean misorientation of crystal grains is less than 5%. It was shown that the area ratio of the crystal grains showing the degree or more occupied less than 20% or more than 80%.
さらに、上記の本発明被覆工具１〜１３および比較例被覆工具１〜１３の各層の層厚を、走査型電子顕微鏡を用いて測定（同じく縦断面測定）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 layer thicknesses of the respective layers of the present invention coated tools 1 to 13 and comparative example coated tools 1 to 13 were measured using the scanning electron microscope (same longitudinal section measurement), both were substantially equal to the target layer thickness. The same average layer thickness (average value of 5-point measurement) was shown.
つぎに、上記の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１〜１３および比較例被覆工具１〜１３について、
被削材：ＪＩＳ・Ｓ３０Ｃの長さ方向等間隔４本縦溝入り丸棒、
切削速度：３６０ｍ／ｍｉｎ、
切り込み：１．２ｍｍ、
送り：０．２５ｍｍ／ｒｅｖ、
切削時間：６分、
の条件（切削条件Ａ）での炭素鋼の湿式高速断続切削試験（通常の切削速度は、２００ｍ／ｍｉｎ）、
被削材：ＪＩＳ・ＳＣＭ４１５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：０．２５ｍｍ／ｒｅｖ、
切削時間：６分、
の条件（切削条件Ｂ）での合金鋼の湿式高速断続切削試験（通常の切削速度は、２００ｍ／ｍｉｎ）、
被削材：ＪＩＳ・ＦＣＤ４５０の長さ方向等間隔４本縦溝入り丸棒、
切削速度：３８０ｍ／ｍｉｎ、
切り込み：２．５ｍｍ、
送り：０．３ｍｍ／ｒｅｖ、
切削時間：６分、
の条件（切削条件Ｃ）でのダクタイル鋳鉄の湿式高速断続切削試験（通常の切削速度は、１８０ｍ／ｍｉｎ）、
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, in the state where each of the above various coated tools is screwed to the tip of the tool steel tool with a fixing jig, the present coated tools 1 to 13 and the comparative coated tools 1 to 13 are as follows.
Work material: JIS / S30C lengthwise equal length 4 round bar with round groove,
Cutting speed: 360 m / min,
Cutting depth: 1.2mm,
Feed: 0.25mm / rev,
Cutting time: 6 minutes
Wet high-speed intermittent cutting test of carbon steel under the conditions (cutting condition A) (normal cutting speed is 200 m / min),
Work material: JIS / SCM415 lengthwise equidistant 4 round grooved round bars,
Cutting speed: 370 m / min,
Cutting depth: 2.0 mm
Feed: 0.25mm / rev,
Cutting time: 6 minutes
Wet high-speed intermittent cutting test of alloy steel under the above conditions (cutting condition B) (normal cutting speed is 200 m / min),
Work material: JIS / FCD450 lengthwise equidistant round bars with 4 vertical grooves,
Cutting speed: 380 m / min,
Incision: 2.5mm,
Feed: 0.3mm / rev,
Cutting time: 6 minutes
Wet high-speed intermittent cutting test (normal cutting speed is 180 m / min) of ductile cast iron under the above conditions (cutting condition C),
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、下部層の改質ＴｉＣＮ層の（１１２）面の傾斜角度分布割合が傾斜角度数分布グラフにおける度数全体の２０〜８０％であり、また、結晶粒内平均方位差の平均が５度以上の結晶粒の面積割合が２０〜８０％であった。また、本発明被覆工具の一部においては傾斜角度数分布グラフにおいて０〜１０度の範囲内の傾斜角区分に存在する結晶粒の結晶粒内平均方位差の平均は５度未満、一方、上記０〜１０度の範囲を外れる傾斜角区分に存在する結晶粒の結晶粒内平均方位差の平均は５度以上を示した。これらのことから下部層の改質ＴｉＣＮ層が、高温強度および密着性に優れると同時に、耐クラック伝播性にすぐれ層内のクラックの伝播・進展を抑制することから、高熱発生を伴い、切刃部に断続的、衝撃的負荷が作用する高速断続切削に用いた場合でも、すぐれた耐チッピング性を示し、長期の使用に亘ってすぐれた耐摩耗性を発揮するものであった。
これに対して、比較例被覆工具１〜１３については、いずれも、高速断続切削加工では硬質被覆層にチッピングが発生し、比較的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 coated tools 1 to 13 of the present invention, the inclination angle distribution ratio of the (112) plane of the modified TiCN layer of the lower layer is 20 to 80% of the entire frequency in the inclination angle number distribution graph. Moreover, the area ratio of the crystal grains whose average orientation difference within the crystal grains is 5 degrees or more was 20 to 80%. Further, in some of the coated tools of the present invention, the average of the in-grain average orientation difference of the grains existing in the tilt angle section in the range of 0 to 10 degrees in the tilt angle number distribution graph is less than 5 degrees, while the above The average of the in-grain average orientation difference of the crystal grains existing in the tilt angle section outside the range of 0 to 10 degrees was 5 degrees or more. From these, the modified TiCN layer of the lower layer is excellent in high-temperature strength and adhesion, and at the same time has excellent crack propagation resistance and suppresses the propagation and propagation of cracks in the layer. Even when used for high-speed intermittent cutting in which intermittent and impact loads are applied to the part, it exhibits excellent chipping resistance and exhibits excellent wear resistance over a long period of use.
On the other hand, as for all of the comparative example coated tools 1 to 13, it is apparent that chipping occurs in the hard coating layer in the high-speed intermittent cutting, and the service life is reached in a relatively 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、切刃部に断続的、衝撃的負荷が作用する高速断続切削に用いた場合でも、すぐれた耐チッピング性を示し、長期の使用に亘ってすぐれた耐摩耗性を発揮するものであるから、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 is not only continuous and intermittent cutting under normal conditions such as various steels and cast irons, but particularly with high heat generation, the cutting edge portion has intermittent and impact loads. Even when used for high-speed intermittent cutting that acts, it exhibits excellent chipping resistance and excellent wear resistance over a long period of use. And it can cope with energy saving and cost reduction sufficiently satisfactorily.
Claims (2)
（ａ）下部層が、３〜２０μｍの合計平均層厚を有する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、かつ、その内の少なくとも１層は２〜２０μｍの平均層厚を有する改質Ｔｉ炭窒化物層からなるＴｉ化合物層、
（ｂ）上部層が、１〜１５μｍの平均層厚を有する酸化アルミニウム層、
以上（ａ）および（ｂ）で構成された硬質被覆層を形成してなる表面被覆切削工具において、
（ｃ）上記（ａ）の改質Ｔｉ炭窒化物層について、電界放出型走査電子顕微鏡と電子後方散乱回折像装置を用い、断面研磨面の測定範囲内に存在する立方晶結晶格子を有する結晶粒個々に電子線を照射して、基体表面の法線に対して、前記結晶粒の結晶面である（１１２）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、０〜１０度の範囲内に存在する度数の合計が、傾斜角度数分布グラフにおける度数全体の２０〜８０％の割合を占める傾斜角度数分布グラフを示し、
（ｄ）上記（ａ）の改質Ｔｉ炭窒化物層について、電界放出型走査電子顕微鏡と電子後方散乱回折像装置を用い、断面研磨面の測定範囲内に存在する立方晶結晶格子を有する結晶粒個々に電子線を照射して、個々の結晶格子間の方位差（回転角）を測定し、隣接する測定点の結晶格子間の方位差（回転角）が５度以上である場合に、相互に隣接する測定点の境界は結晶粒界であるとし、結晶粒界に囲まれ、他の結晶粒界に分断されていない範囲を同一の結晶粒として特定し、さらに、結晶粒個々の結晶粒内平均方位差を求めた場合、結晶粒の結晶粒内平均方位差の平均が５度未満を示す結晶粒の面積割合が２０〜８０％を占め、一方、結晶粒の結晶粒内平均方位差の平均が５度以上を示す結晶粒の面積割合が２０〜８０％を占めることを特徴とする表面被覆切削工具。 On the surface of the tool base composed of tungsten carbide based cemented carbide or titanium carbonitride based cermet,
(A) The lower layer is composed of one or more of Ti carbide layer, nitride layer, carbonitride layer, carbonate layer and carbonitride oxide layer having a total average layer thickness of 3 to 20 μm. And at least one of them is a Ti compound layer comprising a modified Ti carbonitride layer having an average layer thickness of 2 to 20 μm,
(B) an aluminum oxide layer whose upper layer has an average layer thickness of 1 to 15 μm,
In the surface-coated cutting tool formed with the hard coating layer composed of (a) and (b) above,
(C) For the modified Ti carbonitride layer of (a) above, a crystal having a cubic crystal lattice existing within the measurement range of the cross-sectional polished surface using a field emission scanning electron microscope and an electron backscatter diffraction image apparatus Each grain is irradiated with an electron beam, and the inclination angle formed by the normal of the (112) plane which is the crystal plane of the crystal grain is measured with respect to the normal of the substrate surface. When the measured inclination angle within the range of ˜45 degrees is divided into pitches of 0.25 degrees and the inclination angle number distribution graph is formed by counting the frequencies existing in each division, it is 0 to 10 degrees. An inclination angle frequency distribution graph in which the total of the frequencies existing in the range of 20% to 80% of the entire frequency in the inclination angle frequency distribution graph is shown,
(D) For the modified Ti carbonitride layer of (a) above, a crystal having a cubic crystal lattice existing within the measurement range of the cross-sectional polished surface using a field emission scanning electron microscope and an electron backscatter diffraction image apparatus When each grain is irradiated with an electron beam, the orientation difference (rotation angle) between individual crystal lattices is measured, and when the orientation difference (rotation angle) between crystal lattices at adjacent measurement points is 5 degrees or more, The boundary between the measurement points adjacent to each other is assumed to be a crystal grain boundary, and the range surrounded by the crystal grain boundary and not divided by other crystal grain boundaries is specified as the same crystal grain. When the average grain orientation difference is determined, the area ratio of the crystal grains in which the average grain average orientation difference is less than 5 degrees occupies 20 to 80%, while the grain average orientation within the grains The area ratio of crystal grains having an average difference of 5 degrees or more occupies 20 to 80%. Surface-coated cutting tool for.
A tilt angle formed by a normal of the (112) plane which is a crystal plane of the crystal grain according to claim 1 (c) is measured, and a measured tilt angle within a range of 0 to 45 degrees among the measured tilt angles. Are divided into pitches of 0.25 degrees, and a frequency distribution graph is created by summing up the frequencies existing in each section, and crystal grains existing in the tilt angle sections in the range of 0 to 10 degrees. The average in-grain average orientation difference is less than 5 degrees, while the average in-grain average orientation difference of the grains existing in the tilt angle section outside the range of 0 to 10 degrees is 5 degrees or more. The surface-coated cutting tool according to claim 1.
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|---|---|---|---|---|
| JP2015047643A (en) * | 2013-08-29 | 2015-03-16 | 三菱マテリアル株式会社 | Surface coated cutting tool excellent in chipping resistance |
| JP2015101748A (en) * | 2013-11-22 | 2015-06-04 | 住友電気工業株式会社 | Cemented carbide and surface-coated cutting tool prepared using the same |
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| WO2015111752A1 (en) * | 2014-01-27 | 2015-07-30 | 株式会社タンガロイ | Coated cutting tool |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2015047643A (en) * | 2013-08-29 | 2015-03-16 | 三菱マテリアル株式会社 | Surface coated cutting tool excellent in chipping resistance |
| JP2015101748A (en) * | 2013-11-22 | 2015-06-04 | 住友電気工業株式会社 | Cemented carbide and surface-coated cutting tool prepared using the same |
| JP2015101747A (en) * | 2013-11-22 | 2015-06-04 | 住友電気工業株式会社 | Cemented carbide and surface-coated cutting tool prepared using the same |
| JP2015101746A (en) * | 2013-11-22 | 2015-06-04 | 住友電気工業株式会社 | Cemented carbide and surface-coated cutting tool prepared using the same |
| JP2015101745A (en) * | 2013-11-22 | 2015-06-04 | 住友電気工業株式会社 | Cemented carbide and surface-coated cutting tool prepared using the same |
| WO2015111752A1 (en) * | 2014-01-27 | 2015-07-30 | 株式会社タンガロイ | Coated cutting tool |
| CN105916617A (en) * | 2014-01-27 | 2016-08-31 | 株式会社钨钛合金 | Coated cutting tool |
| US9969007B2 (en) | 2014-01-27 | 2018-05-15 | Tungaloy Corporation | Coated cutting tool |
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