JP2009056537A - Surface-coated cutting tool - Google Patents
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この発明は、大きな発熱を伴うとともに、切刃部に大きな衝撃的・機械的負荷がかかる鋼や鋳鉄などの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 exhibits excellent chipping resistance and wear resistance with a high hard coating layer in high-speed intermittent cutting of steel or cast iron that is accompanied by large heat generation and has a large impact and mechanical load on the cutting edge. The present invention relates to a surface-coated cutting tool (hereinafter referred to as a coated tool).
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)いずれも化学蒸着形成された、TiC層、TiN層、TiCN層、TiCO層、およびTiCNO層のうちの1層以上からなり、かつ0.1〜15μmの合計平均層厚を有する密着性Ti化合物層と、2.5〜15μmの合計平均層厚を有し、かつ、組成式:(Ti1−αCrα)CNで表した場合、原子比で、α:0.005〜0.05を満足するTiとCrの炭窒化物層からなる下部層、
(b)化学蒸着形成され1〜15μmの平均層厚を有するα型のAl2O3層からなる上部層、
以上(a)、(b)で構成された硬質被覆層を備える被覆工具において、
上記(a)のTi化合物層のうちのTiとCrの炭窒化物層を、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、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{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、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45%以上の割合を占める傾斜角度数分布グラフを示すTiとCrの炭窒化物(以下、従来(Ti,Cr)CNで示す)層、
で構成することにより、高速重切削加工ですぐれた耐チッピング性を示すことが知られている。
On the surface of a substrate composed of tungsten carbide (hereinafter referred to as WC) -based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) -based cermet (hereinafter collectively referred to as a tool substrate),
(A) All formed by chemical vapor deposition, comprising one or more of a TiC layer, a TiN layer, a TiCN layer, a TiCO layer, and a TiCNO layer, and having a total average layer thickness of 0.1 to 15 μm When the Ti compound layer has a total average layer thickness of 2.5 to 15 μm and is represented by a composition formula: (Ti 1−α Cr α ) CN, the atomic ratio is α: 0.005 to 0.00. A lower layer composed of a carbonitride layer of Ti and Cr satisfying 05,
(B) an upper layer comprising an α-type Al 2 O 3 layer formed by chemical vapor deposition and having an average layer thickness of 1 to 15 μm;
In a coated tool provided with the hard coating layer comprised by the above (a) and (b),
The Ti and Cr carbonitride layers of the Ti compound layer of (a) above are individually divided into crystal grains having a cubic crystal lattice existing within the measurement range of the surface polished surface using a field emission scanning electron microscope. Irradiate with an electron beam to measure the tilt angle formed by the normal of the {112} plane that is the crystal plane of the crystal grain with respect to the normal of the surface polished surface. In the inclination angle number distribution graph obtained by dividing the measured inclination angle within the range of 45 degrees for each pitch of 0.25 degree and totaling the frequencies existing in each division, it is within the range of 0 to 10 degrees. An inclination angle distribution graph in which the highest peak exists in the inclination angle section and the sum of the frequencies existing in the range of 0 to 10 degrees occupies 45% or more of the entire frequency in the inclination angle distribution graph is shown. Ti and Cr carbonitride (hereinafter, conventional (Ti, C ) Shown in the CN) layer,
It is known that it exhibits excellent chipping resistance in high-speed heavy cutting.
そして、上記従来(Ti,Cr)CNは、
反応ガス組成(容量%):TiCl4:2〜10%、CrCl3:0.01〜0.5%、CH3CN:0.5〜3%、N2:30〜45%、Ar:残り、
反応雰囲気温度:900〜1020℃、
反応雰囲気圧力:6〜20kPa、
の条件で化学蒸着することにより形成されることが知られている。
Reaction gas composition (volume%): TiCl 4 : 2 to 10%, CrCl 3 : 0.01 to 0.5%, CH 3 CN: 0.5 to 3%, N 2 : 30 to 45%, Ar: remaining ,
Reaction atmosphere temperature: 900-1020 ° C.
Reaction atmosphere pressure: 6-20 kPa,
It is known that it is formed by chemical vapor deposition under the following conditions.
近年の切削装置の高性能化はめざましく、一方で切削加工におけ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、上記の従来被覆工具においては、下部層として前記従来(Ti,Cr)CN層、上部層としてAl2O3層が設けられ、そして、下部層である従来(Ti,Cr)CN層が所定の高温強度を有し、上部層のAl2O3層がすぐれた高温硬さを有することから、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、大きな発熱を伴うとともに、切刃部に大きな衝撃的・機械的負荷がかかる鋼や鋳鉄などの高速断続切削加工で用いた場合には、下部層として設けられた前記従来(Ti,Cr)CN層の高温強度が十分であるとはいえないため、機械的衝撃に対して満足に対応することができず、切削加工時の機械的な衝撃力によってチッピングを発生しやすく、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 devices has been remarkably improved. On the other hand, there are strong demands for labor saving and energy saving in cutting, and further cost reduction. In the above conventional coated tool, the conventional (Ti, Cr) CN is used as a lower layer. Al 2 O 3 layer is provided as the upper layer, and the conventional (Ti, Cr) CN layer as the lower layer has a predetermined high temperature strength, and the upper layer Al 2 O 3 layer is excellent in high temperature hardness. Therefore, there is no problem when it is used for continuous cutting and interrupted cutting under normal conditions such as steel and cast iron. When used in high-speed intermittent cutting of steel and cast iron that are subject to mechanical and mechanical loads, the high-temperature strength of the conventional (Ti, Cr) CN layer provided as the lower layer cannot be said to be sufficient. Satisfying mechanical shock The present situation is that it is difficult to respond, chipping is likely to occur due to mechanical impact force during cutting, and the service life is 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と耐摩耗性の向上を図るべく、Ti化合物層のうちの特に従来(Ti,Cr)CN層について研究を行った結果、以下の知見を得た。
(a)従来被覆工具の硬質被覆層において、下部層を構成するTi化合物層のうちの従来(Ti,Cr)CN層は、既に述べたように、例えば、通常の化学蒸着装置にて、
反応ガス組成(容量%):TiCl4:2〜10%、CrCl3:0.01〜0.5%、CH3CN:0.5〜3%、N2:30〜45%、Ar:残り、
反応雰囲気温度:900〜1020℃、
反応雰囲気圧力:6〜20kPa、
の条件で化学蒸着することにより、
組成式:(Ti1−YCrY)CNで表した場合、原子比で、Y:0.005〜0.05、を満足する(Ti,Cr)CN層を形成することができ、この結果の(Ti,Cr)CN層(従来(Ti,Cr)CN層)は、格子点にTi、Cr、炭素(C)、および窒素(N)からなる構成原子がそれぞれ存在するNaCl型面心立方晶の結晶構造を有し、すぐれた高温強度を有すること。
In view of the above, the inventors of the present invention have proposed a conventional (Ti, Cr) CN layer among Ti compound layers in order to improve the chipping resistance and wear resistance of the hard coating layer of the coated tool. As a result of research on the following, the following knowledge was obtained.
(A) In the hard coating layer of the conventional coated tool, the conventional (Ti, Cr) CN layer of the Ti compound layer constituting the lower layer is, for example, as described above, for example, with a normal chemical vapor deposition apparatus.
Reaction gas composition (volume%): TiCl 4 : 2 to 10%, CrCl 3 : 0.01 to 0.5%, CH 3 CN: 0.5 to 3%, N 2 : 30 to 45%, Ar: remaining ,
Reaction atmosphere temperature: 900-1020 ° C.
Reaction atmosphere pressure: 6-20 kPa,
By chemical vapor deposition under the conditions of
When expressed by the composition formula: (Ti 1-Y Cr Y ) CN, a (Ti, Cr) CN layer satisfying Y: 0.005 to 0.05 in atomic ratio can be formed. (Ti, Cr) CN layer (conventional (Ti, Cr) CN layer) is a NaCl-type face-centered cubic in which constituent atoms composed of Ti, Cr, carbon (C), and nitrogen (N) are present at lattice points. It has a crystal structure and has excellent high-temperature strength.
(b)そして、上記(a)の従来(Ti,Cr)CN層は、図1(a),(b)に概略説明図で示されるように、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、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{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、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45%以上の割合を占める傾斜角度数分布グラフを示すこと。 (B) Then, the conventional (Ti, Cr) CN layer of (a) is subjected to surface polishing using a field emission scanning electron microscope, as schematically shown in FIGS. 1 (a) and 1 (b). A method of the {112} plane which is the crystal plane of the crystal grain with respect to the normal line of the surface-polished surface by irradiating an electron beam to each crystal grain having a cubic crystal lattice existing within the measurement range of the plane Measure the tilt angle formed by the line, and divide the measured tilt angles within the range of 0 to 45 degrees out of the measured tilt angles by pitch of 0.25 degrees, and count the frequencies existing in each section In the inclination angle distribution graph, the highest peak exists in the inclination angle section within the range of 0 to 10 degrees, and the total of the frequencies existing within the range of 0 to 10 degrees is the inclination angle number distribution graph. Inclination angle frequency distribution graph that accounts for more than 45% of the total frequency at It.
(c)上記の従来TiCN層の形成に際して、層中のCr含有割合を、上記の通りTiとの合量に占める原子比で0.005〜0.05とすることによって、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45%以上の割合を占めるようになるのであり、したがって、前記従来(Ti,Cr)CN層中のCr含有割合が前記の範囲から低い方に外れても、あるいは高い方に外れても、0〜10度の範囲内に存在する度数の合計は45%未満となってしまい、この場合は高温強度の向上を図ることができないこと。 (C) When forming the conventional TiCN layer, the Cr content ratio in the layer is 0.005 to 0.05 in terms of the atomic ratio to the total amount with Ti as described above, whereby the above 0 to 10 degrees. Therefore, the total of the frequencies existing in the range of 45% occupies a ratio of 45% or more of the entire frequencies in the inclination angle frequency distribution graph. Therefore, the Cr content ratio in the conventional (Ti, Cr) CN layer is Even if it deviates from the above range to the lower side or deviates from the higher side, the total frequency within the range of 0 to 10 degrees becomes less than 45%. In this case, the high temperature strength is improved. What you can't do.
(d)また、通常の蒸着装置にて、
反応ガス組成(容量%):TiCl4:1〜5%、CrCl3:0.7〜2.5%、CH3CN:3〜6%、N2:20〜40%、HCl:0.5〜2%、H2:残り、
反応雰囲気温度:800〜900℃、
反応雰囲気圧力:5〜20kPa、
の条件で化学蒸着を行うと、TiとCrの炭窒化物層が蒸着形成されるが、このTiとCrの炭窒化物層を、
組成式:(Ti1−XCrX)CNで表した場合、原子比で、X:0.12〜0.2を満足するTiとCrの炭窒化物(以下、改質(Ti,Cr)CNで示す)層として表すことができ、そして、この改質(Ti,Cr)CN層は、格子点にTi、Cr、炭素(C)、および窒素(N)からなる構成原子がそれぞれ存在するNaCl型面心立方晶の結晶構造であり、上記の従来(Ti,Cr)CN層と同様の結晶構造を有し、そして、前記従来(Ti,Cr)CN層に比して一段とすぐれた高温強度、高温硬さおよび耐熱性を有すること。
(D) Moreover, in a normal vapor deposition apparatus,
Reaction gas composition (volume%): TiCl 4 : 1 to 5%, CrCl 3 : 0.7 to 2.5%, CH 3 CN: 3 to 6%, N 2 : 20 to 40%, HCl: 0.5 ~2%, H 2: remainder,
Reaction atmosphere temperature: 800 to 900 ° C.
Reaction atmosphere pressure: 5 to 20 kPa,
When chemical vapor deposition is performed under the conditions, Ti and Cr carbonitride layers are formed by vapor deposition.
Compositional formula: (Ti 1-X Cr X ) CN, when expressed in terms of atomic ratio, Ti: Cr carbonitride satisfying X: 0.12-0.2 (hereinafter, modified (Ti, Cr)) This modified (Ti, Cr) CN layer has constituent atoms composed of Ti, Cr, carbon (C), and nitrogen (N) at lattice points, respectively. The crystal structure of the NaCl type face centered cubic crystal has the same crystal structure as that of the conventional (Ti, Cr) CN layer, and a higher temperature than the conventional (Ti, Cr) CN layer. Must have strength, high temperature hardness and heat resistance.
(e)改質(Ti,Cr)CN層について、
電界放出型走査電子顕微鏡を用い、図2(a),(b)に概略説明図で例示される通り、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{111}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、前記改質(Ti,Cr)CN層は、図4に例示される通り、傾斜角区分の特定位置にシャープな最高ピークが現れ、そしてこのような場合に、改質(Ti,Cr)CN層にはクーリングクラックが均一に分散し、これによって、Cr含有量を増加したことによる改質(Ti,Cr)CN層の高温強度の低下を抑えることができると同時にすぐれた高温硬さを保持するようになり、さらに、結晶粒界の安定性が増し、切削加工時に発生した層内クラックの伝播進展が抑制され、切刃部に断続的に衝撃的な負荷が加わった場合にも、耐チッピング性が大幅に改善され、また、耐摩耗性も大幅に向上する。
(E) About the modified (Ti, Cr) CN layer,
Using a field emission scanning electron microscope, as illustrated in the schematic explanatory diagrams of FIGS. 2A and 2B, the electron beam is individually applied to each crystal grain having a cubic crystal lattice existing within the measurement range of the surface polished surface. Is measured with respect to the normal of the surface polished surface, and the tilt angle formed by the normal of the {111} plane that is the crystal plane of the crystal grain is measured. When the measured inclination angle within the range of 0.25 degrees is divided for every pitch of 0.25 degrees and the inclination angle number distribution graph is formed by counting the frequencies existing in each division, the modification (Ti, Cr 4) As shown in FIG. 4, the CN layer has a sharp maximum peak at a specific position in the tilt angle section. In such a case, the modified (Ti, Cr) CN layer has uniform cooling cracks. Dispersion and thereby modification by increasing the Cr content ( i, Cr) The high temperature strength of the CN layer can be suppressed, and at the same time, excellent high temperature hardness can be maintained. Furthermore, the stability of the grain boundary is increased, and the cracks in the layer generated during the cutting process can be reduced. Propagation is suppressed, and even when a shocking load is intermittently applied to the cutting edge, chipping resistance is greatly improved, and wear resistance is also greatly improved.
(f)上記の通り、上記改質(Ti,Cr)CN層の形成に際して、層中のCr含有割合を、Tiとの合量に占める割合(原子比)で0.12〜0.20とすることによって、前記改質(Ti,Cr)CN層の傾斜角度数分布グラフで、{111}面のシャープな最高ピークが傾斜角区分の0〜10度の範囲内に現れ、かつ、前記0〜10度の範囲内に存在する度数割合が、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ようになるのであり、したがって、前記改質(Ti,Cr)CN層中のCr含有割合が前記の範囲から低い方に外れても、あるいは高い方に外れても、傾斜角度数分布グラフにおけるシャープな最高ピークが傾斜角区分の0〜10度の範囲から外れ、かつ、前記0〜10度の範囲内に存在する度数数割合も45%未満になってしまい、この場合は一段の耐熱性向上効果を期待できないばかりか、Cr含有割合を増加したことによる高温強度の低下をクーリングクラックの均一分散によって抑制することはできないこと。
つまり、上記改質(Ti,Cr)CN層のCr成分は、Tiとの合量に占める割合(原子比)で0.12(12原子%)以上で所望の耐熱性向上効果が現れるが、その含有割合が0.20(20原子%)を越えると、高熱発生を伴う高速断続切削加工では、改質(Ti,Cr)CN層は急激に軟化し、熱塑性変形、偏摩耗を生じやすくなることから、その含有割合は、Tiとの合量に占める割合(原子比)で0.12〜0.20とする必要がある。
(F) As described above, when the modified (Ti, Cr) CN layer is formed, the Cr content in the layer is 0.12 to 0.20 in terms of the ratio (atomic ratio) to the total amount with Ti. By doing so, in the inclination angle number distribution graph of the modified (Ti, Cr) CN layer, the sharpest peak of the {111} plane appears in the range of 0 to 10 degrees of the inclination angle section, and the 0 The frequency ratio existing in the range of -10 degrees shows an inclination angle number distribution graph that occupies a ratio of 45% or more of the entire frequency in the inclination angle number distribution graph. Therefore, the modification (Ti, Even if the Cr content ratio in the Cr) CN layer deviates from the above range to the lower or higher range, the sharp maximum peak in the inclination angle number distribution graph is in the range of 0 to 10 degrees of the inclination angle section. And the above 0 to 10 The frequency ratio existing in the range of less than 45%, in this case, not only can not expect a further heat resistance improvement effect, the decrease in high-temperature strength due to the increase of the Cr content ratio is uniform cooling cracks It cannot be suppressed by dispersion.
That is, the Cr component of the modified (Ti, Cr) CN layer has a desired heat resistance improvement effect at a ratio (atomic ratio) of 0.12 (12 atomic%) or more in the total amount with Ti, When the content ratio exceeds 0.20 (20 atomic%), in high-speed intermittent cutting with high heat generation, the modified (Ti, Cr) CN layer softens rapidly, and it is easy to cause thermoplastic deformation and uneven wear. Therefore, the content ratio needs to be 0.12 to 0.20 in a ratio (atomic ratio) to the total amount with Ti.
(g)硬質被覆層の層構造
硬質被覆層は、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層以上からなるTi化合物層と、(Ti,Cr)CN層で構成し、しかも、(Ti,Cr)CN層のうちの少なくとも1層は前記従来(Ti,Cr)CN層であり、また、さらに少なくとも1層は前記改質(Ti,Cr)CN層で構成しなければならない。
既に述べたように、前記従来(Ti,Cr)CN層は高温強度にすぐれるものの、高速断続切削加工において必要とされる十分な耐衝撃性は備えていないが、従来(Ti,Cr)CN層に比して、高温強度、高温硬さおよび耐熱性が優れると同時に、一段とすぐれた耐衝撃性を備えた改質(Ti,Cr)CN層を、硬質被覆層の構成層として設けることによって、硬質被覆層全体としての高温強度を高めると同時に高温硬さを維持することができるので、上記硬質被覆層を蒸着形成した被覆工具は、高速断続切削加工時の耐衝撃性が改善され、その結果として、すぐれた耐チッピング性を示すとともに、長期に亘ってすぐれた耐摩耗性を発揮するようになる。
以上(a)〜(g)に示される研究結果を得たのである。
(G) Layer structure of hard coating layer The hard coating layer is composed of one or more of Ti carbide layer, nitride layer, carbonitride layer, carbonate layer, and carbonitride layer. It is composed of a compound layer and a (Ti, Cr) CN layer, and at least one of the (Ti, Cr) CN layers is the conventional (Ti, Cr) CN layer, and at least one layer is It must be composed of the modified (Ti, Cr) CN layer.
As described above, the conventional (Ti, Cr) CN layer is excellent in high-temperature strength, but does not have sufficient impact resistance required in high-speed intermittent cutting, but the conventional (Ti, Cr) CN is not provided. By providing a modified (Ti, Cr) CN layer as a constituent layer of the hard coating layer, which has superior high-temperature strength, high-temperature hardness and heat resistance as compared to the layer, and at the same time, excellent impact resistance Since the high-temperature strength of the hard coating layer as a whole can be increased and at the same time the high-temperature hardness can be maintained, the coated tool formed by vapor deposition of the hard coating layer has improved impact resistance during high-speed intermittent cutting, As a result, it exhibits excellent chipping resistance and exhibits excellent wear resistance over a long period of time.
The research results shown in (a) to (g) above were obtained.
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、4〜20μmの合計平均層厚を有する硬質被覆層として、少なくとも、Ti化合物層とTiとCrの炭窒化物層とを蒸着形成した表面被覆切削工具において、
(a)Ti化合物層は、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、
(b)上記TiとCrの炭窒化物層のうちの少なくとも1層は、2〜15μmの平均層厚を有し、かつ、
組成式:(Ti1−XCrX)CNで表した場合、原子比で、X:0.12〜0.2を満足するTiとCrの炭窒化物層であり、
さらに、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、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{111}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、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45%以上の割合を占める傾斜角度数分布グラフを示すTiとCrの炭窒化物層で形成され、
(c)また、上記TiとCrの炭窒化物層のうちのさらに少なくとも1層は、2〜15μmの平均層厚を有し、かつ、
組成式:(Ti1−YCrY)CNで表した場合、原子比で、Y:0.005〜0.05を満足するTiとCrの炭窒化物層であり、
さらに、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、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{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、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45%以上の割合を占める傾斜角度数分布グラフを示すTiとCrの炭窒化物層で形成されている、
ことを特徴とする表面被覆切削工具(被覆工具)。
(2) 前記4〜20μmの合計平均層厚を有する硬質被覆層の表面に、さらに、1〜15μmの平均層厚の酸化アルミニウム層を蒸着形成したことを特徴とする、前記(1)記載の表面被覆切削工具(被覆工具)。」
に特徴を有するものである。
This invention was made based on the above research results,
“(1) At least a Ti compound layer, Ti and Cr as a hard coating layer having a total average layer thickness of 4 to 20 μm on the surface of a tool base made of tungsten carbide-based cemented carbide or titanium carbonitride-based cermet In the surface-coated cutting tool formed by vapor deposition of the carbonitride layer of
(A) The Ti compound layer is composed of one or more of a Ti carbide layer, a nitride layer, a carbonitride layer, a carbonate layer, and a carbonitride layer,
(B) At least one of the Ti and Cr carbonitride layers has an average layer thickness of 2 to 15 μm, and
When represented by composition formula: (Ti 1-X Cr X ) CN, it is a carbonitride layer of Ti and Cr that satisfies X: 0.12-0.2 in atomic ratio,
Further, by using a field emission scanning electron microscope, each crystal grain having a cubic crystal lattice existing within the measurement range of the surface polishing surface is irradiated with an electron beam, and the normal line of the surface polishing surface is The inclination angle formed by the normal line of the {111} plane, which is the crystal plane of the crystal grain, is measured, and the measurement inclination angle within the range of 0 to 45 degrees out of the measurement inclination angles is set every pitch of 0.25 degrees. In the inclination angle number distribution graph obtained by summing up the frequencies existing in each section, the highest peak is present in the inclination angle section in the range of 0 to 10 degrees, and within the range of 0 to 10 degrees. Is formed by a carbonitride layer of Ti and Cr showing an inclination angle distribution graph occupying a ratio of 45% or more of the entire frequency in the inclination angle distribution graph,
(C) Further, at least one of the Ti and Cr carbonitride layers has an average layer thickness of 2 to 15 μm, and
When represented by a composition formula: (Ti 1-Y Cr Y ) CN, it is a carbonitride layer of Ti and Cr satisfying Y: 0.005 to 0.05 in atomic ratio,
Further, by using a field emission scanning electron microscope, each crystal grain having a cubic crystal lattice existing within the measurement range of the surface polishing surface is irradiated with an electron beam, and the normal line of the surface polishing surface is The inclination angle formed by the normal of the {112} plane, which is the crystal plane of the crystal grain, is measured, and the measurement inclination angle within the range of 0 to 45 degrees out of the measurement inclination angles is set every pitch of 0.25 degrees. In the slope angle distribution graph formed by summing up the frequencies existing in each section, the highest peak exists in the slope angle section in the range of 0 to 10 degrees, and within the range of 0 to 10 degrees. Is formed of Ti and Cr carbonitride layers showing an inclination angle distribution graph that occupies a ratio of 45% or more of the entire frequencies in the inclination angle distribution graph.
A surface-coated cutting tool (coated tool).
(2) The aluminum oxide layer having an average layer thickness of 1 to 15 μm is further formed on the surface of the hard coating layer having a total average layer thickness of 4 to 20 μm by vapor deposition. Surface coated cutting tool (coated tool). "
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、上記の通りに数値限定した理由を以下に説明する。 Next, the reason why the constituent layers of the hard coating layer of the coated tool of the present invention are numerically limited as described above will be described below.
(a)Ti化合物層
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からなる硬質被覆層としてのTi化合物層は、それ自体が所定の高温強度を有し、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、工具基体と従来(Ti,Cr)CN層あるいは改質(Ti,Cr)CN層のいずれとも強固に密着し、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4μm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、断続切削加工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、Ti化合物層の合計平均層厚を4〜20μmと定めた。
(A) Ti compound layer The Ti compound layer as a hard coating layer composed of a Ti carbide layer, a nitride layer, a carbonitride layer, a carbonate layer, and a carbonitride oxide layer itself has a predetermined high-temperature strength. In addition to the hard coating layer having high-temperature strength due to the presence thereof, the tool base and the conventional (Ti, Cr) CN layer or the modified (Ti, Cr) CN layer are firmly adhered to each other. Although it has the effect | action which contributes to the adhesive improvement with respect to the tool base | substrate of a hard coating layer, if the total average layer thickness is less than 4 micrometers, the said effect cannot fully be exhibited, On the other hand, the total average layer thickness exceeds 20 micrometers Then, it becomes easy to cause thermoplastic deformation by intermittent cutting, and this causes uneven wear. Therefore, the total average layer thickness of the Ti compound layer was determined to be 4 to 20 μm.
(b)従来(Ti,Cr)CN層
従来(Ti,Cr)CN層については、上記の通り、層中のCr含有割合(Y値)をTiとの合量に占める原子比で、0.005〜0.05とすることによって、{112}面の法線がなす傾斜角を集計してなる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、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45%以上の割合を占め、かつ、すぐれた高温強度を具備する従来(Ti,Cr)CN層を蒸着形成することができるが、その平均層厚が2μm未満では所望のすぐれた高温強度向上効果を発揮することができず、一方その平均層厚が15μmを越えると、偏摩耗の原因となる熱塑性変形が発生し易くなり、摩耗が加速するようになることから、その平均層厚を2〜15μmと定めた。
(B) Conventional (Ti, Cr) CN layer As described above, the conventional (Ti, Cr) CN layer has an atomic ratio of the Cr content (Y value) in the layer to the total amount of Ti. By setting 005 to 0.05, in the inclination angle number distribution graph obtained by adding up the inclination angles formed by the normal of the {112} plane, the highest peak exists in the inclination angle section within the range of 0 to 10 degrees. In addition, the total of the frequencies existing in the range of 0 to 10 degrees occupies a ratio of 45% or more of the entire frequencies in the inclination angle frequency distribution graph and has a high temperature strength (Ti, Cr). Although the CN layer can be formed by vapor deposition, if the average layer thickness is less than 2 μm, the desired excellent high-temperature strength improvement effect cannot be exhibited. On the other hand, if the average layer thickness exceeds 15 μm, it causes uneven wear. The thermoplastic deformation that becomes , From becoming so worn accelerates, it determined the average layer thickness and 2 to 15 [mu] m.
(c)改質(Ti,Cr)CN層
Ti化合物層のうちの改質(Ti,Cr)CN層については、層中のCr含有割合(X値)をTiとの合量に占める原子比で、0.12〜0.2とすることによって、{111}面の法線がなす傾斜角を集計してなる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、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45%以上の割合を占める改質(Ti,Cr)CN層を形成することができ、そして、このような改質(Ti,Cr)CN層は、クーリングクラックが均一に分散し、これによって、Cr含有量を増加したことによる改質(Ti,Cr)CN層の高温強度の低下を抑えることができると同時にすぐれた高温硬さを保持するようになり、さらに、結晶粒界の安定性が増し、切削加工時に発生した層内クラックの伝播進展が抑制され、切刃部に断続的に衝撃的な負荷が加わった場合にも、耐チッピング性が大幅に改善され、また、耐摩耗性の向上も図れる。
したがって、その含有割合が0.12未満でも、0.2を越えても、高温硬さと耐熱性の向上効果を期待することができないばかりか、高温強度の低下をクーリングクラックの均一分散により抑えることができなくなるため、断続的な繰り返しの衝撃的負荷がかかる断続切削加工においては、熱塑性変形あるいは偏摩耗の発生等によって耐摩耗性の劣ったものとなる。
そして、従来(Ti,Cr)CNの場合と同様に、その平均層厚が2μm未満では所望のすぐれた高温強度向上効果を発揮することができず、一方その平均層厚が15μmを越えると、偏摩耗の原因となる熱塑性変形が発生し易くなり、摩耗が加速するようになることから、その平均層厚を2〜15μmと定めた。
(C) Modified (Ti, Cr) CN layer For the modified (Ti, Cr) CN layer of the Ti compound layer, the atomic ratio of the Cr content ratio (X value) in the layer to the total amount of Ti In the inclination angle number distribution graph obtained by adding up the inclination angles formed by the normal lines of the {111} plane by setting to 0.12 to 0.2, the inclination angle section within the range of 0 to 10 degrees is the highest. A modified (Ti, Cr) CN layer is formed in which a peak is present and the total frequency within the range of 0 to 10 degrees occupies 45% or more of the total frequency in the gradient angle distribution graph. And such a modified (Ti, Cr) CN layer has a high temperature of the modified (Ti, Cr) CN layer due to the uniform distribution of cooling cracks, thereby increasing the Cr content. It is possible to suppress a decrease in strength and at the same time excellent In addition, the stability of the grain boundaries is increased, the propagation of cracks in the layer generated during cutting is suppressed, and an intermittent impact load is applied to the cutting edge. In this case, the chipping resistance can be greatly improved and the wear resistance can be improved.
Therefore, even if the content ratio is less than 0.12 or exceeds 0.2, not only the improvement effect of high temperature hardness and heat resistance can be expected, but also the decrease in high temperature strength is suppressed by uniform dispersion of cooling cracks. Therefore, in the intermittent cutting process in which an intermittent and repeated impact load is applied, the wear resistance is inferior due to the occurrence of thermoplastic deformation or uneven wear.
And, as in the case of conventional (Ti, Cr) CN, if the average layer thickness is less than 2 μm, the desired excellent high-temperature strength improvement effect cannot be exhibited, while if the average layer thickness exceeds 15 μm, The average layer thickness was determined to be 2 to 15 μm because thermoplastic deformation that causes uneven wear tends to occur and wear accelerates.
なお、従来(Ti,Cr)CN層および改質(Ti,Cr)CN層におけるTi、Cr以外の構成成分であるCとNについて言えば、C成分には層の硬さを向上させ、また、N成分には高温強度を向上させる作用があり、これら両成分を共存含有することにより高い硬さとすぐれた強度を具備する炭窒化物層となるのであり、したがって、層中のN成分の含有割合がC成分との合量に占める割合(=N/(C+N))で0.35未満(但し、原子比)では所望の強度を確保することができず、一方、その含有割合が0.55を越えると、相対的にC成分の含有割合が少なくなり過ぎて、所望の高硬度が得られなくなることから、従来(Ti,Cr)CN層および改質(Ti,Cr)CN層におけるC成分との合量に対するN成分の含有割合(=N/(C+N))は、原子比で0.35〜0.55とすることが望ましい。 Regarding C and N, which are constituent components other than Ti and Cr in the conventional (Ti, Cr) CN layer and modified (Ti, Cr) CN layer, the C component improves the hardness of the layer, and The N component has the effect of improving the high-temperature strength, and by coexisting both these components, it becomes a carbonitride layer having high hardness and excellent strength. Therefore, the inclusion of the N component in the layer If the ratio is less than 0.35 (provided that the atomic ratio) is the ratio of the total amount with the C component (= N / (C + N)), the desired strength cannot be ensured. If it exceeds 55, the content ratio of the C component becomes relatively small and the desired high hardness cannot be obtained. Therefore, the C in the conventional (Ti, Cr) CN layer and the modified (Ti, Cr) CN layer Content ratio of N component to total amount with component ( N / (C + N)) is preferably set to 0.35 to 0.55 in atomic ratio.
(d)硬質被覆層の層構造
硬質被覆層は、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少なくとも2層以上からなるTi化合物層と、(Ti,Cr)CN層で構成し、しかも、(Ti,Cr)CN層のうちの少なくとも1層は前記従来(Ti,Cr)CN層であり、また、さらに少なくとも1層は前記改質(Ti,Cr)CN層で構成しなければならない。
既に述べたように、前記従来(Ti,Cr)CN層は高温強度にすぐれるものの、高速断続切削加工において必要とされる十分な耐衝撃性を備えているとはいえないので、高温強度、高温硬さおよび耐熱性に優れると同時に、一段とすぐれた耐衝撃性を備えた改質(Ti,Cr)CN層を、硬質被覆層の構成層として設けることによって、硬質被覆層の高温強度を高めると同時に高温硬さを維持することができ、さらに、Ti化合物層、改質(Ti,Cr)CN層、従来(Ti,Cr)CN層は、相互に層間の密着強度も高いため、硬質被覆層全体としての高温強度がさらに一層高まり、その結果、本発明の被覆工具は、各種の鋼や鋳鉄の高速断続切削加工時の耐衝撃性が改善され、その結果として、すぐれた耐チッピング性を示すとともに、長期に亘ってすぐれた耐摩耗性を発揮するようになる。
(D) Layer structure of hard coating layer The hard coating layer is a Ti compound layer comprising at least two of a Ti carbide layer, a nitride layer, a carbonitride layer, a carbonate layer, and a carbonitride layer. And at least one of the (Ti, Cr) CN layers is the conventional (Ti, Cr) CN layer, and at least one of the modified layers is the modified (Ti, Cr) CN layer. It must be composed of a quality (Ti, Cr) CN layer.
As already described, although the conventional (Ti, Cr) CN layer is excellent in high-temperature strength, it cannot be said to have sufficient impact resistance required in high-speed interrupted cutting, so high-temperature strength, The high temperature strength of the hard coating layer is increased by providing a modified (Ti, Cr) CN layer with excellent impact resistance at the same time as high temperature hardness and heat resistance as a constituent layer of the hard coating layer. At the same time, the high temperature hardness can be maintained, and the Ti compound layer, the modified (Ti, Cr) CN layer, and the conventional (Ti, Cr) CN layer have high adhesion strength to each other, so that they are hard-coated. As a result, the high-temperature strength of the entire layer is further increased, and as a result, the coated tool of the present invention has improved impact resistance during high-speed intermittent cutting of various steels and cast irons, resulting in excellent chipping resistance. With showing So to exert excellent wear resistance for a long time.
なお、硬質被覆層としてAl2O3層を設けることによって、被覆工具の耐摩耗性を改善することは良く知られているが、本発明においても、硬質被覆層の最表面に、さらに、Al2O3層を蒸着被覆することにより、被覆工具の耐摩耗性のより一層の改善を図ることもできる。その際、Al2O3層としては、α型Al2O3層、κ型Al2O3層等種々の結晶構造のAl2O3層が知られているが、これらの結晶構造のいずのAl2O3層を被覆しても良く、その結晶構造が特に限定されるものではない。
ただ、Al2O3層を蒸着被覆する場合に、その平均層厚が1μm未満では、硬質被覆層のさらなる耐摩耗性向上を期待することはできず、一方、その平均層厚が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、その平均層厚は1〜15μmとすることが望ましい。
Although it is well known that the wear resistance of the coated tool is improved by providing an Al 2 O 3 layer as the hard coating layer, in the present invention, Al is further provided on the outermost surface of the hard coating layer. The wear resistance of the coated tool can be further improved by vapor deposition coating of the 2 O 3 layer. At that time, the the Al 2 O 3 layer, alpha type the Al 2 O 3 layer, but the Al 2 O 3 layer of κ type the Al 2 O 3 layer such various crystal structures are known, have these crystal structures The remaining Al 2 O 3 layer may be coated, and its crystal structure is not particularly limited.
However, when the Al 2 O 3 layer is deposited by vapor deposition, if the average layer thickness is less than 1 μm, further improvement in wear resistance of the hard coating layer cannot be expected, while the average layer thickness exceeds 15 μm. If the thickness is too thick, chipping is likely to occur. Therefore, the average layer thickness is preferably 1 to 15 μm.
また、例えば、切削工具の使用前後の識別を目的として、必要に応じ、黄金色の色調を有するTiN層を最表面層として蒸着形成することもできるが、識別効果という点から、TiN層の平均層厚は0.1〜1μmで十分である。 In addition, for example, for the purpose of identification before and after the use of the cutting tool, a TiN layer having a golden color tone can be vapor-deposited as the outermost surface layer as necessary. A layer thickness of 0.1 to 1 μm is sufficient.
この発明の被覆工具は、高熱発生を伴うとともに、断続的に大きな衝撃的・機械的な負荷が繰り返しかかる各種の鋼や鋳鉄などの高速断続切削でも、硬質被覆層の少なくとも1層が従来(Ti,Cr)CN層で構成されているためすぐれた高温強度を有し、また、さらに少なくとも1層が改質(Ti,Cr)CN層で構成されているため、一段とすぐれた高温強度、耐熱性と高温硬さを発揮し、その結果として、硬質被覆層は長期に亘ってすぐれた耐チッピング性とすぐれた耐摩耗性を示すようになる。 The coated tool according to the present invention has a conventional hard coating layer (Ti) even in high-speed intermittent cutting of various steels and cast irons that are accompanied by high heat generation and repeatedly repeatedly subjected to large impact and mechanical loads. , Cr) CN layer has excellent high temperature strength, and at least one layer is composed of a modified (Ti, Cr) CN layer, which further improves high temperature strength and heat resistance. As a result, the hard coating layer exhibits excellent chipping resistance and excellent wear resistance over a long period of time.
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0.3〜3μm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、Cr3C2粉末、TiN粉末、TaN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32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・CNMG120412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。 WC powder, TiC powder, ZrC powder, VC powder, TaC powder, NbC powder, Cr 3 C 2 powder, TiN powder, TaN powder and Co powder all having an average particle size of 0.3 to 3 μm as raw material powder These raw material powders are blended in the blending composition shown in Table 1, and then added with wax, ball milled in acetone for 32 hours, dried under reduced pressure, and then pressed into a green compact with a predetermined shape at a pressure of 98 MPa. The green compact was press-molded and 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 portion had R: 0.07 mm. The tool bases A to F made of a WC-base cemented carbide having a throwaway tip shape specified in ISO · CNMG12041 were manufactured by performing the honing process.
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32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:0.09mm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。 Further, as raw material powders, TiCN (mass ratio, TiC / TiN = 50/50) powder, Mo 2 C powder, ZrC powder, NbC powder, TaC powder, WC, all having an average particle diameter of 0.5 to 2 μm. Prepare powder, Co powder, and Ni powder, blend these raw material powders into the composition shown in Table 2, wet mix for 32 hours with a ball mill, dry, and press-mold into green compact at 98 MPa pressure Then, this green compact is sintered in a nitrogen atmosphere of 1.3 kPa at a temperature of 1540 ° C. for 1 hour, and after sintering, the cutting edge portion is subjected to a honing process of R: 0.09 mm. Tool bases a to f made of TiCN-based cermet having a chip shape conforming to ISO standards / CNMG 120212 were formed.
つぎに、これらの工具基体A〜Fおよび工具基体a〜fの表面に、通常の化学蒸着装置を用い、硬質被覆層としてTi化合物層、従来(Ti,Cr)CN層、改質(Ti,Cr)CN層)を表3、表4、表5に示される条件で、表6に示される組み合わせおよび目標層厚で蒸着形成し、さらに、その表面に、表3に示される条件かつ表6に示される目標層厚でAl2O3層を蒸着形成することにより本発明被覆工具1〜13を製造した。
Next, a normal chemical vapor deposition apparatus is used on the surfaces of the tool bases A to F and the tool bases a to f, and a Ti compound layer, a conventional (Ti, Cr) CN layer, a modified (Ti, Cr) CN layer) is formed by vapor deposition under the conditions shown in Table 3, Table 4, and Table 5 with the combinations and target layer thicknesses shown in Table 6, and further, the conditions shown in Table 3 and Table 6 are formed on the surface. The
また、比較の目的で、硬質被覆層としてTi化合物層、従来(Ti,Cr)CN層を表3、表4に示される条件で、表7に示される組み合わせおよび目標層厚で蒸着形成し、さらに、その表面に、表3に示される条件かつ表7に示される目標層厚でAl2O3層を蒸着形成することにより比較被覆工具1〜13を製造した。
For comparison purposes, a Ti compound layer as a hard coating layer and a conventional (Ti, Cr) CN layer are vapor-deposited with the combinations and target layer thicknesses shown in Table 7 under the conditions shown in Tables 3 and 4. Furthermore, comparative
ついで、上記の本発明被覆工具および比較被覆工具の硬質被覆層を構成する従来(Ti,Cr)CN層について、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、上記の従来(Ti,Cr)CN層の表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、前記表面研磨面の法線に対して、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。
次に、本発明被覆工具の硬質被覆層を構成する改質(Ti,Cr)CN層について、前記と同様に、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、上記改質(Ti,Cr)CN層の表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、前記表面研磨面の法線に対して、前記結晶粒の結晶面である{111}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。
さらに、比較被覆工具の硬質被覆層を構成する従来(Ti,Cr)CN層については、参考のために、その{111}面の0〜10度の範囲内にある最高ピークの度数割合を上記と同様に測定した。
Next, an inclination angle number distribution graph was created for each of the conventional (Ti, Cr) CN layers constituting the hard coating layer of the above-described coated tool of the present invention and the comparative coated tool using a field emission scanning 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 surface of the conventional (Ti, Cr) CN layer as a polished surface, and 70 ° on the polished surface. An electron backscatter diffraction imaging apparatus is irradiated by irradiating an electron beam with an acceleration voltage of 15 kV at an incident angle of 1 nA with an irradiation current of 1 nA on each crystal grain having a cubic crystal lattice existing within the measurement range of the surface polished surface. Using a 30 × 50 μm region at an interval of 0.1 μm / step, 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 polished surface. Based on this measurement result, among the measured tilt angles, the measured tilt angles within the range of 0 to 45 degrees are divided for each pitch of 0.25 degrees, and the frequencies existing in each section are tabulated. Created by.
Next, as for the modified (Ti, Cr) CN layer constituting the hard coating layer of the coated tool of the present invention, a gradient angle number distribution graph was created using a field emission scanning electron microscope in the same manner as described above.
That is, the modified (Ti, Cr) CN layer is set in a lens barrel of a field emission scanning electron microscope in a state where the surface is a polished surface, and an acceleration voltage of 15 kV is applied to the polished surface at an incident angle of 70 degrees. Is irradiated with an electron current of 1 nA to each crystal grain having a cubic crystal lattice existing within the measurement range of the surface polished surface, and an electron backscatter diffraction image apparatus is used to form a 30 × 50 μm region. At an interval of 0.1 μm / step, an inclination angle formed by a normal line of the {111} plane that is a crystal plane of the crystal grain is measured with respect to a normal line of the surface polished surface, and based on the measurement result, Among the measured inclination angles, the measurement inclination angles in the range of 0 to 45 degrees were divided for each pitch of 0.25 degrees, and the frequency existing in each section was totaled.
Furthermore, for the conventional (Ti, Cr) CN layer constituting the hard coating layer of the comparative coated tool, the frequency ratio of the highest peak within the range of 0 to 10 degrees on the {111} plane is described above for reference. Was measured in the same manner.
上記により求めた従来(Ti,Cr)CN層の{112}面の最高ピークの度数割合、および、改質(Ti,Cr)CN層の{111}面の最高ピークの度数割合を、表6,7にそれぞれ示した(なお、参考のため、表7には、従来(Ti,Cr)CN層の{111}面の最高ピークの度数割合も示す)。 Table 6 shows the frequency ratio of the highest peak of the {112} plane of the conventional (Ti, Cr) CN layer and the peak ratio of the highest peak of the {111} plane of the modified (Ti, Cr) CN layer. (For reference, Table 7 also shows the frequency ratio of the highest peak of the {111} plane of the conventional (Ti, Cr) CN layer).
表6に示されるとおり、本発明被覆工具1〜13の従来(Ti,Cr)CN層の{112}面の最高ピークの度数割合、また、本発明被覆工具1〜13の改質(Ti,Cr)CN層の{111}面の最高ピークの度数割合はいずれも45%以上を示している。
これに対して、表7に示されるように、比較被覆工具1〜13の従来(Ti,Cr)CN層の{112}面の最高ピークの度数割合は45%以上を示しているものの、従来(Ti,Cr)CN層の{111}面の最高ピークの度数割合はいずれも45%未満の値となっている。
As shown in Table 6, the frequency ratio of the highest peak of the {112} plane of the conventional (Ti, Cr) CN layer of the present coated
On the other hand, as shown in Table 7, although the frequency ratio of the highest peak of the {112} plane of the conventional (Ti, Cr) CN layer of the comparative coated
さらに、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、これの硬質被覆層の構成層を電子線マイクロアナライザー(EPMA)およびオージェ分光分析装置を用いて観察(層の縦断面を観察)したところ、前者は目標組成と実質的に同じ組成を有するTi化合物層と、従来(Ti,Cr)CN層および改質(Ti,Cr)CN層からなり、後者についても目標組成と実質的に同じ組成を有するTi化合物層と従来(Ti,Cr)CN層とからなることが確認された。また、これらの被覆工具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(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。なお、硬質被覆層として、さらにAl2O3層を被覆した被覆工具においても、Al2O3層は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, for the above-described
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および比較被覆工具1〜13について、
被削材:JIS・SCM440の長さ方向等間隔4本縦溝入り丸棒、
切削速度: 400 m/min、
切り込み: 1.5 mm、
送り: 0.3 mm/rev、
切削時間: 8 分、
の条件(切削条件Aという)での合金鋼の湿式断続高速切削試験(通常の切削速度は、250m/min)、
被削材:JIS・S45Cの長さ方向等間隔4本縦溝入り丸棒、
切削速度: 400 m/min、
切り込み: 1.5 mm、
送り: 0.35 mm/rev、
切削時間: 10 分、
の条件(切削条件Bという)での炭素鋼の湿式断続高速切削試験(通常の切削速度は、300m/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: 400 m/min、
切り込み: 1.5 mm、
送り: 0.25 mm/rev、
切削時間: 8 分、
の条件(切削条件Cという)でのダクタイル鋳鉄の湿式断続高速切削試験(通常の切削速度は、250m/min)、
を行い、
いずれの切削試験(水溶性切削油使用)でも切刃の逃げ面摩耗幅を測定した。この測定結果を表8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
Work material: JIS · SCM440 lengthwise equidistant 4 vertical grooved round bar,
Cutting speed: 400 m / min,
Cutting depth: 1.5 mm,
Feed: 0.3 mm / rev,
Cutting time: 8 minutes,
Wet intermittent high-speed cutting test (normal cutting speed is 250 m / min) of alloy steel under the above conditions (referred to as cutting condition A),
Work material: JIS · S45C lengthwise equal 4 round grooved round bars,
Cutting speed: 400 m / min,
Cutting depth: 1.5 mm,
Feed: 0.35 mm / rev,
Cutting time: 10 minutes,
Wet intermittent high-speed cutting test (normal cutting speed is 300 m / min) of carbon steel under the conditions (referred to as cutting condition B),
Work material: JIS / FCD450 lengthwise equidistant round bars with 4 vertical grooves,
Cutting speed: 400 m / min,
Cutting depth: 1.5 mm,
Feed: 0.25 mm / rev,
Cutting time: 8 minutes,
Wet intermittent high-speed cutting test of ductile cast iron under the above conditions (referred to as cutting condition C) (normal cutting speed is 250 m / min),
And
In any cutting test (using water-soluble cutting oil), the flank wear width of the cutting edge was measured. The measurement results are shown in Table 8.
表6〜8に示される結果から、本発明被覆工具1〜13は、いずれも硬質被覆層の従来(Ti,Cr)CN層の{112}面の最高ピークの度数割合が45%以上であり、これが一段とすぐれた高温強度を有し、さらに、改質(Ti,Cr)CN層の{111}面の最高ピークの度数割合が45%以上を示し、これがすぐれた高温強度、高温硬さおよび耐熱性を有することから、大きな発熱を伴うとともに、繰り返し大きな衝撃的・機械的負荷がかかる各種の鋼や鋳鉄の高速断続切削加工でも、硬質被覆層が一段とすぐれた高温強度と高温硬さおよび耐熱性を具備し、その結果として、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のに対して、硬質被覆層が改質(Ti,Cr)CN層を備えない従来被覆工具1〜13は、高速断続切削加工において、硬質被覆層の高温強度、耐熱性が不足し、硬質被覆層にチッピングが発生したり、あるいは、熱塑性変形の発生、偏摩耗の発生等により、硬質被覆層の耐摩耗性は非常に劣ったものとなり、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 6 to 8, all of the present coated
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、大きな発熱を伴うとともに、切刃部に大きな衝撃的・機械的負荷がかかる高速断続切削加工でも硬質被覆層がすぐれた耐チッピング性、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 is not only continuous and intermittent cutting under normal conditions such as various steels and cast irons, but also generates a large amount of heat and has a large impact and mechanical load on the cutting edge. Even in high-speed intermittent cutting, the hard coating layer exhibits excellent chipping resistance and wear resistance, and exhibits excellent cutting performance over a long period of time. It can respond satisfactorily to the reduction in cost, energy saving, and cost reduction.
Claims (2)
(a)Ti化合物層は、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、
(b)上記TiとCrの炭窒化物層のうちの少なくとも1層は、2〜15μmの平均層厚を有し、かつ、
組成式:(Ti1−XCrX)CNで表した場合、原子比で、X:0.12〜0.2を満足するTiとCrの炭窒化物層であり、
さらに、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、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{111}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、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45%以上の割合を占める傾斜角度数分布グラフを示すTiとCrの炭窒化物層で形成され、
(c)また、上記TiとCrの炭窒化物層のうちのさらに少なくとも1層は、2〜15μmの平均層厚を有し、かつ、
組成式:(Ti1−YCrY)CNで表した場合、原子比で、Y:0.005〜0.05を満足するTiとCrの炭窒化物層であり、
さらに、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、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{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、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45%以上の割合を占める傾斜角度数分布グラフを示すTiとCrの炭窒化物層で形成されている、
ことを特徴とする表面被覆切削工具。 At least a Ti compound layer and Ti and Cr carbonitride as a hard coating layer having a total average layer thickness of 4 to 20 μm on the surface of the tool base composed of tungsten carbide base cemented carbide or titanium carbonitride base cermet In a surface-coated cutting tool in which a material layer is formed by vapor deposition,
(A) The Ti compound layer is composed of one or more of a Ti carbide layer, a nitride layer, a carbonitride layer, a carbonate layer, and a carbonitride layer,
(B) At least one of the Ti and Cr carbonitride layers has an average layer thickness of 2 to 15 μm, and
When represented by composition formula: (Ti 1-X Cr X ) CN, it is a carbonitride layer of Ti and Cr that satisfies X: 0.12-0.2 in atomic ratio,
Further, by using a field emission scanning electron microscope, each crystal grain having a cubic crystal lattice existing within the measurement range of the surface polishing surface is irradiated with an electron beam, and the normal line of the surface polishing surface is The inclination angle formed by the normal line of the {111} plane, which is the crystal plane of the crystal grain, is measured, and the measurement inclination angle within the range of 0 to 45 degrees out of the measurement inclination angles is set every pitch of 0.25 degrees. In the inclination angle number distribution graph obtained by summing up the frequencies existing in each section, the highest peak is present in the inclination angle section in the range of 0 to 10 degrees, and within the range of 0 to 10 degrees. Is formed by a carbonitride layer of Ti and Cr showing an inclination angle distribution graph occupying a ratio of 45% or more of the entire frequency in the inclination angle distribution graph,
(C) Further, at least one of the Ti and Cr carbonitride layers has an average layer thickness of 2 to 15 μm, and
When represented by a composition formula: (Ti 1-Y Cr Y ) CN, it is a carbonitride layer of Ti and Cr satisfying Y: 0.005 to 0.05 in atomic ratio,
Further, by using a field emission scanning electron microscope, each crystal grain having a cubic crystal lattice existing within the measurement range of the surface polishing surface is irradiated with an electron beam, and the normal line of the surface polishing surface is The inclination angle formed by the normal of the {112} plane, which is the crystal plane of the crystal grain, is measured, and the measurement inclination angle within the range of 0 to 45 degrees out of the measurement inclination angles is set every pitch of 0.25 degrees. In the inclination angle number distribution graph obtained by summing up the frequencies existing in each section, the highest peak is present in the inclination angle section in the range of 0 to 10 degrees, and within the range of 0 to 10 degrees. Is formed of Ti and Cr carbonitride layers showing an inclination angle distribution graph that occupies a ratio of 45% or more of the entire frequency in the inclination angle distribution graph.
A surface-coated cutting tool characterized by that.
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WO2023162682A1 (en) * | 2022-02-28 | 2023-08-31 | 京セラ株式会社 | Coated tool and cutting tool |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
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JPH07100701A (en) * | 1993-05-31 | 1995-04-18 | Sumitomo Electric Ind Ltd | Coated cutting tool and its manufacture |
JPH07173608A (en) * | 1993-12-17 | 1995-07-11 | Toshiba Tungaloy Co Ltd | Wear resistant coated member |
JPH07305181A (en) * | 1994-05-09 | 1995-11-21 | Hitachi Tool Eng Ltd | Coated cemented carbide |
JPH0890310A (en) * | 1994-09-19 | 1996-04-09 | Mitsubishi Materials Corp | Surface coat cutting tool |
JPH0890311A (en) * | 1994-09-19 | 1996-04-09 | Mitsubishi Materials Corp | Composite head layer surface coat cutting tool |
JP2006334710A (en) * | 2005-06-01 | 2006-12-14 | Mitsubishi Materials Corp | Surface coated cermet cutting tool whose hard coating layer exhibits high chipping resistance in high-speed heavy cutting operation |
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2007
- 2007-08-31 JP JP2007225371A patent/JP5019258B2/en not_active Expired - Fee Related
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH07100701A (en) * | 1993-05-31 | 1995-04-18 | Sumitomo Electric Ind Ltd | Coated cutting tool and its manufacture |
JPH07173608A (en) * | 1993-12-17 | 1995-07-11 | Toshiba Tungaloy Co Ltd | Wear resistant coated member |
JPH07305181A (en) * | 1994-05-09 | 1995-11-21 | Hitachi Tool Eng Ltd | Coated cemented carbide |
JPH0890310A (en) * | 1994-09-19 | 1996-04-09 | Mitsubishi Materials Corp | Surface coat cutting tool |
JPH0890311A (en) * | 1994-09-19 | 1996-04-09 | Mitsubishi Materials Corp | Composite head layer surface coat cutting tool |
JP2006334710A (en) * | 2005-06-01 | 2006-12-14 | Mitsubishi Materials Corp | Surface coated cermet cutting tool whose hard coating layer exhibits high chipping resistance in high-speed heavy cutting operation |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2023162682A1 (en) * | 2022-02-28 | 2023-08-31 | 京セラ株式会社 | Coated tool and cutting tool |
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