Coated Cutting Tools

Abstract

The present invention relates to a coated cutting tool (1) comprising a substrate (5) and a coating (6), the coating (6) being Ti 1-x Al x N, a first nanolayer (9) where x is 0.35≦x≦0.70, and Ti 1-y Si y The nanomultilayer (8) includes alternating layers with second nanolayers (10), where N is 0.12≦y≦0.25, and the sequence of one first nanolayer (8) and one second nanolayer (9) forms a layer period, the average layer period thickness of the nanomultilayer (8) is ≦7 nm, and the nanomultilayer (8) has a columnar structure with an average column width of ≦70 nm.

Description

[Technical Field]

[0001] The present invention relates to coated cutting tools comprising nano-multilayers of (Ti,Si)N and (Ti,Al)N. [Background technology]

[0002] Introduction Nano-multilayer coatings are commonly used in the field of cutting tools for metal machining, where at least two layers that differ in some respects form an alternating nano-layered coating.

[0003] Metal machining operations include, for example, turning, milling, and drilling.

[0004] To achieve long tool life, coated cutting tools, such as inserts, should have high resistance to different types of wear, such as flank wear resistance, crater wear resistance, chipping resistance and spalling resistance.

[0005] Different metal machining operations affect coated cutting tools in different ways. For example, turning is a continuous metal machining operation, while milling is more intermittent in nature. In milling, the thermal and mechanical loads change over time.

[0006] The former induces thermal stresses that can lead to so-called thermal cracks in the coating, referred to herein as "comb cracks," while the latter can cause edge fatigue that leads to chipping, i.e., small fragments of the cutting edge loosened from the rest of the substrate. Therefore, cracking and chipping are common wear types for coated cutting tools in milling. A high level of toughness in the coating, especially at the cutting edge, can reduce such chipping. Therefore, increasing comb crack resistance and edge line toughness is crucial for extending tool life.

[0007] To achieve cutting tools with superior properties over those currently available on the market, there is a continuing need for coated cutting tools in which the coating has superior properties in terms of flank wear resistance, crater wear resistance, edge line toughness, comb crack resistance, spalling resistance, etc. If one or more of the above properties are improved, longer tool life will be achieved.

[0008] US Patent Application Publication No. 2012 / 0114436 discloses a very general (Ti,Al)N / (Ti,Si)N nano-multilayer coating. However, it would be desirable to find a (Ti,Al)N / (Ti,Si)N nano-multilayer coating that has particularly high performance in metal machining operations. Summary of the Invention

[0009] It is an object of the present invention to provide a coated cutting tool that exhibits at least high resistance to comb cracking, high edge line toughness and high flank wear resistance.

[0010] definition The term "average layer period thickness" refers to the average thickness of a combination AB in a nanomultilayer coating of a first nanolayer A and a second nanolayer B in a nanomultilayer ABABA... If the deposition process is known, the calculation can be performed by dividing the total nanomultilayer thickness by the number of AB depositions (corresponding to the number of rotations when spinning the substrate).

[0011] Alternatively, the calculation is performed using TEM analysis of a cross section of the nanomultilayer, by counting the number of consecutive AB nanolayer combinations over a length of at least 200 nm and calculating the average value.

[0012] The term "average column width" in a nanomultilayer refers to the average value of the crystallite columns, or "particles," in the nanomultilayer. Consider a length of at least 500 nm perpendicular to the layer growth direction, and measure the column width across this length at at least four different locations in the nanomultilayer at a distance of 500 nm from the bottom contact surface of the nanomultilayer.

[0013] If the nanomultilayer has a total thickness of only 0.5 μm, the measurement location is placed directly beneath the outer surface of the nanomultilayer. Suitable methods of analysis include transmission electron microscopy (TEM).

[0014] The term "FWHM" means "full width at half maximum," which is the width in degrees (2 theta) of an X-ray diffraction peak at half its peak intensity (for a given (hkl) diffraction peak).

[0015] invention Provided herein are nano-multilayer coatings of alternating (Ti,Si)N and (Ti,Al)N layers that have surprisingly high comb crack resistance, excellent edge line toughness, and at the same time high resistance to both crater and flank wear.

[0016] The present invention relates to a coated cutting tool comprising a substrate and a coating, the coating comprising Ti 1-x Al x a first nanolayer of N, where x is 0.35≦x≦0.70; and a second nanolayer of Ti. 1-y Si y N, 0.12≦y≦0.25, wherein the sequence of one first nanolayer and one second nanolayer forms a layer period, the average layer period thickness of the nanomultilayer is ≦7 nm, and the nanomultilayer has a columnar structure with an average column width of ≦70 nm.

[0017] First nano-layer Ti 1-x Al x For N, suitably 0.45≦x≦0.70, preferably 0.55≦x≦0.65.

[0018] Second nano-layer Ti 1-y Si y For N, suitably 0.14≦y≦0.23, preferably 0.17≦y≦0.21.

[0019] The average layer period thickness of the nano-multilayer is suitably 2 to 7 nm, preferably 3 to 6 nm.

[0020] The average column width in the nano-multilayer is suitably ≦60 nm, preferably ≦55 nm. In a preferred embodiment, the average column width in the nano-multilayer is 5-60 nm, preferably 10-55 nm, more preferably 25-55 nm, most preferably 30-45 nm.

[0021] In one embodiment, the nanomultilayer has an XRD diffraction FWHM value of the cubic (200) peak of 0.6 to 1.3 degrees 2-theta, preferably 0.8 to 1.2 degrees 2-theta, and most preferably 0.9 to 1.1 degrees 2-theta.

[0022] The (200) peak in the XRD used to determine the FWHM value is the Cu-K peak that has been removed. α2 is.

[0023] The thickness of the nanomultilayer is suitably about 0.5 to about 15 μm, preferably about 1 to about 10 μm, more preferably about 1 to about 7 μm, and most preferably about 1.5 to about 4 μm.

[0024] The nano-multilayer is preferably a cathodic arc evaporation deposited layer.

[0025] In one embodiment, the coating comprises an innermost layer of TiN, (Ti,Al)N, or (Cr,Al)N beneath the nano-multilayer closest to the substrate. Preferably, the innermost layer is (Ti,Al)N. When (Ti,Al)N is used, the (Ti,Al)N is preferably TiN. 1-z Al z N, 0.35≦z≦0.70, preferably 0.45≦z≦0.70. In a preferred embodiment, the Ti-Al relationship in (Ti,Al)N is the same as the Ti-Al relationship in the first nanolayer of the nanomultilayer. The thickness of this innermost layer can be about 0.1 to about 2 μm, preferably about 0.5 to about 1.5 μm.

[0026] In a preferred embodiment, the coating is Ti 1-x Al xa first nanolayer of N, 0.55≦x≦0.65; and a second nanolayer of Ti. 1-y Si y The nanomultilayers comprise alternating layers of (Ti,Al)N with a second nanomultilayer, where y is 0.17≦y≦0.21, the average layer period thickness of the nanomultilayers is 3-6 nm, the average column width of the nanomultilayers is 25-55 nm, the thickness of the nanomultilayers is about 1 to about 7 μm, and an innermost layer of (Ti,Al)N beneath the nanomultilayer closest to the substrate has a thickness of about 0.5 to about 1.5 μm.

[0027] The substrate of the coated cutting tool can be selected from the group consisting of cemented carbide, cermet, ceramic, cubic boron nitride, and high speed steel. In one embodiment, the substrate is a cemented carbide containing 5-18 wt. % Co and 0-10 wt. % carbides, nitrides, or carbonitrides of Groups 4 and 5 of the Periodic Table of the Elements.

[0028] Further components such as Cr are possible in the cemented carbide substrate.

[0029] The coated cutting tool is preferably a cutting tool insert for metal machining, a drill or a solid end mill. The cutting tool insert is, for example, a turning insert or a milling insert. [Brief explanation of the drawings]

[0030] [Figure 1] 1 shows a schematic diagram of an embodiment of a cutting tool that is a milling insert. [Figure 2] 1 shows a schematic diagram of a cross section of one embodiment of a coated cutting tool of the present invention showing a substrate and a coating comprising various layers. DETAILED DESCRIPTION OF THE INVENTION

[0031] Figure 1 shows a schematic diagram of one embodiment of a cutting tool (1) having a rake face (2), a flank face (3), and a cutting edge (4). The cutting tool (1) is, in this embodiment, a milling insert. Figure 2 shows a schematic diagram of a cross section of one embodiment of a coated cutting tool of the present invention having a substrate body (5) and a coating (6). The coating comprises a first (Ti,Al)N innermost layer (7), followed by a Ti 1-x Al x N(9) nanolayer and Ti 1-y Si y N (10) and nano-multilayers (8) of alternating nano-layers. [Example]

[0032] Example 1: Different nanomultilayers of (Ti,Si)N and (Ti,Al)N were deposited onto sintered cemented carbide cutting tool insert blanks with geometries SNMA120408, CNMG120408MM, and R390-11. The cemented carbide composition was 10 wt% Co, 0.4 wt% Cr, and the remainder WC. The cemented carbide blanks were coated by cathodic arc evaporation in a vacuum chamber equipped with four arc flanges. Ti-Si targets were attached to two flanges facing each other. Ti-Al targets were attached to the remaining two flanges facing each other. The targets were 100 mm in diameter, round, and flat, and were commercially available. Target technology packages suitable for arc evaporation are available from commercial suppliers such as IHI Hauzer Techno Coating BV, Kobelco (Kobe Steel Ltd.), and Oerlikon Balzers.

[0033] The uncoated blank was mounted on a pin that received a three-time rotation shaft in the PVD chamber.

[0034] Samples 1-9: The chamber was placed under high vacuum (10 -2The chamber was pumped down to a pressure of less than 100 Pa and heated to 450-550 °C by a heater located inside the chamber. The blank was then etched in Ar plasma for 60 min.

[0035] The chamber pressure (reaction pressure) was set to 4 Pa ​​with N2 gas, and a DC bias voltage of -50 V (relative to the chamber wall) was applied to the blank assembly. The cathodes were operated in arc discharge mode with a current of 150 A (each) for 75 minutes (four flanges). A nano-multilayer coating with a thickness of approximately 3 μm was deposited on the blank.

[0036] Ti-Si target is Ti 0.80 Si 0.20 , Ti 0.85 Si 0.15 and Ti 0.90 Si 0.10 and the Ti-Al target is Ti 0.75 Al 0.25 , Ti 0.60 Al 0.40 , Ti 0.50 Al 0.50 , and Ti 0.40 Al 0.60 The deposition was carried out with the following combination. The total thickness of the deposited nanomultilayer was 3 μm. The rotation speed correlates to a certain period thickness. To investigate the effect of the layer period thickness in the nanomultilayer, a series of depositions of blanks were carried out using different table rotation speeds.

[0037] The targeting results in two nanolayer periods per rotation of the substrate table. For the equipment used, the correlation between table rotation speed and nanolayer period thickness is shown in Table 1. TIFF0007828904000001.tif49170

[0038] In most samples, an innermost layer of (Ti,Al)N approximately 1 μm thick was deposited. In all such cases, the (Ti,Al)N layer was deposited using the same Ti and Al contents in the target as in the fabrication of the (Ti,Al)N nanolayer in the nanomultilayer deposited above. The processing conditions for depositing the innermost (Ti,Al)N layer were a chamber pressure of 4 Pa ​​N2 gas (reaction pressure) and a DC bias voltage of −70 V (relative to the chamber wall) applied to the blank assembly. The cathodes were operated in arc discharge mode with a current of 150 A (each).

[0039] The prepared samples 1 to 12 are listed in Table 2. TIFF0007828904000002.tif113170

[0040] Samples 13-17: Further samples were prepared using combinations of DC bias voltage and N2 pressure other than -50V / 4Pa.

[0041] The chamber was placed under high vacuum (10 -2 The chamber was pumped down to a pressure of less than 100 Pa and heated to 450-550 °C by a heater located inside the chamber. The blank was then etched in Ar plasma for 60 min.

[0042] Approximately 1 μm thick Ti 0.40 Al 0.60 The innermost layer of N was deposited first. The processing conditions were a chamber pressure of 4 Pa ​​N2 gas (reaction pressure) and a DC bias voltage of -70 V (with respect to the chamber wall) applied to the blank assembly. The cathodes were operated in arc discharge mode with a current of 150 A (each).

[0043] Next, for the deposition of nano-multilayers of (Ti,Si)N and (Ti,Al)N, different chamber pressures (reaction pressures) of N gas between 2 Pa and 6 Pa were used for different samples, and different unipolar DC bias voltages (relative to the chamber wall) between -30 V and -100 V were applied to the blank assembly. The cathodes were operated in arc discharge mode with a current of 150 A (each). Nano-multilayers with a thickness of approximately 2 μm were deposited on the blanks, i.e., a total coating thickness of approximately 3 μm was achieved on each insert.

[0044] Ti-Si target is Ti 0.80 Si 0.20 and the Ti-Al target is Ti 0.40 Al 0.60 The deposition was carried out using a table rotation speed of 5 rpm, i.e. resulting in a layer period thickness of about 4 nm in the nanomultilayer.

[0045] The prepared samples 13 to 17 are listed in Table 3. TIFF0007828904000003.tif41170

[0046] To confirm the actual elemental composition of the nanomultilayers, several samples were analyzed for their average composition using energy dispersive X-ray spectroscopy (EDS). EDS measurements were performed on SEM cross-sections of the coatings over a distance that encompassed several nanolayers.

[0047] The results showed deviations from the theoretical composition of only 1-2 percent, which is within the accuracy of the EDS method. It can therefore be concluded that the actual elemental compositions of Ti, Al, and Si in the layers correspond substantially well to the respective target compositions used.

[0048] X-ray diffraction (XRD) analysis was performed using a 2D detector (VANTEC-500) and a 1 μS X-ray source (Cu-K) with an integrated parallel beam Montel mirror. aThe flanks of the coated inserts were measured using a Bruker D8 Discover diffractometer equipped with a 1000 kV (50.0 kV, 1.0 mA) and a 1000 kV (50.0 kV, 1.0 mA) detector. The coated cutting tool inserts were mounted in a specimen holder that ensured that the specimen flank was parallel to the reference plane of the specimen holder and at the appropriate height. The diffraction intensity from the coated cutting tool was measured around the 2θ angles where the relevant peaks occurred, including at least 35° to 50°. Background subtraction and Cu-K diffraction were performed. α2 Data analysis, including removal, was performed using PANalytical's X'Pert HighScore Plus software. The Pseudo-Voigt-Fit function was used for peak analysis. No thin film correction was applied to the obtained peak intensities. Possible peak overlap of any diffraction peaks not belonging to the PVD layer, e.g., the (200) peak with substrate reflections such as WC, was compensated for by the software (deconvolution of combined peaks) when determining peak intensities and peak widths. The full width at half maximum (FWHM) values ​​of the (200) peak of the samples were calculated. The results are shown in Table 4. TIFF0007828904000004.tif104170

[0049] Example 2: To evaluate the performance of the prepared samples, cutting tests were carried out.

[0050] Explanation of terms used: The following expressions / terms are commonly used in metal cutting, but are nevertheless explained in the table below: Vc (m / min): Cutting speed (meters / min) fz (mm / tooth): Feed rate (millimeters per tooth) (milling) fn (mm / rev) Feed per revolution (lathe processing) z: (number) Number of cutter blades a e (mm): Radial cutting depth (mm) a p (mm): Axial cutting depth (mm)

[0051] Comb crack resistance: Operation: Shoulder milling Tool holder: R245-080027-12M, Dc=80mm Workpiece material: Toolox33 (tool steel), L = 600 mm, I = 200 mm, h = 100 mm Insert type: R390-11 Cutting speed V c =320m / min Feed rate f z =0.3mm / rev Cutting depth a p =2mm Radial engagement a e =15mm With cutting fluid

[0052] The criterion for the end of tool life is a maximum chipping height VB>0.3 mm.

[0053] Edge line toughness: Workpiece material: Dievar uncured, P3.0.Z.AN, z=1 V c =200m / min f z =0.20mm a e =12mm a p =3.0 Length of cut = 12mm No cutting fluid

[0054] The cut-off criteria are chipping of at least 0.5 mm at the edge line or a measured depth of 0.2 mm in either the relief or rake phase. Tool life is presented as the number of cut entrances to achieve these criteria.

[0055] Flank wear test: Vertical lathe processing Workpiece material: Sverker21 (tool steel), hardness approximately 210HB, D=180, L=700mm, Vc =125m / min f n =0.072mm / rev a p =2mm No cutting fluid

[0056] The cut-off criterion for tool life is a flank wear VB of 0.15 mm.

[0057] Peeling resistance The evaluation was carried out by a lathe test on austenitic steel. The cutting depth a p The inserts were evaluated by SEM analysis.

[0058] Work: Facing (lathe processing) Workpiece material: Austenitic stainless steel bar Sanmac 316L, L = 200 mm, D = 100 mm, approx. 215HB Insert type: CNMG 120408-MM Cooling: Yes Cutting depth a p =4~0, 0~4mm Cutting speed V c =140m / min Feed rate f z =0.36mm / rev

[0059] Layer Cycle Thickness: TIFF0007828904000005.tif33170

[0060] Table 5 shows that the thickest layer period of 20 nm showed the worst performance in terms of peel resistance.

[0061] Furthermore, the test results (Sample 1, Sample 2, Sample 3) show that, among the tested layer periods of 4 nm (5 rpm), 8 nm (2.4 rpm), and 20 nm (1 rpm), the best comb crack resistance result was 30 cuts until the cutoff criterion for the 4 nm layer period was observed. For a layer period of 8 nm, the comb crack resistance result was 23 cuts, and for a layer period of 20 nm, the comb crack resistance result was 21 cuts. Results below 25 minutes are considered insufficient. Therefore, the smaller the layer period, the better the results. Therefore, the preferred range for the average layer period of the nano-multilayer is considered to be 2-7 nm, preferably 3-6 nm.

[0062] Effects of the innermost layer: Ti 0.40 Al 0.60 N / Ti 0.80 Al 0.20 Samples with deposited nanomultilayers of N (target composition) were tested with and without an additional innermost layer directly on the substrate. TIFF0007828904000006.tif28170

[0063] The comb crack resistance results are improved by the presence of an additional innermost (Ti,Al)N layer.

[0064] Although ELT tests were not performed on samples without the additional innermost layer, Table 7 at least shows the effect of the thickness of the additional innermost layer on ELT. The samples in Table 7 are outside the scope of the present invention due to the layer period thickness of 8 nm. However, the effect on ELT with respect to the change in the layer thickness of the innermost layer is considered to follow the same trend for layer periods of less than 8 nm, i.e., within the present invention. TIFF0007828904000007.tif33170

[0065] The ELT is believed to be improved by the presence of an additional innermost (Ti,Al)N layer. Comparing innermost layers of thickness 0.2, 0.4 and 0.8 μm, the 0.8 μm thickness produced better performance than the thinner ones.

[0066] Ti / Al relationship in (Ti,Al)N nanolayers: TIFF0007828904000008.tif38170

[0067] From the test results, the best result for comb crack resistance was obtained for sample 4 (Ti 0.40 Al 0.60 It can be seen that it takes 39 cuts to reach the cutoff criterion for sample 7 (Ti 0.75 Al 0.25 ), the comb crack resistance result was only 19 cuts. A result of less than 25 cuts is considered insufficient. Therefore, sample 4 (Ti 0.40 Al 0.60 ), sample 5 (Ti 0.50 Al 0.50 ) and sample 6 (Ti 0.60 Al 0.40 All of the (Ti,Al)N sublayers in the nano-multilayers showed good performance in the comb crack resistance test. Therefore, the required range of Al in the (Ti,Al)N sublayer composition in the nano-multilayers is considered to be the range of Ti to Al from the viewpoint of good comb crack resistance. 1-x Al x N, 0.35≦x≦0.70.

[0068] However, considering ELT performance, Ti 0.60 Al 0.40 N / Ti 0.40 Si 0.20 The best performance in both comb crack resistance and edge line toughness is seen for Ti. 0.40 Al 0.60 N / Ti 0.40 Si 0.20 The sample was sample 4.

[0069] Therefore, a suitable range of Al content is 0.45≦x≦0.70, and a preferred range is 0.55≦x≦0.65.

[0070] Ti / Si relationship in (Ti,Si)N nanolayers: TIFF0007828904000009.tif31170

[0071] Regarding comb crack resistance, specimen 8 (Ti 0.40 Al 0.60 N / Ti 0.85 Si 0.15 N) shows very good results in comb crack resistance, with 27 cuts to the cut-off criterion. It also has good flank wear resistance (17.7 min). However, the results are unsatisfactory in terms of edge line toughness. 0.40 Al 0.60 N / Ti 0.90 Si 0.10 N) also shows very good results in comb crack resistance, 25 cuts to the cut-off criterion, but completely inadequate flank wear resistance (13.5 min) and poor edge line toughness (15 cuts).

[0072] The best performance in terms of comb crack resistance, edge line toughness and flank wear is achieved with Ti. 0.40 Al 0.60 N / Ti 0.80 Si 0.20 The second best was sample 4 of N. 0.40 Al 0.60 N / Ti 0.85 Si 0.15 N) sample 8, while (Ti 0.40 Al 0.60 N / Ti 0.90 Si 0.10 N) sample 9 is deemed insufficient.

[0073] Therefore, the required operating range of Si content in the (Ti,Si)N sublayers in the nanomultilayer is 1-y Si y N, it is believed that 0.12≦y≦0.25. Suitably 0.14≦y≦0.23, preferably 0.17≦y≦0.21.

[0074] Too high a Si content in the (Ti,Si)N sublayer is expected to decrease the toughness (ELT) of the nanomultilayer.

[0075] Particle size, FWHM: Exceptional results in edge line toughness (ELT) tests (number of cuts) were observed for samples in which nanomultilayers were deposited using certain levels of DC bias voltage and / or N2 pressure. The test results for Sample 4 (-50 V, 4 Pa), Sample 13 (-30 V, 4 Pa), Sample 14 (-70 V, 4 Pa), Sample 15 (-100 V, 4 Pa), Sample 16 (-50 V, 2 Pa), and Sample 17 (-50 V, 6 Pa) show that coatings deposited at an N2 pressure of 4 Pa ​​produce very good ELT results when the DC bias voltage level used is at least -70 V, and even better -100 V (Samples 14 and 15). For coatings deposited at an N2 pressure of 2 Pa, excellent ELT results were already achieved using a DC bias voltage of -50 V (Sample 16). The starting layer was approximately 1 μm. The nanomultilayer thickness was approximately 2 μm. TIFF0007828904000010.tif54170

[0076] For the samples with excellent ELT results (Sample 14 (-70 V, 4 Pa), Sample 15 (-100 V, 4 Pa), and Sample 16 (-50 V, 2 Pa)), the comb crack test results were also excellent (29, 31, and 34 cuts, respectively).

[0077] Therefore, it can be concluded that to achieve a coating with the best edge line toughness, the bias voltage-pressure relationship in the deposition process should be either a DC bias voltage of -65 to -125 V with an N2 pressure of 3 to 6 Pa, or a DC bias voltage of -30 to -75 V with an N2 pressure of 1 to 3 Pa.

[0078] From Sample 4 (-50 V, 4 Pa), Sample 13 (-70 V, 4 Pa), and Sample 15 (-100 V, 4 Pa), it can be seen that the higher DC bias voltages used result in lower grain sizes (average column widths) in the nanomultilayers (-50 V yields 54 nm, -70 V yields 50 nm, and -100 V yields 37 nm). The lower grain sizes are also reflected in higher FWHM values. Therefore, the range of the average column width in the nanomultilayers is considered to be suitably ≦70 nm, preferably ≦55 nm. The lower limit is considered to be suitably ≧5 nm, preferably ≧10 nm, more preferably ≧25 nm. The most preferred range is considered to be 30-45 nm.

Claims

1. A coated cutting tool (1) comprising a substrate (5) and a coating (6), wherein the coating (6) is Ti １－ｘ Al ｘ N, a first nanolayer (9) where 0.35≦x≦0.70, and Ti １－ｙ Si ｙ 1. A coated cutting tool (1) comprising a nano-multilayer (8) of alternating layers with a second nano-layer (10) having a first nano-layer (9) and a second nano-layer (10) with N and y being 0.12≦y≦0.25, wherein a sequence of one first nano-layer (9) and one second nano-layer (10) forms a layer period, the nano-multilayer (8) having an average layer period thickness of ≦7 nm, the nano-multilayer (8) having a columnar structure with an average column width of ≦70 nm, the nano-multilayer (8) having a thickness of 0.5 to 15 μm, and an FWHM value of the cubic (200) peak in X-ray diffraction being 0.7 to 1.2 degrees (2-theta).

2. For the first nanolayer (9), Ti １－ｘ Al ｘ 2. The coated cutting tool (1) according to claim 1, wherein N, 0.45≦x≦0.

70.

3. For the second nanolayer (10), Ti １－ｙ Si ｙ 3. The coated cutting tool (1) according to claim 1, wherein N, 0.14≦y≦0.

23.

4. The coated cutting tool (1) according to any one of claims 1 to 3, wherein the nano-multilayer (8) has an average layer period thickness of 2 to 7 nm.

5. 5. The coated cutting tool (1) according to any one of claims 1 to 4, wherein the nano-multilayer (8) has an average column width of ≦55 nm.

6. Coated cutting tool (1) according to any one of claims 1 to 5, wherein the nano-multilayer (8) has an average column width of 30 to 45 nm.

7. The coated cutting tool (1) according to any one of claims 1 to 6, wherein the FWHM value of the cubic (200) peak in X-ray diffraction is 0.8 to 1.2 degrees (2-theta).

8. The coated cutting tool (1) according to any one of claims 1 to 6, wherein the FWHM value of the cubic (200) peak in X-ray diffraction is 0.9 to 1.1 degrees (2-theta).

9. Coated cutting tool (1) according to any one of claims 1 to 8, wherein the nano-multilayer (8) has a thickness of 1 to 7 μm.

10. 10. The coated cutting tool (1) according to any one of claims 1 to 9, wherein the coating (6) comprises an innermost layer (7) of TiN, (Ti,Al)N or (Cr,Al)N having a thickness of 0.1 to 2 μm beneath the nano-multilayer (8) closest to the substrate.

11. The innermost layer (7) is Ti １－ｚ Al ｚ 11. The coated cutting tool (1) according to claim 10, wherein N, 0.35≦z≦0.

70.

12. Coated cutting tool (1) according to any one of claims 1 to 11, wherein the nano-multilayer (8) is a cathodic arc evaporation deposited layer.

13. 13. The coated cutting tool (1) according to any one of claims 1 to 12, wherein the substrate (5) of the coated cutting tool (1) is selected from the group consisting of cemented carbide, cermet, ceramic, cubic boron nitride and high speed steel.

14. The coated cutting tool (1) according to any one of claims 1 to 13, wherein the coated cutting tool (1) is a cutting tool insert for metal machining, a drill or a solid end mill.

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