A coated cutting tool

Abstract

The present invention relates to a coated cutting tool (1) for metal machining comprising a cemented carbide substrate body (5) and a coating (6) comprising a layer of a metal nitride, there is an uppermost part of the cemented carbide substrate body (5) wherein there are uppermost WC grains adjacent to the coating (6), there is an intermediate zone between an uppermost part of said WC grains and the coating (6) comprising a peak of Me3 intensity in an EDX line scan made from within the coating (6) into a WC grain perpendicular to the surface plane of the WC grain, Me3 is one of Ti, Cr, Zr, Mo, Nb and V, the average content of Me3 within + / - 10 nm from the Me3 max peak position is from 2 to 30 at%, the Me3 within + / - 1.0 nm from the Me3 max peak position in the EDX line scan is present as a metal nitride or carbonitride, the average content of any noble gas element or combination of noble gas elements, within + / - 1.0 nm from the Me3 max peak position in the EDX line scan, is ≤0.6 at%.

Description

[0001] A coated cutting tool

[0002] The present invention relates to a coated cutting tool for metal machining wherein there is a cemented carbide substrate with a coating comprising a metal nitride layer.

[0003] Introduction

[0004] In metal machining operations cutting tools, such as inserts, are used. A cutting tool generally has at least one rake face and at least one flank face. A cutting edge is present where a rake face and flank face meet. Metal machining operations include, for example, turning, milling, and drilling. As examples of cutting tools are cutting inserts, endmills and drills.

[0005] In order to provide a long tool life, a cutting tool should have high resistance against different types of wear. In order to increase wear resistance of a cutting tool various types of wear resistant coatings are known in the art. Metal nitride layers are commonly used in such wear resistant coatings. Especially metal nitrides deposited in a physical vapour deposition process. Examples of metal nitrides are nitrides of one or more of titanium, chromium and zirconium, sometimes in combination with aluminium and / or silicon. Monolayers of metal nitrides or multilayers of alternating sublayers of different metal nitrides can be used.

[0006] Cemented carbide is commonly used as a substrate material in a coated cutting tool as discussed above. Cemented carbide comprises hard constituents of tungsten carbide grains in a binder phase. The binder phase is usually made of cobalt, although other elements like iron and nickel may be used in binder compositions. There may also be further hard constituent grains of metal carbides or carbonitrides present in the cemented carbide.

[0007] The influence of the properties of the interface between a cemented carbide substrate and a metal nitride layer to metal cutting performance is complex. One aspect can be referred to as the adhesion between a metal nitride layer and a cemented carbide substrate. In order to provide high performance of the cutting tool the adhesion must be sufficiently high avoiding that the coating flakes off during use of the cutting tool. The adhesion of a metal nitride to a substrate may be influenced by, for example, the elemental composition of the metal nitride, the residual stress level in the metal nitride layer as well as at the surface of the cemented carbide, the roughness of the substrate surface and the general properties of the interface between the cemented carbide and the metal nitride layer.

[0008] Cutting tools for metal machining are subjected to different types of wear during use. Different metal machining operations affect a coated cutting tool in different ways. Turning, for example, is a continuous metal machining operation while milling is more intermittent in nature.

[0009] One type of wear which is of high importance in turning operations is flank wear which takes place on a flank face of the cutting edge, mainly from an abrasive wear mechanism. The flank face is subjected to workpiece movement and too much flank wear will lead to poor surface quality of the workpiece, inaccuracy in the cutting process and increased friction in the cutting process.

[0010] In milling the thermal and mechanical load vary over time. Thermal load induces thermal tensions which may lead to so-called thermal cracks, herein referred to as "comb cracks", in a coating, while the later may cause fatigue in the cutting edge leading to chipping, i.e., small fragments of the cutting edge loosening from the rest of the substrate. Thus, common wear types of a coated cutting tool in milling are cracking and chipping. A high comb crack resistance is thus of importance for tool lifetime in, for example, a milling operation. A high edge line toughness is, furthermore, an important property of a cutting tool in milling operations.

[0011] Machining of ISO-S materials, such as titanium and heat resistant super alloys (HRSA), puts special demands on the cutting tool. The ISO-S materials have, for example, poor heat conductivity which generates high temperatures during machining creating wear. Also, the tendency of strong work hardening of the ISO-S materials lead to risk of built up edge on the cutting tool which effects the quality of the workpiece such as poor surface finish. Furthermore, when machining titanium problems due to the high reactivity of titanium may occur especially at the high temperatures created during machining. Typically smearing is connected to the formation of built up edge. Also when machining ISO-M materials, i.e., stainless steel, adhesive wear is an important wear mechanism, especially in milling operations. Adhesive wear, or smearing, is characterized in that during the cutting process of sticky materials, such as stainless steel, workpiece material is smeared over, and adhered to, the cutting edge creating a layer of material which may form a so called built-up edge. Flaking of the coating is a common problem in connection to adhesive wear.

[0012] The properties of an interface between a cemented carbide substrate and a coating thereon may influence not only flaking behaviour as discussed above but also other types of wear, such as flank wear.

[0013] There is a continuing demand for wear resistant coated cutting tools with improved tool life.

[0014] Object of the invention

[0015] There is an object of the present invention to provide a coated cutting tool for metal machining which has a long tool life in metal cutting operations.

[0016] The invention

[0017] It has now been provided a coated cutting tool for metal machining which, at least, shows high flank wear resistance and / or high flaking resistance in metal cutting operations in one or more of ISO-S and ISO-M workpiece materials. Preferably, the coated cutting tool also has high edge line toughness in milling operations of one or more of ISO-P, ISO-S and ISO-M workpiece materials.

[0018] The present invention relates to a coated cutting tool for metal machining comprising a rake face, a flank face and a cutting edge inbetween, the coated cutting tool further comprises a cemented carbide substrate body and a coating thereon, wherein the coating comprises a from 0.2 to 15 pm thick layer of Me1 N, wherein Me1 is one or more metals of group 4 to 6 in the periodic table of elements or one or more metals of group 4 to 6 in the periodic table of elements in combination with Al and / or Si, the cemented carbide comprises WC, in the form of WC grains, within a binder phase, there is an uppermost part of the cemented carbide substrate body wherein there are uppermost WC grains adjacent to the coating, there is an intermediate zone between an uppermost part of said WC grains and the coating comprising a peak of Me3 intensity in an EDX line scan made from within the coating into a WC grain perpendicular to the surface plane of the WC grain, Me3 is one of Ti, Cr, Zr, Mo, Nb and V, the average content of Me3 within + / - 1 .0 nm from the Me3 max peak position is from 2 to 30 at%, the Me3 located within + / - 1 .0 nm from the Me3 max peak position in the EDX line scan is present as a metal nitride or carbonitride, the average content of any noble gas element or combination of noble gas elements, within + / - 1 .0 nm from the Me3 max peak position in the EDX line scan, is <0.6 at%.

[0019] By Me3 max peak position in the EDX line scan is herein meant the position in the EDX line scan where the maximum value of the peak of Me3 intensity is located.

[0020] In one embodiment, the peak of Me3 intensity in the EDX line scan has a full width at half maximum (FWHM) of from 1 .0 to 6.0 nm, or from 1 .5 to 5.0 nm, as determined from the average baseline intensity of Me3 in the coating between 6 and 11 nm from the peak position of Me3.

[0021] In one embodiment, the peak of Me3 intensity in the EDX line scan has a full width at half maximum (FWHM) of from 2.0 to 4.0 nm, as determined from the average baseline intensity of Me3 in the coating between 6 and 11 nm from the peak position of Me3.

[0022] In one embodiment, the peak of Me3 intensity in the EDX line scan has a full width at half maximum (FWHM) of from 3.0 to 6.0 nm, as determined from the average baseline intensity of Me3 in the coating between 6 and 11 nm from the Me3 max peak position.

[0023] As a noble gas element is herein meant an element belonging to the group of Ne, Ar, Kr and Xe.

[0024] The average content of any noble gas element or combination of noble gas elements, within + / - 1 .0 nm from the Me3 max peak position in the EDX line scan, is suitably <0.5 at%, preferably <0.4 at%, more preferably <0.3 at%, even more preferably <0.2 at%, most preferably <0.1 at%, or not any detectable amount.

[0025] In one embodiment, the average content of any noble gas element or combination of noble gas elements, within + / - 1 .0 nm from the Me3 max peak position in the EDX line scan, is suitably >0.1 at% but <0.6 at%, of any noble gas element or combination of noble gas elements.

[0026] It has surprisingly been found that a long tool life is provided by providing a coated cutting tool of the present disclosure. The coated cutting tool herein disclosed shows at least excellent resistance to secondary notch wear, which is a type of local flank wear, in combination with excellent flaking resistance in finishing turning operation of ISO S and drilling operations of ISO-S and ISO-M workpiece materials. Also, high edge line toughness in milling operations of ISO P, ISO-S and ISO-M workpiece materials.

[0027] In one embodiment, Me3 is one of Cr, Zr, Mo, Nb and V.

[0028] In one embodiment, Me3 is one of Zr, Mo, Nb and V.

[0029] In one embodiment, Me3 is one of Mo and V.

[0030] The average content of Me3 within + / - 1 .0 nm from the Me3 max peak position is suitably from 3 to 25 at%, or from 4 to 20 at%.

[0031] In one embodiment, the average content of Me3 within + / - 1 .0 nm from the Me3 max peak position is from 5 to 15 at%.

[0032] In one embodiment, the average content of Me3 within + / - 1 .0 nm from the Me3 max peak position is from 3 to 10 at%.

[0033] In one embodiment, the average content of Me3 within + / - 1 .0 nm from the Me3 max peak position is from 10 to 25 at%.

[0034] The Me1 N layer has suitably a thickness of from 0.5 to 10 pm, preferably from 1 to 5 pm.

[0035] In the Me1 N layer, Me1 is suitably one or more of Ti, Cr and Zr, or one or more of Ti, Cr and Zr in combination with Al and / or Si.

[0036] The Me1 N layer is suitably any one of TiAIN, TiAISiN, TiAICrN, TiAICrSiN, TiAIZrN, TiAICrAIN, TiAISiN, CrAIN, or CrAISiN.

[0037] Further layers of, e.g., metal nitrides or oxides may be present on top of the Me1 N layer.

[0038] In one embodiment the Me1 N layer is a monolithic layer. In one embodiment the Me1 N layer is a multilayer of alternating sublayers (MeaiN, Mea2N, ...MeanN), n is a number from 2 to 5, or from 2 to 4, or from 2 to 3, of different elemental composition. Meai, Mea2, ...Meanare each one or more of Me is one or more metals of group 4 to 6 in the periodic table of elements or one or more metals of group 4 to 6 in the periodic table of elements in combination with Al and / or Si. The average sublayer thicknesses of the alternating sub-layers (MeaiN, Mea2N, ...MeanN) are suitably each from 1 to 100 nm, or from 2 to 50 nm, or from 3 to 20 nm.

[0039] In one embodiment, Meai, Mea2, ...Meanare each one or more of Ti, Cr and Zr, or one or more of Ti, Cr and Zr in combination with Al and / or Si.

[0040] As embodiments of Me1 N being a multilayer can be mentioned a multilayer of TiAIN and TiSiN sub-layers, i.e. , an overall TiAISiN layer, a multilayer of TiAIN, TiSiN and CrAIN sub-layers, i.e., an overall TiAICrSiN layer, a multilayer of TiAIN and TiAISiN sub-layers, i.e., an overall TiAISiN layer, or a multilayer of TiAIN and AICrN sub-layers, i.e., an overall TiAICrN layer.

[0041] In one embodiment, over a distance starting at 6 nm and ending at 11 nm from the Me3 max peak position in the EDX line scan, in the direction into the coating, the average content of Me3 is at most 2 at%, suitably at most 1 at%, preferably at most 0.5 at%. Thus, the Me3 content in the coating closest to the substrate at a distance of between 6 and 11 nm from the Me3 max peak position in the EDX line scan should be at most 2 at%, suitably at most 1 at%, preferably at most 0.5 at%. Within this embodiment, over a distance starting at 6 nm and ending at 11 nm from the Me3 max peak position in the EDX line scan, in the direction into the coating (6), the coating (6) suitably comprises (Me2xSiyAlz)N, wherein Me2 is one or more metals of group 4 to 6 in the periodic table of elements, 0.25<x<1 , 0<y<0.3, 0<z<0.75, x+y+z=1. Suitably 0.35<x<1 , 0<y<0.2, 0<z<0.70.

[0042] In one embodiment, Me2 equals Me1.

[0043] In one embodiment, Me2 is different from Me3.

[0044] In one embodiment, Me3 is Ti. In this case Me2 is suitably one or more of Cr and Zr.

[0045] In one embodiment, Me3 is Cr. In this case Me2 is suitably one or more of Ti and Zr. In one embodiment, Me3 is Zr. In this case Me2 is suitably one or more of Ti and Cr.

[0046] In one embodiment, Me3 is Nb. In this case Me2 is suitably one or more of Ti, Cr and Zr.

[0047] In one embodiment, Me3 is Mo. In this case Me2 is suitably one or more of Ti, Cr and Zr.

[0048] In one embodiment, Me3 is V. In this case Me2 is suitably one or more of Ti, Cr and Zr.

[0049] The Me3 located within + / - 1 .0 nm from the Me3 max peak position in the EDX line scan is present as a metal nitride or carbonitride. Thus, Me3 is not present as a metallic phase within + / - 1 .0 nm from the Me3 max peak position in the EDX line scan.

[0050] In one embodiment, within + / - 1 .0 nm from the Me3 max peak position in the EDX line scan, there is N, C and W present.

[0051] In one embodiment, the average content of N within + / - 1 .0 nm from the Me3 max peak position in the EDX line scan, is from 15 to 40 at%.

[0052] In one embodiment, the average content of C within + / - 1 .0 nm from the Me3 max peak position in the EDX line scan, is from 5 to 25 at%.

[0053] In one embodiment, the average content of W within + / - 1 .0 nm from the Me3 max peak position in the EDX line scan, is from 15 to 45 at%.

[0054] In one embodiment, the uppermost WC interface occupies 75 to 100% of a total interface between the cemented carbide substrate body and the coating, as measured in a cross sectional cut of the cutting tool perpendicular to the cemented carbide substrate body surface plane, suitably 80 to 98%, or 85 to 98%, or 90 to 96%, of a total interface between the cemented carbide substrate body and the coating, as measured in a cross sectional cut of the cutting tool perpendicular to the cemented carbide substrate body surface plane.

[0055] The Me1 N layer in the present invention, as well as (Me2xSiyAlz)N, is suitably of cubic NaCI structure, or of a mixture of hexagonal crystal structure and cubic NaCI crystal structure.

[0056] Within + / - 1 .0 nm from the Me3 max peak position in the EDX line scan the intermediate zone is suitably of cubic NaCI structure. The crystal structures, cubic and hexagonal, are suitably being detected by TEM analysis.

[0057] In one embodiment, there are lattice stripes as seen in a STEM image, when going from within an uppermost WC grain adjacent to the coating into the coating. The presence of lattice stripes indicates crystallinity in all of the WC, the intermediate zone between the WC and the coating, and the innermost part of the coating.

[0058] The substrate of the coated cutting tool is a cemented carbide comprising WC in a binder phase.

[0059] Suitably, the cemented carbide comprises from 70 to 95 wt% WC, or from 80 to 94 wt% WC, or from 85 to 93 wt% WC.

[0060] The binder phase can be any suitable metal binder used in cemented carbide substrates. The metal binder is suitably Co, Ni or Fe, or combinations thereof. In one embodiment the metal binder is Co.

[0061] The metal binder content in the cemented carbide is suitably from 5 to 18 wt%, or from 6 to 14 wt%. The cemented carbide may comprise additional constituents, besides WC and metal binder, commonly used in the art, such as cubic carbides or carbonitrides of one or more elements of group 4 and 5 in the periodic table of elements, such as carbides or carbonitrides of one or more of Ti, Ta and Nb, also called gamma phase, the amount being, for example, >0 wt% but <25 wt%, or from 0.1 to 10 wt%. Further components like Cr are possible in the cemented carbide substrate.

[0062] The WC grain size is suitably 0.1 to 2 pm, or from 0.2 to 1.5 pm, or from 0.3 to 1 pm.

[0063] The grain size of the WC, d, is herein determined from the value of magnetic coercivity. The relationship between coercivity and grain size of WC is described, e.g., in Roebuck et al., Measurement Good Practice No. 20, National Physical Laboratory, ISSN 1368-6550, November 1999, Revised February 2009, Section 3.4.3, pages 19-20. For the purposes of this application the grain size of the WC, d, is determined according to formula (8) on page 20 in the above-mentioned literature:

[0064] K=(ci+diWco)+ (C2+d2Wco) / d. Re-arranging one gets: d = (C2+d2Wco) / (K-(ci+diWco)), wherein d= WC grain size of the cemented carbide body, K= coercivity of the cemented carbide body in kA / m, herein measured according to standard DIN IEC 60404- 7 , Wco = wt% Co in the cemented carbide body, ci = 1 .44, C2 = 12.47, di = 0.04, and d2 = -0.37.

[0065] The coated cutting tool can be a cutting tool insert, a drill, or a solid endmill, for metal machining. In the case of the cutting tool being an insert it is suitably a milling, drilling or turning insert.

[0066] The Me1 N layer and (Me2xSiyAlz)N are deposited in a PVD process. Any type of PVD process may be used such as reactive sputtering, HIPIMS, ion plating or cathodic arc evaporation. Preferably, a cathodic arc evaporation process is used.

[0067] Thus, in one embodiment the layer of The Me1 N layer and (Me2xSiyAlz)N are both cathodic arc deposited.

[0068] Methods:

[0069] Preparation of TEM lamellas for analysis:

[0070] Scanning electron and focused ion beam microscopy (SEM / FIB) (Helios NanoLab 650, FEI) was used for fabrication of site specific thin lamellas for transmission electron microscopy (TEM). No noble gas ion bombardment must be used during thinning of the TEM sample since the noble gas content is one feature defining the present invention and using noble gas bombardment in TEM sample thinning might influence later measurements. A standard lift out technique was used with one or two final low kV cleaning steps, 5kV and in some cases also 2kV. The TEM lamellae thickness was aimed at to be thinner than 100 nm. The TEM lamellae were obtained by cutting a section including the uppermost part of the cemented carbide substrate body and the lowermost part of the coating in a direction perpendicular to the surface of the substrate body. The TEM lamellae were cut at a position on a flank face at a position of about 200 pm distance from the surface plane of a rake face. Also, there was a distance of 1 mm away from any other flank face. The TEM lamellae contained the full coating thickness of the samples and at least 2 pm of the uppermost part of the substrate.

[0071] TEM analysis:

[0072] TEM data, including scanning TEM (STEM) images, and EDX spectrum images, were collected on either a Titan G2 or a Themis aberration-corrected (image and probe) TEM operated at 300 kV. EDX data were collected on a SuperX detector. STEM images were collected at a camera length of 29.5 mm on Gatan ADF, Gatan HAADF (for Titan G2 only) and FEI HAADF detectors. The beam convergence angle was 21 .4 mrad for Titan G2 and 21 .0 mrad for Themis. The beam current for image acquisition was ~100 pA and for spectrum imaging 350-600 pA.

[0073] STEM image and spectrum image analysis were done in GMS version 3.53 for Titan G2 and GMS version 3.60.4437.0. for Themis. EDX quantification was done in Broker Esprit version 1 .9.4 on data exacted from spectrum images.

[0074] Provision of EDX line scans and determination of content of noble gas, Me3, N, C, and W:

[0075] The noble gas element content, as well as the contents of the elements Me3, N, C and W, is herein determined by TEM-EDX.

[0076] "Net intensity" maps of the different elements of interest are created from the EDX spectrum images using the GMS software. The background correction mode is set to ‘Kramers’. EDX line scans, i.e., line profiles of the different elements, are then extracted from the net intensity maps by applying a line profile window. The integration dimension of the line profile window is set to be 15-20 nm and is placed parallel to the interface between the WC grain and the coating. The profile dimension of the line profile window is set to be 20-25 nm and runs cross the interface.

[0077] The noble gas content, e.g., Ar, as well as the Me3, N, C, and W contents, is determined by analysing integrated EDX signals from a rectangular area on a spectrum image within the uppermost zone of a WC grain. The height (along the direction perpendicular to the interface between the WC grain and the coating) of the rectangular area was selected to be about 2.0 nm and centered around the position of the Me3 max peak in the EDX line scan. Quantification is done by using the Cliff-Lorimer method in Esprit. Lines deconvolution is set to use "series fit" and the background model is set to "physical (TEM)".

[0078] The length of the rectangular area was selected to be at least 10 nm, for example 20-30 nm, extending along an interface between the WC grain and the coating.

[0079] In the measurements herein made, the pixel time was 5-10 ms and the number of passes was between 30-60, or about 100 in some cases, for the longexposure maps with drift correction.

[0080] Method for determining the occupancy of the uppermost WC interface and the uppermost binder phase interphase to the coating:

[0081] An insert was grinded and then polished in steps until a final step using a 1 pm diamond-oil slurry on a piece of paper put on a hard disc. This method gives very low interface rounding and substantially no preferential etching of binder metal, such as Co. The measurement at the substrate-coating interface was made on a cross section of an insert. The combination of grinding and polishing removes about 1 .4 mm of the insert full width.

[0082] The measurement was made at 10000X magnification giving a full image width of about 11 ,4 pm (high res. micrographs 3072 x 2304 pix to permit further zoom if needed). The regions with binder metal-contact with the upper coating were measured and summed together. The % coverage of WC (total image width) relative binder phase (summed length) was then calculated.

[0083] The measurements were made about 200 pm from the edge line on the flank side of the insert. An average value from measurements on images of at least three different positions gave the stated values. In the measurements a length of at least 10 pm per image should be used. Description of drawings

[0084] Figure 1 shows a schematic view of one embodiment of a cutting tool (1 ) having a rake face 2 and flank faces 3 and a cutting edge 4. The cutting tool 1 is in this embodiment a milling insert.

[0085] Figure 2 shows a schematic view of one embodiment of a cutting tool 1 having a rake face 2 and flank face 3 and a cutting edge 4. The cutting tool 1 is in this embodiment a turning insert.

[0086] Figure 3 shows a schematic view of a cross section of an embodiment of the coated cutting tool of the present invention having a substrate 5 of cemented carbide and a coating 6.

[0087] Figure 4a shows an EDX line scan of sample 1 (invention). The scan starts within the coating and goes into a WC grain. A peak of Zr content is seen.

[0088] Figure 4b shows a close-up of the EDX line scan of Figure 4a.

[0089] Figure 5a shows an EDX line scan of sample 2 (invention). The scan starts within the coating and goes into a WC grain. A peak of V content is seen.

[0090] Figure 5b shows a close-up of the EDX line scan of Figure 5a.

[0091] Figure 6a shows an EDX line scan of sample 3 (invention). The scan starts within the coating and goes into a WC grain. A peak of Cr content is seen.

[0092] Figure 6b shows a close-up of the EDX line scan of Figure 6a.

[0093] Figure 7a shows an EDX line scan of sample 4 (invention). The scan starts within the coating and goes into a WC grain. A peak of Nb content is seen.

[0094] Figure 7b shows a close-up of the EDX line scan of Figure 7a.

[0095] Figure 8a shows an EDX line scan of sample 5 (invention). The scan starts within the coating and goes into a WC grain. A peak of Mo content is seen.

[0096] Figure 8b shows a close-up of the EDX line scan of Figure 8a.

[0097] Figure 9a shows an EDX line scan of sample 6 (invention). The scan starts within the coating and goes into a WC grain. A peak of Ti content is seen.

[0098] Figure 9b shows a close-up of the EDX line scan of Figure 9a. Examples

[0099] Example 1 :

[0100] Sintered cemented carbide cutting tool insert blanks of the geometries SNMA 120408 (flat insert for analysis), CNMG120804-MM and SM (turning insert) and R390-11T308M-PM (milling insert) were provided and placed in a PVD chamber. After sintering the blanks had been subjected to a wet blasting treatment.

[0101] The composition of the cemented carbide was 7 wt% Co, 0.7 wt% Cr, 0.01 wt% Ta and 0,014 at% Ti and rest WC for the CNMG120804-SM insert. The composition of the cemented carbide was 10 wt% Co, 0.4 wt% Cr and rest WC for the SNMA120804-MM insert and R390-11T308M-PM inserts.

[0102] The WC grain size, as herein defined, was 0.4 pm for the cemented carbide containing 7 wt% Co and 0.5 pm for the cemented carbide containing 10 wt% Co.

[0103] The cemented carbide blanks were coated by cathodic arc evaporation in a PVD vacuum chamber comprising six arc flanges, each flange comprising several cathode evaporators.

[0104] Targets (sources) of Ti40AI60, alternatively Cr30AI70, were mounted in the evaporators in 3 or 4 flanges in a batch coater having 4 or 6 active flanges, respectively. Depending on which sample is to be made, a target (source) of a metal Me3 being Zr, V, Cr, Nb, Mo or Ti, was mounted in 1 flange. The targets were circular and planar with a diameter of 100 mm available on the open market. Suitable arc sources to be used within this invention are the ones called Super Fine Cathode (SFC) from Kobelco (Kobe Steel Ltd.). Such a SFC cathode was herein used in the treatments and deposition of coatings. SFC cathodes are discussed in Yamamoto et al., "Cutting Performance of Low Stress Thick TiAIN PVD Coatings during Machining of Compacted Graphite Cast Iron (CGI)", Coatings 2018, 8, 38; doi:10.3390 / coatings8010038.

[0105] The PVD chamber comprises a circular rotatable substrate table and the uncoated cutting tool insert blanks, which each has a hole like the inserts in the schematic figures 1 and 2, were mounted on pins located at the circumference of the substrate table. The table diameter was 0.82 m. The distance between the circumference of the substrate table and the targets was about 27 cm.

[0106] The mounting of the inserts was such that the flank faces of the inserts would substantially face the cathode evaporators during rotation in the PVD chamber during the sample preparation processes.

[0107] The cutting tool insert blanks underwent a three-fold rotation in the PVD chamber during deposition of the coating. The table rotation speed was 5 rpm.

[0108] The chamber was pumped down to high vacuum (less than 10’2Pa) and heated to about 350-450°C by heaters located inside the chamber.

[0109] The cemented carbide blanks were subjected to treatments as follows: First of all, all cemented carbide blanks were subjected to an Ar ion etching step. The purpose of the Ar etching is to remove any loose fragments of WC that may be present on the substrate surface and also to remove any binder phase present on the uppermost WC grains facing the surface after the earlier wet blasting. In this etching step the substrates are cleaned thourogly from such defects. In the following sample preparation a substrate bias level of - 200V and about 0,7 Pa of Ar-pressure was used, resulting in an average bias current of about 15-17 A for the used substrate table.

[0110] Ten separate runs were made. Since there were two different substrates used the samples are denoted 1a, 1 b, 2a, 2b, etc.

[0111] For samples "a" the composition of the cemented carbide was 7 wt% Co, 0.7 wt% Cr, 0.01 wt% Ta and 0,014 at% Ti and rest WC.

[0112] For samples "b" the composition of the cemented carbide was 10 wt% Co, 0.4 wt% Cr and rest WC.

[0113] In ten separate runs a first step of Ar ion etching was performed. A DC bias voltage of -200V was used, at an Ar pressure of 0.7 Pa. The etch time was 55 min. Table 1 shows the samples. Table 1.

[0114] In one of the separate runs (Sample 1 ) seen in Table 1 a Zr ion treatment step was performed. In this step an arc current of 170 A was applied to the mounted Zr target in the PVD chamber, and a DC bias voltage level of -200 V were applied to the cutting tool blanks as seen in Table 2. Further information of Ar gas pressure and treatment time are found in Table 2.

[0115] A layer of Tio.4oAlo.6oN was then deposited. The Tio.4oAlo.6oN layer was deposited by cathodic arc evaporation in a gas containing N2 using the mounted targets of Ti40AI60. The substrate bias voltage when depositing the Ti0.40AI0.60N layer was -70 V DC (relative to the chamber walls), the total pressure (N2) was 4 Pa, and the arc current for each cathode was 150 A. A Ti0.40AI0.60N layer having a thickness of about 2 pm was deposited on the inserts (measured on the flank 200 pm from the edge line). This formed the Sample 1 (1 a, 1 b) (invention).

[0116] In one of the separate runs (Sample 2) seen in Table 1 a V ion treatment step was performed. In this step an arc current of 170 A was applied to mounted V target in the PVD chamber, and a DC bias voltage level of -200 V were applied to the cutting tool blanks as seen in Table 2. Further information of Ar gas pressure, and treatment time are found in Table 2.

[0117] A layer of Ti0.40AI0.60N was then deposited. The Ti0.40AI0.60N layer was deposited by cathodic arc evaporation in a gas containing N2 using the mounted targets of Ti40AI60. The substrate bias voltage when depositing the Ti0.40AI0.60N layer was -70 V DC (relative to the chamber walls), the total pressure (N2) was 4 Pa, and the arc current for each cathode was 150 A. A Ti0.40AI0.60N layer having a thickness of about 2 pm was deposited on the inserts (measured on the flank 200 pm from the edge line). This formed the final Sample 2 (2a, 2b) (invention).

[0118] In one of the separate runs (Sample 3) seen in Table 1 a Cr ion treatment step was performed. In this step an arc current of 170 A was applied to mounted Cr target in the PVD chamber, and a DC bias voltage level of -200 V were applied to the cutting tool blanks as seen in Table 2. Further information of Ar gas pressure, and treatment time are found in Table 2.

[0119] A layer of Ti0.40AI0.60N was then deposited. The Ti0.40AI0.60N layer was deposited by cathodic arc evaporation in a gas containing N2 using the mounted targets of Ti40AI60. The substrate bias voltage when depositing the Ti0.40AI0.60N layer was -70 V DC (relative to the chamber walls), the total pressure (N2) was 4 Pa, and the arc current for each cathode was 150 A. A Ti0.40AI0.60N layer having a thickness of about 2 pm was deposited on the inserts (measured on the flank 200 pm from the edge line). This formed the final Sample 3 (3a, 3b) (invention).

[0120] In one of the separate runs (Sample 4) seen in Table 1 a Nb ion treatment step was performed. In this step an arc current of 170 A was applied to mounted Nb target in the PVD chamber, and a DC bias voltage level of -200

[0121] V were applied to the cutting tool blanks as seen in Table 2. Further information of Ar gas pressure, and treatment time are found in Table 2.

[0122] A layer of Tio.4oAlo.6oN was then deposited. The Tio.4oAlo.6oN layer was deposited by cathodic arc evaporation in a gas containing N2 using the mounted targets of Ti40AI60. The substrate bias voltage when depositing the Ti0.40AI0.60N layer was -70 V DC (relative to the chamber walls), the total pressure (N2) was 4 Pa, and the arc current for each cathode was 150 A. A Ti0.40AI0.60N layer having a thickness of about 2 pm was deposited on the inserts (measured on the flank 200 pm from the edge line). This formed the final Sample 4 (4a, 4b) (invention).

[0123] In one of the separate runs (Sample 5) seen in Table 1 a Mo ion treatment step was performed. In this step an arc current of 170 A was applied to mounted Mo target in the PVD chamber, and a DC bias voltage level of -200

[0124] V were applied to the cutting tool blanks as seen in Table 2. Further information of Ar gas pressure, and treatment time are found in Table 2.

[0125] A layer of Ti0.40AI0.60N was then deposited. The Ti0.40AI0.60N layer was deposited by cathodic arc evaporation in a gas containing N2 using the mounted targets of Ti40AI60. The substrate bias voltage when depositing the Ti0.40AI0.60N layer was -70 V DC (relative to the chamber walls), the total pressure (N2) was 4 Pa, and the arc current for each cathode was 150 A. A Ti0.40AI0.60N layer having a thickness of about 2 pm was deposited on the inserts (measured on the flank 200 pm from the edge line). This formed the final Sample 5 (5a, 5b) (invention).

[0126] In one of the separate runs (Sample 6) seen in Table 1 a Ti ion treatment step was performed. In this step an arc current of 170 A was applied to mounted Ti target in the PVD chamber, and a DC bias voltage level of -200 V were applied to the cutting tool blanks as seen in Table 2. Further information of Ar gas pressure, and treatment time are found in Table 2.

[0127] A layer of Cr0.30AI0.70N was then deposited. The Cr.030AI0.70N layer was deposited by cathodic arc evaporation in a gas containing N2 using the mounted targets of Cr30AI70. The substrate bias voltage when depositing the Cr.o.3oAlo.7oN layer was -150 V DC (relative to the chamber walls), the total pressure (N2) was 4 Pa, and the arc current for each cathode was 150 A. A Cro.3oAlo.7oN layer having a thickness of about 2 pm was deposited on the inserts (measured on the flank 200 pm from the edge line). This formed the final Sample 6 (6a, 6b) (invention).

[0128] In one of the separate runs (Sample 7) seen in Table 1 a Ti ion treatment step was performed. In this step an arc current of 150 A was applied to mounted Ti target in the PVD chamber, and a DC bias voltage level of -700 V were applied to the cutting tool blanks as seen in Table 2. Further information of Ar gas pressure, and treatment time are found in Table 2.

[0129] A layer of Cr0.30AI0.70N was then deposited. The Cr.030AI0.70N layer was deposited by cathodic arc evaporation in a gas containing N2 using the mounted targets of Cr30AI70. The substrate bias voltage when depositing the Cr.o.3oAlo.7oN layer was -150 V DC (relative to the chamber walls), the total pressure (N2) was 4 Pa, and the arc current for each cathode was 150 A. A Cr.o.3oAlo.7oN layer having a thickness of about 2 pm was deposited on the inserts (measured on the flank 200 pm from the edge line). This formed the final Sample 7 (7a, 7b) (comparative).

[0130] In one of the separate runs (Sample 8) seen in Table 1 a Cr ion treatment step was performed. In this step an arc current of 150 A was applied to mounted Cr target in the PVD chamber, and a DC bias voltage level of -700 V were applied to the cutting tool blanks as seen in Table 2. Further information of Ar gas pressure, and treatment time are found in Table 2.

[0131] A layer of Ti0.40AI0.60N was then deposited. The Ti0.40AI0.60N layer was deposited by cathodic arc evaporation in a gas containing N2 using the mounted targets of Ti40AI60. The substrate bias voltage when depositing the Ti0.40AI0.60N layer was -70 V DC (relative to the chamber walls), the total pressure (N2) was 4 Pa, and the arc current for each cathode was 150 A. A Ti0.40AI0.60N layer having a thickness of about 2 pm was deposited on the inserts (measured on the flank 200 pm from the edge line). This formed the final Sample 8 (8a, 8b) (comparative).

[0132] In one of the separate runs (Sample 9) a comparative sample was made by not performing any metal ion treatment step at all. A layer of Tio.4oAlo.6oN was deposited. The Tio.4oAlo.6oN layer was deposited by cathodic arc evaporation in a gas containing N2 using the mounted targets of Ti40AI60. The substrate bias voltage when depositing the Ti0.40AI0.60N layer was -70 V DC (relative to the chamber walls), the total pressure (N2) was 4 Pa, and the arc current for each cathode was 150 A. A Ti0.40AI0.60N layer having a thickness of about 2 pm was deposited on the inserts (measured on the flank 200 pm from the edge line). This formed the final Sample 9 (9a, 9b) (comparative). This sample is seen as a reference sample.

[0133] In one of the separate runs (Sample 10) a comparative sample was made by not performing any metal ion treatment step at all.

[0134] A layer of Cr0.30AI0.70N was then deposited. The Cr.030AI0.70N layer was deposited by cathodic arc evaporation in a gas containing N2 using the mounted targets of Cr30AI70. The substrate bias voltage when depositing the Cr.o.3oAlo.7oN layer was -150 V DC (relative to the chamber walls), the total pressure (N2) was 4 Pa, and the arc current for each cathode was 150 A. A Cr.o.3oAlo.7oN layer having a thickness of about 2 pm was deposited on the inserts (measured on the flank 200 pm from the edge line). This formed the final Sample 10 (10a, 10b) (comparative). This sample is seen as a reference sample.

[0135] Table 2.

[0136] Example 2 (TEM analysis):

[0137] TEM analysis was performed on the samples. The procedure as described herein under section "Methods" was followed.

[0138] STEM images were obtained as described herein and the interface region between the cemented carbide substrate body and the coating was studied.

[0139] An EDX intensity map over the interface was created for each of Samples 1 to 10. From each of these maps an EDX line scan profile was extracted.

[0140] In an EDX line scan the location of a line profile assigned to an element in the analysis may be seen as if a certain level of the element is present, forming a baseline intensity level, even when the element is actually not present at all. This is a result from the background estimation / fitting in the data handling procedure. This does, however, not affect the determination of the actual content of an element according to the method herein disclosed.

[0141] Fig. 4a / 4b each shows an EDX line scan for Sample 1 (invention) when going from within the coating into a WC grain.

[0142] Fig. 5a / 5b each shows an EDX line scan for Sample 2 (invention) when going from within the coating into a WC grain.

[0143] Fig. 6a / 6b each shows an EDX line scan for Sample 3 (invention) when going from within the coating into a WC grain.

[0144] Fig. 7a / 7b each shows an EDX line scan for Sample 4 (invention) when going from within the coating into a WC grain.

[0145] Fig. 8a / 8b each shows an EDX line scan for Sample 5 (invention) when going from within the coating into a WC grain. Fig. 9a / 9b each shows an EDX line scan for Sample 6 (invention) when going from within the coating into a WC grain.

[0146] In an intermediate zone between a WC grain and the coating there was a peak of Zr intensity seen in the EDX line scan for Sample 1 , a peak of V intensity seen in the EDX line scan for Sample 2, and a peak of Cr intensity seen in the EDX line scan for Sample 3.

[0147] In an intermediate zone between a WC grain and the coating there was a peak of Nb intensity seen in the EDX line scan for Sample 4, a peak of Mo intensity seen in the EDX line scan for Sample 5, and a peak of Ti intensity seen in the EDX line scan for Sample 6.

[0148] Also, in an intermediate zone between a WC grain and the coating there was a peak of Ti intensity seen in an EDX line scan for Sample 7 and a peak of Cr intensity seen in an EDX line scan for Sample 8.

[0149] Sample 9 and Sample 10 for which no metal ion treatment step had been used did not show any peak of an element Me3 being Ti, Cr, Zr, Mo, Nb or V, within an intermediate zone between the WC grain and the coating.

[0150] In the determination of contents of elements herein made, the number of passes was between 30-60 for Samples 1 to 3 and 9, and about 100 for Samples 4 to 8 and 10.

[0151] The average contents of the elements Me3 (Zr, V, Cr, Nb, Mo, or Ti ) and Ar, for the samples 1 to 8, within + / - 1 .0 nm from the peak of Zr, V, Cr, Nb, Mo, and Ti, respectively, were determined. The procedure as described herein under section "Methods" was followed. See results in Table 3.

[0152] Table 3.

[0153] Also, the average contents of the elements N, C, and W, for the samples 1 to 3 and 6, within + / - 1 .0 nm from the peak of Zr, V, Cr and Ti, respectively, were determined. The procedure as described herein under section "Methods" was followed. See results in Table 4. Table 4.

[0154] From the EDX line scans the full width at half maximum (FWHM) of the peak of Me3 intensity was determined. There may be some disturbances and / or signal noise in the EDX line scan. Therefore, when determining the max peak intensity and position of the peak of Me3, one should, if needed, consider the Me3 peak as overall smoothened.

[0155] From Fig. 4b which shows the EDX line scan for Sample 1 (invention), where Me3 is Zr, the Zr max peak position is at about 12.6 nm. The average baseline intensity of Zr in the coating between 6 and 11 nm from the Zr max peak position is about 2.0 counts. The peak intensity is about 16.1 counts.

[0156] Thus, the half-maximum intensity is about 9.1 counts. This gives an FWHM of about 3.1 nm.

[0157] From Fig. 5b which shows the EDX line scan for Sample 2 (invention), where Me3 is V, the V max peak position is at about 12.3 nm. The average baseline intensity of V in the coating between 6 and 11 nm from the V max peak position is about 3.0 counts. The peak intensity is about 19.3 counts. Thus, the half-maximum intensity is about 11 .2 counts. This gives a FWHM of about 2.3 nm.

[0158] From Fig. 6b which shows the EDX line scan for Sample 3 (invention), where Me3 is Cr, the Cr max peak position is at about 14.5 nm. The average baseline intensity of Cr in the WC grain between 6 and 11 nm from the Cr max peak position is about 0.2 counts. The peak intensity is about 14.1 counts. Thus, the half-maximum intensity is about 7.2 counts. This gives a FWHM of about 4.7 nm.

[0159] From Fig. 7b which shows the EDX line scan for Sample 4 (invention), where Me3 is Nb, the Nb max peak position is at about 13.5 nm. The average baseline intensity of Nb in the WC grain between 6 and 11 nm from the Nb max peak position is about 1.1 counts. The peak intensity is about 46.1 counts. Thus, the half-maximum intensity is about 22.5 counts. This gives a FWHM of about 2.2 nm.

[0160] From Fig. 8b which shows the EDX line scan for Sample 5 (invention), where Me3 is Mo, the Mo max peak position is at about 12.7 nm. The average baseline intensity of Mo in the WC grain between 6 and 11 nm from the Mo max peak position is about 2.5 counts. The peak intensity is about 39.5 counts. Thus, the half-maximum intensity is about 21 counts. This gives a FWHM of about 2.2 nm.

[0161] From Fig. 9b which shows the EDX line scan for Sample 6 (invention), where Me3 is Ti, the Ti max peak position is at about 14 nm. The average baseline intensity of Ti in the WC grain between 6 and 11 nm from the Ti max peak position is about 14 counts. The peak intensity is about 256 counts. Thus, the half-maximum intensity is about 135 counts. This gives a FWHM of about 3.6 nm.

[0162] Over a distance starting at 6 nm and ending at 11 nm from the Me3 max peak position in the EDX line scan, in the direction into the coating, the average content of Me3 is for each of Samples 1 to 6 the following:

[0163] Sample 1 (Me3=Zr): 0.9 at%.

[0164] Sample 2 (Me3=V): 0.4 at%. Sample 3 (Me3=Cr): 0.0 at%.

[0165] Sample 4 (Me3=Nb): 0.1 at%.

[0166] Sample 5 (Me3=Mo): 0.2 at%.

[0167] Sample 6 (Me3=Ti): 0.1 at%.

[0168] The occupancy of the uppermost WC interface of a total interface between the cemented carbide substrate body and the coating of the samples was considered to be about 90-95%.

[0169] Furthermore, the deposited Tio.4oAlo.6oN layer and the deposited CrsoAFoN layer in the samples is are both of cubic NaCI structure.

[0170] Also, within + / - 1 .0 nm from the Me3 max peak position in the EDX line scan the intermediate zone of Samples 1-6 is crystalline with lattice fringes connecting to substrate or coating or both depending on relative grain orientation in the hexagonal WC-grains and cubic coating grains.

[0171] Example 3:

[0172] Cutting tests were made in order to determine the performance of the samples made.

[0173] Explanations to terms used:

[0174] The following expressions / terms are commonly used in metal cutting, but nevertheless explained in the table below:

[0175] Vc (m / min): cutting speed in meters per minute fz (mm / tooth): feed rate in millimeter per tooth (in milling) fn (mm / rev) feed rate per revolution (in turning) z: (number) number of teeth in the cutter ae(mm): radial depth of cut in millimeter ap(mm): axial depth of cut in millimeter Last stage machining (LSM):

[0176] Longitudinal turning

[0177] Work piece material: Inconel 718 aged, Hardness 428HB, D=180, L=600 mm, Holder: C5-DCLNL-35060-12, KAPR1=95° Vc=30 m / min fn=0.11 mm / rev ap=0.2 mm with external cutting fluid

[0178] The tool life criteria is a max flank wear (notch), VB of 0.2 mm on secondary cutting edge.

[0179] Flaking resistance:

[0180] The evaluation was made through turning test in austenitic steel. In order to provoke adhesive wear and flaking of the coating the depth of cut apwas varied between 4 to 0 and 0 to 4 mm (in one run during radial facing). The inserts were evaluated through SEM analysis where flaked area was guantified through image treatment regarding of degree of white areas (being exposed WC after coating flaking).

[0181] Operation: Facing (turning)

[0182] Work piece material: Bar of austenitic stainless steel Sanmac 316L, L=200 mm, D=100 mm, -215 HB

[0183] Holder: C5-DCLNL-35060-12, KAPR1=95°

[0184] Insert type: CNMG 120408-MM

[0185] Depth of cut ap= 4 to 0, 0 to 4 mm

[0186] Cutting speed Vc= 100 m / min

[0187] Feed rate fz= 0.36 mm / rev

[0188] Cooling: yes, external Edge line toughness (ELT):

[0189] Operation: 12 mm deep entrances in the material. The cutter body moves laterally 12 mm between each entrance.

[0190] Work piece material: Dievar unhardened, P3. O.Z.AN, 617*207*100 mm

[0191] Tool holder: R390-032C5-11 M, Dc=32 mm, overhang: 95 mm

[0192] Insert: R390-11T308M-PM z=1

[0193] Vc=215 m / min fz=0.15 mm ae=12 mm ap=3.0 length of cut=12mm without cutting fluid

[0194] The cut-off criteria are chipping of at least 0.5 mm of the edge line Tool life is presented as the number of cut entrances in order to achieve these criteria.

[0195] In the tables presenting the results from the different tests there is a notation under the sample number which metal was used in the metal ion treatment and in some cases some further information.

[0196] Samples 1 to 5, and a first Sample 9, 9*, are run within the same test seguence, "loop", and the results can be compared with each other. Results from comparative sample 9* are marked with *.

[0197] Samples 8 and a second Sample 9, 9**, are run within the same test seguence, "loop", and the results can be compared with each other. Results from comparative sample 9** are marked with **.

[0198] Samples 6, 7 and comparative sample 10 are run within the same test seguence, "loop", and the results can be compared with each other. Results from comparative sample 10 are marked with ***. Last stage machining (LSM): Table5.

[0199]

[0200] * to be compared with Samples 1 to 5

[0201] ** to be compared with Sample 8

[0202] *** to be compared with Samples 6 and 7

[0203] Turning operations of ISO-M workpiece materials, flaking resistance:

[0204] Table 6.

[0205]

[0206] * to be compared with Samples 1 to 5

[0207] ** to be compared with Sample 8

[0208] *** to be compared with Samples 6 and 7 Milling operation, edge line toughness (ELT):

[0209] Table 7.

[0210]

[0211] * to be compared with Samples 1 to 5

[0212] ** to be compared with Sample 8

[0213] *** to be compared with Samples 6 and 7

Claims

Claims1 . A coated cutting tool (1 ) for metal machining comprising a rake face (2), a flank face (3) and a cutting edge (4) inbetween, the coated cutting tool (1 ) further comprises a cemented carbide substrate body (5) and a coating (6) thereon, wherein the coating (6) comprises a from 0.2 to 15 pm thick layer of Me1 N, wherein Me1 is one or more metals of group 4 to 6 in the periodic table of elements or one or more metals of group 4 to 6 in the periodic table of elements in combination with Al and / or Si,-the cemented carbide comprises WC, in the form of WC grains, within a binder phase,- there is an uppermost part of the cemented carbide substrate body (5) wherein there are uppermost WC grains adjacent to the coating (6), there is an intermediate zone between an uppermost part of said WC grains and the coating (6) comprising a peak of Me3 intensity in an EDX line scan made from within the coating (6) into a WC grain perpendicular to the surface plane of the WC grain, Me3 is one of Ti, Cr, Zr, Mo, Nb and V, the average content of Me3 within + / - 1 .0 nm from the Me3 max peak position is from 2 to 30 at%, the Me3 within + / - 1 .0 nm from the Me3 max peak position in the EDX line scan is present as a metal nitride or carbonitride,- the average content of any noble gas element or combination of noble gas elements, within + / - 1.0 nm from the Me3 max peak position in the EDX line scan, is <0.6 at%.

2. A coated cutting tool (1 ) according to claim 1 , wherein Me3 is one of Cr, Cr, Zr, Mo, Nb and V.

3. A coated cutting tool (1 ) according to any one of claims 1 -2, wherein Me3 is one of Zr, Mo, Nb and V.

4. A coated cutting tool (1 ) according to any one of claims 1 -3, wherein Me3 is one of Mo and V.

5. A coated cutting tool (1 ) according to any one of claims 1 -4, wherein the average content of any noble gas element or combination of noble gas elements, within + / - 1 .0 nm from the Me3 max peak position in the EDX line scan, is <0.3 at%.

6. A coated cutting tool (1 ) according to any one of claims 1 -5, wherein the peak of Me3 intensity in the EDX line scan has a full width at half maximum (FWHM), as determined from the average baseline intensity of Me3 in the coating (6) between 6 and 11 nm from the Me3 max peak position, of from 1 .0 to 6.0 nm, preferably from 1 .5 to 5.0 nm.

7. A coated cutting tool (1 ) according to any one of claims 1 -6, wherein, in the Me1 N layer, Me1 is one or more of Ti, Cr and Zr, or one or more of Ti, Cr and Zr in combination with Al and / or Si.

8. A coated cutting tool (1 ) according to any one of claims 1 -7, wherein, the Me1 N layer is a monolithic layer.

9. A coated cutting tool (1 ) according to any one of claims 1 -7, wherein, the Me1 N is a multilayer of alternating sub-layers (MeaiN, Mea2N, ...MeanN), n is a number from 2 to 5, or from 2 to 4, or from 2 to 3, of different elemental composition. Meai, Mea2, ...Meanare each one or more of metals of group 4 to 6 in the periodic table of elements or one or more metals of group 4 to 6 in the periodic table of elements in combination with Al and / or Si.

10. A coated cutting tool (1 ) according to any one of claims 1 -9, wherein over a distance starting at 6 nm and ending at 11 nm from the max peak position ofMe3 in the EDX line scan, in the direction into the coating (6), the average content of Me3 is at most 2 at%.

11. A coated cutting tool (1 ) according to claim 10, wherein over a distance starting at 6 nm and ending at 11 nm from the max peak position of Me3 in the EDX line scan, in the direction into the coating (6), the coating (6) comprises (Me2xSiyAlz)N, wherein Me2 is one or more metals of group 4 to 6 in the periodic table of elements, 0.25<x<1 , 0<y<0.3, 0<z<0.75, x+y+z=1.

12. A coated cutting tool (1) according to claim 11 , wherein Me2 is different from Me3.

13. A coated cutting tool (1 ) according to any one of claims 1 -12, wherein within + / - 1 .0 nm from the Me3 max peak position in the EDX line scan, there is N, C and W present, the average content of N within + / - 1 .0 nm from the Me3 max peak position in the EDX line scan, is from 15 to 40 at%, the average content of C within + / - 1 .0 nm from the Me3 max peak position in the EDX line scan, is from 5 to 25 at%, the average content of W within + / - 1 .0 nm from the Me3 max peak position in the EDX line scan, is from 15 to 45 at%.

14. A coated cutting tool (1 ) according to any one of claims 1 -13, wherein the binder phase in the cemented carbide is a metal binder being Co, the metal binder content in the cemented carbide is from 5 to 18 wt%.

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

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