COATED CUTTING TOOL
20240207945 ยท 2024-06-27
Inventors
Cpc classification
B23B27/148
PERFORMING OPERATIONS; TRANSPORTING
C23C14/35
CHEMISTRY; METALLURGY
International classification
B23B27/14
PERFORMING OPERATIONS; TRANSPORTING
Abstract
A coated cutting tool has at least one rake face and at least one flank face and a cutting edge therebetween. The coated cutting tool includes a substrate and a coating. The coating includes a (Ti,Al)N layer. The (Ti,Al)N layer is either a single monolithic layer or a multilayer of two or more alternating (Ti,Al)N sub-layer types having different compositions. The (Ti,Al)N layer has an overall atomic ratio Al/(Ti+Al) of >0.67 but ?0.85, wherein the (Ti,Al)N layer shows a plane strain modulus distribution along a direction perpendicular to a cutting edge on the rake face and/or the flank face. The plane strain modulus at a point at a distance of 0.5 mm from a point at the cutting edge is more than 85% of the plane strain modulus at the cutting edge, with the plane strain modulus at the cutting edge being ?450 GPa.
Claims
1. A coated cutting tool having at least one rake face and at least one flank face and a cutting edge therebetween, the coated cutting tool comprising: a substrate; and a coating, the coating including a (Ti,Al)N layer, the (Ti,Al)N layer being either a single monolithic layer or a multilayer of two or more alternating (Ti,Al)N sub-layer types having different compositions, the (Ti,Al)N layer having an overall atomic ratio Al/(Ti+Al) of >0.67 but ?0.85, wherein the (Ti,Al)N layer shows a plane strain modulus distribution along a direction perpendicular to a cutting edge on the rake face and/or the flank face, the plane strain modulus at a point at a distance of at least 0.5 mm from a point at the cutting edge is at least more than 85% of the plane strain modulus at the cutting edge, the plane strain modulus at the cutting edge being ?450 GPa.
2. The coated cutting tool according to claim 1, wherein the (Ti,Al)N layer shows a plane strain modulus distribution along the direction perpendicular to the cutting edge on the rake face and/or the flank face, the plane strain modulus at a point at a distance of 1 mm from a point at the cutting edge being more than 85% of the plane strain modulus at the cutting edge.
3. The coated cutting tool according to claim 1, wherein the (Ti,Al)N layer shows a hardness distribution along the direction perpendicular to the cutting edge on the rake face and/or the flank face, the hardness at the point at the distance of 0.5 mm from the point at the cutting edge is more than 70% of the hardness at the cutting edge, the Vickers hardness at the cutting edge being ?3000 HV (15 mN load).
4. The coated cutting tool according to claim 1, wherein the (Ti,Al)N layer shows a hardness distribution along the direction perpendicular to the cutting edge on the rake face and/or the flank face, the hardness at a point at a distance of 1 mm from a point at the cutting edge being more than 70% of the hardness at the cutting edge, the Vickers hardness at the cutting edge being ?3000 HV (15 mN load).
5. The coated cutting tool according to claim 1, wherein the (Ti,Al)N layer has a plane strain modulus at the cutting edge of ?475 GPa.
6. The coated cutting tool according to claim 1, wherein the (Ti,Al)N layer has a Vickers hardness at the cutting edge of 3500-4300 HV (15 mN load).
7. The coated cutting tool according to claim 1, wherein the (Ti,Al)N layer has a thickness of from 0.1 to 15 ?m.
8. The coated cutting tool according to claim 1, wherein the (Ti,Al)N layer shows a distribution of 111 misorientation angles, a 111 misorientation angle being the angle between a normal vector to the surface of the (Ti,Al)N layer and the <111> direction that is closest to the normal vector to the surface of the (Ti,Al)N layer, a cumulative frequency distribution of the 111 misorientation angles being such that ?60% of the 111 misorientation angles are less than 10 degrees.
9. The coated cutting tool according to claim 1, wherein the (Ti,Al)N layer has an overall atomic ratio Al/(Ti+Al) of 0.70-0.80.
10. The coated cutting tool according to claim 1, wherein the (Ti,Al)N layer is a single monolithic layer.
11. The coated cutting tool according to claim 1, wherein the multilayer of two or more alternating (Ti,Al)N sub-layer types having different compositions has at least one (Ti,Al)N sub-layer type having an atomic ratio Al/(Ti+Al) of 0.50-0.67 and at least one (Ti,Al)N sub-layer type having an atomic ratio Al/(Ti+Al) of 0.70-0.90.
12. The coated cutting tool according to claim 11, wherein the (Ti,Al)N sub-layer type in a multilayer has an average thickness of 1-100 nm.
13. The coated cutting tool according to claim 1, wherein the (Ti,Al)N layer is of a single phase cubic B1 crystal structure, at least over a distance of 1 mm from the point at the cutting edge along the direction perpendicular to the cutting edge on the rake face and/or the flank face.
14. The coated cutting tool according to claim 1, wherein the substrate is selected from cemented carbide, cermet, cubic boron nitride (cBN), ceramics, polycrystalline diamond (PCD) and high speed steel (HSS).
15. The coated cutting tool according to claim 1, which is in the form of an insert, a drill or an end mill.
Description
BRIEF DESCRIPTIONS OF THE DRAWINGS
[0046]
[0047]
[0048]
[0049]
[0050]
[0051]
[0052]
[0053]
[0054]
[0055]
[0056]
[0057]
[0058]
[0059]
[0060]
[0061]
[0062]
DETAILED DESCRIPTION OF EMBODIMENTS IN DRAWINGS
[0063]
[0064]
[0065]
Methods
Electron Back Scattering Diffraction (EBSD):
[0066] The EBSD measurements were performed on the flank face of the cutting tool samples at a distance of 50 ?m from the cutting edge.
[0067] Prior to the EBSD scans the respective sample surfaces were carefully polished using a colloidal silica suspension with a nominal grain size of 40 nm (Struers OPS 0.04 ?m). This step serves to remove any roughness present on the as deposited coating surface. No more than 100 nm of the top coating is removed by this procedure.
[0068] If the (Ti,Al)N layer would not have been the uppermost layer of the coating, a suitable method, such as polishing, is used for removing the layer(s) situated above the (Ti,Al)N layer, in order to eventually provide a polished (Ti,Al)N surface for the EBSD scans.
[0069] The electron diffraction patterns were acquired in a Zeiss CrossBeam 540 FIB-SEM (Carl Zeiss AG, Oberkochen, Germany) in conjunction with an EDAX DigiView 5 EBSD camera (EDAX Inc., Mahwah NJ, USA) at a standard sample tilt of 70? and a working distance of 5 mm. An e-beam acceleration voltage of 10 to 13 kV was used for the acquisition. The step size for the mappings was 20 nm. The mapping area was 15.00?11.25 ?m.
[0070] Indexed via the EDAX TEAM software, the determined crystal orientation data was further evaluated using the EDAX OIM Analysis software.
[0071] A cumulative frequency distribution of 111 misorientation angles was calculated as follows: For each spot measurement of the total EBSD scan (representing an incremental surface area of the overall analyzed surface region) the crystallographic direction perpendicular to the surface plane of the (Ti,Al)N layer, is derived from the absolute crystallographic orientation measured (i.e. the orientation data in Euler angles).
[0072] Subsequently, the vector angle between this crystallographic direction and the closest <111>-type direction is calculated. Where closest refers to the <111>-type direction (among all four crystallographically equivalent possibilities) that includes the smallest possible angle with the surface normal. This angle is defined as the 111 misorientation angle. As each measurement point constitutes an equal fraction of the analyzed area the relative frequency distribution of these angular misorientation values characterizes the overall degree of the 111 surface texture.
Electron Diffraction in Transmission Electron Microscopy (TEM):
[0073] In the electron diffraction analysis made herein these are TEM measurements which were carried out using a Transmission Electron Microscope: JEOL ARM 200F microscope, 200 kV. Only the coating should contribute to the diffraction pattern by using a selected area aperture. The TEM was operated with parallel illumination for the diffraction in a selected area electron diffraction (SAED) procedure.
[0074] The samples were analysed in cross-section, i.e., the incident electron beam was parallel to the film plane. To rule out an amorphisation during sample preparation different methods can be used, i) classical preparation including mechanical cutting, gluing, grinding and ion polishing and ii) using a FIB to cut the sample and make a lift out to make the final polishing. The position of the analysis was near the substrate, about 200 nm from the substrate.
[0075] SAED data were obtained for the samples. From the SAED data a diffraction intensity profile was provided along the 111 ring that is centered around the angular position that corresponds to the coating normal. Then normalized integrations were made both at the 111 diffraction spot and the ?1?1?1 diffraction spot, respectively, going to 45 degrees misorientation angle. The two integrations were combined into one intensity distribution curve. The intensity distribution data from both the 111 diffraction spot and the ?1?1?1 diffraction spot were used in order to increase the number of data points thereby reducing the signal to noise ratio as much as possible.
[0076] The intensity at a certain misorientation angle is directly proportional to the sample volume that exhibits this misorientation. Thus, the intensity distribution curve is equivalent to the distribution of 111 misorientation angles. Then, correspondingly, a cumulative intensity curve obtained from the intensity distribution curve is equivalent to a cumulative frequency distribution of 111 misorientation angles.
X-Ray Diffraction:
[0077] The X-ray diffraction patterns were acquired by Grazing incidence mode (GID) on a diffractometer from Seifert/GE (PTS 3003). Cu-K?-radiation with a polycapillary lens (for producing a parallel beam) was applied for the analysis (high tension 40 kV, current 40 mA). The incident beam was defined by a 0.5 mm pinhole. For the diffracted beam path an energy dispersive detector (Meteor OD) was used. The measurement was done in grazing incidence mode (Omega=4?). The 2theta range was about 20-80? with a step size of 0.03? and a counting time of 6 s.
Vickers Hardness:
[0078] The Vickers hardness was measured by means of nano indentation (load-depth graph) using a Picodentor HM500 of Helmut Fischer GmbH, Sindelfingen, Germany. For the measurement and calculation the Oliver and Pharr evaluation algorithm was applied, wherein a diamond test body according to Vickers was pressed into the layer and the force-path curve was recorded during the measurement. The maximum load used was 15 mN (HV 0.0015), the time period for load increase and load decrease was 20 seconds each. From this curve hardness was calculated.
Plane Strain Modulus:
[0079] The elastic properties of the coating samples were characterized by the so-called plane strain modulus Eps as derived by nanoindentation via the Oliver and Pharr method. The nano-indentation data was obtained from indentation as described for Vickers hardness above.
[0080] The distance 1 mm from the cutting edge used herein refers to a distance 1 mm from the beginning of the cutting edge (i.e., where the edge rounding begins)
Grain Width:
[0081] The average (Ti,Al)N grain width was determined through the evaluation of SEM cross-sections by the stereological line intersection method: A line grid is overlaid to a SEM micrograph and the intersections of the lines with the grain boundary network are marked. The statistics of the distances between adjacent intersections reflect the size of the three-dimensional grains (see, e.g., B. Ilschner, R. F. Singer, Werkstoffwissenschaften und Fertigungstechnik, Springer Berlin Heidelberg, 2016, ISBN: 978-3-642-53891-9). The SEM micrographs were taken at a distance of about 0.7 ?m from the cutting edge, on the flank face.
EXAMPLES
Example 1 (Effect of Total Pressure)
[0082] A layer of (Ti,Al)N was deposited onto WCCo based substrates using a target set-up of one target with the composition Ti.sub.0.33Al.sub.0.67 and one target with the composition Ti.sub.0.20Al.sub.0.80. The WCCo based substrates were square-shaped inserts of flat geometry for easier analysis of the coating. The substrates had a composition of 8 wt % Co and balance WC.
[0083] HIPIMS mode was used in a Hauzer Flexicoat 1000 equipment. In three separate runs of depositions the total pressure was varied while keeping all other conditions the same. Three different total pressures were tested, 0.505 Pa, 0.219 Pa and 0.167 Pa. The intention was to study the influence of total pressure on hardness distribution and plane strain modulus distribution along a distance from the cutting edge.
[0084] The following process parameters were used:
TABLE-US-00001 Temperature: 300? C. Average power: 40 kW (20 kW per target) Pulse duration: .sup.80 ?s Set peak current: Target 1: 800 A, target 2: 800 A DC pulse voltage: 1800 V Ar-Flow: 500 sccm 180 sccm 130 sccm Total pressure 0.505 Pa 0.219 Pa 0.167 Pa (N.sub.2 + Ar): (~167 sccm (~115 sccm (~108 sccm N.sub.2) N.sub.2) N.sub.2) Bias Potential: ?100 V
[0085] (Ti,Al)N layers with a thickness of about 1.75 ?m were deposited. From the substrate rotation speed an average thickness of a (Ti,Al)N sublayer was calculated to be about 3 nm.
[0086] The coated cutting tools provided are called Sample 1 (0.505 Pa), Sample 2 (0.219 Pa) and Sample 3 (0.167 Pa).
[0087] Hardness measurements (load 15 mN) were carried out in the middle between two nose radiuses, from the edge between a rake face and a flank face in a direction perpendicular to the edge on the flank face of the coated cutting tools. Values of Vickers hardness and plane strain modulus (Eps) were determined.
Example 2 (Effect of Temperature)
[0088] In order to study the effect of temperature on hardness distribution and plane strain modulus distribution along a distance from the cutting edge two further samples were made. A layer of (Ti,Al)N was deposited onto WCCo based substrates using a target set-up of one target with the composition Ti.sub.0.33Al.sub.0.67 and one target with the composition Ti.sub.0.20Al.sub.0.80. The WCCo based substrates were square-shaped inserts of flat geometry for easier analysis of the coating. The substrates had a composition of 8 wt % Co and balance WC.
[0089] HIPIMS mode was used in a Hauzer Flexicoat 1000 equipment. In two separate runs of depositions using a combination of a total pressure of 0.219 Pa and at a temperature of 350 and 400? C., respectively. All other process parameters were the same as used in Example 1,
[0090] (Ti,Al)N layers with a thickness of about 1.75 ?m were deposited. From the substrate rotation speed an average thickness of a (Ti,Al)N sublayer was calculated to be about 3 nm.
[0091] The coated cutting tools provided are called Sample 4 and Sample 5.
[0092] Hardness measurements (load 15 mN) were now carried out near a nose radius, from the cutting edge in a direction perpendicular to the cutting edge line on the flank face of the coated cutting tools Sample 2, deposited at 300? C., Sample 4, deposited at 350? C., and Sample 5, deposited at 400? C. In this case the inserts have a nose radius of 1 mm and by near a nose radius is meant that the hardness measurements were made at the beginning of the nose radius. Values of plane strain modulus (Eps) and Vickers hardness were determined.
[0093] It is seen that the lowest temperature, 300? C., gives an even level of Vickers hardness and plane strain modulus along a distance perpendicular to the cutting edge line while deposition at 350? C. or 400? C. gives a coating that shows declining Vickers hardness and plane strain modulus values when moving away from the cutting edge.
[0094] Sample 2 and Sample 4 lie within the invention.
Further Conclusions from Example 1 and Example 2
[0095] It should be noted that when comparing Sample 2 as measured in the middle between two nose radiuses (Example 1) and Sample 2 as measured near a nose radius (Example 2) one sees that for the same total pressure of 0.219 Pa a sustained high level of Vickers hardness and plane strain modulus along a distance from the cutting edge are provided near a nose radius but not along a distance from the edge in the middle of two nose radiuses. This is because, in addition to a concentration of the electrical field at the cutting edge, there is a corner effect at the nose radius in terms of a local concentration of the electrical field.
[0096] In a metal cutting process the important active area in a cutting process is the area near a nose radius. Thus, it is concluded that both Sample 2 and Sample 3 are samples within the present invention. Sample 1 shows a very sharp decrease in hardness and plane strain modulus when going away from the edge and even if the measurement was made in the middle between two nose radiuses also a measurement near a nose radius gives a similar hardness and plane strain modulus distribution profile. Sample 1 is therefore considered to be outside the present invention.
Example 3
[0097] A further sample corresponding to Sample 2 (invention) was made with a higher thickness (7.3 ?m). The process parameters were:
TABLE-US-00002 Temperature: 300? C. Average power: 40 kW (20 kW per target) Pulse duration: 80 ?s Set peak current: Target 1: 800 A, target 2: 800 A DC pulse voltage: 1800 V Ar-Flow: 180 sccm Total pressure (N.sub.2 + Ar): 0.22 Pa (~115 sccm N.sub.2) Bias Potential: ?110 V
[0098] The coated cutting tool provided is called Sample 2a.
Example 4
[0099] A layer of (Ti,Al)N, single monolithic layer, was deposited onto WCCo based substrates using a target set-up of one target with the composition Ti.sub.0.20Al.sub.0.80. The WCCo based substrates were inserts of flat geometry for easier analysis of the coating. The substrates had a composition of 8 wt % Co and balance WC.
[0100] HIPIMS mode was used in a Hauzer Flexicoat 1000 equipment.
[0101] The following process parameters were used:
TABLE-US-00003 Temperature: 200? C. Average power: 20 kW Pulse duration: 80 ?s Set peak current: 800 A DC pulse voltage: 1800 V Ar-Flow: 150 sccm Total pressure (N.sub.2 + Ar): 0.190 Pa (~88 sccm N.sub.2) Bias Potential: ?150 V
[0102] A (Ti,Al)N layer with a thickness of about 1.7 ?m was deposited on the inserts.
[0103] The coated cutting tools provided are called Sample 6 (invention).
[0104]
Example 5 (Comparisons with Ti40Al60N and Effect of Bias Increase Only)
[0105] Coated cutting tool inserts of three types were made as references wherein the coatings were either a Ti.sub.0.40Al.sub.0.60N layer (Sample 7), a Ti.sub.0.27Al.sub.0.73N layer deposited at std pressure and ?40 V bias (Sample 8) and a Ti.sub.0.27Al.sub.0.73N layer deposited at std pressure and ?110 V bias (Sample 9). The coatings were deposited onto WCCo based substrates being flat inserts (for easier analysis of the coating) using HIPIMS mode in an Oerlikon Balzers equipment using S3p technology.
[0106] The substrates had a composition of 8 wt % Co and balance WC.
[0107] The deposition process was run in HIPIMS mode using the following process parameters
TABLE-US-00004 Target material: Ti.sub.0.40Al.sub.0.60 // Ti.sub.0.27Al.sub.0.73 Target size: 6 ? circular, diameter 15 cm Average power per target: 9 kW Peak pulse power: 55 kW Pulse on time: 4 ms Temperature: 430? C. Total pressure: 0.61 Pa Argon pressure: 0.43 Pa Bias potential: ?40 V (for sample with Ti.sub.0.40Al.sub.0.60 target and one sample with Ti.sub.0.27Al.sub.0.73 target) Bias potential: ?110 V (for one sample with Ti.sub.0.27Al.sub.0.73 target)
[0108] Each sample had a layer thickness of about 3 ?m deposited.
[0109] The coated cutting tools provided were called Sample 7, Sample 8 and Sample 9.
[0110] In addition a sample was made corresponding to Sample 2 (invention). HIPIMS mode was used in a Hauzer Flexicoat 1000 equipment.
[0111] The process parameters were:
TABLE-US-00005 Temperature: 300? C. Average power: 40 kW (20 kW per target) Pulse duration: 80 ?s Set peak current: Target 1: 800 A, target 2: 800 A DC pulse voltage: 1800 V Ar-Flow: 180 sccm Total pressure (N.sub.2 + Ar): 0.22 Pa (~115 sccm N.sub.2) Bias Potential: ?110 V
[0112] A layer thickness of about 3 ?m was deposited.
[0113] From the substrate rotation speed an average thickness of a (Ti,Al)N sublayer was calculated to be about 3 nm.
[0114] The coated cutting tool provided was called Sample 10.
[0115]
[0116]
[0117]
[0118]
[0119]
[0120] As expected the low-Al Ti.sub.0.40Al.sub.0.60N layer (Sample 7) shows high plane strain modulus over a distance of at least 1 mm from the cutting edge. Also the Vickers hardness was high over this distance.
[0121] The Ti.sub.0.27Al.sub.0.73N layer deposited at std pressure and ?40 V bias voltage (Sample 8) shows very low (?250 GPa) plane strain modulus everywhere from the cutting edge and over a distance in a direction away from the cutting edge. Also the Vickers hardness is very low (about 2000 HV). This suggests an almost fully hexagonal coating which was also confirmed by XRD analysis.
[0122] The Ti.sub.0.27Al.sub.0.73N layer deposited at std pressure and ?110 V bias voltage (Sample 9) shows a high plane strain modulus (about 460 GPa) on the cutting edge. Also, the Vickers hardness is high over this distance (about 2800 HV). However, both the hardness and plane strain modulus decreases over a distance in a direction away from the cutting edge. At a distance of 1 mm from the cutting edge the Vickers hardness is only about 2300 HV and the plane strain modulus is only about 320 GPa.
[0123] However, it is concluded that just increasing the bias voltage indeed provides a high hardness and high modulus structure for the Ti.sub.0.27Al.sub.0.73N layer but only at the cutting edge so any coating as desired in the present invention is not provided.
[0124] The (Ti,Al)N layer according to the invention (Sample 10), however, shows a high level of plane strain modulus and hardness over the whole distance to 1 mm from the cutting edge.
Example 6
[0125] An even further sample according to the invention was made intended for testing in metal cutting. A first layer of 1.3 ?m conventional Ti.sub.0.40Al.sub.0.60N deposited by cathodic arc evaporation was provided onto a WCCo based substrate followed by a 1.25 ?m (Ti,Al)N layer very similar to the (Ti,Al)N layer of Sample 2. The WCCo based substrate was of two different milling insert geometries, SPMW12 and ADMT160608R-F56. The substrate had a composition of 8 wt % Co and balance WC.
[0126] The main purpose of the arc-evaporation deposited innermost layer is to improve adhesion to the substrate so that tool life is not limited by flaking. The two layers were made as follows:
Innermost layer of Ti.sub.0.40Al.sub.0.60N:
[0127] A 1.3 ?m layer of Ti.sub.0.40Al.sub.0.60N was deposited onto a WCCo based substrate using a target with the composition Ti.sub.0.40Al.sub.0.60.
[0128] Arc mode was used in a Hauzer Flexicoat 1000 equipment. The deposition was run at total pressure 5 Pa, DC bias ?40 V and temperature 580? C.
Layer of (Ti,Al)N:
[0129] A 1.25 ?m layer of (Ti,Al)N was deposited onto the arc-deposited Ti.sub.0.40Al.sub.0.60N layer using a target set-up of one target with the composition Ti.sub.0.33Al.sub.0.67 and one target with the composition Ti.sub.0.20Al.sub.0.80. HIPIMS mode was used in a Hauzer Flexicoat 1000 equipment.
[0130] The following process parameters were used:
TABLE-US-00006 Temperature: 300? C. Average power: 40 kW (20 kW per target) Pulse duration: 80 ?s Set peak current: Target 1: 800 A, target 2: 800 A DC pulse voltage: 1800 V Ar-Flow: 180 sccm Total pressure (N.sub.2 + Ar): 0.22 Pa (~115 sccm N.sub.2) Bias Potential: ?100 V
[0131] From the substrate rotation speed an average thickness of a (Ti,Al)N sublayer was calculated to be about 3 nm.
[0132] The resulting coated cutting tool is called Sample 11 (invention).
[0133] Table 1 shows a summary of the samples made.
TABLE-US-00007 TABLE 1 (Ti, Al)N layer in Average coating composition Comments Sample 1 multi- Ti.sub.0.33Al.sub.0.67N/ Ti.sub.0.27Al.sub.0.73N 0.50 Pa, 300? C. (comparative) Ti.sub.0.20Al.sub.0.80N Sample 2 multi- Ti.sub.0.33Al.sub.0.67N/ Ti.sub.0.27Al.sub.0.73N 0.22 Pa, 300? C. (invention) Ti.sub.0.20Al.sub.0.80N Sample 3 multi- Ti.sub.0.33Al.sub.0.67N/ Ti.sub.0.27Al.sub.0.73N 0.17 Pa, 300? C. (invention) Ti.sub.0.20Al.sub.0.80N Sample 4 multi- Ti.sub.0.33Al.sub.0.67N/ Ti.sub.0.27Al.sub.0.73N 0.22 Pa, 350? C. (invention) Ti.sub.0.20Al.sub.0.80N Sample 5 multi- Ti.sub.0.33Al.sub.0.67N/ Ti.sub.0.27Al.sub.0.73N 0.22 Pa, 400? C. (comparative) Ti.sub.0.20Al.sub.0.80N Sample 6 Ti.sub.0.20Al.sub.0.80N Ti.sub.0.20Al.sub.0.80N monolithic single (invention) layer Sample 7 Ti.sub.0.40Al.sub.0.60N Ti.sub.0.40Al.sub.0.60N (comparative) Sample 8 Ti.sub.0.27Al.sub.0.73N Ti.sub.0.27Al.sub.0.73N 0.61 Pa, ?40 V (comparative) Sample 9 Ti.sub.0.27Al.sub.0.73N Ti.sub.0.27Al.sub.0.73N 0.61 Pa, ?110 V (comparative) Sample 10 multi- Ti.sub.0.33Al.sub.0.67N/ Ti.sub.0.27Al.sub.0.73N 0.22 Pa, 300? C. (invention) Ti.sub.0.20Al.sub.0.80N Sample 11 multi- Ti.sub.0.33Al.sub.0.67N/ Ti.sub.0.27Al.sub.0.73N 0.22 Pa, 300? C. (invention) Ti.sub.0.20Al.sub.0.80N
Example 7 (Analysis)
XRD:
[0134] XRD analysis was made on Sample 1 (comparative), Sample 2 (invention), Sample 3 (invention), and Sample 6 (invention).
[0135] All four samples show peaks from the cubic (111), (200) and (220) planes. However, Sample 1 (outside invention) in addition shows significant peaks at about 57 and 70 degrees 2theta, the peaks being the hexagonal (110) (hex AlN 57.29?), and one or both of (112) (hex AlN 68.85?) and (201) (hex AlN 69.98?).
[0136] XRD analysis was also made on Sample 8 (comparative). Significant hexagonal peaks were seen.
EBSD:
[0137] Electron backscatter diffraction (EBSD) analysis was made on Sample 2a (invention) and Sample 6 (invention). A cumulative frequency distribution of 111 misorientation angles was calculated, as described in the Methods section.
[0138] For Sample 2a (invention) the (Ti,Al)N layer shows a cumulative frequency distribution of the 111 misorientation angles such that about 94% of the 111 misorientation angles are less than 10 degrees.
[0139]
[0140] For Sample 6 (invention) the (Ti,Al)N layer shows a cumulative frequency distribution of the 111 misorientation angles such that about 77% of the 111 misorientation angles are less than 10 degrees.
TEM:
[0141] Transmission electron microscope (TEM) analysis was made on Sample 2a (invention) The diffraction pattern from Sample 2a (invention) is seen in
[0142] TEM analysis on Sample 2a (invention) showed that the average thickness of each of the (Ti,Al)N sublayer types was about the same being about 3 nm.
EDX:
[0143] The average composition of the (Ti,Al)N layer of Sample 2a (invention) was proven to correspond to the expected values from target composition by Energy Dispersive X-Ray Spectroscopy (EDX) analysis. The average composition was Ti.sub.0.27Al.sub.0.73N, i.e., the (Ti,Al)N layer had an overall atomic ratio Al/(Ti+Al) of 0.73.
Grain Width:
[0144] The grain width was determined for Sample 2a (invention). The grain width was determined at distances from the lower interface to the substrate of 2, 4 and 6 ?m. The average grain width values were 127, 165 and 247 nm, respectively.
Example 7
Cutting Test, ISO-P Milling:
[0145] Sample 11 (invention) was further tested in an ISO-P milling test, and the flank wear was measured. In this test Sample 11 (invention) was compared with a cutting insert known to be good in ISO-P milling.
[0146] The comparative coated tool was made by providing milling insert cemented carbide substrates of geometry SPMW12, having a composition of 8 wt % Co and balance WC, and depositing a coating according to the conditions below:
Innermost Ti.sub.0.40Al.sub.0.60N layer:
TABLE-US-00008 Target material: Ti.sub.0.40Al.sub.0.60 Target size: 6 ? circular, diameter 15 cm Average power per target: 9 kW Peak pulse power: 55 kW Pulse on time: 4 ms Temperature: 430? C. Total pressure: 0.61 Pa Argon pressure: 0.43 Pa Bias potential: ?40 V
[0147] A layer of 2.1 ?m was deposited.
Outermost ZrN Layer:
[0148]
TABLE-US-00009 Target material: Zr Target size: 3 ? circular, diameter 15 cm Average power per target: 9 kW Peak pulse power: 27 kW Pulse on time: 26 ms Temperature: 430? C. Total pressure: 0.55 Pa Argon pressure: 0.43 Pa Bias potential: ?40 V
[0149] A layer of 0.2 ?m was deposited.
[0150] The comparative samples were ones from commercial production. It comprises an upper thin ZrN layer of 0.2 ?m deposited for the purpose of colour and easier wear detection. However, this additional layer does not influence the wear resistance in any substantial way.
[0151] The test conditions and test data are summarized below. As workpiece material steel (ISO-P) was used.
Test Conditions:
[0152] A milling test was performed at a cutting speed of 240 m/min. The other testing conditions are as follows:
Tool Geometry:
[0153]
TABLE-US-00010 Insert geometry: SPMW12 Tool diameter D.sub.c: 125 mm Setting angle ?: 45?
Cutting Data:
[0154]
TABLE-US-00011 Contact width a.sub.e: 100 mm Cutting depth a.sub.p: 3 mm Cutting speed: 240 m/min Feed per tooth: 0.2 mm
Workpiece:
[0155]
TABLE-US-00012 Material ISO-P steel, 42CrMoV4 type Tensile strength 785 MPa Cutting fluid: none, i.e. dry
[0156] In this test the wear maximum was observed at the cutting edge on the flank side. Three cutting edges were tested of each sample and the averaged value for each cutting length is shown in Table 2.
TABLE-US-00013 TABLE 2 Cutting length (mm) Sample 2000 3000 4000 4800 Sample 11 0.09 0.11 0.12 0.14 (invention) VB.sub.max [mm] Comparative 0.10 0.13 0.18 0.22 VB.sub.max [mm]
[0157] The comparative sample has a coating known to give very good results in milling of ISO-P steel. Nevertheless, it is concluded that Sample 10 (invention) performs much better than the comparative sample.
Example 8
Cutting Test, ISO-M Milling:
[0158] Sample 11 (invention) was further tested in an ISO-M milling test, and the flank wear was measured. In this test Sample 11 (invention) was compared with a cutting insert having an arc-deposited coating known to be good in ISO-M milling.
[0159] The comparative coated tool was made by providing milling insert cemented carbide substrates having a composition of 8 wt % Co and balance WC and depositing a coating according to the conditions below:
Innermost Multilayer Ti.sub.0.50Al.sub.0.50N/Ti.sub.0.33Al.sub.0.87N Layer:
TABLE-US-00014 Target material: 1 ? Ti.sub.0.50Al.sub.0.50/1 ? Ti.sub.0.33Al.sub.0.67 Temperature: 550? C. Total pressure: 10 Pa Bias potential: ?60 V
[0160] A layer of 1.3 ?m was deposited.
Outermost Multilayer Ti.sub.0.50Al.sub.0.50N/Ti.sub.0.33Al.sub.0.67N Layer:
TABLE-US-00015 Target material: 1 ? Ti.sub.0.50Al.sub.0.50/2 ? Ti.sub.0.33Al.sub.0.67 Temperature: 550? C. Total pressure: 10 Pa Bias potential: ?50 V
[0161] A layer of 1.2 ?m was deposited.
[0162] The test conditions and test data are summarized below. As workpiece material stainless steel (ISO-M) was used.
Test Conditions:
Tool Geometry:
[0163]
TABLE-US-00016 Insert geometry: ADMT160608R-F56 Tool diameter D.sub.c: 63 mm Setting angle ?: 90? Number of teeth/inserts mounted: 3
Cutting Data:
[0164]
TABLE-US-00017 Contact width a.sub.e: 50 mm Cutting depth a.sub.p: 3 mm Cutting speed: 240 m/min Feed per tooth: 0.15 mm
Workpiece:
[0165]
TABLE-US-00018 Material 1.4571/V4A-stainless steel Tensile strength 720 MPa Cutting fluid: none, i.e. dry
[0166] In this test the wear maximum was observed at the cutting edge on the flank side. Three cutting edges were tested of each coating and the averaged value for each cutting length is shown in Table 3.
TABLE-US-00019 TABLE 3 Cutting length (mm) Sample 1000 2000 3000 4000 5000 Sample 11 0.04 0.06 0.07 0.08 0.10 (invention) VB.sub.max [mm] Comparative 0.08 0.09 0.11 0.12 0.16 VB.sub.max [mm]
[0167] The comparative sample has a coating known to give very good results in milling of stainless steel (ISO-M). Nevertheless, it is concluded that Sample 11 (invention) performs much better than the comparative sample.