Cutting tool

Abstract

A cutting tool provided with a base material and a coating film provided on the base material, wherein the coating film includes a hard particle layer composed of a plurality of hard particles composed of titanium, silicon, carbon, and nitrogen, the hard particle layer includes a first region that is a region sandwiched by a first main surface of the base material side of the hard particle layer and an imaginary surface S1 of a distance of 0.5 μm from the first main surface toward the hard particle layer side, and a second region that is a region sandwiched by a second main surface of the opposite side of the first main surface of the hard particle layer and an imaginary surface S2 of a distance of 0.5 μm from the second main surface toward the hard particle layer side, the composition of the first region is Ti (1‑Xb) Si Xb CN, the composition of the second region is Ti (1‑Xs) Si Xs CN, the Xs and Xb satisfy the relations of Xs - Xb ≥ 0.01 and 0 < Xb < Xs ≤ 0.10, the hard particle is a cubic crystal structure, and in the hard particle, the concentration of the silicon periodically changes along a first direction from the first main surface toward the second main surface.

Description

Technical Field

[0001] This disclosure relates to cutting tools. Background Technology

[0002] In the past, in order to improve the wear resistance of cutting tools, cutting tools with TiSiCN films formed on the substrate have been developed (for example, Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: International Publication No. 2022 / 230363 Summary of the Invention

[0006] The cutting tool disclosed herein comprises a substrate and a coating disposed on said substrate, wherein,

[0007] The coating comprises a rigid granular layer.

[0008] The hard particle layer is composed of multiple hard particles, which are made of titanium, silicon, carbon, and nitrogen.

[0009] The hard particle layer includes a first region and a second region.

[0010] The first region is the region enclosed by a first main surface on the substrate side of the hard particle layer and an imaginary surface S1 at a distance of 0.5 μm from the first main surface on the hard particle layer side.

[0011] The second region is the region enclosed by the second main surface of the hard particle layer opposite to the first main surface and an imaginary surface S2 located 0.5 μm away from the second main surface on the side of the hard particle layer.

[0012] The first region is composed of Ti (1-Xb) Si Xb CN

[0013] The second region is composed of Ti (1-Xs) Si Xs CN

[0014] The Xs and Xb satisfy the relationships Xs-Xb≥0.01 and 0<Xb<Xs≤0.10.

[0015] The hard particles have a cubic crystal structure.

[0016] In the hard particles, the concentration of silicon varies periodically along a first direction from the first main surface toward the second main surface. Attached Figure Description

[0017] Figure 1 This is a schematic diagram showing an example of a cross-section of the cutting tool according to Embodiment 1.

[0018] Figure 2 This is a schematic diagram showing another example of a cross-section of the cutting tool involved in Embodiment 1.

[0019] Figure 3 This is a schematic diagram showing another example of a cross-section of the cutting tool involved in Embodiment 1.

[0020] Figure 4 This is a schematic diagram showing another example of a cross-section of the cutting tool involved in Embodiment 1.

[0021] Figure 5 This is a schematic diagram showing another example of a cross-section of the cutting tool involved in Embodiment 1.

[0022] Figure 6 This is a schematic cross-sectional view of an example of a CVD apparatus used in the manufacture of the cutting tool according to Embodiment 2. Detailed Implementation

[0023] [The problem this disclosure aims to solve]

[0024] The cutting tool of Patent Document 1 exhibits excellent wear resistance due to its high-hardness TiSiCN film. However, when using the cutting tool of Patent Document 1 to cut materials with high cutting resistance, such as FCD700 (ductile iron), the tool life may be reached due to the deterioration of the coating. Therefore, there is a need for a cutting tool that can maintain a long tool life, especially when cutting materials with high cutting resistance.

[0025] Therefore, the purpose of this disclosure is to provide a cutting tool that can have a long tool life, especially when cutting workpieces with high cutting resistance.

[0026] [The Effects of This Disclosure]

[0027] According to this disclosure, a cutting tool with a long tool life can be provided, especially when cutting workpieces with high cutting resistance.

[0028] [Description of embodiments of this disclosure]

[0029] First, embodiments of this disclosure will be described.

[0030] (1) The cutting tool of this disclosure comprises a substrate and a coating disposed on said substrate, wherein,

[0031] The coating comprises a rigid granular layer.

[0032] The hard particle layer is composed of multiple hard particles, which are made of titanium, silicon, carbon, and nitrogen.

[0033] The hard particle layer includes a first region and a second region.

[0034] The first region is the region enclosed by a first main surface on the substrate side of the hard particle layer and an imaginary surface S1 at a distance of 0.5 μm from the first main surface on the hard particle layer side.

[0035] The second region is the region enclosed by the second main surface of the hard particle layer opposite to the first main surface and an imaginary surface S2 located 0.5 μm away from the second main surface on the side of the hard particle layer.

[0036] The first region is composed of Ti (1-Xb) Si Xb CN

[0037] The second region is composed of Ti (1-Xs) Si Xs CN

[0038] The Xs and Xb satisfy the relationships Xs-Xb≥0.01 and 0<Xb<Xs≤0.10.

[0039] The hard particles have a cubic crystal structure.

[0040] In the hard particles, the concentration of silicon varies periodically along a first direction from the first main surface toward the second main surface.

[0041] According to this disclosure, a cutting tool with a long tool life can be provided, especially when cutting workpieces with high cutting resistance.

[0042] (2) Alternatively, in (1) above, the hard particle layer has a columnar structure. Therefore, the hard particle layer experiences stronger stress relative to the shear direction, resulting in improved wear resistance. Furthermore, since the hard particle layer has fewer grain boundaries in the direction perpendicular to the film thickness, the number of potential failure points is reduced, further improving its resistance to defects.

[0043] (3) Alternatively, in (1) or (2) above, the ratio L1 / T1 of the length L1 of the hard particles along the first direction to the thickness T1 of the hard particle layer is 0.3 or more. This results in stronger stress in the hard particle layer relative to the shear direction, improving wear resistance. Furthermore, since the hard particle layer has fewer grain boundaries in the direction perpendicular to the film thickness, there are fewer initiation points for damage, thus improving resistance to defects.

[0044] (4) Alternatively, in any of (1) to (3) above, the period width of the concentration of silicon in the hard particles along the first direction is 3 nm or more and 20 nm or less. This maintains the strain within the hard particles, further suppressing the progression of cracking in the coating, and further improving the chip resistance of the cutting tool.

[0045] (5) Alternatively, in any of (1) to (4) above, the average thickness of the hard particle layer is 2 μm or more and 15 μm or less. As a result, the tool life is further improved.

[0046] (6) could also be any one of (1) to (5) above,

[0047] The coating includes a base layer disposed between the substrate and the rigid particle layer.

[0048] The substrate layer comprises at least one selected from the group consisting of TiN layer, TiC layer, TiCN layer, TiBN layer, TiCNO layer and Al2O3 layer.

[0049] By configuring TiN, TiC, TiCN, TiCNO, or TiBN layers as the base layer, the adhesion between the substrate and the coating can be improved. Additionally, using an Al2O3 layer as the base layer can enhance the oxidation resistance of the coating.

[0050] (7) could also be any one of (1) to (6) above,

[0051] The coating includes a surface layer disposed on the outermost surface of the coating.

[0052] The surface layer is a TiN layer or an Al2O3 layer.

[0053] As a result, the coating's resistance to heat cracking and its abrasion resistance are improved.

[0054] [Details of the embodiments disclosed herein]

[0055] In this disclosure, expressions such as "A~B" refer to the upper and lower limits of a range (i.e., above A and below B). When there is no unit recorded in A but only in B, the unit of A is the same as the unit of B.

[0056] In this disclosure, when compounds are represented by chemical formulas, all previously known atomic ratios are included without specifically limiting the atomic ratios, and are not necessarily limited to atomic ratios within the stoichiometric range.

[0057] In this disclosure, when more than one value is recorded as both the lower and upper limits of a numerical range, combinations of any value recorded in the lower limit and any value recorded in the upper limit are also disclosed. For example, when a1 or higher, b1 or higher, and c1 or higher are recorded as the lower limit, and a2 or lower, b2 or lower, and c2 or lower are recorded as the upper limit, the following combinations are disclosed: a1 or higher and a2 or lower, a1 or higher and b2 or lower, a1 or higher and c2 or lower, b1 or higher and a2 or lower, b1 or higher and b2 or lower, b1 or higher and c2 or lower, c1 or higher and a2 or lower, c1 or higher and b2 or lower, and c1 or higher and c2 or lower.

[0058] The inventors of this invention, while developing a cutting tool that can have a long tool life even when cutting materials with high cutting resistance, used conventional cutting tools to cut materials with high cutting resistance and observed the damage morphology of the coating.

[0059] When cutting materials with high cutting resistance using the cutting tool described in Patent Document 1, the following situation was observed: On the rake face where the chips pass, the load in the shear direction is large, and the area near the substrate becomes a fulcrum, causing cracking, which exacerbates the film damage. It is speculated that this is because the TiSiCN film has high hardness and therefore excellent wear resistance, but its toughness is insufficient for cutting materials with high cutting resistance.

[0060] Based on the above-mentioned insights, the inventors of this invention conducted in-depth research and obtained a cutting tool that can maintain a long tool life even when cutting materials with high cutting resistance. Specific examples of the cutting tool of this disclosure will now be described with reference to the accompanying drawings. In the drawings of this disclosure, the same reference numerals denote the same or equivalent parts. Furthermore, dimensional relationships such as length, width, thickness, and depth have been appropriately modified for clarity and simplification of the drawings and do not necessarily represent actual dimensional relationships.

[0061] [Implementation Method 1: Cutting Tool]

[0062] use Figures 1-5 A cutting tool according to one embodiment of the present disclosure (hereinafter also referred to as "this embodiment") will be described.

[0063] The cutting tool 1 of this embodiment includes a substrate 10 and a coating 15 disposed on the substrate 10, wherein,

[0064] The coating 15 includes a hard particle layer 11.

[0065] The hard particle layer 11 is composed of multiple hard particles, which are made of titanium, silicon, carbon, and nitrogen.

[0066] The hard particle layer 11 includes a first region A1 and a second region A2.

[0067] The first region A1 is the region enclosed by the first main surface Q1 on the substrate 10 side of the hard particle layer 11 and the imaginary surface S1 at a distance of 0.5 μm from the first main surface Q1 toward the hard particle layer 11 side.

[0068] The second region A2 is the region enclosed by the second main surface Q2 of the hard particle layer 11, which is opposite to the first main surface Q1, and an imaginary surface S2, which is 0.5 μm away from the second main surface Q2 toward the hard particle layer 11.

[0069] The first region A1 is composed of Ti (1-Xb) Si Xb CN

[0070] The second region A2 is composed of Ti (1-Xs) Si Xs CN

[0071] Xs and Xb satisfy the relationships Xs-Xb≥0.01 and 0<Xb<Xs≤0.10.

[0072] The hard particles have a cubic crystal structure.

[0073] In hard particles, the concentration of silicon varies periodically along a first direction from the first principal surface toward the second principal surface.

[0074] The cutting tool of this embodiment can have a long tool life even when cutting materials with high cutting resistance. The reason is not yet clear, but it is speculated to be as follows (i) to (iii).

[0075] (i) In the cutting tool of this embodiment, the coating has a hard particle layer composed of multiple hard particles made of titanium, silicon, carbon, and nitrogen. The hard particle layer has high hardness. Therefore, the cutting tool with the hard particle layer has excellent wear resistance. Thus, the cutting tool can have a long tool life.

[0076] (ii) In the cutting tool of this embodiment, the hard particle layer includes a first region on the substrate side and a second region on the surface side. The silicon content of the first region is lower than that of the second region, and the toughness of the first region is better than that of the second region. Therefore, the cutting tool with the hard particle layer can suppress the generation of cracks centered on the position of the hard particle layer near the substrate when cutting materials with high cutting resistance. Therefore, the cutting tool can have a longer tool life.

[0077] (iii) In the hard particles of the cutting tool of this embodiment, the silicon concentration varies periodically along a first direction from the first main surface of the hard particle layer toward the second main surface. Therefore, even if strain occurs within the hard particles, causing cracks associated with cutting to form on the surface of the coating, the propagation of these cracks into the substrate can be effectively suppressed. Furthermore, the increased hardness of the hard particles and the hard particle layer improves the wear resistance of the cutting tool. Thus, the cutting tool can have a longer tool life.

[0078] <Cutting Tools>

[0079] like Figure 1 As shown, the cutting tool 1 of this embodiment includes a substrate 10 and a coating 15 disposed on the substrate 10. Figure 1 This indicates that the coating 15 consists solely of the hard particle layer 11. The coating 15 preferably covers at least a portion of the cutting area of ​​the substrate, more preferably the entire surface of the substrate. The cutting area of ​​the substrate refers to the region on the substrate surface within 500 μm of the blade tip edge. Even if a portion of the substrate is not covered by the coating or the composition of the coating differs locally, this does not depart from the scope of this disclosure.

[0080] Types of Cutting Tools

[0081] The cutting tools disclosed herein may be, for example, drill bits, end mills (e.g., ball end mills), indexable cutting inserts for drill bits, indexable cutting inserts for end mills, indexable cutting inserts for milling, indexable cutting inserts for turning, metalworking saws, gear cutting tools, reamers, taps, etc.

[0082] <Substrate>

[0083] The substrate 10 includes a rake face and a flank face. Any conventionally known substrate can be used as such a substrate. For example, it is preferably a cemented carbide (e.g., a WC-based cemented carbide containing tungsten carbide and cobalt, which may contain carbonitrides of Ti, Ta, Nb, etc.), a cermet (a cermet mainly composed of TiC, TiN, TiCN, etc.), a high-speed steel, a ceramic (titanium carbide, silicon carbide, silicon nitride, aluminum nitride, alumina, etc.), a cubic boron nitride sintered body, or a diamond sintered body.

[0084] The substrate is composed of a cemented carbide containing tungsten carbide and cobalt, wherein the cobalt content in the cemented carbide can be 5% by mass or more and 11% by mass or less. This results in an excellent balance between hardness and strength at high temperatures, giving the substrate excellent properties for cutting tools used in the aforementioned applications. When using a WC-based cemented carbide as the substrate, its microstructure may include free carbon and an anomalous layer referred to as the η phase or ε phase.

[0085] Furthermore, the surface of the substrate can be modified. For example, in the case of cemented carbide, a de-β layer can be formed on its surface, and in the case of cermet, a surface-hardened layer can be formed. The substrate exhibits the desired effect even after its surface has been modified.

[0086] When the cutting tool is an indexable cutting insert, the substrate may or may not have a chip breaker. The shape of the tool tip edge can be any of the following: a sharp edge (the edge where the rake face and flank face intersect), honing (giving the sharp edge a rounded corner), a negative cutting edge (beveling), or a combination of honing and a negative cutting edge.

[0087] <Lamination>

[0088] The Composition of Coating

[0089] The coating in this embodiment includes a hard particle layer. The coating in this embodiment only needs to include a hard particle layer, but it may also include other layers.

[0090] For example, such as Figure 2 As shown in the cutting tool 1, the coating 15 may also include a base layer 12 disposed between the substrate 10 and the hard particle layer 11, based on the hard particle layer 11.

[0091] like Figure 3 As shown in the cutting tool 1, the coating 15 may also include a surface layer 13 disposed on the hard particle layer 11, in addition to the hard particle layer 11 and the base layer 12.

[0092] like Figure 4 As shown in the cutting tool 1, the coating 15 may also include an intermediate layer 14 disposed between the base layer 12 and the hard particle layer 11, in addition to the hard particle layer 11, the base layer 12, and the surface layer 13.

[0093] Details about the hard particle layer, base layer, intermediate layer, and surface layer will be described later.

[0094] The thickness of the coating

[0095] The thickness of the coating in this embodiment can be 2 μm or more and 30 μm or less. Here, the coating thickness refers to the overall thickness of the coating. If the overall thickness of the coating is 3 μm or more, it can exhibit excellent wear resistance. On the other hand, if the overall thickness of the coating is 30 μm or less, peeling or damage to the coating when significant stress is applied between the coating and the substrate can be suppressed during machining. From the viewpoint of improving wear resistance, the lower limit of the overall thickness of the coating can be 2 μm or more, or 5 μm or more, or 8 μm or more, or 10 μm or more. From the viewpoint of suppressing peeling or damage to the coating, the upper limit of the overall thickness of the coating can be 30 μm or less, or 25 μm or less, or 20 μm or less. The overall thickness of the coating can be 5 μm or more and 25 μm or less, or 8 μm or more and 20 μm or less.

[0096] In this disclosure, the thickness of the coating is measured according to the following steps: A cutting tool is used to cut a section parallel to the normal direction of the surface to obtain a test sample exposing the cross-section of the coating. The thickness of the coating is measured by observing the test sample using a scanning transmission electron microscope (STEM). The test sample is a thin sheet sample processed using an ion slicer or the like. An example of a scanning transmission electron microscope is the JEM-2100F (trademark) manufactured by Nippon Electron Ltd. The measurement conditions are set to an accelerating voltage of 200 kV and a current of 0.3 nA.

[0097] In this disclosure, the term "thickness" refers to the average thickness. Specifically, the magnification of the specimen for measurement is set to 10,000x, and a rectangular field of view is set in the electron microscope image, which is 100 μm long parallel to the surface of the cutting tool × the length of the entire thickness including the coating. The thickness range of ten locations is measured in this field of view, and the average value is set as "thickness". The thickness (average thickness) of each layer described below is also measured and calculated in the same way.

[0098] The following has been confirmed: as long as the measurement is performed on the same sample, even if the selected location of the measurement field is changed and multiple measurements are performed, the measurement results will have almost no deviation. Even if the measurement field is set arbitrarily, the results will not change arbitrarily.

[0099] <Hard granular layer>

[0100] Composition of Hard Granular Layers

[0101] The hard particle layer of this embodiment is composed of multiple hard particles, which are composed of titanium, silicon, carbon, and nitrogen. The hard particle layer can also be described as a TiSiCN layer composed of hard particles made of TiSiCN. The TiSiCN layer has high hardness. Therefore, cutting tools with a TiSiCN layer exhibit excellent wear resistance. Without impairing the effects of this disclosure, the hard particle layer may also contain impurity elements in addition to titanium, silicon, carbon, and nitrogen. Examples of impurity elements include chlorine, cobalt, tungsten, and oxygen. The content of impurity elements in the hard particle layer can, for example, be set to 0.5 atomic percent or less. The content of impurity elements in the hard particle layer is determined by EDX (Energy Dispersive X-ray Spectroscopy) with TEM (Transmission Electron Microscopy): TEM-EDX.

[0102] like Figure 5 As shown, the hard particle layer 11 includes a first region A1 and a second region A2. The first region A1 is the region sandwiched between a first main surface Q1 on the substrate 10 side of the hard particle layer 11 and an imaginary surface S1 extending 0.5 μm from the first main surface Q1 toward the hard particle layer 11 side. The second region A2 is the region sandwiched between a second main surface Q2 on the side of the hard particle layer 11 opposite to the first main surface Q1 and an imaginary surface S2 extending 0.5 μm from the second main surface Q2 toward the hard particle layer side.

[0103] The first region is composed of Ti (1-Xb) Si Xb CN, the second region is composed of Ti (1-Xs) Si Xs CN. Among them, Xs and Xb satisfy the relationships Xs-Xb≥0.01 and 0<Xb<Xs≤0.10.

[0104] The lower limit of Xs-Xb can be above 0.01, or above 0.02, or above 0.03, or above 0.04. The upper limit of Xs-Xb can be below 0.09, below 0.08, or below 0.07. Xs-Xb can be above 0.01 and below 0.09, above 0.02 and below 0.08, above 0.03 and below 0.07, or above 0.04 and below 0.07.

[0105] The lower limit of Xb can be above 0.01, above 0.02, or above 0.03. The upper limit of Xb can be below 0.09, below 0.08, or below 0.07. Xb can be above 0.01 and below 0.09, above 0.02 and below 0.08, or above 0.03 and below 0.07.

[0106] The lower limit of Xs can be above 0.02, above 0.03, or above 0.04. The upper limit of Xs can be below 0.10, below 0.09, or below 0.08. Xs can be above 0.02 and below 0.10, above 0.03 and below 0.09, or above 0.04 and below 0.08.

[0107] In this disclosure, the first region consists of Ti (1-Xb) Si Xb CN and the composition of the second region Ti (1-Xs) Si Xs CN is determined according to the following steps.

[0108] (A1) Using a diamond wire cutter along the normal to the surface of the cutting tool, the profile of the hard granular layer is exposed. The exposed profile is then subjected to focused ion beam machining (hereinafter also referred to as "FIB machining") to achieve a mirror finish.

[0109] (A2) In the cross-section after FIB processing, the composition was determined by line analysis using EDX (SEM-EDX) with an attached SEM (Scanning Electron Microscopy) along the thickness direction of the coating. The beam diameter for line analysis was less than 0.9 nm, the scanning interval was 50 nm, and the accelerating voltage was 15 kV. The results of the line analysis removed chlorine, tungsten, cobalt, and oxygen as impurity elements, identifying region A as composed of titanium, silicon, carbon, and nitrogen. In the above cross-section, region A was identified in three non-overlapping locations separated by more than 1 μm. In the above cross-section, the line connecting the closest points of region A to the substrate in each of the three locations corresponds to the first principal surface Q1 on the substrate side of the hard particle layer. In the above cross-section, the line connecting the furthest points of region A to the substrate in each of the three locations corresponds to the second principal surface Q2 on the side of the hard particle layer opposite to the first principal surface Q1. In the above cross-section, the region sandwiched between the first principal surface Q1 and the second principal surface Q2 corresponds to the hard particle layer 11.

[0110] (A3) In the cross-section after FIB processing, a first region and a second region are defined within the hard particle layer. The first region A1 is the region sandwiched between a first main surface Q1 on the substrate 10 side of the hard particle layer 11 and an imaginary surface S1 at a distance of 0.5 μm from the first main surface Q1 toward the hard particle layer 11 side. The second region A2 is the region sandwiched between a second main surface Q2 on the side of the hard particle layer 11 opposite to the first main surface Q1 and an imaginary surface S2 at a distance of 0.5 μm from the second main surface Q2 toward the hard particle layer 11 side.

[0111] (A4) In the first region A1, rectangular analysis is performed using SEM-EDX to determine the composition of the first region A1. The rectangular analysis is performed on 0.5 μm × 2 μm rectangular measurement areas defined at three non-overlapping locations within the first region A1. In this disclosure, the average composition of the three measurement areas corresponds to the composition Ti of the first region A1. (1-Xb) Si Xb CN. Through the steps described above, Xb can be obtained.

[0112] Within the second region A2, rectangular analysis was performed using SEM-EDX to determine the composition of region A2. The rectangular analysis was performed on 0.5 μm × 2 μm rectangular measurement areas defined at three non-overlapping locations within the second region A2. In this disclosure, the average composition of the three measurement areas corresponds to the composition Ti of the second region. (1-Xs) Si Xs CN. Through the steps described above, Xs can be obtained.

[0113] The following was confirmed: as long as the measurement is performed on the same sample, even if the cutting position of the cutting tool and the measurement area are changed and multiple measurements are performed, the measurement results are almost without deviation.

[0114] The hard granular layer of this embodiment may also include a third region sandwiched between the first and second regions. The composition of the third region is not particularly limited, as long as it does not impair the effects of this disclosure. The composition of the third region can be one that maintains the continuity of the structure of the hard granular layer. In the composition of the third phase Ti... (1-Xm) Si Xm In CN, it was confirmed that if Xb×0.9<Xm<Xs×1.1, the effect of this disclosure is not impaired. The composition of the third region is determined by the same method as the method for determining the composition of the first region described above.

[0115] Crystal Structure of Hard Particles

[0116] In this embodiment, the hard particles have a cubic crystalline structure. Having a cubic crystalline structure allows for a balance between excellent wear resistance and high toughness. This cubic crystalline structure of the hard particles can be confirmed through pattern analysis based on limited field-of-view electron diffraction.

[0117] Changes in silicon concentration in hard particles

[0118] In the hard particles of this embodiment, the silicon concentration varies periodically along a first direction from the first principal surface of the hard particle layer toward the second principal surface. This periodic variation of silicon concentration along the first direction from the first principal surface of the hard particle layer toward the second principal surface can be confirmed through the following steps.

[0119] (B1) Using a diamond wire cutter along the normal to the surface of the cutting tool, the profile of the hard granular layer is exposed. The exposed profile is then subjected to focused ion beam machining (hereinafter also referred to as "FIB machining") to achieve a mirror finish.

[0120] (B2) The cross-section after FIB processing was observed using bright-field scanning electron microscopy (BF-SEM) to identify a hard particle. Then, a BE-STEM image of the identified hard particle was obtained.

[0121] (B3) In the BF-STEM image above, the measurement area (size: 100nm × 100nm) is set up such that there are 10 or more layers of the white layer and the black layer respectively. The black layer is the area with a high silicon content, and the white layer is the area with a low silicon content.

[0122] (B4) Within the measurement area of ​​the BF-STEM image described above, the stacking orientation of the layer represented by white (hereinafter also referred to as "white layer") and the layer represented by black (hereinafter also referred to as "black layer") is determined. Specifically, the electron beam diffraction pattern limiting the field of view is overlapped with the stacking orientation of the white layer and the black layer, and the stacking orientation is determined based on the orientation shown by the diffraction spots.

[0123] (B5) In the measurement area of ​​the above BF-STEM image, along the stacking direction, line analysis was performed using EDX (Energy Dispersive X-ray Spectroscopy) with attached STEM to determine the composition. The beam diameter for line analysis was less than 0.5 nm, the scanning interval was 0.5 nm, and the length of the line analysis was 50 nm.

[0124] (B6) Construct a graph to display the results of the line analysis on a coordinate system, in which the X-axis represents the distance from the starting point of the measurement, and the Y-axis represents the number of silicon atoms A.Si Relative to the number of atoms A of titanium Ti With the number of atoms A of silicon Si The total percentage {A} Si / (A Ti +A Si )}×100. In this chart, calculate {A} in the measurement area. Si / (A Ti +A Si The average of {A} × 100 (hereinafter also referred to as "average"). As the distance from the starting point of the measurement increases, compared to this average, in {A}... Si / (A Ti +A Si )} large area and {A Si / (A Ti +A Si In the case of alternating small regions, it was confirmed that the concentration of silicon in the hard particles periodically changes along a first direction from the first principal surface of the hard particle layer toward the second principal surface.

[0125] It was confirmed that as long as the measurement is performed on the same sample, even if the hard particles determined by (B2) above are changed and multiple measurements are performed, the measurement results are almost unbiased.

[0126] Period width of silicon concentration in hard particles

[0127] In the hard particles of this embodiment, the period width of the silicon concentration along a first direction from the first main surface of the hard particle layer to the second main surface can be 3 nm or more and 20 nm or less. This maintains the strain within the hard particles, further suppressing crack propagation in the coating and further improving the chip resistance of the cutting tool. The period width of the silicon concentration can be 3 nm or more and 15 nm or less, or it can be 5 nm or more and 10 nm or less.

[0128] In this disclosure, the method for determining the period width of silicon concentration is as follows. A measurement region is set using the same method as described in (B1) to (B3) above. A Fourier transform is performed on the measurement region to obtain a Fourier transform image. In the Fourier transform image, the periodicity within the measurement region is represented by points. The period width is calculated by calculating the reciprocal of the distance between the points and the center of the image representing the maximum intensity in the Fourier transform image.

[0129] The following has been confirmed: as long as the measurement is performed on the same sample, even if the measurement site is changed and multiple measurements are performed, the measurement results are almost without deviation.

[0130] Tissue of the hard granular layer

[0131] The hard particle layer in this embodiment can be a columnar structure. Therefore, the hard particle layer exhibits stronger stress relative to the shear direction, resulting in improved wear resistance. Furthermore, since the hard particle layer has fewer grain boundaries in the direction perpendicular to the film thickness, the number of potential failure points is reduced, further improving resistance to defects.

[0132] In this disclosure, a columnar structure of the hard particle layer means that the percentage (N1) of the number of first hard particles with an aspect ratio of 3 or more relative to the total number N of all hard particles constituting the hard particle layer (N1 / N) × 100 is 50% or more. Specifically, this columnar structure of the hard particle layer is confirmed through the following steps.

[0133] (C1) Using a diamond wire cutter along the normal to the surface of the cutting tool, the profile of the hard granular layer is exposed. The exposed profile is then subjected to focused ion beam machining (hereinafter also referred to as "FIB machining") to achieve a mirror finish.

[0134] (C2) Using a field emission scanning electron microscope (FE-SEM) equipped with an electron backscatter diffraction (EBSD) device (product name: "SUPRA35VP", manufactured by Carl Zeiss), EBSD analysis was performed on the FIB-processed cross-section under the following measurement conditions. The area for EBSD analysis (hereinafter also referred to as the analysis area) is a rectangular area consisting of three non-overlapping locations within the hard particle layer. The size of the analysis area is a rectangle with a length of 20 μm or more in the direction parallel to the substrate. The length of the analysis area in the thickness direction of the coating can be appropriately set according to the thickness of the hard particle layer. The length of the analysis area in the thickness direction of the coating is set to, for example, 90% or more of the thickness of the hard particle layer.

[0135] (Measurement conditions)

[0136] Accelerating voltage: 15kV

[0137] Current value: 1.8nA

[0138] Irradiation current: 60μm (with HC)

[0139] Exp: Long 0.03s

[0140] Binning: 8×8

[0141] WD: 15mm

[0142] Tilt: 70°

[0143] Step size: 0.02μm

[0144] BKD: Background Subtraction

[0145] Dynamic Background Subtraction

[0146] Normalized Intensity Histogram

[0147] Magnification: 20000x

[0148] Grain boundary definition: 15° or higher

[0149] (C3) For data collected through EBSD parsing, only data satisfying CI > 0.1 is identified using the CIDilation (single Interaction) and Grain CI Standardization methods, and then cleaned up. The CI value is calculated using the Voting method. Specifically, it is calculated as CI = (V1 - V2) / Video (V1, V2: the first and second solutions, Video: the ideal solution).

[0150] (C4) The EBSD analysis results were analyzed using commercially available software (product name: "OIM7.1", manufactured by TSL Solutions Co., Ltd.), and an Inverse Pole Tigre map (IPF map) of the analyzed region was generated. In generating this IPF map, a grain boundary was defined as a difference in orientation angle of 15° or more between adjacent measurement points. The shape of each grain is shown in the IPF map, and the orientation of each grain is indicated by color differentiation.

[0151] (C5) Using the aforementioned software (“OMI7.1”), the aspect ratio of all hard particles within the IPF map of each analytical region is determined. The aspect ratio of a hard particle is the ratio of its major diameter a to its minor diameter b, b / a. In this disclosure, major diameter a is the maximum span diameter of the hard particle observed in the aforementioned cross-section, and minor diameter b is the maximum diameter of the hard particle along a direction orthogonal to major diameter a. In this disclosure, hard particles within the IPF map of the analytical region include both all hard particles present in the IPF map of the analytical region and at least a portion of hard particles present in the IPF map of the analytical region.

[0152] (C6) Calculate the percentage (n1 / n) × 100 of the number of first hard particles with an aspect ratio of 3 or greater relative to the total number of hard particles n in the IPF diagram of each analytical region. In this disclosure, the average of the percentage (n1 / n) × 100 in the IPF diagrams of the three analytical regions corresponds to the percentage (N1 / N) × 100 of the number of first hard particles with an aspect ratio of 3 or greater relative to the total number of hard particles N constituting the hard particle layer. When the percentage (N1 / N) × 100 is 50% or greater, the hard particle layer is confirmed to have a columnar structure.

[0153] The following was confirmed: as long as the measurement is performed on the same sample, even if the cutting position of the cutting tool and the measurement area are changed and multiple measurements are performed, the measurement results are almost without deviation.

[0154] In the hard particle layer of this embodiment, the lower limit of the percentage (N1 / N)×100 can be 60% or more, 70% or more, 80% or more, or 90% or more. The upper limit of the percentage (N1 / N)×100 can be, for example, 100% or less. The percentage (N1 / N)×100 can also be 60% or more and 100% or less, 70% or more and 100% or less, 80% or more and 100% or less, or 90% or more and 100% or less.

[0155] In this embodiment, the ratio L / T of the length L of the hard particles along the first direction to the thickness T of the hard particle layer can be 0.3 or more. This results in stronger stress in the hard particle layer relative to the shear direction, improving wear resistance. Furthermore, since the hard particle layer has fewer grain boundaries in the direction perpendicular to the film thickness, there are fewer initiation points for damage, further improving resistance to defects.

[0156] In this embodiment, from the viewpoint of improving wear resistance and damage resistance, the lower limit of the ratio L / T can be 0.4 or more, 0.5 or more, or 0.6 or more. The upper limit of the ratio L / T can be 1.0 or less, or 0.9 or less. The lower limit of the ratio L / T can be 0.3 or more and 1.0 or less, 0.4 or more and 1.0 or less, 0.5 or more and 0.9 or less, or 0.6 or more and 0.9 or less.

[0157] In this disclosure, the thickness T of the hard particle layer and the length L of the hard particles along the first direction are measured according to the following steps.

[0158] (D1) Following the same steps (C1) to (C4) as in the method for confirming that the hard particle layer has a columnar structure, an IPF map of the analytical region is prepared. In this step, the analytical region in (C1) is a rectangular area of ​​three non-overlapping locations, with a length of 100 μm parallel to the surface of the cutting tool and a length including the overall thickness of the coating.

[0159] (D2) Using software (“OMI7.1”), the thickness amplitude of ten locations is measured in the IPF plot of each analytical region along a first direction from the first principal plane of the hard particle layer to the second principal plane, and the average value t is calculated. The first direction is perpendicular to the first principal plane of the hard particle layer. In this disclosure, the average of the average value t of the three analytical regions corresponds to the thickness T of the hard particle layer.

[0160] (D3) Using software (“OMI7.1”), the length along the first direction of all hard particles within the IPF map of each resolution region is measured, and their average value L1 is calculated. In this disclosure, hard particles within the IPF map of the resolution region include both all hard particles present in the IPF map of the resolution region and hard particles with at least a portion present in the measurement region. In this disclosure, the average of the average value L1 of the resolution regions at the three locations corresponds to the length L of the hard particles along the first direction.

[0161] The following was confirmed: as long as the measurement is performed on the same sample, even if the cutting position of the cutting tool and the measurement area are changed and multiple measurements are performed, the measurement results are almost without deviation.

[0162] Thickness of the hard particle layer

[0163] In this embodiment, the thickness of the hard particle layer can be 2 μm or more and 15 μm or less. If the thickness of the hard particle layer is 2 μm or more, it exhibits excellent wear resistance. On the other hand, if the thickness of the hard particle layer is 15 μm or less, peeling or damage to the coating when significant stress is applied between the coating and the substrate can be suppressed during machining. From the viewpoint of improving wear resistance, the lower limit of the thickness of the hard particle layer can be 4 μm or more, or 6 μm or more, or 8 μm or more. From the viewpoint of suppressing peeling or damage to the coating, the upper limit of the thickness of the hard particle layer can be 15 μm or less, or 10 μm or less. The thickness of the hard particle layer can be 4 μm or more and 15 μm or less, or 6 μm or more and 10 μm or less.

[0164] <Basal layer>

[0165] The coating of embodiment 1 may include a base layer disposed between the substrate and the hard particle layer. The base layer may include at least one selected from the group consisting of TiN layer, TiC layer, TiCN layer, TiBN layer, TiCNO layer and Al2O3 layer.

[0166] As a base layer, the adhesion between the substrate and the coating can be improved by placing a TiN layer, TiC layer, TiCN layer, TiCNO layer, or TiBN layer immediately above the substrate. Using an Al2O3 layer as the base layer can improve the oxidation resistance of the coating. The average thickness of the base layer can be 0.1 μm or more and 20 μm or less. Therefore, the coating exhibits excellent wear resistance and damage resistance.

[0167] <Surface Layer>

[0168] The coating in Embodiment 1 may include a surface layer disposed on the outermost surface of the coating. The surface layer may be a TiN layer or an Al2O3 layer. The TiN layer has a clear color (golden), and therefore, if used as a surface layer, it has the advantage of easy identification of the corners of the cutting blade after cutting (identification of the used parts). By using an Al2O3 layer as the surface layer, the oxidation resistance of the coating can be improved.

[0169] The average thickness of the surface layer can be greater than 0.5 μm and less than 10 μm. This improves the adhesion between the surface layer and adjacent layers.

[0170] <Intermediate Layer>

[0171] The coating in Embodiment 1 may include an intermediate layer disposed between the substrate layer and the hard particle layer. When the substrate layer is a TiN layer, the intermediate layer is preferably a TiCN layer. Since the TiCN layer exhibits excellent wear resistance, appropriate wear resistance can be imparted through the coating. The average thickness of the intermediate layer can be 1 μm or more and 20 μm or less.

[0172] [Implementation Method 2: Method for Manufacturing a Cutting Tool]

[0173] An example of a method for manufacturing a cutting tool according to Embodiment 1 will be described. The method for manufacturing a cutting tool according to Embodiment 1 may include a first step of preparing a substrate and a second step of forming a coating on the substrate to obtain the cutting tool.

[0174] <First Process>

[0175] In the first step, a substrate is prepared. Details of the substrate are described in Embodiment 1, and therefore will not be repeated.

[0176] <Second Process>

[0177] Next, in the second process, a coating is formed on the substrate to obtain the cutting tool. The coating is formed, for example, using... Figure 6 The CVD apparatus shown is used for this process. Within the CVD apparatus 50, multiple substrate mounting fixtures 52 holding substrates 10 are installed, and these fixtures are covered by a reaction vessel 53 made of a heat-resistant alloy. Furthermore, a temperature control device 54 is arranged around the reaction vessel 53, allowing for temperature control within the reaction vessel 53.

[0178] The CVD apparatus 50 is equipped with a nozzle 56 having three inlet ports 55, 57 (another inlet port is not shown). The nozzle 56 is arranged to pass through the area where the substrate setting fixture 52 is located. A plurality of spray holes (first spray hole 61, second spray hole 62, and third spray hole (not shown)) are formed in the portion of the nozzle 56 near the substrate setting fixture 52.

[0179] exist Figure 6 In this process, the gases introduced into the nozzle 56 from inlet 55, inlet 57, and another inlet (not shown) do not mix within the nozzle 56, but are instead introduced into the reaction vessel 53 through different injection holes. The nozzle 56 is capable of rotating around its axis. Furthermore, the CVD apparatus 50 is equipped with an exhaust pipe 59, from which exhaust gases are discharged to the outside through exhaust port 60. Additionally, the fixtures and other components within the reaction vessel 53 are typically made of graphite.

[0180] When the coating comprises at least one of a base layer, an intermediate layer, and a surface layer, these layers can be formed by methods known in the art.

[0181] TiCl4, SiCl4, and CH3CN are used as feed gases. TiCl4 is ejected from a plurality of first injection holes provided in the nozzle, SiCl4 is ejected from a plurality of second injection holes provided in the nozzle, and CH3CN is ejected from a plurality of third injection holes provided in the nozzle. Specifically, TiCl4 is introduced into the nozzle 56 through the nozzle inlet 55 and ejected from the plurality of first injection holes 61. SiCl4 is introduced into the nozzle 56 through the nozzle inlet 57 and ejected from the plurality of second injection holes 62. CH3CN is introduced into the nozzle 56 through the nozzle inlet (not shown) and ejected from the plurality of third injection holes (not shown). H2 gas, N2 gas, Ar gas, etc., can be used as carrier gas. In this disclosure, the gas containing the feed gas and the carrier gas is referred to as the reaction gas.

[0182] When forming a hard granular layer, the following conditions (i) and (ii) are used.

[0183] (i) changing the percentage of the volume flow V1 of CH3CN relative to the volume flow V of the entire reaction gas, (V1 / V)×100. For example, the percentage (V1 / V)×100 is gradually increased during the period from the start to the end of the formation of the hard particle layer.

[0184] (ii) changing the percentage of the flow rate of SiCl4 V Si relative to the total flow rate V of TiCl4 and SiCl4 Ti+Si , (V Si / V Ti+Si )×100. For example, the percentage (V Si / V Ti+Si )×100 is increased during the period from the start to the end of the formation of the hard particle layer.

[0185] By adopting the above conditions (i) and (ii), the composition of the first region and the second region of the hard particle layer can be changed. In the composition Ti (1-Xb) Si Xb CN of the first region and the composition Ti (1-Xs) Si Xs CN of the second region, it can be adjusted such that Xs and Xb satisfy the relationship Xs-Xb≥0.01 and 0<Xb<Xs≤0.10.

[0186] When forming the hard particle layer, in order to adjust the composition Ti (1-Xb) Si Xb CN of the first region and the composition Ti (1-Xs) Si Xs CN of the second region so that Xs and Xb satisfy the relationship Xs-Xb≥0.01 and 0<Xb<Xs≤0.10, increasing the substrate temperature is also effective. In particular, in the composition Ti (1-Xb) Si Xb CN of the first region and the composition Ti (1-Xs) Si Xs CN of the second region, in order to set Xb to 0.07 or more and Xs to 0.09 or more, increasing the substrate temperature during the formation of the hard particle layer is effective.

[0187] When forming the hard particle layer, film formation is performed while rotating the nozzle. Accordingly, in the hard particles, the silicon concentration periodically changes along the growth direction of the hard particle layer.

[0188] In this process, the substrate temperature inside the reaction vessel is 800℃~900℃, and the pressure inside the reaction vessel is 50hPa~300hPa. The thickness of the hard particle layer can be controlled by adjusting the flow rate of the raw material gas and the film formation time. The period width of the silicon concentration in the hard particles can be controlled by adjusting the nozzle rotation speed and the film formation time.

[0189] In the formation of the hard particulate layer, the total gas flow rate of the reactants can be set to, for example, 70 L / min to 90 L / min. Here, "total gas flow rate" refers to the total volumetric flow rate introduced into the CVD furnace per unit time, taking the gas under standard conditions (0°C, one atmosphere) as an ideal gas.

[0190] (Other processes)

[0191] Next, the substrate 10 with the coating is cooled. The cooling rate, for example, will not exceed 5°C / min, and the cooling rate slows down as the temperature of the substrate 10 decreases.

[0192] In addition to the above-mentioned processes, heat treatment processes such as annealing, surface grinding, and shot peening can also be performed.

[0193] The cutting tool of Embodiment 1 can be obtained by the manufacturing method described above.

[0194] Example

[0195] The embodiments are described in more detail below. However, the embodiments are not limited to these embodiments.

[0196] <Preparation of Substrate>

[0197] As the substrate, a cemented carbide substrate is prepared. The substrate composition is Co: 6% by mass, NbC: 1.5% by mass, and the balance is WC. The substrate shape is CNMG120408N-GZ (indexable cutting insert manufactured by Sumitomo Electric Industries, Ltd.).

[0198] <Formation of the coating>

[0199] A coating was formed on the surface of the substrate using CVD. The composition of the coating and the average thickness of each layer for each sample are shown in Tables 1, 2, and 3. Columns marked with "-" in the tables indicate the absence of that layer.

[0200] Table 1

[0201]

[0202] Table 2

[0203]

[0204] Table 3

[0205]

[0206] The base layer (TiN layer), intermediate layer (TiCN layer), and surface layer (Al2O3 layer) shown in the table are formed by conventional CVD methods.

[0207] Regarding the hard particle layer of each sample shown in the table, use Figure 6 The CVD apparatus shown forms a hard granular layer. The nozzle of the CVD apparatus is equipped with a first injection hole, a second injection hole, and a third injection hole. The nozzle rotation speed, substrate temperature, and pressure during the formation of the hard granular layer in each sample are shown in Tables 4, 5, and 6.

[0208] Table 4

[0209]

[0210] Table 5

[0211]

[0212] Table 6

[0213]

[0214] In samples 1 through 39, the percentage (V1 / V)×100 of the volumetric flow rate V1 of CH3CN relative to the total volumetric flow rate V of the reactant gas was gradually increased from the start to the end of the formation of the hard particle layer. The changes in the percentage (V1 / V)×100 are shown in Tables 4, 5, and 6. For example, in sample 1, the percentage (V1 / V)×100 was gradually increased from 0.4% to 0.5%.

[0215] In samples 101 to 109, the percentage (V1 / V) × 100 was maintained constant during the formation of the hard particle layer. The percentage (V1 / V) × 100 is shown in Tables 4, 5, and 6. For example, in sample 101, the percentage (V1 / V) × 100 was maintained at 0.4%.

[0216] In samples 1 to 39, during the period from the start to the end of the formation of the hard particle layer, the flow rate V of SiCl4 was increased. Si The total flow rate V relative to TiCl4 and SiCl4 Ti+Si percentage (V) Si / V Ti+Si The percentage (V) increases by 100. Si / V Ti+SiThe changes in percentage (V) × 100 are shown in Tables 4, 5, and 6. For example, in sample 1, the percentage (V) × 100 is... Si / V Ti+Si The percentage ()×100 increases from 20% to 25%.

[0217] In samples 101 to 109, during the formation of the hard particle layer, the percentage (V) Si / V Ti+Si The percentage (V) remains constant at 100. Si / V Ti+Si )×100 as shown in Tables 4, 5, and 6. For example, in sample 101, the percentage (V) Si / V Ti+Si The value of 100 remains at 20%.

[0218] In samples 17 and 29–39, the substrate temperature was increased during the formation of the hard particle layer. The changes in substrate temperature are shown in Tables 5 and 6. For example, in sample 17, the substrate temperature was increased from 850°C to 870°C. In the other samples, the substrate temperature was maintained constant during the formation of the hard particle layer.

[0219] Afterwards, the substrate was cooled to obtain the cutting tools for each sample.

[0220] <Composition of the Hard Granular Layer>

[0221] When the hard particle layer was observed using a bright field scanning electron microscope (BF-SEM) in the cutting tools of each sample, it was confirmed that the hard particle layer was composed of multiple hard particles.

[0222] <Composition of the Hard Granular Layer>

[0223] In the cutting tools of each sample, the composition of the first region of the hard particle layer, Ti, was determined by SEM-EDX. (1-Xb) Si Xb CN and the composition of the second region Ti (1-Xs) Si Xs CN was measured. The specific measurement method is as described in Embodiment 1. Based on the results obtained, Xb, Xs, and Xs-Xb are shown in Tables 7, 8, and 9.

[0224] <Crystal Structure of Hard Particles>

[0225] In the hard particle layer of the cutting tool for each sample, the crystal structure of the hard particles was confirmed by pattern analysis based on limited field-of-view electron beam diffraction. The results are shown in Tables 7, 8, and 9. In the tables, "cubic crystal" indicates that the hard particles have a cubic crystal structure. In the tables, "cubic crystal + amorphous" indicates that the hard particles contain both cubic crystal structure and amorphous material.

[0226] <Changes in silicon concentration in hard particles>

[0227] In the hard particles of the cutting tools of each sample, a variation in silicon concentration was confirmed along a first direction from the first principal surface of the hard particle layer toward the second principal surface. In the hard particles of all samples, a periodic variation in silicon concentration was confirmed along the first direction from the first principal surface of the hard particle layer toward the second principal surface.

[0228] <Period width of silicon concentration in hard particles>

[0229] In the hard particles of the cutting tool for each sample, the period width of silicon concentration along a first direction from the first principal surface of the hard particle layer toward the second principal surface was measured. The specific measurement method is as described in Embodiment 1. The results are shown in Tables 7, 8, and 9 under "Si Concentration Period Width".

[0230] <Tissue of the hard granular layer>

[0231] In the hard particle layer of the cutting tool for each sample, the percentage (N1 / N) × 100 of the number N1 of the first hard particles with an aspect ratio of 3 or more relative to the total number N of all hard particles constituting the hard particle layer was measured. The specific measurement method is as described in Embodiment 1. The results are shown in Tables 7, 8, and 9.

[0232] If the percentage (N1 / N)×100 of each sample is greater than 50%, the hard particle layer is judged to be a columnar structure.

[0233] <l t>

[0234] In the cutting tools of each sample, the ratio L / T of the length L of the hard particles along the first direction to the thickness T of the hard particle layer was measured. The specific measurement method is as described in Embodiment 1. The results are shown in Tables 7, 8, and 9.

[0235] Table 7

[0236]

[0237] Table 8

[0238]

[0239] Table 9

[0240]

[0241] <Cutting Experiment 1>

[0242] Using cutting tools from specimens 1 to 15 and specimens 101 to 103, cutting was performed under the following cutting conditions, and the cutting time until the flank wear reached 0.2 mm was measured. A longer cutting time indicates a longer tool life. The results are shown in Table 10.

[0243] <Cutting Conditions>

[0244] Material to be cut: FCD700 round bar

[0245] Retainer: DCNL2525M12 (manufactured by Sumitomo Electric Industries, Ltd.)

[0246] Insert: CNMG120408N-GZ

[0247] Cutting speed Vc: 100m / min

[0248] Feed f: 0.3mm / rev

[0249] Cutting depth (ap): 1.5mm

[0250] Cutting fluid: Available (wet type)

[0251] Table 10

[0252]

[0253] <Evaluation>

[0254] The cutting tools of Specimens 1 to 15 correspond to the Examples. The cutting tools of Specimens 101 to 103 correspond to the Comparative Examples. It was confirmed that the cutting tools of Specimens 1 to 15 have a longer tool life than those of Specimens 101 to 103 when cutting materials with high cutting resistance.

[0255] <Cutting Experiment 2>

[0256] Using the cutting tools of specimens 16–27 and 104–106, cutting was performed under the following cutting conditions, and the cutting time until the flank wear reached 0.2 mm was measured. A longer cutting time indicates a longer tool life. The results are shown in Table 11.

[0257] <Cutting Conditions>

[0258] Material to be cut: FCD700 round bar

[0259] Retainer: DCNL2525M12 (manufactured by Sumitomo Electric Industries, Ltd.)

[0260] Insert: CNMG120408N-GZ

[0261] Cutting speed Vc: 140m / min

[0262] Feed f: 0.3mm / rev

[0263] Cutting depth (ap): 1.5mm

[0264] Cutting fluid: Available (wet type)

[0265] Table 11

[0266]

[0267] <Evaluation>

[0268] The cutting tools of specimens 16 to 27 correspond to the examples. The cutting tools of specimens 104 to 106 correspond to the comparative examples. It was confirmed that the cutting tools of specimens 16 to 27 have a longer tool life than those of specimens 104 to 106 when cutting materials with high cutting resistance.

[0269] <Cutting Test 3>

[0270] Using cutting tools from specimens 28 to 39 and 107 to 109, cutting was performed under the following cutting conditions, and the cutting time until the flank wear reached 0.2 mm was measured. A longer cutting time indicates a longer tool life. The results are shown in Table 12.

[0271] <Cutting Conditions>

[0272] Material to be cut: FCD700 round bar

[0273] Retainer: DCNL2525M12 (manufactured by Sumitomo Electric Industries, Ltd.)

[0274] Insert: CNMG120408N-GZ

[0275] Cutting speed Vc: 180m / min

[0276] Feed f: 0.3mm / rev

[0277] Cutting depth (ap): 1.5mm

[0278] Cutting fluid: Available (wet type)

[0279] Table 12

[0280]

[0281] <Evaluation>

[0282] The cutting tools of specimens 28 to 39 correspond to the examples. The cutting tools of specimens 107 to 109 correspond to the comparative examples. It was confirmed that the cutting tools of specimens 28 to 39 have a longer tool life than those of specimens 107 to 109 when cutting materials with high cutting resistance.

[0283] The embodiments and examples of this disclosure have been described above, but it is also intended from the outset that the above-described embodiments and examples may be appropriately combined or modified.

[0284] The embodiments and examples disclosed herein should be considered exemplary in all respects, and not restrictive. The scope of the invention is defined not by the foregoing embodiments and examples, but by the claims, and is intended to include all modifications equivalent to and within the scope of the claims.

[0285] Explanation of reference numerals in the attached figures

[0286] 1: Cutting tool; 10: Substrate; 11: Hard particle layer; 12: Base layer; 13: Surface layer; 14: Intermediate layer; 15: Coating; 50: CVD device; 52: Substrate mounting fixture; 53: Reaction vessel; 54: Temperature control device; 55, 57: Inlet; 56: Nozzle; 59: Exhaust pipe; 60: Exhaust port; 61: First injection hole; 62: Second injection hole; A1: First region; A2: Second region; S1, S2: Imaginary surfaces.< / l>

Claims

1. A cutting tool comprising a substrate and a coating disposed on said substrate, wherein, The coating comprises a rigid granular layer. The hard particle layer is composed of multiple hard particles, which are made of titanium, silicon, carbon, and nitrogen. The hard particle layer includes a first region and a second region. The first region is the region enclosed by a first main surface on the substrate side of the hard particle layer and an imaginary surface S1 at a distance of 0.5 μm from the first main surface on the hard particle layer side. The second region is the region enclosed by the second main surface of the hard particle layer opposite to the first main surface and an imaginary surface S2 located 0.5 μm away from the second main surface on the side of the hard particle layer. The first region is composed of Ti (1-Xb) Si Xb CN The second region is composed of Ti (1-Xs) Si Xs CN The Xs and Xb satisfy the relationships Xs-Xb≥0.01 and 0<Xb<Xs≤0.

10. The hard particles have a cubic crystal structure. In the hard particles, the concentration of silicon varies periodically along a first direction from the first main surface toward the second main surface.

2. The cutting tool according to claim 1, wherein, The hard particle layer has a columnar structure.

3. The cutting tool according to claim 2, wherein, The ratio of the length L1 of the hard particle along the first direction to the thickness T1 of the hard particle layer, L1 / T1, is 0.3 or more.

4. The cutting tool according to any one of claims 1 to 3, wherein, The period width of the silicon concentration in the hard particles along the first direction is greater than 3 nm and less than 20 nm.

5. The cutting tool according to any one of claims 1 to 4, wherein, The average thickness of the hard particle layer is greater than 2 μm and less than 15 μm.

6. The cutting tool according to any one of claims 1 to 5, wherein, The coating includes a base layer disposed between the substrate and the rigid particle layer. The substrate layer comprises at least one selected from the group consisting of TiN layer, TiC layer, TiCN layer, TiBN layer, TiCNO layer and Al2O3 layer.

7. The cutting tool according to any one of claims 1 to 6, wherein, The coating includes a surface layer disposed on the outermost surface of the coating. The surface layer is a TiN layer or an Al2O3 layer.

Images