Cutting tool

Abstract

Provided is a cutting tool having improved performance. A cutting tool provided according to one aspect includes: a substrate; and a coating on the substrate; the coating comprises a first layer and a second layer on the first layer; the first layer comprises TiCN with a Column (Column) structure, and the second layer comprises TiCN with a Column (Column) structure. The second layer comprises alpha-Al2O3 (aluminum oxide); in the first layer, the ratio of TC (311) to TC (111) (TC (311) / TC (111)) is 1.2 to 1.9 according to the formula 1.

Description

Technical Field

[0001] The present invention relates to a cutting tool. Background Art

[0002] Stainless steel is widely used as a metallic material with outstanding corrosion resistance and mechanical strength, but is also known as a work material with high cutting difficulty. The reasons for the reduced machinability of stainless steel may be its low thermal conductivity, high viscosity, and work hardening property. Therefore, in view of these characteristics, materials with high heat resistance, hardness, and particularly outstanding toughness have been developed for cutting tools used in stainless steel machining.

[0003] For example, KR 10-1326325 B1 discloses a WC-Co super-light alloy body with a CW ratio of 0.76 to 0.84 and containing 0.52 to 0.64 wt% of Cr, on which a coating of more than three TiC x N y O z layers and an α-Al2O3 layer with a thickness of 4.1 to 6.9 μm is deposited for an insert for stainless steel machining.

[0004] EP1528125 B1 is composed of a binder-like concentrated surface area containing Ti, Nb, and Ta with a ratio of Ta to Nb of 1.0 to 3.0 and a ratio of Ti to Nb of 0.5 to 1.5, with a thickness of 20 to 40 μm, a tungsten carbide substrate with an average chip length of 0.9 to 1.3 μm, and an oxide layer composed of cylindrical α-Al2O3 particles with structure coefficients of

[0005] TC012 = 2.5 to 3.5, TC024 > 0.6 × TC012, and TC104, TC110, TC113, TC116 < 0.3, and a coating of an MTCVDTi(C, N) layer for a cutting tool for stainless steel machining. Summary of the Invention

[0006] An object of the present invention is to provide a cutting tool with improved wear resistance and toughness, and preferably, a cutting tool optimized for cutting stainless steel.

[0007] Another object of the present invention is to provide a cutting tool with an extended service life.

[0008] The objects of the present invention are not limited to the above-mentioned objects. Other objects and advantages of the present invention that are not mentioned can be further understood from the following description, and can be further clearly understood through the embodiments of the present invention. Obviously, the objects and advantages of the invention can be achieved by the means described in the specification and their combinations.

[0009] According to a first aspect of the present invention, there is provided a cutting tool, preferably comprising: a substrate; and a coating on the substrate; the coating comprising a first layer and a second layer on the first layer; the first layer comprising TiCN having a columnar structure; the second layer comprising α-Al2O3; in the first layer, according to the following formula 1, the ratio of TC(311) to TC(111) with respect to TC(111) is from 1.2 to 1.9.

[0010] [Formula 1]

[0011]

[0012] In formula 1, TC(hkl) is the texture coefficient of each diffraction peak on the crystal plane (hkl), I(hkl) is the measured integrated intensity of the crystal plane (hkl) of the sample, I0(hkl) is the standard intensity of the standard powder sample according to the powder diffraction file (PDF) of the International Center for Diffraction Data (ICDD), and n is the number of reflection planes used for the calculation of the texture coefficient.

[0013] According to a second aspect of the present invention, based on the first aspect, preferably, the substrate is composed of a first hard phase, a second hard phase and a binding phase, the saturation magnetization of the substrate is 85 to 92%, and the coercive force of the substrate is 137 to 159 Oe.

[0014] According to a third aspect of the present invention, based on the first or second aspect, preferably, the substrate may include a binding phase enrichment layer.

[0015] According to a fourth aspect of the present invention, based on one of the first to third aspects, preferably, in the second layer, the ratio of TC(006) to the higher value of TC(012) and TC(110) (TC(006) / (higher value of TC(012) and TC(110))) is from 1.4 to 3.3.

[0016] According to the fifth aspect of the present invention, in one of the first to fourth aspects, preferably, in the first layer, among TC(111), TC(200), TC(220), TC(311) and TC(422), TC(311) is the highest and TC(111) is the second highest; in the second layer, among TC(012), TC(104), TC(110), TC(006), TC(113) and TC(116), TC(006) is the highest, and one of TC(110) and TC(012)

[0017] is the second highest.

[0018] According to the sixth aspect of the present invention, in one of the first to fifth aspects, preferably, in the second layer, the sum of TC(012), TC(104) and TC(110) is greater than or equal to 2 and less than 3.5.

[0019] According to the seventh aspect of the present invention, in one of the first to sixth aspects, preferably, in the second layer, the ratio ((TC(012)+TC(104)) / TC(110)) of the sum of TC(012) and TC(104) to TC(110) is greater than or equal to 1 and less than 2.5.

[0020] According to the eighth aspect of the present invention, in one of the first to seventh aspects, preferably, the coating further includes: a third layer disposed between the substrate and the first layer; the third layer may include TiN.

[0021] According to the ninth aspect of the present invention, in one of the first to eighth aspects, preferably, the coating further includes: a fourth layer disposed between the first layer and the second layer; the fourth layer includes at least one selected from the group consisting of TiC, TiCN, TiCNO, TiCO and TiNO.

[0022] According to the tenth aspect of the present invention, in one of the first to ninth aspects, preferably, the coating further includes: a fifth layer on the second layer; the fifth layer may include at least one of TiC, TiN and TiCN.

[0023] According to the eleventh aspect of the present invention, preferably, it includes: a substrate; and a coating on the substrate; the coating includes a first layer and a second layer on the first layer; the first layer includes TiCN having a columnar crystal structure; the second layer includes α-Al2O3; in the second layer, according to Formula 1, the ratio ((TC(012)+TC(104)) / TC(110)) of the sum of TC(012) and TC(104) to TC(110) is 1 or more and 2.5 or less. Here, the eleventh aspect of the present invention is characterized by at least one of the first to tenth aspects, or by several of the following embodiments.

[0024] The above technical solution does not list all the features of the present invention. Various features of the present invention, their advantages and beneficial effects can be understood in more detail by referring to the following specific description.

[0025] According to one aspect of the present invention, its beneficial effect is that a cutting tool with improved wear resistance and toughness can be achieved.

[0026] According to another aspect of the present invention, its beneficial effect is that a cutting tool with an extended lifespan can be achieved.

[0027] In addition to the above beneficial effects, the specific beneficial effects of the present invention will also be described while describing the specific content required to implement the invention. Furthermore, the effects of the present invention are not limited to the effects described above, and can be easily achieved through the devices and their combinations described in the specification. Description of the Drawings

[0028] Figure 1 is a cross-sectional view of a cutting tool according to an embodiment of the present invention;

[0029] Figure 2 is a cross-sectional view of a cutting tool according to another embodiment of the present invention.

[0030] Symbol Description

[0031] 10: Substrate; 20: Coating; 21: First layer; 22: Second layer;

[0032] 23: Third layer; 24: Fourth layer; 25: Fifth layer; 100: Cutting tool. Detailed Description of the Embodiments

[0033] In this specification, the singular form also includes the plural form unless otherwise specifically indicated in the context.

[0034] As used in this specification, the terms "comprise" or "comprising" are used to specify the presence of the shapes, steps, numbers, actions, components, elements, and / or combinations thereof described in the specification, and do not exclude the presence or addition of one or more other shapes, steps, numbers, actions, components, elements, and / or combinations thereof.

[0035] As used in this specification, "at least one of a, b, and c" may include a, b, or c individually, or may include combinations of two or more selected from the group consisting of a, b, and c.

[0036] When describing various embodiments in this specification, unless otherwise stated to the contrary, the various embodiments may be combined. Here, the beneficial effects of the present invention can be defined as including the effects generated by each embodiment and the effects generated by the organic combination of each embodiment. For example, even if embodiments 1 and 2 are described separately in this specification, unless the context is clearly different, embodiments 1 and 2 can be organically combined with each other, and the beneficial effects of the present invention can include the effects generated by the combination of embodiments 1 and 2.

[0037] In this specification, the numerical range indicated by the term "to" means a numerical range that includes the values described before and after the term, with the lower limit value and the upper limit value. When the upper and lower limit values of any numerical range are each represented by a plurality of values, the numerical range disclosed in this specification can be understood as any numerical range that takes any one of the plurality of lower limit values and any one of the plurality of upper limit values as the lower limit value and the upper limit value, respectively. For example, if the specification describes a to b, or c to d, it can be understood as describing a or more and b or less, a or more and d or less, c or more and d or less, or c or more and b or less.

[0038] In this specification, terms such as "about" or "substantially" refer to a reasonable deviation amount of the term modified so that the final result does not change significantly. These terms can be interpreted as including a deviation of at least ±5% or at least ±10% within the range where the deviation does not invalidate the meaning of the word.

[0039] In this specification, when observing the region where a "layer" exists, in addition to the state formed over the entire region, it may also include a state formed only on a part of the region. For example, it may be defined to include a flat form, a non-flat form, and a combination thereof on the layer surface; or a continuous form, a discontinuous form, and a combination thereof. For example, when another component is configured as a layer directly on top of a component, the coverage of the surface of the said one component by the other component may be defined as 1% or more, 5% or more, 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, 85% or more, 90% or more, 95% or more, or 99% or more.

[0040] In this specification, the particle size of particles may mean the average diameter of each particle observed using an Electron Backscatter Diffraction (EBSD) apparatus.

[0041] In this specification, the XRD (X-ray diffraction) analysis method is an analysis method in which X-rays are diffracted onto a specimen and the internal information of the specimen is displayed in a graph. Through this analysis method, peaks appear at the characteristic angles of multiple phases, so it is possible to confirm what phases the specimen is composed of inside. Specifically, the result of the XRD analysis method can be displayed in a graph with 2θ on the x-axis and intensity on the y-axis.

[0042] According to an aspect of the present invention, there is provided a cutting tool including a substrate; and a coating on the substrate; the coating includes a first layer and a second layer on the first layer, the first layer includes TiCN having a columnar structure, the second layer includes α-Al2O3, and in the first layer, based on the following formula 1, the ratio of TC(311) to TC(111) (TC(311) / TC(111)) is 1.2 to 1.9. According to an aspect of the present invention, the first layer includes TiCN having a columnar structure, the second layer includes α-Al2O3, and in the first layer, based on the following formula 1, the ratio of TC(311) to TC(111) (TC(311) / TC(111)) satisfies 1.2 to 1.9, thereby enabling a cutting tool with outstanding wear resistance and toughness to be achieved. Specifically, when the ratio of TC(311) to TC(111), TC(311) / TC(111), is less than the numerical range, there may be a problem of reduced toughness of the first layer, and when it exceeds the numerical range, there may be a problem that crack propagation becomes easy.

[0043] The structure of the present invention will be described in detail below with reference to the accompanying drawings.

[0044] According to Figure 1 , the cutting tool of the present invention includes a substrate 10 and a coating 20 disposed on the substrate 10.

[0045] Substrate 10

[0046] The substrate 10 of the present invention helps to form the subsequent coating 20 and also increases the hardness and strength of the cutting tool.

[0047] In several embodiments of the present invention, the substrate 10 may be composed of a first hard phase, a second hard phase, and a binding phase.

[0048] First hard phase

[0049] The first hard phase of the present invention is composed of tungsten carbide (WC) and can be a phase that imparts hardness and strength to the cemented carbide.

[0050] In several embodiments of the present invention, the content of the first hard phase, based on the total weight of the substrate, may be 74 to 95 wt%, 75 to 91 wt%, 76 to 90 wt%, 77 to 89 wt%, 80 to 88 wt%, 81 to 85 wt%, or 82 to 84 wt%. According to several embodiments of the present invention, when the content of the first hard phase is within the above numerical range, the hardness of the cemented carbide is increased, wear resistance is improved, the toughness of the cemented carbide is enhanced, and the resistance to chipping is improved, thereby further extending the life of the cutting tool. In several examples, based on the substrate (cemented carbide as a sample), the content of tungsten carbide (WC) can be analyzed by EDS (Energy Dispersive X-ray Spectroscopy).

[0051] In several embodiments of the present invention, the particle size of tungsten carbide (WC) may be 2 to 7 μm or 3 to 4 μm. According to several embodiments of the present invention, when the particle size of tungsten carbide (WC) is within the above numerical range, the chemical reactivity resistance of the cemented carbide is maintained at an appropriate level while the flexural strength and resistance to chipping are fully realized.

[0052] Second hard phase

[0053] The second hard phase of the present invention may include at least one of carbides, nitrides, and carbonitrides of one or more metals in Groups 4, 5, and 6 of the periodic table to improve the hardness and toughness of the cemented carbide, thereby extending the life of the cutting tool.

[0054] In several examples, at least one or more metals in Group 4, Group 5, and Group 6 of the periodic table may include one or more selected from the group consisting of Zr, Hf, Rf, Ce, Th, V, Nb, Ta, Db, Pr, Pa, Cr, Mo, W, Ti, Sg, Nd, and U. Specifically, it may include at least one cubic compound selected from the group consisting of Ta, Nb, Ti, and W. More specifically, Ta, Nb, Ti, and W may all be included. Specifically, when the cubic compound is used as the second hard phase, the mechanical properties of the cemented carbide will be better, thereby extending the life of the cutting tool.

[0055] In several embodiments of the present invention, the second hard phase may include at least one of TaNbC, TiCN, and WTiC. According to several embodiments of the present invention, since the second hard phase includes at least one of TaNbC, TiCN, and WTiC, the mechanical properties of the cemented carbide are more prominent. In several examples, based on the total weight of the substrate, the content of TaNbC may be 2 to 6 weight percent, 2 to 5 weight percent, or 3 to 4 weight percent, the content of TiCN may be 0.5 to 3.2 weight percent, 1 to 3 weight percent, or 1 to 2 weight percent, and the content of WTiC may be 1.5 to 5.6 weight percent, 2 to 5 weight percent, or 3 to 4 weight percent. According to several embodiments of the present invention, when the contents of TaNbC, TiCN, and WTiC meet the above numerical ranges, the toughness of the cemented carbide can be further improved. In several examples, the content of the second hard phase can be analyzed by the EDS analysis method based on the cemented carbide sample.

[0056] In several embodiments of the present invention, the weight ratio of Ta, Ti, and Nb may be 2.5 - 3.5:2.5 - 3.5:0.5 - 1.5, specifically 3:3:1. In several examples, the weight ratio of Ta, Ti, and Nb can be analyzed by the EDS analysis method based on the cemented carbide sample.

[0057] In several embodiments of the present invention, the content of the second hard phase may be 3 to 15 weight percent, 4 to 13 weight percent, 6 to 12 weight percent, 7 to 10 weight percent, or 8 to 9 weight percent based on the total weight of the substrate. According to several embodiments of the present invention, when the content of the second hard phase satisfies the numerical range, the hardness of the cemented carbide is increased, the wear resistance is improved, the toughness of the cemented carbide is increased, and the resistance to chipping is improved, thereby further extending the life of the cutting tool.

[0058] Bonding phase

[0059] The binder phase of the present invention may contain at least one of Co and Ni, thereby improving the toughness and hardness of the cemented carbide.

[0060] In several embodiments of the present invention, based on the total weight of the substrate, the content of the binder phase may be 5 to 11 weight percent, 6 to 10 weight percent, 7 to 9 weight percent, or 7 to 8 weight percent. According to several embodiments of the present invention, when the content of the binder phase is within the numerical range, the wear resistance and the resistance to chipping of the cemented carbide are improved in a balanced manner, thereby extending the life of the cutting tool. In several examples, based on the cemented carbide sample, the content of the binder phase can be analyzed by the EDS analysis method.

[0061] Parameters of the substrate

[0062] On the one hand, the saturation magnetization of the substrate (e.g., cemented carbide) can be calculated by the following mathematical formula 1.

[0063] [Mathematical formula 1]

[0064] Saturation magnetization of the substrate (%) = {[M1 (emu)] / [M2 (emu / g) × M3 (g)]}

[0065] In the mathematical formula 1, M1 is the saturation magnetization of the substrate (emu), M2 is the theoretical saturation magnetization of Co (emu / g), and M3 is the content of Co in the substrate (g). Further, the saturation magnetization of the substrate (%) refers to the ratio of the saturation magnetization of the substrate (emu) to the theoretical saturation magnetization of Co (emu) contained in the substrate. In several examples, the saturation magnetization of the substrate (emu) can be measured by a well-known magnetic property measuring device. In addition, the theoretical saturation magnetization of Co may be a well-known value. The saturation magnetization generally depends on the Co content and carbon content of the cemented carbide. Controlling the saturation magnetization within an appropriate range may mean rationalizing the carbon content with respect to the content of the constituent elements, thereby adjusting the structure so as not to contain the η phase or free carbon.

[0066] In several embodiments of the present invention, the saturation magnetization of the substrate 10 may be 85 to 92%, 86 to 91%, 87 to 90%, 88 to 90% or 89 to 90%. According to several embodiments of the present invention, when the saturation magnetization of the substrate is within the above numerical range, the carbon content can be adjusted to a relatively high level within the range where η-phase or free carbon is not formed, thereby further enhancing the toughness of the cemented carbide.

[0067] The coercive force is usually adjusted by the particle size of the tungsten carbide (WC) hard phase and the thickness of the binder phase. The smaller the particle size of tungsten carbide (WC) and the greater the thickness of the binder phase, the higher the coercive force becomes. For example, a high coercive force will increase the hardness of the cemented carbide, but reduce the toughness.

[0068] In several embodiments of the present invention, the coercive force of the substrate may be 137 to 159 Oe, 140 to 155 Oe, 141 to 154 Oe, 142 to 152 Oe, 143 to 150 Oe, 144 to 148 Oe or 145 to 146 Oe. According to several embodiments of the present invention, when the coercive force and saturation magnetization of the substrate are within the above numerical range, the thickness of the binder phase between the WC particles is adjusted to an appropriate level, and the content of the metal component or carbon of the hard phase dissolved in the binder phase is adjusted to an appropriate level through regulation, thereby enabling a cemented carbide substrate with high toughness and hardness to be achieved.

[0069] Additional constituent elements

[0070] In several embodiments of the present invention, the substrate 10 may include a binder phase enrichment layer (not shown) that improves the toughness of the substrate surface, reduces the difference in thermal expansion coefficient from the coating described later, and thus alleviates the thermal cracks of the coating.

[0071] In several examples, the binder phase enrichment layer may be in the form of a layer having a depth of 10 to 30 μm or 15 to 25 μm from the surface to the inside of the substrate 10. According to several examples, when the thickness of the binder phase incubation layer satisfies the above numerical range, the toughness of the substrate surface can be improved, the thermal cracks of the coating can be sufficiently reduced, and the wear resistance of the substrate can be maintained at an appropriate level.

[0072] In several examples, the binder phase incubation layer may not include the second hard phase, but may include the above-mentioned binder phase. Specifically, the binder phase incubation layer may contain 1.2 to 1.7 times more binder phase than the rest of the substrate except the binder phase incubation layer.

[0073] In several embodiments of the present invention, the substrate 10 may have an inclined surface participating in cutting, a flank surface in contact with the inclined surface, and a cutting edge portion formed on the ridge line where the inclined surface and the flank surface intersect.

[0074] Coating 20

[0075] The coating 20 of the present invention includes a first layer 21 and a second layer 22 on the first layer 21.

[0076] First layer

[0077] The first layer 21 of the present invention includes TiCN having a columnar structure. In this state, the columnar structure may refer to a structure having columnar crystals in the thickness direction of the first layer 21. Specifically, since the first layer 21 includes TiCN having a columnar structure, the texture orientation of the second layer (α-aluminum oxide) can be controlled while controlling and achieving adhesion to the second layer and its own defect resistance and wear resistance.

[0078] In several examples, the first layer 21 can be formed by an MT-CVD (Medium-temperature Chemical Vapor Deposition) process. Here, the MT-CVD process temperature can be carried out at a temperature of 800 to 950 °C. If the first layer is formed by an HT-CVD (High Temperature CVD) process carried out at a temperature above 1000 °C, not only will the substrate be damaged due to heating during film formation, but an equiaxed crystal structure will also be formed on the first layer, and thus it may be difficult to control the texture orientation of the second layer (α-aluminum oxide).

[0079] According to several embodiments of the present invention, in the first layer, among TC(111), TC(200), TC(220), TC(311), and TC(422), TC(311) can be the highest and TC(111) can be the second highest.

[0080] In the first layer 21 of the present invention, the ratio of TC(311) to TC(111) (TC(311) / TC(111)) is 1.2 to 1.9. Specifically, it can be 1.3 to 1.8, 1.35 to 1.60, 1.37 to 1.56, or 1.49 to 1.56. Here, if the ratio of TC(311) to TC(111) (TC(311) / TC(111)) is lower than the above numerical range, there may be a problem of a decrease in the toughness of the first layer, and if it exceeds the above numerical range, there may be a problem that crack propagation becomes easy.

[0081] [Formula 1]

[0082]

[0083] In the formula 1, TC(hkl) is the texture coefficient of each diffraction peak on the crystal plane with the crystal plane index (hkl), I(hkl) is the measured integrated intensity of the specimen crystal plane with the crystal plane index (hkl), I0(hkl) is the standard intensity of the standard powder specimen specified in the PDF (Powder Diffraction File) of the ICDD (International Center for Diffraction Data), and n is the number of reflecting planes used to calculate the texture coefficient. For example, in the first layer, the standard powder specimen is CNMG120408, and the PDF card number of the ICDD (International Center for Diffraction Data) can be 42 - 1489.

[0084] According to several embodiments of the present invention, in the first layer, among TC(111), TC(200), TC(220), TC(311), and TC(411), TC(311) is the highest, TC(111) is the second highest, and (TC(311) / TC(111)) satisfies 1.2 to 1.9, so that the preferentially grown (311) plane promotes the (006) orientation of the second layer (α - Al2O3). Therefore, although the film thickness is thin, it can have sufficient texture coefficient and can improve the fracture resistance of the first layer. In addition, since the (111) plane has a dense structure, the hardness of the first layer can be increased, and the adhesion to the second layer can be improved, thereby effectively preventing the occurrence of peeling phenomenon.

[0085] According to several embodiments of the present invention, the texture coefficients TC(200), TC(220), and TC(422) of the (200) plane, (220) plane, and (422) plane other than the (311) plane and (111) plane can all be less than 1.1.

[0086] In several embodiments of the present invention, TC(311) of the first layer 21 can exceed 1.5 and be less than 3.0, 1.8 to 2.8, 1.9 to 2.5, or 1.9 to 2.3.

[0087] In several examples, the thickness of the first layer 21 is, specifically, can be 1 to 5 μm, 2 to 5 μm, 2 to 4 μm, or 3 to 4 μm.

[0088] Second layer

[0089] The second layer 22 of the present invention can improve the hardness and toughness of the coating.

[0090] The second layer 22 of the present invention includes α-Al2O3. Specifically, since α-aluminum oxide is included in the second layer 22, an effect of outstanding hardness and wear resistance can be achieved at high temperatures as compared with other crystal structures.

[0091] In several examples, the second layer 22 may include α-Al2O3 having a columnar structure. Specifically, since the second layer 22 includes α-aluminum oxide having a columnar structure, the occurrence of coating peeling (chipping) due to the interaction with the texture orientation of the first layer can be effectively suppressed, and at the same time, the effect of maintaining thermal conductivity can be achieved.

[0092] On the other hand, the structure coefficient can also be measured in the second layer 22 according to Formula 1. Here, the standard powder sample is CNMG120408, and the card number of the standard powder sample specified in the PDF (Powder Diffraction File) of the ICDD (International Center for Diffraction Data) may be 42-1212.

[0093] In several embodiments of the present invention, among TC(012), TC(104), TC(110), TC(006), TC(113), and TC(116) in the second layer, TC(006) is the highest, and one of TC(110) and TC(012) may be the second highest.

[0094] In several embodiments of the present invention, in the second layer, the ratio of TC(006) to the higher value of TC(012) and TC(110) (TC(006) / (higher value of TC(012) and TC(110))) may be 1.4 to 3.3, may be 1.5 to 3.0, 1.8 to 3.0, 2.0 to 3.0, or 2.07 to 2.87. According to several embodiments of the present invention, when the ratio of TC(006) to the higher value of TC(012) and TC(110) (TC(006) / (higher value of TC(012) and TC(110))) in the second layer is within the above numerical range, the occurrence of coating peeling (chipping) due to the interaction with the texture orientation of the first layer can be effectively suppressed, and at the same time, the effect of maintaining the thermal conductivity can be achieved.

[0095] According to several embodiments of the present invention, the structure coefficients TC(113) and TC(116) of the (113) surface and (116) surface, other than the (006) surface, (012) surface, (104) surface, and (110) surface, can both be less than 0.4.

[0096] In several embodiments of the present invention, the sum of TC(012), TC(104), and TC(110) in the second layer can be 2 or more and less than 3.5, 2.1 to 3.3, 2.2 to 3.0, 2.3 to 2.9, or 2.4 to 2.82. According to several embodiments of the present invention, when the sum of TC(012), TC(104), and TC(110) satisfies the above numerical range, it is possible to effectively suppress the occurrence of coating peeling (fragmentation) phenomenon caused by the interaction with the texture orientation of the first layer while achieving the effect of maintaining the thermal conductivity.

[0097] In several embodiments of the present invention, the ratio ((TC(012)+TC(104)) / TC(110)) of the sum of TC(012) and TC(104) to TC(110) in the second layer can be 1 or more and less than 2.5, 1.2 or more and less than 2.5, 1.5 or more and less than 2.5, 1.7 or more and less than 2.5, 1.9 or more and less than 2.5, or 1.96 or more and 2.47 or less. According to several embodiments of the present invention, since the ratio ((TC(012)+TC(104)) / TC(110)) of the sum of TC(012) and TC(104) to TC(110) satisfies the above numerical range, it is possible to effectively suppress the occurrence of coating peeling (fragmentation) phenomenon caused by the interaction with the texture orientation of the first layer while achieving the effect of maintaining the thermal conductivity.

[0098] In several examples, the thickness of the second layer 22 can specifically be 0.5 to 4.0 μm, 1.0 to 3.0 μm, or 1.5 to 2.5 μm.

[0099] Third layer

[0100] In several embodiments of the present invention, the coating 20 may further include a third layer 23 disposed between the substrate 10 and the first layer 21.

[0101] The third layer 23 of the present invention can improve the adhesion of the coating to the substrate surface and can effectively prevent the components of the substrate from diffusing into the coating.

[0102] Specifically, the third layer 23 may include TiN.

[0103] In several examples, the thickness of the third layer 23 is not particularly limited. Specifically, it can be 0.1 to 2.0 μm, 0.2 to 1.5 μm, 0.3 to 1.2 μm, 0.4 to 1.1 μm, or 0.5 to 1.0 μm.

[0104] Fourth layer

[0105] In several embodiments of the present invention, the coating 20 may further include a fourth layer 24 disposed between the first layer 21 and the second layer 22. Specifically, the fourth layer 24 may be disposed between the first layer 21 and the second layer 22, serving to assist in the bonding between the first layer 21 and the second layer 22.

[0106] In several embodiments of the present invention, the fourth layer 24 may include at least one selected from the group consisting of TiC, TiCN, TiCNO, TiCO, and TiNO. Specifically, since the fourth layer 24 includes at least one selected from the group consisting of TiC, TiCN, TiCNO, TiCO, and TiNO, the bonding between the first layer 21 and the second layer 22 can be further improved, and thus more prominent bonding strength can be achieved between the layers forming the coating.

[0107] In several examples, the fourth layer 24 may include TiCNO that can grow into a columnar structure. Specifically, since the fourth layer 24 includes TiCNO having the columnar crystal structure, the texture orientation control effect of the second layer can be not disturbed.

[0108] In several examples, the fourth layer 24 may not include TiCN having an equiaxed crystal structure. If the fourth layer includes TiCN having an equiaxed crystal structure, there may be a problem of disturbing the texture orientation control of the above-mentioned second layer 22.

[0109] In several examples, the thickness of the fourth layer 24 can be 0.1 to 1.0 μm, 0.2 to 0.9 μm, 0.3 to 0.8 μm, 0.4 to 0.7 μm, or 0.4 to 6.6 μm.

[0110] Fifth layer

[0111] Figure 2 It is a cross-sectional view of a cutting tool according to another embodiment of the present invention. Descriptions that are the same as or repetitive of the above parts are briefly described or omitted.

[0112] According to Figure 2, in several embodiments of the present invention, the coating 20 may further include a fifth layer 25 on the second layer 22. Specifically, it may further include a fifth layer 25 disposed directly on the second layer 22. In several examples, the fifth layer 25 may be the uppermost layer or the outermost corner layer of the coating 20.

[0113] The fifth layer 25 of the present invention can effectively prevent the wear resistance of the coating from decreasing and can function as a wear identification layer.

[0114] In several examples, the fifth layer 25 may not be particularly limited. Specifically, it may include at least one of TiC, TiN, and TiCN.

[0115] In several examples, the thickness of the fifth layer 25 is not particularly limited. Specifically, it may be 0.1 to 3.0 μm.

[0116] Relationship between constituent elements

[0117] In several embodiments of the present invention, the substrate 10 may have an inclined surface participating in cutting, a flank surface in contact with the inclined surface, and a cutting edge portion formed on the ridge line where the inclined surface and the flank surface intersect. In this state, the coating 20 of several embodiments can be formed on at least one of the inclined surface, the flank surface, and the cutting edge portion.

[0118] For example, the coating 20 may be in at least one of the inclined surface and the flank surface in some forms. Here, the coating 20 on the cutting edge portion can remove the second layer 22 through post-treatment such as spraying or buffing, or can make the first layer 21 the outermost corner layer through treatment. Due to the high toughness of the first layer 21, it can directly contact the material to be cut, thereby improving the efficiency of cutting processing.

[0119] The embodiments of the present invention will be described in detail below so that those of ordinary skill in the art to which the present invention pertains can easily implement them. However, this is only an example, and the scope of the claims of the present invention is not limited by the following content.

[0120] [Manufacturing Example: Manufacturing of Cutting Tools]

[0121] <Example 1>

[0122] Steps for preparing the substrate:

[0123] Prepared a material composed of 83.7 wt% of the first hard phase (WC), 7.5 wt% of the binder phase (Co), 4 wt% of the second hard phase (TaNbC), 1.2 wt% of TiCN, and WTiC

[0124] A cemented carbide substrate composed of a combination of (3.6 wt%). Here, the cemented carbide substrate has a WC (tungsten carbide) particle size of 4 μm, a saturation magnetization of 89.75% and a coercive force of 145.1 Oe according to the following Mathematical Formula 1.

[0125] [Mathematical Formula 1]

[0126] Saturation magnetization of the substrate (%) = {[M1 (emu)] / [M2 (emu / g) × M3 (g)]}

[0127] In the Mathematical Formula 1, M1 is the saturation magnetization of the substrate (emu), M2 is the theoretical saturation magnetization of Co (emu / g), and M3 is the content of Co in the substrate (g). Further, the saturation magnetization of the substrate (%) refers to the ratio of the saturation magnetization (emu) of the substrate to the theoretical saturation magnetization (emu) of Co contained in the substrate. In several examples, the saturation magnetization of the substrate (emu) can be measured using a well-known magnetic property measuring device. And the theoretical saturation magnetization of Co can be a well-known value.

[0128] Steps for forming a coating on the substrate:

[0129] On the substrate, deposition is carried out under the deposition conditions described in the following List 1 to form a coating. Specifically, on the surface of the substrate, deposition is carried out in the order of the third layer (TiN, thickness = 0.5 μm), the first layer (MT-TiCN, thickness = 3.6 μm), the fourth layer (TiCNO, thickness = 0.4 μm), and the second layer (α-Al2O3, thickness = 2.4 μm), and then an insert of the CNMG120408 model is manufactured.

[0130]

Table 1

[0131]

[0132] <Examples 2 to 5>

[0133] Cutting tools were manufactured in the same manner as in Example 1, and Examples 2 to 5 with a maximum coating thickness deviation within 1 μm were manufactured.

[0134] <Comparative Examples 1 and 2: Preparation of commercial products>

[0135] Commercial Comparative Examples 1 and 2 with the characteristics shown in the following Table 2 were prepared.

[0136] [Experimental Example 1: Analysis of the tissue coefficients of the first and second layers]

[0137] The following Table 2 shows the texture coefficients (TC) of each diffraction peak of the first layer (MT-TiCN) in the cutting tools of the said embodiments and comparative examples, and the following Table 4 shows the texture coefficients of each diffraction peak of the second layer (α-Al2O3).

[0138] The texture coefficient is a value calculated according to the X-ray diffraction analysis method and can be calculated by the formula 2 described below. Specifically, an X-ray diffractometer (model: X'pert) manufactured by Malvern Panalytical is used, and XRD (X-ray diffraction) analysis is performed using a detector equipped with Bragg Brentano HD (hereinafter referred to as "BBHD") and Pixel3D. Copper (Cu) is used as the XRD electrode material, and a voltage of 45 kV and a Cu-Kα wavelength of 40 mA are used. A 1 / 2° anti-scattering slit and a 1 / 8° divergence slit are installed on the BBHD, and 1 / 2 Soller slits are fastened to the detector for use. The 2θ from 20° to 145° is measured by the θ-2θ method.

[0139] [Formula 1]

[0140]

[0141] In the said Formula 1, TC(hkl) is the texture coefficient (Texture Coefficient, TC) of each diffraction peak on the crystal plane index (hkl) plane, I(hkl) is the measured integrated intensity of the sample crystal plane index (hkl) plane, I0(hkl) is the standard intensity of the standard powder sample specified by the PDF (Powder Diffraction File) of the ICDD (International Center for Diffraction Data), and n is the number of reflecting planes used to calculate the texture coefficient. Here, the PDF (Powder Diffraction File) card number of the ICDD (International Center for Diffraction Data) is 42-1489 for the first layer (MT-TiCN) and 42-1212 for the second layer (α-Al2O3).

[0142]

Table 2

[0143]

[0144] According to Table 2, for the first layer, it was confirmed through Examples 1 to 5 that the ratio of TC(311) to TC(111), i.e., TC(311) / TC(111), satisfied 1.2 to 1.9 with respect to TC(111). Conversely, Comparative Examples 1 and 2 confirmed that the ratio of TC(311) to TC(111) (TC(311) / TC(111)) did not satisfy the said numerical range.

[0145] In addition, Examples 1 to 5 are characterized in that among TC(111), TC(200), TC(220), TC(311), and TC(422), TC(311) is the highest and TC(111)

[0146] is the second highest.

[0147] Conversely, Comparative Examples 1 and 2 show that among TC(111), TC(200), TC(220), TC(311), and TC(422), the value of TC(311) is the highest, but do not exhibit the characteristic that TC(111) is the second highest.

[0148]

Table 3

[0149]

[0150]

[0151] It was confirmed according to Table 3 that both the examples and the comparative examples commonly contained α-Al2O3 that preferentially grew on the (006) plane. However, different from Comparative Example 1 in which the structure coefficients for all planes other than the (006) plane were all less than 0.5, the sum of TC(012), TC(104), and TC(110) in Examples 1 to 5 was above 2 and less than 3.5, and it was confirmed that either TC(012) or TC(110) was the second highest, and the ratio of the higher value of TC(006) to the higher value of TC(012) and TC(110) was 1.4 to 3.3.

[0152] In addition, in Examples 1 to 5, the ratio of the sum of TC(012) and TC(104) to TC(110), i.e., ((TC(012)+TC(104)) / TC(110)), satisfied 1 or more and less than 2.5.

[0153] On the one hand, different from Examples 1 to 5, in Comparative Example 2, TC(104) was the second highest, and the ratio of the sum of TC(012) and TC(104) to TC(110), i.e., ((TC(012)+TC(104)) / TC(110)), was 2.5 or more, namely 2.8.

[0154] [Experimental Example 2: Performance Evaluation of Cutting Tools]

[0155] The wear resistance and toughness of the cutting tools of the examples and comparative examples were measured under the analysis conditions described in the following List 4, and the results are shown in the following List 5.

[0156] [Table 4]

[0157]

[0158]

[0159] [Table 5]

[0160]

[0161] It was confirmed in Table 5 that, for Examples 1 to 5 where the ratio of TC(311) to TC(111) of TC(111) in the first layer (TC(311) / TC(111)) satisfies 1.2 to 1.9, the wear resistance and defect resistance are outstanding compared with Comparative Examples 1 and 2 that do not satisfy the numerical range. Specifically, the wear resistance and toughness of Comparative Example 1 are not strong enough, and the toughness of Comparative Example 2 is outstanding, but the wear resistance is very poor, so it indicates that its performance is unbalanced.

[0162] The features described in the foregoing examples may be combined with other examples without explicit contrary description. Although the present invention has been described in detail with reference to the foregoing examples, those of ordinary skill in the art can still modify and improve the technical solutions described in the foregoing examples, and these modifications or improvements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions described in the examples of the present invention. All other examples obtained without creative work fall within the scope of protection of the present invention.

Claims

1. A cutting tool, characterized in that: include: Base material; and a coating on the substrate; the coating comprises a first layer and a second layer on the first layer; the first layer comprises TiCN having a columnar structure; the second layer comprises α-Al2O3; in the first layer, according to the following formula 1, the ratio of TC(311) relative to TC(111) (TC(311) / TC(111)) is between 1.2 and 1.9, and TC(422) is less than 1.1; In Formula 1, TC(hkl) is the texture coefficient (TC) of each diffraction peak on the crystal plane index (hkl) plane; I(hkl) is the measured integrated intensity of the crystal plane index (hkl) plane of the sample; I0(hkl) is the standard intensity of the standard powder sample specified in the powder diffraction file PDF (Powder Diffraction File) of the International Center for Diffraction Data (ICDD); n is the number of reflection planes used to calculate the texture coefficient.

2. The cutting tool according to claim 1, characterized in that The substrate is composed of a first hard phase, a second hard phase and a bonding phase; the saturation magnetic susceptibility of the substrate is 85 to 92% calculated according to the following mathematical formula 1, and the coercive force of the substrate is 137 to 159 Oe. Saturation magnetic susceptibility of substrate (%) = {[M1 (emu)] / [M2 (emu / g) × M3 (g)]} [Mathematical formula 1] In the mathematical formula 1, M1 is the saturation magnetization of the substrate (emu), M2 is the saturation magnetization of Co (emu / g), and M3 is the content of Co in the substrate (g).

3. The cutting tool according to claim 1, characterized in that The substrate includes a binder phase-enriched layer.

4. The cutting tool according to claim 1, characterized in that In the second layer, a ratio of TC(006) to a higher value of TC(012) and TC(110) (TC(006) / (higher value of TC(012) and TC(110))) is 1.4 to 3.

3.

5. The cutting tool according to claim 1, characterized in that In the first layer, among TC(111), TC(200), TC(220), TC(311) and TC(422), TC(311) is the highest, and TC(111) is the second highest; in the second layer, TC(012), TC(104), TC(110), TC(006), TC(113) and TC(116) are Among them, TC(006) is the highest, and one of TC(110) and TC(012) is the second highest.

6. The cutting tool according to claim 1, characterized in that In the second layer, the sum of TC(012), TC(104) and TC(110) is greater than 2 and less than 3.

5.

7. The cutting tool according to claim 1, characterized in that In the second layer, a ratio of the sum of TC(012) and TC(104) to TC(110) ((TC(012)+TC(104)) / TC(110)) is greater than 1 and less than 2.

5.

8. The cutting tool according to claim 1, characterized in that The coating further includes: a third layer disposed between the substrate and the first layer; the third layer includes TiN.

9. The cutting tool according to claim 1, characterized in that The coating layer further includes: a fourth layer disposed between the first layer and the second layer; the fourth layer includes at least one selected from the group consisting of TiC, TiCN, TiCNO, TiCO, and TiNO.

10. The cutting tool according to claim 1, characterized in that The coating further includes: a fifth layer on the second layer; the fifth layer includes at least one of TiC, TiN and TiCN.

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