KR102695334B1 - Cutting tool - Google Patents

Abstract

A cutting tool with improved performance is provided. According to one aspect, a cutting tool is provided, comprising: a substrate; and a coating layer on the substrate, wherein the coating layer comprises a first layer and a second layer on the first layer, wherein the first layer comprises TiCN having a columnar structure, and the second layer comprises α-Al ₂ O ₃ , wherein in the first layer, a ratio of TC (311) to TC (111) (TC (311) / TC (111)) according to Equation 1 is 1.2 to 1.9.

Description

CUTTING TOOL

The present invention relates to a cutting tool.

Stainless steel is widely used as a metal material with excellent corrosion resistance and mechanical strength, but at the same time, it is also known as a workpiece that is difficult to cut. The reason for the poor machinability of stainless steel may be the low thermal conductivity, high viscosity, and work hardening of stainless steel. In order to match these characteristics, grades that emphasize high heat resistance, hardness, and especially toughness are being developed and applied to cutting tools for stainless steel processing.

For example, KR 10-1326325 B1 discloses an insert for machining stainless steel, comprising a 4.1 to 6.9 μm thick coating comprising three or more TiC _x N _y O _z layers and an α-Al ₂ O ₃ layer deposited on a WC-Co cemented carbide body having a CW ratio of 0.76 to 0.84 and containing 0.52 to 0.64 wt% Cr.

Furthermore, EP 1528125 B1 discloses a cutting tool for machining stainless steel, comprising a tungsten carbide substrate having a binder phase enriched surface area with a thickness of 20 to 40 μm and an average intercept length of 0.9 to 1.3 μm, comprising Ti, Nb and Ta having a Ta to Nb ratio of 1.0 to 3.0 and a Ti to Nb ratio of 0.5 to 1.5, and a coating comprising an alumina layer composed of cylindrical α-Al ₂ O ₃ particles having texture coefficients TC(012)=2.5-3.5 and TC(024)>0.6 x TC(012) and TC (104), TC (110), TC (113), TC (116) <0.3, and an MTCVD Ti(C,N) layer.

The purpose of the present invention is to provide a cutting tool having improved wear resistance and toughness, and in particular, to provide a cutting tool specialized for cutting stainless steel.

Another object of the present invention is to provide a cutting tool with extended life.

The purposes of the present invention are not limited to the purposes mentioned above, and other purposes and advantages of the present invention that are not mentioned can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. In addition, it will be easily understood that the purposes and advantages of the present invention can be realized by the means and combinations thereof described in the specification.

According to a first aspect of the present invention, a cutting tool is provided, comprising: a substrate; and a coating layer on the substrate; wherein the coating layer includes a first layer and a second layer on the first layer, wherein the first layer includes TiCN having a columnar structure, and the second layer includes α-Al ₂ O ₃ , and in the first layer, a ratio of TC (311) to TC (111) (TC (311) / TC (111)) is 1.2 to 1.9 according to the following Equation 1.

[Formula 1]

In the above equation 1, TC(hkl) is the texture coefficient (TC) of each diffraction peak in the (hkl) plane, I(hkl) is the measured integrated intensity of the (hkl) plane of the specimen, I ₀ (hkl) is the standard intensity of the standard powder specimen specified by the Powder Diffraction File (PDF) of the International Center for Diffraction Data (ICDD), and n is the number of reflection planes used to calculate the texture coefficient.

According to a second aspect of the present invention, in the first aspect, the substrate may be composed of a first hard phase, a second hard phase, and a bonding phase, the saturation magnetization of the substrate may be 85 to 92%, and the coercive force of the substrate may be 137 to 159 Oe.

According to a third aspect of the present invention, in the first or second aspect, the substrate may include a bonding layer.

According to a fourth aspect of the present invention, in any one of the first to third aspects, 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)]) may be 1.4 to 3.3.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, in the first layer, among TC (111), TC (200), TC (220), TC (311), and TC (422), TC (311) may be the highest and TC (111) may be the second highest, and in the second layer, among TC (012), TC (104), TC (110), TC (006), TC (113), and TC (116), TC (006) may be the highest and any one of TC (110) and TC (012) may be the second highest.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, in the second layer, the total sum of TC (012), TC (104) and TC (110) may be 2 or more and less than 3.5.

According to a seventh aspect of the present invention, in any one of the first to sixth aspects, in the second layer, the ratio of the sum of TC (012) and TC (104) to TC (110) ([TC (012) + TC (104)] / TC (110)) may be 1 or more and less than 2.5.

According to an eighth aspect of the present invention, in any one of the first to seventh aspects, the coating layer further includes a third layer disposed between the substrate and the first layer, and the third layer may include TiN.

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

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

According to an eleventh aspect of the present invention, a substrate; and a coating layer on the substrate; wherein the coating layer includes a first layer and a second layer on the first layer, wherein the first layer includes TiCN having a columnar structure, and the second layer includes α-Al ₂ O ₃ , and in the second layer, a ratio of the sum of TC(012) and TC(104) to TC(110) ([TC(012)+TC(104)]/TC(110)) according to Equation 1 may be 1 or more and less than 2.5. Here, the eleventh aspect of the present invention may be characterized by at least one or more of the first to tenth aspects; or may be characterized by several embodiments to be described below.

The above-mentioned solution to the problem does not enumerate all the features of the present invention. The various features of the present invention and the advantages and effects thereof can be understood in more detail by referring to the specific description below.

According to one aspect of the present invention, a cutting tool having improved wear resistance and toughness can be implemented.

According to another aspect of the present invention, a cutting tool with an extended life can be realized.

In addition to the effects described above, the specific effects of the present invention are described together with the specific contents for carrying out the invention below. In addition, the effects of the present invention are not limited to the effects mentioned above, and can be easily implemented by the means and combinations thereof described in the specification.

Figure 1 is a cross-sectional view of a cutting tool according to one embodiment of the present invention.
Figure 2 is a cross-sectional view of a cutting tool according to another embodiment of the present invention.

In this specification, singular expressions include plural expressions unless the context clearly indicates otherwise.

The terms "comprise" and/or "comprising", as used herein, specify the presence of stated features, steps, numbers, operations, elements, elements and/or groups thereof, but do not preclude the presence or addition of one or more other features, steps, numbers, operations, elements, elements and/or groups thereof.

In this specification, “At least one of a, b and c” may include a, b or c alone, or a combination of two or more selected from the group consisting of a, b and c.

When several embodiments are described in this specification, each embodiment may be combined unless there is a special description to the contrary. In this case, the effect of the present invention may be defined as including the effect derived from each embodiment and the effect generated when each embodiment is organically combined. For example, even if Embodiments 1 and 2 are described independently in this specification, Embodiments 1 and 2 may be organically combined with each other unless the context clearly indicates otherwise, and the effect of the present invention may include the effect generated when Embodiments 1 and 2 are combined.

The numerical range indicated by the term "to" in this specification represents a numerical range that includes the values described before and after the term as the lower limit and the upper limit, respectively. When multiple numerical values are disclosed as the upper and lower limits of any numerical range, the numerical range disclosed in this specification can be understood as any numerical range that uses any one of the multiple lower limit values and any one of the multiple upper limit values as the lower limit and the upper limit, respectively. For example, when a to b, or c to d are described in the specification, it can be understood that 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 are described.

In this specification, terms such as "about" or "substantially" mean a reasonable amount of variation in the modified term so that the final result is not significantly changed. Such terms may be interpreted to include a variation of at least ±5% or at least ±10%, provided that the variation does not invalidate the meaning of the word.

In this specification, the term "layer" may include cases where the layer is formed not only over the entire region when observing the region where the layer exists, but also over a portion of the region. For example, the surface of the layer may be defined to include a flat shape, a non-flat shape, and a combination thereof; or a continuous shape, a discontinuous shape, and a combination thereof. For example, when another member is formed as a layer directly on top of one member, the coverage of the other member over the surface of the one member 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.

In this specification, the particle diameter may mean the average diameter of each particle observed on a cross-section of a substrate using an electron backscatter diffraction device (EBSD).

In this specification, the XRD (X-ray diffraction) analysis method is an analysis method that diffracts X-rays onto a specimen to represent the internal information of the specimen in a graph, and is an analysis method that can confirm which phase is composed of the specimen by showing peaks at unique angles of various phases. Specifically, the result of the XRD analysis method can be represented as a graph in which the x-axis is 2θ and the y-axis is intensity.

According to one aspect of the present invention, a cutting tool is provided, comprising: a substrate; and a coating layer on the substrate; wherein the coating layer includes a first layer and a second layer on the first layer, wherein the first layer includes TiCN having a columnar structure, and the second layer includes α-Al ₂ O ₃ , and wherein a ratio of TC (311) to TC (111) (TC (311) / TC (111)) in the first layer is 1.2 to 1.9 according to the following Equation 1. According to one aspect of the present invention, the first layer includes TiCN having a columnar structure, the second layer includes α-Al ₂ O ₃ , and when the ratio of TC (311) to TC (111) in the first layer (TC (311) / TC (111)) satisfies 1.2 to 1.9 according to Equation 1 below, a cutting tool having both excellent wear resistance and toughness can be implemented. Specifically, when the ratio of TC (311) to TC (111) (TC (311) / TC (111)) is less than the numerical range, a problem of deterioration in the toughness of the first layer may occur, and when it exceeds the numerical range, a problem of easy crack propagation may occur.

Below, the configuration of the present invention will be described in more detail with reference to the drawings.

Referring to FIG. 1, a cutting tool (100) according to the present invention includes a substrate (10) and a coating layer (20) disposed on the substrate (10).

Description (10)

The substrate (10) according to the present invention can serve as a substrate that helps form a coating layer (20) to be described later, and can also serve to increase the hardness and strength of a cutting tool.

In some embodiments of the present invention, the substrate (10) may be composed of a first hard phase, a second hard phase, and a bonding phase.

1st hard prize

The first hard phase according to the present invention is composed of WC and may be a phase that provides high hardness and strength to the superalloy.

In some embodiments of the present invention, the content of the first hard phase may be 74 to 92 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%, based on the total weight of the substrate. According to some embodiments of the present invention, when the content of the first hard phase satisfies the numerical range, the hardness of the cemented carbide is improved, thereby improving wear resistance, and the toughness of the cemented carbide is improved, thereby improving fracture resistance, whereby the life of the cutting tool can be further extended. In some examples, the content of the WC based on the substrate (the cemented carbide sample) can be analyzed through an EDS (Energy Dispersive X-ray Spectroscopy) analysis method.

In some embodiments of the present invention, the particle size of the WC may be 2 to 7 μm or 3 to 5 μm. According to some embodiments of the present invention, when the particle size of the WC satisfies the numerical range, the chemical resistance of the cemented carbide is maintained at an appropriate level, while the tensile strength and fracture resistance can be sufficiently achieved.

2nd hard prize

The second hard phase according to the present invention may include at least one or more of carbides, nitrides and carbonitrides of metals in groups 4, 5 and 6 of the periodic table to improve the hardness and toughness of the superalloy and extend the life of the cutting tool.

In some examples, at least one metal of Group 4, Group 5 and Group 6 of the periodic table may include at least one 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, and may specifically include at least one cubic compound selected from the group consisting of Ta, Nb, Ti, and W, and more specifically may include all of Ta, Nb, Ti, and W. Specifically, when a cubic compound is used as the second hard phase, the mechanical properties of the cemented carbide are more excellent, so that the life of the cutting tool can be extended.

In some embodiments of the present invention, the second hard phase may include at least one of TaNbC, TiCN, and WTiC. According to some 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 may be more excellent. In some examples, based on the total weight of the substrate, the content of the TaNbC may be 2 to 6 wt%, 2 to 5 wt%, or 3 to 4 wt%, the content of the TiCN may be 0.5 to 3.2 wt%, 1 to 3 wt%, or 1 to 2 wt%, and the content of the WTiC may be 1.5 to 5.6 wt%, 2 to 5 wt%, or 3 to 4 wt%. According to some embodiments of the present invention, when the contents of TaNbC, TiCN and WTiC satisfy the numerical ranges, the toughness of the cemented carbide can be further improved. In some examples, the content of the second hard phase can be analyzed through an EDS analysis method based on a cemented carbide sample.

In some embodiments of the present invention, the weight ratio of Ta, Ti, and Nb may be 2.5 to 3.5:2.5 to 3.5:0.5 to 1.5, and specifically, 3:3:1. In some examples, the weight ratio of Ta, Ti, and Nb may be analyzed using an EDS analysis method based on a cemented carbide sample.

In some embodiments of the present invention, the content of the second hard phase may be 3 to 15 wt%, 4 to 13 wt%, 6 to 12 wt%, 7 to 10 wt%, or 8 to 9 wt% based on the total weight of the substrate. According to some embodiments of the present invention, when the content of the second hard phase satisfies the numerical range, the hardness of the cemented carbide is improved, thereby improving wear resistance, and the toughness of the cemented carbide is improved, thereby improving fracture resistance, whereby the life of the cutting tool can be further extended.

Combined

The bonding agent according to the present invention may include at least one of Co and Ni to improve the toughness and hardness of the superalloy.

In some embodiments of the present invention, the content of the bonding phase may be 5 to 11 wt%, 6 to 10 wt%, 7 to 9 wt%, or 7 to 8 wt% based on the total weight of the substrate. According to some embodiments of the present invention, when the content of the bonding phase satisfies the numerical range, the wear resistance and fracture resistance of the cemented carbide may be balancedly improved, thereby extending the life of the cutting tool. In some examples, the content of the bonding phase may be analyzed using an EDS analysis method based on a cemented carbide sample.

Parameters of the description

Meanwhile, the saturation magnetization rate of the material (e.g., superalloy) can be calculated by the following mathematical expression 1.

[Mathematical formula 1]

Saturation susceptibility of the substrate (%) = {[M1(emu)]/[M2(emu/g)ХM3(g)]}

In the above mathematical expression 1, M1 is the saturation magnetization (emu) of the substrate, M2 is the theoretical saturation magnetization of Co (emu/g), and M3 is the content of Co in the substrate (g). That is, the saturation magnetization (%) of the substrate means the ratio of the saturation magnetization (emu) of the substrate to the theoretical saturation magnetization (emu) of Co included in the substrate. In some examples, the saturation magnetization (emu) of the substrate can be measured using a known magnetic property measuring device. In addition, the theoretical saturation magnetization of Co may be a known value. The saturation magnetization is generally determined by the Co content and the carbon content of the cemented carbide, and controlling the saturation magnetization within an appropriate range may mean regulating the carbon content relative to the content of the constituent elements so as not to include an η phase or free carbon in the structure.

In some 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 some embodiments of the present invention, since the saturation magnetization of the substrate satisfies the numerical range, the carbon content can be adjusted high within a range in which the η phase or glassy carbon is not formed, thereby further enhancing the toughness of the cemented carbide.

The magnetic force is usually controlled by the grain size of the WC hard phase and the thickness of the bonding phase. The smaller the WC grain size and the larger the thickness of the bonding phase, the higher the magnetic force. For example, if the magnetic force is high, the hardness of the cemented carbide increases, but the toughness may decrease.

In some embodiments of the present invention, the coercive force of the substrate can 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 some embodiments of the present invention, when the coercive force and the saturation magnetization of the substrate satisfy the numerical ranges, the thickness of the bonding phase bonding between the WC particles is adjusted to an appropriate level, and the content of the metal component or carbon constituting the hard phase dissolved in the bonding phase is adjusted to an appropriate level, so that a cemented carbide substrate having high toughness and hardness can be implemented.

Additional Components

In some embodiments of the present invention, the substrate (10) may include a bonding layer (not shown) that improves the toughness of the substrate surface and reduces the difference in thermal expansion coefficient with the coating layer to be described later, thereby alleviating thermal cracks in the coating layer.

In some examples, the bonding 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 some examples, when the thickness of the bonding layer satisfies the numerical range, the toughness of the substrate surface can be improved while sufficiently alleviating thermal cracks of the coating layer, and the wear resistance of the substrate can be maintained at an appropriate level.

In some examples, the bonding phase enrichment layer may include the bonding phase described above without including the second hard phase described above. Specifically, the bonding phase enrichment layer may contain 1.2 to 1.7 times more bonding phase than the remaining portion of the substrate that is not the bonding phase enrichment layer.

In some embodiments of the present invention, the substrate (10) may have a cutting edge formed on a ridge where the inclined surface and the clearance surface intersect, a relief surface in contact with the inclined surface, and a cutting edge involved in cutting.

Coating layer (20)

The coating layer (20) according to the present invention includes a first layer (21) and a second layer (22) on the first layer (21).

1st floor

The first layer (21) according to the present invention includes TiCN having a columnar structure. At this time, the columnar structure may mean a structure having a pillar-shaped crystal in the thickness direction of the first layer (21). Specifically, since the first layer (21) includes TiCN having a columnar structure, it is possible to control the tissue orientation of the second layer (alpha-alumina) described below, while simultaneously implementing adhesion to the second layer and its own defect resistance and wear resistance.

In some examples, the first layer (21) may be formed by a medium temperature-chemical vapor deposition (MT-CVD) process. Here, the MT-CVD process temperature may be performed at a temperature of 800 to 950°C. If the first layer is formed by a high temperature CVD (HT-CVD) process performed at a temperature of 1000°C or higher, not only may the substrate be damaged by heating during film formation, but an equiaxed structure may be formed in the first layer, making it difficult to control the structure orientation of the second layer (alpha-alumina).

According to some embodiments of the present invention, among TC (111), TC (200), TC (220), TC (311) and TC (422) in the first layer, TC (311) may be the highest and TC (111) may be the second highest.

In the first layer (21) according to the present invention, the ratio of TC (311) to TC (111) (TC (311)/TC (111)) according to the above formula 1 is 1.2 to 1.9, and specifically, 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 less than the above numerical range, a problem of deterioration in the toughness of the first layer may occur, and if it exceeds the above numerical range, a problem of easy crack propagation may occur.

[Formula 1]

In the above Equation 1, TC(hkl) is the texture coefficient (TC) of each diffraction peak in the (hkl) plane, I(hkl) is the measured integrated intensity of the (hkl) plane of the specimen, I ₀ (hkl) is the standard intensity of the standard powder specimen specified by the PDF (Powder Diffraction File) of the ICDD (International Center for Diffraction Data), and n is the number of reflecting surfaces used to calculate the texture coefficient. For example, for the first layer, the standard powder specimen may be CNMG120408, and the PDF (Powder Diffraction File) card number of the ICDD (International Center for Diffraction Data) may be 42-1489.

According to some embodiments of the present invention, among TC(111), TC(200), TC(220), TC(311), and TC(422) in the first layer, 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 (311) plane grown first promotes the (006) orientation of the second layer (α-Al ₂ O ₃ ), so that a sufficient texture coefficient can be achieved despite a relatively thin film thickness, and the fracture resistance of the first layer can be improved. In addition, since the (111) plane has a dense structure, the hardness of the first layer can be increased and the adhesion with the second layer can be enhanced, so as to effectively prevent the occurrence of peeling.

According to some embodiments of the present invention, the texture coefficients TC(200), TC(220) and TC(422) of the (200) plane, (220) plane and (422) plane, excluding the (311) plane and the (111) plane, can all be less than 1.1.

In some embodiments of the present invention, the TC (311) of the first layer (21) may be greater than 1.5 and less than 3.0, 1.8 to 2.8, 1.9 to 2.5, or 1.9 to 2.3.

In some examples, the thickness of the first layer (21) may be specifically 1 to 5 μm, 2 to 5 μm, 2 to 4 μm, or 3 to 4 μm.

2nd floor

The second layer (22) according to the present invention can improve the hardness and toughness of the coating layer.

The second layer (22) according to the present invention includes α-Al ₂ O ₃ . Specifically, by including alpha-alumina in the second layer (22), the effects of excellent hardness and wear resistance at high temperatures compared to other crystal structures can be realized.

In some examples, the second layer (22) may include α-Al ₂ O ₃ having a columnar structure. Specifically, by including alpha-alumina having a columnar structure as the second layer (22), the phenomenon of chipping of the coating layer due to interaction with the tissue orientation of the first layer can be effectively suppressed, while at the same time, the effect of maintaining thermal conductivity can be achieved.

Meanwhile, the texture coefficient can also be measured in the second layer (22) according to the above equation 1. At this time, the standard powder specimen is CNMG120408, and the card number of the standard powder specimen specified by the PDF (Powder Diffraction File) of the ICDD (International Center for Diffraction Data) can be 42-1212.

In some 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) may be the highest, and either TC(110) or TC(012) may be the second highest.

In some 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)]) can be 1.4 to 3.3, 1.5 to 3.0, 1.8 to 3.0, 2.0 to 3.0 or 2.07 to 2.87. According to some 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)]) satisfies the numerical range, thereby effectively suppressing the occurrence of a peeling (chipping) phenomenon of the coating layer due to interaction with the tissue orientation of the first layer, while achieving an effect of maintaining thermal conductivity.

According to some embodiments of the present invention, the texture coefficients TC(113) and TC(116) of the (113) and (116) planes, excluding the (006) plane, the (012) plane, the (104) plane, and the (110) plane, can all be less than 0.4.

In some embodiments of the present invention, in the second layer, the total sum of TC (012), TC (104), and TC (110) may 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 some embodiments of the present invention, when the total sum of TC (012), TC (104), and TC (110) satisfies the numerical range, the phenomenon of peeling off (chipping) of the coating layer due to interaction with the tissue orientation of the first layer can be effectively suppressed, while achieving the effect of maintaining thermal conductivity.

In some embodiments of the present invention, the ratio of the sum of TC (012) and TC (104) to TC (110) in the second layer ([TC (012) + TC (104)] / TC (110)) may 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 some embodiments of the present invention, since the ratio of the sum of TC (012) and TC (104) to TC (110) ([TC (012) + TC (104)] / TC (110)) satisfies the numerical range, the phenomenon of peeling off (chipping) of the coating layer due to interaction with the tissue orientation of the first layer can be effectively suppressed, while achieving the effect of maintaining thermal conductivity.

In some examples, the thickness of the second layer (22) may be specifically 0.5 to 4.0 μm, 1.0 to 3.0 μm, or 1.5 to 2.5 μm.

3rd floor

In some embodiments of the present invention, the coating layer (20) may further include a third layer (23) disposed between the substrate (10) and the first layer (21).

The third layer (23) according to the present invention can improve the adhesion of the coating layer to the surface of the substrate and effectively prevent the components of the substrate from diffusing into the coating layer.

Specifically, the third layer (23) may include TiN.

In some examples, the thickness of the third layer (23) is not particularly limited and may be specifically 0.1 to 2.0 ㎛, 0.2 to 1.5 ㎛, 0.3 to 1.2 ㎛, 0.4 to 1.1 ㎛, or 0.5 to 1.0 ㎛.

4th floor

In some embodiments of the present invention, the coating layer (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) to assist in bonding the first layer (21) and the second layer (22).

In some 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, by including at least one selected from the group consisting of TiC, TiCN, TiCNO, TiCO, and TiNO in the fourth layer (24), the bonding between the first layer (21) and the second layer (22) is further improved, and the bonding strength between the layers forming the coating layer can be further improved.

In some examples, the fourth layer (24) may include TiCNO that can grow into a columnar structure. Specifically, the fourth layer (24) may include TiCNO having the columnar structure, thereby not interfering with the tissue orientation control effect of the second layer.

In some examples, the fourth layer (24) may not include TiCN having an equiaxed structure. If the fourth layer includes TiCN having an equiaxed structure, a problem of interfering with the tissue orientation control of the second layer (22) described above may occur.

In some examples, the thickness of the fourth layer (24) may 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 0.6 μm.

5th floor

Fig. 2 is a cross-sectional view of a cutting tool according to another embodiment of the present invention. Parts described above and repeated descriptions are briefly described or omitted.

Referring to FIG. 2, in some embodiments of the present invention, the coating layer (20) may further include a fifth layer (25) on the second layer (22), and specifically, may further include a fifth layer (25) disposed directly above the second layer (22). In some examples, the fifth layer (25) may be the uppermost layer or the outermost layer of the coating layer (20).

The fifth layer (25) according to the present invention can effectively prevent the wear resistance of the coating layer from deteriorating and function as a wear recognition layer.

In some examples, the fifth layer (25) may include, without limitation, at least one of TiC, TiN, and TiCN.

In some examples, the thickness of the fifth layer (25) is not particularly limited and may be specifically 0.1 to 3.0 μm.

Relationships between components

In some embodiments of the present invention, the substrate (10) may have a slope involved in cutting, a clearance surface in contact with the slope surface, and a cutting edge portion formed on a ridge where the slope surface and the clearance surface intersect. In this case, the coating layer (20) of some embodiments may be formed on at least one of the slope surface, the clearance surface, and the cutting edge portion.

For example, the coating layer (20) may be partially formed on at least one of the inclined surface and the relief surface. At this time, the coating layer (20) on the cutting edge may be processed so that the second layer (22) is removed through post-processing such as blasting or buffing, and the first layer (21) becomes the outermost layer. Due to the characteristics of the first layer (21) having high toughness, the efficiency of cutting processing may be improved by directly contacting the workpiece.

Hereinafter, embodiments of the present invention will be described in detail so that a person having ordinary skill in the art to which the present invention pertains can easily implement the present invention, but this is only an example, and the scope of the rights of the present invention is not limited by the following contents.

[Manufacturing Example: Manufacturing of Cutting Tools]

<Example 1>

Preparation steps for the article:

A superalloy substrate was prepared, which was composed of 83.7 wt% of the first hard phase (WC), 7.5 wt% of the bonding phase (Co), and 4 wt% of the second hard phase (TaNbC, 1.2 wt% of TiCN, and 3.6 wt%). At this time, the superalloy substrate had a WC particle size of 4 ㎛, and according to the following mathematical expression 1, a saturation magnetization of 89.75% and a coercive force of 145.1 Oe.

[Mathematical formula 1]

Saturation susceptibility of the substrate (%) = {[M1(emu)]/[M2(emu/g)ХM3(g)]}

In the above mathematical expression 1, M1 is the saturation magnetization (emu) of the substrate, M2 is the theoretical saturation magnetization (emu/g) of Co, and M3 is the content (g) of Co in the substrate. That is, the saturation magnetization (%) of the substrate means the ratio of the saturation magnetization (emu) of the substrate to the theoretical saturation magnetization (emu) of Co included in the substrate. In some examples, the saturation magnetization (emu) of the substrate can be measured using a known magnetic property measuring device. In addition, the theoretical saturation magnetization of Co can be a known value.

Step of forming a coating layer on the above substrate:

A coating layer was formed on the above substrate by deposition under the deposition conditions described in Table 1 below. Specifically, a third layer (TiN, thickness = 0.5 μm), a first layer (MT-TiCN, thickness = 3.6 μm), a fourth layer (TiCNO, thickness = 0.4 μm), and a second layer (α-Al ₂ O _3, thickness = 2.4 μm) were sequentially deposited on the surface of the substrate to manufacture an insert having the model number CNMG120408.

division Reaction gas [vol%] Pressure [mbar] Temperature [ºC] 3rd floor
(TiN) TiCl ₄ : 1.3%, N ₂ : 36%, H ₂ : balance 200 915 1st floor
(MT-TiCN) beginning TiCl ₄ : 3%, CH ₃ CN: 0.7%, H ₂ : balance 70 850 Mid term TiCl ₄ : 2.5%, CH ₃ CN: 0.85%, N ₂ : 18%, H ₂ : balance 55 850 last period TiCl ₄ : 2.5%, CH ₃ CN: 0.6%, N ₂ : 15%, HCl: 0.4%, H ₂ : balance 55 950 4th floor
(TiCNO) TiCl ₄ : 3.3%, CH ₃ CN: 1.2%, _CO2 : 3.6%, CO: 4%, _H2 : balance 55 1000 Second layer (α-Al ₂ O ₃ ) beginning AlCl ₃ : 3.4%, HCl: 1.7%, CO ₂ : 3.6%, H ₂ : balance 65 1000 last period AlCl ₃ : 3.4%, HCl: 1.7%, H ₂ S: 0.3%, _CO2 : 3.6%, _H2 : balance 65 1000

<Examples 2 to 5>

Cutting tools were manufactured using the same method as Example 1, but Examples 2 to 5 were manufactured in which the thickness deviation of the coating layer was within a maximum of 1 ㎛.

<Comparative examples 1 and 2: Preparation of commercial products>

Commercial comparative examples 1 and 2 having the characteristics shown in Table 2 below were prepared.

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

Table 2 below shows the texture coefficients (TC) for each diffraction peak of the first layer (MT-TiCN) in the cutting tools of the examples and comparative examples, and Table 4 below shows the texture coefficients for each diffraction peak of the second layer (α-Al ₂ O ₃ ).

The texture coefficient can be calculated as the value described in Equation 2 below based on the XRD (X-ray diffraction) analysis method. Specifically, for the XRD (X-ray diffraction) analysis, an X-ray diffraction equipment (model name: X'pert) from Malvern Panalytical was used, and a detector equipped with Bragg Brentano HD (hereinafter referred to as 'BBHD') and Pixel 3D was used. Copper (Cu) was used as the XRD electrode material, and a Cu-Kα wavelength of 45 kV and 40 mA was used. The BBHD was equipped with a 1/2° antiscatter slit and a 1/8° divergence, and a 1/2 solar slit was connected to the detector and used. The measurement was performed for 2θ of 20° to 145° using the θ-2θ method.

[Formula 1]

In the above equation 1, TC(hkl) is the texture coefficient of each diffraction peak in the (hkl) plane, I(hkl) is the measured integrated intensity of the (hkl) plane of the specimen, I ₀ (hkl) is the standard intensity of the standard powder specimen specified by the PDF (Powder Diffraction File) of the ICDD (International Center for Diffraction Data), and n is the number of reflection planes used to calculate the texture coefficient. At this time, 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-Al ₂ O ₃ ).

division
(1st floor) TC(111) TC(200) TC(220) TC(311) TC(422) TC(311)/TC(111) Example 1 1.22 0.08 1.07 1.90 0.71 1.56 Example 2 1.33 0.09 0.71 2.08 0.77 1.56 Example 3 1.49 0.16 0.57 2.04 0.75 1.37 Example 4 1.18 0.14 0.69 2.23 0.76 1.89 Example 5 1.32 0.18 0.97 1.96 0.55 1.48 Comparative Example 1 0.76 0.24 0.59 2.08 1.33 2.74 Comparative Example 2 0.23 0.26 1.33 2.32 0.84 10.09 TC(311)/TC(111) is the value rounded to the second decimal place.

Referring to Table 2 above, with respect to the first layer, Examples 1 to 5 confirmed that the ratio of TC (311) to TC (111) (TC (311)/TC (111)) satisfies 1.2 to 1.9. On the other hand, Comparative Examples 1 and 2 confirmed that the ratio of TC (311) to TC (111) (TC (311)/TC (111)) does not satisfy the above numerical range.

In addition, Examples 1 to 5 showed that among TC (111), TC (200), TC (220), TC (311), and TC (422), TC (311) was the highest and TC (111) was the second highest.

On the other hand, in Comparative Examples 1 and 2, TC (311) showed the highest value among TC (111), TC (200), TC (220), TC (311), and TC (422), but TC (111) did not show the second highest characteristic.

division
(2nd floor) TC(012) TC(104) TC(110) TC(006) TC(113) TC(116) TC(006)/
TC(012 or 110) TC(012)+TC(104)+TC(110) [TC(012)+TC(104)]/TC(110) Example 1 1.17 0.54 0.69 3.01 0.28 0.28 2.57 2.40 2.48 Example 2 1.02 0.49 1.31 2.71 0.26 0.18 2.07 2.82 1.15 Example 3 1.19 0.54 0.70 3.06 0.20 0.28 2.57 2.43 2.47 Example 4 0.85 0.44 1.28 3.01 0.23 0.15 2.35 2.57 1.01 Example 5 0.94 0.86 0.92 2.70 0.24 0.30 2.87 2.72 1.96 Comparative Example 1 0.05 0.04 0.49 5.06 0.30 0.03 10.33 0.58 0.18 Comparative Example 2 1.02 1.19 0.59 2.09 0.59 0.52 2.05 2.80 3.75 TC(012 or 110) refers to the set organization coefficient with the higher value between TC(012) and TC(110).
[TC(012)+TC(104)]/TC(110) is the value rounded to the second decimal place.

Referring to Table 3 above, it was confirmed that the Examples and Comparative Examples commonly include α-Al ₂ O ₃ grown primarily on the (006) plane. However, unlike Comparative Example 1 in which all planes other than the (006) plane exhibit low texture coefficients of less than 0.5, Examples 1 to 5 exhibit a total sum of TC (012), TC (104), and TC (110) of 2 or more and less than 3.5, and among them, one of TC (012) and TC (110) is the second highest, and the ratio of TC (006) to the higher value of TC (012) and TC (110) is 1.4 to 3.3.

In addition, Examples 1 to 5 satisfy that the sum ratio of TC (012) and TC (104) to TC (110) ([TC (012) + TC (104)] / TC (110)) is 1 or more and less than 2.5.

Meanwhile, in Comparative Example 2, unlike Examples 1 to 5, TC (104) was the second highest, and the sum ratio of TC (012) and TC (104) to TC (110) ([TC (012) + TC (104)] / TC (110)) was 2.8, which is 2.5 or higher.

[Experimental Example 2: Performance Evaluation of Cutting Tools]

The wear resistance and toughness of the cutting tools of the examples and comparative examples were measured under the analysis conditions described in Table 4 below, and the results are shown in Table 5 below.

division My wear test personality test Cutting material SUS304 S45C*
(Create a break condition by drilling multiple holes in the workpiece) Speed (m/min or rpm) 210 m/min (cutting speed) 1000 RPM Feed (mm/rev) 0.28 0.05 or higher (increases by 0.02 mm/rev as processing progresses) Incision (mm) 2 1.5 End point When cutting tool wear reaches 250 ㎛ In case of cutting tool breakage

division My wear evaluation
(Time taken until end) Personality assessment
(Time taken until end) Example 1 20 minutes 54 seconds 8 minutes 21 seconds Example 2 18 minutes 58 seconds 7 minutes 55 seconds Example 3 24 minutes 37 seconds 7 minutes 54 seconds Example 4 16 minutes 45 seconds 8 minutes 20 seconds Example 5 19 minutes 58 seconds 8 minutes 18 seconds Comparative Example 1 8 minutes 29 seconds 3 minutes 48 seconds Comparative Example 2 3 minutes 00 seconds 7 minutes 32 seconds

In the above Table 5, Examples 1 to 5, in which the ratio of TC (311) to TC (111) of the first layer (TC (311) / TC (111)) satisfies 1.2 to 1.9, were confirmed to exhibit excellent wear resistance and fracture resistance compared to Comparative Examples 1 and 2, which did not satisfy the above numerical range. Specifically, Comparative Example 1 had poor wear resistance and toughness, and Comparative Example 2 had excellent toughness but very poor wear resistance, showing unbalanced performance.

The features described in the above-described embodiment may be combined with other embodiments unless the contrary description is explicitly stated. In addition, although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention.

10: Description
20: Coating layer
21: 1st floor
22: 2nd floor
23: 3rd floor
24: 4th floor
25: 5th floor
100: Cutting tools

Claims (10)

Description; and
Including the coating layer as described above;
The above coating layer is,
comprising 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-Al ₂ O ₃ ,
On the first floor above,
According to the following equation 1, the ratio of TC(311) to TC(111) (TC(311)/TC(111)) is 1.2 to 1.9, and TC(422) is less than 1.1.
Cutting tools:
[Formula 1]

In the above equation 1,
TC(hkl) is the texture coefficient (TC) of each diffraction peak in the (hkl) plane,
I(hkl) is the measured integrated intensity of the (hkl) plane of the specimen,
I ₀ (hkl) is the standard strength of the standard powder specimen specified by the Powder Diffraction File (PDF) of the International Center for Diffraction Data (ICDD),
n is the number of reflecting surfaces used to calculate the texture coefficient. In the first paragraph,
The above description is composed of a first hard phase, a second hard phase and a bonding phase,
The saturation magnetization rate of the above description is calculated according to the following mathematical formula 1 and is 85 to 92%.
The magnetic force of the above-mentioned material is 137 to 159 Oe.
Cutting tools:
[Mathematical Formula 1]
Saturation susceptibility of the substrate (%) = {[M1(emu)]/[M2(emu/g)×M3(g)]}
In the above mathematical expression 1, M1 is the saturation magnetization (emu) of the substrate, M2 is the saturation magnetization of Co (emu/g), and M3 is the content of Co in the substrate (g). In the first paragraph,
The above description includes a bonding layer,
Cutting tools. In the first paragraph,
In the second floor above,
The ratio of TC(006) to the higher value among TC(012) and TC(110) (TC(006)/[the higher value among TC(012) and TC(110)]) is 1.4 to 3.3,
Cutting tools. In the first paragraph,
On the first floor above,
Among TC(111), TC(200), TC(220), TC(311) and TC(422), TC(311) is the highest, TC(111) is the second highest,
On the second floor above,
Among TC(012), TC(104), TC(110), TC(006), TC(113), and TC(116), TC(006) is the highest, and either TC(110) or TC(012) is the second highest.
Cutting tools. In the first paragraph,
In the second floor above,
The total sum of TC(012), TC(104) and TC(110) is 2 or more and less than 3.5,
Cutting tools. In the first paragraph,
In the second floor above,
The sum ratio of TC(012) and TC(104) to TC(110) ([TC(012)+TC(104)]/TC(110)) is 1 or more and less than 2.5,
Cutting tools. In the first paragraph,
The above coating layer is,
Further comprising a third layer disposed between the above-described substrate and the first layer;
The third layer comprises TiN,
Cutting tools. In the first paragraph,
The above coating layer is,
Further comprising a fourth layer disposed between the first layer and the second layer;
The above fourth layer is,
Containing at least one selected from the group consisting of TiC, TiCN, TiCNO, TiCO, and TiNO;
Cutting tools. In the first paragraph,
The above coating layer is,
Further comprising a fifth layer on the second layer;
The above fifth layer is,
Comprising at least one of TiC, TiN, and TiCN,
Cutting tools.