JP2010082740A - Surface coated cutting tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface coated cutting tool capable of cutting a material to be cut having a wide range of hardness and strength and reducing replacement frequency of the surface coated cutting tool. <P>SOLUTION: The surface coated cutting tool has a base material and a coating formed on the base material. The coating includes at least one layer of coating layers. At least the one layer is a Zr-contained coating layer containing Zr and further the surface coated cutting tool has two or more cutting blade parts. The Zr content of the coating in a first cutting blade as one of the cutting blade parts is different from that in at least one cutting blade of other cutting blade parts except the first cutting blade. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a surface-coated cutting tool that can cut a work material having a wide range of hardness and strength and can reduce the number of times of replacement of the surface-coated cutting tool.

  As a market need in recent years, it is a cutting tool that can cut a work material of all hardness with one cutting tool, and even if it is used for a long period of time, the wear of the surface-coated cutting tool is small, and the surface coating The appearance of a surface-coated cutting tool that can reduce the number of times of exchanging the cutting tool is desired.

  In general, cemented carbides and cermets used as base materials for cutting tools including surface-coated cutting tools are required to have excellent properties such as heat crack resistance, oxidation resistance, high temperature hardness, fracture toughness, In order to improve the thermal crack resistance and fracture toughness, cemented carbides and cermets used for the base materials of current cutting tools have been devised by various researchers.

  A surface-coated cutting tool using a base material manufactured by a method of pressing and sintering a powder such as cemented carbide or cermet has a plurality of coating layers on the base material, and the coating layer The heat crack resistance and fracture toughness can be adjusted by changing the crystal structure of the hard material contained in the material or changing the content of the hard material contained in the coating layer.

  Attempts have conventionally been made to adjust the thermal crack resistance and fracture toughness for each site by appropriately changing the crystal structure and content of the hard material contained in these coating layers. For example, Japanese Patent Application Laid-Open No. 2003-82432 Japanese Patent Publication (Patent Document 1) proposes a technique for changing the amount of a binder phase of a hard material coating layer depending on a part. According to the surface-coated cutting tool of the present technology, a portion where the binder phase of the hard material coating layer is low has thermal crack resistance, and a portion where the binder phase of the hard material coating layer is high has fracture toughness. It is excellent in that it can be applied to various work materials having various strengths and hardnesses.

  However, the range of hardness and strength of the work material that can be handled by the surface-coated cutting tool is not sufficient, and the appearance of a surface-coated cutting tool that can handle a wider range of hardness and strength has been desired.

  Under such circumstances, as another attempt to change the characteristics of thermal crack resistance and fracture toughness depending on the part of the surface-coated cutting tool, Japanese Patent Application Laid-Open No. 2006-236447 (Patent Document 2) describes a hard material coating layer depending on the part. Surface-coated cutting tools that vary the thickness have been proposed. According to the surface-coated cutting tool according to the present technology, the hard material coating layer having a thin thickness has heat crack resistance, and the hard material coating layer having a thick thickness has fracture toughness. It was possible to cope with work materials with high strength.

  However, if this surface-coated cutting tool is used for a long period of time, wear reduction occurs in the hard material coating layer. As a result, there is a new problem that the frequency of replacing the surface-coated cutting tool is increased.

Based on the above, the emergence of surface-coated cutting tools that can cut work materials with a wide range of hardness and strength and that can reduce the number of replacements of surface-coated cutting tools. Is desired.
JP 2003-82432 A JP 2006-236447 A

  The present invention has been made in view of the current situation as described above. The object of the present invention is to cut a work material having a wide range of hardness and strength, and to replace the surface-coated cutting tool. It is an object of the present invention to provide a surface-coated cutting tool capable of reducing the amount of the cutting.

  As a result of various studies to solve the above problems, the inventor has an ideal state for cutting a wide range of work materials having different hardness and strength depending on the part of the surface-coated cutting tool. It is possible to change the Zr content depending on the part involved in the cutting of the surface-coated cutting tool by paying attention to the distribution of Zr contained in the coating by further studying based on this knowledge. The present invention has finally been completed by obtaining further knowledge that it is most effective for the above-mentioned purpose, and by further intensive studies under this knowledge.

  That is, the surface-coated cutting tool of the present invention is a surface-coated cutting tool comprising a substrate and a coating formed on the substrate, and the coating includes at least one coating layer, and the coating layer At least one layer is a Zr-containing coating layer containing Zr, and the surface-coated cutting tool further has two or more cutting edge portions, and the first cutting edge portion is a first cutting edge portion of the cutting edge portions. The Zr content of the coating in one cutting edge is different from the Zr content of the coating in at least one of the other cutting edges except the first cutting edge.

Moreover, in the surface-coated cutting tool of the present invention, the Zr content of the coating is X ₁ among the Zr contents of the coating in any one of the cutting edges, and the Zr content that maximizes the Zr content is X ₁ , When the Zr content that minimizes the Zr content is X ₂ and the average value of the Zr content of the coating in all the cutting edges is X _ave , X ₁ , X _2, and X _ave are represented by the following formula (I ) Is preferably satisfied.

(X ₁ −X ₂ ) / X _ave ≧ 0.04 (I)
Further, the surface-coated cutting tool of the present invention has two rake faces, each of the rake faces has at least two diagonal lines, and both ends of the diagonal lines are included in the cutting edge portion. Of the rake faces, the rake face having a larger area is defined as a first rake face, the rake face having a smaller area is defined as a second rake face, and one of the diagonal lines of the first rake face is selected. The average value of the Zr content of the coating at the two cutting edges located at both ends of the first diagonal line, which is a diagonal line, is Y _1, and is a diagonal line parallel to the first diagonal line among the diagonal lines of the second rake face When the average value of the Zr content of the coating at the two cutting edges located at both ends of the second diagonal line is Y ₂ and the average value of the Zr content of the coating at all the cutting edges is Y _ave , Y ₁ , Y ₂ and Y _ave preferably satisfy the following formula (II).

(Y ₁ −Y ₂ ) / Y _ave ≧ 0.04 (II)
The surface-coated cutting tool of the present invention has at least two flank surfaces, and one flank surface of the flank surfaces has one ridge that intersects at least one flank surface among the other flank surfaces. There are a plurality of shared ridges in the surface-coated cutting tool, and both ends of the shared ridge are included in the above-mentioned cutting edge portion, and any one of the shared ridges The average value Z ₁ of the Zr content of the coating at the two cutting edges located at both ends of the first shared ridge is the Zr content of the coating at the two cutting edges located at both ends of the other shared ridge. becomes maximum among the average values, among the shared edges, any one mean value Z ₂ of Zr content of the film in the second cutting edge portions located at both ends of the second shared edge is shared edges of the other Among the average values of the Zr content of the coating at the two cutting edges located at both ends of the common ridge It becomes minimum, when the average value of the Zr content of the film in all the cutting edge portion and the Z _ave, it is preferable that Z _1, Z ₂ and Z _ave satisfy the following formula (III).

_{(Z 1 -Z 2) / Z} ave ≧ 0.04 ··· (III)
It is preferable that the first shared edge described above intersects with any one of the diagonal lines on the first rake face, and the diagonal line also intersects with the second shared edge described above.

  If the surface-coated cutting tool of the present invention is a negative tip, the effect of the present invention becomes remarkable.

  Here, the coating preferably includes one or both of an aluminum oxide layer mainly containing aluminum oxide and a titanium compound layer mainly containing a titanium compound.

  The Zr-containing coating layer is preferably one or both of the aluminum oxide layer and the titanium compound layer.

  Further, the coating includes at least one hard compound layer in addition to the Zr-containing coating layer, and the hard compound layer is composed of IVa group element, Va group element, VIa group element, Al, Si in the periodic table. And a layer mainly comprising a compound consisting of at least one element selected from the group consisting of boron and at least one element selected from the group consisting of carbon, nitrogen, oxygen and boron, More preferably, the layer mainly contains a compound composed of at least one element selected from the group consisting of carbon, nitrogen, oxygen and boron.

  According to the present invention, it is possible to provide a surface-coated cutting tool that can cut a work material having a wide range of hardness and strength and can reduce the number of replacements of the surface-coated cutting tool.

  Hereinafter, each part of the surface-coated cutting tool of the present invention will be described in more detail. In the following description, the description is made with reference to the drawings. In the drawings of the present invention, the same reference numerals denote the same or corresponding parts. Each drawing is a schematic diagram for explanation only, and the size ratio between the surface-coated cutting tool body and the cutting edge portion may be different from the actual size.

<Surface coated cutting tool>
The surface-coated cutting tool of the present invention includes a base material and a coating film formed on the base material, the coating film includes at least one coating layer, and further includes two or more cutting edge portions. is there. The surface-coated cutting tool of the present invention having such a configuration has a shape in which the upper surface and a cross section parallel to the upper surface are polygonal or circular (preferably, diamond, square, triangle, rectangle, round, etc.). .

  FIG. 1 shows a schematic perspective view of a preferred example of the surface-coated cutting tool of the present invention. This surface-coated cutting tool 101 has a rake face that comes into contact with chips of the work material during cutting and a flank face that comes into contact with the work material itself. In FIG. 1, two rhombus surfaces are usually rake surfaces 102 a and 102 b, and four surfaces other than the rhombus surfaces are flank surfaces 103.

  Further, a ridge where one flank of the flank 103 and the other one flank intersect is called a shared ridge 104, and a ridge where one flank and one rake face intersect is called a cutting edge ridge line 106. The shared ridge 104 and the cutting edge ridge line 106 may each be chamfered. Even if chamfering is performed in this way and no clear edge is formed, in the present invention, it is referred to as a cutting edge edge line or a shared edge. Further, such a surface-coated cutting tool 101 may be provided with a hole penetrating to the lower surface in the center of the upper surface.

  Further, the surface-coated cutting tool of the present invention may have a concavo-convex shape called a chip breaker formed on the rake face, and the shape of the surface-coated cutting tool may be either a negative tip shape or a positive tip shape. Although it is possible to take a shape, it is preferable to use a negative tip having a large number of cutting edges per tip because it can be used on both sides when either shape may be used.

<Cutting edge>
In the surface-coated cutting tool 101 of the present invention, the “cutting edge portion” refers to a corner portion of the surface-coated cutting tool 101 that is involved in cutting. In the present invention, the “cutting edge portion” includes one or both of the corner portion of the substrate and the corner portion of the coating.

  For example, in the surface-coated cutting tool 101 shown in FIG. 1, the cutting edge portion indicates a hatched portion of the surface-coated cutting tool 101. In FIG. 1, the hatched portion is attached to only one cutting edge portion, but all eight corner portions at the apex of the surface-coated cutting tool 101 become cutting edge portions 107 (for convenience, other cutting edge portions 107). The seven cutting edges are not shaded).

Here, the “corner portion” is a predetermined length (t) extending in the direction of one cutting edge ridge line 106a from the intersection where the two cutting edge ridge lines 106a, 106b and one common ridge 104 intersect as shown in FIG. say ₁ mm), a predetermined length extending in the direction of the other cutting edge 106b and (t ₂ mm), a portion of the quadrangular prism to the shared predetermined from crest 104 length (hmm) and the respective sides. In addition, each intersection point as used in the present invention may be chamfered, and even if chamfering is performed in this way, it is called an intersection point.

Here, it is difficult to specify the length (t ₁ mm), (t ₂ mm), and (hmm) of the cutting edge portion by specific numerical values. This is because the range of parts involved in cutting differs depending on the shape of the surface-coated cutting tool, the type of work material, and the like. Therefore, when this cutting edge portion is defined, it is most preferable to set it as the “part relating to cutting” as described above, but this length (t ₁ mm), (t ₂ mm) and (hmm) ), It can be 0.5% or more and 40% or less of the length of the shared ridge and the edge of the cutting edge (this length is always the same length at each ridge due to the polygonal shape) is not). In addition, said "part which is concerned in cutting" means the part which contacts a work material, and the part which does not contact a work material but contacts a chip.

<Coating>
The “film” formed on the base material in the surface-coated cutting tool 101 of the present invention is a film that covers a part or all of the base material, and includes at least one coating layer. The coating of the surface-coated cutting tool 101 of the present invention is characterized by containing Zr, and by containing Zr in the coating, both the toughness and the wear resistance of the surface-coated cutting tool are made higher than ever. be able to.

  The total thickness of such a coating (when two or more coating layers are included, the total thickness of each coating layer) is preferably 0.1 to 30 μm, more preferably 0.5 to 25 μm, even more preferably. Is 1-20 μm. When the total thickness of the coating is less than 0.1 μm, the effect of improving various properties such as wear resistance may not be sufficiently exhibited. When the total thickness of the coating exceeds 30 μm, the residual stress increases, Adhesion may be reduced, which is not preferable.

  In addition, as a measuring method of a film thickness, it can obtain | require by cut | disconnecting a cutting tool and observing the cross section using a scanning electron microscope (SEM: Scanning Electron Microscope). Below, each layer of the coating layer which comprises a film is demonstrated.

<Zr-containing coating layer>
The “Zr-containing coating layer”, which is at least one of the coating layers constituting the coating, is one of the coating layers included in the coating and is a layer containing Zr. By including this Zr-containing coating layer, both the toughness and the wear resistance of the surface-coated cutting tool can be achieved at a higher level than before.

  In the present invention, it may be expressed as “Zr contained in the film”, but it is not always necessary that the film contains Zr uniformly, and the Zr content is partially high or low. It may have a part.

  The relationship between the content of Zr contained in the coating and the wear resistance and toughness of the cutting edge portion tends to improve toughness as the content of Zr contained in the coating increases. As the content decreases, the wear resistance tends to improve.

  Here, in the present invention, “contains Zr” means that it is contained in an amount exceeding that contained as an unavoidable impurity, and it is difficult to show the amount contained in the film as this unavoidable impurity by a specific numerical value. However, if it dares to be specified, it means that Zr is contained in a ratio of 0.001% by mass or more with respect to the coating film.

  Further, Zr contained in the coating may be contained in the coating in a solid solution state, and it is contained in one or both of substitutional type and interstitial type in the matrix component crystal of the Zr-containing coating layer. It may be. The Zr-containing coating layer may also serve as one or both of an aluminum oxide layer and a titanium compound layer described later.

  Moreover, it is preferable that the thickness of such a Zr containing coating layer is 0.01-20 micrometers, More preferably, it is 0.1-15 micrometers, More preferably, it is 0.2-12 micrometers. When the thickness of the Zr-containing coating layer is less than 0.01 μm, the effect of improving various properties such as wear resistance may not be sufficiently exhibited. When the thickness of the Zr-containing coating layer exceeds 20 μm, the residual stress increases. There is a possibility that the adhesiveness with the substrate is lowered, which is not preferable.

  In the cutting edge part of the surface-coated cutting tool of the present invention, the Zr content of the coating in the first cutting edge part which is one cutting edge part among the cutting edge parts, and other cuttings excluding the first cutting edge part When the Zr content of the coating on at least one of the blades is different, the work material having a wide range of hardness and strength can be cut, and the number of replacement of the surface-coated cutting tool can be reduced. It is possible to provide a surface-coated cutting tool that can be used.

  Here, “the Zr content of the coating is“ different ”” clearly indicates that the Zr content of the coating at one cutting edge and the Zr content of the coating at the other cutting edge differ depending on any analysis method. Of course, it means that the difference may be a slight difference that can be regarded as substantially different.

  As described above, a surface-coated cutting tool capable of cutting a work material having a wide range of hardness and strength by adjusting the Zr content of the coating at the cutting edge portion to be different for each cutting edge portion is provided. can do. In order to enable the surface-coated cutting tool to cope with cutting of a work material having a wide range of hardness and strength, it is necessary to have different toughness and heat crack resistance for each cutting edge portion of the surface-coated cutting tool, For this purpose, it is ideal that the hardness and strength of every part of the surface-coated cutting tool are different.

  However, since it is expected that it is difficult to industrially produce a surface-coated cutting tool having different hardness and strength everywhere in the surface-coated cutting tool, the present inventor In particular, paying attention to the cutting edge part involved in cutting, and making the Zr content of the coating in each cutting edge part as non-uniform as possible, the toughness and heat resistance differing for each cutting edge part of the surface-coated cutting tool Thus, it is possible to provide a surface-coated cutting tool that can have cracking properties and can cope with a work material having a wide range of hardness and strength.

  According to the present invention, the Zr content of the coating film in each cutting edge portion of the surface-coated cutting tool is different for each cutting edge portion, and the Zr content of the coating film in each cutting blade portion is non-uniform, More specifically, it is preferable to satisfy the following conditions.

Zr content of the coating of the coated cutting tool of the present invention, among the Zr content of the coating in any one of the cutting edge portion, and the Zr content that Zr content is maximum and X _1, the Zr-containing When the Zr content that minimizes the amount is X ₂ and the average value of the Zr content of the coating in all the cutting edges is X _ave , X ₁ , X _2, and X _ave satisfy the following formula (I) Thus, a surface-coated cutting tool that can cut a wide range of work materials can be obtained. Moreover, since the difference of Zr content for every cutting edge part becomes large, so that the left side of Formula (I) shows a large value, the difference in the performance of hardness and strength for every cutting edge part becomes larger, and it is more wide range. It can be set as the surface covering cutting tool which can cut a work material. For this reason, the left side of the formula (I) is more preferably 0.08 or more, and further preferably 0.1 or more. The upper limit is preferably 0.5.

(X ₁ −X ₂ ) / X _ave ≧ 0.04 (I)
Further, the surface-coated cutting tool of the present invention has two rake faces, each of the rake faces has at least two diagonal lines, and both ends of the diagonal lines are included in the cutting edge portion. Of the rake faces, the rake face having the larger area is defined as the first rake face, the rake face having the smaller area as the second rake face, and any one of the diagonal lines of the first rake face. the average value of the Zr content of the film at the second cutting edge portion located in the first diagonal line across a diagonal line as Y _1, of the diagonal of the second rake face, is a diagonal parallel to the first diagonal first If the average value of the Zr content of the film at the second cutting edge portion located 2 opposite corners and Y _2, the average value of the Zr content of the film in all the cutting edge portion and the Y _ave, Y _1, by Y ₂ and Y _ave satisfy the following formula (II), a wide range of Work material it is possible to obtain a surface-coated cutting tool capable of cutting. Moreover, since the difference of Zr content for every cutting edge part becomes large, so that the left side of Formula (II) shows a large value, the difference in the performance of hardness and strength for every cutting edge part becomes larger, and it is more wide range. It can be set as the surface covering cutting tool which can cut a work material. For this reason, the left side of the formula (II) is more preferably 0.08 or more, and further preferably 0.1 or more. The upper limit is preferably 0.5.

(Y ₁ −Y ₂ ) / Y _ave ≧ 0.04 (II)
Here, in the surface-coated cutting tool 101 of the present invention, the upper surface in FIG. 1 is referred to as a first rake surface 102a, and the other rake surface is referred to as a second rake surface 102b. The rake face with the larger area of the two rake faces. When the areas of the two rake faces are equal, the first rake face 102a can be any face.

  Of the two diagonal lines included in the first rake face 102a, one diagonal line is referred to as a first diagonal line 105a, and one of the two diagonal lines included in the second rake face 102b is parallel to the first diagonal line 105a. Is called the second diagonal 105b.

  Here, the first diagonal line 105a and the second diagonal line 105b are "parallel" to the first diagonal line 105a of the first rake face 102a and the second rake face 102b in the three-dimensional structure of the surface-coated cutting tool 101. This means that the two diagonal lines 105b are not substantially in a twisted positional relationship.

In addition, the surface-coated cutting tool of the present invention has an average value Z of the Zr content of the coating at the two cutting edge portions located at both ends of the first shared ridge that is any one of the shared ridges. ₁ is the maximum among the average values of the Zr content of the coating at the two cutting edges located at both ends of the other shared ridge, and the second shared which is any one of the shared ridges The average value Z ₂ of the Zr content of the coating at the two cutting edges located at both ends of the ridge is the average value of the Zr content of the coating at the two cutting edges located at both ends of the other shared ridge. When the average value of the Zr content of the coating at all cutting edges is Z _ave , Z ₁ , Z ₂ and Z _ave satisfy the following formula (III) to cut a wide range of work materials A surface-coated cutting tool that can be obtained can be obtained. Moreover, since the difference of Zr content for every cutting edge part becomes large, so that the left side of Formula (III) shows a large value, the difference in the performance of the hardness and strength for every cutting edge part becomes larger, and a wider range. It can be set as the surface covering cutting tool which can cut a work material. For this reason, the left side of the formula (III) is more preferably 0.08 or more, and further preferably 0.1 or more. The upper limit is preferably 0.5.

(Z ₁ −Z ₂ ) / Z _ave ≧ 0.04 (III)
Moreover, it is preferable that a 1st shared edge crosses any one diagonal line among the diagonal lines in a said 1st rake face, and also this diagonal line also crosses the said 2nd shared edge. That is, in the case of the three-dimensional structure of the surface-coated cutting tool 101 as shown in FIG. 1, it is preferable that the first shared ridge and the second shared ridge are the shared ridges 104 at diagonal positions.

<Aluminum oxide layer>
The “aluminum oxide layer”, which is at least one of the coating layers constituting the coating, is a coating layer that is included in the coating at least one or more layers, and is a layer mainly containing aluminum oxide. This aluminum oxide layer mainly improves the welding resistance of the rake face and also improves the wear resistance during high-speed cutting. These effects are remarkable by using α-alumina for the aluminum contained in the aluminum oxide. In addition, when this aluminum oxide layer contains Zr, it becomes a Zr-containing coating layer.

  Moreover, the aluminum oxide layer may be exposed on the surface of the surface-coated cutting tool, or the aluminum oxide layer may be exposed only at the edge portion of the edge of the surface-coated cutting tool. Further, “including as a main component” means that the aluminum oxide layer contains at least 20% by mass of aluminum oxide and that the component other than aluminum oxide is a single component and does not contain an amount exceeding the content of aluminum oxide.

  Moreover, it is preferable that the thickness of such an aluminum oxide layer is 0.01-20 micrometers, More preferably, it is 0.1-15 micrometers, More preferably, it is 0.2-12 micrometers. When the thickness of the aluminum oxide layer is less than 0.01 μm, the effect of improving various properties such as wear resistance may not be sufficiently exhibited. When the thickness of the aluminum oxide layer exceeds 20 μm, the residual stress increases, There is a possibility that the adhesiveness with the lowering, which is not preferable.

<Titanium compound layer>
The “titanium compound layer”, which is at least one of the coating layers constituting the coating, is a coating layer contained in the coating at least one or more layers, and is a layer mainly containing a titanium compound. This titanium compound layer is a layer provided to improve wear resistance when used in general-purpose cutting, and is preferably formed by MT-CVD (Medium Temperature Chemical Vapor Deposition) method. It is preferable to use it. In addition, when this titanium compound layer contains Zr, it becomes a Zr-containing coating layer.

  Further, “including as a main component” means that the titanium compound layer contains at least 20% by mass of a titanium compound and a component other than the titanium compound is a single component and does not contain an amount exceeding the content of the titanium compound. Here, the content of the titanium compound contained in the titanium compound layer may include 20% by mass or more of a single type of titanium compound, or the content of a plurality of types of titanium compounds. A total of 20% by mass or more of a titanium compound may be included.

  Moreover, it is preferable that the thickness of such a titanium compound layer is 0.01-25 micrometers, More preferably, it is 0.1-18 micrometers, More preferably, it is 0.2-15 micrometers. When the thickness of the titanium compound layer is less than 0.01 μm, the effect of improving various properties such as wear resistance may not be sufficiently exhibited. When the thickness of the titanium compound layer exceeds 25 μm, the residual stress increases, There is a possibility that the adhesiveness with the lowering, which is not preferable.

<Hard compound layer>
The coating of the surface-coated cutting tool 101 of the present invention may contain at least one hard compound layer in addition to the Zr-containing coating layer. This hard compound layer is composed of IVa group elements (Ti, Zr, Hf, etc.), Va group elements (V, Nb, Ta, etc.), VIa group elements (Cr, Mo, W, etc.), Al, Si and A layer mainly comprising a compound consisting of at least one element selected from the group consisting of boron and at least one element selected from the group consisting of carbon, nitrogen, oxygen and boron is preferable. In addition, from the viewpoint of preventing deterioration in adhesion to the substrate while improving various properties such as wear resistance, at least one element selected from the group consisting of carbon, nitrogen, oxygen and boron, and titanium It is more preferable that the layer contains a compound as a main component.

  Further, when two or more hard compound layers are included, it is preferable that a compound constituting one hard compound layer is different from a compound constituting another hard compound layer. In addition, it is preferable that the thickness of one layer in the hard compound layer is 1-100 nm.

  In addition, “include as a main component” means that the hard compound layer includes a group IVa element (Ti, Zr, Hf, etc.), a group Va element (V, Nb, Ta, etc.), a group VIa element (Cr, Mo, etc.) in the periodic table. W, etc.), containing at least 20% by mass of a compound comprising at least one element selected from the group consisting of Al, Si and boron and at least one element selected from the group consisting of carbon, nitrogen, oxygen and boron In addition, the component other than this compound is a single component and does not contain an amount exceeding the content of this compound.

  In addition, as a compound which comprises such a hard compound layer, TiAl, TiSi, AlCr, TiN, TiON, TiCN, TiCNO, TiBN, TiCBN, TiAlCN, AlN, AlCN, AlCrCN, AlON, CrN, CrCN, TiSiN , TiSiCN, TiO, TiAlON, ZrN, ZrCN, AlZrN, TiAlN, TiAlSiN, TiAlCrSiN, AlCrN, AlCrSiN, TiZrN, TiAlMoN, TiAlNbN, TiSiN, TiSiCN, AlCrTaN, AlTiVN, TiB, TiCrHfN, TiB, TiCrHfN , AlHfN, CrSiBON, TiAlWN, AlCrMoCN, TiAlBN, TiAlCrS And the like can be given BCNO.

  In particular, examples of the compound composed of titanium and at least one element selected from the group consisting of carbon, nitrogen, oxygen and boron include TiN, TiBN, TiON, TiCN, TiCNO, and TiCBN.

  In the above chemical formula, those in which the atomic ratio of each element is not particularly described are not necessarily equivalent, and all conventionally known atomic ratios are included. For example, when simply describing TiN, the atomic ratio of Ti and N includes 1: 1, and includes 2: 1, 1: 0.95, 1: 0.9, etc. (unless otherwise noted, the following) The same).

  When two or more hard compound layers are included, a layer made of these compounds may be stacked with a thickness of 2 nm to 5 μm. In particular, at least one layer selected from the group consisting of at least one element selected from the group consisting of carbon, nitrogen, oxygen, and boron and a compound consisting of titanium has a thickness of 1 to 100 nm. It is preferable to include one or more super multilayers that are periodically stacked. Thus, by periodically laminating the above layers, the oxidation resistance and heat resistance are further improved, and extremely excellent wear resistance is exhibited.

  Here, periodically laminating means, for example, laminating with a certain periodicity such as alternately laminating two kinds of layers. In addition, when the thickness of each layer is less than 1 nm or exceeds 100 nm, the effect of improving the wear resistance by lamination may not be shown, but even in that case, the inherent wear resistance provided by these compounds The effect of improving sex is shown. The thickness of each layer is more preferably 4 to 60 nm.

  Moreover, it is preferable that such a hard compound layer has a thickness of 0.3 to 10 μm (when it is formed of a super multi-layer, its total thickness), more preferably 0.5 to 7 μm, still more preferably. Is 1-5 μm. If the thickness is less than 0.3 μm, sufficient wear resistance may not be exhibited and sufficient toughness may not be exhibited. If the thickness exceeds 10 μm, the fracture resistance may decrease, which is not preferable.

<Stress of coating>
At least one of the coating layers constituting the coating of the present invention may include either one or both of a layer having compressive residual stress and a layer having no stress. By including one or both of the layer with compressive residual stress and the layer without stress, it is possible to effectively prevent chipping of the cutting edge due to fatigue life when the surface-coated cutting tool is used for a long time. it can. The aluminum oxide layer described above may also serve as the layer having the compressive residual stress or the layer having no stress.

<Substrate composition>
As a composition used for the base material of the surface-coated cutting tool of the present invention, a conventionally known composition known as a base material for such a cutting tool can be used without any particular limitation. For example, cemented carbide (for example, WC-based cemented carbide, WC, including Co, or further including carbonitride such as Ti, Ta, Nb, etc.), cermet (TiC, TiN, TiCN) Etc.), high speed steel, ceramics (titanium carbide, silicon carbide, silicon nitride, aluminum nitride, aluminum oxide and mixtures thereof), cubic boron nitride sintered body, diamond sintered body It can be at least one selected from the group consisting of, etc.

  When a cemented carbide is used as such a base material, the effect of the present invention is exhibited even if such a cemented carbide contains an abnormal phase called free carbon or η phase in the structure. Moreover, the base material of the present invention may be further adjusted to a predetermined shape and dimensional accuracy by further processing with a grindstone, a brush or the like, if necessary, and a β-free layer is provided on the base material. Also good.

<Application>
The surface-coated cutting tool of the present invention can be used for all kinds of work materials that can be cut with this kind of tip, and its application is also drill, end mill, tip replacement type tip for drilling, end mill processing. For a wide range of applications such as cutting edge replacement inserts for milling, cutting edge replacement inserts for milling, cutting edge replacement inserts for turning, metal saws, gear cutting tools, reamers, tap or crankshaft pin milling inserts Can be used.

<Manufacturing method>
The surface-coated cutting tool of the present invention can form various coating layers on its substrate by chemical vapor deposition (CVD) or physical vapor deposition (PVD). Any method can be adopted as long as it is a method capable of forming such a coating layer, and the above-described effects of the present invention can be exhibited by any method.

  Here, when the various coating layers of the present invention are formed by the CVD method, the coating layers are formed by vapor-depositing a reaction gas on part or all of the surface of the substrate. The kind of gas used for the reaction gas may be a single component gas, but is preferably a mixed gas having two or more components.

As the reaction gas used in the present invention, a conventionally known reaction gas such as a halogenated mineral gas, a nonmetallic elemental gas, or the like can be used. For example, TiCl ₄ , ZrCl ₄ , BCl ₃ , HCl, At least one selected from the group consisting of AlCl ₃ , N ₂ , H ₂ , CH ₃ CN, CH ₄ , CO, CO ₂ , H ₂ S and the like is used, but is not limited to these reaction gases. Common reaction gases equivalent to these can be used. Moreover, as conditions required when this reactive gas is vapor-deposited on a base material, for example, temperature, pressure, and the like can be mentioned. In terms of temperature, it may be set in a range of 700 to 1300 ° C. It may be set in the range of 1 to 100 kPa.

  The coating layer contained in the coating of the surface-coated cutting tool of the present invention can also be formed by physical vapor deposition (PVD). Examples of such physical vapor deposition include balanced magnetron sputtering, unbalanced magnetron sputtering, arc ion plating, and combinations of these.

  The coating layer on the substrate of the surface-coated cutting tool of the present invention is produced, for example, by the following CVD method. That is, a base material setting jig 131 on which a base material 130 is set as shown in FIG. 2 is prepared, and the base material 130 and the base material setting jig 131 are connected to a reaction vessel 134 as shown in FIG. Then, the temperature in the reaction vessel is set in the range of 840 ° C. to 1020 ° C. by the high temperature heater 133, and the pressure in the reaction vessel is set in the range of 6 to 60 kPa. The raw material gas is put into the inside. The source gas introduced from the source gas inlet 136 passes through the reaction tube 138 and is released from the nozzle hole 135 of the reaction tube 138, and a part of the source gas adheres to the surface of the base material 130. A coating layer is formed on the substrate 130, and the remaining gas that has not adhered to the substrate 130 as a coating layer is discharged through the exhaust port 137.

  In forming the coating layer by this method, as shown in FIG. 4, the inter-nozzle distance 140, which is the distance between the substrate 130 and the center height 139 between the nozzles, is related to the distribution of the raw material of the coating layer. That is, the shorter the inter-nozzle distance 140 between the base material 130 and the center height 139 between nozzles, the easier the source gas is deposited on the base material 130, and the longer the distance between the base material 130 and the center height 139 between nozzles, the higher the source gas. Is difficult to deposit on the substrate 130. Therefore, when the source gas contains Zr, appropriately adjusting the inter-nozzle distance 140 is extremely important in determining the distribution of the Zr content of the coating film at the cutting edge.

In addition to the above-described method for adjusting the distance between nozzles, as a method for adjusting the distribution of the Zr content of the coating at the cutting edge, for example, the second rake face of the base material 130 and the base material setting jig 131 A method of adjusting the distance between the base material setting jig 131 and the center height 139 between the nozzles, a method of adjusting the way of introducing gas into the reaction vessel 134, and the amount of catalyst gas used And a method combining these methods. Here, for example, H ₂ S can be used as the “catalyst gas”.

  Examples Hereinafter, the present invention will be described in more detail with reference to Examples 1 to 4, but the present invention is not limited thereto.

<Example 1>
First, a mixed powder obtained by mixing TaC powder, NbC powder, TiC powder, Co powder and WC powder (mass of TaC powder: mass of NbC powder: mass of TiC powder: mass of Co powder: mass of WC powder = 1.0 : 1.2: 2.0: 8.0: 87.8) was sintered in a vacuum at a temperature of 1450 ° C. for 1 hour to prepare a sintered body.

  Next, each of the sintered bodies was processed so that a 23 μm thick de-β layer was formed, and then as a blade edge treatment, honing of 0.06 mm was performed as viewed from the scooping surface with a SiC brush. A base material made of a superalloy having the same shape as CNMG120408EMU manufactured by Hard Metal Co., Ltd. was produced. As shown in FIG. 2, the surface of the base material setting jig 131 and the second scooping surface of the base material 130 are in contact with the base material 130 thus obtained. It installed so that a surface might become an upper surface.

Next, as shown in FIG. 3, the conditions of the reaction vessel 134 of the CVD apparatus 132 are set to the temperature (° C.) and the pressure (kPa) shown in Table 1 below, and the raw material having the raw material gas composition shown in Table 1 By introducing the gas from the raw material gas inlet 136, the TiN layer (lower), the MT-TiCN layer (*), the α-Al ₂ O ₃ layer (*) and the TiN layer are formed on the surface of the base material 130 as shown in Table 2. A coating layer was formed by sequentially laminating according to the film thickness shown in FIG. 1 to produce the surface-coated cutting tool of Example 1. The unit of the thickness of each layer shown in Table 2 is μm.

In Table 1, the MT-TiCN layer is a TiCN layer formed by the MT-CVD method, and “MT-TiCN layer (*)” and “α-Al ₂ O ₃ layer (*)”. As described above, the coating layer indicated by (*) after the name of the coating layer indicates that Zr is contained in a part of the source gas, and is a Zr-containing coating layer. In addition, the coating layer represented as “TiN layer (lower)” is a TiN layer in which a part or all of the base material 130 is in contact among the plurality of TiN layers included in the coating.

  Here, the inter-nozzle distance (mm) shown in Table 2 refers to the inter-nozzle center height 139 of the reaction tube 138 and the first rake face (upper surface of the base material) of the base material 130, as shown in FIG. Is the distance. The inter-nozzle distance 140 when the height of the center height 139 between the nozzles is higher than the height of the first rake face of the base material 130 is expressed as a positive number, and the height of the center height 139 between the nozzles is the base material 130. The inter-nozzle distance 140 when the height of the first rake face is lower than the first rake face is represented by a negative number.

  The Zr content increases as the cutting edge portion has a shorter distance from the straight line indicating the center height 139 between the nozzles. That is, for example, the Zr content of the cutting edge part on the upper surface (first rake face) side of the surface-coated cutting tool 130 in FIG. 4 is the Zr content of the cutting edge part on the lower surface (second rake face) side of the surface-coated cutting tool 130. More than the content. And the cutting edge part by the side of the 1st rake face with much Zr content will be excellent in toughness, and the cutting edge part by the side of the 2nd rake face with low Zr content will be excellent in abrasion resistance.

  In Example 1, as shown in Table 2, the surface-coated cutting tool No. 1 obtained by sintering the nozzle-to-nozzle distance 140 at 6 mm was obtained. 101, the surface-coated cutting tool obtained by sintering with a nozzle distance 140 of 4 mm is the surface-coated cutting tool No. No. 102, and the surface-coated cutting tool obtained by sintering with a nozzle distance 140 of 2 mm is the surface-coated cutting tool No. No. 103, and the surface-coated cutting tool obtained by sintering at a nozzle distance 140 of −2 mm is the surface-coated cutting tool No. 104.

  The surface-coated cutting tool No. obtained in this way. 101 to 104, as shown in FIG. 5, the rake face on the upper surface is the first rake face 202, the first rake face different from the first rake face 202 is the second rake face, and the other side faces are the other faces. It was a negative tip for the flank 203. This surface-coated cutting tool 201 includes a cutting edge portion 207a having a sandwiching angle (an angle formed by two adjacent cutting edge ridge lines 206a and 206b) at both ends of the first diagonal line 205a of the first rake face 202; And a cutting edge portion 207c and a cutting edge portion 207d having an included angle of 80 ° at both ends of the second diagonal line of the second rake face.

<Intermittent cutting test>
Surface coated cutting tool No. manufactured as described above. 10 to 101 are prepared for each tool, and each tool has a cutting edge portion on the first rake face side that is short from the straight line indicating the center height 139 between nozzles at the time of manufacture, that is, at both ends of the first diagonal line 205a. The intermittent cutting test shown below was performed on the cutting edge portions 207a and 207b, and the defect rate of these cutting edge portions was determined and shown in Table 3. Here, the defect rate is a value representing the ratio of the number of missing cutting edge parts to the cutting edge parts (total 20 cutting edge parts per each tool) subjected to the intermittent cutting test, and the numerical value is small. It shows that it is excellent in fracture resistance.

(Intermittent cutting test conditions)
Work material: SCM435, round bar with 4 grooves of diameter 250mm Use holder: PCLNR2525-43 (Sumitomo Electric Hardmetal Co., Ltd.)
Cutting speed: 100 m / min
Feed: 0.40 mm / rev.
Cutting depth: 2.5mm
Cutting time: 30 seconds Cutting oil: None <Continuous cutting test>
Further, the surface-coated cutting tool No. Ten pieces of 101 to 104 are prepared, and the cutting edge part on the second rake face side, which is a long distance from the straight line indicating the center height 139 between nozzles at the time of manufacture for each tool, that is, a second diagonal line (not shown). The cutting edge 207c and the cutting edge 207d at both ends are subjected to a continuous cutting test under the conditions shown below, and the average value of the flank wear (V _B ) of these cutting edges is obtained and shown in Table 3. It was. The smaller the numerical value of the flank wear amount (V _B ), the better the wear resistance.

(Conditions for continuous cutting test)
Work material: SCM415, round bar with a diameter of 250 mm Use holder: PCLNR2525-43 (manufactured by Sumitomo Electric Hardmetal Co., Ltd.)
Cutting speed: 320 m / min
Feed: 0.32 mm / rev.
Cutting depth: 1.5mm
Cutting time: 5 minutes Cutting oil: Water-soluble oil <Measurement of Zr content>
Surface coated cutting tool No. For each of 101 to 104, each cutting edge portion is cut by a plane including a bisector of the included angle formed by the adjacent cutting edge ridge line 206a and cutting edge ridge line 206b, and the coating film portion of the cutting surface is cut into an electron beam microanalyzer. (EPMA: Electron Probe MicroAnalyser) measured 10 times in a spot size range of 2 μm, and the average of the 10 measurements was taken as the Zr content of the coating at the cutting edge.

Using the Zr content of the coating at the cutting edge thus obtained, the average value Y _ave (mass%) of the Zr content of the coating at all cutting edges, the cutting edge 207a and the cutting edge 207b. The average value Y ₁ (mass%) of the Zr content of the coating film and the average value Y ₂ (mass%) of the Zr content of the coating film at the cutting edge portion 207c and the cutting edge portion 207d were obtained. Y _ave , Y ₁ and Y ₂ are shown in Table 3.

As is apparent from Table 3, the surface-coated cutting tool No. 1 of Example 1 of the present invention was used. The average value Y _ave of the Zr content of the coating in all the cutting edges 101 is 1.218% by mass, and the Zr of the coating in the cutting edges 207a and 207b at both ends of the first diagonal line 205a. The average value Y ₁ of the content is 1.422% by mass, and the average value Y ₂ of the Zr content of the coating at the cutting edge 207c and the cutting edge 207d at both ends of the second diagonal (not shown). Is 1.013% by mass, the value of (Y ₁ −Y ₂ ) / Y _ave shown on the left side of the formula (II) is 0.336, which is on the right side of the formula (II). It was 0.04 or more shown, and the condition of the formula (II) was satisfied.

Further, the surface-coated cutting tool No. 1 of Example 1 of the present invention was used. Average value Y _ave of Zr content of the film in all of the cutting edge portion 102 is 1.352 mass%, Zr of the coating in the cutting edge portion 207a and the cutting edge portion 207b at both ends of the first diagonal line 205a The average value Y ₁ of the content is 1.437% by mass, and the average value Y ₂ of the Zr content of the coating film at the cutting edge 207c and the cutting edge 207d at both ends of the second diagonal (not shown). Is 1.266 mass%, the value of (Y ₁ −Y ₂ ) / Y _ave shown on the left side of the formula (II) is 0.127, which is on the right side of the formula (II). It was 0.04 or more shown, and the condition of the formula (II) was satisfied.

Further, the surface-coated cutting tool No. 1 of Example 1 of the present invention was used. The average value Y _ave of the Zr content of the coating in all the cutting edges 103 is 1.418% by mass, and the Zr of the coating in the cutting edges 207a and 207b at both ends of the first diagonal line 205a. The average value Y ₁ of the content is 1.449% by mass, and the average value Y ₂ of the Zr content of the coating at the cutting edge 207c and the cutting edge 207d at both ends of the second diagonal (not shown). Is 1.386% by mass, the value of (Y ₁ −Y ₂ ) / Y _ave shown on the left side of the formula (II) is 0.044, which is on the right side of the formula (II). It was 0.04 or more shown, and the condition of the formula (II) was satisfied.

In contrast, the surface-coated cutting tool No. 1 of Comparative Example 1 was used. The average value Y _ave of the Zr content of the coating in all the cutting edges 104 is 1.899 mass%, and the Zr of the coating in the cutting edges 207a and 207b at both ends of the first diagonal line 205a. The average value Y ₁ of the content is 1.912% by mass, and the average value Y ₂ of the Zr content of the coating at the cutting edge 207c and the cutting edge 207d at both ends of the second diagonal (not shown). Is 1.85% by mass, the value of (Y ₁ −Y ₂ ) / Y _ave shown on the left side of the formula (II) is 0.014, which is on the right side of the formula (II). It was less than 0.04 shown and did not satisfy the conditions of the formula (II).

Further, as apparent from the flank wear amount V _B (mm) in Table 3 by the continuous cutting test, the surface-coated cutting tool No. 1 of Example 1 was used. 101, no. 102 and no. 103 is a surface-coated cutting tool No. 1 of Comparative Example 1. It was found that the flank wear amount V _B was superior to 104.

  On the other hand, as is apparent from the defect rate in Table 3 according to the intermittent cutting test, the surface-coated cutting tool No. 1 of Example 1 was used. 101, no. 102 and no. 103 is a surface-coated cutting tool No. 1 of Comparative Example 1. Compared to 104, it was found that the fracture resistance was also excellent.

  From the above, the surface-coated cutting tool in which the Zr content of the coating at the cutting edge satisfies the condition of the formula (II) is different from the surface-coated cutting tool not satisfying the condition of the formula (II). Because of their different hardness and strength, they can handle a wider range of work materials. In addition, since the wear resistance and fracture resistance are improved, the surface-coated cutting tool can reduce the number of replacements of the surface-coated cutting tool.

<Example 2>
Using the base material 130 manufactured in Example 1, a coating layer was formed on the surface of the base material 130 in the same manner as in Example 1. In Example 2, the TiN layer (lower), MT-TiCN layer (*), MT-TiCN layer, TiBN layer, α-Al ₂ O ₃ layer, κ-Al ₂ O ₃ layer, TiCN layer and TiN layer At least four coating layers selected from the group were sequentially laminated according to the film thicknesses shown in Table 4 to form a coating layer. In addition, the unit of the layer thickness of each layer shown in Table 4 is μm, and the symbol “−” means that the layer in the corresponding column is not formed in the coating layer.

  Here, the inter-nozzle distance shown in Table 4 is determined by the same method as in Example 1. The surface-coated cutting tool obtained by sintering with the inter-nozzle distance 140 of 5 mm is the surface-coated cutting tool no. 201, no. 202 and No. 203, a surface-coated cutting tool obtained by sintering at a nozzle distance 140 of -1 mm is a surface-coated cutting tool No. 204, no. 205 and No. 206.

<Intermittent cutting test>
Surface coated cutting tool No. manufactured as described above. Each of the tools 201 to 206 is prepared, and at each end of the first rake face 205a on the first rake face side where the distance from the straight line indicating the center height 139 between the nozzles is short for each tool during manufacture. The intermittent cutting test shown below was performed for a certain cutting edge part 207a and the cutting edge part 207b, the defect rate of these cutting edge parts was determined, and each defect rate is shown in Table 5.

(Intermittent cutting test conditions)
Work material: SCM435, round bar with 4 grooves of diameter 250mm Use holder: PCLNR2525-43 (Sumitomo Electric Hardmetal Co., Ltd.)
Cutting speed: 105 m / min
Feed: 0.40 mm / rev.
Cutting depth: 2.2mm
Cutting time: 30 seconds Cutting oil: None <Continuous cutting test>
No. 10 pieces of 201 to 206 are prepared, and the cutting edge portion on the second rake face side having a long distance from the straight line indicating the center height 139 between nozzles at the time of manufacture for each tool, that is, a second diagonal line (not shown) The cutting edge 207c and the cutting edge 207d at both ends are subjected to a continuous cutting test under the conditions shown below, and the average value of the flank wear amount (V _B ) of these cutting edges is obtained. The flank wear amount (V _B ) is shown in Table 5 below.

(Conditions for continuous cutting test)
Work material: SCM415, round bar with a diameter of 250 mm Use holder: PCLNR2525-43 (manufactured by Sumitomo Electric Hardmetal Co., Ltd.)
Cutting speed: 260 m / min
Feed: 0.30 mm / rev.
Cutting depth: 1.5mm
Cutting time: 5 minutes Cutting oil: Water-soluble oil <Measurement of Zr content>
Surface coated cutting tool No. 201 and no. For 204, each cutting edge portion is cut by a surface including a bisector of the included angle formed by the adjacent edge ridgeline 206a and edge ridgeline 206b, and the coating portion of the cutting surface is subjected to an electron microanalyzer (EPMA: Electron). Probe MicroAnalyser) was measured 10 times in a spot size range of 1 μm, and the average of the 10 measurements was taken as the Zr content of the coating at the cutting edge.

Using the Zr content of the coating at the cutting edge thus obtained, the average value Y _ave (mass%) of the Zr content of the coating at all cutting edges, the cutting edge 207a and the cutting edge 207b. The average value Y ₁ (mass%) of the Zr content of the coating film and the average value Y ₂ (mass%) of the Zr content of the coating film at the cutting edge portion 207c and the cutting edge portion 207d were obtained. Y _ave , Y ₁ and Y ₂ are shown in Table 5.

  Further, the surface-coated cutting tool No. 202 and No. For 205, the measurement object is limited to the MT-TiCN layer of the coating on the cut surface in the same manner as described above, and measured 10 times with an electron probe microanalyzer (EPMA) at a spot size of 1 μm. The average of the 10 measurements was taken as the Zr content of the MT-TiCN layer at the cutting edge.

Using the Zr content of the MT-TiCN layer in the cutting edge portion thus determined, the average value Y _ave (mass%) of the Zr content of the coating in all the cutting edge portions, particularly the MT-TiCN layer, The average value Y ₁ (mass%) of the Zr content of the coating at the blade portion 207a and the cutting blade portion 207b, particularly the MT-TiCN layer, and the coating at the cutting blade portion 207c and the cutting blade portion 207d, particularly the MT-TiCN layer. The average value Y ₂ (mass%) of the Zr content was obtained, and these values Y _ave , Y ₁ and Y ₂ are shown in Table 5.

  Further, the surface-coated cutting tool No. 203 and no. For 206, the measurement target is limited to the α-alumina layer of the coating on the cut surface in the same manner as described above, and measured 10 times with an electron probe microanalyzer (EPMA) at a spot size of 1 μm. The average of the ten measurements was taken as the Zr content of the coating at the cutting edge, particularly the α-alumina layer.

Using the Zr content of the α-alumina layer in the cutting edge portion thus obtained, the average value Y _ave (mass%) of the Zr content of the coating in all the cutting edge portions, particularly the α-alumina layer, the cutting edge The average value Y ₁ (mass%) of the Zr content of the coating, particularly the α-alumina layer, of the coating at the blade portion 207a and the cutting blade portion 207b, and particularly the coating of the α-alumina layer, at the cutting blade portion 207c and the cutting blade portion 207d. The average value Y ₂ (mass%) of the Zr content was obtained, and these values Y _ave , Y ₁ and Y ₂ are shown in Table 5.

As is apparent from Table 5, the surface-coated cutting tool No. The average value Y _ave of the Zr content of the coating in all the cutting edges 201 is 1.272% by mass, and the Zr of the coating in the cutting edges 207a and 207b at both ends of the first diagonal line 205a. The average value Y ₁ of the content is 1.432% by mass, and the average value Y ₂ of the Zr content of the coating at the cutting edge 207c and the cutting edge 207d at both ends of the second diagonal (not shown). Is 1.112% by mass, the value of (Y ₁ −Y ₂ ) / Y _ave shown on the left side of the formula (II) is 0.252, which is on the right side of the formula (II). It was 0.04 or more shown, and the condition of the formula (II) was satisfied.

Further, the surface-coated cutting tool No. 2 of Example 2 of the present invention was used. The average value Y _ave of the Zr content of the MT-TiCN layer in all the cutting edge parts 202 is 1.228% by mass, and the cutting edge part 207a and the cutting edge part 207b at both ends of the first diagonal line 205a. The average value Y ₁ of the Zr content of the MT-TiCN layer is 1.385% by mass, and the MT-TiCN layer at the cutting edge 207c and the cutting edge 207d at both ends of the second diagonal (not shown) mean value Y ₂ of Zr content, since it is 1.071 mass%, the value of the _{(Y 1 -Y 2) / Y} ave that shown in the left side of the formula (II) is 0.256, This was 0.04 or more shown on the right side of the formula (II), which satisfied the condition of the formula (II).

Further, the surface-coated cutting tool No. 2 of Example 2 of the present invention was used. The average value Y _ave of the Zr content of the α-alumina layer in all the cutting edge parts 203 is 0.352 mass%, and the cutting edge part 207a and the cutting edge part 207b at both ends of the first diagonal line 205a. mean value Y ₁ of the Zr content of the alpha-alumina layer is 0.396 wt%, alpha-alumina layer in a cutting edge portion 207c and the cutting edge portion 207d at both ends of the second diagonal line (not shown) Since the average value Y ₂ of the Zr content is 0.307% by mass, the value of (Y ₁ −Y ₂ ) / Y _ave shown on the left side of the formula (II) is 0.253, This was 0.04 or more shown on the right side of the formula (II), which satisfied the condition of the formula (II).

In contrast, the surface-coated cutting tool No. The average value Y _ave of the Zr content of the coating in all the cutting edge parts 204 is 1.835% by mass, and the cutting edge part 207a, the cutting edge part 207b, and the cutting edge part at both ends of the first diagonal 205a. The average value Y ₁ of the Zr content of the coating is 1.852% by mass, and the average of the Zr content of the coating at the cutting edge 207c and the cutting edge 207d at both ends of the second diagonal (not shown). Since the value Y ₂ is 1.818 mass%, the value of (Y ₁ −Y ₂ ) / Y _ave shown on the left side of the formula (II) is 0.019, which is expressed by the formula (II) It was less than 0.04 shown on the right side of and did not satisfy the condition of formula (II).

Further, the surface-coated cutting tool No. 1 of Comparative Example 2 was used. The average value Y _ave of the Zr content of the MT-TiCN layer in all the cutting edges 205 is 1.760% by mass, and the cutting edge 207a and the cutting edge 207b at both ends of the first diagonal 205a The average value Y ₁ of the Zr content of the MT-TiCN layer is 1.775% by mass, and the MT-TiCN layer at the cutting edge 207c and the cutting edge 207d at both ends of the second diagonal (not shown) mean value Y ₂ of Zr content, since it is 1.745 mass%, the value of the _{(Y 1 -Y 2) / Y} ave that shown in the left side of the formula (II) is 0.017, This was less than 0.04 shown on the right side of the formula (II), and the condition of the formula (II) was not satisfied.

Further, the surface-coated cutting tool No. 1 of Comparative Example 2 was used. The average value Y _ave of the Zr content of the α-alumina layer in all the cutting edge portions 206 is 0.505% by mass, and the cutting edge portions 207a and 207b at both ends of the first diagonal line 205a The average value Y ₁ of the Zr content of the α-alumina layer is 0.513% by mass, and the α-alumina layer at the cutting edge 207c and the cutting edge 207d at both ends of the second diagonal (not shown). Since the average value Y ₂ of the Zr content of is 0.496 mass%, the value of (Y ₁ −Y ₂ ) / Y _ave shown on the left side of the formula (II) is 0.034, This was less than 0.04 shown on the right side of the formula (II), and the condition of the formula (II) was not satisfied.

Further, as apparent from the flank wear amount V _B (mm) in Table 5 by the continuous cutting test, the surface-coated cutting tool No. 2 of Example 2 was used. 201, no. 202 and No. No. 203 is a surface-coated cutting tool No. 204, no. 205 and No. It was found that the flank wear amount V _B was superior to 206. On the other hand, as apparent from the defect rate in Table 5 by the intermittent cutting test, the surface-coated cutting tool No. 2 of Example 2 was used. 201, no. 202 and No. No. 203 is a surface-coated cutting tool No. 204, no. 205 and No. Compared to 206, it was found that the fracture resistance was also excellent.

  From the above, the surface-coated cutting tool in which the Zr content of the coating at the cutting edge satisfies the condition of the formula (II) is different from the surface-coated cutting tool not satisfying the condition of the formula (II). Because of different hardness and strength, it can handle a wider range of work materials. In addition, since the wear resistance and fracture resistance are improved, the surface-coated cutting tool can reduce the number of replacements of the surface-coated cutting tool. Thereby, even if the Zr content of the coating, particularly the MT-TiCN layer, satisfies the condition of the formula (II), the same effect is obtained, and the Zr content of the coating, particularly the α-alumina layer, is the condition of the formula (II). It was found that the same effect can be obtained even if the above is satisfied.

<Example 3>
First, TaC powder, NbC powder, ZrCN powder, Co powder and WC powder mixed powder (mass of TaC powder: mass of NbC powder: mass of ZrCN powder: mass of Co powder: mass of WC powder = 0.5 : 1.5: 0.5: 10.0: 87.5) was sintered in a vacuum at a temperature of 1450 ° C. for 1 hour to prepare a sintered body.

  Next, each of the sintered bodies was processed so that a 15 μm-thick de-β layer was formed, followed by 0.06 mm honing as seen from the rake face with a SiC brush as the blade edge treatment. A base material made of a superalloy having the same shape as CNMG120408EUX manufactured by Hard Metal Co., Ltd. was produced. As shown in FIG. 6, the base material 130 thus obtained is fitted into the hole in the setting jig 131 so that the second common ridge 204 b of the base material 130 faces, and the first shared ridge 204 a of the base material 130 faces upward. Installed.

Next, as shown in FIG. 7, the conditions of the reaction vessel 134 of the CVD apparatus 132 are set to the temperature (° C.) and the pressure (kPa) shown in Table 1, and the source gas having the source gas composition shown in Table 1 is set. By introducing from the source gas inlet 136, a TiN layer (lower), MT-TiCN layer (*), MT-TiCN layer, TiBN layer, TiBNO layer, α-Al ₂ O ₃ layer on the surface of the base material 130 , Κ-Al ₂ O ₃ layer, TiCN layer, and TiN layer, at least four coating layers were sequentially laminated according to the film thicknesses shown in Table 6 to form a coating layer. In addition, the unit of the layer thickness of each layer shown in Table 6 is μm, and the symbol “−” means that the layer in the corresponding column is not formed on the coating layer.

  The inter-nozzle distance (mm) shown in Table 6 is the distance between the straight line indicating the inter-nozzle center height 139 of the reaction tube 138 and the first shared ridge of the substrate 130 as shown in FIG. is there. The inter-nozzle distance 141 when the height of the center height 139 between the nozzles is higher than the first shared ridge of the substrate 130 is a positive number, and the height of the center height 139 between the nozzles is the first height of the substrate 130. The inter-nozzle distance 141 when the height of the shared ridge is lower than the common ridge is a negative number.

  In Example 3, as shown in Table 6, the surface-coated cutting tool No. 1 obtained by sintering the nozzle-to-nozzle distance 141 at 3 mm was sintered. 301, no. 302 and no. 303, and the surface-coated cutting tool obtained by sintering at a nozzle-to-nozzle distance 141 of −4 mm is the surface-coated cutting tool No. 304, no. 305 and No. 306.

<Intermittent cutting test>
Surface coated cutting tool No. 10 pieces each of 301 to 306 are prepared, and for each tool, a ridge line positioned on the upper side of the surface-coated cutting tool at the time of manufacture, that is, the cutting edge portion 207a and the cutting edge portion 207c at both ends of the first shared ridge 204a The intermittent cutting test shown below was performed, the defect rates of these cutting edges were determined, and the respective defect rates are shown in Table 7.

(Intermittent cutting test conditions)
Work Material: S50C, Round Bar with 4 Grooves 250mm in Diameter Use Holder: PCLNR2525-43 (Sumitomo Electric Hard Metal Co., Ltd.)
Cutting speed: 80 m / min
Feed: 0.38 mm / rev.
Cutting depth: 2.0mm
Cutting time: 30 seconds Cutting oil: None <Continuous cutting test>
Surface coated cutting tool No. 10 pieces each of 301 to 306 are prepared, and the cutting edge portion 207b and the cutting edge portion 207d on the side located in the hole of the base material setting jig at the time of manufacture for each tool, that is, both ends of the second shared ridge 204b. A continuous cutting test was conducted under the conditions shown below, and the average value of the flank wear amount (V _B ) of these cutting edges was determined. The respective flank wear amounts (V _B ) are shown in Table 7 below. Indicated.

(Conditions for continuous cutting test)
Work material: S50C, round bar with a diameter of 250 mm Holder: PCLNR2525-43 (manufactured by Sumitomo Electric Hardmetal Co., Ltd.)
Cutting speed: 270 m / min
Feed: 0.32 mm / rev.
Cutting depth: 2.0mm
Cutting time: 5 minutes Cutting oil: Water-soluble oil <Measurement of Zr content>
Surface coated cutting tool No. 301 and no. 304, each cutting edge part is cut | disconnected by the surface containing the bisector of the narrow angle which the adjacent blade edge ridgeline 206a and the blade edge ridgeline 206b make, and the part of the film of the cut surface is an electron beam microanalyzer (EPMA: Electron). Probe MicroAnalyser) was measured 10 times in a spot size range of 1 μm, and the average of the 10 measurements was taken as the Zr content of the coating at the cutting edge.

Using the Zr content of the coating film in the cutting edge portion thus obtained, the average value Z _ave (mass%) of the Zr content of the coating film in all the cutting edge portions and the both ends of the first shared ridge 204a The average value Z ₁ (mass%) of the Zr content of the coating at the cutting edge 207a and the cutting edge 207c, and the Zr of the coating at the cutting edge 207b and the cutting edge 207d at both ends of the second shared ridge 204b The average value Z ₂ (mass%) of the content was obtained, and these values Z _ave , Z ₁ and Z ₂ are shown in Table 7.

  Further, the surface-coated cutting tool No. 302 and no. For 305, in the same manner as described above, the measurement object is limited to the MT-TiCN layer of the coating on the cut surface, and 10 times with an electron beam microanalyzer (EPMA: Electron Probe MicroAnalyser) is measured 10 times. The average of the 10 measurements was taken as the Zr content of the coating at the cutting edge, particularly the MT-TiCN layer.

Using the Zr content of the MT-TiCN layer in the cutting edge portion thus determined, the average value Z _ave (% by mass) of the Zr content of the coating in all the cutting edge portions, particularly the MT-TiCN layer, The average value Z ₁ (mass%) of the Zr content of the MT-TiCN layer in the cutting edge 207a and the cutting edge 207c at both ends of the first shared ridge 204a, and the cutting edges at both ends of the second shared ridge 204b The average value Z ₂ (mass%) of the Zr content of the MT-TiCN layer in the part 207b and the cutting edge part 207d was obtained, and these values Z _ave , Z ₁ and Z ₂ are shown in Table 7.

  Further, the surface-coated cutting tool No. 303 and no. For 306, in the same manner as described above, the measurement object is limited to the α-alumina layer of the coating on the cut surface, and measured 10 times with an electron probe microanalyzer (EPMA: Electron Probe MicroAnalyser) at a spot size of 1 μm. The average of the ten measurements was taken as the Zr content of the coating at the cutting edge, particularly the α-alumina layer.

Using the Zr content of the α-alumina layer in the cutting edge portion thus determined, the average value Z _ave (mass%) of the Zr content of the coating in all the cutting edge portions, particularly the α-alumina layer, and The average value Z ₁ (mass%) of the Zr content of the α-alumina layer in the cutting edge 207a and the cutting edge 207c at both ends of the first shared ridge 204a, and the cutting edges at both ends of the second shared ridge 204b The average value Z ₂ (mass%) of the Zr content of the α-alumina layer in the part 207b and the cutting edge part 207d was obtained, and these values Z _ave , Z ₁ and Z ₂ are shown in Table 7.

As is apparent from Table 7, the surface-coated cutting tool No. 3 of Example 3 of the present invention was used. The average value Z _ave of the Zr content of the coating in all the cutting edges 301 is 0.803 mass%, and the coating of the coating in the cutting edges 207a and the cutting edges 207c at both ends of the first shared ridge 204a. The average value Z ₁ of the Zr content is 0.854% by mass, and the average value Z ₂ of the Zr content of the coating at the cutting edge 207b and the cutting edge 207d at both ends of the second shared ridge 204b is 0 since it is 0.751 mass%, the value of is shown in formula _{(III) (Z 1 -Z 2} ) / Z ave is 0.128, which is shown on the right-hand side of formula (III). It was 04 or more, and the condition of the formula (III) was satisfied.

Further, the surface-coated cutting tool No. 3 of Example 3 of the present invention was used. The average value Y _ave of the Zr content of the MT-TiCN layer in all the cutting edge portions 302 is 0.842% by mass, and the cutting edge portions 207a and 207c at both ends of the first shared edge 204a The average value Z ₁ of the Zr content of the MT-TiCN layer at 0.887% by mass is Zr of the MT-TiCN layer at the cutting edge 207b and the cutting edge 207d at both ends of the second shared ridge 204b. Since the average value Z ₂ of the content is 0.796% by mass, the value of (Z ₁ −Z ₂ ) / Z _ave shown on the left side of the formula (III) is 0.108. It was 0.04 or more shown by the right side of Formula (III), and satisfy | filled the conditions of Formula (III).

Further, the surface-coated cutting tool No. 3 of Example 3 of the present invention was used. The average value Y _ave of the Zr content of the α-alumina layer in all the cutting edge portions 303 is 0.323 mass%, and the cutting edge portions 207a and 207c at both ends of the first shared edge 204a The average value Z ₁ of the Zr content of the α-alumina layer at 0.32 is 0.342% by mass, and the Zr of the α-alumina layer at the cutting edge 207b and the cutting edge 207d at both ends of the second shared ridge 204b. Since the average value Z ₂ of the content is 0.304 mass%, the value of (Z ₁ −Z ₂ ) / Z _ave shown on the left side of the formula (III) is 0.118, It was 0.04 or more shown by the right side of Formula (III), and satisfy | filled the conditions of Formula (III).

In contrast, the surface-coated cutting tool No. The average value Y _ave of the Zr content of the film in all the cutting edge parts 304 is 0.906 mass%, and the coating film in the cutting edge part 207a and the cutting edge part 207c at both ends of the first shared edge 204a. The average value Z ₁ of the Zr content is 0.922% by mass, and the average value Z ₂ of the Zr content of the coating at the cutting edge 207b and the cutting edge 207d at both ends of the second shared ridge 204b is Since it is 0.889 mass%, the value of (Z ₁ −Z ₂ ) / Z _ave shown on the left side of the formula (III) is 0.036, which is shown on the right side of the formula (III). It was less than 0.04, and the condition of formula (III) was not satisfied.

Further, the surface-coated cutting tool No. 1 of Comparative Example 3 was used. The average value Y _ave of the Zr content of the MT-TiCN layer in all the cutting edge parts 305 is 0.905 mass%, and the cutting edge part 207a and the cutting edge part 207c at both ends of the first shared edge 204a mean value Z ₁ of the Zr content of the MT-TiCN layer in is 0.918 mass%, Zr in the second shared edge 204b MT-TiCN layer in the cutting edge portion 207b and the cutting edge portion 207d at both ends of the Since the average value Z ₂ of the content is 0.892% by mass, the value of (Z ₁ −Z ₂ ) / Z _ave shown on the left side of the formula (III) is 0.029. It was less than 0.04 shown on the right side of the formula (III), and the condition of the formula (III) was not satisfied.

Further, the surface-coated cutting tool No. 1 of Comparative Example 3 was used. The average value Y _ave of the Zr content of the α-alumina layer in all the cutting edges of 306 is 0.417% by mass, and the cutting edges 207a and 207c at both ends of the first shared edge 204a mean value Z ₁ of the Zr content of α- alumina layer in is 0.424 mass%, Zr of α- alumina layer in a cutting edge portion 207b and the cutting edge portion 207d at both ends of the second shared edges 204b mean value Z ₂ of content, since it is 0.410 mass%, the value of the _{(Z 1 -Z 2) / Z} ave of shown in the left side of the formula (III) is 0.034, which is It was less than 0.04 shown on the right side of the formula (III), and the condition of the formula (III) was not satisfied.

Further, as is clear from the flank wear amount V _B (mm) in Table 7 by the continuous cutting test, the surface-coated cutting tool No. 3 of Example 3 was used. 301, no. 302 and no. 303 is a surface-coated cutting tool No. 3 of Comparative Example 3. 304, no. 305 and No. It was found that the flank wear amount V _B was superior to 306. On the other hand, as is clear from the defect rate in Table 7 by the intermittent cutting test, the surface-coated cutting tool No. 1 of Example 3 was used. 301, no. 302 and no. 303 is a surface-coated cutting tool No. 3 of Comparative Example 3. 304, no. 305 and No. Compared to 306, it was found that the fracture resistance was also excellent.

  From the above, the surface-coated cutting tool in which the Zr content of the coating film at the cutting edge satisfies the condition of the formula (III) is different from the surface-coated cutting tool that does not satisfy the condition of the formula (III). Because of different hardness and strength, it can handle a wider range of work materials. In addition, since the wear resistance and fracture resistance are improved, the surface-coated cutting tool can reduce the number of replacements of the surface-coated cutting tool. Thereby, even if the Zr content of the coating, particularly the MT-TiCN layer, satisfies the condition of the formula (III), the same effect is obtained, and the Zr content of the coating, particularly the α-alumina layer, is the condition of the formula (III). It was found that the same effect can be obtained even if the above is satisfied.

<Example 4>
First, a mixed powder obtained by mixing TaC powder, NbC powder, TiC powder, Co powder and WC powder (mass of TaC powder: mass of NbC powder: mass of TiC powder: mass of Co powder: mass of WC powder = 2.0 : 2.0: 1.5: 5.5: 89.0) was sintered in a vacuum at a temperature of 1460 ° C. for 1 hour to prepare a sintered body.

  Next, each of the sintered bodies was processed so as to form a de-β layer having a thickness of 22 μm, followed by cutting edge treatment, and finally 0.06 mm as viewed from the rake face with a SiC brush. Honing was performed, and a superalloy base material having the same shape as CNMG120408ESU manufactured by Sumitomo Electric Hardmetal Co., Ltd. was produced. As shown in FIG. 2, the surface of the base material setting jig 131 and the second scooping surface of the base material 130 are in contact with the base material 130 thus obtained. It installed so that a surface might become an upper surface.

Next, as shown in FIG. 3, the base material setting jig 131 is installed in the CVD apparatus 132, and the conditions of the reaction vessel 134 of the CVD apparatus 132 are set to the temperature (° C.) and the pressure (kPa) shown in Table 1. Then, by introducing the raw material gas having the raw material composition shown in Table 1 from the raw material gas inlet 136, the TiN layer (lower), MT-TiCN layer (*), α-Al on the surface of the base material 130. _{The 2} O ₃ layer (*) and the TiN layer were sequentially laminated according to the film thicknesses shown in Table 8 to form a coating layer, and a surface-coated cutting tool of Example 4 was produced.

  Here, as shown in Table 8, the inter-nozzle distance 140 was changed for each composition of the raw material gas of the coating layer shown in Table 1. Specifically, the surface-coated cutting tool No. 401 sinters the coating layer of the TiN layer (lower) at the inter-nozzle distance of −1 mm, sinters the coating layer of the MT-TiCN layer (*) at the inter-nozzle distance of −1 mm, and then α at the inter-nozzle distance of 4 mm. -The alumina coating layer was sintered, and the TiN coating layer was further sintered at a nozzle-to-nozzle distance of -1 mm.

  Further, the surface-coated cutting tool No. 402 sinters the coating layer of the TiN layer (lower) at a distance between nozzles of −1 mm, sinters the coating layer of the MT-TiCN layer (*) at a distance of 4 mm between nozzles, and then α at a distance between nozzles of −1 mm. -The alumina coating layer was sintered, and the TiN coating layer was further sintered at a nozzle-to-nozzle distance of -1 mm.

  Further, the surface-coated cutting tool No. 403 sinters the coating layer of the TiN layer (lower) at a distance between nozzles of −1 mm, sinters the coating layer of the MT-TiCN layer (*) at a distance of 4 mm between nozzles, and then α− at a distance of 4 mm between the nozzles. The alumina layer coating layer was sintered, and further the TiN layer coating layer was sintered at a distance between nozzles of −1 mm.

  Further, the surface-coated cutting tool No. 404 sinters the coating layer of the TiN layer (lower) at the inter-nozzle distance of −1 mm, sinters the coating layer of the MT-TiCN layer (*) at the inter-nozzle distance of −1 mm, and then the inter-nozzle distance of −1 mm. The coating layer of the α-alumina layer was sintered, and the coating layer of the TiN layer was further sintered at a distance between nozzles of −1 mm.

<Intermittent cutting test>
Surface coated cutting tool No. manufactured as described above. Ten pieces each of 401 to 404 are prepared, and at each end of the first rake face 205a on the first rake face side where the distance from the straight line indicating the center height 139 between the nozzles is short for each tool during manufacture. The intermittent cutting test shown below was performed for a certain cutting edge portion 207a and cutting edge portion 207b, the defect rates of these cutting edge portions were determined, and the respective defect rates are shown in Table 9.

(Intermittent cutting test conditions)
Work material: SCr420H, round bar with 4 grooves of diameter 250mm Used holder: PCLNR2525-43 (Sumitomo Electric Hardmetal Co., Ltd.)
Cutting speed: 100 m / min
Feed: 0.35 mm / rev.
Cutting depth: 2.0mm
Cutting time: 30 seconds Cutting oil: None <Continuous cutting test>
Further, the surface-coated cutting tool No. 10 each of 401 to 404 is prepared, and the cutting edge part on the second rake face side having a long distance from the straight line indicating the center height 139 between the nozzles at the time of manufacture, that is, the cutting edge part 207c of the second rake face 202; off subjected to continuous cutting test under the following conditions for the blade section d, the average value of flank wear of cutting edge portions (V _B), each of the flank wear amount (V _B) of the following It is shown in Table 9.

(Conditions for continuous cutting test)
Work material: S35C, round bar with a diameter of 250 mm Holder used: PCLNR2525-43 (manufactured by Sumitomo Electric Hard Metal Co., Ltd.)
Cutting speed: 300 m / min
Feed: 0.28 mm / rev.
Cutting depth: 1.5mm
Cutting time: 20 minutes Cutting oil: Water-soluble oil <Measurement of Zr content>
Surface coated cutting tool No. About 401-404, each cutting edge part is cut | disconnected by the surface containing the bisector of the included angle which the cutting edge ridgeline 206a and the cutting edge ridgeline 206b adjoin, and especially the part of the MT-TiCN layer part of the film of the cut surface An electron beam microanalyzer (EPMA: Electron Probe MicroAnalyser) measured 10 times in a spot size range of 0.5 μm, and the average of the 10 measurements was taken as the Zr content of the MT-TiCN layer at the cutting edge.

The average value Y _ave (% by mass) of the Zr content of the MT-TiCN layer in all the cutting edges, using the Zr content of the coating in the cutting edge part thus obtained, in particular the MT-TiCN layer, the average of Zr content of MT-TiCN layer in a blade portion 207a and the cutting edge portion 207b off value Y ₁ (wt%), the Zr content of the MT-TiCN layer in the cutting edge portion 207c and the cutting edge portion 207d The average value Y ₂ (mass%) was obtained, and these values Y _ave , Y ₁ and Y ₂ are shown in Table 9.

  Further, in the same manner as described above, the surface-coated cutting tool No. For 401 to 404, the object to be measured is limited to the α-alumina layer of the coating on the cut surface, and the spot size is measured 10 times with an electron probe microanalyzer (EPMA: Electron Probe MicroAnalyser). The average of the measured values was taken as the Zr content of the α-alumina layer at the cutting edge.

Using the Zr content of the α-alumina layer in the cutting edge portion thus obtained, the average value Y _ave (mass%) of the Zr content of the coating in all the cutting edge portions, particularly the α-alumina layer, the cutting edge the average value of the Zr content of α- alumina layer at a blade portion 207a and the cutting edge portion 207b Y ₁ (wt%) and the cutting edge portion 207c and the cutting edge portion average value of the Zr content of α- alumina layer in a 207d Y ₂ (mass%) values were obtained and these values Y _ave , Y ₁ and Y ₂ are shown in Table 9.

As is clear from Table 9, the surface-coated cutting tool No. The average value Y _ave of the Zr content of the MT-TiCN layer in all the cutting edge parts 401 is 2.117% by mass, and the cutting edge part 207a and the cutting edge part 207b at both ends of the first diagonal line 205a. mean value Y ₁ of the Zr content of the MT-TiCN layer is 2.117 wt%, MT-TiCN layer in the cutting edge portion 207c and the cutting edge portion 207d at both ends of the second diagonal line (not shown) Since the average value Y ₂ of the Zr content of 2.117% by mass, the value of (Y ₁ −Y ₂ ) / Y _ave shown on the left side of the formula (II) is 0.000, This was less than 0.04 shown on the right side of the formula (II), and the condition of the formula (II) was not satisfied.

Further, the surface-coated cutting tool No. The average value Y _ave of the Zr content of the α-alumina layer in all the cutting edge parts 401 is 0.748% by mass, and the cutting edge part 207a and the cutting edge part 207b at both ends of the first diagonal line 205a. The average value Y ₁ of the Zr content of the α-alumina layer is 0.893% by mass, and the α-alumina layer at the cutting edge 207c and the cutting edge 207d at both ends of the second diagonal (not shown). Since the average value Y ₂ of the Zr content is 0.684% by mass, the value of (Y ₁ −Y ₂ ) / Y _ave shown on the left side of the formula (II) is 0.279, This was 0.04 or more shown on the right side of the formula (II), which satisfied the condition of the formula (II).

Further, the surface coated cutting tool No. The average value Y _ave of the Zr content of the MT-TiCN layer in all the cutting edge parts 402 is 1.948% by mass, and the cutting edge part 207a and the cutting edge part 207b at both ends of the first diagonal line 205a. mean value Y ₁ of the Zr content of the MT-TiCN layer is 2.073 wt%, MT-TiCN layer in the cutting edge portion 207c and the cutting edge portion 207d at both ends of the second diagonal line (not shown) Since the average value Y ₂ of the Zr content is 1.823 mass%, the value of (Y ₁ -Y ₂ ) / Y _ave shown on the left side of the formula (II) is 0.128, This was 0.04 or more shown on the right side of the formula (II), which satisfied the condition of the formula (II).

Further, the surface-coated cutting tool No. The average value Y _ave of the Zr content of the α-alumina layer in all the cutting edges 402 is 0.913% by mass, and the cutting edge 207a and the cutting edge 207b at both ends of the first diagonal line 205a. The average value Y ₁ of the Zr content of the α-alumina layer is 0.913% by mass, and the α-alumina layer at the cutting edge 207c and the cutting edge 207d at both ends of the second diagonal (not shown). Since the average value Y ₂ of the Zr content is 0.912% by mass, the value of (Y ₁ −Y ₂ ) / Y _ave shown on the left side of the formula (II) is 0.001. This was less than 0.04 shown on the right side of the formula (II), and the condition of the formula (II) was not satisfied.

Further, the surface-coated cutting tool No. 4 of Example 4 of the present invention was used. The average value Y _ave of the Zr content of the MT-TiCN layer in all of the cutting edges 403 is 1.948% by mass, and the cutting edge 207a and the cutting edge 207b at both ends of the first diagonal line 205a. The average value Y ₁ of the Zr content of the MT-TiCN layer is 2.073% by mass, and the MT-TiCN layer at the cutting edge 207c and the cutting edge 207d at both ends of the second diagonal (not shown) Since the average value Y ₂ of the Zr content is 1.823 mass%, the value of (Y ₁ -Y ₂ ) / Y _ave shown on the left side of the formula (II) is 0.128, This was 0.04 or more shown on the right side of the formula (II), which satisfied the condition of the formula (II).

Further, the surface-coated cutting tool No. The average value Y _ave of the Zr content of the α-alumina layer in all the cutting edges of 403 is 0.748% by mass, and the cutting edge 207a and the cutting edge 207b at both ends of the first diagonal line 205a. The average value Y ₁ of the Zr content of the α-alumina layer is 0.893% by mass, and the α-alumina layer at the cutting edge 207c and the cutting edge 207d at both ends of the second diagonal (not shown). Since the average value Y ₂ of the Zr content is 0.684% by mass, the value of (Y ₁ −Y ₂ ) / Y _ave shown on the left side of the formula (II) is 0.279, This was 0.04 or more shown on the right side of the formula (II), which satisfied the condition of the formula (II).

In contrast, the surface-coated cutting tool No. The average value Y _ave of the Zr content of the coating in all the cutting edge portions 404 is 2.117% by mass, and the cutting edge portions 207a, the cutting edge portions 207b, and the cutting edge portions at both ends of the first diagonal line 205a. The average value Y ₁ of the Zr content of the coating is 2.117% by mass, and the average of the Zr content of the coating at the cutting edge 207c and the cutting edge 207d at both ends of the second diagonal (not shown). Since the value Y ₂ is 2.118% by mass, the value of (Y ₁ −Y ₂ ) / Y _ave shown on the left side of the formula (II) is 0.000, which is expressed by the formula (II) It was less than 0.04 shown on the right side of and did not satisfy the condition of formula (II).

Further, the surface-coated cutting tool No. The average value Y _ave of the Zr content of the MT-TiCN layer in all the cutting edge portions 404 is 0.913% by mass, and the cutting edge portions 207a and 207b at both ends of the first diagonal line 205a The average value Y ₁ of the Zr content of the MT-TiCN layer is 0.913% by mass, and the MT-TiCN layer at the cutting edge 207c and the cutting edge 207d at both ends of the second diagonal (not shown). Since the average value Y ₂ of the Zr content is 0.912% by mass, the value of (Y ₁ −Y ₂ ) / Y _ave shown on the left side of the formula (II) is 0.001. This was less than 0.04 shown on the right side of the formula (II), and the condition of the formula (II) was not satisfied.

Further, as apparent from the flank wear amount V _B (mm) in Table 9 by the continuous cutting test, the surface-coated cutting tool No. 4 of Example 4 was used. 401 to 403 are surface-coated cutting tool Nos. It was found that the flank wear amount V _B was superior to 404. Further, as apparent from the defect rate in Table 9 by the intermittent cutting test, the surface-coated cutting tool No. 4 in Example 4 was used. 401 to 403 are surface-coated cutting tool Nos. As compared with 404, it was found that the fracture resistance was also excellent.

  From the above, the surface-coated cutting tool in which the Zr content of one or both of the MT-TiCN layer and the α-alumina layer of the coating at the cutting edge satisfies the formula (II) is represented by the formula (II). Compared with a surface-coated cutting tool that does not satisfy the above conditions, the hardness and strength of each cutting edge portion are different, so that a wider range of work materials can be handled. In addition, since the wear resistance and fracture resistance are improved, the surface-coated cutting tool can reduce the number of replacements of the surface-coated cutting tool.

  As described above, the embodiments of the present invention have been described, but it is also planned from the beginning to appropriately combine the configurations of the above-described embodiments.

  It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  According to the present invention, it is possible to provide a surface-coated cutting tool that can cut a work material having a wide range of hardness and strength and can reduce the number of replacements of the surface-coated cutting tool.

It is a typical perspective view of a preferable example of the surface covering cutting tool of the present invention. It is the schematic diagram which looked at the jig | tool for base-material setting after installing so that the surface of the jig | tool for base-material setting and the 2nd rake face of a base material may be contact | connected. It is typical sectional drawing of a CVD apparatus after installing the jig | tool for base material setting. It is an expanded sectional view of the CVD apparatus which shows the positional relationship of the center height between nozzles, and a base material at the time of installing so that the jig | tool for base material setting and the 2nd rake face of a base material may contact | connect. It is a typical perspective view which shows the surface coating cutting tool of the Example of this invention. It is the schematic diagram which looked at the base material setting jig | tool which fitted the shared ridge of the base material in the hole of the base material setting jig from right above. It is typical sectional drawing which shows the CVD apparatus after installing the base material setting jig | tool which fitted the shared ridge of the base material in the hole of the base material setting jig. It is an expanded sectional view of a CVD device showing the positional relationship between the center height between nozzles and the base material when the common ridge of the base material is installed so as to fit into the hole of the base material setting jig.

Explanation of symbols

  101, 201 Surface coated cutting tool, 102a, 202 first rake face, 102b second rake face, 103, 203 flank face, 104 common ridge, 105a, 205a first diagonal line, 105b second diagonal line, 106, 106a, 106b, 206, 206a, 206b Edge edge line, 107, 207a, 207b, 207c, 207d Cutting edge part, 130 base material, 131 base material setting jig, 132 CVD apparatus, 133 high temperature heater, 134 reaction vessel, 135 nozzle hole, 136 Source gas input port, 137 exhaust port, 138 reaction tube, 139 center height between nozzles, 140, 141 distance between nozzles, 204a first shared ridge, 204b second shared ridge.

Claims (10)

A surface-coated cutting tool comprising a substrate and a coating formed on the substrate,
The coating includes at least one coating layer,
At least one of the coating layers is a Zr-containing coating layer containing Zr,
The surface-coated cutting tool has two or more cutting edge portions,
The Zr content of the coating in the first cutting edge which is one of the cutting edges is the coating in at least one of the other cutting edges excluding the first cutting edge. A surface-coated cutting tool that is different from the Zr content. The Zr content of the coating is
Of Zr content of the coating in any one of the cutting edge portion, and the Zr content that Zr content is maximum and X _1, and the Zr content that Zr content is minimized and X _2,
When the average value of the Zr content of the coating at all the cutting edges is X _ave ,
The surface-coated cutting tool according to claim ₁ , wherein X ₁ , X ₂ and X _ave satisfy the following formula (I).
(X ₁ −X ₂ ) / X _ave ≧ 0.04 (I) The surface-coated cutting tool has two rake faces,
Each of the rake faces has at least two diagonal lines,
The diagonal line includes both ends of the diagonal line in the cutting edge part,
Of the rake faces, the rake face with the larger area is the first rake face, the rake face with the smaller area is the second rake face,
Of the diagonal lines of the first rake face, the average value of the Zr content of the coating in the two cutting edge portions located at both ends of the first diagonal line that is any one of the diagonal lines is Y ₁ ,
Of the diagonal lines of the second rake face, the average value of the Zr content of the coating at the two cutting edges located at both ends of the second diagonal line that is a diagonal line parallel to the first diagonal line is Y ₂ ,
When the average value of the Zr content of the coating in all the cutting edges is Y _ave ,
The surface-coated cutting tool according to claim ₁ , wherein Y ₁ , Y ₂ and Y _ave satisfy the following formula (II).
(Y ₁ −Y ₂ ) / Y _ave ≧ 0.04 (II) The surface-coated cutting tool has at least two flank surfaces;
One flank of the flank has one ridge that intersects at least one flank of the other flank as a shared ridge,
There are a plurality of the shared ridges in the surface-coated cutting tool, and both ends of the shared ridge are included in the cutting edge part,
Among the shared edges, any one mean value Z ₁ of the Zr content of the film at the second cutting edge portions located at both ends of the first shared edge which is shared crest is located at both ends of the other shared edges It becomes the maximum among the average values of the Zr content of the coating at the cutting edge part of 2,
Among the shared ridges, the average value Z ₂ of the Zr content of the coating at the two cutting edges located at both ends of the second shared ridge which is any one of the shared ridges is positioned at both ends of the other shared ridge. It becomes the smallest among the average values of the Zr content of the coating at the cutting edge part of 2,
All the average value of the Zr content of the coating on the cutting edge if the Z _ave,
The surface-coated cutting tool according to claim ₁ , wherein Z ₁ , Z _2, and Z _ave satisfy the following formula (III).
(Z ₁ −Z ₂ ) / Z _ave ≧ 0.04 (III)   5. The surface-coated cutting tool according to claim 4, wherein the first shared edge intersects any one of the diagonal lines on the first rake face, and the diagonal line also intersects the second shared edge.   The surface-coated cutting tool according to claim 1, wherein the surface-coated cutting tool is a negative tip.   The surface-coated cutting tool according to any one of claims 1 to 6, wherein the coating includes one or both of an aluminum oxide layer mainly containing aluminum oxide and a titanium compound layer mainly containing a titanium compound.   The surface-coated cutting tool according to any one of claims 1 to 7, wherein the Zr-containing coating layer is one or both of the aluminum oxide layer and the titanium compound layer. The coating includes at least one hard compound layer in addition to the Zr-containing coating layer,
The hard compound layer includes at least one element selected from the group consisting of group IVa elements, group Va elements, group VIa elements, Al, Si and boron in the periodic table, and a group consisting of carbon, nitrogen, oxygen and boron. The surface-coated cutting tool according to any one of claims 1 to 8, wherein the surface-coated cutting tool is a layer mainly comprising a compound composed of at least one element selected from the above.   The surface-coated cutting tool according to claim 9, wherein the hard compound layer is a layer mainly including a compound composed of titanium and at least one element selected from the group consisting of carbon, nitrogen, oxygen, and boron.

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