JP2012228751A - Cutting insert made of surface-coated titanium carbonitride based cermet, and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting insert made of a surface-coated TiCN based cermet which exhibits excellent resistance to breakage and excellent accuracy of machined surface under a high-load cutting condition, and a method of manufacturing the cutting insert.SOLUTION: This cutting insert made of a surface-coated TiCN based cermet is formed by coating an insert base body, which includes a through hole for fitting to a tool body, a flank, a honing part, a face and a chip breaker provided in the face, with a hard coating layer by a PVD method. The surface of a support tool contact face of the through hole is not coated with the hard coating layer and has a surface roughness which exceeds 0.2 μm (Ra) at 0.08 mm of cut-off value, the flank and the chip breaker of the insert base body has a surface roughness of 0.2 μm or below (Ra), and the residual stress of a hard phase of the surface part of the flank is 450 MPa or more in compression. Therefore, the cutting insert made of a surface-coated TiCN based cermet has excellent resistance to breakage and excellent finished surface accuracy.

Description

  The present invention is a titanium carbonitride-based (TiCN-based) cermet cutting insert that is attached to various types of insert detachable tools and used for cutting, and in particular, an insert substrate made of TiCN-based cermet is hardened by physical vapor deposition (PVD method). The present invention relates to a surface-coated TiCN-based cermet cutting insert having a coating layer formed thereon and a method for manufacturing the same, and has a through-hole for mounting to a tool body in particular, and is excellent in that there is little abnormal damage even in high-load cutting TECHNICAL FIELD The present invention relates to a surface-coated TiCN-based cermet cutting insert capable of obtaining a finished surface accuracy and a method for producing the same.

  Conventionally, Ti carbide or nitride or carbonitride is the main component, and one or more of carbides or nitrides or carbonitrides of group IVa elements, group Va elements, group VIa elements in the periodic table of elements A TiCN-based cermet cutting insert made of a hard phase contained and a metal bonded phase mainly composed of one or two of Ni and Co is widely known (Patent Documents 1 and 2). Such a TiCN-based cermet cutting insert is usually formed with a cutting edge portion at the intersecting ridge line portion between the rake face and the flank face of a polygonal flat plate-like insert body, and chips generated during the cutting process are formed. For control purposes, a chip breaker is generally formed on the rake face. In addition, such a cutting insert is usually provided with a mounting through-hole penetrating the board surface, and as shown in FIG. 4 (a) or FIG. A tool body attachment means (support), for example, an L-shaped lever, a screw, an eccentric pin, or the like is inserted into the through hole for use, and is attached to the tool body.

Furthermore, in order to improve the heat resistance, wear resistance, and toughness of conventional TiCN-based cermet cutting inserts, it is also known to reduce the maximum surface roughness of the burned surface of the insert surface to 3.5 μm or less. (Patent Document 3).

  On the other hand, the surface of the cutting insert base made of TiCN-based cermet as described above is selected from IVa group element, Va group element, VIa group element, Al, Si, Y, Mn, Ni, and S in the periodic table. A hard coating layer composed of one or more compounds composed of at least one element and at least one element selected from carbon, nitrogen, oxygen, and boron is coated by a physical vapor deposition method (PVD method). Surface-coated TiCN-based cermet cutting inserts formed are also known. For example, this type of surface-coated TiCN-based cermet cutting inserts are not limited to TiCN-based cermets but include tungsten carbide-based (WC-based) cemented carbides. There is something.

  The surface-coated TiCN-based cermet cutting insert as described above has a case where a hard coating layer does not exist by coating a hard coating layer made of a suitable hard material on the surface of a cutting insert base made of TiCN-based cermet. It is known that the wear resistance is improved in comparison. Further, for the purpose of improving the wear resistance of the surface-coated TiCN-based cermet cutting insert, for example, in the proposal of Patent Document 4, for example, the surface of the TiCN-based cermet cutting insert has substantially spherical steel, cast particles, heavy metal. Residue generated in hard coating layer formed by PVD method on cutting insert by projecting powder, glass, corundum, hard metal particles, fracture resistant ceramic, etc. with compressed air and applying so-called dry blast treatment It has been proposed to apply a residual stress similar to the stress in the vicinity of the surface of the cutting insert. In such a surface-coated TiCN-based cermet cutting insert of Patent Document 4, there is a gap between the cutting insert and the hard coating layer. By reducing the residual stress difference, the wear resistance is further improved compared to conventional coated inserts. It has been to the top.

JP-A-9-108908 JP-A-9-207005 Japanese Patent Laid-Open No. 2-15139 Special table 2009-523618

TiCN-based cermet cutting inserts are considered to be tool materials with low fracture resistance compared to tungsten carbide-based (WC-based) cemented carbide cutting inserts. Therefore, it was often used under light load cutting conditions.
Here, as a TiCN-based cermet insert used for cutting under normal conditions of light load, by reducing the surface roughness and making it a smooth surface, the fracture resistance is improved and the finished surface accuracy is also improved. For example, when wet blasting is performed as a means for smoothing the insert surface, the surface roughness of the insert is a smooth surface with an arithmetic average roughness Ra of 0.2 μm or less at a cutoff value of 0.08 mm. Has improved fracture resistance, improved the finished surface accuracy of the work material, and is able to form a glossy cutting surface.In addition, when performing wet blasting, the insert surface is The present inventors have found that the chipping resistance is further improved by applying a predetermined compressive residual stress to the insert surface simultaneously with smoothing. Such a tendency has been confirmed to be the same when TiCN-based cermet is used as an insert base and the surface thereof is covered with a hard coating layer by the PVD method.

  However, in recent years, high-efficiency machining has been demanded in the field of cutting, and the load on the cutting edge during cutting tends to be higher. For example, a TiCN-based cermet cutting insert attached to the tool body with a support such as an L-shaped lever as shown in FIG. 4A or a screw as shown in FIG. When used under cutting conditions where a high load is applied to the cutting edge such as the above, in addition to generation of defects from the cutting edge, cracks and breakage from the surface of the inner surface of the insert through hole that contacts the support At present, the service life is reached in a relatively short time. And when damage from the inner surface of the through hole occurs, it becomes impossible to replace the same insert with another cutting edge, which is a fatal problem as a detachable insert. Such a problem is unavoidable even with a TiCN-based cermet cutting insert as shown in Patent Document 3, for example, and is a TiCN insert with a reduced surface roughness by applying wet blasting as described above. However, it could not be resolved reliably and sufficiently. Further, such a problem also occurs in a conventional surface-coated TiCN-based cermet cutting insert in which a TiCN-based cermet is used as an insert substrate and a hard coating layer is formed on the surface thereof by the PVD method, such as the insert of Patent Document 4 described above. Was occurring as well.

As described above, conventionally, no particular consideration has been given to the occurrence of cracks or breakage from the inner surface of the insert through hole that comes into contact with the support tool under high-load cutting conditions. It is the actual situation that could not be avoided.
Therefore, the present invention suppresses the occurrence and development of cracks and breakage from the inner surface of the through hole even when the surface-coated TiCN-based cermet cutting insert is used under cutting conditions in which a high load acts on the cutting edge. It is an object of the present invention to provide a surface-coated TiCN-based cermet cutting insert that can reliably and sufficiently improve fracture resistance, and thereby exhibit excellent cutting performance over a long period of use, and a method for manufacturing the same. .

  The inventors have made a hard coating layer on the surface of an insert substrate made of TiCN-based cermet having a chip breaker on a through hole for mounting to a tool body, a flank surface, a honing part, a rake face, and a rake face by a PVD method. In a surface-coated TiCN-based cermet cutting insert (hereinafter referred to as a surface-coated TiCN insert) formed by forming an inner surface of a mounting through-hole (support tool contact surface) that comes into contact with a support tool such as a screw, L-shaped lever, or eccentric pin As a result of studying the relation between the state of the surface and the force for holding the surface-coated TiCN insert to the tool body, the support contact surface in the mounting through-hole is not covered with the hard coating layer by the PVD method, and an appropriate surface roughness is obtained. By using a rough surface, cracks and damage from the support contact surface of the through hole even under cutting conditions with high loads Generating progress can suppress, therefore exhibits excellent cutting performance over a long period of use, it was found that attained the life extension of the tool life.

  In other words, under cutting conditions in which an extremely high load is applied to the insert, such as intermittent cutting or milling, an unusually small load is applied to the insert held by the tool body due to the continuous variable load acting on the cutting edge. When vibration occurs, it has an adverse effect on the fracture resistance and the finished surface accuracy of the work material, and if the vibration is larger, cracks and breakage may occur from the support contact surface of the through hole for mounting the insert. The inventors have confirmed. Such abnormal micro vibrations of the insert have a low frictional force between the attachment means with the tool body such as an L-shaped lever or a screw, that is, the support and the inner surface of the insert through hole with which the support is in contact. As a result of studying the solution based on this, it is considered that there is a possibility that the insert slips due to the slippage of the insert. The surface (support device contact surface) in contact with the attachment means (support device) is not covered with the hard coating layer, and the surface roughness of the support device contact surface is a rough surface (specifically, a predetermined value or more). Is a rough surface exceeding 0.2 μm in arithmetic mean roughness Ra at a cut-off value of 0.08 mm), between the surface of the support and the support contact surface of the through hole that contacts the support surface. Even under cutting conditions where the frictional force increases and a high load acts, the surface-coated TiCN insert is firmly and securely held on the tool body, and abnormal micro-vibration is prevented from being generated in the surface-coated TiCN insert. As a result, it has been found that cracks, breakage, and progress from the support contact surface of the mounting through-hole can be suppressed, and the occurrence of defects can be suppressed, and a machined surface with high finished surface accuracy can be formed. Invented the invention.

Accordingly, the surface-coated titanium carbonitride-based cermet cutting insert according to the basic form (first form) of the present invention includes a through hole for attachment to a tool body, a flank, a honing portion, and a rake face, and the rake. Hardly coated with a physical vapor deposition method (PVD method) on the surface of an insert substrate made of a titanium carbonitride-based cermet having a chip breaker formed by transferring the mold shape during press molding In a surface-coated titanium carbonitride based cermet cutting insert coated with a layer;
Of the inner surface of the mounting through-hole, at least a support tool contact surface that comes into contact with a support tool as means for attaching to the tool body is configured by a surface that is not covered by the hard coating layer, and the support tool contact surface is The surface roughness of the surface of the insert base is more than 0.2 μm as the arithmetic average roughness Ra at a cutoff value of 0.08 mm. The arithmetic average roughness Ra at 0.08 mm is 0.2 μm or less, and the residual stress of the hard phase at least on the surface portion of the rake face in the insert substrate is 450 MPa or more in compression.

  The surface-coated titanium carbonitride-based cermet cutting insert according to the second aspect of the present invention is the surface-coated titanium carbonitride-based cermet cutting insert according to the first aspect, wherein at least the support contact surface of the through hole is baked. The surface roughness of the contact surface of the support member is set to 0.3 μm or more in terms of arithmetic average roughness Ra at a cutoff value of 0.08 mm.

  Furthermore, the surface-coated titanium carbonitride-based cermet cutting insert according to the third aspect of the present invention is the surface-coated titanium carbonitride-based cermet cutting insert according to the first or second mode, wherein at least the rake in the insert substrate is used. The residual stress of the hard phase in the surface portion of the surface is 600 MPa or more in compression.

  And the surface-coated titanium carbonitride-based cermet cutting insert according to the fourth embodiment of the present invention is the surface-coated titanium carbonitride-based cermet cutting insert according to any one of the first to third embodiments, The surface roughness of the honing part at the tip of the cutting edge in the insert base is formed smaller than the flank of the insert base and the surface roughness of the chip breaker.

  The surface-coated titanium carbonitride-based cermet cutting insert according to the fifth aspect of the present invention is the surface-coated titanium carbonitride-based cermet cutting insert according to any one of the first to fourth embodiments, The surface roughness of the honing part in the insert substrate is characterized by an arithmetic average roughness Ra of 0.1 μm or less at a cutoff value of 0.08 mm.

  Furthermore, the surface-coated titanium carbonitride-based cermet cutting insert according to the sixth embodiment of the present invention is the surface-coated titanium carbonitride-based cermet cutting insert according to any one of the first to fifth embodiments, The hard coating layer is composed of at least one element selected from the group IVa element, group Va element, group VIa element, Al, Si, Y, Mn, Ni, and S in the periodic table, and carbon, nitrogen, oxygen, It is characterized by comprising one layer or two or more layers of a compound comprising at least one element selected from boron.

  The surface-coated titanium carbonitride-based cermet cutting insert according to the seventh aspect of the present invention is the surface-coated titanium carbonitride-based cermet cutting insert according to the sixth aspect, wherein at least one of the hard coating layers is , TiAlN layer is used.

  The surface-coated titanium carbonitride-based cermet cutting insert according to the eighth aspect of the present invention is the surface-coated titanium carbonitride-based cermet cutting insert according to the sixth aspect, wherein the hard coating layer is Ti carbide, nitrided It consists of one layer or two or more layers selected from the above-mentioned materials and carbonitrides, and the total film thickness of the hard coating layer is 0.5 to 15 μm.

  Further, the surface-coated titanium carbonitride-based cermet cutting insert according to the ninth aspect of the present invention is the surface-coated titanium carbonitride-based cermet cutting insert according to the eighth embodiment as the hard coating layer from the insert base side. A TiN layer having a thickness of 0.1 to 1.0 μm, a TiCN layer having a thickness of 0.5 to 5.0 μm, and a TiN layer having a thickness of 0.1 to 1.0 μm are sequentially coated. It is a feature.

Furthermore, the tenth to nineteenth aspects of the present invention relate to a method for producing a surface-coated titanium carbonitride-based cermet cutting insert.
That is, first, the manufacturing method of the surface-coated titanium carbonitride-based cermet cutting insert according to the tenth embodiment of the present invention,
Titanium carbonitride-based cermet having a through-hole for attachment to a tool body, a flank, a honing portion, and a rake face, and having a chip breaker formed by transferring the mold shape to the rake face during press molding In a method for producing a surface-coated titanium carbonitride-based cermet cutting insert formed by coating an insert base composed of a sintered body with a hard coating layer by physical vapor deposition;
By the sintering method, the surface roughness of the support contact surface contacting at least the support as the means for attaching to the tool body in the mounting through hole is 0.2 μm in terms of arithmetic average roughness Ra at a cutoff value of 0.08 mm. An insert substrate manufacturing process for manufacturing an insert substrate having a roughness exceeding
By performing wet blasting in at least the region of the surface of the insert base body excluding the contact surface of the support, the surface roughness of the flank and the chip breaker is set to an arithmetic average roughness Ra at a cutoff value of 0.08 mm. And a wet blasting process in which the residual stress of the hard phase of the surface portion of the rake face is at least 450 MPa by compression,
After the wet blasting step, a coating step of forming a hard coating layer by a physical vapor deposition method in a region excluding at least the support contact surface of the surface of the insert substrate,
It is characterized by having.

  The method for producing a surface-coated titanium carbonitride-based cermet cutting insert according to the eleventh aspect of the present invention is the method for producing a surface-coated titanium carbonitride-based cermet cutting insert according to the tenth aspect, wherein the wet blasting step is performed. Then, while holding the insert substrate sandwiched between a pair of rotating shafts rotatable around an axis, and rotating around the axis, the polishing liquid is sprayed from at least one blast gun, and at least the support is supported. The insert base surface excluding the tool contact surface is subjected to wet blasting.

  The method for producing a surface-coated titanium carbonitride-based cermet cutting insert according to the twelfth aspect of the present invention is the method for producing a surface-coated titanium carbonitride-based cermet cutting insert according to the eleventh aspect. Then, a wet blasting process is performed by injecting a polishing liquid from a blast gun at an injection angle of 30 degrees or more and 60 degrees or less with respect to an axial direction of the rotating shaft sandwiching the insert base body rotatably. Is.

  The method for producing a surface-coated titanium carbonitride-based cermet cutting insert according to the thirteenth aspect of the present invention is the method for producing a surface-coated titanium carbonitride-based cermet cutting insert according to the twelfth aspect, wherein the wet blasting step is performed. And the said injection angle shall be 40 to 50 degree | times, It is characterized by the above-mentioned.

  And the manufacturing method of the surface-coated titanium carbonitride-based cermet cutting insert according to the fourteenth aspect of the present invention is the surface-coated titanium carbonitride-based cermet cutting according to any one of the tenth to thirteenth aspects. In the insert manufacturing method, honing is performed on the surface of the cutting edge portion of the insert base body at the stage before the covering step after the wet blasting step.

  The method for producing a surface-coated titanium carbonitride-based cermet cutting insert according to the fifteenth aspect of the present invention is the method for producing a surface-coated titanium carbonitride-based cermet cutting insert according to the fourteenth aspect, wherein the honing is performed. The surface roughness of the cutting edge of the insert substrate is 0.1 μm or less in terms of arithmetic average roughness Ra at a cutoff value of 0.08 mm.

  And the manufacturing method of the surface-coated titanium carbonitride-based cermet cutting insert according to the sixteenth aspect of the present invention is the surface-coated titanium carbonitride-based cermet cutting according to any one of the tenth to fifteenth aspects. In the insert manufacturing method, at least one selected from IVa group element, Va group element, VIa group element, Al, Si, Y, Mn, Ni, and S in the periodic table as the hard coating layer in the coating step. One or more layers of a compound comprising a seed element and at least one element selected from carbon, nitrogen, oxygen, and boron are formed by physical vapor deposition. It is.

  And the manufacturing method of the surface-coated titanium carbonitride-based cermet cutting insert according to the seventeenth aspect of the present invention is the manufacturing method of the surface-coated titanium carbonitride-based cermet cutting insert according to the sixteenth aspect. Among the hard coating layers, at least one layer is formed of a TiAlN layer.

  The method for producing a surface-coated titanium carbonitride-based cermet cutting insert according to the eighteenth aspect of the present invention is the method for producing a surface-coated titanium carbonitride-based cermet cutting insert according to the sixteenth aspect. The hard coating layer is formed of one layer or two or more layers selected from Ti carbide, nitride and carbonitride, and has a total film thickness of 0.5 to 15 μm. It is characterized by.

  The manufacturing method of the surface-coated titanium carbonitride-based cermet cutting insert according to the nineteenth aspect of the present invention is the method of manufacturing the surface-coated titanium carbonitride-based cermet cutting insert according to the eighteenth mode. As the hard coating layer, from the side of the insert substrate, a TiN layer having a thickness of 0.1 to 1.0 μm, a TiCN layer having a thickness of 0.5 to 5.0 μm, and a thickness of 0.1 to 1.0 μm The TiN layer is formed in that order.

    The surface-coated TiCN-based cermet cutting insert of the present invention is a sintered body comprising a titanium carbonitride-based cermet having a through-hole for attachment to a tool body, a flank, a honing portion, a rake face, and a chip breaker on the rake face. In the surface-coated titanium carbonitride-based cermet cutting insert formed by coating the insert base constituted by the hard coating layer by the physical vapor deposition method (PVD method), at least the tool main body among the inner surfaces of the mounting through holes A support tool contact surface in contact with a support tool as an attachment means is a surface not covered with the hard coating layer, and the support tool contact surface is 0.2 μm in arithmetic mean roughness Ra at a cutoff value of 0.08 mm. Therefore, the friction between the support as an attachment means to the tool body and the support contact surface of the through hole is This prevents the occurrence of slippage of the insert relative to the support, which prevents the insert from causing abnormal vibration and micro-vibration even in high-load cutting and intermittent cutting, and prevents the cutting edge from being damaged. In addition to improving the chipability and the finished surface accuracy of the work material, it is possible to suppress the occurrence / progress of cracks and breakage from the contact surface of the through hole support. Here, when a hard coating layer is formed on the support contact surface of the through hole by the PVD method, the hard coating layer is generally harder than the cermet of the TiCN-based insert base, but is easily broken by an instantaneous impact load. However, during high-load cutting or intermittent cutting, there is a risk that cracks and breakage may easily occur from the support contact surface of the insert at the moment when a large impact is applied from the support tool to the support contact surface of the insert. In the invention, the support contact surface of the through hole is not covered with a hard coating layer, so that it exhibits excellent fracture resistance without causing such problems even during high-load cutting and intermittent cutting. can do. Furthermore, when a hard coating layer is formed on the support contact surface of the through hole by the PVD method, wear of support tools (L-shaped levers, screws, eccentric pins, etc.) that contact the support contact surface progresses early. However, since the life of the support may be shortened, in the present invention, since the support contact surface of the through hole is not covered with the hard coating layer, such a problem does not occur and the support The lifetime can be extended. On the other hand, in the surface-coated insert of the present invention, the flank of the insert base and the chip breaker have a surface roughness of 0.2 μm or less in terms of the arithmetic average roughness Ra at a cutoff value of 0.08 mm. At the same time, since compressive residual stress is applied to the hard phase of the surface part of the rake face at the same time, as a result, excellent fracture resistance is ensured and excellent finished surface accuracy is achieved over a long period of time. It can be maintained over use.

  Further, according to the method of manufacturing the surface-coated TiCN-based cermet cutting insert of the present invention, at least the surface of the insert base manufactured by the sintering method is wet blasted in the region excluding the support contact surface of the mounting through hole. The surface of the flank and the chip breaker and at least the rake face is maintained by applying the treatment while leaving the sintered skin on the surface of the support tool contact surface and maintaining the surface roughness at an appropriate roughness. By adjusting the residual stress of the hard phase within a predetermined range and forming a hard coating layer by physical vapor deposition on the surface of the insert base body except the support contact surface. Thus, even in high-load cutting, it is possible to suppress the occurrence and progress of cracks and breakage from the support contact surface of the through hole, and it has excellent fracture resistance, The surface coating TiCN based cermet cutting insert raised surface accuracy good, can be obtained reliably and stably.

It is a perspective view which shows an example of the cutting insert which is an application object of this invention. It is a figure which shows a part of cutting insert shown by FIG. 1, and is a typical expanded sectional view in the XX line of FIG. It is a figure for showing the through hole for attachment in the cutting insert shown by FIG. 1, and is a typical expanded sectional view in the YY line of FIG. It is a figure which shows the attachment form to the tool main body of the cutting insert which is the application object of this invention, (a) is sectional drawing of the insert attached to a tool main body using an L-shaped lever as a support tool, (b) ) Is a cross-sectional view of an insert to be attached to a tool body using a screw as a support and its attachment form. It is a schematic diagram for demonstrating an example of the wet blast process applied in the manufacturing method of this invention.

  Hereinafter, the present invention will be described in more detail.

An example of the shape of the surface-coated TiCN-based cermet cutting insert of the present invention is shown in FIGS.
The insert 1 to which the present invention is applied has a through hole 8 for attachment to a tool body, a flank 2, a honing portion (cutting edge portion) 3, a rake face 4, The rake face 4 is provided with a chip breaker portion 5 formed by a mold, that is, a chip breaker portion 5 to which a die shape at the time of press molding is transferred. The insert of the present invention basically includes a hard phase mainly composed of Ti carbide or nitride or carbonitride, and a metal bonded phase mainly composed of one or two of Co and Ni. A TiCN-based cermet (sintered body) obtained by a sintering method comprising an insert base and the surface of the insert base (excluding the support contact surface in the mounting through-hole 8) of the periodic table Group IVa element, Group Va element, Group VIa element, Al, Si, Y, Mn, Ni, S and at least one element selected from carbon, nitrogen, oxygen, and boron A hard coating layer composed of one or two or more compounds composed of the above elements is coated by physical vapor deposition (PVD method). And the support tool contact surface of the said through-hole is comprised by the surface which is not coat | covered with the said hard coating layer, and the surface roughness of the support tool contact surface is 0. 0 in arithmetic mean roughness Ra in the cutoff value 0.08mm. The rough surface has a roughness exceeding 2 μm. On the other hand, the flank and chip breaker in the insert substrate have a smooth surface with an arithmetic average roughness Ra of 0.2 μm or less at a cutoff value of 0.08 mm, and at least the rake surface in the insert substrate. The residual stress of the hard phase on the surface of the material is set to 450 MPa or more by compression.

  Further, with respect to the insert to which the present invention is applied, a specific mode of attachment to the tool body will be described with reference to FIGS. 3 and 4. As described above, the insert 1 has the through-hole 8 for attachment. In the mounting through-hole 8, a support as an attaching means for attaching to the tool body 9, for example, an L-shaped lever 9A as shown in FIG. 4A, or FIG. A screw 9B as shown and an eccentric pin (not shown) are inserted and attached to the tool body 9. Then, at least a part of the inner surface of the through hole 8 for attaching the insert 1 comes into contact with a support such as an L-shaped lever 9A, a screw 9B, and an eccentric pin of the tool body 9. Thus, the part which contacts the support part as an attachment means to the tool main body 9 among the inner surfaces of the through-hole 8 for attachment of the insert 1 is called 8 A of support tool contact surfaces.

  The inserts used in the present invention include substantially flat plate inserts such as approximately square, triangle, rhombus, hexagon, and round, triangular grooving or threading inserts, inserts for various types of end mills that have a replaceable edge, or thick verticals. Various types such as blade inserts can be used, and the negative and positive shapes can be applied without any particular problem.

In the present invention, as described above, in the surface-coated TiCN-based cermet cutting insert having a through hole for attachment to the tool body, the support contact surface in the through hole is a surface on which a hard coating layer is not formed by the PVD method. And the surface roughness is a rough surface exceeding 0.2 μm in arithmetic average roughness Ra at a cutoff value of 0.08 mm.
As shown in FIG. 4, the surface of the through hole comes into contact with mounting means (supporting tool) such as a screw, L-shaped lever, or eccentric pin that is passed through the through hole, and the insert is fixed to the tool body by the frictional force thereof. If the surface roughness of the support tool contact surface of the through hole is 0.2 μm or less in arithmetic average roughness Ra at a cutoff value of 0.08 mm, the friction force on the contact surface with the support tool is not sufficient. For this reason, inserts cannot be held firmly and reliably under cutting conditions with constant high loads (fluctuating loads). As a result, chipping tends to occur and the finished surface accuracy is high. The surface roughness of the inner surface of the through hole should be a rough surface that exceeds 0.2 μm in terms of arithmetic average roughness Ra at a cutoff value of 0.08 mm. In addition, a rough surface of 0.3 μm or more is preferable.

  For example, as shown in FIG. 3, a tapered surface 8B is formed at the opening end of the mounting through hole 8, and the mounting support 9A (9B) is not in contact with the tapered surface 8B. In this case, the tapered surface 8B does not necessarily have to be a rough surface as described above. That is, as described above, Ra needs to have a rough surface of more than 0.2 μm, preferably 0.3 μm or more, among the inner surfaces of the mounting through-holes 8, which is at least means for attaching to the tool body. The surface of the portion that is determined by design to not contact the support is allowed to be a smooth surface of Ra 0.2 μm or less.

In addition, as the surface roughness of the through-hole inner surface (particularly the support contact surface) of the sintered insert made of TiCN-based cermet, a rough surface exceeding 0.2 μm is secured with an arithmetic average roughness Ra at a cutoff value of 0.08 mm. In order to do this, it is effective that the inner surface of the through hole is mainly composed of sintered skin. That is, by adjusting the sintering raw material powder and the sintering conditions, the surface roughness of the sintered body can be a rough surface exceeding Ra of 0.2 μm. Then, the inner surface of the through hole (particularly the support contact surface) of the sintered skin having such a rough surface is not smoothed by wet blasting, and the hard coating layer is not formed by the PVD method. As a cutting insert of the final product, by exposing the sintered skin directly to the inner surface of the through hole (particularly the contact surface of the support), an insert that satisfies the above conditions as the surface roughness of the inner surface of the through hole (particularly the contact surface of the support) Can be obtained.
Here, the sintered skin means a surface skin that has been sintered in the manufacturing process of the insert substrate, that is, a rough surface skin that has not been ground with a diamond grindstone or the like.

Here, in the surface covering insert of the present invention, the support contact surface of the through hole not only satisfies the surface roughness condition as described above, but is finally a surface that is not covered with the hard coating layer by the PVD method. It is necessary to. The reason is as follows.
That is, when a hard coating layer is formed on the support contact surface of the through hole by the PVD method, the hard coating layer is harder than the cermet of the TiCN-based insert substrate, but is easily broken by an instantaneous impact load. Therefore, even when the contact surface of the support on the inner surface of the through hole is adjusted to a predetermined surface roughness and minute vibrations during cutting are suppressed, the support from the support to the insert is supported during high-load cutting or intermittent cutting. When a large impact is momentarily applied to the contact surface, the impact is not absorbed and directly applied to the surface layer of the support contact surface of the insert, and the surface layer of the support contact surface is likely to crack or break. There is a fear. Further, when a hard coating layer is formed on the support contact surface of the through hole by the PVD method, since the coating layer is harder than the cermet of the TiCN-based insert base, the support device that contacts the support contact surface Wear of (L-shaped lever, screw, eccentric pin, etc.) progresses early and the life of the support may be shortened. Incidentally, the hardness of the TiCN-based cermet is generally 91 to 93HRA (about 1500 to 1900HV in terms of Vickers hardness), whereas the hardness of the hard coating layer by a general PVD method is about 3000HV. .
However, in the present invention, the support contact surface of the through hole is not covered with the hard coating layer, so that the surface of the cermet substrate is exposed on the support contact surface, and the cermet substrate has a higher load than the hard coating layer. Even during the cutting process and the intermittent cutting process, it is possible to absorb a large momentary impact to some extent, so that excellent fracture resistance can be exhibited without causing the above-described problems.

In the present invention, the flank of the insert substrate made of TiCN-based cermet and the surface roughness of the chip breaker are smooth surfaces with an arithmetic average roughness Ra of 0.2 μm or less at a cutoff value of 0.08 mm.
Here, when the inner surface of the through hole is mainly composed of sintered skin as described above, the flank of the insert base and the surface roughness of the chip breaker are naturally rough, but the flank is rough. In some cases, the accuracy of the finished surface is reduced, and if the chip breaker is rough, the chipping resistance is deteriorated. To prevent these, the flank face of the insert and the surface roughness of the chip breaker are cut. It is necessary to provide a smooth surface with an arithmetic average roughness Ra of 0.2 μm or less at an off value of 0.08 mm.
The smoothing of the flank face of the insert substrate mainly contributes to the improvement of the finishing accuracy of the work material, and the reduction of the surface roughness of the chip breaker mainly contributes to the improvement of the fracture resistance. If the surface roughness is a rough surface with an arithmetic average roughness Ra of 0.28 μm at a cutoff value of 0.08 mm, the finishing accuracy and fracture resistance of the work material tend to decrease. Therefore, in the present invention, the flank face of the insert base and the surface roughness of the chip breaker are defined as an arithmetic average roughness Ra of 0.2 μm or less at a cutoff value of 0.08 mm.
As described above, the surface roughness of the inner surface of the through-hole (particularly the support contact surface) of the sintered skin insert base is more than 0.2 μm in Ra, preferably, Ra is maintained at 0.3 μm or more. In order to smooth the surface roughness of the flank and the chip breaker to Ra 0.2 μm or less, a wet blasting process may be performed on the surface of the substrate except for the inner surface of the through hole or its support member contact surface.

Note that the flank and chip breaker surface roughness defined in the present invention are values for the surface of the insert substrate before the formation of the hard coating layer by the PVD method. When a hard coating layer is formed by the PVD method and the surface roughness is measured from above the hard coating layer, the surface roughness may be larger than the surface of the insert substrate before coating. When the flank face of the insert base and the surface roughness before forming the hard coating layer of the chip breaker are 0.2 μm or less in arithmetic average roughness Ra at a cutoff value of 0.08 mm, a hard coating layer was formed by the PVD method. The roughness of the later flank and chip breaker surface (hard coating layer surface) varies depending on the thickness of the hard coating layer and the PVD conditions, but is usually an arithmetic average roughness Ra of 0.08 mm at a cutoff value of 0.08 mm. It is about 25 μm or less. And if the roughness Ra of the hard coating layer surface is about 0.25 μm or less, it has been confirmed that the finishing accuracy and fracture resistance of the work material are not impaired.
In addition, although the granular projection called a droplet may arise in the coating layer surface in the hard coating layer by an arc ion plating method, the arithmetic average roughness Ra of the insert surface in this application does not have a droplet. It is the surface roughness measured at a location.

  In the present invention, the surface roughness is measured by arithmetic average roughness Ra at a cutoff value of 0.08 mm in accordance with JIS B0601-1994 (2001). The cut-off value of 0.08 mm is the microscopic state of the cutting insert surface that affects the quality of the cutting surface, and occurs during the density variation of the green compact before sintering and during sintering. This is for removing the influence of the undulation phenomenon (swelling component) on the sintered skin of the insert base due to the sintering deformation or the like.

Furthermore, in the present invention, in order to further improve the fracture resistance, a compressive residual stress of 450 MPa or more is applied to the hard phase of at least the rake face of the insert substrate. Here, when the compressive residual stress of the hard phase on the surface portion of the rake face of the insert substrate is less than 450 MPa, the effect of improving the fracture resistance against a high load acting at the time of cutting is small, so that the fracture resistance is increased. The residual stress was determined as described above. The residual stress of the hard phase in the surface portion of at least the rake face of the insert substrate is preferably 600 MPa or more. The application of compressive residual stress to the hard phase of the surface portion of at least the rake face of the insert base is achieved by wet blasting for smoothing the flank face of the insert base and the surface of the chip breaker as described above. be able to.
In addition, the residual stress of the hard phase on the surface of the normal sintered skin that is not subjected to wet blasting is about 100 MPa or less in compression, and even about 300 MPa even in the case of TiCN-based cermets whose surface composition is changed from the inside. However, by performing wet blasting according to the method of the present invention (however, excluding at least the penetrating support contact surface), at least the rake face in the region excluding at least the penetrating support contact surface is inserted. The value of the compressive residual stress can be 450 MPa or more.

Here, the value of the residual stress applied to the hard phase of the surface portion of the insert base in the present invention is “X-ray evaluation of residual stress” issued by Yokendo Co., Ltd. (Keisuke Tanaka, Kenji Suzuki, Akiba It is a value measured by an X-ray diffractometer using the well-known sin ² Ψ method described in the beginning of Chapter 6 (P99-105) of Yoshiaki.
Furthermore, regarding the sin ² Ψ measurement range, the measurement was performed by developing the parallel tilt method at 5 to 6 points at equal intervals in a range selected from 0 to 0.5 to 0 to 0.75.
The X-ray diffractometer used for the measurement was PAN alytical manufactured by Spectris Co., Ltd.
In X ′ Pert PRO MPD, CuKα ray was used as the X-ray source.
For the measurement of residual stress, a diffraction peak on the (422) plane of the hard phase having an NaCl type crystal structure was used.
The residual stress calculation software used for the measurement was X ′ Pert High Score Plus, and the calculation was performed using 475 GPa as the Young's modulus of the hard phase and 0.200 as the Poisson's ratio.

Furthermore, at the initial stage of cutting using the insert, the honing part at the tip of the cutting edge contacts the cutting surface of the work material to form the cutting surface, and then the wear of the cutting edge develops. If it comes, the area | region which contacts the cutting surface will shift to the flank side. Therefore, the insert base is subjected to wet blasting for smoothing and applying residual stress as described above, and then subjected to a honing process using a wet brush or the like on the tip of the insert base. It is desirable to make the surface roughness of the formed honing part smaller than other parts. Specifically, if the surface roughness of the honing portion formed at the tip of the cutting edge is 0.1 μm or less in arithmetic average roughness Ra at a cutoff value of 0.08 mm, the fracture resistance is further improved, and the initial cutting stage Thus, a good glossy finished surface can be formed on the work material. Here, when the surface roughness of the honing portion (the surface roughness of the hard coating layer of the honing portion) is measured after the hard coating layer is formed by the PVD method, the roughness is determined based on the roughness before the formation of the hard coating layer. May be slightly rough. However, when the honing part is processed with a wet brush or the like before the hard coating layer is formed and the surface roughness is appropriately finished as described above, the surface roughness of the honing part after the hard coating layer is formed. Ra is about 0.25 μm or less, and if it is this level, the fracture resistance can be sufficiently improved as described above.
As will be described later, the honing process for the cutting edge portion is most preferably performed after the wet blasting process. However, even when the wet blasting process is performed after the honing process, the effects of the present invention can be obtained. In addition, when a predetermined honing dimension is processed only by wet blasting, such as when the honing dimension is relatively small, honing processing by a brush or the like is not performed, and the honing process may be combined with the wet blasting process. Needless to say, the effect of the present invention can be obtained also in that case.

Furthermore, in the surface-coated titanium carbonitride-based cermet cutting insert of the present invention, at least the region of the surface of the insert base made of titanium carbonitride-based cermet excluding the support contact surface of the through hole is hard-coated by the PVD method. A layer is formed. Such a hard coating layer formed by the PVD method is generally denser and harder than the cermet of the substrate, and thus can improve wear resistance. Further, if PVD is applied to the surface of the insert base body in which the flank and the chip breaker are smoothed to Ra 0.2 μm or less by wet blasting as described above, the surface of the flank and the hard coating layer by PVD on the chip breaker is also Ra0. Since it is a smooth surface of about 25 μm or less, excellent chipping resistance and finished surface accuracy can be ensured. However, as described above, if the support contact surface of the through hole is also covered with the hard coating layer by the PVD method, the hardness of the hard coating layer is much higher than that of the cermet of the substrate as described above. Due to the high nature of being easily broken by an instantaneous impact load, cracks and breakage are likely to occur from the support contact surface of the insert, and support tools that contact the support contact surface (L-shaped levers, screws, eccentricity) In the present invention, a hard coating layer is formed by the PVD method on the support contact surface or the inner surface of the through hole including the support device. Not to do.
The thickness of the hard coating layer formed by the PVD method on the surface of the insert substrate excluding the support contact surface or the inner surface of the through hole including the support is not basically limited, but is usually 0.5 to It is desirable to be about 15 μm. When the thickness of the hard coating layer is less than 0.5 μm, the wear resistance is not sufficient. On the other hand, when the thickness of the hard coating layer exceeds 15 μm, the hard coating layer may be easily peeled off.

The hard coating layer formed on the surface of the insert substrate by the PVD method is at least one selected from IVa group element, Va group element, VIa group element, Al, Si, Y, Mn, Ni, and S in the periodic table And one or two or more layers of a compound comprising at least one element selected from carbon, nitrogen, oxygen and boron.
Here, the specific material of the hard coating layer by the PVD method may be selected from the above. When AlCrN or the like is particularly effective and when the tool life is important, it is desirable that at least one layer is composed of a TiAlN layer. Since such a TiAlN layer has high adhesion strength to the insert substrate and high heat resistance, it is possible to significantly extend the tool life by forming at least one of the hard coating layers as a TiAlN layer.
Further, when a finished surface of the work material is required, the hard coating layer is composed of one or more layers selected from Ti carbide, nitride, carbonitride having excellent welding resistance. In addition, it is desirable to select a hard coating having a total film thickness of 0.5 to 15 μm, and more specifically, when a hard coating layer by a PVD method is formed in a plurality of layers, From the side, a 0.1-1.0 μm thick TiN layer, a 0.5-5.0 μm thick TiCN layer, and a 0.1-1.0 μm thick TiN layer are coated in that order. Is desirable. With such a layer structure, since the affinity between the material constituting the hard coating layer and the work material (iron-based) is low, it is difficult for the welding phenomenon to occur during cutting, and a good work material finish surface. It is particularly suitable for inserts made of surface-coated titanium carbonitride-based cermets, which can obtain accuracy and often require a machined surface roughness.
Further, if the total film thickness of the hard coating layer composed of one layer or two or more layers selected from Ti carbide, nitride, and carbonitride is less than 0.5 μm, the wear resistance performance is not sufficient. If the film thickness exceeds 15 μm, it has been confirmed that the hard coating layer tends to be peeled off.
In addition, as PVD method here, various physical vapor deposition methods known conventionally, such as an arc ion plating method, a holo cathode method, sputtering method, etc. can be applied, and are not specifically limited. .

Next, the manufacturing method of the surface coating titanium carbonitride based cermet cutting insert by this invention is demonstrated.
The production method of the present invention basically comprises an insert substrate production process by a sintering method, a wet blast process, and a coating process for forming a hard coating layer by a PVD method, and preferably a wet blast process and a coating process. A honing process for the cutting edge portion is inserted between the processes, or between the insert substrate manufacturing process and the wet blast process. Accordingly, each of these steps will be described below.

Insert substrate manufacturing process:
The insert substrate manufacturing process may be the same as the manufacturing process of a sintered body (insert substrate) in manufacturing a conventional titanium carbonitride-based cermet cutting insert. That is, the titanium carbonitride-based cermet raw material powder is blended at a predetermined blending ratio, press-molded into a cermet substrate shape, and the resulting green compact is heated and sintered under predetermined conditions. However, in this sintering stage, as already mentioned, the surface roughness of the sintered body is more than 0.2 μm in arithmetic mean roughness Ra at a cutoff value of 0.08 mm, preferably more than Ra 0.3 μm. It is desirable to appropriately adjust the blending ratio of the raw material powder, the sintering temperature, the sintering atmosphere, the cooling conditions, etc. so as to be rough. In addition, a chip breaker to which a die shape at the time of press molding is transferred is formed on the rake face of the insert base thus obtained. Also, the seating surface when attaching the insert to the tool body may have a grinding surface with a grindstone, but the flank surface is usually not ground and is formed by a die during press molding It is.

Wet blasting:
For the insert substrate, which is a sintered body obtained as described above, the surface of the insert substrate excluding the inner surface of the through hole for mounting (particularly the contact surface of the support) is smoothed, and the compressive residual stress is further increased. Wet blasting is performed for the purpose of imparting.
Conventionally, shot peening (shot blasting), drive blasting, etc. are known as insert surface treatment means, but shot peening (shot blasting) using relatively large steel balls or ceramic balls is a processing energy. Is excessive, there is a risk that coarse cracks may occur on the surface and inner surface of the insert base. Drive blasting, which blasts the insert surface with two types of fluids (powder flow and air flow), is more energy efficient than wet blasting. Therefore, there is a problem that surface smoothing and compressive stress cannot be sufficiently performed, and further, the sprayed abrasive is likely to bite and remain on the treated surface.
Therefore, in the present invention, wet blasting is adopted as a means for smoothing the surface of the insert base body and applying compressive residual stress, except for the inner surface of the through hole for mounting (particularly, the contact surface of the support) without incurring the above-mentioned adverse effects doing.
By using wet blasting, a complicated shape (for example, a shape in which one surface is constituted by a set of a plurality of curved surfaces, without giving the insert substrate surface defects such as coarse cracks at the time of manufacturing that have occurred in the prior art. ) And the insert substrate excluding at least the inner surface of the through hole for mounting (particularly the support contact surface thereof) without damaging the shape of the insert breaker and the chip breaker portion having a three-dimensional shape molded by a mold. As a result, it was possible to smooth the surface of the surface portion and to further improve the performance of the cutting insert by applying compressive residual stress.

  Here, wet blasting is a process in which a polishing liquid, which is a liquid (generally water) containing a jet abrasive, is sprayed onto a workpiece to give a compressive residual stress or to polish a surface. As a spray abrasive for such wet blasting, various materials such as alumina, silicon carbide, zirconia, resin, and glass can be used as long as they are hard fine-grained media. As for, the center particle diameter at the time of initial charging is desirably about 1 to 100 μm, and about 10 to 50 μm is more preferable in consideration of both productivity and quality. Further, as an injection condition, for example, when alumina is used as a medium, a blast gun is prepared by adjusting the polishing liquid by containing the medium so that it is in the range of 15 to 60% by weight in a state mixed with the liquid (water). It is desirable to inject the compressed air supplied to the pressure, that is, the injection pressure within the range of 0.05 to 0.5 MPa, preferably 0.1 to 0.3 MPa.

  The shape of the abrasive used for wet blasting is preferably polygonal abrasive. Here, as the alumina abrasive, a spherical alumina abrasive is generally used. However, the polygonal alumina abrasive has a square shape formed by a cleavage plane as compared with the spherical alumina abrasive. Because of the shape having the cutting edge, the grinding force is large and the smoothing effect is also high. On the other hand, when the abrasive is spherical, it is suitable for applying residual stress, but the grinding action is weak and a long time is required for wet blasting to finish the insert surface to a specified surface roughness. Thus, not only productivity is deteriorated, but also defects such as cracks due to excessive treatment of wet blast may occur on the insert surface.

Furthermore, the outline of the wet blasting process in the present invention will be described with reference to FIG.
In FIG. 5 (a), the entire base surface is sintered and the insert base 10 is sandwiched and held by a pair of rotary shafts 12 that can rotate about the axis (O), while rotating about the axis, With respect to the axial direction of the rotation axis (O), for example, the polishing liquid G is sprayed onto the surface of the insert base 10 from two blast guns 14 facing each other having a spray angle θ of 45 degrees, one by one. By performing the wet blasting process, the entire surface of the insert base 10 can be uniformly processed except at least the inner surface of the through hole for attachment (including the support contact surface).

Here, a large-diameter sealing portion 12A is formed at the tip of the rotary shaft 12, and this sealing portion 12A is brought into contact with the opening end of the insert base mounting through hole 8 for mounting. Since injection of the wet blast polishing liquid onto the inner surface of the through hole 8 is prevented, the inner surface of the mounting through hole 8 is not subjected to wet blasting, and the surface state immediately after sintering is maintained. That is, the inner surface of the through hole including the support tool contact surface maintains a sintered skin having a predetermined surface roughness.
On the other hand, a smooth surface is formed on the flank surface of the insert base 10 and the surface of the chip breaker by wet blasting. Here, by adjusting the kind of the polishing liquid, the injection pressure, etc., the flank face of the insert base and the surface of the chip breaker satisfy the condition of an arithmetic average roughness Ra of 0.2 μm or less at a cutoff value of 0.08 mm. A smooth surface can be formed, and at the same time, a compressive residual stress of 450 MPa or more can be imparted to the hard phase of at least the rake face of the insert substrate 10.
As shown in FIG. 5 (b), when the injection angle θ of the blast gun 14 with respect to the axial direction of the rotation axis O is 30 degrees or more and 60 degrees or less, preferably 40 degrees or more and 50 degrees or less, the insert base body Uniform wet blasting can be performed on the entire surface of 10 (excluding the support contact surface of the through hole). In addition, as for the number of blast guns 14 to be used, two examples are shown in FIG. 5A, but one or more than one guns may be used depending on the shape of the insert base to be processed. good.

Further, in order to prevent the inner surface of the mounting through-hole 8 from being wet-blasted more reliably, as shown in FIG. 5C, the insert base 10 is interposed between the rotary shaft 12 that sandwiches the insert base 10 and the insert base 10. By interposing the masking member 18, it is possible to reliably maintain the inner surface of the mounting through hole 8 covered with the masking member 18 with the sintered skin having a predetermined surface roughness. That is, for example, when the rotating shaft 12 of the wet blast and the through hole 8 for mounting the insert base 10 cannot be arranged on the same axis line, or the insert base having a plurality of mounting through holes arranged at a distance, or the through through for mounting Insert bases with a shape that may cause wet blasting to be applied to the inner surface of the mounting through-holes by a normal holding method, such as when wet blasting is applied to an insert base having a non-circular cross-sectional shape such as an ellipse. On the other hand, if the masking member as described above is used, it is possible to reliably avoid the wet blasting process to the inner surface of the through hole.
As described above, by using the wet blasting apparatus having the above-described configuration, the individual injection conditions are appropriately set and the optimum wet blasting process is performed on the insert base having various shapes and chip breakers. It becomes possible.

  For example, as shown in FIG. 3, a tapered surface 8B is formed at the opening end of the mounting through hole 8, and the mounting support 9A (9B) is not in contact with the tapered surface 8B. In this case, the tapered surface 8B may be subjected to the wet blasting process as described above. That is, as described above, it is necessary to leave the sintered skin having a predetermined surface roughness among the inner surfaces of the mounting through-holes 8, at least the surface that comes into contact with the support that is the attachment means to the tool body. Any surface may be used, and it is allowed to perform wet blasting on the surface of the portion that is determined not to contact the support by design.

Honing process:
As already mentioned, after wet blasting, before the hard coating layer is formed by the PVD method, the tip of the insert base is subjected to honing with a wet brush or the like to form the tip of the tip. It is desirable to make the surface roughness of the honing part to be smaller than other parts. The specific honing method is basically the same as the honing of the cutting edge tip in conventional cutting insert manufacturing, for example, honing with an elastic grindstone, barrel, brush, etc. According to honing, a high-quality processed surface can be obtained, and various shapes of honing can be processed in a relatively short time. However, if a wet blast process is performed after the honing process, the honing part is processed again by the wet blast process, and the shape and size of the honing part may change, and the original cutting performance may not be exhibited.
Therefore, in the present invention, it is desirable to perform the honing treatment of the cutting edge portion by honing (preferably brush honing, more preferably wet brush honing) as a step after the wet blasting as described above. By performing honing of the cutting edge portion after wet blasting in this way, an insert that maintains excellent finished surface accuracy of the work material for a long time can be obtained. In addition, if wet brush honing is performed after wet blasting, it is possible to take advantage of wet brush honing and obtain a honing surface with good surface roughness and precisely controlled to a predetermined shape with high productivity. It becomes possible.
The honing process for the cutting edge is most preferably performed after the wet blasting process, but the effects of the present invention can be obtained even when the wet blasting process is performed after the honing process.
In addition, when the size of the honing to be processed is relatively small, the wet blasting process may also serve as the honing process without performing the honing process with a brush or the like because the honing process is performed only by the wet blasting process. . In that case, naturally, it has been confirmed that the effects of the present invention can be obtained.
In this honing process, it is desirable that the surface roughness of the honing part formed at the tip of the cutting edge of the insert base is 0.1 μm or less in terms of arithmetic average roughness Ra at a cutoff value of 0.08 mm. By appropriately adjusting the surface roughness Ra of the honing portion before forming the hard coating layer, the surface roughness Ra of the honing portion after forming the hard coating layer can be reduced to about 0.25 μm or less. If the surface roughness of the honing part is sufficient, the fracture resistance can be sufficiently improved as described above.

Coating process by physical vapor deposition (PVD method) (hard coating layer forming process):
After wet blasting, preferably after honing of the cutting edge tip, PVD method is used to form at least the surface of the insert base of the insert base except the support contact surface on the inner surface of the through hole for mounting. At least one element selected from the group consisting of element, Va group element, VIa group element, Al, Si, Y, Mn, Ni and S, and at least one element selected from the group consisting of carbon, nitrogen, oxygen and boron A hard film comprising at least one layer or multiple layers of a compound comprising an element is formed by coating.
Here, as the PVD method for forming the hard coating layer, a known physical vapor deposition method such as an arc ion plating method, a holo cathode method, or a sputtering method may be applied. However, in the case of the present invention, as described above, the inner surface of the through hole, particularly the contact surface of the support member, must be a sintered skin having a predetermined surface roughness even in the final product, and therefore the PVD method is applied to the insert substrate. In this case, the inner surface of the through hole or at least the support contact surface of the through hole is not covered with the PVD hard coating layer. For this purpose, vapor deposition by PVD may be performed, for example, with the through hole or at least the support contact surface inside the through hole covered with an appropriate masking member.

  Examples of the present invention will be described below together with comparative examples. The following examples are for explaining specific embodiments of the present invention and effects thereof, and the configurations and conditions described in the examples do not limit the technical scope of the present invention. Of course.

After the P30 grade TiCN-based cermet raw material powder having the following raw material blend composition is press-molded, it is sintered under the following conditions, and the sintered surface having various surface roughnesses by adjusting the sintering temperature and nitrogen atmosphere pressure. A sintered body (insert base body) made of a TiCN-based cermet having a surface and a shape and dimensions specified in ISO / DNMG150612 was produced.
Raw material composition:
All blended TiCN powder, WC powder, NbC powder, Co powder, and Ni powder having an average particle diameter of 0.5 to 2 μm so as to be 55 wt%, 20 wt%, 7 wt%, 9 wt%, and 9 wt%, respectively. Then, they were wet mixed in a ball mill for 24 hours and dried.
Sintering conditions:
(1) The temperature is raised from room temperature to 1200 ° C. at a rate of 10 ° C./min in a vacuum atmosphere of 10 Pa or less,
(2) Raise the temperature up to 1350 ° C. at a rate of 2.0 ° C./min in a vacuum atmosphere of 10 Pa or less,
(3) In a nitrogen atmosphere of 4.0 kPa to 0.1 kPa, the temperature is increased from 1350 ° C. to a predetermined sintering temperature (1450 to 1550 ° C.) at a rate of 2 ° C./min. For 60 minutes.
For the cutting edge, a nylon brush containing abrasive grains is used, and a waterfall type curved honing with a width measured from the rake face side of 0.09 mm and a width measured from the flank face side of 0.05 mm Was applied by wet processing.
By applying wet blasting to these insert bases using alumina having a center particle diameter of 40 μm as a spraying abrasive and using the wet blasting apparatus shown in FIG. 5A at the spraying pressure shown in Table 1. The TiCN-based cermet cutting inserts of the present invention (Inventions 1 to 8) were produced.
In the wet blast treatment, the jet polishing liquid was prepared such that the alumina of the jet polishing material was mixed with water so that the content of the polishing material in the polishing liquid was 30% by weight.
Further, in the wet blast processing apparatus shown in FIG. 5A, the spray angle θ is fixed at 45 °, and wet blasting is performed so that the entire surface of the insert substrate is processed except for a portion sandwiched and held by a pair of rotating shafts. Therefore, the inner peripheral surface of the through hole of the insert base is not subjected to wet blasting, and the sintered skin is maintained.
Further, a hard coating layer of a single TiAlN layer having an average film thickness of 1.5 μm was vapor-deposited on the surface of each insert substrate by an arc ion plating method which is a kind of PVD method. However, in this vapor deposition coating, the through hole portion of the insert base was previously covered with a masking member so that the hard coating layer was not formed on the inner surface of the through hole (the surface including the support tool contact surface). That is, the sintered skin was maintained about the inner surface of the through hole including the support tool contact surface.

  In the above process, the surface roughness of the inner surface of the through hole, the flank surface and the honing portion of the insert base of the present invention 1-8 before coating with the hard coating layer is in accordance with JIS B0601-1994 (2001). The arithmetic average roughness Ra was measured at a cutoff value of 0.08 mm. Similarly, the residual stress of the hard phase of the insert surface portion of the present invention 1 to 8 before coating with the hard coating layer was measured on the flat surface of the insert flank by the aforementioned X-ray diffractometer. Table 1 shows the measurement results of these residual stresses and surface roughness.

In the insert bases of the present invention 1 to 8, the rake face is a curved surface having a breaker, so that a flat surface necessary for X-ray diffraction measurement cannot be secured, and the residual stress of the rake face is directly measured. However, in the first embodiment, since the processing is basically performed so that the same action is applied to the flank and the rake face by setting the injection angle at the time of wet blasting to 45 °, the rake face, particularly the flank face. Land part near the cutting edge and the bottom of the breaker located almost perpendicular to the cutting edge (residual stress value at the rake face near the cutting edge and the deepest bottom of the breaker curved in a concave shape is important for improving fracture resistance) Therefore, the residual stress of the insert substrate is represented by the residual stress measured for the flank.
Also, the surface roughness of the rake face (breaker bottom) was almost the same as that of the flank because the spray angle during wet blasting was 45 °. The surface roughness was represented by the surface roughness measured for the flank.

  Furthermore, the surface roughness of the flank, honing part, and inner surface of the through-hole is the same as described above for the surface-coated insert after the formation of the hard coating layer on the surface of the insert substrate by the PVD method except for the inner surface of the through-hole. The measurement results are also shown in Table 1.

For comparison, a surface-coated insert manufactured without applying wet blasting to a cutting insert base having the same composition, shape, and dimensions as the inserts of the present inventions 1 to 8 is prepared as Reference Example 1. The surface-coated inserts that were subjected to the same wet blast treatment as that of the inserts of the present invention 1 to 8 and also subjected to the wet blast treatment on the inner surface of the through holes were produced as Comparative Examples 1 and 2.
Further, with respect to the insert substrate (after wet blasting) manufactured in the same manner as Example 4 of the present invention, the entire surface of the insert substrate including the inner surface of the through hole including the support contact surface is PVD as described above. A surface coating insert of Comparative Example 3 was obtained by applying an arc ion plating method as a method and depositing a hard coating layer of a single TiAlN layer having an average thickness of 1.5 μm. That is, the surface covering insert of Comparative Example 3 is an example in which a hard coating layer is also formed on the inner surface of the through hole.
About these comparative examples 1-3 and the reference example 1, similarly to this invention 1-8, the residual stress in the flat surface of the flank before hard coating layer formation was measured with the X-ray-diffraction apparatus, and hard coating layer The surface roughness of the through hole inner surface, the flank surface, and the honing portion before and after the formation was measured with an arithmetic average roughness Ra at a cutoff value of 0.08 mm in accordance with JIS B0601-1994 (2001). The residual stress values and surface roughness values measured for these comparative examples and reference examples are also shown in Table 1.

According to Table 1, if the wet blast spray pressure on the surface of the insert base (flank and chip breaker) is increased, there is an effect of increasing the compressive residual stress, but if the spray pressure is higher than a predetermined range, Conversely, it can be seen that the surface roughness increases and the smoothness tends to decrease slightly.
In addition, the surface roughness of the honing part subjected to honing with a nylon brush is as smooth as 0.06 μm. However, when this surface is subjected to wet blasting under the conditions of the present invention, the surface roughness becomes large conversely, It turns out that smoothness falls.
In addition, wet blasting is not performed on the inner surface of the through hole of the surface-coated inserts of the present invention 1 to 8 and Reference Example 1, and the hard coating layer is not coated, so that the sintered skin remains. Moreover, the surface coating insert of Comparative Example 3 is not subjected to wet blasting on the inner surface of the through hole, but has a hard coating layer formed by the PVD method.

Next, a cutting test was performed under the following conditions in a state where each of the above surface-coated inserts was fixed to the tip of the cutting tool with an L-shaped lever shown in FIG.
<< Cutting Test 1 >>
Work material: Square material of JIS-SCM440,
Cutting speed: 260 m / min,
Feed: 0.5mm / rev,
Cutting depth: 2mm
Wet intermittent cutting of
The maximum number of impacts was 2000, and the number of impacts until a defect occurred was evaluated.
<< Cutting Test 2 >>
Work material: JIS-S10C round bar, cutting speed: 400 m / min,
Feed; 0.6mm / rev,
Cutting depth: 3.5mm
Wet continuous cutting of
The actual cutting time until cutting edge replacement was evaluated, and the cutting surface (finished surface) at the time of cutting edge replacement was also observed.
Table 2 shows the number of impacts until a defect occurs in the cutting tests 1 and 2, the actual cutting time until cutting edge replacement, and the cutting surface condition at the time of cutting edge replacement.
The actual cutting time until the cutting edge replacement is the time until the end of cutting when the finished surface deteriorates, and when the finished surface is maintained, the flank surface is maintained. The time until the wear width reached 0.4 mm was taken. This is because when the flank wear width grows to exceed 0.4 mm, it becomes impossible to maintain the machining dimensional accuracy in high feed cutting in which a high load acts.

According to Table 2, it can be seen that Reference Example 1 which was not subjected to wet blasting caused defects at 284 impacts and was inferior in fracture resistance.
The surface roughness of the flank and the chip breaker is the same as that of the present invention. However, Comparative Examples 1 and 2 where the surface roughness of the inner peripheral surface of the through hole is 0.2 μm or less are the same as those in Reference Example 1. Similarly, it is inferior in chipping resistance. In particular, in Comparative Example 1, in addition to the chipping of the cutting edge, damage traces were also found on the support tool contact surface on the inner surface of the through hole, so that abnormal vibration generated during cutting was supported. It is considered that the tool contact surface was damaged, and as a result, the fixing of the insert to the tool body became more uncertain, and the cutting edge was lost early. Furthermore, these inserts were interrupted in a short time due to deterioration of the finished surface even in wet continuous cutting.
Moreover, in the comparative example 3 which coat | covered the inner surface of the through-hole of the sintered skin with the hard coating layer, damage occurred from the surface of the hard coating layer on the support tool contact surface of the inner surface of the through-hole by wet intermittent cutting, and the cutting was completed. Furthermore, even in wet continuous cutting, cutting was completed in a short time due to white turbidity and chatter of the finished surface, but this was also because the fixing of the insert to the tool body became uncertain due to defects in the hard coating layer surface of the support contact surface it is conceivable that.
On the other hand, the surface roughness of the inner surface of the through hole exceeds 0.2 μm, and the surface roughness of the flank and chip breaker is reduced by wet blasting to give compressive residual stress to the hard phase of the rake surface. Furthermore, the inventive products 1 to 8 coated with a hard coating layer by the PVD method except for the inner surface of the through-hole showed excellent finished surface accuracy and long life without causing defects.

After a raw material powder of P20 grade TiCN-based cermet having the following raw material blending composition is press-molded, it is sintered under the following conditions, and an insert base body having a through hole having a shape and dimensions specified in ISO / TNMG160412 (sintered body) )created.
Raw material composition:
All of TiCN powder, WC powder, TaC powder, Mo ₂ C powder, Co powder, and Ni powder having an average particle diameter of 0.5 to ₂ μm were 56 wt%, 15 wt%, 5 wt%, 10 wt%, and 7 wt%, respectively. , 7 wt%, and wet mixed in a ball mill for 24 hours and dried.
Sintering conditions:
(1) The temperature is raised from room temperature to 1200 ° C. at a rate of 10 ° C./min in a vacuum atmosphere of 10 Pa or less,
(2) Raise the temperature to 1350 ° C. at a rate of 2 ° C./min in a vacuum atmosphere of 10 Pa or less,
(3) In a 2.0 kPa nitrogen atmosphere, the temperature was increased from 1350 ° C. to a predetermined sintering temperature (1500 ° C.) at a rate of 2 ° C./min, and then maintained at the sintering temperature for 60 minutes in the same atmosphere.
These cutting inserts were subjected to the same brush honing treatment and wet blasting treatment as in Example 1 in the order of steps and treatment conditions shown in Table 3.
Further, a hard coating layer of a single TiAlN layer having an average film thickness of 1.5 μm is vapor-deposited on the surface of each insert substrate by an arc ion plating method which is a kind of PVD method. Twelve surface-coated inserts were made. However, in the vapor deposition coating, the through hole portion of the insert base was previously covered with a masking member so that the hard coating layer was not formed on the inner surface of the through hole (the surface including the support tool contact surface). That is, the sintered skin was maintained about the inner surface of the through hole including the support tool contact surface.
For comparison, an insert that performs only brush honing and does not perform wet blasting is prepared as Reference Example 2, and under the same conditions as the present invention, brush honing and wet blasting are performed. Furthermore, the insert which performed the wet blast process also to the inner surface of the through hole was produced as Comparative Examples 4 and 5.
About the surface covering inserts of the present inventions 9 to 12, Reference Example 2, and Comparative Examples 4 and 5, as in Example 1, the surface roughness of each part at the stage of the insert substrate before coating with the hard coating layer Table 3 shows the results of measuring the residual stress and the surface roughness of each part of the surface-coated insert after coating with the hard coating layer.

In the present inventions 9 to 12, by performing wet blasting, the surfaces of the insert base (flank and chip breaker) all show high compressive residual stress of 450 MPa or more, and the surface roughness of the flank and chip breaker is All were Ra: 0.2 μm or less.
However, the present inventions 11 and 12, which have been subjected to the brush honing treatment after the wet blasting treatment, greatly improve the surface roughness of the honing portion as compared with the present inventions 9 and 10 which have been subjected to the wet blasting treatment after the brush honing treatment. You can see that
In Reference Example 2 in which only the brush honing process was performed and the wet blast process was not performed, the value of the compressive residual stress on the surface (flank and chip breaker) was smaller than that of the present invention 9-12.
Further, although the values of the compressive residual stress on the surfaces (flank and chip breaker) of Comparative Examples 4 and 5 were almost the same as those of the present invention, the inner surface of the through hole was obtained by performing wet blasting on the inner surface of the through hole. The surface roughness was reduced to Ra: 0.17 μm.
The surface roughness of the inner surface of the insert through hole was in the range of Ra: 0.32 to 0.34 μm in both of the present inventions 9 to 12 and Reference Example 2.

Next, a cutting test was performed under the following conditions in a state where each of the various cutting inserts was fixed to the tip of the cutting tool with the L-shaped lever shown in FIG.
<< Cutting Test 3 >>
Work material: Square material of JIS-SNCM439,
Cutting speed: 240 m / min,
Feed; 0.6mm / rev,
Cutting depth: 2mm
Wet intermittent cutting of
The number of impacts until a defect occurred was evaluated.
<< Cutting Test 4 >>
Work material: JIS-SUJ2 round bar,
Cutting speed: 450 m / min,
Feed; 0.6mm / rev,
Cutting depth: 3mm
Wet continuous cutting of
The cutting surface at the start of cutting after a cutting time of 0.2 minutes was observed.

The present inventions 9 to 12 subjected to the wet blast treatment all showed excellent fracture resistance, but in particular, the present invention 11 which reduced the surface roughness of the honing portion by performing the brush honing treatment after the wet blast treatment. , 12 showed even better results.
In contrast, in Reference Example 2 where the flank and chip breaker were not wet blasted, and in addition to the flank and chip breaker, wet blasting was performed to the inner surface of the through hole, and the surface roughness of the inner surface of the through hole was reduced. In Comparative Example 4 in which Ra was reduced to 0.17 μm, it was found that the number of impacts up to the defect was very small and the defect resistance was poor. Further, in Comparative Example 5 in which wet blasting was similarly performed to the inner surface of the through hole, the insert was lost from the support tool contact surface of the inner surface of the through hole, and the cutting was completed in a short time.
In addition, in SUJ2 high-speed high-feed cutting where it is difficult to obtain a good machined surface, Reference Example 2 and the present inventions 11 and 12 in which the surface roughness of the honing part is small provide a glossy and good finished surface from the cutting start stage. However, although it was possible to obtain a normal finished surface free from the occurrence of stuffiness and white turbidity, the cutting surfaces according to the present invention 9 and 10 did not provide a glossy finished surface.
Furthermore, in Comparative Examples 4 and 5 in which the surface roughness of the inner surface of the through hole was reduced, it was a finished surface with chatter from the beginning of cutting.

  From the results shown in Tables 1 to 4 above, the inner surface (the surface including the support contact surface) of the insert mounting through-hole to the tool body has a predetermined surface roughness, and the surface is covered with a hard coating layer. The surface-coated insert of the present invention that is not present can prevent the occurrence of cracks and breakage at the contact surface with the supporting means that contacts the insert, and also the surface roughness of the flank and chip breaker, and the rake face. Since the residual stress of the hard phase is appropriately adjusted, it exhibits excellent fracture resistance and finished surface accuracy in cutting operations with high loads, and exhibits excellent cutting performance over a long period of use. It was confirmed that the tool life can be extended.

An insert substrate (sintered body) made of TiCN-based cermet was produced using raw material powder having the same composition as the raw material used in Example 1. Further, the insert substrate was wet-blasted under the conditions shown in Table 5 (except for the inner surface of the through hole). Further, before or after the wet blasting process, the cutting edge of the insert base was subjected to honing (brush honing) under the conditions shown in Table 5.
Thereafter, a PVD hard coating layer was formed with an average film thickness of 1.5 μm by an arc ion plating method using various materials shown in Table 5 on the surface excluding the inner surface of the through hole in the insert substrate. 20 surface-coated inserts were obtained. Reference Example 3 is an example in which a PVD hard coating layer was formed without applying wet blasting to the insert substrate.
For the insert substrate at the stage before forming the hard coating layer, the residual stress of the flank, the flank, and the surface roughness of the honing part were measured in the same manner as described above, and the flank of the insert after the hard coating layer was formed, Since the surface roughness of the honing part and the inner surface of the through hole was measured in the same manner as described above, the results are shown in Table 5.
Next, a cutting test was performed under the following conditions to evaluate the insert performance.
<< Cutting Test 5 >>
Work material: JIS-SNCM439 grooved round bar (6 grooves in the longitudinal direction),
Cutting speed: 140 m / min,
Feed rate: 0.3 mm / rev,
Cutting depth: 2mm
Wet intermittent cutting was performed, and the actual cutting time until replacement of the cutting edge was evaluated.
The time until replacement of the cutting edge is the time until it becomes impossible to continue actual cutting, such as chipping or chipping of the used cutting edge, or breakage of the insert, and normal cutting is maintained. If it is, the time until the flank wear width reaches 0.2 mm is taken.
<< Cutting Test 6 >>
Work material: JIS-S45C round bar,
Cutting speed: 240 m / min,
Feed rate: 0.12 mm / rev,
Cutting depth: 1.0mm
The flank wear width after 20 minutes of actual machining time was evaluated.
In addition, even if it was in the middle of processing, when the flank wear width reached 0.2 mm, the actual processing time until that time was evaluated as the life.
Table 6 shows the actual cutting time until the cutting edge replacement in the cutting test 5 and the reason for the cutting edge replacement, the flank wear width in the cutting test 6 and the appearance state of the finished surface of the work material at the end of cutting.

  From the results shown in Table 6, in any of the hard coating layers of various different materials as shown in Table 5, in the example of the present invention, excellent chipping resistance and finish in cutting with high load applied. It was confirmed that the surface accuracy was excellent, the cutting performance was excellent over a long period of use, and the tool life could be extended. In Reference Example 3 where the insert base was not wet-blasted, it was confirmed that the chipping resistance was poor and the appearance quality of the finished surface was poor.

    According to the present invention, a surface-coated TiCN that is capable of forming a machined surface with excellent chipping resistance and excellent finish surface accuracy under cutting conditions in which a high load acts on the cutting edge. In addition to providing a cutting insert made of basic cermet, even when this insert is applied to cutting under normal conditions, it exhibits excellent cutting performance over a long period of use. It can cope with energy saving and cost reduction sufficiently satisfactorily.

DESCRIPTION OF SYMBOLS 1 Surface covering titanium carbonitride based cermet cutting insert 2 Relief face 3 Honing part 4 Rake face 5 Chip breaker part 6 Mounting seating surface to tool body 7 Land part 8 Mounting through hole 8A Support tool contact surface 9 Tool body 9A Tool Support tool 9B as attachment means to the main body Support tool 10 as attachment means to the tool body Insert base 12 Rotating shaft 14 Blast gun G Polishing liquid

Claims (19)

Titanium carbonitride-based cermet having a through-hole for attachment to a tool body, a flank, a honing portion, and a rake face, and having a chip breaker formed by transferring the mold shape to the rake face during press molding A surface-coated titanium carbonitride-based cermet cutting insert formed by coating an insert base composed of a sintered body with a hard coating layer by physical vapor deposition;
Of the inner surface of the mounting through-hole, at least a support tool contact surface that comes into contact with a support tool as means for attaching to the tool body is configured by a surface that is not covered by the hard coating layer, and the support tool contact surface is The surface roughness of the surface of the insert base is more than 0.2 μm as the arithmetic average roughness Ra at a cutoff value of 0.08 mm. A surface-coated carbon having an arithmetic average roughness Ra of 0.08 mm or less and 0.2 μm or less, and the residual stress of the hard phase of at least the rake face of the insert substrate is 450 MPa or more in compression. Titanium nitride based cermet cutting insert.   At least the support contact surface of the through hole is formed of sintered skin, and the surface roughness is 0.3 μm or more in arithmetic average roughness Ra at a cutoff value of 0.08 mm. The surface-coated titanium carbonitride-based cermet cutting insert according to claim 1.   The surface coating according to any one of claims 1 and 2, wherein the residual stress of the hard phase at least on the surface portion of the rake face in the insert substrate is 600 MPa or more by compression. Titanium carbonitride-based cermet cutting insert.   The surface roughness of the honing part at the tip of the cutting edge in the insert base is formed smaller than the flank of the insert base and the surface roughness of the chip breaker. The surface-coated titanium carbonitride-based cermet cutting insert according to claim 1.   The surface roughness of the honing part in the insert substrate is not more than 0.1 μm in arithmetic mean roughness Ra at a cutoff value of 0.08 mm. 5. The surface-coated titanium carbonitride-based cermet cutting insert according to claim.   The hard coating layer includes at least one element selected from IVa group element, Va group element, VIa group element, Al, Si, Y, Mn, Ni, and S in the periodic table, and carbon, nitrogen, oxygen The compound according to any one of claims 1 to 5, wherein the compound comprises one layer or two or more layers of a compound comprising at least one element selected from boron. The surface-coated titanium carbonitride-based cermet cutting insert as described.   The surface-coated titanium carbonitride-based cermet cutting insert according to claim 6, wherein at least one of the hard coating layers is formed of a TiAlN layer.   The hard coating layer is composed of one layer or two or more layers selected from Ti carbide, nitride and carbonitride, and the total thickness of the hard coating layer is 0.5 to 15 μm. The surface-coated titanium carbonitride-based cermet cutting insert according to claim 6, wherein the cutting insert is made of cermet.   As the hard coating layer, from the side of the insert substrate, a TiN layer having a thickness of 0.1 to 1.0 μm, a TiCN layer having a thickness of 0.5 to 5.0 μm, and a TiN layer having a thickness of 0.1 to 1.0 μm. The surface-coated titanium carbonitride-based cermet cutting insert according to claim 8, wherein the layers are coated in that order. Titanium carbonitride-based cermet having a through-hole for attachment to a tool body, a flank, a honing portion, and a rake face, and having a chip breaker formed by transferring the mold shape to the rake face during press molding In a method for producing a surface-coated titanium carbonitride-based cermet cutting insert formed by coating an insert base composed of a sintered body with a hard coating layer by physical vapor deposition;
By the sintering method, the surface roughness of the support contact surface contacting at least the support as the means for attaching to the tool body in the mounting through hole is 0.2 μm in terms of arithmetic average roughness Ra at a cutoff value of 0.08 mm. An insert substrate manufacturing process for manufacturing an insert substrate having a roughness exceeding
By performing wet blasting in at least the region of the surface of the insert base body excluding the contact surface of the support, the surface roughness of the flank and the chip breaker is set to an arithmetic average roughness Ra at a cutoff value of 0.08 mm. And a wet blasting process in which the residual stress of the hard phase of the surface portion of the rake face is at least 450 MPa by compression,
After the wet blasting step, a coating step of forming a hard coating layer by a physical vapor deposition method in a region excluding at least the support contact surface of the surface of the insert substrate,
A method for manufacturing a surface-coated titanium carbonitride-based cermet cutting insert.   In the wet blasting process, a polishing liquid is sprayed from at least one blast gun while rotating around the axis while holding the insert base between a pair of rotating shafts rotatable around the axis. 11. The method for producing a surface-coated titanium carbonitride-based cermet cutting insert according to claim 10, wherein at least the surface of the insert base excluding the support contact surface is subjected to wet blasting.   In the wet blasting step, a wet blasting process is performed by injecting a polishing liquid from a blast gun at an injection angle of not less than 30 degrees and not more than 60 degrees with respect to the axial direction of the rotating shaft sandwiching the insert base body rotatably. The method for producing a surface-coated titanium carbonitride-based cermet cutting insert according to claim 11.   The method for producing a surface-coated titanium carbonitride-based cermet cutting insert according to claim 12, wherein, in the wet blasting step, the spray angle is set to 40 degrees or more and 50 degrees or less.   The honing process is performed on the cutting edge portion of the insert base body at the stage before the covering step after the wet blasting step, according to any one of claims 10 to 13. The manufacturing method of the surface covering titanium carbonitride based cermet cutting insert of description.   The honing process is performed by wet brush honing so that the surface roughness of the cutting edge portion of the insert base is 0.1 μm or less in terms of arithmetic average roughness Ra at a cutoff value of 0.08 mm. Item 15. A method for producing a surface-coated titanium carbonitride-based cermet cutting insert according to Item 14.   In the coating step, as the hard coating layer, at least one element selected from IVa group element, Va group element, VIa group element, Al, Si, Y, Mn, Ni, and S in the periodic table, and carbon A layer comprising one or two or more compounds composed of at least one element selected from nitrogen, oxygen, and boron is formed by physical vapor deposition. 15. A method for producing a surface-coated titanium carbonitride-based cermet cutting insert according to claim 15.   The method for manufacturing a surface-coated titanium carbonitride-based cermet cutting insert according to claim 16, wherein, in the coating step, at least one of the hard coating layers is formed of a TiAlN layer.     In the coating step, the hard coating layer is composed of one layer or two or more layers selected from Ti carbide, nitride, and carbonitride, and has a total film thickness of 0.5 to 15 μm. The method for producing a surface-coated titanium carbonitride-based cermet cutting insert according to claim 16, wherein:   In the coating step, as the hard coating layer, from the insert substrate side, a TiN layer having a thickness of 0.1 to 1.0 μm, a TiCN layer having a thickness of 0.5 to 5.0 μm, and a thickness of 0.1 to 0.1 μm. The method for producing a surface-coated titanium carbonitride-based cermet cutting insert according to claim 18, wherein a 1.0 μm TiN layer is formed in that order.

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