JP2012245581A - Cutting insert made from surface coated titanium carbon nitride-based cermet, and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting insert made from surface coated TiCN-based cermet excellent in chipping resistance and surface finish accuracy, under high load and cutting process conditions, and to provide a method for manufacturing the same.SOLUTION: In the cutting insert made from surface coated TiCN-based cermet excellent in chipping resistance and surface finish accuracy, an insert base, which has a through hole for attaching the insert to a tool body, a flank face, a honing part, a rake face, and a chip breaker prepared on the rake face, is coated with a hard coating layer by a PVD method. A support tool contact face of the through hole is not covered with a hard coating layer. A soft metal ooze layer whose main components are Co and Ni, and constituted of substantially single phase, is exposed from the topmost surface part thereof. Meanwhile, there is no metal ooze layer on the flank face and a chip breaker surface of the insert base. A surface roughness thereof is an arithmetic average roughness Ra of 0.2 μm or less when a cut off value is 0.08 mm.

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.

  By the way, TiCN-based cermet cutting inserts are generally manufactured by a sintering method. However, when a TiCN-based cermet cutting insert is manufactured by a sintering method, a metal such as Ni or Co is formed on the surface of the sintered body. A layer (metal-enriched layer) enriched with a metal mainly composed of a binder phase may be formed. This type of metal-enriched layer is generally referred to as a metal stagnation layer because it is formed by the metal bonding layer component leaching from the inside to the surface during the sintering process. If this kind of metal stagnation layer is formed on the surface, the structure state of the sintered body surface becomes non-uniform, so that the fracture resistance as a cutting insert is reduced, or welding with the work material is caused. It is known that there is a problem of generating defects during cutting (Patent Documents 3 to 5).

  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 layer or two or more layers of a compound composed of at least one element and at least one element selected from carbon, nitrogen, oxygen, and boron is obtained by physical vapor deposition (PVD method). Also known are surface-coated TiCN-based cermet cutting inserts which are coated. 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 6, 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 that a residual stress of the same level as that of the stress be applied to the vicinity of the surface of the cutting insert. In such a surface-coated TiCN-based cermet cutting insert of Patent Document 6, 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 Publication No. 60-34618 Japanese Patent Laid-Open No. 4-146006 Japanese Patent No. 3803694 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.
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 the breakage from the inner surface of the through hole occurs, it is impossible to replace the same insert with another cutting edge, which is a fatal problem as a detachable insert. Such a problem has also occurred in a surface-coated TiCN-based cermet cutting insert in which a TiCN-based cermet is used as an insert base and a hard coating layer is formed on the surface by a PVD method.
However, in any of the proposals of Patent Documents 1 to 6, the occurrence of cracks and breakage from the inner surface of the insert through hole that comes into contact with the support under high load cutting conditions is not particularly considered, Therefore, the actual situation is that the occurrence of the above-mentioned problems could not be avoided.
Therefore, in the present invention, 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 part, not only the cutting edge part is suppressed, but also the inner surface of the through hole It is an object of the present invention to provide a surface-coated TiCN-based cermet cutting insert that can suppress the occurrence and progress of cracks and breakage from the surface, thereby exhibiting 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 PVD method. In a surface-coated TiCN-based cermet cutting insert (hereinafter referred to as a surface-coated TiCN insert) formed by forming a through-hole inner surface (support tool contact surface) in contact with a support tool such as a screw, L-shaped lever, or eccentric pin As a result of studying the relationship between the surface holding TiCN insert and the force to hold the insert on the tool body, when the insert base material powder is molded and then sintered, the insert base is manufactured. On the entire skin, there is a metal wrinkle layer enriched with one or two of Co and Ni, which is a metal binder phase component of cermet that is harmful to tool performance. In particular, a soft metal squeeze layer composed of a substantially single phase mainly composed of one or two of Co and Ni is formed on the outermost surface portion of the support contact surface in the through hole. Actively formed with a predetermined layer thickness and a predetermined surface occupancy (area ratio), and the support contact surface is not covered with a hard coating layer by the PVD method, but exposed as a metal skin layer on the sintered skin. In this case, cracks and breakage from the contact surface of the support tool in the through hole can be suppressed and progressed even under cutting conditions where high loads are applied. They found that cutting performance was demonstrated and the tool life could be extended.

  That is, under cutting conditions in which an extremely high load is applied to the insert, such as intermittent cutting or milling, a high load is also generated on the inner surface of the insert through hole (support tool contact surface) that contacts the support tool. Although there is a risk of cracks and breakage, the support contact surface is kept exposed to the soft and tough metal squeeze layer to prevent cracks and breakage from the support contact surface. As a result, it has been found that the tool life can be extended, and the present invention has been made.

  Note that the above-described metal stagnation layer is not a layer composed of two or more phases containing hard particles constituting the hard phase of the TiCN-based cermet, but one or two of Co and Ni constituting the bonded phase of the TiCN-based cermet. It is important that the layer is a soft and tough metal squeeze layer composed of a substantially single phase mainly composed of seeds.

  However, when a metal squeeze layer is formed on the outermost surface part of the inner surface of the through hole by sintering, a metal squeeze layer is similarly formed on the flank of the cutting edge part involved in cutting and the surface of the chip breaker. Usually, it is formed, but if a metal cover layer is formed on the surface of the flank and chip breaker and a hard coating layer is formed on the surface by the PVD method, the adhesion strength of the hard layer is low. Thus, the hard coating layer is easily peeled off under high-load cutting conditions, and as a result, the finished surface accuracy and fracture resistance of the work material are deteriorated. However, if the surface of the insert substrate on which the metal wrinkle layer is formed (but the portion of the inner surface of the through hole excluding the support contact surface) is subjected to wet blasting before the formation of the hard coating layer by the PVD method. In particular, it is possible to remove the metal stagnation layer formed on the flank and chip breaker surface, and at the same time, it is possible to smooth the surface, thereby improving the finished surface accuracy and chipping resistance. I found out to get.

In addition, if a metal stagnation layer is generated on the surface of the cutting edge part, the metal binder phase component may be poor in the region below the metal stagnation layer and the toughness may be reduced. It has been found that the chipping resistance can be further improved by smoothing the surface of the insert substrate and simultaneously applying a compressive residual stress to at least the rake face of the insert substrate.
However, if the effect of wet blasting is too strong, the surface roughness of the surface to be treated will be adversely affected, and the finished surface accuracy and chipping resistance will be adversely affected. Therefore, the surface roughness should be controlled so that it does not exceed a certain range. It is important to.

  As described above, among the surfaces of the insert base made of the sintered body of the titanium carbonitride-based cermet, the inner surface of the mounting through-hole, particularly the surface in contact with the mounting means (support) for the tool body (support tool contact surface), The metal stagnation layer remains exposed on the sintered skin as described above, and the metal scouring layer is removed by applying wet blasting to the rest of the insert substrate, especially the flank and chip breaker surface. At the same time, the surface roughness and residual stress of the part are appropriately adjusted, and when the hard coating layer is formed on the surface of the insert substrate by the PVD method, the hard coating layer is not formed on the support contact surface. (I.e., so that the metal wrinkle layer remains exposed). Loss of greatly improved, especially also in the cutting of high load, support the contact surfaces of the cracking and breakage of the through hole, found that it is possible to suppress the progress is of the present invention has been accomplished.

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. An insert substrate composed of a sintered body made of titanium carbonitride-based cermet having a chip breaker formed by transferring the mold shape during press molding is coated on the surface with a hard coating layer by physical vapor deposition. In the surface-coated titanium carbonitride-based cermet cutting insert,
Of the inner surface of the through hole for mounting, at least a support tool contact surface that comes into contact with a support tool as means for attaching to the tool body is composed of sintered skin not covered with the hard coating layer, and the support tool contact. In the outermost surface portion of the surface, a metal single layer composed of a substantially single phase mainly composed of one or two of Co and Ni has a layer thickness of 0.1 μm or more and 5 μm or less and a surface occupation of 60 area% or more. On the other hand, the flank face of the insert base and the surface of the chip breaker do not have the metal squeeze layer, and the flank face of the insert base and the surface roughness of the chip breaker have a cutoff value. The arithmetic average roughness Ra at 0.08 mm is 0.2 μm or less.

  Moreover, the surface-coated titanium carbonitride-based cermet cutting insert according to the second aspect of the present invention is the metal-striping on the support contact surface of the through hole in the surface-coated titanium carbonitride-based cermet cutting insert of the first aspect. The surface occupancy of the layer is 80 area% or more.

  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 450 MPa or more in compression.

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

  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 at the tip of the cutting edge in the insert base is formed to be smaller than the flank of the insert base and the surface roughness of the chip breaker.

  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 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.

  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 any one of the first to sixth modes, 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.

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

  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 seventh 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 tenth aspect of the present invention is the surface-coated titanium carbonitride-based cermet cutting insert according to the ninth aspect 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 11th-20th form of this invention is related with the manufacturing method of the surface covering titanium carbonitride based cermet cutting insert.
That is, first, a method for producing a surface-coated titanium carbonitride-based cermet cutting insert according to an eleventh aspect 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 face is provided on the rake face. An insert substrate made of a titanium carbonitride-based cermet having a chip breaker formed by transferring the mold shape during press molding is coated with a hard coating layer by a physical vapor deposition method. In the method of manufacturing the surface-coated titanium carbonitride-based cermet cutting insert;
An insert substrate manufacturing process for manufacturing an insert substrate by a sintering method so that a metal stagnation layer composed of a substantially single phase mainly composed of one or two of Co and Ni is formed on the surface;
By subjecting the surface of the insert base to wet blasting within a region excluding the support contact surface that contacts the support as a means for attaching to the tool body in the mounting through hole, the surface portion of the support contact surface The surface of the flank and chip breaker is removed from the flank and chip breaker surface while leaving the metal stubble layer on the surface, and the surface roughness of the flank and chip breaker is calculated as the 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 the support contact surface of the surface of the insert base,
It is characterized by having.

  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, 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 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. 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 fourteenth aspect of the present invention is the method for producing a surface-coated titanium carbonitride-based cermet cutting insert according to the thirteenth 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 fifteenth aspect of the present invention is the surface-coated titanium carbonitride-based cermet cutting according to any one of the eleventh to fourteenth 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 manufacturing a surface-coated titanium carbonitride-based cermet cutting insert according to the sixteenth aspect of the present invention is the method for manufacturing a surface-coated titanium carbonitride-based cermet cutting insert according to the fifteenth aspect, wherein the honing process 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 seventeenth aspect of the present invention is the surface-coated titanium carbonitride-based cermet cutting according to any one of the eleventh to sixteenth 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.

  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 seventeenth aspect. Among the hard coating layers, at least one layer is formed of a TiAlN layer.

  And the manufacturing method of the surface-coated titanium carbonitride-based cermet cutting insert according to the nineteenth aspect of the present invention is the manufacturing method of the surface-coated titanium carbonitride-based cermet cutting insert according to the seventeenth aspect, in the coating step. 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 method for producing a surface-coated titanium carbonitride-based cermet cutting insert according to the twentieth aspect of the present invention is the method for producing a surface-coated titanium carbonitride-based cermet cutting insert according to the nineteenth aspect. 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 The support tool contact surface in contact with the support tool as the attachment means is constituted by a sintered skin not covered with the hard coating layer, and a predetermined surface occupancy (area ratio) is provided on the support tool contact surface of the sintered skin. ), A soft and tough metal squeeze layer composed of a substantially single phase mainly composed of one or two of Co and Ni having a predetermined layer thickness is formed. Since you are the states, even at the time of cutting of a high load, it is possible to suppress the occurrence and development of a crack and breakage of the support member contacting surface of the through hole.
Further, here, since the hard coating layer by the PVD method is generally harder than the cermet of the base, if the hard coating layer is formed by the PVD method on the surface of the metal stagnation layer of the support contact surface of the through hole, At the time of high-load cutting, cracks and breakage from the support contact surface are likely to occur. In this case, if a crack or breakage occurs in the hard coating layer on the contact surface of the support, the defect progresses to the insert base from that point, and it is assumed that a predetermined amount of the metal stagnation layer exists on the inner surface of the through hole. However, in the present invention, as described above, the support contact surface is not covered with the hard coating layer, and remains a soft and tough metal stagnation layer. Can also be prevented. On the other hand, the flank and chip breaker of the insert are subjected to wet blasting so that the metal stagnation layer does not exist on the flank and chip breaker surface, and the surface roughness of the flank and chip breaker is reduced. The arithmetic average roughness Ra at a cutoff value of 0.08 mm is 0.2 μm or less, and at the same time the surface is smoothed, and at the same time, compressive residual stress is applied to the hard phase of the surface portion of the rake face. As a result, it is possible to ensure excellent fracture resistance and maintain excellent finished surface accuracy over a long period of use.

  Further, according to the method of manufacturing the surface-coated TiCN-based cermet cutting insert of the present invention, the metal base layer as described above is formed on the surface of the insert base when the insert base is manufactured by the sintering method, and the insert base is formed on the insert base. On the other hand, by performing wet blasting in the region excluding the support contact surface, the metal close-up layer is formed from the flank and the surface of the chip breaker with the metal close-up layer remaining on the surface of the support contact surface. In addition, the surface roughness of the flank and chip breaker and the residual stress of the hard phase at least on the surface of the rake face are adjusted within predetermined ranges, respectively, and the support contact surface of the surface of the insert base is further removed. By forming a hard coating layer in the removed area by physical vapor deposition, cutting with high load as described above In this case, a surface-coated TiCN-based cermet cutting insert that can suppress the occurrence and progress of cracks / breakage from the support contact surface of the through hole, has excellent fracture resistance, and has excellent finished surface accuracy, It 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 layer or two or more layers of a compound composed of these elements is formed by physical vapor deposition (PVD method). And the support tool contact surface of the said through-hole is mainly comprised by the sintered skin, and 1 type or 2 types of Co and Ni which are the metal binder phase components of a cermet are formed in the outermost surface part of the support tool contact surface. An enriched metal stripe layer is formed, and the support contact surface on the inner surface of the through hole is not covered with the hard coating layer, and the metal stripe layer on the sintered skin is exposed.
Here, in the present invention, the soft and tough metal squeeze layer formed on the support contact surface of the inner surface of the through hole is connected to the support such as a screw, an L-shaped lever, and an eccentric pin for fixing the insert to the tool body. The tool life is extended by using it as an anti-cracking layer that tends to occur on the contact surface.
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.

  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 insert of the present invention, a soft metal squeeze layer composed of a substantially single phase mainly composed of one or two of Ni and Co formed on the outermost surface portion of the support contact surface of the through-hole, The surface occupancy (area ratio) is 60% or more, preferably 80% or more, and the thickness is in the range of 0.1 to 5 μm. Here, when the surface occupancy (area ratio) of the metal stagnation layer on the support contact surface of the through hole is less than 60%, the effect of preventing the occurrence of cracks and breakage on the support contact surface is small, and cracks and damage The effect of restraining the progress of is also reduced. If the thickness of the metal contact layer on the support contact surface of the through hole is less than 0.1 μm, if the support contact surface is cracked or damaged, the effect of suppressing the progress is small. If the thickness of the shimidashi layer exceeds 5 μm, the metal binder phase component in the cermet is too poor in the lower part of the metal shimidashi layer generated at the cutting edge, and then wet blasting is performed. It becomes difficult to remove the metal stripe layer formed on the flank and chip breaker surface.

  The surface roughness of the support contact surface of the through hole in which the metal squeeze layer is formed is not particularly limited, but this support contact surface is a sintered skin and is usually arithmetic at a cutoff value of 0.08 mm. The average roughness Ra is a rough surface exceeding 0.2 μm and not more than about 0.5 μm. And since the roughness of the support tool contact surface is relatively large as described above, the friction with the support tool is increased to prevent the occurrence of slipping between the support tool and the support tool contact surface. This contributes to preventing the occurrence of minute vibrations and abnormal vibrations, and suppressing the occurrence and progress of cracks and breakages from the contact surface of the support.

  In addition, the surface occupancy ratio (area ratio) and layer thickness of the soft metal component in the metal wrinkle layer mainly affect the blending ratio of the raw material powder for sintering and the sintering conditions, especially the cooling conditions after heating for sintering. Therefore, in the sintering step, the blending ratio and the sintering conditions are adjusted so that a sintered skin having a metal wrinkle layer that satisfies the above conditions is obtained.

  Here, in order to construct the support contact surface of the through hole with the metal skin layer of the sintered skin, when manufacturing the insert base by adjusting the manufacturing conditions of the insert base (sintering conditions) and the sintering raw material blending conditions, Usually, a metal wrinkle layer is naturally formed on the flank of the insert base and the surface of the chip breaker. If the hard coating layer is formed on the surface of the flank and the chip breaker in this way by the PVD method, the adhesion strength of the hard coating layer is lowered as described above. The hard coating layer easily peels off under high-load cutting conditions, and as a result, the finished surface accuracy and fracture resistance of the work material are deteriorated. Therefore, in the present invention, the surface of the insert base (excluding the support contact surface of the through hole) is subjected to wet blasting, thereby removing the metal stagnation layer formed on the flank and the chip breaker surface. The surface and the chip breaker are smoothed at the same time, and at the same time, residual stress is applied to at least the rake face of the insert substrate, thereby improving the finished surface accuracy and chipping resistance.

  As described above, the wet blast treatment contributes not only to the removal of the flank of the insert base and the chip breaker surface metal stripe layer, but also to the smoothing of the flank and the chip breaker of the insert base. The smoothing of the flank of the insert substrate mainly contributes to the improvement of the finished surface accuracy of the work material, and the reduction of the surface roughness of the chip breaker mainly contributes to the improvement of fracture resistance. If the flank face and the surface roughness of the chip breaker become a rough surface with an arithmetic mean 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.

The flank and chip breaker surface roughness defined here are values for the surface of the insert substrate (the surface from which the metal squeeze layer has been removed) 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, in the hard coating layer by the arc ion plating method, granular projections called droplets may occur on the surface of the coating layer, but the arithmetic average roughness Ra of the insert surface in this application is that there are droplets. It is the surface roughness measured in the part which is not.

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, after performing wet blasting on the insert base, the honing process using a wet brush or the like is applied to the tip of the insert base so that the surface roughness of the honing part formed at the tip of the tip is higher than other parts. It is desirable to make it smaller. 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, it is possible to improve the accuracy of the finished surface at the initial stage of cutting and sufficiently improve the fracture resistance 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.

  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.

  Further, by performing wet blasting on the insert base as described above, a compressive residual stress is applied to the hard phase at least on the surface of the rake face simultaneously with removal of the flank and chip breaker surface on the insert base. In this way, by applying compressive residual stress to the rake face, it is possible to further improve the chipping resistance of the cutting edge portion against a high load acting during cutting. Here, when the compressive residual stress of the hard phase on the surface portion of the rake face is less than 450 MPa, the effect of improving the fracture resistance against high loads is small. The value of the compressive residual stress applied to is set to 450 MPa or more, preferably 600 MPa or more.

The value of the residual stress applied to the hard phase of the surface portion of the insert substrate in the present invention is “X-ray evaluation of residual stress” issued by Yokendo Co., Ltd. (Keisuke Tanaka, Kenji Suzuki, Yoshiaki Akiba) ) Measured by an X-ray diffractometer using the well-known sin ² Ψ method described at the beginning of Chapter 6 (P99 to 105).
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 residual stress measurement, the diffraction peak of 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, 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 harder than the cermet of the substrate, and thus can improve wear resistance. If the surface of the insert substrate smoothed to Ra 0.2 μm or less by PVD as described above is subjected to PVD, the surface of the hard coating layer by PVD becomes a smooth surface of about Ra 0.25 μm or less. Excellent chipping resistance and finished surface accuracy can be secured. However, as already described, if the support tool contact surface of the through hole (the surface exposed by the metal stripe layer) is covered with a hard coating layer by the PVD method, the support tool contact surface becomes hard, At the time of cutting with a high load, cracks and breakage from the contact surface of the support are likely to occur. In this case, if a crack or breakage occurs in the hard coating layer on the contact surface of the support, the defect progresses to the insert base from that point, and it is assumed that a predetermined amount of the metal stagnation layer exists on the inner surface of the through hole. However, cutting may be impossible. Therefore, in the present invention, the support tool contact surface is not covered with a hard coating layer made of PVD, and remains a soft metal squeeze layer.

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.
When a finished surface of the work material is required, the hard coating layer is composed of one layer or two or more layers selected from Ti carbide, nitride, and carbonitride having excellent welding resistance. In this case, since the affinity between the material that forms the hard coating layer and the work material (iron-based) is low, the welding phenomenon is unlikely to occur during cutting and a good work material finish It is particularly suitable for a surface-coated titanium carbonitride-based cermet insert that can obtain surface accuracy and often requires a machined surface roughness. In that case, 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 preferably selected to be 0.5 to 15 μm. When the total film thickness of the hard coating layer is less than 0.5 μm, the wear resistance is not sufficient. On the other hand, when the total film thickness exceeds 15 μm, it has been confirmed that the hard coating layer tends to be peeled off. It is important to adjust the thickness appropriately.
More specifically, in the case of forming a hard coating layer by a PVD method in a plurality of layers, a TiN layer having a film thickness of 0.1 to 1.0 μm, a film thickness of 0.5 to 5.0 μm from the insert substrate side. The TiCN layer and the TiN layer having a film thickness of 0.1 to 1.0 μm are desirably coated in that order.
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 described, the surface of the sintered body is a substantially single phase mainly composed of one or two kinds of Co and Ni, which are metal bonding layer components of the titanium carbonitride-based cermet. The mixing ratio of the raw material powder, the sintering temperature, the sintering atmosphere, the cooling conditions, etc. are formed so that the metal wrinkle layer made of Adjust appropriately. 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. In addition, the seating surface for attaching the insert to the tool body may have a grinding surface by a grindstone, but the flank surface is not usually ground and is formed by a die during press molding. Is.

Wet blasting:
For the insert base, which is a sintered body obtained as described above, the metal base layer is removed and the surface smoothed on the insert base surface excluding the support contact surface on the inner surface of the mounting through hole. Further, wet blasting is performed for the purpose of imparting compressive residual stress.
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 excessively large, which may cause coarse cracks on the surface and inner surface of the insert base, and because the polishing ability is low, the metal stagnation layer may not be sufficiently removed. Drive blast, which blasts the insert surface with (powder flow / air flow), has less processing energy than wet blasting, so it cannot sufficiently remove the metal stripe layer, and also has smooth surface and compressive stress. Insufficient operation, and more likely to cause bite / residue of sprayed abrasive on the treated surface There is a problem.

Therefore, in the present invention, without causing the above-described adverse effects, the metal stagnation layer on the surface of the insert substrate excluding the support contact surface on the inner surface of the mounting through hole is surely removed, and further for smoothing the surface and applying compressive residual stress. As a means for this, wet blasting is adopted.
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. The surface portion of the insert substrate excluding at least the support contact surface on the inner surface of the mounting through-hole without damaging the shape of the insert breaker or the chip breaker portion having a three-dimensional shape molded by a mold. In addition, it was possible to reliably remove the metal stagnation layer, and at the same time, it was possible to smooth the surface and 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 portion, the grinding force is large, the metal stripe layer can be effectively removed, 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 in order to remove the metal stripe layer reliably and finish the insert surface to a predetermined surface roughness. Not only does the wet blasting process take a long time, the productivity deteriorates, but also defects such as cracks due to excessive wet blasting 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), a pair of rotating shafts capable of rotating an insert substrate 10 with a sintered skin made of a titanium carbonitride-based cermet having a metal wrinkle layer formed on the entire surface of the substrate around an axis (O). For example, the two blast guns 14 facing each other with an injection angle θ of 45 degrees with respect to the axial direction of the rotation axis (O) while rotating around the axis while being sandwiched and held by 12 By spraying the polishing liquid G onto the surface of the insert base 10 and performing wet blasting one by one, it is possible to uniformly treat the entire surface of the insert base 10 except at least the support contact surface on the inner surface of the mounting through hole. it can.

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 the 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, particularly the support contact surface, is not wet blasted and the surface state immediately after sintering is maintained. Is done. That is, the support contact surface of the through-hole is a soft metal squeeze layer composed of a substantially single phase mainly composed of one or two kinds of Co and Ni having a predetermined surface occupation ratio (area ratio) and a predetermined layer thickness. The sintered skin on which is formed is maintained.
On the other hand, from the flank of the insert base 10 and the surface of the chip breaker, the metal squeeze layer is removed by wet blasting, and at the same time a smooth surface is formed. 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 on which the metal stripe layer exists. 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.
In this way, by using the wet blasting apparatus having the structure as described above, the individual injection conditions are appropriately set for the insert base having various shapes and chip breakers, and the optimum wet blasting process is performed. Can be applied.

  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 metal squeeze layer with the sintered skin on the surface that contacts at least the support that is the attachment means to the tool body among the inner surfaces of the attachment through holes 8. It suffices to perform wet blasting on the surface of the portion that is determined by design not to contact the support.

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 a honing process (preferably brush honing, more preferably wet brush honing) of the cutting edge as a step after the wet blasting process 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 as described above, it is possible to improve the accuracy of the finished surface at the initial stage of cutting and sufficiently improve the fracture resistance 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 composed of one layer or two or more layers of a compound composed of 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 support contact surface of the through-hole needs to be a sintered skin with the metal wrinkle layer exposed even in the final product. Therefore, when applying the PVD method 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 pressing P30 grade TiCN-based cermet raw material powder having the following raw material composition, sintering is performed under the following conditions, and various thicknesses and surfaces are adjusted by adjusting the sintering temperature, nitrogen atmosphere pressure, and cooling conditions. Occupancy rate (area ratio) has a soft and tough metal squeeze layer composed of a substantially single phase mainly composed of one or two of Co and Ni, and has the shape and dimensions specified in ISO / DNMG150612. Sintered bodies (insert bases) A to E made of TiCN-based cermet were prepared.
Table 1 shows the characteristics of the insert bases A to E made of each TiCN-based cermet. In addition, on the surfaces of the insert bases A to D made of TiCN-based cermet, a substantially single-phase metal stagnation layer mainly composed of Co and Ni was generated with the layer thickness and surface occupancy shown in Table 1. .
Raw material composition:
All of TiCN powder, WC powder, TaC powder, NbC powder, Co powder, and Ni powder having an average particle diameter of 0.5 to 2 mm are 45 wt%, 22 wt%, 3 wt%, 10 wt%, 15 wt%, 5 wt%, respectively. %, 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 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 133 Pa, the temperature is increased from 1350 ° C. to a predetermined sintering temperature (1500 ° C.) at a rate of 1.5 ° C./minute, and then maintained at the sintering temperature for 60 minutes in the same atmosphere.
(4) In a vacuum atmosphere of 10 Pa or less from the sintering temperature to 1200 ° C., cooling at various cooling rates within a range of 0.5 to 10.0 ° C./min,
(5) Furnace cooling from 1200 ° C. was performed in an Ar atmosphere of 90 kPa or less.
In addition, a nylon brush containing abrasive grains is used for the cutting edge, and a waterfall-type curved surface having a width measured from the rake face side of 0.11 mm and a width measured from the flank face side of 0.06 mm Honing was performed by wet processing.

Using the above-mentioned TiCN-based cermet insert bases B, C, and D with alumina having a center particle diameter of 40 μm as an injection abrasive, using the wet blasting apparatus shown in FIG. The insert substrate of the present invention 1-5 was manufactured by performing wet blasting. 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 injection angle θ is constant 45 °, and the entire surface of the insert substrate is excluded except for the portion sandwiched and held between the pair of rotating shafts (excluding the inner surface of the through hole). On the other hand, wet blasting was not performed on the inner surface of the through hole of the insert base, and the sintered skin on which the metal stagnation layer was formed was 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, about the inner surface of the through hole including the support tool contact surface, the sintered skin on which the metal stagnation layer was formed was maintained.

In the above process, the surface occupancy ratio of the metal base layer formed on the inner surface and clearance surface of the insert hole and the outermost surface of the chip breaker of the insert substrate of the present invention 1-5 before coating with the hard coating layer (Area ratio) and its layer thickness were measured using an electron microscope.
Similarly, the residual stress of the hard phase on the surface portion of the insert substrate of the present inventions 1 to 5 before coating with the hard coating layer was measured on the flat surface of the insert substrate flank by the aforementioned X-ray diffractometer.
Furthermore, according to JIS B0601-1994 (2001), the cut-off value of 0 according to JIS B0601-1994 (2001) is used for the flank, chip breaker, and surface roughness of the insert breaker of the present invention 1-5 of the present invention 1-5 before coating with a hard coating layer. It was measured by arithmetic average roughness Ra at 0.08 mm. In addition, the breaker bottom was measured regarding the surface roughness of the chip breaker.
Table 2 shows measured values of the surface occupancy ratio (area ratio), the layer thickness, the residual stress, and the surface roughness of the metal stripe layer.
In the insert bases of the present inventions 1 to 5, 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 treatment angle is basically set so that a similar effect is applied to the flank and rake face by setting the injection angle at the time of wet blasting to 45 °, the rake face, especially the flank Land area near the cutting edge located almost perpendicular to the surface and the bottom of the breaker (on the rake face, the residual stress value of the land near the cutting edge and the deepest breaker that curves in a concave shape is important for improving fracture resistance. ) Is considered to be substantially equivalent to the residual stress measured on the flank, so that the residual stress of the insert substrate is represented by the residual stress measured on the flank.
Further, regarding the surface roughness, since the spray angle at the time of wet blasting was 45 °, the surface roughness of the chip breaker (breaker bottom) was almost the same as the surface roughness of the flank.

    Furthermore, with respect to the insert at the stage after forming the hard coating layer on the surface of the insert substrate by the PVD method except the inner surface of the through hole, the surface roughness of the flank, chip breaker, honing part, and inner surface of the through hole is the same as described above. The measurement results are also shown in Table 2. In addition, regarding the surface roughness of the chip breaker, the breaker bottom was measured in the same manner as the insert substrate before the surface coating.

For comparison, by processing the insert substrate made of TiCN-based cermets A, B, C, and E under the conditions shown in Table 2, the surface occupancy (area ratio) and layer thickness of the metal stripe layer The insert bases of Comparative Examples 1 to 5 having the same composition, shape, and dimensions as those of the insert bases of the first to fifth aspects of the present invention are manufactured by changing the residual stress and the surface roughness of the hard phase. A hard coating layer of a single TiAlN layer having an average thickness of 1.5 μm was deposited on the surface of the substrate excluding the through-holes by applying the arc ion plating method as the PVD method in the same manner as described above. 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).
Further, with respect to the insert substrate (after wet blasting) manufactured in the same manner as in the present invention 3, the entire surface of the insert substrate, including the inner surface of the through hole including the support contact surface, is subjected to the PVD method in the same manner as described above. As an insert of Comparative Example 6, an arc ion plating method was applied and a hard coating layer of a single TiAlN layer having an average thickness of 1.5 μm was deposited. That is, the insert of Comparative Example 6 is an example in which a hard coating layer is also formed on the inner surface of the through hole.
Then, the surface occupancy ratio (area ratio) and the layer thickness of the metal stagnation layer are measured for each of the insert bases of Comparative Examples 1 to 6 in the stage before coating with the hard coating layer by the same measurement method as described above. The residual stress on the flat surface of the insert base flank of Comparative Examples 1 to 6 before coating with the hard coating layer was measured with an X-ray diffractometer, and the flank of the insert base before the hard coating layer was coated. The surface roughness of the chip breaker and the honing part was measured with the arithmetic average roughness Ra at a cutoff value of 0.08 mm in accordance with JIS B0601-1994 (2001). Regarding the surface roughness of the chip breaker, the bottom of the breaker was measured.
Table 2 shows the measurement results.

    Furthermore, the surface roughness of the flank, chip breaker, honing part, and inner surface of the through hole was the same as described above for the inserts of Comparative Examples 1 to 6 at the stage after the hard coating layer was formed on the surface of the insert substrate by the PVD method. The measurement results are also shown in Table 2.

According to Table 2, increasing the wet blast injection pressure on the insert base surface (flank and chip breaker) has the effect of increasing the compressive residual stress, but conversely when the injection pressure is higher than the predetermined range. 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 0.05 μm or 0.06 μm. However, if this surface is subjected to wet blasting, the surface roughness is also increased. It turns out that smoothness falls.
In the present invention, the inner surface of the through hole has a metal stripe layer having a predetermined thickness, and the roughness of the insert surface is improved by wet blasting, and a high compressive residual stress is applied. Also, the surface roughness after wet blasting of the present invention 5 using TiCN-based cermet D, whose roughness of the insert surface after sintering is originally small, is not greatly improved.
In Comparative Example 1, since the wet blast treatment was performed on the TiCN-based cermet A having a thickness of 7 to 9 μm, the metal stripe layer was 0.5 MPa in order to completely remove the metal stripe layer on the flank and chip breaker surface. Required injection pressure. As a result, from the viewpoint of surface roughness, overtreatment was performed, so that the flank and the surface roughness of the honing portion became a rough surface exceeding 0.2 μm.
In Comparative Example 4, after being manufactured in the same process as in the present invention 4, only the inner surface of the through hole was subjected to wet blasting by another insert holding method in order to remove the metal squeeze layer on the inner surface of the through hole. It is.

Next, a cutting test was performed under the following conditions in a state where each of the cutting inserts was fixed to the tip of the cutting tool with the L-shaped lever shown in FIG.
<< Cut Test 1 >> Wet Intermittent High Feed and High Cut Cutting Work Material: JIS-S55C Grooved Round Bar (Grooves are 4 grooves in the longitudinal direction)
Cutting speed: 200 m / min.
Feed: 0.6 mm / rev.
Cutting depth: 5mm
The actual cutting time until cutting edge replacement in the cutting test 1 was evaluated.
Table 3 shows the reason for the cutting edge replacement and the state of the cutting surface during the cutting edge replacement, along with the actual cutting time until the cutting edge replacement.
The time until replacement of the cutting edge is until the cutting edge is used, such as chipping or chipping, or it is severely damaged from the inner surface of the through-hole that contacts the L-shaped lever. And when normal cutting was maintained, the time until the flank wear width reached 0.4 mm was used.

According to Table 3, since the present inventions 1 to 5 have a metal stripe layer having a predetermined thickness and a predetermined surface occupancy on the inner surface of the through-hole, the wet cutting is performed with high feed and high cutting with high load. Because there is no major damage from the inner surface of the through-hole that contacts the L-shaped lever, and the metal roughness layer is removed from the flank and chip breaker, the surface roughness is improved, and high compressive residual stress is applied. Also, the used cutting edge part showed a long service life. Furthermore, since the surface roughness of the cutting edge portion was improved, a good glossy finished surface was exhibited until just before the cutting edge portion was replaced.
On the other hand, in Comparative Example 1 in which a thick metal stagnation layer having a thickness of 7 to 9 μm was formed on the entire circumferential surface of the insert after sintering, the surface roughness of the insert was not sufficiently improved, and further directly below the metal stagnation layer. Although it is considered that the degree of deterioration of the metal binder phase is large, the defect was generated in a relatively short time even though a large compressive residual stress exceeding 700 MPa was applied by wet blasting. In addition, since the surface roughness of the insert has not been improved sufficiently, the finished surface shows a cloudy finished surface that is less glossy than at the start of cutting, and if the evaluation of the cutting surface is also included in the criteria for replacing the cutting edge In this situation, cutting must be finished immediately after the start of cutting.
In Comparative Examples 2 and 3 in which the flank and the chip breaker metal stripe layer were not removed, the metal stripe layer at the cutting edge did not provide sufficient adhesion strength of the hard coating layer, and the coating layer was peeled off during cutting. As a result, the processing finish surface became cloudy, and the surface roughness and compressive residual stress of the insert cutting edge portion were not sufficient, so that the used cutting edge portion became defective and the cutting was completed in a short time.
In Comparative Examples 4 and 5 having no metal squeeze layer inside the through-hole, they were severely damaged from the inner surface of the through-hole in contact with the L-shaped lever in the initial stage of cutting. For this reason, when there is continuous cutting, it is not possible to replace with another cutting edge portion, and it is necessary to replace the insert itself.
Further, in Comparative Example 6, the inner surface of the through hole was coated with a hard coating layer by the PVD method, but in this case, the hard coating layer was cracked / damaged on the support contact surface inside the mounting through hole, As a result of the defect progressing to the insert base starting from that point, the insert itself was severely damaged during cutting and cutting was stopped.

An insert composed of a TiCN-based cermet having a through-hole having a shape and dimensions specified in ISO / CCMT120408 after press-molding a raw material powder of a P20 grade TiCN-based cermet having the following raw material blending composition and sintered under the following conditions: Bases (sintered bodies) F to H were prepared. Table 4 shows the characteristics of the cermet substrates F to H made of this TiCN-based cermet.
On the surfaces of the TiCN-based cermets F and G, a substantially single-phase metal stagnation layer composed mainly of Co and Ni having the layer thickness and surface occupancy shown in Table 4 was formed.
Raw material composition:
All of TiCN powder, WC powder, TaC powder, NbC powder, Mo ₂ C powder, Co powder, and Ni powder having an average particle diameter of 0.5 to 2 mm are 50 wt%, 15 wt%, 3 wt%, and 6 wt%, respectively. They were blended so as to be 10 wt%, 8 wt%, and 8 wt%, 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 200 Pa, the temperature is increased from 1350 ° C. to a predetermined sintering temperature (1550 ° C.) at a rate of 1.5 ° C./minute, and then maintained at the sintering temperature for 60 minutes in the same atmosphere.
(4) In a vacuum atmosphere of 10 Pa or less from the sintering temperature to 1200 ° C., cooling at various different cooling rates within a range of 2.0 to 10.0 ° C./min,
(5) Furnace cooling from 1200 ° C. was performed in an Ar atmosphere of 90 kPa or less.

By applying the same brush honing treatment and wet blasting as those in Example 1 to the insert bases made of these TiCN-based cermets F to H according to the process sequence and processing conditions shown in Table 5, the present inventions 6 to 9 and the comparison The insert substrates of Examples 7-9 were prepared.
Further, a hard coating layer of a single TiAlN layer having an average film thickness of 1.5 μm was deposited on the surface of these insert substrates by an arc ion plating method as a 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).
The honing shape by brush honing was round honing with a radius of 0.06 mm.
In addition, the wet blasting process uses the apparatus shown in FIG. 5 (a) in the same manner as in Example 1 (however, the blast gun uses only one that opposes the cutting edge), and excludes the inner surface of the through hole. At least the flank face of the insert and the surface of the chip breaker were treated. Therefore, the inner surface of the through hole of the insert substrate is not subjected to wet blasting, and the hard coating layer is not coated, and the sintered skin on which the metal stagnation layer is formed is maintained.
In addition, since the relief angle of the insert is 7 degrees, if the injection angle is 45 degrees, the angle of ejection of the relief surface and the rake face will be different, and the angle of injection of the rake face will be closer to the right angle. Thus, it is considered that the rake face is given a compressive residual stress equal to or greater than the residual stress measured on the flank face.

The insert bases of the present inventions 6 to 9 and comparative examples 7 to 9 (those before being coated with the hard coating layer) are formed on the inner surface and the flank surface of the through hole and the outermost surface of the chip breaker using an electron microscope. The thickness of the resulting metal stripe layer and the surface occupancy (area ratio) of the layer were measured.
In addition, regarding the insert bases of the present inventions 6 to 9 and Comparative Examples 7 to 9 (before being coated with the hard coating layer), the residual stress of the hard phase on the surface of the insert base is expressed as X on the flat surface of the insert base flank. It was measured with a line diffractometer.
Furthermore, the surface roughness of the flank, chip breaker, and honing part was measured according to JIS B0601-1994 (2001) for the insert bases of the present invention 6-9 and comparative examples 7-9 (before being coated with the hard coating layer). ), The average roughness Ra was measured at a cutoff value of 0.08 mm. Regarding the surface roughness of the chip breaker, the bottom of the breaker was measured.
Table 5 shows the measured values of the surface occupancy ratio (area ratio), the layer thickness, the residual stress, and the surface roughness of the metal stagnation layer in the insert substrate before the hard coating layer is formed.

  Furthermore, for the inserts according to the present invention 6-9 and Comparative Examples 7-9 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 flank, chip breaker, honing part, The results of measuring the surface roughness of the inner surface of the through hole in the same manner as described above are also shown in Table 5.

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 a screw.
<< Cutting Test 2 >> Wet Intermittent Cutting Work Material; JIS-SNCM439 Grooved Round Bar (6 Grooves in the Longitudinal Direction)
Cutting speed: 200 m / min,
Feed: 0.5mm / rev,
Cutting depth: 4mm
The actual cutting time until cutting edge replacement in the cutting test 2 was evaluated.
Table 6 shows the reason for exchanging the cutting edge part together with the actual cutting time until the cutting edge part replacement.
Note that the time until replacement of the cutting edge is until it becomes impossible to continue actual cutting, such as chipping or chipping in the used cutting edge, or severe damage from the inner surface of the through hole that contacts the clamping screw. And when normal cutting was maintained, the time until the flank wear width reached 0.4 mm was used.
<< Cutting Test 3 >> Wet Continuous Cutting Work Material: JIS-SUJ2 Round Bar Cutting Speed: 320 m / min,
Feed: 0.4mm / rev,
Cutting depth: 2mm
In the cutting test 3, the cutting surface at the start of cutting after 0.2 minutes of cutting time was observed.
Table 6 shows the cutting test results in the cutting tests 2 and 3.

According to Table 6, according to the present invention 6-9, the metal stripe layer having a predetermined thickness and a predetermined surface occupation ratio is exposed on the inner surface of the through hole. Because there is no major damage from the inner surface of the through-hole that comes into contact with the support), the metal wrinkle layer is removed from the flank and chip breaker, the surface roughness is improved, and high compressive residual stress is also applied. Also, the used cutting edge part showed a long service life.
In addition, the present inventions 8 and 9 in which the surface roughness of the honing part is further improved as compared with the present inventions 6 and 7 have a longer actual cutting time until the cutting edge part replacement, and it is difficult to obtain a better finished surface. Even with SUJ2 cutting, a good glossy finished surface was obtained.
On the other hand, in Comparative Example 7 in which the flank and the metal breaker layer of the chip breaker are not removed, peeling of the hard coating layer of the cutting edge portion occurs during cutting, thereby welding chips and work material The finished surface became cloudy. In addition, due to the occurrence of the chip welding phenomenon and the insufficient surface roughness and compressive residual stress of the insert, the used cutting edge was also damaged in a short time.
Although the metal stagnation layer is formed inside the through hole, the comparative example 8 having a surface occupancy ratio of only 54 area% is the present invention example 9 having the surface occupancy ratio of 67 area% of the metal stagnation layer inside the through hole. In comparison, it was severely damaged from the inner surface of the through-hole that was in contact with the clamping screw and showed a short life.
In Comparative Example 9 having no metal squeeze layer inside the through hole, it was severely damaged from the inner surface of the through hole in contact with the clamping screw (support) at the initial stage of cutting. For this reason, in Comparative Examples 8 and 9, when there is continuous cutting, it is not possible to replace the other cutting edge portion, and it is necessary to replace the insert itself.

From the results shown in Tables 1 to 6 above, a metal stripe layer having a predetermined layer thickness and a predetermined surface occupancy ratio (area ratio) is formed on the outermost surface portion of the inner surface of the through hole for attaching the insert to the tool body. In addition, the surface covering insert of the present invention in which the metal stripe layer is not covered with the hard coating layer can prevent the occurrence of cracks and breakage on the contact surface with the supporting means that contacts the surface covering insert. The surface roughness of the flank face and chip breaker and the residual stress of the hard phase on the rake face surface are properly adjusted, so it has excellent chipping resistance and finished surface accuracy in high-load cutting. It was confirmed that the cutting performance was excellent over a long period of use and the tool life could be extended.
On the other hand, in the insert of the comparative example in which the metal surface layer having a predetermined surface occupancy (area ratio) and layer thickness is not formed on the outermost surface portion of the inner surface of the through hole for attaching the insert to the tool body, In cutting under load conditions, the inserts were severely damaged from the inner surface of the through hole that contacted the clamping screw at the beginning of cutting, and could not be replaced with other cutting edges. .

An insert substrate (sintered body) made of a TiCN-based cermet was produced in the same manner as the present invention C in Table 1 of Example 1 using raw material powder having the same composition as the raw material used in Example 1. The insert substrate has a metal stagnation layer on the surface, and the layer thickness and surface occupancy of the metal stagnation layer are as described in the invention C in Table 1. Further, the insert substrate was subjected to wet blasting under the conditions shown in Table 7 (except for the inner surface of the through hole). Further, honing (brush honing) was performed on the cutting edge portion of the insert base under the conditions shown in Table 7.
Thereafter, a PVD hard coating layer was formed by arc ion plating with various materials and film thicknesses shown in Table 7 on the surface excluding the inner surface of the through hole in the insert substrate. An insert was obtained. Comparative Example 10 and Comparative Example 11 are examples in which a PVD hard coating layer was formed without wet blasting the insert substrate.
For the insert substrate before the formation of the hard coating layer, the residual stress of the flank and the surface roughness of the flank, chip breaker, and honing part were measured in the same manner as described above. Since the surface roughness of the insert flank, chip breaker, honing portion, and through hole inner surface was measured in the same manner as described above, the results are shown in Table 7.
Next, a cutting test was performed under the following conditions to evaluate the insert performance.
<< Cutting Test 4 >>
Work material: JIS-SNCM439 grooved round bar (6 grooves in the longitudinal direction),
Cutting speed: 160 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 when chipping or chipping occurs on the used cutting edge or the insert breaks from the inner surface of the mounting through hole, and When normal cutting was maintained, the time until the flank wear width reached 0.2 mm was taken.
<< Cutting Test 5 >>
Work material: JIS-S45C round bar,
Cutting speed: 250 m / min,
Feed rate: 0.15 mm / rev,
Cutting depth: 1.0mm
Wet continuous cutting was performed, and the flank wear width after 20 minutes of the actual machining time and the state of the work material finished surface were evaluated.
Table 8 shows the actual cutting time until the cutting edge replacement in the cutting test 4 and the reason for the cutting edge replacement, the flank wear width in the cutting test 5 and the appearance state of the work material finished surface at the end of cutting.

  From the results shown in Table 8, any of the hard coating layers having various different materials and film thicknesses as shown in Table 8 are excellent in chipping resistance in the cutting process in which a high load acts in the example of the present invention. It was confirmed that the tool life and accuracy of the finished surface were excellent, the cutting performance was excellent over a long period of use, and the tool life could be extended. In Comparative Example 10 and Comparative Example 11 in which the insert base was not wet-blasted, it was confirmed that the chipping resistance was inferior and the appearance quality of the finished surface was also inferior.

    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 (20)

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 through hole for mounting, at least a support tool contact surface that comes into contact with a support tool as means for attaching to the tool body is composed of sintered skin not covered with the hard coating layer, and the support tool contact. In the outermost surface portion of the surface, a metal single layer composed of a substantially single phase mainly composed of one or two of Co and Ni has a layer thickness of 0.1 μm or more and 5 μm or less and a surface occupation of 60 area% or more. On the other hand, the flank face of the insert base and the surface of the chip breaker do not have the metal squeeze layer, and the flank face of the insert base and the surface roughness of the chip breaker have a cutoff value. A cutting insert made of titanium carbonitride-based cermet, characterized by an arithmetic average roughness Ra of 0.08 mm being 0.2 μm or less.   The surface-covered titanium carbonitride-based cermet cutting insert according to claim 1, wherein a surface area ratio of the metal stagnation layer on the support contact surface of the through hole is 80 area% or more.   The surface-coated carbonitriding 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 450 MPa or more in compression. Titanium-based cermet cutting insert.   The surface-coated titanium carbonitride-based cermet cutting insert according to claim 3, 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.   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 0.1 μm or less in arithmetic mean roughness Ra at a cutoff value of 0.08 mm. 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 6, 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.   8. The surface-coated titanium carbonitride-based cermet cutting insert according to claim 7, wherein at least one of the hard coating layers is composed 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 7, characterized in that it is a feature.   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 9, 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;
An insert substrate manufacturing process for manufacturing an insert substrate by a sintering method so that a metal stagnation layer composed of a substantially single phase mainly composed of one or two of Co and Ni is formed on the surface;
By subjecting the surface of the insert base to wet blasting within a region excluding the support contact surface that contacts the support as a means for attaching to the tool body in the mounting through hole, the surface portion of the support contact surface The surface of the flank and chip breaker is removed from the flank and chip breaker surface while leaving the metal stubble layer on the surface, and the surface roughness of the flank and chip breaker is calculated as the 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 the support contact surface of the surface of the insert base,
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. The method for producing a surface-coated titanium carbonitride-based cermet cutting insert according to claim 11, wherein at least the surface of the insert substrate excluding the contact surface with the support 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 12.   14. The method for producing a surface-coated titanium carbonitride-based cermet cutting insert according to claim 13, wherein, in the wet blasting step, the injection 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 after the completion of the wet blasting process and before the covering process, according to any one of claims 11 to 14. 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 honing portion in the insert base is 0.1 μm or less in terms of arithmetic average roughness Ra at a cutoff value of 0.08 mm. 15. The method for producing the surface-coated titanium carbonitride-based cermet cutting insert according to 15.   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 11. A layer formed of one or two or more compounds composed of at least one element selected from nitrogen, oxygen, and boron is formed by physical vapor deposition. The method for producing a surface-coated titanium carbonitride-based cermet cutting insert according to any one of claims 16.   18. The method for producing a surface-coated titanium carbonitride-based cermet cutting insert according to claim 17, 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 manufacturing a surface-coated titanium carbonitride-based cermet cutting insert according to claim 17, 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. 20. The method for producing a surface-coated titanium carbonitride-based cermet cutting insert according to claim 19, wherein a 1.0 [mu] m TiN layer is formed in that order.

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