JP5978671B2 - Replaceable cutting edge - Google Patents

Description

  The present invention relates to a blade-tip-exchangeable cutting tip. More specifically, the present invention relates to a cutting edge-exchangeable cutting tip that has a wide range of uses and is particularly effective in steel processing and cast iron processing.

  2. Description of the Related Art Conventionally, various work materials have been cut by attaching a blade-tip-exchangeable cutting tip to a tip portion (blade tip) of a cutting tool. When the blade-tip-exchangeable cutting tip reaches the end of its life by using the cutting tool for a long period of time, the blade-tip-exchangeable cutting tip is replaced at that time and cutting is continued.

  Such cutting edge-replaceable cutting tips are required not only to have high cutting performance such as wear resistance, toughness, and heat crack resistance, but also to have a tool shape with excellent chip disposal. . In order to satisfy the required performance, a cemented carbide or cermet known as a hard material is used for the cutting edge exchange type cutting tip.

  The above cemented carbide is composed of a WC powder mainly containing tungsten carbide (WC), a binder phase for bonding the WC powders, and an IVa group element, a Va group element, and a VIa group element in the periodic table as necessary. Mainly composed of a compound phase or a solid solution phase composed of at least one compound selected from the group consisting of at least one element selected from the group consisting of and at least one element selected from the group consisting of carbon, nitrogen, oxygen and boron. After mixing the powder, it is molded by pressing, injection molding, or extrusion, and the molded body is placed on a sintering plate, placed in a sintering furnace, and liquid phase sintering to produce a sintered body. Is obtained.

  The cermet is at least one selected from the group consisting of titanium carbide and / or nitride and / or carbonitride as a main component, Group IVa element, Group Va element and Group VIa element in the periodic table. And a powder mainly composed of a compound phase or a solid solution phase composed of one or more compounds selected from the group consisting of carbon and nitrogen, oxygen and boron, and at least one element selected from the group consisting of carbon, nitrogen, oxygen and boron. After mixing with a binder phase made of iron-based metal, it is molded by pressing, injection molding, or extrusion, and the molded body is placed on a sintering plate and placed in a sintering furnace, followed by liquid phase sintering. It is obtained by producing a sintered body.

  And, if necessary, the surface of the sintered body is partially or fully polished with a grindstone, and further, blade edge treatment, hard layer coating on the surface of the sintered body, surface treatment after coating, etc. Thus, a blade-tip-exchangeable cutting tip is produced.

  However, in the liquid phase sintering described above, sintering does not proceed uniformly due to the density of the composition due to the part of the molded body and the sintering temperature and / or atmospheric gas concentration due to the part of the molded body. In many cases, the shrinkage varies depending on the part of the molded body. Further, deformation may occur during sintering due to the influence of gravity according to the shape of the molded body. In particular, cemented carbides and cermets have a volume shrinkage of about 50% due to liquid phase sintering, so the difference in the amount of shrinkage due to the site is significant, and the shape and dimensions of the sintered body may vary ( Non-patent document 1).

  If there is variation in the shape and dimensions of the sintered body in this way, in the holder that holds the cutting edge replaceable cutting tip, the position of the cutting edge is slightly shifted before and after the replacement of the cutting edge replaceable cutting tip. There is a problem that the surface quality deteriorates. Such a problem becomes particularly remarkable in milling processing in which a plurality of blade-tip-exchangeable cutting tips are used simultaneously.

  In particular, because the shape of the cutting edge-exchangeable cutting tip has become complicated in recent years, for example, in powder feeding to a die during pressing, a portion where there is a large amount of powder feeding, that is, a portion where the molded body density is high, has a small shrinkage due to sintering, A site where there is little powder supply, that is, a site where the molded body density is low, has a large shrinkage amount due to sintering. As described above, the amount of shrinkage varies depending on the region, and as a result, the sintered body changes from a completely similar shape to a shape having distortion.

  In order to eliminate such variations in the shape and dimensions of the sintered body, a part or all of the surface of the sintered body is polished with a grindstone after sintering to make the size of the sintered body uniform. It is. However, the cutting edge-exchangeable cutting tip formed by press molding often has a three-dimensionally complicated shape. Such a complicated shape cannot be formed by polishing, and even if it can be made industrially Is extremely disadvantageous. On the other hand, it is often the case that the dimensions of all the cutting edge-replaceable cutting tips cannot be made uniform only by partial polishing of a flat portion such as a tip holding surface in a holder.

  Therefore, in Patent Documents 1 to 8, in order to increase the dimensional accuracy of the blade-tip-exchangeable cutting tip, a dispersing agent is mixed when forming the molded body to make the density of the molded body as uniform as possible. Moreover, in patent documents 9-13, in order to manufacture a complicated and highly accurate blade-tip-exchange-type cutting tip, the effort which reduces a grinding | polishing location as much as possible is made, or the effort of non-polishing is made.

  However, even with the techniques disclosed in Patent Documents 1 to 13, the distortion (deformation) due to the variation in shrinkage due to the site of the molded body during sintering cannot be solved. At present, the cutting edge-exchangeable cutting tip has not reached a level that satisfies the cutting performance and dimensional accuracy required by the user.

JP 2006-176800 A JP 2001-081525 A JP 2003-293071 A JP 2008-183708 A JP 2008-126403 A Japanese Examined Patent Publication No. 62-056944 JP-T-2004-509773 Special table 2009-519139 gazette JP 2006-075913 A JP 2006-088332 A JP 05-138447 A Japanese Patent Publication No. 07-002284 Japanese Patent Publication No. 01-038602

Liquid Phase Sintering Publisher: Uchida Otsutsuru Co., Ltd. 1-12, 71, 79-85, 98-99, 223, 276-278 ISBN 4-7536-5187-8

  In order to prevent deformation of the sintered body during liquid phase sintering, the temperature and atmosphere of each part of the molded body in the sintering process should be as uniform as possible so that the sintering proceeds in the same way in all parts. It is effective. However, in practice, there is a limit in making the progress of sintering in each part the same, and there is a limit in the existing technology, and the appearance of a cutting edge-exchangeable cutting tip having excellent dimensional accuracy is awaited.

  The present invention has been made in view of the current situation as described above, and an object of the present invention is to provide a blade-tip-exchangeable cutting tip having excellent cutting performance and high dimensional accuracy.

  In order to solve the above-mentioned problems, the present inventors have conducted extensive research on the cause of impairing the dimensional accuracy of cemented carbide and cermet. By controlling the amount of carbon contained in each part of the sintered body, it is possible to replace the cutting edge. The present inventors have found that it is possible to achieve both cutting performance and dimensional accuracy of the die cutting tip.

  That is, the present invention is a blade-tip-exchangeable cutting tip made of cemented carbide or cermet, and the blade-tip-exchangeable cutting tip is composed of an outer peripheral portion located on the surface side and a core portion located on the inner side. The outer peripheral portion is characterized in that the content of free carbon is lower than the content of free carbon contained in the core portion.

  Here, the outer peripheral portion is a region where free carbon is less than C02 defined by CIS 006C-2007, which is a porosity classification standard for super hard alloys, and the core portion has free carbon of C02 or higher. Preferably, the outer peripheral portion does not contain free carbon.

The cemented carbide is
i) tungsten carbide;
ii) at least one element selected from the group consisting of group IVa elements, group Va elements and group VIa elements of the periodic table; and at least one element selected from the group consisting of carbon, nitrogen, oxygen and boron; A compound phase or a solid solution phase composed of one or more compounds composed of:
iii) a binder phase composed of one or more iron group elements;
iv) consists of inevitable impurities,
The compound phase or solid solution phase is contained in the range of 0.1 to 50% by mass,
The binder phase is preferably contained in the range of 3 to 30% by mass.

The cemented carbide is
i) tungsten carbide;
ii) a binder phase composed of one or more iron group elements;
iii) consists of inevitable impurities,
The binder phase is preferably contained in the range of 1 to 30% by mass.

The cermet
i) at least one element selected from the group consisting of group IVa elements, group Va elements and group VIa elements of the periodic table, and at least one element selected from the group consisting of carbon, nitrogen, oxygen and boron; A compound phase or a solid solution phase composed of one or more compounds composed of:
ii) a binder phase composed of one or more iron group elements;
iii) consists of inevitable impurities,
The compound phase or solid solution phase is contained in the range of 70 to 97% by mass,
The binder phase is preferably contained in the range of 3 to 30% by mass.

Moreover, it is preferable that the surface portion of the blade-tip-exchangeable cutting tip is a non-ground surface.
The blade-tip-exchangeable cutting tip preferably has a coating on the surface, and the coating is at least selected from the group consisting of IVa group element, Va group element, VIa group element, Al, and Si in the periodic table. It is preferable to include one or more layers composed of one element or a compound of the element and at least one element selected from the group consisting of carbon, nitrogen, oxygen and boron. The coating is preferably formed by physical vapor deposition and / or chemical vapor deposition.

  Further, the coating is formed by physical vapor deposition and includes a super multi-layer structure layer or a modulation structure layer, and the super multi-layer structure layer includes the IVa group element, the Va group element, and the VIa group in the periodic table. Two or more kinds of compounds composed of at least one element selected from the group consisting of elements, Al, and Si and at least one element selected from the group consisting of carbon, nitrogen, oxygen, and boron The unit layer has a structure in which each unit layer is periodically and repeatedly laminated with a thickness of 0.2 nm or more and 20 nm or less, and the modulation structure layer includes IVa group element, Va group element, VIa group element, Al in the periodic table. And a compound consisting of at least one element selected from the group consisting of Si and at least one element selected from the group consisting of carbon, nitrogen, oxygen, and boron. Composition or composition ratio of preferably has a structure that changes at a period of 0.2nm or 40nm or less in the thickness direction.

Moreover, it is preferable that the compressive residual stress of 0.1 GPa or more is given to this film.
Moreover, it is preferable that this blade edge | tip-exchange-type cutting tip is used for milling, and it is preferable to cut using two or more simultaneously.

  Moreover, it is preferable that this blade edge | tip-exchange-type cutting tip is a positive type, and it is preferable that the through-hole for attaching to a holder with a screw | thread is formed.

  The cutting edge replacement type cutting tip of the present invention has the above-described configuration, and thus has an effect of excellent cutting performance and high dimensional accuracy.

Hereinafter, the present invention will be described in more detail.
<Cutting edge type cutting tip>
The cutting edge replacement type cutting tip of the present invention is made of cemented carbide or cermet. Such a blade-tip-exchangeable cutting tip is composed of two regions, an outer peripheral portion located on the surface side and a core portion located on the inner side, and the outer peripheral portion has a free carbon content in the core. It is characterized by being lower than the content of free carbon contained in the part.

  Such a blade-tip-exchangeable cutting tip is usually produced by liquid phase sintering. At the time of its production, it is placed on a plate and sintered, etc. In this case, there is a difference in the content of free carbon between the portion in contact with the plate and the portion not in contact with the plate. It has been found. And according to the difference in the free carbon content, there is a difference in the amount of shrinkage during sintering of the sintered body (that is, the cutting edge exchangeable cutting tip), which is one of the causes of damaging dimensional accuracy. I understood.

  In order to prevent a difference in free carbon in the sintered body, it can be considered that free carbon exists in the entire sintered body in a supersaturated state. This is because free carbon moves under the influence of external factors such as contact with the plate, and as a result, a concentration gradient (gradient) is considered to occur. This is because movement due to such external factors can be suppressed.

  However, if free carbon is present in a supersaturated state in the entire sintered body, the hardness decreases particularly in the surface portion, and when a film is formed on the surface, the adhesion with the film decreases, As a result, the cutting performance is degraded.

  Therefore, the present invention correctly balances these contradictory characteristics by making the content of free carbon in the outer peripheral portion of the cutting edge replaceable cutting tip lower than the content of free carbon in the core portion. Therefore, it is preferable that the free carbon content in the outer peripheral portion is as small as possible, and it is preferable that free carbon is not included. On the other hand, the closer the free carbon content in the core portion is to the supersaturated state, the better.

  In addition, although an outer peripheral part here is an area | region located in the surface side among 2 area | regions which comprise the blade-tip-exchange-type cutting tip of this invention, the said area | region respond | corresponds to the shape and magnitude | size of a blade-tip-exchange-type cutting tip. Therefore, it is difficult to specify with specific geometric values. However, if this outer peripheral portion is deliberately defined, it can be a region having a thickness of about 3 μm to 1 mm from the surface toward the inside. In the cutting edge-exchangeable cutting tip of the present invention, the region other than the outer peripheral portion (that is, the region located inside the outer peripheral portion) is the core portion. Thus, the cutting edge replacement type cutting tip of the present invention has a configuration in which the core portion is covered with the outer peripheral portion.

  Although depending on the shape and size of the cutting edge-exchangeable cutting tip, the wear resistance tends to deteriorate when the thickness of the outer peripheral portion is less than 3 μm, and the dimensional accuracy tends to deteriorate when it exceeds 1 mm. The thickness of the outer peripheral portion is more preferably 3 to 500 μm, further preferably 3 to 100 μm, and most preferably 3 to 30 μm. In addition, it is preferable to observe in the site | part which functions as a tool with a metal microscope or an electron microscope, after cutting and lapping the blade-tip-exchange-type cutting tip, and measuring the thickness of such an outer peripheral part.

  In addition, as for the blade-tip-exchange-type cutting tip of this invention, it is preferable that the surface part is a non-grinding surface. This is because it is industrially advantageous because the thickness of the outer peripheral portion can be easily controlled and can cope with a complicated three-dimensional shape. However, it is also possible to perform brush processing, barrel processing, or blast processing that facilitates processing into a three-dimensional shape surface with respect to the surface portion of the cutting edge-exchangeable cutting tip.

  Such a blade-tip-exchangeable cutting tip of the present invention is made of cemented carbide or cermet. Moreover, the film may be formed in the surface (namely, on outer peripheral part). Such a coating may cover the entire surface of the blade-tip-exchangeable cutting tip, or may partially cover the surface.

  In addition, as long as such a basic configuration is provided, the shape of the blade-tip-exchangeable cutting tip is not particularly limited and may have any conventionally known shape. As one of such shapes, a positive type can be cited as a suitable shape. This is because, in general, a positive-type blade-tip-exchangeable cutting tip is often used for light cutting when used for milling or turning, and a high dimensional accuracy is required for the tool in the light cutting application.

  Such a blade-tip-exchangeable cutting tip of the present invention includes, for example, drilling, end milling, milling, milling, turning, metal saw processing, cutting tool processing, reaming processing, tapping processing. Or for pin milling of a crankshaft or the like.

  Among the above-described processing, it is preferable to use for milling, and it is preferable to use for cutting using two or more blade-exchangeable cutting tips at the same time. Therefore, it is particularly preferable to apply the present invention to milling using a plurality of (two or more) replaceable cutting tips at the same time.

  This is because when milling is performed using the cutting edge-replaceable cutting tip of the present invention, not only the work surface quality (gloss and dimensional accuracy) of the work material can be improved, but also the tool life can be extended. is there. In addition, when a plurality of cutting edge-exchangeable cutting tips are mounted on a milling holder, if any one of the cutting edge-exchangeable cutting tips is mounted in a protruding state compared to other cutting edge-exchangeable cutting chips. Then, since the cutting amount of the chip is relatively large at the time of cutting, the load becomes high and the chipping is likely to occur. Further, once the chip is lost, the load of the chip that is in the next protruding state becomes extremely high, so that the chip is lost next time.

  Thus, when even one piece has a cutting edge defect of the cutting edge exchange type cutting tip, the chip cutting edge chipping occurs one after another, and the life of the cutting edge exchange type cutting tip is shortened. However, when a tool with high dimensional accuracy such as the blade-tip-exchangeable cutting tip of the present invention is used, there is no projecting state even when a plurality of tools are mounted on the holder as described above. Since the cutting load is equally applied to all the cutting edges, the cutting edge is less likely to be lost, and there is an advantage that the life of the cutting edge-exchangeable cutting tip is extremely long.

  In addition, when the blade-tip-exchangeable cutting tip of the present invention is attached to the holder as described above, it is preferable that a through hole for attaching to the holder with a screw is formed. In addition, when attaching to a holder with a screw in this way, the cutting edge position cannot be finely adjusted for structural reasons, so the merit of using a tool with high dimensional accuracy like the cutting edge replacement type cutting tip of the present invention is increased. .

<Free carbon>
As described above, the blade-tip-exchangeable cutting tip of the present invention is characterized in that the content of free carbon in the outer peripheral portion thereof is lower than the content of free carbon contained in the core portion. Thus, the smaller the free carbon content in the outer periphery, the better, and ideally no free carbon. On the other hand, the closer the free carbon content in the core portion is to the supersaturated state, the better.

  When the whole blade-tip-exchange-type cutting tip contains free carbon, the cutting performance decreases as described above. This is thought to be due to the fact that the hardness of cemented carbides and cermets containing free carbon is reduced, so that the wear resistance is reduced. In addition, when a film is formed on the surface of the blade-tip-exchangeable cutting tip, it is considered that the adhesion strength between the blade-tip-exchangeable cutting tip (base material) and the coating is reduced.

  Therefore, in the present invention, only the outer peripheral portion, which is the surface portion of the blade-tip-exchangeable cutting tip, is in a state that does not contain free carbon or a state in which the free carbon content is extremely low, so that excellent dimensional accuracy and cutting performance It has succeeded in making it compatible.

  As described above, as a method of making the free edge carbon-free state or the state of free carbon content extremely small in the outer peripheral portion of the blade-tip-exchange-type cutting tip, powders having different carbon contents are prepared by injection molding or laminating press. There is no particular limitation such as a method of bonding or an alloy containing free carbon and an alloy not containing free carbon. However, there is an industrial method in which the atmosphere in the cooling process during sintering is a decarburizing atmosphere or a method in which the sintered body that has been sintered is heated again in a decarburizing atmosphere and only carbon on the surface portion is diffused and discharged. Is advantageous. In the case where a film is formed on the surface, this reheating can be performed in the same equipment as the equipment for forming the film as a pretreatment for forming the film.

  More specifically, for example, in the above cooling step, by cooling or holding at a temperature or atmosphere at which free carbon can be sufficiently diffused, a state in which free carbon is not contained in the outer peripheral portion of the blade-tip-exchangeable cutting tip or The content of free carbon can be made extremely low. If the cooling rate is too fast, free carbon cannot be sufficiently diffused. Conversely, if the cooling rate is too slow, the thickness of such an outer peripheral portion may become too thick. Further, when the temperature is temporarily held during the cooling process, the thickness of the outer peripheral portion can be adjusted by the balance between the holding temperature and the holding time. Thus, by controlling the cooling rate, holding temperature, and holding time, the amount of free carbon in the outer peripheral portion and the core portion and the thickness of the outer peripheral portion can be controlled. Also, by controlling the type and pressure of the atmospheric gas, the amount of free carbon and the thickness of the outer peripheral portion and the outer peripheral portion can be controlled in the same manner as described above.

  In the cutting edge-exchangeable cutting tip of the present invention, the outer peripheral portion is a region where free carbon is less than C02 defined by CIS 006C-2007, which is a porosity classification standard for super hard alloys, and the core portion Is preferably a region where the free carbon is C02 or more. CIS is a standard for carbide tools.

  As described above, the outer peripheral portion preferably has a free carbon amount less than C02, and preferably does not contain free carbon (ie, includes zero). On the other hand, the free carbon in the core portion is preferably C02 or more, more preferably C02 to C08 (in the present invention, notation of C04, C06, C08, etc. is used in addition to C02, but all of them are CIS 006C- It is defined by 2007. Note that the larger the number used, such as C02 to C08, the greater the amount of free carbon.

  When the free carbon becomes C02 or more in the outer peripheral portion, the wear resistance may decrease as described above. In addition, if the free carbon is less than C02 in the core portion, the effect of improving the dimensional accuracy is reduced, and if it exceeds C08, a chemical reaction with the sintered plate is likely to occur, which may cause deterioration of the dimensional accuracy.

  CIS 006C-2007 stipulates that a microscope using a metal microscope is performed at a magnification of 100 times, but can be performed by any of the following methods.

  First, the first method is to take a photograph at 100 times as specified, and if necessary, take a tissue photograph of the outer periphery with multiple fields of view until it is the same size as the picture in Appendix 3 of CIS 006C-2007. This is a method of determining by combining. In addition, this method can also make a comparison by trimming the photographs in Appendix 3 so as to have the same area as the photographed photograph.

  The second method is a method in which the taken tissue photograph is converted to a magnification equivalent to 100 times using image correction software and compared with the photograph in Appendix 3 of CIS 006C-2007.

  As a third method, the photograph shown in Appendix Table 3 of CIS 006C-2007 is converted into the image magnification equivalent to the determination.

  Thus, identification of free carbon may be performed by adopting any of the above methods. This is because, when the thickness of the outer peripheral portion is thin, it may be preferable to increase the magnification as necessary to take a photograph.

  In the present invention, the boundary between the “outer peripheral portion” and the “core portion” is a portion where a difference of one or more stages occurs in CIS 006C-2007 (for example, a portion where a difference between “C00” and “C02” occurs, C02 ”and“ C04 ”). When the above differences occur continuously and it is difficult to identify the boundary, the boundary between the two points where the difference of one or more levels clearly occurs is assumed as the boundary.

<Composition of cutting edge exchange type cutting tip>
The cutting edge replacement type cutting tip of the present invention is made of cemented carbide or cermet. The composition of the cemented carbide or the composition of the cermet is not particularly limited, and a conventionally known composition can be adopted. For example, it is preferable to employ one having the following composition.

That is, as a cemented carbide,
i) tungsten carbide;
ii) At least one selected from the group consisting of group IVa elements (Ti, Zr, Hf, etc.), group Va elements (V, Nb, Ta, etc.) and group VIa elements (Cr, Mo, W, etc.) of the periodic table A compound phase or a solid solution phase composed of one or more compounds composed of a seed element and at least one element selected from the group consisting of carbon, nitrogen, oxygen and boron;
iii) a binder phase composed of one or more of iron group elements (referred to as Fe, Co, Ni, also referred to as iron-based metal);
iv) consists of inevitable impurities,
The compound phase or the solid solution phase may be included in a range of 0.1 to 50% by mass, and the binder phase may be included in a range of 3 to 30% by mass. Here, in the present invention, the “compound phase or solid solution phase” means that a compound constituting such a phase may form a solid solution or may exist as an individual compound without forming a solid solution. Indicates.

  The compound phase or solid solution phase is more preferably contained in the range of 2 to 20% by mass, and the binder phase is more preferably contained in the range of 3 to 15% by mass.

In addition, as a cemented carbide,
i) tungsten carbide;
ii) a binder phase composed of one or more iron group elements;
iii) consists of inevitable impurities,
Examples of the binder phase include those having a composition contained in the range of 1 to 30% by mass. The binder phase is more preferably 2 to 20% by mass.

On the other hand, as a cermet,
i) at least one element selected from the group consisting of group IVa elements, group Va elements and group VIa elements of the periodic table, and at least one element selected from the group consisting of carbon, nitrogen, oxygen and boron; A compound phase or a solid solution phase composed of one or more compounds composed of:
ii) a binder phase composed of one or more iron group elements;
iii) consists of inevitable impurities,
The compound phase or the solid solution phase may be included in a range of 70 to 97% by mass, and the binder phase may be included in a range of 3 to 30% by mass.

  The compound phase or solid solution phase is more preferably contained in the range of 82 to 97% by mass, and the binder phase is more preferably contained in the range of 3 to 18% by mass.

The cemented carbides and cermets specifically mentioned above are preferred because they are industrially significant. The compound phase or solid solution phase may include a plurality of phases having different compositions, and a phase that does not form a solid solution (for example, WC, Mo ₂ C, etc.) may exist alone.

In the above cemented carbide, “at least one element selected from the group consisting of group IVa element, group Va element, and group VIa element of the periodic table, and a group consisting of carbon, nitrogen, oxygen and boron” is selected. Examples of the “compound composed of at least one element” include TiC, TaC, NbC, ZrC, HfC, TiN, TaN, ZrN, HfN, TiCN, ZrCN, TaNbC, VC, Cr ₃ C _{2 and the} like. be able to. Among the above compounds, those having a B1-type crystal structure are preferred.

Further, in the cermet, “at least one element selected from the group consisting of group IVa element, group Va element and group VIa element of the periodic table and at least one element selected from the group consisting of carbon, nitrogen, oxygen and boron” is used. the compound "composed of a kind of element, cited for example _{(Ti a W b Mo c Ta} d Nb e V f Zr g Cr h) x (C i B j N k O l) represented by _y compound And a to l, x, and y in the formula vary depending on the site of tissue. Among the above compounds, those having a B1-type crystal structure are preferred.

  The composition ranges of the cemented carbide and cermet are generally industrially produced ranges, but may exceed this range, and the ratio of the binder phase may vary depending on the site.

  Further, the effect of the present invention is exhibited even if the cemented carbide contains an abnormal phase locally called η phase in the structure. Note that the cutting edge-exchangeable cutting tip of the present invention may have a de-β layer, a Co-enriched layer, or a surface hardened layer formed on the surface thereof, and even if the surface is modified in this way, the effect of the present invention is achieved. Is indicated.

<Coating>
The cutting edge-exchangeable cutting tip of the present invention can have a coating on the surface. Such a film may be formed so as to cover the entire surface of the blade-tip-exchangeable cutting tip, or may be formed so as to cover only a part of the blade-tip-exchangeable cutting tip. It is preferable to cover at least a part of the part that contributes to the improvement of the cutting performance even when the entire surface or a part of the tool is covered because of improvement of various characteristics of the tool (that is, improvement of cutting performance).

  In the present invention, when a film is formed on the blade-tip-exchangeable cutting tip, the blade-tip-exchangeable cutting tip itself may be referred to as a base material.

  By covering the cutting edge replaceable cutting tip with the coating in this manner, various characteristics such as wear resistance, oxidation resistance, toughness, and coloring for identifying the used cutting edge portion are improved. The action is given.

  Such coatings include Group IVa elements (Ti, Zr, Hf, etc.), Group Va elements (V, Nb, Ta, etc.), Group VIa elements (Cr, Mo, W, etc.), Al, and Si of the periodic table. Including at least one element selected from the group consisting of or a compound of the element and at least one element selected from the group consisting of carbon, nitrogen, oxygen, and boron. preferable.

Examples of such elements or compounds include TiCN, TiN, TiCNO, TiO ₂ , TiNO, TiB ₂ , TiBN, TiSiN, TiSiCN, TiAlN, TiAlCrN, TiAlSiN, TiAlSiCrN, AlCrN, AlCrCN, AlCrVN, TiAlBN, TiBCN, TiAlBCN , TiSiBCN, AlN, AlCN, Al 2 O 3, ZrN, ZrCN, ZrN, ZrO 2, HfC, HfN, HfCN, NbC, NbCN, NbN, Mo 2 C, WC, W 2 C, Cr, Al, Ti, Si , V and the like. Further, the above element or compound may be doped with a small amount of other elements. In these compositions, each atomic ratio follows the above general formula. In the present invention, when the compound is represented by the chemical formula as described above, it is assumed that all the conventionally known atomic ratios are included unless the atomic ratio is particularly limited, and are not necessarily limited to those in the stoichiometric range. . For example, when simply describing “TiCN”, the atomic ratio of “Ti”, “C”, and “N” is not limited to 50:25:25, and also when “TiN” is described, “Ti” and “N” Is not limited to the case of 50:50, and any conventionally known atomic ratio is included. In addition, TiCN includes MT-TiCN using a known chemical vapor deposition method (CVD method) (in the present invention, “MT” indicates that it is formed by a low temperature CVD method).

  And it is especially preferable that at least one layer of such a coating has a compressive residual stress. Thereby, the extremely excellent effect that the toughness of the coating is remarkably improved and the propagation of cracks generated during the cutting process can be effectively prevented is shown. In this way, at least one layer of the coating has a compressive residual stress, and the coating includes a super multi-layer structure layer or a modulation structure layer, which will be described later, so that they act synergistically and have extremely high wear resistance and toughness. Both can be achieved.

  The film of the present invention can be formed by a conventionally known physical vapor deposition method (PVD method), chemical vapor deposition method (CVD method), vacuum vapor deposition method, sputtering method, plasma CVD method or the like. It is more preferable to form by chemical vapor deposition, and physical vapor deposition is more preferable in that it can easily introduce compressive residual stress and can improve cutting performance.

  As such a physical vapor deposition method, any conventionally known physical vapor deposition method can be adopted and is not particularly limited. Examples of such physical vapor deposition include magnetron sputtering, arc ion plating, holocathode, ion beam, electron beam, balanced magnetron sputtering, unbalanced magnetron sputtering, and dual magnetron sputtering. Can be mentioned.

  Among the methods exemplified above, it is particularly preferable to employ the arc type ion plating method. This is because compressive residual stress can be applied to the coating very effectively. In addition, it is preferable to employ | adopt the apparatus which provided each ion source used for the above methods as an apparatus which performs a physical vapor deposition method. It should be noted that even after the coating is formed, a part of the coating may be removed by brushing, barreling, blasting, diamond grindstone, laser processing, or the surface of the coating may be subjected to surface treatment such as smoothing processing. The effect is not lost. Moreover, you may give a compressive residual stress to a film using surface treatment methods, such as a dry shot blast process, a wet shot blast process, a brush process, a barrel process, and laser processing.

  Here, the compressive residual stress is a kind of internal stress (intrinsic strain) existing in such a film, and is represented by a numerical value “−” (minus) (unit: “GPa” is used in the present invention). Stress. For this reason, the concept that the compressive residual stress is large indicates that the absolute value of the numerical value is large, and the concept that the compressive residual stress is small indicates that the absolute value of the numerical value is small. Incidentally, the tensile residual stress is a kind of internal stress (intrinsic strain) existing in the film, and means a stress represented by a numerical value “+” (plus). Note that the term “residual stress” includes both compressive residual stress and tensile residual stress.

  And it is preferable that the compressive residual stress whose absolute value is 0.1 GPa or more is given to the film of this invention, More preferably, it is 0.2 GPa or more, More preferably, it is 0.5 GPa or more. If the absolute value is less than 0.1 GPa, sufficient toughness may not be obtained, and the above excellent effects may not be obtained. On the other hand, the larger the absolute value, the better from the viewpoint of imparting toughness. However, when the absolute value exceeds 6 GPa, the coating itself may be broken or peeled off, which is not preferable.

Such compressive residual stress (residual stress) can be measured by the sin ² ψ method using an X-ray stress measurement apparatus. Such compressive residual stress is an arbitrary point (1 point, preferably 2 points, more preferably 3 to 5 points, more preferably 10 points (multiple points) included in the layer to which the compressive residual stress in the coating is applied. The points in the measurement are preferably selected with a distance of 0.1 mm or more apart from each other so that the stress of the layer can be represented by the sin ² ψ method. It can be measured by obtaining.

The sin ² ψ method using X-rays is widely used as a method for measuring the residual stress of a polycrystalline material. For example, “X-ray stress measurement method” (Japan Society of Materials Science, 1981 Corporation) The method described in detail on pages 54 to 67 of Yokendo) may be used.

  The compressive residual stress can also be measured by using a method using Raman spectroscopy. Such Raman spectroscopy has the merit that local measurement can be performed in a narrow range, for example, a spot diameter of 1 μm. The measurement of residual stress using such Raman spectroscopy is common, but for example, "Thin film mechanical property evaluation technique" (Sipec (currently renamed Realize Science and Technology Center), published in 1992. ), Pages 264 to 271 can be employed.

  Furthermore, the compressive residual stress can also be measured using synchrotron radiation. In this case, there is a merit that the distribution of residual stress can be obtained in the thickness direction of the coating.

  In addition, it is preferable that the thickness of the film of the present invention (when formed with two or more layers, the total thickness) is 1 μm or more and 30 μm or less, and more preferably 2 μm or more and 20 μm or less. If the thickness is less than 1 μm, the effect of improving the wear resistance is not sufficiently exhibited. On the other hand, if the thickness exceeds 30 μm, no further improvement in various properties is observed, which is not economically advantageous. However, as long as economic efficiency is ignored, the thickness can be 30 μm or more, and the effect of the present invention is shown. As a method for measuring such thickness, for example, a cutting edge-exchangeable cutting tip on which a film is formed is cut, and the cross section is scanned with a scanning electron microscope (SEM) or a transmission electron microscope (TEM). It shall be measured by The composition of the film is measured by an energy dispersive x-ray spectrometer (EDS).

  In addition, the coating film of the present invention is formed by physical vapor deposition, and preferably includes a super multi-layer structure layer or a modulation structure layer. Hereinafter, these will be described.

<Super multilayer structure layer>
The super multi-layer structure layer of the present invention is composed of IVa group elements (Ti, Zr, Hf, etc.), Va group elements (V, Nb, Ta, etc.), VIa group elements (Cr, Mo, W, etc.), Al, etc. And at least one unit layer composed of a compound comprising at least one element selected from the group consisting of Si and at least one element selected from the group consisting of carbon, nitrogen, oxygen, and boron. , Each of which has a structure in which the layers are periodically and repeatedly stacked with a thickness of 0.2 nm to 20 nm.

  Here, the term “repetitively laminating” means having a certain periodicity, for example, when laminating two types of unit layers alternately up and down, or when laminating three types of unit layers repeatedly upper, middle, and lower. It means to laminate. If the thickness of each unit layer is less than 0.2 nm or exceeds 20 nm, the effect of improving the wear resistance by the super multi-layer structure layer may not be shown. The thickness of each unit layer can be appropriately adjusted depending on the composition constituting the unit layer and the film forming conditions. Each unit layer may have substantially the same thickness or may have a different thickness.

The unit layer is composed of at least one element selected from the group consisting of group IVa elements, group Va elements, group VIa elements, Al, and Si in the periodic table, and carbon, nitrogen, oxygen, and boron. Examples of the compound composed of at least one element selected from the group consisting of TiC, TiN, TiCN, TiNO, TiCNO, TiB ₂ , TiO ₂ , TiBN, TiBNO, TiCBN, ZrC, ZrO ₂ , HfC, HfN, TiAlN , TiAlCrN, TiZrN, TiCrN, AlCrN , CrN, VN, TiSiN, TiSiCN, AlTiCrN, TiAlCN, ZrCN, ZrCNO, Al 2 O 3, AlN, AlCN, ZrN, TiAlC, NbC, NbN, NbCN, Mo 2 C, WC, W ₂ C and the like can be mentioned.

  The number of unit layers constituting the super multi-layer structure layer (total number of layers) is not particularly limited, but is usually preferably 10 or more and 5000 or less. If it is less than 10 layers, the crystal grains in each unit layer are coarsened, so that the hardness of the coating may be reduced. If it exceeds 5000 layers, each unit layer becomes too thin and tends to be mixed. is there.

  Such a super multi-layer structure layer is formed by a conventionally known physical vapor deposition method, and its production method is not particularly limited as long as it is formed by a physical vapor deposition method. Hereinafter, the case where the arc ion plating method is employed as the physical vapor deposition method will be exemplified.

  First, in the arc ion plating film forming apparatus, targets are set in a plurality of evaporation sources corresponding to the types of unit layers to be formed. Then, the substrate is set in the substrate holder in the chamber of the apparatus, and the target of the evaporation source is evaporated and ionized while rotating the substrate holder so as to face the evaporation source. Form. An example of more specific conditions is as follows.

  That is, the base material is heated by a heater installed in the chamber. Thereafter, the substrate surface is cleaned with argon ions for 1 to 120 minutes by introducing a bias voltage to the substrate while introducing argon gas and maintaining the pressure in the chamber at 1 to 10 Pa.

  Subsequently, after the argon gas in the chamber is exhausted, the reaction gas is introduced, and while maintaining the pressure in the chamber at 2 to 10 Pa, the substrate holder on which the substrate is set is rotated while the bias voltage ( -20 to -200 V) is applied, and the target set in the evaporation source is ionized, and the unit layers are sequentially stacked to form a super multi-layer structure layer.

<Modulation structure layer>
The modulation structure layer of the present invention includes at least one element selected from the group consisting of group IVa elements, group Va elements, group VIa elements, Al, and Si in the periodic table, and carbon, nitrogen, oxygen, and boron. It is comprised by the compound which consists of at least 1 sort (s) of elements chosen from the group which consists of, and the composition or composition ratio of the compound has a structure which changes with a period of 0.2 nm or more and 40 nm or less in the thickness direction. By forming the modulation structure layer as a coating in this way, extremely excellent wear resistance can be imparted.

  Here, the change in the composition or composition ratio of the compound in the thickness direction with a period of 0.2 nm or more and 40 nm or less means that, for example, the states of A and B types having the same constituent elements but different composition ratios are modulated. In the thickness direction from the base material (blade-exchangeable cutting tip) side to the surface side of the structural layer, the state A at the point X first gradually changes to the state B at the point Y and gradually changes again. Then, when the state A is reached at the point Z, the distance between the points X and Z becomes a period (0.2 nm or more and 40 nm or less) (in this case, the point Y is located approximately at the midpoint between the points X and Z), and this Such a change in the state A-B-A is repeated in the same cycle. If the period is less than 0.2 nm or exceeds 40 nm, the effect of improving the wear resistance by the modulation structure layer may not be shown. A more preferable range of the period has an upper limit of 35 nm or less, more preferably 30 nm or less, and a lower limit of 0.5 nm or more, more preferably 1 nm or more.

  At least one element selected from the group consisting of Group IVa element, Group Va element, Group VIa element, Al, and Si of the periodic table constituting such a modulation structure layer, and carbon, nitrogen, oxygen, and boron Examples of the compound composed of at least one element selected from the group consisting of include the same compounds as those exemplified in the super multi-layer structure layer.

  Such a modulation structure layer can be formed by a manufacturing method similar to the manufacturing method of the super multi-layer structure layer described above, and particularly in the case of a modulation structure layer having a structure in which the composition ratio changes in the thickness direction. They can be formed by setting targets with different composition ratios in the evaporation source and controlling the number of rotations of the substrate holder.

  In addition, when the composition changes in the thickness direction, there may be no clear difference between the modulation structure layer and the super multi-layer structure layer, but it is not necessary to clearly distinguish such a difference. These do not depart from the scope of the present invention.

<Evaluation of dimensional accuracy>
As a method for verifying the dimensional accuracy of the blade-tip-exchange-type cutting tip, for example, the blade-tip-exchange-type cutting tip may be measured with a measuring instrument such as a general-purpose micrometer, or a non-contact method using a laser. The shape may be measured by Also, prepare a plurality (for example, 100) of cutting edge-exchangeable cutting tips, attach them to a chip holder (for example, a cutting tool for turning applications, a cutter for milling applications), measure the cutting edge position, and then replace the cutting edge. The cutting edge may be removed and the position of the cutting edge measured several times to verify the variation in the cutting edge position, or the blade runout accuracy is measured by attaching multiple cutting edge replacement cutting tips to a cutter that uses multiple chips simultaneously. By repeating this, the blade runout accuracy may be verified as the variation of the blade-tip-exchangeable cutting tip, or any other method may be used.

<Manufacturing method>
The blade-tip-exchangeable cutting tip of the present invention is a conventionally known production except that the outer peripheral portion does not contain free carbon or a processing method for making the free carbon content extremely low as described above. The method can be used without particular limitation.

  For example, after the raw material powder is uniformly mixed, the mixture is press-molded and sintered to obtain a precursor of a blade-tip-exchange-type cutting tip. The cutting edge-exchangeable cutting tip of the present invention can be obtained by executing a simple processing method.

  In addition, various cutting edge treatments such as a honing treatment can be performed on the blade exchangeable cutting tip thus obtained, and the above-described coating can be formed.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these.

<Example 1>
The cutting edge replacement type cutting tip No. 1 made of cemented carbide having a coating on the surface as follows. 1-15 were produced (however, No. 8 and No. 15 did not have a film).

First, a raw material powder blended in a composition composed of 2.0% by mass of TaC, 0.3% by mass of Cr ₃ C ₂ , 11.0% by mass of Co, and WC (remainder) was prepared.

  Subsequently, the raw material powder prepared above and paraffin wax (2.0% by mass with respect to the raw material powder) were charged into a ball mill equipped with an ethanol solvent and a cemented carbide ball, and pulverized for 36 hours. A mixture was obtained by mixing.

  Thereafter, this mixture was spray-dried to obtain a granulated powder. Here, the amount of carbon blended was adjusted so as to obtain the target alloy structure.

  Next, the granulated powder was press-molded and sintered under the following sintering conditions to obtain a blade tip-replaceable cutting tip precursor. Subsequently, an edge (R) having a radius of about 0.05 mm is imparted to the intersection of the rake face and the flank face by performing a SiC brush honing process on the edge edge line of the precursor of the blade edge replaceable cutting tip. Cutting edge processing was performed. Subsequently, a flat polishing process was performed on the bottom surface of the blade-tip-exchange-type cutting tip precursor. As described above, a cutting edge exchangeable cutting tip having a shape of SEMT13T3AGSN-G (manufactured by Sumitomo Electric Hardmetal Co., Ltd.) was produced.

  Subsequently, a coating film was formed under the following film forming conditions on the blade-tip-exchangeable cutting tip thus obtained. Table 1 below shows combinations of sintering conditions and film forming conditions in each cutting edge-exchangeable cutting tip.

<Sintering conditions>
<Sintering condition 1-A>
After heating up to 1200 ° C. at a rate of 5 ° C./min in a vacuum atmosphere of 10 Pa, the temperature is raised to 1400 ° C. at a rate of 5 ° C./min in an Ar atmosphere of 7 kPa and held for 60 minutes. Thereafter, the temperature was lowered to 1340 ° C. at a rate of −5 ° C./min in a 7 kPa Ar atmosphere and held for 10 minutes, and then the furnace was cooled to room temperature in an 80 kPa Ar gas atmosphere.

  The term “cutting-off furnace cooling” refers to a cooling operation in which cooling is performed by cutting off the power supply to the heating part (electric heater) of the sintering furnace.

<Sintering condition 1-B>
After heating up to 1200 ° C. at a rate of 5 ° C./min in a vacuum atmosphere of 10 Pa, the temperature is raised to 1400 ° C. at a rate of 5 ° C./min in an Ar atmosphere of 7 kPa and held for 60 minutes. Thereafter, the temperature was lowered to 1300 ° C. at a rate of −5 ° C./min in an Ar atmosphere of 7 kPa and held for 20 minutes, and then the electric furnace was cooled to room temperature in an Ar gas atmosphere of 80 kPa.

<Sintering condition 1-C>
After heating up to 1200 ° C. at a rate of 5 ° C./min in a vacuum atmosphere of 10 Pa, the temperature is raised to 1400 ° C. at a rate of 5 ° C./min in an Ar atmosphere of 7 kPa and held for 60 minutes. Thereafter, the temperature was lowered to 1280 ° C. at a rate of −5 ° C./min in an Ar atmosphere of 7 kPa and held for 30 minutes, and then the electric furnace was cooled to room temperature in an Ar gas atmosphere of 80 kPa.

<Sintering condition 1-D>
After heating up to 1200 ° C. at a rate of 5 ° C./min in a vacuum atmosphere of 10 Pa, the temperature is raised to 1400 ° C. at a rate of 5 ° C./min in an Ar atmosphere of 7 kPa and held for 60 minutes. Thereafter, the temperature was lowered to 1340 ° C. at a rate of −5 ° C./min in an Ar atmosphere of 7 kPa and held for 60 minutes, and then the furnace was cooled to room temperature in an Ar gas atmosphere of 80 kPa.

  Since this sintering condition is cooled after being held at 1340 ° C. for 60 minutes as compared with the sintering condition 1-A, reduction of free carbon in the outer peripheral portion is promoted.

<Sintering condition 1-E>
After heating up to 1200 ° C. at a rate of 5 ° C./min in a vacuum atmosphere of 10 Pa, the temperature is raised to 1400 ° C. at a rate of 5 ° C./min in an Ar atmosphere of 7 kPa and held for 60 minutes. Thereafter, the temperature was lowered to 1280 ° C. at a rate of −5 ° C./min in an Ar atmosphere of 7 kPa and held for 5 minutes, and then cooled down to room temperature in an Ar gas atmosphere of 80 kPa.

  Since this sintering condition is cooled after being held at 1280 ° C. for 5 minutes as compared with the sintering condition 1-C, the reduction rate of free carbon in the outer peripheral portion is relatively small.

<Sintering condition 1-F>
After heating up to 1200 ° C. at a rate of 5 ° C./min in a vacuum atmosphere of 10 Pa, the temperature is raised to 1400 ° C. at a rate of 5 ° C./min in an Ar atmosphere of 7 kPa and held for 60 minutes. Thereafter, the furnace was cooled down to room temperature in an 80 kPa Ar gas atmosphere.

  Since this sintering condition is cooled after being held at 1400 ° C. for 60 minutes as compared with the sintering condition 1-A, the reduction rate of free carbon in the outer peripheral portion is relatively small.

<Film formation conditions>
<Film formation condition 1-a>
A coating film having a 3 μm super multi-layer structure layer and a 0.5 μm TiSiCN layer was formed on the surface of the cutting edge-exchangeable cutting tip by using a known ion plating method which is a physical vapor deposition method. The super multi-layer structure layer was formed by alternately laminating an AlTiSiN layer having a thickness of 8 nm and a TiSiN layer having a thickness of 6 nm. When the compressive residual stress of the coating film thus formed was measured by the sin ² ψ method using an X-ray stress measuring apparatus, it was confirmed that the absolute value of the compressive residual stress was 0.1 GPa or more.

<Deposition condition 1-b>
A coating film that is a 3 μm thick TiAlN layer was formed on the surface of the blade-tip-exchangeable cutting tip by using a known ion plating method that is a physical vapor deposition method. In the same manner as above, it was confirmed that the absolute value of the compressive residual stress was 0.1 GPa or more.

<Deposition conditions 1-c>
A TiN layer (0.2 μm), an MT-TiCN layer (2.5 μm), and a κ-Al ₂ O ₃ layer (on the surface of the blade-tip-exchangeable cutting tip, using a known vapor phase synthesis method that is a chemical vapor deposition method ( 0.8 μm) and a TiN layer (0.2 μm) were laminated in this order (a numerical value in parentheses indicates a thickness). When the stress was measured in the same manner as described above, it was confirmed that a tensile residual stress having an absolute value of 0.1 GPa or more was applied.

<Evaluation>
<Evaluation of free carbon>
Evaluation of free carbon of the above-prepared blade tip cutting tip was performed as follows.

  First, 50 blade-tip-replaceable cutting tips were prepared, 30 blade-tip-replaceable cutting tips were selected from them, and each blade-tip-replaceable cutting tip was cut and lapped, and then the surface of the blade edge was examined using a metal microscope. In the 0.1 mm width of the part, the structure is observed at a magnification of 100 to 1000 times, and compared with Table 3 of CIS 006C-2007, the thickness and free carbon amount of the outer peripheral part of the cutting edge exchangeable cutting tip, and the core Part of free carbon was identified. For the identification, the average value of the 30 cutting edge-exchangeable cutting tips was used. The results are shown in Table 1.

  In Table 1, those in which the content of free carbon is blank ("-") indicates that no free carbon is contained. Moreover, it shows that the content of free carbon increases in the order of “C02”, “C04”, “C06”, “C08” (the standard is as defined in CIS 006C-2007).

<Dimensional accuracy evaluation>
The dimensional accuracy evaluation of the above-prepared blade tip type cutting tip was performed as follows.

  First, 50 cutting edge-replaceable cutting tips were prepared, and 7 cutting edge-replaceable cutting tips were selected from among them, and they were all of model number WGC4160R (manufactured by Sumitomo Electric Hardmetal Co., Ltd.) having 7 pockets. Attached to the cutter. The pocket for attaching the cutting edge exchangeable cutting tip to the cutter is designated as No. 1-No. No. 7 is determined. No. 1 on the basis of the position (blade height) of the blade-tip-exchangeable cutting tip attached to the pocket 1. 2-No. The difference in height from the position of the blade-tip-exchangeable cutting tip attached to the 7 pocket was defined as the blade runout width, and the maximum value and the average value were calculated.

  The maximum value and average value of the blade runout width of the cutting edge replacement type cutting tip were measured 10 times by the same method as above, and the maximum value of the height difference was shown in the “Maximum” column of “Dimensional Accuracy Evaluation” in Table 1. The average value of the height difference is shown in the “average” column of Table 1. In addition, it shows that the dimensional accuracy of a blade-tip-exchange-type cutting tip is higher as the blade runout width is smaller. By the higher dimensional accuracy, the surface roughness is lowered and the surface gloss of the work material is also improved. In addition, since the load on each cutting edge at the time of cutting becomes uniform, it is difficult for the cutting edge to be lost.

  By the way, the operation of attaching to each of the seven pockets of the cutter using the master tip for inspection with extremely high dimensional accuracy, measuring the position of the blade-tip-exchangeable cutting tip, and then removing it was repeated seven times. The blade runout width calculated by these seven measurements was 2 μm or less. From this, the influence of the blade runout between the cutter pockets can be regarded as 2 μm or less.

  Next, using seven inspection master tips with extremely high dimensional accuracy, each was attached to the seven pockets of the cutter used for dimensional accuracy evaluation, and the position and blade runout width of the blade tip replaceable cutting tip were calculated. The blade runout width was 4 μm or less. From this, when the blade tip replacement type cutting tip having substantially the same size is attached to each of the cutter pockets, the influence of the blade runout of the blade tip replacement type cutting tip can be regarded as 4 μm or less.

<Cutting evaluation-Flank wear amount>
The wear resistance test was carried out by milling steel using the above-obtained blade tip type cutting tip.

  First, one of the cutting edge-exchangeable cutting tips produced above was set on a cutter of model number WGC4160R (manufactured by Sumitomo Electric Hardmetal Co., Ltd.), and a high-speed milling test of steel was performed using this. This performance evaluation is different from the above-described dimensional accuracy evaluation in that only one cutting edge replaceable cutting tip is attached to the cutter instead of seven cutting edge replaceable cutting tips. The cutter was provided with a blade-tip replaceable cutting tip using a screw.

  The conditions for high-speed milling were as follows: SCM435 block material (300 mm × 100 mm) was used as the work material, cutting speed = 270 m / min, feed = 0.30 mm / tooth, depth of cut = 1. Cutting was performed for 10 minutes under the conditions of 5 mm, center cut, cutting oil: water-soluble oil. After cutting in this manner, the flank wear amount (VB) of the cutting edge-exchangeable cutting tip was measured using a comparator. The result is shown in the column of “flank wear amount (mm)” in Table 1. In addition, it has shown that it is excellent in abrasion resistance, so that the amount of flank wear is small.

<Cutting evaluation-Damage rate>
The toughness test was performed by performing intermittent cutting of steel using the cutting edge-exchangeable cutting tip obtained above.

  First, seven of the cutting edge-exchangeable cutting tips produced above were set in seven pockets of a cutter of model number WGC4160R (manufactured by Sumitomo Electric Hardmetal Co., Ltd.), and intermittent cutting of steel was performed using this. This performance evaluation was performed under the condition that the blade runout of the above seven blade-tip-exchangeable cutting tips was within ± 3 μm of the average value of the blade runout.

  The conditions for the intermittent cutting of the steel are as follows: S45C φ10 perforated material block material (300 mm × 100 mm) is used as the work material, cutting speed = 175 m / min, feed = 0.55 mm / tooth The cutting was performed for 1 minute under the conditions of a cutting depth of 2.0 mm, a center cut, and no cutting oil. Intermittent cutting was performed four times under these conditions, and the ratio of the cutting edge replaceable cutting tips out of the total 28 cutting edge replaceable cutting tips was calculated as the failure rate (%). The result is shown in the column of “breakage rate (%)” in Table 1. The lower the breakage rate, the better the cutting edge strength.

<Cutting evaluation-surface roughness Ra / machined surface gloss>
Using the cutting edge-exchangeable cutting tip obtained above, a work surface test of the work material was performed.

  First, seven of the cutting edge-exchangeable cutting tips produced above were set in seven pockets of a cutter of model number WGC4160R (manufactured by Sumitomo Electric Hardmetal Co., Ltd.), and carbon steel was cut using this. This performance evaluation was performed under the condition that the blade runout of the above seven blade-tip-exchangeable cutting tips was within ± 3 μm of the average value of the blade runout. The cutting conditions of the carbon steel were S15C block material (300 mm × 100 mm) as the work material, cutting speed = 160 m / min, feed = 0.27 mm / tooth, cutting depth 1 for this work material. 1 pass was performed under the conditions of 5 mm, center cut, and no cutting oil. The surface roughness (Ra) of the machined surface of the work material cut in this way was measured by the method defined in JIS B 0601-1994, and the result is “Surface roughness Ra (μm)” in Table 1. It is shown in the column. The smaller the value of the surface roughness, the smoother the machined surface, and the better the dimensional accuracy of the cutting edge-exchangeable cutting tip. Further, visual evaluation of the processed surface of the work material processed in this way was performed, and the result is shown in the column “Gloss of processed surface” in Table 1. The closer the gloss is to the mirror surface, the better the dimensional accuracy of the blade-tip-exchangeable cutting tip.

  In Table 1, cutting edge exchange type cutting tip No. 1 to 12 are examples of the present invention. 13 to 15 are comparative examples (the comparative example is marked with “*”).

  As can be seen from Table 1, it was confirmed that the cutting edge-exchangeable cutting tip of the present invention does not contain free carbon in the outer peripheral portion, and thus has both cutting performance and dimensional accuracy. .

<Example 2>
The cutting edge replacement type cutting tip No. 1 made of cemented carbide having a coating on the surface as follows. 1-15 were produced (however, No. 8 and No. 15 did not have a film).

  First, the raw material powder mix | blended with the composition which consists of 7.0 mass% Co and WC (remainder) was prepared.

  Subsequently, the raw material powder prepared above and paraffin wax (2.0% by mass with respect to the raw material powder) were charged into a ball mill equipped with an ethanol solvent and a cemented carbide ball, and pulverized for 36 hours. A mixture was obtained by mixing.

  Thereafter, this mixture was spray-dried to obtain a granulated powder. Here, the amount of carbon blended was adjusted so as to obtain the target alloy structure.

  Next, the granulated powder was press-molded and sintered under the following sintering conditions to obtain a blade tip-replaceable cutting tip precursor. Subsequently, an edge (R) having a radius of about 0.05 mm is imparted to the intersection of the rake face and the flank face by performing a SiC brush honing process on the edge edge line of the precursor of the blade edge replaceable cutting tip. Cutting edge processing was performed. Subsequently, a flat polishing process was performed on the bottom surface of the blade-tip-exchange-type cutting tip precursor. As described above, a blade-tip-exchangeable cutting tip having a shape of SNMT1205ZNEN-G (manufactured by Sumitomo Electric Hardmetal Co., Ltd.) was produced.

  Subsequently, a coating film was formed under the following film forming conditions on the blade-tip-exchangeable cutting tip thus obtained. Table 2 below shows combinations of sintering conditions and film forming conditions in each blade-tip-exchangeable cutting tip.

<Sintering conditions>
<Sintering condition 2-A>
The temperature is raised to 1200 ° C. at a rate of 5 ° C./minute in a vacuum atmosphere of 10 Pa, and then heated to 1450 ° C. at a rate of 5 ° C./minute in an Ar atmosphere of 7 kPa and held for 60 minutes. Thereafter, the temperature was lowered to 1340 ° C. at a rate of −5 ° C./min in a 7 kPa Ar atmosphere and held for 10 minutes, and then the furnace was cooled to room temperature in an 80 kPa Ar gas atmosphere.

<Sintering condition 2-B>
The temperature is raised to 1200 ° C. at a rate of 5 ° C./minute in a vacuum atmosphere of 10 Pa, and then heated to 1450 ° C. at a rate of 5 ° C./minute in an Ar atmosphere of 7 kPa and held for 60 minutes. Thereafter, the temperature was lowered to 1300 ° C. at a rate of −5 ° C./min in an Ar atmosphere of 7 kPa and held for 20 minutes, and then the electric furnace was cooled to room temperature in an Ar gas atmosphere of 80 kPa.

<Sintering condition 2-C>
The temperature is raised to 1200 ° C. at a rate of 5 ° C./minute in a vacuum atmosphere of 10 Pa, and then heated to 1450 ° C. at a rate of 5 ° C./minute in an Ar atmosphere of 7 kPa and held for 60 minutes. Thereafter, the temperature was lowered to 1280 ° C. at a rate of −5 ° C./min in an Ar atmosphere of 7 kPa and held for 30 minutes, and then the electric furnace was cooled to room temperature in an Ar gas atmosphere of 80 kPa.

<Sintering condition 2-D>
The temperature is raised to 1200 ° C. at a rate of 5 ° C./minute in a vacuum atmosphere of 10 Pa, and then heated to 1450 ° C. at a rate of 5 ° C./minute in an Ar atmosphere of 7 kPa and held for 60 minutes. Thereafter, the temperature was lowered to 1340 ° C. at a rate of −5 ° C./min in an Ar atmosphere of 7 kPa and held for 60 minutes, and then the furnace was cooled to room temperature in an Ar gas atmosphere of 80 kPa.

  Since this sintering condition is cooled after being held at 1340 ° C. for 60 minutes as compared with the sintering condition 2-A, reduction of free carbon in the outer peripheral portion is promoted.

<Sintering condition 2-E>
The temperature is raised to 1200 ° C. at a rate of 5 ° C./minute in a vacuum atmosphere of 10 Pa, and then heated to 1450 ° C. at a rate of 5 ° C./minute in an Ar atmosphere of 7 kPa and held for 60 minutes. Thereafter, the temperature was lowered to 1280 ° C. at a rate of −5 ° C./min in an Ar atmosphere of 7 kPa and held for 5 minutes, and then cooled down to room temperature in an Ar gas atmosphere of 80 kPa.

  Since this sintering condition is cooled after being held at 1280 ° C. for 5 minutes as compared with the sintering condition 2-C, the reduction rate of free carbon in the outer peripheral portion is relatively small.

<Sintering condition 2-F>
The temperature is raised to 1200 ° C. at a rate of 5 ° C./minute in a vacuum atmosphere of 10 Pa, and then heated to 1450 ° C. at a rate of 5 ° C./minute in an Ar atmosphere of 7 kPa and held for 60 minutes. Thereafter, the furnace was cooled down to room temperature in an 80 kPa Ar gas atmosphere.

  Since this sintering condition is cooled after being held at 1450 ° C. for 60 minutes as compared with the sintering condition 2-A, the reduction rate of free carbon in the outer peripheral portion is relatively small.

<Film formation conditions>
<Film formation condition 2-a>
A coating film having a 3 μm super multi-layer structure layer and a 0.2 μm TiAlCN layer was formed on the surface of the cutting edge exchange type cutting tip by using a known ion plating method which is a physical vapor deposition method. The super multi-layer structure layer was formed by alternately laminating an AlTiN layer having a thickness of 8 nm and a TiSiN layer having a thickness of 8 nm. When the compressive residual stress of the coating film thus formed was measured by the sin ² ψ method using an X-ray stress measuring apparatus, it was confirmed that the absolute value of the compressive residual stress was 0.1 GPa or more.

<Deposition condition 2-b>
A coating film which is a 3 μm thick TiAlCrN layer was formed on the surface of the cutting edge-exchangeable cutting tip by using a known ion plating method which is a physical vapor deposition method. In the same manner as above, it was confirmed that the absolute value of the compressive residual stress was 0.1 GPa or more.

<Deposition conditions 2-c>
A TiN layer (0.2 μm), an MT-TiCN layer (3.5 μm), and a TiBN layer (0.5 μm) are formed on the surface of the cutting edge-exchangeable cutting tip by using a known vapor phase synthesis method that is a chemical vapor deposition method. A film in which an α-Al ₂ O ₃ layer (2.2 μm) and a TiN layer (0.2 μm) were laminated in this order was formed (the value in parentheses indicates the thickness). When the stress was measured in the same manner as described above, it was confirmed that a tensile residual stress having an absolute value of 0.1 GPa or more was applied.

<Evaluation>
<Evaluation of free carbon>
Evaluation of free carbon of the blade-tip-exchangeable cutting tip produced above was performed in the same manner as in Example 1. The results are shown in Table 2.

<Dimensional accuracy evaluation>
The dimensional accuracy evaluation of the above-prepared blade tip type cutting tip was performed as follows.

  First, 50 blade-tip-exchangeable cutting tips were prepared, each of which eight blade-tip-exchangeable cutting tips were selected, and all of them were model number DNX12125R (manufactured by Sumitomo Electric Hardmetal Co., Ltd.) having eight pockets. Attached to the cutter. The pocket for attaching the cutting edge exchangeable cutting tip to the cutter is designated as No. 1-No. No. 8 is determined. No. 1 on the basis of the position (blade height) of the blade-tip-exchangeable cutting tip attached to the pocket 1. 2-No. The difference in height from the position of the blade-tip-exchangeable cutting tip attached to the eight pockets was taken as the blade runout width, and the maximum value and the average value were calculated.

  The maximum value and average value of the blade runout width of the cutting edge replacement type cutting tip were measured 10 times by the same method as above, and the maximum value of the height difference was shown in the “Maximum” column of “Dimensional accuracy evaluation” in Table 2. The average value of the height difference is shown in the “average” column of Table 2. In addition, it shows that the dimensional accuracy of a blade-tip-exchange-type cutting tip is higher as the blade runout width is smaller. By the higher dimensional accuracy, the surface roughness is lowered and the surface gloss of the work material is also improved. In addition, since the load on each cutting edge at the time of cutting becomes uniform, it is difficult for the cutting edge to be lost.

  By the way, the operation of attaching to each of the eight pockets of the cutter using the inspection master tip with extremely high dimensional accuracy, measuring the position of the cutting edge exchangeable cutting tip, and then removing it was repeated eight times. The blade run width calculated by these eight measurements was 3 μm or less. From this, it can be considered that the influence of the blade runout between the pockets of the cutter is 3 μm or less.

  Next, using eight inspection master tips with extremely high dimensional accuracy, each was attached to eight pockets of a cutter used for dimensional accuracy evaluation, and the position and blade runout width of the blade tip replaceable cutting tip were calculated. The blade run width was 6 μm or less. From this, when the blade tip replacement type cutting tip having substantially the same size is attached to each of the cutter pockets, the influence of the blade runout of the blade tip replacement type cutting tip can be regarded as 6 μm or less.

<Cutting evaluation-Flank wear amount>
The wear resistance test was performed by milling cast iron using the above-obtained blade tip type cutting tip.

  First, one of the cutting edge exchange type cutting tips produced above was set on a cutter of model number DNX12125R (manufactured by Sumitomo Electric Hardmetal Co., Ltd.), and a cast iron milling test was performed using this. This performance evaluation differs from the dimensional accuracy evaluation described above in that only one cutting edge replacement type cutting tip is attached to the cutter instead of eight cutting edge replacement type cutting tips. The cutter was provided with a blade-tip replaceable cutting tip using a screw.

  The milling conditions were as follows: FC250 block material (300 mm x 100 mm) was used as the work material. Cutting speed = 150 m / min, feed = 0.25 mm / blade, depth of cut = 3.0 mm for this work material. Then, cutting was performed for 5 minutes under the conditions of center cutting and cutting oil: none. After cutting in this manner, the flank wear amount (VB) of the cutting edge-exchangeable cutting tip was measured using a comparator. The result is shown in the column of “flank wear amount (mm)” in Table 2. In addition, it has shown that it is excellent in abrasion resistance, so that the amount of flank wear is small.

<Cutting evaluation-Damage rate>
The toughness test was performed by performing intermittent cutting of steel using the cutting edge-exchangeable cutting tip obtained above.

  First, eight of the cutting edge-exchangeable cutting tips produced above were set in eight pockets of a cutter of model number DNX12125R (manufactured by Sumitomo Electric Hardmetal Co., Ltd.), and intermittent cutting of steel was performed using them. This performance evaluation was performed under the condition that the blade runout of the eight blade-tip-exchangeable cutting tips was within ± 3 μm of the average value of the blade runout.

  The condition of the intermittent cutting process of steel is that a block material with SCM435 slit (300 mm × 100 mm) is used as a work material, and cutting speed = 140 m / min, feed = 0.50 mm / blade, incision for this work material. One-pass cutting was performed under the conditions that the amount was 2.0 mm, center cut, and no cutting oil. Intermittent cutting was performed four times under these conditions, and the ratio of the cutting edge-replaceable cutting tips out of the total 32 cutting-edge replacement cutting tips was calculated as the failure rate (%). The results are shown in the column “Damage rate (%)” in Table 2. The lower the breakage rate, the better the cutting edge strength.

<Cutting evaluation-surface roughness Ra / machined surface gloss>
Using the cutting edge-exchangeable cutting tip obtained above, a work surface test of the work material was performed.

  First, eight of the cutting edge-exchangeable cutting tips produced above were set in eight pockets of a cutter of model number DNX12125R (manufactured by Sumitomo Electric Hardmetal Co., Ltd.), and carbon steel was cut using this. This performance evaluation was performed under the condition that the blade runout of the eight blade-tip-exchangeable cutting tips was within ± 3 μm of the average value of the blade runout. The cutting conditions for carbon steel are Scr420H block material (300 mm × 100 mm) as the work material, cutting speed = 180 m / min, feed = 0.26 mm / blade, cutting depth 1 for this work material. 1 pass was performed under the conditions of 5 mm, center cut, and no cutting oil. The surface roughness (Ra) of the machined surface of the work material cut in this way was measured by the method defined in JIS B 0601-1994, and the result is “Surface roughness Ra (μm)” in Table 2. It is shown in the column. The smaller the value of the surface roughness, the smoother the machined surface, and the better the dimensional accuracy of the cutting edge-exchangeable cutting tip. Further, visual evaluation of the processed surface of the work material processed in this way was performed, and the result is shown in the column “Gloss of processed surface” in Table 2. The closer the gloss is to the mirror surface, the better the dimensional accuracy of the blade-tip-exchangeable cutting tip.

  In Table 2, cutting edge exchange type cutting tip No. 1 to 12 are examples of the present invention. 13 to 15 are comparative examples (the comparative example is marked with “*”).

  As is apparent from Table 2, it was confirmed that the cutting edge-exchangeable cutting tip of the present invention does not contain free carbon in the outer peripheral portion, and thus achieves both cutting performance and dimensional accuracy. .

<Example 3>
The blade-tip-exchangeable cutting tip No. made of cermet as follows. 1-14 were produced (however, No. 6-8 has a film on the surface).

First, 2.0 wt% TaC, 2.0 wt% NbC, 7.0 wt% Mo ₂ C, 11.0 wt% WC, 8.0 wt% Co, 8 A raw material powder blended in a composition composed of 0.0 mass% Ni and TiCN (remainder) was prepared.

  Subsequently, the raw material powder prepared above and paraffin wax (3.0% by mass with respect to the raw material powder) were charged into a ball mill equipped with an ethanol solvent and a cemented carbide ball, and pulverized for 72 hours. A mixture was obtained by mixing.

  Thereafter, this mixture was spray-dried to obtain a granulated powder. Here, the amount of carbon blended was adjusted so as to obtain the target alloy structure.

  Next, the granulated powder was press-molded and sintered under the following sintering conditions to obtain a blade tip-replaceable cutting tip precursor. Subsequently, a diamond brush honing process is performed on the edge of the cutting edge precursor of the exchangeable cutting tip, thereby providing a radius (R) having a radius of about 0.08 mm at the intersection of the rake face and the flank face. Cutting edge processing was performed. Subsequently, a flat polishing process was performed on the bottom surface of the blade-tip-exchange-type cutting tip precursor. As described above, a cutting edge exchangeable cutting tip having a shape of SOMT120408PDER-H (manufactured by Sumitomo Electric Hardmetal Co., Ltd.) was produced.

  Subsequently, for the blade-tip-exchangeable cutting tip thus obtained, No. About 6-8, the film was formed on the following film-forming conditions. Table 3 below shows the combinations of the sintering conditions and the film forming conditions in each cutting edge-exchangeable cutting tip.

<Sintering conditions>
<Sintering condition 3-A>
The temperature is raised to 1200 ° C. at a rate of 5 ° C./min in a vacuum atmosphere of 10 Pa, and then heated to 1500 ° C. at a rate of 5 ° C./min in a 1 kPa N ₂ atmosphere and held for 60 minutes. Thereafter, the temperature was lowered to 1340 ° C. at a rate of −5 ° C./min in a 10 Pa vacuum atmosphere and held for 20 minutes, and then the furnace was cooled to room temperature in an 80 kPa Ar gas atmosphere.

<Sintering condition 3-B>
The temperature is raised to 1200 ° C. at a rate of 5 ° C./min in a vacuum atmosphere of 10 Pa, and then heated to 1500 ° C. at a rate of 5 ° C./min in a 1 kPa N ₂ atmosphere and held for 60 minutes. Thereafter, the temperature was lowered to 1300 ° C. at a rate of −5 ° C./min in a vacuum atmosphere of 10 Pa and held for 30 minutes, and then the furnace was cooled to room temperature in an Ar gas atmosphere of 80 kPa.

<Sintering condition 3-C>
The temperature is raised to 1200 ° C. at a rate of 5 ° C./min in a vacuum atmosphere of 10 Pa, and then heated to 1500 ° C. at a rate of 5 ° C./min in a 1 kPa N ₂ atmosphere and held for 60 minutes. Thereafter, the temperature was lowered to 1280 ° C. at a rate of −5 ° C./min in a vacuum atmosphere of 10 Pa and held for 40 minutes, and then the furnace was cooled to room temperature in an Ar gas atmosphere of 80 kPa.

<Sintering condition 3-D>
The temperature is raised to 1200 ° C. at a rate of 5 ° C./min in a vacuum atmosphere of 10 Pa, and then heated to 1500 ° C. at a rate of 5 ° C./min in a 1 kPa N ₂ atmosphere and held for 60 minutes. Thereafter, the temperature was lowered to 1340 ° C. at a rate of −5 ° C./min in a vacuum atmosphere of 10 Pa and maintained for 80 minutes, and then the furnace was cooled to room temperature in an Ar gas atmosphere of 80 kPa.

  Since this sintering condition is cooled after being held at 1340 ° C. for 80 minutes as compared with the sintering condition 3-A, reduction of free carbon in the outer peripheral portion is promoted.

<Sintering condition 3-E>
The temperature is raised to 1200 ° C. at a rate of 5 ° C./min in a vacuum atmosphere of 10 Pa, and then heated to 1500 ° C. at a rate of 5 ° C./min in a 1 kPa N ₂ atmosphere and held for 60 minutes. Thereafter, the temperature was lowered to 1280 ° C. at a rate of −5 ° C./min in a vacuum atmosphere of 10 Pa and held for 10 minutes, and then cooled down to room temperature in an Ar gas atmosphere of 80 kPa.

  Since this sintering condition is cooled after being held at 1280 ° C. for 10 minutes as compared with the sintering condition 3-C, the reduction rate of free carbon in the outer peripheral portion is relatively small.

<Sintering condition 3-F>
The temperature is raised to 1200 ° C. at a rate of 5 ° C./min in a vacuum atmosphere of 10 Pa, and then heated to 1500 ° C. at a rate of 5 ° C./min in a 1 kPa N ₂ atmosphere and held for 60 minutes. Thereafter, the furnace was cooled down to room temperature in an 80 kPa Ar gas atmosphere.

  Since this sintering condition is cooled after being held at 1500 ° C. for 60 minutes as compared with the sintering condition 3-A, the reduction rate of free carbon in the outer peripheral portion is relatively small.

<Film formation conditions>
<Deposition conditions 3-a>
A coating film having a 3 μm super multi-layer structure layer and a 0.5 μm TiSiCN layer was formed on the surface of the cutting edge-exchangeable cutting tip by using a known ion plating method which is a physical vapor deposition method. The super multi-layer structure layer was formed by alternately laminating an AlTiSiN layer having a thickness of 8 nm and a TiSiN layer having a thickness of 6 nm. When the compressive residual stress of the coating film thus formed was measured by the sin ² ψ method using an X-ray stress measuring apparatus, it was confirmed that the absolute value of the compressive residual stress was 0.1 GPa or more.

<Deposition conditions 3-b>
A coating film that is a 3 μm thick TiAlN layer was formed on the surface of the blade-tip-exchangeable cutting tip by using a known ion plating method that is a physical vapor deposition method. In the same manner as above, it was confirmed that the absolute value of the compressive residual stress was 0.1 GPa or more.

<Deposition conditions 3-c>
A TiN layer (0.2 μm), a TiCN layer (3.0 μm), and a TiN layer (0.2 μm) are formed on the surface of the cutting edge-exchangeable cutting tip using a known ion plating method that is a physical vapor deposition method. Films laminated in order were formed (numbers in parentheses indicate thickness). When the stress was measured in the same manner as described above, it was confirmed that a compressive residual stress having an absolute value of 0.1 GPa or more was applied.

<Evaluation>
<Evaluation of free carbon>
Evaluation of free carbon of the blade-tip-exchangeable cutting tip produced above was performed in the same manner as in Example 1. The results are shown in Table 3.

<Dimensional accuracy evaluation>
Except for using the model number WFXF12100R (manufactured by Sumitomo Electric Hardmetal Co., Ltd.) instead of the model number WGC4160R (manufactured by Sumitomo Electric Hardmetal Co., Ltd.) used in Example 1, the other cutters are all the same as in Example 1. Thus, the dimensional accuracy of the cutting edge-exchangeable cutting tip was evaluated. The results are shown in Table 3.

<Cutting evaluation-Flank wear amount>
The wear resistance test was carried out by milling steel using the above-obtained blade tip type cutting tip.

  First, one of the cutting edge-exchangeable cutting tips produced above was set in a cutter of model number WFXF12100R (manufactured by Sumitomo Electric Hardmetal Co., Ltd.), and a high-speed milling test of steel was performed using this. This performance evaluation is different from the above-described dimensional accuracy evaluation in that only one cutting edge replaceable cutting tip is attached to the cutter instead of seven cutting edge replaceable cutting tips. The cutter was provided with a blade-tip replaceable cutting tip using a screw.

  The conditions of the high-speed milling wear resistance evaluation test were as follows: SCM435 block material (300 mm x 80 mm) was used as the work material, cutting speed = 160 m / min, feed = 0.20 mm / tooth, cutting depth Cutting was performed for 5 minutes under the conditions of amount = 1.0 mm, center cut, cutting oil: none. After cutting in this manner, the flank wear amount (VB) of the cutting edge-exchangeable cutting tip was measured using a comparator. The result is shown in the column of “flank wear amount (mm)” in Table 3. In addition, it has shown that it is excellent in abrasion resistance, so that the amount of flank wear is small.

<Cutting evaluation-Damage rate>
The toughness test was performed by performing intermittent cutting of steel using the cutting edge-exchangeable cutting tip obtained above.

  First, seven of the cutting edge-exchangeable cutting tips produced above were set in seven pockets of a cutter of model number WFXF12100R (manufactured by Sumitomo Electric Hardmetal Co., Ltd.), and intermittent cutting of steel was performed using this. This performance evaluation was performed under the condition that the blade runout of the above seven blade-tip-exchangeable cutting tips was within ± 3 μm of the average value of the blade runout.

  The conditions for the intermittent cutting of steel were S45C φ10 perforated block material (300 mm × 80 mm) as the work material, cutting speed = 160 m / min, feed = 0.25 mm / tooth for this work material. Cutting was performed for 0.5 minutes under the conditions of a cutting depth of 2.0 mm, a center cut, and no cutting oil. Intermittent cutting was performed four times under these conditions, and the ratio of the cutting edge replaceable cutting tips out of the total 28 cutting edge replaceable cutting tips was calculated as the failure rate (%). The results are shown in the column “Damage rate (%)” in Table 3. The lower the breakage rate, the better the cutting edge strength.

<Cutting evaluation-surface roughness Ra / machined surface gloss>
Using the cutting edge-exchangeable cutting tip obtained above, a work surface test of the work material was performed.

  First, seven of the cutting edge-exchangeable cutting tips produced above were set in seven pockets of a cutter of model number WFXF12100R (manufactured by Sumitomo Electric Hardmetal Co., Ltd.), and carbon steel was cut using this. This performance evaluation was performed under the condition that the blade runout of the above seven blade-tip-exchangeable cutting tips was within ± 3 μm of the average value of the blade runout. The cutting conditions of the carbon steel were S15C block material (300 mm × 80 mm) as the work material, cutting speed = 100 m / min, feed = 0.15 mm / tooth, cutting depth 1 for this work material. One pass was performed under the conditions of 0.0 mm, center cut, and no cutting oil. The surface roughness (Ra) of the machined surface of the work material cut in this way was measured by the method defined in JIS B 0601-1994, and the result is “Surface roughness Ra (μm)” in Table 3. It is shown in the column. The smaller the value of the surface roughness, the smoother the machined surface, and the better the dimensional accuracy of the cutting edge-exchangeable cutting tip. Further, visual evaluation of the processed surface of the work material processed in this way was performed, and the result is shown in the column “Gloss of processed surface” in Table 3. The closer the gloss is to the mirror surface, the better the dimensional accuracy of the blade-tip-exchangeable cutting tip.

  In Table 3, cutting edge exchange type cutting tip No. 1 to 12 are examples of the present invention. 13 to 14 are comparative examples (the comparative example is marked with “*”).

  As is apparent from Table 3, it was confirmed that the cutting edge-exchangeable cutting tip of the present invention does not contain free carbon in the outer peripheral portion, and thus achieves both cutting performance and dimensional accuracy. .

<Example 4>
The cutting edge replacement type cutting tip No. 1 made of cemented carbide having a coating on the surface as follows. 1-13 were produced (however, No. 8 and No. 13 did not have a film).

  First, the raw material powder mix | blended with the composition which consists of 1.5 mass% NbC, 6.0 mass% Co, and WC (remainder) was prepared.

  Subsequently, the raw material powder prepared above and paraffin wax (2.0% by mass with respect to the raw material powder) were charged into a ball mill equipped with an ethanol solvent and a cemented carbide ball, and pulverized for 36 hours. A mixture was obtained by mixing.

  Thereafter, this mixture was spray-dried to obtain a granulated powder. Here, the amount of carbon blended was adjusted so as to obtain the target alloy structure.

  Next, the granulated powder is press-molded to obtain a molded body having the shape of model number CNMA120408 defined in JIS B4120-1998. The molded body is sintered under the same sintering conditions as in Example 2 to replace the cutting edge. A die cutting tip was obtained. In addition, Table 4 shows the sintering conditions of each blade-tip-exchange-type cutting tip.

Subsequently, the upper and lower surfaces of the blade-exchangeable cutting tip thus obtained were ground with a diamond grindstone, then subjected to a blade edge treatment by 0.05 mm honing as viewed from the rake face with an SiC brush, and then chemical vapor deposition was performed. The TiN layer (0.2 μm), the MT-TiZrCN layer (7.3 μm), the TiBN layer (1.0 μm), and the α-Al ₂ O ₃ layer (4.1 μm) are formed using a known vapor phase synthesis method. ), A TiC layer (0.1 μm), and a TiN layer (0.3 μm) were formed in this order (the number in parentheses indicates the thickness). When the stress was measured in the same manner as described above, it was confirmed that a tensile residual stress having an absolute value of 0.1 GPa or more was applied.

<Evaluation>
<Evaluation of free carbon>
Evaluation of free carbon of the blade-tip-exchangeable cutting tip produced above was performed in the same manner as in Example 1. The results are shown in Table 4.

<Dimensional accuracy evaluation>
The dimensional accuracy evaluation of the above-prepared blade tip type cutting tip was performed as follows.

  First, 10 cutting edge exchange type cutting tips prepared as described above are prepared (four cutting edges exist for one cutting edge exchange type cutting chip).

  Next, the blade tip replaceable cutting tip prepared above is attached to the turning holder PCLNR2525-43 manufactured by Sumitomo Electric Hardmetal Corporation. Specifically, with respect to each cutting edge replaceable cutting tip, 1) mounting of 40 cutting edges, 2) measurement of cutting edge position using a dial gauge, 3) removal of cutting edges, and maximum and minimum cutting edge position accuracy. The difference from the value (this difference is called the blade edge adjustment width) was measured. Further, the standard deviation of the blade edge position (blade edge adjustment width) was calculated. The smaller the blade edge adjustment width, the better the dimensional accuracy of the blade-tip replaceable cutting tip, and the smaller the standard deviation, the better the dimensional accuracy of the blade-tip replaceable cutting tip. The results are shown in Table 4.

<Cutting evaluation-Flank wear amount>
The wear resistance test was performed by turning carbon steel using the cutting edge-exchangeable cutting tip obtained above.

  First, one of the blade-tip-exchangeable cutting tips produced above was set in a holder of model number PCLNR2525-43 (manufactured by Sumitomo Electric Hardmetal Co., Ltd.), and a turning test of carbon steel was performed using this. In addition, a blade-tip-exchangeable cutting tip was attached to the holder by a lever lock type.

  The conditions of the turning process are as follows. An SCr420Hφ250 round bar (outer diameter turning) is used as a work material. Cutting speed = 180 m / min, feed = 0.30 mm / rev. Cutting was performed for 4 minutes under the conditions of a cutting depth = 2.0 mm and cutting oil: water-soluble oil. After cutting in this manner, the flank wear amount (VB) of the cutting edge-exchangeable cutting tip was measured using a comparator. The results are shown in the column of “flank wear amount (mm)” in Table 4. In addition, it has shown that it is excellent in abrasion resistance, so that the amount of flank wear is small.

<Cutting evaluation-Damage rate>
The toughness test was performed by performing intermittent cutting of steel using the cutting edge-exchangeable cutting tip obtained above.

  First, one of the blade-tip-exchangeable cutting tips produced above was set in a holder of model number PCLNR2525-43 (manufactured by Sumitomo Electric Hardmetal Co., Ltd.), and intermittent cutting of steel was performed using this.

  The conditions for the intermittent cutting of steel were as follows: SCM435φ250, four-grooved round bar was used as the work material. Cutting speed = 100 m / min, feed = 0.45 mm / rev. The cutting was performed for 30 seconds under the conditions of a cutting depth of 2.5 mm and no cutting oil. Under these conditions, intermittent cutting was performed 20 times, and the ratio of cutting edge-replaceable cutting tips that had been damaged by cutting all 20 cutting edges was calculated as the failure rate (%). The results are shown in the column “Damage rate (%)” in Table 4. The lower the breakage rate, the better the cutting edge strength.

  In Table 4, cutting edge exchange type cutting tip No. 1 to 10 are examples of the present invention. 11 to 13 are comparative examples (the comparative example is marked with “*”).

  As is clear from Table 4, it was confirmed that the cutting edge-exchangeable cutting tip of the present invention did not contain free carbon in the outer peripheral portion, and thus achieved both cutting performance and dimensional accuracy. .

  In addition, said No. 2 and No. Prepare 10 blade-tip-replaceable cutting tips, 10 each, and attach to the above holder to adjust the blade position 40 times. (There are 4 corners for each blade-replaceable cutting tip, so a total of 40 corners. It means that the operation was carried out) and the time required for this work was measured. No. 11 cutting edge type cutting tip is No. It took 3 times as long as 2 cutting edge-exchangeable cutting tips. Also from this result, it was confirmed that the dimensional accuracy of the cutting edge replacement type cutting tip of the present invention was excellent.

  Although the embodiments and examples of the present invention have been described as described above, it is also planned from the beginning to appropriately combine the configurations of the above-described embodiments and examples.

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

Claims (15)

A cutting edge exchangeable cutting tip made of cemented carbide or cermet,
The cutting edge replacement type cutting tip is composed of two regions, an outer peripheral portion located on the surface side and a core portion located on the inner side from the outer peripheral portion,
The outer peripheral part has a thickness of 2 μm or more and 5 μm or less , and the free carbon content is lower than the free carbon content contained in the core part. The outer peripheral portion is a region where free carbon is less than C02 defined in CIS 006C-2007, which is a porosity classification standard for super hard alloys,
The cutting edge replacement type cutting tip according to claim 1, wherein the core portion is a region where free carbon becomes C02 or more.   The cutting edge replacement type cutting tip according to claim 1, wherein the outer peripheral portion does not contain free carbon. The cemented carbide is
i) tungsten carbide;
ii) at least one element selected from the group consisting of group IVa elements, group Va elements and group VIa elements of the periodic table; and at least one element selected from the group consisting of carbon, nitrogen, oxygen and boron; A compound phase or solid solution phase composed of one or more compounds composed of: iii) a binder phase composed of one or more iron group elements;
iv) consists of inevitable impurities,
The compound phase or solid solution phase is included in the range of 0.1 to 50% by mass,
The blade edge-exchangeable cutting tip according to any one of claims 1 to 3, wherein the binder phase is included in a range of 3 to 30% by mass. The cemented carbide is
i) tungsten carbide;
ii) a binder phase composed of one or more iron group elements;
iii) consists of inevitable impurities,
The blade edge-exchangeable cutting tip according to any one of claims 1 to 3, wherein the binder phase is included in a range of 1 to 30% by mass. The cermet is
i) at least one element selected from the group consisting of group IVa elements, group Va elements and group VIa elements of the periodic table, and at least one element selected from the group consisting of carbon, nitrogen, oxygen and boron; A compound phase or a solid solution phase composed of one or more compounds composed of:
ii) a binder phase composed of one or more iron group elements;
iii) consists of inevitable impurities,
The compound phase or solid solution phase is contained in the range of 70 to 97% by mass,
The blade edge-exchangeable cutting tip according to any one of claims 1 to 3, wherein the binder phase is included in a range of 3 to 30% by mass.   The cutting edge replacement type cutting tip according to any one of claims 1 to 6, wherein a surface portion of the cutting edge replacement type cutting tip is an unground surface.   The blade edge replaceable cutting tip according to any one of claims 1 to 7, wherein the blade edge replaceable cutting tip has a coating film on a surface thereof.   The coating is composed of at least one element selected from the group consisting of group IVa element, group Va element, group VIa element, Al, and Si in the periodic table, or the element, and carbon, nitrogen, oxygen, and boron. The blade-tip-exchangeable cutting tip according to claim 8, comprising one or more layers composed of a compound with at least one element selected from the group. The coating includes a super multi-layer structure layer or a modulation structure layer,
The super multi-layer structure layer includes at least one element selected from the group consisting of group IVa elements, group Va elements, group VIa elements, Al, and Si in the periodic table, and carbon, nitrogen, oxygen, and boron. Two or more types of unit layers composed of a compound composed of at least one element selected from the group have a structure in which each layer is periodically and repeatedly laminated with a thickness of 0.2 nm or more and 20 nm or less,
The modulation structure layer includes at least one element selected from the group consisting of group IVa element, group Va element, group VIa element, Al, and Si in the periodic table, and a group consisting of carbon, nitrogen, oxygen, and boron. The structure according to claim 8 or 9, comprising a compound comprising at least one element selected from the above, wherein the composition or composition ratio of the compound changes in a cycle of 0.2 nm to 40 nm in the thickness direction. The cutting edge replaceable cutting tip as described.   The cutting edge replacement type cutting tip according to any one of claims 8 to 10, wherein the coating is provided with a compressive residual stress of 0.1 GPa or more.   The blade-tip-exchangeable cutting tip according to any one of claims 1 to 11, wherein the blade-tip-exchangeable cutting tip is used for milling.   The blade-tip-exchangeable cutting tip according to any one of claims 1 to 12, wherein the blade-tip-exchangeable cutting tip performs cutting using two or more at the same time.   The cutting edge replacement type cutting tip according to any one of claims 1 to 13, wherein the cutting edge replacement type cutting tip is a positive type.   The blade edge replaceable cutting tip according to any one of claims 1 to 14, wherein the blade edge replaceable cutting tip is formed with a through hole for mounting to a holder with a screw.