JP4878808B2 - Replaceable cutting edge - Google Patents

Description

  The present invention relates to a blade-tip-exchangeable cutting tip (sometimes referred to as a throw-away tip).

  2. Description of the Related Art Conventionally, there is known a blade-tip-exchangeable cutting tip that is detachably attached to a tool and cuts a work material. Many blade-replaceable cutting tips have been proposed in which a hard coating such as ceramic is formed on a substrate made of cemented carbide or cermet for the purpose of improving wear resistance and toughness. Yes.

  And in the blade-tip-exchange-type cutting tip having such a configuration, an attempt to improve various characteristics by changing the composition of the hard coating or changing the thickness of the hard coating between the flank and the rake face. There are various methods (Patent Documents 1 to 4).

  Further, an attempt has been made to form a layer having a color different from that of the lower layer as the outermost layer of the hard coating as described above, and to determine the usage state of the blade-tip-exchangeable cutting tip based on the discolored state of the outermost layer. (Patent Document 5).

However, as demands for high-efficiency cutting such as high-speed cutting are increasing as in recent years, the cutting edge-exchangeable cutting tip that achieves both high wear resistance and toughness required for such high-efficiency cutting It has not been developed yet.
JP 2001-347403 A JP 2004-122263 A JP 2004-122264 A JP 2004-216488 A JP 2002-144108 A

  The present invention has been made in view of the above-described situation, and an object of the present invention is to provide a blade-tip-exchangeable cutting tip that achieves both high wear resistance and high toughness. In particular, the object is to provide a cutting edge-replaceable cutting tip that is effective for high-speed cutting of steel that requires high wear resistance (crater wear resistance) on the rake face side as the chip temperature of the work material increases. And

  In order to solve the above-mentioned problems, the present inventor earnestly studied the contact state between the cutting edge-exchangeable cutting tip and the work material during cutting. As shown in FIG. In the cutting situation in which the peripheral portion of the cutting edge ridge line 4 is in contact with the work material 5 and the flank 3 faces the work material 5 while the rake face 2 is positioned on the chip 6 side, the thickness of the coating layer is Obviously, the thinner the film, the more advantageous it is to improve toughness, and vice versa, in order to improve wear resistance, it is necessary to increase the thickness of the coating layer. As a result of further research, it has been clarified that the former characteristic is particularly remarkable in terms of flank, and the latter characteristic is remarkable in terms of rake. The present invention has finally been completed by further research based on these findings.

  That is, the present invention is a blade-tip-exchangeable cutting tip having a base material and a coating layer formed on the base material, wherein the base material has at least one flank and at least one rake face. The flank and the rake face are connected to each other with a cutting edge ridge line interposed therebetween, and the coating layer includes an inner layer composed of one or more layers and an outer layer formed on the inner layer. Composed of at least one metal selected from the group consisting of group IVa element, group Va element, group VIa element, Al and Si in the periodic table, or at least one of the above metals and carbon, nitrogen, oxygen and The outer layer is composed of a compound formed of at least one element selected from the group consisting of boron, and the outer layer has an average thickness on the flank side of A μm and the rake at a portion involved in cutting. The average thickness of the side in the case of the Bimyuemu, according to the indexable insert, characterized in that the A / B ≦ 0.9.

Here, the outer layer, at a site involved in cutting, the surface roughness R _a in the flank face side Esumyuemu, the surface roughness R _a in the rake face side when the Tμm, S / T ≦ 0. It is preferably 95.

  The present invention also provides a blade-tip-exchangeable cutting tip having a base material and a coating layer formed on the base material, wherein the base material has at least two flank surfaces and at least one rake surface. The flank and the rake face are connected to each other across the edge of the cutting edge, and the corner is an intersection where the two flank faces and the one rake face intersect, The coating layer includes an inner layer composed of one or more layers and an outer layer formed on the inner layer. The outer layer is composed of an IVa group element, a Va group element, a VIa group element, Al, and Si in the periodic table. Or a compound formed by at least one metal selected from the group consisting of at least one metal selected from the group consisting of carbon, nitrogen, oxygen and boron. The angle formed by the two flank faces constituting the corner is divided into two equal parts on the rake face, and the two flank faces intersect from the rake face. On the straight line connected to the ridge, this outer layer has an average thickness of A μm in the line segment area from 0.5 mm to 1 mm from the corner to the flank side, and from 0.5 mm to 1 mm from the corner to the rake face side. The present invention relates to a blade-tip-exchangeable cutting tip characterized in that A / B ≦ 0.9 when an average thickness in a line segment area as follows is B μm.

On the straight line, the outer layer has a surface roughness Ra in _a line segment area of 0.5 mm or more and 1 mm or less from the corner to the flank side, and 0.5 μm or more to 1 mm from the corner to the rake face side. the surface roughness R _a in the line section to be less when the Timyuemu, it is preferable that the S / T ≦ 0.95.

  The present invention is also a blade-tip-exchangeable cutting tip having a base material and a coating layer formed on the base material, wherein the base material has at least one flank and at least one rake face. The flank and the rake face are connected to each other with a cutting edge ridge line interposed therebetween, and the coating layer includes an inner layer composed of one or more layers and an outer layer formed on the inner layer. Composed of at least one metal selected from the group consisting of group IVa element, group Va element, group VIa element, Al and Si in the periodic table, or at least one of the above metals and carbon, nitrogen, oxygen and A region formed by a compound formed by at least one element selected from the group consisting of boron, the inner layer having a distance of less than 0.4 mm from the cutting edge ridge to the flank side; and Above edge To the rake face side with a distance of less than 2 mm, and the surface of the inner layer in the exposed portion is composed of an alumina layer or a layer containing alumina, and the outer layer is formed of the inner layer. The average thickness in the region having a width of 0.2 mm and extending from a point 0.4 mm away from the exposed portion in the center direction of the flank is A μm, and the average thickness of the inner layer from the exposed portion is set to 0. The present invention relates to a blade-tip-exchangeable cutting tip characterized in that A / B ≦ 0.9 when the average thickness in a region that has a width of 0.2 mm and spreads from a point that is 4 mm apart is B μm.

The outer layer has a surface roughness _Ra of S μm in a region having a width of 0.2 mm further than a point 0.4 mm away from the exposed portion of the inner layer in the center direction of the flank, and the inner layer is exposed. S / T ≦ 0.95 when the surface roughness _Ra is T μm in a region having a width of 0.2 mm further from the point 0.4 mm away from the point in the center direction of the rake face. It is preferable.

  The base material can be composed of any one of cemented carbide, cermet, high speed steel, ceramics, cubic boron nitride sintered body, diamond sintered body, or silicon nitride sintered body.

  In addition, the above-mentioned cutting edge exchange type cutting tip is used for drilling, end milling, milling, turning, metal saw processing, gear cutting tool processing, reamer processing, tap processing, or crankshaft pin milling. It can be any one for processing.

  Since the cutting edge-exchangeable cutting tip of the present invention has the configuration as described above, it has succeeded in achieving both high wear resistance and toughness. It shows extremely effective performance for high-speed cutting of steel that requires higher wear resistance (crater wear resistance) on the rake face side.

  Hereinafter, the present invention will be described in more detail. In the following description of the embodiments, the description is made with reference to the drawings. In the drawings of the present application, the same reference numerals denote the same or corresponding parts. Each drawing is merely a schematic diagram for explanation, and the film thickness ratio of the coating layer to the base material and the corner (R) size ratio are different from the actual ones.

<Cutting edge type cutting tip>
The cutting edge-exchangeable cutting tip of the present invention has a base material and a coating layer formed on the base material. The cutting edge-replaceable cutting tip of the present invention includes drilling, end milling, milling, turning, metal saw processing, cutting tool processing, reamer processing, tapping and crankshaft pins. It is particularly useful for milling.

  The present invention is effective for either a negative-type or a positive-type blade-tip-exchangeable cutting tip, and for both a chip breaker formed and a chip breaker not formed. It is valid.

<Base material>
As a material constituting the base material of the present invention, a conventionally known material known as a base material for such a blade-tip-exchange-type cutting tip can be used without particular limitation. For example, a cemented carbide (for example, a WC-based cemented carbide). Alloy, WC, Co, or Ti, Ta, Nb and other carbides, nitrides, carbonitrides, etc.), cermet (TiC, TiN, TiCN, etc.) ), High speed steel, ceramics (such as titanium carbide, silicon carbide, silicon nitride, aluminum nitride, aluminum oxide, and mixtures thereof), cubic boron nitride sintered body, diamond sintered body, or silicon nitride sintered body The body etc. can be mentioned.

  In addition, these substrates may be those whose surfaces are modified. For example, in the case of cemented carbide, a de-β layer may be formed on the surface, or in the case of cermet, a surface hardened layer may be formed, and even if the surface is modified in this way, The effect is shown.

  Moreover, the shape of a base material can employ | adopt without limitation especially the conventionally well-known thing known as a base material shape of such a blade-tip-exchange-type cutting tip. For example, when expressed in a cross-sectional shape parallel to the surface of the base material, a shape such as a rhombus, a square, a triangle, a circle, and an ellipse is included.

  And such a base material 8 is provided with the structure which has at least 1 flank 3 and at least 1 rake face 2 as shown, for example in FIG. 2, This flank 3 and rake face 2 and Are connected to each other with the cutting edge ridge line 4 interposed therebetween, and the cutting edge ridge line 4 becomes a central action point of the cutting action on the work material. More preferably, such a substrate 8 comprises a structure having at least two flank surfaces 3, at least one rake surface 2 and at least one corner 9, the corner 9 having two It is an intersection where the flank 3 and one rake face 2 intersect, and is often the most central action point of the cutting action.

  In addition, expressions such as flank, rake face, cutting edge ridge line and corner used in the present application are not only the surface portion of the base material but also the portion and surface located on the outermost surface portion of the cutting edge replaceable cutting tip 1, It is a concept that includes the corresponding portions located on the surface and inside of each layer such as the outer layer.

  Further, the edge edge 4 of the cutting edge is formed in a straight line shape in FIG. 2, but is not limited to this. For example, a circumferential shape, a wavy shape, a curved shape, or a refractive shape may be used. included. In addition, such a blade edge ridge line or corner can be subjected to a blade edge processing such as chamfering and / or a corner (R) imparting process. When a clear edge is no longer formed or a corner no longer forms a clear intersection, it is assumed that the edge processing is not performed on the rake and flank surfaces that have been subjected to such edge processing. Then, by extending each surface geometrically, the ridge or intersection where both surfaces intersect is determined as a hypothetical ridge or intersection, and the hypothetical determined ridge is defined as the edge of the blade edge. Assume that the intersection is the corner. It should be noted that the expressions that the rake face and the flank face are connected to each other with the edge of the cutting edge and the expression of having the edge of the cutting edge include both cases where the cutting edge processing is applied to the cutting edge ridge line. In addition, the expression of an intersection where two flank and one rake face intersect and the expression that the intersection becomes a corner include the case where the edge processing as described above is applied to the corner. Shall be.

  In FIG. 2, the rake face 2 is shown as a flat face, but the rake face may have another structure, for example, a chip breaker or the like, if necessary. The same applies to flank 3. Further, although the flank 3 is shown as a flat surface in FIG. 2, it may be chamfered (divided into a plurality of surface areas) or may have a different shape or curved surface from the flat surface if necessary. Further, it can be formed in a shape provided with a chip breaker.

  In the base material of the present invention, a through hole 7 used as a fixing hole for attaching the cutting edge-replaceable cutting tip 1 to the tool may be formed so as to penetrate the upper surface and the bottom surface. If necessary, another fixing means can be provided in addition to or instead of the fixing hole.

<Coating layer>
The covering layer 11 of the present invention is formed on the base material 8 as shown in FIGS. 3 to 10, for example, and includes an inner layer 12 composed of one or more layers (in the drawing, for convenience, one layer). And the outer layer 13 formed on the inner layer 12 thereof. Hereinafter, the inner layer 12 and the outer layer 13 will be described separately.

  3 and 4 are schematic cross-sectional views schematically showing a cross section of the blade type replaceable cutting tip 1 of the negative type (the rake face 2 and the flank 3 intersect at an angle of 90 ° or more). FIG. 3 does not have a chip breaker, and FIG. 4 has a chip breaker. 5 and 6 are schematic cross-sectional views schematically showing a cross section of a positive type (the rake face 2 and the flank 3 intersect at an acute angle) of the blade-tip-exchangeable cutting tip 1. FIG. Does not have a chip breaker, and FIG. 6 has a chip breaker. 7 to 10 are schematic cross-sectional views schematically showing the state in which the inner layer 12 is exposed on the surface in the vicinity of the edge of the blade edge as described later. is there.

  Moreover, it is preferable that the thickness (overall thickness which consists of an inner layer and an outer layer) of a coating layer is 1 micrometer or more and 32 micrometers or less. In particular, the thickness of the flank is preferably 1 μm or more, more preferably 2 μm or more, further preferably 3 μm or more, and the rake face thickness is 3 μm or more, more preferably 3.5 μm or more, and further preferably 4 μm or more. It is preferable to do. This is because when the flank thickness is less than 1 μm and the rake face thickness is less than 3 μm, the effect of improving various properties such as wear resistance is not sufficiently exhibited. On the other hand, even if the thickness exceeds 32 μm, further improvement in various properties is not recognized, which is not economically advantageous. However, as long as economic efficiency is ignored, the thickness can be 32 μm or more, and the effect of the present invention is shown. As a method for measuring the thickness, for example, a cutting edge-exchangeable cutting tip is cut and the cross section thereof can be measured by observing using a SEM (scanning electron microscope).

<Inner layer>
The inner layer of the present invention is formed as one or more layers between the base material and an outer layer to be described later, and has an effect of improving various characteristics such as wear resistance and toughness of the cutting edge exchangeable cutting tip. Is. Usually, this inner layer preferably has a color different from that of the outer layer described later, and is preferably formed so as to cover the entire surface of the substrate.

  The inner layer preferably has an alumina layer or a layer containing alumina as an uppermost layer in contact with the outer layer described later. By having the alumina layer or the layer containing alumina as the uppermost layer in this way, film damage due to microchipping can be reduced, which contributes to improvement in wear resistance of the entire coating layer.

  Further, such an alumina layer or a layer containing alumina not only has an effect of improving wear resistance but also has a dark color (exactly, it does not exhibit black color itself and is easily affected by the color of the ground. However, in the present application, it may be simply expressed as black), and thus has a merit that a particularly remarkable contrast can be formed with an outer layer to be described later formed thereon. .

The crystal structure of alumina (aluminum oxide, Al ₂ O ₃ ) here is not particularly limited, and α-Al ₂ O ₃ , κ-Al ₂ O ₃ , γ-Al ₂ O _3, or an amorphous state. A state in which Al ₂ O ₃ is contained and these are mixed is also included. Also, including alumina means that at least alumina is included as a part of the layer (if 50% by mass or more is included, it is regarded as including alumina), and the balance is a compound as described later, It can be composed of ZrO ₂ , Y ₂ O ₃ (it can be considered that Zr or Y is added to alumina) or the like, and may contain chlorine, carbon, boron, nitrogen or the like.

  In addition, it is preferable that at least one of the inner layers has a compressive stress, and the alumina layer or the layer containing alumina has a compressive stress in a portion involved in cutting. Is particularly preferred. Thereby, toughness can be improved effectively. In this case, the toughness can be further improved by making the compressive stress of the flank larger than the compressive stress of the rake face, which is preferable.

  Here, as will be described later, the part involved in cutting is a region (described later) having a width of 3 mm from the edge of the cutting edge where the work material comes into contact (closest to the flank side and the rake face side). The region including the line segment areas c and d in FIG. In addition, regarding the definition of this compressive stress, it is assumed that the inner layer is exposed on the surface in this region, and the alumina layer or the layer containing alumina constituting the exposed surface has a compressive stress. Embodiments are included.

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

  Such a compressive stress is preferably a stress having an absolute value of 0.1 GPa or more, more preferably 0.2 GPa or more, and even more preferably 0.5 GPa or more. If the absolute value is less than 0.1 GPa, sufficient toughness may not be obtained. On the other hand, the larger the absolute value, the better from the viewpoint of imparting toughness, but the absolute value exceeds 8 GPa. And the coating layer itself may peel off, which is not preferable.

The residual stress can be measured by the sin ² ψ method using an X-ray stress measuring device. Such residual stress is 10 points included in the area where compressive stress is applied in the inner layer (each point is a distance of 0.1 mm or more from each other so that the stress of the area of the layer can be represented). It is preferable that the stress is preferably selected by separating them from each other, and the stress is measured by the sin ² ψ method, and the average value is obtained.

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 66 of Yokendo) may be used.

  The 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 the residual stress using such Raman spectroscopy is a general one, but for example, described in pages 264 to 271 of “Mechanical characterization technique of thin film” (Sipec, 1992). The method can be adopted.

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

  Such an inner layer can be formed by a known chemical vapor deposition method (CVD method) or physical vapor deposition method (including PVD method, sputtering method, etc.), and the formation method is not limited at all. For example, when the cutting edge-exchangeable cutting tip is used for drilling or end milling, the inner layer is preferably formed by a PVD method that can be formed without reducing the bending strength. In addition, the film thickness of the inner layer is preferably adjusted by the film formation time.

Moreover, when forming an inner layer using well-known CVD method, it is preferable to include the layer formed by MT-CVD (medium temperature CVD) method. In particular, it is optimal to provide a titanium carbonitride (TiCN) layer having excellent wear resistance formed by this method. The conventional CVD method forms a film at about 1020 to 1030 ° C., whereas the MT-CVD method can be performed at a relatively low temperature of about 850 to 950 ° C. Damage can be reduced. Therefore, it is more preferable that the layer formed by the MT-CVD method is provided close to the substrate. Further, it is preferable to use a nitrile gas, particularly acetonitrile (CH ₃ CN), as the gas used in the film formation because of excellent mass productivity. Note that a multilayer structure in which a layer formed by the MT-CVD method as described above and a layer formed by an HT-CVD (high temperature CVD, conventional CVD) method are stacked. As a result, the adhesion between the layers of these coating layers may be improved and may be preferable.

  On the other hand, such an inner layer is formed by laminating one or more layers, and each layer is composed of an IVa group element (Ti, Zr, Hf, etc.), a Va group element (V, Nb, Ta, etc.), Group VIa elements (Cr, Mo, W, etc.), at least one metal selected from the group consisting of Al and Si, and at least one element selected from the group consisting of carbon, nitrogen, oxygen and boron It can be comprised by the compound formed by these. In addition, since the composition ratio (atomic ratio) of these compounds constituting the inner layer can be defined similarly to the composition ratio of the compounds constituting the outer layer described later, details thereof will be described later.

Here, for example, such an inner layer can contain alumina (Al ₂ O ₃ ) as the above-mentioned compound. An example of a specific laminated structure in the case of containing such alumina is as follows. A mode in which a TiN layer is formed, a TiCN layer is formed thereon, and an Al ₂ O ₃ layer is further formed thereon as an uppermost layer can be exemplified. These layers constitute the inner layer as the whole of the three layers, and function as an abrasion resistant layer.

  In addition, as shown in FIGS. 7 to 10, such an inner layer has a region a that spreads from the cutting edge ridge line 4 to the flank 3 side with a distance of less than 0.4 mm (preferably 30 μm or more). , And a region b extending with a distance of less than 2 mm (preferably 100 μm or more) from the cutting edge ridge line 4 to the rake face 2 side, and the surface of the inner layer in the exposed portion is alumina. It is particularly preferable that the layer is composed of a layer or a layer containing alumina. It is considered that welding of the work material occurs remarkably in such regions a and b, and alumina hardly causes a chemical reaction with the components constituting the work material and has low frictional resistance with the work material. Because it becomes. If the distance exceeds the specified value, it is not preferable because the color change as described later of the outer layer formed on the inner layer is not sufficiently shown.

  The distance is preferably less than 0.35 mm, more preferably less than 0.3 mm on the flank side, preferably less than 1.8 mm, more preferably less than 1.5 mm, and even more preferably 0.5 mm on the rake face side. Is less than. The lower limit of the distance is 30 μm or more on the flank 3 side and 100 μm or more on the rake face 2 side. If it is less than this lower limit, the effect of exposing the inner layer may not be sufficiently exhibited, which is not preferable.

  As the method for exposing the inner layer to the surface in this manner, various conventionally known methods can be adopted, and the method is not limited at all. For example, after an outer layer described later is formed on the inner layer, the outer layer is removed by performing blasting, brushing, barrel treatment, or the like on the outer layer at a predetermined portion exposing the inner layer. Can be exposed to the surface.

  In this way, in the vicinity of the edge of the cutting edge, which is the central part for cutting the work material and is highly likely to come into contact with the work material, the surface of the alumina layer or the layer containing alumina is not the outer layer but the inner layer as described later By exposing as the uppermost layer, the welding phenomenon between the coating layer formed on the base material and the work material can be effectively suppressed, thereby effectively deteriorating the surface condition of the work material. In addition to being able to prevent, film damage due to microchipping can be reduced, and the wear resistance of the coating layer can be improved.

As the compound constituting such a inner layer, in addition to the aforementioned alumina _(Al 2 O ₃₎ (with or _Al 2 O ₃₎ as it can be used, for example TiC, TiN, TiCN, TiCNO, TiB 2, TiBN TiBNO, TiCBN, ZrC, ZrO ₂ , HfC, HfN, TiAlN, AlCrN, CrN, VN, TiSiN, TiSiCN, AlTiCrN, TiAlCN, ZrCN, ZrCNO, AlN, AlCN, ZrN, TiAlC, and the like.

  It is particularly preferable to form a layer made of TiBN or TiBNO as the lower layer of the alumina layer or the layer containing alumina. By forming a layer made of such a compound as the lower layer, the adhesion to alumina is greatly improved, and in the part where the alumina is exposed on the surface, the color of such lower layer is recognized through the alumina layer. This is because a color different from the color (black) of alumina in that portion can be provided.

  The thickness of such an inner layer (when formed as two or more layers, the total thickness) is preferably 0.05 μm or more and 30 μm or less. If the thickness is less than 0.05 μm, the effect of improving various properties such as wear resistance is not sufficiently exhibited. Conversely, 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 the thickness, for example, a cutting edge-exchangeable cutting tip is cut and the cross section thereof can be measured by observing using a SEM (scanning electron microscope).

  When the inner layer is exposed on the surface as described above, the boundary between the inner layer and the outer layer is a surface that occupies a unit area (100 μm × 100 μm) by observing the vicinity of the boundary with an electron microscope and / or a metal microscope. It is assumed that the inner layer is exposed on the surface when the area of the inner layer exposed to 80% or more.

<Outer layer>
The outer layer of the present invention is formed as one or more layers on the above inner layer, and includes an IVa group element (Ti, Zr, Hf, etc.), a Va group element (V, Nb, Ta) in the periodic table of elements. Etc.), a group VIa element (Cr, Mo, W, etc.), or at least one metal selected from the group consisting of Al and Si (in the case of being composed of two or more metals, it may be an alloy) Or a compound formed by at least one element selected from the group consisting of carbon, nitrogen, oxygen and boron. The thickness of the outer layer is A / B ≦ 0.9 when the average thickness on the flank side is A μm and the average thickness on the rake face side is B μm at the part involved in cutting. It is a feature.

  In this way, in the part involved in cutting, the thickness of the outer layer is controlled to be thinner on the flank side than on the rake face side as described above, thereby succeeding in dramatically improving toughness while maintaining wear resistance. It is what. In other words, the improvement in wear resistance is achieved by increasing the thickness of the coating layer, but the effect is remarkably exhibited especially on the rake face side, and it is effective to control the thickness of the outer layer having a particularly high hardness. The improvement of toughness can be achieved by reducing the thickness of the coating layer, but the effect is particularly prominent on the flank side, and it is particularly effective to control the thickness of the outer layer with high hardness. Each has been clarified by the inventor's research, and based on this knowledge, further research has been completed to complete the above-described configuration, thereby successfully achieving both high wear resistance and high toughness. Is.

  Here, the part involved in cutting differs depending on the shape of the cutting edge-exchangeable cutting tip, the type and size of the work material, the mode of cutting work, etc., but usually the work material comes into contact (the closest approach) It is assumed that it means an area having a width of 3 mm from the edge of the blade edge to the flank side and the rake face side. In this region, the inner layer is not exposed on the surface (the definition for the thickness of the outer layer when the inner layer is exposed on the surface will be described later).

  In addition, the average thickness A μm on the flank side and the average thickness B μm on the rake face side mean the average values of thicknesses at ten different measurement points in the region. As a method for measuring the thickness, the same measuring method as described above can be employed. For example, the thickness can be measured by cutting a blade-tip-exchangeable cutting tip and observing the cross section using an SEM (scanning electron microscope). can do.

  The A / B value is more preferably A / B ≦ 0.7, and further preferably A / B ≦ 0.5. When the A / B value exceeds 0.9, the effect of achieving both wear resistance and toughness, particularly the effect of improving toughness, is not exhibited. In this respect, even if the A / B value is 1 or less, if it exceeds 0.9, the effect of achieving both wear resistance and toughness is not exhibited. Moreover, it is preferable that the lower limit of A / B value shall be 0.3 or more. This is because if the thickness is less than 0.3, the thickness of the outer layer on the flank side becomes too thin, and color changes as described later are not sufficiently exhibited.

Further, the outer layer is at a site involved in the cutting (i.e. above the region), the surface roughness R _a in the flank face side Esumyuemu, the surface roughness R _a in the rake face side when the Tμm, S / T It is preferable that ≦ 0.95. Thus it is possible to reduce the cutting resistance of the workpiece by a smoother those in the surface roughness R _a of the rake face side than flank side of the outer layer, flank I following side of Although the outer layer is made thinner, the wear resistance can be dramatically improved.

The S / T value is more preferably S / T ≦ 0.9, and more preferably S / T ≦ 0.8. When the S / T value exceeds 0.95, the effect of achieving both wear resistance and toughness (blade edge strength) becomes relatively small. Note that the surface roughness R _a in the present application, is a kind of numerical values representing the surface roughness, and is called a center line average value (JIS B0601: 2001).

  The thickness and surface roughness of the outer layer can be controlled by forming the outer layer once on the inner layer with a uniform thickness and then applying blasting, brushing or barreling to the outer layer. It is preferable to adjust the surface roughness. As a method for controlling the thickness and the surface roughness of the outer layer in this way, a method of directly controlling the outer layer when forming the outer layer, for example, can be adopted as another method. Since it is difficult to form directly as shown in the color, it is particularly effective to adopt a method in which the outer layer is once formed with a uniform thickness and then subjected to blasting, brushing or barreling as described above. is there. When blasting is performed, the slurry can be effectively irradiated from the direction perpendicular to the flank so that the thickness of the outer layer on the flank can be effectively reduced and the surface roughness can be smoothed. preferable. However, a plurality of surfaces can be simultaneously processed by irradiating the slurry from a direction having a predetermined angle with respect to the flank.

  In addition, by performing the treatment as described above, a merit that compressive stress can be applied to at least one of the coating layers, and the strength of the blade edge can be improved is obtained.

  Furthermore, such an outer layer passes through a corner 9 (a hypothetical corner when the cutting edge is processed as shown in the drawing) particularly involved in cutting as shown in FIGS. A straight line L that bisects the angle formed by the two flank faces on the rake face and connects the rake face 2 to the ridge where the two flank faces 3 intersect (in FIG. 11, this straight line L is on the rake face 2). On the ridge where the two flank surfaces intersect (which also leads to a hypothetical ridge if the edge is treated as shown in the drawing) The average thickness in the line segment area c that is 0.5 mm or more and 1 mm or less from the corner 9 to the flank 3 side is A μm, and the average thickness in the line segment area d that is 0.5 mm or more and 1 mm or less from the corner 9 to the rake face 2 side. Bμm If, it is particularly preferable that the A / B ≦ 0.9. By defining in this way, it is possible to more effectively achieve both the wear resistance and the toughness, and in particular, it exhibits extremely effective performance for high-speed cutting of steel.

  Here, the corner involved in cutting includes a corner where the work material actually contacts (closest), and the work material comes into contact with the edge of the edge of the cutting edge in the vicinity of the corner (closest approach). This includes cases involving the cutting (for example, when the temperature rises). However, it does not include a corner where chips of the work material at the time of cutting are scattered and contacted. In the line segment areas c and d, the inner layer is not exposed on the surface (the definition for the thickness of the outer layer when the inner layer is exposed on the surface will be described later).

  In addition, when corners and ridges are treated with cutting edges, the ridge where the two flank surfaces intersect is a hypothetical ridge that is a straight line passing through the middle of the rounded portion connecting the two flank surfaces. And a hypothetical corner (see FIGS. 11 and 12).

  In addition, the line segments c and d are defined as ranges of 0.5 mm or more and 1 mm or less, respectively, as described above, because the chips of the work material that has been cut and heated to an extremely high temperature are within the specified range. This is because there is a high probability of contact with the steel, and it is assumed that this has the greatest influence on properties such as wear resistance and toughness.

  The A / B value is more preferably A / B ≦ 0.7, and further preferably A / B ≦ 0.5. When the A / B value exceeds 0.9, it is impossible to achieve both wear resistance and toughness as described above. In this respect, if the A / B value is 1 or less and exceeds 0.9, it is impossible to achieve both wear resistance and toughness. This is because of the same reason as described above. Conceivable. Moreover, it is preferable that the lower limit of A / B value shall be 0.3 or more. This is because if the thickness is less than 0.3, the thickness of the outer layer on the flank side becomes too thin, and color changes as described later are not sufficiently exhibited.

  The average thicknesses A μm and B μm referred to here mean the average values of the thicknesses at 10 measurement points different from each other in the line segment areas c and d, respectively. The measuring method can be adopted. Further, when a plurality of corners are present in the cutting edge-exchangeable cutting tip, it is necessary to establish the above A / B value relationship for all corners that may be involved in cutting.

Further, the outer layer, Esumyuemu a surface roughness R _a in the line section c of flank 3 side (FIG. 12), the surface roughness R _a in the above line area of the rake face 2 side d (FIG. 12) When T μm, it is preferable that S / T ≦ 0.95. Thus it is possible to reduce the cutting resistance of the workpiece by a smoother those in the surface roughness R _a of the rake face side than flank side of the outer layer, flank I following side of Although the outer layer is made thinner, the wear resistance can be dramatically improved.

  The S / T value is more preferably S / T ≦ 0.9, and more preferably S / T ≦ 0.8. When the S / T value exceeds 0.95, the effect of achieving both wear resistance and toughness (blade edge strength) becomes relatively small.

  Furthermore, as shown in FIG. 14, such an outer layer has the inner layer 12 exposed on the surface in the vicinity of the cutting edge ridge line 4 (that is, a distance of less than 0.4 mm from the cutting edge ridge line 4 to the flank 3 side). The inner layer 12 is exposed on the surface in a region a that extends with a distance of B and a region b that extends with a distance of less than 2 mm from the cutting edge ridge line 4 to the rake face 2 side. (When the surface is composed of an alumina layer or a layer containing alumina) having a width of 0.2 mm further from a point 0.4 mm away from the exposed portion of the inner layer 12 toward the center of the flank 3. The average thickness in the expanded region e is A μm, and the average thickness in the expanded region f having a width of 0.2 mm from the point 0.4 mm away from the exposed portion of the inner layer 12 in the center direction of the rake face 2 is B μm. age In this case, A / B ≦ 0.9. By defining in this way, it is possible to effectively achieve both wear resistance and toughness even when the inner layer is exposed on the surface in the vicinity of the edge of the edge of the cutting edge, and it is extremely effective especially for high-speed cutting of steel. Performance.

  Here, the point 0.4 mm away from the exposed portion of the inner layer 12 in the central direction of the flank 3 is the boundary between the inner layer and the outer layer (the boundary is determined by the method described above) and the edge of the cutting edge ridge line side. Means a point 0.4 mm away in the opposite vertical direction (ie, the vertical direction away from the edge of the blade edge). Similarly, the point 0.4 mm away from the exposed portion of the inner layer 12 in the center direction of the rake face 2 is the horizontal direction opposite to the edge of the blade edge from the boundary between the inner layer and the outer layer (that is, the horizontal direction away from the edge of the blade edge). ) Means a point 0.4 mm away.

  In addition, the above-described regions e and f are defined as regions that have a width of 0.2 mm wider than the point 0.4 mm away from the inner layer exposed portion as described above, in the vicinity of the edge of the blade edge. Thus, when the inner layer is exposed on the surface, it is highly probable that the chips of the work material cut at the exposed portion of the inner layer and heated to an extremely high temperature will come into contact with the region within this specified range. This is because it is presumed to have the greatest influence on properties such as toughness.

  The A / B value is more preferably A / B ≦ 0.7, and further preferably A / B ≦ 0.5. When the A / B value exceeds 0.9, it is impossible to achieve both wear resistance and toughness as described above. In this respect, if the A / B value is 1 or less and exceeds 0.9, it is impossible to achieve both wear resistance and toughness. This is because of the same reason as described above. Conceivable. Moreover, it is preferable that the lower limit of A / B value shall be 0.3 or more. This is because if the thickness is less than 0.3, the thickness of the outer layer on the flank side becomes too thin, and color changes as described later are not sufficiently exhibited.

  The average thicknesses A μm and B μm referred to here mean the average values of the thicknesses at 10 measurement points different from each other in the regions e and f, respectively. The method can be adopted.

Further, the outer layer, Esumyuemu a surface roughness R _a in the flank 3 side of the area e (FIG. 14), when the Tμm the surface roughness R _a in the rake face 2 side of the region f (Fig. 14) Further, it is preferable that S / T ≦ 0.95. Thus it is possible to reduce the cutting resistance of the workpiece by a smoother those in the surface roughness R _a of the rake face side than flank side of the outer layer, flank I following side of Although the outer layer is made thinner, the wear resistance can be dramatically improved.

  The S / T value is more preferably S / T ≦ 0.9, and more preferably S / T ≦ 0.8. When the S / T value exceeds 0.95, the effect of achieving both wear resistance and toughness (blade edge strength) becomes relatively small.

  Such an outer layer can be formed by a known chemical vapor deposition method or a physical vapor deposition method (including a sputtering method), and the formation method is not limited at all.

  The outer layer of the present invention is the outermost layer of the cutting edge replaceable cutting tip except for the case where the inner layer is exposed on the surface as described above, and has the effect of achieving both wear resistance and toughness as described above. More preferably, it exhibits a color different from that of the inner layer (the uppermost layer) (that is, the composition of the inner layer (the uppermost layer) is naturally different), so that the cutting edge replaceable cutting tip (especially the edge of the cutting edge) It also shows a function as a use state display layer for determining the use state. When the edge of the cutting edge is used for cutting a work material, the outer layer formed on the part adjacent to the cutting edge of the edge is worn and the inner layer of the part is exposed on the surface, or the outer layer of the part itself is discolored. Thus, it is possible to identify the edge edge line used by observing the color change.

Such outer layer metal or compound constituting, more specifically there may be mentioned Cr, or Al as for example metal, also TiC as compounds, TiN, TiCN, TiCNO, TiB 2, TiBN, TiBNO, TiCBN, ZrC, ZrO ₂ , HfC, HfN, TiAlN, AlCrN, CrN, VN, TiSiN, TiSiCN, AlTiCrN, TiAlCN, ZrCN, ZrCNO, AlN, AlCN, ZrN, TiAlC and the like. However, Al ₂ O ₃ is not included as such an outer layer. As described above, alumina (Al ₂ O ₃ ) is often formed as the uppermost layer of the inner layer as a single layer or a layer containing the same, and the color itself exhibits a black color, so that it is suitable for use as a use state display layer. This is because there is not.

In the compound constituting the outer layer, the composition ratio (atomic ratio) of at least one of the above metals and at least one element selected from the group consisting of carbon, nitrogen, oxygen and boron is conventionally known. However, it is not necessarily limited to 1: 1, and the latter element can be set to about 0.5 to 1 with respect to the former metal 1 (for example, when Ti _a N _b is used, a + b When b is 100 atomic%, b is about 35 to 50 atomic%). When the latter element is composed of a plurality of elements, the atomic ratio of each element is not necessarily limited to an equal ratio, and a conventionally known atomic ratio can be arbitrarily selected. Therefore, when the compound is represented in the following examples and the like, unless otherwise specified, the atomic ratio constituting the compound can be arbitrarily selected from conventionally known atomic ratios.

  When the outer layer is composed of a plurality of metals (including alloys), the atomic ratio of these metals can be arbitrarily selected from conventionally known atomic ratios.

  Such an outer layer is preferably a layer that changes color when worn. The preferred thickness (the total thickness when two or more outer layers are laminated) is 0.05 μm or more and 2 μm or less, and more preferably 0.1 μm or more and 0.5 μm or less. If it is less than 0.05 μm, it is industrially difficult to uniformly coat a predetermined portion. For this reason, color unevenness may occur in the appearance, and the appearance may be damaged, and the edge of the blade edge is already used. The indication shown is unclear. Moreover, even if it exceeds 2 μm, there is no great difference in the function as a use state display layer, but it is economically disadvantageous. As a method for measuring the thickness, the same measuring method as described above can be employed.

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

<Example 1>
A cemented carbide powder having a composition of 2.0% by mass of TiC, 1.0% by mass of TaC, 1.4% by mass of NbC, 7.8% by mass of Co, and the balance WC is pressed, followed by a vacuum atmosphere. In this case, the cutting tip CNMG120408N is sintered by sintering at 1430 ° C. for 1 hour, and then performing a flat polishing process and a cutting edge treatment with a SiC brush (honing with a width of 0.05 mm as viewed from the rake face side). -A cemented carbide chip having the same shape as that of UX (manufactured by Sumitomo Electric Hardmetal Co., Ltd.) was produced and used as a base material. This base material has a de-β layer formed on the surface of 17 μm, two surfaces are rake surfaces, four surfaces are flank surfaces, and the rake surfaces and flank surfaces are edge edge lines (as described above, the blade edge Since it has been processed, it is a hypothetical ridge). There were a total of eight edge edges. In addition, the intersection of two flank faces and one rake face is a corner (a hypothetical intersection because the cutting edge processing is performed as described above), and there are a total of eight such corners. (However, because of the shape of the chip used here, a corner having an apex angle of 80 ° when observed from the upper surface or the lower surface is often used for cutting purposes. In this case, the number of corners is considered to be four. it can).

On the entire surface of the substrate, the following layers were formed in order from the lower layer as a coating layer by a known thermal CVD method. That is, 0.4 μm TiN, 4.3 μm TiCN (formed by MT-CVD method), and 2.4 μm α-alumina (α-Al ₂ O ₃ ) are formed as inner layers in order from the surface side of the substrate. Then, 1.5 μm of TiN was formed as an outer layer on the α-alumina which is the uppermost layer of these inner layers so as to be in contact therewith (the above coating layer is referred to as coating layer No. 1).

  In the same manner, this coating layer No. In place of the coating layer No. 1 described in Table 1 below. 2-7 were each coat | covered with respect to the whole surface of a base material.

  In Table 1 above, the inner layer was laminated on the surface of the base material in order from the left side. Each layer has a coating layer no. Except for 7 CrN layer, all were formed by known thermal CVD method (those with MT-CVD display were formed by MT-CVD method (film formation temperature 900 ° C.) and those with HT-CVD display were HT-CVD method (formed by a film forming temperature of 1000 ° C.)). The CrN layer was formed by an ion plating method. The outer layer, TiN, is gold, ZrN is platinum, TiCN is pink, and CrN is silver.

  Then, a known blasting method (abrasive material particles: alumina sand No. 120 (average particle size 100 μm), pressure: 0.3 MPa) and / or a brush method (using a diamond brush) is applied to the substrate on which these coating layers are formed. The following five types of treatment methods A to E were carried out using

(Processing method A)
The coating layer was not subjected to any blasting or brushing treatment.

(Processing method B)
The treatment by the brush method was performed so that the thickness of the outer layer was the average thickness described in Tables 2 to 3 with respect to the coating layer.

(Processing method C)
The coating layer was processed by a blast method so that the outer layer had the average thickness shown in Tables 2 to 3.

(Processing method D)
The coating layer was treated by the brush method so that the outer layer had the average thickness described in Tables 2 to 3, and then further treated by the blast method.

(Processing method E)
The coating layer was subjected to a blasting process so that the outer layer had an average thickness described in Tables 2 to 3, and then a brushing process.

  The thickness of the outer layer in Tables 2 to 3 passes through the corners involved in cutting as shown in FIG. 12 (that is, the corner where the following turning cutting test was performed), and the two clearances constituting the corners. A line segment that divides the angle formed by the surface into two equal parts on the rake face, and is 0.5 mm to 1 mm from the corner to the flank face on the straight line connecting the rake face to the ridge where the two flank faces intersect The average thickness in the area c was A μm, the average thickness in the line segment area d that was 0.5 mm to 1 mm from the corner to the rake face side was B μm, and the A / B value was obtained.

  However, in Tables 2 to 3, the thickness of the outer layer for the blade-tip-exchangeable cutting tip described in Table 4 below is the exposed portion of the inner layer (the inner layer exposure distance described in Table 4 is shown in FIG. 14). The average thickness in the region e which has a width of 0.2 mm further from the point 0.4 mm away from the point in the center direction of the flank from the boundary portion between the inner layer and the outer layer as a reference) is A μm, and the exposed portion of the inner layer The A / B value was obtained by setting the average thickness in the region f having a width of 0.2 mm further from the point 0.4 mm away in the center direction of the rake face to B μm.

Further, in Tables 2-3, the surface roughness those described in R _a are each the same segment areas c as the thickness was measured of the outer layer, d or area e, the surface roughness of f R _a As a result, S μm (flank face) and T μm (rake face) were measured to obtain an S / T value.

  In this way, the 32 types of blade-tip-exchangeable cutting tip Nos. Described in Tables 2 to 3 below were used. 1-No. 32 was produced. Those marked with “*” in the table are examples of the present invention, and others are comparative examples.

  In addition, about the blade-tip-exchange-type cutting tip described in Table 4 below, along each blade edge ridgeline, an area a that extends from the edge ridgeline to the flank side with the distance described in Table 4 and the blade edge The inner layer was exposed in the region b which spreads from the ridge line to the rake face side with the distance shown in Table 4. Each distance is a straight line that specifies the boundary between the inner layer and the outer layer with an electron microscope and / or metal microscope as described above, and bisects the angle formed by the two flank faces constituting the corner on the rake face. The rake face distance and the flank face distance on the straight line connecting the rake face to the ridge where the two flank faces intersect were measured.

On the other hand, the above-mentioned blade edge replacement type cutting tip No. 1, no. 2, no. 11, no. 12, no. 16, no. 27 and no. Residual stress was measured for the alumina (α-Al ₂ O ₃ or κ-Al ₂ O ₃ ) layer which is the uppermost layer of the 28 inner layers. This residual stress was measured by measuring a region indicated by a spot U (spot size: 0.5 mm in diameter) in FIG. 15 showing the vicinity of the corner 9 involved in cutting on the flank face side of these cutting edge-replaceable cutting tips. (The specific measurement method employs the sin ² ψ method using the above-described X-ray stress measurement apparatus). In addition, this measurement area | region is an area | region representing the site | part involved in cutting of a flank.

And as a result of this measurement, the residual stress of each blade-tip-exchange-type cutting tip was as follows.
Cutting edge exchange type cutting tip No. 1: 0.2 GPa
Cutting edge exchange type cutting tip No. 2: 0.2 GPa
Cutting edge exchange type cutting tip No. 11: -1.5 GPa
Cutting edge exchange type cutting tip No. 12: -0.4 GPa
Cutting edge exchange type cutting tip No. 16: -0.5 GPa
Cutting edge exchange type cutting tip No. 27: -1.7 GPa
Cutting edge exchange type cutting tip No. 28: -2.4 GPa

  And these cutting edge exchange type cutting tip No. 1 to 32 were subjected to a lathe cutting test under the following conditions, and measured the flank wear amount and the defect rate of the cutting edge replaceable cutting tip (measured the flank wear amount by the wear resistance test and the defect rate by the toughness test). It was measured). The results are shown in Tables 2 to 3 below. In addition, the smaller the flank wear amount, the better the wear resistance, and the smaller the numerical value, the better the toughness.

<Conditions for turning test>
(Abrasion resistance test)
Work material: SCM440 round bar (no interruption)
Cutting speed: 300 m / min.
Feed: 0.3 mm / rev.
Cutting depth: 2.0mm
Cutting oil: Yes (water soluble)
Cutting time: 15 minutes (Toughness test)
Work Material: SCM435 (Round bar with 4 grooves)
Cutting speed: 170 m / min.
Feed: 0.4mm / rev.
Cutting depth: 1.5mm
Cutting oil: Yes (water soluble)
Evaluation: The defect rate is obtained from the number of defects when 20 cutting edges are cut for 2 minutes (that is, the defect ratio (%) = n / 20, where n is the number of defective cutting edges).

As is apparent from Tables 2 to 3, the blade tip replaceable cutting tip of the example of the present invention in which the A / B value obtained from the average thickness A μm and B μm of the outer layer is 0.9 or less is that of the comparative example. The flank wear amount and chipping rate were better than those of the cutting edge-exchangeable cutting tip, and both wear resistance and toughness were highly compatible. Further, this tendency becomes more prominent as the S / T value obtained from the surface roughness R _a S μm, T μm of the outer layer becomes smaller. For reference, the blade tip replaceable cutting tip No. 28 and No. About 32, after removing the outer layer of the whole surface by the blasting method, the same cutting test as described above was performed, and the same result was obtained for the defect rate, but the flank wear amount was inferior and the cutting test was performed. It was difficult to identify the corners used.

  As described above, it is clear that the cutting edge-exchangeable cutting tip according to the embodiment of the present invention has an excellent effect as compared with the cutting edge-exchangeable cutting tip of each comparative example, and has high wear resistance and toughness. It was compatible with both. Furthermore, the cutting edge-exchangeable cutting tip of the example of the present invention can easily identify the corner used for cutting. In addition, although the present Example showed about the case of the blade-tip-exchange-type cutting tip in which the chip breaker was formed, it is effective also for the blade-tip-exchange-type cutting tip in which the chip breaker is not formed as described in the following examples. It is.

<Example 2>
A cemented carbide powder having a composition consisting of 0.6% by mass of TaC, 0.3% by mass of NbC, 5.5% by mass of Co, and the balance of WC is pressed, followed by baking at 1450 ° C. for 1 hour in a vacuum atmosphere. After that, the cutting tip CNMA120408 specified in JIS B4120 (1998 revision) is formed by performing a flat polishing process and a cutting edge processing with a SiC brush (honing 0.05 mm wide as viewed from the rake face side) on the cutting edge ridgeline. A chip made of cemented carbide having the same shape as this was prepared and used as a base material. This base material does not have a chip breaker and has no β-free layer formed on the surface. Two surfaces are rake surfaces, and four surfaces are flank surfaces. The blade edge ridge line (which is a hypothetical ridge because the blade edge processing is performed as described above) is connected. There were a total of eight edge edges. In addition, the intersection of two flank faces and one rake face is a corner (a hypothetical intersection because the cutting edge processing is performed as described above), and there are a total of eight such corners. (However, because of the shape of the chip used here, a corner having an apex angle of 80 ° when observed from the upper surface or the lower surface is often used for cutting purposes. In this case, the number of corners is considered to be four. it can).

  Subsequently, as described in Table 5 below, the same coating layer as in Example 1 was formed on the entire surface of the substrate (that is, the coating layer No. in Table 5 is the coating layer No. in Example 1). .)

And the same 5 types of processing methods AE as Example 1 were each implemented with respect to the base material in which these coating layers were formed. In addition, the thickness, A / B value, surface roughness _Ra and S / T value of the outer layer in Table 5 were determined in the same manner as in Example 1.

  In this way, the 20 kinds of blade-tip-exchangeable cutting tips No. described in Table 5 were used. 33-No. 52 was produced. Those marked with “*” in the table are examples of the present invention, and others are comparative examples. In addition, about the blade-tip-exchange-type cutting tip described in Table 6 below, the inner layer was exposed in the same manner as in Table 4 above.

On the other hand, the above-mentioned blade edge replacement type cutting tip No. 34, no. 37, no. 42, no. 50, no. 51, and no. Residual stress was measured for the alumina (α-Al ₂ O ₃ or κ-Al ₂ O ₃ ) layer, which is the uppermost layer of the inner layer of 52. The measurement of the residual stress was performed by measuring the region indicated by the spot U in FIG. 15 described above (the specific measurement method was the sin ² ψ method using the above-described X-ray stress measurement apparatus). In addition, this measurement area | region is an area | region representing the site | part involved in cutting of a flank.

And as a result of this measurement, the residual stress of each blade-tip-exchange-type cutting tip was as follows.
Cutting edge exchange type cutting tip No. 34: 0.2 GPa
Cutting edge exchange type cutting tip No. 37: 0.2 GPa
Cutting edge exchange type cutting tip No. 42: -0.3 GPa
Cutting edge exchange type cutting tip No. 50: -0.9 GPa
Cutting edge exchange type cutting tip No. 51: -2.0 GPa
Cutting edge exchange type cutting tip No. 52: -2.0 GPa

  And these cutting edge exchange type cutting tip No. About 33-52, the turning cutting test was done on the following conditions, and the flank wear amount and the defect rate of the blade-tip-exchange-type cutting tip were measured. The results are shown in Table 5 below.

<Conditions for turning test>
(Abrasion resistance test)
Work material: Scr420 (Pb-less) square material Cutting speed: 230 m / min.
Feed: 0.4mm / rev.
Cutting depth: 1.0mm
Cutting oil: None Cutting time: 10 minutes (Toughness test)
Work Material: SCM440 (Round bar with 4 grooves)
Cutting speed: 160 m / min.
Feed: 0.36 mm / rev.
Cutting depth: 2.0mm
Cutting oil: Yes (water soluble)
Evaluation: The defect rate is obtained from the number of defects when 20 cutting edges are cut for 2 minutes (that is, the defect ratio (%) = n / 20, where n is the number of defective cutting edges).

As is apparent from Table 5, the blade tip replaceable cutting tip of the embodiment of the present invention having an A / B value of 0.9 or less determined from the average thickness Aμm and Bμm of the outer layer is the blade tip replaceable cutting tip of the comparative example. The flank wear amount and the defect rate were better than those of, and the wear resistance and toughness were highly compatible. Further, this tendency becomes more prominent as the S / T value obtained from the surface roughness R _a S μm, T μm of the outer layer becomes smaller. For reference, the blade tip replaceable cutting tip No. 48 and no. About 51, after removing the outer layer of the whole surface by the blast method, when the same cutting test as the above was performed, the same result was obtained about the defect rate, but the flank wear amount was inferior and the cutting test was performed. It was difficult to identify the corners used.

  As described above, it is clear that the cutting edge-exchangeable cutting tip according to the embodiment of the present invention has an excellent effect as compared with the cutting edge-exchangeable cutting tip of each comparative example, and has high wear resistance and toughness. It was compatible with both. Furthermore, the cutting edge-exchangeable cutting tip of the example of the present invention can easily identify the corner used for cutting.

<Example 3>
A cemented carbide powder having a composition composed of 1.7% by mass of TaC, 10.5% by mass of Co and the balance of WC is pressed, followed by sintering in a vacuum atmosphere at 1390 ° C. for 1 hour, and then a flat polishing process. The cutting edge SEMT13T3AGSN-G (manufactured by Sumitomo Electric Hardmetal Co., Ltd.) has the same shape by performing cutting edge processing with a SiC brush on the cutting edge ridgeline (honing 0.05 mm wide when viewed from the rake face side). A cemented carbide chip having a shape was prepared and used as a base material. This base material does not have a de-β layer on the surface, and one surface is a rake surface, and four surfaces are flank surfaces. The rake surface and the flank surface are edge edges (as described above, the edge processing is performed). It is a hypothetical ridge because it is connected). There were a total of four edge edges. In addition, the intersection where two flank faces and one rake face intersect is a corner (a hypothetical intersection because the cutting edge processing is performed as described above), and there are a total of four such corners. did.

On the entire surface of the substrate, the following layers were formed in order from the lower layer as a coating layer by a known thermal CVD method. Specifically, 0.4 μm TiN, 2.1 μm TiCN (formed by MT-CVD method), and 2.2 μm α-alumina (α-Al ₂ O ₃ ) are formed as inner layers sequentially from the surface side of the substrate. Then, 1.6 μm of TiN was formed as an outer layer on the α-alumina that is the uppermost layer of these inner layers so as to be in contact therewith (the above coating layer is referred to as coating layer No. 8).

  In the same manner, this coating layer No. In place of 8, the coating layer No. described in Table 7 below was used. 9-13 were each coat | covered with respect to the whole surface of a base material.

  In Table 7 above, the inner layer was laminated on the surface of the base material in order from the left side. The coating layer No. 8-10 are coating layer no. As in 7, all were formed by a known thermal CVD method. Coating layer No. 11 to 13 were formed by a known PVD method.

  And the same 5 types of processing methods AE as Example 1 were each implemented with respect to the base material in which these coating layers were formed.

In this way, the 25 types of cutting edge-exchangeable cutting tips No. described in Tables 8 to 9 below were used. 53-No. 77 was produced. Those marked with “*” in the table are examples of the present invention, and others are comparative examples. In addition, the thickness, A / B value, surface roughness _Ra, and S / T value of the outer layer in Tables 8 to 9 were determined in the same manner as in Example 1. Moreover, about the blade-tip-exchange-type cutting tip described in Table 10 below, the inner layer was exposed as in Table 4 of Example 1.

On the other hand, the above-mentioned blade edge replacement type cutting tip No. 53, no. 54, no. 59, no. 61, no. 72 and no. Residual stress was measured for the alumina (α-Al ₂ O ₃ or κ-Al ₂ O ₃ ) layer, which is the uppermost layer of the inner layer of 73. The measurement of the residual stress is performed in the vicinity of the corner 9 involved in cutting on the flank face side of these cutting edge-replaceable cutting tips (the center portion of the part where the cutting edge processing is performed on the ridge where the two flank faces intersect). The area shown by the spot V (spot size: 0.5 mm in diameter) in FIG. 16 was measured (a specific measurement method employs the sin ² ψ method using the above-described X-ray stress measurement apparatus). In addition, this measurement area | region is an area | region representing the site | part involved in cutting of a flank.

And as a result of this measurement, the residual stress of each blade-tip-exchange-type cutting tip was as follows.
Cutting edge exchange type cutting tip No. 53: 0.2 GPa
Cutting edge exchange type cutting tip No. 54: 0.2 GPa
Cutting edge exchange type cutting tip No. 59: -0.3 GPa
Cutting edge exchange type cutting tip No. 61: -0.4 GPa
Cutting edge exchange type cutting tip No. 72: -1.2 GPa
Cutting edge exchange type cutting tip No. 73: -1.2 GPa

  And these cutting edge exchange type cutting tip No. About 53-77, the milling cutting test was done on the following conditions, and the flank wear amount and the defect rate were measured. The results are shown in Table 8 to Table 9 below.

<Conditions for milling cutting test>
(Abrasion resistance test)
Work material: SKD11 block material Cutting speed: 220 m / min.
Feeding: 0.3 mm / blade Cutting depth: 2.0 mm
Cutting oil: Yes (water soluble)
Cutting distance: 2m
Cutter: WGC4160R (manufactured by Sumitomo Electric Hardmetal Corp.)
The number of cutting edge-exchangeable cutting tips attached to the cutter is one (toughness test).
Work material: S50C block material (with slits)
Cutting speed: 150 m / min.
Feed: 0.45mm / blade Cutting depth: 2.0mm
Cutting oil: None Cutting distance: 1m
Cutter: WGC4160R (manufactured by Sumitomo Electric Hardmetal Corp.)
The number of cutting edge-exchangeable cutting tips attached to the cutter was set to one. Evaluation: Defect rate is calculated from the number of defects when cutting 20 cutting edges for 2 minutes (ie, the defect rate when n is the number of defective cutting edges. (%) = N / 20)

As is apparent from Tables 8 to 9, the blade tip replacement type cutting tip of the example of the present invention in which the A / B value obtained from the average thickness A μm and B μm of the outer layer is 0.9 or less is the blade tip replacement of the comparative example. The flank wear amount and defect rate were better than those of the die cutting tip, and both wear resistance and toughness were highly compatible. Further, this tendency becomes more prominent as the S / T value obtained from the surface roughness R _a S μm, T μm of the outer layer becomes smaller. For reference, the blade tip replaceable cutting tip No. 53 and No. About 54, after removing the outer layer of the whole surface by the blasting method, the same cutting test as described above was performed, and the same result was obtained with respect to the defect rate, but the flank wear amount was inferior and the cutting test was performed. It was difficult to identify the corners used.

  As described above, it is clear that the cutting edge-exchangeable cutting tip according to the embodiment of the present invention has an excellent effect as compared with the cutting edge-exchangeable cutting tip of each comparative example, and has high wear resistance and toughness. It was compatible with both. Furthermore, the cutting edge-exchangeable cutting tip of the example of the present invention can easily identify the corner used for cutting. In addition, although the present Example showed about the case of the blade-tip-exchange-type cutting tip in which the chip breaker was formed, it is effective also for the blade-tip-exchange-type cutting tip in which the chip breaker is not formed as described in the following examples. It is.

<Example 4>
A cemented carbide powder having a composition consisting of 0.3% by mass of TaC, 0.3% by mass of Cr ₃ C ₂ , 7.5% by mass of Co and the balance of WC is pressed, followed by 1440 ° C. in a vacuum atmosphere. Sintering was performed for 1 hour, and then a flat polishing process and a blade edge treatment with a SiC brush (0.05 mm width −25 ° honing as seen from the rake face side, see FIG. 13) were applied to the edge of the edge. A chip made of cemented carbide having the same shape as the cutting chip SPGN120408 defined in B4120 (1998 revision) was produced and used as a base material. This substrate does not have a chip breaker and has no β-deposition layer formed on the surface. One surface is a rake surface, four surfaces are flank surfaces, and the rake surfaces and flank surfaces are The blade edge ridge line (which is a hypothetical ridge because the blade edge processing is performed as described above) is connected. There were a total of four edge edges. In addition, the intersection where two flank faces and one rake face intersect is a corner (a hypothetical intersection because the cutting edge processing is performed as described above), and there are a total of four such corners. did.

  Subsequently, as described in Table 11 below, the same coating layer as in Example 3 was formed on the entire surface of the substrate (that is, the coating layer No. in Table 11 is the coating layer No. in Example 3). .)

And the same 5 types of processing methods AE as Example 1 were each implemented with respect to the base material in which these coating layers were formed. The outer layer thickness, A / B value, surface roughness _Ra, and S / T value in Table 11 were obtained in the same manner as in Example 1.

  In this way, the 22 types of cutting edge-exchangeable cutting tips No. 1 listed in Table 11 were used. 78-No. 99 was produced. Those marked with “*” in the table are examples of the present invention, and others are comparative examples. In addition, about the blade-tip-exchange-type cutting tip described in Table 12 below, the inner layer was exposed as in Table 4 of Example 1.

On the other hand, the above-mentioned blade edge replacement type cutting tip No. 80, no. 89, no. 90, no. 91, and no. The residual stress was measured for the uppermost layer (ZrO ₂ layer) of the 92 inner layers. This residual stress was measured by measuring a region indicated by a spot W (spot size: 0.5 mm in diameter) in FIG. 17 showing the vicinity of the corner 9 involved in cutting on the flank face side of these cutting edge-replaceable cutting tips. (The specific measurement method employs the sin ² ψ method using the above-described X-ray stress measurement apparatus). In addition, this measurement area | region is an area | region representing the site | part involved in cutting of a flank.

And as a result of this measurement, the residual stress of each blade-tip-exchange-type cutting tip was as follows.
Cutting edge exchange type cutting tip No. 80: 0.2 GPa
Cutting edge exchange type cutting tip No. 89: -2.3 GPa
Cutting edge exchange type cutting tip No. 90: -0.3 GPa
Cutting edge exchange type cutting tip No. 91: -0.8 GPa
Cutting edge exchange type cutting tip No. 92: -0.9 GPa

  And these cutting edge exchange type cutting tip No. About 78-99, the milling cutting test was done on the following conditions, and the flank wear amount and the defect rate of the blade-tip-exchange-type cutting tip were measured. The results are shown in Table 11 below.

<Conditions for milling cutting test>
(Abrasion resistance test)
Work material: S45C (Pb-less steel)
Cutting speed: 250 m / min.
Feeding: 0.2 mm / blade Cutting depth: 1.0 mm
Cutting oil: None Cutting distance: 5m
Cutter: DPG4160R (manufactured by Sumitomo Electric Hard Metal Co., Ltd.)
The number of cutting edge-exchangeable cutting tips attached to the cutter is one (toughness test).
Work material: SCM435 (with slit)
Cutting speed: 200 m / min.
Feed: 0.35 mm / blade Cutting depth: 2.0 mm
Cutting oil: None Cutting distance: 1m
Cutter: DPG4160R (manufactured by Sumitomo Electric Hard Metal Co., Ltd.)
The number of cutting edge-exchangeable cutting tips attached to the cutter was set to one. Evaluation: Defect rate is calculated from the number of defects when cutting 20 cutting edges for 2 minutes (ie, the defect rate when n is the number of defective cutting edges. (%) = N / 20)

As is clear from Table 11, the cutting edge replaceable cutting tip of the example of the present invention having an A / B value obtained from the average thickness A μm and B μm of the outer layer of 0.9 or less is the cutting edge replaceable cutting tip of the comparative example. The flank wear amount and the defect rate were better than those of, and the wear resistance and toughness were highly compatible. Further, this tendency becomes more prominent as the S / T value obtained from the surface roughness R _a S μm, T μm of the outer layer becomes smaller. For reference, the blade tip replaceable cutting tip No. 89 and No. About 93, after removing the outer layer on the entire surface by the blast method, the same cutting test as described above was performed, but the same result was obtained for the defect rate, but the flank wear amount was inferior and the cutting test was performed. It was difficult to identify the corners used.

  As described above, it is clear that the cutting edge-exchangeable cutting tip according to the embodiment of the present invention has an excellent effect as compared with the cutting edge-exchangeable cutting tip of each comparative example, and has high wear resistance and toughness. It was compatible with both. Furthermore, the cutting edge-exchangeable cutting tip of the example of the present invention can easily identify the corner used for cutting.

  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.

It is the schematic which showed typically the contact state of the blade-tip-exchange-type cutting tip and work material at the time of cutting. It is a schematic perspective view which shows an example of the blade-tip-exchange-type cutting tip of this invention. It is a schematic sectional drawing of the negative type blade-tip-exchange-type cutting tip which does not have a tip breaker. It is a schematic sectional drawing of the negative type blade-tip-exchange-type cutting tip which has a chip breaker. It is a schematic sectional drawing of the positive type blade-tip-exchange-type cutting tip which does not have a tip breaker. It is a schematic sectional drawing of the positive type blade-tip-exchange-type cutting tip which has a chip breaker. It is a schematic sectional drawing of the negative type blade-tip-exchange-type cutting tip which does not have the chip breaker which the inner layer exposed in the blade edge ridgeline vicinity part. It is a schematic sectional drawing of the negative type blade-tip-exchange-type cutting tip which has the chip breaker which the inner layer exposed in the blade edge ridgeline vicinity part. FIG. 3 is a schematic cross-sectional view of a positive type blade edge replacement cutting tip that does not have a chip breaker with an inner layer exposed in the vicinity of the edge of the blade edge. FIG. 3 is a schematic cross-sectional view of a positive type cutting edge exchangeable cutting tip having a chip breaker with an inner layer exposed in the vicinity of the cutting edge ridge line. It is a top view of the blade-tip-exchange-type cutting tip showing the straight line L which bisects the angle which two flank faces make. It is a schematic sectional drawing in the straight line L of FIG. It is the schematic sectional drawing which showed an example of the blade edge | tip process part of a base material. It is a schematic cross-sectional view of the indexable cutting insert showing the average thickness and the surface defined area of roughness R _a in the case where the inner layer is exposed at the edge line vicinity. It is a schematic side view which shows the vicinity of the corner by the side of the flank of a blade-tip-exchange-type cutting tip. It is the schematic which shows the vicinity of the corner by the side of the flank of the blade-tip-exchange-type cutting tip different from FIG. It is a schematic side view which shows the vicinity of the corner of the flank side of the blade-tip-exchange-type cutting tip different from FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Cutting edge exchange type cutting tip, 2 Rake face, 3 Relief face, 4 Edge edge line, 5 Work material, 6 Chip, 7 Through-hole, 8 Base material, 9 Corner, 11 Covering layer, 12 Inner layer, 13 Outer layer.

Claims (4)

A cutting edge-exchangeable cutting tip having a base material and a coating layer formed on the base material,
The substrate has at least one flank and at least one rake face;
The flank and the rake face are connected across a cutting edge ridge line,
The coating layer includes an inner layer composed of one or more layers and an outer layer formed on the inner layer,
The outer layer is composed of at least one metal selected from the group consisting of group IVa elements, group Va elements, group VIa elements, Al and Si in the periodic table, or at least one metal and carbon A compound formed by at least one element selected from the group consisting of nitrogen, oxygen and boron,
The inner layer extends from the cutting edge ridge line to the flank side with a distance of less than 0.4 mm, and the area extends from the cutting edge ridge line to the rake face side with a distance of less than 2 mm. It is exposed and the surface of the inner layer in the exposed part is composed of an alumina layer or a layer containing alumina,
The outer layer has an average thickness Aμm in a region having a width of 0.2 mm further from a point 0.4 mm away from the exposed portion of the inner layer in the center direction of the flank, and from the exposed portion of the inner layer. When the average thickness in the region having a width of 0.2 mm further spread from the point 0.4 mm away from the point of the center of the rake face is B μm, A / B ≦ 0.9,
The blade tip replaceable cutting tip according to claim 1, wherein the inner layer under the outer layer in both regions has the same thickness on the flank side and the rake side. The outer layer has a surface roughness _Ra of S μm in the region having a width of 0.2 mm which is wider than a point 0.4 mm away from the exposed portion of the inner layer in the center direction of the flank, and the inner layer the surface roughness R _a in the region spread has further a width of 0.2mm from a point distant 0.4mm toward the center of the rake face from the exposed portion of the case of the Tμm, S / T ≦
The cutting edge replacement type cutting tip according to claim 1 , wherein the cutting edge exchange type cutting tip is 0.95. The substrate is cemented carbide, cermet, high-speed steel, ceramics, claims characterized in that it is constituted by one of cubic boron nitride sintered body, diamond sintered body or a silicon nitride sintered body, Item 3. The cutting edge replacement type cutting tip according to Item 1 or 2 . The cutting edge exchangeable cutting tip is used for drilling, end milling, milling, turning, metal sawing, gear cutting, reaming, tapping, or crankshaft pin milling The blade-tip-exchangeable cutting tip according to any one of claims 1 to 3 , wherein the cutting tip is a replaceable cutting tip.

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