JP2005281759A - Superhigh pressure sintered structure, superhigh pressure composite sintered structure, production method therefor and cutting tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a superhigh pressure sintered compact having high joining strength with a backing support. <P>SOLUTION: The superhigh pressure sintered structure 1 is obtained by joining a superhigh pressure sintered compact 5 to the surface of a backing support 4 composed of cemented carbide at least comprising cobalt as a joining metal. Regarding the distribution in the concentration of cobalt in the boundary between the backing support 4 and the superhigh pressure sintered compact 5, rapidly changing points are not present, and also, the concentration c of cobalt in each part lies within the concentration ranges of the cobalt concentration C<SB>w</SB>at the inside of the backing support and the cobalt concentration C<SB>h</SB>at the inside of the superhigh pressure composite sintered compact. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ultrahigh-pressure sintered structure or an ultrahigh-pressure composite sintered structure and a method for producing the same, and more particularly to a cutting tool having improved strength and fracture resistance.

  Generally, when producing a diamond or cBN-based ultra-high pressure sintered structure, a diamond or cBN-based structure having a thickness of about 0.5 to 2.0 mm on a backing support made of a WC-Co cemented carbide is used. The raw materials are sintered and bonded by ultra-high pressure firing technology. The tool material (blank) thus obtained is cut into a predetermined shape and brazed onto a cemented carbide base metal as a tool cutting edge portion. At this time, in the conventional method for producing an ultra-high pressure sintered body, cobalt powder or cobalt is used in order to prevent the adhesion between the ultra-high-pressure sintered body and the backing support from being deficient and a decrease in adhesion. A method is known in which a foil is placed, melted and impregnated, and at the same time, an ultra-high pressure raw material (diamond powder) is sintered.

  Further, according to Patent Document 1, only diamond powder is directly placed on the surface of a backing support made of a cemented carbide having a slight undulation, and diamond particles are sintered using cobalt eluted from the cemented carbide as a binder. It is disclosed that this method can reduce the internal residual stress at the interface between the diamond layer and the backing support, improve the adhesion strength of the interface, and prevent the occurrence of cracks between them. Yes.

On the other hand, as in Patent Document 2, an outer periphery of a fibrous core material made of an ultra-high pressure sintered body such as a diamond sintered body is covered with a hard sintered body such as a cemented carbide, and a plurality of ultra-high pressures are focused. It is described that the composite sintered body is used by being bonded to the surface of a cutting edge that is worn, such as a drill bit or a cutter.
JP-A-12-54007 US Pat. No. 6,607,835

  However, in the method in which the cobalt powder described in Patent Document 1 is directly disposed on the surface of the cemented carbide support and fired, cobalt in the cemented carbide is not sufficiently eluted, or conversely Cobalt on the surface side of the alloy was eluted to the ultra-high pressure sintered body side, and a cobalt-deficient region in which the cobalt concentration decreased at the interface was likely to be formed.

  In addition, when placing and firing cobalt powder or cobalt foil between a conventional ultra-high pressure sintered body and a backing support, it is difficult to adjust the amount of cobalt powder or cobalt foil to an optimum amount. After firing, the amount of cobalt in the portion where the cobalt powder or cobalt foil was interposed was deficient, or conversely, cobalt remained in a segregated state due to surplus.

  That is, in any case, the cobalt concentration distribution is non-uniform, and sufficient fracture resistance required when applied to a cutting tool, such as a drill bit or a face mill, that is subjected to high impact can be obtained. There was nothing.

  In addition, Patent Document 2 describes a configuration for bonding an ultra-high pressure composite sintered body to a base surface of a drill bit or a cutter, but does not describe any specific bonding method. When the ultra-high pressure composite sintered body is applied to an excavation tool or a cutting tool, there is a possibility that a defect may occur from the joint portion.

  An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide an ultra-high pressure sintered structure and an ultra-high pressure composite sintered structure with high bonding strength, and a cutting tool using the same.

  As a result of intensive studies to solve the above problems, the present inventor, when joining a super high pressure sintered body to a cemented carbide backing support surface, as a cemented carbide backing support before firing, By using a material having a cobalt-enriched region whose cobalt concentration is higher than that of the inside, and arranging an ultra-high pressure sintered material on the surface of the cobalt-enriched region and firing at an ultra-high pressure, cobalt rich in the backing support Cobalt existing in the activated region is absorbed by diffusing to the side of the ultra high pressure sintered body, that is, the bonding metal necessary for bonding the ultra high pressure sintered body and the backing support is supplemented by diffusion from the backing support. Cobalt powder or cobalt foil is arranged at the interface between the ultra-high pressure sintered body and the backing support without forming a cobalt-deficient region at the boundary between the ultra-high pressure sintered body and the backing support. Firing As in the case of, for example, the occurrence of an inhomogeneous portion of the cobalt concentration that causes a decrease in bonding strength, such as the presence of an abnormal portion where the cobalt concentration rapidly increases locally and the strength decreases, can be prevented as much as possible. As a result, since the difference in thermal expansion coefficient generated between the ultra-high pressure sintered body and the backing support does not change abruptly due to a gradual change in cobalt concentration, the effect of reducing residual stress can be obtained. It has been found that the bonding strength between the bonded body and the backing support can be stably improved, and the ultra-high pressure sintered body becomes difficult to fall off due to poor bonding.

That is, the ultra-high pressure sintered structure of the present invention is obtained by joining an ultra-high pressure sintered body to the surface of a backing support made of a cemented carbide containing at least cobalt as a binding metal, the backing support In the cobalt concentration distribution at the interface between the super-high pressure sintered body and the cobalt concentration c at each location, the cobalt concentration C _w inside the backing support and the cobalt concentration C inside the ultra-high pressure sintered body It exists within the concentration range of _h .

The ultra-high-pressure composite sintered structure of the present invention comprises an ultra-high-pressure composite sintered body obtained by bonding the periphery of a plurality of fibrous core materials made of an ultra-high-pressure sintered body with a hard sintered body. Bonded to the surface of a backing support made of a cemented carbide contained as a binding metal, and in the cobalt concentration distribution at the interface between the backing support and the ultra-high pressure composite sintered body, in which the concentration c is present in the concentration range of concentration C _c of said backing support inside portion of the cobalt concentration C _w and the ultra-high-pressure composite sintered body of the cobalt.

  Here, when the said hard sintered compact consists of a cemented carbide, it is desirable at the point from which the adhesiveness of an ultra-high pressure compound sintered compact and a backing support body is still higher.

  Furthermore, the manufacturing method of the ultra high pressure sintered structure of the present invention includes the metal of the backing support comprising a cemented carbide containing at least cobalt as a binding metal and having a cobalt rich region having a high cobalt concentration on the surface. The ultra-high pressure sintered body material is placed on the enriched region forming surface and fired at a high temperature and an ultra-high pressure.

  The method for producing an ultrahigh-pressure composite sintered structure according to the present invention includes the above-mentioned backing support comprising a cemented carbide containing at least cobalt as a binding metal and having a cobalt-rich region having a high cobalt concentration on the surface. An ultra-high pressure composite molded body in which the periphery of a plurality of fibrous core material molded bodies made of ultra-high pressure sintered body materials is bonded with a hard sintered body raw material molded body is placed on the metal-enriched region forming surface. It is characterized by firing at a high temperature and an ultrahigh pressure.

  Here, in the manufacturing method of the ultra high pressure sintered structure and the ultra high pressure composite sintered structure, the cobalt support Dc inside the backing support and the surface of the backing support for the backing support before firing. The ratio Ds / Dc with respect to the cobalt concentration Ds in is that the amount of cobalt necessary for interfacial adhesive bonding at the boundary portion between the ultrahigh-pressure sintered body or ultrahigh-pressure composite sintered body and the backing support is This is desirable in that it can sufficiently cover the uniformity of cobalt concentration in the sintered body.

  Further, the cutting tool of the present invention is obtained by joining the backing support of the ultra-high pressure sintered structure or the ultra-high pressure composite sintered structure to a predetermined position of a tool base, and A composite sintered body is used as a tool cutting edge, and a long-life cutting tool having excellent fracture resistance and wear resistance can be provided.

  The super-high-pressure sintered structure and the ultra-high-pressure composite sintered structure of the present invention have a cobalt-enriched region in which the cobalt concentration is higher on the surface than the inside when the ultra-high-pressure sintered body is joined to the cemented carbide backing support surface. Is used as a backing support before firing, and an ultra-high pressure sintered raw material is disposed on the surface of the cobalt-enriched region of the backing support and fired at an ultra-high pressure to thereby enrich cobalt in the backing support. Cobalt present in the conversion region is diffused and absorbed by the ultra high pressure sintered body. That is, since the cobalt component necessary for the bonding of the ultra high pressure sintered body and the backing support can be supplemented by diffusion from the backing support, the cobalt deficiency is present at the boundary between the ultra high pressure sintered body and the backing support. Without the formation of the region, as in the case of firing with the cobalt powder and cobalt foil of the ultra-high pressure sintered body and the backing support, the cobalt concentration suddenly changes locally and the strength decreases. It is possible to prevent the inhomogeneous portion of the cobalt concentration that causes a decrease in the bonding strength as much as possible, and the cobalt concentration gradually changes to greatly change the difference in thermal expansion coefficient between the ultra-high pressure sintered body and the backing support. As a result, the effect of reducing the residual stress can also be obtained. As a result, the bonding strength between the ultra-high pressure sintered body and the backing support can be stably improved.

  Hereinafter, an embodiment of an ultrahigh-pressure sintered structure and an ultrahigh-pressure composite sintered structure of the present invention will be described in detail based on the drawings in which this is used for a cutting edge portion of a cutting tool.

  1 and 2 show a cutting tool using the ultra-high pressure sintered structure and the ultra-high pressure composite sintered structure of the present invention for the cutting edge part, respectively, FIGS. 1 and 2 are schematic perspective views, FIG. 2 (b) is a partial sectional view.

  The cutting tools 1 and 21 shown in FIGS. 1 and 2 have a flat plate shape. The mounting seats 3 and 23 formed at the corners of the tool bodies 2 and 22 are provided with backing supports 4 and 24 and an ultra-high pressure sintered body 5. A cutting blade tip comprising an ultra-high pressure sintered structure 6 integrated with the ultra-high-pressure composite sintered body 25 and an ultra-high pressure composite sintered structure 26 is brazed to the tool bodies 2 and 22 with brazing materials 7 and 27. It is attached.

  Moreover, according to this cutting tool 1,21, the cutting blades 10 and 30 are comprised in the intersection ridgeline part of the rake surfaces 8 and 28 and the side flank surfaces 9 and 29. FIG.

  Furthermore, attachment holes 11 and 31 through which a clamp screw or the like for attaching to a tool such as a cutting tool is inserted are formed at the center of the cutting tools 1 and 21.

According to the present invention, the ultra-high pressure sintered structure 6 of FIG. 1 is obtained by joining the ultra-high pressure sintered body 5 to the surface of a backing support 4 made of a cemented carbide containing at least cobalt as a binding metal. Yes, as shown in FIG. 3 (a), the cobalt concentration distribution at the interface between the backing support 4 and the ultra-high pressure sintered body 5 has no sudden change point, and the cobalt concentration c at each location is the backing support. the concentration C _w of cobalt in the body portion being present in a concentration range of concentration C _h cobalt ultrahigh pressure sintered composite body portion.

  As a result, cobalt existing in the cobalt-enriched region 4 in the backing support is diffused and absorbed to the ultrahigh-pressure sintered body 5 side during firing. That is, since the cobalt component necessary for the bonding of the ultrahigh pressure sintered body 5 and the backing support 4 can be supplemented by diffusion from the backing support 5, the boundary portion between the ultrahigh pressure sintered body 5 and the backing support 4. In this case, the cobalt concentration is rapidly increased without the formation of a cobalt-deficient region, and in the case where cobalt powder or cobalt foil is disposed and fired at the interface between the ultrahigh-pressure sintered body 5 and the backing support 4. It is possible to prevent the occurrence of inhomogeneous portions of cobalt concentration, which causes a decrease in bonding strength such as a decrease in strength, in particular, a sudden change in cobalt concentration as much as possible. The difference in thermal expansion coefficient does not change abruptly between the backing support 4 and the backing support 4 so that the effect of preventing the concentration of residual stress can be obtained. As a result, the bonding strength between the ultra-high pressure sintered body 5 and the backing support 4 is increased. Stable improvement Can.

That is, in the hardness distribution of cobalt at the interface between the backing support 4 and the ultra-high pressure sintered body 5, the cobalt concentration is abruptly high as in the case of firing through the cobalt powder or cobalt foil of FIG. If there is a portion, it causes a decrease in strength, and thermal stress concentrates and causes peeling. Further, as shown in FIG. 3B or FIG. 3C, the cobalt concentration c is equal to the cobalt concentration C inside the backing support, as in the case of firing using the backing support having a constant cobalt concentration on the backing support surface. When lower density region than the cobalt concentration C _h a high density area or the ultra-high-pressure sintered composite body section than _w is present, embrittlement or softened area of the strength between the backing support 4 and ultra-high pressure sintered compact 5 , There is a low strength region, and a large residual stress remains between the ultra high pressure sintered body 2 and the backing support 3, so that the ultra high pressure sintered body 5 easily falls off. End up.

  In addition, since the backing support 4 of the present invention supplements cobalt necessary for adhesion to the ultrahigh-pressure sintered body 5 with the metal-enriched region of the backing support 4, the composition of the backing supports 4 and 24 as a whole is It can be formed of a cemented carbide with a low cobalt content. For this reason, when the backing supports 4 and 24 are brazed to the tool bodies 2 and 22, the difference between the cobalt content in the cemented carbide of the tool body and the cobalt content in the backing support becomes small, Since the difference in thermal expansion coefficient that occurs in the case can be reduced, there is an advantage that brazing defects due to thermal stress are less likely to occur.

The inside of the backing support 4 and the ultra high pressure sintered body 5 in the present invention refers to a depth portion separated from the interface between the backing support 4 by 200 μm or more and the ultra high pressure sintered body 5 by 100 μm or more. cobalt concentration c _W in the _region, c _h is defined as the average value of the concentration of cobalt in the band-like region of at least 10μm or wider. The cobalt concentration c at each location is also measured as a mean value by measuring the depth region every 5 μm.

  In addition, the ultra-high-pressure composite sintered body 25 is bonded around the single core of a fibrous core material 51 made of an ultra-high-pressure sintered body as shown in FIG. 4A with a coating layer 52 made of a hard sintered body. For example, a single-core fiber body 53s or a multi-core fiber body 53m in which a plurality of fibrous core materials 51 made of an ultrahigh-pressure sintered body as shown in FIG. 5 (a), the sheets are aligned in one direction and aligned, and the axial direction of the composite fibrous body 53 is arbitrarily set between the sheets as shown in FIGS. 5 (b) and 5 (c). It is also possible to stack by changing the angle (for example, 0 °, 45 °, 90 °, etc.). Further, as shown in FIG. 5D, the composite fiber body 53 may be sliced in the cross-sectional direction.

  Further, as shown in FIG. 5 (a), it may be a single-layer sheet, but the ultrahigh-pressure composite sintered body 16 is a multilayer composite sheet in which a plurality of single-layer sheets are laminated in the thickness direction. Among them, it is desirable in that it has a higher stress dispersion effect. Further, according to the present invention, as shown in FIG. 5 (c), in the multilayer sheet shape, the laminates may be laminated so that the directions of the composite fiber bodies 53, 53 in the adjacent sheets are different. Desirably, this can further enhance the toughness of the ultra-high pressure composite sintered body 16.

According to the present invention, the ultra-high pressure composite sintered structure 26 of FIG. 2 has a cobalt concentration c at each location in the cobalt concentration distribution at the interface between the backing support 24 and the ultra-high pressure composite sintered body 25. present in the concentration range of concentration C _c of cobalt wherein the backing support inside portion of the cobalt concentration C _w ultrahigh pressure sintered composite body portion.

  As a result, the above-described effects are exhibited, and the bonding strength between the ultra-high pressure composite sintered body 25 and the backing support 24 can be stably improved.

  The size of the composite fiber body 53 is such that the core material 51 has a diameter of 5 to 300 μm and includes the covering layer 52 in order to improve the adhesion to the backing support 24 and to improve the fracture resistance as the tool 21. It is desirable that one body 53 has a diameter of 6 to 500 μm.

Furthermore, even if the thermal expansion coefficient alpha ₁ of the core 51 is 3.5~4.8 × ^{10 -6} / ℃, the thermal expansion coefficient alpha ₂ of the coating layer 52 5.0~9 × ^{10 -6} / By setting the temperature to 0 ° C., it is possible to form a good composite structure and cutting tool in which no peeling or the like occurs at the interface between the core material 51 and the coating layer 52.

  The configuration of the tool 21 other than the ultra-high pressure composite sintered structure 26 is the same as that shown in FIG.

  In the present invention, the ultrahigh-pressure sintered body material constituting the ultrahigh-pressure sintered body 5 or the ultrahigh-pressure composite sintered body 25 is an ultrahigh pressure selected from the group of diamond, diamond-like carbon (DLC), or cubic boron nitride (cBN). It consists of an ultra-high pressure material that contains 50% by volume or more of hard particles, is made of cobalt (Co) as an essential component, and is bonded with a bonding metal that contains nickel (Ni) if desired. The ultrahigh pressure material may appropriately contain hard particles composed of one or more of carbides, nitrides, and carbonitrides of the periodic table 4a, 5a, and 6a metals.

  On the other hand, the hard sintered body that forms the coating layer 52 that exists around the core material 51 and joins the core material 51 is a group consisting of carbides, nitrides, and carbonitrides of Group 4a, 5a, and 6a metals. A hard sintered body in which hard particles selected from above are bonded with a bonding metal, or a periodic table 4a, 5a and 6a group metal, an oxide of Al, Si and Zn, carbide, nitride, carbonitride and boride. It is composed of ceramics obtained by bonding ceramic particles selected from the group with a sintering aid.

  Specifically, the material constituting the coating layer 52 is one or more hard particles of periodic table 4a, 5a and 6a group metal carbides, nitrides and carbonitrides, in particular tungsten carbide, titanium carbide, At least one selected from the group consisting of titanium carbonitride, titanium nitride, tantalum carbide, niobium carbide, zirconium carbide, zirconium nitride, vanadium carbide, chromium carbide and molybdenum carbide, and further from the group of tungsten carbide, titanium carbide or titanium carbonitride Hard firing formed by bonding at least one selected from 50 to 97% by volume, in particular tungsten carbide, titanium carbide or titanium carbonitride with cobalt as an essential component and 3 to 50% by volume of a binding metal containing nickel as required. A ligation can be suitably used.

  Here, when the coating layer 52 is made of a cemented carbide, it is desirable in that the adhesion between the ultra-high pressure composite sintered body 25 and the backing support 24 is even higher.

  On the other hand, the backing supports 4 and 24 are made of a WC-based cemented carbide in which a hard phase made of tungsten carbide (WC) is made essential by at least cobalt and bonded by a bonding metal containing nickel if desired.

  Here, the backing supports 4 and 24 have a cobalt-added region on the surface before ultra-high pressure sintering, and in order to obtain such a configuration, a periodic table other than W (tungsten) is included in the cemented carbide. It is desirable to comprise one or more of carbides, nitrides, and carbonitrides of group 4a, 5a, and 6a metals (so-called β metals).

  According to the present invention, the cutting tool may be a solid type tool, but in terms of low cost and ease of manufacture, the throwaway type tools 1 and 21 as shown in FIGS. It is desirable to be.

  1 and 2 exemplify the cutting tool, the present invention is not limited to this, and is applied to other tools such as excavation tools and cutting tools, wear-resistant parts such as sliding parts and dies. Is also possible.

(Production method)
Next, the manufacturing method of the cutting tool of this invention is demonstrated.

  First, in order to produce a cemented carbide backing support of the present invention, an WC powder having an average particle size of 0.1 to 10 μm and an iron group metal powder containing at least cobalt having an average particle size of 0.5 to 10 μm are used. 5 to 20% by volume, and if necessary, a mixed powder to which at least one kind of carbide, nitride, and carbonitride selected from the group of metals of Group 4a, 5a, and 6a other than W is added is prepared. . Here, as the β metal compound raw material, it is desirable to use a nitride or carbonitride in that a metal-enriched region can be reliably formed on the surface.

Next, the mixed powder is formed into a predetermined backing support shape and fired in a temperature range of 1350 to 1600 ° C. for 0.5 to 2 hours. At this time, the firing atmosphere is controlled in accordance with the added amount and presence / absence of added nitride and / or carbonitride. Specifically, when the addition amount of the nitride and / or carbonitride is very small or not added, in addition to the firing conditions, 0 to 2101 kPa N ₂ gas in the temperature range of 1250 to 1350 ° C. By performing the treatment for 2 to 1 h, it is possible to obtain a support in which a metal-enriched region having a high cobalt concentration is formed on the surface layer portion. Furthermore, by changing the amount of cobalt in the cemented carbide, the amount of nitride and / or carbonitride added in the β metal compound raw material, and the mixing ratio of the N ₂ gas component in the atmosphere during firing, the metal-enriched region It is possible to control the ratio D _s / D _c with the thickness and the inner cobalt concentration.

Here, ultra-high pressure sintered body 5 of the backing support 4,24 to cobalt concentration D _c in the interior of the lining support 4,24, the ratio D of the cobalt concentration D _s the extra-high-pressure composite sintered body 25 mounting surface surface _{When s} / _Dc is 1.05 or more, particularly 1.2 or more, the amount of cobalt necessary for interfacial close-bonding with the ultrahigh-pressure sintered body 5 and the ultrahigh-pressure composite sintered body 25 may be sufficiently covered. This is desirable because it can be done.

  Furthermore, when the thickness of the metal-enriched region is 5 μm or more, particularly 20 to 50 μm from the interface between the backing support 4 and the ultrahigh-pressure sintered body 5, sufficient bonding strength with the ultrahigh-pressure sintered body 5 is obtained. Is desirable.

  The cemented carbide backing support 4 is processed into a desired shape, and ultrahigh pressure firing is performed together with the ultrahigh pressure molded body. At this time, the surface of the skin with the metal-enriched region of the backing support is used for the joint surface with the ultra-high pressure sintered body.

  On the other hand, when using an ultra-high pressure sintered body, an ultra-high pressure molded body 40 is produced by mixing and molding raw material powders for producing the ultra-high pressure sintered body.

  On the other hand, a manufacturing method when using the ultra-high pressure composite sintered structure will be described. 6 and 7 are process diagrams for explaining a method of manufacturing the composite fiber body 53 of FIG.

  In producing the composite fiber body 53, first, the core material molded body 51a is produced. The core material molded body 51a can be basically manufactured by a known powder metallurgy method, that is, a method in which raw material powder and a binder (binder) are mixed and molded.

  As a specific method, the case where a diamond sintered body is selected from the above-described core material 51 will be described. First, a diamond powder having an average particle size of 0.01 to 10 μm, particularly 0.1 to 3.5 μm is prepared. 50% by mass or more, in particular 80% by mass or more, and if desired, an iron group metal powder having an average particle size of 0.01 to 10 μm is mixed in a proportion of 50% by mass or less, and further an organic binder, a plasticizer and a solvent are mixed. It is added and kneaded, and formed into a cylindrical shape by a molding method such as press molding or cast molding to produce a core material compact 51a (see FIG. 6A).

  Here, in order to obtain a homogeneous composite molded body by coextrusion molding to be described later, it is desirable that the amount of the organic binder added is 30 to 70 parts by volume, particularly 40 to 60 parts by volume.

  As the organic binder, paraffin wax, polystyrene, polyethylene, ethylene-ethyl acrylate, ethylene-vinyl acetate, polybutyl methacrylate, polyethylene glycol, dibutyl phthalate, or the like can be used.

  On the other hand, two half-cylindrical coating layers are formed by kneading a material having a coating layer having a composition different from that of the core molding 51a together with the above-described binder by a molding method such as press molding, extrusion molding or casting. A molded body 52a is prepared, and a molded body 53a in which the covering layer molded body 52a is arranged so as to cover the outer periphery of the core material molded body 51a is manufactured (see FIGS. 6B and 6C).

  Then, by using the extruder 100 to co-extrusion the molded body 53a composed of the core body molded body 51a and the coating layer molded body 52a, the coated body molded body is formed around the core material molded body 51a. The single-type single-core fiber body 53s of FIG. 4A covered with 52a and extended to a thin diameter can be produced (see FIG. 6D).

  Further, in forming the composite fiber body 53, as shown in FIG. 7, by re-extruding the converging body 54 in which a plurality of the co-extruded long single-core fiber bodies 53s are bundled, FIG. A multi-type multi-core fiber body 53m having a high fiber density as shown in b) can be produced. The cross sections of the composite fiber bodies 53s and 53m may be not only a circle but also a square or a triangle.

  And as shown to Fig.5 (a)-(c), this long composite fiber body 53 is aligned in 2 rows-100 rows, and it heat-presses in a type | mold, and obtained the composite sheet 55, If desired, a plurality of the composite sheets 55 may be laminated in the thickness direction so that the directions of the composite fiber bodies 53 of the adjacent composite sheets 55 and 55 are different from each other. A structural molded body 56 is obtained.

  In addition, the composite structure can be cut in the cross-sectional direction of the composite fiber body 53 as shown in FIG. 5 (d) as needed, or between the pair of rollers 60 as shown in FIG. It is also possible to produce a composite laminate molded body 61 having a higher density by rolling it through.

  Further, the single-layer composite sheet 55, the multilayer composite structure molded body 56 or the composite laminate molded body 61 is placed on the cemented carbide backing support 24 and heated at 300 to 700 ° C. for 10 to 200 hours. The binder removal treatment is performed while maintaining the temperature or holding.

  Then, as shown in FIG. 9, the ultra-high pressure molded body 40 or the binder-treated ultra-high pressure composite sintered body molded body (composite structure molded body 56) is formed on the metal-enriched region forming surface of the backing supports 4 and 24. Is integrated into the backing supports 4 and 24 by being set in an ultra-high pressure apparatus in a state of being mounted on the substrate, and fired and integrated at a pressure of 4 to 6 GPa, a temperature of 1350 to 1600 ° C. for 1 to 60 minutes. The ultrahigh pressure sintered structure 6 or the ultrahigh pressure composite sintered structure 26 can be produced.

  The structures 6 and 26 are processed into a cutting edge chip shape by a wire electric discharge machine, cutting, polishing, or the like.

  A cutting edge chip in which the backing supports 4 and 24 and the ultrahigh-pressure sintered structure 6 or the ultrahigh-pressure composite sintered structure 26 are integrated is attached to the corners of the tool bodies 2 and 22. The seats 3 and 23 are brazed using silver solder or the like.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited only to a following example.

The cemented carbide for backing support prepared in the composition shown in Table 1 was molded and fired under the conditions shown in Table 1. The obtained cemented carbide was cut and cross-sectional observed, and concentration analysis was performed by EPMA analysis in the depth direction from the vicinity of the surface. The cobalt (Co) concentration D _s in the metal-enriched layer and the internal cobalt (Co) concentration was by comparing the D _c obtains the value of D _{s /} D _c, cemented carbide a as shown in Table 1, metal enriched layer near the surface for the B had been formed.

The obtained cemented carbide was ground on only one side to obtain a backing support having a thickness of 3 mm.

  Next, diamond particles having an average particle diameter of 1 to 5 μm and Co powder were adjusted and mixed to the composition shown in Table 2, and molded to produce an ultra-high pressure molded body.

  Moreover, the molded object for ultra-high pressure compound sintered compacts was produced with the following method.

First, a diamond powder having an average particle diameter of 1 to 5 μm is kneaded with cellulose and polyethylene glycol as organic binders and 100 parts by volume of polyvinyl alcohol as a solvent in a total amount, and press-molded into a cylindrical shape having a diameter of 20 mm. The molded object for core materials was produced (sample No. 1-4).

  On the other hand, the WC powder having an average particle diameter of 1 μm and Co powder having an average particle diameter of 3 μm are mixed and pulverized to the composition shown in Table 3, and the same organic binder and solvent as those for the core material are added and kneaded to form a coating layer. Two coating layer molded bodies having a shape thickness of 1 mm were produced by press molding, and these were arranged so as to cover the outer periphery of the core material molded body to produce a composite fiber body.

  Then, the composite fiber body is coextruded to produce an elongated single core fiber molded body having a diameter of 1 mm, and then 100 of the stretched composite molded bodies are converged and coextruded again, and the diameter is 1 mm. A multifilament fiber molded body having a multifilament structure was produced.

  Next, the composite fiber body having the multifilament structure was cut to a length of 100 mm, aligned in parallel to form a sheet, and three composite sheets were laminated to produce a laminate. Further, the binder was subjected to binder removal treatment by raising the temperature of the laminate to 300 to 700 ° C. over 100 hours to obtain an ultra-high pressure composite molded body (composite structure molded body 56) (Sample Nos. 5 to 8).

  The obtained ultra-high pressure molded body and ultra-high pressure composite structure molded body were placed directly on the burned surface of the cemented carbide backing support and inserted into a capsule which was a jig for ultra-high pressure sintering. . Sample No. As for Nos. 4 and 8, about 0.1 g of Co powder was filled at the interface between the backing support and the above-mentioned molded product having the composition shown in Tables 2 and 3.

  Then, this capsule is placed in an ultra-high pressure firing apparatus, fired at 5.5 GPa and 1400 ° C. for 15 minutes, and an ultra-high pressure (composite) sintered structure in which the ultra-high pressure (composite) sintered body and the backing support are integrated. The body was made.

  Thereafter, the capsules on the upper and lower surfaces of this structure were removed by grinding, and the backing support was further ground to obtain a cutting edge tip thickness of 2 mm. Further, when the cross section of the sintered body was observed, it was confirmed that the thickness of the diamond ultrahigh pressure sintered body layer was constant at about 0.4 mm for all samples.

In addition, SEM observation was performed on the cross section of each sample, concentration analysis was performed by EPMA analysis in the depth direction from the vicinity of the surface, cobalt (Co) concentration distribution near the interface was measured, and concentration mapping was taken. This mapping, those cobalt concentration c is in the concentration range of concentration C _h of cobalt wherein the backing support inside portion of the cobalt concentration C _w ultrahigh pressure sintered composite body section ○, the range in each location An evaluation was given as x where there was a point to be removed. Furthermore, the patterns with the most similar mapping of each sample in the light of the cobalt concentration distribution patterns (a) to (c) in FIG.

Further, with respect to this sintered body, with the surface of the ultra-high pressure (composite) sintered body facing down, a load was applied by the same measuring method as the 4-point bending test with an upper span of 3 mm and a lower span of 8 mm, The load at which the bonded layer began to peel from the cemented carbide backing support was evaluated as adhesion strength (peel strength). The results are shown in Tables 2 and 3.

  As is clear from Table 2, the sample No. In 1, 2, 5, and 6, the ultra-high pressure (composite) sintered body and the backing support had excellent adhesion strength.

  Sample No. 1 also has a point in which the cobalt concentration falls outside the range using a cemented carbide backing support that does not form a metal-enriched region in the vicinity of the interface. In 3, 4, 7, and 8, the adhesion strength was not sufficient, and peeling occurred with a small load. Furthermore, sample No. 1 has a point in which the cobalt concentration is out of the range by filling the interface between the ultra-high pressure (composite) molded body and the backing support with cobalt powder. 4 and 8 also sample No. Although the adhesion strength was superior to those of 3 and 7, the adhesion strength was still insufficient, and peeling occurred with a small load.

(Cutting tools)
Furthermore, using the produced sintered body, a tool body having a shape of TNMA 160404 as shown in FIG. 2 was brazed with silver brazing to produce a cutting tool. A cutting test is performed on the obtained cutting tool under the condition that the following intermittent cutting performance is required, and the number of workpieces (up to 4000 pieces) before the occurrence of chipping or chipping is evaluated and 4000 pieces are processed. About the produced sample, the amount of wear at that time was measured. The results are shown in Table 4.

(Cutting conditions)
<Intermittent cutting test>
Work Material: High Silicon Aluminum (Al-12% Si) 4 Groove Cutting Speed: 250m / min
Feed: 0.2mm / ref
Cutting depth: 2mm
Cutting state: dry

  From Table 4, Sample No. in which the metal-enriched layer was not provided on the backing support. In Nos. 3 and 7, the ultra-high pressure sintered body dropped out during cutting, making it impossible to continue the test. In addition, sample No. 1 was obtained by sandwiching cobalt powder between the ultrahigh pressure sintered body and the backing support. In Nos. 4 and 8, the ultra-high pressure sintered body did not fall off, but was lost early.

  On the other hand, according to the present invention, sample No. 1 produced using a backing support having a metal-enriched region on the surface. In 1, 2, 5, and 6, the high-pressure sintered body did not fall off and exhibited excellent fracture resistance. In particular, sample No. using an ultra-high pressure composite sintered body. Samples 5 and 6 showed particularly excellent fracture resistance.

It is (a) perspective view which shows one Embodiment of the throw away tip which used the ultrahigh pressure sintered structure concerning this invention as a cutting blade tip, (b) It is a fragmentary sectional view of cutting blade tip vicinity. It is (a) perspective view which shows one Embodiment of the throw away tip which used the ultrahigh pressure sintered structure concerning this invention as a cutting blade tip, (b) It is a fragmentary sectional view of cutting blade tip vicinity. It is a schematic diagram which shows the distribution state of cobalt in the interface vicinity of an ultrahigh pressure sintered compact and a backing support body about the ultrahigh pressure (composite) sintered structure of this invention. It is a perspective view which shows the structure of the composite fiber body of the cutting tool concerning this invention.

  (A) It is a schematic perspective view which shows an example of the single core fiber body of a single structure.

(B) It is a schematic perspective view which shows an example of the multifilament fiber body of a multifilament structure.
(A)-(d) is a figure for demonstrating the arrangement | positioning method of the composite fiber body in the ultra-high pressure (composite) structure sintered compact concerning this invention. (A)-(d) is process drawing which shows the manufacturing method of a single type single core fiber molded object about the ultra-high pressure compound sintered structure concerning this invention. It is process drawing which shows the manufacturing method of a multi-type multi-core fiber molded object about the ultra-high pressure compound sintered structure concerning this invention. It is a figure for demonstrating the modification of the manufacturing method of the ultra-high pressure compound sintered structure concerning this invention. It is a figure for demonstrating the arrangement | positioning state of the molded object at the time of baking the ultrahigh pressure (composite) sintered structure concerning this invention.

Explanation of symbols

1, 21 Cutting tool 2, 22 Tool body 3, 23 Mounting base 4, 24 Backing support 5 Ultra high pressure sintered body 25 Ultra high pressure composite sintered body 6 Ultra high pressure sintered structure 26 Ultra high pressure composite sintered structure 7 27, brazing material 8, 28 rake face 9, 29 flank face 10, 30 cutting edge 11, 31 mounting hole 40 super high pressure molded body 51 core material 51a core material molded body 52 coating layer 52a coating layer molded body 53 composite fiber Body 53a Molded body 53s Single structure single core fiber body 53m Multifilament structure multicore fiber body 55 Composite sheet 56 Composite structure molded body 60 Roller 61 Composite laminated molded body

Claims (8)

An ultra-high pressure sintered structure in which an ultra-high pressure sintered body is bonded to the surface of a backing support made of a cemented carbide containing at least cobalt as a binding metal, the backing support, the ultra-high pressure sintered body, in the concentration distribution of the cobalt in the interface, the concentration c of the vicinity of the interface cobalt is present in the concentration range of concentration C _h of cobalt wherein the backing support inside portion of the cobalt concentration C _w ultrahigh pressure sintering body portion Ultra high pressure sintered structure. An ultra-high-pressure composite sintered body in which a plurality of fibrous core materials made of an ultra-high-pressure sintered body are bonded with a hard sintered body, and a backing support made of a cemented carbide containing at least cobalt as a binding metal. An ultra-high pressure composite sintered structure bonded to a surface, wherein in the cobalt concentration distribution at the interface between the backing support and the ultra-high pressure composite sintered body, the cobalt concentration c in the vicinity of the interface is the backing support. ultrahigh pressure composite sintered structure wherein a concentration C _w of the interior of the cobalt present in the concentration range of concentration C _c of cobalt ultra high pressure sintered composite body portion. The ultra-high pressure composite sintered structure according to claim 2, wherein the hard sintered body is made of a cemented carbide. An ultra-high pressure sintered body material is placed on the metal-enriched region forming surface of a backing support made of a cemented carbide containing at least cobalt as a binding metal and having a cobalt-enriched region having a high cobalt concentration on the surface. And the manufacturing method of the super-high pressure sintered structure which bakes under high temperature and ultra-high pressure. The ratio D _s / D _c between the cobalt concentration D _c inside the backing support and the cobalt concentration D _{s on the} surface of the backing support is 1.05 or more for the backing support before firing. Manufacturing method of ultra-high pressure sintered structure. A fiber made of a raw material of an ultra-high pressure sintered body on the metal-enriched region forming surface of a backing support comprising a cemented carbide containing at least cobalt as a binding metal and having a cobalt-enriched region having a high cobalt concentration on the surface. Of an ultra-high-pressure composite sintered structure in which an ultra-high-pressure composite molded body in which a plurality of core-shaped core molded bodies are bonded by a hard sintered body raw material molded body is placed and fired at high temperature and ultra-high pressure Production method. The ratio D _s / D _c between the cobalt concentration D _c inside the backing support and the cobalt concentration D _{s on the} surface of the backing support is 1.05 or more with respect to the backing support before firing. Manufacturing method of ultrahigh pressure composite sintered structure. The ultra-high pressure sintered structure according to claim 1 or the backing support of the ultra-high pressure composite sintered structure according to claim 2 or 3 is bonded to a predetermined position of a tool base, Cutting tool with ultra high pressure composite sintered body as tool cutting edge.

Images