JP2006255853A - Sintered tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sintered tool provided with high welding resistance, wear resistance, and flaking resistance by preventing the occurrence of flaking caused by wear and impact due to welding or diffusion of a workpiece. <P>SOLUTION: The sintered tool 11 is composed by using a composite structure 16 composed by coating the outer peripheral face of a long core material, which is composed of a diamond sintered body formed by joining between diamond particles with an iron group metal, with an outer skin material composed of a sintered alloy formed by joining one or more kinds of hard particles among the carbide, nitride, and carbonitride of at least one kind of metal element selected from the groups IVa, Va, and VIa metals in the periodic table with the iron group metal. The outer skin material contains 1-45 vol.% of a carbon nanotube 32 in which directions of fibers are oriented in one direction. At least an angle θ formed by the orientation direction of the carbon nanotube 32 and a rake face 15 is 45-90 degrees at the cutting edge part in the sintered tool. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sintered tool using a composite fiber body in which a long core material is covered with a skin material.

  Conventionally, in order to improve the toughness as well as the hardness and strength of the material, the outer peripheral surface of the long core formed of a sintered body of metal oxide, carbide, nitride, carbonitride, etc. A composite fiber body (fibrous composite material) coated with a skin material formed of a sintered body is known. As this composite fiber body, what was described in patent document 1, for example is mentioned.

  However, in the sintered tool using the conventional composite fiber body as described in this document, it is difficult to obtain what has the required high hardness and strength and excellent toughness. As a result, there is a problem that wear resistance in cutting and excavation cannot be obtained. In particular, the skin material is easily welded to the workpiece and has a large amount of wear.

  By the way, diamond is the hardest substance, and it is known that a diamond-like sintered body using the diamond has excellent wear resistance. For this reason, diamond-like sintered bodies are used in various tools such as cutting tools and excavating tools, and in fields where wear resistance such as a drawing die is required.

  In general, a diamond sintered body uses an iron group metal such as Co as a binder. In Patent Document 2, in a diamond tool for machining, a diamond crystal is directly bonded to an adjacent diamond crystal, and a lump of diamond crystal material is directly bonded to a lump of a sintered carbide support material (binding material). The composite (diamond sintered body) is described. In this diamond sintered body, diamond powder is placed on a WC-Co cemented carbide base material, and then a Co or Co-WC eutectic liquid phase is converted from the cemented carbide base material to the diamond powder under high temperature and pressure. It is obtained by infiltrating inside and sintering.

  However, the diamond sintered body holds the diamond particles with a binder such as an iron group metal in order to prevent the diamond particles from falling off. For this reason, the temperature of a tool rises during cutting of Al-Si alloy or Ti alloy. This temperature increase is particularly large on the rake face of the tool. As a result, the workpiece is welded to the rake face, and the diamond particles are peeled off by the welding, resulting in wear due to diffusion of the workpiece components into the tool (crater wear). There is a problem of progress. Further, since the diamond sintered body has high hardness and low toughness, there has been a problem of flaking in which the rake face side is largely peeled off when the mineral particles collide violently as in excavation.

US Pat. No. 6,063,502 Japanese Examined Patent Publication No. 52-12126

  The object of the present invention is to prevent wear due to welding of workpieces and diffusion of workpiece components into the tool, and to prevent flaking due to impact, and is excellent in welding resistance, wear resistance and flaking resistance. Is to provide a sintered tool.

  As a result of intensive studies to solve the above problems, the present inventor has obtained a composite fiber body in which the outer peripheral surface of a long core made of a diamond-like sintered body is covered with a skin material made of a sintered alloy. In the sintered tool used, the skin material contains a predetermined amount of carbon nanotubes oriented in a specific direction, taking advantage of the high thermal conductivity and toughness that are the characteristics of carbon nanotubes. Since the heat generated at the contact surface between the blade and the workpiece can be effectively diffused and released throughout the tool, welding of the workpiece and diffusion of the welded workpiece into the tool can be prevented. It was found that by dispersing the impact energy at the time, flaking is prevented and a sintered tool having excellent welding resistance, wear resistance and flaking property can be obtained.

  More specifically, a rake whose temperature rises most during processing is obtained by containing a predetermined amount of carbon nanotubes in the skin material and arranging the orientation direction of the carbon nanotubes to be 45 to 90 ° with respect to the rake face. The heat generated on the surface is effectively released, wear due to welding and diffusion of the work piece can be suppressed, and impact energy during processing that causes flaking is absorbed by the carbon nanotubes being dispersed, The progress of cracks can be suppressed.

That is, the sintered tool of the present invention for solving the above problems has the following configuration.
(1) At least one metal element selected from the periodic table 4a, 5a, and 6a group metals on the outer peripheral surface of the long core material composed of the diamond sintered body in which the diamond particles are bonded with the iron group metal A sintered tool using a composite fiber body formed by coating a skin material composed of a sintered alloy in which one or more hard particles of carbides, nitrides, and carbonitrides are bonded with an iron group metal, The skin material contains 1 to 45% by volume of carbon nanotubes whose fibers are oriented in one direction, and at least the angle θ between the orientation direction of the carbon nanotubes at the cutting edge and the rake face is 45 to 90 °. A sintered tool characterized by
(2) The sintering tool according to (1), wherein the core material contains 1 to 45% by volume of carbon nanotubes whose fibers are oriented in one direction.
(3) The sintered tool according to (1) or (2), wherein an average diameter of the carbon nanotube is 1 to 500 nm and an aspect ratio is 2 to 500 in cross-sectional observation of the composite fiber body.
(4) A part or all of the surface of the carbon nanotube is at least one metal selected from Group 4a, 5a and 6a metals of the periodic table, Al and Si, or carbide, nitride and carbonitride of the metal The sintered tool according to any one of (1) to (3), which is coated with at least one of the above.
(5) The tool body and a cutting edge chip brazed to a mounting seat of the tool body, and at least the cutting edge portion of the cutting edge chip is formed of the composite fiber body. A sintered tool according to the above.

  According to the invention described in (1) above, there is an effect that a long-life sintered tool having high welding resistance, wear resistance, and flaking resistance can be obtained. According to the invention described in (2) above, since the core material contains carbon nanotubes oriented in a predetermined direction, the thermal conductivity of the sintered body is increased, and the heat generated by the cutting blade is increased. The whole can be escaped quickly. As a result, high welding resistance can be obtained even when the cutting edge is likely to become high temperature and the workpiece is easily welded as in dry processing. According to the invention described in (3) above, it is possible to enhance the fiber reinforcing action of the carbon nanotubes and to exhibit excellent strength and toughness. According to the invention described in (4) above, the carbon nanotubes are oxidized and decomposed during firing, or the carbon nanotubes are dissolved in the binder phase (iron group metal in the skin material) during sintering, and the carbon nanotubes become thin. Therefore, it is possible to prevent the original effect from being exhibited. According to the invention described in (5) above, since the cutting edge tip is brazed to the mounting seat of the tool body, the fiber direction of the carbon nanotubes in the sintered body depends on the shape of the cutting edge portion of the tool. In addition, the arrangement of the carbon nanotubes in the sintered body can be easily adjusted even when cutting edges are provided at a plurality of corners.

Hereinafter, a sintering tool according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing a composite fiber body constituting the sintered tool of the present embodiment. FIG. 2 is a perspective view showing the sintering tool according to the present embodiment. FIG. 3 is a schematic sectional view showing the vicinity of the cutting edge tip of the sintering tool according to the present embodiment.
(Composite fiber)
As shown in FIG. 1, the composite fiber body 1 has a structure in which an outer peripheral surface of a long core material 2 is covered with a skin material 3.

  The core material 2 is composed of a diamond sintered body in which diamond particles are bonded with an iron group metal. The average particle diameter of the diamond particles is preferably 50 μm or less, more preferably 0.1 to 10 μm. Examples of the iron group metal include Fe (iron), Co (cobalt), and Ni (nickel). Among these, containing Co as an essential component is desirable in that it can suppress the degranulation of diamond particles, and further comprising only Co as an iron group metal when used as a cutting tool to increase the bonding force of diamond particles. It is desirable in terms of welding resistance. Further, the content is desirably 4 to 10% by volume.

  The content of diamond particles in the diamond sintered body is preferably 50 to 98% by volume, more preferably 75 to 92% by volume. When the content of diamond particles is within this range, hardness as a sintered body can be maintained to maintain wear resistance as a tool, and diamond particles can be held firmly to prevent diamond particles from falling out. It is possible to suppress the progress of wear.

The skin material 3 is a burn-in bond in which one or more hard particles of carbides, nitrides, and carbonitrides of at least one metal element selected from the group 4a, 5a, and 6a metals of the periodic table are bonded with an iron group metal. Made of gold. Examples of the hard particles include at least one selected from the group consisting of WC, TiC, TiCN, TiN, TaC, NbC, ZrC, ZrN, VC, Cr ₂ C, and Mo ₂ C. Moreover, as an iron group metal, the thing similar to what was illustrated with the core material 2 is mentioned. The hard particles described above may be contained in the diamond sintered body constituting the core material 2 in a proportion of 10% by volume or less.

  The skin material 3 contains 1 to 45% by volume of carbon nanotubes in which the direction of the fibers is oriented in one direction. If the content of carbon nanotubes is less than 1% by volume, the effect of containing carbon nanotubes will not be exhibited. If the content is more than 45% by volume, aggregates of carbon nanotubes will be generated, and these aggregates will become fracture sources and become deficient. May occur.

  In the carbon nanotube, the direction of the fibers is aligned in one direction. And the angle (theta) which the orientation direction of a carbon nanotube and the rake face in at least the cutting edge part of the sintering tool mentioned later make is 45-90 degrees, Preferably it is 80-90 degrees. The orientation direction and angle θ of the carbon nanotube in the present invention can be measured using, for example, a scanning electron microscope (SEM) described later.

  The core material 2 preferably contains 1 to 45% by volume of carbon nanotubes whose fibers are oriented in one direction. Thereby, the thermal conductivity of the composite fiber body 1 is increased, and the heat generated at the cutting edge can be quickly released from the entire sintered body. Further, when the content of the carbon nanotube is within the above range, the carbon nanotube does not aggregate and become a source of destruction. In the carbon nanotube, the angle θ between the carbon nanotube and the rake face in the cutting edge portion of the sintered tool is 45 to 90 °, preferably 80 to 90 °, as exemplified in the skin material 3. Is good.

  The carbon nanotube in the present invention means a carbon tube having a cylindrical fiber shape with a diameter of 1 μm or less. In the present invention, in the cross-sectional observation of the composite fiber body 1, it is preferable that the average diameter of the carbon nanotubes is 1 to 500 nm and the aspect ratio is 2 to 500, and in particular, the average diameter is 5 to 200 nm and the aspect ratio is 5 to 200. This is more preferable for making the characteristics of the carbon nanotubes more effective, increasing the dispersibility and orientation of the nanotubes in the sintered body, and increasing the strength of the sintered body. In addition, the cross-section observation of the composite fiber body 1 is performed by cutting the composite fiber body and observing the cross section using a scanning electron microscope (SEM) or the like.

  When the average diameter of the carbon nanotubes is in the range of 1 nm to 500 nm, the carbon nanotubes can be uniformly mixed and dispersed in the skin material 3 and the core material 2, and the possibility of becoming a breakage source is reduced. In addition, when the aspect ratio of the carbon nanotube is within the range of 2 to 200, the effect (fiber reinforcing action) obtained from the fiber shape of the carbon nanotube is exhibited, and it is also possible to uniformly disperse by a conventionally known mixing method It is.

  Further, the carbon nanotube has at least a part of the surface thereof at least one metal selected from Group 4a, 5a, 6a metal of the periodic table, Al (aluminum) and Si (silicon), or a carbide of the metal. It is preferable to coat with at least one of nitride and carbonitride. Thereby, it can suppress the fall of the fiber reinforcement effect | action by being oxidized and decomposed | disassembled during baking or melt | dissolving in the iron group metal which functions as a binder phase, and can improve the oxidation resistance during a process. In particular, in the present invention, Ti (titanium) and Si (silicon), which are simple in terms of manufacturing method, are desirable as the material for coating the carbon nanotubes, and the coating is particularly effective when used for thinner carbon nanotubes. .

  Examples of the periodic table groups 4a, 5a, and 6a, at least one metal selected from Al (aluminum) and Si (silicon), and the carbide, nitride, and carbonitride of the metal include, for example, metal Ti, One type or two or more types selected from the group of metals Si, TiC and SiC can be used.

(Sintered tool)
Next, an embodiment of a sintered tool using the composite fiber body 1 as a part of the material will be described. As shown in FIGS. 2 and 3, the sintered tool 11 has a flat plate shape, and a back plate 19 and a composite structure 16 are integrated with a mounting seat 13 formed at one corner of the tool body 12. The cut edge tip 14 is brazed. The composite structure 16 has a structure in which a plurality of composite fiber bodies 1 in which the core material 2 is covered with the skin material 3 are converged by a manufacturing method described later. In the sintering tool 11, a cutting edge 17 is formed at the intersecting ridge line portion between the rake face 15 and the flank face 20. Furthermore, an attachment hole 18 through which a clamp screw or the like for attaching to a tool such as a cutting tool is inserted is formed at the center of the sintered tool 11.

  As shown in FIG. 3, the core material 2 and the skin material 3 of the composite structure 16 are unidirectional so that the orientation of the carbon nanotube fibers coincides with the fiber direction of the core material 2 and the skin material 3 as a whole. So that the fiber directions of the core material 2 and the skin material 3 of the composite fiber body 1 form an angle θ = 45 to 90 ° with respect to the rake face 15 of the sintered tool 11. Oriented. The angle θ formed by the orientation direction of the carbon nanotube 32 and the rake face 15 is preferably 80 to 90 °. Thereby, the heat which generate | occur | produced in the rake face 15 during a process can be escaped effectively, the temperature rise of the rake face 15 can be suppressed, and the abrasion by welding and spreading | diffusion of a workpiece can be suppressed.

  For example, as shown in FIG. 3, the orientation direction of the carbon nanotube 32 and the angle θ are obtained by cutting the sintered tool 11 perpendicularly from the rake face 15, and using a scanning electron microscope (SEM) or the like for the cross section. The fiber direction and length of 32 are specified, the direction vector of the whole nanotube 32, that is, the orientation direction of the nanotube 32, is calculated from the sum of the direction vectors of each nanotube 32 in one visual field, and the orientation direction of the carbon nanotube and the rake face 15 are calculated. Can be obtained. In addition, when the breaker is formed in the rake face 15 of the sintering tool 11, the rake face used for calculation of the angle θ is calculated by using the seating surface 21 in contact with the holder of the sintering tool 11 instead.

According to the present invention, the sintered tool may be a solid-type tool, but is a low-cost, easy-to-manufacture tool, or a throw-away tool or a brazing tool in which only the cutting edge is brazed. It is desirable. Further, as shown in FIGS. 2 and 3, by cutting out the cutting edge portion of the tool body 12 and fitting the cutting edge tip 14 having the composite structure 16 into the mounting seat 13 and fixing by brazing or the like, The orientation direction of the carbon nanotube 32 with respect to the cutting edge shape of the tool can be easily controlled. Further, when providing cutting edges at a plurality of corners, there is an advantage that the carbon nanotubes 32 can be easily arranged.
Note that the sintered tool of the present invention can be suitably used for excavation and wear resistance applications in addition to the cutting applications described above.

<Manufacturing method>
Hereinafter, an example of the manufacturing method of the sintered tool in this invention is demonstrated in detail with reference to drawings. 4 and 5 are schematic views showing a manufacturing method for producing a composite molded body, and FIG. 6 is a schematic view showing a method for forming the composite molded body into a composite disk.

(Molded core material)
First, the aforementioned diamond powder and iron group metal are mixed, and if necessary, carbon nanotubes, sintering aid component powder, organic binder, plasticizer, solvent, dispersant, lubricant, etc. are added to the mixture and kneaded. . Next, as shown in FIG. 4A, the obtained mixture is molded into a cylindrical shape by a molding method such as press molding or cast molding to produce a core compact 50. Here, in order to obtain a homogeneous composite molded body by coextrusion molding to be described later, the amount of the organic binder added is desirably 30 to 70% by volume, particularly 40 to 60% by volume.

  As the organic binder and plasticizer, for example, paraffin wax, polystyrene, polyethylene, ethylene-ethyl acrylate, ethylene-vinyl acetate, polybutyl methacrylate, polyethylene glycol, dibutyl phthalate and the like can be used. As the solvent, dispersant and lubricant, for example, polyethylene glycol, mineral oil, butyl oleate, stearic acid and the like can be used.

(Skin for skin material)
After mixing the hard particles, iron group metal and carbon nanotubes to obtain a mixture, if necessary, add the above-mentioned sintering aid component powder, organic binder, plasticizer, solvent, etc. to the mixture and mix To do. Next, as shown in FIG. 4B, the obtained mixture is molded into a half-cylindrical shape by a molding method such as press molding or cast molding to produce two skin material molded bodies 51 and 51. Then, as shown in FIG. 4C, the obtained skin material molded bodies 51, 51 are arranged so as to cover the outer peripheral surface of the core material molded body 50 obtained above, and a molded body 52 is produced. To do.

(Extrusion molding)
Next, as shown in FIG. 4 (d), by using the extruder 100, the molded body 52 is extrusion-molded (core material molded body 50 and skin material molded bodies 51, 51 are co-extruded). Then, the core material molded body 50 is covered with the skin material molded body 51 to produce a composite molded body 53 that is elongated to a small diameter. At this time, the fiber direction of the composite molded body 53 and the fiber direction (orientation direction) of the aligned carbon nanotubes are aligned in the same direction. Although the orientation in the extrusion direction can be controlled by the shear rate at the time of extrusion molding, the size of the discharge port, and the like, it can also be more effectively oriented by creating an electric field at the discharge portion.

  In addition, as shown in FIG. 5, a composite molded body 55 in which carbon nanotubes are more oriented may be produced by extruding a converging body 54 in which a plurality of composite molded bodies 53 are converged. The cross sections of the composite molded bodies 53 and 55 can be formed into an arbitrary shape such as a triangle, a quadrangle, a pentagon, a hexagon, and an ellipse in addition to a circle by changing the outlet shape of the extruder 100.

  Then, as shown in FIG. 6A, the long composite molded body 55 is further bundled to form the converging body 56, and the converging body 56 is heated and pressurized in the mold 101. Next, as shown in FIG. 6B, the rod-shaped molded body 57 obtained by heating and pressing can be cut along a plane perpendicular to the longitudinal direction to obtain a composite disk 58. Note that a composite molded body 53 may be used instead of the composite molded body 55.

  Then, the composite disc 58 is placed on the back plate 19 shown in FIG. 2 made of cemented carbide. At this time, as a specific mounting direction of the composite disc 58, a plurality of the composite discs 58 arranged in a direction perpendicular to the plane direction of the composite disc 58 by arranging the plane of the composite disc 58 in parallel with the plane of the back plate 19. The fiber direction of the composite molded body 55, that is, the fiber direction of the carbon nanotube 32 contained in the composite molded body 55 is arranged to be perpendicular to the back plate 19.

(Baking)
Subsequently, the composite disk 58 placed on the back plate 19 is subjected to binder removal treatment by heating or holding at 300 to 700 ° C. for 10 to 200 hours. And the composite structure 16 joined and integrated with the back plate 19 by being set in an ultra high pressure apparatus and integrated by firing at a pressurized pressure of 4 to 6 GPa, 1350 to 1600 ° C. for 1 to 60 minutes, A cutting blade tip 14 made of can be produced. The composite structure 16 has a structure in which a plurality of composite fiber bodies 1 are converged as shown in FIG.

  The cutting edge tip 14 obtained above is cut into a predetermined shape with a wire electric discharge machine and processed into a cutting edge shape by cutting, polishing, or the like. Next, the sintered tool 11 shown in FIG. 2 can be obtained by brazing the cutting edge tip 14 to the mounting seat 13 using a silver solder or the like.

  Hereinafter, although the sintering tool of the present invention will be described in more detail with reference to examples and comparative examples, the present invention is not limited to the following examples.

[Example]
<Production of sintered tools>
In combinations shown in Table 1, diamond particles having an average particle diameter of 1.5 μm, Co powder having an average particle diameter of 1.0 μm, carbon nanotubes having an average diameter of 20 nm and a length of 1 μm to 3 μm, or an average diameter of 150 nm and a length of 4 μm to 6 μm carbon nanotubes are mixed in the ratio shown in Table 1, cellulose and polyethylene glycol are kneaded as organic binder, and polyvinyl alcohol is kneaded as a solvent, and extruded into a cylindrical shape to produce a core material. did. The total addition amount of the organic binder and the solvent was the same amount (volume) as the total volume of diamond particles, Co powder, and carbon nanotubes.

Next, in the combinations shown in Table 1, a WC powder having an average particle size of 2.0 μm, a Co powder having an average particle size of 1.0 μm, a carbon nanotube having an average diameter of 20 nm and a length of 1 μm to 3 μm, or an average diameter of 150 nm, a length 4 μm to 6 μm of carbon nanotubes were mixed, and the same organic binder and solvent as above were added and kneaded to produce two half-cylindrical skin material molded bodies by extrusion molding. Subsequently, these molded bodies for skin materials were arranged so as to cover the outer periphery of the molded body for core materials, and molded bodies were produced. Here, carbon nanotubes having an average diameter of 20 nm are placed in an alumina crucible in which Si / SiO ₂ mixed powder is placed in advance and subjected to coating treatment at 1300 ° C. in vacuum, and the surface of the carbon nanotubes is coated with SiC. It was.

  Then, the molded body was extruded to produce a stretched composite molded body having a diameter of 2 mm. The stretched composite molded body was cut into thin pieces with a microtome and observed with a scanning transmission electron microscope (STEM). The added carbon nanotubes were clearly oriented in the extrusion direction (fiber longitudinal direction). .

  The composite molded body obtained above is press-molded into a cylindrical shape with a diameter of 10 mm to produce a rod-shaped molded body, and this rod-shaped molded body is cut along a plane perpendicular to the longitudinal direction to produce a composite disc. did. Thereafter, a back plate made of a cemented carbide of 5 mm thick is disposed on the lower surface of the composite disc, and after the binder removal treatment is performed by raising the temperature from 300 to 700 ° C. in 100 hours. Then, it was placed in an ultra-high pressure apparatus and fired at 1450 ° C. for 10 minutes to produce a cutting edge chip in which the composite structure and the back plate were integrated. After sintering, it was confirmed that the carbon nanotubes in the cutting edge tip were oriented in one direction. Thereafter, each of the cutting edge chips was processed and brazed at 700 ° C. using a silver brazing to a mounting base of a tool body made of a cemented carbide to prepare sintered tools (sample No. 1 in Table 1). ~ 7).

  Here, with respect to the sintered tool obtained above, the angle θ formed by the fiber direction of the carbon nanotubes in the composite sintered body and the rake face of the cutting edge tip was measured, and the results are shown in Table 2. The angle θ was obtained by cutting the sintered tool perpendicularly from the rake face, observing the cross section with a scanning electron microscope (SEM), and calculating the sum of the fiber vectors of each nanotube.

  Table 1 shows the diameter and aspect ratio of the carbon nanotubes in the composite structure. These diameters and aspect ratios were obtained by cutting the composite structure and observing its cross section using a scanning electron microscope (SEM). Specifically, SEM observation was performed at five locations on the cross section of the composite structure, and the total number of carbon nanotubes present in a range of 5 μm × 5 μm was measured, and the average value was calculated.

[Comparative Example 1]
A composite disk was prepared in the same manner as in the Examples except that carbon nanotubes were not added (Sample No. 10) or carbon nanotube content was added at a rate exceeding 45% by volume (Sample No. 8). did. Then, using the obtained composite disc, sintered tools were respectively produced in the same manner as in the examples.

[Comparative Example 2]
Except for adjusting the direction of the composite sintered body so that the angle θ formed by the orientation direction of the carbon nanotube and the rake face is smaller than 45 ° and brazing the back plate (Sample No. 9) A composite disc was produced in the same manner as described above. Then, using the obtained composite disc, sintered tools were respectively produced in the same manner as in the examples.

<Sintering tool evaluation method>
For each sintered tool produced in the above process, a plurality of workpieces (AC4B, with 4 grooves) are cut, and the number of workpieces processed until welding, wear and flaking occur (up to 3000 pieces) ) Was evaluated. The evaluation conditions are shown below, and the evaluation results are also shown in Table 2.
(Evaluation conditions for the number of workpieces processed)
Cutting depth d = 1mm
Cutting speed V = 1000 m / min feed f = 0.1 mm / rev
Dry cutting

  As can be seen from Table 2, the sample No. 1 contained less than 1% by volume of carbon nanotubes. In No. 10, welding occurred early. In addition, Sample No. with a carbon nanotube content greater than 45% by volume. In No. 8, the composite sintered body was lost at the cutting edge. Further, the sample No. 5 in which the angle θ formed by the orientation direction of the carbon nanotube and the rake face of the sintered tool is smaller than 45 °. 9 also caused welding to occur relatively early.

  On the other hand, according to the present invention, sample No. 1 containing carbon nanotubes in a proportion of 1 to 45% by volume and having an angle θ between the orientation direction and the rake face of 45 ° to 90 °. In 1 to 7, all showed excellent cutting performance. In addition, Sample No. in which carbon nanotubes were also contained in the core material. In Nos. 5 to 6, the welding resistance was higher.

It is a perspective view which shows the composite fiber body which comprises the sintering tool of this embodiment. It is a perspective view which shows the sintering tool of this embodiment. It is a schematic sectional drawing which shows the cutting-edge chip | tip vicinity of the sintering tool concerning this embodiment. (A)-(d) is the schematic which shows the manufacturing method which produces a composite molded object. It is the schematic which shows the manufacturing method which produces another composite molded object. (A), (b) is the schematic which shows the method of shape | molding a composite molded object to a composite disk.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Composite fiber body 2 Core material 3 Skin material 11 Sintering tool 12 Tool main body 13 Mounting seat 14 Cutting blade tip 15 Rake face 16 Composite structure 17 Cutting edge part 18 Mounting hole 19 Back plate 20 Flank 21 Seating surface 32 Carbon nanotube 50 Molded body for core material 51 Molded body for skin material 52 Molded body 53, 55 Composite molded body 54, 56 Converged body 58 Composite disk

Claims (5)

A carbide of at least one metal element selected from Periodic Tables 4a, 5a, and 6a metals on the outer peripheral surface of a long core material made of a diamond sintered body in which diamond particles are bonded with an iron group metal; A sintered tool using a composite fiber body formed by coating a skin material made of a sintered alloy in which one or more hard particles of nitride and carbonitride are bonded with an iron group metal,
The skin material contains 1 to 45% by volume of carbon nanotubes whose fibers are oriented in one direction, and at least the angle θ between the orientation direction of the carbon nanotubes at the cutting edge and the rake face is 45 to 90 °. A sintered tool characterized by that.   2. The sintered tool according to claim 1, wherein the core material contains 1 to 45% by volume of carbon nanotubes in which fibers are oriented in one direction.   3. The sintered tool according to claim 1, wherein an average diameter of the carbon nanotubes is 1 to 500 nm and an aspect ratio is 2 to 500 in cross-sectional observation of the composite fiber body.   A part or all of the surface of the carbon nanotube is at least one metal selected from Group 4a, 5a, 6a metal of the periodic table, Al and Si, or at least one of carbide, nitride and carbonitride of the metal. The sintered tool according to any one of claims 1 to 3, which is coated with seeds. The firing according to any one of claims 1 to 4, comprising a tool body and a cutting edge chip brazed to a mounting seat of the tool body, wherein at least the cutting edge portion of the cutting edge chip is composed of the composite fiber body. Tying tool.

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