JP2000246645A - Polycrystalline polishing material molding improved in corrosion resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a support polycrystalline diamond and polycrystalline cubic boron nitride cutting tool improved in corrosion resistance. SOLUTION: This support polishing material grain molding comprises a cobalt sintered carbide support body integrally jointed to a polishing material grain layer containing self-bonding diamond grains or CBN grains. A cobalt component in the support molding is in the form of a nickel-cobalt alloy, and the quantity of nickel is to such an extent as in a face-centered cubic(FCC) phase or ε-phase. To manufacture a cutting tool, Ni metal is infiltrated into a sintered WC support body and/or a polycrystalline layer jointed thereto. As examples of such jointing, there are a method of forming a support polycrystalline molding under a condition of HP/HT (HP/HT) and a method of brazing a polycrystalline molding to a support body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tool incorporating an abrasive particle compact, and more particularly to a tool having corrosion resistance, heat resistance, wear resistance, stress corrosion resistance and high-temperature relaxation. The present invention relates to a tool having improved properties including the following. Such tools have particular utility, for example, in drilling, wire drawing and machining applications.

[0002]

2. Description of the Related Art Compacts are generally characterized as an integrally bonded structure consisting of a sintered polycrystalline mass of abrasive particles such as diamond or cubic boron nitride (CBN). Such a molded body can be bound without using a bonding base material or a second phase,
It is generally preferred to use a suitable bonding matrix, as described in U.S. Pat. Metals such as copper or their alloys or mixtures. The bonding matrix, formulated at about 5-35% by volume, may further include a recrystallization or growth catalyst, such as aluminum for CBN or cobalt for diamond.

[0003] In many applications, it is preferred to join the molded body to a substrate to support the molded body to form a laminated structure or a supported molded body. Typically, the substrate is prepared as a sintered metal carbide (i.e., a metal carbide cemented carbide), for example,
Consisting of tungsten carbide, titanium carbide or tantalum carbide particles or a mixture thereof bonded together with a metal binder such as about 6 to about 25% by weight of cobalt, nickel, iron or a mixture or alloy thereof. Moldings and supporting moldings are described, for example, in US Pat. No. 3,381,428.
No. 3,852,078 and 3,876,751 and the like, they are used in various applications as parts or blanks for cutting tools and dressing tools, drill bits, or worn parts or surfaces.

The basic high-temperature high-pressure (H) method for producing polycrystalline and support moldings of the type associated with the present invention
P / HT) method is disclosed in U.S. Pat.
No. 941241, No. 2941248, No. 3609
No. 818, No. 3767371, No. 4289503
No. 4,673,414 and No. 4,954,139, diamonds in a protective shielding enclosure located in the reaction cell of an HT / HP apparatus of the type detailed in US Pat.
It comprises placing a green layer of crystalline abrasive particles, such as CBN or a mixture thereof. If the sintering of diamond particles is intended, the enclosure may include a metal catalyst along with the abrasive particles, as well as a preform of sintered metal carbide to support the abrasive particles as a support compact. The reaction cell contents are then subjected to selected processing conditions sufficient to cause intercrystalline bonding of adjacent abrasive particles and, if desired, bonding of the sintered particles to the sintered metal carbide support. Such processing conditions generally include 10
At temperatures above 00 ° C and pressures above 20 kbar, approx.
Imposed for ~ 120 minutes.

[0005] With respect to sintering of a polycrystalline diamond (PCD) compact or support compact, the metal catalyst may be placed in a pre-compacted state adjacent to the crystalline abrasive particles. For example, the metal catalyst may be formed as an annular body and contain therein a columnar body of crystalline abrasive particles, or the metal catalyst may be formed in a disk shape and a crystalline abrasive layer formed above or below the disk. May be arranged. Alternatively, a metal catalyst, also known as a solvent, may be prepared in powdered form and mixed with the crystalline abrasive particles, or may be cold-pressed as a sintered metal carbide powder or carbide molding powder. May be
In the latter case, the cementing agent becomes a catalyst or solvent for the recrystallization or growth of diamond. Typically, the metal catalyst is selected from cobalt, iron, nickel or alloys or mixtures thereof, but other metals such as ruthenium, rhodium, palladium, chromium, manganese, tantalum, copper and their alloys and mixtures may also be used. .

[0006] Under the specific HT / HP conditions described above, the metal catalyst, in whatever form it is prepared, can penetrate or "sweep" into the abrasive layer by diffusion or capillary action.
p) "and become available as a catalyst or solvent for recrystallization or intercrystal growth. The HT / HP conditions operate in a thermodynamic diamond stable region above the equilibrium line between the diamond and graphite phases, resulting in the compaction of the abrasive particles, which results in the compression of each crystal lattice between adjacent grains. Partially characterized by shared diamond intercrystalline bonding. Preferably, the diamond concentration in the compact or in the polished cable of the support compact is at least about 70% by volume.
Methods for producing a diamond compact and a support compact are described in U.S. Pat. Nos. 3,142,746, 3,745,623, 3,609,818, 3,850,591 and 439.
No. 4170, No. 4403015, No. 479732
No. 6 and No. 4,954,139.

[0007] Regarding sintering of a polycrystalline CBN (PCBN) compact and a support compact, such a compact and a support compact are produced according to a method for producing a diamond compact. However, in the production of the CBN compact by the above-mentioned “sweep” method, the metal that penetrates the crystalline CBN layer does not necessarily need to be a catalyst or a solvent for recrystallization of CBN. Thus, while cobalt is not a catalyst or solvent for CBN recrystallization, cobalt sintered tungsten carbide (co
balt-cemented tungsten carbide)
The substrate can be joined to a polycrystalline CBN compact by infiltrating cobalt into the gaps of the N layer. The cobalt in the gaps rather functions as a binder between the polycrystalline CBN compact and the sintered tungsten carbide substrate.

[0008] As in the case of diamond, the H
The T / HP sintering process is performed under conditions where CBN is the thermodynamically stable phase. Under such conditions, the adjacent CB
It is presumed that intercrystalline bonding between N crystal grains is also achieved. The CBN concentration in such shaped bodies or in the polished cables of the supported shaped bodies is preferably at least about 50% by volume. The methods for producing CBN compacts and support compacts are described in U.S. Pat. Nos. 2,947,617, 3,136,615, 3,233,988, 3,743,489, and 374.
No. 5623, No. 3831428, No. 391821
No. 9, No. 4,188,194, No. 4,289,503,
Nos. 4,673,414, 4,797,326 and 4,954,139. US Patent No. 376
No. 7371 describes a C containing about 70% by volume or more of CBN and about 30% by volume or less of a binder metal (such as cobalt).
A specific example of a BN compact is disclosed.

Up to now, Packer (US Pat.
679994) is PCD or P under HP / HT conditions.
It has been proposed to produce a woodworking cutting tool consisting of a WC substrate bonded to a CBN layer. The second phase or catalytic phase of Co includes an alloy metal selected from Ni, Al, Si, Ti, Mo and Cr, and a high melting point material selected from titanium carbonitride and aluminum titanium carbonitride. . The alloy metal is described as delaying the transformation of Co from a hexagonal close-packed (HCP) phase or ε phase to a face-centered cubic (FCC) phase or α-phase. Such transformations at elevated temperatures cause microcracks, leading to product degradation. Packe
The maximum amount of alloy metal tested in the r example was 5%.

While Packer's cutting tools may be excellent for woodworking, the presence of ε-phase Co in high performance applications of PCD and PCBN cutting tools is chemically unstable, especially at high temperatures (eg, (Temperature of 410 to 440 ° C.). Thus, there is a need in the art to provide supported PCD and PCBN cutting tools with improved corrosion resistance.

[0011]

SUMMARY OF THE INVENTION The supported abrasive particle compact of the present invention comprises a cobalt sintered carbide support integrally bonded to an abrasive particle layer of self-bonded diamond particles or CBN particles. The cobalt component in the support compact is in the form of a nickel-cobalt alloy, the amount of nickel being such that the cobalt is present in the face-centered cubic (FCC) phase, ie the α phase.

[0012] The cutting tool of the present invention comprises a sintered WC substrate and / or
Alternatively, it can be manufactured by infiltrating Ni metal into a polycrystalline layer bonded thereto. Joining methods include HP / HT molding of the supporting polycrystalline body and brazing of the polycrystalline body to the supporting body.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS For a full understanding of the nature and objects of the present invention, reference should be had to the following detailed description taken in conjunction with the accompanying drawings.

Since the ε phase Co has less stacking faults than the HCP phase, that is, the α phase, it is chemically stable and has high corrosion resistance. Furthermore, the FCC structure of the base material with increased Ni content is stable over a wide temperature range, and the Ni-Co alloy has a HCP
It is difficult to return to the phase. Thus, the cutting tool of the present invention has excellent thermal stability due to the presence of the Ni alloy metal. This means that an effective amount of Ni can be transferred to a PCD, PCBN or Co in a WC support.
This can be said when alloyed. The effective amount of Ni is Ni
In the range of about 5 to 50% by weight of the Co component to be alloyed. Other metals that function similarly to Ni in this application include, for example, Pd, Pt, V, Cr, Nb, Mo, and Ta.
There is.

Ni can be added to C by any means convenient to the manufacturer.
alloyable with o. For example, PCD under HP / HT conditions
Alternatively, by pressurizing PCBN together with Ni-Co sintered carbide, Ni-Co can permeate the polycrystalline layer to obtain a dense sintered PCD or PCBN blank. Alternatively, in a Co-sintered WC support and / or in a regular PCD
Alternatively, Ni can be diffused into the abrasive particle layer of the PCBN layer. In addition, Ni can be diffused from the Ni sheet into the WC support or from the Ni brick into the Co-penetrated cutting tool previously manufactured under HP / HT conditions. As shown in the examples, such infiltration can also occur from braze alloys used to braze WCs.
Thus, any means readily available to the manufacturer for alloying an effective amount of Ni with Co can be used in accordance with the principles of the present invention.

[0016] The polycrystalline layer is preferably polycrystalline diamond (PCD). Other materials within the scope of the present invention include synthetic diamond, natural diamond, cubic boron nitride (CBN), wurtzite boron nitride, mixtures thereof, and similar materials. The sintered metal carbide substrate is of a conventional composition and may be a IVB, VB or
Examples include carbides of Group VIB metals, which are sintered under pressure in the presence of a binder made of cobalt, nickel, iron or an alloy thereof. The preferred metal carbide is tungsten carbide.

[0017] The surface shape of the diamond layer may be conical, reduced or increased diameter, chisel or non-axisymmetric. Generally, all forms of PCD and PCBN inserts used in drilling, machining and wire drawing applications are
It can be improved by the addition of i-alloy metal, due to the added thermal stability and corrosion resistance.

Further, in general, the interface between the carbide layer and the diamond layer may have any shape such as a dome shape, a hemispherical shape, a reduced diameter shape, a flat shape, and a conical shape. The boundary surface may be a smooth surface, a sawtooth surface, or the like. However, an irregular boundary surface is often preferred because the bondability between the diamond layer and the carbide substrate is improved particularly in sintering the carbide substrate and forming the diamond layer.

Supporting PCD and CBN compacts have been widely used in cutting and dressing tools, drill bits, and similar applications where the hardness and wear characteristics of such compacts are exploited. In particular, such compacts include tungsten, copper, iron,
Metal materials such as molybdenum and stainless steel have been incorporated into dies for drawing wires into wires. Typically, these drawing dies are surrounded and joined by a generally annular outer metal carbide support. Holes and other openings are provided so as to penetrate the molded body along the axial center line, through which the metal material is drawn and drawn into a wire product having a reduced diameter. Such general types of wire drawing dies and methods for manufacturing the same are disclosed in U.S. Pat. Nos. 3,831,428, 4,016,736, 4,129,052, 4,144,739, and 43.
No. 03442, No. 4370149, No. 43737
No. 00, No. 4,534,934, No. 4,828,611
No. 4,872,333 and No. 5,033,334.

[0020] With regard to the production of drawing dies in connection with the present invention, various methods may be used, but US Pat.
HP / HT sintering methods such as those described in US Pat. Nos. 31,428 and 4,534,934 are considered to be preferred. In a preferred HP / HT sintering method, a layer of CBN or PCD particles is swept with a catalyst or binder metal, such as cobalt, generally similar to the manufacture of a support compact. In the wire drawing die manufacturing process, the above particles are loaded into a surrounding metal carbide annular support. Under the processing conditions defined above, metal penetrates radially and / or axially into the interstices of the crystalline particle layer from the support and optionally the disks arranged axially. Inside the particle layer, the infiltrating metal forms an independent binder phase and produces significant intercrystalline bonding, at least with regard to PCD. The metal further joins the sintered compact to the support to form an integral structure. The quoted holes can be provided in the sintered compact by laser drilling or other machining techniques as a finishing step. Alternatively,
The holes may be formed in advance by disposing a wire in the particle layer in the axial direction and dissolving the wire in a suitable acid or other solvent after the sintering of the particle layer or removing the wire by a machining technique.

For a general description of the support molding, see US Pat.
As detailed in 797326, the bonding of the support to the polycrystalline abrasive layer involves physical elements in addition to chemical elements, and these elements are comprised of the constituent materials of each layer. It is presumed that the interaction occurs at the joint surface. The physical element of the bond appears to result from the relatively low coefficient of thermal expansion (CTE) of the polycrystalline abrasive layer compared to the sintered metal carbide support layer. That is, when the support compact is cooled from HT / HP processing conditions to ambient conditions, the support layer retains the residual tensile stress and therefore applies a radial compressive load to the polycrystalline compact supported thereon. That has been observed. Such loads keep the polycrystalline compact in a generally compressed state, thereby improving the fracture toughness, impact strength and shear strength of the laminate. In the drawing die configuration, it has been observed that the support ring generally advantageously exerts a radial and axial compressive force on the central polycrystalline core.

Further, in the commercial production of a general support molding, the product or blank recovered from the reaction cell of the HT / HP apparatus is cut by electric discharge machining or laser machining, milling, and in particular, adhesion and shielding from the outer surface of the molding. Various finishing operations are typically performed, including grinding to remove metal. Such finishing operations are also used to machine the compact into a shape, such as a cylinder, that satisfies product specifications for diamond or CBN polished cable thickness and / or carbide support thickness. Particularly with respect to drawing dies, it is common to braze the dies to a receiving ring or other support assembly before use.

While the present invention has been described and illustrated with reference to preferred embodiments, it will be obvious to one skilled in the art that the invention is not so limited. It is therefore intended that the appended claims cover any such modifications as fall within the spirit and scope of the invention. The documents cited herein are hereby incorporated by reference.

[0024]

EXAMPLES Example 1 WC of a 19 mm cylindrical PCD support molding cutter (1 mm diamond table and 8 mm WC support)
WC-C using disc-shaped Ni-based brazing material for Co support
o Abrasive blanks were prepared by brazing the support extensions. Nickel diffused into the support from the disc-shaped brazing material and alloyed with the Co present. These blanks are examples of the present invention.

The brazing tool thus produced was immersed in water at 21 ° C. (room temperature) for about 15 minutes together with a similar tool which had not been brazed with a disc-shaped Ni-containing brazing material, taken out and dried. FIG. 1 shows the degree of corrosion of the WC-Co support. The brazing tool manufactured according to the invention of FIG. 2 shows no signs of corrosion. These results demonstrate the effect of the present invention.

Example 2 FIG. 3 is a photomicrograph of another brazing tool, showing Ni--Cr
The region near the brazing line of the Pd brazing alloy is shown. This tool was also immersed in water at room temperature (21 ° C.) for about 15 minutes. Thereafter, observation was performed under a microscope as shown in FIG. WC
The support was corroded except for the layer about 3-4 microns above the brazing line.

FIG. 5 is a schematic side view of the brazing tool. As shown, the diamond compact 18 is joined to the upper carbide compact 14, and the upper carbide compact 14 is brazed to the lower carbide compact 16 via the brazing material layer 12. The portion surrounded by the circle 10 was analyzed on the upper carbide compact 14 using an EDS (energy dispersive spectrometer) microprobe (detection limit: 0.01% for all elements and 1 micron resolution). The results are shown as a graph in FIG. 6, which shows the position where the EDS analysis was performed. The obtained composition distributions are shown in Tables 1 and 2 below.

[0028]

[Table 1]

[0029]

[Table 2]

These results demonstrate that the uncorroded WC region is a region containing Ni. In this region, Ni diffused from the brazing material layer into the WC, which helped to improve the corrosion resistance of the WC.

[Brief description of the drawings]

FIG. 1 is a micrograph (75) showing the corrosion that occurred when a WC support was immersed in water at 21 ° C. (room temperature) for 15 minutes.
X).

FIG. 2 is a photomicrograph (75 ×) showing that no signs of corrosion are observed when the WC support of the present invention is immersed in water at 21 ° C. (room temperature) for 15 minutes.

FIG. 3 is a photomicrograph of a brazing tool showing a region near a brazing line of a Ni—Cr—Pd brazing alloy.

4 is a photomicrograph of the brazing tool of FIG. 3 after immersion in water at 21 ° C. (room temperature) for 15 minutes.

FIG. 5 is a side view of a diamond compact joined to a WC sandwich in which two WC compacts are brazed together.

FIG. 6: Composition distribution of the brazing tool of FIG. 5 by EDS analysis (energy dispersive spectrometer, detection limit 0.01% for all elements and 1 micron resolution).

[Explanation of symbols]

 12 brazing material layer 14 upper sintered metal carbide compact 16 lower sintered metal carbide compact 18 polycrystalline diamond compact

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Henry Samuel Malek United States, Ohio, Worthington, Oakbourne Drive, No. 1475 (72) Inventor Eoin M. Jessing Trail, # 424

Claims (20)

[Claims] A sintered cobalt carbide support having improved corrosion resistance, wherein the cobalt component in the support is Ni,
In the form of an alloy with one or more metals selected from the group consisting of Pd, Pt, V, Cr, Nb, Mo and Ta, wherein the amount of said metals is such that cobalt is present in the face-centered cubic (FCC) phase A carbide support. 2. The carbide support of claim 1, wherein the amount of said metal is in the range of about 5 to 50% by weight of said alloy. 3. The carbide support according to claim 1, wherein said metal is Ni. 4. The carbide support according to claim 2, wherein said metal is Ni. 5. A support abrasive particle compact comprising a cobalt sintered carbide support integrally joined to an abrasive particle layer of self-bonded diamond particles or cubic boron nitride (CBN) particles, wherein the cobalt in the support compact is A supported abrasive particle compact, wherein the component is in the form of a nickel-cobalt alloy and the amount of nickel is improved such that cobalt is present in the face-centered cubic (FCC) phase. 6. The method according to claim 1, wherein the amount of nickel is about 5 to 5% of the alloy.
The support molding according to claim 5, which is in a range of 0% by weight. 7. The support molding according to claim 5, wherein the abrasive particle molding comprises a polycrystalline diamond (PCD) molding. 8. The support molding according to claim 5, wherein the abrasive particle molding comprises a polycrystalline cubic boron nitride (PCBN) molding. 9. The method according to claim 1, wherein the carbide support is tungsten carbide.
6. The support compact of claim 5, which is one or more of a titanium carbide or tantalum carbide support. 10. The support molding according to claim 5, which is formed as a columnar molding. 11. The support molding according to claim 5, formed as an annular drawing die. 12. The support body according to claim 5, formed as a drill bit. 13. A method for producing a supported abrasive particle compact comprising a cobalt sintered carbide support integrally joined to an abrasive particle layer of self-bonded diamond particles or cubic boron nitride (CBN) particles. A method in which the cobalt component therein is alloyed with nickel, and the amount of nickel is such that cobalt is present in the face-centered cubic (FCC) phase. 14. The alloy of claim 1, wherein the amount of nickel alloying with cobalt is in the range of about 5 to 50% by weight of said alloy.
3. The method according to 3. 15. The method of claim 13, wherein the abrasive particle compact comprises a polycrystalline diamond (PCD) compact. 16. The abrasive particle compact comprises a polycrystalline cubic boron nitride (PCBN) compact.
The described method. 17. The method of claim 13, wherein said carbide support is a support comprising one or more of tungsten carbide, titanium carbide and tantalum carbide. 18. The support molding according to claim 5, wherein the support molding is formed as a cylindrical molding. 19. The method of claim 13, wherein said support compact is formed as an annular drawing die. 20. The method according to claim 13, wherein the support compact is formed as a drill bit.