JPS61269928A - Composite body for wire drawing die - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composite for a composite wire drawing die.

Strong U.S. Patent No. 34074
No. 45 specifies a polycrystalline diamond wire drawing die structure. Also, U.S. Patent No. 3 by Wentorf, Jr.
The specification of No. 74t34 specifies a blade structure in which polycrystalline cubic boron nitride (CBN) is directly bonded to metal-bonded carbide.

Incidentally, a single crystal diamond die is suitable for drawing thin tungsten wire. However, 5. When the diameter of the wire exceeds about 0,002 inches (θ2θ3w'), single crystal diamond dice become large, expensive, and breakable. Therefore, the diameter is 0010 inches (θ234 (w
For drawing tungsten wire above r), metal-bonded carbide dies are generally used, despite their relatively short service life.

Commonly used diamond wire drawing die assemblies consist of natural single crystal diamond supported in a specialized sintered metal matrix. To achieve support for a single crystal diamond die, the diamond can be placed in a mounting ring, the space between the diamond and the ring can be filled with sinterable metal, and the metal can then be sintered.

Sinterable metals useful for such purposes must not violate the diamond during the sintering operation. Following such criteria automatically excludes the use of metals with high yield strength and high modulus of elasticity. This is because such metals are strong carbide formers by their nature and will of course attack the carbon source (i.e. the diamond in contact with the metal) under the high temperatures required for sintering.

As a result, due to the inherent properties of the sinterable support metal (i.e., low yield strength and low modulus of elasticity), the external surface of the single crystal diamond die has a large (approximately 10,000 psi (7
The application of compressive stresses (more than Kg/d) is prohibited. In the case of a conventional sintered metal supported diamond die, it is also possible to pre-apply a stress of about /θ0θθpsi at room temperature. However, when the wire drawing operation is performed hot, such compressive stress decreases rapidly as the operating temperature of the die increases.

Diamond is weak in tension. It would therefore be particularly advantageous if such drawbacks could be compensated for by permanently applying compressive stresses of about 1000 θ psi or more to the outer surface of the diamond.

U.S. Patent No. 2 θ7kuku! Polycrystalline diamond wire drawing dies as described in that patent also present the same problems as far as die mounting is concerned.

Alternatively to the use of a sintered metal matrix, such dies may be press-fitted into a binding ring, but the irregular outer surface of the die (as fabricated) may be ground to a shape suitable for press-fitting. Cost is an economic hindrance.

Therefore, if an improved wire drawing die structure, a die structure for drawing strong and hard metal wires such as tungsten, molybdenum, steel, etc. at high temperatures, could be obtained.
There will be many benefits to the industry.
'Now, the present invention provides such an improved wire drawing die structure. The composite die structure of the present invention, according to its simplest embodiment, is made of a crystalline material chosen from diamond, cubic boron nitride and polycrystalline mixtures thereof, and the shape and dimension of the wire It consists of a mandrel with a central through-hole serving as an element, surrounded by a metal-bonded carbide jacket. The metal-bonded carbide is directly bonded to the mandrel to strengthen it, and is also easy to form into a rotating body. According to a preferred embodiment (for drawing wire of 1,000 inches or more in diameter), at least seven high-strength metal rings surround a composite structure consisting of a polycrystalline diamond mandrel within a metal-bonded carbide jacket. A composite die construction such as a press fit is used. Following such an arrangement, the external rotational surface of the composite structure is permanently large (
It is placed under compressive stress (greater than about 10,000 psi).

The invention, its objects and advantages, will be better understood from the following description taken in conjunction with the accompanying drawings.

The tendency of diamond dies to crack in use before reaching the point where they need to be replaced due to wear and tear, especially when drawing thick (0.073 inch diameter) wire, has long been known. It has already been recognized that this type of failure is due to the lack of sufficient support for the tensile-strain sensitive diamond. However, the choice of supporting metal matrix is limited by the above criteria and, as a result, the In particular, no structure has yet been devised that can apply large compressive stress to the outer surface of single-crystal diamond during hot working.

Therefore, the features of the present invention are, first of all, that the six dies can be actually reinforced, are very strong, and can be easily molded into a rotating body that can be installed in a strong binding ring. The objective is to define an ideal support material for a die core. Such support material must be capable of accepting large compressive forces from the tying ring and transmitting these forces to the dies 6, thereby counteracting the tensile forces applied during the drawing process. Next, once the ideal support material has been selected, such support material is inserted between the six dice (polycrystalline or single crystal) and the binding ring, thereby causing large compressive stress on the outer surface of the six dice. It is necessary to devise a method to permanently add this.

Eventually, it was determined that the ideal support material was a metal-bonded carbide (also called "sintered carbide" or "cemented carbide"), and such a support material was inserted between the six dies and the binding ring. It has been found that the best way to do this is to bond the metal-bonded carbide directly to the die 6 body. In a preferred construction, the metal-bonded carbide forms a jacket having an outer surface suitably shaped to fit the inner surface of the tie ring to which the composite is to be mounted. In this way, when directly joining the six dies and the metal-bonded carbide, - under high temperature and high pressure (here, the unique interface created between them works to compensate for the difference in the coefficient of thermal expansion of the mandrel and the carbide material). This point is important both during the manufacture of composite dies and when using the dies under heated conditions.

First, in FIG. 1, a preferred structure for composite 10 is shown. The generally cylindrical die 6 body 11 has a through hole 12 of appropriate size and shape. Mandrel 11 is illustrated as a polycrystalline mass consisting of diamond crystals, cubic boron nitride crystals, or a mixture thereof;
Single crystal diamond can also be used. The jacket 13 is a mass of metal-bonded carbide bonded directly to the die 6 body 11 along a void-free interface. The interfaces are irregular and interdigitated on the scale of 7 to 700 microns, with such interlocking occurring between individual polishing side grains and portions of the metal-bonded carbide mass. Such an interfacial structure occurs in both polycrystalline and single crystal diamond.

In the latter case, microscopic etching of the diamond occurs and the etched areas are filled with metal-bonded carbide.

Next, another structure is shown in FIG.

In this case, the composite body 20 initially has an upper surface, a
Polycrystalline internal abrasive layer 2 surrounded on the bottom and sides
It consists of 1. In the finished composite shown, masses 22a, 22b and 22C are integral.

In either structure, the complex (preferably 2-
It is molded as a rotating body (with a taper of
In this way, the throat of the hole 23 is made of a strong, wear-resistant material.

Examples of suitable high temperature, high pressure apparatus for producing composites 10 and 20 include the subject matter of Hall, US Pat. No. 294t/2'lF, which is incorporated herein by reference. These are briefly shown in Figure 3.

Also shown in FIG. 3 is a loading assembly useful in practicing the present invention.

The device 30 includes a pair of sintered tungsten carbide punches 31 and 31 and an intermediate belt or die member 32 of the same material. Die member 32 has an aperture 33 within which is located a reaction vessel 34 shaped to accommodate a loading assembly as described below. Gasket-insulator assemblies 35 are included between the punch 31 and the die member 32 and between the punch 31 and the die member 32, each of which includes/pairs of thermally insulating and non-conductive pyrophyllite. It consists of members 36 and 37 and an intermediate metal gasket 38.

In the preferred embodiment, reaction vessel 34 is a hollow salt cylinder 39.
Contains. However, (a) during high temperature and high pressure work (
(b) does not transform into a much stronger and more rigid state (e.g., by phase transition or densification), and (b) substantially eliminates volumetric discontinuities at high temperatures and pressures, as seen, for example, in the case of pyrophyllite and porous alumina. The cylinder 39 can also be made of other materials (eg, talc), provided that they do not occur in a similar manner. Note that K for manufacturing the cylinder 39 is based on Strong's U.S. Pat.
The first section of! Those that meet the criteria described from line 9 to line C of the second section are useful.

Adjacent to the inside of the cylinder 39 is an electric resistance heating tube 4 made of graphite.
0 are placed concentrically. Inside the graphite heating tube 40, a cylindrical salt inner tube 41 is also installed in a circular manner. At the upper and lower ends of the liner 41,
Salt plugs 42 and 42' are fitted respectively.

End plates 43 and 43' made of conductive metal are installed at both ends of the cylinder 39, and electrical connection to the graphite heating tube 40 is established therethrough. Terminal discs 43 and 43'
Located adjacent to the conductive ring 4 are end cap assemblies 44 and 44', respectively.
It consists of a plug or disc 45 of pyrophyllite surrounded by 6.

Operating techniques for simultaneously applying high temperatures and pressures in such devices are known to those skilled in the art. Note that the above description is only about seven examples of high-temperature, high-pressure devices. That is, various other devices can be used within the scope of the present invention as long as they can generate the required temperatures and pressures.

Although not shown to scale, a loading assembly 50 fits into the space 51 of the apparatus of FIG.
Loading assembly 50 consists of a cylindrical sleeve 52 made of a shielded metal selected from zirconium, titanium, tantalum, tungsten and molybdenum. Inside the shielded metal sleeve 52 is a subassembly surrounded by a shielded metal disk 54 and a shielded metal cup 56. In the case of the arrangement shown, which is intended to produce a composite with straight through holes in a polycrystalline core,
A line of appropriate dimensions (e.g. 0070 inch diameter (θ2.
f41ws ) 57 is suitably positioned and then (for example by welding) the cup 56
It is supported jointly on the bottom of.

Around the line 57 are arranged grains 58 of a hard abrasive (diamond, cubic boron nitride or mixtures thereof), thereby forming a cold-pressed sinterable carbide forming powder (carbide powder and suitable If desired, the sleeve 59 may be comprised of a pre-sintered metal-bonded carbide, as described below.

A particularly preferred metal to use for forming through holes in a polycrystalline core is tungsten.

This is because tungsten has a high melting point and is a solid metal that can withstand deformation caused by abrasive crystal grains during the compression sintering process under high temperature and high pressure. Tungsten is also less difficult to remove later by melting or grinding. It should be noted that other materials such as molybdenum, zirconium, titanium, tantalum, rubidium, rhodium, rhenium, osmium and non-metals such as refractory carbides or even refractory oxides can be used. Such lines need not have a uniform cross-section as shown, but any shape that minimizes the effort required to form the preformed hole into the desired double taper configuration may be used. It is possible.

The remaining volume within loading assembly 50 is occupied by disks 61a and 61b made of the same material as cylinder 39 (eg, sodium chloride) and disks 62a and 62b of hexagonal boron nitride metal.

The discs 62a and 62b are connected to the disc 54 and the cup 56.
are provided to minimize the ingress of undesirable materials into the subassembly enclosed by the subassembly. Additionally, when sleeve 52, disc 54, and cup 56 are comprised of zirconium or titanium, the presence of these materials has been found to enhance sintering of the abrasive grains and bonding of the metal-bonded carbide jacket thereto.

Example / Cold pressed grade, 15-A carboloy powder (/
3 (weight) ChiCo+? 7 (weight) WC) to diameter 0
A sleeve 59 was made with a 707 inch perforation. This sleeve was placed inside a zirconium cup. In the center of the interior of the cup, as shown in Figure 3, stood a 0010 inch diameter tungsten wire welded to the bottom. 10 around the tungsten wire.
0/200 mesh diamond crystal grains are injected,
The perforations in the sinterable sleeve were thereby filled.

In addition, the sleeve 52 and the discs 54, 63a and 6
3b is also made of metal zirconium (thickness 0002 inches (θθt
/m)). Such a loading assembly was introduced into a high temperature, high pressure apparatus such as that shown in FIG. /! Temperature ahead of 0 and about evening! After applying kilobar pressure for about 40 minutes, the temperature was allowed to drop to near room temperature and then the pressure was released. The diamond-metal bonded carbide composite recovered from the device was approximately 0.
It had a diameter of 23 inches (J': cf'm) and a length of approximately 0.23 inches (J': cf'm). The tungsten wire, zirconium envelope and a portion of the metal-bonded carbide exterior were melted in a hot HF+HNO3 bath. A protective fused polyethylene coating was then applied to the surface of the composite while the tungsten wire was completely removed by continuing the corrosion operation.

In structures where diamond grains are used as the mass 58, extremely extensive diamond-to-diamond bonding is achieved. However, when CBN grains or a mixture of CBN grains and diamond grains are used, alloying aluminum atoms with at least seven elements selected from nickel, cobalt, manganese, iron, vanadium and chromium. A metal phase containing metal atoms must coexist. The amount relationship between aluminum and alloying metal is not critical and can range from approximately equal amounts to about/part (by weight) of cyfluminium to part alloying metal/theta (by weight). The amount of aluminum in the initial material can be from about 2% to about 100% (by weight) of CBN, while the amount of alloying metal can range from about 2 to about 100% (by weight) of CBN.
Get help with Chi. The amount of alloying metal remaining as a base in the coalesced CBN varies depending on the pressure and duration of the high temperature and pressure conditions. In any case, the refined CEN
The amount of aluminum and alloying metals in CBN
It is about / (weight) - or more.

The preferred grain size range is 23 for diamond grains.
0-270 mesh (US standard sieve) or CBN
The grain size is 0.7 to 70 microns. Of course, other particle sizes can also be used. That is,
The grain size of diamond grains is approximately θ/~! The particle size of CBN grains is about 0.07 to 20.00 microns.
I got it from Micron.

When diamond grains are used as the dice, the preferred initial diamond content is η (capacity). After making, the composition of the 6 dice is O~R? (capacity)%
of diamond and λ~10% (by volume) of metal binder (used for metal bonding carbides).

In any case, in order to guarantee diamond-diamond bonding, 70 (capacity) t is included in the completed die center body.
There must be more than s diamonds. If the initial diamond content is between 7θ and 90% by volume, sinterable carbide or metal powders can be mixed with the diamond.

If CBN grains are used as the six dice, what is the preferred initial CBN content? θ~ri7 (capacity>S, the remainder is occupied by the metal medium. The composition of the six completed dice is CBN, the metal medium present as various phases, and a small amount of metal bonding derived from metal bonding carbide. consisting of a drug.

To make a composite die with six diamonds, the loading assembly 5o is placed in the apparatus 3o, pressure is applied, and the system is heated. At that time, in order to sinter the carbide-metal binder mixture, approximately /3θθ~/
For example, at the same time a temperature in the range of about 3 K is used for more than about 3 minutes to ensure thermodynamically stable conditions for the diamond in the system! ! High pressures on the order of kilobars are applied to the system. At /30 ahead, the minimum pressure is about jO kilobar, and at /4tO, the minimum pressure is about!
2! Must be Kiqbar. Under the operating temperature,
Of course, as a result of the metal binder in the system being melted, a portion of it is transferred from the mass 59 into the mass 58 . Such a metal binder could serve as both a catalyst and a solvent for the growth of diamond crystals in the case of fabrication of melted polycrystalline diamonds.

In making a composite die having six CBN or CBN-diamonds, the loading assembly 50 is connected to the apparatus 30.
the system is placed inside, pressure is applied, and the system is heated. In that case, temperatures in the range of about 73θθ~/OO℃ are used for about 3 minutes or more, while at the same time ensuring thermodynamically stable conditions for the CBN in the system, e.g. High pressures of the order of tachybar are applied to the system.

At /30ji, the minimum pressure is about θ kilobar, and /Otsu0
At 0°CJ, the minimum pressure is approximately! It is required that θ kilobar. At the operating temperature, the metal binder in the mass 59 melts, so that cobalt, nickel or iron (depending on the sinterable carbide formulation) is transferred from the mass 59 to the mass 58.
and alloys with the molten aluminum alloy present or produced in the mass 58. The metal medium thus generated is C near the interface between the lumps 5B and 59.
It acts as an effective binder for the BN grains, thereby binding the CBN grains to each other and to the sintered carbide. The ab CBN grains in the mass 58 are interconnected by the presence of a metallic medium (introduced or generated in situ) and its reaction with CBN.

As a result of the direct bonding relationship created between the extremely high strength, wear-resistant mandrel and the surrounding rigid carbide support material, there is no need to insert any bonding layer between the two.

In this way, a solid support material that does not deform is placed in the die 6.
Direct contact with a body (for example mass 11 or 21) results in an extremely strong and durable composite due to the complementary properties of these materials used together.

The degree of bonding at the interface is generally such that the tensile strength of the grains on the polished side is stronger at the interface.

If carbide powder is used, it is /~! Preferably, it is a commercially available tungsten carbide compacted powder (mixture of tungsten carbide powder and cobalt powder) with a particle size of microns. If desired, all or part of the tungsten carbide can be replaced with one or both of titanium carbide and tantalum carbide. Small amounts of other carbide powders can also be used to ensure outstanding properties of the composite. Considering that nickel and iron have also been used in some cases as binders for carbides, the material providing the metallic bonding strength in the sintered compound was selected from among cobalt, nickel, iron and mixtures thereof. can be a member. However, cobalt is suitable as a metal binder.

The composition of a carbide molding powder useful in the practice of this invention may consist of about 7 to 4 tons (by weight > S) of carbide and about 1 to 4 tons (by weight) of a metal binder. Examples of such carbide molding powders include: is grade U3 carboloy (Otsu (wt) %Co + 9Q (wt)% WC) and grade !! human carboloy (/3 (wt) lC).

7 (weight)% WC). If desired,
By using the powders described above, pre-sintered carbide sleeves (FIG. 1) or discs (FIG. 2) may be produced.

In that case, such a sintered molded product is used in place of the cold-pressed molded product described above.

Of course, the composite die of the present invention has no through holes,
It can be made with a straight through hole or with a double tapered through hole. However, in either case some shaping is necessary to give the correct dimensions. If the holes are ``built-in'' in the core of the composite die, it is only necessary to pull out the wire soaked with diamond fine powder, which simplifies molding. If desired, a laser may be used to form the initial holes in the die core. If the hole in the die core becomes enlarged due to normal wear and erosion, the hole can be reshaped for drawing thicker wire.

Composites with precisely sized through-holes (e.g. Composite 1
0 and 20) are fabricated, the outer surface of the composite is precisely shaped as a body of revolution (eg, a regular cylinder or a truncated cone), based on seven of the main advantages of such structures. If properly shaped to have substantially the same center as the through-hole in the die core, such a composite can be housed within seven or more high-strength binding rings, thereby providing K 10θθθθpsi
A compressive stress of (7θ/−) or more can be uniformly applied. With proper design and construction, such compressive stresses will be permanently and uniformly transferred through the composite to the outer surface of the die 6.

The tie ring can be made of suitable materials of high strength (under the working conditions), such as superalloys, stainless steels, high strength steels, dispersion hardening alloys, reinforced metals, reinforced plastics and cemented carbides.

In the assembly shown in FIG. 5, the sintered carbide jacket of composite 70 was precisely shaped as a regular cylinder. Such a composite 70 (e.g., 030.20 inches outside diameter)
A7/m) ) is the metal ring 71 (for example, inner diameter 03
θ/finch (Zg3m)), and then the tapered outer surface of the metal ring 71 (preferably 2 to 4t
Metal ring 7 with a tapered inner surface to match %)
A subassembly of composite 70 and metal ring 71 was press fit into 2. Also, in case of rupture,
The die assembly may also be housed within the security ring 73.

In the case of a die assembly for drawing tungsten wire, for example, ring 71 is made of H-2/steel, ring 72 is made of superalloy (René 41), and ring 73 is made of stainless steel. Additionally, in the case of a die assembly for drawing soft metal wire (eg, copper wire) at low temperatures, all rings may be made of stainless steel.

The die assembly shown in FIG. 3 is easier to assemble and requires fewer parts.

In this example, the outer surface of the sintered carbide jacket of composite 80 was precisely ground as a tapered truncated cone of about 1 to 4 tons. The tapered composite was press fit into ring 81. No.! As in the case shown in the figure, a ring 82 is provided for safety, but it is the ring 81 that applies compressive stress.

It is also possible to create a die assembly in which a cylindrical composite is shrink-fitted into a tie ring. Such an assembly is useful, for example, for low temperature (about 100° C. or less) drawing of steel.

Regarding the strength of compressive stress that can be applied to composite dies
First, such an assembly is severely limited.

Of course, the through holes in the die core need not be circular. It is also important to note that the purpose of imparting a large hoop compressive stress to the diamond die is achieved, and that diamond (which is resistant to tension) actually prevents the rupture effect of the wire being drawn through the die. As long as it is a binding ring, a single crystal diamond can be used as a die instead of a polycrystalline diamond block.

Example From a cold pressed powder (?7 (wt) 1 wc + 73 (wt) % Co), about θ/tine inch (J', (S'
w) length, inner diameter of approximately 010 inches (23w) and θ
2! A thick walled sleeve with an outside diameter of inches (4Q+u+) was made. This sleeve was placed in a zirconium cup with a wall thickness of approximately 0002 inches (θ (173/vm)) that matched the dimensions of the sleeve.
The central perforation was filled by injecting and lightly tamping 7θ mesh synthetic diamond grains. Two zirconium disks, each having a diameter of about 0 inches and a thickness of 0,002 inches, were then placed on top of the diamond-filled sleeve. The entire zirconium cup and pressed powder sleeve were housed in a zirconium tube with a wall thickness of θαI inches (θθ21=m). The assembly was placed in a compressed salt holder and then inserted into a graphite heating tube as described in connection with FIG.

Approximately the pressure on the assembly! After increasing the temperature to tachybar, heating was carried out at approximately 0°C for 6θ minutes.

After cooling and subsequent pressure relief, the entire cup, sleeve and diamond were recovered as a solid cylinder. After dissolving the deposited zirconium in a HF-HNO3 mixture, the end face of the central diamond pillar was inspected by polishing one end face of the cylinder on a diamond lap. As a result, extensive diamond-diamond bonding was observed. Next, the side surface of the cylinder (metal-bonded carbide) was ground to a diameter of θJ inch (J/Otsu 2 m). On the other hand, θko02 inch (yo/
It has an inner diameter of 0.05 inch (3 to 7 m), an outer diameter of 0.0 inch (7 m), and a thickness of 0.0 inch (7 m)! A steel ring was made and then heated 4 to. The diamond-containing cylinder described above was quickly pressed into the hole of the ring, and then the whole was allowed to cool. Finally, a hole with a diameter of 0073 inches (θ3J'/w) suitable for drawing the tungsten wire was formed in the diamond pillar. Tungsten wire was drawn using the thus completed die assembly. During the wire drawing operation, the die is maintained at approximately θO℃, while
The line is approx. Preheated to 00°C.

about! After drawing a kilogram of tungsten wire, the dimensions and shape of the drawn wire revealed that the diamond section cracked due to the bursting force exerted by the wire passing through the die. Apparently, the radial compressive support provided by the mild steel ring was insufficient under such operating conditions. However, the life of the die described above was comparable to that exhibited by natural single crystal diamond dice for such conditions.

Example 3 A diamond grain and WC+Co sleeve assembly similar to that described in Example 3 was made. However, the perforation of the sleeve in this example is θ/2
! It had a diameter of inches (3/J'm). As in Example =, after encapsulating such an assembly in zirconium and applying high temperature and pressure, the cylinder is recovered and has an outer diameter o
It was ground to a 2θ die inch (i/J'w) and then pressed into a mild steel retaining ring similar to that in Example 2.

A wire drawing die was prepared to draw a tungsten wire having a diameter θ0/M inches (θj2jm) by drilling a hole in the diamond pillar according to standard drilling techniques.

Such a die was used under similar conditions as in Example 2.

After drawing approximately 700 kilograms of tungsten wire, the cylinder inside the ring became loose and the die was taken out of service for inspection. As a result, it was found that although the die was not cracked or severely worn, it was found to be unusable due to loosening within the binding ring. Still, the die exhibited more than twice the lifespan of traditional single-crystal diamond dies. The die was then reinstalled in a ring that provided greater compressive stress and re-drilled to draw a thicker wire, with satisfactory performance still obtained.

EXAMPLE As in Example 3, a composite die body consisting of polycrystalline diamond and a sintered tungsten carbide-cobalt sleeve was fabricated and had an outer diameter of 0.2 inch (0.2 inch).
r2m). The body was pressed into a hardened abrasive sleeve made of hot worked tungsten steel. This sleeve had an inner diameter of 0203 inches (i/74tm) and a length of 0.2jO inches (6,33m), and its outer surface was tapered (one end had a diameter of θQjθ inches (//4tm)). And the other end has a diameter of θkku!inch (//3u)). Such an assembly then has a thickness of 05θ inches (/, 2..7w1) and/or
60 inch (3? 1w) outer diameter (/r-/wall thickness of stainless steel safety ring θθ6.2 inch (/:jJ's
The Rene 41 ring was pressed into the tapered hole of the Rene 41 ring with a force of approximately 3θθθ pounds (1360 Kg>). As a result, the Rene 41 ring was pressed into the internal assembly with a force of approximately /20,000 psi (cf'μt/ It exerted a compressive stress of wj), thereby resisting the bursting force exerted by the wire passing through the die.The completed assembly is thus similar to that shown in Figure !.

The six diamonds are drilled and finished according to traditional techniques, with a diameter of 0.073 inches (θ33
) A die suitable for drawing tungsten wire was fabricated. After several months of use, more than 100 kg/100 kg of hot tungsten wire was drawn from such dies in a normal production process. However, the die still looked like new and continued to be used.

To this point, the dies described above have produced several times the amount of tungsten wire compared to the best traditional diamond dies used under the same operating conditions.

Example ! The outer diameter of θ34t (&//1IJ) and approximately (2
Sintered tungsten carbide with a length of 230 inches (33 m>) L, 7 (weight) IWC+#
(weight) %Co) in the center of a cylinder with a diameter of 0170 inches (
'A32m) hole was formed. The hole is 230/
, filled with 2,70 mesh of artificial diamond grains. The resulting assembly was surrounded by a 0,002 inch thick zirconium plate and then placed in a high temperature, high pressure reaction vessel as described above. A pressure of approximately 33 kilobar is applied to the loading assembly while approximately /yo!
With r! ♂Heating was carried out over a period of time. After cooling, the pressure was released and the loading assembly was recovered as a solid cylinder. The outer zirconium layer was removed with an abrasive and then both end faces of the cylinder were polished on a diamond lap. After the ends of the diamond mandrel were flattened, microscopic observations were made. The results showed that the diamond mandrel consisted of a large number of crystal grains that were tightly bonded to each other, and many diamond-diamond bonds were observed. The length of such a cylinder is 0205 inches (J
:2/m).

Next, the side surface of the cylinder was ground to have a taper of 2To, so that the larger end face had a diameter of θ &〃 inch (and 3≦U) and the smaller end face had a diameter of 0325 inch (&
−? 4m).

A ring with a thickness of 0373 inches (9J”3m) and an outside diameter of 100 inches (2i 4twi) is /?-♂
Made from stainless steel. The internal hole has a taper of =- and a diameter of 032 at the larger end.
Otsu ≦ inch (Otsu review ≦ fight).

The diamond-sintered carbide composite cylinder described above was pressed into the hole with a force of approximately υ pounds (227 kg), resulting in an assembly similar to that shown in FIG. 6, except for the safety ring. Obtained. What if I do this?
−? Approximately tit the stainless steel ring is attached to the inner composite cylinder
This results in a hoop compressive stress of oθθθpsi (2rKf/-). ) By performing the drilling and finishing of the diamond mandrel during such assembly according to traditional techniques, the diameter θg θ
A die for drawing a 3-inch (7023w) copper wire was prepared. The die was used for several months and produced over 500 pounds of copper wire with an excellent surface finish suitable for enamel insulation. Moreover, the polycrystalline friction surface also appeared to improve the lubrication of the passing wire by capturing lubricant from the lead-in wire. This die assembly continued to be used.

Example Sintered tungsten carbide (?7 (wt) 1 wc + 73 (wt)
%Co) diameter θ/2 at the center of the cylinder! An inch hole was formed. Such a cylinder is placed in a zirconium cup with a wall thickness of 0002 inches, and the hole is marked with a tag (capacity) -
Cubic boron nitride powder with a particle size of 07-10 microns (capacity) - 3007 yen mesh NiA1. Filled with powder and mixture. A zirconium disk was placed on the cylinder within the cup, which was then placed into a high temperature, high pressure reaction vessel as described above. A pressure of about 33 kbar is applied to such an assembly while about 763-(
Heating was carried out for jQ minutes at . After cooling, the pressure was released and the composite cylinder was recovered. One end face of the composite cylinder was polished on a diamond lap, thereby exposing the cubic boron nitride pillars. When examined under a 300X microscope, the intergranular bonding of the cubic boron nitride and the bonding with the sintered carbide jacket appeared to be excellent. Although not yet tested, such cylinders appear to be particularly suitable for drawing steel or tungsten wire, where the lower chemical reactivity of cubic boron nitride (compared to diamond) may be advantageous. Be expected.

Example 7 Sintered tungsten carbide (7(IL amount)%WC+73<11L amount) Chi Co having an outer diameter of θ34t(&//m) and a length of 073 inches(?,/7m)
) in the center of the cylinder with a diameter of approximately θ/tag inch (jJ41g)
hole was formed. The cylinder was placed in a 0,002-inch-walled zirconium cup, and then a layer of powdered tungsten carbide-cobalt mixture (7 (wt)% WC + 73 (wt) TiCo) was lightly tamped into the bottom of the hole. It was done. Then, a wire with a thickness of 0.070 inch C/, 7 rm) and an average diameter of 0.73 mm, suitable for wire drawing dies.
After placing an inch (3.3 m) of natural single-crystal diamond onto it, the powdered tungsten carbide-cobalt mixture is again injected around and on top of the diamond, and then pressed into place using a small hand press. /θ
Compressed at an average pressure of 000 psi (7 Kg/-). The loading assembly thus obtained has a thickness of 000
It was surrounded by a 2 inch zirconium plate and then placed into a high temperature, high pressure reactor vessel as described above. Approximately to the loading assembly! While a pressure of tachybar is applied, approx.
Heating was carried out at 1° C. for about 7 hours.

After cooling to 30°C, the pressure was released and the composite cylinder was recovered. Due to the fine jet of abrasive grains,
The deposited zirconium and the sintered carbide covering the upper and lower surfaces of the single crystal diamond were removed. The partially exposed diamond appeared clear and intact. However, the surface was somewhat marbled, indicating that the surface had been etched by a slight reaction with the surrounding metal. Measurements of the thickness of the buried diamond revealed that the amount of diamond lost was negligible.

The sides of such a composite cylinder were ground to have a 2% taper, so that the larger end face had a diameter of 0, . 2j-2j
inches (J, Q/Qm) and the smaller end face has a diameter θ2
3-0 inches (g, 36 m). Such a tapered cylinder has a thickness of 0372 inches (7', 92N11) and θ? ? It was pressed into a correspondingly tapered hole in a Schilling ring having an outside diameter of inches (22,3ysx). Additionally, the Schilling ring was fitted with a protrusion within a stainless steel security ring with an outside diameter of 0.00 inches. Tapered cylinder inside Rene 41 ring]
A force of approximately /700 lbs <77/9) was used in pressing the cylinder, and the compressive stress thereby exerted on the cylinder was estimated to be approximately /20θ0θpsi (cf'4tKr/J). The assembly thus obtained was similar to that shown in FIG.

The finished assembly, like other assemblies with similar construction, has a diameter of 0007 after drilling and finishing the holes.
It can be used to draw ~0072 inch (0/?iuz~θ3θN11) tungsten wire.

[Brief explanation of the drawing]

FIG. 7 is a cross-sectional view of a composite wire drawing die consisting of six generally cylindrical polycrystalline bodies with double-tapered through holes and a metal-bonded carbide jacket directly bonded thereto; FIG. The top, bottom, and sides of the layer are surrounded by an integral metal-bonded carbide layer directly bonded to it, and at least the throat of the double-tapered through hole serves to shape and dimension the wire. Cross-sectional view of a rotating composite die defined by crystalline layers, 3rd
The figure is a cross-sectional view (partially an elevational view) showing an example of the high-temperature and high-pressure apparatus for manufacturing composite dies of the present invention, and Figure 3 is a cross-sectional view of the loading assembly to be introduced into the working space of the apparatus shown in Figure 3. , and FIGS. 5 and 6 are cross-sectional views of an embodiment of a composite die-tying ring assembly. In the figure, 11 is six polycrystalline bodies, 12 is a through hole, 13 is a metal bonded carbide jacket, 21 is a polycrystalline layer, 22a to 22c are metal bonded carbide layers, and 23 is a through hole. Patent Applicant: General Electric Company

Claims (1)

[Claims] (a) an inner mass consisting essentially of polycrystalline diamond and having or capable of being provided with through holes; (b) supporting said inner mass symmetrically and under compression; at least one outer metal-bonded metal carbide mass bonded to and surrounding the inner mass, and the metal-bonded metal carbide mass has a mass of about 7
A composite body for a wire drawing die made of a sintered body containing 5 to 94% by weight of metal carbide.