DK152098B - TOOL COMPONENTS, SPECIFICALLY FOR CUTTING, DRILLING AND TAKING TOOLS, AND PROCEDURES FOR MANUFACTURING THEREOF. - Google Patents

Description

DK 152098 B

The invention relates to a tool's component, especially for cutting, drilling and cutting tools, with abrasive particles of diamond or cubic boron nitride, a metallic sintering aid and empty pores.

In the disclosure of U.S. Patent No. 3,745,623, a diamond composite material is disclosed which comprises a mass of polycrystalline diamond in which substantially all diamond particles are bonded to each other and integrally bonded to a sintered carbide mass. The bonding of the diamonds to each other and the bonding of the diamond mass 10 to the carbide substrate are produced under high temperature / high pressure conditions (HT / HP technology) in the stable diamond region, thereby making the bond metal of the sintered carbide available to both masses to produce said bonding of the diamond particles and the two lots. The bonding / catalyst metal remains in both masses in the integrate composite unit thus formed.

In the specification of U.S. Patent No. 3,609,818, apparatus (reaction vessels) of a type useful for practicing the HT / HP ratios used according to the aforementioned U.S. Patent No. 3,745,623 is disclosed.

However, the diamond composite material made according to the aforementioned patents has limited utility as it is degraded thermally at temperatures above ca. 700 ° C.

US Patent No. 3,767,371, which relates to a parallel invention to that described in U.S. Patent No. 3,745,623, discloses the use of cubic boron nitride (CBN) as abrasive particles instead of diamond. In the specification of U.S. Patent No. 3,743,489, which is a parallel to U.S. Patent No. 3,767,371, an use of aluminum alloys is described to improve the bonding mechanism of the CBN composite.

30 However, also the composite materials made according to the latter two US patents have limited utility as they are thermally decomposed at temperatures above ca. 700 ° C.

The above known composite materials are therefore unsuitable for manufacturing tool components which require bonding of composite material to a support by means of a solder having a melting point near or above the heat decomposition point of the composite material or requiring molding of the composite material with a wear resistant matrix. high melting point, as is commonly used in connection with surface hardened rock drills 2

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crowns.

These deficiencies of the composite materials of the prior art, however, are remedied by the present invention, according to which tool components are provided, especially for cutting, drilling and cutting tools, which withstand exposure to much higher temperatures of up to 1200 -1300 ° C without significant thermal decomposition, cf. page 5, lines 7-19 of this specification.

This is achieved with the tool component of the type 10 initially mentioned, as it is characterized by the abrasive particles being self-bonded and constituting 70-95% by volume of the tool component that the metallic sintering aid which serves to bond the self-bonded particles is 0 , 05-3% by volume of the tool component, and that the empty pores defined by the self-bonded particles are distributed in the tool component with an interconnected structure, which pores constitute 5-30% by volume of the tool component.

In one embodiment, a layer of self-bonded abrasive particles is bonded to a base of sintered cemented carbide.

The invention also relates to a method for producing a tool component according to the invention, wherein method a). a mass of diamond particles or particles consisting of cubic boron nitride and a mass of metallic sintering aid for said particle mass is introduced into a reaction vessel; b) the reaction vessel containing contents is simultaneously subjected to temperatures in the range of 1200-2000 ° C and pressures above C) the heat supply to the reaction vessel is brought to ten! and d) the abrasive body formed during process steps a) to c) consisting of the directly bonded particles and the metallic sintering aid penetrated between the particles is removed from the reaction vessel; which method is characterized in that the metallic sintering aid which has been introduced into the body is removed from it until there is a 0.05-3% by volume of the body back in the body.

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In step b), the term "simultaneous" must indicate that the high-pressure / high-temperature conditions exist or occur simultaneously, but the term does not imply that the times for initiating or terminating the high-pressure and high-temperature conditions coincide (which may however be the case).

"Sintering aid" is used in the present context to designate materials which are catalysts for diamond as set forth below and / or which promote the sintering of CBN as set forth below. The mechanism (catalysis 10 or other), whereby the sintering aids promote the self-binding of CBN is unknown.

Thus, with the present invention there is provided a tool component comprising a compact mass consisting essentially of self-bonded abrasive particles having a network of interconnected pores distributed within the mass. The compact is produced by bonding a mass of abrasive particles to a self-bonded body using a high pressure, high temperature sintering aid. The body formed at high pressure and high temperature contains the self-bound particles and the sintering aid (e.g.

20 cobalt or cobalt alloys) which permeate the body. The permeable material is then removed e.g. by immersing the body in a bath of royal water. It has been found that removal of virtually all of the permeable material provides a compact material of abrasive particles with significantly improved resistance to thermal degradation at high temperatures.

Preferred embodiments of steps a) -d) of the above process for producing a diamond tool tool component are described in greater detail in the specification of U.S. Patent Nos. 3,745,623 and 3,609,818.

Briefly, these patents disclose the production of diamond compact materials by high pressure / high temperature treatment whereby hot, compressed diamond particles are permeated by a catalytic material by axial or radial passage of the material between the diamond particles. Through the passage, 35 catalyzed sintering of the diamond particles is achieved, leading to a far-reaching diamond / diamond bond. According to U.S. Patent Nos. 2,947,609 and 2,947,610, the catalytic material is selected from (1) a catalytic metal of unsubstituted form selected from Group VIII metals, Cr, Mn, Ta, (2) a mixture of alloys. metals 4

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of the catalytic metal (s) and one or more non-catalytic metals, (3) an alloy of at least 2 of the catalytic metal and (4) an alloy of the catalytic metal (s) and one or more non-catalytic metals. Cobalt in uncompensated or alloy form is preferred. This material forms a metal phase in the abrasive body formed by the high pressure / high temperature conditions given above in step b).

Preferred embodiments of steps a) -d) of the above process for producing a tool component of cubic boron nitride particles 10 are described in greater detail in the description to U.S. Pat.

Patent No. 3,767,371. As disclosed in and in connection with Example I of this patent, CBN compact materials (CBN = cubic boron nitride) are produced by a high pressure / high temperature process in which CBN particles are permeated by a molten sintering aid (cobalt metal) by axially passing the material between the CBN particles. . During the passage, sintering of the CNB particles is achieved, leading to extensive CBN / CBN bonding. Other materials useful as cubic boron nitride sintering aids are known from the specification of U.S. Patent No. 3,743,489, column 3, lines 6-20, and are 20 alloys of aluminum and an alloy metal selected from nickel, cobalt, manganese, iron, vanadium. and chromium. Cobalt and cobalt alloys are preferred. The sintering aid forms the metal phase indicated in step d) above.

In carrying out an embodiment of steps a) -d) according to the disclosure of US Patent Nos. 3,745,623, Nos. 3,767,371 and 3,743,489, a composite compact material is prepared by an in situ bonding of an abrasive particle layer (of diamond or CBN) to a sintered carbide carrier. The material for forming the carbide support (either a carbide forming powder or a preformed body) is the preferred source of the sintering aid. For clarification of the details of the carrier, reference is made to U.S. Patent No. 3,745,623, column 5, line 58 to column 6, line 8 and column 8, line 57 to column 9, line 9.

Another embodiment of the invention relates to the formation of a compact material consisting essentially of self-bonded abrasive particles. In this embodiment, steps a) - d) are practiced in the manner described above, except that provision of material for forming the carbide substrate for the abrasive particle layer, either in the form of a carbide casting powder or in the preformed state, is preferably omitted.

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Including the sintering aid separately, e.g. as shown and disclosed in the specification of U.S. Patent No. 3,609,818. Of course, a support of sintered carbide or other material may be brazed to the contact material after removal of the metallic phase to form a tool blank or insert.

According to the present invention, it has been found that the metal phase can be removed from the compact by acid treatment, liquid zinc extraction, electrolytic removal or similar processes, leaving a compact containing 10 substantially 100% abrasive particles in self-bonded form. Thus, the composite material has essentially no residual metal phase for catalysis of back-conversion of the bonds between the abrasive particles and / or expansion and thus breaking of the particle bonds, since these are the two mechanisms which were theoretically supposed to lead to the thermal decomposition of the known high temperature composite materials. It has been found that the composite material produced according to the invention can withstand exposure to temperatures up to 1200-1300 ° C without significant thermal decomposition.

The invention will now be described in more detail with reference to the drawing, which shows a photomicrograph of a portion of a ground surface of a diamond compact material made in accordance with the present invention.

Although the croft photograph in the drawing actually shows a diamond composite material, it might as well illustrate alternative embodiments of the invention in which the ground particles are of cubic boron nitride.

The composite material comprises diamond particles 11 which constitute between 70% to 95% by volume of the composite. (In the present context, the term "particle" is used to mean a single crystallite or fragment thereof). The separating surfaces 13 represent the self-bond or diamond / diamond bond between neighboring particles 11. The diamond crystals 11 seen in the abrasive surface of the composite material shown in the drawing are bonded in the third dimension to neighboring diamond crystals which are not visible.

A metal phase of sintering aid (not visible in the drawing) permeates the composite material in a substantially uniform manner and is believed to be encapsulated in the closed areas formed by neighboring diamond particles. This phase constitutes between approx. 0.05% by volume and 3% by volume of the composite. A network of mutual benefits 6

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bonded empty pores 15 are distributed over the composite material and bounded by the diamond particles 11 and the metal phase not shown. The pores 15 constitute between ca. 5% by volume and 30% by volume of the component.

In one embodiment, the composite is constituted by the self-bound particles alone. In another embodiment, the composite is bonded to a support (not shown), preferably of cobalt sintered tungsten carbide.

An acceptable particle size range for the diamond particles 1110 is between 1 and 1000 µm. For cubic boron nitride, the acceptable size range is between 1 and 300 µm.

The invention will be further illustrated below in the form of some embodiments.

Example I

A number of disc-shaped diamond compact blanks were prepared by 1) applying a 1.4 mm layer of fine diamond particles having a nominal size of less than 8 microns and cemented tungsten carbide of 3.2 mm in diameter and 8.8 mm in diameter (13 wt% Co, 87 20 wt% WC) in a 0.05 mm zirconium container element; 2) stacking a number of these elements in a high pressure / high temperature apparatus such as that of Figure 1 of U.S. Patent No. 3,745,623; 65 kb and the temperature to approx. 1400 ° C for 15 minutes, 4) slowly reducing the temperature and then the pressure, 5) removing the samples from the high pressure / high temperature apparatus and disintegrating the samples to provide a 0.5 mm thick diamond layer bonded to a cobalt cemented tungsten carbide layer with a thickness of 2.7 mm. The carbide layer in each compact was removed by surface grinding.

As indicated in Table I, half of the samples were excluded in hot, concentrated acid solutions to remove the metal phase and possibly other soluble non-diamond material. Two different methods were used to remove the permeable material. For a first group, designated samples A-1 to A-4, only hot 1: 1 mixture of concentrated nitric acid and hydrofluoric acid was used to treat samples A-3 and A-4. For another group, designated samples B-1 to B-4, the nitric acid / hydrofluoric acid mixture was replaced with a hot mixture of concentrated hydrochloric acid and 3: 1 (hydrochloric acid) hydrochloric acid to treat samples B-3 and B-4. It showed 7

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say that the rate of removal was significantly increased by using the latter acid solution. Samples A-3 and A-4 were acid treated over a period of 8 to 12 days. Samples B-3 and B-4 were treated between 3 and 6 days. For both methods, the dimensions of the 5 samples did not change during the acid treatment and that no peeling of the diamond material was detected. Therefore, any weight loss can be attributed to the removal of the permeable metal phase since diamond is not dissolved by the acids.

The amount of metal phase permeating these compact blanks was calculated to be approx. 8.1% by volume, or 19.8% by weight, based on density measurements of the compact prior to leaching, and of the diamond and metal starting materials for making the compact. After leaching, approx. 0.5% by volume or 0.2% by weight of the permeable material remaining. The removal of up to 90% by weight (Sample B-4) of the permeable material also indicates that most of the metal phase is located in a continuous network of pores. Scanning electron microscopic (SEM) examination of a fracture surface of a leached sample shows that a network of pores runs through the diamond layer. The holes are seen to be distributed over the layer, 20 and most have a diameter less than 1 µm. This indicates that the acid has permeated the entire diamond layer and removed the metal phase in a substantially uniform manner throughout the layer.

The shear fracture strength (TRS = transverse rupture strenght) and Young's modulus of elasticity (E) were also spliced for the diamond layers, as indicated in Table I. The strength test was performed on a three-point loading equipment. This equipment comprises two steel rollers arranged on a carrier with a third steel roll centered above it with its axis parallel to the other two rollers. The samples were centered over the lower rollers and loaded until fracture. The load of the samples 30 was measured in parallel with the tensile load using resistance bonding devices connected to a resistance voltage indicator. Samples A-1 to A-4 were prepared for the strength test by surface finishing with a diamond wheel (diamond particles of 177-250 µm). Samples B-1 to B-4 were prepared for the strength test by 35 surface finishing with a grinding machine, where a 15 µm diamond abrasive was used to produce a more flawless surface than that obtained on samples A-1 to A-4 by polishing. It is believed that the better polished surfaces, on the specimens that are finished with fine diamond material, provide higher strength.

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values resulting from the more perfect surface condition obtained, i.e., less stress concentrating defects. This is thought to explain the lower TRS values spleen for the excluded samples (A-3, A-4, B-3, B-4).

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TABLE I

Removing through- Shear fracture Elastic modulus penetrating fabric strength (TRS) (E) 2 3 2 10 Sample% density _kg / mm_ χ10 kg / mm A-1 0 111 A-2 0 101 A-3 16.1 73 A-4 16 , 2 87 15 B-1 0 129 89 B-2 0 143 92 B-3 17.0 88 78 B-4 17.9 81 80 20 Unlike the TRS test results, the E measurements (Table!) Are not affected by the porosity , since E is a measure of the intrinsic strength and stiffness of a material, and not of microtore formation. On average, the E-value was only approx. 12% lower when the penetrating metal phase was removed from the samples. This difference should be corrected for the porosity of the leached samples, since f = Mi £ ti E = Young's modulus M = Torque C = Distance to outer fiber I = Inertia moment of area 35 and M * C is unchanged, the trend I has been reduced as as a result of the effective area being reduced in relation to porosity.

If spherical cavities and random distribution are assumed to exist, then F - * t £ 'in E' I (1-x) in 9

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where x = porosity fraction and the value of E would therefore be greater 3 2 than miit. The mean value of 79 x 10 kg / mm for E for samples B-3 and 3 2 B-4 (excluded samples) is corrected to 85 x 10 kg / mm or approx. 5% 3 2 lower than the mean 90 x 10 kg / mm of E for samples B-1 and 5 B-2.

As a result, the removal of the penetrating metal phase has only very little effect on E and shows that the strength of the diamond layer is almost entirely due to diamond-diamond bonding.

The E-value of 90 x 10 kg / mm is about 10% lower than the mean o 3 2 10 value of 100 x 10 kg / mm, which can be calculated from elastic constants for diamond in the form of single crystals.

EXAMPLE II

A compact blank was prepared by a procedure similar to that of Example I for samples A-1 through A-4 except that a 1: 1 mixture of 149-177 µm and 105-125 µm diamond particles was used instead. for particles at 8 p.m.

Prior to leaching, the compact was calculated to have 99.1% diamond (96.5% by volume) and 11.9% by weight metal phase (4.5% by volume).

After leaching there is an 11.5% reduction in the total weight of the compact or, in other words, remains approx. 0.15% by weight of the metal phase (0.06% by volume) in the compact.

EXAMPLE III

Four diamond compact blanks were prepared as indicated in Example I. The carbide was ground from each compact blend. In two of the compact blanks, the penetrating metal phase was removed by acid leaching in hot 1HF: 1HNOs and 3HCI: 1HNC> 3. They were all mounted with epoxy on a 0.89 cm round tungsten carbide support. This composition was mounted in a tool container in a lathe, and swivels for abrasion resistance were then conducted. The work item was a silica sand-filled rubber rod, which is sold under the trademark "Ebonite Black Diamond". The test conditions were: surface velocity: 107-168 surface m / min. (in one heat treatment group, the maximum range was 24 surface m / min), cutting depth: 0.76 mm, cross feed: 0.13 mm / revolution and trial time: 60 minutes. After the sample, the samples were heat treated in a tube furnace in an atmosphere of flowing dry argon. The treatment temperatures were 700-1300 ° C and there were 100 ° C intervals between treatment temperatures

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Trips. The treatment time was 10 minutes at each temperature.

After each treatment, the samples for degradation were examined under a scanning electron microscope (SEM) and then mounted to test for wear except for the treatments at 1000 ° C, 1100 ° C and 1300 ° C. Both the top and bottom edges were used as cutting edges before repolishing.

The results of the wear test are listed in Table II. The samples were largely consistent throughout the sample. There was a tendency to reduce abrasion resistance when moving from the 10 untreated sample to a sample subjected to the first heat treatment at 700 ° C. The non-leached samples, samples 3 and 4, did not change until they completely failed between 800 ° C and 900 ° C. The heat treatment was found to be independent of the abrasion resistance until the diamond phase could no longer contain the enclosed metal phase and cracking occurred.

This behavior also indicates the presence of two distinct phases: the bonded diamond phase which performs the milling in the sample, and the metal phase, which is a residue from the sintering process. The leached samples, samples 1 and 2, withstand the heat treatment extremely well, even at 20 1200 ° C. At 1200 ° C, there appears to be a tendency for slight degradation of the sample, which may indicate that thermal back-conversion is initiated at the surface.

TABLE II

Heat treatment Leaked samples Non-leached samples ° C Sample 1 Sample 2 Sample 3 Sample 4 30 Untreated 150-200 120-150 150 100-120 700 150 120 120 100 800 “120 100 120 100 900 120 100 Radial cracks 1000 - 35 1100 - 1200 86-100 100-120 1300 - 11

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The test results in Table II indicate time per day. unit compacting wear in inches X 100. Tool wear was determined by measuring the width of the "flat part" of the compacting material caused by contact with the workpiece. The test results are only meaningful 5 when comparing the relative performance of the leached and the non-leached samples.

The excluded samples yield on average a higher sample value than the non-excluded samples. This may be due to the thermal degradation of the non-lubricated compact during machining with the specimens. Thus, the same degradation mechanism can occur both during the wear tests and during the heat treatments. If this is the case, when the tool tip is heated to high temperature when in contact with the workpiece, the cobalt phase expands more than the diamond phase and 15 cracks at the tip edge of the first few layers of particles. The damaged tip is thereby weakened and the machining ability is impaired. However, the leached specimens are thermally stable up to a higher working temperature and are not thermally damaged when in contact with the workpiece.

20 SEM analysis revealed that non-lubricated specimens had many different properties compared to the lubricated specimens. The metal phase began to penetrate from the surface between 700 ° C and 800 ° C when viewed under a magnification below 2000 X.

As the temperature was raised to 900 ° C, the specimens cracked radially 25 from the rounded cutting edge to the center of the specimen. The leached samples did not show such occurrence, but remained relatively unchanged until 1300 ° C. The diamond layers are clean at 1200 ° C, but at 1300 ° C, photographs magnified 20 X are blurred, and photographs magnified 1000 X show an etched surface with many exposed crystals.

This is presumably due to thermal degradation of the surface, but may also be the result of minor oxygen impurities in the argon atmosphere in the furnace.

EXAMPLE IV

Two diamond compact blanks (specimens IV-1 and IV-2) were prepared as set forth in Example I, except that the carbide carriers were not ground. An epoxy resin ("Epon 826" resin with nodic methyl anhydride and benzyldimethylamine curing agent) was cast around Sample IV-1 and cured. The surface of the diamond 12

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the layer was exposed by removing all plastic on the surface of the layer by sand treatment. Sample IV-1 was then placed in boiling SHCIrlHNO 3 for 37.15 hours. After removal from the acid, the plastic was removed from the carbide layer and visually observed. There was evidence of a weak reaction between the 5 acid and the non-exposed surfaces. However, the surface of the carbide layer did not appear to be significantly damaged by the acid. The surface of the diamond layer was then examined under a scanning electron microscope (up to a magnification of 2000 X). The surface of the diamond layer had an appearance similar to the surfaces of the diamond layer on the leached specimens of Example I. Sample IV-1 was then examined by energy scattering X-ray analysis to compare the intensities of the constituents of the metal phase with those of a compact type of the same type. had been ruled out. The results of the SEM analysis and X-ray analysis indicated that the 15 acid penetrated the diamond layer and removed a significant portion of the metal phase.

Samples IV-1 and IV-2 were then subjected to a swab test to determine the abrasion resistance, as described above in Example III. The results of the wear test (calculated, 20 as in Example III) were 120-150 for Sample IV-1 (the leached) and 100-120 for Sample IV-2 (the leached). These test results, which show the superiority of the lubricated compact, are consistent with the results obtained in Example III and support such that the removal of the metal phase in the cutting edge region improves the machining ability of the diamond compact.

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Claims (10)

A tool component, especially for cutting, drilling and cutting tools, with abrasive particles (11) of diamond or cubic boron nitride, a metallic sintering aid and empty pores (15), characterized in that the abrasive particles (11) are self-bonded and constitutes 70-95% by volume of the tool component, the metallic sintering aid which serves to bond the self-bonded particles (11) constitutes 0.05-3% by volume of the tool component and the empty pores (15) defined by the self-bound particles (11) are distributed in the tool component with an interconnected structure, which pores constitute 5-30% by volume of the tool component. Tool component according to claim 1, characterized in that the abrasive particles (11) are diamond particles and that the metallic sintering aid consists of (1) a Group VIII catalyst metal in the periodic system, chromium, manganese or tantalum or a mixture thereof or of (2) an alloy of at least two of the above catalyst metals. 20 Tool component according to claim 1 or 2, characterized in that the diamond particles (11) have a particle size ranging from 1 to 1000 µm. Tool component according to claim 1, characterized in that the particles (11) consist of cubic boron nitride and that the metallic phase, which is substantially evenly distributed in the tool component, consists of cobalt, a cobalt alloy or an alloy of aluminum with nickel. , manganese, iron, vanadium or chromium as alloy metal. The tooling component according to claim 1 or 4, characterized in that the particles (11) consist of cubic boron nitride having a particle size of 1-300 µm. Tool component according to claims 1-5, characterized in that the self-bonded particles are bonded to a base of sintered cemented carbide. A method of producing a tool component according to any one of claims 1-6, wherein process a) introduces a mass of diamond particles or particles consisting of cubic boron nitride and a mass of metallic sintering aid for said particle mass into a DK 152098 B (b) the reaction vessel containing at the same time is subjected to temperatures in the range of 1200-2000 ° C and pressure of over 40 kilobars; (c) the heat supply to the reaction vessel is stopped and the pressure is reduced; formed abrasive body consisting of the directly bonded particles and the metallic sintering aid penetrated between the particles is removed from the reaction vessel, characterized in that the metallic sintering aid introduced into the body is removed from this until a residue of 0.05-3% by volume of the body remains in the body. Process according to claim 7, characterized in that the metal is removed from the body by immersing the body in an acid, preferably royal water, nitric acid, hydrochloric acid or hydrofluoric acid. Process according to claim 7, characterized in that the metal is removed from the body by liquid zinc extraction. Process according to claim 7, characterized in that the metal is released from the body by electrolysis. 25 30 35