FI65935C - TEMPERATURBESTAENDIG SLIPKROPP OCH FOERFARANDE FOER FRAMSTAELLNING DAERAV - Google Patents

Description

65935 way, there are also limited uses. Such a body also undergoes thermal deterioration or destruction at temperatures above 700 ° C. This precludes its use in applications that require (1) bonding the extrudate to a support or substrate with a brazing material having a melting point near or above the thermal deterioration point of the extrudate, or (2) molding or molding the extrudate into a high melting point durable, as commonly used in surface-set drill bits.

According to the present invention, the tool component comprises: (a) self-bonded particles selected from the group consisting of diamond and cubic boron nitride, wherein the particles comprise about 70-95% by volume of the component, and (b) 0.05-3% by volume of a metal phase comprising a sintering aid used to assist in the binding of the self-bonded particles; and (c) a network of interconnected, empty pores distributed throughout the component and defined or formed and limited by the particles, the pores forming about 5- 30% by volume of the component.

According to the present invention, there is provided a component for a machine tool comprising a compact body consisting essentially of self-bonding abrasive tool particles and having a network of pores distributed in the body with the pores in contact with each other. The compressed article is made by bonding a mass of abrasive gap particles into a self-bonding body using a sintering aid under high pressure and high temperature (HP / HT). The body, which is produced at high pressure and high temperature, comprises self - bonding particles with a sintering aid (e.g.

3 65935 cobalt or cobalt alloys) impregnated throughout the body. The absorbed material is then removed, for example, by immersing the body in a royal water bath. It has been found that removing substantially the entire amount of absorbed material provides an abrasive particle compression body with substantially improved resistance to thermal deterioration or destruction at high temperatures.

According to another embodiment, a composite extrudate body is similarly made of a layer of substantially self-bonded abrasive particles and a substrate (preferably a carbide, Cemented carbide) bonded to the layer of abrasive particles.

The accompanying drawing shows a photomicrograph of a part of the ground surface of a diamond die made according to the invention.

Figure 1 shows a diamond extrudate, but the image also provides a description of alternative embodiments of the invention in which the abrasive particles are formed of cubic boron nitride (CBN).

The extrudate comprises diamond particles 11, which make up 70-95% of the volume of the extrudate. (The term particle is used herein to denote a single crystallite or fragment thereof). The interfaces 13 are examples of a self-bond or a diamond-to-diamond bond j between closely spaced particles 11. The same diamond S crystals 11 shown on the ground surface I of the extrudate in Fig. 1 are bonded to adjacent diamond crystals (not shown in the figure) in a third dimension or direction. The metallic phase of the sintering aid (not shown) is absorbed substantially uniformly throughout the extrudate and is assumed to be encapsulated in closed areas formed by adjacent diamond particles. This phase comprises 0.05-3% of the volume of the extrudate 6 5 9 3 5. The network of interconnected, empty pores 15 is distributed throughout the extrudate and is bounded by diamond particles 11 and a metal phase (not shown). The pores 15 make up 5-30% by volume of the components.

According to one embodiment, the extrudate consists only of self-bonded particles. According to another embodiment, the extrudate is bonded to a substrate (not shown), which preferably consists of cobalt-bonded tungsten carbide.

The acceptable particle size range for diamond particles 11 is between 1-100y> im. CMB must have an acceptable size range of 1 -300yXm.

In general, a preferred embodiment of a method of making a tool component having the features of the invention comprises the steps of: (a) a mass of abrasive particles comprising diamond or CBN and a mass of material acting as a sintering aid for the abrasive particle reactor mass in question; or inside the filling unit, (b) the chamber and its contents are simultaneously subjected to a temperature in the range of 1200-2000 ° C and a pressure of more than 40 kilobars, (c) the supply of heat to the chamber is stopped, (d) the pressure applied to the chamber is removed; made in steps (a) to (d) and formed in self-bonded form from metal phase particles comprising a sintering aid impregnated into the entire abrasive article body, and (f) substantially all of the metal phase impregnated into the body is removed so that this phase formsabout 0.05-3% by volume of the component.

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The term "simultaneously" in step (b) above means that the high pressure and the high temperature are applied simultaneously, but does not require that the times for starting or stopping the high pressure j and the high temperature be met. together (although in many cases this is the case).

The term "sintering aid" is used according to the invention to denote a material consisting of a catalyst for a diamond as defined below, and / or a material which promotes the sintering of CBN, as described above. in the following. The mechanism (catalytic or other type) by which the sintering aid promotes CBN self-binding is not known.

Preferred embodiments of the steps involved in the method described above for making a tool component from diamond particles are described in more detail in U.S. Patent Nos. 3,745,623 and 3,609B10.

f It is quite generally true, as disclosed in these patents, that diamond moldings are made in a high pressure, high temperature process in which hot, compressed diamond particles are impregnated with a catalytic material by axial or radial sweep of the material. During the scan, catalyzed sintering of the diamond particles is obtained, which involves a thorough diamond-to-diamond bond. As disclosed in U.S. Patent Nos. 2,947,609 and 2,947,610, a catalytically active material is selected from the group consisting of (1) a catalytic metal in elemental form selected from the group consisting of Group VIII, Cr, Mn, Ta, (2) a catalytically active material. alloys of metal or active metals and non-catalytic alloys of non-catalytic metal or non-catalytic metals, 6 65935 (3) mixtures of at least two of these catalytic metals, and (4) alloys of catalytic metal or non-catalytic metals or non-catalytic metals or non-catalytic of an alloy of metals.

Cobalt in elemental form and alloy form must be considered good. This material forms a metal phase in the abrasive body formed at high pressure and high temperature, as shown in step (e) above.

Preferred embodiments of steps (a) to (e) of the above-described process for making tool components of cubic boron nitride are described in more detail in U.S. Patent No. 3,767,371. by a process in which particles of cubic boron nitride are impregnated with molten sintering aid material 11a (cobalt metal) by axial scanning of the material through cubic boron nitride particles. During the screening, sintering of the cubic boron nitride particles takes place and a thorough binding of the cubic boron nitride to the cubic boron nitride is obtained. Other materials that serve as sintering aids for cubic boron nitride are described in U.S. Patent 3,743,489, column 3, lines 6-20, and consist of alloys of aluminum and an alloy-chimeric material selected from the group consisting of nickel, cobalt, manganese, iron, vanadium and chromium. Cobalt and cobalt alloys are considered the best. The sintering aid forms the metal phase shown in step (e) above.

In the practice of steps (a) to (e), according to U.S. Patent Nos. 3,745,623, 3,767,371 and 3,743,489, a composite extrudate is prepared by in situ bonding a layer of abrasive particles (diamond 7,65935 or cubic boron nitride} to a hard metal strip (sintered carbide). The material for making the carbide substrate (either from the carbide-forming powder or the preformed body) is the preferred starting material for the sintering aid, and reference may be made to U.S. Patent No. 3,745,623, column 5, lines 58 to column 6, line 8, and column 8, lines 57. column 9, lines 9, which show examples of details with respect to the material.

Another embodiment of the invention is the production of a press body consisting essentially of self-bonded abrasive particles. According to this embodiment, steps (a) to (e) are performed as described above, with the exception that the provision of a material for forming a carbide substrate for the abrasive particle layer is preferably omitted, either as a carbide-forming powder or in a preformed state. When applied, a sintering aid is added separately, for example as described and disclosed in U.S. Patent No. 3,609,818. Of course, a substrate of carbide or other material can be brazed to the die after removal of metal stasis (step f) to make a tool blank or insert.

According to the invention, it has been found that the metal phase can be removed from the extrudate by acid treatment, extraction with liquid zinc, electrolytic thinning or similar methods, leaving a extrudate consisting mainly of abrasive particles in a 100% self-bonding form. The extrudate thus does not contain substantially any remaining metal phase that can catalyze the re-modification and / or expansion of the abrasive particle bond and thus break the particle bonds, which are the two mechanisms that can be expected to cause deterioration or destruction of previously known extrudates at high temperature. It has been found that θ 65935 moldings made according to the invention can withstand the effects of temperatures as low as 1200-1300 ° C without substantial thermal deterioration or destruction.

Example

Several plate-shaped diamond extrudates were made by 1) attaching a 1.4 mm thick layer of fine diamond particles nominally smaller than B / * m and a sintered tungsten carbide part having a thickness of 3.2 mm and a diameter of 8.8 mm (13 weight percent Co. 87 weight percent WC) in a 0.05 mm thick zirconium tank unit, 2) a number of these units were stacked in a high pressure and high temperature device as shown in Figure 1 in a container according to U.S. Patent 3,745,623, 3) pressure was added to about 65 kb and temperature 1400 ° C over a period of 15 minutes, 4) slowly lowering the temperature and then the pressure, 5) removing the test pieces from the high - pressure and high - temperature apparatus and grinding the test pieces so as to obtain 0.5 mm thick extrudates; bonded to cobalt-bonded tungsten carbide having a thickness of 2.7 mm. the carbide layer in each extrudate was removed by surface grinding.

As shown in Table I, half of the experiments were soaked in hot concentrated acid solutions to remove the metal phase and any other soluble non-diamond materials. Two different methods are used to remove the absorbed material. For the first group, labeled Sample A-1 and A-4, only concentrated 1: 1 nitric acid and -fluoric acid are used to treat Samples A-3 and A-4. For the second group, labeled Samples B-1 to B-4, nitric acid hydrofluoric acid is replaced with hot 3: 1 concentrated hydrochloric acid nitric acid (royal water) to treat Samples B-3 and B-4.

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It turned out that the rate of excretion was significantly increased with the use of the latter sham solution. Samples A-3 and A-4 were acid treated for a period of Θ to 12 days. Samples B-3 and B-4 were treated for 3-4 days. In both methods, no change in the dimensions of the samples was obtained during the acid treatment, and no cracking or fragmentation of the diamond was observed. Any weight loss can therefore be recorded in the account of the removal of the absorbed part of the metal phase, as these acids do not dissolve the diamond.

The amount of metal phase absorbed in these extrudates was calculated to be about 8.1% by volume or 19.0% by weight, based on the density measurements of the extrudate used as a starting material for the extrusion. After soaking, 0.5% by volume or 0.2% by weight of the absorbed material remained. The removal of absorbed material up to 90% by weight (sample 4) also indicates that a relatively large amount of metal phase is located in a continuous or continuous network of pores. A scanning electron microscopic examination of the fractured surface of the soaked sample (PEM study) showed that the pore network extends throughout It turned out that the holes are distributed throughout the layer and in most en the diameter is less than 1 Jim.This indicates that the acid has penetrated the entire diamond layer and removed the metal phase mainly uniformly throughout the diamond layer.

The fracture limit and Yuong modulus of elasticity (E) were also measured for the diamond layer, as shown in Table I. Strength tests; was performed with a three-point beam loading device. Apparatus; put two steel rollers placed on the base with the third steel roll centered above it so that it! the axis is parallel to the other two rollers. The test rods were centered on the lower rollers and loaded to a fraction.

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The elongation of the test pieces was measured in parallel with the elongation stress using resistance elongation sensors connected to the resistance elongation indicator. Test pieces A-1 to A-4 were prepared for strength test and surface finishing with a diamond grinding wheel (177-250yAm) (diamond particles). Specimens B-1 to B-4 were prepared for the strength test by surface finishing on a patching machine using a 15 μm diamond grinding tool to obtain a more surface-defect-free surface than that obtained with specimens A-1 to A-4 by grinding. It is assumed that the better polished surfaces in those specimens, continue surface-treated with fine diamond, give higher strength values based on the most perfect surface conditions achieved, i.e., a smaller number of stress-concentrating defects. This is assumed to account for the low fracture limit values measured for soaked specimens (A-3, A-4, B-3, B-4). 1 / i 65935 11 f

Table I

Absorbent material- Cross-elastic- Element of elastic modulus toraja2 li (E ^ 2

Test piece (weight loss%) _ (kp / mrn) (x 10-3 kp / mm) A1 0 111 A2 0 101 A3 16.1 73 A4 16.2 87 B1 0 129 89 B2 0 143 92 B3 17.0 88 78 B4 17.9 81 80

In contrast to the fracture measurement results, porosity did not affect the E measurements (Table I) because E is a measure of the internal strength and stiffness in the material and does not contain microcracking. The mean change in E-value became only about 12% lower when the absorbed portion of the metal phase was removed from the specimens. This difference should be corrected for porosity in soaked specimens because

M-C

E = - E = Yuong modulus P1 = moment C = distance to the outer fiber I = surface moment of inertia and H · C does not change, but I decreases because the effective area is reduced with respect to porosity. If, therefore, spherical cavities and a random distribution are assumed, m is obtained. r,, £ _ _, where x = proportion of pores (pore fractions, I M-x), where the value of E becomes greater than the measured value. The average of 79 x 1Cp kp / mm2 E for samples B-3 and B-4 (soaked) is corrected to 85 x 10 kp / mm or about 5% lower than i Ί 2 j the average of 90 x 10 kp / mm E for samples B-1 and B-2.

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The removal of the absorbed part of the metal phase therefore has a very small effect on Eshe and this shows that the strength of the diamond layer depends mainly on the diamond-to-diamond bond. E-value 90 x 10 kp / mm, which can be calculated from the standard values of elasticity of a single crystal of a diamond.

Example 2

A compression piece was prepared in a manner identical to that mentioned in Example 1 for specimens A-1 to A-4, except that a mixture of diamond particles having a size of 149-177 and a size of 105-125 ^ λ, γπ was used in a ratio of 1: 1 instead of particles of Θ yuan.

The extrudates were calculated to contain 5% by weight of diamond (96.5% by volume) and 11.9% by weight of metal phase (4.5% by volume) before soaking. After soaking, a reduction of 11.5% of the total weight of the extrudate was obtained, which means that about 0.15% by weight of the metal phase (0.06% by volume) remained in the extrudate.

Example 3

Four diamond extrudates were prepared as mentioned in Example 1. The carbide was ground off from each extrudate. Of the two extrudates, the portion absorbed into the metal phase was removed by acid leaching in a hot acid mixture of 1 HF: 1 HNO 3 and 3 HCl: 1 HNO 2. All specimens were then mounted together with epoxy around a tungsten carbide substrate measuring 0.89 cm. This combined piece was mounted on a tool holder on a lathe and then a turning test was performed to examine the wear resistance. The work piece consisted of a rubber rod filled with quartz sand, trademarked by Ebonite Black Diamond. The experimental conditions were as follows: surface speed 107-168 surface meters / minute (the heat treatment group had a maximum interval of 24 13 65935 surface meters / minute), a cutting depth of 0.76 mm, a transverse feed of 0.13 mm / rev and a test time of 60 minutes. After the experiment, the test pieces were heat-treated in a dry argon environment flowing in a tube furnace. The heat treatment temperature was 700 ° C to 1300 ° C in 100 ° C increments. The exposure time was 10 minutes at each temperature. After each treatment, the specimens were examined for signs of deterioration under a scanning electron microscope and then subjected to a wear test with the exception of heat treatments at 1000 ° C, 1100 ° C and 1300 ° C. Both top and bottom blades were used as cutting blades before re-grinding.

The results of the wear test are summarized in Table II. The specimens had relatively uniform properties throughout the experiment. There was a tendency for the wear resistance to decrease from the treated space to the first heat treatment at 700 ° C. The undissolved specimens, Samples 3 and 4, did not change until the catastrophic thermal change that occurred between 800 ° C and 900 ° C. The heat treatment proved to be independent of wear resistance until the diamond phase could no longer contain an encapsulated metal phase and cracking occurred. This presence is also indicative of the presence of two different phases: the bound diamond phase, which exerts a shear effect during the machine, and the metal phase, which is a residue from the sintering process. The soaked specimens, specimens 1 and 2, withstood the heat treatment very well, up to 1200 ° C. The trend at 1200 ° C appears to be a tendency for a slight deterioration of the specimen, which may be an indication of an onset of thermal regeneration on the surface.

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Table II

Soaked Non-soaked Heat treatment Test box Test box Test box (C) _ pale 1 pale 2 pale 3 pale 4 Untreated 150-200 120-150 150 100-120 700 150 120 120 100 800 120 100 120 100 900 120 100 Radial cracks 1000 - 1100 - 1200 06-100 100-120 1300

The test results in Table II show the time per unit of wear of the extrudate at 25.4 mm x 100. Tool wear was determined by measuring the width of its flat surface with a press piece caused by contact with the workpiece. The values are meaningful only for the comparison of the relative performance of soaked and non-soaked specimens.

Soaked specimens have, on average, higher test values than non-soaked specimens. This may be due to thermal destruction or deterioration of non-soaked specimens during cutting experiments by machining the specimens. Thus, the same destruction mechanism may occur during the wear machine as during heat treatment. If this is the case, when the tool tip is heated to a high temperature in contact with the workpiece, the cobalt phase will expand more than the diamond phase and break the tip of the blade within the first few layers of particles. The damaged tip then weakens and results in poorer performance. However, soaked specimens are thermally stable at higher temperatures and do not deteriorate thermally upon contact with the workpiece.

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Scanning electron microscopy showed that the non-soaked specimens had many different properties compared to the soaked specimens. The metal phase began to erupt or penetrate out of the surface between 70 ° C and 800 ° C when examined at 2000x magnification.

When the temperature was raised to 900 ° C, the specimens cracked from the radially rounded cutting blades to the center of the specimen 'J. The soaked specimens did not have this property (but were relatively unchanged at 1300 ° C.

The diamond layers are clean at 1200 ° C, but at 1300 ° C photographs at 20x magnification show round and uneven images and photographs at 1000x magnification show an etched surface with several exposed crystals. This is presumably due to thermal deterioration or destruction of the surface, but may also be the result of minor acid B impurities in the argon environment in the tube furnace.

* Example 4

Two diamond extrudates (specimens IV-1 and IV-2) were prepared as described in Example 1, with the exception that the carbide substrate was not ground. An epoxy resin (Epon 826 with nodular methyl hydride and benzyldimethylamine curing agent) was cast around specimen IV-1 and hardened. The surface of the diamond layer was exposed by sand-grinding the entire amount of plastic on the surface of the layer. Test piece IV-1 was then placed in boiling 3 HCl: 1 HNO 2 37.15 solution for one hour. After removal from the acid, the plastic was removed from the carbide layer and examined visually. Signs of a slight reaction between the acid and the unexposed surface were observed. However, the surface of the carbide layer did not appear to be substantially acid damaged. The surface of the diamond layer was then examined by scanning electron microscopy (2000x magnification). The surface of the diamond layer had an appearance resembling the surfaces of the diamond layer of the soaked specimens of Example 1. Specimen IV-1 was then examined by energy-distributing X-ray analysis to compare the intensities of the metaphase components 16,65935 to the corresponding values of the same type of non-soaked extrudate. The result of scanning electron microscopic examination and X-ray analysis show that the acid penetrated the diamond layer and removed a substantial part of the metal phase.

In Experiments IV-1 and IV-2, a turning test was then performed to test the wear resistance as shown in Example 3 above. The result of the wear test (calculated as shown in Example 3) was 120-150 for specimen IV-1 (soaked) and 100-120 for specimen IV-2 (soaked). These test results, which show the superiority of the soaked extrudate, are consistent with the results obtained according to Example 3, and thus confirmed that removing the metal phase from the cutting blade area improves the performance characteristics of the diamond circuit die.

Claims (8)

17 65935 A tool component such as a cutting, drilling and molding tool comprising abrasive particles of diamond and / or cubic boron nitride, a metallic binder and hollow pores, characterized in that it comprises (a) said abrasive particles which are self-bonding particles and which form about 70-95% by volume of the component, (b) 0.05-3% by volume of a metal phase consisting of a sintering aid used to assist in the binding of the self-bonded particles, and (c) said pores interconnecting to form a network divided throughout the component and bounded by particles , wherein the pores comprise 5-30% by volume of the component. Tool component according to claim 1, characterized in that the particles consist of diamond and that the metal phase consists of (1) a catalytically active metal in elemental form selected from the group consisting of metals belonging to group VIII, Cr, Mn, Ta, (2) of the Periodic Table, consisting of alloying metals of a catalytically active metal or metals and non-catalytic metal or non-catalytic metals, (3) at least two alloys of these catalytically active metals, and (4) one or more catalytically active metals and one or more of a non-catalytically active metal alloy. Component according to Claim 1 or 2, characterized in that the size of the diamond particles varies between 1 and 1000 μm. A tool component according to claim 1, characterized in that the particles consist of cubic boron nitride and that the metal phase is absorbed substantially uniformly throughout the component and consists of cobalt, a cobalt alloy or an alloy of aluminum and an alloy-metal selected from the group consisting of Ni, / ^ V and Cr, Component according to Claim 1 or 4, characterized in that the particle size of the cubic boron nitride is between 1 ** and 300 μm, Component according to one of Claims 1 to 5, characterized in that the component has a cross-breakage limit of at least 35 kp / mm 2, Component according to one of Claims 1 to 6, characterized in that the component has a Young's value of 2 of at least 50,000 kp / mm, A method of manufacturing a tool component, comprising (a) introducing into the reaction chamber a mass of abrasive particles consisting of diamond or cubic boron nitride and a mass of sintering aid for abrasive particles, (b) simultaneously bringing the chamber above 40 ° C and within 1200 ° C; (c) cutting off the supply of heat to the chamber, (d) removing from the chamber an abrasive article made in steps (a) to (c), wherein the article comprises particles in a self-bonding form with the sintering aid absorbed among all the particles, characterized in that the sintering aid is removed essentially the total amount absorbed into the body so that the amount of sintering aid absorbed is about 0.05r about 3% by volume of the component, 19 PATENTKRAV 6 5 935