JP2010099779A - Super-abrasive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain the metal-bonded super-abrasive used for processing of a hard material such as cutting and drilling at a wet or dry processing, to obtain two or more kinds of super-abrasives with different brittleness without differentiating an amount of diamond or CBN and kinds of base bonds, and to obtain a super abrasive having a backing layer and using the soft base bond. <P>SOLUTION: A problem of the super-abrasive is solved by using the metal-bonded super-abrasive including hexagonal boron nitride as a solid lubricant, wherein the content of the hexagonal boron nitride is 9 wt.% or less with respect to the base bond. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a metal bond superabrasive grain, and more particularly, to a metal bond superabrasive grain used for processing of a hard material such as stone or concrete (reinforced concrete) asphalt by wet or dry cutting or drilling. Moreover, it is related with the metal bond superabrasive grain widely used especially for the processing of concrete by a dry type especially.

  The superabrasive grains are produced by sintering diamond, CBN (cubic boron nitride) or the like together with a base bond. The superabrasive grains are joined to the substrate by brazing, welding or the like as segment chips and used for cutting, cutting, drilling, and polishing.

  Super abrasive grains can be classified according to the type of base bond. Resin bond super abrasive grains using resins such as resinoids, vitrified bond super abrasive grains using ceramics, metal bond super abrasive grains using metal powder, etc. There is.

  Depending on the hardness and size of the object to be cut, the wear resistance and brittleness required for superabrasive grains vary. In addition, when a plurality of rotary blades are attached to a cutting device and a plurality of cuttings are performed at the same time, depending on the change in pressure due to the number of super abrasive grains arranged, the output of the cutting device, the rotational speed, etc., the super abrasive particles There are various wear resistance and brittleness required.

  In order to obtain such superabrasive grains having various wear resistance and brittleness, conventionally, a difference was obtained depending on the blending ratio of metal powder used for the base and the sintering method (sintering temperature and time). . That is, for example, a hard bond is suitable for a soft cutting material, so that the compounding ratio of tungsten is increased, and a soft bond is suitable for a hard cutting material, so that the compounding ratio of bronze or silver is increased.

  In Patent Document 1, in order to obtain high grinding ability by vitrified bond, one or two or more lubricants selected from molybdenum disulfide, hexagonal boron nitride, and graphite are used as a solid lubricant in the volume ratio in the abrasive grains. What is characterized by containing 0.05%-5% is disclosed.

  Patent Document 2 discloses a cutting insert that has a three-layer structure of a base layer, an intermediate layer, and a surface layer, and uses hexagonal boron nitride for the surface layer and the intermediate layer.

  Patent Document 3 discloses a material containing both polyimide resin and metal and using hexagonal boron nitride as a lubricant.

Patent Document 4 discloses a resin bond using graphite grains and hexagonal boron nitride grains as an improving agent. In Patent Document 4, hexagonal boron nitride as an improving agent is used whose particle size is as large as 1.2 to 3.8 times the average particle size of superabrasive grains. As the grinding process is performed, hexagonal boron nitride is removed from the bond resin, and the removed part becomes a void larger than the superabrasive grains, and this void (pocket) functions to temporarily store the grinding fluid and grinding powder. As a result, it is possible to grind at a high grinding ratio with good sharpness.
JP 2000-61847 A JP 2004-338041 A JP 2004-50331 A JP 2007-15054 A

  With superabrasive grains, scraps generated during cutting scrape the base bond to cause wear of the base bond, which promotes the self-growth of diamond (or CBN), and cutting is performed by the self-generated diamond (or CBN). .

  The superabrasive grains used for hard work materials such as dry cutting of concrete are suitable for metal bond super abrasive grains. However, since the work materials are hard, the amount of cutting per hour is relatively small. The amount of chips is small and fine, and the base metal bond is not sufficiently worn. For this reason, the diamond is not sufficiently grown and cutting failure occurs.

  Therefore, a soft and highly brittle metal bond superabrasive grain is required as a superabrasive grain used for a hard work material such as dry cutting of concrete.

  Softness can be obtained by adding bronze or silver as a metal composition for the base, but the brittleness is low and the self-acceleration of diamond by cutting waste is insufficient. In addition, due to the softness, when an impact or stress is applied to diamond or other superabrasive grains, the bond will slip into the bond or fall off, and sufficient cutting cannot be obtained. Therefore, the mixing ratio is adjusted according to the hardness of the work material to obtain an optimum material.

  Referring to FIG. 1, superabrasive grains (1) are scraped off from corner portions during cutting (b). Therefore, when the brittleness of the superabrasive grains is uniform, the corners of the superabrasive grains are rounded off (c), and the contact area with the work material increases, so that the pressure required for cutting increases. This increases the cutting load and makes it difficult to go straight. In addition, it is difficult to go straight because it is susceptible to left and right stress. As a result, both side surfaces were scraped, the superabrasive grains (1) became the same width as the substrate (10) (d), and became unusable in a short period of time.

  Conventionally, superabrasive grains have a longitudinal layer structure, and the outer layer (2) is more brittle than the inner layer (3) (FIG. 2). Such layer structures with different vulnerabilities have been conventionally obtained by using the same base bond for each layer and varying the content of diamond (or CBN). That is, regarding the content of diamond or the like, the outer side was increased and the inner side was decreased so that the outer side was more wearable than the inner side. It was not possible to use different base bonds because the sintering conditions were different depending on the base bond. Superabrasive grains are scraped from the corners during cutting (reference numeral b in FIG. 2), but by making a layer structure in the vertical direction, cutting proceeds without scraping both sides (see FIG. 2). Symbol c), the width of the superabrasive grains could be maintained for a long time. In addition, although a three-layer structure is shown in the figure, there are also superabrasive grains having a five-layer or seven-layer structure in order to further improve the wear form.

  Referring to FIG. 3, when superabrasive grains are welded to a substrate, in order to perform welding with sufficient strength, a backing layer ( A layer called 4) having good weldability with the substrate has been provided. The backing layer is usually a layer in which diamond and CBN are not mixed, and a layer other than the backing layer in the superabrasive grains (1) is called a mix layer (5). The composition of the backing layer must be selected based on the weldability with the substrate in order to enable welding with the substrate. In order to satisfy the condition, it is necessary to make a hard layer because a soft composition cannot be adopted. Furthermore, in order to ensure sufficient adhesion between the backing layer and the mix layer, both base bonds must be identical or very close in composition.

  When the object to be cut is hard, such as dry cutting of concrete, it is necessary to use a soft base bond, but it is necessary to provide a backing layer for the necessity of welding to the substrate, and to make the base bond the same or close in composition to the backing layer There is. For this reason, the base bond of the mix layer must be hard. Therefore, the superabrasive grains used for dry cutting of concrete have the above-mentioned three-layer structure, so that the best use can be achieved even if a hard base bond is used.

  However, this means is extremely insufficient, and there has been a demand for the development of superabrasive grains capable of excellent cutting, drilling and polishing when the object to be cut is hard, such as dry cutting of concrete.

  Metal bond superabrasive grains, which have good chip discharge and good sliding with the work material during cutting, drilling and polishing, smooth chip discharge, and low-temperature chip adhesion. An object is to obtain excellent superabrasive grains.

  It is an object of the present invention to obtain metal bond superabrasive grains used for processing such as wet, dry cutting and drilling of hard materials such as stone, concrete (reinforced concrete) and asphalt. In particular, an object of the present invention is to obtain metal bond superabrasive grains that are widely used in dry concrete processing.

  It is a metal bond, and hexagonal boron nitride is mixed as a solid lubricant, and it is a problem to obtain super abrasive grains with high and low brittleness due to the difference in hexagonal boron nitride content. And

  It is an object to obtain superabrasive grains having two or more types of fragility without making the amount of diamond or CBN and the type of base bond different.

  It is an object of the present invention to obtain superabrasive grains which have a backing layer and can use a soft base bond.

  It is an object of the present invention to obtain superabrasive grains having different wearability and brittleness under the same sintering conditions.

  In claim 1, the problem is solved by metal bond superabrasive grains containing hexagonal boron nitride as a solid lubricant.

  Hexagonal boron nitride has a layered structure and functions as a solid lubricant without deterioration in oxidation resistance up to 900 ° C. As a result, the sliding between the superabrasive grains and the work material is good, and chip adhesion due to high temperature is suppressed. The superabrasive grains are brittle and do not lose their function as a solid lubricant, so that excellent cutting, drilling and polishing conditions can be maintained for a long time.

  In claim 2, the problem is solved by metal bond superabrasive grains in which the content of hexagonal boron nitride is 9% by weight or less with respect to the base bond.

  Hexagonal boron nitride does not react with the molten metal, exists without chemically fusing with other materials in the superabrasive grains, and functions as a barrier to the fusion of other materials in the superabrasive grains. The strength of the sintered body can be obtained by bonding between metals. However, the presence of hexagonal boron nitride inhibits bonding between metals, and as a result, brittleness and wear of metal bonded superabrasive grains can be obtained. If the content of hexagonal boron nitride is more than 9% by weight, the brittleness becomes too high, and the effect of adding hexagonal boron nitride cannot be sufficiently obtained.

  In claim 3, the particle size of hexagonal boron nitride is 50 μm or less, and the problem is solved by the metal bond superabrasive grains according to claim 1 or 2.

  Setting the particle size of hexagonal boron nitride to 50 μm or less means that the particle size of hexagonal boron nitride is the same as or smaller than that of metal powder used for the base bond. As a result, the hexagonal boron nitride grains prevent sufficient bonding of the metal powder used for the base bond, resulting in brittle superabrasive grains. The wear resistance of the base bond is increased, and as a result, the diamond (or CBN) is sufficiently grown. Because of such a configuration, for example, even if the particle diameter exceeds 50 μm and is 60 μm, the same effect can be obtained by increasing the content of hexagonal boron nitride. In addition, since the metal powder particles used for the base bond generally have a width of about several microns to 50 μm, the hexagonal boron nitride particle size is uniformly dispersed and the bonds between the metals are uniform. It is preferable that the particle size of the metal powder used for the base bond is equal to or smaller than that (1 to 10 μm).

  In the present invention, the mechanism by which hexagonal boron nitride enhances the wear properties of superabrasive grains is important in terms of differences from Japanese Patent Application Laid-Open No. 2007-15054 (Patent Document 4). That is, in the invention described in Japanese Patent Application Laid-Open No. 2007-15054, a hexagonal boron nitride having a very large particle size of 1.2 times to 3.8 times the average particle size of superabrasive grains is used. The structure is different from the present invention in that it is provided with high wear by utilizing the fact that the cutting scraps scrape off the bond by the turbulent flow in the large holes formed when the crystalline boron nitride falls off.

  According to claim 4, the hexagonal boron nitride is not combined with the base bond, and the problem is solved by the metal bond superabrasive according to claim 1 or 2.

  Such a metal bond superabrasive grain can be obtained by using a metal that does not chemically react with hexagonal boron nitride as a metal used as a base bond. The mixing ratio of the metal bond is, for example, 40% of iron, 40% of cobalt, 12% of copper, 5% of silver, and 3% of superabrasive grains.

  In Claim 5, it has a several layer from which abrasion differs, The problem is solved by the metal bond superabrasive grain of Claim 1 or Claim 2 characterized by the above-mentioned.

  According to a sixth aspect of the present invention, there is provided a plurality of layers having different hexagonal boron nitride contents, and the problem is solved by the metal bond superabrasive grains according to the first or second aspect.

  By making the content of hexagonal boron nitride different, the wearability can be made different. Thereby, in the case where the kind of base bond and the amount of diamond (or CBN) are the same, the wear property can be enhanced by adding hexagonal boron nitride. And until it exceeds a predetermined amount, the wear resistance increases as the content of hexagonal boron nitride increases. Therefore, by making the content of hexagonal boron nitride different, it is possible to obtain a single super-whetstone having portions with different wear properties.

  When a single super-whetstone having parts with different wear properties is obtained, since a single base bond is used, it is very easy to set sintering conditions.

  In one superabrasive stone, it is possible to freely determine in what position and in what shape the wear-resistant part is provided depending on the object to be cut. What is used as the base bond can be freely determined depending on the object to be cut.

  A method for producing a super whetstone having a plurality of layers having different hexagonal boron nitride contents is the same as the conventional method. In other words, there is a method in which a plurality of cold pressing molded bodies having different hexagonal boron nitride contents are formed and then the plurality of cold pressing molded bodies are integrally sintered. As another method, metal powder, diamond (or CBN), and hexagonal boron nitride are mixed at a predetermined ratio, and a plurality of such mixtures having different mixing ratios of hexagonal boron nitride are prepared and sintered. There is a method in which a layered structure is put into a binding die in a predetermined order to form a layer structure and sintered.

  7. The metal according to claim 5, wherein the metal layer has a layer structure arranged in a longitudinal direction, and the outer layer has a layer structure having lower wear than the inner layer. The problem is solved by bond superabrasive grains.

  The layer structure is arranged in the vertical direction, and the wear of the outer layer is lower than the wear of the center part, so that the wear of the side surface (outer layer) can be suppressed during cutting work. The cutting ability can be maintained for a long time. Since the superabrasive stone according to the present application is composed of a single base bond, by using a sintering condition suitable for the base bond to be composed, a layer structure having excellent wear resistance and sufficient bonding of each layer can be obtained. A ligation can be obtained. Conventionally, in order to use the same metal bond and make the wear of each layer different, there was only a method of making the diamond content different. In the super grinding stone according to the present application, the amount of diamond in each layer is the same. In addition, it is possible to obtain a super grindstone having a multilayer structure in which the outer layer is more wearable than the inner layer.

  As a result, it is possible to change the wear characteristics more greatly than before, making it more suitable for various work materials and machines used than before, and enabling the optimum wear form as shown in FIG. Possible to produce super abrasive grains. Moreover, the use fee of diamond can be suppressed and an inexpensive product can be obtained.

  In claim 8, the plurality of layers are formed of the same base bond, and the problem is solved by the metal bond superabrasive grain according to any one of claims 5 to 7.

  Conventionally, the difference in wear has been obtained by the difference in the components of the base bond. Because there is an optimum sintering temperature and optimum sintering time for each component of the base bond, it is extremely difficult to produce a super whetstone with multiple layers, maintaining good wear resistance and excellent machinability for a long period of time. I couldn't get a segment with the ability.

  Since the super whetstone according to the present application is composed of a single base bond, a very good sintered body can be obtained by using only the sintering conditions suitable for the base bond to be constructed.

  In Claim 9, a backing layer does not contain a diamond or CBN, The problem is solved by the metal bond superabrasive grain in any one of Claim 5 thru | or 8.

  In Claim 10, the backing layer does not contain hexagonal boron nitride, and the problem is solved by the metal bond superabrasive grains according to any one of Claims 5 to 9.

  In claim 11, the problem is solved by metal bond superabrasive grains containing graphite as a solid lubricant. Like hexagonal boron nitride, graphite can be mixed as an impurity in the base metal bond, and is easily broken and does not interfere with the wear of the superabrasive grains. If a base that does not chemically react with graphite is used, the required brittleness is obtained and combustion due to frictional heat does not occur.

  In Claim 12, the content of graphite is 9 wt% or less with respect to the base bond, and the particle size of graphite is 50 µm or less. Resolve.

  Metal bond superabrasive grains, which have good chip discharge and good sliding with the work material during cutting, drilling and polishing, smooth chip discharge, and low-temperature chip adhesion. Excellent superabrasive grains can be obtained.

  Metal-bond superabrasive grains that can be used favorably in wet and dry cutting of hard materials such as stone and concrete (reinforced concrete) asphalt can be obtained. Further, it is possible to obtain metal bond superabrasive grains that are favorably used for processing such as dry concrete cutting.

  It is a metal bond, and hexagonal boron nitride functions as a solid lubricant. Due to the difference in the content of hexagonal boron nitride, it is possible to obtain a superabrasive, highly brittle and weak.

  By making it possible to sinter metal bonds having different wear properties under the same sintering conditions, it is possible to obtain segment chips having different wear properties in a single sintered body.

  Under the same sintering conditions, superabrasive grains having portions with different wear and brittleness can be obtained.

  Embodiments of the present invention will be described below in Embodiments 1 to 4.

Work: Dig 15 grooves with a depth of 6 mm at 40 mm intervals in concrete without using water.
Machine: Boarding type dry grooving machine (engine output 36.8kw, shaft rotation speed 2,300min- ¹ )
Blade: 15 mm outer diameter, 15 on the same rotating shaft at 40 mm intervals Segment chip: 6 mm thickness
Cutting depth: 6mm

result:

Work: Dig a joint with a depth of 6 mm in concrete without using water.
Machine: Dry concrete cutter (engine type output 12.5kw, shaft rotation speed 2,300 min ^-1 )
Blade: Outer diameter 300mm, Single segment tip: Thickness 5mm
Cutting depth: 6mm

result:

Work: Drill holes with a diameter of 25 mm and a depth of 250 mm in concrete without using water.
Machine: Electric drilling machine (motor output 1.5kw, shaft rotation speed 4,300 min ^-1 )
Drilling diameter: 25mm
Drilling depth: 250mm

result:

Experiment: Using a sandblast (a product of Fujikoshi Co., Ltd.), a comparative experiment of the amount of hexagonal boron nitride added was conducted with respect to the amount of wear of superabrasive grains. In Tables 1 to 4, base bonds to which hexagonal boron nitride was added used the same material and were sintered under the same conditions. The amount of hexagonal boron nitride added is expressed as a percentage by weight relative to the base bond.
Air pressure: 5 kg / cm ²
Sandy whetstone: carbon random (particle size about 150μm)
Injection distance: 40mm
Injection time: 90 seconds

result:

  From the above experimental results, it was found that by changing the addition amount of hexagonal boron nitride, superabrasive grains having different wear amounts can be obtained under the same sintering conditions. In addition, it was found that by adding hexagonal boron nitride to the base bond, superabrasive grains having wearability exceeding the wearability of 100% bronze metal bond, which was said to be the most wearable, were obtained. .

The progress of wear of superabrasive grains is shown. The progress of wear of superabrasive grains is shown. Superabrasive grains are shown. Superabrasive grains are shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Superabrasive grain 2 Outer layer 3 Center layer 4 Backing layer 5 Mix layer 10 Substrate

Claims (12)

Metal bonded superabrasive grains containing hexagonal boron nitride as a solid lubricant. Metal bond superabrasive grains in which the content of hexagonal boron nitride is 9% by weight or less based on the base bond. The metal bond superabrasive grain according to claim 1 or 2, wherein the hexagonal boron nitride has a grain size of 50 µm or less. The metal bond superabrasive grain according to claim 1 or 2, wherein hexagonal boron nitride is not combined with a base bond. The metal-bonded superabrasive grain according to claim 1, comprising a plurality of layers having different wear properties. The metal bond superabrasive grain according to claim 1 or 2, comprising a plurality of layers having different hexagonal boron nitride contents. 7. The metal bonded superabrasive grain according to claim 5, wherein the metal bonded superabrasive grain has a layered structure arranged in a longitudinal direction, wherein the outer layer has a layered structure having lower wear than the inner layer. The metal bond superabrasive grain according to any one of claims 5 to 7, wherein a plurality of layers are made of the same base bond. The metal bonded superabrasive grain according to any one of claims 5 to 8, wherein the backing layer does not contain diamond or CBN. The metal bond superabrasive grain according to any one of claims 5 to 9, wherein the backing layer does not contain hexagonal boron nitride. Metal bonded superabrasive grains containing graphite as a solid lubricant. The metal bond superabrasive grain according to claim 11, wherein the content of graphite is 9% by weight or less based on the base bond, and the particle size of graphite is 50 µm or less.

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