KR20160066280A - Method of fabricating powder for diamond tool, and cutting segment using the same - Google Patents

Abstract

Provided is a method of fabricating powder for a diamond tool. The method comprises: a step of preparing iron powder having carbon and metal compound powder; and a step of fabricating alloy powder by mixing the iron powder with the metal compound powder and mechanically alloying the mixed powder, wherein the alloy powder includes stacked plate structures made of iron contained in the iron powder; and the metal compound powder inserted between the plate structures. The plate structure have crystal defects therein. As such, the present invention improves quality variation and cutting properties.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing diamond powder,

The present invention relates to a method of manufacturing a powder for a diamond tool and a method of manufacturing a cutting tip using the same, and more particularly, to a method of mechanically alloying an iron powder and a metal compound powder to improve internal microstructure, The present invention relates to a method of manufacturing a powder for a diamond tool capable of manufacturing a tool, and a method of manufacturing a cutting tip using the same.

In diamond cutting tools, cobalt powder is generally used as a raw material for a sintered body (binder) of a cutting tip. These cobalt powders can be widely applied as raw material powders of diamond cutting tools, irrespective of kinds of granite, concrete, asphalt, marble, etc., and regardless of the high horsepower and low horsepower of the cutting machine used. In addition, a cutting tip produced from cobalt powder as a raw material easily protrudes diamond particles during cutting, thereby improving cutting efficiency. Due to the abovementioned advantages, cobalt powder is being referred to as "universal metal powder" in the field of diamond tools.

For example, Korean Patent Registration No. 10-0201349 (Application No. 10-1996-0006855, filed by Ewha Diamond Industrial Co., Ltd.) discloses a method in which a diamond powder is coated with a metal bond powder, And the segments are formed by firing to form segments for diamond tools, wherein the granules and the metal bond powder are molded into granules and the granules are formed to have the same size with each other.

However, cobalt powder is not only expensive, has a large price fluctuation, but also has environmental problems harmful to the human body. As a result, much research and development is underway to develop a metal powder capable of replacing cobalt powder.

Iron powder is inexpensive and has relatively less environmental pollution as compared with cobalt powder, and iron powder is being discussed as a substitute for cobalt powder.

At present, there are various kinds of commercially available iron powder, such as water-soluble iron powder, gas-jet iron powder, reduced iron powder, carbonyl iron powder, and the like. It is difficult to obtain a dense structure after sintering even if a carbon material is produced using carbonyl iron powder having a fine particle size. Therefore, high-temperature sintering at 1000 DEG C or more is required to increase the sintering density.

However, when the sintering temperature is increased, the diamond particles mixed in the binder are transformed into graphite and the strength is rapidly lowered, thereby accelerating the deterioration of the diamond. As the diamond particles deteriorate, there arises a problem that the machinability and the usable period of time are reduced as a cutting tip. Accordingly, it is necessary to develop a process capable of sintering at a temperature of 900 DEG C or lower.

In addition, the binding material sintered with a commercially available iron powder has a lower hardness and an unfavorable force than cobalt, has poor mechanical supportability to diamond particles, and is not smoothly worn, resulting in poor cutting performance.

Patent Registration Bulletin 10-0201349

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a method for manufacturing a highly reliable diamond tool powder and a method for manufacturing a cutting tip using the same.

It is another object of the present invention to provide a method for manufacturing a diamond tool powder with minimized quality deviation, and a method for manufacturing a cutting tip using the same.

It is another object of the present invention to provide a method of manufacturing a diamond tool powder with improved cutting characteristics and a method of manufacturing a cutting tip using the same.

The technical problem to be solved by the present invention is not limited to the above.

In order to solve the above technical problems, the present invention provides a method of manufacturing a diamond tool powder.

According to one embodiment, there is provided a method for producing a metal alloy powder, comprising: preparing an iron powder and a metal compound powder containing carbon; and mechanically alloying the iron powder and the metal compound powder to prepare an alloy powder, The powder may include a layered plate-like structure formed of iron contained in the iron powder, and a powder of the metal compound interposed between the plate-shaped structures, and having crystal defects in the plate-shaped structure have.

According to one embodiment, the method further comprises preparing a low melting point metal powder having a melting point lower than iron, wherein the low melting point metal powder may be subjected to mechanical alloying with the iron powder and the metal compound powder .

According to one embodiment, the mechanical alloying treatment may be performed in air or in an inert gas atmosphere by any one of a vibrating ball mill, a streamlined ball mill, a cylindrical ball mill, or a centrifugal ball mill.

In order to solve the above technical problems, the present invention provides a method of manufacturing a cutting tip for a diamond tool.

According to one embodiment, there is provided a method of manufacturing a diamond tool, comprising the steps of: preparing a powder for a diamond tool according to the above-described embodiments; and mixing and sintering the diamond tool powder and the powder of diamond particles to produce a cutting tip composed of a binder and diamond particles Wherein the metal compound powder does not have pores in the binder within the cutting tip.

According to one embodiment, there is provided a method of manufacturing a diamond tool, comprising the steps of: preparing a powder for a diamond tool according to the above-described embodiments; and mixing and sintering the diamond tool powder and the powder of diamond particles to produce a cutting tip composed of a binder and diamond particles Melting metal contained in the metal compound powder and the binder in the vicinity of grain boundaries of the metal compound powder and the binder may be higher than the content of the low melting point metal in the binder matrix.

According to one embodiment, the diamond tool powder and the diamond powder may be sintered at a temperature of 750 to 900 占 폚, in air or under an inert gas atmosphere, or in a reduced-pressure atmosphere.

According to the embodiment of the present invention, after the iron powder and the metal compound powder are mixed, they are mechanically alloyed to produce an alloy powder. The alloy powder includes a layered plate-like structure formed of iron and the metal compound powder interposed between the plate-shaped structures, and has a crystal defect in the plate-shaped structure. Accordingly, it is possible to provide a highly reliable diamond tool powder having a reduced sintering temperature in the sintering process using the alloy powder, improved wear characteristics of the sintered body, minimized quality deviation, and improved cutting characteristics, and a cutting tip using the same .

1 is a flowchart illustrating a method of manufacturing a diamond tool powder according to an embodiment of the present invention.
2 is a schematic diagram showing a powder for a diamond tool according to an embodiment of the present invention.
3 is a flowchart illustrating a method of manufacturing a cutting tip using powder for a diamond tool according to an embodiment of the present invention.
FIG. 4 is a view showing that a cutting tip manufactured according to a method of manufacturing a cutting tip according to an embodiment of the present invention is bonded to a steel core. FIG.
Fig. 5 is an enlarged view of Fig. 4A.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the technical spirit of the present invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the embodiments disclosed herein are provided so that the disclosure can be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

In this specification, when an element is referred to as being on another element, it may be directly formed on another element, or a third element may be interposed therebetween. Further, in the drawings, the thicknesses of the films and regions are exaggerated for an effective explanation of the technical content.

Each embodiment described and exemplified herein also includes its complementary embodiment. Also, in this specification, 'and / or' are used to include at least one of the front and rear components.

The singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. It is also to be understood that the terms such as " comprises "or" having "are intended to specify the presence of stated features, integers, Should not be understood to exclude the presence or addition of one or more other elements, elements, or combinations thereof.

In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

FIG. 1 is a flow chart for explaining a method of manufacturing a diamond tool powder according to an embodiment of the present invention, and FIG. 2 is a schematic diagram showing a diamond tool powder according to an embodiment of the present invention.

Referring to FIGS. 1 and 2, an iron powder and a metal compound powder containing carbon are prepared (S110). A trace amount of carbon may be contained in the iron powder. For example, 0.02 wt% or less of carbon may be contained in the iron powder. The metal compound powder may include at least one of a metal oxide, a metal nitride, and a metal carbonitride

The iron powder and the metal compound powder may be mixed and mechanically alloyed to produce an alloy powder (S120). According to one embodiment, the step of mechanically alloying the iron powder and the metal compound powder may be performed by any one of a vibrating ball mill, a streamlined ball mill, a cylindrical ball mill, or a centrifugal ball mill in air or in an inert gas atmosphere .

The alloy powder produced by the mechanical alloying treatment may include a laminated plate-like structure 110 formed of iron contained in the iron powder, and the metal compound powder 120 interposed between the plate-shaped structures 110 . The alloy powder may have an apparent density of about 2.5 to 3.5 g / cm ³ , an average particle size of about 5 to 30 μm, and a powder having a size of 10 μm or less of about 45 wt% or more.

The thickness of the plate-like structure 110 may be about 0.03 to 0.5 mu m. Inside the plate-like structure 110 formed of iron, crystal defects may exist due to the impact energy accumulated in the mechanical alloying process. For example, the plate-like structure 110 may include at least one of a vacancy, a stacking fault, a dislocation, and a grain boundary.

The metal compound powders 120 may be substantially uniformly distributed between the plate-like structures 110. For example, the metal compound powder 120 may have a size of about 0.01 to 0.5 μm, and the metal compound powder 120 may have a content of about 0.5 to 5.0 vol%. The distance between the metal compound powders 120 may be about 0.01 to 0.5 mu m.

According to one embodiment, in addition to the iron powder and the metal compound powder, a low-melting point metal powder may be further prepared. For example, the low-melting-point metal powder may include at least one of tin (Sn), copper (Cu), and tin-copper alloy . The low melting point metal powder may be mechanically alloyed together with the iron powder and the metal compound powder.

Hereinafter, a method of manufacturing the cutting tip using the powder for diamond tool manufactured according to the above-described method will be described.

FIG. 3 is a flow chart for explaining a method of manufacturing a cutting tip using powder for a diamond tool according to an embodiment of the present invention. FIG. 4 is a cross-sectional view illustrating a cutting tip manufactured according to the method of manufacturing a cutting tip according to an embodiment of the present invention. Fig. 5 is an enlarged view of Fig. 4A. Fig.

Referring to FIGS. 3 to 5, a powder for a diamond tool is prepared (S210) according to the method described with reference to FIGS. 1 and 2, wherein the iron powder and the metal compound powder are alloyed with the alloy alloy.

The powder for diamond tool and the powder of diamond particles are mixed and sintered to produce a cutting tip 220 (S220). The cutting tip 220 may be attached to the substrate 210 to provide a diamond cutting tool. The substrate 210 may be formed of an iron plate.

The cutting tip 220 may include a binder 222 formed of the powder for the diamond tool and diamond particles 224 (abrasive) distributed on the binder 222. The binder 222 may be combined with the diamond particles 224 to support the diamond particles 224. [ At least a portion of the diamond particles 224 may be protruded outwardly from the binder 222. Accordingly, the workpiece can be easily cut by the cutting tip 220.

The binder may have a relative density of 96% or more, a ferrite grain size of about 10 m or less, a hardness of HRB 90 or more, and a transverse rupture strength of the binder of 1000 MPa or more.

As described above, according to the embodiment of the present invention, the alloy powder produced by mechanically alloying the iron powder and the metal compound powder has a plate-like structure 110, and a large amount of crystals There may be a fault. Crystallographic defects, including stacking faults, dislocations, grain boundaries, vacancies, etc., can be the circuit path through which atoms move in the sintering process. Accordingly, the alloy powder and the powder of the diamond particles having a large number of crystallographic defects can be sintered at a low temperature.

If the sintering temperature is 900 ° C or higher, the diamond particles 224 may be transformed into graphite in the sintering process, which may degrade the cutting characteristics of the cutting tip 220. However, as described above, the alloy powder according to the embodiment of the present invention may have a large amount of crystallographic defects in the plate-like structure 110, and thus the sintering temperature may be reduced to 900 캜 or less. This prevents the diamond particles 224 from being transformed into graphite, so that a cutting tip with improved cutting characteristics can be provided.

In addition, due to the crystallographic defects in the plate-like structure 110, recrystallization of iron occurs smoothly during the sintering process, and the binder 222 can be densified. In other words, as the crystallographic defects are increased, the nucleation sites of the recrystallization are increased to produce fine grains, and the hardness, resistance and mechanical properties of the binder 222 can be improved. Thus, the binder 222 having a dense structure at a low temperature sintering temperature can be produced.

Also, as described above, according to the embodiment of the present invention, the iron powder includes carbon, and the carbon content may be 0.02 wt% or less. In the sintering process, a diffusion reaction may occur between the powder of the diamond particles and the iron powder contained in the alloy powder. In other words, carbon atoms in the diamond are diffused into iron. At this time, the solubility limit of the carbon atoms of iron is the driving force of the diffusion reaction. The iron powder according to an embodiment of the present invention may include 0.02% by weight or less of carbon, which is the solubility limit of carbon in which ferrite can be dissolved.

If the iron powder contains a large amount of carbon, the amount of the carbon atoms of the diamond diffused into the iron can be reduced. As a result, carbon having a solubility limit of 0.02% or more of carbon which the ferrite which is a room temperature phase of iron can solidify is present as pearlite. When the content of pearlite is increased in the binder 222, the interface bonding force between the diamond particles 224 and the binder 222 may be reduced. In this case, the binding material 222 supports and retains the diamond particles 224, and the diamond particles 224 can be easily separated from the binding material 222. As a result, the cutting characteristics and life characteristics of the cutting tip 220 may be deteriorated.

However, as described above, according to the embodiment of the present invention, the content of carbon in the iron powder may be 0.02% by weight or less, so that the content of the perlite in the binder 222 is minimized, I can not. This increases the binding force between the binder 222 and the diamond particles 224 and increases the diamond retention force of the diamond particles 224, The cutting characteristics and the life characteristics of the cutting tip 220 can be improved.

The diamond particles 224 can continue to easily cut the workpiece when the diamond particles 224 are appropriately exposed and protruded due to the wear of the binder 222 properly. If the binder 222 is not adequately worn, the diamond particles 224 may be covered by the binder 222 without being exposed and protruded. In this case, the workpiece is not cut by the diamond particles 224, and this phenomenon is referred to as glazing. In addition, unlike the above, if the abrasion speed of the binding material 222 is excessively high, the diamond 224 easily separates from the binding material 222 and the life of the cutting tip 220 may be reduced have.

During the cutting of the work material, the binder 222 is worn out, and a part (small grain, debris) of the binder 222 is peeled off. If the size of the particles of the binder 222 to be peeled off is small, the wear rate of the binder 222 may be reduced, so that the diamond particles 224 relatively slowly expose and protrude, The lifetime of the battery 220 can be increased.

In addition, the bonding force of the particles of the binder 222 to be peeled off can be adjusted according to the horsepower using the cutting tip 220. For example, when the cutting tip 220 is used on a machine with a large horsepower, the force applied to the cutting tip 220 is large, and the wear rate of the binder 222 is fast. On the other hand, a small horsepower machine may have a small force applied to the cutting tip 220, so that the grain may not be peeled off and the above-described clogging phenomenon may occur. Accordingly, when the cutting tip 220 is used for a machine having a relatively large horsepower, it is advantageous for the grains to be peeled off from the binder 222 to have a high bonding force, 220 is used, it is advantageous that the bonding strength of the grains to be peeled off from the binding material 222 is low.

In order to solve the above-described problems, according to an embodiment of the present invention, the metal compound powder may include at least one of oxide, nitride, and carbonitride. The metal compound powder containing at least one of the oxides, nitrides, and carbonitrides is a heterogeneous material different from the iron structure (ferrite) that is the base structure of the binding material 222, It is a brittle material. As a result, a large number of crack origins can be distributed in the matrix of the binder 222, and the size of the granules to be stripped from the binder 222 can be reduced by the origin of the many distributed cracks. According to the embodiment of the present invention, the gap between the metal compound powders as the brittle material is narrow, that is, the metal compound powder is finely and infinitely distributed in the binder material 222, The size of the above-mentioned granules can be further reduced. As a result, the wear rate of the binder 222 is reduced, and the life of the cutting tip 220 can be improved.

If the size of the metal compound powder exceeds 0.5 μm, there is a risk that the strength of the cutting tip 220 is lowered and the cutting tip 220 is broken during the cutting process. If the size of the metal compound powder is 0.01 μm , It may not serve as a starting point of cracking that causes the binder 222 to be peeled off with small grains. Accordingly, according to the embodiment of the present invention, the particle size of the metal compound powder may be 0.01 to 0.5 탆.

According to an embodiment of the present invention, in the mechanical alloying process, the iron powder may be laminated in the form of a thin flake to have a multi-layer structure. At the interface between the plate and the plate, the metal compound powder may be present as described above. The thickness of the plate may be an interval between the metal compound powders in the binder 222 of the sintered cutting tip 220. Accordingly, if the thickness of the plate is large, the interval between the metal compound powders in the binder 222 can be increased. Alternatively, if the thickness of the plate is reduced, the interval between the metal compound powders in the binder 222 may be narrowed. In this case, as described above, when the distance between the metal compound powders is narrowed, the size of the particles to be peeled off from the binder 222 is reduced, and the wear performance of the binder 222 can be improved. Thus, according to an embodiment of the present invention, in the alloyed mechanically alloyed powder, the thickness of the plate of the plate-shaped structure 110 formed of iron may be 0.03 to 0.5 mu m.

According to one embodiment, as described above, the alloy powder further includes the low-melting-point metal powder having a lower melting point than iron in addition to the iron powder and the metallic compound powder, and the low- The alloy powder and the powder of the diamond particles are mixed and sintered so that the cutting tip 220 can be manufactured. The content of the low melting point metal present in the portion of the metal compound powder and the binder 222 adjacent to the grain boundaries may be higher than the content of the low melting point metal present in the base of the binder 222.

As described above, when the horsepower of the machine used in the cutting process is relatively small, the force applied to the cutting tip 220 is small, so that wear and tear of the binder 222 may be insufficient and clogging may occur. In order to solve such a problem, it is necessary to reduce the bonding force of the internal structure of the binder 222 in order that the binder 222 is properly worn in a machine having a relatively small horsepower. As described above, when the cutting tip 220 is manufactured using the low melting point metal, the interface between the interface between the metal compound powder inside the binder 222 and the interface between the low melting point The metal powder may be present in the form of a film. In this case, when the temperature of the cutting tip 220 rises in the cutting process, the strength of a part of the binder 222 in which the film formed of the low melting point metal powder is present is lowered, Wear. In other words, the binding force of the internal structure of the binding material 222 is reduced by the low melting point metal powder, so that the binding material 222 can be easily worn.

When the content of the low melting point metal powder is changed, the thickness of the film formed of the low melting point metal powder present in the binding material 222 is changed, thereby changing the binding force of the internal structure of the binding material 222, The binding force of the particles to be peeled from the binding material 222 can be changed. In addition, when the content of the low melting point metal powder is excessively low, the effect of improving the wear characteristics of the binder 222 may not be exhibited. Accordingly, the content of the low melting point metal powder may be 0.01 to 10% by volume.

Hereinafter, a method of manufacturing a diamond tool powder and a method of manufacturing a cutting tip using the diamond tool according to an embodiment of the present invention will be described in detail.

Iron powder (Fe ₂ O ₃ , product of Sigma-Aldrich, powder size: 1.5 μm or less) was prepared as a powder of iron powder (Hoganas product name: ASC 300, powder size: 45 μm or less) and metal compound powder. According to Examples and Comparative Examples of the present invention, the volume fraction of iron oxide powder was varied, and an alloy powder was produced by a mechanical alloying method.

Example 1

The iron powder was added so that the volume fraction of the iron oxide powder was 1%, and then subjected to a mechanical alloying treatment to produce an alloy powder according to Example 1.

Example 2

The iron powder was added so that the volume fraction of the iron oxide powder was 4%, and then subjected to a mechanical alloying treatment to produce an alloy powder according to Example 2.

Comparative Example 1

The iron powder was added so that the volume fraction of the iron oxide powder was 0.3%, and then subjected to a mechanical alloying treatment to produce an alloy powder according to Comparative Example 1. [

Comparative Example 2

The iron powder was added so that the volume fraction of the iron oxide powder was 8%, and then subjected to mechanical alloying treatment to produce an alloy powder according to Example 1.

The mechanical alloying process was a vibration ball mill. In the mechanical alloying treatment, 2.5 liters of a steel ball having a diameter of 10 mm was filled in an inner volume of 5 liter container, and a powder mixture of iron powder and iron oxide powder was filled to about 2.5 kg , An amplitude of 10 mm and a frequency of 1000 rpm for 1 hour.

In order to observe the internal microstructure of the alloy powder after the mechanical alloying treatment, 5 g of the alloy powder according to the examples and the comparative examples were sampled to prepare a tissue test specimen. The cross section of the powder was Nital etched and examined by scanning electron microscope. As a result of histological examination of the cross section of the powder, a plate having a multilayered plate structure was measured to have a plate thickness of 0.08 to 0.3 μm, and the size of the metal compound powder was measured to be about 0.1 μm. Although the amount of iron oxide added varies according to the examples and the comparative examples, the cross-sectional structures of the alloy powders are all similar.

In order to examine the powder characteristics of the alloy powder after the mechanical alloying treatment, 20 g of the alloy powder according to the examples and the comparative examples were sampled and the apparent density was measured by a Hall flowmeter tester. The average particle diameter was measured using a laser scattering method particle size analyzer, Were measured with a Ro-Tap sieve shaker classification tester. As shown in Table 1, the powder characteristics of the alloy powders were similar regardless of the amounts of iron oxide added according to Examples and Comparative Examples.

division Volume fraction of added iron oxide Apparent density
(g / cm ³⁾ powder
Average particle diameter
(μm) 10μm or less
Powder fraction
(%) Example 1 One% 3.32 12.4 54 Example 2 4% 3.26 14.2 55 Comparative Example 1 0.3% 3.17 15.6 53 Comparative Example 2 8% 3.23 13.8 56

To investigate the increase in crystallographic defects in the mechanically alloyed powders, synchrotron radiation XRD tests were carried out at the synchrotron radiation facility in Pohang, Gyeongbuk, Korea. In both the Examples and Comparative Examples, the (200) peak width of the powder before and after the mechanical alloying treatment was about 10 times peak broadening. This is a result of a significant increase in crystallographic defects in the mechanical alloying treatment powder.

In order to examine the performance of the sintered body (binder) of the alloy powder of the present invention, the mechanically alloyed alloy powder was subjected to hot press sintering at 825 ° C for 5 minutes according to the examples and comparative examples. To measure the mechanical properties of the binder, a cutting tip was prepared using only mechanically alloyed alloy powders without the addition of diamond particles, and the cutting tip dimensions were the same as the actual saw blade cutting tip dimensions. It can affect the porosity, hardness and strength of micropores of size 2μm or less which can affect the relative density, hardness, fractions of iron oxide powder (metal compound powder) The ferrite grain size was measured by image analysis on a scanning microscope. The relative density was measured with a density meter, the hardness with a Rockwell hardness tester, and the transverse rupture strength with a 3 point bending test with an Instron tester. As shown in Table 2, according to Example 1 and Example 2, when the addition amount of iron oxide was 1% and 4%, both hardness, resistance to abutment and relative density were satisfactory. On the other hand, when the amounts of iron oxide added were 0.3% and 8% according to Comparative Example 1 and Comparative Example 2, the hardness, the resistance to abutment and the relative density were low. On the other hand, as a result of microscopic examination of the binder, micropores were not distributed in all of Examples and Comparative Examples.

division Added iron oxide fraction
(volume%) Ferrite grain size
(μm) Pore fraction less than 2μm
(volume%) Relative density
(%) Hardness
(HRB) Anti-radiation
(MPa) Example 1 One% 1.95 0 97.2 97 1403 Example 2 4% 1.92 0 98.0 101 1477 Comparative Example 1 0.3% 2.48 0 96.4 83 1011 Comparative Example 2 8% 1.80 0 95.6 99 935

As described above, although the amount of added iron oxide differs according to the examples and the comparative examples, the internal structure and the powder characteristics were measured to be similar to each other in the state of the mechanically alloyed alloy powder. However, as shown in Table 2, The binder prepared by using the alloy powder having an added amount of iron oxide of 0.5 to 5.0% by volume in accordance with an embodiment of the present invention is preferably a binder prepared using an alloy powder having an addition amount of iron oxide of less than 0.5% by volume and an addition amount of more than 5.0% As a result, it can be confirmed that the film has remarkably excellent characteristics. In other words, it can be confirmed that controlling the addition amount of the metal compound powder to 0.5 to 5.0% by volume in the iron powder is an effective method for producing a binder having improved properties.

In order to confirm the effect of mechanical alloying treatment on sinterability, mechanical alloying treatment and iron powder not subjected to mechanical alloying treatment were sintered and mechanical properties of binding materials were compared. The iron powder used in the mechanical alloying treatment was a commercially available powdered iron powder, sponge iron powder and carbonyl iron powder. (Powder size: 45 μm or less) manufactured by Hoganas, MH300 (powder size: 45 μm or less) manufactured by Hoganas, and carbonyl iron powder, CN (powder size: 8 μm or less) Respectively.

Example 3

The volume fraction of the iron oxide powder was added to the water-jet iron powder so that the volume fraction became 1%, and then the alloy powder was mechanically alloyed to prepare the alloy powder according to Example 3 and sintered at a sintering temperature of 825 ° C for 5 minutes.

Comparative Example 3

The iron oxide powders were added so that the volume fraction of the iron oxide powder was 1%, and then the mixture was simply mixed using a tumbler mixer without mechanical alloying treatment to prepare a powder according to Comparative Example 3. Thereafter, sintering was performed at a sintering temperature of 825 ° C for 5 minutes by hot pressing.

Comparative Example 4

The sponge iron powder was added so that the volume fraction of the iron oxide powder was 1%, and then the mixture was simply mixed using a tumbler mixer without mechanical alloying treatment to prepare a powder according to Comparative Example 4. [ Thereafter, sintering was performed at a sintering temperature of 825 ° C for 5 minutes by hot pressing.

Comparative Example 5

The carbonyl iron powder was added so that the volume fraction of the iron oxide powder was 1%, and then the mixture was simply mixed using a turbuler without a mechanical alloying treatment to prepare a powder according to Comparative Example 5. Thereafter, sintering was performed at a sintering temperature of 825 ° C for 5 minutes by hot pressing.

As shown in Table 3 below, according to Example 3, the iron powder subjected to the mechanical alloying treatment exhibited excellent relative density, hardness, and resistance. On the other hand, according to Comparative Examples 3 to 5, iron powder not subjected to the mechanical alloying treatment was measured to have remarkably low mechanical properties.

division Iron powder type Whether mechanical alloying treatment Relative density
(%) Hardness
(HRB) Anti-radiation
MPa) Example 3 Water jet powder practice 97.2 97 1403 Comparative Example 3 Water jet powder Absenteeism 92.7 22 455 Comparative Example 4 Sponge iron powder Absenteeism 92.9 31 497 Comparative Example 5 Carbonyl powder Absenteeism 93.4 50 626

Manufacturing diamond cutting tools according to embodiments

According to Example 1 and Example 3, a cutting tip for a diamond tool was produced by using an alloy powder obtained by adding 1% iron oxide powder into iron powder and mechanically alloying the alloy powder. Specifically, the alloy powder, 2 wt% of paraffin wax and powder of diamond particles were mixed and then cold-formed and sintered at 825 ° C by hot pressing to prepare a cutting tip.

The prepared cutting tip was laser welded to a steel core to produce 10 pieces of 24 inch saw blades. The diamond particles used were MBS-970K, 30/40 mesh, and the volume fraction was 6.8%.

Production of Diamond Cutting Tool According to Comparative Example

10% WC powder was added as a main component to cobalt powder (Umicore product name: Extra fine, powder size: 1 to 3 μm), and then mixed and sintered to obtain a comparative 24-inch saw blade Respectively.

Comparison of performance of diamond cutting tools according to Examples and Comparative Examples

Table 4 below shows the results of the wet cutting test of cured concrete using saw blades according to the examples and comparative examples prepared by the above-mentioned method. The cutting test was carried out using a TARGET 65HP cutting machine. The cutting depth was 70 mm and the cutting length was 500 m. The cutting index and the life index were calculated by measuring the cutting time and the height of the worn cutting tip under the cutting conditions described above, respectively.

As can be seen from Table 4, the saw blade according to the embodiment is significantly superior to the blade according to the comparative example in cutting index and life span index. In order to examine the quality deviation of the saw blade according to the embodiment, the maximum value and the minimum value of the cutting index and the life index of 10 saw blade were shown. The range of variation of the maximum value and the minimum value of the saw blade according to the embodiment is similar to that of the saw blade according to the comparative example.

division Cutting index (m ² / min) Lifetime Index (m ² / mm) Average Min / Max Average Min / Max The diamond cutting tool according to the embodiment 0.46 0.43 / 0.47 9.4 9.1 / 9.6 The diamond cutting tool according to the comparative example 0.38 0.36 / 0.40 5.6 5.3 / 5.8

Hereinafter, a method of manufacturing a diamond tool powder and a method of manufacturing a cutting tip using the low melting point metal powder according to an embodiment of the present invention will be described in detail.

(Fe ₂ O ₃ , product of Sigma-Aldrich, powder size: 1.5 μm or less) and a low melting point metal powder (product name: ASC 300 manufactured by Hoganas Co., Tin powder (Sn, product name: M-201, product of Kennametal, powder size: 12 μm or less) was prepared. According to Examples and Comparative Examples of the present invention, the volume fraction of iron oxide powder was kept constant at 1%, and the volume fraction of tin powder was varied to prepare an alloy powder by a mechanical alloying method.

Example 4

Iron powder and iron oxide powder were added so that the volume fraction of tin powder was 0.5%, and then subjected to mechanical alloying treatment to prepare an alloy powder according to Example 4.

Example 5

Iron powder and iron oxide powder were added so that the volume fraction of tin powder was 2%, and then subjected to mechanical alloying treatment to prepare an alloy powder according to Example 4.

Comparative Example 6

Iron powder and iron oxide powder were subjected to mechanical alloying treatment so that the volume fraction of tin powder was 0%, that is, without adding tin powder, to prepare an alloy powder according to Comparative Example 6.

Comparative Example 7

Iron powder and iron oxide powder were added so that the volume fraction of tin powder was 15%, and then subjected to mechanical alloying treatment to produce an alloy powder according to Comparative Example 7. [

The mechanical alloying process was a vibration ball mill. In the mechanical alloying treatment, 2.5 liters of a steel ball having a diameter of 10 mm was filled in an inner volume of 5 liter container, and a powder mixture of iron powder and iron oxide powder was filled to about 2.5 kg , An amplitude of 10 mm and a frequency of 1000 rpm for 1 hour.

The internal microstructure and powder properties of the alloy powder after the mechanical alloying treatment were analyzed in the same manner as in Examples 1 to 2, and the analysis results were also similar. The internal microstructure and powder properties of the alloy powders showed similar results despite the difference in the amount of low melting point metal added.

In order to examine the performance of the sintered body (binder) of the low-melting-point metal-added alloy powder of the present invention, diamond particles were prepared in accordance with Examples 4 and 5 and Comparative Examples 6 and 7, Hot press sintering was performed for 5 minutes. In order to investigate the change of abrasive properties, which is most affected by the addition amount of low melting point metal powder, dry sliding wear test using pin on disk method was applied to binders. The abrasion test conditions were a glass bead containing 83% SiO ₂ , a load stress of 10 Newton, a sliding speed of 0.37 m / sec, and a sliding distance of 600 m.

As can be seen from Table 5, in Examples 4 and 5, in which the amount of tin added as a low-melting metal was 0.01 to 10% by volume in accordance with the present invention, the friction coefficients (μ) 0.35, and 0.36, respectively. On the other hand, the friction coefficient of Comparative Example 6 in which the low melting point metal was not added and Comparative Example 7 in which the low melting point metal content was 15%, which were comparative examples of the present invention, were 0.65 and 0.17, respectively. The lowering of the coefficient of friction as the amount of the low melting point metal is increased as the amount of the low melting point metal is increased is because the binding force between the grains to be abraded and peeled off of the binder is lowered so that the concentration of the low melting point metal around the grain boundaries, It can be judged that it is formed higher. For reference, the friction coefficient of the binder prepared by sintering 100% cobalt powder was 0.33, which was similar to that of Examples 4 and 5 in which the amount of the low-melting metal added in the Examples of the present invention was in the range of 0.01 to 10% Respectively.

division Added
Iron oxide fraction
(volume%) Added
Tin (Sn) metal
(volume %) Binding
Coefficient of friction
(μ) Example 4 One% 0.5 0.35 Example 5 One% 2 0.36 Comparative Example 6 One% 0 0.65 Comparative Example 7 One% 15 0.17

Manufacturing diamond cutting tools according to embodiments

According to Example 5, a cutting tip for a diamond tool was produced using an alloy powder obtained by mechanically alloying 1% iron oxide powder and 2% tin powder in iron powder. Specifically, the alloy powder, 2 wt% of paraffin wax and powder of diamond particles were mixed and then cold-formed and sintered at 825 ° C by hot pressing to prepare a cutting tip.

The prepared cutting tip was laser welded to a steel core to produce 10 pieces of 9 inch saw blades. The diamond particles used were MBS-970K, 30/40 mesh diamonds, and a volume fraction of 2.8%.

Production of Diamond Cutting Tool According to Comparative Example

10 pieces of comparative 9 inch saw blades were prepared by mixing and sintering the cobalt powder (Umicore product name: Extra fine, powder size: 1 ~ 3 μm) 100%.

Comparison of performance of diamond cutting tools according to Examples and Comparative Examples

Granite was subjected to a dry cutting test using a saw blade according to Examples and Comparative Examples prepared by the above-described method, and the results are shown in Table 6 below. BOSCH 2.7HP cutting machine was used for the cutting test. The cutting depth was 20mm and the cutting length was cut 200 times in 30cm increments. The cutting index and the life index were calculated by measuring the cutting time and the height of the worn cutting tip under the cutting conditions described above, respectively.

As can be seen from Table 6, the saw blades according to the embodiments are superior to the blades according to the comparative example in both the cutting index and the life index. In order to examine the quality deviation of the saw blade according to the embodiment, the maximum value and the minimum value of the cutting index and the life index of 10 saw blade were shown. The range of variation of the maximum value and the minimum value of the saw blade according to the embodiment is similar to that of the saw blade according to the comparative example.

division Cutting index (cm ² / min) Lifetime Index (m ² / mm) Average Min / Max Average Min / Max The diamond cutting tool according to the embodiment 405 396/413 3.9 3.7 / 4.0 The diamond cutting tool according to the comparative example 341 330/355 1.3 1.2 / 1.4

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the scope of the present invention is not limited to the disclosed exemplary embodiments. It will also be appreciated that many modifications and variations will be apparent to those skilled in the art without departing from the scope of the invention.

110: Plate structure
120: metal compound powder
210: substrate
220: Cutting tip
222: binder
224: diamond particles

Claims (6)

Preparing iron powder and metal compound powder containing carbon; And
Mixing the iron powder and the metal compound powder and then subjecting the mixture to a mechanical alloying treatment to produce an alloy powder,
The alloy powder includes a layered plate-like structure formed of iron contained in the iron powder, and a powder of the metal compound interposed between the plate-shaped structures, and having crystal defects in the plate-shaped structure Wherein the diamond powder is a diamond powder.
The method according to claim 1,
Preparing a low melting point metal powder having a melting point lower than that of iron,
Wherein the low melting point metal powder is mechanically alloyed together with the iron powder and the metal compound powder.
The method according to claim 1,
Wherein the mechanical alloying treatment is performed in air or in an inert gas atmosphere by any one of a vibrating ball mill, a streamlined ball mill, a cylindrical ball mill, or a centrifugal ball mill.
A method for manufacturing a diamond tool, comprising the steps of: preparing a powder for a diamond tool according to any one of claims 1 to 3; And
Mixing and sintering the powder for diamond tool and the powder of diamond particles to produce a cutting tip composed of a binder and diamond particles,
Wherein the metal compound powder does not have pores in the binder at the inside of the cutting tip.
A method for manufacturing a diamond tool, comprising: preparing a powder for a diamond tool according to claim 2; And
Mixing and sintering the powder for diamond tool and the powder of diamond particles to produce a cutting tip composed of a binder and diamond particles,
Wherein a content of the low melting point metal in the metal compound powder and a portion of the binder adjacent to grain boundaries in the cutting tip is higher than a content of the low melting point metal in the binder matrix.
The method according to claim 4 or 5,
Wherein the powder for diamond tool and the powder of diamond particles are sintered at a temperature of 750 to 900 占 폚, in air or in an inert gas atmosphere, or in a reduced pressure atmosphere.

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