JP2002283244A - Finishing grinding wheel and method of manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a homogeneous and inexpensive finishing grinding wheel causing no crack, and a manufacturing method therefor. SOLUTION: This finishing grinding wheel is composed of a sintered body of a silica abrasive grain. This finishing grinding wheel has a water absorption rate of 2% or less, porosity of 4% or less, and scratch hardness of 0.1 to 0.15 N (10 to 15 gf). Here, the scratch hardness expresses a load required for forming a scratch streak having a width of 0.01 mm on the surface. This finishing grinding wheel is manufactured by being quenched up to a temperature of 100 deg.C or less within 5 hours after performing a baking process by holding a mold within 30 min at a baking temperature of 1,000 to 1,500 deg.C after being molded into a prescribed shape by adding superfine amorphous silica powder having the average particle size of 0.02 to 0.1 μm to the silica abrasive grain having the average particle size of 2 to 10 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to, for example, a mold,
The present invention relates to a finishing whetstone used in a final finishing stage of a machined metal surface after grinding and polishing of a machine tool surface plate, a medical knife, a cutting tool, and the like, and a method of manufacturing the same.

[0002]

2. Description of the Related Art A slight turbulence of a so-called "burr" is generated on a machined metal surface of a die, a machine tool surface plate, a medical knife, a cutting tool or the like after grinding and polishing.
In order to remove this "burr", a final finish polishing step using a natural grindstone has conventionally been performed. As the natural whetstone, a so-called alkane whetstone mined in the Alkansas region of the United States is used, and it is extremely difficult to perform a sufficiently satisfactory final finishing process with a natural whetstone mined in other production areas. . The alkane grindstone is composed of a polycrystal of α-quartz (silicon oxide) of about 5 μm.

[0003]

However, at the present time, the alkane whetstones are already being depleted of good quality, and the alkane whetstones are often cut out from rough ore containing cracks. Therefore, it is sold with a crack inside, and there is a problem that it is damaged by falling or collapsed by boiling water. Furthermore, it is extremely difficult to cut out a large chunk of alkane grinding stone (for example, a rectangular solid mass of 200 × 50 × 25 mm) without cracking, and the alkane grinding stone is most suitable as a grinding stone for final finishing. Furthermore, it is sold at extremely high prices due to the balance between supply and demand.

[0004] The present invention has been made by focusing on the problems existing in the prior art as described above. An object of the present invention is to provide a uniform and inexpensive finishing whetstone free of cracks and a method of manufacturing the same.

[0005]

In order to achieve the above object, a finishing whetstone according to the first aspect of the present invention is formed of a sintered body of silica abrasive grains and used for finishing a metal surface. It is characterized by the following.

The finishing whetstone according to the second aspect of the present invention
The invention according to claim 1, wherein the water absorption is 2% or less, the porosity is 4% or less, and the scratch hardness is 0.1 to 0.15N. However, the scratch hardness represents a load required to form a scratch with a width of 0.01 mm on the surface.

The finishing whetstone according to the third aspect of the present invention is
3. The sintering treatment according to claim 1 or 2, wherein the ultrafine amorphous silica powder is added to the silica abrasive grains to form a predetermined shape, and then held at a sintering temperature of 1000 to 1500 ° C. for 30 minutes or less. And then rapidly cooling to a temperature of 100 ° C. or less within 5 hours.

According to a fourth aspect of the present invention, there is provided a method for producing a finishing whetstone, comprising: an ultrafine amorphous silica powder having an average particle diameter of 0.02 to 0.1 μm and a silica abrasive having an average particle diameter of 2 to 10 μm. To form a predetermined shape, and then 1000 to 150
After the sintering treatment is performed while maintaining the sintering temperature at 0 ° C. for 30 minutes or less, the quenching is performed to a temperature of 100 ° C. or less within 5 hours.

[0009]

Embodiments of the present invention will be described below in detail. The finishing whetstone of the embodiment is constituted only by a sintered body of silica abrasive grains. As a physical property value of this finishing whetstone, the water absorption rate is 2% or less,
Porosity of 4% or less and scratch hardness of 0.1 to 0.15N
(10 to 15 gf). The scratch hardness represents a load required to form a scratch with a width of 0.01 mm when the surface is scratched at a diamond point. And since the physical property value is a value very similar to the alkane whetstone which is optimal for metal surface finishing, a mold, a machine tool surface plate,
Ideal for final polishing of metal surfaces such as medical scalpels and cutting tools. In addition, in the final finishing polishing of the metal surface, very good results can be obtained similarly to the case of the alkane grindstone.

Further, the water absorption is more preferably 0.1 to 2%, further preferably 0.5 to 1%. If the water absorption is less than 0.1%, the sintered body becomes too hard and slips with the material to be polished, and does not function as a finishing whetstone. Conversely, if it exceeds 2%, it is not suitable for final finishing polishing because the density of the finishing whetstone is insufficient. Further, the porosity is more preferably 0.5 to 4%, further preferably 0.5 to 2%.
%. If the porosity is less than 0.5%, the sintered body becomes too hard and slips with the material to be polished, and does not function as a finishing whetstone. On the other hand, if it exceeds 4%, scratches may be formed on the surface of the material to be polished (metal) during polishing due to internal pores.

On the other hand, the scratch hardness is 0.1 N (10 g
If the value is less than f), scratches are likely to be formed on the surface of the workpiece during polishing. Conversely, 0.15N (15g
When the value exceeds f), the surface of the grindstone has a small amount of irregularities and has a high hardness, so that it slips during polishing and cannot be used as a grindstone. The Vickers hardness is 150 to 350 for the same reason as the scratch hardness.
It is preferably within the range of Hv.

The shrinkage of the finishing whetstone is preferably at least 7%, more preferably 7 to 9%. Further, the bulk density of the finishing whetstone is preferably 2.1.
0 g / cm ³ or more, more preferably 2.1 to 2.7 g / cm ³
cm ³ . When the shrinkage is less than 7% and when the bulk density is less than 2.1 g / cm ³ , the water absorption is 2
% Or porosity exceeds 4%.

In producing this finishing whetstone, first, a mixed powder obtained by mixing silica abrasive grains (powder) and ultrafine amorphous silica powder is prepared, and then a slurry cast molding or a pressure molding is performed. To produce a molded body which is formed into a predetermined shape and dried. In addition, as the molding method, it is more preferable to use a slip casting method because a molded article having a complicated shape can be easily molded. Further, the slurry casting method is also excellent in productivity in small-quantity production. Next, after performing the baking treatment while holding the molded body at a baking temperature of 1000 to 1500 ° C. for 30 minutes or less,
It is obtained by performing a quenching treatment of rapidly cooling to a temperature of 100 ° C. or less within an hour.

The silica abrasive is a main component constituting a finishing whetstone, and quartz powder, fused silica powder or quartz glass powder is preferably used. The average particle size of the silica abrasive grains is preferably 2 to 10 μm, and more preferably 3 to 8 μm. When the average particle diameter of the silica abrasive grains is less than 2 μm, the particles cannot function as finishing abrasive grains because the particles are small. Conversely, if it exceeds 10 μm, a dense sintered body cannot be obtained, and cracks are likely to occur. When quartz powder is used as the silica abrasive, the content of the quartz powder in the mixed powder is preferably set to 0 to 50% by weight. If the content of the quartz powder exceeds 50% by weight, densification during sintering does not easily proceed, and cracks tend to occur due to a difference in coefficient of thermal expansion due to phase transition.

The ultrafine amorphous silica powder is blended in order to increase the density and sinterability of the finishing whetstone. As the ultrafine amorphous silica powder, a silica gel powder is preferably used. The average particle diameter of the ultrafine amorphous silica powder is preferably 0.02 to 0.1 μm. The average particle diameter of the ultrafine amorphous silica powder is 0.0
When it is less than 2 μm, it is extremely fine and it is difficult to produce a powder, so that the price is high. Conversely, 0.1μ
If it exceeds m, the densities of the compact and the finishing whetstone cannot be sufficiently increased. The content of the ultrafine amorphous silica powder in the mixed powder is preferably 1
0 to 50% by weight, more preferably 10 to 30% by weight. The content of this ultrafine amorphous silica powder is 10% by weight.
If it is less than 3, high moldability cannot be obtained during molding. On the other hand, if it exceeds 50% by weight, a dense sintered body cannot be produced. At this time, the moldability is low and the possibility of cracking during sintering is also high.

In the slurry casting, a slurry (slurry) is prepared by adding an appropriate amount of water to the mixed powder, and then the slurry is poured into a porous mold such as a gypsum mold or a resin mold to be solidified. It is. As the porous mold, it is more preferable to use a gypsum mold because the cost can be easily suppressed and the productivity in multi-product small-quantity production is excellent. Furthermore, after pouring the slurry into the porous mold, it is more preferable to apply vibration to the porous mold or increase the pressure in the porous mold to improve the density of the molded body. . In particular, by increasing the pressure in the porous mold, it is possible to easily mold a molded article having a thickness.

Furthermore, in this slurry casting,
In order to uniformly disperse the mixed powder in the slurry,
It is possible to add a dispersant that disappears at a firing temperature of 1000-1500C. As the dispersant, polymer dispersants such as polycarboxylates and polyacrylates, amines, water glass and the like are suitably used. The amount of the dispersant added to the mixed powder is preferably 1% by weight or less, more preferably 0.5% by weight or less. If the amount of the dispersant exceeds 1% by weight, the dispersibility may be reduced due to the excessive amount of the dispersant in the mixed powder.

Further, in this slurry cast molding, in order to improve shape retention and raw workability after molding, 100
It is also possible to add an organic binder which disappears at a firing temperature of 0 to 1500 ° C. An acrylic binder is preferably used as the organic binder. The amount of the organic binder added to the mixed powder is preferably 7% by weight or less, more preferably 5% by weight or less. When the addition amount of the organic binder exceeds 7% by weight, the amount of water from the binder increases, so that the inlay in the porous mold is delayed, and it is difficult to form a thick molded body. Could be.

In the pressure molding, after adding an organic binder and a solvent (such as water) to the slurry prepared in the above-mentioned slurry casting, the granules for pressure molding prepared by drying with a spray drier are used. , Uniaxial press forming, isostatic pressing (CIP) forming or hot pressing (H
P) This is a method of molding using molding. As the organic binder, polyvinyl alcohol or cellulose is preferably used.

In the firing treatment, the molded body formed into a predetermined shape by the above-mentioned slurry casting or pressure molding is subjected to 1000
Sintering temperature of ~ 1500C, preferably 1200-140
This is a process of firing at a firing temperature of 0 ° C. When the firing temperature is lower than 1000 ° C., the compact cannot be sintered and sufficiently densified. On the other hand, when the temperature exceeds 1500 ° C., the density of the finishing whetstone cannot be sufficiently increased because the inside of the molded body may foam.

Further, the firing temperature (1000 to 150)
0 ° C.) is configured to be maintained within 30 minutes. If the holding time exceeds 30 minutes, cristobalite grows inside due to crystallization of the amorphous silica, and the difference in the coefficient of thermal expansion between the amorphous portion and the crystalline portion indicates that the inside of the sintered body has Strain occurs and cracks easily occur. The quenching process for lowering the temperature in the firing furnace may be performed immediately after the temperature in the firing furnace for firing the formed body reaches 1000 ° C.

The quenching treatment is performed in the above-mentioned baking treatment.
A molded body held at a firing temperature of 00 to 1500 ° C.
This is a process of rapidly cooling to a temperature of 100 ° C. or less (almost at room temperature) within an hour, preferably within 3 hours. When the time required for cooling from the firing temperature to 100 ° C. or less exceeds 5 hours, amorphous silica is crystallized and cristobalite grows inside, and the coefficient of thermal expansion between the amorphous portion and the crystalline portion is reduced. Due to the difference, a strain is generated inside the sintered body and cracks easily occur.

In this quenching treatment, the firing temperature is reduced by 1%.
In order to ensure rapid quenching below 00 ° C.,
The firing is preferably performed by an atmosphere firing method, a vacuum firing method, a plasma firing method, a microwave firing method, a baking firing method, a hot press firing method, or the like, but the atmosphere firing method is optimal. The atmosphere in the firing furnace at this time is preferably an oxidizing atmosphere, but may be a vacuum or argon atmosphere in order to prevent oxidation of the firing furnace material.

The effects exerted by the above embodiment will be described below. -The finishing whetstone of the embodiment is constituted only by a sintered body of silica abrasive grains. This finishing whetstone is intended to eliminate the excessive demand and high price of final finishing whetstones mainly due to the depletion of alkane whetstones, which has been conventionally optimized for the final finish polishing of metal surfaces. It was developed as a result of the inventors' earnest research. This finishing whetstone has almost the same polishing performance as the alkane whetstone, and since it is easy to obtain a large amount of raw materials at low cost, it is continuously provided at low cost without fear of depletion. It is possible to Furthermore, compared to a natural alkane grindstone, it is extremely easy to manufacture homogeneously so that cracks are not formed, so that it is possible to provide a high-quality final finishing grindstone.

Further, as the physical properties of the finishing whetstone, the water absorption is 2% or less, the porosity is 4% or less, and the scratch hardness is 0.1 to 0.15 N (10 to 15 gf). The same characteristics as natural alkane whetstone can be exhibited. In particular, since the most important characteristic when using as a grindstone, scratch hardness, is a value close to that of an alkane grindstone, the final finishing of metal surfaces such as dies, machine tool surface plates, medical scalpels, and cutting tools Most suitable for polishing.

The finishing whetstone has an average particle diameter of 2 to 2.
10-μm silica abrasive with an average particle size of 0.02-0.1μ
After adding ultrafine amorphous silica powder of m and forming into a predetermined shape, holding at a firing temperature of 1000-1500 ° C. for 30 minutes or less and performing a firing treatment, rapidly cooling to a temperature of 100 ° C. or less within 5 hours It is manufactured by doing. For this reason,
A sintered body of crack-free homogeneous silica abrasive grains can be produced very easily and at low cost. Further, according to this manufacturing method, a sintered body of silica abrasive grains having a water absorption of 2% or less, a porosity of 4% or less, and a scratch hardness of 0.1 to 0.15N having physical properties in the range of Because it can be manufactured,
A grindstone for final polishing can be easily and reliably manufactured.

In general, quartz (silica) has a phase transition from α-quartz to β-quartz at 573 ° C. and various properties such as cristobalite and tridymite at a high temperature of 1000 ° C. or higher. In such a crystal transition, the coefficient of thermal expansion changes greatly, so that the possibility of cracking during cooling is extremely high, and it is almost impossible to sinter only quartz. There is also a problem that densification during sintering does not proceed.

On the other hand, as a method for obtaining a sintered body of amorphous silica, a method is mainly used in which coarse particles are formed by casting or the like and fired in steam for a short time (for example, Japanese Patent Publication No. 49-2708).
No. 3 and Japanese Patent Publication No. 1-54301) and a method of casting a particle having an average particle diameter of 2 μm or less to obtain a dense sintered body (for example, Japanese Patent Application Laid-Open No. 6-166564). . In order to use as a final finishing whetstone, the average particle diameter of the silica abrasive grains needs to be in the range of 2 to 10 μm, but when only the abrasive grains in this range are used,
There are problems such as that the density of the molded body does not increase and cracks occur after firing. Further, Japanese Patent Publication No. 1-54301 discloses a fused silica raw material 10 having an average particle diameter of 10 μm or less.
Although a method of firing 0% with dry air is disclosed, there are problems that cracks are generated in the fired body and a dense sintered body cannot be obtained.

As a result of the present inventors' intensive studies on these problems, it has been found that the combination of the particle diameters of the silica used and the cooling time after sintering greatly affect the properties of the silica sintered body. Was found. That is, when the silica used is only α-quartz, the thermal expansion coefficient greatly changes due to the phase transition, cracks occur during cooling after firing, and a good sintered body cannot be obtained. Therefore, in addition to adding amorphous powder to silica as a starting material, combining two or more powders having different particle diameters in combination, and conducting trial and error while changing the conditions of molding, drying and firing in various ways. went. As a result, silica abrasive particles having an average particle size of 2 to 10 μm and an average particle size of 0.02 to
After blending, molding, drying and firing at a high temperature of 0.1 μm ultrafine amorphous silica, it was found that the amorphous powder was bonded and sintered by cooling to 100 ° C. or less within 5 hours. . In addition, if it cools over 5 hours after firing, cristobalite crystals grow inside the sintered body,
It has also been found that cracks tend to occur in the sintered body due to the difference in the thermal expansion coefficient between the amorphous body and the cristobalite crystal.

[0030]

EXAMPLES Examples and comparative examples which embody the above embodiment will be described below. (Example 1) Average particle size 3μ
80% by weight of fused silica powder having an average particle size of 0.07
A slurry was prepared by adding 25% by weight of water to 75% by weight of a mixed powder obtained by weighing 20% by weight of an amorphous silica powder having a particle size of 20 μm and mixing with a zirconia ball for 1 day. The viscosity of the prepared slurry was measured using a rotational viscometer B type N manufactured by Shibaura System Co., Ltd.
o. The measurement was performed at a measurement temperature of 25 ° C. using a three rotor. As a result, the viscosity of the slurry was 342 mPa · s
Met. The pH was 7.5.

Next, the slurry was placed in a gypsum mold (100 × 50).
× 14mm), and after performing solid casting of the slurry, the molded body was baked in an atmosphere firing furnace (PHI manufactured by Shimadzu Corporation).
VSG), a baking treatment was performed at a baking temperature of 1250 ° C. for 20 minutes in an argon atmosphere to produce a finishing whetstone. At this time, the temperature rise time in the firing furnace was set to 2 hours 5 minutes to 2 hours 10 minutes, and from 1250 ° C to 1 hour.
The cooling time to 00 ° C. was 3 hours.

(Example 2) A finishing whetstone was manufactured in the same manner as in Example 1 except that the firing temperature in the above-mentioned firing treatment was 1300 ° C.

Example 3 70% by weight of fused silica powder having an average particle diameter of 3 μm, 10% by weight of fused silica powder having an average particle diameter of 7 μm, and 20% by weight of amorphous silica powder having an average particle diameter of 0.07 μm were weighed. 81% by weight of mixed powder in water 19
% By weight and mixed with a zirconia ball for 1 day to prepare a slurry. When the viscosity of the prepared slurry was measured in the same manner as in Example 1, it was 410 mPa · s. The pH was 8.1. Next, a finishing whetstone was manufactured in the same manner as in Example 1 using the same slurry.

Example 4 60% by weight of fused silica powder having an average particle diameter of 3 μm, 20% by weight of fused silica powder having an average particle diameter of 7 μm, and 20% by weight of amorphous silica powder having an average particle diameter of 0.07 μm were weighed. 81% by weight of mixed powder in water 19
% By weight and mixed with a zirconia ball for 1 day to prepare a slurry. When the viscosity of the prepared slurry was measured in the same manner as in Example 1 above, it was 405 mPa · s. The pH was 8.3. Next, a finishing whetstone was manufactured in the same manner as in Example 1 using the same slurry.

Example 5 70% by weight of fused silica powder having an average particle diameter of 3 μm, 10% by weight of quartz powder having an average particle diameter of 6 μm, and amorphous silica powder 20 having an average particle diameter of 0.07 μm
19% by weight of water was added to 81% by weight of the mixed powder weighed at% by weight, and mixed with a zirconia ball for 1 day to prepare a slurry. The viscosity of the prepared slurry was measured in Example 1 above.
Was 226 mPa · s.
The pH was 8.1. Next, a finishing whetstone was manufactured in the same manner as in Example 1 using the same slurry.

Example 6 60% by weight of fused silica powder having an average particle diameter of 3 μm, 20% by weight of quartz powder having an average particle diameter of 6 μm, and amorphous silica powder 20 having an average particle diameter of 0.07 μm
19% by weight of water was added to 81% by weight of the mixed powder weighed at% by weight, and mixed with a zirconia ball for 1 day to prepare a slurry. The viscosity of the prepared slurry was measured in Example 1 above.
Was 163 mPa · s.
The pH was 8.3. Next, a finishing whetstone was manufactured in the same manner as in Example 1 using the same slurry.

Comparative Example 1 22% by weight of water was weighed in 78% by weight of fused silica powder having an average particle diameter of 0.6 μm, and mixed with zirconia balls for 1 day to prepare a slurry.
When the viscosity of the prepared slurry was measured in the same manner as in Example 1, it was 226 mPa · s. The pH was 8.1. Next, the slurry was placed in a plaster mold (65 × 6
5 × 7 mm), and after performing solid casting of the slurry, the molded body is placed in an atmosphere firing furnace (PVSG).
The finishing whetstone was manufactured by performing a baking treatment at a baking temperature of 1250 ° C. for 20 minutes in an argon atmosphere. At this time, the heating time in the firing furnace was 2 hours and 5 minutes, and the cooling time from 1250 ° C. to 100 ° C. was 3 hours.

<Characteristics Test of Silica Sintered Body> Examples 1 to 6
For the finishing whetstone of Comparative Example 1, the shrinkage (%), the bulk density (g / cm ³ ), the water absorption (%), the porosity (%), the scratch hardness 1 ( gf), scratch hardness 2 (mm ² / kgf) and Vickers hardness (Hv) were measured. In addition, for natural whetstones (alkane whetstones) produced in the Alkansas region and commercially available quartz glass plates,
Water absorption, porosity, scratch hardness 1, scratch hardness 2, and Vickers hardness were measured. Tables 1 and 2 show the results and the judgment on the appearance of each sintered body.

The scratch hardness was measured using a precision scratch hardness tester (manufactured by Marubishi Kagaku Seisakusho Co., Ltd.) while gradually increasing the load applied to the diamond point. It was formed, and the relationship between the scratch width and the load was measured and determined by plotting on the graph shown in FIG. The scratch hardness 1 (gf) in the table indicates the load required to form a scratch with a width of 0.01 mm obtained from the graph of FIG. 1, and the scratch hardness 2 (mm ² / kg)
f) was determined from the slope of the straight line in the graph of FIG. Further, Table 2 shows a value obtained by converting the unit of the scratch hardness 1 into (N) and a value obtained by converting the unit of the scratch hardness 2 into (mm ² / N). The Vickers hardness was measured using a MVK-H2 measuring device manufactured by Akashi Co. while applying a load of 2 kgf (19.6 N) to the diamond point.

[0040]

[Table 1]

[0041]

[Table 2] As a result, it was confirmed that the finishing whetstones of Examples 1 to 6 had physical properties very similar to those of the alkane whetstones. Further, the finishing whetstone of Comparative Example 1 was partially cracked. Further, for the finishing whetstones of Examples 1 to 6, the fired sintered body was cut and polished to 70 × 35 × 1.
After processing to 0 mm, the blade portion of the medical knife was actually subjected to final finish polishing to evaluate the grindstone characteristics. As a result, it was confirmed that the same polishing characteristics as those of the alkane grindstone were obtained.

On the other hand, when the crystal structures of the finishing whetstones and alkane whetstones of Examples 1 to 6 were examined by an X-ray diffraction apparatus, the finishing whetstones of Examples 1 to 4 were in an amorphous state.
Α quartz and cristobalite were identified from the finishing whetstones of Examples 5 and 6, and α quartz was identified as the alkane whetstone. When the fracture surface was observed with a scanning electron microscope, it was also found that each of the fractured structures had a granularity of about 3 to 7 μm. (In the sample mixed with the quartz powder, it is considered that the quartz partially transformed into cristobalite.) Further, the technical idea grasped from the above embodiment will be described below.

The ultrafine amorphous silica powder is added in a content of 10 to 50% by weight based on the total weight of the silica abrasive grains and the ultrafine amorphous silica powder. Item 5. The method for producing a finishing whetstone according to Item 4. With such a configuration, the formability at the time of molding can be easily improved, and a dense sintered body can be easily manufactured.

The silica abrasive has an average particle diameter of 2
5. The method for producing a finishing whetstone according to claim 4, wherein a quartz powder of 10 to 10 [mu] m is used and the content is 50% by weight or less. In such a configuration, the α-quartz particles remain in the sintered body, and can have a structure similar to that of a natural grindstone.

[0045]

As described above in detail, according to the present invention, the following effects can be obtained. According to the finishing whetstone of the invention described in claims 1 to 3, a uniform finishing whetstone free of cracks can be provided at low cost.

According to the method for manufacturing a finishing whetstone according to the fourth aspect of the present invention, a uniform finishing whetstone free of cracks can be manufactured at low cost.

[Brief description of the drawings]

FIG. 1 is a graph showing measurement results of scratch hardness in a characteristic test of an example.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Eihiro Todaka 4-4-2, Shimozawa-machi, Tajimi-shi, Gifu (72) Inventor Hisanori Yokoyama 3-210, Narikiyo-cho, Kakamigahara-shi, Gifu (72) Inventor Kato Nun Hisashi 156-16-1 Yamada-cho, Mizunami-shi, Gifu (72) Inventor Hideho Yoshida 2-16-16, Hakusan-cho, Kasugai-shi, Aichi F-term (reference) 3C063 AA02 AB07 BA02 BB01 BB07 BC01 BC05 CC04 EE28 FF23

Claims (4)

[Claims] 1. A finishing whetstone comprising a sintered body of silica abrasive grains and used for finishing a metal surface. 2. The finishing whetstone according to claim 1, wherein a water absorption is 2% or less, a porosity is 4% or less, and a scratch hardness is 0.1 to 0.15N. However, the scratch hardness represents a load required to form a scratch with a width of 0.01 mm on the surface. 3. A method in which ultrafine amorphous silica powder is added to silica abrasive grains to form a predetermined shape, followed by performing a baking treatment at a baking temperature of 1000 to 1500 ° C. for 30 minutes or less,
The finishing whetstone according to claim 1 or 2, obtained by rapidly cooling to a temperature of 100 ° C or less within 5 hours. 4. An ultrafine amorphous silica powder having an average particle size of 0.02 to 0.1 μm is added to silica abrasive particles having an average particle size of 2 to 10 μm to form a predetermined shape.
A method for producing a finishing whetstone, comprising: performing a baking treatment while maintaining the baking temperature at 500 ° C. for 30 minutes or less, and rapidly cooling to a temperature of 100 ° C. or less within 5 hours.