JP2007307701A - Rotary grinding tool excellent in rust removal and base adjustment, its manufacturing method and rust removal and base adjustment method using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary grinding tool which efficiently and effectively removes thick rust and fastened rust formed on a steel structure having a large area of a bridge, etc., an iron manufacturing process intermediate product, etc. in storage at low cost, while securing high workability and safety, and which carries out base adjustment of a steel material surface. <P>SOLUTION: The rotary grinding tool excellent in rust removal and base adjustment is constituted so that hard particles exceeding Moh's hardness 9 to be surface density of more than 20 pieces/cm2 are brazed and joined on a part or the whole of a grinding surface of a metal rotating board, average H is more than 300μm, and average H/D is more than 0.3 when height of a projected part constituted by these particles and a wax material is specified as H and a diameter of the projected part is specified as D, and an average exposed surface area ratio is more than 10% when the exposed surface area ratio of the hard particles exposed from the surface of the wax material is found by using virtual balls externally contacting with the hard particles of the projected part. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

TECHNICAL FIELD The present invention relates to coating ground treatment of steel structures such as civil engineering, architecture, plant, shipbuilding, and in particular, rust for efficiently painting ground coating of a site where thick rust such as layered rust and scaly rust is generated. Involved in removal and substrate preparation techniques. Further, the present invention relates to a technique for efficiently removing thick rust formed on the surface of a slab stored for a long time in a steelmaking hot rolling process.
Specifically, the present invention relates to a rotary grinding tool excellent in rust removal and substrate adjustment, a manufacturing method thereof, and a rust removal and substrate adjustment method using the same.

  Steel structures such as civil engineering, architecture, plant, shipbuilding, etc. cause corrosion according to the environmental conditions used. For example, onshore steel structures in areas where there is a lot of salt damage, harbor steel structures on coasts and wharves, ships, plants, etc. all have a life because their initial functions deteriorate over time due to corrosion. In order to prolong this life and use it safely and safely for many years, maintenance is required. In recent years, corrosion-resistant low alloy steels such as weathering steel having a slower corrosion rate have been used as members of these steel structures. In particular, weathering steel is used without coating when the corrosiveness of the environmental conditions to be constructed is assumed to be mild. Therefore, when the environment changes due to various reasons after construction, and the corrosivity shifts to a more severe side than expected, the corrosion rate increases, and as a result, generation of thick rust such as layered rust and scaly rust is observed. May be. Thus, when a thick rust is generated in a steel structure, a measure is required to reduce the corrosion rate of the base steel that is the cause. One example is painting. Various methods have been devised on site to remove the layered rust and scaly rust that have been generated in steel structures so far, and coating for anticorrosion. It was unexpectedly difficult. In particular, in the case of a corrosion-resistant low alloy steel such as weather-resistant steel, a dense rust having high adhesion is formed, and thus it is often difficult to remove a thick rust as a coating base treatment. In the future, the application of corrosion-resistant low-alloy steels is expected to expand beyond the bridge field where weather-resistant steel is used, so even if thick rust occurs, a method that can remove rust efficiently and effectively It is necessary to develop. There is also a need for techniques for efficiently removing thick rust formed on the surface of steel in the iron making process. For example, a large amount of steel slabs may be stored indoors or outdoors for a long period of time due to production planning. When steel slabs are stored outdoors for a long period of time, especially in coastal steelworks, etc. A thick rust may be formed under the influence of. In such a case, if the thick rust is not removed before going to the hot rolling process, the surface of the product after rolling enters wrinkles and scabs, which reduces the commercial value.

2. Description of the Related Art Conventionally, for example, a method of removing rust generated on a steel material using an alumina-based or silicon carbide-based grindstone grinder or paper grinder has been widely used. However, in the case of thick rust generated on a corrosion-resistant low alloy steel material, the hardness of alumina or silicon carbide, which is an abrasive, is lower than that of the fixed layered rust, so the rust cannot be removed and the grinder wears. For this reason, a process of removing the thick layered rust using a power tool called a jet degasser or jet chisel and removing the thin adhesive rust with the grinder must be assembled. However, even with several rust removal steps, the hardness of the adhesion rust that cannot be removed with jet chisel or jet chisel is even higher, and the grinder wears out, leading to an exposed state of the steel surface that is sufficient as a coating ground treatment. It has become difficult.
Incidentally, according to Non-Patent Document 1, any of the thick rust removing steps of the corrosion-resistant low-alloy steel material by a combination of power tools has been evaluated as insufficient as a coating base treatment. For this reason, it has been proposed as a standard to use the blast method for removing the adhesion rust. However, the general blast method is said to be difficult to use in the future due to environmental considerations because it is noisy and dust is scattered. In addition, there is a problem that the apparatus is large and expensive as compared with the processing using a power tool. As an improved blasting method, for example, there is a method called a vacuum blasting method. This method is a vacuum suction of blast particles and dust at the same time as the cleaning, but the apparatus becomes larger, resulting in an increase in processing cost. There is also a sponge blasting method using a mixture of sponge-like resin and hard particles as the abrasive, but the life of the abrasive is short, resulting in high costs.

  When considering a rust removal method to replace the blasting method, which is becoming difficult to use due to environmental considerations and responding to it, we thought that it would be better to return to the starting point and develop a power tool. An essential problem in the method of removing thick rust by a power tool is that the hardness of the abrasive is lower than that of layered rust or adhesion rust. Therefore, for example, when a test for removing a thick rust was performed using a cutting rotary tool embedded with diamond particles described in Patent Document 1, a thick rust was efficiently removed without losing the hardness of the rust. I found that I can cut. However, this is a cutting tool and does not have sufficient function to pulverize and remove thick rust at a high speed. It was judged not suitable for field work. Needless to say, it is not preferable from the viewpoint of safety to use the original cutting tool for removing the thick rust. In addition, I bought several commercially available diamond grinding tools and tried to remove thick rust. These were able to work more stably than the cutting tool described above, but because the weight of the disk was light, vibration during work could not be eliminated, and there was a problem in workability, and at the same time, the diamond surface adhering to the board surface and circumference The problem was that the thick rust could not be removed at high speed because the density was low and the entire surface of the diamond particles was covered with wax material.

  In addition, rotary grinding tools with diamond attached by electroforming are also available on the market, but they can be used to remove thick rust formed on steel structures with large areas such as bridges because of the low adhesion strength of diamond. During this process, the problem of reduced grinding ability was recognized. Other tools that could be used to remove rust were used, but none of them was satisfactory in view of workability when removing thick sticky rust on site. Further, non-patent literatures 1 and 2 that have evaluated and studied the latest technology for repair coating ground treatment show that the reliable ground treatment for repair coating must rely solely on the blast method. Up to now, there has been a power tool that removes rust with a weak adhesive strength of about 200 μm or less, but it is suitable as a base coating for coating as well as efficiently removing rust formed on steel structures with strong adhesive strength. There has never been a rotary grinding tool for removing rust and adjusting the substrate that can ensure the exposure of the steel surface.

JP-A-11-028670 Chiaki Miki, edited by Atsushi Ichikawa Modern bridge engineering The forefront of unpainted bridges and steel Published by Science and Engineering Corporation 2004.12.25 Ishikawa, K .: Preparation of foundation material, 28th steel structure painting technology debate presentation pp. 43-48, Japan Steel Structure Association October 1, 2005

  The present invention solves the above-mentioned various problems, and a rust having a strong and strong adhesion formed on a steel structure having a large area such as a bridge can be easily and quickly, efficiently and effectively, and at a low cost. Provided is a rotating grinding tool excellent in rust removal and substrate adjustment, and a manufacturing method thereof, and a rust removal and substrate adjustment method using the same, which is safe and has good workability and can perform from rust removal to steel surface exposure at once. .

The present invention has been made to solve the above-described problems, and the gist thereof is as follows.
(1) A rotary grinding tool comprising a metal rotary disk having a central mounting portion for mounting on a rotary shaft of a rotary drive device and a grinding surface composed of a grinding machine surface and a grinding peripheral surface, and grinding of the metal rotary disk Hard particles having a Mohs hardness of 9 or more are brazed and bonded to a part or all of the surface so that the surface density is 20 particles / cm ² or more. The height of the protrusion formed by the hard particles and the wax material is H. When the diameter is D, the average H is 300 μm or more, the average H / D ratio is 0.3 or more, and is exposed from the surface of the wax material using phantom spheres circumscribing the hard particles of the protrusions. A rotating grinding tool excellent in rust removal and substrate adjustment, characterized in that when the exposed surface area of hard particles is determined, the average exposed surface area ratio is 10% or more.
(2) The hard particles having a Mohs hardness of 9 or more are diamond or cubic boron nitride having an average particle diameter of 200 μm or more and 1000 μm or less, and the wax material is 0.5% by mass or more of at least one of titanium, chromium and zirconium. The rotating grind tool excellent in rust removal and substrate adjustment according to (1), characterized in that the metal turntable is made of stainless steel.
(3) A portion of the grinding surface of the metal rotating disk composed of a grinding machine surface and a grinding peripheral surface is such that the angle between the normal of the grinding machine surface and the rotation center axis is 1 ° or more and 45 ° or less. And the grinding peripheral surface has a portion where the radius of curvature of the cross section parallel to the rotation center is R1 mm or more and R10 mm or less, and the rust removal according to any one of (1) to (2), Rotary grinding tool with excellent substrate adjustment.
(4) The rust according to any one of (1) to (3), wherein an even number of cuts are provided in the center object from the circumferential part to the center part of the metal rotating disk. Rotary grinding tool with excellent removal and substrate adjustment.
(5) The rotary grinding tool excellent in rust removal and substrate adjustment according to any one of (1) to (4), wherein the metal turntable has a mass of 160 g or more.
(6) The rotating grinding tool excellent in rust removal and substrate adjustment according to any one of (1) to (5), wherein the diameter of the metal rotating disk is 50 mm or more.
(7) The average shear strength of the hard particles having a Mohs hardness of 9 or more is 20 N / particles or more, and is excellent in rust removal and substrate adjustment according to any one of (1) to (6) Rotary grinding tool.

(8) A powdered wax mixed with an organic binder is applied to the cutting surface of the metal rotating disk so as to have a thickness of 20 to 60% of the average particle diameter of the hard particles exceeding the Mohs hardness 9, and the Mohs hardness is applied thereon. Applying more than 9 hard particles to a surface density of 30 particles / cm ² or more, and holding at a temperature of 1000 ° C. to 1040 ° C. for 10 minutes to 50 minutes under a reduced pressure of 10 ⁻⁴ Torr or less. A method for producing a rotary grinding tool excellent in rust removal and substrate adjustment.

(9) A substrate adjustment method characterized by grinding a material having a Mohs hardness of less than 10 using the rotary grinding tool excellent in rust removal and substrate adjustment according to any one of (1) to (7).

  According to the present invention, it is possible to easily remove the thick rust generated in a corrosion-resistant low alloy steel material such as weathering steel, which has been considered difficult until now. In general, the blasting method has been used for coating protection for ordinary steels including anti-corrosion, but a large-scale apparatus is used, and there is a problem of dust and noise. In addition, as shown in FIG. 6, the sticking rust of nickel-based high weathering steel that has been commercialized in recent years is harder than conventional weathering steel and can be removed even by using high-cost garnet or alumina having a Mohs hardness of about 9. It has been pointed out that the problem cannot be solved. Needless to say, before blasting, it is necessary to remove the thick rust by striking with a hammer or using a vibration tool such as a jet chisel or jet chisel. In the past, it was impossible to remove the sticking rust. However, in the present invention, it is possible to remove even the very hard fixed rust formed on the nickel-based high weathering steel as shown in FIG. That is, it does not require thick rust removal by prior impact treatment, and can be removed until the metal surface is exposed at once, and according to the present invention, a large air compressor and hopper essential for blasting are not required.

  Moreover, since the load applied to the maintenance and repair work of the steel structure is greatly reduced by the present invention, it is possible to simultaneously achieve high quality repair coating and drastic cost reduction. In addition, it can effectively and effectively remove thick rust and sticking rust generated in intermediate products with various alloy compositions stored at the coastal steelworks for a long time, which is also effective in increasing production elasticity in the ironmaking process. There is. Furthermore, it is possible to efficiently grind inorganic materials such as concrete, rocks, minerals, metals, organic materials or their composites having a Mohs hardness of less than 10, so that steel structures in which various materials are used in combination. It can be applied in various fields.

Hereinafter, the present invention will be described in detail with reference to the drawings of the embodiments.
The substrate adjustment of the present invention refers to adjusting the state and form of the material surface to a desired state.
In addition, the rotary grinding tool of the present invention attaches the rotating grinding tool mounting portion to a grinding tool having a rotary drive device such as electric rotation or a rotating shaft of a grinding device and rotates it to remove rust and adjust the substrate as a coating ground treatment. Is to do. As a grinding tool or grinding device having a rotation drive device, a disk grinder is generally used. In addition, a movable grinding device provided with a rotation drive device at the tip of the arm, and a rotation drive device provided at the tip of the robot arm. Needless to say, the present invention can also be applied to a grinding apparatus.

FIG. 1 is a perspective view of a rotary grinding tool according to an embodiment of the present invention.
As shown in FIG. 1, the rotary grinding tool 1 includes a grinding surface 2 composed of a grinding machine surface 3 having a projection 5 formed on the surface of a metal spinning machine and a grinding peripheral surface 4, and a central part of the metal spinning machine. The attachment part provided in is provided. The attachment portion 6 is for attaching the rotary grinding tool 1 to a rotation shaft (not shown) of a grinding tool or a rotary drive device of a grinding apparatus. In the example of FIG. 1, this attachment portion is shown as an attachment hole and engages with the rotation shaft of the rotation drive device. However, the attachment portion 6 is not limited to this example, and the rotation portion of the rotation drive device is rotated. Needless to say, a rotation shaft that engages with the hole of the shaft may be provided, and the shaft of the attachment portion may be engaged with the hole of the rotation shaft of the rotation drive device.

2A and 2B show a state of protrusions formed on a grinding surface 2 ′ of a metal rotating disk in the rotary grinding tool 1 of the present invention, wherein FIG. 2A is a schematic sectional view, and FIG. 2B is a schematic plan view. It is.
As can be seen from FIG. 2 (a), the protrusion 5 protrudes from the surface of the metal rotating disk by the brazing material 9 and the hard particles 7 having a Mohs hardness of more than 9 on the grinding surface 2 ′ of the metal rotating disk 1 ′. It is formed as follows. That is, the hard particles 7 having a Mohs hardness of more than 9 function as an abrasive and are joined to the metal rotating disk 1 ′ by the wax material 9. A part 7a (exposed portion of the hard particle) of the hard particle 7 is exposed from the surface of the wax material, and the remaining portion 7b (an embedded portion of the hard particle) is embedded inside the wax material and joined. . As will be described later, the phantom sphere 8 is for defining the ratio (exposed surface area ratio) of the exposed surface area portion of the hard particles. That is, the virtual sphere is a virtual sphere so that one or more, preferably three or more of the convex portions of the hard particles 7 are circumscribed.

The shape of the protrusion 7 was obtained by using a microscopic observation of the cutting surface in the axial direction of the rotary grinding tool, nondestructive measurement by a stylus type surface shape measuring machine, electron beam measurement by a three-dimensional SEM, a laser microscope with a three-dimensional measurement function, It can be measured by optical measurement. And based on this, the diameter D and height H of said projection part 5 are measurable.
That is, as shown in FIGS. 2A and 2B, the diameter D of the protrusion is cut at a line segment l including two or more adjacent protrusions passing through the apex of the protrusion 5 to be measured in plan view. And the length of the line segment connecting the bottoms a and b of the recesses of the obtained cross-sectional shape curve. In addition, it is good also as an average value measured with two or more line segments with respect to one protrusion. Further, the height H of the protruding portion is the length in the vertical direction from the lower one of the bottom portions a and b of the concave portion to the apex c of the protruding portion in the cross section cut by the line segment l. In addition, it is good also as an average value measured in the cross section cut | disconnected by the 2 or more line segment.
In the present invention, the average H and the average H / D ratio that define the shape of the protrusions are as follows for each protrusion included in any four ranges of a size of 5 mm × 5 mm (0.25 cm ² ) of the ground surface. It is preferable that D and H are measured by the above-described method, and the average value thereof is defined as average D and average H, and average H / D is calculated using average D and average H.

Further, the exposed surface area ratio of the hard particles of the protrusion is the ratio of the surface area of the circumscribed approximate phantom sphere of the portion corresponding to the exposed portion of the hard particle to the total surface area of the circumscribed approximate phantom sphere of the hard particle, such as a microscope or a magnifier. The diameter of the hard particle exposed portion is determined by observing the protrusion, and the ratio of the hard particle diameter to the diameter is obtained, and the surface area of the circumscribed approximate virtual sphere set for the hard particle can be calculated by numerical integration. The average exposed surface area ratio of the hard particles of the protrusions of the present invention is calculated by the above method for any 20 or more protrusions existing in the range of 10 mm × 10 mm (1 cm ² ) of the ground surface. Then, it is preferable that the average of them is the average exposed surface area ratio.

In the rotating grinding tool of (1) of the present invention, hard particles having a Mohs hardness of 9 or more are brazed and bonded to a part or all of the ground surface of the metal rotating disk so that the surface density is 20 particles / cm ² or more. When the height of the protrusions composed of the hard particles and the wax material is H and the diameter of the protrusions is D, the average H is 300 μm or more and the average H / D ratio is 0.3 or more. It was assumed that an average of 10% or more of the surface area of the phantom sphere circumscribing the bonded hard particles was exposed from the surface of the wax material.

If hard particles having a Mohs hardness of 9 or more on the surface of a part of the metal rotating disk serving as a grinding surface are less than 20 surface areas / cm ² , no matter how hard the particles are joined during the work. Some or all of them fall off, and cannot be used for a long time, so that the work efficiency of a large area is reduced, so that it is 20 pieces / cm ² or more. Preferably, when hard particles having a surface density of 30 particles / cm ² or more and a Mohs hardness of more than 9 are brazed, the efficiency of the large-area processing operation is increased. On the other hand, in order to obtain a surface density of 60 / cm ² or more, the cost increases, and it is difficult or impossible to achieve a surface density of 100 / cm ² or more. Therefore, about 30 pieces / cm ^{2 to} 60 pieces / cm ² is optimal.
In addition, this surface density can be calculated | required by measuring the number of the projection parts which exist in the range of arbitrary 10 mm x 10 mm.

  When the average H of the protrusions 5 is less than 300 μm, clogging occurs due to rust powder during grinding, and the working efficiency decreases. If the average H is 300 μm or more, clogging is difficult to occur, and if it is 400 μm or more, maintenance of the tool for clogging can be made unnecessary.

  If the average H / D ratio of the protrusions 5 is less than 0.3, the rust is poor and the grinding efficiency is lowered. Therefore, the average H / D ratio is set to 0.3 or more. If the shape has an average H / D ratio of 0.5 or more, the removal of thick rust and fixed rust is more efficient. However, when the average H / D ratio exceeds 0.8, the structural strength of the protrusions becomes weak, and the protrusions are easily peeled off by an impact during grinding. For this reason, the H / D ratio is preferably set to 0.3 to 0.8.

If the entire surface area of the hard particles 7 having a bonded Mohs hardness of 9 is covered with the wax material at the protrusion 5, only the effect of polishing the surface of the hard fixing rust with a soft wax material can be obtained. It will interfere with rust removal. Therefore, the degree to which the hard particles 7 are exposed from the surface of the brazing material 9 in the protrusion 5 is defined. That is, 10% or more of the surface area of the phantom sphere 8 circumscribed by the hard particles having a Mohs hardness of 9 is exposed to the outside from the surface of the wax material. The calculation of the exposed surface area ratio using a virtual sphere takes into account that the shape of the hard particulate material is complicated. The higher the degree of exposure, the higher the ability to grind fixed rust, but the corresponding reduction in the bonding interface between the hard particles and the wax material makes it easier for the hard particles to peel off and shortens the life of the rotary grinding tool. . As a result of various tests, it is necessary to expose an average of 10% or more of the surface area (imaginary sphere surface area) of the hard particles exceeding Mohs hardness 9 in order to ensure the grinding ability, and further expose an average of 30% or more. Is desirable. On the other hand, if it exceeds 70% on the average, the bonding strength becomes weak, which causes a reduction in work efficiency. The optimum average exposed surface area ratio is about 30 to 50%.
In the present invention, the average exposed surface area ratio of the hard particles of the protrusions is determined by the above-described method for any 20 or more protrusions existing in the range of 10 mm × 10 mm (1 cm ² ) of the ground surface. Calculate and average the surface area ratio as the average exposed surface area ratio.

  Bonding hard particles with a Mohs hardness of 9 is because the hardness of the sticking rust exceeds the Mohs hardness of 9, and in the case of corundum or alumina with a Mohs hardness of 9, the abrasive is polished by the sticking rust, and the sticking rust is removed. This is because it is difficult to remove.

  Thus, in the present invention, the hard particles forming the protrusions are not particularly limited as long as the Mohs hardness exceeds 9, but from the viewpoint of efficiently removing the sticking rust, the hard particles are As described in (2) of the invention, it is preferable to use diamond or cubic boron nitride having an average particle diameter of 200 μm to 1000 μm. This is because if the average particle size of the hard particles is less than 200 μm, clogging is likely to occur, and the grinding performance will be greatly reduced. This is because of a decrease. In addition, industrial diamonds and soot were also considered to increase in cost as the particle size increased. As a result of various tests, it is more desirable that the average particle size is in the range of 300 μm to 750 μm, and it is also efficient in manufacturing to make a tool using industrial diamond or cubic boron nitride having a particle size distributed between 500 μm and 600 μm. Is. Cubic boron nitride is more susceptible to particle destruction than industrial diamond, and the latter can withstand long-time use and has better workability.

The bonding material for forming the protrusions is particularly limited as long as it has a characteristic that can exhibit sufficient bonding properties to both the hard particles having a Mohs hardness of more than 9 and the metal rotating disk as the base material. Instead, an appropriate bonding material (wax material) can be selected according to the material of the hard particles and the metal rotating disk. For example, JIS Z 3265 standard nickel brazing, JIS Z 3261 standard silver brazing, JIS Z 3262 standard copper brazing brazing, JIS Z 3263 standard aluminum brazing solder and brazing sheet, JIS Various types of phosphor copper solder standardized to Z 3264, gold solders standardized to JIS Z 3266, various types of palladium solders standardized to JIS Z 3267, various types of metal solders for vacuum standardized to JIS Z 3268, and JIS Z A base component system can be selected from various solders specified in 3282.
Of these, nickel-based wax materials (for example, BNi-1, BNi-1A, BNi-2, BNi-5, BNi-7, etc.) are often used in consideration of the melting point. In order to improve the bondability with hard particles such as diamond or cubic boron nitride, it is preferable to use a wax material added with 0.5% by mass or more of at least one of titanium, chromium and zirconium.
Further, when a wax material containing 0.5% by mass or more of titanium, chromium and zirconium is used as the wax material and stainless steel is used as the material of the metal rotating disk, the Mohs hardness of the metal rotating disk is 9 or more. The bonding strength of the hard particles increases. This is because a metallurgical reaction occurs at each joint interface between the hard particles and the metal rotating disk and the wax material, and an intermediate phase is formed. This combination of materials effectively works to realize a shear strength of hard particles having a Mohs hardness of 9 or more, which will be described later, of 20 N / piece or more. In order to firmly bond diamond or cubic boron nitride hard particles using nickel brazing material containing one or more of titanium, chromium and zirconium, it is necessary to increase the bonding strength between the brazing material and the metal substrate. However, a nickel brazing material containing one or more of titanium, chromium and zirconium has a good compatibility with stainless steel and can be alloyed to obtain a robust joint. When austenitic stainless steel such as SUS304 is used for the material of the metal rotating disk, the fastness of joining is also improved, and furthermore, the work of removing thick rust is often performed on steel materials placed in a salt damage environment. This is also advantageous from the viewpoint of ensuring the corrosion resistance of the tool itself.

As described above, the rotary grinding tool of the present invention has a projection including hard particles 7 having a Mohs hardness of more than 9 and a brazing material 9 on the surface of a grinding surface portion 2 ′ serving as a grinding surface of a metal rotating disk 1 ′ serving as a substrate. 5 is provided. Hereinafter, the metal rotating disk will be described.
In addition, as explained above, the rotary grinding tool 1 has a protruding portion formed by a hard particle 7 having a Mohs hardness of more than 9 and a brazing material 9 on a grinding surface 2 ′ to be a grinding surface 2 of a metal rotating disk 1 ′ that is a substrate. 5 is formed. As shown in FIGS. 3 to 5, the metal rotating disk 1 ′ of the rotary grinding tool 1 is a disk having a grinding surface 2 ′ composed of a grinding machine surface 3 ′ and a grinding peripheral surface 4 ′. As a rotary grinding tool, there is provided a mounting portion 6 ′ for mounting on a rotating shaft (not shown) of a driving device for rotating the tool. As described above, in FIGS. 3 to 5, as a base for the grinding tool 1, a metal rotating disk is shown, and reference numerals 1 ′ to 5 ′ corresponding to the reference numerals 1 to 5 of the grinding tool are shown and described. ing. In addition, the grinding machine surface and the grinding peripheral surface constituting the grinding surface are set for the sake of convenience. The grinding peripheral surface is a range of about 10 to 15 mm from the peripheral end of the rotary grinding tool, and the remaining grinding surface. Can be treated as a grinding machine surface.

3 to 5 show the shape of the metal rotating disk 1 ′ in the rotary grinding tool 1 of the embodiment of the present invention, (a) is a plan view, and (b) is an A- of (a). FIG. 6 is a sectional view taken along line A (FIG. 3), line BB (FIG. 4), line CC (FIG. 5).
Of the grinding surface 2 'of the above-mentioned metal rotating disk composed of the grinding machine surface 3' and the grinding peripheral surface 4 ', the angle θ between the normal line X of the grinding machine surface 3' and the rotation center axis Y is 0 °. As can be seen from FIG. 3 (b), FIG. 4 (b), and FIG. 5 (b), as shown in (3) of the present invention, it has a portion that is 1 ° to 45 °. It is preferable to do so. This is to improve work efficiency and safety as a shape that is easy for the operator to handle. That is, for example, in order to enable an operator to easily remove thick rust generated in a large-area steel structure while considering the overall shape of a commercially available disc grinder driving device, the grinding machine surface portion 3 ′ If the angle θ between the normal line X and the rotation center axis Y is only 0 °, the operator cannot incline and hold the electric tool with respect to the surface to be ground, and the work efficiency is lowered. It also increases the risk. On the other hand, if only θ exceeds 45 °, it becomes difficult to handle the disc grinder, and work efficiency and safety are lowered.
Further, the vicinity of the boundary between the grinding machine surface 3 ′ and the grinding peripheral surface 4 ′ of the metal rotating disk may be an acute cross-sectional shape, but preferably a sectional curvature of R1 mm or more and R10 mm or less is provided in the vicinity of the boundary between the two. It shall have a part. This is because if the cross-sectional curvature near the boundary between the cutting peripheral surface 4 ′ and the grinding machine surface 3 ′ is less than R1 mm, the thick rust is likely to be cut too much, and the surface destruction efficiency is lowered. It is because the efficiency of the cutting work to the thick rust using the circumference part of a grinding tool will fall that it exceeds R10mm. As an effective range, R3 to R7 mm is desirable.

As shown in FIG. 3, the planar shape of the metal rotating disk used as the rotary grinding tool may be a uniform circle, but as shown in FIGS. 4 and 5, a notch 10 is formed in the circumferential part of the metal rotating disk. It is also preferable to add. In FIG. 4, the notch 10 shows a band-like notch from the circumferential part toward the center, and FIG. 5 shows a circular notch in the circumferential part. These cuts are preferably provided so as to be symmetrical with respect to the central axis.
As described in (4) of the present invention, the reason why the slits are provided symmetrically from the circumference of the metal rotating disk is to increase the impact force on the thick layered rust. This reduces or eliminates the need to roughly remove the thick rust with a hammer. Although the number of cuts may be an odd number, it is preferable to arrange an even number of rotary grinding tools of the present invention that rotate at high speed on the center object so that the balance is not lost during operation. Although the shape of the notch 10 can be set arbitrarily, it is preferable to provide an even number of the same shape in consideration of the mass balance of the rotating metal disk.

The weight of the rotary grinding tool of the present invention is not particularly limited. However, when the rotary grinding tool is attached to a small rotary drive device such as a disc grinder and the operator performs the grinding operation by hand, (5 ), The weight of the metal rotating disk is preferably 160 g or more.
By setting the mass of the metal rotating disk to 160 g or more, the impact force on the thick rust can be increased. The rotational speed of the rotary grinding tool is determined by the specifications of the power unit of the disc grinder driving device. However, since the impact force depends on the mass of the rotary grinding tool, a larger mass is more effective. However, if the mass of the metal rotating disk exceeds 900 g, the rotational moment increases, and it becomes difficult for the operator to change the direction of the rotary grinding tool. The most manageable mass is in the range of 250 to 750 g. However, when working by attaching to a mechanical holding device such as a robot, there is no need to set an upper limit.

In the rotary grinding tool of the present invention, the diameter of the tool is not particularly limited, and from a large diameter to a small diameter depending on the necessity of the location to be ground and the size of the rotary drive device to which the tool of the present invention is attached. Although the size of the metal turntable can be selected as appropriate, as described in (6) of the present invention, the diameter of the metal turntable is preferably 50 mm or more.
That is, this is because the work can be performed by being mounted on an electric rotating device such as a commercially available disc grinder driving device or a hand drill driving device. When the diameter is less than 50 mm, it is difficult to attach to a commercially available electric rotating device, and at the same time, it is difficult to efficiently remove thick rust spreading over a large area. As a result, it can be mounted on a commercially available electric rotating device, so that it is possible to carry out painting ground processing work on-site, and there is no need to use a large blasting device or the like. In addition, when attaching to a commercially available disk grinder drive device, the diameter of the most common and easy-to-use metal rotating disk is 90 to 115 mm, and 100 mm is standard. Further, depending on the specifications of a commercially available disc grinder driving device, a metal rotating disk having a diameter of 180 mm or more can also be applied. When mounting on a mechanically held rotary drive device such as a robot, a larger metal turntable can be used for further efficiency.

As described in (7) of the present invention, the average shear strength of the hard particles having a Mohs hardness of more than 9 forming the protrusions of the rotary grinding tool of the present invention is preferably 20 N / piece or more.
For example, when diamond with Mohs hardness of 10 collides with the work steel surface at high speed, the diamond often breaks due to thermal fatigue, but this measure is not sufficient in the past, and hard particles (abrasive grains) have been taken up and detached. Therefore, when working on the steel surface, the service life was short. However, if the average shear strength of the hard particles is 20 N / piece, the hard particles (diamond) roots remain in the projections at the joints even if the hard particles are damaged by thermal fatigue, and the grinding operation can be continued. That is, this shear strength evaluates the joint strength between the hard particles and the wax material at the protrusions. The shear strength is measured by holding a metal turntable brazed with hard particles on the stage, holding an exposed portion of the hard particles using a carbide pawl tool connected to the load cell, Is applied to obtain a load when the hard particles are detached. For example, the shear strength can be measured by using a bonding tester manufactured by Reska as a measuring device.
In the present invention, the average shear strength is determined by measuring the shear strength of the hard particles of each projection by the above-described method for any 20 or more projections in the range of 10 mm × 10 mm (1 cm ² ). It is preferable to use the average value as the average shear strength.

  Thus, in order to realize a high average shear strength of 2N / piece or more on average, as described above, an alloy containing 0.5% by mass or more of one or more of titanium, chromium, or zirconium is used as a brazing material. Is preferred. For example, 70 mass% Ag-28 mass% Cu-2 mass% Ti alloy, 74 mass% Ni-14 mass% Cr-3 mass% B-4 mass% Si-4.3 mass% Fe-0.7 mass% C alloy, 83 mass% Ni-7 mass% Cr-3 mass% B-4 mass% Si-3 mass% Fe alloy, 71 mass% Ni-19 mass% Cr-10 mass% Si alloy, 77 mass% Ni- It is preferable to use a wax material such as a 10 mass% P-13 mass% Cr alloy.

The manufacturing method of the rotary grinding tool of the present invention is not particularly limited, and it is needless to say that an appropriate method can be selected, but the manufacturing method described in (8) of the present invention is also preferable. That is, wax powder mixed with an organic binder is applied to the grinding surface of a metal rotating disk so that the average particle diameter of hard particles exceeding Mohs hardness 9 is 20 to 60%, and Mohs hardness 9 is exceeded. The hard particles are applied so as to have a predetermined surface density, and are held at a temperature of 1000 ° C. or higher and 1040 ° C. or lower for 10 minutes or more and 50 minutes or less under a reduced pressure of 10 ⁻⁴ Torr or less. Thereby, the rotary grinding tool for rust removal and substrate adjustment described in (1) to (7) of the present invention can be manufactured. Diameter D, height H, H / D of protrusions composed of hard particles with a Mohs hardness of more than 9 and a wax material, exposed surface area ratio of the hard particles from the wax material surface, and bonding strength between the wax material and the hard particles (Shear strength) etc. can be optimized by adjusting the balance of bonding interfacial tension by adjusting the type of wax material, the type of thickness of the wax material, the heating conditions, etc. . For example, the wettability does not increase at a temperature or time below a specified level, resulting in a decrease in shear strength. In addition, when the holding temperature and time are out of the above range, the wettability becomes too good, and the hard particles are completely covered with the wax material, so that the grinding ability is greatly reduced. Further, when the decompression condition exceeds the above atmospheric pressure, the oxidation proceeds, so that the shear strength decreases.

A more preferable production condition is that wax powder is applied so as to have a thickness of 25% to 35% of the average particle diameter, and is maintained at 1010 ° C. to 1030 ° C. for 25 minutes to 35 minutes at 10 ⁻⁵ Torr or less. . In addition, the manufacturing method of the metal turntable of the rotary grinding tool of the present invention is not particularly limited. For example, a method of forming from a thin steel plate by a method of cutting from a stainless steel plate or press forming, etc. Is applicable.

  The rotary grinding tool for rust removal and substrate preparation according to the present invention is not only useful for repair coating of corroded steel structures, but also can efficiently remove thick sticking rust generated in steelmaking intermediate products. As a result, production elasticity in the steelmaking process is improved. Needless to say, it can also be used for substrate preparation involving grinding of a material having a Mohs hardness of 10 or less, including inorganic materials such as concrete, rocks and minerals, metals, organic materials or composites thereof. That is, as described in (9) of the present invention, the material having a Mohs hardness of less than 10 is ground using the rotary grinding tool for rust removal and substrate adjustment described in any of (1) to (7). As a result, rust removal and grinding can be efficiently and stably performed on the above-described object.

Hereinafter, based on an Example, this invention is demonstrated further more concretely.
Example 1
About the rotary grinding tool as shown in FIG. 1, the grinding performance of the rotary grinding tool was investigated by changing the type of hard particles forming the protrusions, the average particle size, the surface density, H / D, and the exposure rate of the hard particles. .
As a rotating grinding tool, a metal rotating disk (mass 290 g) of SUS304 having a diameter of 100 mm and having no cut as shown in FIG. 3 was used. A paste obtained by adding polyvinyl alcohol as an organic binder to a wax material powder of BNi-1, BNi-1A, BNi-2, or BNi-7 is applied to the surface of a metal rotating disk serving as a grinding surface. The hard particles having the average particle size shown in Table 1 were applied so as to have a predetermined areal density, and kept at 1020 ° C. for 30 hours under a reduced pressure of 10 ⁻⁵ torr. A protrusion was formed by joining to a rotary grinding tool.
The shape of the protrusion was measured using a stylus type three-dimensional shape measuring instrument (surface roughness meter) (Tokyo Seimitsu Surfcom 575A-3D) to obtain H and D. Also, the exposed surface area ratio of the hard particles is determined by observing the protrusions with a microscope or a magnifying glass, obtaining the ratio of the hard particle exposed portion diameter to the hard particle diameter, and calculating the ratio of the hard particle diameter to the circumscribed approximate virtual sphere. The surface area was calculated by numerical integration. The H / D values shown in Table 1 are obtained by calculating the H value and the D value for the protrusions in the three surfaces of 0.25 cm ² arbitrarily selected from the representative portions, and averaging them to calculate the H / D value. The value was determined. The surface density was determined by counting the number of protrusions in a 1 cm ² surface arbitrarily selected from representative portions. The exposed surface area ratio and the shear strength of the hard particles were obtained by averaging the values obtained by arbitrarily selecting 20 representative protrusions on an arbitrary 1 cm ² ground surface and performing the above-described measurement and evaluation. Table 1 shows the properties of the protrusions of the rotary grinding tool. Table 1 shows the properties of the protrusions of the rotary grinding tool.
Next, the grinding performance of this rotary grinding tool was evaluated. The evaluation method of the grinding performance of this rotary grinding tool is based on the above-mentioned rotary grinding for a test piece of weathering steel (JIS G3114 SMA490) in which layered rust having a thickness of about 2 mm is formed by spraying salt water for half a year. The tool was attached to a disk grinder driving device, and the rust of the test material was removed by the operator, and the work time for obtaining a base surface equivalent to 1 m ² of ISO-Sa2 was used. The results are shown in Table 1.

From the results shown in Table 1, the working time for obtaining a base surface equivalent to Sa2 defined in 1 m ² of ISO1805-1 is hard particles bonded to the grinding surface, particle diameter and surface density, H value, H / It turns out that it changes depending on D ratio, the exposure rate of a hard particle, etc. According to the rotary grinding tool of the present invention (present inventions 1 to 8), the above-mentioned ground surface can be obtained within 60 minutes. On the other hand, in comparisons 1 to 4, the work time was long. Very good results were obtained when industrial diamonds with an average particle size of 500 to 600 μm were deposited with a paste consisting of BNi-2 wax powder and an organic binder based on polyvinyl alcohol, and vacuum waxing. (Inventions 4 and 5). Although not shown in Table 1, we tried joining industrial diamonds by various joining methods such as thermosetting resin, nickel plating, etc., but none of them could achieve an average shear strength of 20 N / piece or more, Further, in the actual rust removal test, industrial diamond was released soon after use, the grinding function was lowered, and the efficiency could not be secured. If a brazing material in which an intermetallic compound or alloy is formed at the interface with both industrial diamond and a metal turntable is used, even if the diamond is chipped off, the root joint is maintained and remains, so that It was able to withstand harsh work. Cubic boron nitride (CBN) was also brazed and joined in the same manner as described above (Invention 8), but the grinding efficiency was slightly reduced compared to that using an industrial diamond having the same particle diameter (Invention 1). ing. In the rotary grinding tool (Comparative 4) in which corundum particles having a Mohs hardness of 9 were brazed and joined, the abrasive particles were scraped to the fixed rust, requiring a long time for the work and a short tool life.

Example 2
In the rotary grinding tool, the influence on the grinding performance (difference in working time) by the mass of the metal rotating disk and the presence or absence of the slit of the metal rotating disk was investigated. The metal rotating disk is made of SUS304 having a diameter of 100 mm, and the projecting portion is made of industrial diamond having an average particle diameter of 500 μm as hard particles, and 82.5 mass% Ni-7 mass% Cr-3 mass% B-4 as a wax material. .5 mass% Si-3 mass% Fe alloy (BNi-2) powder and a paste composed of an organic binder mainly composed of polyvinyl alcohol, and attached to a metal turntable under a reduced pressure of 10 ⁻⁵ torr, It was held at 1020 ° C. for 30 minutes, and was joined by brazing under reduced pressure. This was attached to the drive device of the disk grinder, and the test material was ground by the operator. The properties of the grinding surfaces of the obtained rotary grinding tools were all the same as those of the invention 4 in Example 1 shown in Table 1. That is, the properties of the grinding surfaces of the comparative grinding tools 5 and 6 and the rotary grinding tools of the present invention 9 to 17 were as follows: average particle size: 500 μm, surface density: 100 particles / cm ² , average H: 1100 μm, average H / D: 0.00. 6. The average exposed surface area ratio of hard particles is 50 (%), the average shear strength is 36 (N / piece), and only the mass of the metal rotating disk and the presence or absence of slits of the metal rotating disk are different. The test material and the evaluation method for evaluating the grinding performance were the same as in the case of Example 1. Further, regarding the operability when the operator grinds with the rotary grinding tool attached to the grinder driving device. Was also evaluated. Evaluation is x unstable. Δ: Can be used. ○: Good, ◎: Very good. The results are shown in Table 2.

As can be seen from Table 2, if the metal turntable is too light, the working efficiency is low. This is thought to be because it is difficult to stabilize the state of contact between the tool rotating at high speed and the steel surface to which rust adheres, vibration occurs, and the impact force on the thick fixing rust is also weakened. Further, it is not desirable from the viewpoint of safety. If it is 160 g or more, it can be used efficiently and stably. If the mass is too large, the electric tool that rotates at 12000 revolutions / minute increases the rotational moment of the metal disk, which requires extra operator force in the operation of changing the direction of the tool. The tendency appears from the mass of 800 g, and the worker feels danger at 1000 g or more. However, the upper limit can be relaxed if it is considered to be performed by a machine such as a robot.
Moreover, if a slit is provided in the circumferential part of the metal rotating disk, the working efficiency is improved. Although it seems that the effect is small when viewed in 1 m ² , this difference is not small because it will work on a huge area when it becomes a real structure. Overall, it can be seen that the rotary grinding tool of the thirteenth invention is the best in this embodiment.

Example 3
Moreover, the use performance was evaluated qualitatively about the typical thing of the rotary grinding tool of this invention. That is, the qualitative evaluation of the operator with respect to various grinding tools capable of removing a thick rust as a coating base treatment is shown in Table 4 according to the present invention 4, the present invention 8 and the present invention 13 shown in Table 2 (grinding surface). The properties of are the same as those of the present invention 4, and the number of the slits and the weight of the metal disk are different from those of the present invention 4) and the conventional grinding tools (Comparison 7 to 17). The test material for evaluating the grinding performance was the same as in the case of Example 1, but the evaluation was based on the destruction of thick rust, the removal of sticking rust, the safety of work, the work efficiency, the degree of noise generation, This was performed with respect to the degree of dust generation, and these were comprehensively evaluated. The degree of evaluation was as follows: ◎ very good, ◯ good, △ improvement required, and x many problems. The results are shown in Table 3.

  As can be seen from Table 3, other grinding tools other than the present invention cannot satisfactorily remove thick rust by a single method using only one type of tool or abrasive material. The grinding tools of No. 13 and No. 13 gave a good overall evaluation.

Example 4
Moreover, working efficiency was confirmed about the typical thing of the rotary grinding tool of this invention. That is, the present invention 4 shown in Table 1 and the present invention 13 shown in Table 2 when the conventional grinding tool is combined with the working speed for obtaining a metal base equivalent to ISO-Sa2 (Comparison 18-23). Comparison was made with a grinding tool having the same grinding surface properties as in the present invention 4 and different in the number and weight of the slits of the metal disk from the present invention 4. The test material processed for evaluation is the same as in Example 1. The results are shown in Table 4.

  As can be seen from Table 4, when the grinding tool of the present invention is used, the rough removal of the thick rust before blasting and the adjustment grinding process can be omitted completely, so that the work efficiency is greatly improved comprehensively. This greatly reduces the load on the workers. Furthermore, since no large-scale equipment can be required, the cost can be drastically reduced considering the transportation cost of such equipment to the site.

  In view of manufacturing a metal disk by cutting, the present invention 4 shown in Table 1, which can be press-shaped and can minimize the manufacturing cost, or a similar shape is practically good. In addition, the rotating grinding tool of the present invention having a metal rotating disk diameter of 180 mm, 70 mm, and 55 mm was also able to confirm an efficient and effective thick rust removing function. It is good to use properly according to the shape of the steel structure.

  Removing rust stuck to weathering steel has been one of the most difficult to achieve with conventional grinding tools. However, with the rotary grinding tool for rust removal and substrate adjustment according to the present invention, It is also possible to grind inorganic materials such as concrete, rocks, minerals, metals, organic materials or their composites having a hardness of less than 10. For example, the concrete piece was ground using the grinding tool of the present invention 4 shown in Table 1, and high-speed grinding and substrate adjustment at a depth direction of 30 mm / min were achieved. Various rocks are included as aggregates in the concrete, and this proves that the grinding tool of the present invention can also grind rocks.

In the coating film removal test of steel coated with an organic material having a thickness of 600 microns using the grinding tool of the present invention, the organic coating film is ground and removed at a high speed of 10 minutes / m ² , and the base material of the steel can be adjusted. It was. In addition, it was possible to grind vinyl chloride, fluororesin, acrylic tree species, polystyrene resin, and various types of wood as organic materials without problems. In addition, even in the case of aluminum, magnesium, zinc and alloys thereof used for sacrificial anodes for cathodic protection, grinding and substrate adjustment with the grinding tool of the present invention can be performed without any problem. As examples of minerals, iron ore, fluorite, corundum, ruby, pyrite, feldspar, quartz, calcite, and coal could be ground without problems. As an example of an artificial inorganic material, glass grinding and substrate preparation could be performed without any problems. Thus, by using the rotary grinding tool of the present invention, not only steel materials but also concrete, organic materials, wood, etc., as well as various alloys and minerals can be adjusted with grinding. It is.

It is a perspective view which shows one Embodiment of the rotary grinding tool of this invention. It is drawing which shows typically the shape of the projection part formed in the surface of the rotary grinding tool of this invention, (a) is sectional drawing, (b) is a top view. It is a figure which shows the shape of the metal rotating disk of one Embodiment used for the rotary grinding tool of this invention, (a) is a top view, (b) is AA sectional drawing of (a). It is a figure which shows the shape of the metal rotary disk of other embodiment used for the rotary grinding tool of this invention, (a) is a top view, (b) is BB sectional drawing of (a). It is a figure which shows the shape of other embodiment of the metal rotating disk used for the rotary grinding tool of this invention, (a) is a top view, (b) is CC sectional view taken on the line (a). It is an external view of the surface of the exposure test body of nickel-type high weather resistance steel. It is a figure which shows that the sticking rust formed in the exposure test body surface of nickel-type high weather resistance steel is removed by this invention.

Explanation of symbols

1 Rotating grinding tool 1 'Metal rotating disc (base material for rotating grinding tool)
2,2 'Grinding surface 3,3' Grinding machine surface 4,4 'Grinding peripheral surface 5 Protrusion 6,6' Mounting portion 7 Hard particle 7a Hard particle (exposed portion)
7b Hard particles (buried part)
8 Approximate virtual sphere circumscribed by hard particle 9 Brazing material 10 Notch a, b Bottom of recess c Top of protrusion l Line segment passing through top of protrusion

Claims (9)

A rotary grinding tool comprising a metal rotary disk having a central mounting part for mounting on a rotary shaft of a rotary drive device and a grinding surface composed of a grinding machine surface and a grinding peripheral surface, the grinding surface of the metal rotary disk A hard particle having a Mohs hardness of more than 9 is brazed and bonded to a part or all of the surface to have a surface density of 20 particles / cm ² or more. The height of the protrusion formed by the hard particle and the wax material is H, When the diameter is D, the average H is 300 μm or more, the average H / D ratio is 0.3 or more, and the hard material exposed from the surface of the wax material using the phantom sphere circumscribing the hard particles of the protrusion A rotary grinding tool excellent in rust removal and substrate adjustment, characterized in that when the exposed surface area ratio of particles is determined, the average exposed surface area ratio is 10% or more.   The hard particles having a Mohs hardness of 9 or more are diamond or cubic boron nitride having an average particle size of 200 μm or more and 1000 μm or less, and the wax material contains one or more of titanium, chromium and zirconium in an amount of 0.5% by mass or more, 2. The rotary grinding tool excellent in rust removal and substrate adjustment according to claim 1, wherein the material of the metal rotating disk is stainless steel.   On the grinding surface of the metal rotating disk composed of a grinding machine surface and a grinding peripheral surface, the grinding machine surface has a portion where the angle between the normal line of the grinding machine surface and the rotation center axis is 1 ° or more and 45 ° or less, The grinding peripheral surface has a portion in which a curvature radius R of a cross section parallel to the rotation center is 1 mm or more and R10 mm or less, and is excellent in rust removal and substrate adjustment according to any one of claims 1 to 2. Rotating grinding tool.   It is excellent in rust removal and substrate adjustment according to any one of claims 1 to 3, wherein an even number of cuts are provided in the center axis object from the circumferential part to the center part of the metal rotating disk. Rotating grinding tool.   The rotary grinding tool excellent in rust removal and substrate adjustment according to any one of claims 1 to 4, wherein the metal turntable has a mass of 160 g or more.   The diameter of the said metal rotary disk is 50 mm or more, The rotary grinding tool excellent in the rust removal and base adjustment of any one of Claims 1-5 characterized by the above-mentioned.   7. The rotary grinding tool excellent in rust removal and substrate adjustment according to claim 1, wherein an average shear strength of hard particles having a Mohs hardness of 9 or more is 20 N / piece or more. Apply a wax powder mixed with an organic binder to the ground surface of the metal rotating disk so that the average particle diameter of hard particles exceeding Mohs hardness 9 is 20 to 60%. More than 20 hard particles / cm ^{2 and} a surface density of more than 20 particles / cm ² are applied and held at a temperature of 1000 ° C. to 1040 ° C. for 10 minutes to 50 minutes under a reduced pressure of 10 ⁻⁴ Torr or less. A method of manufacturing a rotary grinding tool excellent in rust removal and substrate adjustment.   A substrate adjustment method comprising grinding a substance having a Mohs hardness of less than 10 using the rotary grinding tool excellent in rust removal and substrate adjustment according to any one of claims 1 to 7.