JP3474812B2 - How to insert a large-diameter disc-shaped cutting tool - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a large-diameter disk for brazing a cutting edge such as a diamond segment to the outer peripheral edge of a steel disk for use in high-speed cutting of an object to be cut such as stone or concrete. The present invention relates to a method of inserting a flat cutting tool.

[0002]

2. Description of the Related Art Conventionally, among disk-shaped cutting tools used for cutting stones, concrete, etc., large diameter ones have a diameter of about 800-2500 mm, while their thickness is as thin as about 5-10 mm. Therefore, if you do not give enough support, you will not be able to obtain an accurate vertical surface by bending the cutting tool when it is set in the cutting machine, and rotate the cutting tool to make stones, concrete, etc. When a hard work piece is cut, the outer peripheral edge of the disk of the cutting tool expands due to frictional heat, and a compressive stress is applied to the outer peripheral edge of the disk by the target object, so that a buckling phenomenon occurs and cutting becomes impossible. There was an occasion.

Therefore, in such a cutting tool, a technician generally hammers a predetermined annular portion excluding the outer peripheral edge portion of the disk with a hammer to plastically extend the annular portion, and the annular portion is inserted. By applying a compressive stress to the disk, tensile stress is generated in the circumferential direction of the disk, and it is possible to resist the compressive force applied to the disk edge due to thermal expansion during cutting to prevent buckling. .

Further, as a disc-shaped cutting tool 1 for cutting an object to be cut such as stone or concrete, as shown in FIG. 6, a high carbon steel plate 2 represented by SK or SKS is cut into a circle. To form the disk 3, and engraving the notch recess 4 in the peripheral edge of the disk 3, and quenching the disk 3,
A step of tempering is performed, and then a predetermined annular portion 5 excluding the peripheral edge of the disk 3 is elastically stretched with a hammer, and then the notched concave portion 4 is engraved to form a convex portion. There was one formed as the cutting tool 1 by brazing the diamond segment 7 to 6.

Among the high carbon steel sheets such as SK and SKS, general structural steels manufactured in accordance with JIS standard are hard and lack in toughness, so they are brittle and cannot be fitted into the steel. In the case of a carbon steel sheet, the tempering temperature after quenching is set higher than the JIS standard, and the tempering hardness is reduced to about HRC35 to 40 to improve the toughness and allow proper tempering.

[0006]

However, since the high carbon steel plate 2 such as SK or SKS has a high carbon content, the weldability when brazing the diamond segment 7 to the convex portion 6 of the disk 3 is poor, Moreover, if it is a welding method such as laser welding that locally adds high energy,
There was a risk that quench cracks would occur in the vicinity of the welded portion of the disk 3.

Further, as shown in FIG. 7, the high carbon steel plate 2 such as SK and SKS used as a cutting tool has a hardness of HRC3 by setting a high tempering temperature to be set.
Since it is lowered to about 5 to 40, it is easily worn. Especially, the convex portion 6 to which the diamond segment 7 is brazed is greatly worn at the time of cutting due to its shape and the frequency of contact with the object to be cut. Is shortened. In addition, the larger the diameter of the disk 3, the more expensive it is, which poses a problem of a large economic burden.

A hammer is used to insert the waist into the large-diameter disc-shaped cutting tool 1 as described above. It was inefficient because it required a lot of time and labor.

In the case of medium carbon steel sheet such as SCM,
Since the toughness is higher than that of the high-carbon steel plate, the possibility of quench cracking due to welding is low, but the yield ratio is low and the spring property is poor. Therefore, it was not suitable for a large-diameter disc-shaped cutting tool.

On the other hand, low carbon steel sheets are generally not as suitable for cutting tools because they are softer and have a lower yield ratio than the medium carbon steel sheets, but among the low carbon steel sheets, the soil plate of a bulltozer and the bed of a dump truck, etc. Low carbon wear resistant steel plate used in civil engineering equipment has high toughness and wear resistance, has hardness of HRC50 equivalent to steel for impact resistant tool, and has excellent weldability. . However, even in the case of this low-carbon wear-resistant steel plate, it cannot be used as a cutting tool because it has a high hardness and cannot be inserted even if it is hammered with a hammer.

[0011]

In the present invention, in view of the problems of the conventional large-diameter disc-shaped cutting tool described above, a low-carbon wear-resistant steel plate having high toughness and excellent abrasion resistance is formed into a large-diameter disc. The purpose of the present invention is to provide a method for inserting the formed cutting tool economically and efficiently.

[0012] The invention of claim 1 as means for that,
After forming a low-carbon wear-resistant steel plate into a large-diameter disk shape and heating and tempering a predetermined annular portion excluding the outer peripheral edge of the disk, the tempered portion is expanded. By doing so, the second waist insertion is performed, and tensile stress is applied in the circumferential direction of the peripheral edge portion of the disk.

According to a second aspect of the present invention, in the first aspect of the first aspect of the present invention, the first waist insert of the disc is 150 ° C. at a predetermined annular portion excluding the outer peripheral edge of the disc by heating means such as flame or high frequency induction. By heat-treating in the range of up to 400 ° C and tempering, the retained austenite is decomposed into bainite to expand the volume, and the tempering reduces the hardness of the annular portion to facilitate the elongation process. The second waist insert is characterized in that the annular portion is expanded by a hammer or a pressure roller.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment of a method for inserting a large-diameter disc-shaped cutting tool according to the present invention will now be described with reference to the drawings. FIGS. 1 and 2 show the large-diameter disc-shaped cutting tool according to the present invention. It is explanatory drawing of the cutting tool manufactured by the waist insertion method of FIG.

The low carbon wear resistant steel plate 12 used in the large-diameter disc-shaped cutting tool 11 is a steel plate having a carbon content of 0.23 to 0.28% and a hardness of HRC50, and has high toughness and wear resistance. It is a steel plate that also has wear resistance and is used as a wear resistant steel plate for civil engineering machinery. As such a steel plate, for example, W
EL-TEN AR500S (Nippon Steel Corporation) is available, and this steel sheet has carbon 0.23 to 0.28% and silicon 0.15 to 0.35.
%, Manganese 0.3 to 0.8%, phosphorus 0.01% or less, sulfur 0.01
% Or less, chromium 0.3 to 0.7%, molybdenum 0.15 to 0.5%
Rolled steel plate containing 880 ° C to 9 while pressing
After being quenched at 00 ° C, it is tempered at 200 ° C or less.

The disk 13 of this embodiment has a thickness of 8.5.
mm flat plate low carbon wear resistant steel plate 12 with a diameter of 1500 m
In addition to cutting into a large-diameter disk shape of m, a plurality of notched recesses 14 are engraved on the peripheral edge of the disk 13 at predetermined intervals, and the entire peripheral edge is formed in an uneven shape.

Next, the method of inserting the disk 13 into the waist will be described. As the first waist inserting, as shown in FIG.
The annular portion 15 between about 30 cm and 45 cm from the center of the disk 13 is uniformly applied from both sides of the disk 13 by using an appropriate heating means 18 such as flame or high frequency induction at 150 ° C to 4 ° C.
It is performed by heating in the range of 00 ° C.

By this heating, the retained austenite in the steel component is decomposed into bainite in the annular portion 15 and the volume thereof is expanded by about 4 to 5%, and the expansion causes a compressive stress to be applied to the annular portion 15. , Ring part 1 of disk 13
A circumferential tensile stress is generated on the outer side 19 of No. 5.

The residual austenite is 150 ° C.
It decomposes to bainite in the range of 400 ° C, particularly 220 ° C to 300 ° C, and when this decomposition is completed, the annular portion 15 does not expand even if heated over a longer period of time. There is a limit to the compressive stress applied to No. 15, and heating alone does not lead to proper waisting.

Next, after the heated annular portion 15 is air-cooled, the disk 1 is used as a second waist insert as shown in FIG.
3 Circumference 2 passing through the center of the annular portion 15 on both sides in the width direction
0, the rollers 23 having the protrusions 22 on the pressure surface 21 are symmetrically arranged, and the rollers 23 are rotated along the circumference 20 so that the protrusions 22 on the pressure surface 21 continuously form the concave groove 24 in the disk 13. The disk 13 is plastically expanded by forming the, and compressive stress is further applied to the annular portion 15. At this time, since the annular portion 15 is expanded by heating and has a low hardness, the roller 23 can be easily stretched.

Incidentally, in the second waist insertion, an appropriate pressing means such as hammering may be used instead of the roller 23.

The large-diameter disk 13 thus placed in the waist
Is the diamond segment 1 on the top surface of a plurality of projections 16 formed by engraving the cutout recesses 14 on the outer peripheral edge.
The large-diameter disc-shaped cutting tool 11 is formed by brazing 7.

On the other hand, FIG. 5 shows a large-diameter disc-shaped cutting tool 1 according to the present invention.
This is another embodiment of the waist insertion method of No. 1, but in this case, a low carbon wear resistant steel plate 12 similar to the above embodiment is formed into a disc shape, and a portion of about 25 cm from the center of the disc 13 and 50 cm. , And two annular portions 15a and 15b each having a width of about 2 cm are set in these portions.
280 are heated by a heating means 18 such as high frequency induction.
After heating to ° C and applying a predetermined amount of compressive stress to perform the first waist insertion and then air cooling, the annular portion 15
In the same manner as described above, a and 15b are pressed by the roller 23 having the projections 22 on the compression surface 21 to plastically expand and apply compressive stress to perform the second waist insertion, and the annular portion 15a of the disk 13 is , 15b to generate a tensile stress on the outer side.

Large-diameter disc-shaped cutting tool 11 formed in this way
Is the amount of deformation measured by a deformation amount measuring device, and the residual stress value is 1
If the appropriate value corresponding to kg / mm ² is met, it means that proper waist support has been performed.

If the residual stress value does not reach the proper value in the above measurement, the number of places to be inserted is increased, and double,
It is possible to set a proper value by triple insertion into the waist, and the place and width to be inserted can be appropriately set depending on the thickness and diameter of the disk 13.

A low carbon abrasion resistant steel plate 12 similar to this cutting tool was formed into a disk shape, and was plastically expanded by hammering with a hammer or only by pressing the rollers without heating the waist. It was created and the amount of deformation of this disk was measured by a deformation amount measuring device, but it was found that the residual stress value did not reach the appropriate value, and that proper expansion could not be achieved by plastic expansion alone.

Therefore, the low carbon abrasion-resistant steel plate 12 heats the annular portion 15 to be inserted into the elastic portion, and the plasticity of the annular portion 15 is modified by heating so that the roller 23 expands the plasticity. It was found that it is easy to do this, and it is only after the synergistic action of heating and spreading that proper waist insertion becomes possible.

Further, the above-mentioned disc-shaped large-diameter cutting tool 11 was rotated at a peripheral speed of 40 m / sec to cut the granite, but thermal expansion buckling was not observed and proper hip insertion was performed. Was recognized.

Further, the cutting tool 11 is provided with a low carbon wear resistant steel plate 12
It was found that the disk wear was extremely less than that of high carbon steel plates such as SK and SKS, and there was no particular problem even at high speed rotation of 40 m / sec or more.

[0030]

As described above, according to the method of inserting a large-diameter disk-shaped cutting tool according to the present invention, a low-carbon wear-resistant steel plate having high toughness is circled by the first insertion by heating. Since the annular portion is expanded and a compressive stress is applied to the annular portion, the annular portion is expanded and further compressed to add a compressive stress. It is possible to manufacture a large-diameter disc-shaped cutting tool with a low-carbon wear-resistant steel plate that has several times the wear strength compared to the cutting tools used with high-carbon steel plates such as SK and SKS. This has the effect of dramatically increasing the life of the main unit and reducing the economic burden.

Further, since this low-carbon wear-resistant steel plate has high toughness, it has good weldability when brazing diamond segments and can prevent quenching cracks of the steel plate at the welded portion. It has the advantage of facilitating the manufacture of the device.

Furthermore, since heating can be performed properly by high-frequency induction and composition spreading by a roller, proper operation can be performed, and automation can be performed, and manufacturing efficiency can be improved.

Moreover, by using a low-carbon wear-resistant steel plate for the disk body of the large-diameter disk-shaped cutting tool, it is possible to perform high-speed rotation cutting and shorten the cutting work time.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a preferred embodiment of a large-diameter discoid cutting tool according to the present invention.

2 is an enlarged cross-sectional view taken along the line AA shown in FIG.

FIG. 3 is an explanatory view showing a waist insertion method by heating.

FIG. 4 is an explanatory view showing a waist insertion method by stretching.

FIG. 5 is an explanatory view showing another embodiment of the large diameter disc-shaped cutting tool according to the present invention.

FIG. 6 is an explanatory diagram showing a conventional technique of the present invention.

7 is an enlarged sectional view taken along line BB shown in FIG.

[Explanation of symbols]

11 large diameter disc-shaped cutting tool, 12 steel plates, 13 discs, 14 notch recess, 15 ring part, 16 convex part, 17 diamond segments, 18 heating means, 19 outside, 20 circles, 21 pressure surface, 22 protrusions, 23 rollers, 24 groove,

Claims (2)

(57) [Claims] 1. A low carbon wear resistant steel plate is formed into a large-diameter disc shape,
After heating the first annular part of the disk excluding the outer peripheral edge of the disk by heating and tempering the first annular part, the second part of the annular part is stretched to form a second waist part. A method for inserting a large-diameter disc-shaped cutting tool, characterized in that tensile stress is applied in the circumferential direction of the portion. 2. The first waist insert of the disk is 150 ° C. to 4 ° C. by a heating means such as flame or high frequency induction on the annular part.
By heat-treating and tempering in the range of 00 ° C, the retained austenite is decomposed into bainite to expand the volume, and the tempering reduces the hardness of the annular portion to facilitate the elongation work. Yes, the second waist is
The method of inserting a large-diameter disc-shaped cutting tool according to claim 1, wherein the annular portion is subjected to expansion processing with a hammer or a pressure roller.