JP2004337733A - Cutter for single spindle crusher and method for manufacturing it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve hardness and toughness of a cutter on a rotating side and a cutter on a fixed side in a single spindle crusher. <P>SOLUTION: A primary hardening process for hardening a raw material for the cutter 5 composed of a carbon steel wholly, a tempering process for tempering the raw material, and then, a secondary hardening process for partially hardening a part corresponding to a cutting edge part 16 of the raw material are practiced. By manufacturing the cutter 5 without performing a tempering process after the secondary hardening process, a hardness distribution wherein while the hardness of the cutting edge part 16 is made higher than the hardness of a base part 17, the hardness is decreased toward the base part 17 in the boundary part 18, is provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a cutting tool such as a rotary cutting tool and a fixed cutting tool used in a single-shaft crusher, and a method of manufacturing the same.
[0002]
[Prior art]
At present, crushing is usually performed by a crusher to make recyclable waste such as waste plastic into an easily recyclable form. There are various types of crushers, but most of them have a crushing action on a crushed material by a combination of a rotary blade mounted on an outer peripheral surface of a rotating body and a fixed blade provided at a fixed position. Or a two-shaft crusher that engages a gear-shaped blade to crush the object to be crushed. In addition, there are various types of single-shaft crushers as well, but usually, a combination of a square-column-shaped rotating blade and a fixed-side blade having a saw-tooth-shaped blade is used. .
[0003]
Examples of the material of the cutting tool provided in the crusher described above include chromium molybdenum steel (JIS code "SCM"), die steel (JIS code "SKD"), and high-speed tool steel (JIS code "SKH"). ), Cemented carbide and the like are mainly used.
[0004]
Chromium molybdenum steel is the cheapest of the above materials, but it has problems in toughness and it is difficult to increase hardness, so it is mainly used as a composite material for brazing cemented carbide etc. to the cutting edge. is there.
[0005]
Next, the die steel is most commonly used in the cutting tool provided in the above-described single-shaft crusher, and in particular, a so-called cold die steel is often used. In a crusher provided with a blade made of this material, waste plastic is generally applied as a crushed object, and is recycled, for example, as fuel for a power plant. However, if the hardness of the die steel is increased to 58 or more in terms of Rockwell hardness HRC, there is a risk that the steel will crack during use, and if the hardness is reduced, there is a problem that the life is shortened due to wear.
[0006]
Next, the high-speed tool steel has a higher hardness (around 65 in Rockwell hardness HRC) than the die steel, but the material cost is about three times as high as that of the die steel. Limited applications.
[0007]
Furthermore, cemented carbide has the highest hardness (around 70 in HRC), but has the highest material cost and therefore requires a high running cost. Tends to be limited.
[0008]
As described above, each material has advantages and disadvantages, and at present, each user sets the hardness of the blade according to the crushing conditions required by the company. In addition, high-speed tool steel and cemented carbide are superior to die steel in terms of hardness and toughness, but they cannot be used semi-permanently. In such a case, the current situation is that they must be reluctant to use them. From these facts, it is said that, at present, die steel is most suitable as a material for the blade provided in the crusher.
[0009]
[Patent Document 1]
JP-A-8-103678 [Non-Patent Document 1]
Japan Heat Treatment Technology Association, Heat Treatment Guidebook <Basic Edition>, First Edition, Ohkawa Publishing Co., Ltd., May 15, 1983, p. 48,150,152
[0010]
[Problems to be solved by the invention]
Generally, it is known that the toughness of a steel material decreases when its strength is increased (see page 48 of Non-Patent Document 1). For example, as for the cutting tool made of die steel, as described above, if the hardness is increased to HRC 58 or more, the toughness may be reduced and the tool may be broken during use. On the other hand, when the hardness is low, abrasion tends to occur, causing a problem that the life of the blade is shortened.
[0011]
In order to solve this problem, it is conceivable to apply a surface treatment such as carburizing, nitriding, or a coating treatment with TiC or TiN to harden only the surface of the blade. Is very thin, about 0.05 to 1 mm, and when used, the substrate is immediately exposed and abrasion starts, so that it has not been put to practical use.
[0012]
Further, when a normal quenching is performed on a cutting tool made of die steel, the entire cutting tool is quenched, so that the conflicting properties of hardness and toughness as described above cannot be both improved. It is also conceivable to perform partial hardening such as induction hardening only on the surface of the blade. However, such partial quenching is performed for medium-carbon steel (see, for example, page 150 of Non-Patent Document 1), and high-carbon steel such as die steel or high-speed tool steel is used. In the case of quenching, a problem that cracks occur in the quenching process is encountered. For this reason, it is common sense in the art that high-carbon steel cannot be partially quenched, such as induction hardening.
[0013]
Therefore, an object of the present invention is to provide a blade which is used in a single-shaft crusher and which can increase both hardness and toughness, and a method for manufacturing the same.
[0014]
[Means for Solving the Problems]
The present invention relates to a rotating body that is driven to rotate around a predetermined axis, a rotating blade mounted on the outer peripheral surface of the rotating body, and a rotating body provided at a fixed position facing the outer peripheral surface of the rotating body. And a fixed-side cutter for crushing the object to be crushed in cooperation with the rotary-side cutter according to the above, wherein the cutter is directed to a blade used as at least one of the rotary-side cutter and the fixed-side cutter. In order to solve the technical problems as described above, the present invention is characterized by having the following configuration.
[0015]
That is, the blade for a single-shaft crusher according to the present invention is provided with a cutting edge portion integrally formed of carbon steel, which performs a crushing action, and a base portion which is a portion to be attached to a rotating body or a fixed position. Is characterized in that the hardness is made higher than the hardness at the base, and a hardness distribution is provided at the boundary between the cutting edge and the base such that the hardness decreases toward the base.
[0016]
In the blade for a uniaxial crusher according to the present invention, the hardness at the cutting edge is 58 or more in Rockwell hardness (HRC), and the hardness at the base is 40 or more in Rockwell hardness (HRC). It is preferable that
[0017]
Die steel is preferably used as carbon steel constituting the blade for a single-shaft crusher according to the present invention.
[0018]
The present invention is also directed to a method for manufacturing a blade for a single-shaft crusher as described above. The method for manufacturing a blade for a single-shaft crusher according to the present invention includes a primary quenching step in which a material for a blade made of carbon steel is entirely quenched, and a step in which the material is baked after the primary quenching step. A tempering step, and after the tempering step, a secondary quenching step of quenching only the portion corresponding to the blade edge portion of the material, and the tempering step is not performed after the secondary quenching step. It is characterized by:
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a perspective view showing a main part of a single-shaft crusher 1 to which a blade according to the present invention is applied. The single-shaft crusher 1 includes, for example, a rotating body 4 that is driven to rotate in a direction indicated by an arrow 3 around a predetermined axis 2 that faces in the horizontal direction. A plurality of rotating blades 5 are mounted on the outer peripheral surface of the rotating body 4.
[0020]
FIG. 2 is a perspective view showing one rotating blade 5 alone. FIG. 3 is a cross-sectional view showing a main part of the single-shaft crusher 1 shown in FIG. 1 along a plane orthogonal to the axis 2, and FIG. 4 is an installation of the rotary blade 5 in FIG. It is sectional drawing which expands and shows a part.
[0021]
The rotary blade 5 has a quadrangular prism shape having four side surfaces 6 as well shown in FIG. A female screw hole 7 is provided in the center of the rotary blade 5. On the other hand, a plurality of mounting seats 8 are provided on the outer peripheral surface of the rotating body 4 so as to be distributed in the direction of the axis 2 and in the circumferential direction. As shown in FIGS. 3 and 4, the rotary blade 5 is fixed to each mounting seat 8 by screwing a bolt 9 inserted into the mounting seat 8 into the female screw hole 7. At this time, the rotary blade 5 is positioned forward of the mounting seat 8 with respect to the rotation direction indicated by the arrow 3, and the ridge portion between two adjacent side surfaces 6 is the outer peripheral surface of the rotary body 4. It is attached to project from
[0022]
The single-shaft crusher 1 further includes a fixed-side blade 11 provided on a fixed portion 10 as a fixed position facing the outer peripheral surface of the rotating body 4. The fixed-side blade 11 crushes an object to be crushed (not shown) in cooperation with the rotary-side blade 5 in accordance with the rotation of the rotating body 4. The fixed-side blade 11 includes the blade edge portion 12 that performs the crushing action as described above, and includes a base portion 14 that is a portion to be attached to the fixed portion 10. The base portion 14 is provided with a plurality of bolt holes 15 into which the bolts 13 screwed to the fixing portion 10 are inserted. The cutting edge portion 12 has a sawtooth shape having a triangular concave portion that provides a path through which the rotary blade 5 passes in accordance with the rotation of the rotating body 4 and a triangular convex portion at a position where the rotary blade 5 does not pass. . The distance between the fixed blade 11 and the rotary blade 5 is set to, for example, about 0.2 mm.
[0023]
As can be seen from the positional relationship between the fixed-side blade 11 and the rotary-side blade 5 described above, the blade edge portion 16 that performs the crushing action in the rotary-side blade 5 is located along the four side surfaces 6. Further, a base 17 serving as a mounting portion of the rotating body 4 to the mounting seat 8 is located at a central portion thereof, and the above-described female screw hole 7 is provided in the base 17.
[0024]
Since the cutting edge 16 of the rotary blade 5 is located along the four side surfaces 6, when the protruding ridge portion of the rotary blade 5 attached at the illustrated angle is worn, for example, the rotation is performed. If the side blade 5 is rotated every 90 degrees and the ridge portion where no abrasion or the like is generated is protruded and fixed again, the rotary blade 5 can be used basically four times.
[0025]
The rotating blade 5 and the fixed blade 11 provided in the single-shaft crusher 1 described above have the following features, respectively.
[0026]
FIG. 5 shows the rotary blade 5 in a cross-sectional view, in which the cutting edge portion 16, the base portion 17, and the boundary portion 18 thereof are separately illustrated by changing the direction of hatching.
[0027]
The rotating blade 5 is integrally formed of carbon steel, preferably die steel, and the strength at the cutting edge 16 is made higher than the hardness at the base 17, and at the boundary 18 between the cutting edge 16 and the base 17. The hardness distribution, that is, the gradation, is such that the hardness decreases toward the base 17. Here, the hardness at the cutting edge 16 is preferably 58 or more in Rockwell hardness (HRC), and the hardness at the base 17 is preferably 40 or more in Rockwell hardness (HRC).
[0028]
In FIG. 6, the fixed-side blade 11 is shown in a cross-sectional view, and the cutting edge portion 12, the base portion 14, and the boundary portion 19 thereof are separately illustrated by changing the direction of hatching.
[0029]
The fixed-side blade 11 is also integrally formed of carbon steel, preferably die steel. The hardness at the blade edge 12 is higher than the hardness at the base 14, and the boundary portion 19 between the blade edge 12 and the base 14 is formed. In the example, a hardness distribution, that is, a gradation, in which the hardness decreases toward the base portion 14 is given. The hardness of the fixed cutting edge 11 at the cutting edge 12 is 58 or more in Rockwell hardness (HRC), and the hardness at the base 14 is 40 or more in Rockwell hardness (HRC). Is preferred.
[0030]
In such a rotary blade 5, it is preferable that the depth 20 of the cutting edge 16 is about 5 to 10 mm. As for the fixed-side blade 11, it is preferable that the depth 21 of the blade portion 12 is about 40 mm. In FIGS. 5 and 6, the boundaries between the cutting edges 16 and 12, the boundary portions 18 and 19, and the bases 17 and 14 are clearly illustrated. However, the actual rotary blade 5 and the fixed blade are actually used. In FIG. 11, such a clear boundary line does not appear. Therefore, the above-described depths 20 and 21 of the cutting edge portions 16 and 12 may be understood to be, for example, the depth of a portion having HRC of 58 or more.
[0031]
According to the rotating blade 5 and the fixed blade 11 as described above, the hardness of the cutting edges 16 and 12 is increased, for example, while increasing the overall hardness to, for example, HRC40 or more and improving the wear resistance of the material itself. With an HRC of 58 or more, a sufficient crushing action can be exhibited. Further, even if the hardness at the cutting edge portions 16 and 12 is increased, the presence of the boundary portions 18 and 19 provided with the hardness distribution prevents the overall toughness of the rotary blade 5 and the fixed blade 11 from being reduced. can do.
[0032]
As a result, the rotating blade 5 and the fixed blade 11 can satisfy both conflicting properties such as hardness and toughness, and the life of the rotating blade 5 and the fixed blade 11 can be prolonged. The running cost of the single-shaft crusher 1 can be reduced.
[0033]
FIG. 7 shows an example of a heat pattern employed in manufacturing the above-described rotary blade 5 and fixed blade 11.
[0034]
With reference to FIG. 7, in order to manufacture the blade 5 or 11, a material for the blade 5 or 11 made of carbon steel is prepared. In this embodiment, a die steel is used as the carbon steel constituting the material. Die steel has an HRC of 30 or less in a raw material state before quenching.
[0035]
Next, the above-mentioned material is vacuum-heated, for example, in a furnace, whereby a first quenching step is performed in which the material is entirely quenched. In this primary quenching step, as shown in FIG. 7, vacuum heating is performed at 750 ° C. for 1 hour, then at 830 ° C. for 1 hour, and finally at 1030 ° C. for 2 hours.
[0036]
After the above-described primary quenching step, the material is oil-cooled, and then a tempering step of tempering the material is performed. In this tempering step, for example, a temperature of 540 ° C. is applied for 3.5 hours.
[0037]
When the above steps are completed, the raw material having a hardness of HRC 30 or less is made into a state having a hardness of HRC 40 or more.
[0038]
In the case of the conventional rotary-side blade and fixed-side blade, a product is obtained after the above-described steps are completed.
[0039]
The present invention is characterized in that a secondary quenching step is further performed after the above-described tempering step. In this secondary quenching step, only the portions corresponding to the respective cutting edge portions 16 and 12 in the material are quenched. In this secondary quenching step, for example, a temperature of 1000 to 1050 ° C. is applied, and preferably, a temperature higher than the temperature in the primary quenching step is applied.
[0040]
In the secondary quenching step, it is important that only the portions corresponding to the blade edge portions 16 and 12 are heated and the heating time is short. This is because if the heating time is prolonged, heat is applied to parts other than the specific part due to heat conduction. Therefore, in the secondary quenching step, it is preferable to apply induction heating such as induction quenching, which can instantaneously heat to a desired temperature and instantaneously stop the heating state.
[0041]
As a result of the above-described secondary quenching process, the hardness of the cutting edge portions 16 and 12 of the rotary blade 5 and the fixed blade 11 can be HRC 58 or more.
[0042]
Note that, as described above, quenching in which partial and rapid heating is performed, such as the above-described secondary quenching step, is usually performed for medium-carbon steel (see, for example, page 150 of Non-Patent Document 1). ), High carbon steels such as die steels or high speed tool steels were said to crack. However, as in the present invention, after the primary quenching step and the tempering step are completed, even if partial and rapid heating is performed in the secondary quenching step, no crack is generated. Has been confirmed by
[0043]
After the secondary quenching step, the rotary blade 5 and the fixed blade 11 are oil-cooled, for example. It is also important that the tempering step is not performed after the secondary quenching step. In this connection, according to quenching that performs partial and rapid heating such as induction quenching, since the residual stress is likely to cause cracking or breakage, tempering is usually required. (For example, see page 152 of Non-Patent Document 1). Nevertheless, according to the present invention, the rotary blade 5 and the fixed blade 11 that can sufficiently withstand use can be obtained without performing the tempering process after the secondary quenching process.
[0044]
In one experimental example, when the rotating blade 5 and the fixed blade 11 were manufactured by using a heat pattern as shown in FIG. 7 while using die steel as a material, the hardness of the bases 17 and 14 was HRC50 ± 1. Were obtained, and the hardness of HRC61-63 was obtained in the cutting edge portions 16 and 12.
[0045]
As described above, the present invention has been described with respect to the specific embodiments. However, various other modifications are possible within the scope of the present invention.
[0046]
For example, although the die steel is used as the material of the rotary blade 5 and the fixed blade 11, chromium molybdenum steel may be used, or the cost reduction effect of the present invention is reduced, It does not prevent speed tool steel from being used.
[0047]
Further, in the above-described embodiment, the configuration that is a feature of the present invention is adopted in both the rotating blade 5 and the fixed blade 11, but only one of the rotating blade 5 and the fixed blade 11 is provided. The characteristic configuration of the present invention may be adopted.
[0048]
【The invention's effect】
As described above, according to the blade for a single-shaft crusher according to the present invention, while being integrally formed of carbon steel, the hardness at the cutting edge is higher than the hardness at the base, and the cutting edge and the base are Is provided with a hardness distribution such that the hardness decreases toward the base, and contradictory properties such as hardness and toughness required as a blade can be satisfied at the same time.
[0049]
In the blade according to the present invention, when the hardness at the cutting edge is 58 or more in Rockwell hardness (HRC) and the hardness at the base is 40 or more in Rockwell hardness (HRC), the entire blade is hardened. While exhibiting abrasion resistance sufficiently, it is possible to provide sufficient hardness for the crushing action at the cutting edge, and to prolong the life of the blade, and as a result, the running of the single-shaft crusher Cost can be reduced.
[0050]
When die steel is used as the carbon steel constituting the cutting tool according to the present invention, the cutting tool can be made practically excellent in all aspects of hardness, toughness and cost.
[0051]
ADVANTAGE OF THE INVENTION According to the manufacturing method of the blade for uniaxial crushers according to the present invention, a primary quenching step in which the material for the blade made of carbon steel is entirely quenched, and then a tempering step in which the material is tempered. Then, a secondary quenching step is performed in which only the portion corresponding to the blade edge portion of the material is quenched, and after the secondary quenching step, the tempering step is not performed. The cutting tool according to the present invention can be manufactured reliably and easily.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a main part of a single-shaft crusher 1 to which a blade according to the present invention is applied.
FIG. 2 is a perspective view showing the rotary blade 5 shown in FIG. 1 alone;
FIG. 3 is a sectional view showing a main part of the single-shaft crusher 1 shown in FIG. 1 along a plane orthogonal to an axis 2;
FIG. 4 is a cross-sectional view showing, on an enlarged scale, a portion where the rotary blade 5 shown in FIG. 3 is mounted.
FIG. 5 is a cross-sectional view of the rotating blade 5 showing a cutting edge portion 16, a base portion 17, and a boundary portion 18, which are features of the present invention.
FIG. 6 is a cross-sectional view of the fixed-side blade 11 showing a cutting edge portion 12, a base portion 14, and a boundary portion 19, which are features of the present invention.
FIG. 7 is a diagram showing an example of a heat pattern employed in the method of manufacturing a blade according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Single-shaft crusher 2 Axis line 4 Rotating body 5 Rotating side blade 6 Side surface 7 Female screw hole 8 Mounting seat 9, 13 Bolt 10 Fixed part 11 Fixed side blade 12,16 Blade edge 14,17 Base 18,19 Boundary part

Claims (4)

A rotating body that is driven to rotate around a predetermined axis, a rotating blade mounted on an outer peripheral surface of the rotating body, and a rotating blade that is provided at a fixed position facing the outer peripheral surface of the rotating body and rotates according to the rotation of the rotating body. A fixed-side blade for crushing the object to be crushed in cooperation with the rotating-side blade, in a uniaxial crusher, a blade used as at least one of the rotating-side blade and the fixed-side blade,
It is provided with a cutting edge, which is integrally formed of carbon steel, and which performs a crushing action, and a base which is a part to be attached to the rotating body or the fixed position, wherein the hardness at the cutting edge is higher than the hardness at the base. And a hardness distribution such that hardness decreases toward the base portion at a boundary portion between the blade tip portion and the base portion. The uniaxial crushing according to claim 1, wherein the hardness at the cutting edge is 58 or more in Rockwell hardness (HRC), and the hardness at the base is 40 or more in Rockwell hardness (HRC). Machine knife. The blade for a uniaxial crusher according to claim 1 or 2, wherein the carbon steel is a die steel. A method for producing a blade for a uniaxial crusher according to any one of claims 1 to 3,
A primary quenching step of entirely quenching the material for the cutting tool made of carbon steel;
After the primary quenching step, tempering the material, a tempering step,
After the tempering step, a secondary quenching step of quenching only a portion corresponding to the blade edge portion of the material,
After the secondary quenching step, no tempering step is performed.
A method for manufacturing blades for single-shaft crushers.

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