JP7554464B2 - Cutting blade - Google Patents

Description

The present invention relates to cutting blades used in shear-type crushers, etc.

As shown in Figs. 3 and 4, a shear-type crusher crushes materials by the shearing force generated by opposing rotating blades C like scissors. However, the cutting blades 1 used in the rotating blades C wear down due to friction during crushing as they are used, and the blades can chip due to the impact during crushing.
Therefore, the cutting blades 1 of the crusher are required to have high hardness and high toughness.
However, these are contradictory functions and it has been said that it is difficult to achieve both.

In addition, the only parts of the cutting blade 1 of the crusher that wear out are the parts that come into contact with the material to be crushed, and depending on the material to be crushed, only certain parts of the cutting blade 1 may wear out.

When the cutting blade 1 wears out and its crushing performance drops significantly, it is replaced with a new one, and the used cutting blade 1 is recycled. However, regenerating it through refining involves a large amount of _CO2 emissions, which is a major environmental burden.

In order to address this problem, a method of repairing the worn portion by build-up welding using arc welding has been widely used in the past (see, for example, Patent Document 1).
As a result, the welded portion of the cutting blade, which is built up by arc welding, ensures high hardness, and by making the base material out of a tough material, we have obtained a cutting blade that meets the requirements for performance as a crusher blade.

JP 2012-196610 A

However, the above-mentioned method of repairing the worn portion of the cutting blade by build-up welding using arc welding has the following problems.
- In the case of arc welding, only wire-type welding materials can be used, so there are limitations on the choice of welding materials.
- The area diluted by heat input and welding materials is large, and the area with reduced hardness is widespread.
- The amount of build-up increases because it is difficult to precisely control the thickness of the build-up layer, and in order to ensure the specified dimensional accuracy, 70 to 80% of the build-up amount needs to be machined off, which increases the amount of machining work after build-up welding.
In order to increase the hardness of the build-up weld, it is preferable to use a welding material with high hardness. However, if the hardness is too high (HRC 60 or higher), the machinability after build-up welding is significantly deteriorated, and it is necessary to use a welding material that is relatively easy to machine.
For these reasons, the method of build-up welding by arc welding is used when repairing worn portions of cutting blades, but has the problem that it is difficult to apply to new cutting blades.

The present invention aims to provide a cutting blade that overcomes the problems of heat input, dimensional accuracy, etc., associated with the conventional method of repairing worn parts of cutting blades by overlay welding using arc welding, and makes it possible to reinforce easily worn parts of new cutting blades.

In order to achieve the above object, the cutting blade of the present invention comprises:
A cutting edge portion protruding radially outward is provided,
The cutting edge portion has a tip edge portion that is sharpened in the direction of rotation,
A side edge portion is provided on the outer edge of the side surface including the cutting edge portion,
In the cutting blade, the upper surface of the tip edge portion and the side edge portion are formed with a build-up welded portion,
The build-up weld portion is characterized in that it is a laser build-up weld portion.

In this case, the laser build-up weld can be formed in a groove with a semicircular cross section formed in the base material of the cutting blade.

The laser build-up welded portion may also contain vanadium, chromium, and molybdenum.

The cutting blade of the present invention solves the problems associated with the conventional method of repairing worn portions of a cutting blade by build-up welding using arc welding, and provides the following advantageous effects.
・In the case of laser build-up welding, since the welding material is a powder, there are no restrictions on the choice of welding material, and the options for welding materials are wider. In addition to using commercially available products, it is possible to create original welding powders, making it possible to achieve unique hardness and toughness.
- The area diluted by heat input or welding material is small, and the area with reduced hardness is limited to a narrow range, thereby suppressing the reduction in hardness.
Since precise control of the thickness of the build-up layer is possible by controlling conditions such as the amount of welding material (powder) supplied and the welding speed, the amount of build-up can be kept to a minimum, and the cutting allowance required to ensure a specified dimensional accuracy can be controlled to be small (specifically, around 0.5 mm). This reduces the cutting allowance required for finishing processes in areas that affect performance such as interference (for example, finish polishing of the thickness of the cutting blade). This, combined with the fact that machining after build-up welding is not required for areas that do not affect performance such as interference, reduces the amount of machining work required after build-up welding.
- To increase the hardness of the welded build-up, it is preferable to use a welding material with high hardness, but since the process is only by grinding, it is possible to build up a high hardness (for example, HRC 60 or higher). This makes it possible to improve the wear resistance of the laser welded build-up by about 1.5 to 2 times compared to arc welding.
From the above, it can be said that the build-up welding method using laser welding is an optimal method not only for repairing worn portions of cutting blades, but also for application to new cutting blades.

FIG. 1(c) is a cross-sectional view taken along line A-A in FIG. 1(a); FIG. 1(d) is a cross-sectional view taken along line B-B in FIG. 1(b); FIG. 1(e) is a cross-sectional view taken along line C-C in FIG. 1(b); and FIG. 1(f) is a view corresponding to FIG. 1(e) when build-up welding is performed by arc welding. 1(a) is a plan view, FIG. 1(b) is a front view, and FIG. 1(c) is a view corresponding to FIG. 1(d). FIG. 2 is an explanatory diagram of a shear-type crusher to which the cutting blade of the present invention is applied. FIG. 2 is an explanatory diagram of a rotary blade of the shear-type crusher. 5(b) is a side view of the base material of the cutting blade according to a third embodiment of the present invention; FIG. 5(c) is an enlarged cross-sectional view of part A in FIG. 5(a); FIG. 5(d) is an enlarged cross-sectional view of part B in FIG. 5(b); and FIG. 5(e) is a front view of the cutting blade which has been build-up welded by laser welding.

The following describes an embodiment of the cutting blade of the present invention with reference to the drawings.

FIG. 1 shows a first embodiment of a cutting blade according to the present invention.
This cutting blade 1 is used, for example, in a rotary blade C of a shearing type crusher having a structure shown in Figs.

The shearing type crusher has been widely used in the past, and has two rotating shafts 3 each having a rectangular cross section arranged substantially parallel to each other with a fixed distance therebetween.
The rotating shafts 3 are rotatably installed and supported within a box-shaped casing 6 via bearings (not shown), and are configured to rotate inward (in the direction of the arrow in the figure) by a motor (not shown).

The rotary shaft 3 is provided with disk-shaped rotary blades C arranged alternately with spacers 4 interposed therebetween. The rotary blades C are attached with their side surfaces in close contact with each other.
Each rotary blade C is composed of a cutting blade 1 and a main body 2, and multiple (in this embodiment, six) cutting blades 1 are arranged on the outer peripheral surface 21 of the main body 2, and both are fixed at the bolt holes 15, 22 using bolts (not shown).
The cutting blade 1 of the rotary blade C has a fixed portion 11 and a cutting edge portion 12 protruding radially outward from the fixed portion 11. The cutting edge portion 12 has a tip edge portion 13 that is sharp in the direction of rotation and has the effect of drawing in the material to be processed and cutting or shearing it.
As a result, the material to be treated that is fed from above the casing 6 is crushed by the above-mentioned action of the cutting blades 1 of the rotary blades C and discharged downward.

A scraper 5 protrudes from the side of the box-shaped casing 6 toward the rotary blade C and the spacer 4 .
The scraper 5 serves to scrape off the material to be processed that is caught between the rotary blades C.

Incidentally, the cutting blade 1 of the rotary blade C wears down as it is used due to friction during crushing, and the blade portion may chip due to the impact during crushing, so that it becomes necessary to replace it after a certain period of use.
In order to extend this period, the cutting blade 1 of this embodiment is configured to form laser build-up welds 16, 17 on the upper surface of the tip edge portion 13 that is pointed toward the rotation direction of the cutting edge portion 12 and on the side edge portion 14 on the outer edge of the side surface including the cutting edge portion 12, as shown in Figure 1.

In this case, the base material of the cutting blade 1 can be preferably made of a material with toughness, such as chrome molybdenum steel (SCM440, etc.) or wear-resistant steel (HARDOX (registered trademark) 500).

Since powder welding material is used for the material of the laser build-up welds 16 and 17, there are no restrictions on the selection of welding material, and the selection of welding materials is widened.
In this embodiment, a powder welding material containing vanadium, chromium and molybdenum is used.
As a result, the build-up welds 16, 17 contain vanadium, chromium and molybdenum, and can have a high hardness (for example, HRC 60 to 65).

The thickness of the laser build-up welded parts 16, 17 can be controlled to the minimum necessary thickness, about 1 to 3 mm, preferably about 2 mm.
This makes it possible to control the cutting allowance of the laser build-up welded parts 16, 17 to be small (specifically, around 0.5 mm) in order to ensure a specified dimensional accuracy, and reduces the cutting allowance for finishing processing of parts that affect performance such as interference (for example, finish polishing of the thickness of the cutting blade 1). Combined with the fact that parts that do not affect performance such as interference do not require machining after build-up welding, the amount of machining work after build-up welding can be reduced.
In this embodiment, the laser build-up welded portion 16 is provided with a cutting allowance 18 for forming the tip edge portion 13 that is sharpened toward the direction of rotation of the cutting edge portion 12 .

FIG. 2 shows a second embodiment of the cutting blade of the present invention.
This cutting blade 1 has laser build-up welds 16, 17 formed on the upper surface of a tip edge portion 13 that is pointed toward the direction of rotation of the cutting edge portion 12 and on a side edge portion 14 on the outer edge of the side surface including the cutting edge portion 12, formed within a groove having a semicircular cross section formed in the base material of the cutting blade 1.
The semicircular grooves have a diameter of about 2 to 6 mm, preferably about 4 mm, and are formed in multiple rows, specifically, four rows on the upper surface of the tip edge portion 13 and two rows on the side edge portion 14.
As a result, in addition to the effects achieved by the first embodiment, the following effects are achieved.
- The number of welding passes can be reduced, reducing construction time and costs.
By forming the laser build-up welds 16, 17 in a groove having a semicircular cross section formed in the base material of the cutting blade 1, the laser build-up welds 16, 17 are integrated with the base material of the cutting blade 1 and will not peel off.
Other configurations and operations of this embodiment are similar to those of the first embodiment.

FIG. 5 shows a third embodiment of the cutting blade of the present invention.
The cutting blade 1 in the first and second embodiments described above is configured by dividing the cutting blade 1 into multiple pieces, but the form of the cutting blade of the present invention is not limited to this, and the configuration of the cutting blade 1 in the first and second embodiments can also be applied to an integral cutting blade 1 (rotary blade C) that is directly attached to a rotating shaft (not shown) with a rectangular cross section, as shown in Figure 3.

Specifically, this cutting blade 1 (rotary blade C) has laser build-up welds 16, 17 formed on the upper surface of the tip edge portion 13 that is pointed toward the rotation direction of the cutting edge portion 12 and on the side edge portion 14 of the outer edge of the side surface including the cutting edge portion 12, and are formed within grooves 17a, 17b with semicircular cross-sections formed in the base material of the cutting blade 1.
The semicircular groove has a diameter of about 2 to 6 mm, preferably about 4 mm, and is formed in multiple rows, specifically, four rows (not shown) on the upper surface of the tip edge portion 13 and two rows on the side edge portion 14.
This provides the same effects as those provided by the second embodiment.

The cutting blade of the present invention has been described above based on several embodiments, but the present invention is not limited to the configurations described in the above embodiments, and the configuration can be changed as appropriate within the scope of the spirit of the invention, such as by appropriately combining the configurations described in each embodiment.

The cutting blade of the present invention has the characteristics of resolving the problems of heat input, dimensional accuracy, etc., associated with the conventional method of repairing worn parts of cutting blades by overlay welding using arc welding, and making it possible to reinforce parts of new cutting blades that are prone to wear. Therefore, it can be suitably used for cutting blades used in the rotary blades of the two-shaft shear crusher described in the examples, and can also be widely applied to various cutting blades used in rotary blades of single-shaft or multi-shaft shear crushers other than two-shaft shear crushers, and can be used not only to reinforce parts of new cutting blades that are prone to wear, but also to repair worn parts of cutting blades.

REFERENCE SIGNS LIST 1 Cutting blade 11 Fixed portion 12 Blade tip portion 13 Tip edge portion 14 Side edge portion 16 Laser build-up welded portion 17 Laser build-up welded portion 18 Cutting allowance C Rotary blade

Claims (3)

A cutting edge portion protruding radially outward is provided,
The blade tip has a tip edge portion that is sharpened in the direction of rotation,
A side edge portion is provided on the outer edge of the side surface including the cutting edge portion,
A method for reinforcing a wear-prone portion of a new cutting blade by forming a build-up weld on an upper surface of the tip edge portion and on the side edge portion,
The build-up weld is formed by laser build-up to a thickness of 1 to 3 mm ,
The build-up welded portion of the side edge portion is recessed from the side surface of the cutting blade to form a stepped recessed surface along the side edge portion, so that the recessed surface remains at a predetermined width.
A method for reinforcing a portion of a new cutting blade that is easily worn, comprising: 2. The method for reinforcing a portion of a new cutting blade that is easily worn out, as described in claim 1, further comprising providing a cutting allowance on the underside of the tip edge portion having a laser build-up welded on the upper surface thereof, thereby forming a tip edge portion that is pointed toward the rotation direction of the cutting edge . 3. The method for reinforcing a portion of a new cutting blade that is easily worn out as set forth in claim 1 or 2, wherein the laser build-up welded portion contains vanadium, chromium and molybdenum.

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