CUTTING MEMBER AND MANUFACTURING METHOD THEREOF

Abstract

Disclosed herein is a method of manufacturing a cutting member that has a first portion for supporting, a second portion for forming a cutting edge, and a third portion connecting the first and second portion; the method includes: providing a first metal material used for forming the first portion; providing a second metal material used for forming the second portion; welding the first and second metal material with high energy density beam to form the third portion at the welding site; performing heat treatment on a cutting member blank obtained after welding. Also disclosed is a cutting member, the first portion of a first metal material; the second portion of a second metal material; after welding, the metallographic structure of the third portion and its nearby metallographic structure are substantially free of holes. The body of the manufactured cutting member has good toughness, the cutting edge has high hardness, and the body and cutting edge are not easily broken and have long service life.

Claims

1. A method of manufacturing a cutting member, wherein: the cutting member has a first portion for supporting, a second portion for forming a cutting edge, and a third portion connecting the first portion and the second portion; the manufacturing method comprises: providing a first metal material which is used for forming the first portion and has a first side; providing a second metal material which is used for forming the second portion and has a second side; welding the first side of the first metal material and the second side of the second metal material with high energy density beam to form the third portion at the welding site; and obtaining a cutting member blank after welding, and performing heat treatment on the cutting member blank.

2. The method of manufacturing a cutting member according to claim 1, wherein the high energy density beam welding is laser, electron beam or ion beam welding.

3. The method of manufacturing a cutting member according to claim 2, wherein the high energy density beam welding is pulse laser welding, and the wavelength of the laser light is 1064 nm, the moving rate of the laser light is 550 mm/s; or the high energy density beam welding is continuous laser welding, the continuous laser light is generated by a rare-earth doped laser, and the wavelength of the laser light is 1070 nm10 nm, the moving rate of the laser light is 550 mm/s.

4. (canceled)

5. (canceled)

6. The method of manufacturing a cutting member according to claim 2, wherein the first metal material is hardened stainless steel; and the second metal material is tool steel.

7. The method of manufacturing a cutting member according to claim 6, wherein the first metal material is martensitic stainless steel having a carbon content of 0.10.7%; and the second metal material is high-speed tool steel having a carbon content of not less than 0.7% or alloy tool steel having a carbon content of not less than 0.8%; the high-speed tool steel having a carbon content of not less than 0.7% or the alloy tool steel having a carbon content of not less than 0.8% contains at least one or more of alloy elements such as W, Cr, Mo, V and Co.

8. (canceled)

9. The method of manufacturing a cutting member according to claim 6, wherein the manufacturing method further includes the following step before welding: cutting the first metal material and the second metal material, and the minimum width of the second metal material perpendicular to the first side is 0.3 mm.

10. A method of manufacturing a cutting member, wherein, the cutting member has a first portion for supporting, a second portion for forming a cutting edge, and a third portion connecting the first portion and the second portion; the manufacturing method comprises: providing a first metal material which is used for forming the first portion and has a first side; providing a second metal material which is used for forming the second portion and has a second side; wherein the first metal material is martensitic stainless steel having a carbon content of 0.10.7%; and the second metal material is high-speed tool steel having a carbon content of not less than 0.7% or alloy tool steel having a carbon content of not less than 0.8%; welding the first side of the first metal material and the second side of the second metal material with high energy density beam to form the third portion at the welding site; and obtaining a cutting member blank after welding, and performing heat treatment on the cutting member blank, the heat treatment comprising: raising and holding the temperature of the cutting member blank in stages; quenching the cutting member blank after temperature raising; and tempering the cutting member several times after quenching.

11. The method of manufacturing a cutting member according to claim 10, wherein the heat treatments are all performed under vacuum before the quenching, and the degree of vacuum in a vacuum heating chamber is not more than 200 Pa.

12. The method of manufacturing a cutting member according to claim 11, wherein the steps of raising and holding the temperature in stages comprises: raising the cutting member blank to a first temperature at a first rate and performing a first temperature holding; raising the cutting member blank from the first temperature to a second temperature at a second rate lower than the first rate and performing a second temperature holding; and raising the cutting member blank from the second temperature to a third temperature at a third rate not higher than the second rate and performing a third temperature holding; wherein the first rate is 9.51 C./min, the first temperature is 620680 C., and the first temperature holding is holding the temperature for 6090 min; the second rate is 70.5 C./min, the second temperature is 800850 C., and the second temperature holding is holding the temperature for 6090 min; and the third rate is 60.5 C./min, the third temperature is 11001250 C., and the third temperature holding is holding the temperature for 60120 min.

13. (canceled)

14. (canceled)

15. The method of manufacturing a cutting member according to claim 10, wherein the quenching is vacuum gas quenching, the pressure of the inert gas in the heating chamber is at least 0.5 bar, and the temperature in the heating chamber is reduced to below 100 C.; or the quenching is vacuum oil quenching, and the temperature of the vacuum quenching oil used is in the range of 5080 C.

16. (canceled)

17. The method of manufacturing a cutting member according to claim 10, wherein the second metal material adopts high-speed tool steel having a carbon content of not less than 0.7%, and the step of tempering comprises: raising the cutting member blank after quenching to a fourth temperature and performing a fourth temperature holding; wherein the fourth temperature is 500560 C., the fourth temperature holding is holding the temperature for 2 hours, the tempering is performed three times, and the cutting member blank is air-cooled to a room temperature before every tempering and then raised to the fourth temperature.

18. (canceled)

19. The method of manufacturing a cutting member according to claim 10, wherein the second metal material adopts alloy tool steel having a carbon content of not less than 0.8%, and the step of tempering comprises: raising the cutting member blank after quenching to a fifth temperature and performing a fifth temperature holding; wherein the fifth temperature is 180260 C., the fifth temperature holding is holding the temperature for 2 hours, the tempering is performed twice, and the cutting member blank is air-cooled to a room temperature before every tempering and then raised to the fifth temperature.

20. (canceled)

21. A cutting member, wherein: the cutting member has a first portion for supporting, a second portion for forming a cutting edge, and a third portion connecting the first portion and the second portion; the first portion is comprised of a first metal material, and the first metal material is hardened stainless steel and has a first side; the second portion is comprised of a second metal material, the second metal material is tool steel and has a second side; and the third portion is formed by welding the first side of the first metal material and the second side of the second metal material with high energy density beam; after welding, the metallographic structure of the first portion near the third portion, the metallographic structure of the third portion, and the metallographic structure of the second portion near the third portion are substantially free of holes.

22. The cutting member according to claim 21, wherein after welding, the metallographic structure of the first portion near the third portion contains martensite, ferrite and carbide structures, and the metallographic structure of the second portion near the third portion contains cryptocrystalline martensite and partial carbide structures.

23. The cutting member according to claim 22, wherein the metallographic structure of the first portion near the third portion makes the tensile strength thereat is not lower than the tensile strength of the first metal material; and the metallographic structure of the second portion near the third portion makes the tensile strength thereat is not lower than the tensile strength of the second metal material.

24. The cutting member according to claim 23, wherein heat treatment is performed on the cutting member to improve the hardness, the hardness of the first portion after heat treatment is between 36-54 HRC and the hardness of the second portion is between 58-72 HRC.

25. The cutting member according to claim 24, wherein the second portion has a first edge for cutting, and the first edge is smooth or sawtooth-shaped; the cutting member has a polygonal shape.

26. (canceled)

27. The cutting member according to claim 25, wherein the cutting member is triangular in shape and has a second edge and a third edge intersecting both ends of the first edge, respectively, and the second edge and the third edge also intersect with each other; the first portion and the second portion extend from the second edge to the third edge; the second edge consists of at least two line segments, including at least a continuous curve; the at least two line segments are mathematically continuously differentiable.

28. (canceled)

29. (canceled)

30. The cutting member according to claim 27, wherein the ratio of the maximum width of the second portion to the maximum width of the first portion is 1:151:3.

31. A cutting tool, wherein the cutting tool comprise the cutting member according to claim 21.

32. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0066] FIG. 1 is a schematic view of a preferred embodiment of a cutting member of the present invention, which is specifically a blade.

[0067] FIG. 2 is a metallographic structure near a third portion of a preferred embodiment of a cutting member of the present invention.

[0068] FIG. 3 and FIG. 4 are schematic views of an embodiment of a cutting member of the present invention, which is specifically a blade of a utility knife.

[0069] FIG. 5 is a schematic view of another embodiment of a cutting member of the present invention, which is specifically a blade of an art knife.

[0070] FIG. 6 and FIG. 7 are schematic views of still another embodiment of a cutting member of the present invention, which is specifically a machete.

[0071] FIG. 8 and FIG. 9 are schematic views of further another embodiment of a cutting member of the present invention, which are specifically a saw blade of a hand saw and a saw blade of a wallboard saw.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0072] The cutting member according to the present invention is used for cutting an object, including a support portion, a cutting edge portion and a weld, the support portion plays a role of supporting the cutting edge portion, the cutting edge portion may be used for cutting, and the weld is formed by welding for connecting the support portion and the cutting edge portion.

[0073] FIG. 1 shows a cutting member according to an embodiment of the present invention, which is a blade. The blade defines a first edge 1, a second edge 2 and a third edge 3, wherein the first edge 1 and the second edge 2 have a first intersection 11, the first edge 1 and the third edge 3 have a second intersection 12, and the second edge 2 and the third edge 3 have a third intersection 13. In this specific implementation, the blade exhibits a triangular configuration.

[0074] The blade has a first portion 4 for supporting and a second portion 5 for forming a cutting edge. The first portion 4 extends along the second edge 2 towards the third edge 3 and the second portion 5 extends between the first edge 1 and the first portion 4 towards the third edge 3. There is a third portion 6, i.e., a weld formed by welding between the first portion 4 and the second portion 5, and the third portion 6 connects the first portion 4 and the second portion 5.

[0075] The first portion 4 is made of a first metal material which has relatively high toughness, and martensite stainless steel is selected. In a preferred embodiment, the martensitic stainless steel has a carbon content of 0.10.7%, and may be selected from standardized martensitic stainless steels of the following brands (Chinese brand/U.S. brand), including but not limited to 2Cr13/420, 3Cr13/420, 4Cr13 and 7Cr17/440, and the like.

[0076] The second portion 5 is made of a second metal material which has relatively high hardness/abrasion resistance, and high-speed tool steel or alloy tool steel is selected. In a preferred embodiment, the high-speed tool steel has a carbon content of not less than 0.7% and contains at least one or more of the alloy elements such as W, Cr, Mo, V and Co, and may be selected from standardized high-speed tool steels of the following brands (Chinese brand/U.S. brand), including but not limited to W18Cr4V/T1, W18Cr4V2Co8/T5, W12Cr4V5Co5/T15, W6Mo5Cr4V2/M2, W2Mo9Cr4V2/M7 and W2Mo9Cr4VCo8/M42. In still another preferred embodiment, the alloy tool steel has a carbon content of not less than 0.8%, and may be selected from standardized alloy tool steels of the following brands (Chinese brand/U.S. brand), including but not limited to Cr12Mo1V1/D2, Cr12/D3 and Cr5Mo1V/A2.

[0077] A third portion 6 of the blade is formed when the first metal material and the second metal material are welded for connection. The third portion 6 is a weld between the first portion and the second portion. Observing the metallographic structure of the weld, as shown by a in FIG. 2, there is substantially no holes formed, indicating that the welding effect of the weld is good. At the first portion 4 near the third portion 6, as shown by b in FIG. 2, the metallographic structure thereat after welding contains martensite, ferrite and carbide structures. At the second portion 5 near the third portion 6, as shown by c in FIG. 2, the metallographic structure thereat after welding contains cryptocrystalline martensite and partial carbide structures. The above-described metallographic structures ensure that the tensile strengths of the first portion 4 and the second portion 5 near the third portion 6 are at least comparable to that of the base material. The metallographic structures of the third portion 6, the first portion 4 near the third portion 6, and the second portion 5 near the third portion 6 are substantially free of holes, indicating that the structure strength at the welding site is high and is not easily broken, therefore, it is no more likely to occur that the first portion and the second portion are broken off during use, extending the service life of the blade.

[0078] In a preferred embodiment, the ratio of the width of the second portion 5 to the maximum width of the first portion 4 is between 1:15 and 1:3, such as 1:15, 1:10, 1:5 or 1:3. The ratio in this range ensures that the second portion 4 can be welded to the first portion 5 and that the second portion 4 is not too wide to weaken the toughness of the first portion 5, thereby causing the entire blade to be easily broken. This ensures the hardness and abrasion resistance of the cutting edge formed by the second portion and also ensures high toughness of the first portion.

[0079] In still another embodiment, the first edge 1 of the blade consists of at least two line segments, including a continuous curve. The curve formed by all the line segments is mathematically continuously differentiable. With such cutting edge curve, in combination with the triangular blade structure, a good cutting effect can be produced.

[0080] It will be understood by those skilled in the art that the cutting member of the present invention may also have various shapes and configurations, for example, a blade of a utility blade as shown in FIGS. 3 and 4, which has trapezoidal appearance and includes a first portion 21, 31 for supporting, a second portion 22, 32 for forming a cutting edge, and a third portion 23, 33 formed by welding between the first portion and the second portion, and the first portion 21 or 31 has grooves or holes for cooperating with other portions of the utility knife. The cutting member may also be an art knife as shown in FIG. 5, which has a parallelogram shape and includes a first portion 41 for supporting, a second portion 42 for forming a cutting edge, and a third portion 43 formed by welding between the first portion and the second portion. The cutting member may also be a machete as shown in FIGS. 6 and 7, the first portion 51 or 61 thereof has an elongated protruding handle connecting portion 511 and 611, and the material of the handle connecting portion may be the same as or different from the material of the first portion. The cutting member may also be a saw blade of a hand saw or a wallboard saw as shown in FIGS. 8 and 9, and the second portion thereof which forms a cutting edge has a sawtooth-shaped edge formed by grinding or the like. The sawtooth shape may be a commonly used sawtooth shape in the art, such as double grinding tooth or triple grinding tooth. In these different embodiments, the metallographic structures of the material of the first portion, the material of the second portion, the third portion after welding and the nearby portion of the third portion after welding are as described in the foregoing embodiments and will not be described here again.

[0081] It will be understood by those skilled in the art that the cutting member of the present invention may also have various other shapes and configurations other than those described above.

[0082] Another aspect of the present invention provides a method of manufacturing a cutting member as described above, in a specific embodiment, the manufacturing method includes the steps of: 1) blanking a first metal material and a second metal material, 2) welding with high energy density beam, such as laser, electron beam or ion beam welding, 3) performing heat treatment on the cutting member blank after welding, and 4) grinding the cutting member after heat treatment to form a finished product.

[0083] In one embodiment of the manufacturing method of the present invention, the first metal material adopts martensitic stainless steel with a carbon content of 0.10.7%, and the second metal material adopts high-speed tool steel with a carbon content of not less than 0.7%.

[0084] First, the first metal material and the second metal material are respectively blanked and cut into shapes substantially corresponding to the first portion and the second portion of the finished cutting member. The cutting may be performed using wire cutting or high-speed punch press, and may also be performed using other cutting methods conventionally used in the art. The first metal material after cutting has a relatively flat first side, and the second metal material after cutting has a relatively flat second side.

[0085] Then, the first side of the first metal material and the second side of the second metal material after cutting are welded with pulse laser light having a wavelength of 1064 nm and a moving rate of 550 mm/s. In another embodiment of the present invention, it is also possible to weld with a continuous laser light having a wavelength of 1070 nm10 nm and a moving rate of 550 mm/s, and the continuous laser light is generated by a rare-earth doped laser. In addition, it is also possible to weld with electron beam and ion beam.

[0086] Thereafter, heat treatment is performed on the cutting member blank after welding.

[0087] The heat treatment includes 1) temperature raising and holding; 2) quenching; and 3) tempering. Wherein, the temperature raising and holding and quenching are performed in a vacuum oven, and the degree of vacuum in the vacuum heating chamber is not greater than 200 Pa before quenching.

[0088] The heat treatment is specifically:

[0089] 1) temperature raising and holding: raising the temperature to 620680 C. at a rate of 9.51 C./min and holding the temperature for 6090 min; and then raising the temperature to 800850 C. at a rate of 70.5 C./min and holding the temperature for 6090 min; and then raising the temperature to 11001250 C. at a rate of 60.5 C./min and holding the temperature for 60120 min. In a preferred embodiment, raising the temperature to 650 C. at a rate of 9.5 C./min and holding the temperature for 90 min; and then raising the temperature to 800850 C. at a rate of 7 C./min and holding the temperature for 6090 min; and then raising the temperature to 11001250 C. at a rate of 6 C./min and holding the temperature for 60120 min;

[0090] 2) quenching: using the vacuum gas quenching, filling inert gas into the heating chamber so that the pressure of the inert gas in the heating chamber is at least 0.5 bar, and cooling to below 100 C. (which means that the display temperature of the vacuum oven is below 100 C.). In another embodiment, the quenching adopts vacuum oil quenching, and the temperature of the vacuum quench oil used is in the range of 5080 C.; and

[0091] 3) tempering: air-cooling the cutting member blank after quenching to room temperature, and then raising the temperature to 500560 C., holding the temperature for 2 hours, and then repeating such steps twice, that is, the tempering is performed three times in total.

[0092] Finally, the cutting member blank after heat treatment is grinded in size and shape. The grinding may be performed using the methods conventionally used in the art, for example, by means of a grinder.

[0093] In another embodiment of the manufacturing method of the present invention, the first metal material adopts martensitic stainless steel having a carbon content of 0.10.7%, and the second metal material adopts alloy tool steel having a carbon content of not less than 0.8%.

[0094] Blanking, welding, the steps of temperature raising and quenching in the heat treatment, and the final grinding step are as described in the previously specific implementation of the manufacturing method and will not be described again.

[0095] The specific steps of tempering in the process of the heat treatment is: air-cooling the cutting member blank after quenching to room temperature, and then raising the temperature to 180260 C., holding the temperature for 2 hours, and then repeating such steps once, that is, the tempering is performed twice in total.

[0096] Furthermore, in still another embodiment of the manufacturing method, the heat treatment of the cutting member blank after welding may not be performed under vacuum.

[0097] With the manufacturing method of the above-described specific implementations or embodiments, the third portion is obtained after welding, and the metallographic structure thereof is substantially free of holes (as shown by a in FIG. 2), which indicates that with the welding manner in the specific implementations, the effect of welded connection is good, and the third portion formed by welding is not easily broken. The first portion near the third portion after welding forms metallographic structure containing martensite, ferrite and carbide structures, which improves the tensile strength thereat so that it is at least not lower than the original tensile strength of the first metal material used in the first portion. The second portion near the third portion after welding forms metallographic structure containing cryptocrystalline martensite and partial carbide structures, which improves the tensile strength thereat so that it is at least not lower than the original tensile strength of the second metal material used in the second portion.

[0098] After heat treatment, the first portion has a hardness of 36-54 HRC, and such hardness imparts better toughness to the first portion, so that the cutting member is not easily broken. The second portion has a hardness of 58-72 RHC, which imparts good abrasion resistance to the second portion, making the service life of the cutting edge longer.

[0099] A further aspect of the present invention provides a cutting tool including the cutting member described above. The cutting tool can be a fruit knife, a utility knife, a folding knife, an art knife, a single knife, a hand saw, a wallboard saw or a sweep saw.

[0100] The single knife formed with a blade manufactured using the method of the present invention, when compared to the existing single knife, has sharpness and durability as following:

TABLE-US-00001 TABLE 1 Sharpness Durability No. Item (mm) (mm) 1 the single knife with a cutting 35.8 303.6 member manufactured according to the manufacturing method of the present invention 2 the existing single knife 29.6 94.1

[0101] It can thus be seen that the durability of the single knife with a cutting member according to the embodiment of the present invention has increased several times than that of the existing single knife.

[0102] The preferred specific embodiments of the present invention have been described in detail above. It is to be understood that numerous modifications and variations can be made by those ordinary skilled in the art in accordance with the concepts of the present invention without any inventive effort. Hence, the technical solutions that can be derived by those skilled in the art according to the concepts of the present invention on the basis of the prior art through logical analysis, reasoning and limited experiments should be within the scope of protection defined by the claims.