Cutting tool and method for manufacturing same

Abstract

Provided is a cutting tool and a manufacturing method thereof. The cutting tool may include: a body portion made of a base material or a composite material; and a cutting edge portion made of the composite material and bonded to the body portion. Among them, the composite material includes the base material and hard ceramic particles uniformly distributed in the base material, and the hard ceramic particles have a melting point higher than that of the base material. This cutting tool has improved lasting sharpness.

Description

Technical Field

[0001] The invention relates to the field of cutting tools, and more particularly, to a cutting tool and a manufacturing method thereof. Background Art

[0002] Cutting tools are one of the instruments that people often need to use in daily life. The sharpness of a cutting tool is a major factor in considering the performance of the cutting tool. Currently, the common cutting tools on the market are martensitic stainless steel cutting tools, which are one of the cutting tools with relatively good performance. However, such cutting tools still have the following disadvantages: The cutting edge of the cutting tool is usually a relatively thin conical structure. During daily use, the cutting edge will inevitably impact on hard materials (for example, a cutting board, a bone). After being used for a period of time, an obvious bending (i.e., edge curling) phenomenon will occur at the cutting edge. In addition, the sharpness of the cutting edge of a martensitic stainless steel cutting tool will also significantly decrease due to wear after being used for a relatively short period of time.

[0003] Therefore, how to make a cutting tool remain sharp for a long time is a direction that has been explored in the field of cutting tool manufacturing technology. Summary of the Invention

[0004] The purpose of the present invention is to provide a cutting tool and a manufacturing method thereof to solve the problem of insufficient long-term sharpness of the cutting tool in the prior art.

[0005] The cutting tool according to the concept of the present invention includes: a main body part made of a base material or a composite material; and a cutting edge part made of the composite material and joined to the main body part, wherein the composite material includes the base material and hard ceramic particles uniformly distributed in the base material, and the hard ceramic particles have a melting point higher than that of the base material.

[0006] In an embodiment, the base material includes at least one of martensitic stainless steel, austenitic stainless steel, and duplex stainless steel.

[0007] In an embodiment, the hard ceramic particles include at least one of tungsten carbide, silicon carbide, zirconia, alumina, chromium carbide, titanium oxide, titanium carbide, and silicon nitride.

[0008] In an embodiment, the particle size of the hard ceramic particles is in the range of 20 μm - 100 μm.

[0009] In an embodiment, based on the total mass of the composite material, the mass percentage of the base material is 70% - 90%, and the mass percentage of the hard ceramic particles is 10% - 30%.

[0010] The method for manufacturing the above-mentioned tool according to an embodiment of the present invention includes: mixing matrix material powder and hard ceramic particles evenly through a ball milling mixing process to manufacture a composite material slurry, and preparing dry composite material powder through a spray powder preparation method; pressing the composite material powder in a mold to form a tool blank or pressing the matrix material powder and the composite material powder in a mold to form a tool blank, wherein the part of the tool blank corresponding to the cutting edge of the tool is made of the composite material, and the part of the tool blank corresponding to the main body part of the tool is made of the matrix material or the composite material; sintering the tool blank in a protective atmosphere so that the matrix material melts and the hard ceramic particles remain in a particulate state; and grinding and sharpening the tool blank after cooling.

[0011] In an embodiment, the particle sizes of both the matrix material powder and the hard ceramic particles are in the range of 20 μm - 100 μm.

[0012] In an embodiment, the mass percentage of the matrix material powder in the composite material powder is 70% - 90%, and the mass percentage of the hard ceramic particles is 10% - 30%.

[0013] In an embodiment, the molding pressure when pressing to form the tool blank is 200 MPa - 500 MPa.

[0014] The method for manufacturing the above-mentioned tool according to another embodiment of the present invention includes: manufacturing the main body part and the cutting edge separately, and then combining the cutting edge with the main body part.

[0015] According to the concept of the present invention, the cutting edge of the tool includes a matrix material and hard ceramic particles evenly distributed in the matrix material. The hard ceramic particles are evenly dispersed at the cutting edge, which can significantly improve the wear resistance of the cutting edge, reduce the wear of the tool during use, and thus improve the lasting sharpness of the tool. In addition, the evenly dispersed hard ceramic particles can form a micro-serrated structure at the cutting edge, enhancing the strength and cutting ability of the tool, making the tool less likely to curl, and therefore capable of improving the lasting sharpness of the tool. Description of the Drawings

[0016] Figure 1 is a schematic diagram schematically showing the structure of a tool according to an embodiment.

[0017] Figure 2 is according to an embodiment of the present application Figure 1 partial enlarged view of. Detailed Embodiments

[0018] Now, the present invention will be described more fully hereinafter with reference to exemplary embodiments. However, the present invention can be implemented in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art.

[0019] Hereinafter, Figures 1 to 2 a detailed description will be given of a cutting tool according to the concept of the present invention.

[0020] Figure 1 is a schematic diagram schematically showing the structure of a cutting tool according to an embodiment. Figure 2 is according to an embodiment of the present application Figure 1 partial enlarged view of.

[0021] Referring to Figure 1 , the cutting tool 100 according to the embodiment includes a main body portion 10 and a cutting edge portion 20 coupled to the main body portion 10. For example, the main body portion 10 and the cutting edge portion 20 may be integrally formed.

[0022] According to an embodiment of the present disclosure, the main body portion 10 may include a base material or a composite material (the composite material is as described hereinafter), or be made of a base material or a composite material. For example, the main body portion 10 is composed of a base material or a composite material. The base material includes at least one of martensitic stainless steel, austenitic stainless steel, and duplex stainless steel. The melting point of the base material is generally in the range of 1300°C - 1500°C.

[0023] The cutting edge portion 20 may include a composite material or be made of a composite material. For example, the cutting edge portion 20 may be composed of a composite material. The composite material may include a base material (as described above) and hard ceramic particles uniformly distributed in the base material, wherein the hard ceramic particles may include at least one of tungsten carbide (WC, melting point 2870°C), silicon carbide (SiC, melting point 2700°C), zirconia (ZrO2, melting point 2700°C), alumina (Al2O3, melting point 2054°C), chromium carbide (Cr7C3, melting point 1890°C), titanium oxide (TiO2, melting point 3140°C), titanium carbide (TiC, melting point 3140°C), and silicon nitride (Si3N4, melting point 1900°C). The hard ceramic particles have a melting point higher than that of the base material.

[0024] As Figure 2As shown, the hard ceramic particles are evenly dispersed at the cutting edge 20, and the particle size of the hard ceramic particles can be 20μm - 100μm, or 30μm - 90μm, or 40μm - 80μm, or 50μm - 70μm. The hard ceramic particles have higher hardness and wear resistance than the matrix material. Therefore, the uniform distribution of the hard ceramic particles in the matrix material can significantly enhance the wear resistance of the cutting edge, reducing the wear of the tool 100 during use. It should be noted that when the particle size of the hard ceramic particles is less than 20μm, the improvement of the wear resistance of the cutting edge 20 may not be obvious; when the particle size of the hard ceramic particles is greater than 100μm, the bonding effect with the matrix material may be poor, which may affect the improvement of the wear resistance of the tool 100. The hard ceramic particles can have various regular or irregular shapes. The hard ceramic particles are evenly dispersed inside and on the outer surface of the cutting edge 20. The hard ceramic particles exposed on the outer surface of the cutting edge 20 present a micro-protrusion state from the surface of the cutting edge 20. Therefore, a micro-serrated structure can be formed on the cutting edge surface, improving the strength and cutting ability of the tool, making the tool not easily roll the edge, and thus further improving the lasting sharpness of the tool.

[0025] The composite material included in the main body 10 and the composite material included in the cutting edge 20 can include the same hard ceramic particles (for example, both include TiC), or can include different hard ceramic particles. For example, the composite material included in the main body 10 includes TiC, and the composite material included in the cutting edge 20 includes Si3N4.

[0026] In the composite material, the mass percentage of the matrix material can be 70% - 90%, and the mass percentage of the hard ceramic particles can be 10% - 30%. If the mass percentage of the hard ceramic particles is less than 10%, it may be difficult to form a micro-serrated structure due to the sparse distribution of the hard ceramic particles, resulting in an insignificant improvement in wear resistance. If the mass percentage of the hard ceramic particles is greater than 30%, the toughness may become poor due to excessive modification, making the cutting edge prone to chipping.

[0027] Next, the method for manufacturing the above tool 100 will be described in detail.

[0028] First, a composite material powder is manufactured by uniformly mixing matrix material powder and hard ceramic particles through a wet ball milling mixing process as follows: Hard ceramic particles and matrix material powder with particle sizes all in the range of 20 μm - 100 μm are mixed according to a ratio to obtain a mixture, which is then loaded into a ball milling tank. Among them, the mass percentage of the input matrix material powder is 70% - 90%, and the mass percentage of the input hard ceramic particle powder is 10% - 30%; grinding balls are added to the ball milling tank, and the grinding balls can be zirconia balls with a diameter of 0.5 mm; a liquid grinding medium such as alcohol is added to the ball milling tank, and the volume ratio of the mixture, grinding balls, and liquid grinding medium can be 1:2:1; grinding, the grinding time can be 12 h - 20 h, and the rotation speed can be 2000 r / min; powder making, a surfactant and an antifoaming agent are added to the composite material slurry obtained by grinding, and after mixing, it is placed in an ultrasonic mixer and mixed for 30 min, and then dried by spray powder making. Among them, the weight of the surfactant is 0.5% - 3% of the weight of the slurry, and the weight of the antifoaming agent is 0.2% - 1% of the weight of the slurry. Among them, the conditions of the spray powder making method are as follows: the atomization pressure is 0.3 - 0.6 MPa, preferably 0.4 - 0.5 MPa; the atomization air flow rate is 0.5 - 5 m 3 / h, preferably 1 - 3 m 3 / h; the inlet temperature is 200 - 600 °C, preferably 300 - 400 °C; the outlet temperature is 50 - 200 °C, preferably 80 - 160 °C.

[0029] Then, a tool blank is prepared through powder metallurgy technology.

[0030] Through a pressing forming process, the matrix material powder and the composite material powder are pressed in a mold to form an initial tool blank. Specifically, a sufficient amount of composite material powder is placed at the position corresponding to the cutting edge 20 in the mold, and a sufficient amount of matrix material powder is placed at the position corresponding to the main body part 10 in the mold. Through the pressing forming process, an initial tool blank is integrally formed under the condition of 200 MPa - 500 MPa. In this case, the part of the initial tool blank corresponding to the cutting edge of the tool is composed of the composite material, and the part of the initial tool blank corresponding to the main body part of the tool is composed of the matrix material, but the present disclosure is not limited thereto. For example, composite material powder can be added at the positions corresponding to both the cutting edge 20 and the main body part 10 in the mold. In this way, the part of the initial tool blank corresponding to the main body part 10 of the tool is composed of the composite material. In other words, the initial tool blank can be integrally formed by the composite material.

[0031] The initial blank of the tool is subjected to solid-phase sintering process in a protective atmosphere. The sintering temperature is generally 0.7 - 1.0 Tm (Tm is the absolute melting point), which can be 910°C - 1500°C, and the sintering time can be 20 min - 40 min, thereby preparing the tool blank. To avoid forming an oxide layer that affects the properties of the tool during sintering, a reducing gas, nitrogen, or an inert gas can be used as the protective gas, or sintering can be performed in a vacuum environment to prevent the powder in the initial blank of the tool from directly contacting with oxidation gases such as oxygen. During the sintering process, since the hard ceramic material has a higher melting point than the matrix material, the hard ceramic particles will always be in a solid state, while the matrix material powder undergoes processes of mutual flow, diffusion, dissolution, and recrystallization. Additionally, along with the processes of mutual flow, diffusion, dissolution, and recrystallization of the matrix material powder, the gas in the powder gaps in the initial blank of the tool or the gas dissolved in the metal can be completely removed at high temperature, increasing the degree of densification.

[0032] Finally, after the tool blank is cooled, it is subjected to conventional grinding and edge sharpening.

[0033] The above method for preparing the tool blank is merely an example. Optionally, the main body 10 made of the matrix material or composite material and the cutting edge 20 made of the composite material can be respectively manufactured by a pressing process or a powder metallurgy process, and then the cutting edge 20 is combined with the main body 10 by welding (for example, cold welding) to manufacture the tool 100.

[0034] Hereinafter, the tool 100 according to the present invention will be described in more detail with reference to embodiments, and the persistent sharpness and blade strength of the tool 100 according to the present invention will be evaluated.

[0035] Example 1

[0036] Composite material slurry is prepared by grinding TiC powder with a particle size of 50 μm and martensitic stainless steel powder with a particle size of 50 μm for 15 h using the above ball milling and mixing process. Among them, the mass percentage of the martensitic stainless steel powder is 80%, and the mass percentage of the TiC powder is 20%.

[0037] Composite material powder is prepared by spray powder method. The conditions of the spray powder method are as follows:

[0038] Atomization pressure: 0.4 MPa, atomization air flow rate: 2 m 3 / h; inlet temperature: 300 - 400°C, outlet temperature: 120°C.

[0039] The composite material powder is integrally pressed by a pressing process to form the initial blank of the tool, and the forming pressure is 300 MPa.

[0040] Sinter the initial blank of the cutting tool in a vacuum environment at a sintering temperature of 1300 °C for 30 minutes to obtain the cutting tool blank.

[0041] After the cutting tool blank is cooled, perform conventional grinding and edge sharpening on it to manufacture the cutting tool 100.

[0042] Example 2

[0043] Manufacture the cutting tool 100 in a method substantially the same as that of Example 1, except that the mass percentage of martensitic stainless steel powder in the composite material powder is 90% and the mass percentage of TiC powder is 10%.

[0044] Example 3

[0045] Manufacture the cutting tool 100 in a method substantially the same as that of Example 1, except that the mass percentage of martensitic stainless steel powder in the composite material powder is 83.3% and the mass percentage of TiC powder is 16.7%.

[0046] Example 4

[0047] Manufacture the cutting tool 100 in a method substantially the same as that of Example 1, except that the mass percentage of martensitic stainless steel powder in the composite material powder is 70% and the mass percentage of TiC powder is 30%.

[0048] Example 5

[0049] Manufacture the cutting tool 100 in a method substantially the same as that of Example 1, except that the mass percentage of martensitic stainless steel powder in the composite material powder is 60% and the mass percentage of TiC powder is 40%.

[0050] Example 6

[0051] Manufacture the cutting tool 100 in a method substantially the same as that of Example 1, except that the mass percentage of martensitic stainless steel powder in the composite material powder is 95% and the mass percentage of TiC powder is 5%.

[0052] Example 7

[0053] Manufacture the cutting tool 100 in a method substantially the same as that of Example 1, except that composite material powder is prepared using TiC powder with a particle size of 10 μm and martensitic stainless steel powder with a particle size of 50 μm.

[0054] Example 8

[0055] Except for preparing the composite powder by using TiC powder with a particle size of 20 μm and martensitic stainless steel powder with a particle size of 50 μm, the cutting tool 100 is manufactured in substantially the same manner as in Example 1.

[0056] Example 9

[0057] Except for preparing the composite powder by using TiC powder with a particle size of 40 μm and martensitic stainless steel powder with a particle size of 50 μm, the cutting tool 100 is manufactured in substantially the same manner as in Example 1.

[0058] Example 10

[0059] Except for preparing the composite powder by using TiC powder with a particle size of 60 μm and martensitic stainless steel powder with a particle size of 50 μm, the cutting tool 100 is manufactured in substantially the same manner as in Example 1.

[0060] Example 11

[0061] Except for preparing the composite powder by using TiC powder with a particle size of 80 μm and martensitic stainless steel powder with a particle size of 50 μm, the cutting tool 100 is manufactured in substantially the same manner as in Example 1.

[0062] Example 12

[0063] Except for preparing the composite powder by using TiC powder with a particle size of 100 μm and martensitic stainless steel powder with a particle size of 50 μm, the cutting tool 100 is manufactured in substantially the same manner as in Example 1.

[0064] Example 13

[0065] Except for preparing the composite powder by using TiC powder with a particle size of 120 μm and martensitic stainless steel powder with a particle size of 50 μm, the cutting tool 100 is manufactured in substantially the same manner as in Example 1.

[0066] Example 14

[0067] Except for preparing the composite powder by using SiC powder with a particle size of 50 μm and martensitic stainless steel powder with a particle size of 50 μm, the cutting tool 100 is manufactured in substantially the same manner as in Example 1.

[0068] Example 15

[0069] Except for preparing the composite powder by using ZrO2 powder with a particle size of 50 μm and martensitic stainless steel powder with a particle size of 50 μm, the cutting tool 100 is manufactured in substantially the same manner as in Example 1.

[0070] Example 16

[0071] Except for preparing the composite powder by using Al2O3 powder with a particle size of 50 μm and martensitic stainless steel powder with a particle size of 50 μm, the tool 100 is manufactured in substantially the same manner as in Example 1.

[0072] Example 17

[0073] Except for preparing the composite powder by using Si3N4 powder with a particle size of 50 μm and martensitic stainless steel powder with a particle size of 50 μm, the tool 100 is manufactured in substantially the same manner as in Example 1.

[0074] Comparative Example 1

[0075] Ordinary martensitic tool.

[0076] The evaluation method is as follows:

[0077] (1) Durability sharpness test: The durability sharpness adopts a simulated tool life test method. The larger the value of the durability sharpness, the longer the durability sharpness life, and vice versa for the smaller value. The specific method is as follows:

[0078] The simulated tool life test method is specifically as follows: The tested tool edge is fixed horizontally downward on the tool fixing device. After adding additional weights, it is pressed on the simulation object with a pressure of 16 N. The cutting simulation object (select 3 mm kraft paper) remains stationary. The tool fixing device is driven by a motor and air pressure to drive the tool to cut in the X-axis direction at a speed of 50 mm / s reciprocating motion. At the same time, it rises in the Z-axis direction and displaces 1 mm in the Y-axis direction to form the simulation object. The cutting stroke is 100 mm. After cutting the simulation object 5 times, it ends. The durability sharpness of the tool is judged by using the evaluation object (ham sausage). The test is terminated until the evaluation object cannot be cut. Record the total number of cuts from the start to the end of the test, which is the durability sharpness of the tool. The more the total number of cuts, the higher the durability sharpness.

[0079] (2) Blade strength test: Test the impact toughness of the blade. The reference standard is GBT 1817-1995. Specifically, by placing a pendulum with a certain mass at a certain height and allowing the pendulum to swing freely downward, observe the mass of the pendulum and the height of the pendulum when the test object cracks. Through the calculation formula obtained in the standard, the impact toughness value is obtained. The larger the impact toughness value, the stronger the toughness resistance and the higher the strength of the material. Generally speaking, it is less likely to chip.

[0080] By using the above evaluation method, the durability sharpness and blade strength of the tools in Examples 1 to 17 and Comparative Example 1 were tested, and the test results are shown in Table 1 below.

[0081] Table 1

[0082] Serial number Permanent sharpness <![CDATA[Blade strength (J / cm 3 )]]> Example 1 800 47 Example 2 620 51 Example 3 690 50 Example 4 840 45 Example 5 860 29 Example 6 420 53 Example 7 570 50 Example 8 680 49 Example 9 760 48 Example 10 810 44 Example 11 780 41 Example 12 650 40 Example 13 490 37 Example 14 810 46 Example 15 800 47 Example 16 780 48 Example 17 800 47 Comparative Example 1 380 55

[0083] As can be seen from Table 1, the cutting tools of Examples 1 to 13 all exhibited good long-term sharpness.

[0084] Comparing the test results of the cutting tools of Example 1 and Example 5, it was found that although the long-term sharpness of Example 5 had a small increase, the strength of its blade decreased significantly due to the too high mass percentage of hard ceramic particles. Generally, the impact toughness of the blade is required to be not less than 40 J / cm 3 . Combining with Example 4, it can be known that the mass percentage of hard ceramic particles is preferably not more than 30%. Combining with Comparative Example 1 and comparing the test results of the cutting tools of Example 1 and Example 6, it was found that the long-term sharpness of Example 6 increased less due to the too low mass percentage of hard ceramic particles it contained. Combining with Example 2, it can be known that the mass percentage of hard ceramic particles is preferably not less than 10% to significantly improve the long-term sharpness of the cutting tool. That is to say, when the mass percentage of hard ceramic particles is in the range of 10%-30%, it has excellent long-term sharpness and blade strength performance.

[0085] Comparing the test results of the cutting tools of Examples 1 to 6, it was found that the higher the mass percentage of hard ceramic particles, the stronger the improvement effect on the long-term sharpness of the cutting tool 100, which confirmed that the hard ceramic particles of the inventive concept can significantly improve the long-term sharpness performance of the cutting tool.

[0086] Comparing the test results of Comparative Example 1 and the cutting tool of Example 7, it was found that the micro-serrated structure generated by Example 7 with too small particle size (less than 20 μm) of its hard ceramic particles had a small improvement on its long-term sharpness. It was confirmed that the particle size of the hard ceramic particles is preferably greater than 20 μm to significantly enhance the long-term sharpness of the cutting edge 20.

[0087] Comparing the test results of Comparative Example 1 and the cutting tool of Example 13, it was found that the long-term sharpness of Example 13 was not improved well, and its blade strength was reduced significantly, which confirmed that although the particle size of the hard ceramic particles greater than 100 μm can still improve the long-term sharpness to a certain extent, but due to its too large particle size, the blade strength decreased significantly.

[0088] Compare the test results of the cutting tools of Examples 8 to 12 in combination with Comparative Example 1. It can be found from Table 1 that as the particle size of the hard ceramic particles increases, the sharpness durability of the cutting tool shows a trend of first increasing and then decreasing, but all have good lasting sharpness (for example, the lasting sharpness is greater than 600), and still have excellent blade strength (for example, greater than 40 J / cm 3 ).

[0089] Compare the test results of the cutting tools of Examples 14 to 17 in combination with Comparative Example 1. The change in the type of hard ceramic material has a slight impact on the lasting sharpness of the cutting tool, and all have a lasting sharpness superior to that of the cutting tool in Comparative Example 1.

[0090] Although the present invention has been specifically shown and described with reference to exemplary embodiments of the present invention, those of ordinary skill in the art will understand that various changes in form and detail may be made herein without departing from the spirit and scope of the present invention as defined by the claims and their equivalents. The embodiments should be considered only in a descriptive sense and not for purposes of limitation. Therefore, the scope of the present invention is not defined by the specific embodiments of the present invention, but by the claims, and all differences within the scope will be construed as being included in the present invention.

Claims

1. A method for manufacturing a cutting tool, characterized in that, The method includes: Manufacturing a composite material slurry by uniformly mixing matrix material powder and hard ceramic particles through a ball milling mixing process, and preparing dry composite material powder by a spray powder making method, wherein the matrix material includes at least one of martensitic stainless steel, austenitic stainless steel, and duplex stainless steel, the hard ceramic particles have a melting point higher than that of the matrix material and include at least one of tungsten carbide, silicon carbide, zirconia, alumina, chromium carbide, titanium oxide, titanium carbide, and silicon nitride, wherein the mass percentage of the matrix material powder in the composite material powder is 70% - 90%, and the mass percentage of the hard ceramic particles is 10% - 30%; Pressing the composite material powder in a mold to form an initial tool blank, wherein the part of the initial tool blank corresponding to the cutting edge of the tool is made of the composite material, and the part of the initial tool blank corresponding to the main body part of the tool is made of the composite material; Performing solid-phase sintering on the initial tool blank in a protective atmosphere so that the matrix material melts and the hard ceramic particles remain in a particulate state to obtain a tool blank; and Grinding and sharpening the tool blank after cooling.

2. The method according to claim 1, wherein The particle sizes of both the matrix material powder and the hard ceramic particles are in the range of 20 μm - 100 μm.

3. The method according to claim 1, wherein The forming pressure when pressing to form the tool blank is 200 MPa - 500 MPa.

4. The method according to claim 1, wherein In the sintering step, the sintering temperature is 910°C - 1500°C, and the sintering time is 20 min - 40 min.

5. The method according to claim 1, characterized in that, The tool has a lasting sharpness greater than 600 and a blade strength greater than or equal to 40 J / cm 3 ².

6. The method according to claim 1, wherein The cutting edge of the tool has a micro-serrated structure.

7. The method according to claim 1, characterized in that, In the sintering step, the sintering temperature is 0.7Tm to 1.0Tm, where Tm is the absolute melting point.

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