A cemented carbide tool material for machining superalloys and a method of making the same

Abstract

The application provides a hard alloy cutter material for high-temperature alloy machining and a preparation method thereof, and belongs to the technical field of hard alloy cutter preparation. The application adopts a cobalt component gradient idea to adjust the hardness of each layer structure, obtains a more wear-resistant high-temperature structure, and low cobalt components can inhibit the mechanical machining sticking of a high-temperature alloy workpiece, realize high-precision and high-efficiency machining, the spraying slurry can improve the interfacial bonding strength between gradient layers, reduce the interfacial stress, and ensure the comprehensive performance of the cutter. The gradient structure is designed to be axisymmetric, which can significantly reduce the internal stress of the structure, improve the performance, increase the usable area of the cutter, and prolong the service life of the cutter. The results of the embodiments show that the hard alloy cutter material has a gradient structure, the fracture toughness is greater than or equal to 12 MPa.m 1 / 2 , the microhardness is greater than or equal to 20.1 GPa, the bending strength is greater than or equal to 3530 MPa, and the high-temperature (1000 DEG C) hardness is greater than or equal to 16.8 GPa.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cemented carbide tool preparation, and particularly relates to a cemented carbide tool material for high-temperature alloy machining and a preparation method thereof. BACKGROUND

[0002] The high-temperature alloy has excellent high-temperature strength, high-temperature corrosion resistance, fatigue resistance and fracture toughness, and is widely used in the fields of aerospace and energy. Since the main component elements of the high-temperature alloy are cobalt and nickel, the cobalt in the high-temperature alloy is easy to react with the cobalt in the cemented carbide tool during machining, resulting in tool sticking, which seriously affects the machining precision and efficiency.

[0003] Therefore, how to overcome the tool sticking problem during machining of the high-temperature alloy workpiece and improve the high-temperature performance of the tool has become a technical problem to be solved in the field. SUMMARY

[0004] The present application aims to provide a cemented carbide tool material for high-temperature alloy machining and a preparation method thereof. The cemented carbide tool material for high-temperature alloy machining prepared by the preparation method has excellent high-red hardness and anti-sticking performance.

[0005] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions:

[0006] The present application provides a preparation method of a cemented carbide tool material for high-temperature alloy machining, comprising the following steps:

[0007] (1) mixing tungsten carbide powder, cobalt powder, vanadium carbide and tantalum carbide powder to obtain n groups of mixed powders;

[0008] The n groups of mixed powders comprise, in terms of 100% of the mass percentage of each group of mixed powders: 93-99.1% of tungsten carbide powder, 0.5-6% of cobalt powder, 0.2-0.5% of vanadium carbide and 0.2-0.5% of tantalum carbide powder;

[0009] The cobalt content in the n groups of mixed powders changes in a gradient that first increases and then decreases; the gradient difference of the gradient change of the cobalt content is 0.8-1%;

[0010] (2) cold pressing the n groups of mixed powders obtained in the step (1) to obtain n groups of green bodies;

[0011] (3) stacking and arranging the n groups of green bodies obtained in the step (2) according to the gradient change of the cobalt content that first increases and then decreases, and then spraying slurry between the adjacent two groups of green bodies to obtain a gradient green body;

[0012] (4) sintering the gradient green body obtained in the step (3) to obtain a cemented carbide tool material for high-temperature alloy machining.

[0013] Preferably, the average particle size of the tungsten carbide powder, cobalt powder, vanadium carbide powder and tantalum carbide powder in step (1) is independently 0.2-0.4 μm.

[0014] Preferably, the mass percentage of the cobalt powder in the mixed powder with the lowest cobalt content in the n groups of mixed powders obtained in step (1) is ≤1.5%.

[0015] Preferably, the pressure of the cold-pressing in step (2) is independently 105-130 MPa.

[0016] Preferably, the thickness of the n groups of green bodies in step (2) is independently 6-9 mm.

[0017] Preferably, the raw material of the slurry in step (3) comprises a PVA plasticizer solution and mixed powder, the PVA plasticizer solution comprises 10 wt.% PVA plasticizer and 90 wt.% water, and the mixed powder comprises the average of the components of the mixed powder in the two adjacent groups of green bodies.

[0018] Preferably, the mass ratio of the mixed powder to the PVA plasticizer is 1:(1.5-1.7).

[0019] Preferably, the thickness of the slurry in step (3) is 0.1-0.3 mm.

[0020] Preferably, the sintering method in step (4) is spark plasma sintering, the sintering temperature is 1060-1120℃, and the holding time of the sintering is 3-5 min.

[0021] The present application provides a hard alloy tool material for high-temperature alloy machining prepared by the preparation method described in the above technical solution, and the hard alloy tool material for high-temperature alloy machining has a gradient structure.

[0022] The application provides a preparation method of a hard alloy tool material for high-temperature alloy machining, comprising the following steps: (1) mixing tungsten carbide powder, cobalt powder, vanadium carbide and tantalum carbide powder to obtain n groups of mixed powder; in terms of 100% of the mass percentage of each group of mixed powder, the mixed powder comprises 93-99.1% of tungsten carbide powder, 0.5-6% of cobalt powder, 0.2-0.5% of vanadium carbide and 0.2-0.5% of tantalum carbide powder; the cobalt content in the n groups of mixed powder changes in a gradient that first increases and then decreases; the gradient difference of the cobalt content in the gradient change is 0.8-1%; (2) cold pressing the n groups of mixed powder obtained in the step (1) to obtain n groups of blanks; (3) stacking the n groups of blanks obtained in the step (2) according to the gradient change of the cobalt content that first increases and then decreases, and then spraying slurry between the adjacent two groups of blanks to obtain a gradient blank; and (4) sintering the gradient blank obtained in the step (3) to obtain the hard alloy tool material for high-temperature alloy machining. The application adopts the cobalt component gradient idea to adjust the hardness of each layer structure, obtains a more wear-resistant high-temperature structure, and the low cobalt component can inhibit the tool sticking of the high-temperature alloy workpiece during machining, so that high-precision and high-efficiency machining is realized; the gradient layer spraying slurry can improve the interlayer bonding strength and reduce the interface stress, so as to ensure the comprehensive performance of the hard alloy tool; and the design of the gradient structure into an axisymmetric structure can significantly reduce the internal stress of the structure, improve the performance, increase the usable area of the tool and prolong the service life of the tool. The results of the embodiments show that the hard alloy tool material prepared by the preparation method has a gradient structure, the fracture toughness of the hard alloy tool material is greater than or equal to 12 MPa·m 1 / 2 , the microhardness is greater than or equal to 20.1 GPa, the bending strength is greater than or equal to 3530 MPa, and the high-temperature (1000 DEG C) hardness is greater than or equal to 16.8 GPa. DETAILED DESCRIPTION

[0023] The application provides a preparation method of a hard alloy tool material for high-temperature alloy machining, comprising the following steps:

[0024] (1) mixing tungsten carbide powder, cobalt powder, vanadium carbide and tantalum carbide powder to obtain n groups of mixed powder;

[0025] in terms of 100% of the mass percentage of each group of mixed powder, the mixed powder comprises 93-99.1% of tungsten carbide powder, 0.5-6% of cobalt powder, 0.2-0.5% of vanadium carbide and 0.2-0.5% of tantalum carbide powder;

[0026] the cobalt content in the n groups of mixed powder changes in a gradient that first increases and then decreases; the gradient difference of the cobalt content in the gradient change is 0.8-1%;

[0027] (2) cold pressing the n groups of mixed powder obtained in the step (1) to obtain n groups of blanks;

[0028] (3) sequentially layering the n groups of green bodies obtained in step (2) according to the gradient variation of the cobalt content from increasing to decreasing, and then spraying slurry between the adjacent two groups of green bodies to obtain gradient green bodies;

[0029] (4) sintering the gradient green bodies obtained in step (4) to form a hard alloy tool material for machining high-temperature alloy.

[0030] In the present application, the tungsten carbide powder, cobalt powder, vanadium carbide and tantalum carbide powder are mixed to obtain n groups of mixed powders.

[0031] In the present application, the tungsten carbide powder, cobalt powder, vanadium carbide and tantalum carbide powder are mixed to obtain n groups of mixed powders.

[0032] In the present application, the n is preferably a natural number ≥3, more preferably 5, 7 or 9.

[0033] In the present application, the gradient difference of the cobalt content gradient variation is 0.8-1%, preferably 0.9-1%. In the present application, the mass percentage of the cobalt powder in the mixed powder with the lowest cobalt content in the n groups of mixed powders is preferably ≤1.5%. The present application adopts the cobalt component gradient idea to adjust the hardness of each layer structure, and obtains a more wear-resistant high-temperature structure, and the low cobalt component can inhibit the mechanical machining tool sticking of the high-temperature alloy workpiece, and realizes high-precision and high-efficiency machining.

[0034] The present application does not have special limitations on the mixing method, and each component can be mixed uniformly.

[0035] After obtaining the n groups of mixed powders, the present application respectively cold-presses the n groups of mixed powders to form n groups of green bodies.

[0036] In the present application, the pressure of the cold-pressing is independently preferably 105-130 MPa, more preferably 110-125 MPa, and further preferably 115-120 MPa.

[0037] In the present application, the thickness of each group of green bodies is preferably independently 6-9 mm, more preferably 7-8 mm. The present application facilitates obtaining the desired thickness of the hard alloy tool material for high-temperature alloy machining by controlling the thickness of the green bodies.

[0038] After obtaining the n groups of green bodies, the present application arranges the n groups of green bodies in turn in a gradient change of increasing and then decreasing cobalt content, and then sprays the slurry between the adjacent two groups of green bodies to obtain a gradient green body.

[0039] In the present application, when n is 5, 7 or 9, the green body with the highest cobalt content is used as the middle layer, and the compositions of the green bodies at the symmetrical positions on both sides are preferably the same.

[0040] In the present application, the raw material of the slurry preferably includes a PVA plasticizer solution and a mixed powder; the PVA plasticizer solution preferably includes 10 wt.% of PVA plasticizer and 90 wt.% of water; and the composition of the mixed powder is preferably the average of the compositions of the mixed powders in the adjacent two groups of green bodies. In the present application, the mass ratio of the mixed powder to the PVA plasticizer is preferably 1:(1.5-1.7), more preferably 1:(1.5-1.6).

[0041] In the present application, the thickness of each layer of the slurry is preferably 0.1-0.3 mm, more preferably 0.15-0.25 mm, and further preferably 0.20 mm.

[0042] After obtaining the gradient green body, the present application sinter-forms the gradient green body to obtain the hard alloy tool material for high-temperature alloy machining.

[0043] In the present application, the sinter-forming method is preferably spark plasma sintering; the sinter-forming temperature is preferably 1060-1120℃, more preferably 1080-1100℃; and the sinter-forming holding time is preferably 3-5 min, more preferably 4-5 min. The present application can further improve the performance of the material by controlling the parameters of sinter-forming.

[0044] The present application adopts the cobalt component gradient idea to adjust the hardness of each layer structure, obtains a more wear-resistant high-temperature structure, and at the same time, the low cobalt component can inhibit the mechanical processing sticking of the high-temperature alloy workpiece, realizes high-precision and high-efficiency processing thereof; the gradient layer interlayer sprayed slurry can improve the interlayer bonding strength and reduce the interface stress, and ensure the comprehensive performance of the hard alloy tool; and the gradient structure design into an axisymmetric structure can significantly reduce the internal stress of the structure, improve the performance, on the other hand, increase the usable area of the tool, and prolong the service life of the tool.

[0045] The present application is used for solving the problem of easy sticking of high-temperature alloy to the common cemented carbide cutter in the process of preparing the cemented carbide material, by adding grain inhibitor, gradient structure design and sintering treatment, and strictly controlling the parameters in the powder component ratio, cold-pressing forming process, slurry preparation process, spraying process and sintering process, the relationship between the hardness and high-temperature mechanical properties of the cemented carbide is adjusted, so that the high hardness and high-temperature mechanical properties are maintained, the component control precision is high, the process stability and repeatability are strong, and the anti-sticking and high-temperature resistance of the cemented carbide cutter are improved.

[0046] The present application provides the cemented carbide cutter material for high-temperature alloy machining prepared by the preparation method.

[0047] The cemented carbide cutter material provided by the present application has a gradient structure, the fracture toughness of the cemented carbide cutter material is greater than or equal to 12 MPa·m 1 / 2 , the microhardness is greater than or equal to 20.1 GPa, the bending strength is greater than or equal to 3530 MPa, and the high-temperature (1000 DEG C) hardness is greater than or equal to 16.8 GPa.

[0048] The technical solutions in the present application will be clearly and completely described below in combination with the embodiments in the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0049] Embodiment 1

[0050] A preparation method of a cemented carbide cutter material for high-temperature alloy machining comprises the following steps:

[0051] (1) mixing tungsten carbide powder, cobalt powder, vanadium carbide and tantalum carbide powder to obtain seven groups of mixed powder;

[0052] The cobalt content of the seven groups of mixed powders changes in a gradient of first increasing and then decreasing, and the components of the seven groups of mixed powders are as follows, with the mass percentage of each group of mixed powders being 100%: the first group of mixed powders: tungsten carbide powder 99.1%, cobalt powder 0.5%, vanadium carbide 0.2%, and tantalum carbide powder 0.2%; the second group of mixed powders: tungsten carbide powder 97.9%, cobalt powder 1.3%, vanadium carbide 0.3%, and tantalum carbide powder 0.5%; the third group of mixed powders: tungsten carbide powder 96.9%, cobalt powder 2.1%, vanadium carbide 0.5%, and tantalum carbide powder 0.5%; the fourth group of mixed powders: tungsten carbide powder 96.2%, cobalt powder 2.9%, vanadium carbide 0.4%, and tantalum carbide powder 0.5%; the fifth group of mixed powders: tungsten carbide powder 96.9%, cobalt powder 2.1%, vanadium carbide 0.5%, and tantalum carbide powder 0.5%; the sixth group of mixed powders: tungsten carbide powder 97.9%, cobalt powder 1.3%, vanadium carbide 0.3%, and tantalum carbide powder 0.5%; and the seventh group of mixed powders: tungsten carbide powder 99.1%, cobalt powder 0.5%, vanadium carbide 0.2%, and tantalum carbide powder 0.2%; the average particle size of the tungsten carbide powder, cobalt powder, vanadium carbide, and tantalum carbide powder is 0.2 μm, and the purity is ≥99.5%;

[0053] (2) The seven groups of mixed powders obtained in step (1) are respectively cold-pressed to form seven groups of green bodies; the pressure of the cold-pressing is 130 MPa; and the thickness of the seven groups of green bodies is independently 7 mm;

[0054] (3) The seven groups of green bodies obtained in step (2) are sequentially stacked in a gradient of first increasing and then decreasing of the cobalt content, and then a slurry is sprayed between the adjacent two groups of green bodies to obtain a gradient green body; the raw material of the slurry is a PVA plasticizer solution and a mixed powder; the PVA plasticizer solution is 10 wt.% PVA plasticizer and 90 wt.% water; the component of the mixed powder is the average value of the components of the mixed powders in the adjacent two groups of green bodies of the slurry; the mass ratio of the mixed powder to the PVA plasticizer is 1:1.5; and the thickness of the slurry is 0.15 mm;

[0055] (4) The gradient green body obtained in step (4) is sintered by a spark plasma sintering method to form a high-temperature alloy processing hard alloy tool material; the sintering temperature is 1060°C, and the holding time of the sintering is 3 min.

[0056] Example 2

[0057] A preparation method of a high-temperature alloy processing hard alloy tool material is the following steps:

[0058] (1) Tungsten carbide powder, cobalt powder, vanadium carbide, and tantalum carbide powder are mixed to obtain seven groups of mixed powders;

[0059] The cobalt content of the seven groups of mixed powders increases first and then decreases in a gradient, and the components of the seven groups of mixed powders are as follows, with the mass percentage of each group of mixed powders being 100%: the first group of mixed powders: tungsten carbide powder 98.7%, cobalt powder 0.7%, vanadium carbide 0.3%, and tantalum carbide powder 0.3%; the second group of mixed powders: tungsten carbide powder 97.5%, cobalt powder 1.6%, vanadium carbide 0.4%, and tantalum carbide powder 0.5%; the third group of mixed powders: tungsten carbide powder 96.5%, cobalt powder 2.5%, vanadium carbide 0.5%, and tantalum carbide powder 0.5%; the fourth group of mixed powders: tungsten carbide powder 95.8%, cobalt powder 3.4%, vanadium carbide 0.4%, and tantalum carbide powder 0.4%; the fifth group of mixed powders: tungsten carbide powder 96.5%, cobalt powder 2.5%, vanadium carbide 0.5%, and tantalum carbide powder 0.5%; the sixth group of mixed powders: tungsten carbide powder 97.5%, cobalt powder 1.6%, vanadium carbide 0.4%, and tantalum carbide powder 0.5%; the seventh group of mixed powders: tungsten carbide powder 98.7%, cobalt powder 0.7%, vanadium carbide 0.3%, and tantalum carbide powder 0.3%; the average particle size of the tungsten carbide powder, cobalt powder, vanadium carbide, and tantalum carbide powder is 0.4 μm, and the purity is ≥99.5%;

[0060] (2) The seven groups of mixed powders obtained in step (1) are respectively cold-pressed to form seven groups of green bodies; the pressure of the cold-pressing is 130 MPa; and the thickness of the seven groups of green bodies is independently 8 mm;

[0061] (3) The seven groups of green bodies obtained in step (2) are sequentially stacked according to the gradient change of the cobalt content increasing first and then decreasing, and then a slurry is sprayed between the adjacent two groups of green bodies to obtain a gradient green body; the raw material of the slurry is a PVA plasticizer solution and a mixed powder; the PVA plasticizer solution is 10 wt.% PVA plasticizer and 90 wt.% water; the components of the mixed powder are the average value of the components of the mixed powders in the adjacent two groups of green bodies of the slurry; the mass ratio of the mixed powder to the PVA plasticizer is 1:1.7; and the thickness of the slurry is 0.3 mm;

[0062] (4) The gradient green body obtained in step (4) is sintered by a spark plasma sintering method to form a high-temperature alloy processing hard alloy tool material; the sintering temperature is 1120°C, and the holding time of the sintering is 5 min.

[0063] Example 3

[0064] A preparation method of a high-temperature alloy processing hard alloy tool material is the following steps:

[0065] (1) Tungsten carbide powder, cobalt powder, vanadium carbide, and tantalum carbide powder are mixed to obtain nine groups of mixed powders;

[0066] The cobalt content of the nine groups of mixed powders increases first and then decreases in gradient, and the components of the nine groups of mixed powders are as follows, with the mass percentage of each group of mixed powder being 100%: the first group of mixed powder: tungsten carbide powder 98.6%, cobalt powder 0.8%, vanadium carbide 0.3%, and tantalum carbide powder 0.3%; the second group of mixed powder: tungsten carbide powder 97.4%, cobalt powder 1.7%, vanadium carbide 0.4%, and tantalum carbide powder 0.5%; the third group of mixed powder: tungsten carbide powder 96.4%, cobalt powder 2.6%, vanadium carbide 0.5%, and tantalum carbide powder 0.5%; the fourth group of mixed powder: tungsten carbide powder 95.7%, cobalt powder 3.5%, vanadium carbide 0.4%, and tantalum carbide powder 0.4%; the fifth group of mixed powder: tungsten carbide powder 94.9%, cobalt powder 4.3%, vanadium carbide 0.4%, and tantalum carbide powder 0.4%; the sixth group of mixed powder: tungsten carbide powder 95.7%, cobalt powder 3.5%, vanadium carbide 0.4%, and tantalum carbide powder 0.4%; the seventh group of mixed powder: tungsten carbide powder 96.4%, cobalt powder 2.6%, vanadium carbide 0.5%, and tantalum carbide powder 0.5%; the eighth group of mixed powder: tungsten carbide powder 97.4%, cobalt powder 1.7%, vanadium carbide 0.4%, and tantalum carbide powder 0.5%; the ninth group of mixed powder: tungsten carbide powder 98.6%, cobalt powder 0.8%, vanadium carbide 0.3%, and tantalum carbide powder 0.3%; the average particle size of the tungsten carbide powder, cobalt powder, vanadium carbide, and tantalum carbide powder is 0.4 μm, and the purity is ≥99.5%;

[0067] (2) The nine groups of mixed powders obtained in step (1) are respectively cold-pressed to obtain nine groups of green bodies; the pressure of the cold-pressing is 120 MPa; and the thickness of the nine groups of green bodies is independently 9 mm;

[0068] (3) The nine groups of green bodies obtained in step (2) are sequentially stacked according to the cobalt content increasing first and then decreasing in gradient, and then a slurry is sprayed between adjacent two groups of green bodies to obtain a gradient green body; the raw material of the slurry is a PVA plasticizer solution and a mixed powder; the PVA plasticizer solution is 10 wt.% PVA plasticizer and 90 wt.% water; the components of the mixed powder are the average value of the components of the mixed powder in the adjacent two groups of green bodies of the slurry; the mass ratio of the mixed powder to the PVA plasticizer is 1:1.7; and the thickness of the slurry is 0.2 mm;

[0069] (4) The gradient green body obtained in step (4) is sintered by spark plasma sintering to obtain a hard alloy tool material for high-temperature alloy machining; the sintering temperature is 1120 °C, and the holding time of the sintering is 4 min.

[0070] Example 4

[0071] A preparation method of a hard alloy tool material for high-temperature alloy machining is the following steps:

[0072] (1) mixing tungsten carbide powder, cobalt powder, vanadium carbide powder and tantalum carbide powder to obtain five groups of mixed powders;

[0073] The cobalt content in the five groups of mixed powders changes in a gradient manner of first increasing and then decreasing, and the components of the five groups of mixed powders are as follows, with the mass percentage of each group of mixed powders being 100%: the first group of mixed powders: tungsten carbide powder 97.9%, cobalt powder 1.3%, vanadium carbide powder 0.5% and tantalum carbide powder 0.3%; the second group of mixed powders: tungsten carbide powder 96.7%, cobalt powder 2.3%, vanadium carbide powder 0.5% and tantalum carbide powder 0.5%; the third group of mixed powders: tungsten carbide powder 95.8%, cobalt powder 3.3%, vanadium carbide powder 0.4% and tantalum carbide powder 0.5%; the fourth group of mixed powders: tungsten carbide powder 96.7%, cobalt powder 2.3%, vanadium carbide powder 0.5% and tantalum carbide powder 0.5%; the fifth group of mixed powders: tungsten carbide powder 97.9%, cobalt powder 1.3%, vanadium carbide powder 0.5% and tantalum carbide powder 0.3%; the average particle size of the tungsten carbide powder, cobalt powder, vanadium carbide powder and tantalum carbide powder is 0.2 μm, and the purity is ≥99.5%;

[0074] (2) cold-pressing the five groups of mixed powders obtained in step (1) to obtain five groups of green bodies; the pressure of the cold-pressing is 125 MPa; the thickness of the five groups of green bodies is independently 7 mm;

[0075] (3) stacking the five groups of green bodies obtained in step (2) in a gradient manner of first increasing and then decreasing of the cobalt content, and then spraying slurry between the adjacent two groups of green bodies to obtain a gradient green body; the raw material of the slurry is PVA plasticizer solution and mixed powder; the PVA plasticizer solution is 10 wt.% PVA plasticizer and 90 wt.% water; the component of the mixed powder is the average value of the components of the mixed powders in the adjacent two groups of green bodies of the slurry; the mass ratio of the mixed powder to PVA plasticizer is 1:1.6; the thickness of the slurry is 0.3 mm;

[0076] (4) sintering the gradient green body obtained in step (4) by spark plasma sintering to obtain a hard alloy tool material for high-temperature alloy machining; the sintering temperature is 1120°C, and the holding time of the sintering is 3 min.

[0077] The properties of the hard alloy tool materials for high-temperature alloy machining prepared in Examples 1-4 were tested, and the results are shown in Table 1:

[0078] Table 1 Properties of the hard alloy tool materials for high-temperature alloy machining prepared in Examples 1-4

[0079]

[0080] As shown in Table 1, the hard alloy cutter material prepared by the preparation method provided by the application has a gradient structure, the fracture toughness of the hard alloy cutter material is greater than or equal to 12 MPa·m 1 / 2 , the microhardness is greater than or equal to 20.1 GPa, the bending strength is greater than or equal to 3530 MPa, the high-temperature (1000℃) hardness is greater than or equal to 16.8 GPa, and the hard alloy cutter material has excellent high red hardness and anti-stick performance.

[0081] The above only describes the preferred embodiments of the application, and it should be noted that those skilled in the art can make several improvements and refinements without departing from the principles of the application, and these improvements and refinements should also be considered as the protection scope of the application.

Claims

1. A method for preparing a cemented carbide tool material for high-temperature alloy machining, comprising the following steps: (1) mixing tungsten carbide powder, cobalt powder, vanadium carbide powder and tantalum carbide powder to obtain n groups of mixed powders; in terms of 100% by mass of each group of mixed powders, comprising: 93-99.1% tungsten carbide powder, 0.5-6% cobalt powder, 0.2-0.5% vanadium carbide powder and 0.2-0.5% tantalum carbide powder; the cobalt content in the n groups of mixed powders changes in a gradient that first increases and then decreases; the gradient difference of the cobalt content in the gradient change is 0.8-1%; n is a natural number greater than or equal to 3; (2) separately cold-pressing the n groups of mixed powders obtained in step (1) to obtain n groups of green bodies; (3) stacking the n groups of green bodies obtained in step (2) in turn according to a gradient that first increases and then decreases in cobalt content, and then spraying a slurry between the adjacent two groups of green bodies to obtain a gradient green body; (4) sintering the gradient green body obtained in step (3) to obtain a cemented carbide tool material for high-temperature alloy machining; the raw materials of the slurry in step (3) comprise a PVA plasticizer solution and a mixed powder, the PVA plasticizer solution comprises 10 wt.% PVA plasticizer and 90 wt.% water, and the mixed powder has a composition that is the average of the compositions of the mixed powders in the adjacent two groups of green bodies in the slurry; the mass ratio of the mixed powder to the PVA plasticizer is 1: (1.5-1.7) ; the thickness of each layer of slurry in step (3) is 0.1-0.3 mm; the sintering method in step (4) is spark plasma sintering, the sintering temperature is 1060-1120℃, and the sintering holding time is 3-5 min.

2. The production method according to claim 1, characterized by, the average particle size of the tungsten carbide powder, cobalt powder, vanadium carbide powder and tantalum carbide powder in step (1) is independently 0.2-0.4 μm.

3. The preparation method according to claim 1, characterized in that, the mass percentage of cobalt powder in the mixed powder with the lowest cobalt content among the n groups of mixed powders obtained in step (1) is ≤1.5%.

4. The method of claim 1, wherein, the pressure of cold-pressing in step (2) is independently 105-130 MPa.

5. The preparation method according to claim 1, characterized in that, the thickness of each group of green bodies in step (2) is independently 6-9 mm.

6. The cemented carbide tool material for high-temperature alloy machining prepared by the method of any one of claims 1-5, wherein the cemented carbide tool material for high-temperature alloy machining has a gradient structure.

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