Double flat wedge-shaped splitting cutter bar and preparation method thereof

Abstract

The invention discloses a double flat position wedge-shaped splitting knife bar and a preparation method thereof, belonging to the field of wire bonding splitting knives, and the steps of the method are: spheroidizing tungsten carbide powder with a plasma flame to obtain tungsten carbide spherical micropowder; plating a nickel shell layer on the surface of the tungsten carbide spherical micropowder to obtain surface-modified tungsten carbide micropowder; using the surface-modified tungsten carbide micropowder as a raw material, the double flat position wedge-shaped splitting knife bar is printed out by SLM technology. The flat position and center hole of the obtained bar are of high precision, and there will be no problems of hole blocking and perforation steps. The bar has high density, high hardness and bending strength, which is conducive to positioning during further processing, and is conducive to subsequent precision processing of the splitting knife head, and has a favorable effect on improving the wear resistance of the splitting knife and extending its service life.

Description

Technical Field

[0001] The invention relates to a double-flat wedge-shaped splitting tool bar and a preparation method thereof, and belongs to the field of wire bonding splitting tools. Background Art

[0002] The wedge-shaped splitter is one of the important tools for wire bonding, with the characteristics of small welding size, high welding density, and the ability to weld deep cavity devices. The main body of the splitter is usually cylindrical, with an opening parallel to the main body axis, which is used to pass through the bonding wire. The opening diameter is related to the wire diameter of the wire used; the main body of the splitter is provided with a flat position, which is used to be clamped by the fixture during work; the blade head is wedge-shaped, and the end face of the blade head has various structures according to the use requirements. The end face of the blade head determines the size and morphology of the solder joint.

[0003] The bonding area size requirements of the wedge-shaped splitter head are strict, and the accuracy is generally controlled within 0.01μm. In order to ensure the processing accuracy of the cutter head, the flat position and center hole accuracy of the splitter bar should be improved as much as possible to facilitate accurate positioning during the processing of the cutter head.

[0004] At present, the production process of splitter bar material is powder mixing-pressing and sintering-blank rounding-grinding by grinder-center drilling. This process is difficult to produce high-precision center holes. In the drilling process, if single-through hole processing is used, the processing time is long, the electrode loss is large, and the hole is prone to blockage; if the through-hole processing is used, the through-hole step may appear, which is not conducive to the threading of the splitter. Summary of the invention

[0005] In order to overcome the deficiencies of the prior art, the present invention provides a double-flat position wedge-shaped splitting cutter bar stock and a preparation method thereof, which has a high-precision flat position and a center hole.

[0006] The technical solution adopted by the present invention to solve its technical problem is:

[0007] In a first aspect, the present application provides a method for preparing a double flat wedge-shaped splitting cutter bar, comprising the following steps:

[0008] The tungsten carbide powder is spheroidized by plasma flame to obtain spherical tungsten carbide powder;

[0009] Plating a nickel shell layer on the surface of the tungsten carbide spherical micropowder to obtain surface-modified tungsten carbide micropowder;

[0010] The surface modified tungsten carbide powder is used as a raw material, and the double flat position wedge-shaped splitting tool rod is printed by SLM technology; the double flat position wedge-shaped splitting tool rod comprises a quasi-cylinder, the quasi-cylinder is provided with a center hole penetrating along its own axial direction, and the surface of the quasi-cylinder is provided with a first flat position and a second flat position parallel to each other, the first flat position is equal to the length of the quasi-cylinder, and the second flat position extends from one end of the quasi-cylinder to the middle.

[0011] The method for preparing a double-flat wedge-shaped riving cutter bar provided in the present application can produce a double-flat wedge-shaped riving cutter bar with a high-precision flat position and a high-precision center hole. The bar has high density, high hardness and bending strength, which is conducive to positioning during further processing and subsequent precision processing of the riving cutter head, and has a favorable effect on improving the wear resistance of the riving cutter and extending its service life.

[0012] Furthermore, the step of spheroidizing the tungsten carbide powder with a plasma flame to obtain spherical tungsten carbide powder comprises:

[0013] The reactor was evacuated to a back-end vacuum of 0.5 Pa, and a mixture of Ar and H2 was introduced as the outer plasma gas source, and the reactor was arced to generate a plasma flame;

[0014] Ar is introduced as a carrier gas to feed the tungsten carbide powder into the reactor so that the melted tungsten carbide powder is cooled and spheroidized under the action of the circulating Ar quenching gas, and the spherical tungsten carbide powder deposited at the bottom of the reactor is collected.

[0015] Furthermore, in the step of introducing a mixed gas of Ar and H2 as a gas source for an outer plasma gas and starting an arc in the reactor to generate a plasma flame, the flow ratio of Ar to H2 is 1.5-2:1, the reactor pressure when starting an arc to generate a plasma flame is 85kPa-120kPa, and the plasma power is 50kW-70kW, which is conducive to obtaining spherical tungsten carbide powder with good sphericity, so that the surface modified tungsten carbide powder subsequently plated with a nickel shell has good fluidity.

[0016] Furthermore, in the step of introducing Ar as a carrier gas to feed the tungsten carbide powder into the reactor, the feeding rate is 10 g / min-15 g / min, which is conducive to obtaining tungsten carbide spherical micropowder with uniform particle size.

[0017] Furthermore, the step of chemically plating a nickel shell layer on the surface of the tungsten carbide spherical powder to obtain the surface-modified tungsten carbide powder comprises:

[0018] The tungsten carbide spherical powder is added to a chemical plating solution at 70° C.-75° C., and the plating is performed under stirring; the chemical plating solution comprises 7 parts of sodium citrate, 10 parts of nickel chloride and 7 parts of sodium hypophosphite by mass, and the pH value of the chemical plating solution is 10.

[0019] The plating solution is removed by filtration, and the filter residue is washed with deionized water and then centrifuged and dried to obtain the surface-modified tungsten carbide micropowder.

[0020] First, a plasma flame is used to melt and spheroidize tungsten carbide, and then a nickel shell is plated by chemical plating. The nickel shell of the surface modified tungsten carbide micropowder is of high purity, and the surface modified tungsten carbide micropowder has few internal pores as a whole, and no "nickel" pool will be formed.

[0021] Furthermore, the stirring plating time is 25 min-45 min, and a nickel shell layer with a thickness of 0.05 μm-0.09 μm can be obtained.

[0022] Furthermore, before adding the tungsten carbide spherical micropowder into the chemical plating solution at 70° C.-75° C., the tungsten carbide spherical micropowder is pretreated with hydrofluoric acid.

[0023] After plasma flame melting and spheroidization, the tungsten carbide spherical powder is relatively dense and has a high sphericity. Etching the surface of tungsten carbide with hydrofluoric acid is conducive to roughening the surface of the tungsten carbide spherical powder, which is convenient for covering with a nickel shell layer.

[0024] Furthermore, in the pretreatment step, the volume concentration of hydrofluoric acid is 2%, and the pretreatment time is 2 min-5 min.

[0025] In a second aspect, the present application provides a double flat position wedge-shaped riving cutter bar stock, which is made by the double flat position wedge-shaped riving cutter bar stock preparation method described in the first aspect and has a high-precision flat position and a center hole.

[0026] Furthermore, the length of the quasi-cylindrical body is 20mm-27mm, and the maximum outer diameter is 1.4mm-2mm; the first flat position is 0.6mm-0.8mm away from the central axis of the quasi-cylindrical body; the second flat position is 13mm-18mm long and 0.3mm-0.5mm away from the central axis of the quasi-cylindrical body; the diameter of the center hole is 0.13mm-0.5mm; based on the central axis of the quasi-cylindrical body, the coaxiality of the first flat position, the second flat position and the center hole is ≤0.05mm, and the true roundness of the center hole is ≤0.03mm; the density of the double flat position wedge-shaped splitting cutter bar is 92%-95%, the hardness is 1100HV-1300HV, and the bending strength is 850MPa-920MPa.

[0027] The beneficial effects of the present invention are as follows: the present invention first performs plasma flame melting and spheroidization on tungsten carbide powder to make it denser and more spherical, and then chemically plates a nickel shell layer, and the obtained cemented carbide can maintain good sphericity and density, and has high hardness. After SLM (selective laser melting) three-dimensional printing, the flat position and center hole of the obtained rod material have high precision, and there will be no problems of hole blocking and perforation steps. The rod material has high density, high hardness and bending strength, which is conducive to positioning during further processing, and is conducive to subsequent precision processing of the splitting cutter head, and has a favorable effect on improving the wear resistance of the splitting cutter and extending its service life.

[0028] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or understood by practicing the present application. The purpose and other advantages of the present application can be realized and obtained by the structures particularly pointed out in the written description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the perforation step defect.

[0030] Figure 2 It is a schematic structural diagram of a double flat position wedge-shaped splitting cutter bar provided in an embodiment of the present application.

[0031] Figure 3 This is a radial cross-sectional view of the rod material obtained in Example 1.

[0032] Figure 4 This is an axial cross-sectional view of the rod material prepared in Comparative Example 1.

[0033] Figure 5 This is a radial cross-sectional view of the rod material obtained in Comparative Example 2.

[0034] Figure numerals: 1. quasi-cylindrical body; 2. first flat position; 3. second flat position; 4. center hole. DETAILED DESCRIPTION

[0035] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0036] The disclosure below provides many different embodiments or examples to implement different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed.

[0037] The traditional process of making splitter bar materials has low precision and low yield rate when making small-sized splitters. The main difficulties lie in the flat position and the center hole, especially the center hole. During the drilling process, if single-through hole processing is used, the processing time is long and the hole is prone to blockage; if through-hole processing is used, such as Figure 1 As shown in the figure, when drilling from both ends, the axes of the two holes are difficult to completely coincide, and it is easy to have a step in the drilling, such as Figure 1 As shown in A, it is not conducive to threading the wire with the splitter. The positional deviation of the flat part mainly affects the subsequent precision machining of the cutter head.

[0038] In view of the above problems, the present invention provides a method for preparing a double flat wedge-shaped splitting cutter bar, comprising the following steps:

[0039] S1: Spheroidize the tungsten carbide powder with a plasma flame to obtain spherical tungsten carbide powder.

[0040] S2: A nickel shell layer is plated on the surface of tungsten carbide spherical powder to obtain surface modified tungsten carbide powder.

[0041] S3: Using surface modified tungsten carbide powder as raw material, SLM technology is used to print a double flat position wedge-shaped splitting knife bar. The 3D printed double flat position wedge-shaped splitting knife bar includes a quasi-cylinder 1, which is provided with a center hole 4 along its own axis. The surface of the quasi-cylinder 1 is provided with a first flat position 2 and a second flat position 3 parallel to each other. The first flat position 2 is equal to the length of the quasi-cylinder 1, and the second flat position 3 extends from one end of the quasi-cylinder 1 to the middle, forming a step with the surface of the quasi-cylinder 1.

[0042] Step S1 first performs plasma flame melting and spheroidization on tungsten carbide powder, and the obtained tungsten carbide spherical powder is denser and has high sphericity than the original tungsten carbide powder; Step S2 chemically plates a nickel shell layer, and on the basis of the tungsten carbide spherical powder with high sphericity, the obtained cemented carbide can maintain good sphericity and density, and has high hardness and does not contain cobalt. After SLM three-dimensional printing in step S3, the flat position and center hole of the obtained rod material have high precision, and there will be no problems of hole blocking and perforation steps. The rod material has high density, hardness and bending strength.

[0043] Specifically, the quasi-cylinder 1 is 20mm-27mm long, and the maximum outer diameter is 1.4mm-2mm; the first flat position 2 is 0.6mm-0.8mm away from the central axis of the quasi-cylinder 1; the second flat position 3 is 13mm-18mm long, and is 0.3mm-0.5mm away from the central axis of the quasi-cylinder 1; the aperture of the center hole 4 is 0.13mm-0.5mm; taking the central axis of the quasi-cylinder 1 as a reference, the coaxiality of the first flat position 2, the second flat position 3, and the center hole 4 are all ≤0.05mm, and the true roundness of the center hole 4 is ≤0.03mm; the density of the double flat position wedge splitting cutter bar is 92%-95%, the hardness is 1100HV-1300HV, and the bending strength is 850MPa-920MPa. The bar material has the advantages of high density, high hardness and high bending strength, which is conducive to positioning during further processing and subsequent precision processing of the chopper head, can improve the wear resistance of the chopper and extend the service life of the chopper.

[0044] The specific steps of step S1 include:

[0045] S11: The reactor is evacuated to a back vacuum of 0.5 Pa, a mixture of Ar and H2 is introduced as an outer plasma gas source, and the reactor is arced to generate a plasma flame;

[0046] S12: Ar is introduced as a carrier gas to feed the tungsten carbide powder into the reactor, so that the melted tungsten carbide powder is cooled and spheroidized under the action of the circulating Ar quenching gas, and the spherical tungsten carbide powder deposited at the bottom of the reactor is collected.

[0047] In step S11, the flow ratio of Ar to H2 is 1.5-2:1, the reactor pressure when the arc is started to generate the plasma flame is 85kPa-120kPa, and the plasma power is 50kW-70kW.

[0048] In step S12, the delivery rate is 10g / min-15g / min.

[0049] The above process of melt spheroidization can obtain tungsten carbide spherical powder with good sphericity and relatively uniform particle size distribution. After the subsequent chemical plating of the nickel shell layer, the surface modified tungsten carbide powder has good fluidity and can be used for high-precision SLM printing.

[0050] The specific steps of step S2 include:

[0051] S21: Add tungsten carbide spherical powder into a chemical plating solution at 70°C-75°C, and stir for plating; the chemical plating solution includes 7 parts of sodium citrate, 10 parts of nickel chloride and 7 parts of sodium hypophosphite by mass, and the pH is adjusted to 10 with sodium hydroxide.

[0052] S22: filtering to remove the plating solution, washing the filter residue with deionized water and centrifugally drying the residue to obtain surface modified tungsten carbide micropowder.

[0053] First, a plasma flame is used to melt and spheroidize tungsten carbide, and then a nickel shell is plated by chemical plating. The nickel shell of the surface modified tungsten carbide micropowder is of high purity, and the surface modified tungsten carbide micropowder has few internal pores as a whole, and no "nickel" pool will be formed.

[0054] In fact, the surface of the tungsten carbide spherical powder after plasma flame melting and spheroidization is relatively smooth, and palladium activation is easy to introduce new impurities, making the purity of the SLM raw material insufficient. In a preferred embodiment, before step S21, there is also a step S20: pre-treating the tungsten carbide spherical powder with hydrofluoric acid. After etching the surface of tungsten carbide with hydrofluoric acid, the surface of the tungsten carbide spherical powder is roughened to facilitate covering with a nickel shell layer.

[0055] However, if the etching degree during pretreatment is too large, the originally good sphericity will be easily destroyed, and even the interior of the SLM raw material will not be dense enough. Preferably, in step S20, the volume concentration of hydrofluoric acid is 2%, and the pretreatment time is 2min-5min.

[0056] Example 1

[0057] Tungsten carbide powder with a particle size of 7μm was selected as the raw material. After the reactor was evacuated to the back vacuum, 80L / min of Ar and 40L / min of hydrogen were continuously introduced. After the pressure reached 100kPa, a power of 60kW was selected to produce a plasma flame. Tungsten carbide powder was continuously introduced at a powder feeding rate of 12.5g / min, and spherical tungsten carbide powder (tungsten carbide spherical micropowder) with an average particle size of 6μm was collected at the bottom of the reactor.

[0058] Use 2% hydrofluoric acid solution for pretreatment for 3 minutes, and then wash with deionized water to neutral to obtain pretreated spherical tungsten carbide powder. Take sodium citrate dihydrate, nickel chloride hexahydrate, and sodium hypophosphite monohydrate to prepare a plating solution, and keep the plating solution at a constant temperature of 70°C in a constant temperature oil bath, and adjust the pH of the plating solution to 10 with sodium hydroxide solution. Pour the pretreated spherical tungsten carbide powder into the plating solution, stir and plate for 25 minutes, then pour out the plating solution, add deionized water for ultrasonic cleaning until neutral, centrifuge, and dry in a vacuum drying oven at 60°C to obtain surface-modified spherical tungsten carbide powder (surface-modified tungsten carbide micropowder).

[0059] The selective laser melting (SLM) system was used to print a bar with a length of 24 mm and a flattened circle diameter (maximum outer diameter of a cylindrical body) of 1.5 mm. The first flattened position 2 was 0.7 mm from the center axis (specifically the center axis of the bar, i.e., the axis of the cylindrical body), the step flattened position (the second flattened position 3) was 15 mm long, 0.4 mm from the center axis, and the center hole 4 had a diameter of 0.22 mm. The laser melting laser power was 140 W, and a double flattened wedge-shaped chopper bar was obtained.

[0060] The quality inspection of the obtained rods showed that the density of the rods was 93.88%, the hardness of the samples was 1149HV, and the bending strength was 878MPa. Figure 3 As shown, the center through hole of the bar is centered and has good roundness, the coaxiality of the first flat position 2 is 0.03mm, the coaxiality of the step flat position is 0.03mm, the coaxiality of the center hole 4 is 0.04mm, and the roundness of the center hole 4 is 0.02mm, which meets the use requirements.

[0061] Example 2

[0062] Tungsten carbide powder with a particle size of 7μm was selected as the raw material. After the reactor was evacuated to the back vacuum, 80L / min of Ar and 40L / min of hydrogen were continuously introduced. After the pressure reached 100kPa, a power of 60kW was selected to produce a plasma flame. Tungsten carbide powder was continuously introduced at a powder feeding rate of 12.5g / min, and spherical tungsten carbide powder with an average particle size of 6μm was collected at the bottom of the reactor.

[0063] Use 2% hydrofluoric acid solution for pretreatment for 3 minutes, and then wash with deionized water to neutral to obtain pretreated spherical tungsten carbide powder. Take sodium citrate dihydrate, nickel chloride hexahydrate, and sodium hypophosphite monohydrate to prepare a plating solution, and keep the plating solution at a constant temperature of 70°C in a constant temperature oil bath, and adjust the pH of the plating solution to 10 with sodium hydroxide solution. Pour the pretreated spherical tungsten carbide powder into the plating solution, stir and plate for 45 minutes, then pour out the plating solution, add deionized water for ultrasonic cleaning until neutral, centrifuge, and dry in a vacuum drying oven at 60°C to obtain surface-modified spherical tungsten carbide powder.

[0064] The selective laser melting (SLM) system was used to print a rod with a length of 21 mm and a flattened circle diameter of 2 mm. The first flattened position 2 was 0.9 mm from the center axis, the step flattened position was 13 mm long and 0.6 mm from the center axis, and the center hole 4 had a diameter of 0.22 mm. The laser melting laser power was 140 W, and a double flattened wedge-shaped chopper rod was obtained.

[0065] The quality inspection of the produced rods showed that the density of the rods was 94.23%, the hardness was 1293HV, the bending strength was 912MPa, the coaxiality of the first flat position 2 was 0.03mm, the coaxiality of the step flat position was 0.04mm, the coaxiality of the center hole 4 was 0.03mm, and the roundness of the center hole 4 was 0.03mm, which met the use requirements.

[0066] Comparative Example 1

[0067] 3% Ni-WC cemented carbide blocks were prepared by traditional powder metallurgy process, with a density of 93.44%, a hardness of 1180 HV, and a bending strength of 890 MPa. High-speed wire cutting and grinding were used to process double flat bar stock with a length of 24 mm and a flat diameter of 1.5 mm. The first flat position 2 was 0.7 mm from the center axis, and the step flat position was 15 mm long and 0.4 mm from the center axis. The center hole with a diameter of 0.22 mm was processed by electrospark machining to obtain a double flat wedge-shaped splitter bar stock.

[0068] The quality inspection of the bar material showed that the coaxiality of the first flattened position 2 of the processed bar material was 0.04mm, and the coaxiality of the step flattened position was 0.05mm. Figure 4 As shown, there are steps on the rod material for perforation, and the size accuracy of the center hole cannot meet the use requirements.

[0069] Comparative Example 2

[0070] 5% Ni-WC cemented carbide powder was prepared by mechanical ball milling. A bar with a length of 21 mm and a flattened circle diameter of 2 mm was printed by a selective laser melting (SLM) system. The first flattened position 2 was 0.9 mm from the center axis, the step flattened position was 13 mm long, 0.6 mm from the center axis, and the center hole 4 had a diameter of 0.22 mm. The laser melting laser power was 140 W, and a double flattened wedge-shaped splitter bar was obtained.

[0071] The obtained bar material is inspected for quality, and its radial cross section is as follows: Figure 5 As shown, the results show that after threading, there is a phenomenon of falling pieces in the center of the bar, the structural strength of the material is low, the central through hole is elliptical in shape, the roundness is poor, the density of the bar is 82%, the hardness is 832HV, the bending strength is 682MPa, and the structural strength of the bar cannot meet the use requirements.

[0072] It can be seen that the embodiment of the present application can obtain a small-sized wedge-shaped splitting cutter bar with high strength and high dimensional accuracy, which is beneficial to improving the service life of the small-sized wedge-shaped splitting cutter.

[0073] In the description of this specification, the description with reference to the terms "one embodiment", "certain embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0074] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for preparing a double flat wedge-shaped splitter bar, characterized in that: The following steps are involved: The tungsten carbide powder is spheroidized by plasma flame to obtain spherical tungsten carbide powder; Chemically plating a nickel shell layer on the surface of the tungsten carbide spherical micropowder to obtain surface-modified tungsten carbide micropowder; The surface modified tungsten carbide powder is used as a raw material, and the double flat position wedge-shaped splitting knife bar is printed by SLM technology; the double flat position wedge-shaped splitting knife bar comprises a quasi-cylindrical body (1), the quasi-cylindrical body (1) is provided with a center hole (4) penetrating along its own axis direction, and the surface of the quasi-cylindrical body (1) is provided with a first flat position (2) and a second flat position (3) parallel to each other, the first flat position (2) is equal to the length of the quasi-cylindrical body (1), and the second flat position (3) extends from one end of the quasi-cylindrical body (1) to the middle; The step of spheroidizing the tungsten carbide powder with a plasma flame to obtain spherical tungsten carbide powder comprises: The reactor was evacuated to a back vacuum of 0.5 Pa, and a mixture of Ar and H2 was introduced as the outer plasma gas source, and the reactor was arced to generate a plasma flame; Ar is introduced as a carrier gas to feed the tungsten carbide powder into the reactor, so that the melted tungsten carbide powder is cooled and spheroidized under the action of the circulating Ar quenching gas, and the spherical tungsten carbide powder deposited at the bottom of the reactor is collected; The Ar and H2 mixed gas is introduced as the outer plasma gas source. In the step of arcing the reactor to generate a plasma flame, the flow ratio of Ar to H2 is 1.5-2:1, the reactor pressure when arcing to generate a plasma flame is 85kPa-120kPa, and the plasma power is 50kW-70kW.

2. The method for preparing a double flat wedge-shaped splitting cutter bar according to claim 1, characterized in that: In the step of introducing Ar as a carrier gas to feed the tungsten carbide powder into the reactor, the powder feeding rate is 10 g / min-15 g / min.

3. The method for preparing a double flat wedge-shaped splitting cutter bar according to claim 1, characterized in that: The step of chemically plating a nickel shell layer on the surface of the tungsten carbide spherical powder to obtain the surface-modified tungsten carbide powder comprises: Add the tungsten carbide spherical powder to a chemical plating solution at 70°C-75°C, and stir for plating; the chemical plating solution comprises 7 parts of sodium citrate, 10 parts of nickel chloride and 7 parts of sodium hypophosphite by mass, and the pH of the chemical plating solution is 10; The plating solution is removed by filtration, and the filter residue is washed with deionized water and then centrifuged and dried to obtain the surface-modified tungsten carbide micropowder.

4. The method for preparing a double flat wedge-shaped splitting cutter bar according to claim 3, characterized in that: The duration of the stirring plating is 25min-45min.

5. The method for preparing a double flat wedge-shaped splitting cutter bar according to claim 3, characterized in that: Before adding the tungsten carbide spherical micropowder into the chemical plating solution at 70° C.-75° C., the tungsten carbide spherical micropowder is pretreated with hydrofluoric acid.

6. The method for preparing a double flat wedge-shaped splitting cutter bar according to claim 5, characterized in that: In the pretreatment step, the volume concentration of hydrofluoric acid is 2%, and the pretreatment time is 2 min-5 min.

7. A double flat wedge-shaped splitter bar, characterized in that: The double flat wedge-shaped splitting cutter bar is made by the double flat wedge-shaped splitting cutter bar preparation method described in any one of claims 1 to 6.

8. The double flat wedge-shaped splitting tool bar according to claim 7, characterized in that: The quasi-cylindrical body (1) is 20 mm to 27 mm long and has a maximum outer diameter of 1.4 mm to 2 mm. The first flat position (2) is 0.6 mm to 0.8 mm away from the central axis of the quasi-cylindrical body (1). The second flat position (3) is 13 mm to 18 mm long and is 0.3 mm to 0.5 mm away from the central axis of the quasi-cylindrical body (1). The diameter of the central hole (4) is 0.13 mm to 0.5 mm. With the central axis of the quasi-cylindrical body (1) as a reference, the coaxiality of the first flat position (2), the second flat position (3) and the central hole (4) is ≤0.05 mm, and the roundness of the central hole (4) is ≤0.03 mm. The density of the double flat position wedge-shaped splitting cutter bar is 92% to 95%, the hardness is 1100 HV to 1300 HV, and the bending strength is 850 MPa to 920 MPa.

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