A method for preparing a diamond composite cutter head

Abstract

The invention discloses a method for preparing a diamond composite cutter head, which belongs to the technical field of diamond tool preparation, and comprises the following steps: step S1: mixing working layer powder: adding working layer powder and molding agent into a mixer, mixing evenly, and preparing working layer powder; step S2: pressing diamond composite small balls; step S3: rapid sintering; step S4: shaping and polishing; step S5: mixing matrix powder and diamond composite small balls; step S6: pressing diamond composite cutter head; step S7: sintering diamond composite cutter head. The invention can improve the uniformity of diamond distribution in the matrix, effectively avoid the occurrence of agglomeration and segregation problems, improve the density and strength of the wrapping layer, and effectively improve the processing efficiency and service life of the diamond cutter head.

Description

Technical Field

[0001] The invention belongs to the technical field of diamond tool preparation, and in particular relates to a method for preparing a diamond composite tool head. Background Art

[0002] Since the industrialization of artificial diamonds in the 1960s, diamonds have been widely used in various fields due to their unique hardness and wear resistance, especially in the field of diamond tool preparation. Diamond tools have become the first choice for processing hard material tools with their efficient processing capabilities and long service life, such as saw blades, drill bits, grinding discs, grinding heads, etc. They play an important role in construction, stone processing, glass cutting and other fields.

[0003] With the development of diamond tools, the market has higher and higher performance requirements for diamond tools, and diamond segments are key components to achieve the processing performance of diamond tools. They are usually made of a mixture of various metal powders and diamonds through pressing and sintering. After decades of development, the formula and process of diamond segments have become similar. It is difficult to significantly improve the performance of diamond segments by changing the type or composition of the matrix powder.

[0004] Conventional diamond segments are made by mixing and sintering diamond and metal matrix powder. Diamond is randomly distributed in the metal matrix powder, and the metal matrix powder serves as a medium to support and fix the diamond. Due to the large difference in particle size and density between diamond and metal matrix powder, it is difficult to mix diamond evenly in the metal matrix powder. Randomly distributed diamonds are prone to agglomeration and segregation, which greatly affects the performance of diamond segments and easily leads to reduced processing efficiency, shortened service life and instability of diamond segments.

[0005] In order to solve the above problems, diamond coating technology came into being. By coating the surface of diamond particles with a layer of metal powder, on the one hand, the uniformity of diamond dispersion in the matrix can be improved, and the use effect of diamond bits can be improved. On the other hand, the micro-environment around the diamond can be improved, and its performance can be further improved. However, in the current diamond coating process, the metal powder is loosely distributed on the periphery of the diamond particles, which makes the powder layer coated on the diamond particles low in density and strength, and easy to break, crack, and fall off, which seriously affects the use effect of the coated diamond.

[0006] Therefore, there is a need for a method for preparing a diamond composite tool head that can improve the uniformity of diamond distribution in the matrix, increase the density and strength of the coating layer, and effectively improve the processing efficiency and service life of the diamond tool head. Summary of the invention

[0007] The purpose of the present invention is to provide a method for preparing a diamond composite tool head, which can improve the uniformity of diamond distribution in the matrix, effectively avoid the occurrence of agglomeration and segregation problems, improve the density and strength of the coating layer, and effectively improve the processing efficiency and service life of the diamond tool head.

[0008] To achieve the above purpose, the technical solution adopted by the present invention is: A method for preparing a diamond composite tool head comprises the following steps: Step S1: Working layer powder mixing: adding working layer powder and molding agent into a mixer, mixing evenly, and preparing working layer powder; Step S2: Pressing diamond composite balls: Loading the working layer powder into a steel mold, arranging the diamonds in the working layer powder through a porous diamond template with negative pressure, and pressing the working layer powder into a ball containing a diamond under pressing pressure and pressing temperature; Step S3: Rapid sintering: The pressed diamond composite balls are placed in a rapid sintering mold with a protective atmosphere, and the diamond composite balls are sintered by applying high temperature and high pressure; Step S4: shaping and polishing: the sintered diamond composite balls and abrasives are placed in a stirring mixer for shaping and polishing. After stirring, the excess abrasives are sieved out with a sieve to obtain the shaped and polished diamond composite balls. Step S5: Mixing the matrix powder and the diamond composite balls: putting the matrix powder and the diamond composite balls into a mixer and mixing them evenly; Step S6: Pressing the diamond composite cutter head: loading the matrix powder mixed with diamond composite balls into a steel mold for pressing the cutter head, applying a pressure of 300-500 MPa to complete the pressing of the diamond composite cutter head; Step S7: Sintering of the diamond composite blade head: The pressed blade head is placed in a graphite mold, and the temperature is raised to 860-880° C. using a hot press, the sintering pressure is 30-40 MPa, and the temperature is kept for 1-3 minutes to complete the sintering of the diamond composite blade head.

[0009] A further improvement of the technical solution of the present invention is that in step S1, the working layer powder includes any combination of 50-100% Co powder, 5-30% WC powder, 5-20% CuSn alloy powder and 20-60% FeCoCu alloy powder in a mass ratio.

[0010] The further improvement of the technical solution of the present invention is that in step S1, the particle size of the working layer powder is between 0.5μm and 40μm, the molding agent is one or more of wax powder, polyethylene glycol, polyamide, and polyethylene; the mixer can be a planetary ball mill, and the mixing time is 1h-3h.

[0011] A further improvement of the technical solution of the present invention is that in step S2, the steel mold includes a female mold with a plurality of evenly arranged circular holes and punching plates correspondingly arranged on the upper and lower sides of the female mold, and the punching plates are provided with a plurality of punches corresponding to the circular holes on the female mold, and shrinkage seams are provided between the circular holes in each row on the female mold.

[0012] A further improvement of the technical solution of the present invention is that in step S2, the porous diamond template is matched with the female mold of the steel mold, and the porous diamond template is provided with a plurality of through holes corresponding to the positions of the circular holes on the female mold.

[0013] A further improvement of the technical solution of the present invention is that in step S2, pressing the diamond composite ball comprises the following steps: Step S201: Loading the working layer powder into each circular hole of the female mold of the steel mold; Step S202: loading diamonds into each through hole of a porous diamond template with negative pressure; Step S203: placing a porous diamond template with negative pressure on the female mold, ensuring that the through holes on the porous diamond template are aligned with the circular holes on the female mold, and then sucking the diamonds out of the porous diamond template by negative pressure and arranging them in the working layer powder of the female mold; Step S204: Use the punch plates on the upper and lower sides to apply pressure to the female mold so that the working powder and the diamond are tightly combined to form a diamond composite ball.

[0014] The further improvement of the technical solution of the present invention is that: in step S2, the diameter of the circular hole on the female mold is 0.4mm-3mm, and the width of the shrinkage seam is 0.05-0.15mm; the diameter of the through hole on the porous diamond template is 0.2mm-2mm, and the material of the porous diamond template is one of aluminum alloy, brass, and Cr12 steel; the particle size of the diamond is 18 mesh-120 mesh, and the diameter of the small ball containing a diamond is 0.4mm-3mm; the pressing pressure is 200MPa-600MPa, and the pressing temperature is 120℃-180℃.

[0015] A further improvement of the technical solution of the present invention is that in step S3, the protective atmosphere is one of Ar, N2 or He; the rapid sintering temperature is 750°C-1050°C, the sintering pressure is 10MPa-100MPa, and the sintering insulation time is 30s-180s.

[0016] A further improvement of the technical solution of the present invention is that: in step S4, the abrasive is one of silicon carbide, aluminum oxide, boron carbide and silicon oxide; and the stirring time is 10 minutes to 45 minutes.

[0017] A further improvement of the technical solution of the present invention is that in step S5, the matrix powder includes any combination of 30-100% Fe powder, 10-60% Cu powder, 0.5-10% Sn powder, 40-100% FeCu alloy powder, and 5-20% WC powder in a mass ratio, and the added amount of diamond composite balls is 5%-95%.

[0018] Due to the adoption of the above technical solution, the technical progress achieved by the present invention is: The preparation method of the diamond composite cutter head of the present invention can improve the uniformity of the distribution of diamonds in the matrix, effectively avoid the occurrence of agglomeration and segregation problems, improve the density and strength of the coating layer, and effectively improve the processing efficiency and service life of the diamond cutter head. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a process flow chart of the method for preparing the diamond composite tool head of the present invention; Figure 2 It is a schematic structural diagram of a female mold in a steel mold used in the present invention; Figure 3 It is a schematic diagram of the structure of the punch plate in the steel mold used in the present invention; Figure 4 It is a schematic diagram of the structure of the porous diamond template used in the present invention; Figure 5 is a schematic diagram of the diamond composite ball obtained in the present invention; Figure 6 is a fracture morphology diagram of the diamond composite tool head obtained in the present invention; Figure 7 is a comparison curve of the drilling and cutting speed of the diamond composite drill bit prepared in Example 1 of the present invention and the ordinary drill bit; Figure 8 is a comparison curve of the cutting speed of the diamond composite saw blade segment prepared in Example 2 of the present invention and the ordinary saw blade segment; Among them, 1. circular hole, 2. female die, 3. punch plate, 4. shrinkage seam, 5. through hole, 6. punch. DETAILED DESCRIPTION

[0020] The present invention is further described in detail below in conjunction with embodiments: like Figure 1 As shown, the present invention provides a method for preparing a diamond composite tool head, comprising the following steps: Step S1: Working layer powder mixing: adding working layer powder and molding agent into a mixer for 1-3 hours, mixing evenly, and preparing working layer powder; The working layer powder includes any combination of Co powder, WC powder, CuSn alloy powder and FeCoCu alloy powder in a mass ratio of 50-100%, 5-30%, 5-20% and 20-60% respectively; the particle size of the working layer powder is between 0.5 μm and 40 μm; the molding agent is one or more of wax powder, polyethylene glycol, polyamide and polyethylene; the mixer can be a planetary ball mill; Step S2: Pressing diamond composite balls: loading the working layer powder into a steel mold, arranging the diamonds in the working layer powder through a porous diamond template with negative pressure, and pressing the working layer powder into balls containing one diamond at a pressing pressure of 200MPa-600MPa and a pressing temperature of 120°C-180°C; wherein the diamond particle size is 18-120 mesh, and the diameter of the ball containing one diamond is 0.4mm-3mm; Specifically, Figure 2 and Figure 3 As shown, the steel mold includes a female mold 2 having a plurality of evenly arranged circular holes 1 and punch plates 3 correspondingly arranged on the upper and lower sides of the female mold 2, and the punch plates 3 are provided with a plurality of punches 6 corresponding to the circular holes 1 on the female mold 2, and an arc-shaped groove adapted to a small ball is provided on the top of the punch 6, and a shrinkage seam 4 is provided between the circular holes 1 in each row on the female mold 2, wherein the diameter of the circular hole 1 ranges from 0.4 mm to 3 mm, and the width of the shrinkage seam 4 is 0.05-0.15 mm, and the material of the steel mold can be one of Cr12, Crl3, 1Cr18Ni9Ti, 0Cr25Ni20, and 42CrMo4; like Figure 4 As shown, the porous diamond template is adapted to the female mold of the steel mold, and a plurality of through holes 5 corresponding to the positions of the circular holes 1 on the female mold 2 are opened on the porous diamond template, and the diameter of the through holes 5 is 0.2mm-2mm, and the material of the porous diamond template is one of aluminum alloy, brass, and Cr12 steel; Pressing the diamond composite ball specifically includes the following steps: Step S201: Load the working layer powder into each circular hole 1 of the female mold 2 of the steel mold; Step S202: loading diamonds into each through hole 5 of the porous diamond template with negative pressure; Step S203: placing a porous diamond template with negative pressure on the female mold 2, ensuring that the through holes 5 on the porous diamond template are aligned with the circular holes 1 on the female mold 2, and then sucking the diamonds out of the porous diamond template by negative pressure and arranging them in the working layer powder of the female mold 2; Step S204: Use the punch plates 3 on the upper and lower sides to apply pressure to the female mold 2 to make the working powder and diamonds tightly combine to form a diamond composite ball. Figure 5 As shown; Step S3: rapid sintering: the pressed diamond composite ball is loaded into a rapid sintering mold with a protective atmosphere, and the diamond composite ball is sintered by applying high temperature and high pressure; wherein the protective atmosphere is one of Ar, N2 or He; the rapid sintering temperature is 750°C-1050°C, the sintering pressure is 10MPa-100MPa, and the sintering holding time is 30s-180s; Step S4: shaping and polishing: the sintered diamond composite ball and abrasive are placed in a stirring and mixing device for shaping and polishing. After stirring for 10-45 minutes, the excess abrasive is sieved out with a sieve to obtain the diamond composite ball after shaping and polishing. The abrasive is one of silicon carbide, aluminum oxide, boron carbide and silicon oxide. The stirring and mixing device can be a multifunctional mixer SYS-304-1. Step S5: Mixing matrix powder and diamond composite balls: loading matrix powder and diamond composite balls into a mixer and mixing them evenly; wherein the matrix powder includes any combination of 30-100% Fe powder, 10-60% Cu powder, 0.5-10% Sn powder, 40-100% FeCu alloy powder, and 5-20% WC powder in a mass ratio, and the addition amount of diamond composite balls is 5%-95%; Step S6: Pressing the diamond composite cutter head: loading the matrix powder mixed with diamond composite balls into a steel mold for pressing the cutter head, applying a pressure of 300-500 MPa to complete the pressing of the diamond composite cutter head; Step S7: Sintering of the diamond composite blade: The pressed blade is placed in a graphite mold, heated to 860-880°C by a hot press, with a sintering pressure of 30-40 MPa, and kept warm for 1-3 minutes to complete the sintering of the diamond composite blade. The fracture morphology of the obtained diamond composite blade is as follows: Figure 6 shown.

[0021] Example 1 The present embodiment provides a method for preparing a diamond composite drill bit, which comprises the following steps: Step S1: Working layer powder mixing: The working layer powder is selected from 60-80% Co powder and 10-20% WC powder with a particle size of 0.5 μm-1.0 μm, and is added into a planetary ball mill together with the molding agent wax powder, and mixed for 1 hour to complete the preparation of the working layer powder; Step S2: Pressing diamond composite balls: using a Cr12 steel mold with a circular hole 1 on a female mold 2 and a diameter of 1.5 mm, using 35 / 40 ZND2290 diamond as diamond, and a through hole 5 on a porous diamond template with a diameter of 0.4±0.05 mm, loading the working layer powder into the steel mold, arranging the diamonds in the working layer powder through the porous diamond template with negative pressure, and pressing the working layer powder into a 1.5 mm ball containing one diamond at a pressing pressure of 300 MPa and a pressing temperature of 180°C; Step S3: Rapid sintering: The pressed diamond composite pellets are placed in a rapid sintering mold protected by Ar gas, and the diamond composite pellets are sintered and kept warm for 180 seconds at a sintering temperature of 900° C. and a sintering pressure of 30 MPa to complete the sintering of the diamond composite pellets; Step S4: shaping and polishing: the sintered diamond composite ball and 80-mesh silicon carbide abrasive are placed in a stirring mixer, stirred for 10 minutes, and then the silicon carbide abrasive is sieved out with a 50-mesh sieve to obtain the shaped and polished diamond composite ball; Step S5: Mixing matrix powder with diamond composite balls: Putting matrix powder including 80-90% Fe powder, 10-30% Cu powder, 1-3% Sn powder and 5-10% diamond composite balls into a planetary ball mill and mixing them evenly; Step S6: Pressing the diamond composite drill bit: putting the matrix powder mixed with diamond composite balls into a steel mold for pressing the drill bit, applying a pressure of 300-500 MPa to complete the pressing of the drill bit; Step S7: Sintering of the diamond composite blade: The pressed blade is placed in a graphite mold, heated to 860-880°C by a hot press, with a sintering pressure of 30-40 MPa, and kept warm for 1-3 minutes to complete the sintering of the diamond composite blade. The fracture morphology of the obtained diamond composite blade is as follows: Figure 6 shown.

[0022] The diamond composite cutter head prepared in this embodiment was welded to a 63-gauge drill pipe to prepare a 63-gauge drill head, and a performance test was conducted to compare the performance of the 63-gauge drill head prepared by the conventional process. The drill rig used in the test was a self-produced Z1Z-200N drill rig with a rated power of 3200W and a rated speed of 580r / min. A self-made reinforced concrete test block (15cm thick, three layers of φ25 threaded steel bars, concrete grade C40) was wet drilled with water to test the performance of the diamond composite cutter head prepared in this embodiment and the conventional cutter head. The test results are shown in FIG. Figure 7 As shown in the figure, the average cutting speed of the drill bit made of diamond composite cutter head is 5.29 cm / min, and the life is 1.5 m / mm. The average cutting speed of the ordinary drill bit is 3.43 cm / min, and the life is 1 m / mm. The cutting speed and life are both increased by about 50%.

[0023] Example 2 This embodiment provides a method for preparing a diamond composite saw blade segment. The method steps other than step S1 and step S5 are the same as those in embodiment 1, except that: In step S1, the working layer powder is selected from 20-40% Co powder with a particle size of 0.5μm-1.0μm, 10-20% CuSn alloy powder with a particle size of 1μm-10μm, and 20-40% FeCoCu alloy powder; in step S5, the matrix powder including 40-50% Fe powder, 50-60% FeCu alloy powder, 5-10% WC powder and 5-10% diamond composite balls are added into a planetary ball mill and mixed evenly.

[0024] The diamond composite blade and ordinary blade prepared in this embodiment are made into φ350 saw blades, and a high-speed table saw is used for cutting test. The rated power of the saw is 7500W, the rated speed is 2350r / min, and 15cm thick C40 concrete is cut with water. Each saw blade cuts 50m, each blade is 1m long, and each saw blade cuts 50 blades. The test results are as follows: Figure 8 The average cutting speed of the composite saw blade made of diamond composite cutter head is 1.38m / min, and the service life is 100m / mm. The average cutting speed of the ordinary saw blade is 0.7m / min, and the service life is 55.56m / mm. The cutting speed is increased by 95%, and the service life is increased by 80%.

[0025] In summary, the preparation method of the diamond composite cutter head of the present invention can improve the uniformity of the distribution of diamonds in the matrix, effectively avoid the occurrence of agglomeration and segregation problems, improve the density and strength of the coating layer, and effectively improve the processing efficiency and service life of the diamond cutter head.

[0026] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. A method for preparing a diamond composite tool head, characterized in that The following steps are involved: Step S1: Working layer powder mixing: adding working layer powder and molding agent into a mixer, mixing evenly, and preparing working layer powder; Step S2: Pressing diamond composite balls: Loading the working layer powder into a steel mold, arranging the diamonds in the working layer powder through a porous diamond template with negative pressure, and pressing the working layer powder into a ball containing a diamond under pressing pressure and pressing temperature; Step S3: Rapid sintering: The pressed diamond composite balls are placed in a rapid sintering mold with a protective atmosphere, and the diamond composite balls are sintered by applying high temperature and high pressure; Step S4: shaping and polishing: the sintered diamond composite balls and abrasives are placed in a stirring mixer for shaping and polishing. After stirring, the excess abrasives are sieved out with a sieve to obtain the shaped and polished diamond composite balls. Step S5: Mixing the matrix powder and the diamond composite balls: putting the matrix powder and the diamond composite balls into a mixer and mixing them evenly; Step S6: Pressing the diamond composite cutter head: loading the matrix powder mixed with diamond composite balls into a steel mold for pressing the cutter head, applying a pressure of 300-500 MPa to complete the pressing of the diamond composite cutter head; Step S7: Sintering of the diamond composite blade head: The pressed blade head is placed in a graphite mold, and the temperature is raised to 860-880° C. using a hot press, the sintering pressure is 30-40 MPa, and the temperature is kept for 1-3 minutes to complete the sintering of the diamond composite blade head.

2. The method for preparing a diamond composite tool head according to claim 1, characterized in that: In step S1 , the working layer powder includes any combination of 50-100% Co powder, 5-30% WC powder, 5-20% CuSn alloy powder and 20-60% FeCoCu alloy powder in a mass ratio.

3. The method for preparing a diamond composite tool head according to claim 2, characterized in that: In step S1, the particle size of the working layer powder is between 0.5 μm and 40 μm, and the molding agent is one or more of wax powder, polyethylene glycol, polyamide, and polyethylene; the mixer can be a planetary ball mill, and the mixing time is 1 h to 3 h.

4. The method for preparing a diamond composite tool head according to claim 1, characterized in that: In step S2, the steel mold comprises a female mold (2) having a plurality of evenly arranged circular holes (1) therethrough and punch plates (3) correspondingly arranged on the upper and lower sides of the female mold (2), and the punch plates (3) are provided with a plurality of punches (6) corresponding to the circular holes (1) on the female mold (2), and shrinkage seams (4) are provided between the circular holes (1) in each row on the female mold (2).

5. The method for preparing a diamond composite tool head according to claim 4, characterized in that: In step S2, a porous diamond template is matched with a female mold (2) of a steel mold, and a plurality of through holes (5) corresponding to the positions of the circular holes (1) on the female mold (2) are formed on the porous diamond template.

6. The method for preparing a diamond composite tool head according to claim 5, characterized in that: In step S2, pressing the diamond composite ball includes the following steps: Step S201: loading the working layer powder into each circular hole (1) of the female mold (2) of the steel mold; Step S202: loading diamonds into each through hole (5) of the porous diamond template with negative pressure; Step S203: placing a porous diamond template with negative pressure on the female mold (2), ensuring that the through holes (5) on the porous diamond template are aligned with the circular holes (1) on the female mold (2), and then sucking the diamonds out of the porous diamond template by negative pressure and arranging them in the working layer powder of the female mold (2); Step S204: using the punch plates (3) on the upper and lower sides to apply pressure to the female mold (2) so that the working powder and the diamond are tightly combined to form a diamond composite ball.

7. The method for preparing a diamond composite tool head according to claim 6, characterized in that: In step S2, the diameter of the circular hole (1) on the female mold (2) is 0.4 mm-3 mm, and the width of the shrinkage gap (4) is 0.05-0.15 mm; the diameter of the through hole (5) on the porous diamond template is 0.2 mm-2 mm, and the material of the porous diamond template is one of aluminum alloy, brass, and Cr12 steel; the particle size of the diamond is 18 mesh-120 mesh, and the diameter of the small ball containing a diamond is 0.4 mm-3 mm; the pressing pressure is 200 MPa-600 MPa, and the pressing temperature is 120° C.-180° C.

8. The method for preparing a diamond composite tool head according to claim 1, characterized in that: In step S3, the protective atmosphere is one of Ar, N2 or He; the rapid sintering temperature is 750°C-1050°C, the sintering pressure is 10MPa-100MPa, and the sintering holding time is 30s-180s.

9. The method for preparing a diamond composite tool head according to claim 1, characterized in that: In step S4, the abrasive is one of silicon carbide, aluminum oxide, boron carbide and silicon oxide; and the stirring time is 10 min-45 min.

10. The method for preparing a diamond composite tool head according to claim 1, characterized in that: In step S5, the matrix powder includes any combination of 30-100% Fe powder, 10-60% Cu powder, 0.5-10% Sn powder, 40-100% FeCu alloy powder, and 5-20% WC powder in a mass ratio, and the added amount of diamond composite balls is 5%-95%.

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