Highly impact-resistant and anti-falling polycrystalline diamond carbide pick head and manufacturing method thereof

Abstract

The present invention discloses a highly impact-resistant and anti-shedding polycrystalline diamond carbide pick head, comprising a carbide substrate and a polycrystalline diamond layer compounded on the head of the carbide substrate, wherein the polycrystalline diamond layer is an N-layer structure, wherein N is greater than or equal to 2, wherein the top of the polycrystalline diamond layer is in the shape of a spherical crown, and the belly of the polycrystalline diamond layer is a spherical surface formed by a circular arc rotation, and the top spherical surface radius of the polycrystalline diamond layer is less than or equal to the belly spherical surface radius; the carbide substrate is provided with a top, a middle and a bottom, wherein the top of the carbide substrate is compounded with a polycrystalline diamond layer, and the middle part of the carbide substrate is a truncated cone structure, and the upper bottom surface radius of the middle truncated cone of the carbide substrate is less than the lower bottom surface radius. The highly impact-resistant and anti-shedding polycrystalline diamond carbide pick head proposed by the present invention can effectively improve the impact resistance of the composite tooth head, and at the same time enhance the tooth fixing force of the diamond tooth head.

Description

Technical Field

[0001] The invention relates to the technical field of superhard composite materials, and in particular to a highly impact-resistant and anti-shedding polycrystalline diamond carbide pick head and a manufacturing method thereof. Background Art

[0002] Traditional coal and mineral drilling, tunnel and roadway excavation, road milling and other engineering construction basically use carbide pick heads. However, carbide pick heads have problems such as low wear resistance and short life during use, especially when encountering hard or complex rock formations, their life is almost calculated by minutes and footage by meters, resulting in high comprehensive use costs and low efficiency. For this reason, many manufacturers are committed to the research and development of polycrystalline diamond carbide composite pick heads (hereinafter referred to as "diamond tooth heads") to replace carbide tooth heads. Existing diamond tooth heads are generally sintered by a carbide matrix similar to the tooth head shape and diamond powder at the end of the matrix, achieving high wear resistance of the diamond layer, but due to the inherent differences in physical indicators such as thermal expansion coefficient and elastic modulus between diamond materials and carbide materials, and the thinness of diamond powder, especially the powder at the top of the tooth head, the impact resistance of the diamond tooth head is low, which makes it difficult to meet the high-frequency impact conditions of the pick. At the same time, diamond materials produce graphitization and high-temperature thermal damage when exposed to temperatures above 850°C in the air, resulting in the diamond-toothed pick (hereinafter referred to as "diamond pick") being unable to be welded using the high-temperature process of more than 900°C, which is common for carbide-toothed picks. Therefore, the welding firmness and heat resistance of the diamond tooth head on the diamond pick also become key factors restricting the subsequent performance of the pick construction application.

[0003] According to the material and structural characteristics of diamond tooth heads, the appropriate welding temperature should not exceed 700°C. The existing diamond tooth head base welding part is usually a cylindrical structure with weak tooth fixing force. In addition, the relatively low welding temperature, sand inclusion, micro cracks, cold welding and other problems that are easy to occur during welding, as well as strong impact loads during use, lead to frequent desoldering and falling off of diamond tooth heads during construction.

[0004] At present, a variety of measures have been proposed to address the problem of tooth stripping in the engineering application of diamond picks, such as cold press interference fit, hot press interference fit, flame brazing, induction brazing, vacuum diffusion welding, etc. The results are uneven and it is difficult to fundamentally solve the problem. In response to the problem of insufficient impact resistance of diamond tooth heads during diamond pick welding and application, many measures have also been proposed, such as: adding various protrusions and ridges to the interface between the substrate and the diamond layer to enhance the bonding force between the two. Changing the shape or structure of the diamond tooth head to reduce the impact strength and force distribution of the tooth head during use. These measures are beneficial to improving the static adhesion of the diamond layer, but are not sufficient to fundamentally improve the impact resistance of the diamond tooth head. Summary of the invention

[0005] The main purpose of the present invention is to provide a highly impact-resistant and anti-falling polycrystalline diamond carbide pick head and a manufacturing method thereof, aiming to effectively improve the impact resistance of the composite tooth head and at the same time enhance the tooth fixing force of the diamond tooth head to minimize the risk of the diamond tooth head falling off.

[0006] To achieve the above object, the present invention provides a highly impact-resistant and anti-shedding polycrystalline diamond carbide pick head, comprising a carbide substrate and a polycrystalline diamond layer composited to the head of the carbide substrate, wherein:

[0007] The polycrystalline diamond layer has an N-layer structure, N is greater than or equal to 2, the top of the polycrystalline diamond layer is in the shape of a spherical crown, the abdomen of the polycrystalline diamond layer is a spherical surface formed by rotating a circular arc, the top and abdomen of the polycrystalline diamond layer are smoothly transitioned through fillets, and the top spherical surface radius of the polycrystalline diamond layer is less than or equal to the abdomen spherical surface radius;

[0008] The cemented carbide substrate is provided with a top, a middle part and a bottom part. The top part of the cemented carbide substrate is compounded with a polycrystalline diamond layer. The middle part of the cemented carbide substrate is a truncated cone structure. The bottom part of the cemented carbide substrate is a truncated cone structure with at least two layers. The upper bottom radius of the middle truncated cone of the cemented carbide substrate is smaller than the lower bottom radius.

[0009] Preferably, the spherical surface radius of the spherical cap structure at the top of the polycrystalline diamond layer is 0.5 mm-5 mm, and the spherical surface radius of the abdomen of the polycrystalline diamond layer is 5 mm-45 mm.

[0010] Preferably, the top of the cemented carbide substrate is a truncated cone structure, the upper bottom surface and the side surface of the top truncated cone of the cemented carbide substrate smoothly transition through an arc, and the bottom surface radius of the top truncated cone of the cemented carbide substrate is smaller than the lower bottom surface radius.

[0011] Preferably, the corresponding hypotenuse angle of the longitudinal section of the top cone of the cemented carbide substrate is 30°-150°, and a convex ridge is provided on the side of the top cone of the cemented carbide substrate. The cross section of the ridge is arc-shaped, and the edge of the ridge smoothly transitions to the side of the cone.

[0012] Preferably, the arc radius of the convex ridge is 0.1 mm-3 mm, and the protrusion height of the convex ridge perpendicular to the side surface of the frustum is 0.1 mm-3 mm.

[0013] Preferably, the lower bottom surface of the top cone of the cemented carbide substrate and the upper bottom surface of the middle cone are in the same plane, and the radius of the lower bottom surface of the top cone is less than or equal to the radius of the upper bottom surface of the middle cone; the corresponding hypotenuse angle α2 of the longitudinal section of the middle cone of the cemented carbide substrate is 0.5°-45°.

[0014] Preferably, the thickness of the polycrystalline diamond layer is greater than or equal to 2 mm; the polycrystalline diamond layer is formed by mixed sintering of micron and / or nanometer-sized diamond, tungsten carbide, cobalt, tungsten and nickel, wherein the average particle size value of the powder in the Nth layer is greater than or equal to the N-1th layer, and the percentage value of the diamond powder content in the powder in the Nth layer is less than or equal to the N-1th layer.

[0015] Preferably, the tops of the 2nd to Nth layers of the polycrystalline diamond layer are all circular platforms, the abdomens of the 2nd to Nth layers of the polycrystalline diamond layer are all spherical surfaces formed by one rotation of a circular arc, the tops and abdomens of the 2nd to Nth layers of the polycrystalline diamond layer are smoothly transitioned through rounded corners, the radius of the circular platform on the top of the N-1th layer is less than or equal to that of the Nth layer, and the radius of the spherical surface of the abdomen of the Nth layer is greater than or equal to the radius of the spherical surface of the abdomen of the N-1th layer.

[0016] The present invention further proposes a method for preparing the high impact resistance and anti-falling polycrystalline diamond carbide pick head based on the above, comprising the following steps:

[0017] The top of the cemented carbide substrate is sandblasted, ultrasonically cleaned, and dried for later use;

[0018] The powders used for different layers of the polycrystalline diamond layer are mixed separately, and the mixed powders are weighed and loaded into a metal cup for compaction and molding, and each powder layer is prepared by molding from the outside to the inside;

[0019] The formed diamond layer N powder is placed on the processed cemented carbide substrate, and the cemented carbide substrate, the diamond mixed powder and the metal cup are compacted to form a composite mold assembly 1#;

[0020] The compacted assembly 1# is subjected to high temperature vacuum purification treatment;

[0021] The assembly 1# after high temperature purification treatment is loaded into the synthetic mold to form a complete diamond tooth head synthetic mold assembly 2#;

[0022] The assembly 2# is sintered on a six-sided hydraulic press at high temperature and high pressure to obtain a diamond tooth head blank;

[0023] The diamond tooth head blank is processed into a finished diamond tooth head with required dimensions through diamond end face sandblasting, external cylindrical grinding, and carbide end face plane and chamfer grinding.

[0024] Preferably, during the high temperature vacuum purification process, the temperature is 500°C-900°C and the vacuum value is 10 -2 Pa-10 -4 Pa; when sintered at high temperature and high pressure, when placed in the pressure chamber of a six-sided hydraulic press, the temperature is set to 1300℃-1700℃ and the pressure is set to 4.5GPa-8.5GPa.

[0025] The highly impact-resistant and anti-falling polycrystalline diamond carbide pick head proposed by the present invention has the following beneficial effects:

[0026] 1. By setting a transition layer structure with multiple layers of composition and structure on the diamond layer of the diamond pick, especially setting a multi-layer and thickened transition layer structure on the top of the pick, a smooth transition of elastic modulus and thermal expansion coefficient between the diamond surface layer, especially the tooth head, and the cemented carbide layer is effectively achieved, so that the overall impact strength of the composite pick is greatly enhanced;

[0027] 2. By improving the central welding part of the diamond tooth head from a cylindrical structure to a truncated cone structure, and the radius of the upper bottom surface of the central truncated cone is smaller than the radius of the lower bottom surface, this structure enhances the welding firmness of the tooth head in the tooth hole of the pick, and can effectively reduce the risk of the tooth head falling off under high-frequency external force impact during excavation and milling, and effectively improve the high efficiency and low cost advantages of diamond picks in engineering construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic cross-sectional structure diagram of a first embodiment of a highly impact-resistant and anti-shedding polycrystalline diamond carbide pick head of the present invention;

[0029] Figure 2 It is a schematic diagram of the appearance structure of the cemented carbide substrate in the first embodiment of the high impact resistance and anti-falling polycrystalline diamond cemented carbide pick head of the present invention;

[0030] Figure 3 It is a schematic cross-sectional structure diagram of a second embodiment of a highly impact-resistant and anti-falling polycrystalline diamond carbide pick head of the present invention;.

[0031] Figure 4 It is a schematic cross-sectional structure diagram of the diamond tooth head synthetic die assembly 2# of the present invention;

[0032] Figure 5 The present invention is a schematic flow chart of a method for manufacturing a highly impact-resistant and anti-shedding polycrystalline diamond carbide pick head.

[0033] In the figure, 1-hard alloy substrate, 11-top of hard alloy substrate, 111-convex ridge, 12-middle part of hard alloy substrate, 13-bottom of hard alloy substrate, 131-first bottom truncated cone, 132-second bottom truncated cone, 2-polycrystalline diamond layer, 21-top of polycrystalline diamond layer, 22-belly of polycrystalline diamond layer, 200-first layer of polycrystalline diamond layer, 201-second layer of polycrystalline diamond layer, 2011-circular platform, 202-third layer of polycrystalline diamond layer, 30-conductive steel ring, 31-metal sheet, 32-graphite sheet, 33-graphite ring, 34-sodium chloride, 40-assembly 1#.

[0034] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0035] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0036] It should be noted that in the description of the present invention, the terms "transverse", "longitudinal", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate the orientation or position relationship based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second" and the like are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0037] The invention provides a highly impact-resistant and anti-falling polycrystalline diamond carbide pick head.

[0038] Reference Figure 1 , Figure 2 and Figure 4 The present invention proposes a first embodiment of a high impact resistance and anti-shedding polycrystalline diamond carbide pick head. In this embodiment, the high impact resistance and anti-shedding polycrystalline diamond carbide pick head comprises a carbide substrate 1 and a polycrystalline diamond layer 2 composited on the head of the carbide substrate 1, wherein:

[0039] The polycrystalline diamond layer 2 has an N-layer structure, N is greater than or equal to 2, the top of the polycrystalline diamond layer 2 is in the shape of a spherical crown, the abdomen of the polycrystalline diamond layer 2 is a spherical surface formed by rotating a circular arc, the top and abdomen of the polycrystalline diamond layer 2 are smoothly transitioned through fillets, and the top spherical surface radius of the polycrystalline diamond layer 2 is less than or equal to the abdomen spherical surface radius;

[0040] The cemented carbide substrate 1 is provided with a top, a middle and a bottom, the top 11 of the cemented carbide substrate 1 is compounded with a polycrystalline diamond layer 2, the middle 12 of the cemented carbide substrate 1 is a truncated cone structure, the bottom 13 of the cemented carbide substrate 1 is a truncated cone structure of at least two layers (in this embodiment, the bottom 13 of the cemented carbide substrate 1 is a two-layer truncated cone structure), and the upper bottom radius of the truncated cone of the middle 12 of the cemented carbide substrate 1 is smaller than the lower bottom radius. The upper bottom radius of each bottom truncated cone of the cemented carbide substrate 1 is larger than the lower bottom radius.

[0041] Specifically, the spherical radius of the top spherical crown structure of the polycrystalline diamond layer 2 is 0.5mm-5mm (in this embodiment, the spherical radius of the top of the polycrystalline diamond layer 2 is 1mm as an example), and the spherical radius of the belly of the polycrystalline diamond layer 2 is 5mm-45mm (in this embodiment, the spherical radius of the belly of the polycrystalline diamond layer 2 is 20mm as an example).

[0042] Specifically, the top 11 of the cemented carbide substrate 1 is a truncated cone structure, the upper bottom surface and the side surface of the truncated cone of the top 11 of the cemented carbide substrate 1 are smoothly transitioned through an arc, and the radius of the upper bottom surface of the truncated cone of the top 11 of the cemented carbide substrate 1 is smaller than the radius of the lower bottom surface.

[0043] Specifically, the angle α1 of the corresponding hypotenuse of the longitudinal section of the top truncated cone of the cemented carbide substrate 1 is 30°-150°, and a convex ridge 111 is provided on the side of the top truncated cone of the cemented carbide substrate 1. The cross section of the convex ridge 111 is an arc (semicircular or partially circular), and the edge of the convex ridge 111 smoothly transitions with the side of the truncated cone. The number of convex ridges 111 is greater than or equal to one.

[0044] The cross-sectional arc radius of the convex rib 111 is 0.1 mm-3 mm, and the protrusion height of the convex rib 111 perpendicular to the side of the truncated cone is 0.1 mm-3 mm. The convex rib 111 is intermittent or continuous ring-shaped.

[0045] Specifically, the lower bottom surface of the top truncated cone of the cemented carbide substrate 1 and the upper bottom surface of the middle truncated cone of the cemented carbide substrate 1 are in the same plane, and the radius of the lower bottom surface of the top truncated cone is less than or equal to the radius of the upper bottom surface of the middle truncated cone; the bevel angle α2 corresponding to the longitudinal section of the middle truncated cone of the cemented carbide substrate 1 is 0.5°-45°. The bevel angle α3 corresponding to the longitudinal section of the first bottom truncated cone 131 of the cemented carbide substrate 1 is 90°-180°, and the bevel angle α4 corresponding to the longitudinal section of the second bottom truncated cone 132 is between 10°-120°.

[0046] In this embodiment, the thickness of the polycrystalline diamond layer 2 is greater than or equal to 2 mm.

[0047] The polycrystalline diamond layer 2 is formed by sintering a mixture of micron and / or nanometer-sized diamond, tungsten carbide, cobalt, tungsten and nickel, wherein the average particle size of the powder in the Nth layer is greater than or equal to the N-1th layer, and the percentage of diamond powder in the powder in the Nth layer is less than or equal to the N-1th layer.

[0048] The tops of the 2nd to Nth layers of the polycrystalline diamond layer 2 are all circular platforms 2011 (the circular platform 2011 refers to a platform formed by a linear rotation), and the abdomens of the 2nd to Nth layers of the polycrystalline diamond layer 2 are all spherical surfaces formed by a circular arc rotation. The tops and abdomens of the 2nd to Nth layers of the polycrystalline diamond layer 2 are smoothly transitioned through fillets, the radius of the circular platform 2011 on the top of the N-1th layer is less than or equal to that of the Nth layer, and the radius of the spherical surface of the abdomen of the Nth layer is greater than or equal to the radius of the spherical surface of the abdomen of the N-1th layer.

[0049] In this embodiment, the structure of the cemented carbide substrate 1 of the diamond tooth head is as follows: Figure 1 and Figure 2 As shown, the top 11 truncated cone of the cemented carbide substrate 1 has an upper bottom radius of 3mm and a lower bottom radius of 15mm. There are two ridges 111 on the side of the top truncated cone. The cross section of the ridge 111 is semicircular with a radius of 0.5mm. The edge of the ridge 111 smoothly transitions with the side of the truncated cone. The protrusion height of the two ridges 111 perpendicular to the side of the truncated cone is 0.5mm. The radius R6 of the bottom surface of the middle truncated cone 12 of the cemented carbide substrate 1 is 15.97mm. The angle α1 of the two hypotenuses of the longitudinal section of the top truncated cone is 85°. The angle α2 of the two hypotenuses 423 of the longitudinal section of the middle truncated cone is 5°. The angle α4 of the two hypotenuses of the longitudinal section of the first bottom truncated cone 131 is 90°. The angle α3 of the two hypotenuses of the longitudinal section of the second bottom truncated cone 132 is 140°.

[0050] The polycrystalline diamond layer 2 has two layers, namely the first polycrystalline diamond layer 200 and the second polycrystalline diamond layer 201. The top of the first polycrystalline diamond layer 200 is in the shape of a spherical crown, with a spherical radius of 1 mm, and the abdomen is a spherical surface formed by a circular arc rotation, with a spherical radius of 20 mm. The top of the second polycrystalline diamond layer 201 is a circular platform 2011 with a radius of 2.0 mm, and the abdomen is a spherical surface formed by a circular arc rotation, with a spherical radius of 21 mm. The edge of the circular platform 2011 and the top of the abdomen of the polycrystalline diamond layer 2 are smoothly transitioned through a fillet R1.5 mm.

[0051] The preparation method of the high impact resistance and fall-off resistance polycrystalline diamond carbide pick head is as follows.

[0052] The cemented carbide substrate 1 contains 10wt.% cobalt and 90wt.% WC, wherein the WC grains are about 5 microns. The cemented carbide is processed by cylindrical grinding to the required size, flat grinding to the required size, and a universal cylindrical grinder to process the formed conical surface to the required size. Sandblasting, ultrasonic cleaning for 30 minutes, and then drying for use.

[0053] The first layer 200 of the polycrystalline diamond layer contains 75wt.% of diamond powder, with a particle size of 4-15 microns, 14wt.% of WC powder, 0.5 microns of WC powder particle size, 10wt.% of Co powder, 0.3 microns of Co powder particle size, and 1wt.% of W powder. The second layer 201 of the polycrystalline diamond layer contains 55wt.% of diamond powder, with a particle size of 15-50 microns, 35wt.% of WC powder, 0.5 microns of WC powder particle size, 4wt.% of Co powder, 0.3 microns of Co powder particle size, 5wt.% of W powder, 0.3 microns of W powder particle size, and 1wt.% of Ni powder, with a particle size of 0.5 microns. The above two kinds of powders are weighed separately, anhydrous ethanol is added, mixed on a planetary ball mill for 30 minutes, fully mixed, and dried for use.

[0054] The processed diamond layer mixed powder is weighed and placed into a metal cup, compacted and shaped to prepare a first layer of powder. The processed diamond layer mixed powder is then weighed and placed into a metal cup containing the first layer of powder, and compacted and shaped to prepare a second layer of powder.

[0055] The processed cemented carbide substrate 1 is placed on the two layers of formed diamond powder, wherein the top part contacts the diamond mixed powder. The cemented carbide substrate 1, the diamond mixed powder and the metal cup are compacted to form an assembly 1#.

[0056] The compacted assembly 1# was subjected to high temperature vacuum purification treatment at a temperature of 550°C and a vacuum value of 10 -3 Pa;

[0057] After high temperature purification, install the assembly 1# into Figure 4 The special synthetic mold shown here constitutes a complete diamond composite pick head synthetic block assembly 2#.

[0058] The above assembly 2# was sintered on a domestic six-sided hydraulic press at about 1500°C and 7.0GPa under high temperature and high pressure conditions. The high temperature and high pressure sintering time was about 35 minutes to obtain a diamond tooth head blank.

[0059] The diamond tooth head blank is processed into a finished diamond tooth head with required external dimensions by diamond end face sandblasting, external cylindrical grinding, and hard alloy end face plane and chamfer grinding.

[0060] The diamond tooth head of Example 1 was flame brazed to the test fixture using Ag40Cu19Zn21Cd welding wire at a welding temperature of about 620°, and a pendulum impact test was conducted in the forward direction. The impact block was made of HRC58.5 Cr12MoV. Under an impact energy of 150J, the average number of impact resistances reached 400 times. After the impact test, the diamond tooth head and the test fixture were firmly welded, and the tooth head was not loose.

[0061] The present invention further provides a second embodiment of a highly impact-resistant and anti-falling polycrystalline diamond carbide pick head.

[0062] Reference Figure 3 , the present embodiment is different from the first embodiment described above in that the polycrystalline diamond layer 2 has a three-layer structure, namely, the first polycrystalline diamond layer 200, the second polycrystalline diamond layer 201 and the third polycrystalline diamond layer 202. The top of the first polycrystalline diamond layer 200 is a spherical crown, the spherical radius is 1.0 mm, and the abdominal spherical radius is 20 mm. The top of the second polycrystalline diamond layer 201 is a circular platform 2011, the radius is 1.5 mm, the abdominal spherical radius is 21 mm, and the edge of the circular platform 2011 and the abdominal top of the polycrystalline diamond layer 201 are smoothly transitioned through a fillet R2.0 mm. The top of the third polycrystalline diamond layer 202 is a circular platform 2011, the radius is 2.0 mm, the abdominal spherical radius is 22 mm, and the edge of the circular platform 2011 and the abdominal top of the polycrystalline diamond layer 202 are smoothly transitioned through a fillet R1.5 mm.

[0063] The preparation method of the high impact resistance and fall-off resistance polycrystalline diamond carbide pick head is as follows.

[0064] The cemented carbide substrate 1 contains 13wt.% cobalt and 87wt.% WC, and the WC grains are about 3 microns. The cemented carbide is ground to the required size by cylindrical grinding, flat ground to the required size, and formed into a cone surface by a universal cylindrical grinder to the required size. Sandblasting, ultrasonic cleaning for 30 minutes, and then drying for use.

[0065] The first polycrystalline diamond layer 200 contains 75wt.% of diamond powder, with a particle size of 4-15 microns, 14wt.% of WC powder, with a particle size of 0.5 microns, 10wt.% of Co powder, with a particle size of 0.3 microns, and 1wt.% of W powder. The second polycrystalline diamond layer 201 contains 65wt.% of diamond powder, with a particle size of 10-35 microns, 24wt.% of WC powder, with a particle size of 0.5 microns, 8wt.% of Co powder, with a particle size of 0.3 microns, and 3wt.% of W powder, with a particle size of 0.3 microns. The third layer 202 of the polycrystalline diamond layer contains 55wt.% of diamond powder, with a particle size of 15-50 microns, 35wt.% of WC powder, with a particle size of 0.5 microns, 4wt.% of Co powder, with a particle size of 0.3 microns, 5wt.% of W powder, with a particle size of 0.3 microns, and 1wt.% of Ni powder, with a particle size of 0.5 microns. The above three kinds of powders are weighed separately, anhydrous ethanol is added, and the materials are mixed on a planetary ball mill for 30 minutes, fully mixed, and dried for use.

[0066] The treated diamond layer mixed powder is weighed and loaded into a metal cup, compacted and molded to prepare the first layer of powder, and then the treated diamond layer mixed powder is weighed and loaded into a metal cup, compacted and molded to prepare the second layer of powder, and then the treated diamond layer mixed powder is weighed and loaded into a metal cup, compacted and molded to prepare the third layer of powder. The rest of the preparation and processing methods are the same as in Example 1.

[0067] The diamond tooth head of Example 2 was flame brazed to the test fixture using Ag40Cu19Zn21Cd welding wire at a welding temperature of about 620°, and subjected to a pendulum impact test in the forward direction. The impact block was made of HRC58.5 Cr12MoV, and the average number of impact resistances reached 500 times at an impact energy of 150J. After the impact test, the diamond tooth head and the test fixture were firmly welded, and the tooth head was not loose.

[0068] The highly impact-resistant and anti-falling polycrystalline diamond carbide pick head proposed by the present invention has the following beneficial effects:

[0069] 1. By setting a transition layer structure with multiple layers of composition and structure on the diamond layer of the diamond pick, especially setting a multi-layer and thickened transition layer structure on the top of the pick, a smooth transition of elastic modulus and thermal expansion coefficient between the diamond surface layer, especially the tooth head, and the cemented carbide layer is effectively achieved, so that the overall impact strength of the composite pick is greatly enhanced;

[0070] 2. By improving the central welding part of the diamond tooth head from a cylindrical structure to a truncated cone structure, and the radius of the upper bottom surface of the central truncated cone is smaller than the radius of the lower bottom surface, this structure enhances the welding firmness of the tooth head in the tooth hole of the pick, and can effectively reduce the risk of the tooth head falling off under high-frequency external force impact during excavation and milling, and effectively improve the high efficiency and low cost advantages of diamond picks in engineering construction.

[0071] The present invention further provides a method for manufacturing a highly impact-resistant and anti-shedding polycrystalline diamond carbide pick head.

[0072] Reference Figure 5 In this embodiment, a method for manufacturing a highly impact-resistant and anti-shedding polycrystalline diamond carbide pick head comprises the following steps:

[0073] The top of the cemented carbide substrate is sandblasted, ultrasonically cleaned, and dried for later use;

[0074] The powders used for different layers of the polycrystalline diamond layer are mixed separately, and the mixed powders are weighed and loaded into a metal cup for compaction and molding, and each powder layer is prepared by molding from the outside to the inside;

[0075] The formed diamond layer N powder is placed on the processed cemented carbide substrate, and the cemented carbide substrate, the diamond mixed powder and the metal cup are compacted to form a composite mold assembly 1#;

[0076] The compacted assembly 1# is subjected to high temperature vacuum purification treatment;

[0077] The assembly 1# after high temperature purification treatment is loaded into the synthetic mold to form a complete diamond tooth head synthetic mold assembly 2#;

[0078] The assembly 2# is sintered on a six-sided hydraulic press at high temperature and high pressure to obtain a diamond tooth head blank;

[0079] The diamond tooth head blank is processed into a finished diamond tooth head with required dimensions through diamond end face sandblasting, external cylindrical grinding, and carbide end face plane and chamfer grinding.

[0080] Specifically, during the high temperature vacuum purification process, the temperature is 500°C-900°C and the vacuum value is 10 -2 Pa-10 -4 Pa; when sintered at high temperature and high pressure, when placed in the pressure chamber of a six-sided hydraulic press, the temperature is set to 1300℃-1700℃ and the pressure is set to 4.5GPa-8.5GPa.

[0081] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing a highly impact-resistant and anti-shedding polycrystalline diamond carbide pick head, characterized in that: The highly impact-resistant and anti-falling polycrystalline diamond cemented carbide pick head comprises a cemented carbide matrix and a polycrystalline diamond layer compounded on the head of the cemented carbide matrix, wherein: The polycrystalline diamond layer has an N-layer structure, N is greater than or equal to 2, the top of the polycrystalline diamond layer is in the shape of a spherical crown, the abdomen of the polycrystalline diamond layer is a spherical surface formed by rotating a circular arc, the top and abdomen of the polycrystalline diamond layer are smoothly transitioned through fillets, and the top spherical surface radius of the polycrystalline diamond layer is less than or equal to the abdomen spherical surface radius; The cemented carbide substrate is provided with a top, a middle and a bottom, the top of the cemented carbide substrate is compounded with a polycrystalline diamond layer, the middle of the cemented carbide substrate is a truncated cone structure, the bottom of the cemented carbide substrate is a truncated cone structure of at least two layers, and the upper bottom radius of the middle truncated cone of the cemented carbide substrate is smaller than the lower bottom radius; The top of the cemented carbide substrate is a truncated cone structure, the bottom surface and the side surface of the top truncated cone of the cemented carbide substrate are smoothly transitioned through an arc, and the bottom surface radius of the top truncated cone of the cemented carbide substrate is smaller than the bottom surface radius; The angle of the corresponding hypotenuse of the longitudinal section of the top cone of the cemented carbide substrate is 30°-150°, and a convex ridge is provided on the side of the top cone of the cemented carbide substrate. The cross section of the convex ridge is an arc shape, and the edge of the convex ridge smoothly transitions with the side of the cone. The convex ridge is intermittent or continuous ring-shaped; The tops of the second to Nth layers of the polycrystalline diamond layer are all circular platforms, the abdomens of the second to Nth layers of the polycrystalline diamond layer are all spherical surfaces formed by a circle rotating one circle, the tops and abdomens of the second to Nth layers of the polycrystalline diamond layer are smoothly transitioned through fillets, the radius of the circular platform on the top of the N-1th layer is less than or equal to that of the Nth layer, and the radius of the spherical surface of the abdomen of the Nth layer is greater than or equal to the radius of the spherical surface of the abdomen of the N-1th layer; The spherical surface radius of the spherical cap structure at the top of the polycrystalline diamond layer is 0.5mm-5mm, and the spherical surface radius of the abdomen of the polycrystalline diamond layer is 5mm-45mm; The arc radius of the convex ridge is 0.1mm-3mm, and the protrusion height of the convex ridge perpendicular to the side of the truncated cone is 0.1mm-3mm; The lower bottom surface of the top truncated cone of the cemented carbide substrate and the upper bottom surface of the middle truncated cone are in the same plane, and the radius of the lower bottom surface of the top truncated cone is less than or equal to the radius of the upper bottom surface of the middle truncated cone; the corresponding bevel angle of the longitudinal section of the middle truncated cone of the cemented carbide substrate is 0.5°-45°; The thickness of the polycrystalline diamond layer is greater than or equal to 2 mm; the polycrystalline diamond layer is formed by mixing and sintering micron and / or nanometer-sized diamond, tungsten carbide, cobalt, tungsten, and nickel, wherein the average particle size value of the powder material in the Nth layer is greater than or equal to the N-1th layer, and the percentage value of the diamond powder content in the powder material in the Nth layer is less than or equal to the N-1th layer; The preparation method comprises the following steps: The top of the cemented carbide substrate is sandblasted, ultrasonically cleaned, and dried for later use; The powders used for different layers of the polycrystalline diamond layer are mixed separately, and the mixed powders are weighed and put into a metal cup for compaction and molding, and each powder layer is prepared by molding from the outside to the inside; The formed diamond layer N powder is placed on the processed cemented carbide substrate, and the cemented carbide substrate, the diamond mixed powder and the metal cup are compacted to form a composite mold assembly 1#; The compacted assembly 1# is subjected to high temperature vacuum purification treatment; The assembly 1# after high temperature purification treatment is loaded into the synthetic mold to form a complete diamond tooth head synthetic mold assembly 2#; The assembly 2# is sintered on a six-sided hydraulic press at high temperature and high pressure to obtain a diamond tooth head blank; The diamond tooth head blank is processed into a finished diamond tooth head with required dimensions through diamond end face sandblasting, external cylindrical grinding, and carbide end face plane and chamfer grinding.

2. The method for preparing a highly impact-resistant and anti-shedding polycrystalline diamond carbide pick head according to claim 1, characterized in that: During high temperature vacuum purification, the temperature is 500℃-900℃ and the vacuum value is 10 -2 Pa-10 -4 Pa; when sintered at high temperature and high pressure, when placed in the pressure chamber of a six-sided hydraulic press, the temperature is set to 1300℃-1700℃ and the pressure is set to 4.5GPa-8.5GPa.

Images