A cemented carbide grinding shoe, its preparation method and application

Abstract

The present application relates to the technical field of grinding shoes, in particular to a hard alloy grinding shoe, a preparation method and application thereof. The hard alloy grinding shoe comprises a steel base body and a grinding layer. The grinding layer comprises a plurality of hard alloy studs. One end of the hard alloy stud is a three-dimensional structure with hard alloy particles arranged inside. The other end of the hard alloy stud is a stud structure. Each stud structure extends into the steel base body, so that the steel base body and the grinding layer are connected through threads. The grinding layer further comprises a copper-based matrix alloy arranged between the hard alloy studs. The present application can solve the problem of excessive stress caused by uneven spacing between hard alloy particles due to the aggregation of hard alloy particles during the welding process of traditional grinding shoes, thereby improving the quality and service life of the grinding shoe.

Description

Technical Field

[0001] This invention relates to the field of shoe polishing technology, and more specifically, to a cemented carbide shoe polishing shoe, its preparation method, and its application. Background Technology

[0002] Grinding shoes are a type of downhole accident handling tool. During drilling or oil production operations, it's common for downhole drill strings to become stuck, disengaged, or broken, and for surface debris such as metal fragments, cement, or even drill bit cones and carbide cones to fall into the well – a phenomenon commonly known as "fallen fish." Fallen fish should be retrieved promptly, otherwise normal operations will be disrupted. When retrieval tools are ineffective in dealing with stuck drill strings or when fallen fish cannot be retrieved intact, grinding shoes must be lowered to grind the fallen fish into fragments, which are then carried out of the wellbore using drilling fluid circulation.

[0003] The current welding process for grinding shoes involves using an oxy-acetylene flame to weld YD-type cemented carbide welding rods onto the tool substrate. The YD-type cemented carbide welding rods are composed of granular cemented carbide and a copper-based matrix alloy. The density of the cemented carbide particles is 9.7–15.3 g / cm³. 3 The density of the copper-based matrix alloy is 8.5–8.9 g / cm³. 3 During flame brazing, the copper-based matrix alloy melts, and the density of the cemented carbide is much greater than that of the matrix alloy. When brazing cemented carbide grinding shoes, the cemented carbide particles are prone to precipitate and aggregate, resulting in poor grinding shoe quality and short service life.

[0004] Patent CN115922146A discloses a particle-reinforced solder paste, which includes a brazing filler metal, a flux, and granular cemented carbide. After soldering, the cemented carbide particles are uniformly dispersed in the weld seam, forming an effective bond with the cemented carbide workpiece and the brazing filler metal. However, the role of the cemented carbide particles in the weld seam is to improve the weld strength.

[0005] Patent CN115898395A discloses a method for preparing a serrated polycrystalline diamond composite sheet, comprising the following steps: high-temperature and high-pressure sintering of diamond powder raw materials and a cemented carbide matrix to obtain a PDC composite sheet with a sintered bond between a polycrystalline diamond layer and a cemented carbide layer; machining an annular groove on the cemented carbide end face of the PDC composite sheet, and then compacting the powder forming the intermediate transition layer inside the annular groove; immersing the polycrystalline diamond layer of the PDC composite sheet in liquid metal, and then bringing a steel matrix close to the cemented carbide end face of the PDC composite sheet under high-speed rotation, pressing and maintaining the clamping force; when solder flows in the annular groove, stopping the rotation, and continuing to maintain the clamping force between the steel matrix and the PDC composite sheet, thus obtaining the serrated polycrystalline diamond composite sheet. It uses cemented carbide particles, steel matrix powder, and copper-based solder powder as brazing materials for the intermediate transition layer, achieving friction brazing connection between the cemented carbide layer and the steel matrix layer. This joining process differs from both brazing and friction welding. It primarily relies on frictional heat to melt the copper-based brazing alloy powder in the intermediate transition layer into a molten brazing alloy. This molten brazing alloy then encapsulates the cemented carbide particles and steel matrix particles, which act as a reinforcing buffer phase, forming the intermediate transition layer. This layer buffers the residual stress between the steel matrix and the cemented carbide, while also enhancing the interfacial bonding strength. However, this method is not suitable for manufacturing grinding shoes.

[0006] In view of this, the present invention is hereby proposed. Summary of the Invention

[0007] The primary objective of this invention is to provide a carbide grinding shoe that, by incorporating a plurality of carbide studs, improves the quality and service life of the grinding shoe. This solves the problem of excessive stress caused by the aggregation of carbide particles during the welding process in traditional grinding shoes, resulting in uneven spacing between the particles.

[0008] The second objective of this invention is to provide a method for preparing a cemented carbide grinding shoe, wherein the cemented carbide particles prepared by this method are uniformly distributed, the stress between the steel matrix and the cemented carbide particles is small, and the service life of the cemented carbide grinding shoe is long.

[0009] A third objective of this invention is to provide a cemented carbide grinding shoe for use in drilling and well workover, the cemented carbide grinding shoe having a long service life.

[0010] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0011] This invention provides a cemented carbide grinding shoe, comprising a steel substrate and a grinding layer;

[0012] The grinding layer includes a plurality of cemented carbide studs. One end of each cemented carbide stud has a three-dimensional structure with cemented carbide particles inside, and the other end of each cemented carbide stud has a stud structure. Each stud structure extends into the steel substrate, so that the steel substrate and the grinding layer are connected by threads.

[0013] The grinding layer also includes a copper-based matrix alloy disposed between each of the cemented carbide studs.

[0014] This invention further provides a method for preparing the above-mentioned cemented carbide grinding shoe, comprising the following steps:

[0015] Several cemented carbide sleeves are obtained, one end of which is a three-dimensional structure with a blind hole and the other end is a stud structure; cemented carbide particles are inserted into the blind hole, and solder paste is added into the blind hole to weld and fix the cemented carbide particles to obtain cemented carbide studs.

[0016] A steel substrate with several threaded holes is obtained, and the carbide stud is screwed into the threaded holes;

[0017] The copper-based matrix alloy is filled into the gaps between the cemented carbide studs by welding, and the cemented carbide grinding shoe is obtained after cooling.

[0018] The present invention also provides the application of the above-mentioned cemented carbide grinding shoes in drilling and well workover.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] (1) The carbide grinding shoe provided by the present invention can solve the problem of excessive stress caused by the uneven spacing between carbide particles due to the precipitation and aggregation of carbide particles during the welding process of traditional grinding shoes by setting a number of carbide studs, thereby improving the quality and service life of the grinding shoe.

[0021] (2) The cemented carbide grinding shoe provided by the present invention can achieve a stable connection between the cemented carbide particles and the three-dimensional structure by filling the space between the cemented carbide particles and the three-dimensional structure with brazing alloy and cemented carbide, and the cemented carbide particles are not easy to fall off; in addition, by using brazing alloy with a high coefficient of linear expansion and cemented carbide powder with a low coefficient of linear expansion to form a composite material with a coefficient of linear expansion similar to that of the steel matrix, the stress formed at the interface between the cemented carbide particles and the steel matrix after welding can be reduced, thereby further improving the service life of the grinding shoe.

[0022] (3) The cemented carbide grinding shoe provided by the present invention uses a brazing alloy with a low melting temperature to braze cemented carbide particles. After solidification, the interface stress between the cemented carbide particles and the brazing alloy is small, and the cemented carbide particles are not easy to break or fall off during the grinding process.

[0023] (4) The carbide grinding shoe provided by the present invention uses several carbide studs in conjunction with high-efficiency MIG welding, which can alleviate the excessive stress caused by the uneven spacing between carbide particles, further improve the quality of the grinding shoe, extend its service life, and increase production efficiency. At the same time, the heat generated by MIG welding is conducted to the brazing alloy and carbide by the carbide studs, which can relieve the interfacial stress between the carbide particles and the brazing alloy. Attached Figure Description

[0024] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of the carbide grinding shoe provided by the present invention;

[0026] Figure 2 The right view of the carbide grinding shoe provided by the present invention;

[0027] Figure 3 A schematic diagram of the structure of the cemented carbide sleeve provided by the present invention. Detailed Implementation

[0028] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0029] In a first aspect, the present invention provides a cemented carbide grinding shoe, see [link to previous article]. Figure 1 As shown, the carbide grinding shoe includes a steel substrate and a grinding layer connected to one end face of the steel substrate.

[0030] like Figure 1 and Figure 2As shown, the grinding layer includes a plurality of carbide studs. One end of each carbide stud has a three-dimensional structure with carbide particles inside. It can be understood that the three-dimensional structure has holes, and the carbide particles are disposed in the holes. Meanwhile, the other end of each carbide stud has a threaded stud structure. Each stud structure extends into the steel substrate, so that the steel substrate and the grinding layer are connected by threads.

[0031] See Figure 2 As shown, the grinding layer also includes a copper-based matrix alloy disposed between each of the cemented carbide studs.

[0032] The present invention provides a cemented carbide grinding shoe with a specific structure. By setting several cemented carbide studs, it solves the problem of excessive stress caused by the aggregation of cemented carbide particles during the welding process in traditional grinding shoes, which leads to uneven spacing between cemented carbide particles. This improves the quality and service life of the grinding shoe.

[0033] In some specific embodiments, the gap between the cemented carbide particles filling the pores of the three-dimensional structure and the three-dimensional structure is a weld, which is obtained by welding a composite material containing brazing alloy and cemented carbide powder.

[0034] The brazing alloy and cemented carbide fill the gaps between the cemented carbide particles and the cemented carbide studs in the three-dimensional structure, so that the cemented carbide particles are firmly fixed in the holes of the three-dimensional structure.

[0035] In some specific implementations, the weld formed by the brazing alloy and cemented carbide is partially or completely covered with cemented carbide particles.

[0036] In the existing technology, an oxy-acetylene flame is used to weld YD type cemented carbide welding rods onto the tool substrate. YD type cemented carbide welding rods are composed of granular cemented carbide and copper-based matrix alloy. However, the linear expansion coefficients of cemented carbide particles and copper-based matrix alloy are quite different. After the copper-based matrix alloy solidifies, large stress is formed between the cemented carbide particles. The cemented carbide particles are prone to breakage and detachment during grinding, resulting in a short service life of the grinding shoe.

[0037] This invention achieves a stable connection between the cemented carbide particles and the three-dimensional structure by filling the space between the cemented carbide particles and the three-dimensional structure with brazing alloy and cemented carbide powder, so that the weld formed by the brazing alloy and cemented carbide powder at least partially covers the cemented carbide particles. This prevents the cemented carbide particles from falling off. Furthermore, by using a brazing alloy with a high coefficient of linear expansion and a cemented carbide with a low coefficient of linear expansion to form a composite material with a coefficient of linear expansion similar to that of the steel matrix, the stress formed at the interface between the cemented carbide particles and the steel matrix after welding can be reduced, thereby improving the service life of the grinding shoe.

[0038] In some specific embodiments, in order to prevent damage to the cemented carbide particles caused by excessively high brazing temperatures, a silver-based brazing alloy with a low melting temperature is used. The brazing alloy comprises the following components by mass percentage: Ag 45%–60%, Cu 20%–28%, Zn 12%–27.5%, and Sn 1.5%–5.5%. Among them, Ag, by mass percentage, includes but is not limited to point values ​​of any one of 45%, 48%, 50%, 53%, 55%, 58%, and 60%, or any range between any two; Cu, by mass percentage, includes but is not limited to point values ​​of any one of 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, and 28%, or any range between any two; Zn, by mass percentage, includes but is not limited to point values ​​of any one of 12%, 14%, 15%, 17%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, and 27.5%, or any range between any two; Sn, by mass percentage, includes but is not limited to point values ​​of any one of 1.5%, 2%, 3%, 4%, 5%, and 5.5%, or any range between any two.

[0039] The brazing alloy with a specific chemical composition provided by this invention has a low melting temperature. When brazing cemented carbide particles with this alloy, the interfacial stress between the cemented carbide particles and the brazing alloy is low after solidification, making the cemented carbide particles less prone to breakage and detachment during grinding. This avoids the adverse effects on the service life of grinding shoes caused by traditional oxy-acetylene flame welding, which involves high brazing temperatures and high stress between the cemented carbide particles and the steel matrix after the copper-based matrix alloy solidifies.

[0040] In some specific embodiments, MIG welding is used to fill the spaces between the copper-based matrix alloys into each of the cemented carbide studs.

[0041] By using several carbide studs in conjunction with high-efficiency MIG welding, the excessive stress caused by uneven spacing between carbide particles can be further alleviated, thereby improving the quality of the grinding shoe, extending its service life, and increasing production efficiency.

[0042] Meanwhile, the heat generated by MIG welding is conducted from the cemented carbide stud to the brazing alloy and cemented carbide, which can alleviate the interfacial stress between the cemented carbide particles and the brazing alloy.

[0043] In some specific embodiments, the three-dimensional structure of the cemented carbide stud and the material of the stud structure include steel.

[0044] In some specific embodiments, a plurality of the cemented carbide studs are arranged in a regular pattern.

[0045] In some specific embodiments, the number of cemented carbide particles in the three-dimensional structure is one or more. "More than" means at least two, but three, four, or five can also be selected.

[0046] In some specific embodiments, the three-dimensional structure includes at least one of cuboid, cube, triangular prism and hexagonal prism, but is not limited thereto.

[0047] In some specific embodiments, in order to further improve the service life of the grinding shoe, the distance between adjacent carbide studs is 2 to 10 mm, including but not limited to any one of 2 mm, 3 mm, 5 mm, 7 mm, 9 mm, and 10 mm, or any range between two of them.

[0048] In some specific embodiments, in order to further improve the service life and grinding efficiency of the grinding shoe, the protrusion height of the carbide particles in the carbide stud is 0.2 to 2 mm, including but not limited to any one of 0.2 mm, 0.5 mm, 0.8 mm, 1 mm, 1.3 mm, 1.5 mm, 1.8 mm, and 2 mm, or any range between two of them.

[0049] Secondly, the present invention provides a method for preparing the above-mentioned cemented carbide grinding shoe, comprising the following steps:

[0050] The material is processed to obtain several cemented carbide sleeves. One end of each cemented carbide sleeve has a three-dimensional structure with a blind hole, and the other end has a stud structure. When the three-dimensional structure is a cuboid or a cube, a structural diagram of the cemented carbide sleeve can be found [link to diagram]. Figure 3 As shown.

[0051] In some specific implementations, the material of the cemented carbide sleeve includes steel.

[0052] Carbide particles are inserted into each of the blind holes, and solder paste is added into the gap between the blind holes and the carbide particles, and then the solder paste is heated and cured.

[0053] In some specific embodiments, the solder paste is in paste form, making it easy to apply into the gaps between blind vias and cemented carbide particles. Specifically, water and / or organic solvents can be added to form a paste.

[0054] After curing, the cemented carbide sleeve is then subjected to induction heating welding to fix the cemented carbide particles onto the cemented carbide sleeve. After the welding is completed and cooled, several cemented carbide studs are obtained.

[0055] In some specific embodiments, the hard alloy sleeve is placed inside the induction coil for induction heating.

[0056] In some specific implementations, brazing alloy wire is used for repair welding during the welding process.

[0057] Then, holes are drilled and tapped on one end face of the columnar steel substrate to form several threaded holes that are clearance-fitted with the carbide studs. Then, the carbide studs are screwed into the threaded holes of the steel substrate to achieve the connection between the carbide studs and the steel substrate.

[0058] Then, through welding, the copper-based matrix alloy is filled into the gaps between each of the cemented carbide studs, and after cooling, a grinding layer is formed to obtain the cemented carbide grinding shoe.

[0059] The cemented carbide particles prepared by this method are uniformly distributed, the stress between the steel matrix and the cemented carbide particles is small, and the service life of the cemented carbide grinding shoes is long.

[0060] In some specific embodiments, the threaded holes on the steel substrate are arranged in a regular pattern.

[0061] In some specific embodiments, the number of blind holes in the three-dimensional structure with blind holes is one or more.

[0062] In some specific embodiments, during the induction heating process, the induction coil completely covers the three-dimensional structure of the hard alloy sleeve.

[0063] In some specific embodiments, the welding method includes MIG welding.

[0064] Among them, MIG welding refers to gas metal inert welding.

[0065] Using a combination of several carbide studs and efficient MIG welding can further extend the service life of the grinding shoe, and this method has high production efficiency.

[0066] In some specific embodiments, the shielding gas used in the MIG welding includes argon.

[0067] In some specific embodiments, the carbide stud is also washed before being screwed into the steel substrate.

[0068] In some specific embodiments, the washing method includes at least one of acid washing, alkaline washing, water washing, and ethanol cleaning.

[0069] In some specific embodiments, the washing method specifically includes: sequentially performing acid washing, alkaline washing, water washing, and ethanol cleaning.

[0070] Pickling can remove the oxide film on the surface of cemented carbide studs; alkaline washing can remove residual acid on the surface of cemented carbide studs; water washing can remove residual alkali on the surface of cemented carbide studs; and ethanol cleaning can remove moisture from the surface of cemented carbide studs (ethanol dehydration principle) to prevent surface oxidation.

[0071] In some specific embodiments, the pickling includes immersing the cemented carbide stud in a sulfuric acid aqueous solution with a mass concentration of 7% to 20% for 5 to 20 seconds.

[0072] In some specific embodiments, the alkaline washing method includes at least one of the following methods (1) to (4): (1) immersing the cemented carbide stud in a 0.5-5 mol / L NaOH solution for 30-90 s; (2) immersing the cemented carbide stud in a 0.5-5 mol / L KOH solution for 30-90 s; (3) immersing the cemented carbide stud in a 0.2-1 mol / L Na2CO3 solution for 30-90 s; (4) immersing the cemented carbide stud in a 0.1-0.5 mol / L NaHCO3 solution for 30-90 s.

[0073] In some specific embodiments, ethanol cleaning includes immersing the cemented carbide stud in 99% pure ethanol for 5 to 20 seconds.

[0074] In some specific embodiments, the pickling is performed when the temperature of the cemented carbide stud drops to 200-300°C.

[0075] In some specific embodiments, the particle size of the cemented carbide particles is 1 to 8 mesh; including but not limited to the point value of any one of 1 mesh, 2 mesh, 3 mesh, 4 mesh, 5 mesh, 6 mesh, 7 mesh, and 8 mesh, or the range value between any two.

[0076] In some specific embodiments, the cemented carbide particles include tungsten-cobalt cemented carbide particles.

[0077] In some specific embodiments, the cemented carbide particles comprise 85% to 94% WC and 6% to 15% Co by mass percentage. The WC percentage by mass percentage includes, but is not limited to, any one of 85%, 87%, 89%, 90%, 92%, and 94%, or a range between any two. The Co percentage by mass percentage includes, but is not limited to, any one of 6%, 8%, 10%, 12%, 14%, and 15%, or a range between any two.

[0078] In some specific embodiments, the solder paste is mainly composed of brazing alloy powder, cemented carbide powder and brazing solvent.

[0079] In some specific embodiments, the brazing solvent comprises at least one of boric acid, boric anhydride, potassium fluoride, sodium fluoride, potassium fluoroborate, potassium tetraborate, and potassium hydrofluoride.

[0080] In some specific embodiments, the brazing solvent is composed of the following components by mass percentage: 30%–40% boric anhydride, 20%–30% potassium fluoroborate, and the balance being potassium fluoride. The boric anhydride, by mass percentage, includes, but is not limited to, any one of 30%, 32%, 35%, 38%, or 40%, or a range between any two; the potassium fluoroborate, by mass percentage, includes, but is not limited to, any one of 20%, 23%, 25%, 28%, or 30%, or a range between any two; and the balance is potassium fluoride.

[0081] The brazing solvent with the above chemical composition has a good effect on dissolving and destroying the oxide film on the surface of the base material and the brazing filler metal during the brazing of cemented carbide studs. It has good thermal stability, low viscosity, good fluidity, can well wet the base material, reduce the interfacial tension between the liquid brazing filler metal and the base material, and the residue is easy to remove.

[0082] In some specific embodiments, the particle size of the cemented carbide powder is 150 to 200 mesh; including but not limited to the point value of any one of 150 mesh, 160 mesh, 180 mesh, and 200 mesh, or the range between any two.

[0083] In some specific embodiments, the cemented carbide powder includes tungsten-cobalt cemented carbide powder.

[0084] In some specific embodiments, the cemented carbide powder comprises 85% to 94% WC and 6% to 15% Co by mass percentage; wherein, the WC by mass percentage includes, but is not limited to, any one of 85%, 87%, 89%, 90%, 92%, 94% or any range between the two; and the Co by mass percentage includes, but is not limited to, any one of 6%, 8%, 10%, 12%, 14%, 15% or any range between the two.

[0085] In some specific embodiments, the solder paste is cured by heating. The heating temperature is 100-150°C, including but not limited to any one of 100°C, 110°C, 120°C, 130°C, 140°C, and 150°C, or any range between two of them. The heating time is 20-30 minutes, including but not limited to any one of 20 minutes, 22 minutes, 25 minutes, 28 minutes, and 30 minutes, or any range between two of them.

[0086] In some specific embodiments, the cemented carbide sleeve is subjected to induction heating welding to fix the cemented carbide particles. During the induction heating welding process, the temperature of the outer surface of the cemented carbide sleeve is 600-800°C; including but not limited to any one of 600°C, 650°C, 700°C, 750°C, and 800°C, or any range between two of them.

[0087] In some specific embodiments, the copper-based matrix alloy comprises the following components by mass percentage: Cu 20%–60%, Zn 12%–45%, Ni 0%–10%, and Mn 0%–10%; wherein, Cu by mass percentage includes, but is not limited to, any one of 20%, 30%, 40%, 50%, and 60%, or any range between any two; Zn by mass percentage includes, but is not limited to, any one of 12%, 15%, 20%, 25%, 30%, 35%, 40%, and 45%, or any range between any two; Ni includes, but is not limited to, any one of 0%, 1%, 2%, 3%, 5%, 7%, 9%, and 10%, or any range between any two; and Mn includes, but is not limited to, any one of 0%, 1%, 2%, 3%, 5%, 7%, 9%, and 10%, or any range between any two.

[0088] The aforementioned copper-based matrix alloy may contain nickel and manganese, or it may not contain nickel and manganese.

[0089] When nickel and / or manganese are added, nickel can improve the brazing strength, and manganese can improve the wettability of copper-based matrix alloys.

[0090] In some specific embodiments, the melting temperature of the copper-based matrix alloy is 830–955°C; including but not limited to any one of 830°C, 840°C, 850°C, 860°C, 870°C, 880°C, 900°C, 910°C, 920°C, 930°C, 940°C, and 955°C, or a range between any two.

[0091] The copper-based matrix used in this invention has a low melting point, resulting in minimal damage to the cemented carbide particles during welding due to heat conduction. It is also soft and facilitates chip removal during grinding.

[0092] In some specific embodiments, the copper-based matrix alloy is filamentous, and the diameter of the copper-based matrix alloy is 1 to 1.8 mm, including but not limited to any one of 1 mm, 1.2 mm, 1.3 mm, 1.5 mm, 1.6 mm, and 1.8 mm, or a range between any two.

[0093] In some specific embodiments, the solder alloy powder is spherical or near-spherical in shape.

[0094] In some specific embodiments, the particle size of the brazing alloy powder is 100 to 150 mesh, including but not limited to the point value of any one of 100 mesh, 120 mesh, 140 mesh, and 150 mesh, or the range between any two.

[0095] In some specific embodiments, the solder paste comprises the following components by weight percentage: 5%–15% soldering solvent, 10%–15% cemented carbide powder, 30%–50% brazing alloy powder, 15%–25% water, and 5%–10% ethanol.

[0096] Thirdly, the present invention provides the application of the above-mentioned cemented carbide grinding shoes in drilling and well workover.

[0097] The carbide grinding shoe provided by this invention can be used for drilling and well workover, such as grinding and milling metal debris (drill pipe, drill tools, etc.) at the bottom of the well, and has a long service life.

[0098] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0099] Example 1

[0100] The method for preparing carbide grinding shoes provided in this embodiment includes the following steps:

[0101] (1) The steel block is machined to produce several cemented carbide sleeves, wherein one end of the cemented carbide sleeve is a cube structure with a blind hole (the number of blind holes is one), and the other end is a stud structure with threads; wherein the diameter of the blind hole in the cube structure of the cemented carbide sleeve is 5mm, the depth of the blind hole is 3mm, and the side length of the square cross-section of the cube structure is 7mm; the diameter of the stud structure of the cemented carbide sleeve is 4mm.

[0102] (2) Secure the cemented carbide particles into the blind holes of each cemented carbide sleeve; wherein the grade of the cemented carbide particles is YG8 and the particle size is 4 mesh.

[0103] (3) Mix the brazing solvent, cemented carbide powder and brazing alloy powder with alcohol and water to form a paste, and inject the solder paste into the gap between the blind hole and the cemented carbide particles with a syringe. Then place it in a 150°C oven and heat for 20 minutes.

[0104] The solder paste comprises the following components by weight percentage: 40% brazing alloy powder, 10% cemented carbide powder, 15% brazing solvent, 25% water, and 10% ethanol; the brazing solvent is composed of the following components by weight percentage: 35% boron anhydride, 23% potassium fluoroborate, and 42% potassium fluoride; the cemented carbide powder is grade YG11 with a mesh size of 150 mesh; the brazing alloy powder is composed of BAg56CuZnSn (National Standard GB / T10046-2018 for Silver Brazing Alloys), with a mesh size of 100 mesh, and the particle shape of the brazing alloy powder is nearly spherical;

[0105] (4) Place the cemented carbide sleeve obtained in step (3) into the induction coil and heat it until the outer surface temperature of the cemented carbide sleeve is 700℃. When the solder in the blind hole is a bright liquid that wets the cemented carbide particles, use a 1mm diameter brazing alloy wire to repair the solder until the bright liquid solder completely covers and fills the blind hole of the cemented carbide sleeve and the cemented carbide particles are fully wetted. Stop heating to obtain several cemented carbide studs.

[0106] (5) When the temperature of the cemented carbide stud drops to 200℃, it is placed in a 10% sulfuric acid aqueous solution for acid washing for 10s, then placed in a 2mol / L NaOH solution for 50s for alkaline washing, then rinsed with water, and then placed in 99% industrial ethanol for 10s, then taken out and dried for later use.

[0107] (6) Drill and tap a series of holes on one end face of the columnar steel substrate to form a number of regularly arranged threaded holes that are in clearance fit with the cemented carbide stud; then screw the washed cemented carbide stud obtained in step (5) into the threaded hole of the steel substrate through a threaded connection.

[0108] (7) MIG welding is used to fill the gaps between each cemented carbide sleeve with copper-based matrix alloy wire. Argon is used as the shielding gas in MIG welding. The steel substrate is preheated to 200°C and the welding current is 200A. The copper-based matrix alloy wire includes the following components by mass percentage: Cu 55%, Zn 35%, Ni 6% and Mn 4%. The melting temperature of the copper-based matrix alloy wire is 880-920°C and the diameter of the copper-based matrix alloy wire is 1.8mm. After welding and cooling, cemented carbide grinding shoes are obtained.

[0109] The carbide grinding shoe produced by this invention includes a steel substrate and a grinding layer. The grinding layer includes a plurality of regularly arranged carbide studs. One end of each carbide stud has a three-dimensional structure with carbide particles inside, and the other end has a stud structure. Each stud structure extends into the steel substrate, connecting the steel substrate and the grinding layer via threads. The grinding layer also includes a copper-based matrix alloy disposed between the carbide studs. The gap between the carbide particles and the three-dimensional structure is a weld, obtained by welding a composite material containing brazing filler alloy and carbide powder. The protrusion height of the carbide particles is 1.5 mm, and the distance between adjacent carbide studs is 8 mm.

[0110] Example 2

[0111] The preparation method of the carbide grinding shoe provided in this embodiment is basically the same as that in embodiment 1. The difference is that in step (3), the solder paste includes the following components by mass percentage: 45% brazing alloy powder, 15% carbide powder, 10% brazing solvent, 20% water and 10% ethanol.

[0112] Example 3

[0113] The preparation method of the cemented carbide grinding shoe provided in this embodiment is basically the same as that in embodiment 1. The difference is that in step (3), the brazing solvent is composed of the following components in terms of mass percentage: 40% boron anhydride, 30% potassium fluoroborate and 30% potassium fluoride.

[0114] Example 4

[0115] The preparation method of the carbide grinding shoe provided in this embodiment is basically the same as that in embodiment 1. The difference is that in step (7), the copper-based matrix alloy wire includes the following components by mass percentage: Cu 60%, Zn 20%, Ni 10% and Mn 10%.

[0116] Comparative Example 1

[0117] Using YD-5 type cemented carbide welding rods and brazing flux with the same composition as in Example 1, oxy-flame surfacing was performed on a steel substrate of the same size as in Example 1, and the dimensions of the finished product after welding were consistent with those in Example 1.

[0118] Comparative Example 2

[0119] The preparation method of the grinding shoe provided in this comparative example is basically the same as that in Example 1, except that no cemented carbide powder is added in step (3).

[0120] Comparative Example 3

[0121] The preparation method of the polished shoe provided in this comparative example is basically the same as that in Example 1, except that step (7) is not performed.

[0122] Experimental Example

[0123] In the milling process, carbide grinding shoes primarily control the changes in drilling pressure and rotation speed to regulate the milling progress. A milling test bench was constructed to simulate the milling operation of different grinding shoes, and the working efficiency and service life of the carbide grinding shoes prepared in each embodiment and comparative example were tested under the same drilling pressure and rotation speed. Under the same conditions, the feed rate and service life of the carbide grinding shoes are shown in Table 1.

[0124] Table 1. Results of feed rate and service life for various cemented carbide products:

[0125] Group Drilling pressure (KN) Rotational speed (r / min) Footage (m / h) Lifespan (h) Example 1 50 50 2.8 12.3 Example 2 50 50 2.7 11.6 Example 3 50 50 2.8 11.9 Example 4 50 50 2.9 12.1 Comparative Example 1 50 50 2.1 5.8 Comparative Example 2 50 50 2.5 9.7 Comparative Example 3 50 50 1.9 4.5

[0126] As shown in Table 1, the multilayer cemented carbide grinding shoes prepared in each embodiment have high working efficiency and long service life. In contrast, the grinding shoe obtained by the conventional oxy-flame welding method in Comparative Example 1 has a shorter service life.

[0127] Comparative Example 2 showed a significantly reduced service life due to the absence of cemented carbide powder.

[0128] Comparative Example 3, due to the lack of MIG welding, resulted in the copper-based matrix alloy wire being filled into the gaps between each cemented carbide sleeve, leading to a significant reduction in service life.

[0129] Therefore, the carbide grinding shoe provided by the present invention has a long service life.

[0130] Furthermore, this invention further improves the service life of grinding shoes by filling the space between cemented carbide particles and the three-dimensional structure with brazing alloy and cemented carbide powder, and then performing MIG welding.

[0131] Although the present invention has been illustrated and described with specific embodiments, it should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, without departing from the spirit and scope of the present invention; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention; therefore, this means that all such substitutions and modifications that fall within the scope of the present invention are included in the appended claims.

Claims

1. A cemented carbide grinding shoe, characterized in that, Includes a steel substrate and a ground layer; The grinding layer includes a plurality of cemented carbide studs. One end of each cemented carbide stud has a three-dimensional structure with cemented carbide particles inside, and the other end of each cemented carbide stud has a stud structure. Each stud structure extends into the steel substrate, so that the steel substrate and the grinding layer are connected by threads. The grinding layer also includes a copper-based matrix alloy disposed between each of the cemented carbide studs.

2. The carbide grinding shoe according to claim 1, characterized in that, The gap between the cemented carbide particles and the three-dimensional structure is a weld, which is obtained by welding a composite material containing brazing filler alloy and cemented carbide powder.

3. The carbide grinding shoe according to claim 2, characterized in that, The brazing alloy comprises the following components by mass percentage: Ag 45%~60%, Cu 20%~28%, Zn 12%~27.5% and Sn 1.5%~5.5%.

4. The carbide grinding shoe according to claim 1, characterized in that, MIG welding is used to fill the spaces between the carbide studs with the copper-based matrix alloy.

5. The carbide grinding shoe according to claim 1, characterized in that, Includes at least one of the following features (1) to (5): (1) Several of the aforementioned cemented carbide studs are arranged in a regular pattern; (2) The number of cemented carbide particles in the three-dimensional structure is one or more; (3) The three-dimensional structure includes at least one of cuboid, cube, triangular prism and hexagonal prism; (4) The distance between adjacent cemented carbide studs is 2~10mm; (5) The protrusion height of the carbide particles in the carbide stud is 0.2~2mm.

6. The method for preparing the cemented carbide grinding shoe according to any one of claims 1 to 5, characterized in that, Includes the following steps: Several cemented carbide sleeves are obtained, one end of which is a three-dimensional structure with a blind hole and the other end is a stud structure; cemented carbide particles are inserted into the blind hole, and solder paste is added into the blind hole to weld and fix the cemented carbide particles to obtain cemented carbide studs. A steel substrate with several threaded holes is obtained, and the carbide stud is screwed into the threaded holes; The copper-based matrix alloy is filled into the gaps between the cemented carbide studs by welding, and the cemented carbide grinding shoe is obtained after cooling.

7. The method for preparing the cemented carbide grinding shoe according to claim 6, characterized in that, The process of filling the gaps between the carbide studs with copper-based matrix alloy by welding includes MIG welding.

8. The method for preparing the cemented carbide grinding shoe according to claim 7, characterized in that, The shielding gas used in the MIG welding includes argon.

9. The method for preparing the cemented carbide grinding shoe according to claim 6, characterized in that, The carbide stud is also washed before being screwed into the steel substrate.

10. The method for preparing the cemented carbide grinding shoe according to claim 9, characterized in that, The washing method includes at least one of acid washing, alkaline washing, water washing, and ethanol cleaning.

11. The method for preparing the cemented carbide grinding shoe according to claim 10, characterized in that, The washing method specifically includes: sequentially performing acid washing, alkaline washing, water washing, and ethanol cleaning.

12. The method for preparing the cemented carbide grinding shoe according to claim 6, characterized in that, Includes at least one of the following features (1) to (15): (1) The particle size of the cemented carbide particles is 1~8 mesh; (2) The cemented carbide particles include tungsten-cobalt cemented carbide particles; (3) The cemented carbide particles comprise 85% to 94% WC and 6% to 15% Co by mass percentage; (4) The solder paste is mainly composed of brazing alloy powder, hard alloy powder and brazing solvent; (5) The components of the brazing solvent include at least one of boric acid, boric anhydride, potassium fluoride, sodium fluoride, potassium fluoroborate, potassium tetraborate and potassium hydrofluoride; (6) The brazing solvent consists of the following components by mass percentage: Composition: Boric anhydride 30%~40%, potassium fluoroborate 20%~30%, balance potassium fluoride; (7) The particle size of the cemented carbide powder is 150~200 mesh; (8) The cemented carbide powder includes tungsten-cobalt cemented carbide powder; (9) The cemented carbide powder comprises 85% to 94% WC and 6% to 15% Co by mass percentage; (10) The solder paste is cured by heating, wherein the heating temperature is 100~150℃ and the heating time is 20~30min; (11) The cemented carbide sleeve is subjected to induction heating welding to fix the cemented carbide particles. During the induction heating welding process, the temperature of the outer surface of the cemented carbide sleeve is 600~800℃. (12) The copper-based matrix alloy comprises the following components by mass percentage: Cu 20%~60%, Zn 12%~45%, Ni 0%~10% and Mn 0%~10%; (13) The melting temperature of the copper-based matrix alloy is 830~955℃; (14) The copper-based matrix alloy is filamentous and the diameter of the copper-based matrix alloy is 1~1.8mm; (15) The particle size of the brazing alloy powder is 100~150 mesh.

13. The application of the carbide grinding shoe as described in any one of claims 1 to 5 in drilling and well workover.

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