A ceramic reinforced hard alloy sintered welding rod for surface welding of oil and gas workover tools and a manufacturing method thereof

Abstract

The application discloses a ceramic-reinforced hard alloy sintered electrode for surface build-up welding of oil and gas workover tools and a manufacturing method thereof. The electrode is prepared from multi-prism hard alloy particles and soft metal. The multi-prism hard alloy particles utilize the excellent grinding effect of TiB2 and TiC composite ceramic materials at high temperatures to improve the performance of the hard alloy material in the grinding process. The WC, TiC, TiB2, SiC, Mo and Co composite sintered material is used to improve the hardness and grinding performance of the hard alloy material by optimizing the component, content and structure characteristics of the hard alloy material, thereby improving the grinding and milling effect on high-strength steel pipes above P110. The soft metal material is a Cu-Ni-Zn-Mn-Si system powder, which effectively improves the strength and wear resistance of the sintered electrode matrix soft metal itself, solves the problems of weak impact resistance, low hardness and poor cutting performance on P110 high-strength steel of the traditional grinding and milling tool, and improves the grinding and milling effect and working efficiency.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of manufacturing workover tools for the oil and gas industry, and specifically relates to a hard alloy sintered welding rod for surface build-up welding of workover tools and a manufacturing method thereof. BACKGROUND

[0002] P110 high-strength steel pipe column is a steel pipe product used in oil and gas drilling and production, commonly used in wellbore structures of oil and gas wells, used as casing or tubing, with high strength and wear resistance, especially suitable for complex geological conditions and high-pressure oil and gas production operations. Common API P110 materials have strict requirements on chemical composition and mechanical properties to ensure their reliability and safety. P110 high-strength steel pipe column has high yield strength and tensile strength, which enables it to withstand high pressure and large torque, suitable for deep well drilling and high-pressure oil and gas production.

[0003] It should be noted that the materials and processes in the field of drilling and oil and gas production are very strict, and the performance and quality of the steel pipe are directly related to the efficiency and safety of oil and gas production. Therefore, when selecting and using P110 high-strength steel pipe column, relevant standards and specifications must be strictly followed to ensure its quality and reliability. The length and inner and outer surfaces of P110 high-strength steel pipe column must meet the relevant provisions, and the inner surface cannot have defects such as folding, cracking, scarring, etc., and the depth of removal cannot exceed 12.5wt% of the wall thickness, and the outer surface cannot have folding, cracking, delamination, etc. In addition, its chemical composition and physical properties must meet the inspection requirements.

[0004] Therefore, during drilling and oil and gas production, P110 high-strength steel pipe column may be damaged due to impact, wear, corrosion, etc., and timely and efficient milling repair can extend the service life of the steel pipe column, reduce the replacement frequency, and reduce maintenance costs. Damage to the steel pipe column may result in a decrease in its functionality and performance, and damaged steel pipe column may cause safety hazards in operations, and timely and efficient milling repair can eliminate these hazards and enhance the safety of operations, such as unstable connections, size mismatches, etc. Efficient milling repair can restore the original functionality and performance of the steel pipe column to ensure its normal operation in drilling and oil and gas production operations.

[0005] Milling tools are generally used to repair P110 high-strength steel pipe columns. Milling tools are usually made of alloy steel to form the base shape, and then large-grain hard alloy blocks are welded to the surface milling position. The milling function of the milling tool on the damaged pipe column mainly relies on the hard alloy particles welded on the surface. Currently, the hard alloy particles welded on the surface of the milling tool are mainly WC particles, and YD series welding rods are mostly used for welding. However, due to the high brittleness and low hardness of WC particles (approximately HV1350-HV1450), they have weak impact resistance and poor cutting performance for P110 high-strength steel. Especially under local high temperature conditions above 600°C during the milling process, the WC hardness will be greatly reduced, the milling effect will be even lower, and the WC particles are prone to breakage and shedding, seriously affecting the operation efficiency and quality. Summary of the Invention

[0006] In response to the problems existing in the prior art, the present invention provides a ceramic-reinforced hard alloy sintered welding rod for surface welding of oil and gas well repair tools and a manufacturing method thereof, which solves the problems of traditional grinding and milling tools having weak impact resistance, low hardness, and poor cutting performance on P110 high-strength steel, thereby improving the grinding and milling effect and work efficiency.

[0007] The present invention is achieved through the following technical solutions:

[0008] A ceramic-reinforced hard alloy sintered welding rod for surface welding of oil and gas well repair tools, comprising, by weight percentage, 70wt%-85wt% of polygonal hard alloy particles and 15wt%-30wt% of soft metal;

[0009] The polyhedral hard alloy particles include WC: 65wt%-75wt%, TiC: 10wt%-14wt%, TiB2: 5wt%-10wt%, SiC: 1wt%-3wt%, Mo: 0.6wt%-1.5wt%, and the rest is Co;

[0010] The soft metal includes Cu: 55wt%-65wt%, Ni: 15wt%-20wt%, Mn: 1.5wt%-3.0wt%, Si: 0.5wt%-1.0wt%, and the rest is Zn.

[0011] A method for preparing a ceramic-reinforced hard alloy sintered welding rod for surface welding of oil and gas well repair tools, comprising:

[0012] S1, mixing Ti and B4C powders in a certain proportion, and ball milling them in a nitrogen atmosphere to obtain a composite mixed powder;

[0013] S2, using a mold to press the multiphase mixed powder into a block, heating it to 1500±100°C in a vacuum environment, keeping it warm for 5h±1h, then heating it to 1800±100°C, keeping it warm for 1h±0.5h, to obtain a TiC-TiB2 multiphase ceramic material; after crushing the TiC-TiB2 multiphase ceramic material, a TiC-TiB2 multiphase ceramic powder is obtained;

[0014] S3, mixing TiC-TiB2 composite ceramic powder with WC, TiC, SiC, Mo and Co powders in proportion to obtain mixed powder A;

[0015] S4, pressing the mixed powder A into a polygonal mold, and sintering the pressed alloy material at a high temperature to obtain polygonal hard alloy particles;

[0016] S5, after mixing the polygonal hard alloy particles with the soft metal, put them into a mold, heat them to 1100±50℃ in an oxygen-free environment, keep them warm for 10-15 minutes, and slowly cool them in the furnace to obtain ceramic-reinforced hard alloy sintered welding rods for surface welding of oil and gas well repair tools.

[0017] Preferably, the molar ratio of the Ti and B4C powders is 3:1.

[0018] Preferably, the ball milling time is 3h-10h.

[0019] Preferably, the particle size of the TiC-TiB2 composite ceramic powder is 50 mesh to 300 mesh.

[0020] Preferably, the size of the polygonal hard alloy particles is 3 mm to 10 mm.

[0021] Preferably, the specific conditions for sintering the pressed alloy material in S4 under high temperature conditions are: sintering in a vacuum environment, a sintering temperature of 1400±50° C., and a holding time of 8h±1h.

[0022] Preferably, the hardness of the polygonal hard alloy particles is HV1700-HV1900.

[0023] Preferably, the mold in S5 is a tubular mold or an open mold.

[0024] Preferably, the furnace slow cooling in S5 is carried out in an environment of 300±30°C.

[0025] Compared with the prior art, the present invention has the following beneficial technical effects:

[0026] The application provides a ceramic-reinforced hard alloy sintered electrode for surface build-up welding of oil and gas workover tools and a manufacturing method thereof, which improves the milling capacity of the sintered hard alloy electrode when it is used for surface build-up welding of the milling tool by improving the hardness of the hard alloy particles and the soft metal material. The ceramic-reinforced hard alloy sintered electrode is prepared by using multi-prism hard alloy particles and soft metal, the shape and ratio of the multi-prism hard alloy particles are adjusted, the multi-prism hard alloy particles are obtained by mixing WC, TiC, TiB2, SiC, Mo and Co, and have higher hardness and strength. The application improves the performance of the hard alloy material in the grinding process by using the excellent grinding effect of TiB2 and TiC composite ceramic material at high temperature, uses WC, TiC, TiB2, SiC, Mo and Co composite sintered material, optimizes the component, content and structure characteristics of the hard alloy material, improves the hardness and grinding performance of the hard alloy material, and further improves the milling effect on the high-strength steel pipe above P110. The soft metal material uses Cu-Ni-Zn-Mn-Si powder, effectively improves the strength and wear resistance of the sintered electrode body soft metal itself, solves the problems of the traditional milling tool, such as weak impact resistance, low hardness, poor cutting performance on P110 high-strength steel, improves the milling effect and working efficiency.

[0027] Further, the application forms the ceramic-reinforced hard alloy sintered electrode by combining TiC-TiB2 composite ceramic material with traditional WC material, meets the demand of P110 high-strength steel pipe milling operation,

[0028] Further, the TiB2 and TiC composite ceramic material has excellent cutting and grinding performance at high temperature, so that the ceramic-reinforced hard alloy sintered electrode has wide application prospect. DETAILED DESCRIPTION

[0029] The application will be further described in detail below in combination with specific examples, which are an explanation of the application rather than a limitation.

[0030] (1) The sintered electrode of the application is obtained by sintering multi-prism hard alloy particles and soft metal, the proportion of the hard alloy particles is 70-85wt%, and the proportion of the soft metal is 15-30wt%. The components of the multi-prism hard alloy particles are WC: 65-75wt%, TiC: 10-14wt%, TiB2: 5-10wt%, SiC: 1-3wt%, Mo: 0.6-1.5wt%, and the rest is Co. The soft metal is Cu-Ni-Zn-Mn-Si material powder, the components are Cu: 55-65wt%, Ni: 15-20wt%, Mn: 1.5-3.0wt%, Si: 0.5-1.0wt%, and the rest is Zn.

[0031] (2) First, Ti and B4C powders were mixed in a molar ratio of 3:1 and ball-milled in a nitrogen atmosphere for 3 h to 10 h to obtain a composite mixed powder.

[0032] (3) The composite mixed powder is compacted into a block using a mold, heated to 1500±100°C in a vacuum environment, kept warm for 5h±1h, and then heated to 1800±100°C and kept warm for 1h±0.5h to obtain a TiC-TiB2 composite ceramic material.

[0033] (4) Mechanically crushing the TiC-TiB2 composite ceramic material to obtain TiC-TiB2 composite ceramic powder with a particle size of 50 mesh to 300 mesh.

[0034] (5) The TiC-TiB2 composite ceramic powder is uniformly mixed with WC, TiC, SiC and alloy Mo and Co powders in a certain proportion. The mixed powder ratio is WC: 65-75wt%, TiC: 10-14wt%, TiB2: 5-10wt%, SiC: 1-3wt%, Mo: 0.6-1.5wt%, and the rest is Co.

[0035] (6) The powder mixture is pressed into shape using a polygonal mold, and the pressed alloy material is sintered under high temperature conditions to obtain polygonal hard alloy particles.

[0036] (7) It should be further explained that the particle size of the alloy material obtained by pressing is controlled in the range of 3mm-10mm;

[0037] (8) Alloy particles must be sintered in a vacuum environment, with a sintering temperature of 1400 ± 50 °C and a holding time of 8 h ± 1 h;

[0038] (9) After sintering, the hard alloy particles are slowly cooled in the furnace, and the hardness of the alloy particles is HV1700-HV1900.

[0039] (10) Mixing the sintered hard alloy particles with 15-30 wt% of soft metal powder in a ratio of 70-85 wt% and placing the mixture into a tubular mold or an open mold;

[0040] (11) It should be further explained that the soft metal composition is Cu: 55-65wt%, Ni: 15-20wt%, Mn: 1.5-3.0wt%, Si: 0.5-1.0wt%, and the rest is Zn.

[0041] (12) Place the mold in an oxygen-free environment heating furnace and heat it to 1100±50℃, keep it warm for 10-15 minutes, and obtain a hard alloy welding rod.

[0042] (13) Place the sintered hard alloy welding rod in an environment of 300±30℃ and slowly cool it in the furnace to obtain the finished product.

[0043] In order to enable those skilled in the art to better understand the solutions of the present invention, the following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are as follows:

[0044] (1) The sintered welding rod of the present invention is obtained by sintering polygonal hard alloy particles and soft metal, wherein the hard alloy particles account for 70wt% and the soft metal accounts for 30wt%. The polygonal hard alloy particles are composed of WC: 65wt%, TiC: 10wt%, TiB2: 5wt%, SiC: 1wt%, Mo: 0.6wt%, and the remainder is Co. The soft metal is a Cu-Ni-Zn-Mn-Si system material powder, which is composed of Cu: 55wt%, Ni: 15wt%, Mn: 1.5wt%, Si: 0.5wt%, and the remainder is Zn.

[0045] (2) First, Ti and B4C powders were mixed in a molar ratio of 3:1 and ball-milled in a nitrogen atmosphere for 3 h to obtain a composite mixed powder.

[0046] (3) The composite mixed powder was compacted into a block using a mold, heated to 1500°C in a vacuum environment, kept warm for 5 hours, and then heated to 1800°C and kept warm for 1 hour to obtain a TiC-TiB2 composite ceramic material.

[0047] (4) Mechanically crushing the TiC-TiB2 composite ceramic material to obtain TiC-TiB2 composite ceramic powder with a particle size of 50 mesh to 300 mesh.

[0048] (5) TiC-TiB2 composite ceramic powder is uniformly mixed with WC, TiC, SiC and alloy Mo and Co powders in a certain proportion. The mixed powder ratio is WC: 65wt%, TiC: 10wt%, TiB2: 5wt%, SiC: 1wt%, Mo: 0.6wt%, and the rest is Co powder.

[0049] (6) The powder mixture is pressed into shape using a polygonal mold, and the pressed alloy material is sintered under high temperature conditions to obtain polygonal hard alloy particles.

[0050] (7) It should be further explained that the particle size of the alloy material obtained by pressing is controlled in the range of 3mm-5mm;

[0051] (8) Alloy particles must be sintered in a vacuum environment, with a sintering temperature of 1400°C and a holding time of 8 hours;

[0052] (9) After sintering, the hard alloy particles are slowly cooled in the furnace, and the hardness of the alloy particles is HV1700-HV1780.

[0053] (10) The sintered hard alloy particles are mixed evenly with 30 wt % of soft metal powder in a ratio of 70 wt % and loaded into a tubular mold.

[0054] (11) It should be further explained that the soft metal composition is Cu: 55 wt%, Ni: 15 wt%, Mn: 1.5 wt%, Si: 0.5 wt%, and the rest is Zn.

[0055] (12) Place the mold in an oxygen-free environment heating furnace and heat it to 1100°C for 13-15 minutes.

[0056] (13) The sintered hard alloy welding rod is placed in a 300°C environment and slowly cooled in the furnace to obtain a finished product of a ceramic reinforced hard alloy sintered welding rod for welding on the surface of a well repair and milling tool.

[0057] Example 2:

[0058] (1) The sintered welding rod of the present invention is obtained by sintering polygonal hard alloy particles and soft metal, wherein the hard alloy particles account for 85wt% and the soft metal accounts for 15wt%. The polygonal hard alloy particles are composed of WC: 75wt%, TiC: 14wt%, TiB2: 10wt%, SiC: 3wt%, Mo: 1.5wt%, and the remainder is Co. The soft metal is a Cu-Ni-Zn-Mn-Si system material powder, which is composed of Cu: 65wt%, Ni: 20wt%, Mn: 3.0wt%, Si: 1.0wt%, and the remainder is Zn.

[0059] (2) First, Ti and B4C powders were mixed in a molar ratio of 3:1 and ball-milled in a nitrogen atmosphere for 10 h to obtain a composite mixed powder.

[0060] (3) The composite mixed powder was compacted into a block using a mold, heated to 1600°C in a vacuum environment, kept warm for 6 hours, and then heated to 1900°C and kept warm for 1.5 hours to obtain a TiC-TiB2 composite ceramic material.

[0061] (4) Mechanically crushing the TiC-TiB2 composite ceramic material to obtain TiC-TiB2 composite ceramic powder with a particle size of 50 mesh to 300 mesh.

[0062] (5) TiC-TiB2 composite ceramic powder is uniformly mixed with WC, TiC, SiC and alloy Mo and Co powders in a certain proportion. The mixed powder ratio is WC: 75wt%, TiC: 14wt%, TiB2: 10wt%, SiC: 3wt%, Mo: 1.5wt%, and the rest is Co powder.

[0063] (6) The powder mixture is pressed into shape using a polygonal mold, and the pressed alloy material is sintered under high temperature conditions to obtain polygonal hard alloy particles.

[0064] (7) It should be further explained that the particle size of the alloy material obtained by pressing is controlled in the range of 5mm-8mm.

[0065] (8) The sintering of alloy particles needs to be carried out in a vacuum environment, the sintering temperature is 1350℃, and the holding time is 7h.

[0066] (9) After sintering, the hard alloy particles are slowly cooled in the furnace, and the hardness of the alloy particles is HV1820-HV1900.

[0067] (10) The sintered hard alloy particles are mixed evenly with 15 wt % of soft metal powder in a ratio of 85 wt % and loaded into a tubular mold.

[0068] (11) It should be further explained that the soft metal composition is Cu: 65 wt%, Ni: 20 wt%, Mn: 3.0 wt%, Si: 1.0 wt%, and the rest is Zn.

[0069] (12) Place the mold in an oxygen-free environment heating furnace and heat it to 1150°C for 10-12 minutes.

[0070] (13) The sintered hard alloy welding rod is placed in a 330°C environment and slowly cooled in the furnace to obtain a finished product of a ceramic reinforced hard alloy sintered welding rod for welding on the surface of a well repair and milling tool.

[0071] Example 3:

[0072] (1) The sintered welding rod of the present invention is obtained by sintering polygonal hard alloy particles and a soft metal, wherein the hard alloy particles account for 80wt% and the soft metal accounts for 20wt%. The polygonal sintered hard alloy particles are composed of WC: 70wt%, TiC: 12wt%, TiB2: 7wt%, SiC: 2wt%, Mo: 1.0wt%, and the balance is Co. The soft metal is a Cu-Ni-Zn-Mn-Si system material powder, which is composed of Cu: 60wt%, Ni: 18wt%, Mn: 2.0wt%, Si: 0.8wt%, and the balance is Zn.

[0073] (2) First, Ti and B4C powder is mixed in a molar ratio of 3:1, ball-milled in a nitrogen protective atmosphere, and ball-milled for 5 hours to obtain a composite mixed powder.

[0074] (3) The composite mixed powder is compacted into a block using a mold, heated to 1400°C in a vacuum environment, and held for 4 hours, and then heated to 1700°C and held for 0.5 hours to obtain a TiC-TiB2 composite ceramic material.

[0075] (4) The TiC-TiB2 composite ceramic material is mechanically broken to obtain a TiC-TiB2 composite ceramic powder with a particle size of 50-300 mesh.

[0076] (5) The TiC-TiB2 composite ceramic powder is uniformly mixed with WC, TiC, SiC, and alloy Mo and Co powder in a certain proportion, and the mixed powder ratio is WC: 70wt%, TiC: 12wt%, TiB2: 7wt%, SiC: 2wt%, Mo: 1.0wt%, and the rest is Co powder.

[0077] (6) The powder mixture is pressed into a multi-prism mold, and the pressed alloy material is sintered under high temperature conditions to obtain a multi-prism hard alloy particle.

[0078] (7) It should be further noted that the size of the alloy material particles obtained by pressing is controlled in the range of 7-10 mm.

[0079] (8) The sintering of the alloy particles needs to be carried out in a vacuum environment, and the sintering temperature is 1450°C and the holding time is 9 hours.

[0080] (9) The hard alloy particles after sintering are slowly cooled in the furnace, and the hardness of the alloy particles is HV1760-HV1830.

[0081] (10) The sintered hard alloy particles are uniformly mixed with 20wt% of soft metal powder at a proportion of 80wt%, and are loaded into an open mold.

[0082] (11) It should be further noted that the soft metal composition is Cu: 60wt%, Ni: 18wt%, Mn: 2.0wt%, Si: 0.8wt%, and the rest is Zn.

[0083] (12) The mold is placed in an oxygen-free heating furnace and heated to 1050°C and held for 11-14 minutes.

[0084] (13) The sintered hard alloy electrode is placed in a 270°C environment and slowly cooled in the furnace to obtain a ceramic-reinforced hard alloy sintered electrode product for surface welding of a well repair milling tool.

[0085] Example 4:

[0086] (1) The sintering electrode of the present application is obtained by sintering hard alloy particles with multi-prism and soft metal, the proportion of hard alloy particles is 75wt%, and the proportion of soft metal is 25wt%. The composition of the multi-prism sintering hard alloy particles is WC: 65wt%, TiC: 14wt%, TiB2: 10wt%, SiC: 1wt%, Mo: 0.8wt%, and the rest is Co. The soft metal is Cu-Ni-Zn-Mn-Si-Mo system material powder, the composition is Cu: 55wt%, Ni: 20wt%, Mn: 3.0wt%, Si: 0.5wt%, and the rest is Zn.

[0087] (2) First, mix Ti and B4C powders in a molar ratio of 3:1, ball mill in a nitrogen protective atmosphere, ball mill for 7h, and obtain a composite mixed powder.

[0088] (3) The composite mixed powder is compacted into a block by a mold, heated to 1550℃ in a vacuum environment, and kept for 5.5h, then heated to 1860℃, and kept for 1.2h, to obtain a TiC-TiB2 composite ceramic material.

[0089] (4) The TiC-TiB2 composite ceramic material is mechanically broken to obtain a TiC-TiB2 composite ceramic powder with a particle size of 50-300 mesh.

[0090] (5) The TiC-TiB2 composite ceramic powder is uniformly mixed with WC, TiC, SiC, and alloy Mo and Co powders in a certain proportion, and the mixed powder ratio is WC: 65wt%, TiC: 14wt%, TiB2: 10wt%, SiC: 1wt%, Mo: 0.8wt%, and the rest is Co powder.

[0091] (6) The powder mixture is pressed into shape by a multi-prism mold, and the pressed alloy material is sintered at high temperature to obtain hard alloy particles with multi-prism.

[0092] (7) It needs to be further explained that the size of the alloy material particles obtained by pressing is controlled in the range of 5mm-8mm;

[0093] (8) The alloy particle sintering needs to be carried out in a vacuum environment, the sintering temperature is 1420℃, and the holding time is 8.5h;

[0094] (9) The hard alloy particles after sintering are slowly cooled in the furnace, and the hardness of the alloy particles is HV1750-HV1840.

[0095] (10) The sintered hard alloy particles are uniformly mixed with 25wt% of soft metal powder according to the proportion of 75wt%, and are loaded into an open mold.

[0096] (11) It should be further explained that the soft metal composition is Cu: 55 wt%, Ni: 20 wt%, Mn: 3.0 wt%, Si: 0.5 wt%, and the rest is Zn.

[0097] (12) Place the mold in an oxygen-free environment heating furnace and heat it to 1120°C for 12-14 minutes.

[0098] (13) Place the sintered hard alloy welding rod in a 290℃ environment and slowly cool it in the furnace to obtain the finished ceramic reinforced hard alloy sintered welding rod for surface welding of well repair and milling tools.

[0099] Table 1 Welding rod material composition and mass percentage

[0100]

[0101] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0102] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any ordinary technician in this industry can smoothly implement the present invention as shown in the specification and described above. However, any equivalent changes, modifications and evolutions made by technicians familiar with this profession without departing from the scope of the technical solution of the present invention using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the scope of protection of the technical solution of the present invention.

Claims

1. A method for preparing a ceramic-reinforced hard alloy sintered welding rod for surface welding of oil and gas well repair tools, characterized in that: include, S1, mixing Ti and B4C powders in a certain proportion, and ball milling them in a nitrogen atmosphere to obtain a composite mixed powder; S2, using a mold to press the multiphase mixed powder into a block, heating it to 1500±100°C in a vacuum environment, keeping it warm for 5h±1h, then heating it to 1800±100°C, keeping it warm for 1h±0.5h, to obtain a TiC-TiB2 multiphase ceramic material; after crushing the TiC-TiB2 multiphase ceramic material, a TiC-TiB2 multiphase ceramic powder is obtained; S3, mixing TiC-TiB2 composite ceramic powder with WC, TiC, SiC, Mo and Co powders in proportion to obtain mixed powder A; S4, pressing the mixed powder A into a polygonal mold, and sintering the pressed alloy material at a high temperature to obtain polygonal hard alloy particles; The polyhedral hard alloy particles include WC: 65 wt%-75 wt%, TiC: 10 wt%-14 wt%, TiB2: 5 wt%-10 wt%, SiC: 1 wt%-3 wt%, Mo: 0.6 wt%-1.5 wt%, and the rest is Co; S5, according to weight percentage, 70wt%-85wt% of polygonal hard alloy particles and 15wt%-30wt% of soft metal are mixed and loaded into a mold, wherein the soft metal includes Cu: 55wt%-65wt%, Ni: 15wt%-20wt%, Mn: 1.5wt%-3.0wt%, Si: 0.5wt%-1.0wt%, and the rest is Zn. The mixture is heated to 1100±50℃ in an oxygen-free environment, kept warm for 10-15min, and slowly cooled in the furnace to obtain a ceramic reinforced hard alloy sintered welding rod for surface welding of oil and gas well repair tools.

2. The method for preparing a ceramic reinforced hard alloy sintered welding rod for surface welding of oil and gas well repair tools according to claim 1, characterized in that: The molar ratio of the Ti and B4C powders is 3:

1.

3. The method for preparing a ceramic-reinforced hard alloy sintered welding rod for surface welding of oil and gas well repair tools according to claim 1, characterized in that: The ball milling time is 3h-10h.

4. The method for preparing a ceramic-reinforced hard alloy sintered welding rod for surface welding of oil and gas well repair tools according to claim 1, characterized in that: The particle size of the TiC-TiB2 composite ceramic powder is 50 meshes to 300 meshes.

5. The method for preparing a ceramic reinforced hard alloy sintered welding rod for surface welding of oil and gas well repair tools according to claim 1, characterized in that: The size of the polygonal hard alloy particles is 3 mm to 10 mm.

6. The method for preparing a ceramic-reinforced hard alloy sintered welding rod for surface welding of oil and gas well repair tools according to claim 1, characterized in that: The specific conditions for sintering the pressed alloy material in S4 under high temperature conditions are: sintering in a vacuum environment, a sintering temperature of 1400±50° C., and a holding time of 8h±1h.

7. The method for preparing a ceramic reinforced hard alloy sintered welding rod for surface welding of oil and gas well repair tools according to claim 1, characterized in that: The hardness of the polyhedral hard alloy particles is HV1700-HV1900.

8. The method for preparing a ceramic reinforced hard alloy sintered welding rod for surface welding of oil and gas well repair tools according to claim 1, characterized in that: The mold in S5 is a tubular mold or an open mold.

9. The method for preparing a ceramic reinforced hard alloy sintered welding rod for surface welding of oil and gas well repair tools according to claim 1, characterized in that: The furnace slow cooling in S5 is carried out in an environment of 300±30°C.

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