A preparation process for high-strength seamless steel pipe perforation plug

Abstract

The invention relates to the technical field of metal materials, and discloses a preparation process for a high-strength seamless steel pipe perforation plug. A large number of mechanically inhomogeneous bodies of hard particles are distributed on a ceramic reinforcing agent matrix, which generates contact and friction with a crack surface, so that the crack produces a closing effect and passivates the crack tip, thereby reducing the tendency of the plug to crack. The rare earth elements in the fine-grained reinforcing agent are dispersed in the crystal and at the grain boundary, which can effectively hinder the movement of dislocations, adsorb impurity elements such as oxygen and sulfur between crystals, purify the grain boundary and improve the strength of the alloy, and play a "pinning" role on dislocations during deformation. Ion soft nitriding can increase the dislocation density of the material and improve the hardness. The silicon zirconium coating has excellent wear resistance, and magnetron sputtering sputters the silicon zirconium coating material on the surface of the plug substrate to form a silicon zirconium nitride coating with a diffusion barrier effect with the nitrogen element on the substrate surface, thereby improving the strength and wear resistance of the perforation plug material.

Description

Technical Field

[0001] The invention relates to the technical field of metal materials, in particular to a preparation process of a high-strength seamless steel pipe perforation plug. Background Art

[0002] The perforated plug is mainly used for hot-rolled seamless steel pipe to form holes in solid pipe blanks. In the seamless steel pipe penetration process, the plug mold rubs against the hot-rolled metal and moves in reverse at high speed. The surface of the mold is subjected to axial force, radial stress and rotational friction. The actual temperature can reach 900℃. After the penetration, the tip temperature can even reach about 1300℃. In addition, rapid water cooling must be forced during the penetration process to suppress the temperature rise. Under such severe working conditions, the plug is subjected to the composite impact of various compressive stresses, making it easy to be scrapped, such as collapsed nose, sticking steel, and cracking. The quality of the perforated plug and its service life are directly related to the quality and output efficiency of the seamless steel pipe, and thus directly affect the economic benefits. Therefore, the preparation of high-strength and wear-resistant perforated plugs has become an important issue in the production of seamless steel pipes.

[0003] During the perforation process, the plug is subjected to complex stresses such as compressive stress, shear stress, thermal stress, and hot and cold fatigue at the same time, and the top and the front end of the plug are prone to failure; the existing plug is a solid plug, which is heavy and has a high production cost. Under working conditions up to 1200°C, it is subjected to the dual effects of friction and alternating hot and cold. The surface of the plug is prone to cracking due to its low strength, resulting in reduced production efficiency and production quality; Patent No. CN106336238B discloses a high-strength, high-temperature resistant and crack-resistant perforator plug, which is composed of cement, silicate fiber, hydrogen peroxide, aluminum phosphate liquid, an acidic aqueous solution of ethyl orthosilicate, sodium silicate and water. It has the characteristics of small shrinkage, heat resistance and frost resistance, and can avoid cracking when used for a long time. However, it has many added ingredients, the preparation process is relatively complicated, and the mechanical properties and wear resistance of the perforating plug are not significantly improved.

[0004] The piercing machine plug is one of the most consumed key tools in the production of seamless pipes. Its quality and service life directly affect the efficiency and quality of steel pipe production. Since the working conditions of the piercing machine plug are quite harsh, its service life is not high, which affects the production and quality of steel pipes. The present invention first optimizes the composition of the piercing plug, adds ceramic reinforcing agent and fine crystal reinforcing agent to strengthen the matrix of the piercing plug, then adopts ion soft nitriding process for surface treatment to improve the hardness of the diffusion layer, and adopts magnetron sputtering method to deposit silicon zirconium coating, thereby further improving the comprehensive performance of the piercing plug and extending the service life of the piercing plug. Summary of the invention

[0005] The technical problem solved by the invention is to provide a preparation process of a high-strength seamless steel pipe perforation plug, thereby solving the problems of poor strength and poor wear resistance of the existing seamless steel pipe perforation plug.

[0006] The technical solution of the present invention is:

[0007] A high-strength seamless steel pipe perforation plug comprises the following components in percentage by mass: 0.25-0.45% of pure carbon, 0.45-0.65% of pure silicon, 0.15-0.30% of metal manganese, 5.2-7.5% of metal chromium, 0.50-0.95% of metal molybdenum, 0.36-0.58% of metal vanadium, 2.05-2.86% of metal nickel, 0.15-0.25% of metal tungsten, 0.02-0.1% of ceramic reinforcing agent and 0.05-0.25% of fine grain reinforcing agent, and the balance is metal iron.

[0008] The preparation process of high-strength seamless steel pipe piercing plug is carried out according to the following steps:

[0009] (1) Add the above-mentioned components in a medium frequency induction furnace, heat and smelt them, and after they are completely melted, pour them into a preheated stainless steel mold, evacuate them for vacuum casting, and place them in a muffle furnace at 600-750°C for 30-50 minutes after molding. First, quench them at 950-1100°C for 3-6 hours, then temper them at 550-700°C for 1-4 hours, and cool them in the furnace to obtain a seamless steel pipe perforated plug matrix.

[0010] (2) After cleaning and drying the surface of the seamless steel pipe perforated plug substrate, an ion nitrocarburizing process is carried out in a pulse power glow ion nitriding furnace in an argon atmosphere. The seamless steel pipe perforated plug substrate is used as a sample material. The atmosphere in the furnace is ammonia and acetone. The ammonia flow rate is 1-1.5 L / min, the acetone flow rate is 0.01-0.03 L / min, and the insulation time is 8-10 h. After the nitriding is completed, argon is filled and cooled to room temperature to obtain a nitrided seamless steel pipe perforated plug.

[0011] (3) Add zirconium n-propoxide and tetrahydrofuran into a three-necked flask, stir evenly, then add acetylacetone and 1,2-propylene glycol, react at 50-60°C for 2-3h, then add silylene resin, continue to react for 20-40min, concentrate under reduced pressure, perform curing and pyrolysis, and obtain silicon zirconium powder.

[0012] (4) After the nitrided seamless steel pipe perforation head is cleaned and polished with argon ions, the silicon zirconium coating is deposited by radio frequency reactive magnetron sputtering using silicon zirconium powder as a target and the nitrided seamless steel pipe perforation head as a substrate. When sputtering silicon zirconium powder, the working gas pressure is 0.2-0.4 Pa, the sputtering gas is high-purity argon, the sputtering power supply power is 150-250 W, the distance between the substrate and the target is 60-70 mm, and the sputtering time is 40-60 min to obtain a high-strength seamless steel pipe perforation head.

[0013] Furthermore, the ceramic reinforcing agent is any one of titanium carbide, titanium nitride or tungsten carbide.

[0014] Furthermore, the fine grain strengthener is any one of lanthanum oxide, cerium oxide or yttrium oxide.

[0015] Furthermore, in step (1), the smelting temperature is 900-1050°C and the smelting time is 2-4h.

[0016] Furthermore, the ion nitrocarburizing process parameters in step (2) are as follows: working gas pressure of 500-800 Pa, working voltage of 750-850 V, and working temperature of 500-600 °C.

[0017] Furthermore, in step (3), the ratio of zirconium n-propoxide, tetrahydrofuran, acetylacetone, 1,2-propylene glycol, and silylene resin is 1 g: (10-20) mL: (0.4-0.6) g: (0.03-0.05) g: (1-2) g.

[0018] Furthermore, in step (3), the curing temperature is 200-300° C. and the curing time is 2-5 h.

[0019] Furthermore, in step (3), the pyrolysis temperature is 1200-1500° C., and the pyrolysis time is 3-6 h.

[0020] Furthermore, in step (4), the deposition thickness of the silicon zirconium coating is 2-10 μm.

[0021] The beneficial technical effects of the present invention are:

[0022] The present invention optimizes the design of the components of the seamless steel pipe perforation plug, reduces the tendency of the plug to crack by adding a proper amount of ceramic reinforcing agent and fine crystal reinforcing agent, adopts an ion soft nitriding process to nitridize the perforation plug to obtain a nitrided seamless steel pipe perforation plug, and then magnetron sputtering sprays the prepared silicon zirconium powder to obtain a high-strength seamless steel pipe perforation plug, thereby significantly improving the strength and service life of the perforation plug.

[0023] A large number of mechanically inhomogeneous hard particles are distributed on the matrix of the ceramic reinforcement, which has the characteristics of large elastic modulus and small linear expansion coefficient. When the crack expands, it contacts and rubs with the crack surface, so that the crack has a closing effect and passivates the crack tip, reducing the tendency of the plug to crack. The rare earth elements in the fine-grained reinforcement can promote grain nucleation, hinder grain growth, and are dispersed in the crystal and at the grain boundary. The second phase particles formed can effectively hinder the movement of dislocations. In addition, the unique electronic structure of rare earth elements can adsorb impurity elements such as oxygen and sulfur between crystals and form an amorphous structure with them, thereby reducing the concentration of impurity elements between grain boundaries, purifying grain boundaries and improving the strength of the alloy. During the sintering process, rare earth particles can not only promote non-uniform nucleation, but also hinder grain growth as second phase particles, increase the grain boundary bonding strength, and play a "pinning" role on dislocations during deformation, further improving the tensile strength and hardness of the perforation plug.

[0024] Ion soft nitriding is to introduce carbon-containing gases such as acetone into the ion nitriding atmosphere at the same time. On the one hand, nitrogen and carbon atoms penetrate into the surface of the sample to form supersaturated nitrogen and carbon solid solutions, causing austenite lattice distortion, increasing dislocation density and improving hardness; the alloy elements in the perforation plug form nitrides or carbides with nitrogen and carbon, which are dispersed on the surface of the sample, greatly improving the hardness of the perforated layer; the silicon zirconium coating has silicon and chromium with excellent wear resistance, which can be used as a hard phase. During the friction and wear process, it can effectively resist the wear of external abrasive particles. The crack source and crack propagation path of wear microcracks generated during wear are greatly restricted, and the sliding friction and chiseling of some abrasive particles on the coating surface can be converted into rolling, reducing the wear of the coating by the abrasive particles, thereby improving the wear resistance of the perforation plug of the seamless steel pipe; magnetron sputtering sputters the silicon zirconium coating material on the surface of the plug substrate, and forms a layered silicon zirconium nitride coating with diffusion barrier properties with the nitrogen element on the substrate surface, realizing the high strength and wear resistance of the perforation plug material. DETAILED DESCRIPTION

[0025] 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 described embodiments 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 work are within the scope of protection of the present invention.

[0026] Preparation of silylene resin: Under a nitrogen atmosphere, in a four-necked flask equipped with a thermometer and a constant pressure dropping funnel, add 320 mL of tetrahydrofuran and 321 mL of a 2.5 mol / L n-butyl lithium n-hexane solution, stir evenly, add 24 mL of trichloroethylene dropwise, react at -20°C for 2 h, add 100 mL of methyldichlorosilane dropwise, continue to react for 2 h, finally add 5 g of lithium aluminum tetrahydride powder, continue to react for 5 h, filter after the reaction, take the lower layer of clarified filtrate, wash with deionized water, and distill under reduced pressure to obtain silylene resin.

[0027] Example 1

[0028] 0.35% pure carbon, 0.52% pure silicon, 0.25% metallic manganese, 6.30% metallic chromium, 0.76% metallic molybdenum, 0.48% metallic vanadium, 2.43% metallic nickel, 0.20% metallic tungsten, 0.02% titanium carbide and 0.05% lanthanum oxide, the balance being metallic iron, are added into a medium frequency induction furnace, heated to 1000°C and smelted for 3 hours. After being completely melted, they are poured into a preheated stainless steel mold, vacuumed for vacuum casting, and after forming, placed in a muffle furnace at 650°C for insulation for 40 minutes, first quenched at 1050°C for 5 hours, then tempered at 650°C for 2 hours, and cooled with the furnace to obtain a seamless steel pipe perforated plug matrix.

[0029] Example 2

[0030] 0.25% pure carbon, 0.65% pure silicon, 0.15% metallic manganese, 7.50% metallic chromium, 0.50% metallic molybdenum, 0.58% metallic vanadium, 2.05% metallic nickel, 0.25% metallic tungsten, 0.04% titanium nitride and 0.10% cerium oxide, the balance being metallic iron, are added into a medium frequency induction furnace, heated to 1050°C and smelted for 2 hours, and after being completely melted, poured into a preheated stainless steel mold, and vacuumed for vacuum casting. After forming, it is placed in a muffle furnace at 750°C for insulation for 30 minutes, first quenched at 1100°C for 3 hours, then tempered at 700°C for 1 hour, and cooled with the furnace to obtain a seamless steel pipe perforated plug matrix.

[0031] Example 3

[0032] 0.45% pure carbon, 0.45% pure silicon, 0.30% metallic manganese, 5.20% metallic chromium, 0.95% metallic molybdenum, 0.36% metallic vanadium, 2.86% metallic nickel, 0.15% metallic tungsten, 0.06% tungsten carbide and 0.15% yttrium oxide, the balance being metallic iron, are added into a medium frequency induction furnace, heated to 900°C and smelted for 4 hours. After being completely melted, they are poured into a preheated stainless steel mold, vacuumed for vacuum casting, and after forming, they are placed in a muffle furnace at 600°C for insulation for 50 minutes, first quenched at 950°C for 6 hours, then tempered at 550°C for 4 hours, and cooled with the furnace to obtain a seamless steel pipe perforated head matrix.

[0033] Example 4

[0034] 0.42% pure carbon, 0.63% pure silicon, 0.18% metallic manganese, 5.60% metallic chromium, 0.66% metallic molybdenum, 0.51% metallic vanadium, 2.62% metallic nickel, 0.22% metallic tungsten, 0.08% titanium carbide and 0.20% lanthanum oxide, the balance being metallic iron, are added into a medium frequency induction furnace, heated to 950°C and smelted for 4 hours. After being completely melted, they are poured into a preheated stainless steel mold, vacuumed for vacuum casting, and after forming, they are placed in a muffle furnace at 700°C for 45 minutes, first quenched at 1000°C for 4 hours, then tempered at 600°C for 3 hours, and cooled with the furnace to obtain a seamless steel pipe perforated plug matrix.

[0035] Example 5

[0036] 0.28% pure carbon, 0.49% pure silicon, 0.26% metallic manganese, 7.20% metallic chromium, 0.81% metallic molybdenum, 0.42% metallic vanadium, 2.35% metallic nickel, 0.16% metallic tungsten, 0.10% titanium nitride and 0.25% cerium oxide, the balance being metallic iron, are added into a medium frequency induction furnace, heated to 1050°C and smelted for 3 hours. After being completely melted, they are poured into a preheated stainless steel mold, vacuumed for vacuum casting, and after forming, placed in a muffle furnace at 650°C for 35 minutes, first quenched at 1100°C for 5 hours, then tempered at 700°C for 4 hours, and cooled with the furnace to obtain a seamless steel pipe perforated head matrix.

[0037] Comparative Example 1

[0038] 0.35% pure carbon, 0.52% pure silicon, 0.25% metallic manganese, 6.30% metallic chromium, 0.76% metallic molybdenum, 0.48% metallic vanadium, 2.43% metallic nickel, 0.20% metallic tungsten and 0.05% lanthanum oxide, with the balance being metallic iron, are added into a medium frequency induction furnace, heated to 1000°C and smelted for 3 hours. After being completely melted, they are poured into a preheated stainless steel mold, vacuumed for vacuum casting, and after forming, placed in a muffle furnace at 650°C for insulation for 40 minutes, first quenched at 1050°C for 5 hours, then tempered at 650°C for 2 hours, and cooled with the furnace to obtain a seamless steel pipe perforated head matrix.

[0039] Comparative Example 2

[0040] 0.35% pure carbon, 0.52% pure silicon, 0.25% metallic manganese, 6.30% metallic chromium, 0.76% metallic molybdenum, 0.48% metallic vanadium, 2.43% metallic nickel, 0.20% metallic tungsten and 0.02% titanium carbide, the balance being metallic iron, are added into a medium frequency induction furnace, heated to 1000°C and smelted for 3 hours. After being completely melted, they are poured into a preheated stainless steel mold, vacuumed for vacuum casting, and after forming, placed in a muffle furnace at 650°C for insulation for 40 minutes, first quenched at 1050°C for 5 hours, then tempered at 650°C for 2 hours, and cooled with the furnace to obtain a seamless steel pipe perforated plug matrix.

[0041] Table 1 Composition and content of seamless steel pipe piercing plug

[0042]

[0043] Tensile strength test: An electronic universal testing machine was used to test the mechanical properties of the perforated plug. During the test, the tensile speed was 2 mm / min, the paper feed speed was 1 mm / s, and the arithmetic mean of the test results of the three samples was taken as the final test result.

[0044] Vickers hardness test: A microhardness tester is used to measure the Vickers hardness of the perforated head of the seamless steel pipe. The indenter load used is 0.98N and the indenter time is 20s.

[0045] Table 2 Tensile strength and hardness test

[0046]

[0047] It can be seen from the test results in the above table that with the increase of the content of ceramic reinforcement and fine-grained reinforcement, the tensile strength and Vickers hardness of the perforated plug are significantly improved. The tensile strength in Example 4 reaches 1250MPa, and the Vickers hardness reaches 320HV, and the mechanical properties are better. This is because the ceramic reinforcement is a mechanical inhomogeneous body with a large number of hard particles distributed in it, which has the characteristics of a large elastic modulus and a small linear expansion coefficient. While the crack is expanding, it produces contact and friction with the crack surface, causing the crack to have a closing effect and passivate the crack tip, reducing the tendency of the plug to crack; the rare earth elements in the fine-grained reinforcement can promote the grain Nucleation, hindering grain growth, and being dispersed in the crystal and at the grain boundary. The second phase particles formed can effectively hinder the movement of dislocations. In addition, the unique electronic structure of rare earth elements can adsorb impurity elements such as oxygen and sulfur between crystals and form an amorphous structure with them, thereby reducing the concentration of impurity elements between grain boundaries, purifying grain boundaries and improving the strength of the alloy. During the sintering process, rare earth particles can not only promote non-uniform nucleation, but also hinder grain growth as second phase particles, increase the strength of grain boundaries, and play a "pinning" role on dislocations during deformation, further improving the tensile strength and hardness of the piercing head.

[0048] Comparative Example 1 does not contain a ceramic reinforcing agent, and Comparative Example 2 does not contain a fine-grained reinforcing agent. Both have poor mechanical properties, and low tensile properties and Vickers hardness.

[0049] Example 6

[0050] (1) After the surface of the seamless steel pipe perforated plug substrate (prepared in Example 4) was cleaned and dried, an ion nitrocarburizing process was performed in a pulse power glow ion nitriding furnace in an argon atmosphere. The seamless steel pipe perforated plug substrate was used as a sample material. The atmosphere in the furnace was ammonia and acetone. The ammonia flow rate was 1.2 L / min, the acetone flow rate was 0.023 L / min, the working gas pressure was 600 Pa, the working voltage was 800 V, the working temperature was 550°C, and the holding time was 9 h. After the nitriding was completed, argon was filled and cooled to room temperature to obtain a nitrided seamless steel pipe perforated plug.

[0051] (2) Add 10 g of zirconium n-propoxide and 150 mL of tetrahydrofuran into a three-necked flask, stir evenly, then add 5 g of acetylacetone and 0.4 g of 1,2-propylene glycol, react at 55 °C for 2 h, then add 15 g of silylene resin, continue to react for 30 min, concentrate under reduced pressure, first cure at 250 °C for 4 h, then pyrolyze at 1400 °C for 5 h to obtain silicon zirconium powder.

[0052] (3) After the nitrided seamless steel pipe perforation head was cleaned and polished with argon ions, the silicon zirconium coating was deposited by radio frequency reactive magnetron sputtering using silicon zirconium powder as the target and the nitrided seamless steel pipe perforation head as the substrate. When sputtering silicon zirconium powder, the working gas pressure was 0.3 Pa, the sputtering gas was high-purity argon, the sputtering power was 200 W, the distance between the substrate and the target was 65 mm, the sputtering time was 45 min, and the deposition thickness of the silicon zirconium coating was 2 μm, thereby obtaining a high-strength seamless steel pipe perforation head.

[0053] Example 7

[0054] (1) After the surface of the seamless steel pipe perforated plug substrate (prepared in Example 4) was cleaned and dried, an ion nitrocarburizing process was performed in a pulse power glow ion nitriding furnace in an argon atmosphere. The seamless steel pipe perforated plug substrate was used as a sample material. The atmosphere in the furnace was ammonia and acetone. The ammonia flow rate was 1 L / min, the acetone flow rate was 0.01 L / min, the working gas pressure was 500 Pa, the working voltage was 750 V, the working temperature was 500 ° C, and the holding time was 10 h. After the nitriding was completed, argon was filled and cooled to room temperature to obtain a nitrided seamless steel pipe perforated plug.

[0055] (2) Add 10 g of zirconium n-propoxide and 100 mL of tetrahydrofuran into a three-necked flask, stir evenly, then add 4 g of acetylacetone and 0.3 g of 1,2-propylene glycol, react at 50 °C for 3 h, then add 10 g of silylene resin, continue to react for 40 min, concentrate under reduced pressure, first cure at 200 °C for 5 h, then pyrolyze at 1200 °C for 6 h to obtain silicon zirconium powder.

[0056] (3) After the nitrided seamless steel pipe perforation head was cleaned and polished with argon ions, the silicon zirconium coating was deposited by radio frequency reactive magnetron sputtering using silicon zirconium powder as the target and the nitrided seamless steel pipe perforation head as the substrate. When sputtering silicon zirconium powder, the working gas pressure was 0.2 Pa, the sputtering gas was high-purity argon, the sputtering power was 150 W, the distance between the substrate and the target was 60 mm, the sputtering time was 60 min, and the deposition thickness of the silicon zirconium coating was 4 μm, thereby obtaining a high-strength seamless steel pipe perforation head.

[0057] Example 8

[0058] (1) After the surface of the seamless steel pipe perforated plug substrate (prepared in Example 4) was cleaned and dried, an ion nitrocarburizing process was performed in a pulse power glow ion nitriding furnace in an argon atmosphere. The seamless steel pipe perforated plug substrate was used as a sample material. The atmosphere in the furnace was ammonia and acetone. The ammonia flow rate was 1.5 L / min, the acetone flow rate was 0.03 L / min, the working gas pressure was 800 Pa, the working voltage was 850 V, the working temperature was 600 ° C, the holding time was 8 h, and after the nitriding was completed, argon was filled and cooled to room temperature to obtain a nitrided seamless steel pipe perforated plug.

[0059] (2) Add 10 g of zirconium n-propoxide and 200 mL of tetrahydrofuran into a three-necked flask, stir evenly, then add 6 g of acetylacetone and 0.5 g of 1,2-propylene glycol, react at 60 °C for 2 h, then add 20 g of silylene resin, continue to react for 20 min, concentrate under reduced pressure, first cure at 300 °C for 2 h, then pyrolyze at 1500 °C for 3 h to obtain silicon zirconium powder.

[0060] (3) After the nitrided seamless steel pipe perforation head was cleaned and polished with argon ions, the silicon zirconium coating was deposited by radio frequency reactive magnetron sputtering using silicon zirconium powder as the target and the nitrided seamless steel pipe perforation head as the substrate. When sputtering silicon zirconium powder, the working gas pressure was 0.4 Pa, the sputtering gas was high-purity argon, the sputtering power was 250 W, the distance between the substrate and the target was 70 mm, the sputtering time was 40 min, and the deposition thickness of the silicon zirconium coating was 6 μm, thereby obtaining a high-strength seamless steel pipe perforation head.

[0061] Example 9

[0062] (1) After the surface of the seamless steel pipe perforated plug substrate (prepared in Example 4) was cleaned and dried, an ion nitrocarburizing process was performed in a pulse power glow ion nitriding furnace in an argon atmosphere. The seamless steel pipe perforated plug substrate was used as a sample material. The atmosphere in the furnace was ammonia and acetone. The ammonia flow rate was 1.3 L / min, the acetone flow rate was 0.03 L / min, the working gas pressure was 750 Pa, the working voltage was 820 V, the working temperature was 560 ° C, and the holding time was 10 h. After the nitriding was completed, argon was filled and cooled to room temperature to obtain a nitrided seamless steel pipe perforated plug.

[0063] (2) Add 10 g of zirconium n-propoxide and 180 mL of tetrahydrofuran into a three-necked flask, stir evenly, then add 4.5 g of acetylacetone and 0.45 g of 1,2-propylene glycol, react at 60 °C for 3 h, then add 12 g of silylene resin, continue to react for 35 min, concentrate under reduced pressure, first cure at 220 °C for 4 h, then pyrolyze at 1350 °C for 5 h to obtain silicon zirconium powder.

[0064] (3) After the nitrided seamless steel pipe perforation head was cleaned and polished with argon ions, the silicon zirconium coating was deposited by radio frequency reactive magnetron sputtering using silicon zirconium powder as the target and the nitrided seamless steel pipe perforation head as the substrate. When sputtering silicon zirconium powder, the working gas pressure was 0.3 Pa, the sputtering gas was high-purity argon, the sputtering power was 180 W, the distance between the substrate and the target was 65 mm, the sputtering time was 45 min, and the deposition thickness of the silicon zirconium coating was 8 μm, thereby obtaining a high-strength seamless steel pipe perforation head.

[0065] Example 10

[0066] (1) After the surface of the seamless steel pipe perforated plug substrate (prepared in Example 4) was cleaned and dried, an ion nitrocarburizing process was performed in a pulse power glow ion nitriding furnace in an argon atmosphere. The seamless steel pipe perforated plug substrate was used as a sample material. The atmosphere in the furnace was ammonia and acetone. The ammonia flow rate was 1.4 L / min, the acetone flow rate was 0.03 L / min, the working gas pressure was 700 Pa, the working voltage was 850 V, the working temperature was 600 ° C, and the holding time was 10 h. After the nitriding was completed, argon was filled and cooled to room temperature to obtain a nitrided seamless steel pipe perforated plug.

[0067] (2) Add 10 g of zirconium n-propoxide and 160 mL of tetrahydrofuran into a three-necked flask, stir evenly, then add 5.5 g of acetylacetone and 0.5 g of 1,2-propylene glycol, react at 50 °C for 3 h, then add 16 g of silylene resin, continue to react for 35 min, concentrate under reduced pressure, first cure at 280 °C for 5 h, then pyrolyze at 1450 °C for 4 h to obtain silicon zirconium powder.

[0068] (3) After the nitrided seamless steel pipe perforation head was cleaned and polished with argon ions, the silicon zirconium coating was deposited by radio frequency reactive magnetron sputtering using silicon zirconium powder as the target and the nitrided seamless steel pipe perforation head as the substrate. When sputtering silicon zirconium powder, the working gas pressure was 0.3 Pa, the sputtering gas was high-purity argon, the sputtering power was 210 W, the distance between the substrate and the target was 60 mm, the sputtering time was 50 min, and the deposition thickness of the silicon zirconium coating was 10 μm, thereby obtaining a high-strength seamless steel pipe perforation head.

[0069] Comparative Example 3

[0070] After the seamless steel pipe perforated plug substrate (prepared in Example 4) was cleaned and polished with argon ions, the silicon zirconium coating was deposited by radio frequency reactive magnetron sputtering using silicon zirconium powder as the target and the nitrided seamless steel pipe perforated plug as the substrate. When sputtering the silicon zirconium powder, the working gas pressure was 0.3 Pa, the sputtering gas was high-purity argon, the sputtering power supply power was 200 W, the distance between the substrate and the target was 65 mm, the sputtering time was 45 min, and the deposition thickness of the silicon zirconium coating was 2 μm, thereby obtaining a seamless steel pipe perforated plug.

[0071] Comparative Example 4

[0072] After the surface of the seamless steel pipe perforated plug substrate (prepared in Example 4) was cleaned and dried, an ion nitrocarburizing process was performed in a pulse power glow ion nitriding furnace in an argon atmosphere. The seamless steel pipe perforated plug substrate was used as a sample material. The furnace atmosphere was ammonia and acetone. The ammonia flow rate was 1.2 L / min, the acetone flow rate was 0.023 L / min, the working gas pressure was 600 Pa, the working voltage was 800 V, the working temperature was 550°C, and the holding time was 9 h. After the nitriding was completed, argon was filled and cooled to room temperature to obtain a nitrided seamless steel pipe perforated plug.

[0073] Tensile strength test: An electronic universal testing machine was used to test the mechanical properties of the perforated plug. During the test, the tensile speed was 2 mm / min, the paper feed speed was 1 mm / s, and the arithmetic mean of the test results of the three samples was taken as the final test result.

[0074] Wear resistance test: A wet sand rubber wheel three-body abrasive wear testing machine was used to test the wear resistance of the prepared seamless steel pipe perforation plug. The wear medium was a mixture of 1500g of 40-60 mesh quartz sand and 1000g of tap water. The test load was 100N, and the total grinding distance was 1677m. The mass difference of the sample before and after wear divided by the grinding distance was taken as the wear rate of the sample.

[0075] Table 3 Tensile strength and wear resistance test

[0076] Tensile strength (MPa) Wear rate (g / m) Example 6 1295 <![CDATA[9.56×10 -5 ]]> Example 7 1310 <![CDATA[6.24×10 -5 ]]> Example 8 1338 <![CDATA[3.05×10 -5 ]]> Example 9 1350 <![CDATA[2.85×10 -5 ]]> Example 10 1362 <![CDATA[1.67×10 -5 ]]> Comparative Example 3 1275 <![CDATA[6.32×10 -4 ]]> Comparative Example 4 1264 <![CDATA[8.63×10 -4 ]]>

[0077] It can be seen from the test results in the above table that with the nitriding and magnetron sputtering silicon-zirconium coating processes on the surface of the seamless steel pipe perforation plug substrate, the strength and wear resistance of the seamless steel pipe perforation plug are greatly improved. This is because ion soft nitriding is to introduce carbon-containing gases such as acetone into the ion nitriding atmosphere at the same time, and nitrogen and carbon atoms penetrate into the surface of the sample to form a supersaturated nitrogen and carbon solid solution, causing austenite lattice distortion, increasing dislocation density, and improving strength; at the same time, the alloy elements in the sample form nitrides or carbides with nitrogen and carbon, which are dispersed on the surface of the sample, so that the strength of the permeation layer is greatly improved; the silicon-zirconium coating has Silicon and chromium with excellent wear resistance can be used as hard phases to effectively resist the wear of external abrasive particles during the process of friction and wear. The crack sources and crack propagation paths of wear microcracks generated during wear are greatly restricted, and the sliding friction and chiseling of some abrasive particles on the coating surface can be converted into rolling, thereby reducing the wear of the coating by the abrasive particles, thereby improving the wear resistance of the seamless steel pipe perforated plug. Magnetron sputtering sputters the silicon zirconium coating material onto the surface of the plug substrate, and forms a layered silicon zirconium nitride coating with diffusion barrier properties with the nitrogen element on the substrate surface, thereby realizing the wear resistance and other properties of the perforated plug material.

[0078] Pipe penetration test: The prepared seamless steel pipe perforation plug was subjected to an on-site pipe penetration test, the tube blank temperature was 1150°C, and the plug size was 65mm in diameter × 180mm.

[0079] Table 4 Pipe penetration test results

[0080] Number of continuous pipes Wear Example 6 456 No obvious wear Example 7 524 No obvious wear Example 8 565 No obvious wear Example 9 586 No obvious wear Example 10 593 No obvious wear Comparative Example 3 322 There are cracks Comparative Example 4 245 There are cracks

[0081] It can be concluded from the above table that the steel pipe piercing plug of the present invention has higher wear resistance on the original basis, and has a longer service life when used on a piercing machine. It does not crack when working under rapid cooling and heating conditions, and basically eliminates early cracks, roughening, shortening, flat heads and other destructive phenomena.

[0082] The above embodiments are only exemplary embodiments of the present invention and are not intended to limit the present invention. The protection scope of the present invention is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present invention within the essence and protection scope of the present invention, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the present invention.

Claims

1. A high-strength seamless steel pipe perforation plug, characterized in that: The preparation process of the high-strength seamless steel pipe perforation plug is carried out according to the following steps: (1) 0.25-0.45% pure carbon, 0.45-0.65% pure silicon, 0.15-0.30% metal manganese, 5.2-7.5% metal chromium, 0.50-0.95% metal molybdenum, 0.36-0.58% metal vanadium, 2.05-2.86% metal nickel, 0.15-0.25% metal tungsten, 0.02-0.1% ceramic reinforcing agent and 0.05-0. 25% of fine-grained strengthening agent and the balance of metallic iron are added to a medium-frequency induction furnace, heated for smelting, and after being completely melted, poured into a preheated stainless steel mold, vacuumed for vacuum casting, and placed in a muffle furnace at 600-750°C for 30-50 minutes after forming, first quenched at 950-1100°C for 3-6 hours, then tempered at 550-700°C for 1-4 hours, and cooled with the furnace to obtain a seamless steel pipe perforated plug matrix; (2) After cleaning and drying the surface of the seamless steel pipe perforated plug substrate, an ion nitrocarburizing process is performed in a pulse power glow ion nitriding furnace in an argon atmosphere. The seamless steel pipe perforated plug substrate is used as a sample material. The furnace atmosphere is ammonia and acetone. The ammonia flow rate is 1-1.5 L / min, the acetone flow rate is 0.01-0.03 L / min, and the insulation time is 8-10 h. After the nitriding is completed, argon is filled and cooled to room temperature to obtain a nitrided seamless steel pipe perforated plug; (3) Add zirconium n-propoxide and tetrahydrofuran into a three-necked flask, stir evenly, add acetylacetone and 1,2-propylene glycol, react at 50-60°C for 2-3h, then add silylene resin, continue to react for 20-40min, concentrate under reduced pressure, perform curing and pyrolysis, and obtain silicon zirconium powder; (4) After the nitrided seamless steel pipe perforated plug is cleaned and polished with argon ions, the silicon zirconium powder is used as the target material and the nitrided seamless steel pipe perforated plug is used as the substrate, and the silicon zirconium coating is deposited by radio frequency reactive magnetron sputtering. When sputtering the silicon zirconium powder, the working pressure is 0.2-0.4 Pa, the sputtering gas is high-purity argon gas, the sputtering power is 150-250 W, the distance between the substrate and the target is 60-70 mm, and the sputtering time is 40-60 min to obtain a high-strength seamless steel pipe perforated plug; The fine crystal strengthening agent is any one of lanthanum oxide, cerium oxide or yttrium oxide; The preparation process of the silane resin is carried out according to the following steps: in a nitrogen atmosphere, in a four-necked flask equipped with a thermometer and a constant pressure dropping funnel, 320 mL of tetrahydrofuran and 321 mL of a 2.5 mol / L n-butyl lithium n-hexane solution are added, and after stirring evenly, 24 mL of trichloroethylene is added dropwise, and the reaction is carried out at -20°C for 2 hours, 100 mL of methyl dichlorosilane is added dropwise, and the reaction is continued for 2 hours, and finally 5 g of lithium aluminum tetrahydride powder is added, and the reaction is continued for 5 hours. After the reaction is completed, suction filtration is performed, and the lower layer of clarified filtrate is taken, washed with deionized water, and distilled under reduced pressure to obtain the silane resin.

2. The high-strength seamless steel pipe piercing plug according to claim 1, characterized in that: The ceramic reinforcing agent is any one of titanium carbide, titanium nitride or tungsten carbide.

3. The high-strength seamless steel pipe piercing plug according to claim 1, characterized in that: In the step (1), the smelting temperature is 900-1050° C. and the smelting time is 2-4 hours.

4. The high-strength seamless steel pipe piercing plug according to claim 1, characterized in that: The ion nitrocarburizing process parameters in step (2) are as follows: working gas pressure of 500-800 Pa, working voltage of 750-850 V, and working temperature of 500-600 °C.

5. The high-strength seamless steel pipe piercing plug according to claim 1, characterized in that: In the step (3), the ratio of zirconium n-propoxide, tetrahydrofuran, acetylacetone, 1,2-propylene glycol, and silylene resin is 1 g: (10-20) mL: (0.4-0.6) g: (0.03-0.05) g: (1-2) g.

6. The high-strength seamless steel pipe piercing plug according to claim 1, characterized in that: In the step (3), the curing temperature is 200-300° C. and the curing time is 2-5 hours.

7. The high-strength seamless steel pipe piercing plug according to claim 1, characterized in that: In the step (3), the pyrolysis temperature is 1200-1500° C. and the pyrolysis time is 3-6 hours.

8. The high-strength seamless steel pipe piercing plug according to claim 1, characterized in that: The deposition thickness of the silicon zirconium coating in step (4) is 2-10 μm.

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