A bimetallic metallurgical composite oil sleeve pipe blank and a preparation method and application thereof

Abstract

This invention discloses a bimetallic metallurgical composite oil casing blank, its preparation method, and its application, relating to the field of oil casing technology. The preparation method of the bimetallic metallurgical composite oil casing blank includes the following steps: using a low-alloy steel outer base tube with a specific chemical composition and a stainless steel / corrosion-resistant alloy inner liner, after roughening treatment, chemical nickel plating on the inner surface of the outer base tube, assembly, and hot isostatic pressing with specific process parameters, a metallurgical bonding interface is formed between the low-carbon low-alloy steel outer base tube and the stainless steel / corrosion-resistant alloy inner liner, consisting of atomic interdiffusion of the outer base tube, the nickel layer, and the inner liner. This interface has high bonding strength, not less than 300 MPa, and is uniform, dense, and defect-free, without a brittle intermetallic compound layer, ensuring that the bimetallic metallurgical composite oil casing blank can withstand subsequent large deformation processing such as hot piercing and hot rolling, and its integrity during service.

Description

Technical Field

[0001] This invention relates to the field of oil casing technology, and in particular to a bimetallic metallurgical composite oil casing blank, its preparation method, and its application. Background Technology

[0002] In oil and gas field development, especially in fields with high H2S, CO2, and Cl content - Deep, ultra-deep, and deep-sea oil and gas wells place extremely high demands on the corrosion resistance and mechanical properties of tubing strings. However, manufacturing the entire casing and tubing from corrosion-resistant alloys is extremely expensive. Using bimetallic composite casing and tubing can reduce costs. The preparation of such bimetallic composite tubing typically involves first producing a composite tube blank, which is then processed through hot extrusion, hot rolling and / or cold rolling, and heat treatment to achieve the final dimensions and performance. Among these processes, the interfacial bonding quality of the composite tube blank is crucial in determining the performance of the finished tubing.

[0003] However, there are significant differences in physical properties (such as the coefficient of thermal expansion) and metallurgical characteristics between the existing low-alloy steel used for the outer base tube and the austenitic stainless steel or nickel-based corrosion-resistant alloy used for the inner liner tube. Direct composite bonding can easily lead to the formation of brittle intermetallic compounds (such as σ phase and carbides) at the interface, which severely weakens the bonding strength. The bonding strength is usually less than 200 MPa, and interlayer delamination is likely to occur during subsequent processing or service.

[0004] Therefore, developing a method for preparing bimetallic metallurgical composite oil casing blanks with high interfacial bonding strength and uniform interface has significant industrial application value.

[0005] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0006] Based on the shortcomings of the prior art, the purpose of this invention is to provide a bimetallic metallurgical composite oil casing blank, its preparation method and application, aiming to solve the problem that the interfacial bonding strength of existing bimetallic metallurgical composite oil casing blanks still needs to be improved.

[0007] The technical solution of the present invention is as follows: In a first aspect, the present invention provides a method for preparing a bimetallic metallurgical composite oil casing blank, comprising the following steps: S1. Provide an outer base tube and an inner liner tube, and roughen the inner surface of the outer base tube and the outer surface of the inner liner tube so that the roughness of the inner surface of the outer base tube and the outer surface of the inner liner tube is 6.5 μm to 8.5 μm. The outer base tube comprises the following chemical components in weight percentage: The composition comprises: C 0.23%–0.30%, Si 0.15%–0.40%, P ≤0.015%, S ≤0.005%, Al 0.015%–0.035%, N ≤0.010%, O ≤0.002%, H ≤0.00015%; and includes one or more of the following chemical components in mass percentage: Mn 0.30%–1.60%, Cr 0.15%–1.30%, Mo 0.15%–0.80%, Ni 0.15%–0.50%, Cu 0.15%–0.30%, B 0.0005%–0.001%, V 0.01%–0.15%, Nb 0.01%–0.15%, Ti 0.01%–0.05%, RE 0.001%–0.020%, Ca 0.010% to 0.035%, balance being Fe and unavoidable impurities; The inner lining tube is made of 316L austenitic stainless steel, 028 corrosion-resistant alloy, Incoloy 825 corrosion-resistant alloy, G3 corrosion-resistant alloy or Inconel 625 corrosion-resistant alloy. S2. Perform chemical nickel plating on the inner surface of the roughened outer base tube to form a nickel layer with a thickness of 0.01 mm to 0.05 mm, thus obtaining an outer base tube with a nickel layer on the inner surface. S3. Place the roughened inner liner into the outer base tube with a nickel layer on its inner surface, and then perform incomplete sealing welding on both ends of the inner liner and the outer base tube to form an assembly. S4. Place the assembly in an inert atmosphere and heat it to 1050℃~1180℃, hold it at that temperature for 15~60 minutes. At the same time, when heating to 1050℃~1180℃ or during the holding process, apply a radial static pressure of 280 MPa~400 MPa to the assembly and hold it for 5~30 minutes. Then cool it during the holding or depressurization process to obtain the bimetallic metallurgical composite oil casing blank.

[0008] Optionally, the outer diameter of the outer base tube is 50 mm to 500 mm, and the wall thickness of the outer base tube is 10 mm to 60 mm; the wall thickness of the inner liner tube is 3 mm to 10 mm; and / or, Before roughening the inner surface of the outer base tube and the outer surface of the inner liner tube, the process also includes alkali washing, acid washing, water washing, and drying.

[0009] Optionally, the alkaline washing and acid washing steps specifically include: The outer base tube and the inner liner tube are placed in an alkaline degreasing solution at 60℃~80℃ and ultrasonically cleaned for 10~20 minutes to obtain an alkaline-washed outer base tube and an alkaline-washed inner liner tube. After alkali washing, the outer base tube is placed in a hydrochloric acid solution with an HCl concentration of 10wt% to 15wt% and soaked at room temperature for 5 to 15 minutes. After alkali washing, the inner liner is placed in a mixed acid solution with HNO3 concentration of 10wt% to 20wt% and HF concentration of 2wt% to 5wt%, and immersed at 40℃ to 50℃ for 3 to 8 minutes.

[0010] Optionally, the plating solution used in the electroless nickel plating is prepared by the following method: Mix 25 g / L to 30 g / L nickel sulfate, 25 g / L to 30 g / L reducing agent, 20 g / L to 30 g / L complexing agent, 0.5 mg / L to 1.5 mg / L stabilizer with water, and then adjust the pH of the system to 4.6 to 4.9 with ammonia or dilute sulfuric acid.

[0011] Optionally, the temperature of the plating solution used in the electroless nickel plating is 88℃~92℃.

[0012] Optionally, the reducing agent includes sodium hypophosphite, the stabilizer includes thiourea, and the complexing agent at 20 g / L to 30 g / L includes lactic acid at 15 g / L to 20 g / L and propionic acid at 5 g / L to 10 g / L.

[0013] Optionally, step S4 specifically includes: The assembly was placed in a hot isostatic pressing apparatus and evacuated to a vacuum level of ≤1×10⁻⁶. -2 After Pa, inert gas is introduced, and then the temperature is increased to 1050℃~1180℃ at a heating rate of 5~15℃ / min, and held for 15~60 minutes. Simultaneously, when the temperature is raised to 1050℃~1180℃ or during the heat preservation process, a radial static pressure of 280 MPa~400 MPa is applied to the assembly and the pressure is maintained for 5~30 minutes. Then, during the pressure holding or depressurization process, the tube blank is water-cooled to 400℃~600℃, and then depressurized and air-cooled to room temperature to obtain the bimetallic metallurgical composite oil casing blank.

[0014] Optionally, when the inner liner is made of 316L austenitic stainless steel, the temperature is raised to 1050℃~1100℃; When the inner liner is made of 028 corrosion-resistant alloy or Incoloy 825 corrosion-resistant alloy, the temperature is raised to 1100℃~1150℃. When the inner liner is made of G3 corrosion-resistant alloy or Inconel 625 corrosion-resistant alloy, the temperature is raised to 1130℃~1180℃.

[0015] In a second aspect, the present invention provides a bimetallic metallurgical composite oil casing blank, wherein the bimetallic metallurgical composite oil casing blank includes an outer base tube and an inner liner tube coaxially arranged from the outside to the inside, and the outer base tube and the inner liner tube are metallurgically bonded by a nickel layer between them. The outer base tube comprises the following chemical components in weight percentage: The composition comprises: C 0.23%–0.30%, Si 0.15%–0.40%, P ≤0.015%, S ≤0.005%, Al 0.015%–0.035%, N ≤0.010%, O ≤0.002%, H ≤0.00015%; and includes one or more of the following chemical components in mass percentage: Mn 0.30%–1.60%, Cr 0.15%–1.30%, Mo 0.15%–0.80%, Ni 0.15%–0.50%, Cu 0.15%–0.30%, B 0.0005%–0.001%, V 0.01%–0.15%, Nb 0.01%–0.15%, Ti 0.01%–0.05%, RE 0.001%–0.020%, Ca 0.010% to 0.035%, balance being Fe and unavoidable impurities; The inner lining tube is made of 316L austenitic stainless steel, 028 corrosion-resistant alloy, Incoloy 825 corrosion-resistant alloy, G3 corrosion-resistant alloy, or Inconel 625 corrosion-resistant alloy.

[0016] A third aspect of the present invention provides an application of a bimetallic metallurgical composite oil casing blank prepared by the preparation method described above, or a bimetallic metallurgical composite oil casing blank described above, in the preparation of bimetallic metallurgical composite oil casings.

[0017] Beneficial Effects: In this invention, the chemical composition of the outer base tube is first designed and matched with a corresponding inner liner tube. The outer base tube is made of low-alloy steel, with grades such as N80, R95, C110, Q125, or V140. The inner liner tube is made of stainless steel or a corrosion-resistant alloy. Then, the outer base tube and inner liner tube are roughened to achieve a surface roughness Ra value of 6.5 μm to 8.5 μm, increasing the actual surface area. This ensures the adhesion of subsequent plating layers and provides sufficient mechanical engagement and diffusion channels for diffusion bonding. Finally, a uniform, dense, and well-bonded nickel layer with a thickness of 0.01 mm to 0.05 mm is deposited on the inner surface of the roughened outer base tube using a chemical nickel plating method. Next, the roughened inner liner is placed on top of an outer base tube containing a nickel layer on its inner surface for assembly. Then, hot isostatic pressing is performed using the specific process parameters mentioned above. At high temperatures, the atoms at the interfaces of the outer base tube with its specific chemical composition, the nickel layer, and the inner liner made of a specific material undergo sufficient interdiffusion, forming a metallurgical bond. Simultaneously, no harmful thick, lamellar intermetallic compounds are formed. Under high pressure, the pressure is transmitted through the outer base tube wall, causing the inner liner and nickel layer to adhere tightly and undergo microscopic plastic deformation, promoting the closure of interface pores and atomic diffusion. This results in a bonding interface with high strength (not less than 300 MPa), uniform and dense structure, no defects, and no intermetallic compounds or continuous brittle phases. Finally, a bimetallic metallurgical composite tube blank with an interfacial shear strength of not less than 300 MPa between the outer base tube and the inner liner is obtained, ensuring that the bimetallic metallurgical composite tube blank can withstand subsequent large deformation processing such as hot piercing and hot rolling, and maintain its integrity during service.

[0018] In addition, the nickel layer also serves to prevent the transitional diffusion of elements such as Ti and Al from the outer base tube to the inner lining of the 825 corrosion-resistant alloy, thus preventing the formation of harmful phases. The coating can more effectively prevent the diffusion of elements such as Fe and Cr from the outer base tube into the 625 corrosion-resistant alloy, preventing a decline in the performance of its weld sensitized zone.

[0019] This invention uses an outer base tube with a specific chemical composition to match an inner liner tube of a specific material, and combines it with a nickel layer. Through the above-mentioned preparation method, a bimetallic metallurgical composite tube blank with an interfacial strength of not less than 300 MPa is prepared. This effectively solves the problem of low interfacial bonding strength caused by the huge differences in physical properties and metallurgical characteristics between the outer base tube and the inner liner tube in the prior art. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the preparation process of the bimetallic metallurgical composite oil casing blank in an embodiment of the present invention. Detailed Implementation

[0021] This invention provides a bimetallic metallurgical composite oil casing blank, its preparation method, and its application. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0023] If the embodiments of the present invention involve descriptions such as "first" or "second", such descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated.

[0024] This invention provides a method for preparing a bimetallic metallurgical composite oil casing blank, wherein, as shown in the embodiments of the present invention... Figure 1 As shown, it includes the following steps: S1. Provide an outer base tube and an inner liner tube, and roughen the inner surface of the outer base tube and the outer surface of the inner liner tube so that the roughness of the inner surface of the outer base tube and the outer surface of the inner liner tube is 6.5 μm to 8.5 μm. The outer base tube comprises the following chemical components in weight percentage: The composition comprises: C (carbon) 0.23%–0.30%, Si (silicon) 0.15%–0.40%, P (phosphorus) ≤0.015%, S (sulfur) ≤0.005%, Al (aluminum) 0.015%–0.035%, N (nitrogen) ≤0.010%, O (oxygen) ≤0.002%, H (hydrogen) ≤0.00015%; and includes one or more of the following chemical components in mass percentage: Mn (manganese) 0.30%–1.60%, Cr (chromium) 0.15%–1.30%, Mo… Molybdenum (Mo) 0.15%–0.80%, Ni (Ni) 0.15%–0.50%, Cu (Copper) 0.15%–0.30%, B (Boron) 0.0005%–0.001%, V (Vanadium) 0.01%–0.15%, Nb (Niobium) 0.01%–0.15%, Ti (Titanium) 0.01%–0.05%, RE (Rare Earth Elements) 0.001%–0.020%, Ca (Calcium) 0.010%–0.035%, with the balance being Fe (Iron) and unavoidable impurities; The inner lining tube is made of 316L austenitic stainless steel, 028 corrosion-resistant alloy, Incoloy 825 corrosion-resistant alloy, G3 corrosion-resistant alloy or Inconel 625 corrosion-resistant alloy. S2. Perform chemical nickel plating on the inner surface of the roughened outer base tube to form a nickel layer with a thickness of 0.01 mm to 0.05 mm, thus obtaining an outer base tube with a nickel layer on the inner surface. S3. The roughened inner liner is placed in the outer base tube with a nickel layer on its inner surface, and then the two ends of the inner liner and the outer base tube are partially sealed to form an assembly (with a tube-in-tube structure). S4. Place the assembly in an inert atmosphere and heat it to 1050℃~1180℃, hold it at that temperature for 15~60 minutes. At the same time, when heating to 1050℃~1180℃ or during the holding process, apply a radial static pressure of 280 MPa~400 MPa to the assembly and hold it for 5~30 minutes. Then cool it during the holding or depressurization process to obtain the bimetallic metallurgical composite oil casing blank.

[0025] In this invention, the chemical composition of the outer base tube is first designed, and a matching inner liner tube is then selected. The outer base tube is made of low-alloy steel, with grades such as N80, R95, C110, Q125, or V140. The inner liner tube is made of stainless steel or a corrosion-resistant alloy. Then, both the outer base tube and the inner liner tube are roughened to achieve a surface roughness Ra value of 6.5 μm to 8.5 μm, increasing the actual surface area. This ensures the adhesion of subsequent plating layers and provides sufficient mechanical engagement and diffusion channels for diffusion bonding. Finally, a uniform, dense, and well-bonded nickel layer with a thickness of 0.01 mm to 0.05 mm is deposited on the inner surface of the roughened outer base tube using a chemical nickel plating method. Next, the roughened inner liner is placed on top of an outer base tube containing a nickel layer on its inner surface for assembly. Then, hot isostatic pressing is performed using the specific process parameters mentioned above. At high temperatures, the atoms at the interfaces of the outer base tube with its specific chemical composition, the nickel layer, and the inner liner made of a specific material undergo sufficient interdiffusion, forming a metallurgical bond. Simultaneously, no harmful thick, lamellar intermetallic compounds are formed. Under high pressure, the pressure is transmitted through the outer base tube wall, causing the inner liner and nickel layer to adhere tightly and undergo microscopic plastic deformation, promoting the closure of interface pores and atomic diffusion. This results in a bonding interface with high strength (not less than 300 MPa), uniform and dense structure, no defects, and no intermetallic compounds or continuous brittle phases. Finally, a bimetallic metallurgical composite tube blank with an interfacial shear strength of not less than 300 MPa between the outer base tube and the inner liner is obtained, ensuring that the bimetallic metallurgical composite tube blank can withstand subsequent large deformation processing such as hot piercing and hot rolling, and maintain its integrity during service.

[0026] Furthermore, in this embodiment, the nickel layer also serves to prevent the transitional diffusion of elements such as Ti and Al from the outer base tube to the inner lining of the 825 corrosion-resistant alloy, thus preventing the formation of harmful phases. The coating can more effectively prevent the diffusion of elements such as Fe and Cr from the outer base tube into the 625 corrosion-resistant alloy, preventing a decline in the performance of its weld sensitized zone.

[0027] This invention uses an outer base tube with a specific chemical composition to match an inner liner tube made of a specific material, and combines it with a nickel layer. Through the above-mentioned preparation method, a bimetallic metallurgical composite oil casing blank with an interface strength of not less than 300 MPa is prepared. This effectively solves the problem of low interface bonding strength caused by the huge differences in physical properties and metallurgical characteristics between the outer base tube and the inner liner tube in the prior art.

[0028] In step S1, the outer base tube is made of low-alloy steel, with steel grades of N80, R95, C110, Q125, or V140. The roles of different chemical components in the outer base tube are as follows: Carbon (C) is the most important strengthening element in steel. Increasing the C content can significantly improve the hardenability of steel and thus increase its strength. However, excessive C content will impair the ductility and toughness of the steel. Taking all factors into consideration, the C content should be controlled within the range of 0.23% to 0.30%.

[0029] Si is commonly found in steel as a precipitated element and deoxidizer. Appropriate amounts of Si can improve the hardenability of steel, thereby increasing its strength, corrosion resistance, and tempering stability. However, excessive Si content can increase the tendency for segregation in steel, promote the formation of banded structures, and thus impair the steel's ductility and toughness. Considering all factors, the Si content should ideally be controlled within the range of 0.15% to 0.40%.

[0030] Al reacts with oxygen to form fine, uniformly distributed oxides, which can refine grains and improve strength and toughness. It is also an important deoxidizer. The Al content should be controlled within the range of 0.015% to 0.035%.

[0031] Mn is mainly used to improve the hardenability of steel, thereby increasing its strength. It can partially replace the more expensive chromium (Cr). However, Mn has a strong tendency to segregate, and excessive content can lead to uneven microstructure and properties. Considering all factors, the Mn content should be controlled within the range of 0.30% to 1.60%.

[0032] Cr is mainly used to improve the hardenability and tempering stability of steel, thereby increasing its strength. However, excessive Cr content will increase costs. Considering all factors, the Cr content should be controlled within the range of 0.15% to 1.30%.

[0033] Mo is mainly used to improve the hardenability of steel, thereby increasing its strength and tempering stability; however, excessive content is not economically viable. Mo also helps to reduce phosphorus segregation. Considering all factors, the Mo content should be controlled within the range of 0.15% to 0.80%.

[0034] Ni is mainly used to improve the hardenability of steel, thereby increasing its strength and low-temperature toughness. It can also reduce the hot cracking tendency of Cu-containing steel, but excessive content will increase costs. Taking all factors into consideration, the Ni content should be controlled within the range of 0.15% to 0.50%.

[0035] Cu can improve corrosion resistance in non-oxidizing media and reduce susceptibility to pitting corrosion; it can also improve the fluidity of steel, thereby improving casting process performance. However, excessive content can lead to Cu embrittlement. Taking all factors into consideration, the Cu content should be controlled between 0.15% and 0.30%.

[0036] Adding boron (B) to steel can significantly improve its hardenability and thus its strength, but excessive amounts can cause boron embrittlement. Considering all factors, the B content should ideally be controlled within the range of 0.0005% to 0.001%.

[0037] When v is added to steel, it forms VC and VN with the carbon and nitrogen in the steel. This helps to inhibit austenite grain growth and refine the grains, thereby improving strength and toughness. However, excessive v content will form too many carbonitriding compounds, increasing the brittleness of the steel and leading to higher costs. Considering all factors, the v content should ideally be controlled within the range of 0.01% to 0.15%.

[0038] When nitrogen (Nb) is added to steel, it forms NbC and NbN compounds, which inhibit austenite grain growth and refine the grain structure, thereby improving strength and toughness. However, excessive Nb content can lead to the formation of too many carbon and nitrogen compounds, increasing the brittleness of the steel and raising costs. Considering all factors, the Nb content should ideally be controlled within the range of 0.01% to 0.15%.

[0039] Adding titanium (Ti) to steel has deoxidizing and nitrogen-fixing effects. It combines with carbon (C) and nitrogen (N) in the steel to form TiC and TiN, which inhibit austenite grain growth and refine the grain structure, thereby improving strength and toughness. However, excessive Ti content can lead to the formation of too many Ti carbon and nitrogen compounds, increasing the brittleness of the steel and raising costs. Considering all factors, the Ti content should ideally be controlled within the range of 0.01% to 0.05%.

[0040] RE has multiple functions, including purifying molten steel, refining grains, modifying inclusions, and alloying. Taking all factors into consideration, the content of RE should be controlled within the range of 0.001% to 0.020%.

[0041] Ca can improve the properties and morphology of inclusions, thereby enhancing the toughness and corrosion resistance of steel. Considering all factors, the Ca content should ideally be controlled within the range of 0.010% to 0.035%.

[0042] P is a harmful impurity element that mainly affects the ductility and toughness of steel. The P content should be controlled within the range of 0% to 0.015%.

[0043] Sulfur (S) is a harmful impurity element that mainly affects the ductility and toughness of steel. The S content should be controlled within the range of 0% to 0.005%.

[0044] N, H, and O are harmful gaseous elements that mainly affect the ductility and toughness of steel. Their contents should be controlled within the range of N ≤ 0.010%, O ≤ 0.002%, and H ≤ 0.00015%.

[0045] The aforementioned alloying elements and their content ranges are not only related to obtaining bimetallic composite tube blanks with excellent bonding strength, but also to the final bimetallic composite tube products that possess strength, plasticity, toughness, and corrosion resistance. These alloying elements and their constituent systems must also be adaptable to subsequent processing techniques such as hot piercing, hot continuous rolling, cold rolling, and heat treatment to ensure the production of bimetallic composite tube products for oil casing with excellent overall performance.

[0046] In some embodiments, the roughening process specifically includes: sandblasting with angular brown corundum abrasive with a particle size of 60-80 mesh (e.g., 60, 70, or 80 mesh), a sandblasting pressure (compressed air pressure) of 0.6 MPa-0.8 MPa (e.g., 0.6 MPa, 0.7 MPa, or 0.8 MPa), a spray gun angle of 75°, and a sandblasting distance of 150 mm-200 mm (e.g., 150 mm, 160 mm, 170 mm, 180 mm, 190 mm, or 200 mm).

[0047] In this embodiment, a pressure blasting machine can be specifically used.

[0048] In some embodiments, after the roughening process, the surface is further cleaned by blowing away dust with high-pressure dry air and then wiping with acetone and anhydrous ethanol in sequence to ensure that the surface is clean, dry and free of contamination.

[0049] In some embodiments, the outer diameter (i.e., outer diameter) of the outer base tube is 50 mm to 500 mm (e.g., 50 mm, 100 mm, 150 mm, 200 mm, 250 mm, 300 mm, 350 mm, 400 mm, 450 mm, or 500 mm, etc.), and the wall thickness of the outer base tube is 10 mm to 60 mm (e.g., 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, or 60 mm, etc.); the wall thickness of the inner liner tube is 3 mm to 10 mm (e.g., 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm, etc.).

[0050] In some embodiments, before roughening the inner surface of the outer base tube and the outer surface of the inner liner tube, the process includes steps of alkaline washing, acid washing, water washing, and drying.

[0051] In some embodiments, the alkaline washing (specifically ultrasonic alkaline washing) step specifically includes: Place the outer base tube and the inner liner tube (which can be placed simultaneously or separately) in an alkaline degreasing solution at 60℃~80℃ (e.g., 60℃, 70℃ or 80℃) and ultrasonically clean them for 10~20 minutes (e.g., 10 minutes, 15 minutes or 20 minutes) to obtain the alkaline-washed outer base tube and the alkaline-washed inner liner tube.

[0052] The alkaline degreasing solution includes the following components in varying amounts: NaOH 30 g / L~50 g / L, Na2CO3 20 g / L~30 g / L, Na3PO4 10 g / L~20 g / L, surfactant 2 g / L~5 g / L, and water.

[0053] The surfactant includes at least one of potassium phenol ethoxyphosphate (PPE1040K), alkyl glycoside (APG), and alkylphenol polyoxyethylene ether. The alkyl glycoside includes n-hexyl glucoside (APG06), and the alkylphenol polyoxyethylene ether includes at least one of polyoxyethylene-8-octylphenyl ether (X-100).

[0054] Specifically, the surfactant is a compound of APG06, PPE1040K and X-100 in a mass ratio of 2:2:1.

[0055] In some embodiments, the pickling step (aimed at removing the oxide film) specifically includes: After alkali washing, place the outer base tube in a hydrochloric acid solution with an HCl concentration of 10wt% to 15wt% (wt% is the mass percentage) and soak it at room temperature for 5 to 15 minutes (e.g., 5 minutes, 6 minutes, 7 minutes, 8 minutes, 10 minutes, 12 minutes, or 15 minutes, etc.). After alkali washing, place the inner liner in a mixed acid solution with HNO3 concentration of 10wt% to 20wt% and HF concentration of 2wt% to 5wt%, and immerse it at 40℃ to 50℃ (e.g., 40℃, 42℃, 45℃, 48℃ or 50℃, etc.) for 3 to 8 minutes (e.g., 3 minutes, 4 minutes, 5 minutes, 6 minutes, 7 minutes or 8 minutes, etc.).

[0056] In step S2, in some embodiments, the plating solution used for electroless nickel plating is prepared by the following method: Mix 25 g / L to 30 g / L nickel sulfate, 25 g / L to 30 g / L reducing agent, 20 g / L to 30 g / L complexing agent, 0.5 mg / L to 1.5 mg / L stabilizer with water, and then adjust the pH of the system to 4.6 to 4.9 with ammonia or dilute sulfuric acid.

[0057] The specific amounts of nickel sulfate can be 25 g / L, 26 g / L, 27 g / L, 28 g / L, 29 g / L, or 30 g / L, etc.; the specific amounts of reducing agent can be 25 g / L, 26 g / L, 27 g / L, 28 g / L, 29 g / L, or 30 g / L; the specific amounts of complexing agent can be 25 g / L, 26 g / L, 27 g / L, 28 g / L, 29 g / L, or 30 g / L; and the specific amounts of stabilizer can be 0.5 mg / L, 0.6 mg / L, 0.8 mg / L, 1 mg / L, 1.2 mg / L, 1.3 mg / L, or 1.5 mg / L, etc.

[0058] In some embodiments, the reducing agent includes sodium hypophosphite, the stabilizer includes thiourea, and the complexing agent at 20 g / L to 30 g / L includes lactic acid at 15 g / L to 20 g / L (e.g., 15 g / L, 16 g / L, 17 g / L, 18 g / L, 19 g / L, or 20 g / L, etc.) and propionic acid at 5 g / L to 10 g / L (e.g., 5 g / L, 6 g / L, 7 g / L, 8 g / L, 9 g / L, or 10 g / L, etc.).

[0059] In some embodiments, the temperature of the plating solution used for electroless nickel plating is 88°C to 92°C, for example, 88°C, 89°C, 90°C, 91°C or 92°C.

[0060] During the electroless nickel plating process, the outer base tube is vertically immersed in the plating solution, ensuring complete wetting of the inner wall. Gentle stirring is maintained throughout the plating process, with a growth rate of approximately 10 μm / h to 15 μm / h. By controlling the plating time (typically 1 to 5 hours), a dense, uniform nickel layer (silver-white in color) with a thickness of 0.01 mm to 0.05 mm is obtained. This nickel layer exhibits good adhesion to the inner wall of the outer base tube and low porosity. After electroless nickel plating is completed, the outer base tube is removed, rinsed with hot deionized water at 60℃ to 80℃, and then dried.

[0061] In step S3, in some embodiments, the roughened inner liner is coaxially placed inside the outer base tube, whose inner surface has a nickel layer. The gap between them (i.e., the distance between the outer surface of the inner liner and the inner surface of the outer base tube with the plating, which is also half the difference between the inner diameter of the outer base tube with the nickel plating and the outer diameter of the inner liner) is 0.3 mm to 0.8 mm, for example, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, or 0.8 mm. A gap that is too small is not conducive to assembly and affects subsequent pressure transmission, while a gap that is too large will lead to uneven pressure at the bonding interface.

[0062] Specifically, the outer base tube, with a nickel layer on its inner surface, is placed horizontally. Using a specialized centering clamp, the roughened inner liner tube is slowly and smoothly pushed into the outer base tube along its axis, ensuring coaxiality of the two tubes and uniform annular gap along the entire length. For long tubes, a multi-point diameter gauge can be used for online monitoring. After assembly, the ends of the two tubes are partially sealed to prevent displacement and separation. In the subsequent hot isostatic pressing process, the partial sealing allows any moisture and air that may be present in the gap between the inner and outer tubes to escape.

[0063] In some implementations, step S4 specifically includes: The assembly is placed in a hot isostatic pressing apparatus (such as a hot isostatic pressing furnace or a large induction heating pressure device with radial pressurization function) and evacuated to a vacuum of ≤1×10⁻⁶. -2 After Pa, inert gas is introduced, and then the temperature is increased to 1050℃~1180℃ (e.g., 1050℃, 1060℃, 1070℃, 1080℃, 1090℃, 1100℃, 1120℃, 1150℃ or 1180℃, etc.) at a heating rate of 5~15℃ / min, and held for 15~60 minutes (e.g., 15, 20, 25, 30, 35, 40, 45, 50, 55 or 60 minutes). Simultaneously, when the temperature is raised to 1050℃~1180℃ or during the heat preservation process, a radial static pressure of 280 MPa~400 MPa (e.g., 280 MPa, 290 MPa, 300 MPa, 320 MPa, 350 MPa, 380 MPa or 400 MPa, etc.) is applied to the assembly and the pressure is maintained for 5~30 minutes (e.g., 5 minutes, 6 minutes, 8 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes or 30 minutes, etc.). Then, during the pressure holding or depressurization process, the tube blank is water-cooled to 400℃~600℃ (e.g., water-cooled to 600℃, 500℃, 400℃, etc.), and then depressurized and air-cooled to room temperature to obtain the bimetallic metallurgical composite oil casing blank.

[0064] In this embodiment, during the high-temperature insulation process, the nickel transition layer undergoes sufficient atomic interdiffusion with the two side metals (outer base tube steel and inner cladding alloy) to form a diffusion metallurgical bond, while avoiding the formation of harmful thick lamellar intermetallic compounds. During the insulation stage or after reaching the insulation temperature, a uniform radial static pressure is applied through an external pressure system. This pressure is transmitted through the outer base tube wall, causing the outer surface of the inner cladding tube to adhere tightly to the nickel layer and undergo microscopic plastic deformation, promoting the closure of interface pores and atomic diffusion. In this invention, a metallurgical bonding interface consisting of interdiffusion zones is formed between the low-alloy steel outer base tube and the stainless steel / corrosion-resistant alloy inner cladding tube, with a bonding strength of not less than 300 MPa and no continuous brittle phase at the interface. In this embodiment, the cooling regime helps prevent sensitization of the corrosion-resistant material of the inner cladding tube and alleviates thermal stress.

[0065] In some embodiments, when the inner liner is made of 316L austenitic stainless steel, the temperature is raised to 1050℃~1100℃ (for example, it can be 1050℃, 1060℃, 1070℃, 1080℃, 1090℃ or 1100℃, etc.). When the inner liner is made of 028 corrosion-resistant alloy or Incoloy 825 corrosion-resistant alloy, the temperature is raised to 1100℃~1150℃ (for example, it can be 1100℃, 1110℃, 1120℃, 1130℃, 1140℃ or 1150℃, etc.). When the inner liner is made of G3 corrosion-resistant alloy or Inconel 625 corrosion-resistant alloy, the temperature is raised to 1130℃~1180℃ (for example, it can be 1130℃, 1140℃, 1150℃, 1160℃, 1170℃ or 1180℃, etc.).

[0066] This invention also provides a bimetallic metallurgical composite oil casing blank, wherein the bimetallic metallurgical composite oil casing blank includes an outer base tube and an inner liner tube coaxially arranged from the outside to the inside, and the outer base tube and the inner liner tube are metallurgically bonded by a nickel layer between them; The outer base tube comprises the following chemical components in weight percentage: The composition comprises: C 0.23%–0.30%, Si 0.15%–0.40%, P ≤0.015%, S ≤0.005%, Al 0.015%–0.035%, N ≤0.010%, O ≤0.002%, H ≤0.00015%; and includes one or more of the following chemical components in mass percentage: Mn 0.30%–1.60%, Cr 0.15%–1.30%, Mo 0.15%–0.80%, Ni 0.15%–0.50%, Cu 0.15%–0.30%, B 0.0005%–0.001%, V 0.01%–0.15%, Nb 0.01%–0.15%, Ti 0.01%–0.05%, RE 0.001%–0.020%, Ca 0.010% to 0.035%, balance being Fe and unavoidable impurities; The inner lining tube is made of 316L austenitic stainless steel, 028 corrosion-resistant alloy, Incoloy 825 corrosion-resistant alloy, G3 corrosion-resistant alloy, or Inconel 625 corrosion-resistant alloy.

[0067] This invention also provides an application of the bimetallic composite oil casing blank prepared by the method described above, or the bimetallic composite oil casing blank described above, in the preparation of bimetallic composite oil casings. The invention will be further illustrated below with specific examples.

[0068] In the following examples, the alkaline degreasing solution used includes the following components in varying amounts: NaOH 40 g / L, Na2CO3 25 g / L, Na3PO4 15 g / L, surfactant 3 g / L and water; The surfactant is composed of APG06, PPE1040K and X-100 in a mass ratio of 2:2:1.

[0069] The chemical composition and mass percentage of the outer base tube and inner liner tube used in the following embodiments are shown in Table 1.

[0070] Table 1. Chemical composition and mass percentage of the outer base tube and inner liner tube used in Examples 1-5

[0071] In Table 1, the chemical composition of the different outer base tubes contains Fe as the remainder and unavoidable impurities; the chemical composition of the inner liner tubes in Examples 1-3 contains Fe as the remainder and unavoidable impurities; and the chemical composition of the inner liner tubes in Examples 4 and 5 contains Ni as the remainder and unavoidable impurities.

[0072] "-" indicates that the element is not present. For example, in Example 1, the outer base tube does not contain Ni, Mo, Cu, B, Co, Nb, Ti, RE, and Ca.

[0073] In the following examples, the outer diameter refers to the outer diameter.

[0074] Example 1 This embodiment provides a method for preparing a bimetallic metallurgical composite oil casing blank, including the following steps: (1) Provide outer base tube and inner liner: the outer base tube is API 5L standard N80 steel grade, with an outer diameter of 139.7 mm, a wall thickness of 12.7 mm, and a length of 3.5 m; the inner liner is made of 316L austenitic stainless steel, with an outer diameter of 113 mm and a wall thickness of 4.0 mm.

[0075] The chemical compositions of the outer base tube and the inner liner tube are the same as those of the outer base tube and the inner liner tube in Example 1, as shown in Table 1. The preparation method of the outer base tube includes the following steps: According to the chemical composition and mass percentage of the outer base tube in Example 1 of Table 1, steelmaking and continuous casting were carried out to obtain continuously cast billets. The continuously cast billets were heated to 1180°C, held for 2 hours, and hot pierced. Then, hot continuous rolling was carried out in the temperature range of 1150-950°C (initial rolling temperature is 1150°C, final rolling temperature is 950°C). After rolling, the billets were air-cooled to obtain the outer base tube.

[0076] The preparation method of the inner liner includes the following steps: According to the chemical composition and mass percentage of the inner liner in Example 1 of Table 1, steelmaking and continuous casting were carried out to obtain continuously cast billets. The continuously cast billets were heated to 1190°C and held for 3 hours for hot piercing. Then, they were hot rolled in the temperature range of 1160°C to 1080°C (initial rolling temperature of 1160°C and final rolling temperature of 1080°C). After rolling, they were cooled by water spraying to obtain the inner liner.

[0077] (2) Surface pretreatment: The outer base tube and inner liner tube were immersed in an alkaline degreasing solution at 70°C and ultrasonically cleaned for 20 minutes to thoroughly remove oil stains. Then, the degreased outer base tube was placed in a hydrochloric acid solution with a concentration of 15wt% HCl and soaked at room temperature for 10 minutes, followed by deionization rinsing and drying. The degreased inner liner tube was placed in a mixed acid solution at 45°C (containing 20wt% HNO3 + 5wt% HF) and soaked for 6 minutes, followed by deionization rinsing and drying. A pressure sandblasting machine was used with angular brown corundum abrasive (70 mesh) at a compressed air pressure of 0.7 MPa, a spray gun angle of 75°, and a sandblasting distance of 170 mm to uniformly sandblast the inner surface of the treated outer base tube, resulting in a surface roughness Ra = 7.2 μm.

[0078] A pressure sandblasting machine was used with angular brown corundum abrasive (70 mesh) at a compressed air pressure of 0.7 MPa, a spray gun angle of 75°, and a sandblasting distance of 175 mm to uniformly sandblast the outer surface of the inner liner tube after the above treatment, so that its surface roughness Ra=7.8 μm.

[0079] After sandblasting, use high-pressure dry air to blow away dust, and then wipe the surface with acetone and anhydrous ethanol in turn to ensure that the outer base tube and inner liner tube are clean, dry and free of contamination.

[0080] (3) Electroless nickel plating: The pretreated outer base tube is vertically immersed in the plating solution maintained at 90°C to ensure complete wetting of the inner wall. Gentle stirring is maintained during the nickel plating process. The nickel plating time is 2 hours and the coating growth rate is 10 μm / h to obtain a coating with a thickness of 0.02 mm. Then the outer base tube is removed, rinsed with 70°C hot deionized water and dried.

[0081] The preparation method of the plating solution includes the following steps: Nickel sulfate (NiSO4·6H2O) 30 g / L, sodium hypophosphite (NaH2PO2·H2O) 30 g / L, lactic acid (C3H6O3) 20 g / L, propionic acid (C3H6O2) 10 g / L and thiourea ((NH2)2CS) 1.0 mg / L were mixed with water, and then ammonia was added to adjust the pH of the system to 4.8 to obtain the plating solution.

[0082] (4) Nested assembly: The outer base tube with a nickel layer on its inner surface is placed horizontally. Using a special centering clamp, the inner liner tube is slowly and steadily pushed into the outer base tube along the axis of the outer base tube to ensure that the two tubes are coaxial and that the annular gap along the entire length is uniform. Then, the ends of the two tubes are partially sealed to prevent displacement and separation, thus obtaining the assembly.

[0083] (5) Hot isostatic pressing diffusion bonding: The assembly is placed in a hot isostatic pressing furnace and evacuated to 1×10 -2 After Pa, high-purity argon gas (≥99.999%) is introduced, and the temperature is raised to 1080℃ at a rate of 15℃ / min and held for 30 minutes. At the same time, an isostatic pressure of 320 MPa is applied during the holding process and held for 15 minutes. The gas is then water-cooled to 400℃ under the holding pressure, and then the pressure is released. The gas is then removed from the furnace and air-cooled to room temperature to obtain a bimetallic metallurgical composite oil casing blank.

[0084] Tests and Results: The interfacial bonding strength of the bimetallic composite oil casing blank prepared above was tested using the compression-shear method and found to be 332 MPa. The interfacial bonding was good, with no continuous brittle phase.

[0085] Example 2 This embodiment provides a method for preparing a bimetallic metallurgical composite oil casing blank, including the following steps: (1) Provide outer base pipe and inner liner pipe: the outer base pipe is non-API 5L standard R95 high extrusion steel grade, with an outer diameter of 244.5 mm, a wall thickness of 15.1 mm, and a length of 3.5 m; the inner liner pipe is made of 028 corrosion resistant alloy, with an outer diameter of 213.5 mm and a wall thickness of 6.0 mm.

[0086] The chemical compositions of the outer base tube and the inner liner tube are the same as those of the outer base tube and the inner liner tube in Example 2, as shown in Table 1. The preparation method of the outer base tube includes the following steps: According to the chemical composition and mass percentage of the outer base tube in Example 2 of Table 1, steelmaking and continuous casting were carried out to obtain continuously cast billets. The continuously cast billets were heated to 1260°C, held for 2 hours, and hot pierced. Then, hot continuous rolling was carried out in the temperature range of 1230-950°C (initial rolling temperature is 1230°C, final rolling temperature is 950°C). After rolling, the billets were air-cooled to obtain the outer base tube.

[0087] The preparation method of the inner liner includes the following steps: According to the chemical composition and mass percentage of the inner liner in Example 2 of Table 1, steelmaking and continuous casting were carried out to obtain a continuously cast billet. The continuously cast billet was heated to 1190°C and held for 3 hours for hot piercing. Then, it was hot extruded in the temperature range of 1180-1140°C and then cooled by water spraying to obtain the inner liner.

[0088] (2) Surface pretreatment: The outer base tube and the inner liner tube were immersed in an alkaline degreasing solution at 70°C and ultrasonically cleaned for 20 minutes to thoroughly remove oil stains. Then, the degreased outer base tube was placed in a hydrochloric acid solution with a concentration of 15wt% HCl and soaked at room temperature for 10 minutes, followed by deionization rinsing and drying. The degreased inner liner tube was placed in a mixed acid solution at 45°C (containing 20wt% HNO3 + 5wt% HF) and soaked for 6 minutes, followed by deionization rinsing and drying.

[0089] A pressure sandblasting machine was used with angular brown corundum abrasive (70 mesh) at a compressed air pressure of 0.7 MPa, a spray gun angle of 75°, and a sandblasting distance of 175 mm to uniformly sandblast the inner surface of the outer base tube after the above treatment, so that its surface roughness Ra=7.5 μm.

[0090] A pressure sandblasting machine was used with angular brown corundum abrasive (70 mesh) at a compressed air pressure of 0.7 MPa, a spray gun angle of 75°, and a sandblasting distance of 175 mm to uniformly sandblast the outer surface of the inner liner tube after the above treatment, so that its surface roughness Ra=8.0 μm.

[0091] After sandblasting, use high-pressure dry air to blow away dust, and then wipe the surface with acetone and anhydrous ethanol in turn to ensure that the outer base tube and inner liner tube are clean, dry and free of contamination.

[0092] (3) Electroless nickel plating: The pretreated outer base tube is vertically immersed in the plating solution maintained at 90°C to ensure complete wetting of the inner wall. Gentle stirring is maintained during the nickel plating process. The nickel plating time is 3 hours and the coating growth rate is 10 μm / h to obtain a coating with a thickness of 0.03 mm. Then the outer base tube is removed, rinsed with 70°C hot deionized water and dried.

[0093] The preparation method of the plating solution includes the following steps: Nickel sulfate (NiSO4·6H2O) 30 g / L, sodium hypophosphite (NaH2PO2·H2O) 30 g / L, lactic acid (C3H6O3) 20 g / L, propionic acid (C3H6O2) 10 g / L, and thiourea ((NH2)2CS) 1.0 mg / L were mixed with water, and then ammonia was added to adjust the pH of the system to 4.9 to obtain the plating solution.

[0094] (4) Nested assembly: The outer base tube with a nickel layer on its inner surface is placed horizontally. Using a special centering clamp, the inner liner tube is slowly and steadily pushed into the outer base tube along the axis of the outer base tube to ensure that the two tubes are coaxial and that the annular gap along the entire length is uniform. Then, the ends of the two tubes are partially sealed to prevent displacement and separation, thus obtaining the assembly.

[0095] (5) Hot isostatic pressing diffusion bonding: The assembly is placed in a hot isostatic pressing furnace and evacuated to 1×10 -2 After Pa, high-purity argon gas (≥99.999%) is introduced, and the temperature is raised to 1140℃ at a rate of 15℃ / min and held for 40 minutes. At the same time, an isostatic pressure of 340 MPa is applied during the holding process and held for 20 minutes. The temperature is then water-cooled to 550℃ under the holding pressure, and then the pressure is released and the product is air-cooled to room temperature to obtain a bimetallic metallurgical composite oil casing blank.

[0096] Tests and Results: The interfacial bonding strength of the bimetallic composite oil casing blank prepared above was tested using the compression-shear method and found to be 347 MPa. The interfacial bonding was good, with no continuous brittle phase.

[0097] Example 3 This embodiment provides a method for preparing a bimetallic metallurgical composite oil casing blank, including the following steps: (1) Provide outer base pipe and inner liner: the outer base pipe is API 5L standard C110 steel grade (sulfur resistant), with an outer diameter of 177.8 mm, a wall thickness of 12.7 mm, and a length of 3.5 m; the inner liner is made of Incoloy 825 corrosion resistant alloy, with an outer diameter of 151 mm and a wall thickness of 5.0 mm.

[0098] The chemical compositions of the outer base tube and the inner liner tube are the same as those of the outer base tube and the inner liner tube in Example 3, as shown in Table 1. The preparation method of the outer base tube includes the following steps: According to the chemical composition and mass percentage of the chemical composition of the outer base tube in Example 3 of Table 1, steelmaking and continuous casting are carried out to obtain continuously cast billets. The continuously cast billets are heated to 1240°C, held for 2 hours, and hot piercing is performed. Then, hot continuous rolling is carried out in the temperature range of 1210°C to 950°C (initial rolling temperature is 1210°C, final rolling temperature is 950°C). After rolling, the billets are air-cooled to obtain the outer base tube.

[0099] The preparation method of the inner liner includes the following steps: According to the chemical composition and mass percentage of the inner liner in Example 3 of Table 1, steelmaking and continuous casting were carried out to obtain a continuously cast billet. The continuously cast billet was heated to 1150°C and held for 3 hours for hot piercing. Then, it was hot extruded in the temperature range of 1140 to 1080°C and then cooled by water spraying to obtain the inner liner.

[0100] (2) Surface pretreatment: The outer base tube and the inner liner tube were immersed in an alkaline degreasing solution at 70°C and ultrasonically cleaned for 20 minutes to thoroughly remove oil stains. Then, the degreased outer base tube was placed in a hydrochloric acid solution with a concentration of 15wt% HCl and soaked at room temperature for 10 minutes, followed by deionization rinsing and drying. The degreased inner liner tube was placed in a mixed acid solution at 45°C (containing 20wt% HNO3 + 5wt% HF) and soaked for 6 minutes, followed by deionization rinsing and drying.

[0101] A pressure sandblasting machine was used, with angular brown corundum abrasive (70 mesh) as the material. The compressed air pressure was controlled at 0.7 MPa, the spray gun angle was 75°, and the sandblasting distance was 175 mm. The inner surface of the outer base tube after the above treatment was uniformly sandblasted to achieve a surface roughness Ra=7.0 μm.

[0102] A pressure sandblasting machine was used with angular brown corundum abrasive (70 mesh) at a compressed air pressure of 0.7 MPa, a spray gun angle of 75°, and a sandblasting distance of 175 mm to uniformly sandblast the outer surface of the inner liner tube after the above treatment, so that its surface roughness Ra=7.5 μm.

[0103] After sandblasting, use high-pressure dry air to blow away dust, and then wipe the surface with acetone and anhydrous ethanol in turn to ensure that the outer base tube and inner liner are absolutely clean, dry and free of contamination.

[0104] (3) Electroless nickel plating: The pretreated outer base tube is vertically immersed in a plating solution maintained at 90°C to ensure complete wetting of the inner wall. Gentle stirring is maintained during the nickel plating process. The nickel plating time is 4 hours and the coating growth rate is 10 μm / h to obtain a coating with a thickness of 0.04 mm. Then the outer base tube is removed, rinsed with 70°C hot deionized water and dried.

[0105] The preparation method of the plating solution includes the following steps: Nickel sulfate (NiSO4·6H2O) 30 g / L, sodium hypophosphite (NaH2PO2·H2O) 30 g / L, lactic acid (C3H6O3) 20 g / L, propionic acid (C3H6O2) 10 g / L and thiourea ((NH2)2CS) 1.0 mg / L were mixed with water, and then ammonia was added to adjust the pH of the system to 4.9 to obtain the plating solution.

[0106] (4) Nested assembly: The outer base tube with a nickel layer on its inner surface is placed horizontally. Using a special centering clamp, the inner liner tube is slowly and steadily pushed into the outer base tube along the axis of the outer base tube to ensure that the two tubes are coaxial and that the annular gap along the entire length is uniform. Then, the ends of the two tubes are partially sealed to prevent displacement and separation, thus obtaining the assembly.

[0107] (5) Hot isostatic pressing diffusion bonding: The assembly is placed in a hot isostatic pressing furnace and evacuated to 1×10 -2 After Pa, high-purity argon gas (≥99.999%) is introduced, and the temperature is raised to 1130℃ at a rate of 15℃ / min and held for 45 minutes. At the same time, an isostatic pressure of 360 MPa is applied during the holding process and held for 20 minutes. The temperature is then water-cooled to 550℃ under the holding pressure, and then the pressure is released and the tube is air-cooled to room temperature to obtain a bimetallic metallurgical composite oil casing blank.

[0108] In this embodiment, the nickel layer also serves to prevent the transitional diffusion of elements such as Ti and Al from the outer base pipe to the 825 corrosion-resistant alloy inner liner, forming harmful phases. Tests and results: The interfacial bonding strength of the bimetallic composite oil casing blank prepared above was tested using the compression-shear method and found to be 365 MPa. The interfacial bonding is good, with no continuous brittle phases.

[0109] Example 4 This embodiment provides a method for preparing a bimetallic metallurgical composite oil casing blank, including the following steps: (1) Provide outer base pipe and inner liner: the outer base pipe is API 5L standard Q125 steel grade, with an outer diameter of 339.7 mm, a wall thickness of 17.5 mm, and a length of 3.5 m; the inner liner is made of Inconel 625 corrosion resistant alloy, with an outer diameter of 303.5 mm and a wall thickness of 8.0 mm.

[0110] The chemical compositions of the outer base tube and the inner liner tube are the same as those of the outer base tube and the inner liner tube in Example 4, as shown in Table 1. The preparation method of the outer base tube includes the following steps: According to the chemical composition and mass percentage of the outer base tube in Example 4 of Table 1, steelmaking and continuous casting were carried out to obtain continuously cast billets. The continuously cast billets were heated to 1230°C, held for 2 hours, and hot pierced. Then, hot continuous rolling was carried out in the temperature range of 1200-950°C (initial rolling temperature of 1200°C and final rolling temperature of 950°C). After rolling, the billets were air-cooled to obtain the outer base tube.

[0111] The preparation method of the inner liner includes the following steps: According to the chemical composition and mass percentage of the inner liner in Example 4 of Table 1, steelmaking and continuous casting were carried out to obtain a continuously cast billet. The continuously cast billet was heated to 1160°C and held for 3 hours for hot piercing. Then, it was hot extruded in the temperature range of 1150-1000°C and then cooled by water spraying to obtain the inner liner.

[0112] (2) Surface pretreatment: The outer base tube and the inner liner tube were immersed in an alkaline degreasing solution at 70°C and ultrasonically cleaned for 20 minutes to thoroughly remove oil stains. Then, the degreased outer base tube was placed in a hydrochloric acid solution with a concentration of 15wt% HCl and soaked at room temperature for 10 minutes, followed by deionization rinsing and drying. The degreased inner liner tube was placed in a mixed acid solution at 45°C (containing 20wt% HNO3 + 5wt% HF) and soaked for 6 minutes, followed by deionization rinsing and drying.

[0113] A pressure sandblasting machine was used with angular brown corundum abrasive (70 mesh) at a compressed air pressure of 0.7 MPa, a spray gun angle of 75°, and a sandblasting distance of 175 mm to uniformly sandblast the inner surface of the outer base tube after the above treatment, so that its surface roughness Ra=8.0 μm.

[0114] A pressure sandblasting machine was used with angular brown corundum abrasive (70 mesh) at a compressed air pressure of 0.7 MPa, a spray gun angle of 75°, and a sandblasting distance of 175 mm to uniformly sandblast the outer surface of the inner liner tube after the above treatment, so that its surface roughness Ra=7.2 μm.

[0115] After sandblasting, use high-pressure dry air to blow away dust, and then wipe the surface with acetone and anhydrous ethanol in turn to ensure that the outer base tube and inner liner are absolutely clean, dry and free of contamination.

[0116] (3) Electroless nickel plating: The pretreated outer base tube is vertically immersed in the plating solution maintained at 90°C to ensure complete wetting of the inner wall. Gentle stirring is maintained during the nickel plating process. The nickel plating time is 5 hours and the coating growth rate is 10 μm / h to obtain a coating with a thickness of 0.05 mm. Then the outer base tube is removed, rinsed with 70°C hot deionized water and dried.

[0117] The preparation method of the plating solution includes the following steps: Nickel sulfate (NiSO4·6H2O) 30 g / L, sodium hypophosphite (NaH2PO2·H2O) 30 g / L, lactic acid (C3H6O3) 20 g / L, propionic acid (C3H6O2) 10 g / L and thiourea ((NH2)2CS) 1.0 mg / L were mixed with water, and then ammonia was added to adjust the pH of the system to 4.9 to obtain the plating solution.

[0118] (4) Nested assembly: The outer base tube with a nickel layer on its inner surface is placed horizontally. Using a special centering clamp, the inner liner tube is slowly and steadily pushed into the outer base tube along the axis of the outer base tube to ensure that the two tubes are coaxial and that the annular gap along the entire length is uniform. Then, the ends of the two tubes are partially sealed to prevent displacement and separation, thus obtaining the assembly.

[0119] (5) Hot isostatic pressing diffusion bonding: The assembly is placed in a hot isostatic pressing furnace and evacuated to 1×10 -2 After Pa, high-purity argon gas (≥99.999%) is introduced, and the temperature is raised to 1160℃ at a rate of 15℃ / min and held for 50 minutes. At the same time, an isostatic pressure of 380 MPa is applied during the holding process and held for 25 minutes. The temperature is then water-cooled to 600℃ under the holding pressure, and then the pressure is released and the tube is air-cooled to room temperature to obtain a bimetallic metallurgical composite oil casing blank.

[0120] In this embodiment, the 0.05 mm thick coating can more effectively block the diffusion of elements such as Fe and Cr from the outer base tube into the 625 corrosion-resistant alloy, preventing the performance of its weld sensitized zone from deteriorating.

[0121] Tests and Results: The interfacial bonding strength of the bimetallic composite oil casing blank prepared above was tested using the compression-shear method and found to be 388 MPa. The interfacial bonding was good, with no continuous brittle phase.

[0122] Example 5 This embodiment provides a method for preparing a bimetallic metallurgical composite oil casing blank, including the following steps: (1) Provide outer base tube and inner liner: the outer base tube is non-API 5L standard V140 ultra-high strength steel grade, with an outer diameter of 339.7 mm, a wall thickness of 25.4 mm, and a length of 3.5 m; the inner liner is made of G3 corrosion resistant alloy, with an outer diameter of 288 mm and a wall thickness of 10.0 mm.

[0123] The chemical compositions of the outer base tube and the inner liner tube are the same as those of the outer base tube and the inner liner tube in Example 5, as shown in Table 1. The preparation method of the outer base tube includes the following steps: According to the chemical composition and mass percentage of the chemical composition of the outer base tube in Example 5 of Table 1, steelmaking and continuous casting are carried out to obtain continuously cast billets. The continuously cast billets are heated to 1200°C, held for 2 hours, and hot pierced. Then, hot continuous rolling is carried out in the temperature range of 1170°C to 950°C (initial rolling temperature is 1170°C, final rolling temperature is 950°C). After rolling, the billets are air-cooled to obtain the outer base tube.

[0124] The preparation method of the inner liner includes the following steps: According to the chemical composition and mass percentage of the inner liner in Example 5 of Table 1, steelmaking and continuous casting were carried out to obtain a continuously cast billet. The continuously cast billet was heated to 1180°C and held for 3 hours for hot piercing. Then, it was hot extruded in the temperature range of 1170-1100°C and then cooled by water spraying to obtain the inner liner.

[0125] (2) Surface pretreatment: Same as in Example 1.

[0126] (3) Electroless nickel plating: The pretreated outer base tube is vertically immersed in a plating solution maintained at 90°C to ensure complete wetting of the inner wall. Gentle stirring is maintained during the nickel plating process. The nickel plating time is 2.5 hours, the coating growth rate is 10 μm / h, and a coating with a thickness of 0.025 mm is obtained. Then the outer base tube is removed, rinsed with 70°C hot deionized water, and dried.

[0127] The preparation method of the plating solution includes the following steps: Nickel sulfate (NiSO4·6H2O) 30 g / L, sodium hypophosphite (NaH2PO2·H2O) 30 g / L, lactic acid (C3H6O3) 20 g / L, propionic acid (C3H6O2) 10 g / L and thiourea ((NH2)2CS) 1.0 mg / L were mixed with water, and then ammonia was added to adjust the pH of the system to 4.9 to obtain the plating solution.

[0128] (4) Nested assembly: The outer base tube with a nickel layer on its inner surface is placed horizontally. Using a special centering clamp, the inner liner tube is slowly and steadily pushed into the outer base tube along the axis of the outer base tube to ensure that the two tubes are coaxial and that the annular gap along the entire length is uniform. Then, the ends of the two tubes are partially sealed to prevent displacement and separation, thus obtaining the assembly.

[0129] (5) Hot isostatic pressing diffusion bonding: The assembly is placed in a hot isostatic press and evacuated to a vacuum of 1×10⁻⁶. -2 After Pa, high-purity argon gas (≥99.999%) is introduced, and the temperature is raised to 1160℃ at a rate of 15℃ / min and held for 60 minutes. At the same time, an isostatic pressure of 350 MPa is applied during the holding process and held for 30 minutes. Under the holding pressure, the temperature is water-cooled to 600℃, and then the pressure is released. The product is then air-cooled to room temperature to obtain a bimetallic metallurgical composite oil casing blank.

[0130] Tests and Results: The interfacial bonding strength of the bimetallic composite oil casing blank prepared above was tested using the compression-shear method and found to be 341 MPa. The interfacial bonding was good, with no continuous brittle phase.

[0131] Comparative Example 1 This comparative example provides a method for preparing a bimetallic metallurgical composite oil casing blank. The only difference from Example 1 is that step (3) chemical nickel plating is omitted, and a protective atmosphere is not used in step (5). The hot isostatic pressing temperature is 950°C, the pressure is 100 MPa, and the pressure is maintained for 10 minutes during the heat preservation process. The blank is then cooled to room temperature with the furnace. Other process parameters are exactly the same as in Example 1.

[0132] After the bimetallic composite oil casing blank was prepared, a compression-shear test was conducted. The interfacial shear strength was only 180 MPa, and discontinuous Cr deposits were found at the interface. 23 C6 type carbides.

[0133] Comparative Example 2 This comparative example provides a method for preparing a bimetallic metallurgical composite oil casing blank, which differs from Example 3 only in that... Step (3) of electroless nickel plating is omitted. In step (5), no protective atmosphere is used, the hot isostatic pressing temperature is 1250℃, the pressure is 450 MPa, and the pressure is maintained for 15 minutes during the heat preservation process. The furnace is cooled to 700℃ and then air-cooled to room temperature after being taken out of the furnace. Other process parameters are exactly the same as in Example 3.

[0134] After the bimetallic composite oil casing blank was prepared, a pressure-shear test was conducted. The interfacial shear strength was only 185 MPa, and ultrasonic testing revealed local unbonded signals at the interface.

[0135] Comparative Example 3 This comparative example provides a method for preparing a bimetallic composite oil casing blank. The only difference from Example 4 is that step (3) of chemical nickel plating is omitted, and in step (5), a protective atmosphere is not used, the hot isostatic pressing temperature is 1200℃, the pressure is 200 MPa, and the pressure is maintained for 20 minutes during the heat preservation process. The pressure is then water-cooled to 800℃, and the blank is air-cooled to room temperature after removal from the furnace. Other process parameters are exactly the same as in Example 4. After obtaining the bimetallic composite oil casing blank, a pressure-shear test was performed. The interfacial shear strength was only 195 MPa, and ultrasonic testing revealed local unbonded signals at the interface.

[0136] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method for preparing a bimetallic metallurgical composite oil casing blank, characterized in that, Includes the following steps: S1. Provide an outer base tube and an inner liner tube, and roughen the inner surface of the outer base tube and the outer surface of the inner liner tube so that the roughness of the inner surface of the outer base tube and the outer surface of the inner liner tube is 6.5 μm to 8.5 μm. The outer base tube comprises the following chemical components in weight percentage: The composition comprises: C 0.23%–0.30%, Si 0.15%–0.40%, P ≤0.015%, S ≤0.005%, Al 0.015%–0.035%, N ≤0.010%, O ≤0.002%, H ≤0.00015%; and includes one or more of the following chemical components in mass percentage: Mn 0.30%–1.60%, Cr 0.15%–1.30%, Mo 0.15%–0.80%, Ni 0.15%–0.50%, Cu 0.15%–0.30%, B 0.0005%–0.001%, V 0.01%–0.15%, Nb 0.01%–0.15%, Ti 0.01%–0.05%, RE 0.001%–0.020%, Ca 0.010% to 0.035%, balance being Fe and unavoidable impurities; The inner lining tube is made of 316L austenitic stainless steel, 028 corrosion-resistant alloy, Incoloy 825 corrosion-resistant alloy, G3 corrosion-resistant alloy or Inconel 625 corrosion-resistant alloy. S2. Electroless nickel plating is performed on the inner surface of the roughened outer base tube to form a nickel layer with a thickness of 0.01 mm to 0.05 mm, resulting in an outer base tube with a nickel layer on the inner surface. S3. Place the roughened inner liner into the outer base tube with a nickel layer on its inner surface, and then perform incomplete sealing welding on both ends of the inner liner and the outer base tube to form an assembly. S4. Place the assembly in an inert atmosphere and heat it to 1050℃~1180℃, hold it at that temperature for 15~60 minutes. At the same time, when heating to 1050℃~1180℃ or during the holding process, apply a radial static pressure of 280 MPa~400 MPa to the assembly and hold it for 5~30 minutes. Then cool it during the holding or depressurization process to obtain the bimetallic metallurgical composite oil casing blank.

2. The preparation method according to claim 1, characterized in that, The outer diameter of the outer base tube is 50 mm to 500 mm, and the wall thickness of the outer base tube is 10 mm to 60 mm; the wall thickness of the inner liner tube is 3 mm to 10 mm; and / or, Before roughening the inner surface of the outer base tube and the outer surface of the inner liner tube, the process also includes alkali washing, acid washing, water washing, and drying.

3. The preparation method according to claim 2, characterized in that, The alkaline washing and acid washing steps specifically include: The outer base tube and the inner liner tube are placed in an alkaline degreasing solution at 60℃~80℃ and ultrasonically cleaned for 10~20 minutes to obtain an alkaline-washed outer base tube and an alkaline-washed inner liner tube. After alkali washing, the outer base tube is placed in a hydrochloric acid solution with an HCl concentration of 10wt% to 15wt% and soaked at room temperature for 5 to 15 minutes. After alkali washing, the inner liner is placed in a mixed acid solution with HNO3 concentration of 10wt% to 20wt% and HF concentration of 2wt% to 5wt%, and immersed at 40℃ to 50℃ for 3 to 8 minutes.

4. The preparation method according to claim 1, characterized in that, The electroless nickel plating solution is prepared by the following method: Mix 25 g / L to 30 g / L nickel sulfate, 25 g / L to 30 g / L reducing agent, 20 g / L to 30 g / L complexing agent, 0.5 mg / L to 1.5 mg / L stabilizer with water, and then adjust the pH of the system to 4.6 to 4.9 with ammonia or dilute sulfuric acid.

5. The preparation method according to claim 4, characterized in that, The temperature of the plating solution used in the electroless nickel plating is 88℃~92℃.

6. The preparation method according to claim 4, characterized in that, The reducing agent includes sodium hypophosphite, the stabilizer includes thiourea, and the complexing agent (20 g / L to 30 g / L) includes lactic acid (15 g / L to 20 g / L) and propionic acid (5 g / L to 10 g / L).

7. The preparation method according to claim 1, characterized in that, Step S4 specifically includes: The assembly is placed in a hot isostatic pressing apparatus, evacuated to <1x10 -2 Pa, inert gas is then introduced, and then heated to 1050°C to 1180°C at a heating rate of 5 to 15°C / min, and held for 15 to 60 minutes. Meanwhile, when the temperature is raised to 1050℃~1180℃ or during the heat preservation process, a radial static pressure of 280 MPa~400 MPa is applied to the assembly and the pressure is maintained for 5~30 minutes. Then, during the pressure holding or depressurization process, the tube blank is water-cooled to 400℃~600℃, and then depressurized and air-cooled to room temperature to obtain the bimetallic metallurgical composite oil casing blank.

8. The preparation method according to claim 7, characterized in that, When the inner liner is made of 316L austenitic stainless steel, the temperature is raised to 1050℃~1100℃. When the inner liner is made of 028 corrosion-resistant alloy or Incoloy 825 corrosion-resistant alloy, the temperature is raised to 1100℃~1150℃. When the inner liner is made of G3 corrosion-resistant alloy or Inconel 625 corrosion-resistant alloy, the temperature is raised to 1130℃~1180℃.

9. A bimetallic metallurgical composite oil casing blank, characterized in that, The bimetallic composite oil casing blank includes an outer base tube and an inner liner tube arranged coaxially from the outside to the inside, and the outer base tube and the inner liner tube are metallurgically bonded by a nickel layer between them. The outer base tube comprises the following chemical components in weight percentage: The composition comprises: C 0.23%–0.30%, Si 0.15%–0.40%, P ≤0.015%, S ≤0.005%, Al 0.015%–0.035%, N ≤0.010%, O ≤0.002%, H ≤0.00015%; and includes one or more of the following chemical components in mass percentage: Mn 0.30%–1.60%, Cr 0.15%–1.30%, Mo 0.15%–0.80%, Ni 0.15%–0.50%, Cu 0.15%–0.30%, B 0.0005%–0.001%, V 0.01%–0.15%, Nb 0.01%–0.15%, Ti 0.01%–0.05%, RE 0.001%–0.020%, Ca 0.010% to 0.035%, balance being Fe and unavoidable impurities; The inner lining tube is made of 316L austenitic stainless steel, 028 corrosion-resistant alloy, Incoloy 825 corrosion-resistant alloy, G3 corrosion-resistant alloy, or Inconel 625 corrosion-resistant alloy.

10. The application of a bimetallic metallurgical composite oil casing blank prepared by any one of the preparation methods of claims 1-8 or the bimetallic metallurgical composite oil casing blank of claim 9 in the preparation of bimetallic metallurgical composite oil casing.

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