A high-temperature resistant, high-strength, soluble aluminum alloy pipe and its preparation method

Abstract

This invention discloses a high-temperature resistant, high-strength, soluble aluminum alloy pipe and its preparation method. The preparation method includes: 1. Selecting and weighing metal raw materials according to the composition of the target product; 2. Staged heating and melting, followed by water-cooled mold casting; 3. Uniform annealing, removing risers, machining, and creating a central through hole; 4. Hot extrusion forming; 5. Solution aging treatment. This invention, through the rational proportioning of strengthening elements such as Mg, Zn, Cu, Fe, Cr, Si, and Mn, as well as functional elements Ga, In, and Sn in the aluminum alloy, combined with large extrusion deformation and solution aging heat treatment, enables multiple strengthening mechanisms, including solution strengthening, precipitation strengthening, and grain boundary strengthening, to exert a synergistic strengthening effect. This achieves controlled degradation of the soluble aluminum alloy material in ultra-high temperature and ultra-high pressure environments, and it exhibits high tensile strength in ultra-high temperature environments, meeting the working conditions of ultra-high temperature and ultra-high pressure, and is suitable for the field of oil and gas field development pipelines in the petroleum industry.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas field development technology in the petroleum industry, and specifically relates to a high-temperature resistant, high-strength soluble aluminum alloy pipe and its preparation method. Background Technology

[0002] The demand for soluble materials in the oil and gas drilling and production equipment sector is increasing, especially for components such as soluble tubing and packers. These components not only require excellent formability, but also face increasingly stringent requirements for mechanical properties due to the ultra-high temperature (170℃~250℃) and ultra-high pressure (>200MPa) environments they encounter during operation. Currently, soluble polymer materials and soluble ceramic materials suffer from drawbacks such as high cost, difficulty in fabricating large-size, complex-shaped components, and low high-temperature strength. While magnesium alloys possess excellent solubility, their processing and forming capabilities are poor, and the dissolution rate is difficult to control, preventing their true engineering applications. In contrast, aluminum alloys have low density, good formability, excellent high-temperature strength, and significant potential for solubility control, making them a promising candidate for the fabrication of key soluble components in the oil and gas drilling and production field.

[0003] The literature “Wang MF, Xiao DH, Sun BR, et al. Microstructure, mechanical properties and corrosion behavior of Al-Cu-Mg-Sn-Ga-In alloy. Journal of Alloys and Compounds, 2019, 776: 172-180.” discloses a soluble aluminum alloy with high compressive strength of up to 582 MPa. However, this literature only focuses on the preparation of alloy ingots and the analysis of precipitated phases, without addressing the study of alloy plasticity or the preparation of thin-walled complex components such as pipes. It is still some distance from engineering implementation.

[0004] Three invention patents from Shaanxi University of Science and Technology—CN114752827A ("A Low-Temperature Soluble Aluminum Alloy and Its Uses"), CN114717456A ("A High-Temperature Soluble Aluminum Alloy, Preparation Method and Its Uses"), and CN114686734A ("A High-Ductility Soluble Aluminum Alloy, Preparation Method and Its Uses")—all design Al-Mg-Ga-In-Sn soluble aluminum alloys, achieving controllable dissolution of the material within a temperature range of room temperature to 90℃. Invention patent CN116005046A ("A High-Elongation Soluble Aluminum Alloy, Its Preparation Method and Its Applications") from Central South University discloses an Al-Mg-Cu-Ga-In-Sn soluble aluminum alloy, achieving both rapid dissolution and moderate room-temperature strength. However, these patents cover a limited range of strengthening elements in their soluble aluminum alloys, with low content, and none have addressed research on the mechanical properties and solubility of the material in the ultra-high temperature range of 170℃ to 250℃. Furthermore, the soluble aluminum alloys designed in these patents have limited formability, and can only produce bars with a small extrusion ratio of less than 20, without involving the preparation of tubes with higher extrusion ratios.

[0005] China National Petroleum Corporation's invention patent CN115637357A, "A Soluble Aluminum Alloy," designs an Al-Mg-Ga-In soluble aluminum alloy for hydraulic fracturing operations. Its solubility is comparable to that of water or at least low-mineralization fluids, and its room-temperature tensile strength reaches 240 MPa. However, the alloy's plasticity is only 2.6%, making it difficult to process into thin-walled complex components such as pipes with large deformations. The Institute of Metal Research, Chinese Academy of Sciences' invention patent CN105950920A, "An Aluminum-Based Alloy Soluble in Water and Aqueous Media and Its Preparation Method," designs an Al-Mg-Cu-Ti-Ga-In-Sn soluble aluminum alloy. The initial reaction temperature and dissolution rate in water and aqueous media environments are controllable, making it suitable for manufacturing various downhole fracturing tools. However, this alloy's strength is geared towards casting; while it has high room-temperature strength, its compressive strain is less than 30%, limiting the processing of complex components with large deformations.

[0006] In summary, existing soluble aluminum alloys only meet the low-temperature dissolution performance requirements below 90℃, and cannot meet the application conditions of ultra-high temperature and ultra-high pressure ultra-deep well environments. Furthermore, currently, soluble aluminum alloys are mainly used in engineering fields to manufacture simple fracturing tools, and their elongation is relatively low, making it difficult to manufacture complex components such as pipes under large deformation conditions. Therefore, the key to designing new soluble aluminum alloys lies in rationally designing the element ratios and forming process parameters of soluble aluminum alloy materials to achieve high extrusion ratio extrusion deformation manufacturing of large-size components such as pipes, while possessing both controllable dissolution performance and excellent mechanical properties under complex ultra-high temperature and ultra-high pressure conditions. Therefore, there is an urgent need to develop a high-temperature resistant, high-strength soluble aluminum alloy pipe and its preparation method to achieve widespread engineering applications. Summary of the Invention

[0007] The technical problem to be solved by this invention is to provide a high-temperature resistant, high-strength, soluble aluminum alloy that addresses the shortcomings of the prior art. This method, through the rational proportioning of strengthening elements such as Mg, Zn, Cu, Fe, Cr, Si, and Mn, as well as functional elements Ga, In, and Sn in the aluminum alloy, combined with extrusion large deformation and solution aging heat treatment, allows multiple strengthening mechanisms, including solution strengthening, precipitation strengthening, and grain boundary strengthening, to exert a synergistic strengthening effect. This achieves controlled degradation of the soluble aluminum alloy material in ultra-high temperature and ultra-high pressure environments, and it exhibits high tensile strength in ultra-high temperature environments. This solves the problem that existing soluble aluminum alloys have poor solubility and poor plasticity at high temperatures, making it difficult to manufacture complex components such as pipes through large deformation.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for preparing high-temperature resistant, high-strength, soluble aluminum alloy tubing, characterized in that the method includes the following steps:

[0009] Step 1: Weighing: Select the metal raw materials for weighing according to the mass percentage composition of the target product, soluble aluminum alloy pipe: Mg 1.0%–4.0%, Zn 2.5%–7.0%, Cu 0.1%–3%, Fe 0.1%–0.5%, Cr 0.1%–0.4%, Si 0.1%–0.9%, Mn 0.05%–0.2%, Ga 0.5%–1.5%, In 0.5%–1.5%, Sn 0.5%–1.5%, with the balance being Al and unavoidable impurity elements. Al and Zn elements are introduced in the form of elemental metal raw materials, while Mg, Cu, Fe, Cr, Si, and Mn elements are introduced in the form of AlMg10 master alloy, AlCu50 master alloy, AlFe20 master alloy, AlCr5 master alloy, AlSi20 master alloy, and AlMn10 master alloy, respectively.

[0010] Step 2, Melting and Casting: First, melt the Al elemental metal raw material from the weighed metal raw material in Step 1 until it is completely melted. Then, heat the temperature to 750℃~770℃ and add Ga, In, and Sn. After stirring, hold the temperature for 10 minutes to ensure that the metal raw material is completely melted and stirred evenly. Then, heat the temperature to 830℃~850℃ and add Zn elemental metal raw material, AlMg10 master alloy, AlCu50 master alloy, AlFe20 master alloy, AlCr5 master alloy, AlSi20 master alloy, and AlMn10 master alloy. After stirring, hold the temperature for 30 minutes~50 minutes to ensure that the metal raw material and master alloy are completely melted to obtain an aluminum alloy melt. After removing the slag from the surface of the aluminum alloy melt, add Al5TiB grain refiner and hold the temperature for 30 minutes~50 minutes. After cooling the furnace to 740℃~770℃, cast it into a mold. After cooling to room temperature, demold to obtain a soluble aluminum alloy master material ingot.

[0011] Step 3, Uniform Annealing and Billet Processing: The soluble aluminum alloy base material ingot obtained in Step 2 is subjected to uniform annealing, cooled in the furnace and the riser is removed. Surface defects are removed by turning to obtain a billet with a smooth surface. Then, a through hole is machined in the center of the billet using a drilling machine to obtain the billet to be extruded.

[0012] Step 4, Hot Extrusion Molding: Select a 1250-ton extruder, heat the billet to be extruded obtained in Step 3 and quickly load it into the preheated extruder sleeve for hot extrusion molding to obtain a soluble aluminum alloy tube blank.

[0013] Step 5, Solution treatment and aging: The soluble aluminum alloy tube blank obtained in Step 4 is first subjected to solution treatment, then air-cooled to room temperature, and then subjected to aging treatment, and air-cooled to room temperature to obtain the soluble aluminum alloy tube; the soluble aluminum alloy tube has a tensile strength of up to 370MPa at 175℃.

[0014] The above-mentioned method for preparing high-temperature resistant, high-strength, soluble aluminum alloy pipe is characterized in that the mass of Al5TiB grain refiner added in step two is 0.7% of the mass of the aluminum alloy melt, and the mold is made of water-cooled 304 stainless steel.

[0015] The above-mentioned method for preparing high-temperature resistant, high-strength, soluble aluminum alloy tubing is characterized in that the homogenization annealing temperature in step three is 490℃ and the holding time is 2.5h.

[0016] The above-mentioned method for preparing high-temperature resistant, high-strength, soluble aluminum alloy tubing is characterized in that, in step four, the billet to be extruded is heated to 420℃~490℃, and the extrusion press sleeve is preheated to 390℃; the extrusion speed of the hot extrusion forming is 20mm / min~50mm / min, and the extrusion ratio is 10~35. These parameters ensure the smooth progress of the hot extrusion forming process.

[0017] The above-mentioned method for preparing high-temperature resistant and high-strength soluble aluminum alloy tubing is characterized in that, in step two, the dimensions of the soluble aluminum alloy master material ingot are Ф150mm × 265mm (diameter × height); in step three, the dimensions of the billet to be extruded are an outer diameter of 115mm, an inner diameter of 50mm, and a length of 200mm; and in step four, the outer diameter of the soluble aluminum alloy tubing blank is 53mm to 60mm, and the inner diameter is 50mm.

[0018] The above-mentioned method for preparing high-temperature resistant, high-strength, soluble aluminum alloy pipes is characterized in that the solution treatment temperature in step five is 440℃~530℃, and the holding time is 1h~2h; the aging treatment temperature is 100℃~180℃, and the holding time is 8h~24h.

[0019] Meanwhile, the present invention also discloses a high-temperature resistant, high-strength, soluble aluminum alloy pipe, characterized in that it is prepared by the above-described method.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. The aluminum alloy of this invention, through the rational proportioning of strengthening elements such as Mg, Zn, Cu, Fe, Cr, Si, and Mn, and the addition of soluble functional elements Ga, In, and Sn during the smelting process, allows the strengthening elements to dissolve into the aluminum matrix, ensuring the solid solution strengthening foundation of the aluminum alloy. Combined with grain boundary strengthening induced by large extrusion deformation and precipitation strengthening induced by solid solution aging heat treatment, multiple strengthening mechanisms are formed, enabling solid solution strengthening, precipitation strengthening, and grain boundary strengthening to play a synergistic strengthening role. This achieves controlled degradation of soluble aluminum alloy materials in ultra-high temperature and ultra-high pressure environments, and exhibits high tensile strength in ultra-high temperature environments, that is, it still has excellent strength in ultra-high temperature environments exceeding 170°C, with a tensile strength as high as 370 MPa at 175°C, meeting the working conditions of ultra-high temperature and ultra-high pressure, and is suitable for the field of oil and gas field development pipelines in the petroleum industry.

[0022] 2. This invention regulates the process by adding functional elements Ga, In, and Sn during preparation. Ga, In, and Sn can form In3Sn and InSn4 second phases, which disrupt the alumina film and allow the aluminum alloy to dissolve continuously. This breaks through the traditional contradiction between the strength and solubility of soluble alloys, and still has a controllable dissolution rate at high temperatures. Specifically, the mass dissolution rate in a neutral medium at 100°C is 0.2% / min to 1% / min.

[0023] 3. The aluminum alloy of the present invention incorporates strengthening elements and adds fewer functional elements, thereby reducing the loss of the original properties of the aluminum alloy and ensuring that the aluminum alloy has excellent room temperature / high temperature plasticity, with a room temperature tensile elongation at break greater than 18% and a 175°C elongation at break greater than 20%. This ensures that the aluminum alloy has excellent extrusion molding capability, and thin-walled components such as aluminum alloy tubes can be obtained by hot extrusion molding.

[0024] 4. The preparation process of this invention adopts a combination of staged heating and melting and water-cooled mold casting, which effectively controls the metallurgical defects of the melting and casting ingot, so that there are no obvious shrinkage cavities and porosity in the soluble aluminum alloy base ingot, thus improving the quality of high-temperature resistant and high-strength soluble aluminum alloy.

[0025] In summary, this invention achieves structural and functional integration by rationally designing the element ratios and forming process of soluble aluminum alloy materials. This enables the aluminum alloy to possess both controllable solubility and excellent mechanical properties under complex working conditions of ultra-high temperature and ultra-high pressure, and also has excellent formability. This allows for the large deformation fabrication of large-size thin-walled complex components such as aluminum alloy tubes.

[0026] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0027] Figure 1a This is a macroscopic morphology diagram of the soluble aluminum alloy tube prepared in Example 1 of the present invention.

[0028] Figure 1b This is a macroscopic morphology image of the end face of the soluble aluminum alloy tube prepared in Example 1 of the present invention.

[0029] Figure 2 This is a microstructure diagram of the soluble aluminum alloy tubing prepared in Example 1 of the present invention.

[0030] Figure 3 The image shows the room temperature tensile curve of the soluble aluminum alloy tube prepared in Example 1 of this invention.

[0031] Figure 4 The figure shows the room temperature tensile curve of the soluble aluminum alloy tube prepared in Example 1 of the present invention at 175°C.

[0032] Figure 5 This is a room temperature tensile curve of the soluble aluminum alloy tube prepared in Example 1 of the present invention at 200°C.

[0033] Figure 6 The graph shows the change in the mass ratio of soluble aluminum alloy pipes prepared in Examples 1-3 of this invention as dissolved over time in a 3% KCl solution at 100°C. Detailed Implementation

[0034] Example 1

[0035] This embodiment includes the following steps:

[0036] Step 1: Weighing: Select the metal raw materials for weighing according to the mass percentage composition of the target product, soluble aluminum alloy pipe: Mg 2.5%, Zn 7.0%, Cu 1.5%, Fe 0.5%, Cr 0.2%, Si 0.1%, Mn 0.2%, Ga 0.8%, In 0.8%, Sn 0.8%, with the balance being Al and unavoidable impurity elements. In each component, Al and Zn elements are introduced in the form of elemental metal raw materials, while Mg, Cu, Fe, Cr, Si, and Mn elements are introduced in the form of AlMg10 master alloy, AlCu50 master alloy, AlFe20 master alloy, AlCr5 master alloy, AlSi20 master alloy, and AlMn10 master alloy, respectively.

[0037] Step Two, Melting and Casting: First, melt all the Al elemental metal raw materials from the weighed metal raw materials in Step One. Then, heat to 770℃ and add Ga, In, and Sn. Stir and hold at this temperature for 10 minutes to ensure all the metal raw materials are melted and stirred evenly. Then, heat to 850℃ and add Zn elemental metal raw materials, AlMg10 master alloy, AlCu50 master alloy, AlFe20 master alloy, AlCr5 master alloy, AlSi20 master alloy, and AlMn10 master alloy. An intermediate alloy was stirred and held at a temperature of 30 minutes to ensure complete melting of the metal raw materials and the intermediate alloy, resulting in an aluminum alloy melt. After removing the slag from the surface of the aluminum alloy melt, an Al5TiB grain refiner was added and held at a temperature of 30 minutes. The melt was then cooled in the furnace to 740°C and cast into a water-cooled 304 stainless steel mold. After cooling to room temperature, the melt was demolded to obtain a soluble aluminum alloy base material ingot with a diameter × height of Ф150mm × 265mm. The mass of the Al5TiB grain refiner added was 0.7% of the mass of the aluminum alloy melt.

[0038] Step 3, Uniform Annealing and Billet Processing: The soluble aluminum alloy base material ingot obtained in Step 2 is heated to 490℃ and held for 2.5h for homogenization annealing. After furnace cooling, the riser is removed, and surface defects are removed by turning to obtain a billet with a smooth surface. Then, a through hole is machined in the center of the billet using a drilling machine to obtain a billet to be extruded with an outer diameter of 115mm, an inner diameter of 50mm, and a length of 200mm.

[0039] Step 4, Hot Extrusion Molding: Select a 1250-ton extruder, heat the billet to be extruded obtained in Step 3 to 450℃ and quickly load it into the extruder sleeve preheated to 390℃ for hot extrusion molding. The extrusion speed is 40mm / min and the extrusion ratio is 20 to obtain a soluble aluminum alloy tube blank with an outer diameter of 55mm and an inner diameter of 50mm.

[0040] Step 5, Solution treatment and aging: The soluble aluminum alloy tube blank obtained in Step 4 is first solution treated at 490℃ for 2 hours, then air-cooled to room temperature, and then aged at 120℃ for 24 hours, and air-cooled to room temperature to obtain the soluble aluminum alloy tube.

[0041] Figure 1a and Figure 1b Figure 1 shows the macroscopic morphology of the tube body and end face of the soluble aluminum alloy tube prepared in this embodiment. As can be seen from Figure 1, the surface of the soluble aluminum alloy tube has no obvious defects and the wall thickness is uniform.

[0042] Figure 2 This is a microstructure image of the soluble aluminum alloy tubing prepared in this embodiment. Figure 2It can be seen that the average grain size of the soluble aluminum alloy tube is 150 μm, and the strip-shaped micron-sized low-melting-point second phase is distributed at the grain boundaries, which is conducive to promoting the hydrolysis reaction of the aluminum alloy.

[0043] Figure 3 This is a room temperature tensile curve of the soluble aluminum alloy tube prepared in this embodiment. Figure 3 It can be seen that the room temperature tensile strength of this soluble aluminum alloy pipe is as high as 475 MPa, and the elongation at break reaches 17%.

[0044] Figure 4 This is a room temperature tensile curve of the soluble aluminum alloy tube prepared in this embodiment at 175°C. Figure 4 It can be seen that the room temperature tensile strength of this soluble aluminum alloy pipe is as high as 370MPa at 175℃, and the elongation at break reaches 24.7%.

[0045] Figure 5 This is a room temperature tensile curve of the soluble aluminum alloy tube prepared in this embodiment at 200°C. Figure 5 It can be seen that the room temperature tensile strength of this soluble aluminum alloy pipe is as high as 285MPa at 200℃, and the elongation at break reaches 18.5%.

[0046] Example 2

[0047] This embodiment includes the following steps:

[0048] Step 1: Weighing: Select the metal raw materials for weighing according to the mass percentage composition of the target product, soluble aluminum alloy pipe: Mg 1.0%, Zn 2.5%, Cu 0.1%, Fe 0.4%, Cr 0.1%, Si 0.5%, Mn 0.1%, Ga 1.5%, In 1.5%, Sn 1.5%, with the balance being Al and unavoidable impurity elements. In each component, Al and Zn elements are introduced in the form of elemental metal raw materials, while Mg, Cu, Fe, Cr, Si, and Mn elements are introduced in the form of AlMg10 master alloy, AlCu50 master alloy, AlFe20 master alloy, AlCr5 master alloy, AlSi20 master alloy, and AlMn10 master alloy, respectively.

[0049] Step Two, Melting and Casting: First, melt the Al elemental metal raw material from the weighed metal raw materials in Step One until it is completely melted. Then, raise the temperature to 760℃ and add Ga, In, and Sn. After stirring, hold the temperature for 10 minutes to ensure that the metal raw materials are completely melted and stirred evenly. Then, raise the temperature to 840℃ and add Zn elemental metal raw materials, AlMg10 master alloy, AlCu50 master alloy, AlFe20 master alloy, AlCr5 master alloy, AlSi20 master alloy, and AlMn10. The intermediate alloy was stirred and held at a temperature of 40 minutes to ensure that the metal raw materials and the intermediate alloy were completely melted, resulting in an aluminum alloy melt. After removing the slag from the surface of the aluminum alloy melt, Al5TiB grain refiner was added and held at a temperature of 40 minutes. After cooling to 750°C in the furnace, it was poured into a water-cooled 304 stainless steel mold. After cooling to room temperature, it was demolded to obtain a soluble aluminum alloy base material ingot with a diameter × height of Ф150mm × 265mm. The mass of the Al5TiB grain refiner added was 0.7% of the mass of the aluminum alloy melt.

[0050] Step 3, Uniform Annealing and Billet Processing: The soluble aluminum alloy base material ingot obtained in Step 2 is heated to 490℃ and held for 2.5h for homogenization annealing. After furnace cooling, the riser is removed, and surface defects are removed by turning to obtain a billet with a smooth surface. Then, a through hole is machined in the center of the billet using a drilling machine to obtain a billet to be extruded with an outer diameter of 115mm, an inner diameter of 50mm, and a length of 200mm.

[0051] Step 4, Hot Extrusion Molding: Select a 1250-ton extruder, heat the billet to be extruded obtained in Step 3 to 420℃ and quickly load it into the extruder sleeve preheated to 390℃ for hot extrusion molding. The extrusion speed is 50mm / min and the extrusion ratio is 10 to obtain a soluble aluminum alloy tube blank with an outer diameter of 60mm and an inner diameter of 50mm.

[0052] Step 5, Solution treatment and aging: The soluble aluminum alloy tube blank obtained in Step 4 is first solution treated at 440℃ for 1 hour, then air-cooled to room temperature, and then aged at 100℃ for 8 hours, and air-cooled to room temperature to obtain the soluble aluminum alloy tube.

[0053] Testing revealed that the soluble aluminum alloy tubing prepared in this embodiment exhibits a room temperature tensile strength of up to 410 MPa and a fracture elongation of 11%. At 175°C, the room temperature tensile strength reaches 304 MPa with a fracture elongation of 17%. At 200°C, the room temperature tensile strength reaches 267 MPa with a fracture elongation of 18%.

[0054] Example 3

[0055] This embodiment includes the following steps:

[0056] Step 1: Weighing: Select the metal raw materials for weighing according to the mass percentage composition of the target product, soluble aluminum alloy pipe: Mg 4.0%, Zn 4.0%, Cu 3.0%, Fe 0.1%, Cr 0.4%, Si 0.9%, Mn 0.05%, Ga 0.5%, In 0.5%, Sn 0.5%, with the balance being Al and unavoidable impurity elements. In each component, Al and Zn elements are introduced in the form of elemental metal raw materials, while Mg, Cu, Fe, Cr, Si, and Mn elements are introduced in the form of AlMg10 master alloy, AlCu50 master alloy, AlFe20 master alloy, AlCr5 master alloy, AlSi20 master alloy, and AlMn10 master alloy, respectively.

[0057] Step Two, Melting and Casting: First, melt the Al elemental metal raw material from the weighed metal raw materials in Step One until it is completely melted. Then, raise the temperature to 750℃ and add Ga, In, and Sn. After stirring, hold the temperature for 10 minutes to ensure that the metal raw materials are completely melted and stirred evenly. Then, raise the temperature to 830℃ and add Zn elemental metal raw materials, AlMg10 master alloy, AlCu50 master alloy, AlFe20 master alloy, AlCr5 master alloy, AlSi20 master alloy, and AlMn10. An intermediate alloy was stirred and held at a temperature of 50 minutes to ensure complete melting of the metal raw materials and the intermediate alloy, resulting in an aluminum alloy melt. After removing the slag from the surface of the aluminum alloy melt, an Al5TiB grain refiner was added and held at a temperature of 50 minutes. The melt was then cooled in the furnace to 740°C and cast into a water-cooled 304 stainless steel mold. After cooling to room temperature, the melt was demolded to obtain a soluble aluminum alloy base material ingot with a diameter × height of Ф150mm × 265mm. The mass of the Al5TiB grain refiner added was 0.7% of the mass of the aluminum alloy melt.

[0058] Step 3, Uniform Annealing and Billet Processing: The soluble aluminum alloy base material ingot obtained in Step 2 is heated to 490℃ and held for 2.5h for homogenization annealing. After furnace cooling, the riser is removed, and surface defects are removed by turning to obtain a billet with a smooth surface. Then, a through hole is machined in the center of the billet using a drilling machine to obtain a billet to be extruded with an outer diameter of 115mm, an inner diameter of 50mm, and a length of 200mm.

[0059] Step 4, Hot Extrusion Molding: Select a 1250-ton extruder, heat the billet to be extruded obtained in Step 3 to 490℃ and then quickly load it into the extruder sleeve preheated to 390℃ for hot extrusion molding. The extrusion speed is 20mm / min and the extrusion ratio is 35 to obtain a soluble aluminum alloy tube blank with an outer diameter of 53mm and an inner diameter of 50mm.

[0060] Step 5, Solution treatment and aging: The soluble aluminum alloy tube blank obtained in Step 4 is first solution treated at 530℃ for 1 hour, then air-cooled to room temperature, and then aged at 160℃ for 14 hours, and air-cooled to room temperature to obtain the soluble aluminum alloy tube.

[0061] Testing revealed that the soluble aluminum alloy tubing prepared in this embodiment exhibits a room temperature tensile strength of up to 460 MPa and a fracture elongation of 16%. At 175°C, the room temperature tensile strength reaches 344 MPa with a fracture elongation of 22%. At 200°C, the room temperature tensile strength reaches 315 MPa with a fracture elongation of 20%.

[0062] Figure 6 The graph shows the change in the mass ratio of soluble aluminum alloy pipes prepared in Examples 1-3 of this invention dissolved in a 3% KCl solution at 100°C over time. Figure 6 It can be seen that the soluble aluminum alloy pipes prepared in Examples 1 to 3 of the present invention have a mass dissolution rate of 0.2% / min to 1% / min in a neutral medium at 100°C.

[0063] In summary, the high-temperature resistant, high-strength, soluble aluminum alloy prepared by this invention exhibits high tensile strength in ultra-high temperature environments, meaning it retains excellent strength even at temperatures exceeding 170°C, with a tensile strength as high as 370 MPa at 175°C. Furthermore, it maintains a controllable dissolution rate at high temperatures, achieving controlled degradation of the soluble aluminum alloy material in ultra-high temperature and ultra-high pressure environments. This results in integrated structural and functional design with excellent formability, making it suitable for thin-walled complex components such as oil and gas field extraction pipelines in the petroleum industry.

[0064] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing high-temperature resistant, high-strength, soluble aluminum alloy tubing, characterized in that, The method comprises the following steps: Step one, weighing: according to the mass percentage composition of the target product, soluble aluminum alloy pipe material, select the metal raw materials for weighing: Mg 1.0%~4.0%, Zn 2.5%~7.0%, Cu 0.1%~3%, Fe 0.1%~0.5%, Cr 0.1%~0.4%, Si 0.1%~0.9%, Mn 0.05%~0.2%, Ga 0.5%~1.5%, In 0.5%~1.5%, Sn 0.5%~1.5%, the balance is Al and unavoidable impurity elements, and the Al, Zn elements in each component are introduced in the form of elemental metal raw materials, and the Mg, Cu, Fe, Cr, Si, Mn elements are introduced in the form of AlMg10 intermediate alloy, AlCu50 intermediate alloy, AlFe20 intermediate alloy, AlCr5 intermediate alloy, AlSi20 intermediate alloy, and AlMn10 intermediate alloy raw materials; Step two, melting and casting: first melt the Al elemental metal raw material in the metal raw material weighed in step one until it is completely melted, then heat to 750~770℃ and add Ga, In, Sn, stir for 10min to ensure that the metal raw materials are completely melted and uniformly stirred, then heat to 830~850℃ and add Zn elemental metal raw material, AlMg10 intermediate alloy, AlCu50 intermediate alloy, AlFe20 intermediate alloy, AlCr5 intermediate alloy, AlSi20 intermediate alloy, AlMn10 intermediate alloy, stir for 30~50min to ensure that the metal raw materials and intermediate alloys are completely melted, obtain an aluminum alloy melt, remove the surface dross of the aluminum alloy melt, add Al5TiB grain refiner and heat for 30~50min, cool to 740~770℃ in the furnace, and then cast into a mold, cool to room temperature, and demold to obtain a soluble aluminum alloy base material ingot; Step three, homogenizing annealing and blank processing: the soluble aluminum alloy base material ingot obtained in step two is homogenized and annealed, the riser is cut off after cooling in the furnace, and the surface defects are removed by turning to obtain a surface-finished blank, then a through hole is drilled in the center of the blank using a drill press to obtain a blank for extrusion; Step four, hot extrusion molding: select a 1250 ton extruder, heat the blank for extrusion obtained in step three and quickly load it into the preheated extruder sleeve for hot extrusion molding to obtain a soluble aluminum alloy pipe blank; Step five, solid solution aging treatment: the soluble aluminum alloy pipe blank obtained in step four is first subjected to solid solution treatment, air cooled to room temperature, then subjected to aging treatment, and air cooled to room temperature to obtain a soluble aluminum alloy pipe material; the tensile strength of the soluble aluminum alloy pipe material at 175℃ is as high as 370MPa.

2. The method of claim 1, wherein the high-temperature-resistant and high-strength soluble aluminum alloy pipe is prepared by the following steps: preparing a high-temperature-resistant and high-strength soluble aluminum alloy pipe blank; and performing a heat treatment on the pipe blank. The Al5TiB grain refiner added in step two has a mass of 0.7% of the mass of the aluminum alloy melt, and the material of the mold is water-cooled 304 stainless steel.

3. The method of claim 1, wherein the method further comprises the step of: The homogenizing annealing temperature in step three is 490℃, and the holding time is 2.5h. ​ 4. The method of claim 1, wherein the high-temperature-resistant and high-strength soluble aluminum alloy pipe is prepared by the following steps: preparing a high-temperature-resistant and high-strength soluble aluminum alloy pipe blank; and performing a heat treatment on the pipe blank. The blank to be extruded in step four is heated to 420-490 DEG C, and the extruder sleeve is preheated to 390 DEG C; the extrusion speed of the hot extrusion forming is 20-50 mm / min, and the extrusion ratio is 10-35.

5. The method of claim 1, wherein the high-temperature-resistant and high-strength soluble aluminum alloy pipe is prepared by the following steps: preparing a high-temperature-resistant and high-strength soluble aluminum alloy pipe blank; and performing a heat treatment on the pipe blank. The size of the soluble aluminum alloy base material ingot in step two is Ф150 mm x 265 mm; the size of the blank to be extruded in step three is an outer diameter of 115 mm, an inner diameter of 50 mm, and a length of 200 mm; and the outer diameter of the soluble aluminum alloy tube blank in step four is 53-60 mm, and the inner diameter is 50 mm.

6. The method of claim 1, wherein the high-temperature-resistant and high-strength soluble aluminum alloy pipe is prepared by the following steps: preparing a high-temperature-resistant and high-strength soluble aluminum alloy pipe blank; and performing a heat treatment on the pipe blank. The temperature of the solid solution treatment in step five is 440-530 DEG C, and the holding time is 1-2 h; the temperature of the aging treatment is 100-180 DEG C, and the holding time is 8-24 h.

7. A high temperature resistant, high strength, soluble aluminum alloy tubing characterized by, Prepared by the method of any one of claims 1-6.

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