Aluminum alloy strip of coiled tubing, manufacturing method of coiled tubing and coiled tubing

Abstract

The embodiment of the invention provides an aluminum alloy strip of a continuous oil pipe, a manufacturing method of the continuous oil pipe and the continuous oil pipe. The aluminum alloy strip comprises the following alloy elements in percentage by mass: 0 lt; si is less than or equal to 0.40%, 0 lt; 0.50% or less, 0 lt of Fe; the content of Cu is less than or equal to 0.25%, the content of Mn is 0.60-1.20%, and the content of Mg is 5.0-6.0%, 0 lt; cr is less than or equal to 0.25%, and Zn is 0.80%-1.20%, 0 lt; the aluminum alloy comprises the following components in percentage by weight: less than or equal to 0.20% of Ti, 0.10-0.20% of Ce, 0.05-0.10% of Ta and the balance According to the embodiment of the invention, on one hand, the chemical components of the aluminum alloy strip of the coiled tubing are optimized, on the other hand, the welding and heat treatment processes of the coiled tubing are effectively controlled and simplified, the production efficiency is remarkably improved, and by adding the spraying process, the mechanical damage resistance in the operation process can be improved; the composite coiled tubing which is uniform in structure, high in strength, long in fatigue life and excellent in wear resistance and corrosion resistance is obtained.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to the technical field of oil pipes, and more particularly, to an aluminum alloy strip for coiled tubing, a manufacturing method of coiled tubing, and coiled tubing. Background Art

[0002] Coiled tubing, also known as flexible tubing, is a single-piece jointless tubing that is several kilometers long and is wound around a drum and can be continuously lowered into or retrieved from a well. In recent years, coiled tubing technology has developed rapidly. Coiled tubing has excellent performance characteristics such as low operating cost, simplicity, time-saving, safety, and reliability, and is widely used in multiple fields such as sand washing, well flushing, logging, well completion, and drilling.

[0003] Gas lift operation is a common coiled tubing operation. In on-site operations, nitrogen and oxygen are separated through a membrane nitrogen production process. The purity of the obtained nitrogen is 95%-98%, and the remaining gas is a mixed gas of oxygen, water vapor, CO2, etc. In the high-temperature and high-pressure environment of oil wells, the mixed gas has high corrosiveness, corrodes and falls off on the inner wall of the coiled tubing, accumulates at the bottom of the coiled tubing, resulting in blockage and failure, and seriously affecting the service life of the coiled tubing.

[0004] On the other hand, with the continuous development of oil and gas wells, the well depth is increasing day by day, and the length of the pipe body also increases accordingly. Due to the relatively large specific gravity of conventional carbon steel coiled tubing, affected by the weight of the coiled tubing itself, the length of the coiled tubing is restricted. In addition, during the operation of coiled tubing, various surface damages such as scratches, plow marks, and extrusion damages are inevitable, greatly reducing the service life of the coiled tubing. Summary of the Invention

[0005] In order to solve the problems existing in the prior art, embodiments of the present disclosure provide an aluminum alloy strip for coiled tubing, a manufacturing method of coiled tubing, and coiled tubing.

[0006] In view of this, on the one hand, embodiments of the present disclosure provide an aluminum alloy strip for coiled tubing. The alloying elements of the aluminum alloy strip are as follows by mass fraction: 0 < Si ≤ 0.40%, 0 < Fe ≤ 0.50%, 0 < Cu ≤ 0.25%, Mn is 0.60 - 1.20%, Mg is 5.0% - 6.0%, 0 < Cr ≤ 0.25%, Zn is 0.80% - 1.20%, 0 < Ti ≤ 0.20%, Ce is 0.10% - 0.20%, Ta is 0.05% - 0.10%, and the rest is Al.

[0007] On the other hand, embodiments of the present disclosure provide a manufacturing method of coiled tubing. The manufacturing method includes: curling the aluminum alloy strip into coiled tubing; welding the straight weld of the coiled tubing; and performing a spraying treatment on the surface of the coiled tubing.

[0008] In some embodiments, before the aluminum alloy strip is curled and formed into a coiled tubing, the process includes: butting the aluminum alloy strips in sequence.

[0009] In some embodiments, after the aluminum alloy strips are sequentially butt-joined, the method further includes: cleaning the aluminum alloy strips.

[0010] In some embodiments, after cleaning the aluminum alloy strip, the method further includes: cleaning the oxide layer on the surface of the aluminum alloy strip.

[0011] In some embodiments, after welding the straight welds of the coiled tubing, the method further includes: annealing the coiled tubing.

[0012] In some embodiments, after the coiled tubing is annealed, the method further includes: performing a sizing treatment on the coiled tubing.

[0013] In some embodiments, the straight weld of the coiled tubing is welded by one of high-frequency induction welding, laser welding and argon arc welding.

[0014] In some embodiments, in the spraying treatment on the surface of the coiled tubing, the sprayed material is a polyurethane material.

[0015] Another aspect of the disclosed embodiment provides a continuous oil pipe, which is made of the above-mentioned aluminum alloy strip.

[0016] Another aspect of the disclosed embodiments provides a coiled tubing, which is manufactured by any of the manufacturing methods described above.

[0017] The disclosed embodiments optimize the chemical composition of the aluminum alloy strip of the coiled tubing on the one hand, and effectively control and simplify the welding and heat treatment processes of the coiled tubing on the other hand, thereby significantly improving production efficiency. By adding a spraying process, the ability to resist mechanical damage during operation can also be improved, so as to obtain a composite coiled tubing with uniform structure, high strength, good fatigue life, and excellent wear resistance and corrosion resistance.

[0018] In order to make the above-mentioned objectives, features and advantages of the embodiments of the present disclosure more obvious and understandable, preferred embodiments are specifically cited below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In the drawings that are not necessarily drawn to scale, the same reference numerals may describe similar parts in different views. The same reference numerals with letter suffixes or different letter suffixes may represent different instances of similar parts. The drawings generally illustrate various embodiments by way of example and not limitation, and together with the specification and claims, are used to illustrate the disclosed embodiments. When appropriate, the same reference numerals are used throughout the drawings to refer to the same or similar parts. Such embodiments are illustrative and are not intended to be exhaustive or exclusive embodiments of the present apparatus or method. The drawings described herein are used to provide a further understanding of the present disclosure and constitute a part of this application. The illustrative embodiments of the present disclosure and their descriptions are used to explain the present disclosure and do not constitute an improper limitation of the present disclosure. In the drawings:

[0020] Figure 1 It is a schematic diagram of the steps of the method for manufacturing a coiled tubing according to an embodiment of the present disclosure;

[0021] Figure 2 is a schematic flow chart of a method for manufacturing a coiled tubing according to an embodiment of the present disclosure;

[0022] Figure 3 It is a schematic diagram of high-frequency induction welding in the method for manufacturing a coiled tubing according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0023] The specific embodiments of the present disclosure are described in detail below with reference to the accompanying drawings, but are not intended to limit the present disclosure.

[0024] It should be understood that various modifications may be made to the embodiments disclosed herein. Therefore, the above description should not be considered as limiting, but merely as an example of an embodiment. Other modifications within the scope and spirit of the present disclosure will occur to those skilled in the art.

[0025] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present disclosure and, together with the general description of the present disclosure given above and the detailed description of the embodiments given below, serve to explain the principles of the present disclosure.

[0026] These and other characteristics of the present disclosure will become apparent from the following description of a preferred form of embodiment given as a non-limiting example, with reference to the attached drawings.

[0027] It should also be understood that, although the present disclosure has been described with reference to some specific examples, those skilled in the art will be able to realize many other equivalent forms of the present disclosure that have the features described in the claims and are therefore within the scope of protection defined thereby.

[0028] The above and other aspects, features and advantages of the present disclosure will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

[0029] Specific embodiments of the present disclosure are described hereinafter with reference to the accompanying drawings; however, it should be understood that the disclosed embodiments are merely examples of the present disclosure, which may be implemented in a variety of ways. Well-known and / or repeated functions and structures are not described in detail to avoid obscuring the present disclosure with unnecessary or redundant details. Therefore, the specific structural and functional details disclosed herein are not intended to be limiting, but merely serve as a basis and representative basis for the claims to teach those skilled in the art to use the present disclosure in a variety of ways with substantially any suitable detailed structure.

[0030] It should be noted that the terms "first", "second", etc. in the specification and claims of the present disclosure and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present disclosure described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products, or devices.

[0031] This specification may use the phrases "in one embodiment," "in another embodiment," "in a further embodiment," or "in other embodiments," all of which may refer to one or more of the same or different embodiments according to the present disclosure.

[0032] The first embodiment of the present disclosure provides a method for manufacturing a coiled tubing, through which the coiled tubing can be manufactured. Figure 1 Combined with Figure 2 As shown, the method for manufacturing the coiled tubing includes:

[0033] S101, rolling the aluminum alloy strip into a continuous oil pipe.

[0034] In this step, the aluminum alloy strip is rolled and formed into a coiled tubing. The coiled tubing of this embodiment is made of aluminum alloy material, which has the characteristics of high specific strength and good corrosion resistance, and is widely used in industries such as petrochemical, aerospace, transportation and construction.

[0035] Before the aluminum alloy strip is rolled and formed into a continuous oil pipe, the aluminum alloy strips are butt-jointed in sequence. Specifically, the aluminum alloy strips are generally plate-shaped or sheet-shaped. According to the length requirement of the continuous oil pipe (for example, generally up to several thousand meters), the number of aluminum alloy strips needs to be determined according to the length requirement and based on the size of the aluminum alloy strips, and then a plurality of the aluminum alloy strips are butt-jointed in sequence by, for example, welding. The welding method used here is, for example, plasma welding, argon arc welding, or laser welding. Specifically, a plurality of the aluminum alloy strips can be welded to each other by 45° plasma and butt welding to achieve overall lengthening.

[0036] The butt welding operation of the aluminum alloy strip needs to be performed under the protection of an inert gas, which may be argon or a mixture of argon and helium. The oxygen concentration can be strictly controlled by inputting the inert gas during the welding process, for example, the measured value of the oxygen concentration can be maintained at a level less than 5%.

[0037] In addition, after the aluminum alloy strips are butt-joined in sequence, the method further includes: cleaning the aluminum alloy strips. Specifically, after the aluminum alloy strips are butt-joined and lengthened, the aluminum alloy strips are passed through a steel strip cleaning machine, so that the steel strip cleaning machine cleans and removes impurities such as oil stains on the surface of the butt-joined aluminum alloy strips, thereby ensuring that the surface of the aluminum alloy strips is clean. The cleaning liquid used in the steel strip cleaning machine is a mixed solution prepared by NaOH (400-500 g / L) and NaNO2 (100-150 g / L), and the cleaning of the aluminum alloy strips needs to be carried out within a temperature range of 100-120°C.

[0038] In addition, after the aluminum alloy strip is cleaned, the method further includes: cleaning the oxide layer on the surface of the aluminum alloy strip. Specifically, after cleaning the oil and impurities on the surface of the aluminum alloy strip, the oxide layer on the surface of the aluminum alloy strip can be cleaned by laser polishing or manual polishing. The cleaning range of the surface of the aluminum alloy strip needs to be 15-20 mm away from the docking position on the aluminum alloy strip, and the polishing depth needs to reach 0.03-0.05 mm.

[0039] In this step, after the aluminum alloy strip after docking has been tested and qualified, the aluminum alloy strip is rolled onto a steel strip roller. Specifically, the aluminum alloy strip that is several thousand meters long after docking is transferred to the steel strip roller of the pipe making unit, and the aluminum alloy strip is gradually bent and formed through the rotation of the steel strip roller. The steel strip roller here can adopt a copper roller structure, and by adopting the copper roller, a good surface quality can be obtained for the aluminum alloy continuous oil pipe.

[0040] S102, welding the straight welds of the coiled tubing.

[0041] After the aluminum alloy strip is rolled and formed into a coiled tubing in step S101, in this step, the straight weld of the coiled tubing is welded. Specifically, in this step, the straight weld forming the coiled tubing refers to the joint position formed by the bending of the coiled tubing. When welding the straight weld at the joint position, one of high-frequency induction welding, laser welding and argon arc welding can be used. Among them, high-frequency induction welding is preferably used, which can obtain the best welding quality.

[0042] In this embodiment, the welding of aluminum alloy coiled tubing is continuously achieved by a high-frequency induction welding device.

[0043] like Figure 3 As shown, the high-frequency induction welding device here generally includes an induction coil 20. During the welding process using the high-frequency induction welding device, the induction frequency is 280-370KHZ, the welding power is 80-120KW, and the welding speed is 25-40m / min.

[0044] During high-frequency induction welding, according to the electromagnetic induction characteristics of the material used for the coiled tubing, the gap t between the induction coil 20 and the coiled tubing 10 is controlled to be set to t≤9mm, while the angle α of the welded V-shaped opening 30 is maintained between 8° and 10°. The roller gap is controlled to ensure the stability of the V-shaped opening 30 during welding. Preferably, during the welding process, the coiled tubing can also be squeezed by a welding squeezing roller to form uniform internal burrs.

[0045] In addition, during the welding process, argon gas protection is required for welds, V-shaped openings and other locations to ensure good straight weld performance.

[0046] The disclosed embodiment adopts high-frequency induction welding to manufacture aluminum alloy coiled tubing, and has a forming process, welding process and heat treatment process that meet the performance requirements. In addition, by reasonably controlling the extrusion force and pipe making speed of the unit during the forming process, the strength of the coiled tubing is improved through deformation strengthening; it is also necessary to set key welding process parameters and heat treatment process parameters to obtain an aluminum alloy coiled tubing with uniform and consistent structures of the weld, parent material and heat-affected zone.

[0047] After step S102, the method further includes: annealing the coiled tubing.

[0048] In this step, the coiled tubing welded by the straight weld is heated by an induction heating furnace to achieve annealing. Specifically, the coiled tubing is heated to a temperature range of 200°C-280°C for full tube annealing of the coiled tubing, thereby reducing deformation stress during forming and welding. In addition, a protective gas may be introduced during the annealing process, for example, the gas flow rate in the tube body of the coiled tubing is controlled within the range of 12-15L / min to prevent high-temperature oxidation of the inner wall of the coiled tubing.

[0049] After the annealing treatment is completed, the method further includes: performing sizing treatment on the coiled tubing.

[0050] In this step, the coiled tubing is subjected to a sizing treatment. Specifically, the coiled tubing after the annealing treatment is cooled to a surface temperature of 100-150° C. by, for example, an air-cooling bracket, and then the coiled tubing is input into a sizing unit. The sizing unit is used to obtain the required outer diameter of the coiled tubing, and finally the coiled tubing with good structural properties and meeting the size requirements can be obtained.

[0051] S103, spraying the surface of the coiled tubing.

[0052] After the straight weld of the coiled tubing is welded in the above step S102, in this step, the surface of the coiled tubing is sprayed. Here, before the surface of the coiled tubing is sprayed, it includes: cleaning the oxide layer on the surface of the coiled tubing. The surface of the coiled tubing that has been completed is treated, for example, the oxide layer on the surface of the coiled tubing is removed by using a grinding and polishing device, and the roughness of the surface of the coiled tubing is ensured to be within the range of Ra10-25μm, which helps to improve the bonding strength between the surface of the coiled tubing and the coating in the subsequent process.

[0053] After the surface treatment of the coiled tubing, a wear-resistant and corrosion-resistant spray glue is sprayed on the surface of the coiled tubing. After the spraying treatment is completed, an aluminum alloy coiled tubing is finally obtained. The sprayed material here is a polyurethane material. It should be noted that the spraying treatment here needs to be carried out at room temperature, and the coating thickness after spraying reaches 0.15-0.25mm.

[0054] By spraying a wear-resistant and corrosion-resistant coating on the surface of the coiled tubing after the tubing is made, the corrosion resistance of the outer surface of the coiled tubing can be further improved, and the wear resistance and mechanical damage resistance of the outer surface of the coiled tubing can also be improved. Among them, the oxygen corrosion resistance of the aluminum alloy coiled tubing made in the embodiment of the present disclosure is more than 4 times that of the conventional coiled tubing.

[0055] The following further elaborates in detail on the manufacturing method of the coiled tubing involved in the embodiments of the present disclosure in combination with specific implementation manners:

[0056] The aluminum alloy strip is welded by means of plasma welding / gas tungsten arc welding / laser welding, etc. under the protection of inert gas through butt welding at 45°. Then the aluminum alloy strip is butt-welded to a predetermined length, and then the aluminum alloy strip is transferred to a pipe-making unit, and the aluminum alloy strip is continuously passed through a forming unit and gradually bent into shape. Then, by means of high-frequency induction welding or laser welding or gas tungsten arc welding and in cooperation with the extrusion of a welding extrusion roll, the welding of the coiled tubing is continuously completed by adjusting the welding machine power and the welding speed (the welding process is referred to Table 1). After welding is completed, the coiled tubing is annealed (the annealing process parameters are shown in Table 1) to make the microstructure and properties of the inclined weld, straight weld and base material of the coiled tubing tend to be consistent, and improve the comprehensive performance of the whole pipe.

[0057] Finally, the surface of the coiled tubing is treated by mechanical polishing, and primer and topcoat are sprayed at normal temperature, and finally an aluminum alloy composite coiled tubing with high strength, excellent wear resistance and corrosion resistance, etc., and suitable for oxygen corrosion and high well-depth working environments is obtained.

[0058] Table 1. Key process parameters in the specific implementation process

[0059]

[0060] The aluminum alloy composite coiled tubing formed by the embodiments of the present disclosure has characteristics such as high strength, excellent wear resistance and corrosion resistance, etc., and is suitable for working environments with oxygen corrosion and high well depth.

[0061] The second embodiment of the present disclosure provides a coiled tubing, which is manufactured by the manufacturing method of the first embodiment above. The weld, heat affected zone and base material of the coiled tubing in this embodiment have high strength with uniform microstructure and properties. The aluminum alloy composite coiled tubing formed by the embodiments of the present disclosure has characteristics such as high strength, excellent wear resistance and corrosion resistance, etc., and is suitable for working environments with oxygen corrosion and high well depth.

[0062] The third embodiment of the present disclosure provides an aluminum alloy strip for coiled tubing. The aluminum alloy strip here can be used to manufacture the coiled tubing by the manufacturing method of the first embodiment. The coiled tubing made of the aluminum alloy strip in this embodiment has characteristics such as high strength, excellent wear resistance and corrosion resistance, etc. Specifically, the alloying elements of the aluminum alloy strip of the coiled tubing are as follows by mass fraction: 0 < Si (silicon) ≤ 0.40%, 0 < Fe (iron) ≤ 0.50%, 0 < Cu (copper) ≤ 0.25%, Mn (manganese) is 0.60 - 1.20%, Mg (magnesium) is 5.0% - 6.0%, 0 < Cr (chromium) ≤ 0.25%,

[0063] Zn (zinc) is 0.80% - 1.20%, 0 < Ti (titanium) ≤ 0.20%, Ce (cerium) is 0.10% - 0.20%, Ta (tantalum) is 0.05% - 0.10%, and the balance is Al (aluminum).

[0064] Of course, in some other embodiments, it may also include Zr (zirconium) with a mass fraction of 0.05% - 0.25% to improve corrosion resistance and wear resistance. In addition, it also includes trace and inevitable impurities.

[0065] Three specific examples are provided below. Their chemical compositions are as shown in Table 2 below by mass fraction:

[0066] Table 2. Specific chemical compositions in the aluminum alloy strip (% )

[0067] Examples Si Fe Cu Mn Mg Cr Zn Ti Ce Ta 1 0.38 0.25 0.24 0.62 5.20 0.25 0.82 0.16 0.10 0.05 2 0.35 0.31 0.22 0.83 5.50 0.25 1.01 0.18 0.15 0.08 3 0.37 0.22 0.23 1.11 6.00 0.25 1.18 0.18 0.16 0.1

[0068] Specifically, in the chemical composition of the aluminum alloy strip of the coiled tubing, by adding Ce and Ta elements, an excess phase with better thermal stability can be formed, improving the tensile strength and corrosion resistance of the aluminum alloy material in a continuous high-temperature and high-pressure environment. In addition, adding Ta element can improve the high-temperature corrosion resistance.

[0069] Furthermore, in the chemical composition of the aluminum alloy strip of the coiled tubing, the content of Zn element is significantly increased compared with the existing content, thereby improving the strength and hardness of the aluminum alloy strip. Here, the Zn element and the Mg element form a strengthening phase, which can further improve the performance of the aluminum alloy strip.

[0070] The embodiments of the present disclosure optimize the chemical composition of the aluminum alloy strip, improve the strength and high-temperature stability of the aluminum alloy strip, and extend the service life of the coiled tubing, especially improving the operation safety when applied to high-pressure deep well operations.

[0071] Based on different chemical compositions and with a wear-resistant and corrosion-resistant coating on the surface, the mechanical properties of the coiled tubing meet the requirements of 70-grade coiled tubing. The parameters are shown in Table 3. For example, the yield strength reaches 485 - 520 Mpa, the tensile strength reaches 600 - 650 MPa, the plastic elongation rate is greater than 12%, and the hardness is 18 HRC - 22 HRC. In addition, the wear-resistant effect parameters of the coiled tubing in the sand washing wear test are shown in Table 4, and its corrosion resistance in the oxygen corrosion environment is better than that of carbon steel materials. The specific effect parameters are shown in Table 5. Here, the comparative examples use 90-grade carbon steel tubing and 2205 tubing, and their compositions are shown in Table 6.

[0072] Table 3. Mechanical property parameters of different examples

[0073] Examples tensile strength Yield Strength Elongation 1 607Mpa 485Mpa 15％ 2 613Mpa 491Mpa 15％ 3 622Mpa 502Mpa 14％

[0074] Table 4. Comparison of sand washing and wear test of coiled tubing in Example 1

[0075]

[0076] Table 5. Comparison of oxygen corrosion test results of coiled tubing in Example 1

[0077]

[0078] Table 6. Chemical composition of comparative examples (%)

[0079] contrast C Si Mn Cr Mo 90 grade oil pipe 0.12 0.42 0.74 - - 2205 Oil Pipe 0.018 0.25 1.33 22.4 2.82

[0080] The fourth embodiment of the present disclosure provides a coiled tubing, which is made of the above-mentioned aluminum alloy strip. The aluminum alloy composite coiled tubing formed in the embodiment of the present disclosure has the characteristics of high strength, excellent wear resistance and corrosion resistance, and is suitable for oxygen corrosion and high well depth working environment.

[0081] The disclosed embodiments optimize the chemical composition of the aluminum alloy strip of the coiled tubing on the one hand, and effectively control and simplify the welding and heat treatment processes of the coiled tubing on the other hand, thereby significantly improving production efficiency. By adding a spraying process, the ability to resist mechanical damage during operation can also be improved, so as to obtain a composite coiled tubing with uniform structure, high strength, good fatigue life, and excellent wear resistance and corrosion resistance.

[0082] In the above embodiments of the present disclosure, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0083] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" may include both "above" and "below". The device may also be positioned in other different ways, rotated 90 degrees or in other orientations, and the spatially relative descriptions used herein are interpreted accordingly.

[0084] In addition to the above, it should be noted that "one embodiment", "another embodiment", "embodiment", etc. mentioned in this specification refer to the specific features, structures or characteristics described in conjunction with the embodiment included in at least one embodiment generally described in this application. The same expression appearing in multiple places in the specification does not necessarily refer to the same embodiment. Further, when describing a specific feature, structure or characteristic in conjunction with any embodiment, it is claimed that the realization of such feature, structure or characteristic in conjunction with other embodiments also falls within the scope of the present disclosure.

[0085] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0086] The above description is only a preferred embodiment of the present disclosure and is not intended to limit the present disclosure. For those skilled in the art, the present disclosure may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. An aluminum alloy strip for a coiled tubing, characterized in that: The alloying elements of the aluminum alloy strip are as follows by mass fraction: 0 < Si ≤ 0.40%, 0 < Fe ≤ 0.50%, 0 < Cu ≤ 0.25%, Mn is 0.60 - 1.20%, Mg is 5.0% - 6.0%, 0 < Cr ≤ 0.25%, Zn is 0.80% - 1.20%, 0 < Ti ≤ 0.20%, Ce is 0.10% - 0.20%, Ta is 0.05% - 0.10%, and the balance is Al.

2. A method for manufacturing a coiled tubing, characterized in that: The manufacturing method includes: Curling the aluminum alloy strip to form a coiled tubing; Welding the straight weld of the coiled tubing; Performing a spraying treatment on the surface of the coiled tubing.

3. The method for manufacturing a coiled tubing according to claim 2, characterized in that: Before curling the aluminum alloy strip to form a coiled tubing, it includes: Successively butting the aluminum alloy strips.

4. The method for manufacturing a coiled tubing according to claim 3, characterized in that: After successively butting the aluminum alloy strips, it further includes: Cleaning the aluminum alloy strip.

5. The method for manufacturing a coiled tubing according to claim 4, characterized in that: After cleaning the aluminum alloy strip, it further includes: Removing the oxide layer on the surface of the aluminum alloy strip.

6. The method for manufacturing a coiled tubing according to claim 2, characterized in that: After welding the straight weld of the coiled tubing, it further includes: Annealing the coiled tubing.

7. The method for manufacturing a coiled tubing according to claim 6, characterized in that: After annealing the coiled tubing, it further includes: Sizing the coiled tubing.

8. The method for manufacturing a coiled tubing according to claim 6, characterized in that: One of high-frequency induction welding, laser welding, and TIG welding is used for welding the straight weld of the coiled tubing.

9. The method for manufacturing a coiled tubing according to claim 6, characterized in that: In the spraying treatment on the surface of the coiled tubing, the spraying material is a polyurethane-based material.

10. A coiled tubing, characterized in that: Manufactured using the aluminum alloy strip described in claim 1.

11. A coiled tubing, characterized in that: Manufactured by the manufacturing method described in any one of claims 2 - 9.

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