Manufacturing method of anti-corrosion metallurgical composite pipe and composite pipe

Abstract

The invention discloses a manufacturing method of a corrosion-resistant metallurgical composite pipe, which comprises the following steps: cladding alloy spherical powder on the inner wall of a base pipe by adopting a laser cladding process to form a cladding layer, and the laser spot adopted by the laser cladding process is a rectangular spot and the laser power is 6-20kW; and after cladding is completed, a threaded connector is machined at the pipe end. The manufacturing method disclosed by the invention is simple and convenient to implement and relatively low in production cost, and has a good market prospect.

Description

Technical Field

[0001] The invention relates to a method for manufacturing a steel pipe, in particular to a method for manufacturing a composite pipe. Background Art

[0002] The working environment of compressed air energy storage has the characteristics of high oxygen content, high humidity, and high mineralization. Under such conditions, carbon steel, low alloy steel, and even some stainless steel will suffer extremely severe uniform corrosion and local corrosion when used as injection and production pipes. The corrosion rate of carbon steel or low alloy steel in underground compressed air energy storage conditions is as high as 2-10mm / y. The use of such materials to produce injection and production pipes will face the problem of frequent shutdown, maintenance, and replacement.

[0003] Based on this, the existing technology uses corrosion-resistant coating + low-alloy steel pipe to produce compressed air energy storage pipes, but the coating is prone to large-scale shedding under air flow. In addition, there is a difference in the elastic modulus of the coating and the pipe body, and large pressure fluctuations during high-pressure air injection and production can easily cause the two to separate.

[0004] Another solution is to safely use corrosion-resistant pure materials such as nickel-based alloys as injection and production pipes, but the cost of such pipes is extremely high.

[0005] Based on this, it is expected to obtain a metallurgical composite pipe for compressed air energy storage, which can give full play to the mechanical properties of the base pipe and the corrosion resistance of the alloy layer, while greatly reducing the cost. Summary of the invention

[0006] One of the purposes of the present invention is to provide a method for manufacturing a corrosion-resistant metallurgical composite pipe. The manufacturing method manufactures a metallurgical composite smooth pipe by cladding a corrosion-resistant alloy on the inner wall of a base pipe through a laser cladding process, and processes a threaded joint at the end of the composite pipe after cladding to ensure that the shoulders of the internal and external threaded joints face each other after buckling, so that corrosive media cannot directly invade the internal structure such as the sealing surface.

[0007] In order to achieve the above object, the present invention proposes a method for manufacturing a corrosion-resistant metallurgical composite pipe, which comprises the following steps:

[0008] The alloy spherical powder is clad on the inner wall of the base tube by a laser cladding process to form a cladding layer, wherein the laser spot used in the laser cladding process is a rectangular spot and the laser power is 6-20kW.

[0009] After cladding is completed, threaded joints are machined on the pipe ends.

[0010] Laser cladding technology has a wide range of material selection, dense cladding structure, and little damage to the substrate. In particular, the cladding layer is very thin, so a large amount of expensive corrosion-resistant alloys can be saved. In addition, it can also achieve complete metallurgical bonding with the substrate to ensure safety over a long service life.

[0011] Compressed air energy storage has requirements for gas flux, so a larger diameter injection and production pipe is often used. The inventors found through research that the current conventional laser cladding process, such as using a circular spot of φ3-5mm, a laser power of 2-4kW, a line speed of 2000-4000mm / min, and an overlap rate of 40%-70%, cannot efficiently manufacture corrosion-resistant metallurgical composite pipes.

[0012] In order to improve manufacturing efficiency, the manufacturing method of the present invention creatively proposes to use a rectangular laser spot, which can cover a larger area during cladding, thereby improving efficiency. At the same time, the present invention increases the laser power to 6-20kW in order to ensure the laser energy density in conjunction with the larger spot area.

[0013] In the manufacturing method of the present invention, the threaded joint is processed on the pipe end after the cladding is completed. The internal and external threaded joint requires that the shoulder surface of the back end should be aligned after the buckle is made, so that it has a certain contact stress to ensure that the corrosive medium cannot directly invade the internal structure such as the sealing surface.

[0014] Furthermore, in the manufacturing method described in the present invention, the outer diameter of the base pipe is 139.7-711.2 mm.

[0015] Furthermore, in the manufacturing method of the present invention, the particle size of the alloy spherical powder is 50-200 μm.

[0016] Furthermore, in the manufacturing method described in the present invention, the rectangular spot used in laser cladding has a length of 10-60 mm and a width of 1-7 mm.

[0017] Furthermore, in the manufacturing method described in the present invention, the cladding line speed of laser cladding is 200-2000 mm / min.

[0018] Furthermore, in the manufacturing method of the present invention, the overlap rate of laser cladding is 5%-40%.

[0019] Furthermore, in the manufacturing method of the present invention, during the laser cladding process, the powder feeding speed of the alloy spherical powder is controlled to be 30-300 g / min.

[0020] Furthermore, in the manufacturing method of the present invention, the thickness of the cladding layer is 0.3-1.3 mm, and the dilution rate is 1-5 wt %.

[0021] Furthermore, in the manufacturing method described in the present invention, the material of the alloy spherical powder is selected from: duplex stainless steel, austenitic stainless steel or nickel-based alloy.

[0022] Correspondingly, another object of the present invention is to obtain a corrosion-resistant metallurgical composite pipe, which has corrosion resistance under underground compressed air energy storage conditions and can also ensure considerable mechanical properties through the base pipe, while significantly reducing costs.

[0023] Based on the above objectives, the present invention also provides a corrosion-resistant metallurgical composite pipe, which is manufactured by the manufacturing method described above.

[0024] The method for manufacturing the corrosion-resistant metallurgical composite pipe of the present invention has the following advantages and beneficial effects:

[0025] The corrosion-resistant metallurgical composite pipe produced by the manufacturing method of the present invention has an outer diameter that can cover large-diameter pipes of 139.7-711.2 mm, and thus can meet the large-flow injection and production requirements of underground compressed air energy storage.

[0026] The corrosion-resistant metallurgical composite pipe manufactured by the manufacturing method of the present invention has a corrosion resistance that reaches the level of similar cladding corrosion-resistant alloys during its entire life cycle, and its mechanical properties meet the API 5CT requirements.

[0027] The corrosion-resistant metallurgical composite pipe manufactured by the manufacturing method of the present invention has a cladding layer that is completely metallurgically bonded to the base pipe, thereby ensuring that no peeling or delamination occurs during the service life cycle.

[0028] The cost of the corrosion-resistant metallurgical composite pipe produced by the manufacturing method of the present invention is only 1 / 3-1 / 2 of the same specification and same type of pure corrosion-resistant alloy pipe, thus having good economic benefits. DETAILED DESCRIPTION

[0029] The following will further explain and illustrate the method for manufacturing the corrosion-resistant metallurgical composite pipe and the composite pipe of the present invention in combination with specific embodiments, but such explanation and illustration do not constitute an improper limitation on the technical solution of the present invention.

[0030] In order to further illustrate the superiority of the method for manufacturing the corrosion-resistant metallurgical composite pipe, the inventors designed and specifically implemented the following Examples 1-6 and Comparative Examples 1-3 to illustrate the present invention.

[0031] In each embodiment of the present invention, steel pipes of different steel grades and outer diameters are used as base pipes, and different corrosion-resistant alloys are used as cladding layer materials, and the corrosion-resistant alloys are all made into spherical powders with a particle size range of 50-200 μm. Table 1 lists the base pipe steel grade, base pipe outer diameter, cladding layer alloy powder material, and alloy spherical powder particle size of each embodiment.

[0032] Table 1.

[0033]

[0034]

[0035] Comparative Examples 1-3 use alloy pipes without a cladding layer to directly process threaded joints on the pipe ends, and their steel grades and types correspond to those of Examples 2, 4, and 5, respectively. Table 2 lists the specific material selection information of each comparative example.

[0036] Table 2.

[0037]

[0038] In Examples 1-6 of the present invention, the alloy spherical powder is clad on the inner wall of the substrate tube by laser cladding process under the protection of inert gas to form a cladding layer.

[0039] In each embodiment of the present invention, the laser spot used in the laser cladding process is a rectangular spot, the length of the rectangular spot is 10-60 mm, the width is 1-7 mm, the laser power used to control the laser cladding is 6-20 kW, the cladding line speed is 200-2000 mm / min, the overlap rate is 5%-40%, and the powder feeding speed of the alloy spherical powder is 30-300 g / min.

[0040] Table 3 lists the manufacturing process parameters of the corrosion-resistant metallurgical composite pipes of Examples 1-6.

[0041] Table 3.

[0042]

[0043]

[0044] Note: The spot size data in Table 3 is the length of the rectangular spot * the width of the rectangular spot.

[0045] Based on Examples 1-6 of the present invention, sampling was performed, and the samples were cut into full-wall thickness pipe bodies, and the exposed base pipe was sealed with epoxy resin to expose the cladding layer. The cladding layer information was calculated and observed and listed in Table 4.

[0046] Table 4 lists the cladding layer thickness and cladding layer dilution rate of the corrosion-resistant metallurgical composite pipes of Examples 1-6.

[0047] Table 4.

[0048]

[0049] After the cladding is completed, a threaded joint is processed on the pipe end of Example 1-6 to ensure that the shoulder of the internal and external threaded joint faces the top after buckling, so that it has a certain contact stress to ensure that the corrosive medium cannot directly invade the internal structure such as the sealing surface, and finally form a corrosion-resistant metallurgical composite pipe.

[0050] The corrosion-resistant metallurgical composite pipes of Examples 1-6 and the comparative pipes of Comparative Examples 1-3 were sampled respectively, and their mechanical properties were tested. The obtained mechanical properties test results are listed in Table 5. Among them, the relevant performance tests include:

[0051] Room temperature tensile test: According to GB / T 228.1-2010 Tensile test of metallic materials Part 1: Room temperature tensile test method, the yield strength, tensile strength and elongation of the samples of Examples 1-6 and Comparative Examples 1-3 at room temperature were obtained.

[0052] V-notch Charpy impact test: According to GB / T 229-2020 Charpy Pendulum Impact Test Method for Metallic Materials, a full-size specimen of 10×10×55 mm is used to detect the impact performance AKV, i.e., impact energy KV2, of the specimens of Examples 1-6 and Comparative Examples 1-3.

[0053] Table 5.

[0054]

[0055] It can be seen from Table 5 that the mechanical properties of the samples of each embodiment of the metallurgical composite pipe prepared by the manufacturing method of the present invention meet the requirements of the API standard, and are in the same range as the mechanical properties of the comparative pipe of the same steel grade.

[0056] In addition, typical underground compressed air energy storage conditions were simulated to test the corrosion resistance of each embodiment and comparative example.

[0057] The medium is 230g / L NaCl solution, and the compressed air pressure is controlled to 8-35MPa, the temperature is controlled to 20℃-100℃, and the compressed air flow rate is controlled to 1.5m / s. According to "ASTM G111-21 Standard Guide for Corrosion Tests in High Temperature or High Pressure Environment, or Both" and "JB / T 7901-1999 Metal Materials Laboratory Uniform Corrosion Full Immersion Test Method", the average corrosion rate and maximum pitting rate of the sample are tested. The test data obtained are listed in Table 6.

[0058] Table 6

[0059]

[0060]

[0061] It can be seen from Table 6 that under typical underground compressed air energy storage conditions, the uniform corrosion rate of the corrosion-resistant metallurgical composite pipe for underground compressed air energy storage prepared by the present invention is less than 0.025 mm / y, the degree of corrosion is mild, and no obvious pitting is observed, which is equivalent to the corresponding pure corrosion-resistant alloy pipe (i.e., the comparative pipe) under the same conditions.

[0062] It can be seen that the mechanical properties of the corrosion-resistant metallurgical composite pipe produced by the present invention meet the API 5CT standard, and the corrosion resistance meets the standard requirements and reaches the level of the corresponding pure corrosion-resistant alloy pipe, while the cost is only 1 / 3-1 / 2 of the corresponding pure corrosion-resistant alloy pipe of the same specification that can be manufactured. The corrosion-resistant metallurgical composite pipe manufactured by this process can meet the requirements of underground compressed air energy storage injection and production, and has a huge market prospect.

[0063] It should be noted that the combination of the various technical features in this case is not limited to the combination described in the claims of this case or the combination described in the specific embodiments. All technical features recorded in this case can be freely combined or combined in any way unless there is a contradiction between them.

[0064] It should also be noted that the above-listed embodiments are only specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and similar changes or modifications made therewith can be directly derived or easily associated with the contents disclosed by those skilled in the art from the present invention, and all should belong to the protection scope of the present invention.

Claims

1. A method for manufacturing a corrosion-resistant metallurgical composite pipe, characterized in that: Includes steps: The alloy spherical powder is clad on the inner wall of the substrate tube by a laser cladding process to form a cladding layer, wherein the laser spot used in the laser cladding process is a rectangular spot and the laser power is 6-20kW; After cladding is completed, threaded joints are machined on the pipe ends.

2. The manufacturing method according to claim 1, characterized in that The outer diameter of the base pipe is 139.7-711.2 mm.

3. The manufacturing method according to claim 1, characterized in that: The particle size of the alloy spherical powder is 50-200 μm.

4. The manufacturing method according to claim 1, characterized in that: The rectangular light spot has a length of 10-60 mm and a width of 1-7 mm.

5. The manufacturing method according to claim 1, characterized in that: The cladding line speed of laser cladding is 200-2000mm / min.

6. The manufacturing method according to claim 1, characterized in that: The overlap rate of laser cladding is 5%-40%.

7. The manufacturing method according to claim 1, characterized in that: During the laser cladding process, the feeding speed of the alloy spherical powder is controlled to be 30-300 g / min.

8. The manufacturing method according to claim 1, characterized in that: The thickness of the cladding layer is 0.3-1.3 mm, and the dilution rate is 1-5 wt %.

9. The manufacturing method according to claim 1, characterized in that: The material of the alloy spherical powder is selected from: austenitic stainless steel, duplex stainless steel or nickel-based alloy.

10. A corrosion-resistant metallurgical composite pipe, characterized in that: The method is prepared by the method according to any one of claims 1 to 9.

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