Method and apparatus for progressive straightening and strengthening of subsea pipeline pipe

Abstract

The application provides a progressive correction and reinforcement method and device for a submarine pipeline pipe, and the specific steps are as follows: determining the diameter reduction rate of the pipeline pipe to be corrected and the radius of the diameter reduction die; four diameter reduction dies compress the pipeline pipe to be corrected under the action of a universal press, the correction in the L' length range is completed, and the correction of the full length size of the pipeline pipe to be corrected is progressively completed; the straightness and the ovality of the pipeline pipe after correction are measured; the change of the residual stress is analyzed through a cutting experiment; and the change of the hoop compressive yield strength is analyzed through a compression experiment. The application corrects the straightness and the ovality of the pipeline pipe, improves the hoop compressive yield strength of the pipeline pipe, reduces the hoop residual stress, improves the pressure collapse resistance and the service depth, the pipeline pipe after correction is subjected to low-temperature heat treatment, the hoop compressive yield strength and the pressure collapse resistance are further improved without affecting the geometric shape, and the application is particularly suitable for the correction and pressure collapse resistance performance reinforcement of the oil and gas pipeline pipe in a deep sea environment.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of large-scale straight seam welded pipe manufacturing, in particular to a progressive shaping and strengthening method and device for submarine pipeline pipes. BACKGROUND

[0002] Oil and gas backbone transmission pipelines mainly use large-scale straight seam submerged arc welded pipes. In order to meet the laying standard requirements of the pipeline pipes, geometric shape shaping is a key process for improving the straightness and ellipticity of the formed straight seam welded pipes. The traditional pipeline pipes mostly use the expanding shaping process. Influenced by the Bauschinger effect of the metal material, the expanding shaping process increases the hoop tensile yield strength of the pipeline pipe, but to some extent, reduces the hoop compressive yield strength. Compared with the expanding shaping process, the reducing shaping process improves the geometric size precision of the pipeline pipe, reduces and homogenizes the residual stress, and at the same time, increases the hoop compressive yield strength of the pipeline pipe, and improves the anti-collapse performance of the pipeline pipe. Since the service environment of the deep-sea submarine pipeline pipe is more complex, it needs to bear a higher external pressure load. Therefore, compared with the expanding shaping, the reducing shaping process is more suitable for the geometric shape shaping of the deep-sea pipeline pipe.

[0003] In summary, the present application provides a progressive shaping and strengthening method and device for submarine pipeline pipes, which improves the straightness and ellipticity of the pipeline pipe, at the same time, reduces and homogenizes the residual stress distribution of the pipeline pipe, improves the hoop compressive yield strength of the pipeline pipe, improves the anti-collapse performance and service depth of the pipeline pipe, and is particularly suitable for the geometric shape shaping and anti-collapse performance strengthening of the deep-sea pipeline pipe. SUMMARY

[0004] In view of the problems existing in the prior art, the present application provides a progressive shaping and strengthening method and device for submarine pipeline pipes, according to the initial parameters of the pipeline pipe to be shaped and the tonnage of the press, the reducing rate, the single shaping length of the pipeline pipe to be shaped, the curvature radius of the reducing die and the loading displacement of the press are determined respectively, the single shaping length feeding of the pipeline pipe to be shaped is completed by the roller, the loading displacement of the press is controlled to realize the synchronous compression of the upper reducing die, the right reducing die, the left reducing die and the lower reducing die in four different directions, the press moves to the initial position, the spring rebounds, and the reducing shaping of the single shaping length of the pipeline pipe to be shaped is completed, the process is repeated until the reducing shaping of the full-length size of the pipeline pipe to be shaped is completed, the ellipticity and straightness of the pipeline pipe after reducing shaping are improved, the residual stress is reduced and uniformly distributed, the hoop compressive yield strength is improved, and the anti-collapse performance and service depth are improved.

[0005] The present application provides a progressive shaping and strengthening method for submarine pipeline pipes, and the specific implementation steps are as follows:

[0006] S1, according to the initial parameters of the pipeline to be calibrated, the curvature radius of the required reducing die of the pipeline to be calibrated is calculated, and the expression of the curvature radius of the reducing die is as follows:

[0007]

[0008] Wherein, R0 is the curvature radius of the reducing die, δ is the reducing rate of the pipeline to be calibrated, and L0 is the initial circumference of the pipeline to be calibrated;

[0009] S2, the single calibration length L' of the pipeline to be calibrated is determined, the pipeline to be calibrated is fed into the reducing calibration device by the roller at the feeding length L', and reducing calibration is carried out, and the specific operation process is as follows:

[0010] S21, the press is started to move vertically towards the pipeline to be calibrated, under the action of the press, the upper reducing die and the lower reducing die compress the pipeline to be calibrated in the vertical direction, the right reducing die and the left reducing die move along the slide rail in the U-shaped frame respectively, the right reducing die and the left reducing die compress the pipeline to be calibrated in the horizontal direction, when the loading displacement of the press is H, the centers of the upper reducing die, the lower reducing die, the right reducing die and the left reducing die coincide, at this time, the press is closed, and the expression of the loading displacement of the press is as follows:

[0011]

[0012] Wherein, a is the major axis length of the pipeline to be calibrated, b is the minor axis length of the pipeline to be calibrated, L0 is the initial circumference of the pipeline to be calibrated, and R0 is the curvature radius of the reducing die;

[0013] S22, the press is started to move away from the pipeline to be calibrated to the initial position, at this time, the spring rebounds, and the reducing calibration of the L' length of the pipeline to be calibrated is completed;

[0014] S3, the step S2 is repeated until the reducing calibration of the full length size of the pipeline to be calibrated is completed;

[0015] S4, taking the inner arch center of the two end faces of the pipeline after reducing calibration as the reference line, the distance between the inner arch line of the pipeline after reducing calibration and the reference line is measured, and the straightness of the pipeline after reducing calibration is calculated, and the expression of the straightness is as follows:

[0016]

[0017] Wherein, l max is the farthest distance between the inner arch line and the reference line, and L is the length of the pipeline to be calibrated;

[0018] S5, measuring the ellipticity of the pipeline pipe after the diameter reduction and the shape correction in the hoop section by using a three-coordinate measuring instrument, measuring once every certain distance to obtain the ellipticity of the pipeline pipe at different positions after the diameter reduction and the shape correction;

[0019] S6, cutting a pipe blank N1 of a certain length on the pipeline pipe to be corrected, cutting two pipe blanks N2 and N3 of equal length on the pipeline pipe after the diameter reduction and the shape correction, and performing heat treatment on the pipe blank N3;

[0020] S7, cutting the pipe blank N1, the pipe blank N2 and the pipe blank N3 at the same position in the axial direction respectively, and measuring the opening value of the cut pipe blank N1, the pipe blank N2 and the pipe blank N3 at the cutting position respectively;

[0021] S8, cutting compression samples at the same position on the inner side and the outer side of the hoop section of the pipe blank N1, the pipe blank N2 and the pipe blank N3 respectively, and performing compression test to obtain the compression mechanical property data of the inner side and the outer side of the hoop section of the pipe blank N1, the pipe blank N2 and the pipe blank N3.

[0022] Preferably, the initial parameters of the pipeline pipe to be corrected include the total length L of the pipeline pipe to be corrected, the initial circumference L0 of the pipeline pipe to be corrected, the initial bending deflection I of the pipeline pipe to be corrected, the wall thickness t of the pipeline pipe to be corrected, the initial ellipticity β of the hoop section of the pipeline pipe to be corrected and the diameter reduction rate δ of the pipeline pipe to be corrected.

[0023] Preferably, in step S1, the diameter reduction rate δ of the pipeline pipe to be corrected is 0.3%-2%.

[0024] Preferably, in step S2, the single correction length L' of the pipeline pipe to be corrected is greater than 0.5m.

[0025] Preferably, the diameter reduction die includes an upper diameter reduction die, a right diameter reduction die, a left diameter reduction die and a lower diameter reduction die, and the central angles of the upper diameter reduction die, the right diameter reduction die, the left diameter reduction die and the lower diameter reduction die are all 90° and have the same curvature radius.

[0026] Preferably, during the process that the upper diameter reduction die and the lower diameter reduction die simultaneously compress the pipeline pipe to be corrected, the moving distance of the upper diameter reduction die and the lower diameter reduction die in the vertical direction is equal to the moving distance of the left diameter reduction die and the right diameter reduction die in the horizontal direction.

[0027] In another aspect of the present application, a progressive correction and reinforcement device for submarine pipeline pipes is provided, which comprises a press, an upper reducing die, a right reducing die, a right sliding block, a lower reducing die, a pin, a spring, a limit block, a left reducing die, a left sliding block and a U-shaped frame, the moving end of the press and the mounting end of the upper reducing die are fixedly connected, the mounting end of the right reducing die is connected with the first mounting end of the U-shaped frame through the right sliding block, the mounting end of the left reducing die is connected with the second mounting end of the U-shaped frame through the left sliding block, the mounting end of the lower reducing die is connected with the first end of the pin, the second end of the pin is connected with the first end of the limit block through the spring, the spring is located between the lower reducing die and the limit block, and the second end of the limit block is connected with the third mounting end of the U-shaped frame.

[0028] Preferably, the U-shaped frame is symmetric about the center, and the inner wall of the U-shaped frame has an inclination angle α of arctan 2°.

[0029] Compared with the prior art, the present application has the following advantages:

[0030] 1. The present application applies displacement load to the press to control the synchronous compression of the upper reducing die, the right reducing die, the left reducing die and the lower reducing die on the pipeline pipe to be corrected, thereby realizing the synchronous reducing correction of the pipeline pipe to be corrected in four different directions, and the progressive reducing correction device has compact structure, is easy to install, has low cost and is easy to popularize, and can be applied to various types of ordinary presses.

[0031] 2. The reducing correction method of the present application has a reducing rate range of 0.3%-2%, and the ovality of the pipeline pipe after reducing correction is less than 1% and the straightness is less than 2‰, thereby improving the dimensional accuracy of the pipeline pipe, the residual stress distribution is uniform and the peak value is less than 50MPa, the outer circumferential compression yield strength is improved by 27%, and the hydrostatic buckling compression load in deep sea environment is improved by 30%, and the method is more suitable for geometric correction and calibration and compression buckling performance reinforcement of deep sea service pipeline pipes.

[0032] 3. The present application can be applied to the geometric shape calibration of oil and gas pipeline pipes of various outer diameters by replacing different reducing dies. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 The process flow chart of the progressive correction and reinforcement method for submarine pipeline pipes of the present application;

[0034] Figure 2 The loading of the reducing die in the progressive correction and reinforcement device for submarine pipeline pipes of the present application and the force diagram of the reducing pipeline pipe;

[0035] Figure 3aSchematic diagram of the progressive straightening and reinforcing device for submarine pipeline pipes according to the present application in the process of loading the press before the press loading;

[0036] Figure 3b Schematic diagram of the progressive straightening and reinforcing device for submarine pipeline pipes according to the present application in the process of loading the press;

[0037] Figure 3c Schematic diagram of the progressive straightening and reinforcing device for submarine pipeline pipes according to the present application in the process of unloading the press to the initial position;

[0038] Figure 4a Schematic diagram of the first section of the pipeline pipe to be straightened in the progressive straightening and reinforcing method for submarine pipeline pipes according to the present application in the process of reducing the diameter for straightening;

[0039] Figure 4b Schematic diagram of the Nth section of the pipeline pipe to be straightened in the progressive straightening and reinforcing method for submarine pipeline pipes according to the present application in the process of reducing the diameter for straightening;

[0040] Figure 5 Schematic diagram of the U-shaped frame in the progressive straightening and reinforcing device for submarine pipeline pipes according to the present application;

[0041] Figure 6 Assembly relationship diagram of the lower reducing die, spring, pin and limiting block in the progressive straightening and reinforcing device for submarine pipeline pipes according to the present application;

[0042] Figure 7a Schematic diagram of the change of the ellipticity of the circumferential section before and after the reducing straightening of the pipeline pipe to be straightened in the progressive straightening and reinforcing method for submarine pipeline pipes according to the present application;

[0043] Figure 7b Schematic diagram of the ellipticity of the circumferential section in the axial length range of the pipeline pipe with a length of 12 m after the reducing straightening in the progressive straightening and reinforcing method for submarine pipeline pipes according to the present application;

[0044] Figure 7c Schematic diagram of the change of the straightness before and after the reducing straightening of the pipeline pipe with a length of 12 m in the progressive straightening and reinforcing method for submarine pipeline pipes according to the present application;

[0045] Figure 8 Schematic diagram of the cross-sectional opening after cutting the pipe blank N1, pipe blank N2 and pipe blank N3 in the same position along the axis in the progressive straightening and reinforcing method for submarine pipeline pipes according to the present application;

[0046] Figure 9a Graph of the compressive mechanical properties of the pipe blank N1 and pipe blank N2 in the same inner layer and outer layer position in the progressive straightening and reinforcing method for submarine pipeline pipes according to the present application;

[0047] Figure 9bThe compression mechanical property diagram of pipe blank N2 and pipe blank N3 at the same inner layer and outer layer position in the progressive correction and reinforcement method for submarine pipeline pipe of the present application;

[0048] Figure 10 The pipeline pipe volume change and hydrostatic pressure change diagram in the hydrostatic pressure collapse finite element simulation process of the pipeline pipe to be reduced in diameter, the pipeline pipe after diameter reduction correction and the pipeline pipe after diameter reduction correction and low temperature heat treatment in the progressive correction and reinforcement method for submarine pipeline pipe of the present application.

[0049] Main reference signs:

[0050] Press 1, upper reducing die 2, right reducing die 3, right sliding block 4, U-shaped frame 5, pipeline pipe to be corrected 6, lower reducing die 7, spring 8, pin 9, limit block 10, left sliding block 11, left reducing die 12, roller 13. DETAILED DESCRIPTION

[0051] In order to fully understand the technical content, structural features, purposes achieved and effects of the present application, the following will be described in detail in combination with the drawings of the specification.

[0052] The progressive correction and reinforcement method and device for submarine pipeline pipe are suitable for the general press used, wherein the progressive correction and reinforcement method for submarine pipeline pipe, as shown in the figure, has the following specific implementation steps: Figure 1

[0053] S1, according to the initial parameters of the pipeline pipe to be corrected 6, the curvature radius of the reducing die required by the pipeline pipe to be corrected 6 is calculated, and the expression of the curvature radius of the reducing die is as follows:

[0054]

[0055] Wherein, R0 is the curvature radius of the reducing die, δ is the reducing rate of the pipeline pipe to be corrected 6, and L0 is the initial circumference of the pipeline pipe to be corrected 6.

[0056] Specifically, the initial parameters of the pipeline pipe to be corrected 6 include the total length L of the pipeline pipe to be corrected 6, the initial circumference L0 of the pipeline pipe to be corrected 6, the initial bending deflection l of the pipeline pipe to be corrected 6, the wall thickness t of the pipeline pipe to be corrected, the initial out-of-roundness β of the circumferential section of the pipeline pipe to be corrected 6 and the reducing rate δ of the pipeline pipe to be corrected 6. Further, the initial parameters of the pipeline pipe to be corrected 6 also include that the diameter of the pipeline pipe to be corrected 6 ranges from 406mm to 1626mm, the wall thickness of the pipeline pipe to be corrected 6 ranges from 6mm to 35mm, and in a preferred embodiment of the present application, the reducing rate δ of the pipeline pipe to be corrected 6 is 0.3%-2%.

[0057] ​The diameter reduction molds include an upper diameter reduction mold 2, a right diameter reduction mold 3, a left diameter reduction mold 12, and a lower diameter reduction mold 7. The central angles of all four molds are 90° and they have the same radius of curvature. By changing different diameter reduction molds, and thus altering their radii of curvature, diameter reduction calibration of pipeline pipes 6 with various regular outer diameters and thicknesses can be achieved. Compared to the diameter expansion calibration method, the diameter reduction calibration method improves the circumferential compressive yield strength of the pipeline pipe 6, thereby enhancing its resistance to crushing, making it particularly suitable for calibration of deep-sea oil and gas pipelines.

[0058] S2, such as Figure 4a As shown, the pipe 6 to be shaped is fed into the diameter reduction and shaping device by the roller 13 at a feed length L', and the diameter reduction and shaping are performed. The specific operation process is as follows:

[0059] Specifically, the single-cycle calibration length L' of the pipeline 6 to be calibrated is greater than 0.5m.

[0060] S21, such as Figure 3a As shown, start the press 1 and move it vertically towards the pipeline 6 to be calibrated, as shown. Figure 2 As shown, under the action of the press 1, the upper diameter reduction mold 2, the right diameter reduction mold 3, the left diameter reduction mold 12 and the lower diameter reduction mold 7 are loaded synchronously. That is, the upper diameter reduction mold 2 moves vertically, the right diameter reduction mold 3 and the left diameter reduction mold 12 move horizontally along the slide rail in the U-shaped frame 5 respectively. The vertical movement distance of the upper diameter reduction mold 2 and the lower diameter reduction mold 7 is equal to the horizontal movement distance of the left diameter reduction mold 12 and the right diameter reduction mold 3. The upper diameter reduction mold 2, the lower diameter reduction mold 7, the right diameter reduction mold 3 and the left diameter reduction mold 12 reduce the diameter of the pipeline 6 to be corrected in four directions. After the diameter reduction correction, the residual stress distribution of the pipeline is more uniform.

[0061] like Figure 3b As shown, when the loading displacement of press 1 is H, the centers of the upper reducing die 2, lower reducing die 7, right reducing die 3, and left reducing die 12 coincide. At this time, press 1 is closed. The expression for the loading displacement of press 1 is as follows:

[0062]

[0063] Where a is the major axis length of the pipeline 6 to be shaped, b is the minor axis length of the pipeline 6 to be shaped, L0 is the initial circumference of the pipeline 6 to be shaped, and R0 is the radius of curvature of the diameter reduction mold.

[0064] S22. Start the compressor 1 and move it away from the pipeline 6 to be calibrated back to its initial position. Figure 3cAs shown, at this time, the spring 8 rebounds, and the length of the line pipe 6L' to be calibrated is completed to be calibrated in the reduced diameter.

[0065] S3、as Figure 4b As shown, repeat step S2 until the full length of the line pipe 6 to be calibrated is completed to be calibrated in the reduced diameter.

[0066] S4, taking the center of the inner arch of the two end faces of the line pipe calibrated in the reduced diameter as the reference line, measuring the distance between the inner arch line of the line pipe calibrated in the reduced diameter and the reference line, and calculating the straightness of the line pipe calibrated in the reduced diameter, the expression of the straightness is as follows:

[0067]

[0068] Wherein, l max is the farthest distance between the inner arch line and the reference line, and L is the length of the line pipe to be calibrated.

[0069] S5, using a three-coordinate measuring instrument to measure the ovality of the line pipe calibrated in the reduced diameter at the circumferential section, measuring every 2m, and obtaining the ovality of the line pipe calibrated in the reduced diameter at different positions.

[0070] S6, cutting the pipe blank N1 on the line pipe 6 to be calibrated, cutting the pipe blank N2 and the pipe blank N3 on the line pipe calibrated in the reduced diameter, and heat treating the pipe blank N3.

[0071] Further, the lengths of the pipe blank N1, the pipe blank N2 and the pipe blank N3 are equal, all being 500mm, the heat treatment temperature is 300℃, and the heat treatment time is 10min.

[0072] S7, cutting the pipe blank N1, the pipe blank N2 and the pipe blank N3 at the same position in the axial direction respectively, and measuring the opening value of the pipe blank N1, the pipe blank N2 and the pipe blank N3 at the cutting position respectively.

[0073] S8, cutting the compression test sample with the size of at the same position of the inner side and the outer side of the circumferential section of the pipe blank N1, the pipe blank N2 and the pipe blank N3 respectively, and carrying out compression test on the universal testing machine, obtaining the compression mechanical property data of the inner side and the outer side of the circumferential section of the pipe blank N1, the pipe blank N2 and the pipe blank N3, and analyzing the change of the hydrostatic pressure of the line pipe to be calibrated, the line pipe calibrated in the reduced diameter and the line pipe calibrated in the reduced diameter and subjected to low-temperature heat treatment through finite element simulation.

[0074] The progressive calibration and strengthening device for the submarine line pipe, as shown in Figure 3a , 3bAs shown in FIGS. 3a, 3b and 3c, the device comprises a press 1, an upper reducing die 2, a right reducing die 3, a right slider 4, a lower reducing die 7, a pin 9, a spring 8, a limit block 10, a left reducing die 12, a left slider 11 and a U-shaped frame 5. The press 1 is loaded in the vertical direction to achieve the synchronous reducing of the pipe 6 in four directions.

[0075] The fixed end of the press 1 is installed on the working platform of the press. The moving end of the press 1 is fixedly connected with the installation end of the upper reducing die 2. The installation end of the right reducing die 3 is connected with the first installation end of the U-shaped frame 5 through the right slider 4. The fixed end of the right slider 4 is fixedly connected with the installation end of the right reducing die 3 through bolts. The sliding end of the right slider 4 can slide along the trapezoidal groove in the inner surface of the first installation end of the U-shaped frame 5. The installation end of the left reducing die 12 is connected with the second installation end of the U-shaped frame 5 through the left slider 11. The fixed end of the left slider 11 is fixedly connected with the installation end of the left reducing die 12 through bolts. The sliding end of the left slider 11 can slide along the trapezoidal groove in the inner surface of the second installation end of the U-shaped frame 5. As shown in FIG. 3c, the installation end of the lower reducing die 7 is connected with the first end of the pin 9 through threads. The second end of the pin 9 passes through the pin hole of the spring 8 and the limit block 10. The spring 8 is located between the lower reducing die 7 and the limit block 10. The lower end of the spring 8 is installed in the installation hole of the limit block 10. The upper end of the spring 8 is in contact with the installation end of the lower reducing die 7. The second end of the limit block 10 is connected with the third installation end of the U-shaped frame 5. All the degrees of freedom of the limit block 10 are constrained. Figure 6

[0076] Specifically, as shown in FIG. 3d, the U-shaped frame 5 is symmetric about the center. The inner wall angle a of the U-shaped frame 5 is arctan 2°. Figure 5

[0077] After the pipe 6 is subjected to the shape correction and strengthening method of the present application, the ellipticity and straightness of the pipe 6 are improved, the residual stress is reduced and uniformly distributed, the hoop compression yield strength is improved, and the compression crushing resistance is enhanced. The present application is particularly suitable for the shape correction method of the subsea pipeline pipe and the small-diameter-thickness-ratio pipeline pipe.

[0078] The progressive shape correction and strengthening method of the subsea pipeline pipe and the device thereof of the present application are further described below in combination with embodiments:

[0079] In the present embodiment, in the initial parameters of the pipe 6 to be corrected, the total length of the pipe 6 to be corrected is 12 m, the initial circumference L0 of the pipe 6 to be corrected is 1275 mm, the initial bending deflection l of the pipe 6 to be corrected is 30 mm, the wall thickness t of the pipe 6 to be corrected is 32 mm, the initial ellipticity of the hoop section of the pipe 6 to be corrected is 5%, and the reducing rate δ of the pipe 6 to be corrected is 1%.

[0080] ​​S1, according to the initial circumference L0 of the pipeline to be calibrated 6 and the reduction rate δ, the curvature radius of the reduction die required by the pipeline to be calibrated 6 is calculated as 200.9mm.

[0081] S2, as shown in Figure 4a , the pipeline to be calibrated 6 is conveyed into the reduction calibration device by the roller 13 with a feeding length of 1m, and the pipeline to be calibrated 6 is calibrated with a reduction rate δ of 1%, and the specific operation process is as follows:

[0082] S21, as shown in Figure 3a , the press 1 is started to move in the vertical direction close to the pipeline to be calibrated 6, and when the press 1 contacts the upper reduction die 2, the right reduction die 3 and the left reduction die 12 at the same time, the upper reduction die 2 and the lower reduction die 7 move in the vertical direction under the action of the press 1, and the right reduction die 3 and the left reduction die 12 move in the horizontal direction along the slide rail in the U-shaped frame 5.

[0083] As shown in Figure 3b , when the loading displacement H of the press 1 is 10mm, the centers of the upper reduction die 2, the lower reduction die 7, the right reduction die 3 and the left reduction die 12 coincide, and at this time the press 1 is closed.

[0084] S22, the press 1 is started to move away from the pipeline to be calibrated 6 to the initial position, at this time the roller 13, the upper reduction die 2, the right reduction die 3, the lower reduction die 7 and the left reduction die 12 all return to the initial position, as shown in Figure 3c , at this time the spring 8 rebounds, and the reduction calibration of the L' length of the pipeline to be calibrated 6 is completed.

[0085] S3, as shown in Figure 4b , repeat step S2 until the reduction calibration of the full length of the pipeline to be calibrated 6 is completed.

[0086] S4, as shown in Figure 7c , under the process of reduction rate δ of 1%, taking the inner arch center of the two end faces of the pipeline after reduction calibration as the reference line, the maximum distance between the inner arch line of the pipeline after reduction calibration and the reference line is measured to obtain the straightness of the pipeline after reduction calibration, which is 1.5‰, less than the standard pipeline straightness of 2‰, and the pipeline after reduction calibration is qualified.

[0087] S5, as shown in Figure 7a and Figure 7b , under the process of reduction rate δ of 1%, the three coordinate instrument is used to measure the ellipticity of the pipeline after reduction calibration every 2m in the circumferential section to obtain the ellipticity of the pipeline after reduction calibration at different positions, and the ellipticity at different positions is between 0.1% and 0.3%, less than the standard pipeline ellipticity of 1%, and the pipeline after reduction calibration is qualified.

[0088] Further, in the specific embodiment, the same pipeline to be shaped 6 is subjected to the diameter reduction calibration with the diameter reduction rate δ of 1.2% and 1.5% respectively, and the ovality of the pipeline after the diameter reduction shaping is between 0.1% and 0.3% respectively, both less than the standard pipeline ovality of 1%, the straightness of the pipeline after the diameter reduction shaping is 1.2‰ and 1‰ respectively, both less than 2‰, and the pipeline after the diameter reduction shaping with the diameter reduction rate δ of 1.2% and 1.5% is qualified.

[0089] S6, cutting a pipe blank N1 of a certain length on the pipeline to be shaped 6, cutting a pipe blank N2 and a pipe blank N3 on the pipeline after the diameter reduction shaping with the diameter reduction rate δ of 1% respectively, and performing heat treatment on the pipe blank N3.

[0090] Further, in the specific embodiment, the lengths of the pipe blank N1, the pipe blank N2 and the pipe blank N3 are equal, all being 500mm, the temperature of the heat treatment is 300℃, and the duration of the heat treatment is 10min.

[0091] S7, cutting the pipe blank N1, the pipe blank N2 and the pipe blank N3 at the same axial position respectively, and measuring the opening values of the cutting surfaces of the pipe blank N1, the pipe blank N2 and the pipe blank N3 respectively after the cutting, as shown in Figure 8 The opening values of the cutting surfaces of the pipe blank N2 and the pipe blank N3 are far less than that of the pipe blank N1, proving that the hoop residual stress of the pipeline after the diameter reduction shaping and the pipeline after the diameter reduction shaping and heat treatment is less than that of the pipeline to be shaped.

[0092] S8, cutting compression samples with the size of on the inner side and the outer side of the hoop section of the pipe blank N1, the pipe blank N2 and the pipe blank N3 at the same position respectively, and performing unidirectional compression mechanical property experiment on the universal testing machine to obtain the compression mechanical property data of the inner side and the outer side of the hoop section of the pipe blank N1, the pipe blank N2 and the pipe blank N3, as shown in Figure 9a and Figure 9b The hoop compression yield strength of the inner side and the outer side of the pipe blank N1, the pipe blank N2 and the pipe blank N3 is gradually improved, proving that the hoop compression yield strength of the pipeline to be shaped is less than that of the pipeline after the diameter reduction shaping, and the hoop compression yield strength of the pipeline after the diameter reduction shaping is less than that of the pipeline after the diameter reduction shaping and heat treatment; the pipeline to be shaped, the pipeline after the diameter reduction shaping and the pipeline after the diameter reduction shaping and heat treatment are subjected to hydrostatic collapse finite element simulation, as shown in Figure 10 The maximum hydrostatic collapse load of the pipeline to be shaped, the pipeline after the diameter reduction shaping and the pipeline after the diameter reduction shaping and heat treatment is 30MPa, 45MPa and 50MPa respectively, proving the feasibility of the shape shaping and performance strengthening method for the submarine pipeline according to the present application.

[0093] The above-described embodiments are merely intended to describe the preferred embodiments of the present application, and are not intended to limit the scope of the present application. Various changes and modifications made by those skilled in the art to the present application without departing from the spirit of the present application should fall within the scope of the present application defined by the claims.

Claims

1. A progressive shaping and strengthening method for submarine pipeline pipes, characterized in that, The method is implemented using a progressive shaping and strengthening device for submarine pipeline pipes. The device includes a diameter reduction mold, a press, a right slider, a pin, a spring, a limiting block, a left slider, and a U-shaped frame. The diameter reduction mold includes an upper diameter reduction mold, a right diameter reduction mold, a left diameter reduction mold, and a lower diameter reduction mold. The moving end of the press is fixedly connected to the mounting end of the upper diameter reduction mold. The mounting end of the right diameter reduction mold is connected to the first mounting end of the U-shaped frame via the right slider. The mounting end of the left diameter reduction mold is connected to the second mounting end of the U-shaped frame via the left slider. The mounting end of the lower diameter reduction mold is connected to the first end of the pin. The second end of the pin passes through the spring and is connected to the first end of the limiting block. The spring is located between the lower diameter reduction mold and the limiting block. The second end of the limiting block is connected to the third mounting end of the U-shaped frame. The specific implementation steps are as follows: S1. Based on the initial parameters of the pipeline to be shaped, calculate the radius of curvature of the diameter reduction mold required for the pipeline to be shaped. The expression for the radius of curvature of the diameter reduction mold is as follows: ； in, Let the radius of curvature of the diameter reduction die be denoted as . The diameter reduction ratio of the pipeline to be calibrated. The initial perimeter of the pipeline to be calibrated; S2. Determine the single-stage straightening length of the pipeline to be straightened. The rollers are used to feed the pipeline to be shaped to a specified length. The material is fed into a diameter reduction and straightening device for diameter reduction and straightening. The specific operation process is as follows: S21. Start the press and move it vertically towards the pipeline to be shaped. Under the action of the press, the upper and lower reducing dies compress the pipeline to be shaped vertically, while the right and left reducing dies move along the slide rails within the U-shaped frame, compressing the pipeline to be shaped horizontally. When the press's loading displacement is H, the centers of the upper, lower, right, and left reducing dies coincide. At this point, turn off the press. The expression is as follows: ； in, The length of the major axis of the pipeline to be calibrated. The length of the minor axis of the pipeline to be calibrated. Let be the initial perimeter of the pipeline to be calibrated. Let be the radius of curvature of the diameter-reducing die; S22. Start the press and move it away from the pipeline to be shaped back to its initial position. At this point, the spring returns, completing the process of shaped the pipeline. Length reduction and correction; S3. Repeat step S2 until the diameter reduction correction of the entire length of the pipeline to be corrected is completed. S4. Using the inner arch centers of the two end faces of the reduced-diameter pipeline as reference lines, measure the distance between the inner arch line of the reduced-diameter pipeline and the reference line, and calculate the straightness of the reduced-diameter pipeline. The expression is as follows: ； in, This represents the farthest distance between the inner arch line and the baseline. The total length of the pipeline to be calibrated; S5. Use a coordinate measuring machine to measure the ellipticity of the pipeline in the circumferential section after the diameter reduction and straightening. Measure once at certain intervals to obtain the ellipticity of the pipeline at different positions after the diameter reduction and straightening. S6. Cut a tube blank of a certain length from the pipeline to be shaped. Two equal-length pipe blanks are cut from the reduced-diameter pipe after the pipe is shaped. and tube blank and the tube blank Heat treatment is required; S7. At the same axial position, respectively, the tube blanks are... tube blank and tube blank Cut the tube blank and measure the cut tube blanks separately. tube blank and tube blank The opening value at the cut; S8, in the tube blank tube blank and tube blank Compression specimens were cut at the same positions on the inner and outer sides of the circumferential section, and compression tests were performed to obtain the tube blank. tube blank and tube blank The compressive mechanical properties data of the inner and outer sides of the circumferential cross section.

2. The progressive shaping and strengthening method for submarine pipeline pipes according to claim 1, characterized in that, The initial parameters of the pipeline to be calibrated include the total length of the pipeline to be calibrated. Initial perimeter of the pipeline to be calibrated and the diameter reduction rate of the pipeline to be calibrated .

3. The progressive shaping and strengthening method for submarine pipeline pipes according to claim 1 or 2, characterized in that, In step S1, the diameter reduction rate of the pipeline to be shaped is... It ranges from 0.3% to 2%.

4. The progressive shaping and strengthening method for submarine pipeline pipes according to claim 1 or 2, characterized in that, In step S2, the single-cycle straightening length of the pipeline to be straightened is... Greater than 0.5m.

5. The progressive shaping and strengthening method for submarine pipeline pipes according to claim 1, characterized in that, The central angles of the upper diameter reduction mold, the right diameter reduction mold, the left diameter reduction mold, and the lower diameter reduction mold are all 90° and have the same radius of curvature.

6. The progressive shaping and strengthening method for submarine pipeline pipes according to claim 1, characterized in that, During the simultaneous compression of the pipeline to be shaped by the upper diameter reduction mold, the lower diameter reduction mold, the left diameter reduction mold, and the right diameter reduction mold, the vertical movement distance of the upper diameter reduction mold and the lower diameter reduction mold is equal to the horizontal movement distance of the left diameter reduction mold and the right diameter reduction mold.

7. The progressive shaping and strengthening method for submarine pipeline pipes according to claim 1, characterized in that, The U-shaped frame is symmetrical about the center, and the inclination angle of the inner wall of the U-shaped frame is... for °.

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