Long-distance large-diameter pipeline double-sided submerged arc welding method and device

Abstract

This invention, entitled "A Method and Apparatus for Double-Sided Submerged Arc Welding of Long-Distance, Large-Diameter Pipes," belongs to the field of welding technology. The technical problem it aims to solve is the low welding efficiency of long-distance, large-diameter pipes. The key technical points are as follows: the apparatus includes a first roller frame, a second roller frame, a column, and a lifting platform. The first and second roller frames are arranged along the axial direction of the pipe. The lifting platform is mounted on the column, with the first and second roller frames positioned between the columns. A lifting rod is provided on the lifting platform, extending downwards through the platform. First mounting plates are provided on opposite sides of the lifting rod, and a second mounting plate is positioned above the first mounting plate. Distance sensors are provided on both the first and second mounting plates, arranged opposite each other. The stator of an angle encoder is located on the first mounting plate, and the rotor of the angle encoder is mounted on the outer wall of the pipe.

Description

Technical Field

[0001] This invention relates to the field of welding technology, and in particular to a method and apparatus for double-sided submerged arc welding of long-distance, large-diameter pipes. Background Technology

[0002] In some engineering projects, there are situations where pipelines are long and have large diameters, but due to the special circumstances of the pipeline installation, the welding requirements are very high. For example, in one pipeline construction plan, the design involved purchasing steel pipes, welding them on-site, launching them section by section, floating them as a whole, and sinking them in one go. The total length of the submerged pipe was 1171 meters, the diameter was D2800, the wall thickness was 28mm, and the total weight of the submerged pipe was 2330.5t. The circumferential welds of the steel pipes were classified as Class I welds, with a weld quality grade of Grade I. The circumferential welds of the steel pipes were double-sided welds, and the post-weld strength should not be lower than that of the base material. The ultrasonic testing sampling rate for the welds was 100%, and 10% of the welds were subjected to radiographic or TOFD testing. The ultrasonic testing grade was Grade B, and the acceptance grade was Grade I. The radiographic testing or TOFD test grade was Grade B, and the acceptance grade was not lower than Grade II.

[0003] During pipeline production, due to errors and other factors, the inner and outer contours of pipelines are not true circles, but rather ellipses. Pipeline production typically uses ellipticity measurement to define these contours. However, even pipelines meeting ellipticity requirements still have a 0.3% error in their major and minor axes, which is 8.4mm in the example above. The requirement for Class I welds is a misalignment of ≤2mm. During welding, if the major axis of one pipeline is parallel to its minor axis instead of the major axis of another, there is a significant deviation between the two pipelines. This usually requires multi-point measurement methods to determine the major axis of the pipeline, positioning it, and then installing a welding robot to weld it. However, welding robots require repeated manual installation and removal of the robot track and worker operation of the platform for debugging, which is time-consuming and inefficient. Summary of the Invention

[0004] The purpose of this invention is to provide:

[0005] A method and apparatus for double-sided submerged arc welding of long-distance, large-diameter pipelines are disclosed to solve the technical problem of low welding efficiency in long-distance, large-diameter pipelines.

[0006] Terminology Explanation: Unless otherwise defined, all technical terms used herein have the same meanings as commonly understood by one of ordinary skill in the art. Unless otherwise stated, all patents, patent inventions, and publications cited in this document are incorporated herein by reference in their entirety. If multiple definitions exist for terms, the definition provided in this chapter shall prevail.

[0007] It should be understood that the above brief description and the following detailed description are exemplary and for illustrative purposes only, and do not limit the subject matter of the invention in any way. In this invention, the singular is used in conjunction with the plural unless otherwise specifically stated. It should also be noted that, unless otherwise stated, the use of “or” or “or” means “and / or”. Furthermore, the use of the term “comprising” and other forms such as “including,” “containing,” and “contains” are not limiting.

[0008] Unless specifically defined herein, the use of all commercially available products herein employs standard techniques. For example, it may be carried out using the manufacturer's instructions for use with the kit, or in accordance with methods known in the art or the description of this invention. The techniques and methods described herein can generally be implemented according to conventional methods well known in the art, based on the descriptions in the various summary and more specific documents cited and discussed in this specification.

[0009] In a first aspect, the present invention provides: a double-sided submerged arc welding device for long-distance, large-diameter pipes. It includes a first roller frame, a second roller frame, a column, and a lifting platform. The first roller frame and the second roller frame are arranged along the axial direction of the pipeline. The lifting platform is arranged on the column, and the first roller frame and the second roller frame are between the columns. The lifting platform is equipped with a lifting rod that extends downward through the lifting platform. A first mounting plate is provided on each of the opposite sides of the lifting rod. A second mounting plate is provided above the first mounting plate. Distance sensors are provided on both the first and second mounting plates and are arranged opposite to each other. The stator of an angle encoder is provided on the first mounting plate, and the rotor of the angle encoder is on the outer wall of the pipe.

[0010] Furthermore, it also includes a first welding trolley and a second welding trolley, the first welding trolley being on the lifting platform and the second welding trolley being inside the pipeline.

[0011] Furthermore, the first roller frame is provided with a fixed frame, the fixed frame is provided with a stop wheel, and the first roller frame has a drive mechanism for driving the pipe to roll.

[0012] Furthermore, the column has a hollow structure, a sprocket is provided inside the column, and a first drive motor is provided on the side wall of the column and connected to the sprocket via a chain. One end of the chain is connected to the lifting platform.

[0013] Furthermore, the lifting platform is provided with a guide rail, and a movable plate is provided on the guide rail. The lifting rod moves along the guide rail under the drive of the movable plate.

[0014] Furthermore, the movable plate is provided with a lifting cylinder, the piston rod of the lifting cylinder is vertically upward, the piston rod of the lifting cylinder is provided with a lifting plate, and the lifting rod is set on the lifting plate.

[0015] Furthermore, the lifting plate is provided with a second drive motor, and a gear is coaxially provided on the output shaft of the second drive motor. The side wall of the lifting rod is provided with transmission teeth that mesh with the gear. The moving plate is provided with a guide tube, and the lifting rod is inside the guide tube.

[0016] Furthermore, the first mounting plate is located at the bottom end of the lifting rod, the top end of the lifting rod is provided with a fixing plate, the fixing plate is provided with a lead screw, the second mounting plate is threadedly connected to the lead screw, and the fixing plate is provided with a third drive motor for driving the lead screw to rotate.

[0017] Secondly, this invention provides: a method for double-sided submerged arc welding of long-distance, large-diameter pipes. The above-mentioned double-sided submerged arc welding device for long-distance, large-diameter pipelines also includes the following steps: The inner and outer contours of the pipe are identified using distance sensors and angle encoders; Rotate one of the two pipes to make the major axes of the inner contours of the two pipes parallel, and then fix them with MIG welding after installing the alignment tool; Remove the jointing device, set up a second welding trolley inside the pipeline, and weld the inner circumferential seam; Position the first welding trolley on the lifting platform to weld the outer circumferential seam; After welding is completed, the weld is inspected.

[0018] Furthermore, when welding the inner circumferential seam, the angle encoder detects the rotation angle of the pipe, and the welding speed of the second welding carriage is corrected by the speed sensor of the second welding carriage.

[0019] The beneficial effects of this invention are as follows: 1. By using distance sensors and angle encoders to identify the outer and inner contours of the pipes, the major and minor axes of the two pipes can be located before welding, so that the major axes of the two pipes are parallel before welding, thereby improving the pipe positioning efficiency and shortening the overall time of pipe welding.

[0020] 2. The second welding carriage dynamically adjusts the welding speed according to its movement inside the pipeline and the pipeline's rotation speed, so that the welding speed is precisely matched to the circumferential seam inside the pipeline, improving welding accuracy and ensuring that the welding meets the welding requirements. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the welding device.

[0022] Figure 2 It is a schematic diagram showing the internal structure of the pipeline.

[0023] Figure 3 This is a structural diagram of the column and lifting platform.

[0024] Figure 4 This is a schematic diagram showing the internal structure of the lifting platform.

[0025] Explanation of reference numerals in the attached drawings: 1. First roller frame; 2. Second roller frame; 3. Pipe; 4. Reinforcing rib; 5. Fixing frame; 6. Thrust wheel; 7. Column; 8. Lifting platform; 9. Sprocket; 10. Chain; 11. First drive motor; 12. Guide rail; 13. Moving plate; 14. Lifting cylinder; 15. Lifting plate; 16. Lifting rod; 17. First mounting plate; 18. Second mounting plate; 19. Distance sensor; 20. Angle encoder; 21. Transmission gear; 22. Second drive motor; 23. Gear; 24. Fixing plate; 25. Lead screw; 26. Third drive motor; 27. Guide sleeve; 28. First welding carriage; 29. ​​Second welding carriage. Detailed Implementation

[0026] The following non-limiting embodiments are intended to enable those skilled in the art to gain a more comprehensive understanding of the present invention, but do not limit the invention in any way. The following content is merely an exemplary description of the scope of protection claimed by the present invention, and those skilled in the art can make various changes and modifications to the present invention based on the disclosed content, and such changes should also fall within the scope of protection claimed by the present invention.

[0027] The present invention will be further described below by way of specific embodiments. Unless otherwise specified, all instruments, devices, equipment, reagents, products, etc., used in the embodiments of the present invention are obtained through conventional commercial means.

[0028] Reference Figure 1 A double-sided submerged arc welding device for long-distance, large-diameter pipelines includes a first roller frame 1 and a second roller frame 2. Both the first roller frame 1 and the second roller frame 2 are mounted on a pre-laid track on the ground and can move forward and backward along the track. The first roller frame 1 has a drive mechanism that can drive the rollers on the roller frame to roll, so that after the pipeline 3 is placed on the first roller frame 1, it can drive the pipeline 3 to roll. The second roller frame 2 is a common type of roller frame, used to support the other end of the pipeline 3, keeping the pipeline 3 horizontal, and driven by the rotation of the pipeline 3.

[0029] Reference Figure 2The first roller frame 1 is equipped with a fixed frame 5, and a stop wheel 6 is provided inside the fixed frame 5. A reinforcing rib 4 is fixed on the side wall of the pipe 3, and the reinforcing rib 4 is at the edge of the opening of the pipe 3. After the pipe 3 is placed on the first roller frame 1, the side wall of the reinforcing rib 4 abuts against the circumferential surface of the stop wheel 6. When the pipe 3 rotates, the stop wheel 6 rotates accordingly. At the same time, the stop wheel 6 blocks the axial displacement of the pipe 3 during the rotation process, ensuring that the pipe 3 rotates in place and does not rotate spirally.

[0030] Reference Figure 3 The long-distance, large-diameter double-sided submerged arc welding device also includes a column 7 and a lifting platform 8. The lifting platform 8 is on the column 7 and moves up and down on the column 7 via the drive of the column 7. The column 7 has a hollow structure and a sprocket 9 is installed inside the column 7. A first drive motor 11 that drives the sprocket 9 to rotate is fixed on the side wall of the column 7. One end of the chain 10 on the sprocket 9 is fixedly connected to the lifting platform 8, so that the lifting platform 8 can be pulled up and down along the column 7 via the chain 10.

[0031] Reference Figure 1 It is understandable that a moving platform can also be set at the bottom of column 7 so that column 7 can be moved.

[0032] Reference Figure 4 The lifting platform 8 is equipped with a guide rail 12, and a movable plate 13 is mounted on the guide rail 12. The movable plate 13 can move along the guide rail 12. A lifting plate 15 is mounted on the movable plate 13, and a lifting cylinder 14 is provided between the movable plate 13 and the lifting plate 15. The lifting cylinder 14 is fixed to the movable plate 13, and the lifting plate 15 is fixed to the piston rod of the lifting cylinder 14. The extension and retraction of the piston rod of the lifting cylinder 14 can drive the lifting plate 15 to rise and fall. A lifting rod 16 is provided on the lifting plate 15, and the lifting rod 16 passes through the lifting plate 15, the movable plate 13, and the lifting platform 8 and extends thereafter. A second drive motor 22 is provided on the lifting plate 15, and a gear 23 is connected to the output shaft of the second drive motor 22. The side wall of the lifting rod 16 is provided with transmission teeth 21 that can mesh with the gear 23. Driven by the second drive motor 22, the lifting rod 16 can be driven to rise and fall. A guide tube is fixed on the movable plate 13, and the lifting rod 16 is inside the guide tube. The side wall of the lifting rod 16 is in contact with the side wall of the guide tube, so that the guide tube can guide the lifting rod 16 to rise and fall, thereby improving the stability of the lifting rod 16.

[0033] Reference Figure 4The bottom end of the lifting rod 16 is provided with a first mounting plate 17, and a second mounting plate 18 is provided above the first mounting plate 17. Both the first mounting plate 17 and the second mounting plate 18 are equipped with distance sensors 19. For easy distinction, the one on the first mounting plate 17 is distance sensor 19A, and the one on the second mounting plate 18 is distance sensor 19B. Distance sensors 19A and 19B are arranged facing each other, i.e., distance sensor 19A faces distance sensor 19B, and distance sensor 19B faces distance sensor 19A. Distance sensors 19B and 19A are respectively located on the outside and inside of the pipe 3. Distance sensor 19B measures the gap between itself and the outer wall of the pipe 3, and distance sensor 19A measures the gap between itself and the inner wall of the pipe 3, facilitating the subsequent generation of the outer and inner contours around the welding area of ​​the pipe 3 based on changes in the gaps.

[0034] Reference Figure 4 The first mounting plate 17 also has a stator of an angle encoder 20 installed on it. The detection end of the angle encoder 20 is vertically downward. After the rotor is arranged in the pipe 3, it can detect the rolling angle of the pipe 3.

[0035] Reference Figure 4 A fixed plate 24 is fixed to the top of the lifting rod 16. A lead screw 25 is installed on the fixed plate 24. The lead screw 25 passes through the second mounting plate 18 and connects to the first mounting plate 17. The lead screw 25 is threadedly connected to the second mounting plate 18. A third drive motor 26 is installed on the fixed plate 24 to drive the lead screw 25 to rotate. The third drive motor 26 can drive the lead screw 25 to rotate, and the second mounting plate 18 can rise and fall under the drive of the lead screw 25, thereby controlling the sensor B to move closer to or further away from the sensor A, adjusting the distance between the distance sensor 19A and the distance sensor 19B to adapt to pipes 3 with different wall thicknesses. The rising and falling of the lifting rod 16 can drive the distance sensor 19A and the distance sensor 19B to rise and fall as a whole to adapt to pipes 3 with different diameters. The horizontal movement of the moving plate 13 facilitates the adjustment of the detection position of the distance sensor 19A and the distance sensor 19B, further improving adaptability.

[0036] Reference Figure 2 and Figure 4 The long-distance, large-diameter double-sided submerged arc welding device also includes a first welding carriage 28 and a second welding carriage 29. The first welding carriage 28 is mounted on a lifting platform 8, and the welding torch passes through the lifting platform 8 and extends downwards. The second welding carriage 29 is mounted inside the pipe 3. During the rolling of the pipe 3, the second welding carriage 29 travels within the pipe 3, ensuring that the welding position of the welding torch is always at the bottom end of the pipe 3. The second welding carriage 29 integrates a speed sensor, which can automatically control the travel speed of the second welding carriage 29 according to the vehicle speed and a preset program.

[0037] This invention also discloses a method for double-sided submerged arc welding of long-distance, large-diameter pipelines, which uses the aforementioned double-sided submerged arc welding device for long-distance, large-diameter pipelines, and further includes the following steps: S1 identifies the inner and outer contours of pipe 3.

[0038] During the production of pipe 3, due to errors in the manufacturing process, the wall thickness of pipe 3 is not completely uniform, which can lead to welding quality that does not meet requirements. The first mounting plate 17 extends into pipe 3 and maintains a distance from the inner wall of pipe 3, ensuring that the measuring end of sensor A is always at a distance from the inner wall of pipe 3. Similarly, the distance sensor 19B is protected by adjusting the distance between the second mounting plate 18 and the outer wall of pipe 3 using the lead screw 25, ensuring that the distance sensor 19B is always at a distance from the outer wall of pipe 3. This protects distance sensors 19A and 19B from damage caused by direct contact with pipe 3.

[0039] Pipe 3 is transported to the first roller frame 1 and the second roller frame 2, and then transported to the designated workstation by the first roller frame 1 and the second roller frame 2. After the distance sensors 19A and 19B are in place, the drive mechanism of the first roller frame 1 drives the rollers to rotate, thereby causing the pipe 3 to rotate one revolution. During the rotation of the pipe 3, the distance sensors 19A and 19B continuously detect the distance, thereby obtaining the distance between the inner wall and the outer wall of the pipe 3. The angle encoder 20 continuously detects the rotation angle of the pipe 3.

[0040] Establish a coordinate system with the projection point of the idealized pipe 3's rotation axis as the origin, the vertical direction as the y-axis, and the horizontal direction (perpendicular to the rotation axis of pipe 3) as the x-axis. Based on the readings d_i of distance sensors 19A and 19B and the angle θ_i through which pipe 3 rotates, calculate the coordinates of the points corresponding to the readings of distance sensors 19A and 19B in the coordinate system. Use B-spline curves for fitting to reconstruct the inner and outer contours of pipe 3.

[0041] The inner and outer contours of the splicing area of ​​the two pipe segments 3 that need to be spliced ​​are identified. While restoring the inner and outer contours of the pipe segments 3, the correspondence of the major axes of the inner contours of the two pipe segments 3 can be known.

[0042] S2, Pipe 3 is positioned, and pipe 3 is connected and fixed by electric welding using MIG welding.

[0043] One section of pipe 3 is rotated so that the major axes of the inner contours of the two sections of pipe 3 are parallel. Then, the first roller frame 1 moves pipe 3 closer to the other section of pipe 3 for preliminary splicing. By making the inner contours of the two sections of pipe 3 parallel, the processing error caused by splicing the two sections of pipe 3 is minimized as much as possible, which facilitates meeting the requirements of high-precision welding.

[0044] When splicing two pipe sections 3, a jointing device is installed to minimize the errors caused by the pipe sections 3 themselves. When the two pipe sections 3 are fixed by MIG welding, the welding error is even smaller.

[0045] S3, remove the jointing device, and set up a second welding trolley 29 inside pipe 3 to weld the inner circumferential seam.

[0046] After the MIG welding is completed, the butt joint is removed, and a second welding carriage 29 is arranged in the pipe 3 so that the welding gun of the second welding carriage 29 is facing the weld seam, so that subsequent automatic welding can be performed.

[0047] An angle encoder 20 rotor is fixed inside pipe 3. As pipe 3 rotates, the second welding carriage 29 travels along the weld seam inside pipe 3. The angle encoder 20 detects the rotation angle of pipe 3. Based on the speed sensor of the second welding carriage 29 and the angle detected by the angle encoder 20, it is determined whether the stroke of the second welding carriage 29 matches the rotation amplitude of pipe 3. This helps determine if the second welding carriage 29 is slipping, and the welding speed is controlled accordingly to ensure welding quality.

[0048] S4, position the first welding carriage 28, and perform outer circumferential seam welding.

[0049] Adjust the height of the lifting platform 8 so that the top of the pipe 3 enters the welding range of the welding torch of the first welding carriage 28, and adjust the welding torch toward the weld. The pipe 3 rotates to weld the outer circumferential seam. Since the first welding carriage 28 is fixed during welding, the rotation angle of the pipe 3 can be used to identify whether there is slippage during the rotation process, thereby adjusting the welding speed of the first welding carriage 28 to ensure welding quality.

[0050] S5. After welding is completed, the weld is inspected.

[0051] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A double-sided submerged arc welding device for long-distance, large-diameter pipelines, characterized in that: It includes a first roller frame (1), a second roller frame (2), a column (7) and a lifting platform (8). The first roller frame (1) and the second roller frame (2) are arranged along the axial direction of the pipe (3). The lifting platform (8) is arranged on the column (7). The first roller frame (1) and the second roller frame (2) are located between the column (7). The lifting platform (8) is provided with a lifting rod (16), which extends downward through the lifting platform (8). The lifting rod (16) is provided with a first mounting plate (17) on both sides opposite to each other. A second mounting plate (18) is provided above the first mounting plate (17). Both the first mounting plate (17) and the second mounting plate (18) are provided with distance sensors (19), which are arranged opposite to each other. The first mounting plate (17) is provided with the stator of an angle encoder (20), and the rotor of the angle encoder (20) is on the outer wall of the pipe (3).

2. The double-sided submerged arc welding device for long-distance, large-diameter pipelines according to claim 1, characterized in that: It also includes a first welding trolley (28) and a second welding trolley (29), the first welding trolley (28) being on the lifting platform (8) and the second welding trolley (29) being inside the pipe (3).

3. The double-sided submerged arc welding device for long-distance, large-diameter pipelines according to claim 1, characterized in that: The first roller frame (1) is provided with a fixed frame (5), and the fixed frame (5) is provided with a stop wheel (6). The first roller frame (1) has a driving mechanism for driving the pipe (3) to roll.

4. The double-sided submerged arc welding device for long-distance, large-diameter pipelines according to claim 1, characterized in that: The column (7) is a hollow structure. A sprocket (9) is provided inside the column (7). A first drive motor (11) is provided on the side wall of the column (7) and connected to the sprocket (9) via a chain (10). One end of the chain (10) is connected to the lifting platform (8).

5. The double-sided submerged arc welding device for long-distance, large-diameter pipelines according to claim 1, characterized in that: The lifting platform (8) is provided with a guide rail (12), and a movable plate (13) is provided on the guide rail (12). The lifting rod (16) moves along the guide rail (12) under the drive of the movable plate (13).

6. The double-sided submerged arc welding device for long-distance, large-diameter pipelines according to claim 5, characterized in that: The movable plate (13) is provided with a lifting cylinder (14), the piston rod of the lifting cylinder (14) is vertically upward, the piston rod of the lifting cylinder (14) is provided with a lifting plate (15), and the lifting rod (16) is arranged on the lifting plate (15).

7. The double-sided submerged arc welding device for long-distance, large-diameter pipelines according to claim 6, characterized in that: The lifting plate (15) is provided with a second drive motor (22), and a gear (23) is coaxially provided on the output shaft of the second drive motor (22). The side wall of the lifting rod (16) is provided with a transmission tooth (21) that meshes with the gear (23). The moving plate (13) is provided with a guide tube, and the lifting rod (16) is inside the guide tube.

8. The double-sided submerged arc welding device for long-distance, large-diameter pipelines according to claim 1, characterized in that: The first mounting plate (17) is located at the bottom end of the lifting rod (16), and the top end of the lifting rod (16) is provided with a fixing plate (24). The fixing plate (24) is provided with a lead screw (25). The second mounting plate (18) is threadedly connected to the lead screw (25). The fixing plate (24) is provided with a third drive motor (26) that drives the lead screw (25) to rotate.

9. A method for double-sided submerged arc welding of long-distance, large-diameter pipelines, characterized in that: The long-distance, large-diameter double-sided submerged arc welding device according to any one of claims 1-8 further includes the following steps: The inner and outer contours of the pipe (3) are identified by a distance sensor (19) and an angle encoder (20); Rotate one of the two pipes (3) so that the long axes of the inner contours of the two pipes (3) are parallel, and fix them by MIG welding after installing the fitting device; Remove the jointing device and set up a second welding trolley (29) inside the pipe (3) to weld the inner circumferential seam; Position the first welding trolley (28) on the lifting platform (8) and weld the outer circumferential seam; After welding is completed, the weld is inspected.

10. The method for double-sided submerged arc welding of long-distance, large-diameter pipelines according to claim 9, characterized in that: When welding the inner ring seam, the angle encoder (20) detects the rotation angle of the pipe (3) and, in conjunction with the speed sensor of the second welding carriage (29), corrects the welding speed of the second welding carriage (29).

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