A spiral steel pipe welding system and its welding method

Abstract

This invention discloses a spiral steel pipe welding system and welding method. The welding system includes a bending device, a shaping device, an inner welding device, and an outer welding device arranged sequentially. The shaping device includes an inner pipe expanding device and an outer pipe pressing device. The inner pipe expanding device includes an outer expanding wheel, a guide rod connected to the outer expanding wheel, a guide sleeve sleeved on the guide rod, and a push rod assembly disposed at the end of the guide rod away from the outer expanding wheel. The wheel surface of the outer expanding wheel abuts against the inner wall of the steel pipe. The guide rod is arranged radially along the steel pipe, and the guide sleeve is arranged radially along the steel pipe. The push rod assembly includes a rotating shaft and a cam fixed to the rotating shaft. The rotating shaft is coaxial with the steel pipe, and the end of the guide rod away from the outer expanding wheel abuts against the wheel surface of the cam. The spiral steel pipe welding system and welding method of this invention solve the problem of uneven seams that occur during the forming of spiral steel pipes in the prior art, ensuring the welding quality of spiral steel pipes.

Description

Technical Field

[0001] This invention belongs to the field of welding, and more specifically relates to a spiral steel pipe welding system and welding method thereof. Background Technology

[0002] Spiral welded steel pipes are widely used in the transportation of natural gas, urban water, heating networks, and water supply and drainage, and generally have large diameters. Spiral welded steel pipes are made from steel strips, which are spirally coiled to form a spiral pipe structure. The seams formed between adjacent steel strips are welded together to form the spiral pipe. Larger diameter pipes can be formed from relatively narrow steel strips. However, during the welding process, the spiral welded steel pipe has significant resilience, making it difficult to align the weld seams or resulting in uneven seams, leading to poor weld quality and low weld strength. Summary of the Invention

[0003] The purpose of this invention is to provide a spiral steel pipe welding system and welding method, which solves the problem of uneven joints that occur during the forming of spiral steel pipes in the prior art, and ensures the welding quality of spiral steel pipes.

[0004] This invention provides a spiral steel pipe welding system, comprising a bending device, a shaping device, an inner welding device, and an outer welding device arranged sequentially. The shaping device includes an inner pipe expanding device and an outer pipe pressing device. The inner pipe expanding device includes an outer expanding wheel, a guide rod connected to the outer expanding wheel, a guide sleeve sleeved on the guide rod, and a push rod assembly disposed on the end of the guide rod away from the outer expanding wheel. The wheel surface of the outer expanding wheel abuts against the inner wall of the steel pipe. The guide rod is arranged radially along the steel pipe, and the guide sleeve is arranged radially along the steel pipe. The push rod assembly includes a rotating shaft and a cam fixed to the rotating shaft. The rotating shaft is coaxial with the steel pipe, and the end of the guide rod away from the outer expanding wheel abuts against the wheel surface of the cam.

[0005] Preferably, a plurality of cams are fitted on the rotating shaft, and a guide rod is connected to each cam. The guide rods are arranged along the inner seam of the spiral steel pipe.

[0006] Preferably, the guide rod is provided with two outward expansion wheels, which are respectively placed on both sides of the inner joint of the spiral steel pipe.

[0007] Preferably, the rotating shaft is fitted with a number of guide wheels that are adapted to the number of cams, with one guide wheel provided on the side of each cam. The guide sleeve is fixed to the guide wheel, and the guide wheel is provided with a shaft hole. The rotating shaft passes through the shaft hole and its diameter is smaller than the diameter of the shaft hole.

[0008] Preferably, the guide wheel is detachably connected to an installation assembly, which includes an installation shaft and several connecting parts. The connecting parts include two clamps detachably connected to the outer wheel surface of the guide wheel. A pipe clamp is provided on one clamp and is fixedly connected to the installation shaft. The diameter of the guide wheel is smaller than the diameter of the spiral steel pipe, and the distance from the pipe clamp to the shaft is smaller than the radius of the spiral steel pipe.

[0009] Preferably, the cam is connected to a shaft clamp, and the cam is fixedly connected to the rotating shaft through the shaft clamp. The shaft clamp includes a fixed part and a movable part separate from the fixed part. The fixed part is fixedly connected to the cam, and the movable part is detachably connected to the fixed part.

[0010] Preferably, the guide rod is provided with a centerline scale, and the cam is provided with a radius indicator scale at the wheel edge position.

[0011] Preferably, the external pressure pipe device includes a plurality of pressure rollers evenly distributed on the outer surface of the spiral steel pipe. The pressure rollers include shaping pressure rollers and pipe-holding pressure rollers. The shaping pressure rollers are arranged along the outer seams of the spiral steel pipe, and the pipe-holding pressure rollers are arranged along the pipe surface between the two outer seams. The outer expansion rollers and shaping pressure rollers are arranged in front of the inner welding device, and the pipe-holding pressure rollers are arranged on the spiral steel pipe between the bending device and the outer welding device.

[0012] Preferably, the welding system further includes an uncoiling device, a first straightening device, a cutting device, a first flaw detection device, a steel strip welding device, a second straightening device, an edge trimming device, an edge milling device, a slag removal device, and a strip feeding device. The bending device is located at the rear of the strip feeding device, and a second flaw detection device is also located at the rear of the outer welding device.

[0013] A spiral steel pipe welding method, using the aforementioned spiral steel pipe welding system, is characterized by the following steps: First, the pipe-holding pressure roller of the external pressure pipe device is installed in place; then, the bending device forms the spiral steel pipe, with the forming length being the length between the bending device and the internal welding device; forming is paused, and the internal expansion device and the external pressure pipe device are installed in place, ensuring that the external expansion roller is arranged along the inner seam of the spiral steel pipe and that the forming pressure roller is arranged along the outer seam of the spiral steel pipe, with the pipe-holding pressure roller positioned on the spiral steel pipe between the bending device and the external welding device; then, the welding system is started, the bending device continues to form the spiral steel pipe, and the internal welding device is started simultaneously; when the spiral steel pipe reaches the position of the external welding device, the external welding device is started.

[0014] The beneficial effects of the spiral steel pipe welding system of the present invention are as follows: By setting an internal expansion device and an external pressure device, the spiral steel pipe after bending is shaped after bending. Specifically, the spiral steel pipe is squeezed and limited at the inner and outer joint positions of the newly bent (not yet welded) spiral steel pipe to ensure good connection between the inner and outer joints. Then, the joints are welded by the inner and outer welding devices, resulting in good weld quality.

[0015] The beneficial effect of the spiral steel pipe welding method of the present invention is that: first, the inner and outer joints of the spiral steel pipe that has just been bent and formed (but not yet welded) are positioned to ensure good joint connection, and then welding is performed to improve the welding quality. Attached Figure Description

[0016] Figure 1 This is a schematic diagram showing the arrangement of a shaping device inside a spiral steel pipe in a spiral steel pipe welding system according to the technical solution of the present invention.

[0017] Figure 2 This is a schematic diagram of the internal expansion tube device in the technical solution of the present invention.

[0018] Figure 3 This is a front view of the shaping device in the technical solution of the present invention after it is installed on the spiral steel pipe.

[0019] Figure 4 This is a schematic diagram of the connection between the cam and the rotating shaft in the invention. Detailed Implementation

[0020] To facilitate understanding of the technical solution of the present invention by those skilled in the art, the technical solution of the present invention will now be further described in conjunction with specific embodiments and accompanying drawings.

[0021] This invention provides a spiral steel pipe welding system, comprising a bending device, a shaping device, an inner welding device, and an outer welding device arranged sequentially. The shaping device includes an inner pipe expanding device and an outer pipe pressing device. The inner pipe expanding device includes an outer expanding wheel 13, a guide rod 14 connected to the outer expanding wheel 13, a guide sleeve 15 sleeved on the guide rod 14, and a push rod assembly disposed at the end of the guide rod 14 away from the outer expanding wheel 13. The wheel surface of the outer expanding wheel 13 abuts against the inner wall of the steel pipe. The guide rod 14 is arranged radially along the steel pipe, the guide sleeve 15 is arranged radially along the steel pipe, and the push rod assembly includes a rotating shaft 11 and a cam 12 fixedly connected to the rotating shaft 11. The rotating shaft 11 is coaxially arranged with the steel pipe. The end of the guide rod 14 away from the outer expanding wheel 13 abuts against the wheel surface of the cam 12.

[0022] Based on the above technical solution, by rotating the shaft, the cam is driven to rotate, and the cam wheel surface pushes the guide rod to move outward, so that the outer expansion wheel abuts against the inner wall of the newly formed but not yet welded spiral steel pipe, thereby achieving the inner limit of the steel pipe.

[0023] In this technical solution, a plurality of cams 12 are fitted on the rotating shaft 11, and a guide rod 14 is connected to each cam 12. The guide rods 14 are arranged along the inner seam of the spiral steel pipe. The plurality of guide rods arranged in a front-back position along the rotating shaft along the inner seam of the spiral steel pipe means that the outer expansion wheel on the guide rod is arranged along the inner seam, so that the outer expansion wheel shapes the steel pipe from the position of the inner seam. On the one hand, it realizes the inner limit of the steel pipe, and on the other hand, it realizes the limit of the inner seam of the steel pipe, ensuring good alignment of the spiral steel pipe seam.

[0024] In this technical solution, the guide rod 14 is equipped with two outward expanding wheels 13, which are respectively placed on both sides of the inner joint of the spiral steel pipe. The two outward expanding wheels on the same guide rod limit the two sides of the steel pipe forming the same joint, further ensuring the joint is completed and avoiding the problem of uneven steel strips on both sides of the joint.

[0025] In this technical solution, a number of guide wheels 17, corresponding to the number of cams 12, are fitted onto the rotating shaft 11. Each cam 12 has a guide wheel 17 on its side. A guide sleeve 15 is fixed to the guide wheel 17. The guide wheel 17 has a shaft hole, through which the rotating shaft 11 passes, with a diameter smaller than the diameter of the shaft hole. By setting the guide wheels, the guide sleeve 15 can be installed. At the same time, the guide wheels position the cams, reducing the space occupied by the guide wheels and guide sleeves. This facilitates the setting of multiple cams on the rotating shaft and also facilitates the arrangement of multiple outward-expanding wheels along the joint, ensuring the limiting capability of the outward-expanding wheels.

[0026] In this technical solution, a mounting assembly is detachably connected to the guide wheel 17. The mounting assembly includes a mounting shaft 16 and several connecting parts. The connecting parts include two clamping plates 18 detachably connected to the outer wheel surface of the guide wheel 17. A pipe clamp 19 is provided on one clamping plate 18, and the pipe clamp 19 is fixedly connected to the mounting shaft 19. The diameter of the guide wheel 17 is smaller than the diameter of the spiral steel pipe, and the distance from the pipe clamp 19 to the rotating shaft 11 is smaller than the radius of the spiral steel pipe. Through this technical solution, multiple guide wheels can be installed, avoiding interference between the rotating shaft and the cam and the guide wheels during operation. One end of the mounting shaft 16 extends out of the spiral steel pipe and is fixed, realizing the installation of the mounting shaft. At the same time, the installation position of the guide wheel on the mounting shaft 16 can be adjusted by adjusting the pipe clamp.

[0027] In this technical solution, such as Figure 4 A shaft clamp 122 is connected to the cam 12, and the cam 12 is fixedly connected to the rotating shaft 11 via the shaft clamp 122. The shaft clamp 122 includes a fixed part 1221 and a movable part 1222 separate from the fixed part 1221. The fixed part 1221 is fixedly connected to the cam 12, and the movable part 1222 is detachably connected to the fixed part 1221. The shaft clamp 122 enables the cam to be installed on the rotating shaft, and the position of the cam can be adjusted according to the joint position of the spiral steel pipe.

[0028] In this technical solution, the guide rod 14 is provided with a centerline scale 141, and the cam 12 is provided with a radius indicator scale 121 at the wheel edge position. These scales facilitate alignment during cam installation. During installation, first, align the guide rod and the outward-expanding wheel on the guide rod with the joint position requiring limiting. Then, fix the guide wheel 17 on the mounting shaft, thus limiting the direction of the outward-expanding wheel. Next, align the radius indicator scale 121 on the cam, closest to the rotating shaft, with the centerline scale 141 of the guide rod. Finally, fix the cam on the rotating shaft. During operation, rotating the rotating shaft causes the cam to rotate, pushing the guide rod outward, causing the outward-expanding wheel to press against the inner wall of the spiral steel pipe. One end of the rotating shaft extends outward from the spiral steel pipe and is connected to a motor. A brake is connected to the motor to prevent the rotating shaft from rotating in the opposite direction under external force (the reaction force on the outward-expanding wheel), which would affect the limiting of the outward-expanding wheel on the spiral steel pipe.

[0029] In this technical solution, the external pressure pipe device includes several pressure rollers 2 evenly distributed on the outer surface of the spiral steel pipe. Each pressure roller 2 includes a shaping pressure roller 4 and a pipe-holding pressure roller 3. The shaping pressure roller 4 is arranged along the outer seam of the spiral steel pipe, and the pipe-holding pressure roller 3 is arranged along the pipe surface between the two outer seams. The outer expansion roller 13 and the shaping pressure roller 4 are located in front of the inner welding device, and the pipe-holding pressure roller is arranged on the spiral steel pipe between the bending device and the outer welding device. The external shaping pressure roller 4 and the internal outer expansion roller 13 shape and limit the seam of the spiral steel pipe before welding, further ensuring the flatness of the seam and preventing unevenness in the steel strips on both sides of the seam, thus improving the weld quality and the overall quality of the steel pipe.

[0030] In this technical solution, the welding system also includes an uncoiling device, a first straightening device, a cutting device, a first flaw detection device, a steel strip welding device, a second straightening device, an edge trimming device, an edge milling device, a slag removal device, and a strip feeding device. The bending device is located at the rear of the strip feeding device, and a second flaw detection device is also located at the rear of the outer welding device.

[0031] By installing a first flaw detection device, the steel strip is inspected before forming. If the steel strip itself is damaged, it is cut off using a cutting device to prevent welding of the damaged strip. Edge trimming, milling, and slag removal devices are used to treat both edges of the steel strip before welding, ensuring smooth, impurity-free edges and resulting in high-quality welds. Performing internal welding before external welding further improves weld quality.

[0032] A spiral steel pipe welding method, using the aforementioned spiral steel pipe welding system, includes the following steps: First, the outer diameter of the formed spiral steel pipe is adjusted, and the pipe-holding pressure roller of the outer pressure device is installed in place. Then, the bending device forms the spiral steel pipe 100, with a forming length equal to the length between the bending device and the inner welding device. Forming is paused, and the inner expansion device and the outer pressure device are installed in place, ensuring that the outer expansion roller 13 is arranged along the inner seam of the spiral steel pipe, and that the forming pressure roller is arranged along the outer seam of the spiral steel pipe. The pipe-holding pressure roller is positioned on the spiral steel pipe between the bending device and the outer welding device. The welding system is then started; the bending device continues to form the spiral steel pipe, and the inner welding device is started simultaneously. When the formed length of the spiral steel pipe reaches the position of the outer welding device, the outer welding device is started.

[0033] First, a section of spiral steel pipe is formed, the length of which is the distance between the bending device and the inner welding device. This section should be formed before reaching the inner welding device. Then, based on the formed spiral steel pipe, the inner expanding device and the outer pressing device are installed in place, ensuring that the outer expanding wheel 13 is arranged along the inner seam of the spiral steel pipe, and that the forming pressing wheel is arranged along the outer seam of the spiral steel pipe. The clamping pressing wheel is positioned on the spiral steel pipe between the bending device and the outer welding device. The outer expanding wheel 13 should be arranged along the inner seam for a spiral length, and the inner welding device is positioned close to the last outer expanding wheel. The forming pressing wheel is positioned outside the seam of the outer expanding wheel, so that the forming pressing wheel is opposite to the outer expanding wheel, thus limiting the edge of the steel strip forming the seam from both the outside and inside. The outer welding device is positioned at a spiral position behind the inner welding device to avoid mutual interference between the inner and outer welding operations and ensure welding quality.

[0034] The technical solution of the present invention has been described above by way of example in conjunction with the embodiments and accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made by adopting the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A spiral steel pipe welding system, characterized in that, The device includes a bending device, a shaping device, an inner welding device, and an outer welding device arranged sequentially. The shaping device includes an inner tube expanding device and an outer tube pressing device. The inner tube expanding device includes an outer expanding wheel, a guide rod connected to the outer expanding wheel, a guide sleeve sleeved on the guide rod, and a push rod assembly disposed on the end of the guide rod away from the outer expanding wheel. The wheel surface of the outer expanding wheel abuts against the inner wall of the steel pipe. The guide rod and the guide sleeve are arranged radially along the steel pipe. The push rod assembly includes a rotating shaft and a cam fixed to the rotating shaft. The rotating shaft is coaxial with the steel pipe. The end of the guide rod away from the outer expanding wheel abuts against the wheel surface of the cam. Several cams are sleeved on the rotating shaft, and a guide rod is connected to each cam. The guide rods are arranged along the inner seam of the spiral steel pipe. Two outer expanding wheels are disposed on the guide rods, respectively placed on both sides of the inner seam of the spiral steel pipe. A number of guide rods adapted to the number of cams are sleeved on the rotating shaft. The device comprises a cam, each with a guide wheel on its side, a guide sleeve fixedly connected to the guide wheel, a shaft hole on the guide wheel, and a rotating shaft passing through the shaft hole with a diameter smaller than the diameter of the shaft hole. A shaft clamp is connected to the cam, and the cam is fixedly connected to the rotating shaft via the shaft clamp. The shaft clamp includes a fixed part and a movable part separate from the fixed part. The fixed part is fixedly connected to the cam, and the movable part is detachably connected to the fixed part. A centerline scale is provided on the guide rod, and a radius indication scale is provided on the wheel edge of the cam. The external pressure pipe device includes several pressure rollers evenly distributed on the outer surface of the spiral steel pipe. The pressure rollers include shaping pressure rollers and pipe-holding pressure rollers. The shaping pressure rollers are arranged along the outer seams of the spiral steel pipe, and the pipe-holding pressure rollers are arranged along the pipe surface between the two outer seams. The outward expansion rollers and shaping pressure rollers are located in front of the inner welding device, and the pipe-holding pressure rollers are arranged on the spiral steel pipe between the bending device and the outer welding device.

2. The spiral steel pipe welding system according to claim 1, characterized in that, The guide wheel is detachably connected to an installation assembly, which includes an installation shaft and several connectors. Each connector includes two clamps detachably connected to the outer wheel surface of the guide wheel. A pipe clamp is provided on one clamp and is fixedly connected to the installation shaft. The diameter of the guide wheel is smaller than the diameter of the spiral steel pipe, and the distance from the pipe clamp to the shaft is smaller than the radius of the spiral steel pipe.

3. The spiral steel pipe welding system according to claim 1, characterized in that, It also includes an unwinding device, a first straightening device, a cutting device, a first flaw detection device, a steel strip welding device, a second straightening device, an edge trimming device, an edge milling device, a slag removal device, and a strip feeding device. The bending device is located at the rear of the strip feeding device, and a second flaw detection device is also located at the rear of the outer welding device.

4. A method for welding spiral steel pipes, using the spiral steel pipe welding system according to any one of claims 1 to 3, characterized in that, The process includes the following steps: First, install the pipe-holding pressure roller of the external pressure pipe device into place. Then, the bending device forms the spiral steel pipe, with the forming length being the length between the bending device and the inner welding device. The forming process is paused, and the inner expansion device and the external pressure pipe device are installed into place, ensuring that the outer expansion roller is arranged along the inner seam of the spiral steel pipe and that the forming pressure roller is arranged along the outer seam of the spiral steel pipe. The pipe-holding pressure roller is positioned on the spiral steel pipe between the bending device and the outer welding device. The welding system is then started, and the bending device continues to form the spiral steel pipe while the inner welding device is simultaneously activated. When the formed length of the spiral steel pipe reaches the position of the outer welding device, the outer welding device is activated.

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