Device for cooling weld seam and reducing residual stress of submerged arc welded steel pipe

Abstract

A device for cooling the weld seam of a submerged arc welded steel pipe and reducing residual stress. The present invention includes a welding robot arm, a steel pipe, a cooling assembly, a stress relief assembly, a four-bar linkage, and a cooling water system; the cooling assembly is connected to the four-bar linkage, the cooling assembly is located above the steel pipe, and the frame of the four-bar linkage is fixedly connected to the welding robot arm; the stress relief assembly is connected to the cooling assembly; the cooling water system supplies water to the cooling assembly; driven by the four-bar linkage, the roller of the cooling assembly contacts the heat-affected zone of the weld; the axial movement of the steel pipe drives the roller to rotate, and the rotation of the roller drives the striker of the stress relief assembly to strike the weld toe of the steel pipe. The beneficial effects are that the structural design is reasonable, and the grains are refined by accelerating the cooling of the heat-affected zone; the device effectively reduces the residual stress of the weld by mechanically striking the weld toe, thereby improving the welding quality and mechanical properties of the steel pipe.

Description

Technical Field

[0001] The invention relates to a submerged arc welding steel pipe device, in particular to a submerged arc welding steel pipe weld cooling and residual stress reducing device, belonging to the technical field of petroleum steel pipe processing. Background Art

[0002] In the production process of submerged arc welding steel pipe, a large welding line energy is required. As the welding line energy increases, the heat affected zone increases, the overheating zone is significantly widened, and the grains become coarser, resulting in a decrease in the plasticity and toughness of the welded joint, and a significant decrease in the low-temperature impact toughness of the welded joint. This effect is particularly significant for low-alloy steel. At the same time, the welding process will cause a certain amount of residual stress in the weld. The presence of residual stress will affect the fatigue strength and geometric stability of the steel pipe weld; in severe cases, it will promote the formation of micro cracks, seriously affecting the corrosion resistance of the weld.

[0003] In the existing submerged arc welding process for steel pipes, lower welding parameters are usually used to reduce the welding line energy, thereby reducing the heat affected zone, ensuring fine grains and the plasticity and toughness of the welded joints. For thick-walled submerged arc welding steel pipes, the welding quality can only be guaranteed by reducing the welding speed, which affects the production efficiency. The residual stress formed in the forming process is reduced by mechanical expansion, which has little effect on the welding residual stress generated in the welding process. Summary of the invention

[0004] In order to overcome the above-mentioned deficiencies existing in existing submerged arc welded steel pipes, the present invention provides a device for cooling the weld seam of submerged arc welded steel pipes and reducing residual stress.

[0005] The technical solution adopted by the present invention to solve its technical problems is: a submerged arc welding steel pipe weld cooling and residual stress reduction device, including a welding robot arm, a steel pipe, a cooling assembly, a stress elimination assembly, a four-bar linkage, and a cooling water system.

[0006] The cooling assembly is connected to the four-bar linkage, the cooling assembly is located above the steel pipe, and the frame of the four-bar linkage is fixedly connected to the welding mechanical arm; the stress relief assembly is connected to the cooling assembly; and the cooling water system supplies water to the cooling assembly.

[0007] Driven by the four-bar linkage, the roller of the cooling assembly contacts the heat-affected zone of the weld.

[0008] The axial movement of the steel pipe drives the roller to rotate, and the rotation of the roller drives the striker of the stress relief assembly to strike the weld toe of the steel pipe.

[0009] The rollers are arranged in pairs on both sides of the weld facing each other, the number of the rollers is at least 2 pairs, and they are arranged longitudinally along the weld; the axes of the rollers are perpendicular to the axis of the steel pipe.

[0010] The cooling assembly is connected to the rocker of the four-bar linkage through a connecting plate. The upper end of the guide screw fixedly mounted on the connecting plate passes through the through hole of the rocker and is fixed by a nut. A compression spring I is installed on the guide screw between the connecting plate and the rocker.

[0011] The upper end of the bracket of the cooling assembly is fixedly connected to the connecting plate.

[0012] A water slip ring and a roller are sequentially installed on the side of the bracket. The stator of the water slip ring is fixedly connected to the bracket, and the rotor of the water slip ring is fixedly connected to the roller.

[0013] The stator and the rotor are provided with water flow channels, which are communicated with the cavity of the roller.

[0014] The cooling water system comprises a water cooler, a water inlet pipeline and a water outlet pipeline, and the cooling water system provides circulating cooling water to the rollers of the cooling assembly.

[0015] The circulating cooling water is supplied by the water chiller, and enters the roller cavity through the water inlet pipeline, the stator's water inlet channel, and the rotor's water inlet channel in sequence, and then flows out through the rotor's water outlet channel, the stator's water outlet channel, and the water outlet pipeline in sequence.

[0016] Furthermore, the water inlet channel and the water outlet channel of the stator are connected to the water inlet pipeline and the water outlet pipeline respectively.

[0017] The upper end of the guide column of the stress relief assembly is fixedly installed with a nut after passing through the bracket through hole; a baffle is fixedly installed in the middle of the guide column, and a compression spring II is axially installed on the guide column between the bracket and the baffle, and the guide column moves up and down along the bracket through hole.

[0018] The roller end surface is provided with more than two shifting blocks at intervals along the circumference; when the roller rotates, the shifting blocks shift the baffle to control the guide column to move up and down, and the striker at the lower end of the guide column strikes the weld toe of the steel pipe.

[0019] Further, the cooling assembly is arranged at the rear of the welding gun.

[0020] Furthermore, the four-bar linkage is driven by a cylinder; the rocker is a flat plate; there are two groups of connecting rod frames, which are laterally symmetrically arranged on both sides of the longitudinal axis of the rocker.

[0021] Furthermore, the number of shifting blocks fixedly installed on the end surface of the roller is 4 to 6 and is evenly distributed along the circumference.

[0022] The beneficial effects of the present invention are that the structural design is reasonable, the grains are refined by accelerating the cooling of the heat-affected zone, and the weld residual stress device is effectively reduced by mechanically tapping the weld toe, thereby improving the welding quality and mechanical properties of the steel pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the structure for cooling the weld seam and reducing residual stress of a submerged arc welded steel pipe according to the present invention.

[0024] Figure 2 yes Figure 1 Right side view (including steel pipe).

[0025] Figure 3 It is a schematic diagram of the structure of the cooling assembly in the present invention.

[0026] Figure 4 yes Figure 3 Left side view (cooling assembly and stress relief assembly).

[0027] Figure 5 It is a structural schematic diagram of the four-bar linkage in the present invention.

[0028] Figure 6 yes Figure 5 Right view of .

[0029] In the figure: 1. Cooling assembly, 2. Four-bar linkage, 3. Welding robot arm, 4. Rocker, 5. Guide screw, 6. Water cooler, 7. Heat affected zone, 8. Steel pipe, 9. Water inlet pipeline, 10. Water outlet pipeline, 11. Bracket, 12. Water slip ring, 13. Stress relief assembly, 14. Stator, 15. Rotor, 16. Roller, 17. Shifter, 18. Compression spring II, 19. Cooling water system, 20. Frame, 21. Cylinder, 22. Nut, 23. Compression spring I, 24. Connecting plate, 25. Guide column, 26. Baffle, 27. Strike pin. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with the accompanying drawings and embodiments. However, those skilled in the art should be aware that the present invention is not limited to the specific embodiments listed, and all embodiments should be included in the protection scope of the present invention as long as they conform to the spirit of the present invention.

[0031] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by terms such as “vertical”, “up”, “down”, “left”, “right” and “horizontal” are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0032] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", "connection", and "seal" should be understood in a broad sense. For example, the connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. The seal can be an oil seal, a packing seal, or other sealing forms. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] See attached Figure 1 , 2 The present invention discloses a device for cooling the weld of a submerged arc welded steel pipe and reducing residual stress, comprising a welding robot arm 3, a steel pipe 8, a cooling assembly 1 capable of accelerating heat dissipation in a heat-affected zone 7 of the weld, a stress elimination assembly 13 capable of reducing residual stress at the interface between the weld surface and the steel pipe base material, a four-bar linkage 2 for driving the cooling assembly 1, and a cooling water system 19 for providing circulating cooling water to the cooling assembly 1.

[0034] The cooling assembly 1 is connected to the four-bar linkage 2, the frame 20 of the four-bar linkage 2 is fixedly connected to the welding robot arm 3, and the cooling assembly 1 is located above the steel pipe 8; the stress relief assembly 13 is connected to the cooling assembly 1; the cooling water system 6 supplies water to the cooling assembly 1; the cooling assembly 1 is arranged behind the welding gun.

[0035] Driven by the four-bar linkage 2 , the roller 16 of the cooling assembly 1 is in close contact with the heat-affected zone 7 of the weld.

[0036] During the welding process of the steel pipe 8 , the axial movement of the steel pipe 8 drives the roller 16 to rotate, and the rotation of the roller 16 drives the striker 27 of the stress relief assembly 13 to strike the weld toe of the steel pipe 8 .

[0037] The rollers 16 are arranged in pairs on both sides of the weld facing each other. There are at least two pairs of rollers 16, and they are arranged longitudinally along the weld. Preferably, there are 2 to 4 pairs of rollers 16. The axes of the rollers 16 and the steel pipe 8 are perpendicular to each other.

[0038] See attached Figure 1 , 5 , 6. The cooling assembly 1 is connected to the rocker 4 of the four-bar linkage 2 through the connecting plate 24; preferably, the rocker 4 is a flat plate, and the number of the connecting rod frames is 2 sets, and the 2 sets of connecting rod frames are transversely symmetrically arranged on both sides of the longitudinal axis of the rocker 4. The upper end of the guide screw 5 fixedly mounted on the connecting plate 24 passes through the through hole of the rocker 4 and is fixed by a nut 22, and a compression spring I 23 is installed on the guide screw 5 between the connecting plate 24 and the rocker 4. Preferably, the four-bar linkage 2 is driven by a cylinder 21, and can also be driven by a hydraulic cylinder or electrically.

[0039] The connecting plate 24 is provided with strip holes for installing the cooling assembly 1, and the distance between each pair of rollers 16 can be adjusted according to the width of the weld to ensure close contact between the rollers 16 and the heat-affected zone 7. Each set of cooling assemblies 1 is separately installed on the connecting plate 24, and the nuts 22 and the compression springs I 23 are adjusted to ensure that each pair of rollers 16 can always be in contact with the heat-affected zone during the production process, so that the heat of the heat-affected zone can be transferred out in time, thereby increasing the cooling speed of the heat-affected zone.

[0040] See attached Figure 3 , 4 The cooling assembly 1 includes a bracket 11, a water slip ring 12, and a roller 16. The bracket 11 is composed of a horizontal plate at the upper end and a vertical plate perpendicular thereto. The horizontal plate at the upper end of the bracket 11 is fixedly connected to the connecting plate 24, usually by bolts. The vertical plate on the side of the bracket 11 is sequentially installed with the water slip ring 12 and the roller 16, and the axes of the water slip ring 12 and the roller 16 are arranged horizontally.

[0041] The water slip ring 12 includes a stator 14 and a rotor 15, one end of the stator 14 is fixedly connected to the bracket 11. One end of the rotor 15 is installed in the inner hole of the stator 14, and the other end is fixedly connected to the roller 16. Preferably, the rotor 15 and the roller 16 are fixedly connected by bolts, and a sealing gasket is installed on the contact end surface of the rotor 15 and the roller 16. The inner hole of the roller 16 is a blind hole. After the rotor 15 and the roller 16 are fixedly connected, the cavity in the roller 16 is used for cooling water to flow.

[0042] The stator 14 and the rotor 15 are provided with water flow channels, and are communicated with the cavity of the roller 16 .

[0043] The cooling water system 19 includes a water chiller 6, a water inlet pipeline 9, and a water outlet pipeline 10. The cooling water system 19 provides circulating cooling water to the roller 16 of the cooling assembly 1; the stator 14 is provided with a water inlet channel and a water outlet channel, and the rotor 15 is provided with a water inlet channel and a water outlet channel; the water inlet channel of the stator 14 is connected to the water inlet channel of the rotor 15, and the water outlet channel of the stator 14 is connected to the water outlet channel of the rotor 15.

[0044] Furthermore, the water inlet channel and the water outlet channel of the stator 14 are communicated with the water inlet pipeline 9 and the water outlet pipeline 10 respectively.

[0045] The circulating cooling water is supplied by the water chiller 6, and the cooling water enters the inner cavity of the roller 16 through the water inlet pipeline 9, the water inlet channel of the stator 14, and the water inlet channel of the rotor 15 in sequence, and then flows out through the water outlet channel of the rotor 15, the water outlet channel of the stator 14, and the water outlet pipeline 10 in sequence, thereby ensuring that the cooling water can flow into the inner cavity of the roller 16 uninterruptedly, and the heat of the weld heat affected zone is transferred out through the cooling water to accelerate the cooling speed. The temperature and flow of the cooling water can be adjusted according to welding parameters such as welding current, welding voltage and welding speed to ensure the cooling effect.

[0046] See attached Figure 3 , 4 The stress relief assembly 13 includes a guide column 25, a baffle 26, and a striker 27. The upper end of the guide column 25 passes through the through hole of the bracket 11 of the cooling assembly 1 and is fixedly installed with a nut; the middle of the guide column 25 is fixedly installed with a baffle 26, and a compression spring II 18 is axially installed on the guide column 25 between the bracket 11 and the baffle 26. The guide column 25 moves up and down along the axial direction of the through hole of the bracket 11.

[0047] The roller 16 end surface of the cooling assembly 1 is evenly and spaced along the circumference and is provided with more than two shifting blocks 17, preferably, the number of the shifting blocks 17 is 4 to 6. When the roller 16 rotates, the shifting blocks 17 shift the baffle 26 to control the guide column 25 to move up and down, and when the guide column 25 moves downward, the striker 27 at the lower end of the guide column 25 strikes the weld toe of the steel pipe 8.

[0048] During the welding process, the welding gun remains stationary and the steel pipe 8 moves axially. Under the action of friction, the steel pipe 8 drives the roller 16 to rotate, thereby driving the shift block 17 fixedly connected to the roller 16 to rotate together. The shift block 17 will shift the baffle 26 on the guide column 25 to compress the compression spring II 18. After rotating to a certain position, the shift block 17 separates from the baffle 26, and under the action of the restoring force of the compression spring II 18, it drives the striker 27 at the lower end of the guide column 25 to strike the weld toe of the steel pipe 8, thereby reducing the residual stress of the weld and improving the weld quality and welding performance.

[0049] The device for cooling the weld and reducing the residual stress of a submerged arc welded steel pipe of the present invention can adjust the water supply temperature and flow rate of a water cooler according to welding parameters such as welding current, welding voltage and welding speed to ensure the cooling effect of the heat affected zone; the frequency of the striker striking the weld toe can be controlled according to the number of shifting blocks installed on the end face of the roller to effectively reduce the residual stress of the weld; the equipment is easy to operate, has good technical and economic value and broad application prospects.

[0050] It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the claims of this patent.

Claims

1. A device for cooling the weld seam of a submerged arc welded steel pipe and reducing residual stress, comprising a welding robot arm and a steel pipe, characterized in that: It also includes a cooling assembly, a stress relief assembly, a four-bar linkage, and a cooling water system; The cooling assembly is connected to the four-bar linkage, the cooling assembly is located above the steel pipe, and the frame of the four-bar linkage is fixedly connected to the welding robot arm; the stress relief assembly is connected to the cooling assembly; the cooling water system supplies water to the cooling assembly; Driven by the four-bar linkage, the roller of the cooling assembly contacts the heat-affected zone of the weld; The axial movement of the steel pipe drives the roller to rotate, and the rotation of the roller drives the striker of the stress relief assembly to strike the weld toe of the steel pipe; The rollers are arranged in pairs on both sides of the weld facing each other, the number of the rollers is at least 2 pairs, and they are arranged longitudinally along the weld; the axes of the rollers are perpendicular to the axis of the steel pipe; The cooling assembly is connected to the rocker of the four-bar linkage through a connecting plate, the upper end of the guide screw fixedly mounted on the connecting plate passes through the through hole of the rocker and is fixed by a nut, and a compression spring I is installed on the guide screw between the connecting plate and the rocker; The upper end of the bracket of the cooling assembly is fixedly connected to the connecting plate; The roller and the water slip ring are sequentially installed on the side of the bracket, the stator of the water slip ring is fixedly connected to the bracket, and the rotor of the water slip ring is fixedly connected to the roller; The stator and the rotor are provided with water flow channels, which are connected with the cavity of the roller; The upper end of the guide column of the stress relief assembly is fixedly installed with a nut after passing through the through hole of the bracket; a baffle is fixedly installed in the middle of the guide column, and a compression spring II is axially installed on the guide column between the bracket and the baffle, and the guide column moves up and down along the through hole of the bracket; The roller end surface is provided with more than two shifting blocks at intervals along the circumference; when the roller rotates, the shifting blocks shift the baffle to control the guide column to move up and down, and the striker at the lower end of the guide column strikes the weld toe of the steel pipe.

2. The device for cooling the weld seam of a submerged arc welded steel pipe and reducing residual stress according to claim 1, characterized in that: The cooling water system includes a water chiller, a water inlet pipeline, and a water outlet pipeline, and the cooling water system provides circulating cooling water to the roller of the cooling assembly; The circulating cooling water is supplied by a water chiller, and enters the roller cavity through the water inlet pipeline, the stator's water inlet channel, and the rotor's water inlet channel in sequence, and then flows out through the rotor's water outlet channel, the stator's water outlet channel, and the water outlet pipeline in sequence.

3. The device for cooling the weld seam and reducing residual stress of a submerged arc welded steel pipe according to claim 2, characterized in that: The water inlet channel and the water outlet channel of the stator are communicated with the water inlet pipeline and the water outlet pipeline respectively.

4. The device for cooling the weld seam of a submerged arc welded steel pipe and reducing residual stress according to claim 1, characterized in that: The cooling assembly is arranged behind the welding gun.

5. The device for cooling the weld seam and reducing residual stress of a submerged arc welded steel pipe according to claim 1, characterized in that: The four-bar linkage is driven by a cylinder; the rocker is a flat plate; there are two groups of connecting rod frames, which are symmetrically arranged on both sides of the longitudinal axis of the rocker.

6. The device for cooling the weld seam and reducing residual stress of a submerged arc welded steel pipe according to claim 1, characterized in that: The number of the shifting blocks fixedly installed on the end surface of the roller is 4 to 6 and is evenly distributed along the circumference.

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