Back-gouging-free spot-welding-free assembling method for spherical tank

Abstract

The invention discloses a back-gouging-free spot-welding-free assembly method for a spherical tank, which comprises the following steps of: assembling the spherical tank by adopting a fixture, formally adjusting a seam to meet the standard requirement, assembling and positioning the spherical tank by adopting a connecting plate, mounting a ceramic gasket on a back welding side, and not needing in-groove welding, so that after the first welding side (the front surface of a welding seam) of the spherical tank is welded, the welding side is welded, and the welding side is welded; and back gouging polishing is simply carried out on the rear welding side (the back face of the welding seam), and double-face welding of the welding seam is achieved. According to the welding method, after the front face of the spherical tank is welded, cleaning of the weld groove in the back face of the spherical tank can be completed through simple back face coping, the geometric dimension of the groove is not damaged, gouging back gouging and repairing are not needed, and the groove size and quality requirements needed by automatic welding of the spherical tank are easily met. By means of the method, damage to the root of the weld joint is small, grinding and repair welding operation is easy, the shape of the groove before welding is remarkably improved, and the welding quality and construction efficiency of automatic welding are guaranteed.

Description

Technical Field

[0001] This invention relates to a method for assembling spherical tanks without root cleaning or spot welding, belonging to the field of spherical tank welding construction technology. Background Technology

[0002] With the in-depth research and continuous development of automatic welding technology for spherical storage tanks, higher requirements have been placed on the assembly precision of the spherical tank shell plates. The smooth implementation of automatic welding of spherical tanks and ensuring the uniformity of bevel dimensions are crucial factors for achieving both quality and efficiency improvements. In existing technologies, a tack welding process is generally used before spherical tank assembly welding. This involves adjusting the weld gap and misalignment of the shell plates using jigs after the tank is hoisted, followed by intermittent temporary reinforcement welding on the back of the jigs to fix the tank in place before overall welding. This reinforcement welding method alters the original geometry of the bevel. Completely restoring the original bevel dimensions requires significant manual labor for air gouging, repair welding, and grinding, making it difficult to restore the original bevel shape and resulting in long construction periods and high costs. Furthermore, this temporary reinforcement welding method is highly detrimental to the welding quality of automatic spherical tank welding, easily causing various welding defects. Therefore, there is an urgent need for a positioning construction process that can reinforce the spherical shell plate of the spherical tank without changing the bevel, avoid the welding defects of automatic welding of spherical tanks, and realize the efficient and comprehensive application of automatic welding technology for spherical tanks. Summary of the Invention

[0003] The purpose of this invention is to provide a method for assembling spherical tanks without root cleaning or spot welding, which solves the technical problem that the existing temporary reinforcement welding cannot meet the high requirements of the bevel assembly accuracy and bevel shape of spherical tanks for automatic welding. This method aims to reduce the difficulty of bevel treatment, improve the welding quality of spherical tanks, save construction time, and reduce construction costs.

[0004] The present invention adopts the following technical solution: a method for assembling a spherical tank without root cleaning and spot welding, comprising the following steps: (1) after the spherical tank is assembled, the shell plates are assembled on the rear welding side of the spherical tank using jigs and fixtures, and the gap and misalignment of the shell plates are adjusted; (2) a connecting plate is welded on the rear welding side of the spherical tank, and the connecting plate is welded on the shell plates on both sides of the weld to reinforce the weld of the spherical tank; (3) the jigs and fixtures are removed; (4) a ceramic gasket is installed in the weld bevel on the rear welding side, and the weld is sealed with the ceramic gasket; (5) the weld is welded on the first welding side of the spherical tank, and after the weld on the first welding side is completed, the connecting plate and ceramic gasket on the rear welding side are removed; (6) the root and bevel of the weld on the rear welding side are ground and non-destructive testing is performed, and then the weld is welded on the rear welding side to finally complete the welding of the entire weld.

[0005] In step (1), temporary assembly square caps are welded to the edges of two adjacent spherical shell plates on the back welding side. The square caps are 150mm away from the edge of the spherical shell plate, and the distance between the square caps on the two adjacent spherical shell plates is less than 1200mm. The number of square caps on the short side of the spherical shell plate in the equatorial zone of the spherical tank is not less than 4 pieces. The spherical tank fixture is clamped on the temporary assembly square caps, and the spherical shell plates are assembled and the joints are adjusted. The assembly gap of the spherical shell plates is 3-5mm, and the misalignment is less than 0.5mm.

[0006] In step (2), the welding of the connecting plate and the spherical shell plate adopts the form of C-type weld. The connecting plate is adjusted and symmetrically welded to the spherical shell plate on both sides of the weld during the assembly of the weld.

[0007] In step (2), the connecting plate has dimensions of 16mm×200mm×70mm, the material of the connecting plate is the same as that of the spherical tank, and the weld leg height of the connecting plate is greater than 12mm.

[0008] The connecting plate includes a horizontal positioning plate and a vertical positioning plate. One vertical positioning plate is installed every 1.3m, and one or two horizontal positioning plates are added between two vertical positioning plates.

[0009] In step (4), ceramic rods are used as ceramic backings. The ceramic rods are inserted one by one into the weld groove, and the ceramic rods are in close contact with the root of the weld, with adjacent ceramic rods in close contact with each other.

[0010] The ceramic rod has a diameter of Φ6mm and a length of 600mm.

[0011] In step (3), after the connecting plate is welded, the spherical tank fixture is removed, the square cap is ground off with a grinding wheel, and then the weld scars after the fixture is removed are ground flat and the pits are repaired by welding.

[0012] In step (5), after the weld on the first weld side is completed, use an air gouger or a grinding wheel to remove the connecting plate on the back side, take out the ceramic backing from the second weld side, grind the weld scar flat, and weld the pit.

[0013] In step (6), before the weld on the welded side after welding, the weld bevel on the welded side is ground with a grinding wheel. After completion, the root of the weld on the welded side is cleaned and the bevel is cleaned.

[0014] The beneficial effects of this invention are as follows: After assembling the ball tank using jigs and fixtures and ensuring the seam meets specifications, the ball tank is positioned using a connecting plate. A ceramic gasket is installed on the back welding side, eliminating the need for welding within the bevel. Furthermore, after welding the first welding side (the front of the weld), a simple root cleaning and grinding process is performed on the second welding side (the back of the weld), achieving double-sided welding. This construction process allows for the cleaning of the back weld bevel after simple back grinding following front welding of the ball tank, without damaging the bevel geometry. No air gouging or repair is required, easily achieving the bevel size and quality requirements for automatic ball tank welding. This invention minimizes damage to the weld root, simplifies grinding and repair welding operations, significantly improves the pre-welding shape of the bevel, and ensures welding quality and construction efficiency in automatic welding.

[0015] Preferably, the size and spacing of the connecting plates can be adjusted appropriately, and the connecting plate material is easy to manufacture.

[0016] Preferably, the shape and size of the ceramic gasket can be adjusted according to the weld gap. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a connecting plate connected to both sides of a spherical shell plate in one embodiment of the present invention; Figure 2 This is a schematic diagram of the installation of the ceramic gasket in one embodiment of the present invention.

[0018] In the diagram: 1-Assembly fixture; 2-Ceramic liner; 3-Connecting plate; 4-Square cap; 5-Weld; 7-Spherical shell plate. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0020] An embodiment of the present invention provides a method for assembling a spherical tank without root cleaning or spot welding. First, the spherical shell plates 7 of the spherical tank are hoisted and all the spherical shell plates of the spherical tank are hoisted into place according to the drawing requirements. Then, the following steps are performed: (1) After the spherical tank is assembled, a square cap 4 and an assembly jig 1 are used to temporarily fix the spherical tank. That is, the jig is used on the rear welding side of the spherical tank to assemble the shell plates and adjust the assembly gap and misalignment of the shell plates 7. Specifically, in this step, temporary assembly square caps 4 are welded to the edges of two adjacent shell plates 7 on the rear welding side. The square caps are 150mm away from the edge of the shell plate, and the distance between the square caps 4 on the two adjacent shell plates is 900mm (in other embodiments, the distance between the square caps can be set as needed. Usually, the distance between the square caps on the two adjacent shell plates is less than 1200mm). The number of square caps on the short side of the shell plate of the equatorial zone of the spherical tank is not less than 4 pieces. The spherical tank jig is clamped on the temporary assembly square caps to assemble and adjust the gap of the shell plates. The assembly gap of the shell plates is 3-5mm and the misalignment is less than 0.5mm.

[0021] The spherical tank weld is a double-sided X-groove, divided into a first-welding side and a second-welding side. The first-welding side corresponds to the front of the weld, and the second-welding side corresponds to the back of the weld. This step involves arranging workers to adjust the weld seam of the spherical tank to ensure that the weld seam assembly gap, misalignment, and edge angle meet the requirements of the drawings and specifications. The adjustment sequence is: equatorial plate - temperate plate - upper and lower polar plates - circumferential seam between temperate plate and upper and lower polar plates - circumferential seam between equatorial plate and temperate plate.

[0022] (2) Weld connecting plate 3 to the rear weld side of the spherical tank. Connecting plate 3 is welded to the spherical shell plates 7 on both sides of the weld to reinforce the weld of the spherical tank. A schematic diagram of the reinforcement of the connecting plate is shown below. Figure 1 As shown. In this step, the welding of connecting plate 3 and spherical shell plate 7 adopts a C-type weld. The connecting plate is symmetrically welded to the spherical shell plate on both sides of the weld using jigs and adjustment during the weld assembly process. The connecting plate dimensions are 16mm × 200mm × 70mm, and the material of the connecting plate is the same as that of the spherical tank. The weld leg height of the connecting plate is greater than 12mm. The connecting plate includes horizontal and vertical mounting plates. One vertical mounting plate is installed every 1.3m, and 1-2 horizontal mounting plates are added between two vertical mounting plates. At the longitudinal welds of the spherical tank (welds between equatorial plates and temperate plates) and the welds of the upper and lower electrode plates, the distance between two adjacent connecting plates is 600mm; at the circumferential welds, the distance between two adjacent connecting plates is 400mm.

[0023] The installation sequence of connecting plate 3 is the same as the joint adjustment sequence in step (1). The joint adjustment can be performed while installing connecting plate 3. The connection method in this step is to semi-enclose C-shaped welding at both ends of the connecting plate. The connecting plate and the welding structure are as follows: Figure 1 As shown.

[0024] (3) Remove the jigs and fixtures: After the connecting plate is welded, remove the jigs and fixtures of the spherical tank, grind off the square cap with a grinding wheel, grind the weld scars after the jigs and fixtures are removed, and weld the pits.

[0025] (4) Install ceramic gasket 2 in the weld groove on the post-weld side to seal the weld. The ceramic gasket 2 is made of ceramic rods. Insert the ceramic rods one by one into the weld groove. The ceramic rods 2 are in close contact with the root of the weld, and adjacent ceramic rods are in close contact to avoid gaps. The ceramic rods used in this embodiment have a diameter of Φ6mm and a length of 600mm.

[0026] (5) Weld the weld 5 on the first weld side of the spherical tank. After the weld on the first weld side is completed, remove the connecting plate and ceramic gasket on the second weld side. Specifically, use an air gouger or a grinding wheel to remove the connecting plate on the back, take out the ceramic gasket from the second weld side, grind the weld scar flat, and weld the pit.

[0027] (6) Before welding the weld 5 on the post-weld side, use a grinding wheel to grind the weld bevel on the post-weld side. After that, clean the root and bevel of the weld 5 on the post-weld side. After grinding the root and bevel of the post-weld side, perform non-destructive testing. Then weld the weld on the post-weld side to complete the welding of the entire weld.

[0028] The construction process described in the above embodiment uses connecting plates to reinforce the weld seams of the spherical tank and ceramic gaskets to protect the weld root. This ensures that the weld bevel size remains intact, which is beneficial for welding with automatic welding equipment. It also reduces the need for root cleaning and grinding, ensures welding quality, and improves construction efficiency. This method has reference value for the entire spherical tank construction industry.

[0029] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the scope of protection of the present invention in any way, and all technical solutions obtained by equivalent substitution or other means fall within the scope of protection of the present invention.

Claims

1. A method for assembling a spherical tank without root cleaning or spot welding, characterized in that, It includes the following steps: (1) After the spherical tank is assembled, the shell plates are assembled on the rear welding side of the spherical tank using jigs and fixtures, and the gap and misalignment of the shell plates are adjusted. (2) A connecting plate is welded on the rear welding side of the spherical tank. The connecting plate is welded on the shell plates on both sides of the weld to reinforce the weld of the spherical tank. (3) The jigs and fixtures are removed. (4) A ceramic gasket is installed in the weld bevel on the rear welding side to seal the weld. (5) The weld is welded on the first welding side of the spherical tank. After the weld on the first welding side is completed, the connecting plate and ceramic gasket on the rear welding side are removed. (6) The root and bevel of the weld on the rear welding side are ground and non-destructive testing is performed. Then the weld is welded on the rear welding side to complete the welding of the entire weld.

2. The method for assembling spherical tanks without root cleaning and spot welding according to claim 1, characterized in that: In step (1), temporary assembly square caps are welded to the edges of two adjacent spherical shell plates on the back welding side. The square caps are 150mm away from the edge of the spherical shell plate, and the distance between the square caps on the two adjacent spherical shell plates is less than 1200mm. The number of square caps on the short side of the spherical shell plate in the equatorial zone of the spherical tank is not less than 4 pieces. The spherical tank fixture is clamped on the temporary assembly square caps, and the spherical shell plates are assembled and the joints are adjusted. The assembly gap of the spherical shell plates is 3-5mm, and the misalignment is less than 0.5mm.

3. The method for assembling spherical tanks without root cleaning and spot welding according to claim 1, characterized in that: In step (2), the welding of the connecting plate and the spherical shell plate adopts the form of C-type weld. The connecting plate is adjusted and symmetrically welded to the spherical shell plate on both sides of the weld during the assembly of the weld.

4. The method for assembling spherical tanks without root cleaning and spot welding according to claim 1, characterized in that: In step (2), the connecting plate has dimensions of 16mm×200mm×70mm, the material of the connecting plate is the same as that of the spherical tank, and the weld leg height of the connecting plate is greater than 12mm.

5. The method for assembling spherical tanks without root cleaning and spot welding according to claim 1, characterized in that: The connecting plate includes a horizontal positioning plate and a vertical positioning plate. One vertical positioning plate is installed every 1.3m, and one or two horizontal positioning plates are added between two vertical positioning plates.

6. The method for assembling a spherical tank without root cleaning and spot welding according to claim 1, characterized in that: In step (4), ceramic rods are used as ceramic backings. The ceramic rods are inserted one by one into the weld groove, and the ceramic rods are in close contact with the root of the weld, with adjacent ceramic rods in close contact with each other.

7. The method for assembling a spherical tank without root cleaning and spot welding according to claim 6, characterized in that: The ceramic rod has a diameter of Φ6mm and a length of 600mm.

8. The method for assembling a spherical tank without root cleaning and spot welding according to claim 1, characterized in that: In step (3), after the connecting plate is welded, the spherical tank fixture is removed, the square cap is ground off with a grinding wheel, and then the weld scars after the fixture is removed are ground flat and the pits are repaired by welding.

9. The method for assembling a spherical tank without root cleaning and spot welding according to claim 1, characterized in that: In step (5), after the weld on the first weld side is completed, use an air gouger or a grinding wheel to remove the connecting plate on the back side, take out the ceramic backing from the second weld side, grind the weld scar flat, and weld the pit.

10. The method for assembling a spherical tank without root cleaning and spot welding according to claim 1, characterized in that: In step (6), before the weld on the welded side after welding, the weld bevel on the welded side is ground with a grinding wheel. After completion, the root of the weld on the welded side is cleaned and the bevel is cleaned.

Images