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Upholding the corporate spirit of “Integrity, Harmony, Pragmatism, and Innovation,” we remain committed to a business philosophy that puts people first, embraces technological innovation, and emphasizes integrity and pragmatism.
A detailed introduction to the specific use of bellows expansion joints.
Release time:
Dec 08,2021
During the assembly and welding process of bellows expansion joints, the following items should be inspected: Bellows expansion joints are commonly used pipeline components that play a significant role in piping systems. During the assembly and welding process of bellows expansion joints, the following items should be inspected: The dimensional tolerances for the inner and outer diameters of the straight sections of the bellows shall meet the requirements of Grade H12 (or h12) specified in GB 1804.
During the assembly and welding process of bellows expansion joints, the following items should be inspected: Bellows expansion joints are commonly used pipeline components that play a significant role in piping systems. During the assembly and welding process of bellows expansion joints, the following items should be inspected: The dimensional tolerances for the inner and outer diameters of the straight sections of the bellows shall meet the requirements of Grade H12 (or h12) specified in GB 1804.
The dimensions and technical requirements for the flanges and end pipes connecting the bellows compensator to the pipeline (or equipment) shall comply with the relevant standards. When connecting with end pipes, the openings at both ends shall be beveled at an angle of 30° ± 2.5°. If the end pipes of the bellows compensator are fabricated from steel plates by rolling and electric welding, the tolerances for the outer circumference and roundness of the end pipe’s external connection port shall conform to the relevant regulations.
The circumferential welds connecting the bellows to end pipes (or flanges) shall be made by tungsten inert gas (TIG) welding or metal inert gas (MIG) welding. When the single-layer wall thickness of the bellows exceeds 2 mm, arc welding may be used. During the assembly of bellows compensators, protective measures must be taken to prevent the welding arc from burning through the bellows and to avoid welding slag from splashing onto the bellows. The welds in all parts of the compensator must be free from defects such as cracks, porosity, and slag inclusions; the depth of undercutting shall not exceed 0.5 mm.
After welding the pressure-bearing welds of the corrugated expansion joint, a pressure test shall be conducted on these welds at a test pressure equal to 1.5 times the design pressure. Depending on the volume of the expansion joint, hold the pressure for 10 to 30 minutes, and inspect all parts of the expansion joint for any leaks. During pressurization, the ratio of the wave pitch under pressure to the wave pitch before pressurization shall not exceed 1.15.7. After the expansion joint assembly is welded, it shall undergo visual inspection and verification of geometric dimensions.
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