Flange misalignment.
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The flange of one pipeline in the high-pressure hydrogenation unit is misaligned by 1 cm. I would like to ask the experts: should it be cut off and then realigned? Should we force them into alignment first, and then adjust and secure the supports?
Personal opinion: The simple way is to pull it back to save time
Check whether GBT 38343 installation tolerances are acceptable
It is recommended not to pull the connection forcefully. Pipelines in high-pressure hydrogenation equipment are usually subject to strict requirements; a flange misalignment of up to 1 cm is considered excessive. Forcing the connections together can result in additional stress, poor sealing, and even leaks and safety hazards in the future. The correct approach is: 1. First, investigate and determine the cause of the misalignment – whether it is due to construction errors or stress within the pipeline itself. 2. If it is confirmed that the misalignment is indeed caused by installation errors or welding defects, the area should be cut open for repair, realigned and rewelded to ensure that there are no internal stresses at the flange connection. 3. Install necessary support and fixing measures for the adjusted pipeline to prevent further displacement and misalignment. 4. After the adjustments are completed, non-destructive testing and strength tests must be carried out again to ensure safety and reliability. In summary, the proper and safe approach is to cut it off and reinstall it; pulling it forcefully is not recommended. .
GBT+20801.4-2020 Code for pressure pipelines – Industrial pipelines – Part 4: Fabrication and installation
It seems that the flange surfaces are not parallel either. Find a location where the circumferential position can be adjusted to correct the issue; cut the pipe there, install the flanges, and then tidy up or reweld the cut area of the pipe.
This situation needs to be handled based on the actual conditions. If the stainless steel pipe connected behind the flange is relatively long, it can be secured firmly, as there is room for the stress resulting from misalignment to dissipate, and this will not have any adverse effects on the workpiece. Over time, as the equipment operates and experiences vibrations, these stresses will continue to spread and weaken at each flange connection point. However, if there is not enough length of steel pipe to relieve the stress, or if the structure around the flange connection is complex, with various pipe fittings and welds present, it is recommended to cut it off and weld it again. Complex structures and numerous welds result in more stress within the component, complicating the stress distribution in that area. Once the equipment starts operating, changes in stress cannot be predicted; once stress accumulates in certain areas, it may cause minor leaks at the flange connection, or in severe cases, it can lead to deformation of the component, affecting its strength. If one lacks experience in this area, the safest approach is to cut it off and weld it again. Judging from the pictures, it’s a large-scale project on site, so an extra amount of work like this isn’t a problem.