What should I do if the flange grade is welded wrongly?
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On-site issues: What should I do if the flange grade is welded wrong? There is a vertical container on site with two inlets.: A1 and A2 are both 3 inches. The pressure level of nozzle A1 should be 150bl and A2 should be 300bl. As a result, the manufacturer welded the two flanges incorrectly for some unknown reason. A1 became 300bl and A2 became 150bl. Please advise on the solution? It should be no problem to replace A1 with a large one, but I don't know if it can be matched with external piping? A2 Is it okay if we cut it off on site and re-weld a 300bl flange? What other issues should we pay attention to? Do I need to redo the hydrostatic test?
1. There is no problem with the outer straightness of the pipes, both are 88.9, it depends on whether the thickness is suitable. 2. For high-generation and low-generation pipes, they need to be equipped with matching flanges of the same level. 3. Replace A2, there is no problem, but you need to pay attention.: Try to remove all the original welding seals. The original heat treatment requirements need to be redone, and non-destructive testing must also be met. In principle, pressure vessels need to be carried out in accordance with specifications.
It is best to match the pipe flange with the equipment flange. If there are two pressure levels, first check whether the circle diameters of the bolt holes of the two flanges are the same to ensure that they can be connected. If the equipment flange is replaced, if the pressure vessel requires re-acceptance/inspection by the relevant department, a hydrostatic test is necessary.