Welding quality requirements for acetylene pipelines (operating pressure 4–7 KPa)
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It was found at the site that the valves used on the acetylene pipelines were gate valves, welding was done using full electric welding, and socket flanges were used; is this permitted according to the standards? Are there any regulations regarding this?
There is a large amount of lack of penetration and depressions at the root of the weld; non-destructive testing shows that it does not meet the requirements. The alignment of the weld joints is far from proper, and no beveling was done, so there are definitely problems with the welding process
If the groove isn’t made, it’s definitely wrong. For low-pressure acetylene pipelines (operating pressure of 0.004 – 0.007 KPa), there are regulatory requirements regarding whether TIG welding for backing is necessary, whether flaw detection is required, and whether they qualify as pressure pipelines.
It’s listed in the pipeline specifications table; it should be GC2, a pipeline that falls within the scope of inspection for those that are flammable and explosive and thus require special supervision
Looking at the comments from the fourth floor, it should be clearly stated in the design documents whether flaw detection is required for this pipeline. Was it designed by them directly? ? ? Or do they not refer to the design documents during construction? ? ?
All pipes of this type require TIG welding as a backing process. This is done not only to ensure the quality of the welds but also to keep the interior of the pipes clean; otherwise, any residual welding slag can pose a hazard
It’s not a pressure pipeline; RT10%, III – I just checked the information.
You should inform the construction party that filming is required; welding in such conditions will definitely not work, and all the results will be defective. It is recommended to have everything repaired!
There is no clear specification or indication as to where it is required to use TIG welding for the root pass
For RT 10% grade III, can most of them not pass either?
Is there no clear specification, or where is it specified, that TIG welding is required for the root pass? But the standards clearly specify the requirements for root weld quality. Isn’t it clearly stated, or where is it specified, that using TIG welding for the root pass means that the quality of the root weld is not guaranteed? ? ? Generally, pipe welding is performed as single-sided welding; defects that occur at the root are difficult to address, and it is hard for manual arc welding to meet the quality requirements for welding at the root