On the non-destructive testing of fillet welds in pressure pipelines
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The relevant standards for non-destructive testing of fillet welds on metal pipes are GB50184 and GB/T20801; however, their provisions differ from each other. For example: For DN100 steam pipes operating at 1.6 MPa, the weld inspection grade for both types of welds is Grade IV. According to GB50184, magnetic particle testing or penetrant testing shall be conducted on fillet welds, with a sampling ratio of 5% ； However, GB/T 20801 does not specify any inspection ratio; the corresponding ratio in the table is marked as “--”. How do you all handle this situation?
In accordance with GB50517, please refer to Section 9.3. This kind of non-toxic, low-pressure fillet weld is not required. GB50184 is very vague in its wording