(RT testing) It’s not possible to take X-rays of the nozzles on the container, so why is it possible to do so for the pipes?
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GB150 stipulates that when the nominal diameter of the vessel’s nozzles is greater than 250 mm, their Class A welds must be inspected in the same manner as the Class A welds of the vessel’s shell. The exact wording is: “For nozzles in the vessel with a nominal diameter of ≥250 mm, as well as for the joints formed by the nozzles and the high-neck welded flanges, the inspection requirements are the same as those for Class A and Class B weld joints.” ” The reason is that negative films cannot be placed in small pipes (under DN250). So the question is: Why can all welds on pipes be inspected using RT100%? Can very thin pipes also be inspected this way?
Where did the original poster get the idea that “the reason is that small pipes (smaller than DN250) cannot accommodate the bottom sheet”? GB150 doesn’t mean that at all!
How is it possible to take X-rays of takeover fillet welds? They are all PT
This is just my guess. Please let me know what it really means
In my opinion, the stress on the equipment connection flanges is different from that on the pipes; the pipes are subject mainly to vibration
This should be in accordance with ASME regulations; you can check Volume 8, Chapter 1. Additionally, RT testing is permissible for butt welds of fittings and flanges that are less than 250 in size. One of our clients has been insisting that we use RT testing for such small fittings
The reason is that negative films cannot be placed in small pipes (under DN250). I’ve never seen an explanation for this reason. . . .
The pipe ends with a diameter of less than 250 shall comply with the requirements in the drawings. When shooting microtubes, the film is placed on the outside, so even the tiniest details can be captured.
GB150-2011 does not specify in writing that no radiographic testing is required for fittings with DN＜250mm due to the inability to place a film; the proportion of non-destructive testing for the butt joints of such fittings is determined according to the provisions in the design documents.
From the perspective of radiographic inspection, not to mention DN200, even DN20 and DN15 can be radiographed. Additionally, both GB20801 and SH3501 require RT testing for branch pipe connections (i.e., pipe joint welds) larger than 100 in high-grade pipelines. The testing difficulty of branch pipe joints is slightly greater than that of butt joints. So, it’s highly likely that it’s not due to limitations in detection technology.