Sources used:
- GB/T 20801.5-2020 summary, Code of China
- NB/T 47013.2 radiographic testing summary, Code of China
- ASNT Introduction to Nondestructive Testing
Why This Question Matters
A common buyer question is: "Under GB rules, what percentage of pressure piping welds must receive RT?" The safe answer is not a single number. The required radiographic testing percentage depends on the piping code, design document, pipe class, weld type, service fluid, pressure-temperature condition, inspection class, and project specification.
For pipe fittings and prefabricated spools, this matters because a supplier cannot honestly quote inspection cost or delivery time from the words "GB RT inspection" alone. The RFQ must define what method is required, where it applies, what acceptance criteria are used, and what reports must be submitted.
