This article describes ASME Section IX Radiography requirements. The RT acceptance criteria that have been addressed on QW- 188.8.131.52 refers to the welder or welding operator performance qualification. This acceptance criterion should not be confused with actual work radiographic testing acceptance criteria.
This acceptance criteria is stricter than for actual welding work that addressed in UW-51 (Full Radiography) and UW-52 (Spot Radiography). This stringency seems reasonable because with this acceptance criteria we are testing the skill of our welder and not actual welding work.
So it possible a weld seam radiographic testing to be rejected by the criteria in ASME Code Section IX but being acceptable based on the UW-51 on the ASME Section VIII Div 1.
So please make sure when you are interpreting a radiograph for welder performance qualification refer to the section IX and when it is an actual work, e.g., long, or girth seam of a pressure vessel refer to the section VIII.
Based on the requirements of QW-184.108.40.206 in ASME Section IX any crack and incomplete fusion is unacceptable.
The length of elongated inclusion depends on the test piece thickness, for instance, any elongated slag inclusion will be unacceptable if the length is more than 1/8 inch when the thickness of the specimen is between 0 to 3/8 inch.
Similarly, one-third of test specimen thickness if the specimen thickness between 3/8 inch (over) to 2 1/4 inch.
The maximum allowable rounded indication is 1/8 inch or 20 % of thickness whichever is smaller, and if there is cluster pattern then Figure QW-220.127.116.11(b)(4) must be referred. This figure shows the acceptance criteria for porosity (rounded indication) dispersion level.
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