Welding and Nondestructive Examination
Welding and NDE questions test the chain of qualification and the separation of method from acceptance.
Section IX: three documents
- WPS - the written procedure the shop works to.
- PQR - the record of the test coupon that qualified the procedure, with essential variables recorded.
- WPQ - the individual welder's or operator's performance qualification.
Essential variables include P-number, thickness, position, filler F-number, preheat, and postweld heat treatment. A coupon of thickness T typically qualifies base metal from 1/16 in. up to 2T, so a thin coupon cannot cover heavy work. Welder qualification lapses after six months without welding with that process, so the AI checks continuity, not just the original certificate.
Section V: method, not acceptance
Section V describes how to perform RT, UT, PT, MT, visual, and leak testing, and requires NDE personnel to be qualified under a written practice such as SNT-TC-1A (Level II or III) or CP-189. Acceptance criteria come from the construction code: Section VIII Div. 1 UW-51 for full radiography, UW-52 for spot, with UW-12 joint efficiencies of 1.00 (full RT), 0.85 (spot), and 0.70 (none) for a Type 1 double-welded butt joint. Spot examination covers at least 1 ft of weld per 50 ft, per welder.
Worked example. A Div. 1 data report claims E = 1.00 on a 1 in. shell, but the RT report shows spot radiography only. Reasoning: E = 1.00 requires full radiography of the categories credited; spot examination supports only 0.85. Either radiography is extended to full coverage or the design is rechecked at 0.85. The AI cannot sign as submitted.
Traps. Citing Section V as the acceptance standard; accepting a WPS whose PQR covers a different P-number or an out-of-range thickness; missing a lapsed welder qualification; confusing spot examination coverage with full radiography.