Inspection Techniques & Nondestructive Testing Flashcards
7 cards from real API 510 practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Inspection Techniques & Nondestructive Testing flashcards as text
A hydrogen-induced cracking (HIC) inspection of a carbon steel vessel operating in wet H₂S service should prioritize which NDT technique?
Answer: Straight beam UT or phased array UT to detect internal laminar cracking
HIC produces internal laminar cracks parallel to the plate surface; straight beam UT effectively detects these by identifying loss of back-wall reflection or anomalous mid-wall indications.
Guided wave ultrasonic testing (GWUT) is used in pressure vessel piping inspections primarily to:
Answer: Screen long lengths of pipe for corrosion anomalies from a single probe position
GWUT propagates low-frequency waves along the pipe axis, allowing a single probe to screen tens of meters of pipe for corrosion, erosion, or other wall-loss anomalies.
When using phased array ultrasonic testing (PAUT) for weld inspection, which advantage does it offer over conventional single-element UT?
Answer: Provides multiple beam angles simultaneously with electronic scanning
PAUT electronically steers and focuses multiple beam angles without physically moving the probe, enabling faster scanning and improved flaw characterization compared to single-element UT.
During an internal visual inspection of a pressure vessel, the inspector observes a deposit of orange-brown scale on the bottom head. The most likely cause and recommended follow-up is:
Answer: Iron oxide from general corrosion; perform UT thickness readings under and near the deposit
Orange-brown scale is typically iron oxide corrosion product; UT should be performed under and around the deposit to quantify metal loss beneath it.
What does the term 'remaining life' mean in the context of API 510 inspection planning?
Answer: The estimated time before the vessel wall reaches minimum allowable thickness at the measured corrosion rate
Remaining life is calculated by dividing the difference between current thickness and minimum allowable thickness by the corrosion rate, giving the estimated time before retirement.
Thermoelectric (spark) testing is sometimes used during vessel fabrication inspection to verify:
Answer: That the correct alloy material has been used (positive material identification)
Thermoelectric testing (along with XRF and OES) is a form of positive material identification (PMI) that distinguishes alloy families by their thermoelectric signature against a reference material.
An inspector is evaluating a pressure vessel for fitness-for-service after finding a blister from hydrogen damage. Per API 579-1/ASME FFS-1, the first assessment level for HIC/SOHIC involves:
Answer: Applying screening criteria based on blister dimensions relative to vessel geometry
Level 1 FFS assessment for HIC/blistering uses prescriptive screening rules comparing blister size, depth, and proximity to welds against acceptance criteria without requiring complex stress analysis.