Material Evaluation 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 Material Evaluation flashcards as text
When evaluating a pressure vessel for hydrogen-induced cracking (HIC), which metallurgical factor most significantly influences susceptibility?
Answer: Sulfur content and sulfide inclusion morphology
Sulfide inclusions, particularly elongated MnS inclusions, are the primary initiation sites for HIC in pressure vessel steels.
An API 510 inspector is reviewing mill test reports (MTRs) for a replacement shell course. Which property must be verified to confirm the material meets ASME Section II requirements?
Answer: Yield strength, tensile strength, and elongation
MTRs must confirm yield strength, tensile strength, and elongation as minimum mechanical properties per ASME Section II requirements.
A carbon steel vessel operating in wet H2S service shows blistering on the internal surface. What is the primary mechanism causing this damage?
Answer: Atomic hydrogen diffusing into the steel and recombining at discontinuities
In wet H2S service, atomic hydrogen diffuses into the steel and recombines as molecular hydrogen at internal voids, creating blisters through pressure buildup.
According to API 510, what action is required when the actual material of a vessel component cannot be positively identified?
Answer: Test the material using PMI or other methods, or assume the lowest-grade material
When material cannot be identified, API 510 requires PMI or other testing, or the inspector must assume the lowest-strength material for calculations.
A vessel fabricated from SA-387 Grade 11 (1.25Cr-0.5Mo) steel is being evaluated after long-term service at 850°F. What material degradation mechanism is the primary concern?
Answer: Temper embrittlement
Cr-Mo steels in the temperature range of 650-1100°F are susceptible to temper embrittlement from segregation of tramp elements to grain boundaries.
When using Positive Material Identification (PMI) to verify alloy content, which technique provides elemental analysis that can detect carbon content?
Answer: Optical emission spectrometry (OES)
OES (spark testing) can detect carbon content, while XRF cannot reliably measure carbon due to the low atomic number limitation of most portable XRF units.
A reactor vessel in high-temperature hydrogen service is being evaluated against the Nelson Curves. The operating condition falls above the applicable curve. What does this indicate?
Answer: The material is susceptible to high-temperature hydrogen attack (HTHA)
Operating above the Nelson Curve for a given material indicates susceptibility to HTHA, where hydrogen reacts with carbides causing decarburization and fissuring.