API 510 Material Evaluation 2

Question 1

When evaluating a pressure vessel for hydrogen-induced cracking (HIC), which metallurgical factor most significantly influences susceptibility?

Accepted Answer

Sulfur content and sulfide inclusion morphology

Answer

Sulfide inclusions, particularly elongated MnS inclusions, are the primary initiation sites for HIC in pressure vessel steels.

Question 2

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?

Accepted Answer

Yield strength, tensile strength, and elongation

Answer

MTRs must confirm yield strength, tensile strength, and elongation as minimum mechanical properties per ASME Section II requirements.

Question 3

A carbon steel vessel operating in wet H2S service shows blistering on the internal surface. What is the primary mechanism causing this damage?

Accepted Answer

Atomic hydrogen diffusing into the steel and recombining at discontinuities

Answer

In wet H2S service, atomic hydrogen diffuses into the steel and recombines as molecular hydrogen at internal voids, creating blisters through pressure buildup.

Question 4

According to API 510, what action is required when the actual material of a vessel component cannot be positively identified?

Accepted Answer

Test the material using PMI or other methods, or assume the lowest-grade material

Answer

When material cannot be identified, API 510 requires PMI or other testing, or the inspector must assume the lowest-strength material for calculations.

Question 5

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?

Accepted Answer

Temper embrittlement

Answer

Cr-Mo steels in the temperature range of 650-1100°F are susceptible to temper embrittlement from segregation of tramp elements to grain boundaries.

(API 510) API 510 Inspector Certification Practice Test

(API 510) API 510 Inspector Certification Practice Test

API 510 Material Evaluation 2