API API-571 Dumps Questions Answers

API RP 571 discusses Hydrogen-Induced Cracking (HIC) and Blistering:

“Postweld heat treatment (PWHT) does not significantly reduce susceptibility to HIC, as the mechanism is primarily driven by hydrogen charging in wet H₂S environments and steel cleanliness, not residual stresses.”

“PWHT is more effective for SSC, SOHIC, and other stress-driven mechanisms.”

Thus, HIC will not benefit much from PWHT, making option C correct.

API RP 571 notes that for detecting existing cracks or flaws that may lead to brittle fracture, especially those that initiate at welds or surface stress points:

“Wet fluorescent magnetic-particle inspection is highly effective for detecting surface-breaking flaws in ferromagnetic materials that are susceptible to brittle fracture.”

“It is sensitive to tight cracks and surface discontinuities that may serve as initiation sites for brittle fracture.”

(Reference: API RP 571, Section 4.2.1.2 – Brittle Fracture)

Therefore, option A is correct as it is the most effective NDE technique for detecting early signs of brittle cracking.

From API RP 571 and RP 932-B:

“In hydroprocessing reactor effluent systems, the most common corrosion mechanism is ammonium bisulfide (NH₄HS) corrosion, which forms in the presence of hydrogen sulfide and ammonia.”

“NH₄HS attacks carbon steel aggressively under turbulent flow and at low pH.”

Correct answer is B – ammonium bisulfide corrosion.