API API-571 Exam With Confidence Using Practice Dumps

According to API RP 571 Section 5.1.2.1 (Hydrogen-Induced Cracking) and Publ 939-A, blistering in carbon and low alloy steels exposed to wet H2S environments can be exacerbated by the presence of cyanides. These accelerate hydrogen entry into steel, increasing the chance of hydrogen blistering.

API RP 571 states:

“HIC and blistering are forms of hydrogen damage that occur in wet H2S environments. The presence of cyanides can significantly increase hydrogen entry and the risk of blistering.”

Publ 939-A (Research on Cracking in Wet H2S Service) also notes:

“Cyanides act as catalytic agents in hydrogen charging, which promotes internal pressure build-up and increases blistering.”

Thus, cyanides (Option B) are the most critical in enhancing blistering in H2S environments.

According to API RP 571, high-cycle fatigue (HCF) is characterized by very tight, narrow cracks that can escape detection using typical NDE methods due to their minimal opening displacement and fine geometry.

From API RP 571 Section 5.2.1 (Fatigue - High Cycle):

"The cracks are usually tight and may be difficult to detect using conventional NDE techniques such as PT or MT. UT and RT may also have difficulty identifying these small, tight flaws, especially in early stages of propagation."

The primary issue in NDE is not the geometry (such as 90° corners) or ID location, but rather the tightness and early-stage subtlety of the cracks which results in reduced detectability. Therefore, option B is correct as it aligns most accurately with API RP 571's detailed characterization of HCF detection challenges.

According to API RP 571 Section 5.3.2.3 (Spheroidization):

“Spheroidization is a microstructural degradation that occurs in carbon steels and low alloy steels when exposed to elevated temperatures for long periods, typically beginning at temperatures as low as 650°F (345°C). It involves the transformation of lamellar pearlite into spherical cementite particles, reducing strength and hardness.”

Thus, Option A (650°F / 345°C) is the minimum threshold temperature for spheroidization to begin.