API-571 Exam Dumps : Corrosion and Materials Professional

Under Thermal Fatigue and Shock, API RP 571 explains:

“Thermal shock damage often initiates at locations with sudden temperature changes, such as quench zones, cold/hot injection points, and areas subjected to rapid cycling.”

“These are critical inspection points for detecting cracking from thermal shock.”

Thus, option B best matches the described mechanism.

API RP 571 – Polythionic Acid Stress Corrosion Cracking:

“Polythionic acid SCC may be mistaken for wet H₂S damage because both involve cracking in austenitic stainless steels under certain conditions.”

Thus, option D is correct.

Comprehensive and Detailed Explanation From Exact Extract:

According to API RP 571, carbon steel exhibits a minimum corrosion rate in sulfuric acid at concentrations around 65–70 wt% due to formation of a protective iron sulfate film.

When sulfuric acid concentration drops below approximately 65%, this protective film becomes unstable and corrosion rates increase dramatically.

Referenced Documents (Study Basis):

API RP 571 – Section on Sulfuric Acid Corrosion

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