Corrosion Mechanisms and Monitoring Flashcards
6 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 6 Corrosion Mechanisms and Monitoring flashcards as text
What is the most common form of deterioration in pressure vessels?
Answer: Corrosion from internal or external exposure
Corrosion is the most prevalent deterioration mechanism in pressure vessels, caused by chemical interaction with contained media or the external environment.
What is the corrosion rate used for in API 510 inspections?
Answer: Calculating remaining life and determining next inspection interval
The corrosion rate, combined with current thickness measurements, determines remaining life and establishes appropriate inspection intervals.
What is corrosion under insulation (CUI)?
Answer: Corrosion occurring beneath external insulation due to trapped moisture
CUI occurs when moisture becomes trapped under external insulation, causing accelerated corrosion that is hidden from visual observation.
Which inspection technique is most effective for detecting CUI without removing insulation?
Answer: Profile radiography or pulsed eddy current testing
Profile radiography and pulsed eddy current testing can measure wall thickness through insulation without removal, detecting CUI efficiently.
What is the difference between general and localized corrosion?
Answer: General affects uniform areas while localized concentrates in specific spots
General corrosion causes relatively uniform thickness loss over large areas, while localized corrosion concentrates in specific spots creating deeper damage.
How are corrosion coupons used in pressure vessel monitoring?
Answer: As sacrificial samples installed inside the vessel to measure actual corrosion rates
Corrosion coupons are small metal samples installed inside vessels that are periodically removed and measured to determine actual corrosion rates.