Material Evaluation Flashcards
7 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 7 Material Evaluation flashcards as text
A 316L stainless steel vessel is suspected of sensitization from an improper heat treatment. Which nondestructive test can detect chromium carbide precipitation at grain boundaries?
Answer: Electrochemical potentiokinetic reactivation (EPR) testing
EPR testing is an electrochemical NDE method specifically designed to detect sensitization in austenitic stainless steels by measuring chromium depletion at grain boundaries.
When reviewing material specifications for a vessel repair, an inspector notes the replacement plate is SA-516-70 and the existing vessel shell is SA-285-C. What is the primary concern with this material combination?
Answer: Mismatch in tensile strength affecting weld joint efficiency calculations
SA-516-70 (70 ksi tensile) and SA-285-C (55 ksi tensile) have different strength levels, requiring the engineer to base joint efficiency calculations on the weaker material.
A vessel in amine service develops cracking that is confirmed as amine stress corrosion cracking. Which metallurgical condition of the base metal and welds is the most important risk factor?
Answer: High residual tensile stresses from fabrication combined with hardness above 200 BHN
Amine SCC requires tensile stress to propagate; high residual stresses from cold forming or welding combined with elevated hardness significantly increase susceptibility.
An inspector identifies a section of vessel wall that has experienced creep damage. Which of the following microstructural features confirms advanced creep damage during metallurgical examination?
Answer: Creep voids and microfissures along grain boundaries leading to grain boundary cracking
Advanced creep damage is characterized by creep voids (cavities) forming at grain boundaries that link to form microfissures, ultimately leading to intergranular cracking and failure.
A low-alloy steel (2.25Cr-1Mo) vessel has undergone long-term service at 850°F. The inspector is evaluating the material for temper embrittlement. Which test best quantifies the degree of embrittlement?
Answer: Charpy V-notch impact testing at 32°F vs. baseline impact values
Charpy V-notch impact testing at a reference temperature compared to original baseline values directly measures the shift in DBTT caused by temper embrittlement.
An API 510 inspector must evaluate a vessel with unknown wall thickness measurements that are less than the original nominal thickness minus the corrosion allowance. What is the first step in the fitness-for-service evaluation?
Answer: Calculate the required minimum thickness per the applicable design code at current operating conditions
The first step is calculating the required minimum thickness (t_min) per the original code formulas using current operating pressure and temperature to determine if remaining thickness is adequate.
During material evaluation of a carbon steel vessel, the inspector finds spheroidized carbides throughout the microstructure. What does this indicate about the material's service history and current condition?
Answer: The steel has been exposed to elevated temperatures causing carbide agglomeration, reducing strength and hardness
Spheroidization results from prolonged elevated temperature exposure where lamellar carbides agglomerate into spheres, reducing tensile strength and hardness below original specification.