Material Evaluation and Selection 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 and Selection flashcards as text
How is the Minimum Design Metal Temperature (MDMT) defined for a pressure vessel?
Answer: The lowest temperature at which the vessel may be subjected to full design pressure
The MDMT is a design parameter stamped on the nameplate that sets the lower bound for pressurized operation, below which material toughness may be insufficient to prevent brittle fracture.
Per ASME Section VIII Division 1 Figure UCS-66, impact testing exemptions for carbon steel are governed by which factors?
Answer: Material thickness and the exemption curve (A through D) for the specific material specification
Figure UCS-66 assigns each carbon steel specification to a curve (A–D) based on inherent toughness, then relates nominal thickness to the minimum temperature at which impact testing is exempt.
What is the minimum Charpy V-notch energy absorption required for weld metal and HAZ per ASME Section VIII Division 1 UG-84?
Answer: 20 ft-lb (27 J) average with 15 ft-lb (20 J) minimum per specimen
ASME VIII-1 UG-84 requires a minimum average of 20 ft-lb for the three-specimen set with no single specimen below 15 ft-lb for weld procedure and material qualification.
When performing a hydrostatic pressure test at temperatures below the vessel's MDMT, what is the primary risk the inspector must address?
Answer: Brittle fracture of the pressure-containing shell or nozzles
Steel tested below its MDMT may have insufficient fracture toughness to resist the stress imposed by the hydrostatic test pressure, leading to brittle fracture.
ASTM A516 Grade 70 is frequently selected for low-temperature pressure vessel applications primarily because it is:
Answer: Produced with killed, fine-grain practice that improves low-temperature toughness
Killed, fine-grain practice refines the grain size and reduces inclusion content, shifting the ductile-to-brittle transition temperature lower compared to non-fine-grain carbon steel plates.
Which of the following does NOT directly influence the required Charpy impact test temperature for a pressure vessel component per ASME Section VIII?
Answer: The color and type of external corrosion protection coating
External coating type and color have no bearing on the material's fracture toughness or the Code's minimum impact test temperature determination.
When a set of Charpy V-notch specimens fails to meet the minimum energy requirement, which action is typically considered first per ASME Section VIII?
Answer: Re-testing with an additional set of specimens from the same heat or weld
ASME Section VIII Division 1 UG-84 permits one additional set of three Charpy specimens if the initial set fails, provided the re-test set meets both average and minimum requirements.