Practice Test Geeks(API 510) Certified Pressure Vessel Inspector Practice Test
← All API 510 Flashcard Decks

Corrosion, Welding & Material Defects 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 Corrosion, Welding & Material Defects flashcards as text

  1. Which type of corrosion occurs when two dissimilar metals are in electrical contact in the presence of an electrolyte?

    Answer: Galvanic corrosion

    Galvanic corrosion occurs when two metals with different electrochemical potentials are in contact with each other and an electrolyte, causing the more active (anodic) metal to corrode preferentially.

  2. What is the primary purpose of post-weld heat treatment (PWHT) on pressure vessel welds?

    Answer: To relieve residual stresses and improve toughness

    PWHT is performed primarily to relieve residual stresses induced during welding and to improve notch toughness, which reduces the risk of brittle fracture.

  3. Which NDE method is MOST effective for detecting subsurface cracks in ferromagnetic pressure vessel materials?

    Answer: Magnetic particle testing (MT)

    Magnetic particle testing (MT) can detect both surface and near-subsurface discontinuities in ferromagnetic materials by revealing flux leakage at defect locations.

  4. Under API 510, what term describes corrosion that occurs uniformly over the entire internal surface of a pressure vessel?

    Answer: General corrosion

    General (uniform) corrosion attacks the exposed surface at a relatively uniform rate, making it predictable and easier to manage through corrosion allowance calculations.

  5. A weld discontinuity that is open to the surface and runs parallel to the weld axis is MOST likely a:

    Answer: Longitudinal crack

    A longitudinal crack runs parallel to the weld axis and can occur in the weld metal, heat-affected zone, or base metal, often due to hot cracking or hydrogen-induced cracking.

  6. What is the term for the selective removal of one element from an alloy by corrosion, such as zinc from brass?

    Answer: Dezincification

    Dezincification is a form of dealloying where zinc is selectively leached from brass, leaving a porous, weakened copper-rich structure.

  7. Which welding defect is characterized by a groove melted into the base metal adjacent to the weld toe that is not filled by weld metal?

    Answer: Undercut

    Undercut is a groove or channel burned into the base metal at the weld toe or root that is left unfilled, reducing the cross-sectional thickness of the base metal.