API API-571 Online Practice Questions and Exam Preparation

API API-571 Online Questions & Answers

• Question 551:

  Atmospheric corrosion:

  A. Can cause either uniform or localized wall loss.
  B. Always causes localized wall loss.
  C. Always causes uniform wall loss.
  D. Is best detected using profile RT.
  A. Can cause either uniform or localized wall loss.

• Question 552:

  (Which damage mechanism occurs primarily as a result of exposure of interior vessel surfaces to air and moisture conditions during shutdown?)

  A. Polythionic acid stress corrosion cracking
  B. Wet hydrogen sulfide cracking
  C. Carbonate stress corrosion cracking
  D. Sour water stress corrosion cracking
  A. Polythionic acid stress corrosion cracking

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  Comprehensive and Detailed From Exact Extract:

  Polythionic acid stress corrosion cracking (PASCC) occurs when sulfide scales on stainless steel surfaces

  are exposed to oxygen and moisture, most commonly during shutdowns and outages.

  Per API RP 571:

  Polythionic acids form when iron sulfides react with air and water Cracking occurs in austenitic stainless steels Damage is most likely during shutdown, not normal operation Therefore, PASCC is the damage mechanism directly associated with shutdown exposure conditions.

  Referenced Documents (Study Basis): API RP 571 - Section on Polythionic Acid Stress Corrosion Cracking

• Question 553:

  Heat treatment can have a significant effect on the toughness and hence fatigue resistance of a metal. In general, ________ grained microstructures tend to perform better than _________ grained.

  A. Fine, Course
  B. Austenetic, martensitic
  C. Course, Fine
  D. Martensitic, austenetic
  A. Fine, Course

• Question 554:

  Hydrogen stress cracking is the same mechanism that is responsible for sulfide stress corrosion cracking in wet H睸 environments except that HF acid is generating the __________.

  A. Sulfide
  B. Caustic
  C. Hydrogen
  D. Water
  C. Hydrogen

• Question 555:

  Which of the following materials are the least susceptible to caustic embrittlement?

  A. Carbon steel
  B. Stainless steel
  C. 9Cr-0.5 Mo
  D. Nickel base alloys
  D. Nickel base alloys

• Question 556:

  With very few exceptions, cooling water should always be on the ________ side to minimize stagnant areas.

  A. Tube
  B. Shell
  C. Inlet
  D. Outlet
  A. Tube

• Question 557:

  A form of corrosion caused by living organisms such as bacteria, algae or fungi is _______ .

  A. HIC
  B. SOHIC
  C. MIC
  D. None of the above
  C. MIC

• Question 558:

  _________ is a selective corrosion mechanism in which one or more constituents of an alloy are preferentially attacked leaving a lower density often porous structure.

  A. Phenol corrosion
  B. Dealloying
  C. Carburization
  D. Preferentially weld attack
  B. Dealloying

• Question 559:

  The grain size has an important influence on the high temperature ductility and on the reheat cracking susceptibility. A ________ grain size results in _______ ductile heat affected zones, making the material more susceptible to reheat cracking.

  A. Large, more
  B. Small. Less
  C. Large, Less
  D. Small, More
  C. Large, Less

• Question 560:

  Carbonate stress corrosion cracking is the term applied to surface breaking or cracks that occur adjacent to carbon steel welds under the combined action of ____________ and ___________ in carbonate containing systems.

  A. Temperature, stress
  B. Tensile stress, corrosion
  C. Corrosion, velocity
  D. Tensile stress, velocity
  B. Tensile stress, corrosion