API API-571 Online Practice Questions and Exam Preparation

API API-571 Online Questions & Answers

• Question 381:

  Stainless steel cyclones, piping ductwork and valves in high temperature FCC regeneration service are susceptible areas for _________.

  A. Brittle fracture
  B. Sigma phase
  C. Cavitation
  D. Corrosion fatigue
  B. Sigma phase

• Question 382:

  The likelihood of brittle fracture is best lessened by:

  A. Using thicker construction materials to lower the resulting stress
  B. Using carbon or low-alloy steels
  C. Frequent inspection of the piping or equipment involved
  D. Postweld heat treatment (PWHT)
  D. Postweld heat treatment (PWHT)

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  From API RP 571, brittle fracture prevention measures include:

  "Postweld Heat Treatment (PWHT) reduces residual stresses in the heat affected zone and base metal, thus lowering susceptibility to brittle fracture."

  "PWHT is particularly effective when applied to pressure-containing components fabricated from carbon steel or low-alloy steel that will experience low-temperature service."

  API RP 571, Section 4.2.1.2 - Brittle Fracture)

  Therefore, while other measures may reduce stress or detect flaws, PWHT directly targets one of the root causes: residual stress. Thus, option D is the best prevention method.

• Question 383:

  _________ is most likely found in hard weld and heat-affected zones and in high strength components.

  A. HIC
  B. SSC
  C. SOHIC
  D. Blistering
  B. SSC

• Question 384:

  Which of the following is not a primary factor contributing to erosion-corrosion?

  A. Impact angle (angle that impacting particles strike metal)
  B. Tensile strength of the metal
  C. Velocity of impacting particles
  D. Corrosiveness of the environment
  B. Tensile strength of the metal

• Question 385:

  Which of the following materials is affected by high temperature corrosion?

  A. Carbon steel
  B. 300 Series SS
  C. 400 Series SS
  D. All of the above
  D. All of the above

• Question 386:

  Caustic embrittlement is a form of stress corrosion cracking characterized by surface- initiated cracks that occur in piping and equipment exposed to caustic, primarily adjacent to non-PWHT welds. Which of the following materials is the most resistant to embrittlement?

  A. Carbon steel
  B. Nickel based alloys
  C. Low alloy steels
  D. 400 Series SS
  B. Nickel based alloys

• Question 387:

  Which of these materials are susceptible to brittle fracture?

  A. Carbon steels
  B. Low alloy steels
  C. 400 Series SS
  D. All of the above
  D. All of the above

• Question 388:

  In steam-generating equipment, caustic corrosion is best prevented through:

  A. keeping temperature below the maximum of 250癋 (120癈).
  B. use of 300 series stainless steels.
  C. proper design.
  D. acid injection to balance pH.
  B. use of 300 series stainless steels.

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  From API RP 571 Section 5.3.3.2 (Caustic Corrosion): "Caustic corrosion, also known as caustic gouging, occurs in boiler systems when caustic concentrates in under-deposit areas or due to improper steam drum and boiler water design. Good design and water treatment practices are key preventive measures." Temperature control or acid injection are not practical or effective mitigation techniques. Design considerations--such as proper water flow, material selection, and minimizing deposits--are essential.

  Hence, the correct answer is Option C.

• Question 389:

  Carbonate stress corrosion cracking usually occurs at welds or cold worked areas that __________.

  A. Have been stressed relieved
  B. Have not been stressed relieved
  C. Have high residual stress
  D. Have high-applied stress
  C. Have high residual stress

• Question 390:

  Which of the following is a contributing factor in caustic corrosion?

  A. Iron oxide concentration
  B. Boiler feed water hardness
  C. Heat traced equipment
  D. Alkalinity of superheated steam
  C. Heat traced equipment

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  API RP 571 describes under Caustic Corrosion:

  "One of the significant contributing factors is caustic accumulation in low-flow or stagnant areas,

  especially in heat-traced lines or around steam injection points."

  "Localized heating can concentrate caustic solutions, promoting corrosion even in carbon or stainless steels."

  Thus, option C (heat-traced equipment) is the correct and technically accurate choice.