API API-571 Online Practice Questions and Exam Preparation

API API-571 Online Questions & Answers

• Question 511:

  Cracks associated with brittle fracture will typically be _________.

  A. Jagged
  B. Branching
  C. Straight
  D. Perpendicular
  C. Straight

• Question 512:

  Temper embrittlement is a metallurgical change that is not readily apparent and can be confirmed through ________.

  A. Metallographic examination
  B. Impact testing
  C. Metallography
  D. None of the above
  B. Impact testing

• Question 513:

  (Which of the following may be more susceptible to polythionic acid stress corrosion cracking?)

  A. SA-516 Grade 70 carbon steel
  B. Type 304 stainless steel
  C. Monel 400
  D. Type 321 stainless steel
  B. Type 304 stainless steel

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  Comprehensive and Detailed From Exact Extract: Polythionic acid stress corrosion cracking (PASCC) occurs in austenitic stainless steels exposed to sulfur-containing environments during shutdowns, particularly when sulfide scales react with oxygen and moisture. According to API RP 571: Unstabilized stainless steels, such as Type 304, are most susceptible Stabilized grades (e.g., Type 321, titanium-stabilized) are more resistant Carbon steel and Monel are not susceptible to PASCC

  Referenced Documents (Study Basis): API RP 571 - Section on Polythionic Acid SCC

• Question 514:

  What is the best way to inspect for brittle fracture?

  A. Wet fluorescent magnetic-particle testing
  B. Tensile testing
  C. Ultrasonic examination
  D. There is no effective way
  A. Wet fluorescent magnetic-particle testing

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  API RP 571 notes that for detecting existing cracks or flaws that may lead to brittle fracture, especially those that initiate at welds or surface stress points:

  "Wet fluorescent magnetic-particle inspection is highly effective for detecting surface-breaking flaws in

  ferromagnetic materials that are susceptible to brittle fracture."

  "It is sensitive to tight cracks and surface discontinuities that may serve as initiation sites for brittle fracture."

  API RP 571, Section 4.2.1.2 - Brittle Fracture)

  Therefore, option A is correct as it is the most effective NDE technique for detecting early signs of brittle cracking.

• Question 515:

  The level of creep damage is a function of the material and the coincident _________ level at which the creep deformation occurs.

  A. Pressure/Temperature
  B. Pressure/Stress
  C. Temperature/Stress
  D. None of the above
  C. Temperature/Stress

• Question 516:

  (An equipment component made of 1-1/4 Cr-1/2 Mo steel that has lost ductility due to temper embrittlement would be susceptible to further damage by which of the following mechanisms?)

  A. Ductile rupture
  B. 885 癋 (475 癈) embrittlement
  C. Thermal shock
  D. Graphitization
  C. Thermal shock

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  Comprehensive and Detailed From Exact Extract:

  According to API RP 571, temper embrittlement is a metallurgical condition that affects Cr-Mo low-alloy steels, including 1-1/4 Cr-1/2 Mo, when exposed to temperatures typically in the range of 650 癋 to 1100 癋 (345 癈 to 595 癈) over extended periods. This damage mechanism results in a significant loss of fracture toughness and ductility, particularly at lower temperatures. API RP 939-C further explains that temper embrittlement does not significantly reduce tensile strength, but it raises the ductile-to-brittle

  transition temperature (DBTT). As a result, equipment that appears structurally sound may fail catastrophically under sudden loading conditions.

  Once ductility is reduced, the material becomes especially vulnerable to rapid temperature changes, which induce .

  high thermal stresses Thermal shock is therefore a critical secondary damage mechanism. Sudden quenching, cold feed introduction, startup, shutdown, or uneven heating can cause cracking because the embrittled material can no longer accommodate strain plastically.

  Option A (Ductile rupture) is incorrect because temper embrittlement promotes brittle fracture, not ductile failure.

  Option B (885 癋 embrittlement) is incorrect because 885 癋 (475 癈) embrittlement primarily affects carbon steels and some stainless steels, not Cr-Mo steels.

  Option D (Graphitization) occurs at prolonged exposure above approximately 800 癋 (425 癈) in carbon steels and is not the dominant concern for 1-1/4 Cr-1/2 Mo steel in this context.

  API RP 571 explicitly emphasizes that embrittled Cr-Mo steels are highly susceptible to cracking during thermal transients, making thermal shock the most likely and dangerous subsequent damage mechanism.

  Referenced Documents (Study Basis):

  API RP 571 - Section on Temper Embrittlement of Low-Alloy Steels

  API RP 939-C - Metallurgical Effects and Service Risks of Temper Embrittlement

• Question 517:

  Hardness levels above ________ are highly susceptible to hydrogen stress cracking (HF).Time-to-failure decreases as the hardness increases.

  A. 225 BHN
  B. 237 BHN
  C. 241 BHN
  D. 247 BHN
  B. 237 BHN

• Question 518:

  Hydrogen permeation or diffusion rates have been found to be minimal at pH _______ and increase at both higher and lower pH's.

  A. 4
  B. 5
  C. 6
  D. 7
  D. 7

• Question 519:

  Cooling water corrosion and __________ are closely related and should be considered together.

  A. Stress
  B. Velocity
  C. Fouling
  D. Erosion
  C. Fouling

• Question 520:

  Cooling water corrosion is a concern with water-cooled __________ and cooling towers in all applications across all industries.

  A. Pumps
  B. Vessels
  C. Piping
  D. Exchangers
  D. Exchangers