API API-571 Online Practice Questions and Exam Preparation

API API-571 Online Questions & Answers

• Question 361:

  Prevention of high-temperature hydrogen attack is usually achieved by using:

  A. Alloy steels with chromium and molybdenum added to increase carbide stability
  B. Austenitic stainless steel cladding on carbon steel equipment
  C. High-nickel alloy steels selected in accordance with API RP 941
  D. Carbon-manganese steels with low carbon content
  A. Alloy steels with chromium and molybdenum added to increase carbide stability

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  Comprehensive and Detailed From Exact Extract: High-Temperature Hydrogen Attack (HTHA) is described in API RP 571 and API RP 941 as a damage mechanism where hydrogen reacts with carbides at elevated temperature and pressure, forming methane and causing loss of strength and fissuring. Prevention is primarily achieved by selecting materials with stable carbides that resist hydrogen attack. Chromium and molybdenum alloying elements: Form more stable carbides Reduce susceptibility to

  methane formation Extend safe operating limits Why the other options are incorrect:

  Option B may be used in some services but is not the usual prevention method.

  Option C is incorrect because RP 941 does not recommend high-nickel alloys as the primary solution. Option D low-carbon steels are more susceptible, not resistant.

  API RP 571 clearly identifies Cr-Mo alloy steels as the standard mitigation approach.

  Referenced Documents (Study Basis):

  API RP 571 - Section on High-Temperature Hydrogen Attack

  API RP 941 - Nelson Curves and Material Selection

• Question 362:

  Most brittle failures appear as:

  A. Branched cracking.
  B. Intergranular cracking.
  C. Ductile tears.
  D. Cleveage.
  D. Cleveage.

• Question 363:

  Erosion-corrosion is a description for the damage that occurs when corrosion contributes to erosion by removing protective films or scales, or by exposing the metal surface to further ________ under the combined action of corrosion-erosion.

  A. Stress
  B. Corrosion
  C. Oxidation
  D. None of the above
  B. Corrosion

• Question 364:

  Which of the methods are effective for finding thermal fatigue cracks?

  A. MT
  B. PT
  C. VT
  D. All of the above
  D. All of the above

• Question 365:

  In order to minimize and prevent amine SCC, PWHT all carbon steel welds in accordance with API RP _____.

  A. 751
  B. 912
  C. 510
  D. 945
  D. 945

• Question 366:

  A nickel-based buttering layer is often used when welding austenitic stainless steels to carbon steels to avoid dissimilar weld metal cracking because:

  A. Austenitic stainless steels are susceptible to chloride cracking.
  B. Nickel base alloys are much softer than austenitic stainless steels.
  C. The coefficient of thermal expansion is better suited to avoid cracking.
  D. You can avoid the need for post weld heat treatment to lower hardness.
  C. The coefficient of thermal expansion is better suited to avoid cracking.

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  In TR 942-B and API RP 582, it is emphasized:

  "Nickel-based buttering is often used as an intermediate layer to reduce thermal stress mismatch during

  welding of ferritic and austenitic materials."

  "Nickel alloys have a coefficient of thermal expansion closer to that of both stainless steels and carbon steels, reducing stress concentrations and mitigating dissimilar weld cracking."

  "This technique also assists in achieving metallurgical compatibility and mitigating solidification cracking."

  Hence, option C is correct as it directly relates to minimizing thermal expansion mismatches.

• Question 367:

  Although cracks may be seen visually, crack detection for caustic stress corrosion cracking is best detected by WFMT, EC, RT and ______.

  A. PT
  B. MT
  C. ACFM
  D. All of the above
  C. ACFM

• Question 368:

  Which of the following alkanolamine systems is the most aggressive in causing amine corrosion?

  A. Monoethanolamine (MEA)
  B. Diglycolamine (DGA)
  C. Diethanolamine (DEA)
  D. Methyldiethanolamine (MDEA)
  A. Monoethanolamine (MEA)

• Question 369:

  Reheat cracking is most frequently observed in _______ grained sections of a heat- affected zone.

  A. Course
  B. Fine
  C. Dense
  D. Treated
  A. Course

• Question 370:

  If wet electrodes or high moisture content flux weld electrodes are used to weld carbon steel, hydrogen can be charged into the steel resulting in _________.

  A. Reduced tensile strength
  B. Loss of ductility
  C. Delayed cracking
  D. All of the above
  C. Delayed cracking