API API-571 Online Practice Questions and Exam Preparation

API API-571 Online Questions & Answers

• Question 371:

  Low creep ductility is __________ severe in high tensile strength materials and welds.

  A. More
  B. Less
  C. Usually
  D. Not
  A. More

• Question 372:

  Higher __________ containing alloys are used for improved resistance to naphthenic acid corrosion.

  A. Chromium
  B. Carbon
  C. Molybdenum
  D. All of the above
  C. Molybdenum

• Question 373:

  Nitriding of steels becomes most severe at temperatures above:

  A. 200癋 (95癈)
  B. 500癋 (260癈)
  C. 600癋 (315癈)
  D. 900癋 (480癈)
  D. 900癋 (480癈)

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  API RP 571 under Nitriding (Section 4.2.16):

  "Nitriding occurs at elevated temperatures and is most severe at temperatures above 900癋 (480癈)."

  "This mechanism is associated with the reaction of ammonia or other nitrogen-containing compounds with the steel surface, leading to brittle nitride formation."

  Therefore, the correct answer is D.

• Question 374:

  The severity of hydrochloric acid corrosion ________ with _________ HCl concentration and increasing temperatures.

  A. Decreases, decreasing
  B. Increases, increasing
  C. Decreases, increasing
  D. Increases, decreasing
  B. Increases, increasing

• Question 375:

  (Amine stress corrosion cracking is found primarily in the:)

  A. Weld fusion line
  B. Weld heat affected zone
  C. Weld metal
  D. Base metal
  B. Weld heat affected zone

  ---

  Comprehensive and Detailed From Exact Extract: According to, environmentally API RP 571 amine stress corrosion cracking (Amine SCC) is a form of assisted cracking that occurs in alkanolamine systems (e.g., MEA, DEA, DGA) used for acid gas treating. The cracking mechanism requires the simultaneous presence of tensile stress, susceptible microstructure, and an amine environment. API RP 571 clearly states that Amine SCC occurs primarily in the weld heat affected zone (HAZ) of carbon and low-alloy steels. The reasons include: The HAZ contains high residual stresses from welding. The microstructure in the HAZ is metallurgically altered, making it more susceptible than base metal. Cracks often initiate adjacent to welds, not in the weld metal itself. Why the other options are incorrect: Option A (Weld fusion line) is not the primary cracking location. Option C (Weld metal) generally has different chemistry and lower susceptibility. Option D (Base metal) typically has lower residual stress and is less prone. API RP 571 specifically identifies the weld HAZ as the dominant cracking location for Amine SCC. Referenced Documents (Study Basis): API RP 571 - Section on Amine Stress Corrosion Cracking API Corrosion and Materials Study Guide

• Question 376:

  The removal of a material's protective scale by impacting materials is called:

  A. Erosion
  B. Erosion-corrosion
  C. Erosion or erosion-corrosion
  D. IPRSC (imparting particle removal of scale corrosion)
  B. Erosion-corrosion

• Question 377:

  The creep threshold temperature for carbon steel is ________.

  A. 315?C
  B. 371?C
  C. 426?C
  D. 538?C
  B. 371?C

• Question 378:

  SCC usually occurs at pH values above two (2). SCC tendency __________ toward the alkaline pH region

  A. Increases
  B. Decreases
  C. Stabilizes
  D. None of the above
  B. Decreases

• Question 379:

  Amine corrosion is primarily caused by:

  A. amine solutions above 250癋 (121癈).
  B. amine concentration.
  C. dissolved acid gases.
  D. alkaline sour water.
  C. dissolved acid gases.

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  From API RP 571 Section 5.1.1.3 (Amine Corrosion): "Amine corrosion is a form of general or localized corrosion caused by the presence of amine solutions used

  to remove acid gases (H#S and CO#)... Corrosion is most severe in areas where acid gas loading is high."

  While temperature and concentration are contributing factors, the primary driver is dissolved acid gases such as CO# and H#S.

  Thus, the correct answer is Option C.

• Question 380:

  NAC may be found in hot hydrocarbon streams downstream of the crude and vacuum units, __________ any hydrogen mix point.

  A. Upstream of
  B. Downstream of
  C. Adjacent to
  D. Around
  A. Upstream of