API API-571 Online Practice Questions and Exam Preparation

API API-571 Online Questions & Answers

• Question 91:

  Which of the following would be most useful in finding carbolic acid corrosion?

  A. Angle beam ultrasonic testing
  B. Acoustic emission testing
  C. Cutting a boat sample for laboratory analysis
  D. Ultrasonic and radiographic testing
  C. Cutting a boat sample for laboratory analysis

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  Comprehensive and Detailed From Exact Extract: Carbolic acid corrosion (phenol corrosion) is described in API RP 571 as a process-specific corrosion

  mechanism that may not produce distinct or easily detectable wall-loss patterns using conventional NDE

  methods.

  API RP 571 emphasizes that confirmation of carbolic acid corrosion often requires:

  Chemical identification of corrosion products

  Metallurgical examination

  Verification of acid presence and metal interaction

  A boat sample (also known as a coupon or scoop sample) removed from the affected area and analyzed in a laboratory allows: Identification of corrosion morphology Chemical analysis of deposits Confirmation of phenol-related attack

  Why the other options are incorrect: UT and RT detect wall loss but cannot identify the corrosion mechanism. Acoustic emission detects active cracking, not specific corrosion chemistry. Angle beam UT is for crack detection, not corrosion identification.

  Therefore, laboratory analysis of a removed sample is the most useful method.

  Referenced Documents (Study Basis): API RP 571 - Section on Organic Acid Corrosion (Phenols)

  API Corrosion Failure Analysis Study Guide

• Question 92:

  Cooling water corrosion usually increases with decreasing:

  A. Microbiological activity
  B. Oxygen content
  C. Process temperatures
  D. Velocities
  D. Velocities

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  Comprehensive and Detailed From Exact Extract:

  According to API RP 571, corrosion in cooling water systems often increases at low flow velocities due to:

  Stagnation

  Deposit formation

  Increased risk of underdeposit corrosion and MIC Higher velocities tend to: Sweep away deposits Maintain protective films (within erosion limits) Therefore, decreasing velocity is strongly associated with increased corrosion risk. Referenced Documents (Study Basis):

  API RP 571 - Section on Cooling Water Corrosion

• Question 93:

  Sulfidation usually creates:

  A. Uniform corrosion.
  B. Isolated pitting.
  C. Intergranular cracking.
  D. Transgranular cracking.
  E. Hard and brittle zones.
  F. Inspection nightmares.
  A. Uniform corrosion.

• Question 94:

  Primarily hot-wall piping and equipment in the following units can be affected by graphitization. FCC, catalytic reformer and ______.

  A. Hydrotreater
  B. Hydrocracker
  C. Coker
  D. Alky
  C. Coker

• Question 95:

  The rate of creep deformation is a function of the material, load and temperature. The rate of damage is sensitive to both load and temperature. Generally, an increase of about _______ or an increase of ________ on stress can cut the remaining life in half.

  A. 25?F, 15%
  B. 50?F, 10%
  C. 50?F, 15%
  D. 25?F, 10%
  A. 25?F, 15%

• Question 96:

  The 300 series stainless steels (austenitic stainless steels) are generally resistant to oxidation up to what temperature?

  A. 1300癋 (704癈)
  B. 1400癋 (760癈)
  C. 1500癋 (815癈)
  D. 1600癋 (871癈)
  C. 1500癋 (815癈)

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  According to API RP 571, under Oxidation:

  "Austenitic stainless steels (300 Series) are generally used for oxidation resistance up to about 1500癋 (815?

  C). At higher temperatures, scaling and loss of protective chromium oxide layers increase."

  "Above these temperatures, specialized high-temperature alloys may be required."

  API RP 571, Section 5.1.1 - Oxidation)

  Therefore, option C is the correct answer.

• Question 97:

  (Which of the following damage mechanisms affects most common materials of construction?)

  A. Sour water corrosion
  B. Microbiologically induced corrosion
  C. Polythionic acid corrosion
  D. Amine corrosion
  B. Microbiologically induced corrosion

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  Comprehensive and Detailed From Exact Extract: Microbiologically Induced Corrosion (MIC) is one of the most universally applicable corrosion mechanisms, affecting: Carbon steel Low-alloy steel Stainless steels Copper alloys Aluminum alloys According to API RP 571, MIC can occur in any aqueous system where microorganisms are present, regardless of metallurgy. By contrast: Sour water corrosion and amine corrosion mainly affect carbon steel Polythionic acid corrosion is limited to austenitic stainless steels Referenced Documents (Study Basis): API RP 571 - Section on Microbiologically Induced Corrosion

• Question 98:

  ________ usually occurs when a colder liquid contacts a warmer metal surface.

  A. Stress cracking
  B. Thermal fatigue
  C. Thermal shock
  D. Stress shock
  C. Thermal shock

• Question 99:

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

  A. Impact angle (angle that impacting particles strike metal)
  B. Size of impacting particles
  C. Velocity of impacting particles
  D. Density of impacting particles
  E. Corrosiveness of the environment
  E. Corrosiveness of the environment

• Question 100:

  Which of the following is the best description of the surface appearance of metals with chloride stress corrosion cracking?

  A. Concentric ring "beach mark" cracking
  B. Linear cracking along weld heat-affected zones
  C. Highly branched crazed cracking
  D. Linear cracking with few branches extending away from welds
  C. Highly branched crazed cracking

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  API RP 571, under Chloride Stress Corrosion Cracking, notes:

  "Cracking often appears as highly branched or `crazed' networks on the surface, especially in austenitic

  stainless steels exposed to chlorides under tensile stress."

  "These cracks often initiate in the heat-affected zones or cold-worked areas and are intergranular in nature."

  This signature `crazed' appearance with branching is diagnostic of Cl-SCC, making option C the correct and most descriptive answer.