API API-571 Online Practice Questions and Exam Preparation

API API-571 Online Questions & Answers

• Question 221:

  _________ corrosion rates are found in a gas oil desulfurizers and hydrocrackers than naphtha desulfurizers and hydrocrackers by a factor of almost "2".

  A. Lower
  B. Higher
  C. Sulfidization
  D. Hydrogen corrosion
  B. Higher

• Question 222:

  _________ is the result of cyclic stress caused by variations in temperature.

  A. Creep
  B. Thermal Fatigue
  C. Cyclic Cracking
  D. Stress Corrosion Cracking
  B. Thermal Fatigue

• Question 223:

  ________ of a component is the most important factor in determining a components resistance to mechanical fatigue.

  A. Design
  B. Temperature
  C. Stress
  D. Pressure
  A. Design

• Question 224:

  Amine corrosion depends on the design, operating practices, the type of amine, amine concentration, temperature and _________.

  A. Pressure
  B. Velocity
  C. Stress
  D. None of the above
  B. Velocity

• Question 225:

  High temperature hydrogen attack results from exposure to hydrogen at elevated temperatures and pressures. The hydrogen reacts with __________ in steel to produce _________, which cannot diffuse through the steel. The loss of carbides causes an overall loss in strength.

  A. Carbides, oxygen
  B. Alloys, hydrogen dioxide
  C. Carbides, methane
  D. Hydrogen dioxide, H睸
  C. Carbides, methane

• Question 226:

  Oxidation of carbon steel begins to become significant above _________.

  A. 800?F
  B. 900?F
  C. 1000?F
  D. 1100?F
  C. 1000?F

• Question 227:

  Spheroidization is a change in the microstructure of steels that can occur after exposure to a minimum temperature of:

  A. 650癋 (345癈)
  B. 700癋 (370癈)
  C. 850癋 (455癈)
  D. 1000癋 (540癈)
  A. 650癋 (345癈)

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  According to API RP 571 Section 5.3.2.3 (Spheroidization):

  "Spheroidization is a microstructural degradation that occurs in carbon steels and low alloy steels when exposed to elevated temperatures for long periods, typically beginning at temperatures as low as 650癋 (345?C). It involves the transformation of lamellar pearlite into spherical cementite particles, reducing strength and hardness." Thus, Option A (650癋 / 345癈) is the minimum threshold temperature for spheroidization to begin.

• Question 228:

  Which of the following can increase the corrosion rate of carbon steel via hydrofluoric (HF) acid corrosion?

  A. High nitrogen content in process
  B. Oxygen contamination
  C. HF acid concentration above 98%
  D. Weld hardness above 200 BHN
  D. Weld hardness above 200 BHN

  ---

  According to API RP 571 and API RP 751:

  "In HF alkylation units, carbon steel can be used if weld hardness is controlled to # 200 Brinell (BHN).

  Exceeding this can significantly increase the corrosion rate and susceptibility to cracking."

  "Hard welds act as preferential corrosion sites due to microstructural inhomogeneity and stress concentration."

  API RP 571, Section 4.3.3.4 - Hydrofluoric Acid Corrosion; API RP 751, Section 5.3 - Materials of Construction) Thus, option D is correct.

• Question 229:

  Blistering, HIC and SOHIC have been found to occur between ambient and ________.

  A. 250?F
  B. 300?F
  C. 350?F
  D. 400?F
  B. 300?F

• Question 230:

  _________ is a change in the microstructure of certain carbon steels and 0.5Mo steels after long-term operation in the 800?F to 1100?F range that may cause a loss in strength, ductility and/or creep resistance.

  A. Embrittlement
  B. Carburization
  C. Graphitization
  D. Sensitization
  C. Graphitization