API API-571 Online Practice Questions and Exam Preparation

API API-571 Online Questions & Answers

• Question 351:

  The removal of surface material by impacting materials is called:

  A. Erosion
  B. Erosion corrosion
  C. Erosion or erosion corrosion
  D. IPC (imparting particle corrosion)
  A. Erosion

• Question 352:

  The primary cause of ammonium chloride corrosion is the formation of salts:

  A. That may precipitate from high-temperature streams as they are cooled
  B. During water washing operations in streams containing traces of chlorides
  C. That may deposit when water evaporates to dry-out conditions as streams are heated
  D. When steam is injected into streams containing traces of chlorides
  A. That may precipitate from high-temperature streams as they are cooled

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  API RP 571 under Ammonium Chloride Corrosion details:

  "The corrosion results from the deposition of ammonium chloride salts from high-temperature process streams as they cool." "This typically occurs in crude unit overheads or other systems where salts condense out as the stream temperature drops below their dew point." "Corrosion becomes especially aggressive when the salts are wetted by condensation."

  API RP 571, Section 4.3.3.1 - Ammonium Chloride Corrosion)

  Therefore, option A is technically accurate and supported.

• Question 353:

  At which of the following temperatures would the highest atmospheric corrosion rates be expected?

  A. 175癋 (79癈)
  B. 200癋 (93癈)
  C. 250癋 (120癈)
  D. 275癋 (135癈)
  A. 175癋 (79癈)

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  API RP 571 under Atmospheric Corrosion notes:

  "The highest corrosion rates are typically observed between 80癋 and 120癋 (27癈-49癈), particularly when relative humidity is high and surfaces are wet from condensation or rain." "At higher temperatures, surface dryness generally reduces corrosion activity despite increased reaction kinetics."

  API RP 571, Section 4.3.1.3 - Atmospheric Corrosion)

  Thus, among the listed temperatures, 175癋 is closest to the upper end of the most active corrosion window, making option A the most accurate answer.

• Question 354:

  Which of the following metals is the most anodic?

  A. Zinc
  B. Carbon Steel
  C. Nickel
  D. Monel
  A. Zinc

• Question 355:

  Typical HF Alkylation units operate with 1% to 3% water in the acid, equivalent to an HF-in- water concentration of 97% to 99% and the temperatures are generally below _________.

  A. 300?F
  B. 250?F
  C. 200?F
  D. 150?F
  D. 150?F

• Question 356:

  The type of organic acids in crude feedstocks that are of most concern for corrosion in crude unit overheads are those:

  A. With naphthenic acids
  B. With low molecular weight
  D. That are not soluble in naphtha
  E. That condense above the water dew point
  D. That are not soluble in naphtha

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  API RP 571, under Organic Acid Corrosion, highlights:

  "Corrosive organic acids in overhead systems are those that condense at temperatures above the water dew

  point. These acids condense independently of water and can form highly concentrated corrosive films."

  "When acids condense first, they aggressively corrode carbon steel prior to any water wash mitigation."

  API RP 571, Section 4.3.3.9 - Organic Acid Corrosion)

  Hence, option D correctly identifies the most aggressive corrosion scenario.

• Question 357:

  300 Series SS, 400 Series SS and duplex SS are subject to pitting and localized corrosion under insulation. In addition, __________ are also subject to SCC if chlorides are present, while _________ are less susceptible.

  A. Duplex SS, Low alloys
  B. 300 Series SS, Duplex SS
  C. Duplex SS, 300 Series Ss
  D. None of the above
  B. 300 Series SS, Duplex SS

• Question 358:

  Sigma phase occurs in Ferritic, martensitic, austenitic and duplex stainless steels when exposed to temperatures in the range of _____.

  A. 537?C ?954?C
  B. 621?C ?926?C
  C. 676?C ?760?C
  D. 584?C ?840?C
  A. 537?C ?954?C

• Question 359:

  A loss in ductility of high strength steels due to the penetration of atomic hydrogen can lead to brittle cracking called hydrogen embrittlement. Which of the following materials is susceptible to HE.

  A. Carbon steel
  B. 400 Series SS
  C. Low alloy steel
  D. All of the above
  D. All of the above

• Question 360:

  Once cracking from LME has occurred, grinding out the affected area ______ an acceptable fix.

  A. Is
  B. Is not
  C. Can be
  D. Can not be
  B. Is not