API API-571 Online Practice Questions and Exam Preparation

API API-571 Online Questions & Answers

• Question 131:

  ____________ is a form of environmental cracking that can initiate on the surface of high strength low alloy steels and carbon steels with highly localized zones of high hardness in the weld metal and HAZ as a result of exposure to aqueous HF acid service.

  A. Sulfide stress cracking
  B. Hydrogen stress cracking
  C. Caustic stress cracking D. Hydrogen induced cracking
  B. Hydrogen stress cracking

• Question 132:

  In a pump, the difference between the actual pressure, or head, of a liquid available (measured on the suction side) and the vapor pressure of that liquid is called Net Positive Suction Head (NPSH) available. The minimum head required to prevent cavitation with a given liquid at a given flow rate is called Net Positive Suction Head __________. Inadequate NPSH can result in cavitation.

  A. Surplus
  B. Required
  C. Reserve
  D. None of the above
  B. Required

• Question 133:

  For galvanic corrosion to take place, three conditions must be met, presence of an electrolyte, two different materials or alloys and ___________.

  A. A cathode
  B. An anode
  C. An electrical connection
  D. None of the above
  C. An electrical connection

• Question 134:

  An inspector observes sharp-edged pitting in piping immediately downstream from an orifice. This damage has most likely resulted from which damage mechanism?

  A. Flashing
  B. Turbulence
  C. Erosion
  D. Cavitation
  C. Erosion

  ---

  According to API RP 571 Section 5.4.2 (Erosion and Erosion/Corrosion): "Erosion can occur downstream of flow disturbances such as control valves, orifice plates, elbows... It is characterized by localized metal loss with a directional pattern such as grooves or sharp-edged pits in areas of high velocity or turbulence."

  Cavitation and flashing cause damage with different signatures like pitting and spongy surface texture, while

  sharp-edged pitting strongly indicates erosion, especially downstream of flow restriction devices.

  Thus, the correct answer is Option C (Erosion).

• Question 135:

  __________ is a form of cracking that results when certain molten metals come in contact with specific alloys. Cracking can be very sudden and brittle in nature.

  A. SCC
  B. LME
  C. AET
  D. SOHIC
  B. LME

• Question 136:

  Cl SCC usually occurs at metal temperatures above ________.

  A. 125?F
  B. 175?F
  C. 140?F
  D. 200?F
  C. 140?F

• Question 137:

  To prevent hydrogen embrittlement, use lower strength steels and _________ to temper the microstructure, improve ductility and reduce residual stresses.

  A. Alloys
  B. Preheat
  C. PWHT
  D. All of the above
  C. PWHT

• Question 138:

  _______ is the primary alloying agent that affects resistance to oxidation.

  A. Chromium
  B. Molybdenum
  C. Silicon
  D. Aluminum
  A. Chromium

• Question 139:

  A 5Cr-1Mo piping system in the hydrogen unit shows significant internal wall loss after 2 years in service due to CO?corrosion. Which material would be best suited to use to install a new pipe system?

  A. Titanium
  B. 9Cr-1Mo
  C. A-106 Gr B
  D. 316 SS
  D. 316 SS

• Question 140:

  The presence of _________ can destabilize the scale and turn it into a nonprotective scale.

  A. H睸
  B. O?
  C. H?
  D. H睴
  D. H睴