API API-571 Online Practice Questions and Exam Preparation

API API-571 Online Questions & Answers

• Question 181:

  Formation of a metallurgical phase known as sigma phase results in a loss of _________ in some stainless steels as a result of high temperature exposure.

  A. Ductility
  B. Fracture toughness
  C. Embrittlement
  D. None of the above
  B. Fracture toughness

• Question 182:

  Foul smelling water may be a sign of fouling and/or _______

  A. MIC
  B. HIC
  C. SOHIC
  D. All of the above
  A. MIC

• Question 183:

  MIC is often found in _________, bottom water of storage tanks, piping with stagnant or low flow and piping in contact with some soils.

  A. Vessels
  B. Heat exchangers
  C. Drums
  D. All of the above
  B. Heat exchangers

• Question 184:

  Caustic stress corrosion cracking can be effectively prevented by:

  A. The use of 300 series stainless steels
  B. The use of a stress-relieving treatment
  C. Limiting caustic concentration to less than 100 ppm
  D. Limiting metal temperatures to less than 150 癋 (65 癈)
  B. The use of a stress-relieving treatment

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  Comprehensive and Detailed From Exact Extract:

  Caustic stress corrosion cracking (Caustic SCC) occurs when carbon and low-alloy steels are exposed to caustic environments in the presence of tensile stress.

  Per API RP 571, the most effective and proven prevention method is postweld stress-relief heat

  treatment, which:

  Reduces residual welding stresses

  Eliminates one leg of the SCC triangle (stress)

  Why other options are incorrect: 300 series stainless steels are also susceptible under some caustic conditions. SCC can occur even at low caustic concentrations. SCC has been observed below 150 癋 in high-stress areas.

  Referenced Documents (Study Basis):

  API RP 571 - Section on Caustic Stress Corrosion Cracking

• Question 185:

  Internal galvanic corrosion in piping near the joint of two dissimilar metals is best detected by external:

  A. Liquid-penetrant testing
  B. Metallographic examination
  C. Eddy-current testing
  D. Ultrasonic thickness testing
  D. Ultrasonic thickness testing

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  API RP 571 states under Galvanic Corrosion:

  "Because galvanic corrosion usually manifests as, thinning of the more anodic metal ultrasonic thickness measurements taken near dissimilar metal joints are an effective way to detect this type of internal corrosion."

  "Surface NDE techniques like liquid penetrant or magnetic particle testing are not effective for detecting wall loss."

  Thus, option D (ultrasonic thickness testing) is correct.

• Question 186:

  Dissimilar weld metal cracking can be aggravated by _______.

  A. Stress
  B. Pressure
  C. Thermal cycling
  D. Cyclic stresses
  C. Thermal cycling

• Question 187:

  Besides corrosion, what other damage mechanism in hydrofluoric (HF) acid service should inspectors be alert to?

  A. Hydrogen stress cracking
  B. Fluoride stress cracking
  C. Stress corrosion cracking
  D. Wet HF cracking
  A. Hydrogen stress cracking

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  API RP 571 -Hydrogen Stress Cracking - HF Acid Service :

  "HF acid environments can cause hydrogen stress cracking (HSC) in carbon steel, particularly in areas with

  high hardness or residual stress."

  "This is distinct from general corrosion and requires specific inspection focus."

  So, option A is correct.

• Question 188:

  Dew point corrosion can occur if the metal temperature is below the dew point. The dew point of sulfuric acid is __________.

  A. 280?F
  B. 220?F
  C. 310?F
  D. 190?F
  A. 280?F

• Question 189:

  Corrosion of carbon steel and other alloys from their reaction with sulfur compounds in high temperature environments is called ______. The presence of hydrogen accelerates corrosion.

  A. Sulfide corrosion
  B. High temperature corrosion
  C. H睸 corrosion
  D. Sulfidation
  D. Sulfidation

• Question 190:

  During inspection of a process unit where sulfidation from high-temperature hydrogen exists in H#S streams, the inspector should:

  A. Use ultrasonic testing or radiographic testing thickness readings to monitor for loss of wall thickness
  B. Use penetrant testing and magnetic-particle testing to look for surface-breaking cracks
  C. Use angle beam ultrasonic testing to look for cracking at the mid-wall
  D. Take boat samples and send them to the lab for metallographic analysis
  A. Use ultrasonic testing or radiographic testing thickness readings to monitor for loss of wall thickness

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  API RP 571 under Sulfidation (High Temperature Sulfidic Corrosion) recommends:

  "Thickness monitoring using ultrasonic testing (UT) or radiographic testing (RT) is the most common method

  for detection of wall loss due to sulfidation."

  "Sulfidation results in uniform thinning, especially in low Cr steels in hydrogen/H#S environments."

  API RP 571, Section 4.2.1.1 - Sulfidation)

  Thus, option A is the most appropriate and effective inspection method.