Caustic Stress Corrosion Cracking Flashcards
- Caustic Stress Corrosion Cracking can cause cracks that normally initiate:
A. On the surface adjacent to welds
B. At the mid-wall adjacent to welds
C. On the surface in the base metal
D. At the mid-wall in the base metal
A. On the surface adjacent to welds
- Which alloys are more resistant to Caustic Stress Corrosion Cracking?
A. Chromes
B. Ferrites
C. Nickels
D. Sulfides
B. Ferrites
- Which of the following is NOT a factor in the Caustic Stress Corrosion Cracking?
A. Material
B. Stress
C. Temperature
D. Time
D. Time
- If a “concentrating mechanism” is present, Caustic Stress Corrosion Cracking can occur when the caustic concentration is as low as? (Open Book)
A. 50-100 ppm
B. 100-200 ppm
C. 250-500 ppm
D. 1000-2000 ppm
A. 50-100 ppm
- The likelihood of Caustic Stress Corrosion Cracking can be reduced by:
A. Increasing the operational temperature
B. reducing the fluid velocity
C. stress-relieving
D. using low-hydrogen electrodes
C. stress-relieving
- In carbon steel equipment, a high concentration of caustic at a high temperature:
A. Can cause transgranular cracking
B. Can cause through-wall cracking in a matter of hours
C. Will cause cracks to initiate on inside of pipe ells
D. Will cause cracks to initiate in crevices
B. Can cause through-wall cracking in a matter of hours
- In which of the following situations can Caustic be Concentrated? This may have more than one correct answer, please select all answers that apply.
A. Alternating wet and dry conditions
B. Localized hots pots
C. Chloride injection points
D. High-temperature steam-out
A. Alternating wet and dry conditions
B. Localized hots pots
D. High-temperature steam-out
- In caustic equipment, which of the following can contribute to Caustic Stress Corrosion Cracking, if improperly designed?
A. Flanges
B. Nozzles
C. Reducers
D. Heat Tracing
D. Heat Tracing
- Which of the following is a common way that operations causes Caustic Stress Corrosion Cracking in caustic equipment?
A. Increasing flow rate
B. lowering the pH
C. overpressure
D. steam cleaning
D. steam cleaning
- Which common plant process has traces of Caustic that might “concentrate” in some situations?
A. boiler feed water
B. cooling water
C. hydrogen
D. plant air
E. plant nitrogen
A. boiler feed water
- Caustic Stress Corrosion Cracking in carbon steel normally appears as a:
A. Crack initiating on the outside surface
B. Large wide crack
C. Spider web of small cracks
D. Transgranular crack
C. Spider web of small cracks
- In order to minimize the potential for Caustic SCC in carbon steel equipment, a post-weld-heat-treatment of 1150F should be held for a minimum of: (Open book)
A. 15 minutes
B. 1 hour
C. 1 hour per every inch of thickness
D. 2 hours
B. 1 hour
- During a unit outage, a caustic pipe system needs cleaned prior to opening. A steam-out is preferred by Operations. Which of the following should be done? * This may have more than one correct answer, please select all answers that apply
A. Prior to steam-out, wash out equipment with light oil
B. Prior to steam-out, wash out equipment with water
C. Use only low-pressure steam for short periods of time
D. Use steam at a pressure of ≥300 psig
E. Prior to steam-out, wash line with strong acid
D. Inspect all welds prior to steam-out
B. Prior to steam-out, wash out equipment with water
C. Use only low-pressure steam for short periods of time
- Which of the following NDE techniques can be effective in detecting surface breaking Caustic Stress Corrosion cracks?* This may have more than one correct answer, please select all answers that apply
A. ACFM
B. ECT
C. PT
D. RT
E. UT straight-beam
F. WFMPT
A. ACFM
B. ECT
F. WFMPT
- Which of the following NDE techniques can be effective in detecting and sizing Caustic Stress Corrosion cracks?* This may have more than one correct answer, please select all answers that apply
A. ECT
B. RT
C. UT angle-beam
D. UT straight-beam
E. WFMPT
C. UT angle-beam
