API 571: 4.5.3 Caustic Stress Corrosion
Cracking (Caustic Embrittlement) Exam
Questions and Answers (Latest Update
2026)
What is caustic embrittlement? -
correct answer ✅It is stress corrosion cracking characterized as
surface-initiated cracks that occurs in piping/equipment that is
exposed to caustic solutions such as sodium/potassium hydroxide.
What materials are suscecptible to caustic embrittlement? -
correct answer ✅carbon steel, low alloy steel and 300 series SS.
Nickel based alloys are more resistant.
What are the three main critical factors for caustic embrittlement? -
correct answer ✅Caustic solutions must be present, such as
sodium/potassium hydroxide. Caustic strength, stress levels and
temperature.
What is the relationship between caustic concentration and
temperature for cracking? -
correct answer ✅Increasing caustic concentration and increasing
temperature increases the likelihood and severity of cracking.
As per the carbon steel in caustic service what information can be
drawn for the table, this table is established through experience... -
, API 571: 4.5.3 Caustic Stress Corrosion
Cracking (Caustic Embrittlement) Exam
Questions and Answers (Latest Update
2026)
correct answer ✅the table represents carbon steel in caustic
service.
The conclusions that can be drawn are:
Up to 100F then no stress relief is necessary.
Raise the temperature from 100-200F then stress relief must be
applied to welds and bends (areas of stress)
From 200-260F: nickel alloys to be considered.
100-260F: nickel alloy trim for valves
Summary: Raise temperature past 100F and stress relieving
necessary for welds and bends. Over 200F then nickel alloys to be
considered.
Cracking can occur at low caustic levels if a concentrating
mechanism is present, what are examples of concentrating
mechanisms and a short summary of each description? -
correct answer ✅DNB (Departure from nucleate boiling): bubbles
form and are normally washed away in normal conditions. In DNB
when the rate of bubble formation exceeds the flow of the rinsing
water, at higher rates a stable film may occur with solid
Cracking (Caustic Embrittlement) Exam
Questions and Answers (Latest Update
2026)
What is caustic embrittlement? -
correct answer ✅It is stress corrosion cracking characterized as
surface-initiated cracks that occurs in piping/equipment that is
exposed to caustic solutions such as sodium/potassium hydroxide.
What materials are suscecptible to caustic embrittlement? -
correct answer ✅carbon steel, low alloy steel and 300 series SS.
Nickel based alloys are more resistant.
What are the three main critical factors for caustic embrittlement? -
correct answer ✅Caustic solutions must be present, such as
sodium/potassium hydroxide. Caustic strength, stress levels and
temperature.
What is the relationship between caustic concentration and
temperature for cracking? -
correct answer ✅Increasing caustic concentration and increasing
temperature increases the likelihood and severity of cracking.
As per the carbon steel in caustic service what information can be
drawn for the table, this table is established through experience... -
, API 571: 4.5.3 Caustic Stress Corrosion
Cracking (Caustic Embrittlement) Exam
Questions and Answers (Latest Update
2026)
correct answer ✅the table represents carbon steel in caustic
service.
The conclusions that can be drawn are:
Up to 100F then no stress relief is necessary.
Raise the temperature from 100-200F then stress relief must be
applied to welds and bends (areas of stress)
From 200-260F: nickel alloys to be considered.
100-260F: nickel alloy trim for valves
Summary: Raise temperature past 100F and stress relieving
necessary for welds and bends. Over 200F then nickel alloys to be
considered.
Cracking can occur at low caustic levels if a concentrating
mechanism is present, what are examples of concentrating
mechanisms and a short summary of each description? -
correct answer ✅DNB (Departure from nucleate boiling): bubbles
form and are normally washed away in normal conditions. In DNB
when the rate of bubble formation exceeds the flow of the rinsing
water, at higher rates a stable film may occur with solid
