API 571: 5.1.1.4 Hydrochloric Acid (HCl)
Corrosion Exam Questions and Answers
(Latest Update 2026)
HCI corrosion very aggressive to most common materials of
construction -
correct answer ✅...
What materials exposed to HCI concentrations below 4.5 are
affected? -
correct answer ✅Carbon steel and low alloy steel. Carbon steel
suffers uniform thining, localized corrosion and under deposit
attack
How resistant are 300/400 series SS? -
correct answer ✅Not usefully resistant. 300/400 will suffer pitting.
300 may suffer chloride stress corrosion cracking
What materials are immune to chloride stress corrosion cracking? -
correct answer ✅Carbon steel, low alloy steel and 400 series SS.
What are the three critical factors in HCI corrosion: -
correct answer ✅Temperature, concentration and alloy
composition
Corrosion Exam Questions and Answers
(Latest Update 2026)
HCI corrosion very aggressive to most common materials of
construction -
correct answer ✅...
What materials exposed to HCI concentrations below 4.5 are
affected? -
correct answer ✅Carbon steel and low alloy steel. Carbon steel
suffers uniform thining, localized corrosion and under deposit
attack
How resistant are 300/400 series SS? -
correct answer ✅Not usefully resistant. 300/400 will suffer pitting.
300 may suffer chloride stress corrosion cracking
What materials are immune to chloride stress corrosion cracking? -
correct answer ✅Carbon steel, low alloy steel and 400 series SS.
What are the three critical factors in HCI corrosion: -
correct answer ✅Temperature, concentration and alloy
composition
