API 571 Study Guide 2026
Everything you need to pass the API 571 exam in one place: the exam format, every topic to study, real practice questions with explanations, flashcards, and full-length practice tests. Free, no sign-up needed.
📋 API 571 Exam Format at a Glance
📚 API 571 Topics to Study (21)
✍️ Sample API 571 Questions & Answers
1. How does overload fracture differ from fatigue fracture in terms of fracture surface appearance?
Overload fracture occurs in a single loading event, producing ductile (dimpled) or brittle (cleavage) features but never the progressive beach marks seen in fatigue.
2. Which alloy provides the best resistance to naphthenic acid corrosion in high-temperature crude service?
Molybdenum-containing stainless steels such as 316L exhibit significantly better naphthenic acid resistance than carbon or low-alloy steels.
3. What operational change most effectively reduces the risk of HTHA in process equipment?
Operating below the applicable Nelson curve limit, by reducing temperature and/or hydrogen partial pressure, is the primary strategy for HTHA prevention.
4. Which temperature range is considered the primary zone of concern for Corrosion Under Insulation (CUI) on carbon steel equipment per API 583?
API 583 identifies 25°F to 250°F (–4°C to 121°C) as the primary CUI temperature range for carbon steel, where liquid water can be present and trapped beneath insulation to drive corrosion.
5. Which damage mechanism converts metal into a powder of metal particles, oxides, and carbon through a catastrophic carburization reaction?
Metal dusting is a catastrophic form of carburization in which steel disintegrates into a dust of metal, oxides, and carbon due to supersaturated carbon activity in the gas.
6. The Couper-Gorman curves extend McConomy curves by accounting for what additional factor?
Couper-Gorman curves account for the accelerating effect of hydrogen partial pressure on H2S corrosion rates in hydrogen-containing environments.