What is the API-571 certification exam?

API-571 is a professional certification exam focused on corrosion and materials knowledge for the oil and gas industry. It validates an individual's expertise in identifying, preventing, and managing corrosion in industrial equipment and piping systems.

Who should take the API-571 exam?

The API-571 exam is ideal for engineers, inspectors, maintenance professionals, and operations personnel working in refining, petrochemical, and pipeline industries. It is particularly valuable for those involved in asset integrity management and corrosion control programs.

What are the main topics covered in API-571?

The exam covers corrosion mechanisms, materials selection, corrosion control methods, inspection techniques, and failure analysis. Key areas include high-temperature corrosion, erosion-corrosion, stress corrosion cracking, and underground corrosion.

How do I prepare for the API-571 certification exam?

Candidates should study the official API-571 standard document thoroughly and consider taking preparatory courses offered by API or authorized training providers. Practice exams and study groups can also help reinforce understanding of corrosion mechanisms and material properties.

What is the passing score and exam format for API-571?

The API-571 exam typically consists of multiple-choice questions and requires a passing score of around 70% to 75%, though specific requirements may vary. The exam is usually offered in a proctored format either in-person or online through approved testing centers.

Free API-571 Exam Questions

Q1 MultipleChoice

Which of the following statements about high-temperature hydrogen attack is most accurate?

AAcoustic emission testing is not a proven method for the detection of high-temperature hydrogen attack damage.

BHigh-temperature hydrogen attack will most often be associated with the formation of surface blisters.

CHigh-temperature hydrogen attack damage is most often limited to welds and heat-affected zones.

D300 series stainless steels are also susceptible to high-temperature hydrogen attack at conditions normally seen in refinery units.

Correct Answer: A

Explanation:

API RP 571 on HTHA states:

''Acoustic emission testing is not currently a proven or reliable method for identifying HTHA in refinery components.''

''HTHA typically occurs internally, not as surface blisters, and is not limited to welds. Austenitic (300 series) stainless steels are generally resistant at normal refinery conditions.''

(Reference: API RP 571, Section 4.2.1.3 -- High Temperature Hydrogen Attack)

Thus, option A is the most accurate statement.

Q2 MultipleChoice

What alloy element most improves naphthenic acid corrosion (NAC) resistance?

AMolybdenum

BChromium

CNiobium

DNickel

Correct Answer: A

Explanation:

API RP 571, Naphthenic Acid Corrosion:

''Molybdenum significantly improves resistance to naphthenic acid attack. Alloys such as 317, 316Mo, and Alloy 20 are used in severe NAC environments due to higher Mo content.''

''Chromium and nickel play secondary roles; molybdenum is the key element.''

Answer is A -- Molybdenum.

Q3 MultipleChoice

Which of the following can increase the corrosion rate of carbon steel via hydrofluoric (HF) acid corrosion?

AHigh nitrogen content in process

BOxygen contamination

CHF acid concentration above 98%

DWeld hardness above 200 BHN

Correct Answer: D

Explanation:

According to API RP 571 and API RP 751:

''In HF alkylation units, carbon steel can be used if weld hardness is controlled to 200 Brinell (BHN). Exceeding this can significantly increase the corrosion rate and susceptibility to cracking.''

''Hard welds act as preferential corrosion sites due to microstructural inhomogeneity and stress concentration.''

(Reference: API RP 571, Section 4.3.3.4 -- Hydrofluoric Acid Corrosion; API RP 751, Section 5.3 -- Materials of Construction)

Thus, option D is correct.

Q4 MultipleChoice

Microbiologically induced corrosion is largely independent of the:

AWater content of the process

BPresence of hydrogen sulfide

CpH of the fluid

DVelocity of the flow stream

Correct Answer: D

Explanation:

From API RP 571 on Microbiologically Influenced Corrosion (MIC):

''MIC depends on the presence of water, nutrients, and specific microbial species such as SRB (sulfate-reducing bacteria).''

''While flow velocity may influence deposition and oxygen content, MIC can occur in both stagnant and flowing systems. Hence, it's not strongly dependent on velocity.''

Thus, option D is correct --- MIC is largely independent of flow velocity.

Q5 MultipleChoice

(What steel alloy is no longer recommended for services susceptible to HTHA?)

AMn--0.5 Mo steel

B1.25 Cr--0.5 Mo steel

C1 Cr--0.5 Mo steel

DC--0.5 Mo steel

Correct Answer: C

Explanation:

Comprehensive and Detailed Explanation From Exact Extract:

According to API RP 571 and API RP 941 (Nelson Curves), 1 Cr--0.5 Mo steel is no longer recommended for services susceptible to High-Temperature Hydrogen Attack (HTHA).

API RP 941 documents industry experience showing that 1 Cr--0.5 Mo steels have suffered HTHA damage below previously assumed safe operating limits, due to insufficient carbide stability. As a result, this material has been removed from the Nelson Curves as an acceptable choice for new construction in hydrogen service.

By contrast:

Mn--0.5 Mo, C--0.5 Mo, and 1.25 Cr--0.5 Mo steels retain higher resistance due to more stable carbide structures.

Referenced Documents (Study Basis):

API RP 571 -- Section on High-Temperature Hydrogen Attack

API RP 941 -- Updated Nelson Curves and Material Recommendations

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