Corrosion and Materials

Here you have the best API API-571 practice exam questions

  • You have 454 total questions across 91 pages (5 per page)
  • These questions were last updated on February 15, 2026
  • This site is not affiliated with or endorsed by API.
Question 1 of 454
__________ is a change in the microstructure of certain carbon steels and 0.5 Mo steels after long term operation in the 800º F to 1100º F range.
Answer

Suggested Answer

The suggested answer is A.

Graphitization is a change in the microstructure of certain carbon steels and 0.5 Mo steels after long term operation in the 800º F to 1100º F range. During this process, carbon precipitates from the steel matrix as graphite, leading to a reduction in the toughness and strength of the steel.

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Question 2 of 454
What structure is 304 stainless steel?
Answer

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The suggested answer is B.

304 stainless steel is classified as an austenitic stainless steel. This category is known for its excellent corrosion resistance and weldability, largely due to its high chromium and nickel content. Austenitic stainless steels are also non-magnetic and cannot be hardened by heat treatment. Common applications of 304 stainless steel include kitchen equipment, chemical processing equipment, and food processing machinery.

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Question 3 of 454
_________ is the result of cyclic stress caused by variations in temperature.
Answer

Suggested Answer

The suggested answer is B.

Thermal fatigue is the phenomenon that occurs due to cyclic stress caused by variations in temperature. It typically results from repeated thermal cycling, which can cause materials to crack or fail over time as they expand and contract with temperature changes.

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Question 4 of 454
General or localized corrosion of carbon steels and other metals caused by dissolved salts, gases, organic compounds or microbiological activities is called ________.
Answer

Suggested Answer

The suggested answer is C.

Cooling water corrosion refers to the general or localized corrosion of carbon steels and other metals caused by dissolved salts, gases, organic compounds, or microbiological activities in cooling water systems. This type of corrosion is specifically related to conditions found in cooling water environments, making it the most suitable answer for the question.

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Question 5 of 454
What structure is 410 stainless steel?
Answer

Suggested Answer

The suggested answer is A.

410 stainless steel is categorized as martensitic. Martensitic stainless steels are known for their high strength and hardness, along with moderate corrosion resistance. They typically have higher carbon content and can be heat treated to provide a range of mechanical properties. Types 410, 416, 420, 440A, 440B, and 440C are indeed part of the martensitic family.

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About the API API-571 Certification Exam

About the Exam

The API API-571 (Corrosion and Materials) validates your knowledge and skills. Passing demonstrates proficiency and can boost your career prospects in the field.

How to Prepare

Work through all 454 practice questions across 91 pages. Focus on understanding the reasoning behind each answer rather than memorizing responses to be ready for any variation on the real exam.

Why Practice Exams?

Practice exams help you familiarize yourself with the question format, manage your time, and reduce anxiety on the test day. Our API-571 questions are regularly updated to reflect the latest exam objectives.