API 510 Cheat Sheet 2026

The 30 highest-yield API 510 facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. Why is Magnetic Particle Testing limited to ferromagnetic materials? → Only ferromagnetic materials can retain magnetic fields
2. Which type of pressure relief valve is MOST sensitive to variable or high superimposed back pressure, which can raise its effective set pressure? → Conventional spring-loaded pressure relief valve
3. Why is personal protective equipment (PPE) essential during inspection? → To protect inspectors from potential hazards
4. Stress corrosion cracking (SCC) in pressure vessels requires which three conditions to occur simultaneously? → Susceptible material, tensile stress, and corrosive environment
5. What should be monitored during a pressure hold period? → Pressure gauge readings for any pressure drops indicating leaks
6. Erosion-corrosion in pressure vessels is characterized by accelerated metal loss caused by: → Combined mechanical abrasion and corrosive attack from flowing fluid
7. Which technique is most suitable for volumetric inspection? → Radiographic Testing
8. Which preheat practice is used to prevent hydrogen cracking in high-strength low-alloy (HSLA) steel repair welds? → Maintaining elevated preheat and interpass temperatures throughout welding
9. Which document provides the primary FFS methodology referenced by API 510 for pressure vessels? → API 579-1/ASME FFS-1
10. Which ASME Section VIII Div. 1 paragraph sets requirements for the minimum design metal temperature (MDMT) and the impact test exemption curves? → UCS-66
11. API RP 571 recommends which measure as the primary mitigation for alkaline stress corrosion cracking (caustic SCC) in carbon steel pressure vessels? → Applying PWHT to all carbon steel welds above caustic SCC threshold conditions
12. What role does process fluid toxicity play in an RBI consequence of failure analysis? → It elevates the safety/health consequence, increasing overall risk ranking
13. What does the designation 'SA-516 Gr. 70' indicate for a pressure vessel shell plate? → ASTM plate steel with 70,000 psi minimum ultimate tensile strength
14. A 'cold-wall' vessel in hydrogen service where the insulation maintains the shell below 400°F — what Nelson Curve classification governs material selection? → The curves apply based on the actual metal temperature (shell temperature)
15. Why is thickness data trending important in pressure vessel management? → It reveals corrosion rate changes and enables remaining life prediction
16. Under API 510, pressure vessels subject to internal corrosion shall have the remaining corrosion allowance measured to determine the: → Remaining life and next inspection interval
17. What is required for a welded joint to be accepted under ASME? → It must be inspected and meet quality criteria
18. According to API 510 and the NBIC, after completing an alteration on a pressure vessel, the alteration organization must notify: → The jurisdiction (state or local authority) and the authorized inspection agency
19. Which welding defect is characterized by the failure of fusion between the weld metal and base metal? → Lack of fusion
20. In API 510 inspection practice, which corrosion mechanism is most commonly associated with crude oil distillation overhead systems? → Hydrochloric acid (HCl) dew point corrosion
21. Which type of pressure relief device provides zero leakage before activation and is non-reclosing after operation? → Rupture disk
22. Which NDT method is most suitable for detecting surface cracks in non-porous materials? → Liquid Penetrant Testing
23. Positive Material Identification (PMI) using X-ray fluorescence (XRF) is most effective for verifying which material property? → Alloy composition of chrome-moly or stainless steel components
24. Per ASME Section VIII Div. 1, what hydrostatic test pressure is required for a completed vessel with an MAWP of 250 psi? → 375 psi
25. Under ASME Section VIII Div. 1, which UG paragraph governs the design of formed heads under internal pressure? → UG-32
26. Which organization enforces safety regulations in industrial workplaces? → OSHA
27. In radiographic examination, what is geometric unsharpness (Ug) primarily controlled by? → Source size, source-to-object distance, and object-to-film distance
28. According to API 510, who must authorize a repair to a pressure vessel before work begins? → The vessel owner/user
29. Which form of corrosion attacks along grain boundaries of the metal, often caused by chromium depletion in stainless steels? → Intergranular corrosion
30. What is the minimum Charpy V-notch energy absorption required for weld metal and HAZ per ASME Section VIII Division 1 UG-84? → 20 ft-lb (27 J) average with 15 ft-lb (20 J) minimum per specimen