Q18. (What is the minimum pH value where chloride stress corrosion cracking begins to occur?)

Q19. Fatigue cracks usually initiate on the surface at notches or __________ under cyclic loading.

Q20. Damage from sigma phase appears in the form of ________.

Q21. __________ are the most common type of equipment susceptible to carburization in the refining industry.

Q22. Carburization can be confirmed by substantial increases in _______ and loss of __________.

Q23. With high temperature sulfide corrosion (Sulfidization), noticeable increases may be found downstream of _________ injection points.

Q24. (What nondestructive examination (NDE) technique requires the least amount of surface preparation to locate wet H#S damage mechanisms?)

Q25. Sour water corrosion in _________ containing environments may be accompanied by carbonate SCC.

Q26. Which of these materials are susceptible to brittle fracture?

Q27. Hydrogen blisters may form as surface bulges on the ID, the OD on within the wall thickness of a pipe or pressure vessel. Blistering occurs from hydrogen generated by ______, not hydrogen gas from the process stream.

Q28. Which of the following materials is not susceptible to high temperature hydrogen attack?

Q29. Temper embrittlement is a metallurgical change that is not readily apparent and can be confirmed through
________.

Q30. In HF service, carbon steel forms a protective _________ scale in dry concentrated acid. Loss of the protective scale through high velocities or turbulence will result in greatly accelerated corrosion rates.

Q31. Sour water corrosion in _________ containing environments may be accompanied by carbonate SCC.

Q32. Fatigue will not occur in carbon steel if stresses are below the:

Q33. Amine corrosion refers to the general and/or localized corrosion that occurs principally on
_________ in amine treating processes. Corrosion is not caused by the amine itself, but results from dissolved acid gases (CO(2) and H(2)S), amine degradation products, heat stable amine salts and other contaminants.

Q34. Graphitization can be prevented by using chromium containing low alloys steels for long-term exposure above
________.

Q35. Steel hardness, __________ and stress are critical factors in causing hydrogen stress cracking.

Q36. With sulfidation, the presence of oxygen ________ corrosion

Q37. Hydrogen stress cracking is the same mechanism that is responsible for sulfide stress corrosion cracking in wet H²S environments except that HF acid is generating the __________.

Q38. Changing to a more corrosion resistant and/or higher hardness material _________ improve cavitation resistance.

Q39. Internal galvanic corrosion in piping near the joint of two dissimilar metals is best detected by external: