API 571

Question 1

What is the temperature when high strength caustic causes serious corrosion in CS and 300 SS?

Answer 1

> 150°F

API 571 par 4.3.10.6c

Question 2

At what temperature does CUI become more severe?

Answer 2

212°F to 350°F (API 571)
and
120°F to 200°F (API 575)

API 571 par 4.3.3.3b and API 575 par 8.2.7

Question 3

Brittle fracture affects what units and equipment?

Answer 3

Units processing light hydrocarbons, like alky, olfins, polymer units.

API 571 par 5.2.7.4b

Question 4

Where is atmospheric corrosion most severe?

Answer 4

Marine environments and moist polluted industrial environments

API 571 par 4.3.2.1

Question 5

What are prevention methods for atmospheric corrosion?

Answer 5

Surface preparation and proper coating application

API 571 par 4.3.2.6

Question 6

What are the criticial factors for chloride stress corrosion cracking?

Answer 6

Corrdent, Temperature, Stress

API 571 par 4.5.1.3

Question 7

Where is MIC most often found?

Answer 7

Stagnant or low flow areas

API 571 par 4.3.8.3a

Question 8

What are the affected units for caustic stress corrosion cracking?

Answer 8

Sulfuric and hydrofluric alkylation units

API 571 par 4.5.3.4a

Question 9

How can caustic stress corrosion cracking be prevented?

Answer 9

PWHT at 1150°F

API 571 par 4.5.3.6a

Question 10

What is the most common method of monitoring underground structures for soil composition?

Answer 10

Measuring the structure to soil potential?

API 571 4.3.9.7a

Question 11

An inspector is checking a tank that contains water bottoms and a hydrocarbon product that has been neutralized by using caustic. He suspects there may be caustic corrosion. Where would be a likely place for this to occur?

Answer 11

At the water line and in areas where caustic concentrations could collect.

API 571 par 4.3.10.5 (b&c)

Question 12

Sulfuric acid promotes general and localized corrosion of carbon steel and other alloys. Where is the most affected zones for severe corrosion in carbon steel?

Answer 12

Heat affected zones

API 571 5.1.1.11.1

Question 13

What happens to the corrosion rate of carbon steel in sulfuric acid solution if your flow velocity is 5fps?

Answer 13

Increases significantly if flow exceeds 2-3fps

API 571 par 5.1.1.11.3c

Question 14

What happens when water is mixed with sulfuric acid?

Answer 14

Diluted acid causes heat to be realease, increasing corrosion rates

API 571 par 5.1.1.11.3d

Question 15

What is one good way to prevent sulfuric acid corrosion?

Answer 15

Add caustic to neutralize the acid

API 571 par 5.1.11.6c

Question 16

What is the maximum internal pressure for tanks per API 650 & API 653

Answer 16

2.5 psig