API 653 Exam Chapter 4 - Reasons for Inspection

API 653 Exam Chapter 4 -Reasons for Inspection: DamageMechanisms

Now try this first set of self-test questions covering the first two DMs.

4.5 API 571 practice questions (set 1)

Take a Free API 653 Exam Chapter 4 Practice test with Latest API 571 Practice Question and Answers (Set 1, 2, and 3)

Q1. API 571: brittle fracture
Which of these is a description of brittle fracture?

(a) Sudden rapid fracture of material with plastic deformation

(b) Sudden rapid fracture of material without plastic deformation

(d) Fracture caused by reaction with sulphur compounds

Q2. API 571: brittle fracture: affected materials
Which of these storage tank construction materials are particularly susceptible to brittle fracture?

(a) Plain carbon and high alloy steels

(b) Plain carbon, low alloy, and 300 series stainless steels

(d) High-temperature resistant steels

Q3. API 571: brittle fracture: critical factors
At what temperature is a brittle fracture of a storage tank most likely to occur?

(a) Temperatures above 400 °C

(b) Temperatures above the Charpy impact transition temperature

(d) In the range 20–110 °C

Q4. API 571: brittle fracture
Which of these activities is unlikely to result in a high risk of brittle fracture of a storage tank?

(a) Repeated hydro-testing above the Charpy impact transition temperature

(b) Initial hydro testing at low ambient temperatures

(d) Autorefrigeration events in low pressure tanks

Q5. API 571: brittle fracture: prevention/mitigation
What type of material change will reduce the risk of brittle fracture?

(a) Use a material with lower toughness

(b) Use a material with lower impact strength

(d) Use a thicker material section

Q6. API 571: brittle fracture: appearance
Cracks resulting from brittle fracture will most likely be predominantly:

(a) Branched

(b) Straight and non-branching

(d) Accompanied by localized necking around the crack

Q7. API 571: mechanical fatigue: description
What is mechanical fatigue?

(a) The result of excessive temperatures

(b) The result of temperature-induced corrosion

(d) The result of cyclic stresses caused by dynamic loadings

Q8. API 571: mechanical fatigue: critical factors
As a practical rule, resistance to mechanical fatigue is mainly determined by what aspect of a piece of equipment?

(a) Its design

(b) Its operation

(d) The material’s heat treatment

Q9. API 571: mechanical fatigue: appearance
What will a fracture face of a component that has failed by mechanical fatigue most likely exhibit?

(a) Fine branching cracks

(b) Dagger-shaped lines

(d) Chevron marks

10.

Q10. API 571: prevention/mitigation
Mechanical fatigue cracking is best avoided by:

(a) Specifying long weld leg lengths

(b) Blending weld toes

(d) Using a high strength material

11.

4.7 API 571 practice questions (set 2
Q1. API 571: atmospheric corrosion
Atmospheric corrosion is primarily caused by:

(a) Wind

(b) Water

(d) Daily or seasonal temperature cycles

12.

Q2. API 571: atmospheric corrosion
As a practical rule, atmospheric corrosion:

(a) Only occurs under insulation

(b) Maybe localized or general (widespread)

(d) Is generally widespread

13.

Q3. API 571: atmospheric corrosion: critical factors
A typical atmospheric corrosion rate in mils (1 mil = 0.001 inches) per year (mpy) of steel in an inland location with moderate precipitation and humidity is:

(a) 1–3 mpy

(b) 5–10 mpy

(d) 50–100 mpy

14.

Q4. API 571: CUI: critical factors
Which of these metal temperature ranges will result in the most severe CUI?

(a) 0–51 °C

(b) 100–121 °C

(d) 250+°C

15.

Q5. API 571: CUI: appearance
Which other corrosion mechanism often accompanies CUI in 300 series stainless steels?

(a) HTHA (high-temperature hydrogen attack)

(b) Erosion–corrosion

(d) SCC

16.

Q6. API 571: CUI: affected equipment
Which area of a lagged storage tank shell would you say could be particularly susceptible to CUI?

(a) Around nozzles

(b) Around lagging support rings and wind girders

(d) On the windward side

17.

Q7. API 571: CUI: appearance
Once lagging has been removed from an unpainted tank structure, CUI normally looks like this:

(a) Deep gouges

(b) Bulges

(d) White or grey deposit

18.

Q8. API 571: CUI: prevention/mitigation
Which of these actions may reduce the severity of CUI on a lagged storage tank?

(a) Adding additional layers of insulation

(b) Using calcium silicate insulation

(d) Using closed-cell foam glass insulation

19.

Q9. API 571: CUI: mitigation
CUI conditions can be identified on an in-use lagged storage tank using:

(a) Neutron backscatter

(b) X-ray fluorescence

(d) Phased array

20.

Q10. API 571: CUI: critical factors
Which of these can make storage tank CUI worse?

(a) Elevated tank temperatures above 200 °C

(b) Airborne contaminants

(d) Low temperatures below 10 °C

21.

Q11. API 571: soil corrosion
What is the main parameter measured to assess the corrosivity of the soil underneath a storage tank?

(a) Acidity

(b) Alkalinity

(d) Resistivity

22.

Q12. API 571: soil corrosion: appearance
What would you expect the result of soil corrosion to look like?

(a) Branched and dagger-shaped cracks

(b) Isolated, large and deep individual pits

(d) External corrosion with wall thinning and pitting

23.

Q13. API 571: soil corrosion: protection
Which of these would be used to reduce the amount of soil corrosion in a storage tank?

(a) Caustic protection

(b) Cathodic protection

(d) More post-weld heat treatment

24.

Q14. API 571: soil corrosion: critical factors
What effect does metal temperature have on the rate of soil corrosion?

(a) None

(b) The corrosion rate increases with temperature

(d) There will be minimal soil corrosion below 0 °C

25.

Q15. API 571: soil corrosion: critical factors
Which of these areas would you expect to suffer the worst soil corrosion?

(a) Soil-to-air interfaces

(b) Any areas in contact with the soil of pH 7

(d) Areas in contact with soil that has plants or moss growing in it

26.

4.9 API 571 practice questions (set 3).
Q1. API 571: MIC: description
MIC is caused by the corrosive effects of:

(a) Living organisms

(b) The degradation of organisms after they have died

(d) Organisms reacting with chlorides

27.

Q2. API 571: MIC: appearance
What does MIC typically look like?

(a) Uniform wall thinning with a ‘sparkling’ corroded surface

(b) Localized pitting under deposits

(d) A dry flaky appearance

28.

Q3. API 571: MIC: critical factors
Under what pH values does MIC occur?

(a) Almost any pH 0–12

(b) Mainly pH 1–6 (acidic)

(d) Mainly pH 5–7

29.

Q4. API 571: MIC: critical factors
What is the maximum temperature under which you would expect MIC to occur?

(a) 60 °C

(b) 113 °C

(d) 250 °C

30.

Q5. API 571: MIC: prevention
MIC is best controlled by:

(a) Reducing flow velocities

(b) Recirculating the system with water

(d) Lagging the system to keep the temperature up

31.

Q6. API 571: description of chloride SCC
Chloride SCC is also called (in API terminology):

(a) Embrittlement cracking

(b) Environmental cracking

(d) Chevron cracking

32.

Q7. API 571: SCC: affected materials
Chloride SCC is known to particularly attack what type of tank construction material?

(a) Low carbon steel

(b) Low alloy steel

(d) Older, low-grade steel (common in riveted tanks)

33.

Q8. API 571: SCC: critical factors
What is the lower limit of chloride content at which chloride SCC stops occurring?

(a) There is no lower limit

(b) 100 ppm

(d) 1 ppm

34.

Q9. API 571: SCC: critical factors
What is the temperature above which chloride SCC becomes more likely under chloride process conditions?

(a) Above 0 °F

(b) Above 60 °F

(d) Above 140 °F

35.

Q10. API 571: chloride SCC: appearance
What kind of corrosion deposit is normally seen on the surface of a material suffering from chloride SCC?

(a) White powdery deposit

(b) Small blisters or pits (may be hiding under the paint)

(d) None

36.

Q11. API 571: chloride SCC: inspection
Which of these techniques is best able to find chloride SCC?

(a) RT (radiographic testing)

(b) UT (ultrasonic testing)

(d) MT (magnetic testing)

37.

Q12. API 571: chloride SCC: morphology
What shape are chloride SCC cracks?

(a) Dagger-shaped

(b) Fine and branching

(d) Zigzag, starting from stress concentrations or sharp edges

38.

Q13. API 571: caustic SCC
Caustic SCC in storage tanks is also called:

(a) Acidic SCC

(b) Caustic embrittlement

(d) Caustic oxidation

39.

Q14. API 571: caustic SCC location
Caustic SCC is particularly common around which locations in storage tanks?

(a) Non-post-weld heat-treated welds

(b) Post-weld heat-treated welds in thick section materials

(d) Nozzle and manway welds

40.

Q15. API 571: caustic SCC: critical factors
Caustic SCC can be caused at caustic concentrations of:

(a) Any concentration; there is no safe lower limit

(b) 0.1–1 ppm caustic

(d) 50–100 ppm caustic

41.

Q16. API 571: caustic SCC: appearance
Caustic SCC cracks have a greater tendency to propagate:

(a) Parallel to a weld

(b) Across a weld (transverse)

(d) In a direction roughly at 45 degrees from the weld line

42.

Q17. API 571: sulphuric acid corrosion: affected materials
Which of these tank fittings construction materials would be most resistant to sulphuric acid corrosion?

(a) High silicon cast iron

(b) 316 stainless steel

(d) Carbon–manganese steel

43.

Q18. API 571: sulphuric acid corrosion: critical factors
Which of these sulphuric acid conditions will result in the worst corrosion of a tank construction material?

(a) Low acid concentrations

(b) High acid concentrations

(d) High acid concentrations plus high flow velocity

44.

Q19. API 571: sulphuric acid corrosion: prevention
Which of these actions will reduce the effect of corrosion in a system susceptible to sulphuric acid corrosion?

(a) Washing with demineralized water

(b) Washing with a caustic solution

(d) Abrading the surface to remove the oxide film

45.

Q20. API 571: sulphuric acid corrosion: affected equipment
If a storage tank with trace heating contains a sulphuric acid-rich product, where would you expect the worst corrosion to occur?

(a) The roof

(b) The floor

(d) Halfway up the shell

Question 1 of 45

API 653 Exam Chapter 4 – Reasons for Inspection: Damage Mechanisms. Understand key concepts and enhance your preparation. Take a free online API 653 practice test to improve your exam results and boost your confidence!

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Try these practice questions.

API 571 practice questions (set 2)

The third group of API 571 DMs

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