Question 1

___________ is the result of cyclic stresses caused by variations in temperature.

Accepted Answer

A)  Cyclic cracking 
B)  Stress cracking 
C)  Stress fatigue 
D)  Thermal fatigue

Question 2

Carbonate SCC may easily be mistaken for SSC or SOHIC; however, the carbonate cracks are usually ________ the toe of the weld and have multiple parallel cracks.

Accepted Answer

A)  Further from 
B)  Closer to 
C)  Diagonal to 
D)  Perpendicular to

Question 3

Which of the following materials are affected by mechanical fatigue cracking?

Accepted Answer

A)  Only carbon steel 
B)  Only carbon steel and chromes 
C)  Only carbon steel, and high nickel alloys 
D)  All materials

Question 4

Carbon dioxide (CO₂) corrosion results when CO₂ dissolves in water to form ________.

Accepted Answer

A)  Carbon monoxide 
B)  Carbonic acid 
C)  Hydrofluoric acid 
D)  None of the above

Question 5

Areas of vulnerability in sulfuric acid Alkylation units include reactor effluent lines, reboilers, deisobutanizer, overhead systems and the _________ treating system.

Accepted Answer

A)  Caustic 
B)  Sulfuric acid 
C)  Catalyst 
D)  H₂S

Question 6

A loss in ductility of high strength steels due to the penetration of atomic hydrogen can lead to brittle cracking called hydrogen embrittlement. Which of the following materials is susceptible to HE.

Accepted Answer

A)  Carbon steel 
B)  400 Series SS 
C)  Low alloy steel 
D)  All of the above

Question 7

The graphitization rate ____________ with increasing temperature

Accepted Answer

A)  Increases 
B)  Decreases 
C)  Stops 
D)  Proceeds

Question 8

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

Accepted Answer

A)  650º F 
B)  700º F 
C)  750º F 
D)  800º F

Question 9

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

Accepted Answer

A)  Branches 
B)  Laterals 
C)  Stress concentrations 
D)  Grinding marks

Question 10

A form of thermal cracking, __________, can occur when high and nonuniform thermal stresses develop over a relatively short period of time in a piece of equipment due to differential expansion and contraction.

Accepted Answer

A)  Thermal expansion 
B)  Thermal stress 
C)  Thermal shock 
D)  Linear expansion

Question 11

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

Accepted Answer

A)  Transition limit. 
B)  Endurance limit. 
C)  Hardening limit. 
D)  Speed limit.

Question 12

Caustic is sometimes added to process streams for ________ or as a reactant.

Accepted Answer

A)  Stability 
B)  Corrosion control 
C)  Neutralization 
D)  Inhibiting

Question 13

______ is most likely found in hard welds and heat affected zones and in high strength components.

Accepted Answer

A)  SOHIC 
B)  HIC 
C)  Carburization 
D)  SSC

Question 14

Heat treatment can have a significant effect on the toughness and hence fatigue resistance of a metal. In general, ________ grained microstructures tend to perform better than _________ grained.

Accepted Answer

A)  Fine, Course 
B)  Austenitic, martensitic 
C)  Course, Fine 
D)  Martensitic, austenitic

Question 15

The most important factors affecting graphitization are the chemistry, stress, temperature and _______.

Accepted Answer

A)  Velocity 
B)  Time at exposure 
C)  Pressure 
D)  Ductility

Question 16

____________ is the reduction in toughness due to a metallurgical change that can occur in some low alloy steels as a result of long-term exposure in the temperature range of about 650º F to 1100º F.

Accepted Answer

A)  Hardening 
B)  Graphitization 
C)  Spheroidization 
D)  Temper embrittlement

Question 17

SSC is a form of hydrogen stress cracking resulting from the absorption of atomic hydrogen that is produced by the ______ corrosion process on the metal surface.

Accepted Answer

A)  HCl 
B)  HF 
C)  Sulfide 
D)  Wet H₂S

Question 18

Which of the following is not a prime candidate for thermal fatigue?

Accepted Answer

A)  Coke drums 
B)  Steam actuated soot blowers 
C)  Mix points of hot and cold streams 
D)  600 psig steam piping 
E)  Welds joining materials having different coefficients of expansion

Question 19

A 6", A106 Gr B, flanged line carrying caustic wash water at 200º F has signs of atmospheric corrosion. Which of the following may have help accelerate the corrosion?

Accepted Answer

A)  Sulfides 
B)  Fly ash 
C)  Caustic 
D)  None of the above

Question 20

A quick test for embrittlement from _________ is a bend test or crush test. Unaffected material will be crushed in a ductile fashion while embrittled components will crack with no signs of ductility.

Accepted Answer

A)  Titanium Hydriding 
B)  Temper embrittlement 
C)  Caustic embrittlement 
D)  None of the above.

Exam 1: Corrosion and Materials