Question 1

Which of the following materials are susceptible to nitriding?

Accepted Answer

A)  Carbon steel 
B)  300 Series SS 
C)  400 Series SS 
D)  All of the above

Question 2

Decarburization results in a __________, which can be confirmed by hardness testing.

Accepted Answer

A)  Hardness 
B)  Softness 
C)  Brittleness 
D)  Oxidizing

Question 3

For some materials such as titanium, carbon steel and low alloy steel, the number of cycles to fatigue fracture decreases with ________ until an endurance limit is reached. Below this endurance limit, fatigue cracking will not occur, regardless of the number of cycles.

Accepted Answer

A)  Temperature increases 
B)  Stress endurance 
C)  Pressure decreases 
D)  None of the above

Question 4

Stress relief and stabilization heat treatment of 300 Series SS for maximizing chloride SCC and PASCC resistance can cause ____________ problems, especially in thicker sections.

Accepted Answer

A)  Thermal fatigue 
B)  Reheat cracking 
C)  Hydrogen 
D)  HIC

Question 5

Which of these materials are not susceptible to PASCC?

Accepted Answer

A)  Carbon steel 
B)  300 Series SS 
C)  400 Series SS 
D)  Both A and C

Question 6

_________ acid is most often used as a catalyst in polymerization units.

Accepted Answer

A)  Polythionic 
B)  Naphthenic 
C)  Phosphoric 
D)  Sulfuric

Question 7

Cracking susceptibility increases with __________ pH and carbonate concentration.

Accepted Answer

A)  Increasing 
B)  Decreasing 
C)  Low 
D)  High

Question 8

Key factors affecting thermal fatigue are the magnitude of the temperature and the __________.

Accepted Answer

A)  Number of cycles 
B)  Pressure 
C)  Stress 
D)  Alloy composition

Question 9

For carbon steel, common velocity limits are generally limited to _________ fps for rich amine and _______ fps for lean amine.

Accepted Answer

A)  8-10, 30 
B)  6-9, 15 
C)  4-8, 10 
D)  3-6, 20

Question 10

___________ cracking has been a major problem in coke drum shells.

Accepted Answer

A)  Stress 
B)  Carburization 
C)  Thermal fatigue 
D)  Sulfide

Question 11

Which of the following materials is affected by high temperature corrosion?

Accepted Answer

A)  Carbon steel 
B)  300 Series SS 
C)  400 Series SS 
D)  All of the above

Question 12

Which of these materials is not susceptible to amine cracking?

Accepted Answer

A)  Carbon steel 
B)  300 Series SS 
C)  400 Series SS 
D)  Both B and C

Question 13

Carbon dioxide corrosion results when CO₂ dissolves in water to form _________ acid.

Accepted Answer

A)  Sulfuric 
B)  Hydrochloric 
C)  Carbonic 
D)  None of the above

Question 14

Protection in a boiler from boiler feed water corrosion is accomplished by:

Accepted Answer

A)  Injecting chlorines to kill microbiological bugs. 
B)  Injecting caustic to lower the ph to < 4.0. 
C)  Lowering solids content in boiler feed water to less than 50 ppm. 
D)  Maintaining a protective corrosion layer of magnetite (Fe3O4).

Question 15

Regular and controlled carbon grades of stainless steels such as types 304/304H and 316/316H are particularly susceptible to sensitization in the weld HAZ. Low carbon "L" grades are less susceptible and usually can be welded without sensitizing. The "L" grades will not sensitize provided long term operating temperatures do not exceed about __________.

Accepted Answer

A)  700º F 
B)  750º F 
C)  800º F 
D)  900º F

Question 16

The creep threshold temperature for carbon steel is ________.

Accepted Answer

A)  315º C 
B)  371º C 
C)  426º C 
D)  538º C

Question 17

Temper embrittlement _________ be prevented if the material contains critical levels of the embrittling impurity elements and is exposed in the embrittling range.

Accepted Answer

A)  Can 
B)  Cannot 
C)  Will 
D)  None of the above

Question 18

Caustic stress corrosion cracking typically propagates _______ to the weld in adjacent base metal but can occur in the weld deposit or heat affected zone.

Accepted Answer

A)  Transverse 
B)  Perpendicular 
C)  Parallel 
D)  Across

Question 19

Although cracks may be seen visually, crack detection for caustic stress corrosion cracking is best detected by WFMT, EC, RT and ______.

Accepted Answer

A)  PT 
B)  MT 
C)  ACFM 
D)  All of the above

Question 20

With short term overheating, time to failure will ___________ as internal pressures or loading decrease.

Accepted Answer

A)  Increase 
B)  Decrease 
C)  Remain the same 
D)  None of the above

Exam 1: Corrosion and Materials