Question 1

If wet electrodes or high moisture content flux is used, ________ can be charged into the steel resulting in delayed cracking.

Accepted Answer

A)  Atomic hydrogen 
B)  Hydrogen 
C)  Oxygen 
D)  H₂O

Question 2

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 (CO₂ and H₂S), amine degradation products, heat stable amine salts and other contaminants.

Accepted Answer

A)  Carbon steel 
B)  Duplex SS 
C)  300 Series SS 
D)  400 Series SS

Question 3

Which of the following is not a primary factor contributing to erosion-corrosion?

Accepted Answer

A)  Impact angle (angle that impacting particles strike metal) 
B)  Tensile strength of the metal 
C)  Velocity of impacting particles 
D)  Corrosiveness of the environment

Question 4

Hydrogen permeation or diffusion rates have been found to be minimal at pH _______ and increase at both higher and lower pH's.

Accepted Answer

A)  4 
B)  5 
C)  6 
D)  7

Question 5

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 __________.

Accepted Answer

A)  Sulfide 
B)  Caustic 
C)  Hydrogen 
D)  Water

Question 6

At a given pressure, the H₂S concentration in the sour water _________ as temperature _________.

Accepted Answer

A)  Increases, increases 
B)  Decreases, decreases 
C)  Increases, decreases 
D)  Decreases, increases

Question 7

At elevated temperatures, dissimilar weld metal cracking is aggravated by the diffusion of carbon out of the weld metal and into the base metal. The temperature at which carbon diffusion becomes a concern is above ________.

Accepted Answer

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

Question 8

Geometry, stress level, number of cycles and _________ are the predominate factors in determining the fatigue resistance of a component.

Accepted Answer

A)  Temperature 
B)  Material properties 
C)  Pressure 
D)  Velocity

Question 9

Susceptibility to temper embrittlement is largely determined by the presence of the alloying elements manganese and _______.

Accepted Answer

A)  Chromium 
B)  Moly 
C)  Silicon 
D)  None of the above

Question 10

The presence of ________ in H₂S streams increases the severity of high temperature sulfide corrosion at temperatures above about 500º F

Accepted Answer

A)  Amine 
B)  Hydrogen 
C)  Sulfides 
D)  All of the above

Question 11

__________ testing is the best method to determine the susceptibility of a material to hydrogen stress cracking.

Accepted Answer

A)  Hardness 
B)  Acoustic 
C)  SWUT 
D)  AUT

Question 12

A 5Cr-1Mo piping system in the hydrogen unit shows significant internal wall loss after 2 years in service due to CO₂ corrosion. Which material would be best suited to use to install a new pipe system?

Accepted Answer

A)  Titanium 
B)  9Cr-1Mo 
C)  A-106 Gr B 
D)  316 SS

Question 13

Vibration-induced fatigue can be eliminated or reduced through _________ and the use of supports and vibration dampening equipment. Material upgrades are not usually a solution.

Accepted Answer

A)  Hangers 
B)  Dummy legs 
C)  Design 
D)  None of the above

Question 14

Exposure to high solution strength caustic can result in general corrosion or high corrosion rates above ________.

Accepted Answer

A)  175º F 
B)  150º F 
C)  125º F 
D)  100º F

Question 15

A steam actuated soot blower has condensate in the first steam exiting the soot blower. What type of damage can be expected to be found when the furnace is brought down for maintenance and inspection?

Accepted Answer

A)  Thermal fatigue 
B)  Steam blanketing 
C)  Creep 
D)  Stress rupture

Question 16

Hydriding of titanium is a metallurgical phenomenon in which hydrogen diffuses into the titanium and reacts to form an embrittling phase. This can result in a complete loss of _________ with no noticeable sign of corrosion or loss of thickness.

Accepted Answer

A)  Strength 
B)  Ductility 
C)  Carbides 
D)  Hardness

Question 17

Resistance to sulfidation increases as the:

Accepted Answer

A)  Chromium content in the material increases. 
B)  Nickel content in the material increases. 
C)  Material's tensile strength decreases. 
D)  Material's tensile strength increases.

Question 18

SCC usually occurs at pH values above two (2). SCC tendency __________ toward the alkaline pH region

Accepted Answer

A)  Increases 
B)  Decreases 
C)  Stabilizes 
D)  None of the above

Question 19

Amine cracking has been reported down to ambient temperatures with some amines. __________ temperatures and stress levels _______ the likelihood and severity of cracking.

Accepted Answer

A)  Increasing increases 
B)  Increasing, decreases 
C)  Decreasing increases 
D)  Increasing, reduces

Question 20

Carbonate SCC can occur at relatively low levels of ________ but usually occurs at welds that have not been stressed relieved.

Accepted Answer

A)  Residual stress 
B)  Applied stress 
C)  Acid concentration 
D)  None of the above

Exam 1: Corrosion and Materials