Question 1

_________ is surface initiated cracks caused by environmental cracking of 300 Series SS and some nickel based alloys under the combined action of tensile stress, temperature and an aqueous chloride environment. The presence of dissolved oxygen increases the propensity for cracking.

Accepted Answer

A)  SSC 
B)  SOHIC 
C)  Cl SCC 
D)  HIC

Question 2

Spheroidization and graphitization are competing mechanisms that occur at overlapping temperature ranges. Spheroidization tends to occur preferentially above _______ while graphitization predominates below this temperature.

Accepted Answer

A)  1000º F 
B)  1025º F 
C)  1050º F 
D)  1100º F

Question 3

A form of mechanical fatigue in which cracks are produced as a result of dynamic loadings is _______.

Accepted Answer

A)  Spheroidization 
B)  Vibration-induced cracking 
C)  Fatigue cracking 
D)  Stress cracking

Question 4

Titanium Hydriding damage occurs primarily in sour water strippers and amine units in the overhead condensers, heat exchanger tubes and other titanium equipment operating above _________.

Accepted Answer

A)  300º F 
B)  270º F 
C)  210º F 
D)  165º F

Question 5

SIMULATION Ways to prevent thermal fatigue include reducing stress concentrators by making _______________ transitions at places where the wall thickness changes.

Accepted Answer

The answer of SIMULATION Ways to prevent thermal fatigue include...

Question 6

Alloy 400 is susceptible to LME when it comes in contact with molten ________.

Accepted Answer

A)  Cadmium 
B)  Mercury 
C)  Zinc 
D)  Lead

Question 7

_________ is the result of cyclic stress caused by variations in temperature.

Accepted Answer

A)  Creep 
B)  Thermal Fatigue 
C)  Cyclic Cracking 
D)  Stress Corrosion Cracking

Question 8

For a specific material, HTHA is dependent on temperature, hydrogen partial pressure, time and _________.

Accepted Answer

A)  Stress 
B)  Pressure 
C)  Velocity 
D)  Alloy composition

Question 9

With cooling water corrosion, _________ oxygen content tends to ________ carbon steel corrosion rates.

Accepted Answer

A)  Increasing, increasing 
B)  Decreasing, decreasing 
C)  Decreasing, increasing 
D)  Increasing, decreasing

Question 10

Foul smelling water may be a sign of fouling and/or _______

Accepted Answer

A)  MIC 
B)  HIC 
C)  SOHIC 
D)  All of the above

Question 11

The creep threshold temperature for 1 ¼, 2 ¼, 5 and 9 Cr is ________.

Accepted Answer

A)  600º F 
B)  700º F 
C)  800º F 
D)  1000º F

Question 12

Steam blanketing is when the heat flow balance is disturbed; individual bubbles join to form a steam blanket, a condition known as Departure from Nucleate Boiling (DNB). Once a steam blanket forms, tube rupture can occur rapidly, as a result of _________.

Accepted Answer

A)  Thermal fatigue 
B)  Short term overheating 
C)  Brittle fracture 
D)  Stress

Question 13

Corrosion in boiler feedwater and condensate return systems is usually the result of dissolved gases, oxygen and _______.

Accepted Answer

A)  Carbon monoxide 
B)  H₂O 
C)  Temperature 
D)  Carbon Dioxide

Question 14

Thermal fatigue cracks usually initiate on the _________ of the component. They are generally wide and filled with oxides due to the elevated temperatures.

Accepted Answer

A)  Surface 
B)  ID 
C)  Welds 
D)  None of the above

Question 15

Which of these materials are not susceptible to Spheroidization?

Accepted Answer

A)  Carbon steel 
B)  9Cr-1Mo 
C)  316 SS 
D)  Both A and B

Question 16

Cooling water corrosion can result in many different forms of damage including general corrosion, pitting corrosion, ________, stress corrosion cracking and fouling.

Accepted Answer

A)  MIC 
B)  HIC 
C)  SOHIC 
D)  All of the above

Question 17

Since all fuels contain some amount of sulfur, sulfuric and sulfurous acid __________ can occur if the metal temperature is below this temperature.

Accepted Answer

A)  Corrosion 
B)  Pitting 
C)  Dew point corrosion 
D)  All of the above

Question 18

The removal of a material's protective scale by impacting materials is called:

Accepted Answer

A)  Erosion 
B)  Erosion-corrosion 
C)  Erosion or erosion-corrosion 
D)  IPRSC (imparting particle removal of scale corrosion)

Question 19

General or localized corrosion of carbon steels and other metals caused by dissolved salts, gases, organic compounds or microbiological activity is called _______.

Accepted Answer

A)  Cooling water corrosion 
B)  Oxidation 
C)  MIC 
D)  None of the above

Question 20

Alloys with nickel content above _________ are highly resistant to Cl SCC. The greatest susceptibility is 8% to 12% nickel.

Accepted Answer

A)  15% 
B)  20% 
C)  30% 
D)  35%

Exam 1: Corrosion and Materials