Question 1

Which of the following materials is least affected by atmospheric corrosion?

Accepted Answer

A)  Carbon steel 
B)  Chromes 
C)  Stainless steels 
D)  Copper alloyed with aluminum

Question 2

Temperature, ________ and stress are critical factors of stress rupture. This is usually found in furnaces with coking tendencies and fired heater tubes.

Accepted Answer

A)  Pressure 
B)  Ductility 
C)  Time 
D)  Tensile strength

Question 3

In a pump, the difference between the actual pressure, or head, of a liquid available (measured on the suction side) and the vapor pressure of that liquid is called Net Positive Suction Head (NPSH) available. The minimum head required to prevent cavitation with a given liquid at a given flow rate is called Net Positive Suction Head __________. Inadequate NPSH can result in cavitation.

Accepted Answer

A)  Surplus 
B)  Required 
C)  Reserve 
D)  None of the above

Question 4

Which of the following is not a primary initiating point for thermal fatigue?

Accepted Answer

A)  Notches 
B)  Rounded pits 
C)  Nozzle-to-shell welds 
D)  Weld toes

Question 5

Corrosion protection in the boiler is accomplished by laying down and continuously maintaining a layer of _____.

Accepted Answer

A)  Manganese 
B)  Magnetite 
C)  Carbon monoxide 
D)  Carbonate

Question 6

__________ is a form of damage found mostly in older vintage carbon steels and C-0.5 Mo low alloy steels under the combined effects of deformation and aging at an intermediate temperature.

Accepted Answer

A)  Spheroidization 
B)  Thermal fatigue 
C)  Strain aging 
D)  None of the above

Question 7

Thermal fatigue cracks usually:

Accepted Answer

A)  Initiate on the surface of the component. 
B)  Initiate in the subsurface of the component. 
C)  Grow very rapidly (at the speed of sound in the material). 
D)  Are very tight and narrow.

Question 8

____________ are characterized by a localized loss in thickness in the form of pits, grooves, gullies, waves, rounded holes and valleys. These losses often exhibit a directional pattern.

Accepted Answer

A)  Erosion 
B)  Corrosion/Erosion 
C)  Environmental corrosion 
D)  Both A and B

Question 9

Sensitization occurs in the _____ to _______ range.

Accepted Answer

A)  800º F, 1400º F 
B)  750º F, 1500º F 
C)  600º F, 1120º F 
D)  1000º F, 1750º F

Question 10

Stainless steel cyclones, piping ductwork and valves in high temperature FCC regeneration service are susceptible areas for _________.

Accepted Answer

A)  Brittle fracture 
B)  Sigma phase 
C)  Cavitation 
D)  Corrosion fatigue

Question 11

Units where graphitization may be suspected are the FCCU and the _____ unit.

Accepted Answer

A)  Hydrotreater 
B)  Coker 
C)  Alky 
D)  None of the above

Question 12

Soils having high moisture content, high dissolved salt concentrations and high ________ are the most corrosive.

Accepted Answer

A)  Oxygen content 
B)  Resistivity 
C)  Acidity 
D)  All of the above

Question 13

Lean amine is generally not corrosive because they have either low conductivity and/or high pH. Corrosion rates increase with increasing temperatures, particularly in rich amine service. Temperatures above _________ can result in acid gas flashing and severe localized corrosion.

Accepted Answer

A)  170º F 
B)  190º F 
C)  220º F 
D)  240º F

Question 14

_________ is most likely found in hard weld and heat-affected zones and in high strength components.

Accepted Answer

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

Question 15

________ greatly increases the probability and severity of blistering, HIC and SOHIC damage.

Accepted Answer

A)  Acids 
B)  Caustics 
C)  Amines 
D)  Cyanides

Question 16

In general, the resistance of carbon steel and other alloys to High temperature corrosion is determined by the ________ content of the material.

Accepted Answer

A)  Molybdenum 
B)  Chromium 
C)  Carbon 
D)  All of the above

Question 17

Carbonate stress corrosion cracking is the term applied to surface breaking or cracks that occur adjacent to carbon steel welds under the combined action of ____________ and ___________ in carbonate containing systems.

Accepted Answer

A)  Temperature, stress 
B)  Tensile stress, corrosion 
C)  Corrosion, velocity 
D)  Tensile stress, velocity

Question 18

The accepted way to test for temper embrittlement is ________.

Accepted Answer

A)  Impact testing 
B)  Metallographic 
C)  RT 
D)  UT Shear wave

Question 19

Susceptibility of an alloy to sulfidation is determined by its ability to form protective _________.

Accepted Answer

A)  Oxide scales 
B)  Sulfide scales 
C)  Carbide scales 
D)  None of the above

Question 20

_________ is the sudden rapid fracture under stress (residual or applied) where the material exhibits little or no evidence of ductility or plastic deformation.

Accepted Answer

A)  Thermal fatigue 
B)  Thermal shock 
C)  Brittle fracture 
D)  Stress fracture

Exam 1: Corrosion and Materials