Question 1

High strength, low allow steels such as A193-B7 bolts and compressor parts are susceptible to hydrogen stress cracking. A193-B7M bolts are susceptible if __________.

Accepted Answer

A)  Exposed 
B)  Overtorqued 
C)  Double nutted 
D)  None of the above

Question 2

When carbon is absorbed into a material at elevated temperatures while in contact with a carbonaceous substance it is called carburization. Temperatures usually have to be above __________ for this to occur.

Accepted Answer

A)  1000º F 
B)  1100º F 
C)  1200º F 
D)  1400º F

Question 3

300 Series SS is susceptible to LME when it comes in contact with molten ________.

Accepted Answer

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

Question 4

Erosion-corrosion is a description for the damage that occurs when corrosion contributes to erosion by removing protective films or scales, or by exposing the metal surface to further ________ under the combined action of corrosion-erosion.

Accepted Answer

A)  Stress 
B)  Corrosion 
C)  Oxidation 
D)  None of the above

Question 5

For furnaces, to prevent PASCC, keep the firebox heated above the dewpoint to keep ________ from forming.

Accepted Answer

A)  Water 
B)  Acids 
C)  Moisture 
D)  Corrosion

Question 6

Formation of a metallurgical phase known as sigma phase results in a loss of _________ in some stainless steels as a result of high temperature exposure.

Accepted Answer

A)  Ductility 
B)  Fracture toughness 
C)  Embrittlement 
D)  None of the above

Question 7

Which material below is not susceptible to caustic corrosion?

Accepted Answer

A)  Carbon steel 
B)  400 Series SS 
C)  300 Series SS 
D)  Low alloy steel

Question 8

Creep damage is found in high temperature equipment operating above the ________. Fired heater tubes and components, Catalytic reactors, FCC reactors and FCC fractionator and regenerator internals all operate in or near this.

Accepted Answer

A)  Transition range 
B)  MADT 
C)  Creep range 
D)  None of the above

Question 9

All piping and equipment exposed to HF acid at any concentration with hardness levels above ________ are subject to hydrogen stress cracking.

Accepted Answer

A)  200 BHN 
B)  210 BHN 
C)  227 BHN 
D)  237 BHN

Question 10

With chloride stress corrosion cracking, __________ temperatures ________ the susceptibility for cracking.

Accepted Answer

A)  Decreasing, Increases 
B)  Increasing, Increases 
C)  Increasing, Decreases 
D)  Decreasing, Eliminates

Question 11

SSC is a form of ________ stress corrosion cracking.

Accepted Answer

A)  Hydrogen 
B)  Caustic 
C)  Polythionic 
D)  Alkaline

Question 12

Equipment that is temper embrittled may be susceptible to _______ during start-up and shutdown.

Accepted Answer

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

Question 13

Which of the following materials is susceptible to sigma phase embrittlement?

Accepted Answer

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

Question 14

Blistering, HIC, SOHIC and SSC damage can occur wherever there is a ____________ environment.

Accepted Answer

A)  Wet H₂S 
B)  Hydrogen 
C)  Sulfur 
D)  Aqueous

Question 15

Creep and stress rupture is more likely in a _________ grained material than a _______ grained material.

Accepted Answer

A)  Course, Fine 
B)  Fine, Course 
C)  Austenitic, Martensitic 
D)  None of the above

Question 16

Cavitation is best prevented by avoiding conditions that allow the absolute pressure to fall below the ___________ of the liquid or by changing the material properties.

Accepted Answer

A)  Minimum pressure 
B)  Pressure/vapor ratio 
C)  Maximum pressure 
D)  Vapor pressure

Question 17

Corrosion of the anode may be significantly higher ________ to the connection to the cathode, depending on solution conductivity.

Accepted Answer

A)  Parallel 
B)  Adjacent 
C)  Diagonally 
D)  Perpendicular

Question 18

To prevent hydrogen embrittlement, use lower strength steels and _________ to temper the microstructure, improve ductility and reduce residual stresses.

Accepted Answer

A)  Alloys 
B)  Preheat 
C)  PWHT 
D)  All of the above

Question 19

The endurance limit is usually about:

Accepted Answer

A)  10-20% of a material's ultimate tensile strength. 
B)  40-50% of a material's ultimate tensile strength 
C)  10-20% of a material's yield strength. 
D)  40-50% of a material's yield strength. 
E)  Half way up the ladder of a 150' column (tower).

Question 20

Thermal fatigue becomes of concern if the temperature swings exceed:

Accepted Answer

A)  50 oF. 
B)  100 oF. 
C)  200 oF. 
D)  400 oF.

Exam 1: Corrosion and Materials