NR 571 FINAL PAPER FULL QUESTIONS
AND CORRECT ANSWERS EXPERT REVIEW
STUDY SHEET
●● Convert these temperatures - 156º C and 450º F
A. 304º F, 151º C
B. 284º F, 218º C
C. 312º F, 232º C
D. 296º F, 246º C
Answer: C. 312º F, 232º C
●● 300 Series SS is susceptible to LME when it comes in contact with
molten ________.
A. Cadmium
B. Mercury
C. Zinc
D. Lead
Answer: C. Zinc
●● The creep threshold temperature for 1 ¼, 2 ¼, 5 and 9 Cr is
________.
A. 600º F
,B. 700º F
C. 800º F
D. 1000º F
Answer: C. 800º F
●● Thermal fatigue damage is in the form of cracking that may occur
anywhere in a metallic component where relative movement is
constrained, particularly under repeated__________.
A. Cyclic stresses
B. Thermal cycling
C. Pressure variations
D. All of the above
Answer: B. Thermal cycling
Thermal fatigue damage occurs due to repeated thermal cycling, where a
component is subjected to fluctuations in temperature. These
temperature changes cause the material to expand and contract, leading
to cyclic stresses within the material. As the material undergoes these
repeated cycles of expansion and contraction, it experiences fatigue,
which can eventually lead to cracking. This phenomenon is particularly
prevalent in areas where relative movement is constrained, such as weld
joints or areas with geometric constraints, exacerbating the development
of cracks over time. Therefore, thermal cycling is the primary factor
contributing to thermal fatigue damage in metallic components.
,●● With sour water corrosion, at a given pressure, the H2S
concentration in the sour water_________ as temperatures ________.
A. Increases, increases
B. Decreases, decreases
C. Increases, decreases
D. Decreases, increases
Answer: D. Decreases, increases
●● Mitigation of CUI is best achieved by _________.
A. A properly documented inspection program
B. A properly installed insulation system
C. A properly applied coating system
D. A properly documented NDE program
Answer: C. A properly applied coating system
Since most construction materials used in refining are susceptible to CUI
damage, mitigation is best achieved by applying an appropriate coating
to the equipment prior to insulating.
High-quality, immersion-resistant nonmetallic coatings, properly applied
to the surfaces to be insulated, can provide long-term protection.
, Flame-sprayed aluminum coatings have been used on carbon steels. The
coating corrodes preferentially by galvanic action, thereby protecting the
base metal.
●● Carburization can be confirmed by a substantial increase in hardness
and a _______ in ductility.
A. Loss
B. Gain
C. Change
D. None of the above
Answer: A. Loss
Carburization is a process where carbon atoms diffuse into the surface of
a metal at elevated temperatures, forming carbides. This can lead to an
increase in hardness of the affected material due to the formation of
these carbides. However, carburization typically results in a loss of
ductility, as the diffusion of carbon atoms into the metal lattice can
disrupt its structure and reduce its ability to deform plastically before
fracturing.
●● Which of the following materials are subject to mechanical fatigue?
A. Carbon steels
B. Stainless steels
C. Low alloy steels
AND CORRECT ANSWERS EXPERT REVIEW
STUDY SHEET
●● Convert these temperatures - 156º C and 450º F
A. 304º F, 151º C
B. 284º F, 218º C
C. 312º F, 232º C
D. 296º F, 246º C
Answer: C. 312º F, 232º C
●● 300 Series SS is susceptible to LME when it comes in contact with
molten ________.
A. Cadmium
B. Mercury
C. Zinc
D. Lead
Answer: C. Zinc
●● The creep threshold temperature for 1 ¼, 2 ¼, 5 and 9 Cr is
________.
A. 600º F
,B. 700º F
C. 800º F
D. 1000º F
Answer: C. 800º F
●● Thermal fatigue damage is in the form of cracking that may occur
anywhere in a metallic component where relative movement is
constrained, particularly under repeated__________.
A. Cyclic stresses
B. Thermal cycling
C. Pressure variations
D. All of the above
Answer: B. Thermal cycling
Thermal fatigue damage occurs due to repeated thermal cycling, where a
component is subjected to fluctuations in temperature. These
temperature changes cause the material to expand and contract, leading
to cyclic stresses within the material. As the material undergoes these
repeated cycles of expansion and contraction, it experiences fatigue,
which can eventually lead to cracking. This phenomenon is particularly
prevalent in areas where relative movement is constrained, such as weld
joints or areas with geometric constraints, exacerbating the development
of cracks over time. Therefore, thermal cycling is the primary factor
contributing to thermal fatigue damage in metallic components.
,●● With sour water corrosion, at a given pressure, the H2S
concentration in the sour water_________ as temperatures ________.
A. Increases, increases
B. Decreases, decreases
C. Increases, decreases
D. Decreases, increases
Answer: D. Decreases, increases
●● Mitigation of CUI is best achieved by _________.
A. A properly documented inspection program
B. A properly installed insulation system
C. A properly applied coating system
D. A properly documented NDE program
Answer: C. A properly applied coating system
Since most construction materials used in refining are susceptible to CUI
damage, mitigation is best achieved by applying an appropriate coating
to the equipment prior to insulating.
High-quality, immersion-resistant nonmetallic coatings, properly applied
to the surfaces to be insulated, can provide long-term protection.
, Flame-sprayed aluminum coatings have been used on carbon steels. The
coating corrodes preferentially by galvanic action, thereby protecting the
base metal.
●● Carburization can be confirmed by a substantial increase in hardness
and a _______ in ductility.
A. Loss
B. Gain
C. Change
D. None of the above
Answer: A. Loss
Carburization is a process where carbon atoms diffuse into the surface of
a metal at elevated temperatures, forming carbides. This can lead to an
increase in hardness of the affected material due to the formation of
these carbides. However, carburization typically results in a loss of
ductility, as the diffusion of carbon atoms into the metal lattice can
disrupt its structure and reduce its ability to deform plastically before
fracturing.
●● Which of the following materials are subject to mechanical fatigue?
A. Carbon steels
B. Stainless steels
C. Low alloy steels
