CWB Welding Inspector Level III Study
Guide
Which of the following metals has the highest thermal conductivity?
(a) carbon steel
(b) stainless steel
(c) aluminum - Answer-(c)
The Ellingham diagram
(a) is a plot of thermal conductivity against temperature,
(b) shows the free energy of oxide formation against temperature.
(c) shows the rate of oxidation of metals against temperature. - Answer-(b)
True or False?
A metal with a high negative free energy of oxide formation will generally require greater shielding from
the atmosphere during welding. - Answer-True
Electricity can be conducted by:
(a) atoms and electrons.
(b) electrons and ions.
(c) only ions. - Answer-(b)
Which of the following elements is often present in submerged arc fluxes to improve arc stability?
(a) copper
, (b) potassium
(c) nickel
(d) tungsten - Answer-(b)
Thoria is added to tunsten electrodes for what purpose? - Answer-To increase thermionic emission by
lowering the work function.
True or False?
All pure metals have the same crystal structure. - Answer-False. Metals generally have one of three basic
structures.
Which crystal structure(s) is (are) composed of close-packed planes? - Answer-FCC and HCP
The real strength of metals is lower than the theoretical value because:
(a) real crystals always fracture along specific crystal planes.
(b) grain boundary sliding occurs.
(c) the presence of dislocations facilitates slip. - Answer-(c)
Multiplication and subsequent congestion of moving dislocations causes:
(a) elastic extension.
(b) work or strain hardening.
(c) a drop in the yield stress. - Answer-(b)
Which of the following elements are most likely to form interstitial solid solutions?
(a) copper
(b) nickel
Guide
Which of the following metals has the highest thermal conductivity?
(a) carbon steel
(b) stainless steel
(c) aluminum - Answer-(c)
The Ellingham diagram
(a) is a plot of thermal conductivity against temperature,
(b) shows the free energy of oxide formation against temperature.
(c) shows the rate of oxidation of metals against temperature. - Answer-(b)
True or False?
A metal with a high negative free energy of oxide formation will generally require greater shielding from
the atmosphere during welding. - Answer-True
Electricity can be conducted by:
(a) atoms and electrons.
(b) electrons and ions.
(c) only ions. - Answer-(b)
Which of the following elements is often present in submerged arc fluxes to improve arc stability?
(a) copper
, (b) potassium
(c) nickel
(d) tungsten - Answer-(b)
Thoria is added to tunsten electrodes for what purpose? - Answer-To increase thermionic emission by
lowering the work function.
True or False?
All pure metals have the same crystal structure. - Answer-False. Metals generally have one of three basic
structures.
Which crystal structure(s) is (are) composed of close-packed planes? - Answer-FCC and HCP
The real strength of metals is lower than the theoretical value because:
(a) real crystals always fracture along specific crystal planes.
(b) grain boundary sliding occurs.
(c) the presence of dislocations facilitates slip. - Answer-(c)
Multiplication and subsequent congestion of moving dislocations causes:
(a) elastic extension.
(b) work or strain hardening.
(c) a drop in the yield stress. - Answer-(b)
Which of the following elements are most likely to form interstitial solid solutions?
(a) copper
(b) nickel
