CWB Level 3 Module 20 Practice questions
Questions with 100% Correct Answers
Which of the following metals has the highest thermal
conductivity? C
(a) carbon steel
(b) stainless steel (
(c) aluminum Correct Answer: (c) aluminum
The Ellingham diagram C
(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. Correct Answer: (b) shows the free energy
of oxide formation against temperature.
True or False?
,A metal with a high negative free energy of oxide
formation will generally require
greater shielding from the atmosphere during welding.
Correct Answer: True
Electricity can be conducted by:
(a) atoms and electrons.
(b) electrons and ions. C
(c) only ions. Correct Answer: (b) electrons and ions. C
Which of the following elements is often present in
submerged arc fluxes to improve arc
stability?
(a) copper (
(b) potassium (
(c) nickel C
(d) tungsten Correct Answer: (b) potassium (
, Thoria is added to tungsten electrodes for what
purpose? Correct Answer: To increase thermionic
emission by lowering the work function.
True or False?
All pure metals have the same crystal structure. Correct
Answer: False. Metals generally have one of three basic
structures.
Which crystal structure(s) is (are) composed of close-
packed planes? Correct 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. Correct
Answer: (c) the presence of dislocations facilitates slip.
Questions with 100% Correct Answers
Which of the following metals has the highest thermal
conductivity? C
(a) carbon steel
(b) stainless steel (
(c) aluminum Correct Answer: (c) aluminum
The Ellingham diagram C
(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. Correct Answer: (b) shows the free energy
of oxide formation against temperature.
True or False?
,A metal with a high negative free energy of oxide
formation will generally require
greater shielding from the atmosphere during welding.
Correct Answer: True
Electricity can be conducted by:
(a) atoms and electrons.
(b) electrons and ions. C
(c) only ions. Correct Answer: (b) electrons and ions. C
Which of the following elements is often present in
submerged arc fluxes to improve arc
stability?
(a) copper (
(b) potassium (
(c) nickel C
(d) tungsten Correct Answer: (b) potassium (
, Thoria is added to tungsten electrodes for what
purpose? Correct Answer: To increase thermionic
emission by lowering the work function.
True or False?
All pure metals have the same crystal structure. Correct
Answer: False. Metals generally have one of three basic
structures.
Which crystal structure(s) is (are) composed of close-
packed planes? Correct 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. Correct
Answer: (c) the presence of dislocations facilitates slip.
