CWB WELDING INSPECTOR LEVEL 3
EXAM QUESTIONS AND CORRECT
DETAILED ANSWERS (2026/2027)
GRADED A+
Porosity in welds due to a specific gas is more likely if the:
(a) solubility of the gas at the freezing point is much lower than at higher temperatures.
(b) solubility of the gas at the freezing point is very high.
(c) gas does not dissolve in the liquid.
(d) solubility is independent of temperature.
(e) gas has a high solubility in the solid. - ANS-(a)
Increasing the initial plate temperature (preheat):
(a) has no effect on the cooling rate.
(b) reduces the weld heat input.
(c) reduces the cooling rate.
(d) causes narrower isotherms.
(e) improves the arc efficiency. - ANS-(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. - ANS-(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. - ANS-True
Electricity can be conducted by:
(a) atoms and electrons.
(b) electrons and ions.
(c) only ions. - ANS-(b)
Which of the following metals has the highest thermal conductivity?
(a) carbon steel
(b) stainless steel
(c) aluminum - ANS-(c)
Which of the following elements is often present in submerged arc fluxes to improve arc
stability?
(a) copper
(b) potassium
(c) nickel
(d) tungsten - ANS-(b)
Thoria is added to tunsten electrodes for what purpose? - ANS-To increase thermionic emission
by lowering the work function.
True or False?
All pure metals have the same crystal structure. - ANS-False. Metals generally have one of
three basic structures.
EXAM QUESTIONS AND CORRECT
DETAILED ANSWERS (2026/2027)
GRADED A+
Porosity in welds due to a specific gas is more likely if the:
(a) solubility of the gas at the freezing point is much lower than at higher temperatures.
(b) solubility of the gas at the freezing point is very high.
(c) gas does not dissolve in the liquid.
(d) solubility is independent of temperature.
(e) gas has a high solubility in the solid. - ANS-(a)
Increasing the initial plate temperature (preheat):
(a) has no effect on the cooling rate.
(b) reduces the weld heat input.
(c) reduces the cooling rate.
(d) causes narrower isotherms.
(e) improves the arc efficiency. - ANS-(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. - ANS-(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. - ANS-True
Electricity can be conducted by:
(a) atoms and electrons.
(b) electrons and ions.
(c) only ions. - ANS-(b)
Which of the following metals has the highest thermal conductivity?
(a) carbon steel
(b) stainless steel
(c) aluminum - ANS-(c)
Which of the following elements is often present in submerged arc fluxes to improve arc
stability?
(a) copper
(b) potassium
(c) nickel
(d) tungsten - ANS-(b)
Thoria is added to tunsten electrodes for what purpose? - ANS-To increase thermionic emission
by lowering the work function.
True or False?
All pure metals have the same crystal structure. - ANS-False. Metals generally have one of
three basic structures.
