CWB WELDING INSPECTOR CORE EXAMS SET QUESTIONS
AND ANSWERS 2025/2026
✔✔A Wide solidification range and rapid growth rate during solidification will encourage:
(a) planar growth.
(b) equilibrium conditions.
(c) no constitutional supercooling.
(d) dendritic growth.
(e) eutectic formation. - ✔✔(d)
✔✔Centerline hot cracking im more likely with:
(a) shallow, round welds.
(b) short weld pools.
(c) wide groove angles.
(d) deep, narrow welds.
(e) vertical welds. - ✔✔(d)
✔✔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. - ✔✔(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. - ✔✔(c)
✔✔ Which of the following metals has the highest thermal conductivity?
(a) carbon steel
(b) stainless steel
(c) aluminum - ✔✔(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. - ✔✔(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. - ✔✔True
, ✔✔Electricity can be conducted by:
(a) atoms and electrons.
(b) electrons and ions.
(c) only ions. - ✔✔(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 - ✔✔(b)
✔✔Thoria is added to tunsten electrodes for what purpose? - ✔✔To increase thermionic
emission by lowering the work function.
✔✔True or False?
All pure metals have the same crystal structure. - ✔✔False. Metals generally have one
of three basic structures.
✔✔Which crystal structure(s) is (are) composed of close-packed planes? - ✔✔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. - ✔✔(c)
✔✔Multiplication and subsequent congestion of moving dislocations causes:
(a) elastic extension.
(b) work or strain hardening.
(c) a drop in the yield stress. - ✔✔(b)
✔✔Which of the following elements are most likely to form interstitial solid solutions?
(a) copper
(b) nickel
(c) carbon - ✔✔(c)
✔✔If FCC iron has a denser structure than BCC iron, why does it have a higher
solubility for carbon? - ✔✔The preferred site for carbon in BCC iron is smaller than that
in FCC iron.
✔✔If two metals have complete mutual solid solubility how many phases are formed in
the solid- one or two? - ✔✔One
AND ANSWERS 2025/2026
✔✔A Wide solidification range and rapid growth rate during solidification will encourage:
(a) planar growth.
(b) equilibrium conditions.
(c) no constitutional supercooling.
(d) dendritic growth.
(e) eutectic formation. - ✔✔(d)
✔✔Centerline hot cracking im more likely with:
(a) shallow, round welds.
(b) short weld pools.
(c) wide groove angles.
(d) deep, narrow welds.
(e) vertical welds. - ✔✔(d)
✔✔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. - ✔✔(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. - ✔✔(c)
✔✔ Which of the following metals has the highest thermal conductivity?
(a) carbon steel
(b) stainless steel
(c) aluminum - ✔✔(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. - ✔✔(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. - ✔✔True
, ✔✔Electricity can be conducted by:
(a) atoms and electrons.
(b) electrons and ions.
(c) only ions. - ✔✔(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 - ✔✔(b)
✔✔Thoria is added to tunsten electrodes for what purpose? - ✔✔To increase thermionic
emission by lowering the work function.
✔✔True or False?
All pure metals have the same crystal structure. - ✔✔False. Metals generally have one
of three basic structures.
✔✔Which crystal structure(s) is (are) composed of close-packed planes? - ✔✔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. - ✔✔(c)
✔✔Multiplication and subsequent congestion of moving dislocations causes:
(a) elastic extension.
(b) work or strain hardening.
(c) a drop in the yield stress. - ✔✔(b)
✔✔Which of the following elements are most likely to form interstitial solid solutions?
(a) copper
(b) nickel
(c) carbon - ✔✔(c)
✔✔If FCC iron has a denser structure than BCC iron, why does it have a higher
solubility for carbon? - ✔✔The preferred site for carbon in BCC iron is smaller than that
in FCC iron.
✔✔If two metals have complete mutual solid solubility how many phases are formed in
the solid- one or two? - ✔✔One
