CWB Welding Inspector Level III Study Guide Graded A+

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)