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 - 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 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.