Problem 16 (2 pts) With regard to permanent mold casting, die casting, and sand casting, which one of the following statements is true? a) Molten metal is gravity fed into a mold in die casting b) Molten metal is injected under pressure into a mold in permanent mold casting c) Sand cores are typically used in permanent mold casting to create interior cavities within the casting d) Metal slide cores are typically used in sand casting to create interior cavities within the casting e) Sand castings typically solidify much faster within the mold than die castings Problem 17 (2 pts) Metal fluidity is critical to successive molding filling during a casting process. Which one of the following factors will not enhance metal fluidity during pouring? a) Using a metal alloy whose chemical composition is substantially different than the eutectic composition b) Heating the metal alloy well above is liquidus temperature prior to pouring c) Pouring the metal into a mold with low thermal conductivity d) Using a metal alloy with low viscosity in the molten state e) None of the above Problem 18 (2 pts) In a sand casting process, a lack of sand permeability typically leads to what type of casting defect? a) Hot tears b) Gas porosity defects c) Shrinkage voids d) Casting discoloration e) Casting Expansion Problem 19 (2 pts) The parting line on a casting corresponds to which one of the following? a) Regions in which gates and risers are removed from the casting b) A casting defect due to void formation at the casting surface c) Region defining the interface between the cope and drag d) A casting defect due to a hot tear at the casting surface e) None of the above