36 With regard to gating systems which one of the following

With regard to gating systems, which one of the following statements is false? a) A gating ratio of 1:2.5:2.5 leads to an unpressurized mold b) A pressurized mold provides more uniform tilling of the mold cavities c) An unpressurized mold minimizes gas entrapment in the molten metal transferred to the mold cavities d) A pressurized mold typically leads to a higher yield rate in comparison to an unpressurized mold c) None of the above With regard to hot tears in a casting, which one of the following statements is false? a) Hot tears occur less frequently in castings whose chemical composition is closer to the eutectic than those who chemical composition is farther away from the eutectic b) Hot tears typically originate in the liquid-solid transition zone in regions of micro-fluid entrapment and resultant micro void formation c) I lot tears are created when softer metal near the mold interface is plastically deformed and fractured due to tensile stresses originating from the more rapidly cooling and shrinking interior of the casting d) Hot tears occur less frequently in castings in which dendrite formation is minimized at the liquid-solid interface e) None of the above

Solution

Solution 36

Answer a:A gating ratio of 1:2.5:2.5 leads to an unpressurized system –False

Solution 37

b) Hot tears typically originate in the liquid-solid transition zone in regions of micro fluid entrapment and resultant micro void formation-False