CH.10
A closed mold has a cavity that is entirely closed by the mold, with a passageway which is called gating system leading from the outside to the cavity. TRUE or FALSE
true
Chvorinov's rule in casting is TST = Cm (V/A)^n, in which n is usually 2. TRUE or FALSE
true
Permanent mold processes are more economic in mass production operations. TRUE or FALSE
true
Porosity and environmental problems are limitations of casting. TRUE or FALSE
true
The factory that performs casting operations is usually called a foundry. TRUE or FALSE
true
The pattern determines the external shape of the geometry where as core determines internal geometry. TRUE or FALSE
true
The two basic mold types that distinguish casting processes are "expendable mold casting" and "permanent mold casting". TRUE or FALSE
true
Chvorinov's rule states that total solidification time is proportional to which one of the following quantities: where A = surface area of casting, Hf = heat of fusion, Tm = melting temperature, and V = volume of casting? A) (A/V)^n B) heat of fusion C) melting point D) V/A E) (V/A)^n
(V/A)^n
In casting, a flask is which one of the following? A) beverage bottle for foundrymen B) box which holds the cope and drag C) container for holding liquid metal D) metal which extrudes between the mold halves
box which holds the cope and drag
In foundry work, a runner is which one of the following: A) vertical channel into which molten metal is poured into the mold B) foundryman who moves the molten metal to the mold C) channel in the mold leading from the downsprue to the main mold cavity
channel in the mold leading from the downsprue to the main mold cavity
The upper half of a sand casting mold is called which of the following? A) cope B) drag
cope
Sand casting is which of the following types? A) expendable mold B) permanent mold
expendable mold
An open mold is not open to the atmosphere at the top. TRUE or FALSE
false
Heat of fusion is the amount of heat energy required to transform the metal from liquid state to solid state. TRUE or FALSE
false
Injection molding is a sand casting process. TRUE or FALSE
false
Making complex part geometries is NOT possible in casting process. TRUE or FALSE
false
According to Chvorinov's rule, it is desirable for regions of the casting most distant from the liquid metal supply to freeze ____________ A) first B) last
first
Which one is NOT the definition of a riser in casting? A) waste metal that is usually recycled B) gating system in which the sprue feeds directly into the cavity C) metal that is not part of the casting D) source of molten metal to feed the casting and compensate for shrinkage during solidification
gating system in which the sprue feeds directly into the cavity
In a sand casting mold, the V/A ratio of the riser should be _________________ the V/A ratio of the casting itself. A) equal o B) greater than C) smaller than
greater than
Total solidification time is defined as which one of the following? A) time between pouring and cooling to room temperature B) time between pouring and complete solidification C) time between solidification and cooling to room temperature
time between pouring and complete solidification
