Flashcards in Chapter 10 Deck (20):
A large casting that is simple in shape and intended for subsequent reshaping by processes such as rolling or forging; usually associated with the primary metals industries.
A factory equipped for making molds, melting and handling metal in molten form, performing the casting process, and cleaning the finished casting.
Define: Open vs Closed Mold
Open: Mold in which the liquid metal is simply poured until it fills up the cavity.
Closed: Mold in which a passageway, called the gating system, is provided to permit the molten metal to flow from outside the mold into the cavity.
Define: Expendable vs. Permanent Mold
Expendable: Mold that must be destroyed in order to remove the casting once the molten metal solidifies; Usually made of sand, plaster, or similar materials
Permanent: One that can be used repeatedly to produce many castings; usually made of metal that can withstand high temperatures of the casting operation.
The upper half of the mold, typically found in a sand-casting mold
The lower/bottom half of the mold, typically found in a sand-casting mold
In expendable mold processes, the mold cavity which is made of wood, metal, plastic or other material and has the shape of the part to be cast. The mold (sand) is packed around the pattern.
Where there are internal surfaces in a casting, a core is placed inside the mold cavity to define its interior geometry; usually made of sand.
A channel or network of channels, by which molten metal flows into the cavity from outside the mold.
A channel that allows for molten metal to flow into the the cavity from outside the mold; sometimes just called the "sprue"
Horizontal channels within the mold that take the molten metal from the sprue and spread it into the main cavity.
Where shrinkage is significant in a casting, a riser is a reservoir in the mold that serves as a source of liquid metal for the casting to compensate for shrinkage during solidification.
This is the temperature difference between the temperature at pouring and the temperature at which freezing begins.
A characteristic of a molten metal that measures its capability of flowing into and filling the mold before freezing. It is the inverse of viscosity.
Define: Heat of Fusion
The amount of heat required to solidify the metal from the liquid state. A higher heat of fusion tends to increase the measured fluidity
Since alloys freeze over a temperature range, this is the temperature in which freezing begins to occur in an alloy (top line on phase diagram)
Since alloys freeze over a temperature range, this is the temperature in which all of an alloy is a solid. (below Liquidus line on phase diagram)
Due to the fact that certain regions of the casting freeze before others, certain components of an alloy may be more dense in certain areas and deprived in others. Thus, segregation in cross section of casting.
Define: Shrinkage Allowance
The amount in which the mold must be larger relative to the final casting size due to solidification shrinkage.