Chapter 10

Question 1

Define: Ingot

Answer 1

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.

Question 2

Define: Foundry

Answer 2

A factory equipped for making molds, melting and handling metal in molten form, performing the casting process, and cleaning the finished casting.

Question 3

Define: Open vs Closed Mold

Answer 3

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.

Question 4

Define: Expendable vs. Permanent Mold

Answer 4

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.

Question 5

Define: Cope

Answer 5

The upper half of the mold, typically found in a sand-casting mold

Question 6

Define: Drag

Answer 6

The lower/bottom half of the mold, typically found in a sand-casting mold

Question 7

Define: Pattern

Answer 7

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.

Question 8

Define: Core

Answer 8

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.

Question 9

Define: Gate

Answer 9

A channel or network of channels, by which molten metal flows into the cavity from outside the mold.

Question 10

Define: Downsprue

Answer 10

A channel that allows for molten metal to flow into the the cavity from outside the mold; sometimes just called the “sprue”

Question 11

Define: Runner

Answer 11

Horizontal channels within the mold that take the molten metal from the sprue and spread it into the main cavity.

Question 12

Define: Riser

Answer 12

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.

Question 13

Define: Superheat

Answer 13

This is the temperature difference between the temperature at pouring and the temperature at which freezing begins.

Question 14

Define: Fluidity

Answer 14

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.

Question 15

Define: Heat of Fusion

Answer 15

The amount of heat required to solidify the metal from the liquid state. A higher heat of fusion tends to increase the measured fluidity

Question 16

Define: Liquidus

Answer 16

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)

Question 17

Define: Solidus

Answer 17

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)

Question 18

Define: Segregation

Answer 18

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.

Question 19

Define: Shrinkage Allowance

Answer 19

The amount in which the mold must be larger relative to the final casting size due to solidification shrinkage.

Question 20

Define: Chill

Answer 20

Internal or external heat sinks that cause rapid freezing in certain regions of the casting. Usually metal parts placed inside the cavity before pouring so as to remove heat from the casting.,