Deck 7: Fundamentals of Metal Casting

Question 1

Casting is a process in which molten metal flows into a mold where it solidifies in the shape of the mold cavity; the term casting also applies to the part that is made by this process:

Answer 1

True

Question 2

A factory that performs casting processes is called which of the following (one best answer):

A)casting plant
B)foundry
C)ingot-making plant
D)metal working plant
E)molding plant

Answer 2

foundry

Question 3

Sand casting is which of the following types of casting process:

A)expendable mold
B)permanent mold

Answer 3

expendable mold

Question 4

The upper half of a sand-casting mold is called which one of the following:

A)cope
B)drag
C)flask
D)pattern

Question 5

In casting, a flask is which one of the following:

A)beverage bottle for workers who perform casting
B)box which holds the cope and drag
C)container for holding liquid metal
D)metal which extrudes between the mold halves

Question 6

The pattern that determines the geometry of the casting in expendable mold processes is usually made

A)oversized
B)the same size
C)undersized relative to the dimensions of the casting

Question 7

In casting processes, a runner is which one of the following:

A)channel in the mold leading from the downsprue to the main mold cavity
B)worker who moves the molten metal to the mold
C)vertical channel into which molten metal is poured into the mold

Question 8

The internal surfaces of a casting are determined during the casting process by means of which one of the following:

A)core
B)gating system
C)parting line
D)pattern
E)sprue

Question 9

Heating a metal from room temperature to pouring temperature in a casting operation depends on all of the following properties except which one:

A)density
B)heat of fusion
C)melting temperature
D)specific heat
E)thermal expansion

Question 10

Turbulence during pouring of the molten metal is undesirable for which of the following reasons (two best answers):

A)it causes discoloration of the mold surfaces
B)it dissolves the binder used to hold together the sand mold
C)it increases erosion of the mold surfaces
D)it increases the formation of metallic oxides that can become entrapped during solidification
E)it increases the mold filling time
F)it increases total solidification time

Question 11

Two important relationships that determine the flow of molten metal in casting are which of the following (two correct answers):

A)Bernoulli's theorem
B)Chvorinov's rule
C)continuity law
D)flow curve
E)Hooke's law
F)Ohm's law

Question 12

Total solidification time is defined as which one of the following:

A)time between pouring and complete solidification
B)time between pouring and cooling to room temperature
C)time between solidification and cooling to room temperature
D)time to give up the heat of fusion

Question 13

During solidification of an alloy when a mixture of solid and liquid metals is present, the solid-liquid mixture is referred to as which one of the following:

A)eutectic composition
B)ingot segregation
C)liquidus
D)mushy zone
E)solidus

Question 14

The empirical relationship that determines total solidification time in casting is known as which one of the following:

A)Bernoulli's theorem
B)Chvorinov's rule
C)continuity law
D)flow curve
E)Hooke's law
F)Ohm's law

Question 15

According to the empirical relationship in the previous question, total solidification time is proportional to which one of the following quantities:

A)(A/V)ⁿ
B)H_f
C)T_m
D)V
E)V/A
F)(V/A)²; where A = surface area of casting H_f = heat of fusion T_m = melting temperature and V = volume of casting

Question 16

Solidification shrinkage in casting is defined as which one of the following:

A)liquid contraction during cooling prior to solidification
B)liquid contraction during cooling and solidification
C)contraction during the phase change from liquid to solid
D)thermal contraction of the solidified casting during cooling to room temperature.

Question 17

Metal inserts in the walls of a sand mold cavity designed to remove heat from the molten metal more rapidly than the surrounding sand are called which one of the following:

A)external chills
B)internal chills
C)pipes
D)sprues

Question 18

A riser in casting is described by which of the following (three correct answers):

A)an insert in the casting that inhibits buoyancy of the core
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
E)waste metal that is usually recycled

Question 19

In a sand-casting mold, the V/A ratio of the riser should be

A)equal to
B)greater than
C)smaller than the V/A ratio of the casting itself

Question 20

Which of the following riser types are completely enclosed within the sand mold and connected to the main cavity by a channel to feed the molten metal (two correct answers):

A)blind riser
B)open riser
C)side riser
D)top riser