Casting

Question 1

Casting

Answer 1

Pouring molten metal into a mold cavity to form into desired shape

Question 2

Pouring basin

Answer 2

The hole the molten metal gets poured into

Question 3

Sprue funnel

Answer 3

Tapered channel that brings metal into well

Question 4

Gating system

Answer 4

Traps contaminants, reduces turbulence, prevents premature cooling, and helps avoid gas entrapment

Question 5

Dross/slag

Answer 5

Oxidized metal that has reacted with air and other gases

Question 6

Which part of a mold cools first?

Answer 6

The walls, it’ll cool from the outside inwards

Question 7

When does most shrinkage occur?

Answer 7

During phase changes

Question 8

Continuous casting

Answer 8

Molten metal is extruded into a continuous bar

Question 9

Disposable mold types

Answer 9

Sand casting
Shell mold casting
Polystyrene casting
Investment casting
Plaster/ceramic mold casting

Question 10

Types of cast patterns

Answer 10

One piece
Split (cavity formed by 2 sides)
Match plate (contains multiple splits)

Question 11

Die casting

Answer 11

Molten metal is injected into mold cavity at high pressure

Question 12

Low-pressure casting

Answer 12

Molten metal is forced into mold cavity at low pressure that is maintained until it solidifies

Question 13

Centrifugal casting

Answer 13

Molten metal is distributed into cavities by centrifugal forces, primarily used for long, cylindrical parts

Question 14

Slush casting

Answer 14

Hollow cast created by pouring liquid metal out after outside has partially solidified

Question 15

Squeeze casting

Answer 15

Combines casting and forging, molten metal is poured into preheated dies that are then clamped shut

Question 16

Hot chamber casting

Answer 16

Molten metal is forced into cavity with piston, allows fast cycle times (esp with low melting point metals)

Question 17

Cold chamber casting

Answer 17

Done at higher pressures than hot chamber casting, used for higher melting point metals

Question 18

Slow cooling rates result in…

Answer 18

coarse dendritic structures

Question 19

High cooling rates result in…

Answer 19

finer structures with less spaces between dendrite arms

Question 20

When grain size decreases…

Answer 20

Strength, ductility, and chances of cracks increase
Microporosity decreases

Question 21

Anisotropic properties

Answer 21

Properties that aren’t uniform across a material

Question 22

Casting defects

Answer 22

Flash
Cavities
Cracks & hot tears
Cold shut
Defective surface
Misrun
Inclusions

Question 23

Flash

Answer 23

Extra material that swells out

Question 24

Hot tears

Answer 24

Caused by metal being constrained from shrinking freely

Question 25

Cold shut

Answer 25

Part doesn't fully fuse because of premature solidification

Question 26

Misrun

Answer 26

Not enough metal results in an incomplete cast

Question 27

Mold design considerations

Answer 27

Avoid sharp corners and large radii Uniform thickness required Use ribs to reduce warping

Question 28

Disposable casting costs ___ and is better for a ___ number of parts. Permanent casting costs ___ and is better for a ___ number of parts.

Answer 28

less; lower more; higher