UT2

Question 1

A manufacturing process based on plastic flow is:
A) welding
B) casting
C) forging
D) all of the above

Answer 1

C) FORGING

Question 2

Describe plastic flow:

Answer 2

Deformation of a material that remains rigid under stresses of less than a certain intensity but behaves under severe stresses

Question 3

A definite break in a material caused by excessive working of the metal during this forging, rolling or extruding operation:
A) cold shut
B) seam
C) burst
D) hot tear

Answer 3

C) BURST

Question 4

An inherent defect formed PRIOR TO COMPLETION OF SOLIDIFICATION of the casting because of restricted contraction is called a:
A) hot tear
B) shrinkage
C) burst
D) cold shut

Answer 4

À) HOT TEAR

Question 5

An advantage of investment casting over green sand casting is:
A) reusable mold
B) larger parts may be cast
C) more complex shapes may be used
D) the need for cores never arises

Answer 5

C) more COMPLEX SHAPES

Question 6

A green sand mold is:
A) a sand mold coated with a ‘green’ wash
B) a sand mold mixture made up of sand, clay and water
C) a sand mold not yet ready for casting
D) a sand mold used in the production of cores only

Answer 6

B) a sand mold mixture made up of sand, clay and water

Question 7

In which of the following casting processes are cores never used:
A) a shell mold casting
B) investment casting
C) permanent mold casting
D) none of the above

Answer 7

D) NONE of the above

Question 8

An inherent defect formed during the plastic stage of solidification is:
A) burst
B) shrinkage
C) cold shut
D) hot tear

Answer 8

D) HOT TEAR

Question 9

In gas welding, the acetylene is usually burned with:
A) oxygen
B) hydrogen
C) argon
D) nitrogen

Answer 9

À) oxygen

Question 10

When are copper electrodes used in welding?

Answer 10

Spot/Seam welding

Question 11

A difference between shielded metal-arc welding and gas metal-arc welding is that in gas metal arc welding:

A) the electrode is consumable
B) the shielding gas is contained in the flux covering the electrode
C) a stream of protective gas is passed through an inverted cup or a nozzle which surrounds the electrode
D) a slag coating is formed to protect the weld as it cools

Answer 11

C) a stream of protective gas is passed through an inverted cup or a nozzle which surrounds the electrode

Question 12

A non-consumable electrode used for arc welding would be made of:
A) tungsten
B) steel
C) copper
D) any of the above

Answer 12

À) tungsten

Question 13

Another term for investment casting is the:
A) die casting method
B) lost wax process
C) semi-centrifugal process
D) none of the above

Answer 13

B) lost wax process

Question 14

A metal forming operational which allows three-dimensional control over the shape of the product is:
A) rolling
B) extruding
C) forging
D) all of the above

Answer 14

C) forging

Question 15

What is the sprues position of a mold?

Answer 15

Vertical runner

Question 16

List the following in order from top to bottom on a mold:
A) Cheeks
B) Cope
C) Drag

Answer 16

Cope - cheeks - drag

Question 17

Which of the following results from inclusions in the original cast material which are flattened out in the direction of rolling, forging, extruding?
A) laminations
B) stringers
C) blow holes
D) laps

Answer 17

B) STRINGERS

Question 18

What is an amorphous solid?

Answer 18

Solidified but doesn’t take crystalline structure, more like a very viscous liquid.

Question 19

Crystalline solids have a specific crystal structure called a ‘lattice’. What are the 3 main lattice structures?

Answer 19

1. Body centered cubic (BCC)
2. Face centered cubic (FCC)
3. Hexagonal closed packed (HCP)

Question 20

Metals that are body centered cubic have what two important properties?
Give two examples.

Answer 20

Hard and strong.
Ex. Iron, tungsten

Question 21

What is the main property of a metal that solidified with a face centered cubic?
Give 3 examples.

Answer 21

Ductile.
Ex. Aluminum, copper, lead

Question 22

Metals that solidify under hexagonal closed packed lattice structure are susceptible to what?
Give 2 examples.

Answer 22

Work hardening.
Ex. Zinc, magnesium

Question 23

What is tensile strength?

Answer 23

The max stress that can be applied by pulling or stretching the material prior to fracture

Question 24

What is yield strength?

Answer 24

The ability of a material that is deformed to return to original shape once load is removed

Question 25

Define hardness:

Answer 25

The ability of a material to resist deformation when a compressive force is applied

Question 26

Define toughness:

Answer 26

The ability of a material to deform plastically without fracture

Question 27

What is fatigue strength?

Answer 27

À materials ability to undergo cyclic stresses without failure