ME Processing and Manufacturing

Question 1

In metal casting, porosity defects are primarily caused by:

Accepted Answer

Gas entrapment or shrinkage during solidification

Answer

Excessive mold temperature

Answer

Slow pouring rates

Answer

Low carbon content

Question 2

Hot working of metals is performed above the recrystallization temperature primarily to:

Accepted Answer

Allow dynamic recrystallization, maintaining ductility at high deformation levels

Answer

Maximize work hardening

Answer

Produce fine grain structures at low cost

Answer

Avoid oxidation

Question 3

Which powder metallurgy step bonds metal powders into a dense solid part using heat and/or pressure below the melting point?

Accepted Answer

Sintering

Answer

Compaction

Answer

Atomization

Answer

Blending

Question 4

The purpose of annealing a cold-worked metal is to:

Accepted Answer

Restore ductility by reducing dislocation density via recovery and recrystallization

Answer

Increase dislocation density

Answer

Increase hardness

Answer

Increase carbon content

Question 5

Investment casting (lost-wax casting) is preferred for complex shapes because:

Accepted Answer

It uses an expendable wax pattern to produce intricate, near-net-shape parts

Answer

It uses permanent metal molds for high volume

Answer

It is the lowest cost casting process

Answer

It requires no post-processing

Question 6

In extrusion manufacturing, the extrusion ratio is defined as:

Accepted Answer

Billet cross-sectional area divided by product cross-sectional area

Answer

Exit velocity divided by entry velocity

Answer

Force divided by billet area

Answer

Die angle in degrees