Question 1

What is the primary difference between extrusion and drawing in metal forming?

Accepted Answer

Extrusion pushes the billet through a die

Answer

Drawing is used for only non-metal materials

Answer

Drawing pulls the billet through a die

Answer

Both use pulling methods

Question 2

Which materials are commonly extruded?

Accepted Answer

Aluminum, copper, steel, and plastics

Answer

Wood and ceramics

Answer

Only hardened steels

Answer

Glass and ceramics

Question 3

What type of extrusion uses the die moving toward the billet?

Accepted Answer

Indirect extrusion

Answer

Hot extrusion

Answer

Lateral extrusion

Answer

Direct extrusion

Question 4

What is hydrostatic extrusion characterized by?

Accepted Answer

Use of a pressurized fluid around the billet

Answer

High friction

Answer

Pulling the billet through a die

Answer

Room temperature operation

Question 5

What is one advantage of hydrostatic extrusion?

Accepted Answer

Friction is low and deformation is uniform

Answer

It works best on ceramics

Answer

The billet expands rather than contracts

Answer

It uses cold temperatures

Question 6

What is the typical maximum length for extruded materials?

Accepted Answer

30 meters

Answer

50 meters

Answer

5 meters

Answer

100 meters

Question 7

What extrusion ratio (R = Ao/Af) is needed to deform material into the plastic region?

Accepted Answer

At least 4

Answer

No minimum ratio is needed

Answer

Less than 1

Answer

At least 1

Question 8

What factor does *not* affect the extrusion force?

Accepted Answer

Color of the metal

Answer

Temperature

Answer

Friction between billet and die

Answer

Billet material strength

Question 9

Why is hot extrusion used?

Accepted Answer

To reduce force for metals lacking room-temperature ductility

Answer

Because it uses less energy

Answer

To make the billet cold

Answer

To reduce tool wear

Question 10

What is a drawback of hot extrusion?

Accepted Answer

Die wear from high temperature

Answer

Needs very soft materials

Answer

Reduced ductility

Answer

Slower production

Question 11

What issue can arise from billet cooling in the chamber during hot extrusion?

Accepted Answer

Non-uniform extrusion

Answer

Extra lubrication

Answer

Excessive ductility

Answer

Increased die life

Question 12

What can be used to reduce friction caused by oxidation during hot extrusion?

Accepted Answer

Heating the billet in an inert atmosphere

Answer

Using a cold billet

Answer

Adding water cooling

Answer

Increasing extrusion speed

Question 13

What is typically used for lubrication during hot extrusion?

Accepted Answer

Molten glass

Answer

Water

Answer

Motor oil

Answer

Graphite paste

Question 14

What is the advantage of jacketing or canning during extrusion?

Accepted Answer

Prevents sticking to chamber walls

Answer

Reduces billet size

Answer

Improves strength

Answer

Increases temperature

Question 15

What is an advantage of cold extrusion?

Accepted Answer

No need to heat the billet

Answer

Reduced mechanical properties

Answer

Higher energy consumption

Answer

Better ductility than hot extrusion

Question 16

What is one disadvantage of cold extrusion?

Accepted Answer

High stress magnitudes on the tools

Answer

Difficult dimensional control

Answer

High temperature needed

Answer

Poor surface finish

Question 17

What is impact extrusion?

Accepted Answer

Cold extrusion using a punch to force material backward

Answer

Drawing process with a stripper plate

Answer

Hot extrusion using a mandrel

Answer

Hydrostatic process for soft metals

Question 18

What type of fluid is used in hydrostatic cold extrusion?

Accepted Answer

Vegetable oils

Answer

Engine oil

Answer

Air

Answer

Water

Question 19

What is an advantage of hydrostatic cold extrusion?

Accepted Answer

Brittle materials can be extruded

Answer

High temperature improves strength

Answer

Requires a large die angle

Answer

Increased wall friction improves uniformity

Question 20

What equipment is commonly used for hot extrusion?

Accepted Answer

Horizontal hydraulic presses

Answer

Cooling chambers

Answer

Vertical mechanical hammers

Answer

Manual rams

Question 21

Why is vertical hydraulic press used in cold extrusion?

Accepted Answer

Saves floor space

Answer

Reduces ductility

Answer

Increases temperature

Answer

Improves die wear

Question 22

What is the maximum reduction in cross-sectional area during drawing?

Accepted Answer

63%

Answer

90%

Answer

10%

Answer

25%

Question 23

What process reduces the size of rods or wires by pulling them through a die?

Accepted Answer

Drawing

Answer

Rolling

Answer

Extrusion

Answer

Forging

Question 24

What is a characteristic of wet drawing?

Accepted Answer

Dies and rods are immersed in lubricant

Answer

Metal is heated first

Answer

Lubricant is dry powder

Answer

No lubricant is used

Question 25

What can ultrasonic vibration in the drawing process help with?

Accepted Answer

Reduce forces and improve die life

Answer

Increase temperature

Answer

Lower ductility

Answer

Eliminate drawing speed control

Question 26

Why is annealing used between drawing passes?

Accepted Answer

To restore ductility

Answer

To reduce oxidation

Answer

To cool the die

Answer

To increase surface friction

Question 27

What is bundle drawing used for?

Accepted Answer

Drawing numerous wires at once

Answer

Extruding wide plates

Answer

Making thick rods

Answer

Annealing bundled bars

Question 28

What drawing machine is used for wires over several kilometers?

Accepted Answer

Bull block

Answer

Hydrostatic chamber

Answer

Punch press

Answer

Draw bench

Question 29

What is the draw bench best suited for?

Accepted Answer

Diameters > 20 mm and lengths < 30 m

Answer

High-volume wire spooling

Answer

Drawing soft plastics

Answer

Producing forged rods

Question 30

What does the mandrel in tube drawing help create?

Accepted Answer

Internal cavities

Answer

Oxidation resistance

Answer

Die temperature

Answer

External threads

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