Bulk Deformation

Question 1

Plastic deformation

Answer 1

Occurs between yield stress (Y) and ultimate tensile strength, area of permanent deformation before cracking starts

Question 2

Cold forming

Answer 2

Room temp
Good surface finish
Strain hardening = better strength

Question 3

Warm forming

Answer 3

Between room temp & recrystallization temp

Question 4

Hot forming

Answer 4

Above recrystallization temp
Isotropic
For brittle metals

Question 5

Isotropic properties

Answer 5

Properties that are uniform in all directions

Question 6

Open die forging

Answer 6

Work is compressed between two dies

Question 7

Impression die forging

Answer 7

Material squished between dies in the inverse shape of the part

Question 8

Isothermal/hot die forging

Answer 8

Dies are heated to recrystallization temps
Low flow stress allows easy material flow into cavities

Question 9

Heading

Answer 9

Used to form heads on rods, pressure provided by a punch at the end of the rod

Question 10

Piercing

Answer 10

Punches a shaped indent into piece

Question 11

Cogging/drawing out

Answer 11

Bar fed through converging dies to reduce thickness

Question 12

Fullering

Answer 12

Distributes material away from a certain area

Question 13

Edging

Answer 13

Gathers material into a certain area

Question 14

Roll forming

Answer 14

Material is fed through grooved rollers

Question 15

Skew rolling

Answer 15

Forms ball bearings using offset corkscrew rollers

Question 16

Rolling

Answer 16

Compressive forces are used to reduce the thickness of a lone workpiece

Question 17

Hot rolling

Answer 17

Recrystallization when cooling with new smaller grains
Low internal stress = uniform grains
Cheaper

Question 18

Cold rolling

Answer 18

Strain hardening = stronger
Better dimensional tolerance
More expensive

Question 19

Flat rolling defects

Answer 19

Wavy edges
Zipper cracks (in middle)
Edge cracks
Alligatoring

Question 20

Ring rolling

Answer 20

A thick ring is expanded into a thinner ring with a larger diameter

Question 21

Thread and gear rolling

Answer 21

Cold forming using threaded rollers
Stronger than a machined thread

Question 22

Rotary tube piercing

Answer 22

Creates a cavity in the center of the workpiece using compression (which leads to tensile stress)

Question 23

Types of extrusion

Answer 23

Direct extrusion (piece moves towards die)
Indirect extrusion (die moves towards piece)
Hydrostatic extrusion (piece pushed with fluid pressure)
Impact extrusion (just smack it through)
Drawing (piece pulled through converging die)