Verified Solutions.
Metalworking processes in which the workpiece is subjected to plastic deformation under forces
applied through various dies and tooling correct answers Bulk Deformation Processes
Bulk Deformation Processes:
Generally classified by type of ___:
• Primary working (___)
• Secondary working (___)
• Hot, warm, cold (___) •
___, ___, ___ important design considerations
Used to make discrete parts under ___ stresses, dates back to ___ B.C. (ex: sword making)
correct answers operation
cast ingot to wrought
finished products
T/Tm
stresses, strains, strain rates
compressive, 5000
____________: (Type of Bulk Deformation)
• Operations that involve taking a solid piece of metal (generally from a cast state) and breaking
it down successively into wrought materials of various shapes
Done by the processes of ___, ___, ___, and ___
___ properties (mechanical) generally better than cast correct answers primary working
forging, rolling, extrusion, drawing
forged
__________: (Type of Bulk Deformation)
,Operations that involve further processing of the products from primary working into final or
semifinal products, such as bolts, gears, and sheet-metal parts correct answers secondary
working
In ___, parts have relatively small surface-area-to volume (or to thickness) ratio - distinction to
sheet metal.
Examples:
• ___
• ___
• ___ correct answers bulk deformation
hand tools
shafts
turbine disks
____________:
• A family of processes to make discrete parts in which plastic deformation takes place by
compressive forces applied through various dies and tooling
• One of the oldest metalworking operations known
• Dates back to ___ B.C.
• Can be carried out at room temperature ( ___ ) or elevated temperatures ( ___ or ___)
• Open ___/Closed ___ correct answers Forging
5000
cold working
warm, hot forging
die
_________________:
Caused by friction
• Can be minimized by applying an effective lubricant or ultrasonic vibrations of the platens
Double ___ can occur:
• In slender specimens with high ratios of ___ to cross-sectional area
,• When friction at the die-work piece interface is very ___ correct answers Barreling
barreling
height
high
Types of forging (5 items) correct answers Impression Die
Precision
Closed die
Isothermal
Incremental
_________:
Workpiece acquires the shape of the die cavity while it is being deformed by the closing dies
• The formation of a flash ( ___ ) must be cut off
• ___ range between 0.5% and 1% ±
• ___ depends on blank preparation, die surface finish, wear, lubricant
• ___ is an important property in accounting for die geometry correct answers impression die
forging
excess material
tolerances
surface finish
flash
The part formed is close to the final desired dimensions by using special dies made to a higher
accuracy correct answers precision forging
No flash (excess material) is formed and the workpiece is completely surrounded by the dies
correct answers closed die forging
Dies are heated to the same temperature as the hot blank. Cooling is eliminated. correct answers
Isothermal Forging
Blank is formed in several small steps using lower forces (Archard Wear Law) correct answers
Incremental Forging
, other forging operation:
• Slug is shaped in a completely closed cavity to produce fine details
• May or may not have flash correct answers Coining
other forging operation:
Typically performed at the end of a rod to produce a shape with a larger cross section correct
answers Heading
other forging operation:
Punch indents the work piece surface to produce a cavity or impression with a specific shape
correct answers Piercing
other forging operation:
Cross sectional area of a bar is reduced and altered into a shape by passing it through a pair or
sets of grooved rolls of various shapes correct answers Roll Forging
other forging operation:
hardened punch more shallow than piercing correct answers Hubbing (cold-working)
other forging operation:
reduction in thickness by die compression correct answers Cogging (drawing out)
other forging operation:
material distribution in bar stock correct answers Fullering & Edging
other forging operation:
ball bearings correct answers Skew Rolling
Forging Characteristics:
Effect of ___ pressure
• Causes cracking to require higher ___ levels
Defects:
• ___ material
• ___ flow pattern