Rolling and Rolling and Forging Forging Manufacturing Manufacturing Processes Processes
Rolling and ForgingRolling and Forging
Manufacturing Manufacturing ProcessesProcesses
OutlineOutline
TemperatureTemperatureRollingRolling
Flat RollingFlat RollingShape Rolling OperationsShape Rolling OperationsThread RollingThread RollingSeamless Tubing and PipeSeamless Tubing and PipeRolling Nonmetallic MaterialsRolling Nonmetallic Materials
ForgingForgingOpen-Die ForgingOpen-Die ForgingClosed-Die ForgingClosed-Die ForgingRoll ForgingRoll ForgingHeadingHeadingRotary SwagingRotary SwagingForging MachinesForging MachinesDiesDiesEconomicsEconomics
Rolling and ForgingRolling and Forging
RollingRollingThe thickness of a slab of a The thickness of a slab of a slab or plate is reduced by slab or plate is reduced by cylindrical rolls which rotate to cylindrical rolls which rotate to pull the material between them pull the material between them and compress itand compress it
ForgingForgingA workpiece is compressed A workpiece is compressed between opposing dies so that between opposing dies so that the material is forced into the the material is forced into the die shapedie shape
Temperature in Metal Temperature in Metal FormingForming
Cold working (room temperature Cold working (room temperature or slightly higher)or slightly higher)
Warm working (30% - 50% of the Warm working (30% - 50% of the melting temperature)melting temperature)
Hot working (50% - 75% of the Hot working (50% - 75% of the melting temperature)melting temperature)
Isothermal formingIsothermal formingTools are preheated to prevent Tools are preheated to prevent surface cooling during formingsurface cooling during forming
Structure/Property Structure/Property ModificationModification
Cold WorkingCold Working
AdvantagesAdvantages- No heating requiredNo heating required- Better surface finishBetter surface finish- Better dimensional accuracyBetter dimensional accuracy- Parts are interchangeableParts are interchangeable- Better strength, fatigue and Better strength, fatigue and
wear propertieswear properties- Directional properties can be Directional properties can be
impartedimparted- Minimal contamination Minimal contamination
problemsproblems
Cold WorkingCold Working
DisadvantagesDisadvantages- Higher forces requiredHigher forces required- More powerful equipment More powerful equipment
requiredrequired- Less ductility is availableLess ductility is available- Surfaces must be cleanSurfaces must be clean- Intermediate anneals may be Intermediate anneals may be
needed to restore ductilityneeded to restore ductility- Directional properties may be Directional properties may be
detrimentaldetrimental- May produce undesirable May produce undesirable
residual stressesresidual stresses
Typical Rolled ProductsTypical Rolled Products
Typical Rolled ProductsTypical Rolled Products
Rolling ProcessRolling Process
Rolling ProcessRolling Process
Rolling ProcessRolling Process
Rolling ProcessRolling Process
Rolling ProcessRolling Process
Example of a Hot Example of a Hot Rolling LineRolling Line
Rolling DefectsRolling Defects
Shape RollingShape Rolling
Uses a series of specially shaped Uses a series of specially shaped rolls to form a beam with a specific rolls to form a beam with a specific cross section (such as an I-beam)cross section (such as an I-beam)
Ring RollingRing Rolling
Uses rolls to form a thick, small-Uses rolls to form a thick, small-diameter ring into a thin, larger-diameter ring into a thin, larger-diameter ringdiameter ring
Ring RollingRing Rolling
Thread RollingThread Rolling
Uses moving dies with grooves to Uses moving dies with grooves to form threads on cylindrical partsform threads on cylindrical parts
Thread RollingThread Rolling
Material Property Material Property ChangesChanges
Roll PiercingRoll Piercing
Uses compressive stresses on a Uses compressive stresses on a cylindrical part to cause tensile cylindrical part to cause tensile forces at the interior, creating a forces at the interior, creating a hole to form a thick-walled tubehole to form a thick-walled tube
Example of a Tube Example of a Tube Rolling MillRolling Mill
Rolling Nonmetallic Rolling Nonmetallic MaterialsMaterials
- PaperPaper- Plastic sheetsPlastic sheets- Rubber productsRubber products- Reinforced fabricReinforced fabric
CalenderingCalendering
Passes material through a Passes material through a series of gaps between rolls to series of gaps between rolls to form a thin sheetform a thin sheet
CalenderingCalendering
CalenderingCalendering
Example of a calendered rubber sheet with two layers
Courtesy Cooper Tire
Calendering of RubberCalendering of Rubber
Coated ProductsCoated Products
Reinforced MaterialsReinforced Materials
spools
reinforcing material
windup
coating material
Coating on both sides of reinforcing material
comb
coating material
Reinforced MaterialsReinforced Materials
Example of a polyester-reinforced rubber sheet with fibers exposed
Courtesy Cooper Tire
Reinforced MaterialsReinforced Materials
Example of a steel-belted rubber sheet with the belt exposed
Courtesy Cooper Tire
Calender Control Calender Control SystemsSystems
Calendering Thickness Calendering Thickness SensorsSensors
X rays or beta radiation (electrons)
Detector
Emitter
some radiation is blocked, depending on thickness
MillingMilling
Squeezes material between rolls to Squeezes material between rolls to mix or preheat it for further mix or preheat it for further processesprocesses
ForgingForging
ForgingForging
A deformation process in which A deformation process in which the material is compressed the material is compressed between dies, using impact or between dies, using impact or gradual pressure to form the gradual pressure to form the partpart
ForgingForging
Example of a Forging Example of a Forging MachineMachine
Example of a Forging Example of a Forging MachineMachine
Working TemperatureWorking Temperature
Hot ForgingHot Forging
Material is above its Material is above its recrystallization temperaturerecrystallization temperature
Cold ForgingCold Forging
Increased strength from strain Increased strength from strain hardeninghardening
ForgingForging
BilletBillet
A piece of material with a square or circular cross A piece of material with a square or circular cross section; usually produced by a deformation process section; usually produced by a deformation process such as rolling or extrusionsuch as rolling or extrusion
Open Die ForgingOpen Die Forging
Compresses the work between flat or Compresses the work between flat or nearly flat diesnearly flat dies
Open Die ForgingOpen Die Forging
Open Die ForgingOpen Die Forging
Open Die ForgingOpen Die Forging
AdvantagesAdvantages
Simple, inexpensive dies; wide Simple, inexpensive dies; wide range of sizes; good strengthrange of sizes; good strength
LimitationsLimitations
Simple shapes only; difficult to Simple shapes only; difficult to hold close tolerances; hold close tolerances; machining necessary; low machining necessary; low production rate; poor utilization production rate; poor utilization of material; high skill requiredof material; high skill required
Closed Die ForgingClosed Die Forging
Also called impression-die forging; Also called impression-die forging; compresses the material into the compresses the material into the shape of the die cavityshape of the die cavity
Closed Die ForgingClosed Die Forging
Closed Die ForgingClosed Die Forging
AdvantagesAdvantages
Good utilization of material; Good utilization of material; better properties than open die better properties than open die forging; good dimensional forging; good dimensional accuracy; high production rate; accuracy; high production rate; good reproducibilitygood reproducibility
LimitationsLimitations
High die cost for small High die cost for small quantities; machining often quantities; machining often necessarynecessary
Roll ForgingRoll Forging
Uses grooved rolls to reduce Uses grooved rolls to reduce thickness and increase length of thickness and increase length of round or flat barsround or flat bars
Roll ForgingRoll Forging
Roll ForgingRoll Forging
Roll ForgingRoll Forging
CoiningCoining
Uses dies to press fine detail into Uses dies to press fine detail into both sides of the workpieceboth sides of the workpiece
Upsetting/HeadingUpsetting/Heading
Decreases the length and increases Decreases the length and increases the diameter of the workpiece; the diameter of the workpiece; often used to form heads on nails, often used to form heads on nails, bolts, etc.bolts, etc.
Orbital ForgingOrbital Forging
Uses a die that moves in various Uses a die that moves in various directions to compress the directions to compress the workpieceworkpiece
SwagingSwaging
Uses hammering dies to decrease Uses hammering dies to decrease the diameter of the partthe diameter of the part
SwagingSwaging
Forging Dies and Die Forging Dies and Die InsertsInserts
Separate inserts may be used for Separate inserts may be used for forging complex shapes; this may forging complex shapes; this may be less expensive than a complex be less expensive than a complex single-piece diesingle-piece die
Forging DefectsForging Defects
Forging MachinesForging Machines
Forging MachinesForging Machines
Example of a Forging Example of a Forging MachineMachine
EconomicsEconomics
SummarySummary
Rolling and forging shape parts Rolling and forging shape parts by deforming the material into by deforming the material into the desired shapethe desired shape