Rolling and Forging Manufacturing Processes. Outline TemperatureRolling Flat Rolling Shape Rolling Operations Thread Rolling Seamless Tubing and Pipe.

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





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



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


Example of a polyester-reinforced rubber sheet with fibers exposed



Example of a steel-belted rubber sheet with the belt exposed


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


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




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



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




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


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

Rolling and Forging Manufacturing Processes. Outline TemperatureRolling Flat Rolling Shape Rolling Operations Thread Rolling Seamless Tubing and Pipe.

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