2. FORMING PROCESSES
BULK DEFORMATION
METAL ROLLING
• Shape Rolling
• Ring Rolling
• Thread Rolling
• Rotary Tube Piercing
METAL FORGING
• Forging Hammers
• Hydraulic And
Mechanical Presses
• Piercing
• Sizing
• Roll Forging
• Ring Forging
• Riveting
• Coining
• Isothermal Forging
• Trimming
EXTRUSION
• Extrusion Design
• Impact Extrusion
• Hydrostatic Extrusion
METAL DRAWING
SHEET METAL FORMING
• Sheet Metal Basics
• Sheet Metal Cutting
• Sheet Metal Bending
• Deep Drawing Sheet Metal
• Ironing Sheet Metal
• Metal Spinning
• Rubber Forming Of Sheet
Metal
• High Energy Rate Forming
3. FORGING
FORGING is a manfacturing
process where the metal is heated and
then a force is applied to manipulates the
metals in such a way that the intended
final shape is obtained.
4. SOME MORE DEFINITONS:
• A process in which the work piece is shaped by compressive forces applied
through various dies and tooling.
• Forging is basically manfacturing process involving plastic deformation of
material between two dies to achieve desired configuration.
• Forging is a metal working process in which useful shape is obtained in solid-
state by hammering or pressing metal.
5. DIFFERENT FORGING OPERATIONS
1.UPSETTING :
The thickness of the work reduces and length increases.
2. EDGING :
The ends of the bar are shaped to
requirement using edging dies.
3. FULLERING
The cross sectional area of the work reduces as metal flows outward,
away from center.
4. DRAWING:
The cross sectional area of the work is
reduced with corresponding increase in
length using convex dies.
6. 5. SWAGING:
The cross sectional area of the bar is
reduced using concave dies.
6. PIERCING:
The metal flows around the die
cavity as a moving die pierces the metal.
7. PUNCHING:
It is a cutting operation in which a required hole is produced
using a punching die.
8. BENDING:
The metal is bent around a die/anvil.
7. CLASSIFICATION OF FORGING PROCESSES
• BY EQUIPMENT
1) Forging hammer
2) Press forging
• BY PROCESS
1) Open - die forging
2) Closed - die forging
• BASED ON TEMPERATURE OF
THE WORK PIECE:
1)Hot Forging
2)Cold Forging:
8. • FORGING HAMMER
The upper die and ram are raised by
friction rolls gripping the board.
After releasing the board, the ram falls
under gravity to produce the blow energy.
Forging force = mgh
• PRESS FORGING
Using a hydraulic press or a
mechanical press to forge the metal,
therefore, gives continuous forming
at a slower rate.
W=
𝒎𝒗 𝟐
𝟐
+ ρAH = (mg + ρA)
9. OPEN-DIE FORGING:
Open-die forging is carried
out between flat dies or dies of
very simple shape.
The process is used for mostly
large objects or when the number
of parts produced is small
CLOSED-DIE FORGING (OR IMPRESSION-DIE FORGING):
The workpiece is deformed between two
die halves which carry the impressions
of the desired final shape.
The workpiece is deformed under high
pressure in a closed cavity.
Normally used for smaller components
10. HOT FORGING:
Hot forging is defined as working a metal above its recrystallization
temperature.
Advantages:
• High strain rates and easy flow of metal.
• Recrystallization and recovery are possible
• Forces required are less
Disadvantages:
• Lubrication is difficult at high temperatures
• Oxidation and scaling occur on the work
• Poor surface finish
• Dies must withstand high working temperature
11. 2. COLD FORGING:
Forging is carried out at a temperature below the
recrystallization temperature of the metal.
Advantages:
• Less friction between die surface and work piece
• Lubrication is easy
• No oxidation or scaling on the work
• Good surface finish
Disadvantages:
• Low strain rates, hence less reduction per pass.
• Recrystallization and recovery do not occur.
• Hence, annealing is required for further deformation in subsequent cycles.
• Forces required are high.
12. Tools Needed for Forging:
• Anvils
• Chisels
• Tongs
• Fullers
• Forging Hammer Supplies
Drop hammers
Power hammers:
• Forging Presses
Mechanical forging press
Hydraulic forging press
• Forging Dies
Open die
Closed die
13.
14. ADVANTAGES OF FORGING
• COMPARED WITH: ADVANTAGES OF FORGED BARS AND RINGS
Directional flow that enables the
improvement of impact and mechanical
resistance properties
• Better metallic yield
• Saving in machining hours
• Less quality-related re-work
• Wide range of products and sizes
• Better response to thermal treatment
• Chemical segregations are eliminated
• Facilitates inspection in Non-destructive
Tests
• Minimum porosity in pieces
CASTING
15. • Greater reliability of mechanical
properties by eliminating the welded joint
• Reduction in reprocessing and rejections
• More reliable and better quality pieces
• Easy to inspect
• Easy manufacturing process
Welded products
Effect of forging on microstructure
The formation of a grain structure in forged
parts is elongated in the direction of the deformation.
The metal flow during forging provides
fibrous microstructure (revealed by etching). This structure gives better
mechanical properties in the plane of maximum strain but (perhaps) lower
across the thickness.
The workpiece often undergo
recrystallisation, therefore, provide finer grains compared to the cast dendritic
structure resulting in improved mechanical properties.
17. Disadvantages of Forging
• Some disadvantages of forging are the
high cost and high residual stress produced.
They are often released when they are
machined and cause warping when heavy
cuts are taken.
• Most forging processes are expensive
because of the cost of making dies, so long
production runs are usually necessary to
reduce costs.
18. Forging defects
1. Surface Cracking:
Cause: Excessive working on the surface and too low temperature. High
sulfur in furnace leading to hot shortness
Remedy: To increase the work temperature.
19. 2.Cracking at the flash:
This crack penetrates into the interior
after flash is trimmed off.
Cause: Very thin flash
Remedy:-Increasing flash thickness,
relocating the flash to a less critical
region of the forging, hot trimming
and stress relieving.
3. Cold shut (Fold)
Two surfaces of metal fold against each other without welding completely
Cause: Sharp corner (less fillet), excessive chilling, high friction
Remedy: increase fillet radius on the die
4. Internal cracks
Cause: Secondary tensile stresses developed during forging
Remedy: Proper die design
20. 5.Scale pockets and Under fills:
They are loose scale/ lubricant residue which accumulate in deep recesses of
the die.
Cause: Incomplete descaling of the work
Remedy: Proper decaling of work prior to forging
6.Residual stresses in Forging:
Causes: Inhomogeneous deformation and improper cooling (quenching) of
forging.
Remedy: Slow cooling of the forging in a furnace orunder ash cover over a
period of time.
22. • connecting rods, transmission shafts and gears, differential gears, drive
shafts, clutch hubs and universal joints gears, shafts, levers,spindles to tie-
rod ends, spike harrow teeth and cultivator shafts.
• Corrosion and heat-resistant materials are used for flanges, valve bodies
and stems, tees, elbow reducers, saddles and other fittings.
• Oil field applications include rock cutter bits, drilling hardware, and high-
pressure valves and fittings. suspension clamps, sockets and brackets are
commonly forged for strength, dependability and resistance to corrosion.
• connecting rods, cylinders, discs, elbows, rings, T's, shafts and sleeves.