Forging of Metals
Introduction
A metal is shaped by compressive forces Oldest metal working process – 4000BC Can be performed with a hammer and anvil Typical forged products:
Bolts Rivets Connecting rods Gears
Lading-gear components for the C5A and C5B transport aircraft, made by forging. Steps involved in forging a bevel
gear with a shaft.
Outline of Forging and Related Operations
Grain Structure
Parts have good strength High toughness Forgings require additional heat treating
Fig : A part made by three different procedures, showing grain flow (a) casting (b) machining (c) forging
Open-Die Forging
Is the simplest forging process Sizes can very from very small parts to very large parts
Open-Die Forging
Upsetting or flat-die forgingUpsetting or flat-die forging – a solid workpiece is placed between flat dies and is compressed
Barreling caused by frictional forces at the die-workpiece
interfaces Can be minimized if a lubricant is used Thermal effects caused by barreling can be minimized
by using heated dies
Open-Die Forging
Forging force
Impression-Die & Closed-Die Forging
The workpiece acquires the shape of the die cavities while being forged between the two shaped dies
Impression-Die & Closed-Die Forging
The blank to be forged is prepared by: Cutting from a bar stock Preformed blank Casting Preformed blank from prior forging
Impression-Die & Closed-Die Forging
Fullering & edging are used to distribute the material Fullering – material is distributed away from an area Edging – material is gathered into an area
Blocking – rough shaping of the part
Impression dies – give the part its final shape
Precision ForgingPrecision Forging
Used for economic reasons The part formed is close to the final dimensions Less machining is needed Higher capacity equipment is needed Aluminum and Magnesium alloys work well in the process
CoiningCoining Closed-die forging process
Used for minting coins, medallions, & jewelry Lubricants can not be used in coining Can be used to improve surface finish
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