When metal is hot, it is in a soft and pliable condition
allowing it to be easily formed under
pressure without breaking. This process is called
Metal is strongest
in the direction of its grain flow. Machining cuts
through the grain, thereby weakening the metal. Forging
causes the grain to flow in the shape of the part.
Drop forging is a mass
production technique which hammers the metal between two
dies. Half of the die is attached to the hammer (upper
section) and half to the anvil (lower section). The hot
metal is placed in the lower half of the die and struck
one on more times with the upper die. This forces the
metal to flow in all directions, filling the die cavity.
Excess metal squeezed out between the die faces is
called flash or flashing. After the
forging is completed the flash is cut off in another
press with a trimming die.
Drop forging is suitable
for producing small and medium size objects, such as
wrenches, gear blanks, machine parts, fasteners, engine