Great answer Bryant. I would add that cold forging is superior because it eliminates voids and provides better grain structure. High quality aircraft castings are typically rated 1/3 lower in strength than comparable forgings for structural analysis.
Joe B-Z
GNNJ
> Donald Gillies wrote:
>
> What is melt-forging and is it still used?
>
>
> Don,
>
> The "Mighty" series of cranks were cold forged. "Melt Forging" is actually
a
> marketing name for high pressure casting. The alloy is forced into the
mold
> under high pressure (over 10,000 psi) and then cooled quickly with a water
> jacket around the mold. The Hierarchy for crank manufacturing is: Cold
> Forged, Hot Forged, Gravity Cast, Melt Forged.
>
> What separates all these process is the amount of money needed for tooling
&
> the time needed to complete a part. Cold forging requires the highest
number
> of dies, Hot forging uses fewer and Gravity casting & melt forging only
one
> mold but melt forging is quicker.
>
> Hope that helps.
>
> Bryant Bainbridge
> Portland Oregon