Re: Forged vs. ?

On Sep 24, 9:35 am, still me <wheeled...@xxxxxxxxx> wrote:
I've seen some quill stems the are marked as "forged". For example, I
have some old SR stems that are forged, others that are not.

What is the difference in the manufacturing process between "forged"
and "whatever"? Is "whatever" usually cast ? I understand steel
forging vs stamping, but what is the difference in process with alloy
parts like stems? Do they repeatedly stamp hot alloy into shape when
forging alloy or is it really just a one step stamping ?

More importantly, what is the general difference in the metal
characteristics when they are done?


How Forgings compare to Castings (quote from http://www.forging.org/facts/faq3.htm
):

Forgings are stronger: Casting cannot obtain the strengthening effects
of hot and cold working. Forging surpasses casting in predictable
strength properties - producing superior strength that is assured,
part to part.

Forging refines defects from cast ingots or continuous cast bar: A
casting has neither grain flow nor directional strength and the
process cannot prevent formation of certain metallurgical defects.
Preworking forge stock produces a grain flow oriented in directions
requiring maximum strength. Dendritic structures, alloy segregation's
and like imperfections are refined in forging.

Forgings are more reliable, less costly: Casting defects occur in a
variety of forms. Because hot working refines grain pattern and
imparts high strength, ductility and resistance properties, forged
products are more reliable. And they are manufactured without the
added costs for tighter process controls and inspection that are
required for casting.

Forgings offer better response to heat treatment: Castings require
close control of melting and cooling processes because alloy
segregation may occur. This results in non-uniform heat treatment
response that can affect straightness of finished parts. Forgings
respond more predictably to heat treatment and offer better
dimensional stability.

Forgings' flexible, cost-effective production adapts to demand: Some
castings, such as special performance castings, require expensive
materials and process controls, and longer lead times. Open-die and
ring rolling are examples of forging processes that adapt to various
production run lengths and enable shortened lead times.

end quote - J.


.

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