On Thu, 08 Jul 2004 06:03:39 GMT, Seppo Renfors
wrote:

--- snip ----

One
of the reasons for forging is to presever the original grain flow of
the lank and that would be lost if the blank was melted.

My apologies. I should have typed

"One of the reasons for forging is to preserve the original grain
flow of the blank and that would be lost if the blank was melted."

http://www.efunda.com/processes/meta...ng/Forging.cfm explains
it very concisely.


(I have no idea what relevance "long, limp, and straight" (lank) has
to anything here so I'll ignore the term.)

Not true for the particular example given - other similar items are
cast and machined in the traditional manner. Again you only make
totally unsubstantiated assertions and do not speak about the reason
WHY at all! You know, that thing that makes it work and proves your
claims. Haven't you found it on the net yet?

See above

So let is look at this "grain flow" claim:

This is advertising spoof for a Japanese made Golf club:
"Grain Flow Forging exceeds the conventional forging process by
repeating the high pressure compression process to ensure a tight
uniform grain structure through the clubhead. Each head is forged from
one piece ensuring an uninhibited grain flow through the head and
neck."

So there of forging and "grain flow forging" - apparently... but - no
hammering - hydraulically pressed from a single small billet - ie mass
produced by machines where SPEED of production is of prime importance.
Another source says:

"Forging refines the grain structure and improves physical properties
of the metal. With proper design, the grain flow can be oriented in
the direction of principal stresses encountered in actual use. Grain
flow is the direction of the pattern that the crystals take during
plastic deformation."

All fairly straightforward.

So a lot of gobbledegook in reality if compared to your "expert" claim
of "preserves the original grain flow" and "cold". Which is a load of
nonsense for the example I provided - it isn't important. What IS
important is unit speed of production and therefor unit cost of the
production. So slam two dies together and form a crown wheel for a
Mini in a fraction of a second at tremendous pressures like up to
some 50,000 tons and tell me no part of it did melt at any stage! Oh
and you call this "cold forging", when the more correct term is
"Open-die forging" or "Closed-die forging" or even "Two stage
closed-die forging". There is nothing "cold" about it.

Nor is there any melting.

Oh and to finish off with the golf club:

"Ageing the head at elevated temperature optimizes strength and
softness." Oh well...... so much for the "cold"....

700C is elevated but still far below melting.

More than enough of that subject. If you won't learn, then you won't.



Eric Stevens