foundry castings

[Delwin D Fandrich]

----- Original Message -----
From: "Stephen Birkett" <sbirkett@real.uwaterloo.ca>
To: <pianotech@ptg.org>
Sent: August 26, 2002 9:20 AM
Subject: foundry castings


>
> My understanding is that curing of iron castings is done to allow internal
> stresses from the casting process to stabilize before putting the object
> under external stress, to prevent subsequent warping. I'm not aware of any
> references to strength parameters changing from 'curing' castings.
>
> Stephen


That is my understanding as well--and the benefit even of this is somewhat
questionable. Beyond a certain minimal level of natural stress relaxation,
the foundry people I've talked to about this emphasize that to effectively
stress-relieve a gray-iron casting requires a considerable amount of
heat--800º F is a figure that comes to mind though I could be off by +/-
100º F or so.

Del