----- 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
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