Re: Interaction between iron and copper at 770 C
From: Uncle Al (UncleAl0_at_hate.spam.net)
Date: 03/06/05
- Next message: jtnospam_at_yahoo.com: "Re: Commercial product for pourable foam molded parts?"
- Previous message: Mark Thorson: "Interaction between iron and copper at 770 C"
- In reply to: Mark Thorson: "Interaction between iron and copper at 770 C"
- Messages sorted by: [ date ] [ thread ]
Date: Sun, 06 Mar 2005 14:52:35 -0800
Mark Thorson wrote:
>
> I'm planning to anneal a structure containing mild steel and iron
> above the Curie point of iron (769 C). This is for the pole
> structure of an experimental electric motor. I need to hold
> some iron wires in the end of a mild steel slotted shaft.
> I looked at using clips or retaining rings of various sorts,
> but the clearances are pretty tight. Then I got the idea of
> cutting sections of copper tubing, and pushing them over
> the end of the shaft like a collar. This would require minimal
> clearance to adjacent structures, but I am concerned that
> the copper might interact with the iron or steel during the
> annealing. The forces pushing the wire out of the slot would
> be minimal, but I'm concerned that the copper might try
> to alloy with the iron, perhaps breaking the wires. Or, it
> might try to alloy with the steel, breaking the copper collar.
>
> Does either of these scenarios seem likely, or even plausible?
>
> I haven't worked out the exact temperature profile, but
> just guessing I would say ramp up from 25 C to 770 C
> over an hour, dwell at 770 C for 15 minutes to 1 hour,
> then ramp down as slow as possible, perhaps 24 to 72
> hours. If possible, it'll be in a reducing atmosphere.
> (I haven't checked with the pottery kiln people to see
> if they offer that service, but I believe some glazes require
> a reducing atmosphere, so I would think it is offered.)
>
> If the copper collars weld themselves to the steel shafts,
> that would not be a problem as long as they don't break.
> I don't intend to take apart the assembly.
Do a test case and find out. Copper has problems with air oxidation
to the red then black oxide with swelling. Do it in an inert or mildy
reducing atmosphere.
Is the copper tubing thermally annealed? Will relaxing residual
stresses couse it to shrink and seize or expand and fall off?
-- Uncle Al http://www.mazepath.com/uncleal/ (Toxic URL! Unsafe for children and most mammals) http://www.mazepath.com/uncleal/qz.pdf
- Next message: jtnospam_at_yahoo.com: "Re: Commercial product for pourable foam molded parts?"
- Previous message: Mark Thorson: "Interaction between iron and copper at 770 C"
- In reply to: Mark Thorson: "Interaction between iron and copper at 770 C"
- Messages sorted by: [ date ] [ thread ]
Relevant Pages
|
