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Old 10-02-2018, 01:14 PM
crystallographic crystallographic is offline
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Originally Posted by David Ward View Post
......
The drops work great for mostly flat or very low crown work, but all I knew was it was CRS. For some parts yet to be formed, quite a bit of dimension will be required, which is the basis of starting this thread.

You mentioned shop annealed metal, what is your process? Heating with a torch and beating has been my way of forming stubborn areas.
Dave

Hi Dave,
Shop annealed or "field annealed" means heat softening with no precise oven controls, so using a torch with some sort of temp. indicator for the hot side, holding the temperature for "soak" and then knowing the cooling rate and how to cool the metal for the quench side.
For annealing mild steel, heating the steel in a darkened room to a very dull red gives the upper limit - a rough 1300F, hold long enough for a thorough soak, and then cover the part with an insulating blanket or wood ash or sawdust ... etc ... and leave it to cool slowly for the quench/cooling side.
A sprinkle of Borax melts at 1365F, so heating from the back will show either color or melted borax, or both.


"Heat and beat" is also known as "hot working" and when working CRS at temps 1300F and above, work hardening is suspended for the duration of the 1300F. Quenching down from that is another matter.

I do not use cold water to quench any of my hot sheet metal work, though others may tout their doing so.

Rapid quenching of hot (1300+F) CRS yields hard metal that is difficult to work, akin to: "take aim at foot and pull trigger."

ASM is my "go-to" for metals info:
https://www.asminternational.org/doc...atTreating.pdf
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"All it takes is a little practical experience to blow the he!! out of a perfectly good theory." --- Lloyd Rosenquist, charter member AWS, 1919.

Last edited by crystallographic; 10-02-2018 at 06:26 PM.
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