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March Madness Meme [Mar. 7th, 2006|05:24 pm]
Doug Ayen
So. Have you ever wanted to ask me a question? Blacksmithing related, knifemaking related, personal, or anything else? Please allow me to prove my "Male Answer Syndrome" affliction!


[User Picture]From: perspicuity
2006-03-08 05:23 am (UTC)
please compare/contrast the differences/qualities of anneal, vs, harden, vs temper ; and why it's important to anneal a 51200 ball bearing or other suspect material before welding or heating to absurd ranges - in particular rare earth magnets. :)

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[User Picture]From: blackanvil
2006-03-08 03:13 pm (UTC)
Joe, I'm pretty sure you know the answers to those already, but . . .

annnealing is softening and removing the stresses from forging operations, hardening is making the blade harder (and more brittle), and tempering is relieving the stresses from the hardening and softening the blade to increase toughness.

I've heard, but never personally seen or know anyone who'll say it happened to them, that the larger ball bearings, 51200 or otherwise, need to be annealed or they'll explode. The process of heating to welding temperatures should make the steel plastic enough that any stresses should be relieved in the process -- assuming you're doing it right. You never want to "shock" tool steel from a cold state to uber-hot, that would be just asking for micro-fractures and other problems. Leaving the steel in a hot but shut off forge for a minute should do the job; or heating in a cold forge. But an "explosion" seems unlikely unless you're really doing something stupid (like taking a 3" ball bearing from a liquid nitrogen dip to a fully-hot ready-to-forge-weld forge.)

You should never put a rare-earth magnet in a forge. not only are they toxic, not only can they explode, but they can contaminate your forge with exotic chemicals that will make welding a bitch, if not impossible. Oh, and if you're talking about the United Nuclear uber-magnets, I'd not want to take one of those into the workshop -- there's a lot of loose iron around, some of it quite sharp.

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