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Thread: O1 heat treatment
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06-02-2007, 12:02 PM #1
O1 heat treatment
Last week I got this heat treatment explanation from Wayne D.
It is for O1 (or in belgium / germany: 1.2510) steel. I am posting it here because it might help others as well, and this way I know where I can find it when I need it.
O1 is an oil hardening steel, so wants quenching in oil. If you do it in ice water you run the risk of cracking the steel.
From Wayne:
I use motor oil in a large turkey roasting tray
it's simple to heat treat O1,
you need a pan of motor oil a magnet aluminium kitchen foil (bacofoil) and a kitchen cooker preheated to 250 oC or gas mark 8
heat the steel in the fire until it goes a cherry red colour then touch it against the magnet if it's attracted it's not hot enough yet,
keep heating until the steel is not attracted (antimagnetic) then quench in the oil keeping all of the O1 under the surface move it around a little to stop the oil getting too hot.
take out of oil, clean with a cloth and repeat this heating 2 more times.
* at this point the O1 is very brittle so don't drop it *
when you've done this wrap the O1 in the aluminium foil - it stops your kitchen smelling of burned motor oil and helps even out the heating process
then put it in your preheated oven for 1 hour.
take it out of the oven and allow it to sit on the worksurface until it's cool enough to pick up with your hands comfortably - but not cold
then place back in the oven for 1 hour, remove allow to cool down to hand temperature,
place back in oven for 1 hour and then when you take it out allow to cool totaly.
when you remove the foil the metal should be in the range of light brown/ straw / golden/ yellow colour
this means you have heat treated it to between Rockwell 60 and 62.Til shade is gone, til water is gone, Into the shadow with teeth bared, screaming defiance with the last breath.
To spit in Sightblinder’s eye on the Last Day
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06-02-2007, 01:23 PM #2
Would just turning off the oven and letting it cool even more gradually improve the treating process?
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06-02-2007, 04:39 PM #3
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06-03-2007, 02:46 PM #4
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Thanked: 2Hi Gents,
I have actualy tried this and what I found was that the steel didn't heat treat properly and came out too soft. then when I needed to place the steel back in the oven, the oven itself was too cool, and then took time to heated back up to the temperature I needed.
remember the Oven needs to be pre-heated to the temperature before the steel
goes in.
This is my way of doing it from experience and training with other Smiths I know - BUT, I have no doubt others may have different ways of doing a Heat treat for O!
hope this helps
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06-04-2007, 04:09 AM #5
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Thanked: 2204Thats the sequence that I learned also but applied to W1-W2(old files) and 1095 steel. The tempering in the oven is done at 200 C or 400 F. What I was taught was that you have 1 second to get the steel from the forge and into the quench oil.
Randolph Tuttle, a SRP Mentor for residents of Minnesota & western Wisconsin
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05-12-2008, 04:34 AM #6
Oh, goodie, now I get to pass on all the knowledge that Mike Blue, Tim Zowada and Kevin Cashen have drummed into my head...
O1 is a very good steel, but it's not the best steel for beginners. On the plus side, it's less likely to crack than some other steels. But it needs to be treated properly if you're going to get full hardness out of it.
O1 is an alloy with a lot of chromium in it. The chromium has the effect of pulling carbon out of the steel and holding onto it. This causes the steel to be softer unless you do something about it.
To get maximum hardness out of O1, you need to heat it above the temperature where the carbon starts to dissolve back into the steel--somewhere around 1450 degrees F. Then you have to hold it there for a while without overheating it. That's the tricky part. Unless you're using a decent forge and a thermometer, or an electric heat-treating oven with digital controls, you'll probably overheat the steel pretty quickly. That will result in softer, weaker steel.
I've worked out a pretty good process for O1, but better equipment would make it more precise. Here's what I do:
Heat the steel to 1450 F, hold it for two or three minutes, then allow it to air cool. This relieves forging and grinding stresses; it's called normalizing. I normalize three times.
Heat to 1450 F and hold for 15 minutes. This is called soaking, and it allows the carbon to dissolve back into the iron.
Quench in Parks AAA quench oil, preheated to 130 F. This is a slow cooling oil. You could also use vegitable oil or any number of other oils, but this stuff was designed specifically for heat treatment. For about $10 a gallon, I'd rather just use the best.
After a minute, take the steel out and allow it to air cool. When it's cool enough to touch, put it in the oven to temper it. I temper at 425 F for two hours. Allowing the steel to cool down in one hour cycles isn't necessary.
If you do everything right, the blade should be harder than any vintage razor you've ever tried to hone. If I only temper at 400 F I can't even get the thing honed, it's so hard.
That's just how I do it.
Josh