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O1 questions


David Pessall
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After quenching O1 tool steel can you let it cool to room temperature before tempering? Using a brick forge and I can only get 2 blades in at a time.  I'd like to get 5 done and temper at same time. Would this be a problem?

Thanks again 

 

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In that case, I'd just do 'em two at a time and straight into the oven with the others. As long as the last one gets its full hour of tempering, the extra time won't hurt the first one a bit.  Then you can do them all in one go for the second tempering cycle.

If you let the first ones sit on a warm brick or a pile of kaowool while you harden the others, it possible the first ones might spontaneously crack.  Depends on the geometry and how much stress there is in the blade.  It's a gamble, in other words.  Probably not that big a gamble, but a gamble nonetheless.

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29 minutes ago, Alan Longmire said:

... it possible the first ones might spontaneously crack.  

It is amazing to me how often this hobby/craft makes me feel like the coyote does after he realized he ran off the end of the cliff 100 yards ago... 

 

  • Haha 1

-Brian

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Another option is to keep some very hot oil, or possibly boiling water handy.  Go straight from the quench to that.  Either it will keep the blade from fully finishing the transformation (if you put it in after Ms but before Mf) or it will do a fairly light temper and reduce the harshest stresses.  Then just let the blades get to room temp between the hot liquid and the temper and you're good to go.  

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The funny thing is, I used O1 for years and never knew about this. I'd quench, set aside, and get around to tempering whenever it was handy. I can't remember any of them ever cracking post quench. (Not suggesting this isn't good advice. Jerrod and Alan know their stuff. Just sharing an "ignorance is bliss" story).

 

I also did pattern weld in a farrier's forge that had no airflow choke to produce a reducing atmosphere. No one told me you couldn't weld w/ a farrier's forge, so I did it anyway. 

 

 

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"It is not the critic who counts; not the man who points out how the strong man stumbles, or where the doer of deeds could have done them better. The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood, who strives valiantly; who errs and comes short again and again; because there is not effort without error and shortcomings; but who does actually strive to do the deed; who knows the great enthusiasm, the great devotion, who spends himself in a worthy cause, who at the best knows in the end the triumph of high achievement and who at the worst, if he fails, at least he fails while daring greatly." -- Theodore Roosevelt

http://stephensforge.com

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I've had steel sitting in a vice for a couple days crack on me out of nowhere.  I was sitting a few feet away when it cracked and it scared the crap out of me (luckily just figuratively).  I was in the process of doing a 3 point bend to straighten out a bend, got interrupted and I guess I didn't back off the vice as much as I thought I did.  There is always a chance of stresses being too much.  We can just do our best to minimize the chances, or at the very least understand the risks.  It drives me nuts at the foundry that there is a lot of air hardening stuff we do that can go a day or more between fan quench and the temper cycle.  Haven't had anything crack yet (apparently).  

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I did as suggested. Did a couple at a time in furnace, quenched, put in oven. Added a couple minutes in oven for opening door for each set. Second time in oven all at once. Turned out fine.

 

 Thanks again for the help!

 

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