heat treating 440c with an oxyacet torch

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mike_clark7912

Joined
Jan 7, 2009
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anybody have any tips on the best way to heat treat 440c with a torch i have tried several different methods a few didnt work to well and one worked just good enough the blade is hardend but i think it could be a little bit better
 
im trying to work towards buying and oven but they are so exspensive so for now im just trying to do the best i can and get it as close as possible
 
so what has worked the best for me is i heat the steel till its bright orange and keep it there for about 5 mins feathering it with the torch trying to keep it even then i dip it in warm oil and repeat then i clean it off and put it in the oven at 450 for two hours on a rack with a bent fork to hold it up right and do that twice and so far that way has worked the best
 
so if this is not the best way pleas let me know because i want to do it as right as it can get with a torch till i can afford an oven
 
You'll need to work with a different steel to be able to heat treat with a torch. 440C is a high alloy stainless steel which needs some time at very high temperatures to come anywhere near hardening properly. 1875F for a MINIMUM of 15 minutes, and most people recommend twice that time or more. Holding it at unknown temperatures for short periods of time will not get you there with 440C.

Try your hand with 1084 or some other high carbon tool steel. Stainless is going to have to wait for an oven. I'm all for working with what you have, and I'm not coming down on you at all here. It's just that 440C and other stainless steels, even some high alloy non-stainless steels need time at accurate temps to harden. That's not something that is really possible with a torch.

--nathan
 
thats the problem the closest place it like to me that i can find is like five hours away so i will have to ship them there wait on it to be done then wait on shipping back so when all is said and done they will be tied up for about two weeks because the place only does heat treating on mondays and if i dont time it just right for it to be there the friday before they will sit there for a whole nother weekso i was just trying to save time and shipping cost
 
yeah thats true i just wish there was someone closer that i could just go drop them off in person like in new orleans but i call some places there and they said they have to send there steel to texas so i guess im just gonna have to suck it up and pay the shipping and wait for it thank you
 
O-1 is another tough one. It really benefits from a 10-20 minute soak at around 1475. That being said, it will harden some even with a shorter soak time, but you're loosing a ton of potential in the steel. The hardest thing to do is learn where the proper temp is and then keep it there with a torch without overheating it. Overheating too much will cause grain growth and a weaker, more brittle product. I know of a few people who have claimed good success with a torch and O-1, but I've never done it. I used a forge and had to work hard to keep it at temp for around 5-10 minutes without overheating. I only did a few knive of O-1 this way (for my learning benefit, never to sell) before building a heat treating oven. Also, O-1 is an oil hardening steel, and you can use canola oil heated to 135 in a pinch as a quenchant.

--nathan
 
well how about this cut my loses on the torch and pay someone to do it then so in that case does anyone know anybody that does heat treating within 100 miles of new orleans
 
You may want to look around for local machine shops, 440C should be manageable by any shop with an oven. Other than that, TKS is very affordable if you're mailing them out.
 
I agree with the others that you should send it off to someone to be heat treated properly. But I also have to say that the one 440c blade that I hardened using a torch cuts better than the ones I've done in my oven. Go figure.
 
well the one that came out the best its razor sharp i can sit there and cut through cardboard without any drag and then shave with it afterwards so it holds the edge
 
Vo-Tech schools that have machine tool tech classes
usually have HT ovens. Check with yours, very handy folks to
develop a relationship with
 
Texas Knife Supply does it. A flat rate box full of dozens of knives only costs something like $10 to ship.
Stacy
 
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