440C Heat Treat Foil. Is it a must?

B

buckaroo2219

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Feb 13, 2013
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I recently built a HT oven. I built it so I can move into some other steels besides the 10XX tool steels. Plus it will take alot of the guess work out of heat treating.

I would like to grind some blades from 440c for starters. I will be using the plate quench method when they come out of the oven. My question is is stainless steel heat treat wrap an absolute must? What are the draw backs of not using it. If my thinking is right it would only be more scale build up with out the foil.

Thanks guys. Dave
 
A LOT more. Big difference between a short soak at 1500 and a going to 1500 and holding for 15 then going to something like 1850 for 30 minutes of so. That 1850 soak will be really hard on your steel with oxygen exposure. I haven't tried 440c but, have done a bunch of D2 and some 154. I wouldn't want to try it. Nice thing about air hardening and foil is you can have your blade finished out to say 400 before you HT. Way easier finishing. I made mine so I could flood it with argon, have the argon for my tig and aluminum welding, but have never bothered to try that method.

Try this. Take a piece of your steel and grind it to 220 then HT it and see what happens. I think you will want the foil. I buy mine in 50' rolls to save a few bucks in the long run. Also spend a bit more and get the 309 foil as it takes the heat better.
 
Yes you will want to use HT foil because of scale. It can be done without, but you will be going through more belts. Using foil produces a much more refined result and done right there may only be some discoloring of the metal. I place a small chip of wood into the pouch to absorb oxygen, and if the pouch is made air tight there will be a piece of charcoal from what was the wood chip, and a clean blade with next to no scale.
 
Bufford said:
Yes you will want to use HT foil because of scale. It can be done without, but you will be going through more belts. Using foil produces a much more refined result and done right there may only be some discoloring of the metal. I place a small chip of wood into the pouch to absorb oxygen, and if the pouch is made air tight there will be a piece of charcoal from what was the wood chip, and a clean blade with next to no scale.
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That sounds like a good tip for oxygen absorption, what kind of wood do you use? Or does it really matter?
 
It's another one where if your time is worth anything the foil pays for itself in belts and grind time, so you don't have to leave it rough then do a ton of grinding after HT.
If you're just having fun in your spare time, I envy you! You can certainly get a good usable knife without foil, but it's one of those things that just makes it all mo' betta.
 
I use N690 which is the same as 440c. I estimate that I have made about 1000 knives to date.I simply through a small piece of wood in the furnace and that takes care of the surplus oxygen. I have no problems with scale.
 
cjsdad said:
That sounds like a good tip for oxygen absorption, what kind of wood do you use? Or does it really matter?
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Doesn't matter, just a small chip about the size of a pencil eraser. If the pouch is really airtight you will find that the charcoal is actually still somewhat brown, and your knife will almost have no discoloration at all.
 
Also, (and I'm making an assumption based on the email name and the user name similarities), if you're a supplier trying to push your stock, you need to invest in the appropriate membership.
That, and I'd try to get involved in the community a little bit more, before bringing up 3 year old threads to spam, on a first post no less.
 
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