Heat Treating thin Stainless Steel in a propane forge?

D

Danneskjold

Member
Hi again!


I've got a project coming up where I'll be heat treating thin (~1/16") AEBL. But I'll be doing it in a propane forge.

Now, I don't need ultra-hard heat treatment, or cryogenic treatment. In fact, I'll be tempering pretty soft and springy. But heat treating it rather straight is a bit important. I do have anti-scale coating.


What process would you recommend? Thanks!
 
Danneskjold said:
Hi again!


I've got a project coming up where I'll be heat treating thin (~1/16") AEBL. But I'll be doing it in a propane forge.

Now, I don't need ultra-hard heat treatment, or cryogenic treatment. In fact, I'll be tempering pretty soft and springy. But heat treating it rather straight is a bit important. I do have anti-scale coating.


What process would you recommend? Thanks!
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I've never heard of anyone heat treating AEB-L in a forge. It needs to be wrapped in heat treat foil and done in a kiln from my understanding.

That thin of material will suffer from direct heat in a forge. It also needs to be held at a steady temp for a period of time.
 
How are you planning to use the AEB-L? It sounds like you're not looking for a "premium" HT, but a "sorta" HT to have a flexible springy result?

As far as HT'ing in the forge, for sure try to get a foil packet, and for sure use a muffler tube in the forge along with a TC to monitor temp. To be sure it's straight as soon as you pull it from muffler tube clamp between two plates (or sections of angle iron) and cool. Then still clamped between plates/angle iron/flat bar place in oven at around 450°F or so for an hour. If not springy and soft enough place back in forge with temp around 1,000 to 1100°F for a while.

Of course what you're planning to do with the AEB-L can determine how to proceed.
 
This won’t be the answer that you want to hear, but your results will not be what you want to end up with using a forge with AEB-L. It’s that simple. You should consider sending your project out to a pro if you want usable results.

Most anti-scales will break down at around 2000F, AEB-L austenitizes at around 1950 and requires a soak time at consistent temperatures to get carbides into solution. You do not have the required equipment to do what you want, nor do you have the ability to control your forge temperatures to the precision required for AEB-L to be successful. Your temper won’t matter if the HT is inadequate.

I know you are going to do it anyway, but at least now you’ll know the reasons why you’ll be disappointed with the end result. If you send it out for HT you can easily achieve your exact goal.

YMMV, of course. Good luck & let us know how it turns out.
 
Not knowing what the intended use is makes it a little tougher to make recommendations. I have heat treated AEBL in a forge. I did it right as I was starting to get into stainless years ago, and the results were not good. I do have a pyrometer, and could kinda sorta keep the temp consistent. I heated it to 1950 for 15 minutes and plate quenched. It got hard, it would skate a file with ease, but im guessing the retained austenite was very high. I could bend the blade (that was hard enough that a file wouldn’t bite), like it was mild steel. My meter probably reads low, I’m guessing that was probably the reason behind what I believed to be high RA. So, to answer the question, yes you can make AEBL hard using a forge. It’s not something I would ever use on a blade, but if you are just trying to make it “not soft”, it will work. I wrapped mine in foil. Tried the anti scale on a sample piece and it eats pits into the steel like you wouldn’t believe.
 
KenH said:
How are you planning to use the AEB-L? It sounds like you're not looking for a "premium" HT, but a "sorta" HT to have a flexible springy result?

As far as HT'ing in the forge, for sure try to get a foil packet, and for sure use a muffler tube in the forge along with a TC to monitor temp. To be sure it's straight as soon as you pull it from muffler tube clamp between two plates (or sections of angle iron) and cool. Then still clamped between plates/angle iron/flat bar place in oven at around 450°F or so for an hour. If not springy and soft enough place back in forge with temp around 1,000 to 1100°F for a while.

Of course what you're planning to do with the AEB-L can determine how to proceed.
Click to expand...

Cool still in the packet? Cool in oil? With air?


Thanks for the answers, guys. I know I'm being a bit nebulous with what I'm doing and why, but I'm trying something new. Don't know if it'll work, or if I could even sell it for a reasonable price. But if it does work, and people buy it, I want to be the first.
 
Danneskjold said:
Cool still in the packet? Cool in oil? With air?


Thanks for the answers, guys. I know I'm being a bit nebulous with what I'm doing and why, but I'm trying something new. Don't know if it'll work, or if I could even sell it for a reasonable price. But if it does work, and people buy it, I want to be the first.
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Cool it between aluminum plates still in the foil packet...
 
Danneskjold said:
Cool still in the packet? Cool in oil? With air?


Thanks for the answers, guys. I know I'm being a bit nebulous with what I'm doing and why, but I'm trying something new. Don't know if it'll work, or if I could even sell it for a reasonable price. But if it does work, and people buy it, I want to be the first.
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If you try to sell whatever it is, please be sure to disclose your HT procedure so your potential customers know what they are buying.

ETA: one big reason stainless steels require specific times & temps to get the chromium into solution and distributed into the steel’s lattice structure in order to become “stainless”. So hardness isn’t the only thing that is compromised by rough temperature control, but the steel’s capacity for corrosion resistance will also be greatly reduced. Someone purchasing your AEB-L product believing it to be stainless should be made aware of this.
 
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Danneskjold said:
Don't know if it'll work, or if I could even sell it for a reasonable price. But if it does work, and people buy it, I want to be the first.
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Since it's something he wants to sell I'm "assuming" it's not a knife. The OP doesn't seem to be looking for quality HT, but just for something that's "soft and springy" per the first post. Sure will be interesting to find what the mystery object is going to be :)
 
KenH said:
Since it's something he wants to sell I'm "assuming" it's not a knife. The OP doesn't seem to be looking for quality HT, but just for something that's "soft and springy" per the first post. Sure will be interesting to find what the mystery object is going to be :)
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Softer and springier than a knife. But you guessed right. Not a knife.

15N20 is an option for the same project. I've had great success with it in my kitchen knives. But given the price I'd have to charge to make any money on the project, I want to make it as fool proof and easy for the customer as possible.
 
15N20 is an excellent option for forge heat treating. The forgiveness of a simple steel, essentially 1075 (a great spring steel) with a dash of nickel added that gives a bit of resistance to acid staining. Not stainless, but much better than improperly HT'd AEB-L. If you already have success in using it for knives, then your other project will benefit from that experience. Plus, if you are going to sell the item 15N20 will allow you to have a much better chance at consistency in your HT, and you can use published HT curves to have a much better chance of meeting your final tempered characteristics batch to batch. Repeatability helps to ensure quality.
 
I have been trying my best to not respond to this thread but clearly I have failed. However, I am only going to say this; rather than doing an inappropriate heat treat and hope it might possibly work, why don't you pick someone trustworthy who knows steel and tell them what you are doing so they can suggest an appropriate steel and hopefully a forge HT for your project. You can even have the person sign a NDA or something if they will. Clearly you have an idea and are in the R&D phase so seek appropriate help so your idea has the best chance of succeeding. Good luck in any case.
 
Chris Railey said:
I have been trying my best to not respond to this thread but clearly I have failed. However, I am only going to say this; rather than doing an inappropriate heat treat and hope it might possibly work, why don't you pick someone trustworthy who knows steel and tell them what you are doing so they can suggest an appropriate steel and hopefully a forge HT for your project. You can even have the person sign a NDA or something if they will. Clearly you have an idea and are in the R&D phase so seek appropriate help so your idea has the best chance of succeeding. Good luck in any case.
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I'm definitely going to experiment, and not do everything in one go. If my crude heat treating isn't working, I can always switch over to 15N20 and have someone do the AEBL proper.
 
I am a strong defender of people doing things their own way and not being ridiculed for experimenting outside of accepted norms. That being said, to a knifemaker who uses stainless steel, HT-ing in a forge is so far off of the reservation (so to speak) you are not likely to get many responses which will help. I have no idea what kind of internal problems you may be imparting to that steel and what problems they may cause later. Couple that with the fact that you give no information on what the part will be used for and what stresses it will receive in use and there is not enough info here for anyone to help you in any meaningful way. That is why I suggested getting an expert and a NDA. I hope whatever you are up to works out well for you.
 
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Chris Railey said:
I am a strong defender of people doing things their own way and not being ridiculed for experimenting outside of accepted norms. That being said, to a knifemaker who uses stainless steel, HT-ing in a forge is so far off of the reservation (so to speak) you are not likely to get many responses which will help. I have no idea what kind of internal problems you may be imparting to that steel and what problems they may cause later. Couple that with the fact that you give no information on what the part will be used for and what stresses it will receive in use and there is not enough info here for anyone to help you in any meaningful way. That is why I suggested getting an expert and a NDA. I hope whatever you are up to works out well for you.
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Remember Chris, the OP did say "Softer and springier than a knife. But you guessed right. Not a knife." so there's no telling what he's got in mind. Seems like he might be tending toward 15N20 also which would be a wise move regardless of use he's got in mind.
 
You know, I was thinking….if it doesn’t need to be hard, like knife hard, and springy/tough is kinda what you are going for, would a different metal entirely serve your purpose? Titanium might work fairly well, it’s pretty springy. No heat treat needed, it’s got corrosion resistance too. Just spitballing.
 
I actually did think of something which may help. If you need spring-like qualities AND corrosion resistance that can be HT'd in a forge, then go with a spring steel which can be HT'd well in a forge then use an industrial coating such as KG Gun Kote for the corrosion resistance. May solve both your problems. Gun Kote is fairly straight forward to apply and cure. No special equipment needed.
 
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