can stainless be HT'ed in a propane forge

Bailey Knives

Bailey Knives

Knifemaker / Craftsman / Service Provider
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Oct 18, 2004
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Is there any way to heattreat stainless in a propane forge. I dont know what the exact temps are and I know that you need to soak stainless for certain amounts of time. Someone told me that 440c was able to be done in a propane forge, and I was just trying to get the process down.

My forge is a homemade deal with a venturi burner.
 
I'd think if you got a good pyrometer and sat there carefully watching the temp and constantly adjusting the gas as needed, it'd be doable... but a pretty big pain in the rear.
 
Yes...with practice you can heat treat 440C in a propane forge. Someone will chime in right behind me and say that I'm wrong, but that doesn't change the fact that I do it and so do several other people.
I'd recommend that you become well versed with heat treating carbon steel in your forge before you try stainless, and 440C is the only stainless that I know of that you can do this with.
The process is very close to heat treating carbon steel, you just hold the peice at temperature for a longer period of time. I can't give too many specific details, because what works in my forge, may not work in yours. You have to do a fair amount of experimenting with it to get the results you want.
The best thing to do is search for "triple quenching 440C" in this forum(might be in the archives too) and read about it. Ed fowler got us started on the idea awhile back, and some other folks got involved and did some experimenting. Your best off to start out with the methods listed there and fine tune them to your equipment.
I would never suggest that this method is superior to a digitally controlled oven or anything like that, but if you put the time in you can get good results.
 
Matt is correct.If you invest a bunch of blades (10-15 maybe) and a lot of time and propane,you MIGHT be able to learn to do a so-so HT job on 440,or maybe not (most of those blades will be forge fodder).If you invest $10 you can get the blade professionally treated with Cryo.I'm not saying that it can't be done ,I'm just saying it isn't cost effective or quality effective.
Stacy
 
Answers when I ask the ?????
Hello George: I forged my 440 blades down from two-inch ball bearings. I ground them clean, then heated to non magnetic and quenched in 135 degree pre heated Texaco type A quenching fluid, letting them cool down in the oil to room temp. I tested blades from one quench to 7 as I remember. Three quenches seemed to be the best bang for the buck. I tempered at 350 degrees they passed the edge flex test, two passes on the steel right and left. They did not cut as good as 5160 forged blades at that time. I did not try all the experiments possible or seek any laboratory assistance. It was fun at the time, and probably they could be taken further. I did not try any rust experiments so do not know if the 'stainless quality' was present.

Hi George,
We were at the annual Flint River Knife Club's annual picnic yesterday in Georgia and I was taking to some of the knife makers there about oil quenching 440C. I told them how I did it and it only checked 50 on the Rockwell C scale. The general consciences were not to normalize and only quench once. They seem to think it needed to get to 2000 degrees at quench and the oil needed to be around 170 degrees. Temper twice at 350 degrees then thrown in the freezer overnight. I'm going to try that tomorrow and see what happens. Have you tried it yet? Let me know how it comes out.
 
Thanks guys. I guess It would be worth my time and money to just send it out for HT and if that is the case, I would look into different stainless. When you send out for HT how near finished are the blades, same as for carbon steel? (80-120 grit finish and 1/16+- edge is what I normally do)
 
I do mine in a stainless heavy walled pipe with a thermocouple coming through a cap on one end of the pipe.My forge uses two burners and is 18" long.I can keep the temperature within ten degrees.I do wish i had a kiln though.
 
derkins said:
and if that is the case, I would look into different stainless
Click to expand...

Honestly, all stainless steels (that I know of) will give you the same problems, they all specify a tricky HT. The carbon steels should be home HTable though, if you prefer not sending blades out for HT then that'd be the way to go unless you want to buy a HT oven.
 
Take stainless steels to a finer finish before HT.I go to 400.The edge can be finer,too.1/16 to 1/32.It usually comes back looking slightly grayer,but otherwise identical to the way it looked before HT.
 
thanks, I have done plenty of carbon steels myself, I was just considering an attempt into stainless.
 
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