Adding Argon to AEB-L HT Pouch

MTBob

MTBob

Well-Known Member
Using inert gas (Argon mostly) is a common feature with many HT ovens. The benefit is a reduction or elimination of surface scaling. I opted to not add that feature when I got a Paragon oven because filling the entire chamber with gas is costly and, in my opinion, doesn't make sense for my low volume hobby level knife making.
So, I decided to try what may be perhaps the next best thing - adding gas to the stainless steel pouch just before sealing the end. I disconnected the Argon hose from my TIG welder, set the flow to about 30 CFH, and ran gas in the open end for about 20 seconds.
I rarely grind the bevel pre-HT, but I wanted to see what distortion I might get on the edge. It has a rough unfinished hollow grind and plunge cut. I was expecting to see some distortion on the ground edge. After Cryo (with a clamp) and then tempering (with a clamp) the knife has remained straight and flat - no distortion.
Here's the result after quenching. There is virtually no scale, only color variation.
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I ran a nitrogen purge in my Paragon for a while. It’s nice on carbon blades because it leaves them clean. I don’t anymore, in the end it was kinda more hassle than it was worth.
 
Did this result come out better than just using the stainless foil pouch alone? Were you getting much scale or decarb on your AEB-L without the Argon?
 
Owl said:
Did this result come out better than just using the stainless foil pouch alone? Were you getting much scale or decarb on your AEB-L without the Argon?
Click to expand...
Good questions. I've never had much decarb on AEB-L. But, depending on whether I used a paper insert (or how much paper), I would get varying degrees of black surface coating. That discoloration would grind off. The Argon gas seems to have eliminated the dark discoloration and added a curious set of random colors. I should have done a three set test: with Argon in one, paper in one, and nothing in the third packet.
After looking at the coloration of the steel after HT, it appears to me to make an interesting design on the blade. If I can hold my grind edge tight while finishing the hollow grind, I may try to polish the blade in it's current state in an attempt to retain the coloration. We'll see how that turns out, stay tuned...
 
I bought some stainless flatware that had stickers on them that were impossible to remove, I tossed them in the HT oven at 900 to take the stickers off. Colored them purpleish. There’s still traces of purple on the forks, that have been used and ran through the dishwasher for about 10 years, so the color is pretty durable. Would be pretty cool if you can get it to work on a blade
 
I squinted a little WD40 in my SS pouch and the knife came out beautifully colored. The pouch did swell up a bit.
 
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