Using Nitrogen in a kiln

[Willie71]

I am considering using nitrogen in my kiln as an inert gas. (I know it’s not really inert, but for this use it should work.) Has anyone used inert gasses in their kiln? I got advice from Larrin, and he informed me that 150-200 millibars is recommended for nitrogen steels in a vacuum furnace.

Does anyone have any experience with flow rates to make this work?

 

[kuraki]

JT was doing it but decided that even with the time spent wrapping, wrap was more economical for him.

I have a tube for my kiln plumbed for gas but have never gotten around to installing it.

 

[Mike Read]

When I first started making I had some HT done by a knifemaker who was using Nitrogen in his kiln. He did not use it for long saying that it was too much hassle and not cost effective.

Also I can say for sure that I get much cleaner results in my kiln using foil than he did in his using Nitrogen.

 

[Willie71]

Thank you for the replies. Part of my thinking was to use it with the nitrogen steels to prevent loss of nitrogen at the surface. If that would work, I was also thinking of using it with steels like V4e, z-wear, M4 and getting the knifes to near final dimensions and quenching into a salt bath at 900f. I can’t figure out a way to do that with foil using a traditional kiln.

I have a friend who works at Praxair, who could set me up pretty economically, but it looks like this might be more hassle than it’s worth. I might get a bottle anyway, as I could use it to charge motorcycle shocks when rebuilding them, rather than making a trip into town for a local shop to do it. If I do try, I’ll report results back here.

 

[elementfe]

I am considering using nitrogen in my kiln as an inert gas. (I know it’s not really inert, but for this use it should work.) Has anyone used inert gasses in their kiln? I got advice from Larrin, and he informed me that 150-200 millibars is recommended for nitrogen steels in a vacuum furnace.

Does anyone have any experience with flow rates to make this work?

My Paragon has a caution against using inert gases, something about how they affect the protective oxide layer on the element. Might be worth checking with the manufacturer, might not be an issue with yours.

 

[Willie71]

My Paragon has a caution against using inert gases, something about how they affect the protective oxide layer on the element. Might be worth checking with the manufacturer, might not be an issue with yours.

Thank you for that. This looks like a no go.

 

[hugofeynman]

Thank you for the replies. Part of my thinking was to use it with the nitrogen steels to prevent loss of nitrogen at the surface. If that would work, I was also thinking of using it with steels like V4e, z-wear, M4 and getting the knifes to near final dimensions and quenching into a salt bath at 900f. I can’t figure out a way to do that with foil using a traditional kiln.

I have a friend who works at Praxair, who could set me up pretty economically, but it looks like this might be more hassle than it’s worth. I might get a bottle anyway, as I could use it to charge motorcycle shocks when rebuilding them, rather than making a trip into town for a local shop to do it. If I do try, I’ll report results back here.

Hey, Warren! Great decision quenching in molten salt bath! Exactly as Fredrik Haakonsen does! He also quenches his V4e knives in 500C molten salt pot. But he uses (or used) an “usual” furnace (not vacuum) with knife blanks wrapped in stainless foil.

If you can go the extra mile and set up a full molten salt bath heat treatment equipment, with high temperature salts to harden, that would be superb!