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Kilnkilnkiln2017

Using Inert Gas (Nitrogen) To Mitigate Oxidation On Stainless Steel

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Good Afternoon,

 

I'm using a Paragon HT22 kiln with the Dwyer gas inlet flow meter.

I'm producing small wire springs (stainless steel) that need to be heat treated in order to secure their final form. In my regular smaller kiln, the oxygen in the atmosphere is reacting with the heated stainless steel and results in pretty intense discoloration (brown/dark purple/etc).

 

Using my new kiln with a tank of Nitrogen gas hooked up, I am able to produce springs that have only a slight blue discoloration. 

This drastic reduction in discoloration/oxidation means that the nitrogen gas is working it's magic, and pushing the vast majority of oxygen out of the kiln, creating an ALMOST perfect inert atmosphere.

 

The question is: IS IT PHYSICALLY POSSIBLE to create a perfectly inert atmosphere in the kiln? Is there something I'm not seeing here? 

 

I'm investigating trying to get a higher flow dwyer meter to allow me to pump nitrogen in at a higher rate, but in my gut, I feel like it's not possible. The removal of this blue oxidation requires a chemical bath, which is certainly within my ability to perform, but I'd really rather not.

 

Does anyone have any experience with these gas injected paragon kilns? Any words of wisdom/tips/tricks?

 

Appreciate the help. 

Kiln on.

 

 

 

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jrgpots    231

You may want to pump in Argon instead of nitrogen. I would suggest making a saggar that has a small inlet for the gas.

 

Jed

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cabako    9

have you checked the purity of your gas?  You could try using lab grade ultra high purity "UHP" nitrogen or argon.  Maybe if the kiln was under vacuum it would be perfectly inert....can you put a kiln that high temp under vacuum?

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have you checked the purity of your gas?  You could try using lab grade ultra high purity "UHP" nitrogen or argon.  Maybe if the kiln was under vacuum it would be perfectly inert....can you put a kiln that high temp under vacuum?

 

Most "nitrogen" that is commonly available is just regular compressed air that it's "purity" is a measure of moisture content, not the amount of nitrogen. That "green" stuff they put in you tires now is exactly that; they just finally figured out a way to charge you $29.99 to put air in your tires; it's still only about 60-70% nitrogen.

 

The problem of putting a kiln under a vacuum lies in the material it's made of and the shape thereof.

 

I've considered flooding with argon before but never had a good enough reason to do so. I'd rather run a bead with my gas that fire a pot.

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