SS advice needed...

I'm working on designing a small project, a tamale extruder. The design is mostly tube and sheet, with the need to roll a couple funnel shapes
and TIG weld everything together. I need advice on a SS alloy to use that is relatively easy to cut and machine and to weld, the best filler to use and suggestions on what I need to do for back purging or perhaps making a simple little purge chamber. None of the parts are very big as it's designed to attach to an existing feed auger setup.
Thanks,
    Pete C.
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From "welding engineering" viewpoint 316L TIG's really easily - so long as the weld looks right it is right. Can say that also from experience practicing / playing around. 304L is same for welding(?) - TIG it - looks right is right.
Matching filler. No reason not to TIG 304L with 316 filler.
The "L" is for (very-) low-carbon. These days thermodynamics has revealed a method of blowing down the carbon level in the melt in the steelworks so low there are no metallurgical complications welding stainlesses any more at all at all.
Rich S
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304 is your best option.
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I should have added that you can back-purge with Nitrogen or Argon, but never CO2.
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Ernie Leimkuhler wrote:

I have both available. Since I don't have a dual argon regulator using nitrogen from my LN2 dewar would be convenient.
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What do you actually get if you feed pure 100% nitrogen into a TIG torch? (if it works at all!) what weld do you get with austenitic like 304L? (difficult to confidently guess from science because lots of things would happen - eg. could end up with 100% austenite (no residual ferrite to mop us Phos and Sul) so get solification cracking like 310-series are supposed to be prone to...)
Different thing but...
Ar/2.5%N2 balances the nitrogen level when TIG'ing superduplexes (which have Nitrogen as a necessary alloying element) - neither gain nor loses Nitrogen when TIG'ing superduplex. Meet it on WPS's. Anyone comment about it in practice?
Ar/around 1%N2 recommended for (22%Cr) Duplex - which also "balances" Nitrogen - neither gain nor lose... Also meet on WPS's
There's Ar/5%H2 for austenitic stainless... Anyone comment on that? Tempted to get a bottle delivered to a welder Coding place I go to and have a play with it - see what it really does and get a feel for it...
Rich S
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Richard Smith wrote:

The torch still gets Argon, but since I only have a single Argon regulator, back purging with nitrogen from my Dewar will be convenient, requiring nothing but some hose from the 10 PSI gas outlet.
This is just a tamale extruder, not a space shuttle part so I think I'll be ok :)
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wrote:

I have yet to run into the Argon/Nitrogen mixes, other than reading about them.
The Argon/Hydrogen mixes have been around for a while for welding sanitary and marine stainless with less problems with chromium carbide precipitation.
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Nitrogen is fine cold, but in an arc it becomes an active gas, and has very different properties.
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Ernie Leimkuhler wrote:

So nice and cold from the dewar it should work fine for the back purge.
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"cold" as in not in the arc!!! Nitrogen would become active pulverised by the arc. But as N2 gas, is very inert (?). Up to a few hundred Celsius?
Have I got that right?
Rich S
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