Nitrogen Stainless Cutting Gas Usage? Powermax 45

[Capstone]

I would think most of us use straight compressor air, so aside from dryness and pressure, most plasma table users aren't thinking about the actual amount of air used.

But, I need to cut some 3/8in Stainless and buy the Nitrogen.

Where can I find a chart for the amount of gas used per inch based on thickness and the size of the plasma cutter?

I have a Hypertherm PM45

Thanks in advance for the help.

[motoguy]

Just a WAG here. I don't have 3/8 stainless in the chart for 45A. It's in the chart for 65A, though. For 65A 3/8" stainless, cut speed is 40 IPM. My Powermax 85 manual states 6.7scfm @ 85psi. So, 40 inches in a minute of cutting, and 6.7 SCF in that same minute. This would indicate that each inch of cut will use approx .1675 SCF of gas (at full cut speed. Corners, curves, or other slower IPM areas will us more gas per inch). Of course, you have the post-flow which will add to that, as well as the pierce time, etc.

It would seem that .1675 SCF x number of inches in your file would give you a "good starting point, but not enough due to IPM slow down areas and the post flow/pierce" amount of gas needed (for the 65A process. The 45A process would be cutting slower, therefor needing more gas.).

[jimcolt]

Try cutting your stainless with air. You will get a bit more edge oxidation, but generally less dross. The best cut on stainless thicker than 3/16" is using Hypertherm's F5 cutting process (95% Nitrogen, 5% Hydrogen premix gas). The Hydrogen content acts as a reducing gas that strips away the ambient air from the cut edge...leaving a shiny, non-oxidized edge, better than with straight nitrogen or air. Jim Colt Hypertherm

[rbmgf7]

I've cut 3/16" 304 with straight air using steel speeds. The edges weren't that bad. I chased the edges with an abrasive wheel and the edges look great. Make sure you have adequate ventilation and wear a mask!

[hsolve]

You will also find that the top edge will round slightly and the edge finish will be 'blueish'. I did some 10mm quite some time ago as a test, worked OK, but did consume the Nitrogen quite quickly. Also I ended up using a high flow high pressure regulator. The standard welding regulator would not cut it.
As mentioned above I did it on 65amps and tips.