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winegar
05-13-2011, 06:13 PM
Hey guys been trying to cut stainless and it looks really jagged and not clean lines at all!... I have tried many cut heights and speeds and power... but still the same.... someone i know mentioned that i might need to use gas of some type to cut it instead of air?.. Thanks guys!

jimcolt
05-14-2011, 09:10 AM
While stainless cutting is different than caron steel cutting....if you have the right plasma system stainless can be cut very well. If you are talking about an air plasma system....air has a 20% content of oxygen, which gives an exothermic boost to carbon steel cutting. Since stainless does not oxidize easily...the cutting process is simply thermal (melting) so you typically get a bit more bevel, and a blackened (discolored) edge.

Most air plasma systems can use either air or nitrogen as the plasma gas.....I do not recomend that you use gases that the systems are not designed for....damage to the torch and gas distribution system can occur....or a fire can occur.

You can improve edge metalurgy (cleaner, weldable edge) if you use nitrogen, and submerge the stainless steel underwater....this keeps oxygen (in the surrounding air) away from the cut edge. Industrial, high definition plasma cutting systems use a variety of gas combinations in their dual flow, liquid cooled torch designs to cut stainless with excellent results. Mixtures of Nitrogen and Hydrogen or Argon and Hydrogen are often used for the plasma gas, with a nitrogen shield gas on these systems.....gas mixing and flow systems must be highly accurate and are microprocessor controlled in order to make these processes work.

I have great luck cutting stainless with my Hypertherm Powermax85 air plasma....here are a couple of pics of 1/4" and 3/16" parts I have cut. I actually made the large stainless steel signs that are in front of 5 of Hypertherm's facilities...as seen in the pics. I follow the specifications for speed, cut height, amperage, pierce height exactly as listed in the Hypertherm manual.....with great results.

Jim




Hey guys been trying to cut stainless and it looks really jagged and not clean lines at all!... I have tried many cut heights and speeds and power... but still the same.... someone i know mentioned that i might need to use gas of some type to cut it instead of air?.. Thanks guys!

winegar
05-14-2011, 12:58 PM
Wow... that is 1000% better than mine!... I will have to check out my plasma cutter and see what gas it can be used with!... Thanks for the reply!

jimcolt
05-14-2011, 07:46 PM
The cuts in my pictures did not use any fancy gas......compressed air as the Hypertherm Powermax units are designed to use, at 45 amps. These cuts wer done on a downdraft table at book specs.

Jim Colt

lockyg
03-15-2013, 06:15 AM
Hi Jim,

What grade of stainless did you use, and what finishing was required after the cutting - I have been asked to produce some letters for use on the outside of a building.

Thanks

Geoff

jimcolt
03-15-2013, 06:45 AM
The large sign in the pictures I posted was 1/4" 304 stainless, the small part was 3/16" 304 stainless. Neither had any cleanup after cutting. Expect the edges to be oxidized (from the oxygen content in air) and brownish. If you need to clean up the cut edges you would need to do some wire brushing or polishing of some sort. I have done some lettering out of the same material and used a die grinder to clean up the edges.
Jim Colt


Hi Jim,

What grade of stainless did you use, and what finishing was required after the cutting - I have been asked to produce some letters for use on the outside of a building.

Thanks

Geoff