Assist Gas Question.

[smallzer]

Hi Guys,
We're cutting 316 S/S (6mm) @ 2mtr/min using Oxygen assist gas. We've now been told that we can't have any oxidation on the product which means changing gases. Unfortunately Nitrogen will slow us down too much. Does anyone know if an assist gas mixture would help. I.e. could we still cut faster than Nitrogen with say a Nitrogen/Hydrogen mix?

 

[nbucska]

O2 burns the metall as soon it reaches the ignition temp.
so it speeds up the cutting process. If you want to eliminate O2, I think your only choices are to accept lower speed or use a more powerful laser.

<nbucska@pcperipherals.com>

 

[smallzer]

Hi There,

Thanks for the info. We're already using 2.5k/w CO2 slab at full pelt. Guess we'll just have to slow down or remove the oxidation from the product (nightmare!!). Thanks again for your input!

Bryan

 

[Co2Laser]

you could also try using hi-pressure shop air, but it had better be clean and dry! Shop air cut parts can be both welded and painted without secondary operations

 

[smallzer]

Hi There,
Thanks for the reply! I'm afraid we already tried that a few months ago to no avail. The product doesn't go through any welding or painting after the laser process. The product is an expandable completion product for oil wells, basically a huge filter to allow extraction of crude minus all the silt. The backbone of the product is basically sections of pipe with thousands of staggered slots cut into it which allow it to expand. Oxidation is the big problem, removing it from the internal & external pipewalls is no problem, but the slots we cut are 180-200 Microns wide. Removing oxidation from the walls of the kerf is not economically viable. This filter can be downhole for anything up to 20 years and cannot be removed once in place so you can see the problem that oxidation can give us.

Our management want it both ways, they want the fast turnaround that oxygen gives but also want no rusting...hmmm, a tall order!

If you're wondering just what the hell this thing is, visit:

http://www.weatherford.com/weatherford/groups/public/documents/general/wft001703.pdf

Thanks for your input.

Bryan