[TheForge] shield gas and plasma cutting

[terry l. ridder]

hello;

the reason nitrogen is/was used as the shield gas in plasma cutting is
actually pretty basic. when oxygen was used as the shield gas the life
of the electrodes and the torch were short due to the reaction of plasma
created from oxygen and the material used for the electrode.

using nitrogen as the shield gas in plasma cutting does create a
nitrogen zone in the cut which needs to be taken into account if welding
the cut edge.

on of the better urls detailing the history of plasma cutting is:

plasma cutting history
http://www.hypertherm.com/technology/plasma_history.htm

-- 
terry l. ridder ><>