The French company SAF (Air Liquide Welding group) has presented a plasma-cutting process evolution called DUALGAZ. This new process is designed as an improvement on present methods of cutting stainless steels, especially in the 0.8 mm to 12 mm thicknesses. In contrast to laser cutting, the plasma cutting process can cut stainless steel in greater thicknesses than non-alloy steel at comparable energies (for example, 120 amps will cut through 20 mm of non-alloy steel, but 30 mm of stainless steel). This makes the plasma process very attractive for stainless steels, especially considering that plasma cutting equipment costs only about a third as much as a laser installation. Until today, however, the plasma process was at a disadvantage, especially for stainless steels, due to the inferior quality of the cut surfaces, especially compared to the results obtained by laser cutting. The NERTAJET HP DUALGAZ process developed by Air Liquide combines the characteristics of arc control, as obtainable with NERTAJET HP, with the advantages of special gas mixtures: the introduction of specific constituents into the additive gas mixtures exerts a physical and chemical influence upon the process. Two types of gas combination are possible:
N2/N2+O2, which produces quality cuts of dark coloration and can be used for thicknesses from 0.8 to 2 mm; and N2/N2+O2+CH4, which shows quality cuts of light coloration and produces excellent results up to 12 mm. The nature and proportions of the different gaseous constituents are adapted as a function of the grade and thickness of the stainless steel to be cut, so as to obtain the best possible quality of cut.
