Plasma Cutting Stainless SteelStainless steels frequently need to be cut to size or shape and plasma cutting is the most frequently used method for thermal cutting. The process may be operated with a single cutting torch or with multiple torches and may be linked in with numerical control equipment. Plasma cutting is a very efficient way of cutting and produces good, clean cuts with little disturbance to the chemistry of the stainless steel and so does not adversely affect its corrosion properties. The plasma gas may be pure argon or nitrogen, but may also be hydrogen-nitrogen or argon-hydrogen mixtures. While argon gives the hottest plasma it is expensive and cheaper nitrogen or nitrogen-hydrogen mixtures are perfectly satisfactory up to 38mm thick. With nitrogen as the plasma gas, 10mm plate may be cut at 5m/min and 25mm plate at up to 1.9m/min. With argon-35%hydrogen, 50mm plate may be cut at 0.5m/min and 100mm plate at 0.25m/min. The main safety issues are electrical, radiation, fume, noise, and inert compressed gases. Cutting may be carried out with under-table fume extraction or in a water bath. The latter has the advantage of reducing noise and radiation as well as fume.
|
