High-pressure nitrogen cutting is more frequently being applied to light-gage,
mild-steel applications, particularly with mild steel parts that are to be painted
or plated. The oxide layer produced by conventional oxygen cutting prevents
the paint from properly adhering to the cut surface. Typically, the paint affixes
to the blackened oxide edge which has a tendency to chip and wear off, exposing
bare metal, introducing the possibility of premature part corrosion. This is
a particular concern with internal holes through which bolts or screws are inserted.
Using high-pressure nitrogen in these applications eliminates the oxide layer,
ensuring that the paint or plating attaches to the work piece’s oxide-free
edge.
In addition, using high-pressure nitrogen in mild-steel cutting allows thin-gauge
parts to be processed 15 to 20% faster than conventional oxygen cutting. Because
high-pressure gas does not aid the burning process, the machine and laser can
be pushed to higher cut speeds. With oxygen cutting, a feed-rate threshold is
achieved sooner because of the delay in waiting for the oxygen to take hold
during the burning process.
Currently, nitrogen cutting is limited mainly to lighter gauge mild steel
to 5mm thickness. However, laser OEMs continue to explore the capabilities of
high-pressure nitrogen-assist gas cutting, expanding the scope of cutting possibilities.
