Why use Nitrogen for laser cutting?
The use of Nitrogen in laser cutting produces a clean edge during the laser cutting process, an assist gas needs to be used to blow away the molten material (KERF) caused by the laser. Traditionally Oxygen would be the gas used but Nitrogen offers up more benefits when cutting steel.
Nitrogen Cutting v Oxygen Cutting
As an inert Gas, Nitrogen has no reaction to the molten metal ( KERF) during the cutting process. By using Nitrogen, this removes Oxygen from the cutting Zone, and prevents the material from Oxidising or discolouring.
The benefit of this is a clean edge that does not require any additional process for cleaning the material cut edge.
Oxygen on the other hand reacts with the metal in an exothermic reaction. That means more heat is produced around the cutting site, speeding up the cutting process.
The downside is that oxidation causes damage to the cut edge, which means a further clean-up process is required. You can use manual grinding, chemical removal, or other methods to finish the edge. In contrast, nitrogen cutting produces a clean edge.
Plasma Cutting Stainless Steel with Nitrogen
Most manufacturers prefer to use Nitrogen for the plasma cutting process due to the clean edge finish Nitrogen provides. There is no additional process required and as such offers a quicker more cost effective option.
Laser Cutting Mild Steel with Nitrogen
Using Nitrogen for laser cutting mild steel is suitable for shaping, although recommended for thin material only. If the material is thicker than 1/8″ in ( 3 to 4mm) the cutting speed is much the same as that for Oxygen cutting.
The decision to use Nitrogen or Oxygen could come down to cost when cutting thicker material, with Nitrogen possibly being more expensive per hour than Oxygen, so the decision to use one over the other would come down to the site when comparing the application thickness, cutting finish, possible additional clean edge process and price of the cutting gas.
Plasma Cutting Aluminium with Nitrogen
Using Nitrogen for cutting aluminium produces an excellent cutting edge on the material as it reduces Oxidation during the cutting process. Again, costs of additional processes to clean up the cutting edge on the material is not required and can be considered a very suitable cutting gas.
Using Nitrogen-Assisted Laser Cutting
Nitrogen-assisted laser cutting is suitable for a wide range of applications.