Gases

Gases

Gases have a decisive influence on the cutting quality. Depending on the material to be cut, certain gases or gas combinations are used. Every gas has its specific properties which can be used for cutting the different material grades. The following overview shows the gases that are typically used at Kjellberg Finsterwalde for each material type. Furthermore, it is necessary to define and distinguish the different gas types like ignition gas, plasma gas or swirl gas from one another.

 

 

Gases for Cutting Different Types of Materials

Material Plasma gas Swirl gas  
Mild steel O2 O2
Air
N2
  • Laser-like rectangularity of the cut surface
  • Smooth and dross-free surface
    		•
    Stainless steel N2/H2 N2
  • For thin stainless steel (CrNi) from 1 mm to 6 mm
    		•
      Ar/H2 N2
  • Good rectangularity of the cut surface
  • Smooth and dross-free surface
    		•
    Aluminium Air
    N2/H2    		 N2
  • For thin aluminium from 1 mm to 8 mm
    		•
      Ar/H2 N2
  • Nearly vertical cuts
    		•

    Properties and Purities of the Gases

    Gases have a great influence on the cut quality. In order to achieve an economic plasma process and optimum cut results it is imperative to use the right plasma-forming gases for the respective materials. The physical properties of the gases play a decisive role in this regard. Such important properties are ionization and dissociation energy, thermal conductivity, atomic weight and chemical reactivity.

    Gas Types

    Plasma gas (PG)

    Plasma gas (PG) means all gases or gas mixtures which can be used to generate the plasma beam and carry out the cutting process.

    Swirl gas (WG)

    Swirl gas (WG) covers the plasma beam. It helps to further increase the cut quality because it focusses and cools the arc additionally and protects the consumables during piercing and underwater cutting.

    Control gas (KG)

    The control gas (KG) is lead to the torch head and controls the presence of the protection cap which is situated there. It means that the machine can only be started when the torch is installed properly.