Plasma gas composition
Plasma gas composition determines the degree of ionization, enthalpy, and thermal power of the plasma. It directly affects cut quality and the tendency for oxidation of the cut faces.
Physicochemical Mechanism of Action
The plasma gas composition determines which gas types are active in the plasma. Active gases like argon or helium ionize easily and raise the plasma temperature. Inactive gases like nitrogen can bind oxygen and prevent oxidation.
Metallurgical Relevance & Welding Risks
An uneven gas composition can lead to irregular temperature distributions in the plasma, which hurts the cut quality. Excessive oxidation can lead to pore formation and reduced mechanical properties of the weld.
Workshop Practice & Instructions
Use a gas composition of 80% argon and 20% helium for good ionization and thermal performance. For fine metals like aluminum, a higher nitrogen content (up to 5%) can be used to reduce oxidation.