For which type of metals is argon-hydrogen mixtures used in GTAW?

Argon-hydrogen mixtures are primarily used in Gas Tungsten Arc Welding (GTAW, also known as TIG welding) for stainless steels due to several key reasons. The addition of hydrogen to the argon shielding gas enhances the heat of the arc, which is beneficial for achieving proper fusion and penetration when welding stainless steels.

Stainless steels often have higher thermal conductivity and heat dissipation properties compared to many other materials, requiring additional heat input to avoid issues such as poor weld quality or incomplete penetration. The argon-hydrogen mixture increases the arc stability and energy density, making it easier to handle the unique characteristics of stainless steels during the welding process.

Additionally, the presence of hydrogen can help improve the cleaning action at the weld pool, which is particularly useful for stainless steels that may have oxide films that need to be disrupted for effective bonding. This leads to greater weld integrity and enables better control over the mechanical properties of the final weld.

The other types of metals mentioned do not typically benefit from argon-hydrogen mixtures in the same way, making the use of this gas blend specific to stainless steels in the context of GTAW.