What is the most common inert gas used when TIG welding stainless steel?

Argon is the most common inert gas used when TIG welding stainless steel due to its excellent shielding properties. TIG welding, or Tungsten Inert Gas welding, relies on the effective protection of the weld pool from atmospheric contamination that can occur during the welding process. Argon is preferred because it is denser than air, which creates a stable shield that prevents oxygen and nitrogen from entering the weld pool.

This is particularly important when working with stainless steel, as these materials can easily become discolored or weakened if exposed to reactive gases like oxygen during welding. Argon creates a clean inert atmosphere, resulting in high-quality welds with minimal oxidation and contamination. Its effectiveness and availability make it the standard choice for welding a variety of metals, including stainless steel, over other gases that might not offer the same level of protection or are more suited for different applications.