Helium

Helium (He) is the second lightest process gas next to hydrogen. Colorless, odorless, tasteless, nontoxic and chemically inert, helium is nonflammable and, when compared with argon, has a high thermal conductivity. Helium-enhanced mixtures are utilized to create an inert gas shield and prevent oxidation during open arc welding of metals such as aluminum, stainless steel, copper and magnesium alloys. The addition of helium generally increases weld pool fluidity and travel speed. Penetration properties will be broader and travel speed is typically increased with the addition of helium to the shielding gas mixture. Use of helium-enhanced mixtures will also lessen the formation of welding ozone when welding on aluminum alloys.