Copper wire: copper and copper alloy welding wire is commonly used in the welding of copper and copper alloys, including brass wire is also widely used for brazing carbon steel, cast iron and carbide cutting tools. Aluminum welding wire: aluminum and aluminum alloy wire for aluminum welding and oxygen - acetylene gas welding for the filling material. That can only weld aluminum. Stainless steel welding wire Welded stainless steel and wire components are basically the same, weldable chromium stainless steel, chromium - nickel stainless steel, ultra-low carbon stainless steel, dissimilar steel.