| WO 2004/101209 A1 (11/25/04) Alstom Technology Ltd
"Balbach, W. M.; Keller, S."
METHOD FOR WELDING TOGETHER STRUCTURAL COMPONENTS AND ROTOR PRODUCED ACCORDING TO SAID METHOD
"A method for welding a nickel, nickel/iron or cobalt base superalloy to a high-alloy, high-temperature steel, by friction welding, a high-temperature steel intermediary to the surface of the first component using compressive force and simultaneously rotating the intermediary. The first component with the intermediary is then welded to the second component."