Restoration of Steam Turbine Last Stage Rotor Blades by Laser Surfacing

Abstract

Technology is provided for restoring erosion damaged rotor blades of the last stages of steam turbine low-pressure cylinders (LPC) using laser-powder surfacing and application of an erosion-resistant coating. For this method there is typically low heat input into the blade basic metal, which improves its restoration reliability. Results are obtained for comprehensive experimental studies on specimens and blades, confirming the high quality of welded joints obtained by laser surfacing of nickel alloy proposed for restoring the blade profile of blade steels ÉI961-Sh and 15Kh11MF-Sh, and application of a stellite-6 erosion-resistant coating. The possibility is concluded of using the laser-powder surfacing method during refurbishment of steam turbine LPC rotor blades.