Abstract: The heavy steam and water corrosion of low pressure flow passage of 1000MW turbogenerator set in Huadian International Zouxian Power Plant was found in first inspection overhaul. The material of low pressure flow passage and its operation condition were analyzed, and the condition of low pressure passage was compared with that of subcritical turbine low pressure passage made using same material and the corrosion was not occurred here. The reason of the corrosion was found, and relevant measures and suggestions were put forward.

Key words: ultra-supercritical unit, low pressure flow passage, steam and water corrosion