Electrochemical Corrosion Study on Stainless Steel Used for Low-Pressure Steam Turbine Blades

Stainless steels, including ferritic-martensitic and precipitation-hardening stainless steel, find extensive utilization in low-pressure steam turbine blades for steam-powered energy generation plants. The failure of these blades often stems from fatigue originating in the pitting region due to corrosion attack, highlighting the importance of investigating the susceptibility of such incidents. This paper presents an investigation of pitting corrosion in stainless steel 410 and 17Cr4Ni alloy steel using electrochemical methods to probe the pitting behavior and assess the susceptibility of stainless steel to localized corrosion. The experimental setup involved exposing specimens to 1000 ppm sodium chloride (NaCl) solution and artificial seawater comprising three wt% NaCl and monitoring their electrochemical responses with linear polarization and cyclic voltammetry. The outcomes demonstrate that 17Cr4Ni exhibits superior corrosion resistance and passivation performances in three wt% NaCl content. However, it is noteworthy that the outcomes are comparably consistent when the specimens are exposed to a 1000 ppm NaCl environment.