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Enhancing Effects of NaHSO3 on Corrosion of T91 Steel

  • Wu, Tangqing (Key Laboratory of Materials Design and Preparation Technology of Hunan Province, Xiangtan University) ;
  • Tan, Yao (Key Laboratory of Materials Design and Preparation Technology of Hunan Province, Xiangtan University) ;
  • Wang, Jun (Electric Power Research Institute, State Grid Hunan Electric Power Co. Ltd) ;
  • Xu, Song (Electric Power Research Institute, State Grid Hunan Electric Power Co. Ltd) ;
  • Liu, Lanlan (Maintenance Company, State Grid Hunan Electric Power Co. Ltd) ;
  • Feng, Chao (Electric Power Research Institute, State Grid Hunan Electric Power Co. Ltd) ;
  • Yin, Fucheng (Key Laboratory of Materials Design and Preparation Technology of Hunan Province, Xiangtan University)
  • Received : 2020.05.04
  • Accepted : 2020.06.22
  • Published : 2020.11.30

Abstract

In the paper, corrosion behavior of T91 steel in different concentrations of NaHSO3 solution was studied in combination with scanning electron microscope (SEM) and electrochemical measurements. The results showed that the steel exhibited active anodic dissolution characteristics in the solution, and NaHSO3 concentration affected both cathodic and anodic behaviors. The steel surface was covered by intact corrosion products in the solutions, but the compactness and mechanical properties of the corrosion products degraded with the increase of NaHSO3 concentration. In low-concentration NaHSO3 solution the steel tended to undergo uniform corrosion with slight corrosion pits, but its corrosion mode gradually transited to localized corrosion as the NaHSO3 concentration increased. The mechanical property degradation of the corrosion products caused by sulfur compounds and the pH decrease of the solution are the important factors to accelerating its corrosion process.