AbstractThe localised corrosion behaviour of 17–4 PH (precipitation hardenable) stainless steel, in the solution annealed, aged, and overaged conditions, was studied in acidic chloride and sulphuric acid media using the potentiodynamic anodic polarisation method. Electrochemical potentiokinetic reactivation (EPR) studies and microstructural examination were also carried out. In the acidic chloride medium, the material in the solution annealed and overaged conditions corroded uniformly, whereas in the aged condition it exhibited passivity and pitting. In the sulphuric acid medium, the magnitude of anodic peaks changed significantly on varying the microstructural condition. The EPR charge and reactivation peak current density values, which were lower in the aged condition than in the solution annealed and overaged conditions, were in good agreement with the microstructural observations and results of polarisation studies.MST/1087