Effect of Hydrostatic Pressure on the Pitting Corrosion Behavior of 316L Stainless Steel

The pitting corrosion behavior of 316L stainless steel (316L SS) was investigated by electrochemical measurements, nanoindentation and microscopy observation. The experiment results have been analyzed based upon the stochastic theory. Pitting initiation process has been modeled as anonhomogeneous Poisson process and analyzed using a Weibull distribution function. Pitting growth process has been simulated by a nonhomogeneous Markov process and analyzed using Gumbel distribution function. The analysis results revealed that hydrostatic pressure had three effects on the pitting corrosion behavior of 316L SS: (1) the increasing hydrostatic pressure enhance the mechanical properties of passive film; (2) the increasing hydrostatic pressure retarded the B1 process and accelerated the A3 process; (3) the pitting growth probability decreased with the increase of hydrostatic pressure. The above three factors led to the improvement of pitting corrosion resistance of 316L SS with the increasing of hydrostatic pressure.