Revealing significant effect of nitrogen on prolonging pitting corrosion lifetime of martensitic stainless steel by modelling approach

The prediction models of pitting corrosion lifetime for martensitic stainless steels (MSSs) with different N contents were developed by statistical approach. The modelling and experimental results show that after N-alloying, the metastable pit initiation time was dramatically improved, and the transformation from metastable into stable pitting was retrained, which resulted in the increase of overall stable pit initiation time from 0 to 419.05 and 459.84 days with 0.15 and 0.41 wt% N addition, respectively. Afterwards, N significantly restrained the growth of stable pits. The present models reveal the mechanism of how N influences each stage of pitting corrosion. •Prediction models of pitting corrosion lifetime were established to reveal how N influences each stage of pitting corrosion.•N significantly prolonged the pitting corrosion lifetime of martensitic stainless steel.•N-alloying dramatically prolonged the pit initiation time and significantly restrained the growth of stable pits.