Application of bipolar electrochemistry to assess the corrosion resistance of solution annealed lean duplex stainless steel

•Lean duplex stainless steel was heat treated at 1000℃ to 1350℃.•Pit nucleation and growth kinetics were obtained at room temperature.•Heat treatments at 1000℃ had the highest pitting corrosion resistance.•A new microstructure design containing isolated small ferrite grains is proposed.