| Abstract: | In this paper, the use of Energy Dispersive Spectrometry (EDS) is proposed to determine the partition coefficients of the elements of a new family of duplex stainless steels that are characterized by having low contents of nickel, together with high levels of manganese and nitrogen. From the values of the partition coefficients, the chemical compositions of the constituting phases have been determined, in order subsequently to calculate the value of the Pitting Resistance Equivalent Number (PREN) of each phase. The proposition put forward in this study is that the phase having the lower PREN determines the pitting corrosion behaviour of these types of steels. Results obtained by means of optical and scanning electron microscopy have provided confirmation that the pitting corrosion behaviour of these new materials gets determined by the resistance of the weaker phase and consequently by the phase having the lower PREN value. Lastly it has been proved possible to determine the existence of an exponential relationship between the alloys pitting potential (Ep) and the weaker phase PREN; this can be utilized for the low‐nickel duplex stainless steels design in which the pitting corrosion resistance is controlled. |
