Role of Nitrogen in the Pitting Resistance of Cast Duplex CF-Type Stainless Steels

Abstract

In this investigation, critical manipulation, observation, and analysis of polarization curves as a function of nitrogen content in cast duplex CF-type stainless steels (SSs) has been performed. These, in conjunction with microstructural observations and atomic absorption spectroscopic analyses of polarization cell solutions, have led to the discovery of nitrogen’s major role in the corrosion resistance of SSs. Nitrogen has been found to encourage the retention of chromium in the passive film and near surface layers during corrosion, which improves pitting resistance.