Characterization and comparative analysis of corrosion resistance of 4 high manganese steels models in aqueous solution of NaCl

Abstract

The liquefied natural gas volumes that currently need to be stored and/or transported require engineering to consistently develop materials that combine high mechanical strength and low manufacturing costs. The present work brings the study of four models of high manganese steels (non-commercials), to demonstrate the feasibility of being used in the petrochemical industry. The tests contemplate the characterization (composition, phase diagram, metallography, EBSD, microhardness), corrosion resistance in NaCl solution (Open Circuit Potential, Linear Polarization) and characterization of corrosion products (EDS, SEM, Raman Spectroscopy). The obtained results showed a relationship between the increases of the manganese content with: formation of twins that help their hardening, as well as the decrease of their corrosion resistance; the steel with less amount of this element had a more noble behavior. Quantities of chromium, silicon and aluminum in these steels could not contain the high dissolution of manganese, which caused low stability of the formed oxides that allows the electrolyte ions to reach the metal surface, accelerating the dissolution process.