Effect of Heat Treatment on the Corrosion Behavior of a Supermartensitic Stainless Steel in Sour Solution.

In the present research work, the influence of heat treatment on the corrosion behavior of a supermartensitic stainless steel (SMSS) in sour solution (H2S gas was replaced by sodium thiosulfate) was studied using polarization curve electrochemical techniques (CP) and Electrochemical Impedance Spectroscopy (EIS), along with microstructural characterization using optical microscopy and X-ray diffraction (XRD) measurements. The CP results revealed that the samples subjected to quenching and tempering process exhibited the formation of a more protective corrosion product layer. However, the EIS results showed that this layer accelerated the corrosion process as immersion time increased. Finally, according to XRD and electrochemical test results, the lower the percentage of volume fraction of retained austenite in the microstructure of SMSS, the lower the corrosion resistance.