Effect of Sensitizing Treatment on the Microstructure and Susceptibility to Intergranular Corrosion of High-Nitrogen Austenitic Stainless Steel

Abstract

This experiment investigated the effect of different sensitizing treatment times (2–48 h) at 800 °C on the microstructure and intergranular corrosion of high-nitrogen austenitic stainless steel by using scanning electron microscopy, energy-dispersive spectroscopy, double loop electrochemical potentiokinetic reactivation, and an oxalic acid etch test. The results indicate that with increasing sensitizing time, the austenite grains grew significantly and the carbide quantity began to increase at the grain boundary. The lamellar pearlite-like Cr2N was precipitated when the specimens were aged at 800 °C for 12 h. DL-EPR testing showed that IGC susceptibility of high-nitrogen austenitic stainless steel is mainly caused by the precipitation of carbide and increases when sensitization time is increased from 2 to 48 h.