Evaluation of intergranular corrosion susceptibility of Super304H steel after being aged at 600°C

Abstract

Abstract The susceptibility to intergranular corrosion of as-received and 600°C aging-treated new austenite heat-resistance Super304H steel was investigated by double loop electrochemical potentiodynamic (EPR) test. Experimental results indicated that the as-received Super304H steel possesses lower tendency of intergranaular corrosion. With the increase of aging time, intergranular corrosion susceptibility of Super304H steel increases. Intergranular corrosion of Super304H steel occurs due to the precipitation of Cr23C6 along grain boundaries. At the initial stage of aging, the rapid precipitating behavior of Cr23C6 leads to the rapid increase of intergranlar corrosion susceptibility. The amount of Cr23C6 precipitates increases with the extension of aging time, and the intergranular corrosion susceptibility of Super304H steel increases accordingly. The extent of intergranular corrosion change is related to the precipitating rate of Cr23C6. ()