The intergranular corrosion of the weld metal of super Type 304H (UNS S30409) stainless steel during aging at 650°C was investigated using electrochemical potentiokinetic reactivation (EPR). Experimental results showed that the as-welded weld joint possesses a good corrosion-resistant property, but the formation of chromium-depleted zones caused by precipitation of Cr23C6 between cellular dendrites increased the reactivation ratio (Ra) when the weld metal was aged at 650°C for a prolonged time, indicating the acceleration of intergranular corrosion with increased aging time. Nevertheless, it was found that Cr23C6 showed the morphology with isolated particles after being aged for 500 h and Ra became stable.

Subject
Scanning electron microscopy, X-ray diffraction, Precipitation (solids), Microstructure, Precipitates, Transmission electron microscopy, Welding, Steel, Grain boundary, Intergranular corrosion, Grain, Weld metal, Aging
Keywords:
aging treatment, electrochemical potentiokinetic reactivation, intergranular corrosion, super Type 304H steel, weld metal
© 2012 NACE International
2012
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