Metal dusting of low alloyed steels or Fe-Ni-Cr alloys has been reported in industrial environment working with strongly carburizing atmospheres at temperature from 450°C to 800°C. During this catastrophic form of carburization, the affected metal disintegrates into a mixture of powdery carbon and metal particles. In the present study, the corrosion behavior of alloy UNS N08810 (alloy 800H) tubes was investigated in H2 - 85% CO gas mixture at 650°C. The metal dusting is preceded by internal carburization whereby the chromium is tied up. Afterwards the remaining Fe-Ni matrix can react to the unstable intermediate carbide M3C which decomposes to metal particles and carbon. In order to detect the appearance of the damage, acoustic emission sensors were coupled with the tested material during the experiments. Thus, corrosion evolution and pit distribution were monitored on-line and correlated with acoustic parameters. We show in this paper that the introduction of organic
sulfides like dimethyl disulfur (DMDS) in the process gas produced a significant decrease in the corrosion phenomena. Keywords : metal dusting, acoustic emission, carburizing atmosphere, inhibition, dimethyl disulfur, alloy 800H, carburization, monitoring