Mechanisms and resistance to metal dusting in ferrous alloys
The metal dusting behavior of three ferrous alloys with varying Cr content (2.3%, 8.6%, and 20.1% by weight) has been studied in carbonaceous atmospheres where the activity of carbon is greater than 1. Failures due to metal dusting have been reported in petrochemical, chemical industries, nuclear reactors and solid oxide fuel cells. It is estimated that financial losses in hydrogen industry alone due to metal dusting related maintenance problems is estimated to be around $300 million annually. Two atmospheres with varying water vapor contents (23 and 2.3%) have been used for the study to understand the role of vapor during metal dusting. ^ Low Cr alloy, T22, showed extensive surface degradation and pitting, while increasing Cr content showed improved resistance to metal dusting for T91 (medium Cr) and 800 (high Cr) alloys due to the formation of protective Cr2O3 scales early during metal dusting. Resistance to metal dusting also improved in atmosphere with higher vapor content. Presence of high vapor content in the atmosphere favors the formation of protective Cr2O3 scales early during metal dusting and these scales not only delay the ingress of carbon into the alloy matrix but also offer resistance to carbon diffusion thus improving the overall resistance of the alloys against metal dusting. ^ A combination of high Cr content in the alloy and high vapor content in the atmosphere is favorable for formation of protective Cr2O 3 scales early during metal dusting and this improves the resistance of the alloys to metal dusting corrosion. ^
Engineering, Metallurgy|Engineering, Materials Science
Putrevu, Aditya, "Mechanisms and resistance to metal dusting in ferrous alloys" (2006). ETD Collection for University of Texas, El Paso. AAI1435301.