Carburization and metal dusting like attack of 9Cr-1Mo steel resulting from sulphide corrosion

Abstract

The influence of two sulphur-bearing refinery environments: (1) liquid hydrocarbons with steam present, and (2) liquid hydrocarbons with hydrogen present on the corrosion behaviour of commercial 9Cr-1Mo steel has been investigated. It has been stated that the progress of sulphide corrosion is followed by carburization of this steel due to the release of carbon from the sulphur-attacked metal carbides and the diffusion of carbon ahead of the advancing corrosion front. The rapid progress of sulphide corrosion with the presence of hydrogen results in a steep carbon concentration profile and metal dusting of the carburized layer. When metal dusting starts, rapid acceleration of scale growth and localised metal thinning takes place. © WILEY-VCH Verlag GmbH, 1999.