The corrosion of AISI 310 stainless steel exposed to sulphidizing/oxidizing/carburizing atmospheres at 600°C

Abstract

AISI 310 is one of the iron-based austenitic steels most commonly used for high temperature components in industrial engineering plants. The alloy, containing 25% Cr and 20% Ni, relies upon the formation and maintenance of a thin adherent surface chromia layer for protection against severe corrosive attack. The alloy's performance in purely oxidizing environments is well established but its behaviour in multi-component atmospheres, particularly those containing sulphidizing species, is less well documented. In the gasification of coal for the subsequent production of electricity using steam or gas turbines, component corrosion can pose significant problems. The work described in this paper was carried out at 600°C in H 2-based gas mixtures with constant oxygen partial pressure ( pO 2 = 10 −26 bar) and carbon activity ( a c = 0.2), but with different levels of sulphur. Sulphur partial pressures, typical of those found in coal gasifiers ( pS 2 = 10 −11 to 10 −9 bar), were achieved by making H 2S additions of 0.4-1.0%. Corrosion behaviour for exposures up to 1000 h was investigated using weight changes and a range of electron-optical structural analysis techniques. The influence of sulphur partial pressure on scaling kinetics is quantified and scaling mechanisms are identified.