Corrosion performance of types 310S and 410 stainless steels in forming gas containing 1% H2S or 1% H2S/1% HCl at 600°C

The corrosion of types 310S and 410 stainless steels in forming gas containing 1%H2S or 1%H2S/1%HCl has been studied at 600°C. In the conditions chosen, sulphide scales formed on both materials and significant differences in corrosion rate and depth of attack were observed. Thermogravimetric results showed that for both materials there was an initial transient period of rapid sulphidation after which linear or parabolic kinetics were observed. Type 310S and 410 both developed non-adherent, multi-layered sulphide corrosion products. Scanning electron microscopy, energy dispersive X-ray analysis and X-ray diffraction were used to examine the structure and composition of these sulphide scales. The differences in corrosion morphology are in agreement with the variations in the thermogravimetric experiments. Mechanistic corrosion models are being developed.