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Behaviour of S31400 and S32205 steels in HCl‐ and H 2 S‐containing gas atmospheres under a low oxygen partial pressure between 480 and 680 °C
Author(s) -
Schmid Alexander,
Mori Gregor,
Haubner Roland,
Weil Matthias,
Hönig Stefan
Publication year - 2018
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.201709992
Subject(s) - corrosion , materials science , metallurgy , austenite , chromium , microstructure , ferrite (magnet) , oxide , hydrogen , partial pressure , chloride , oxygen , hydrogen chloride , inorganic chemistry , chemistry , composite material , organic chemistry
The effects of gaseous hydrogen chloride and hydrogen sulphide on the high‐temperature corrosion of the austenitic SS. S31400 and the duplex steel S32205 were investigated in an atmosphere without molecular O 2 . The testing gas atmosphere consisted of 3.8 vol% HCl, 1.9 vol% CO 2 , 0.3 vol% CO, 2.8 vol% H 2 , 0.02 vol% H 2 S, bal. N 2 . It showed a similar composition, which is present in the thermal cracking of anthropogenic resources. Tests were performed between 480 and 680 °C for 1, 3 and 10 days. Mass loss measurements were done for all experiments. After the reaction times the samples showed non‐adherent and porous layers of corrosion products, which were investigated by SEM/EDX and XRD. Metallographic cross sections of the corroded samples were prepared by water‐free polishing to investigate the microstructure of the corrosion products. Both materials formed large chromium sulphide crystals on top of a chromium oxide layer and a chlorine‐containing layer beneath the oxide. The ferrite phase of the duplex steel is selectively attacked, while the austenite phase remained without severe corrosion. Steel S31400 showed a uniform corrosion.