TY - JOUR
T1 - Influence of surface martensite layer on hydrogen embrittlement of Fe-Mn-C-Mo steels in wet H2S environment
AU - Li, Shihan
AU - Chen, Changfeng
AU - Liu, Yinong
AU - Yu, Haobo
AU - Wang, Xiaolin
PY - 2018/8/23
Y1 - 2018/8/23
N2 - This study investigated the effect of thermally induced surface martensite layer on hydrogen embrittlement of Fe-16Mn-0.4C-2Mo (wt.%) (16Mn) and Fe-25Mn-0.4C-2Mo (wt.%) (25Mn) steels through slow strain rate stress corrosion cracking testing and proof ring testing in wet H2S environment. The 16Mn steel had a surface layer of less than 150 μm in depth containing ε-martensite, α′-martensite and austenitic twins. The martensite layer is found to reduce the hydrogen embrittlement resistance of the steel. In comparison, the 25Mn steel developed a full α′-martensite surface layer, which exhibited practically nil effect on the hydrogen embrittlement resistance of the steel. The ε-martensite provides much larger interface areas with the mechanical twins of the austenite in the 16Mn steel than the α′-martensite/austenite interfaces in the 25Mn steel. These interfaces are hydrogen trapping sites and are prone to initiate surface cracks, as observed in the scanning electron microscope. The formation of the cracks is attributed to hydrogen concentration at the ε-martensite and austenitic twin interfaces, which accelerates material fracture.
AB - This study investigated the effect of thermally induced surface martensite layer on hydrogen embrittlement of Fe-16Mn-0.4C-2Mo (wt.%) (16Mn) and Fe-25Mn-0.4C-2Mo (wt.%) (25Mn) steels through slow strain rate stress corrosion cracking testing and proof ring testing in wet H2S environment. The 16Mn steel had a surface layer of less than 150 μm in depth containing ε-martensite, α′-martensite and austenitic twins. The martensite layer is found to reduce the hydrogen embrittlement resistance of the steel. In comparison, the 25Mn steel developed a full α′-martensite surface layer, which exhibited practically nil effect on the hydrogen embrittlement resistance of the steel. The ε-martensite provides much larger interface areas with the mechanical twins of the austenite in the 16Mn steel than the α′-martensite/austenite interfaces in the 25Mn steel. These interfaces are hydrogen trapping sites and are prone to initiate surface cracks, as observed in the scanning electron microscope. The formation of the cracks is attributed to hydrogen concentration at the ε-martensite and austenitic twin interfaces, which accelerates material fracture.
KW - Corrosion
KW - Hydrogen embrittlement
KW - Martensite
KW - Slow strain rate test
KW - TEM
KW - TWIP steels
UR - http://www.scopus.com/inward/record.url?scp=85050893571&partnerID=8YFLogxK
U2 - 10.1016/j.ijhydene.2018.06.011
DO - 10.1016/j.ijhydene.2018.06.011
M3 - Article
AN - SCOPUS:85050893571
VL - 43
SP - 16728
EP - 16736
JO - International Journal of Hydrogen Energy
JF - International Journal of Hydrogen Energy
SN - 0360-3199
IS - 34
ER -