Comparative study of mechanical, corrosion and erosion-corrosion properties of cast hyper-duplex and super-duplex stainless steels
来源期刊：International Journal of Minerals Metallurgy and Materials2020年第7期
论文作者：P.Nithin Raj P.K.Navaneethkrishnan K.Sekar M.A.Joseph
文章页码：954 - 961
摘 要：Duplex stainless steels（DSSs） used in subsea structures and desalination industries require high corrosion and erosion resistance as well as excellent mechanical properties. The newly introduced cast duplex grade ASTM A890 7 A has a unique composition and is expected to have a much better resistance to corrosion and erosion compared with the super-duplex grades 5 A and 6 A. This work is a comparative study of the mechanical properties, corrosion, and erosion-corrosion resistance of super-duplex grades 5 A and 6 A and the hyper-duplex grade 7 A. The three DSSs exhibited equiaxial austenite islands in the ferrite matrix and balanced phase ratios. The hardness of the grade 7 A was nearly 15%higher than those of the super-duplex grades, which is attributed to the effect of the higher contents of W and Mn in 7 A. The impact toughness of grade 7 A was found to be lower than those of the super-duplex grades due to the carbide precipitation resulting from the partial substitution of Mo with W. The oxide layer strengthening effect of rare earth elements and the higher pitting resistance equivalent number（PREN） of grade7 A resulted in higher corrosion resistance. The harder and more passive grade 7 A showed a 35% lower material loss during erosion-corrosion.
P.Nithin Raj，P.K.Navaneethkrishnan，K.Sekar，M.A.Joseph
Department of Mechanical Engineering, National Institute of Technology
摘 要：Duplex stainless steels（DSSs） used in subsea structures and desalination industries require high corrosion and erosion resistance as well as excellent mechanical properties. The newly introduced cast duplex grade ASTM A890 7 A has a unique composition and is expected to have a much better resistance to corrosion and erosion compared with the super-duplex grades 5 A and 6 A. This work is a comparative study of the mechanical properties, corrosion, and erosion-corrosion resistance of super-duplex grades 5 A and 6 A and the hyper-duplex grade 7 A. The three DSSs exhibited equiaxial austenite islands in the ferrite matrix and balanced phase ratios. The hardness of the grade 7 A was nearly 15%higher than those of the super-duplex grades, which is attributed to the effect of the higher contents of W and Mn in 7 A. The impact toughness of grade 7 A was found to be lower than those of the super-duplex grades due to the carbide precipitation resulting from the partial substitution of Mo with W. The oxide layer strengthening effect of rare earth elements and the higher pitting resistance equivalent number（PREN） of grade7 A resulted in higher corrosion resistance. The harder and more passive grade 7 A showed a 35% lower material loss during erosion-corrosion.
关键词：
