The pitting corrosion resistance of duplex stainless steels UNS S31803 annealed at different temperatures ranging from 1050 ℃ to 1200 ℃ for 24 h has been investigated by means of potentiostatic critical pitting temp...The pitting corrosion resistance of duplex stainless steels UNS S31803 annealed at different temperatures ranging from 1050 ℃ to 1200 ℃ for 24 h has been investigated by means of potentiostatic critical pitting temperature （CPT）. The microstructural evolution and pit morphologies of the specimens were studied through optical microscopy and scanning electron microscopy. The potentiostatic CPT measurements show that the CPT was elevated with the annealing temperature increased from 1050 ℃ to 1150℃ and decreased as the temperature further increased to 1200 ℃. The specimens annealed at 1150 ℃ exhibited the highest CPTand the best pitting corrosion resistance. The pit morphologies show that the pit initiation sites transfer from austenite phase to ferrite phase as the annealing temperature increases. The results were explained by the variation of pitting resistance equivalent number （PREN） of ferrite and austenite phases as the annealing temperature was varied.展开更多
Effects of Mo and Mn elements on pitting corrosion resistance of lean duplex stainless steel in C1- media solution have been studied. Gravimetric tests in 6 mass% FeCl3 at 35 ℃ and potentiodynamic analysis in 3.5 mas...Effects of Mo and Mn elements on pitting corrosion resistance of lean duplex stainless steel in C1- media solution have been studied. Gravimetric tests in 6 mass% FeCl3 at 35 ℃ and potentiodynamic analysis in 3.5 mass% NaCI were carried out. The corrosion potential （Ecoor） and the pitting potential （Epit） are shifted to a more noble po tential because of the presence of Mo around the pits. While the presence of Mn could sharply reduce the value of pitting resistance equivalent number （PREn） and the pits can be formed more easily. The pits are found generating at the phase with a lower PREn. The identical tendencies between the Epit and PREn of weaker phase are the same. A corrosion mechanism has been proposed to determinate pitting corrosion behavior based on microstructural observations.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.51131008 and 51371053)the National Key Technology R&D Program(No.2012BAE04B00)
文摘The pitting corrosion resistance of duplex stainless steels UNS S31803 annealed at different temperatures ranging from 1050 ℃ to 1200 ℃ for 24 h has been investigated by means of potentiostatic critical pitting temperature （CPT）. The microstructural evolution and pit morphologies of the specimens were studied through optical microscopy and scanning electron microscopy. The potentiostatic CPT measurements show that the CPT was elevated with the annealing temperature increased from 1050 ℃ to 1150℃ and decreased as the temperature further increased to 1200 ℃. The specimens annealed at 1150 ℃ exhibited the highest CPTand the best pitting corrosion resistance. The pit morphologies show that the pit initiation sites transfer from austenite phase to ferrite phase as the annealing temperature increases. The results were explained by the variation of pitting resistance equivalent number （PREN） of ferrite and austenite phases as the annealing temperature was varied.
文摘Effects of Mo and Mn elements on pitting corrosion resistance of lean duplex stainless steel in C1- media solution have been studied. Gravimetric tests in 6 mass% FeCl3 at 35 ℃ and potentiodynamic analysis in 3.5 mass% NaCI were carried out. The corrosion potential （Ecoor） and the pitting potential （Epit） are shifted to a more noble po tential because of the presence of Mo around the pits. While the presence of Mn could sharply reduce the value of pitting resistance equivalent number （PREn） and the pits can be formed more easily. The pits are found generating at the phase with a lower PREn. The identical tendencies between the Epit and PREn of weaker phase are the same. A corrosion mechanism has been proposed to determinate pitting corrosion behavior based on microstructural observations.
