산성 염화물 환경에서 F53 슈퍼 듀플렉스 스테인리스강의 2 상간의 공식 거동 연구 (Investigation of the pitting corrosion behavior between the constituent phases in F53 super duplex stainless steel in acidified chloride environments)

서지정보

· 발행기관 : 한국부식방식학회
· 수록지 정보 : CORROSION SCIENCE AND TECHNOLOGY / 13권 / 3호 / 95 ~ 101페이지
· 저자명 : 김순태, 공경호, 이인성, 박용수, 이종훈, 김두현

초록

The pitting corrosion behaviors between the constituent phases in F53 super duplex stainless steel (SDSS)in acidified chloride environments were investigated using a critical pitting corrosion temperature test, apotentiodynamic anodic polarization test, and the microstructure analyses through a SEM-EDS and a SAM.
As the solution annealing temperature decreased from 1150℃ to 1050℃, the γ-phase fraction increasedwhereas the α-phase fraction decreased. The pitting potential and the critical pitting temperature increasedwith a decrease of solution annealing temperature, thereby increasing the resistance to pitting corrosion.
The pitting corrosion of the SDSS was selectively initiated at the α-phases because the PREN (pitting resistanceequivalent number, PREN = %Cr+3.3%Mo+30%N) value of the γ-phase is much larger than that of theα-phase, irrespective of the solution annealing temperature. The pitting corrosion was finally propagatedfrom the α-phase to the γ-phase. The decrease of solution annealing temperature enhanced the resistanceto pitting corrosion greatly in acidified chloride environments due to a decrease of PREN difference betweenthe γ-phase and the α-phase, that is, a decrease of PRENγ by dilution of N in γ-phase with an increasein the γ-phase volume fraction and an increase of PRENα by enrichment of Cr and Mo in the α-phasewith a decrease in the α-phase volume fraction.

영어초록

The pitting corrosion behaviors between the constituent phases in F53 super duplex stainless steel (SDSS)in acidified chloride environments were investigated using a critical pitting corrosion temperature test, apotentiodynamic anodic polarization test, and the microstructure analyses through a SEM-EDS and a SAM.
As the solution annealing temperature decreased from 1150℃ to 1050℃, the γ-phase fraction increasedwhereas the α-phase fraction decreased. The pitting potential and the critical pitting temperature increasedwith a decrease of solution annealing temperature, thereby increasing the resistance to pitting corrosion.
The pitting corrosion of the SDSS was selectively initiated at the α-phases because the PREN (pitting resistanceequivalent number, PREN = %Cr+3.3%Mo+30%N) value of the γ-phase is much larger than that of theα-phase, irrespective of the solution annealing temperature. The pitting corrosion was finally propagatedfrom the α-phase to the γ-phase. The decrease of solution annealing temperature enhanced the resistanceto pitting corrosion greatly in acidified chloride environments due to a decrease of PREN difference betweenthe γ-phase and the α-phase, that is, a decrease of PRENγ by dilution of N in γ-phase with an increasein the γ-phase volume fraction and an increase of PRENα by enrichment of Cr and Mo in the α-phasewith a decrease in the α-phase volume fraction.

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