Erosion–corrosion behavior of SAF3207 hyper-duplex stainless steel

Abstract A new duplex 25Cr-3Ni-7Mn-0.66 N alloy was prepared in a vacuum arc re-melting furnace and characterized by metallographic and EPMA methods. Its corrosion behavior was investigated by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and a Mott-Schottky (M-S) analysis in artificial seawater at room temperature and compared with those of super and normal commercial duplex stainless steel (SDSS and DSS). No significant difference in the open circuit potentials and pitting potentials was observed. Its passive film current density lies between those of SDSS and DSS. This was confirmed by EIS analysis. A pit attack was observed on the δ-phase for all duplex samples, because the PREN16 of the δ-phase was lower than that of the γ-phase. From the Mott-Schottky analysis, the passive films were found to be composed of bi-layer structures, a p-type semiconductor inner layer, and a n-type semiconductor outer layer. The degree of defect as well as the effect of nitrogen in passive film layer are discussed with respect to the point defect model.

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Corrosion Behavior of Duplex Stainless Steel in Industrial White Liquor

CORROSION ◽

10.5006/2558 ◽

2017 ◽

Vol 74 (5) ◽

pp. 543-550 ◽

Cited By ~ 1

Author(s):

Luiza Esteves ◽

Mônica M.A.M. Schvartzman ◽

Wagner Reis da Costa Campos ◽

Vanessa F.C. Lins

Keyword(s):

Weight Loss ◽

Stainless Steel ◽

Corrosion Rate ◽

Duplex Stainless Steel ◽

Corrosion Behavior ◽

Extrapolation Method ◽

White Liquor ◽

Duplex Steel ◽

Kraft Mill ◽

Lower Corrosion Rate

Specimens of lean duplex and duplex stainless steel were exposed at 200°C in industrial white liquor from a Brazilian kraft mill using an autoclave to simulate the same conditions of digester processing. Tafel extrapolation method and weight loss were used to evaluate corrosion behavior of duplex steel in white liquor. The higher alloy steel, although presenting a lower corrosion rate than the lean duplex, presents a more severe selective attack on ferrite, at 200°C and 1.8 MPa, after Tafel extrapolation method in industrial white liquor.

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Influence of Molybdenum on Microstructure and Pitting Corrosion Behavior of Solution-Treated Duplex Stainless Steel in a Lithium Chloride Solution

Materials Research ◽

10.1590/1980-5373-mr-2019-0138 ◽

2019 ◽

Vol 22 (suppl 1) ◽

Author(s):

Stephania Cappellari de Rezende ◽

Isabela Dainezi ◽

Raíra Chefer Apolinario ◽

Lucíola Lucena de Sousa ◽

Neide Aparecida Mariano

Keyword(s):

Stainless Steel ◽

Duplex Stainless Steel ◽

Corrosion Behavior ◽

Lithium Chloride ◽

Pitting Corrosion ◽

Chloride Solution ◽

Solution Treated ◽

Lithium Chloride Solution

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Effects of the Treating Time on Microstructure and Erosion Corrosion Behavior of Salt-Bath-Nitrided 17-4PH Stainless Steel

Metallurgical and Materials Transactions B ◽

10.1007/s11663-013-9841-9 ◽

2013 ◽

Vol 44 (4) ◽

pp. 1010-1016 ◽

Cited By ~ 13

Author(s):

Jun Wang ◽

Yuanhua Lin ◽

Mingxing Li ◽

Hongyuan Fan ◽

Dezhi Zeng ◽

...

Keyword(s):

Stainless Steel ◽

Corrosion Behavior ◽

Salt Bath ◽

Erosion Corrosion

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Investigation of mechanical and corrosion behavior of laser hybrid weld joint of 2205 duplex stainless steel

Anti-Corrosion Methods and Materials ◽

10.1108/acmm-03-2021-2453 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Chuanbo Zheng ◽

Cheng Zhang ◽

Xiao Yong Wang ◽

Jie Gu

Keyword(s):

Stainless Steel ◽

Corrosion Resistance ◽

Duplex Stainless Steel ◽

Base Metal ◽

Corrosion Behavior ◽

Welded Joints ◽

Two Phase ◽

Content Type ◽

2205 Duplex Stainless Steel ◽

Laser Hybrid

Purpose Duplex stainless steel is composed of equal amounts of austenite and ferrite, which has excellent corrosion resistance and strength. However, after the metal was welded, the ratio of austenite and ferrite in the joint is unbalanced, and secondary phase precipitates are produced, which is also an important cause of pitting corrosion in the joint. Design/methodology/approach This paper aims to study the mechanical and corrosion behavior of welded joints, by adjusting the welding parameters of laser hybrid welding, dual heat sources are used to weld 2205 duplex stainless steel. The two-phase content of different parts of the welded joint is measured to study the influence of the ratio of the two-phase on the mechanical and corrosion properties of the joint. Findings The ratio of austenite and ferrite in different welded joints has an obvious difference, and from top to bottom, the austenite content decreased gradually, and the ferrite content increased gradually. The harmful phases are precipitated in the middle and lower part of the joint. The strength of welded joints is slightly lower than that of base metal. At the same time, the fracture analysis shows that some ferrite phases are affected by the precipitate in the grain and produce quasi-cleavage fracture. The corrosion results show that the corrosion resistance of the welded joints is lower than that of the base metal, and the concentration of chloride ions affects the corrosion resistance. Originality/value In this paper, the authors use the influence of different welding processes on the two-phase ratio of the joint to further study the influence of the microstructure on the corrosion resistance and mechanical properties of the weld.

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Erosion-Corrosion Protection Due to Cr3C2-NiCr Cermet Coating on Stainless Steel

Coatings ◽

10.3390/coatings10111042 ◽

2020 ◽

Vol 10 (11) ◽

pp. 1042

Author(s):

Panneer Selvam Kevin ◽

Abhishek Tiwari ◽

Saravanan Seman ◽

Syed Ali Beer Mohamed ◽

Rengaswamy Jayaganthan

Keyword(s):

Stainless Steel ◽

Corrosion Resistance ◽

Corrosion Behavior ◽

Potentiodynamic Polarization ◽

Electrochemical Impedance ◽

Turbine Blades ◽

Continuous Exposure ◽

Hydro Power ◽

Cermet Coating ◽

Erosion Corrosion

Cr3C2–NiCr coatings have been used extensively to combat the erosion corrosion of hydro power turbine blades made of stainless steel. Cr3C2–NiCr coatings are also used in aqueous corrosive environments due to the high corrosion resistance rendered by the NiCr binder. In this investigation, both erosion and corrosion environments are introduced to cermet coating to study corrosion behavior using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The cermet coatings are useful for reducing the risk of deterioration of mechanical properties of hydro power turbines due to the continuous exposure to the erosive and corrosive action of the corrosive environment containing silt. It was observed that Cr3C2–NiCr coating offered a reasonable improvement in corrosion resistance when compared to bare substrate. The corrosion behavior of the coating was studied in a 150 mL solution of 0.1 M NaCl with 2 gms of quartz particles (0.2–0.8 mm) at various rotation speeds (3000, 4500, 6000 rpm) of the solution over a 1 h immersion using potentiodynamic polarization and EIS studies in a specifically designed experimental set-up for erosion corrosion. When compared to the bare stainless steel samples at 3000 rpm and 6000 rpm, the coating showed the highest improvement at 6.57 times and the least improvement at 3.79 times, respectively.

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Investigation on the Corrosion Behavior of Lean Duplex Stainless Steel 2404 after Aging within the 650–850 °C Temperature Range

Metals ◽

10.3390/met9050529 ◽

2019 ◽

Vol 9 (5) ◽

pp. 529 ◽

Cited By ~ 5

Author(s):

Federica Zanotto ◽

Vincenzo Grassi ◽

Andrea Balbo ◽

Fabrizio Zucchi ◽

Cecilia Monticelli

Keyword(s):

Stainless Steel ◽

Grain Boundaries ◽

Duplex Stainless Steel ◽

Corrosion Behavior ◽

Thermal Aging ◽

Focused Ion Beam ◽

Ion Beam ◽

Localized Corrosion ◽

Fast Diffusion ◽

Lean Duplex Stainless Steel

This paper reports the effects of thermal aging between 650 and 850 °C on the localized corrosion behavior of lean duplex stainless steel (LDSS 2404). Critical pitting temperature (CPT) and double loop electrochemical potentiokinetic reactivation (DL-EPR) tests were performed. The localization of pitting attack and intergranular corrosion (IGC) attack after DL-EPR was investigated by optical (OM) and scanning electron microscopy (SEM) and by focused ion beam (FIB) coupled to SEM. Thermal aging caused the precipitation of mainly chromium nitrides at grain boundaries. Aging at 650 °C or short aging times (5 min) at 750 °C caused nitride precipitation mainly at α/α grain boundaries as a result of fast diffusion of chromium in this phase. Aging at 850 °C or aging times from 10 to 60 min at 750 °C also allowed the precipitation at the α/γ interface. Nitrides at γ/γ grain boundaries were observed rarely and only after long aging times (60 min) at 850 °C. Electrochemical tests showed that in as-received samples, pitting attack only affected the α phase. Conversely, in aged samples, pitting and IGC attack were detected close to nitrides in correspondence of α/α and α/γ grain boundaries depending on aging temperatures and times.

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