Effect of annealing temperature on the corrosion behavior of duplex stainless steel studied by in situ techniques

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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In-situ duplex structure formation and high tensile strength of super duplex stainless steel produced by directed laser deposition

Materials Science and Engineering A ◽

10.1016/j.msea.2021.142557 ◽

2021 ◽

pp. 142557

Author(s):

Derui Jiang ◽

Xiang Gao ◽

Yuman Zhu ◽

Christopher Hutchinson ◽

Aijun Huang

Keyword(s):

Tensile Strength ◽

Stainless Steel ◽

Duplex Stainless Steel ◽

Structure Formation ◽

Laser Deposition ◽

Super Duplex Stainless Steel ◽

Duplex Structure ◽

High Tensile Strength

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Effects of heating and cooling rates on δ↔γ phase transformations in duplex stainless steel by in situ observation

Ironmaking & Steelmaking ◽

10.1080/03019233.2017.1370232 ◽

2017 ◽

Vol 46 (3) ◽

pp. 277-284 ◽

Cited By ~ 1

Author(s):

Yanhui Sun ◽

Yong Zhao ◽

Xiaobin Li ◽

Shuai Jiao

Keyword(s):

Stainless Steel ◽

Phase Transformations ◽

Duplex Stainless Steel ◽

In Situ Observation ◽

Cooling Rates ◽

Heating And Cooling

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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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