Effects of Rare Earth Metals addition and aging treatment on the corrosion resistance and mechanical properties of super duplex stainless steels

2002 ◽  
Vol 8 (3) ◽  
pp. 309-318 ◽  
Author(s):  
Yong-Soo Park ◽  
Soon-Tae Kim ◽  
In-Sung Lee ◽  
Chi-Bok Song
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Rare Earth ◽  
Stainless Steels ◽  
Rare Earth Metals ◽  
Aging Treatment ◽  
Duplex Stainless Steels ◽  
Super Duplex Stainless Steels

Effects of Heat Input Conditions on the Local Thermophysical Properties of Super Duplex Stainless Steels

2018 ◽  
Vol 930 ◽  
pp. 317-321
Author(s):  
José Adilson de Castro ◽  
Gláucio Soares da Fonseca ◽  
D.S.S. Almeida ◽  
L.C.R. Lopes ◽  
C.R. Xavier ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Mechanical Strength ◽  
Stainless Steels ◽  
Thermal History ◽  
Duplex Stainless Steels ◽  
Measured Temperature ◽  
Sem Images ◽  
Super Duplex Stainless Steels ◽  
Welding Procedure

The thermal properties of the super duplex stainless steels are strongly affected by the thermal history when welding procedure are applied leading to substantial changes on the mechanical properties of the welding region. The controlled dual phase microstructure (ferrite and austenite) guarantee excellent mechanical properties such as mechanical strength and corrosion resistance, in addition to small thermal expansion coefficient and high thermal conductivity. In this research a model able to predict the thermal history of the welding pieces coupled with local mechanical properties developed during welding procedure is developed. The model was verified by measured temperature profile and used to predict local properties such as grain size evolution, hardness and mechanical strength. An inverse method was implemented to obtain the parameters fitting for the grain growth evolution, hardness and yielding strength compatible with the final microstructure and grain size measured using SEM images and stereological techniques.

scholarly journals Use of the Critical Acidification Model to Estimate the Influence of W in the Localized Corrosion Resistance of 25Cr Super Duplex Stainless Steels

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1364
Author(s):  
Cristian Torres ◽  
Mariano Iannuzzi ◽  
Roy Johnsen
Keyword(s):  
Corrosion Resistance ◽  
Stainless Steels ◽  
Potentiodynamic Polarization ◽  
Ph Value ◽  
Sem Analysis ◽  
Duplex Stainless Steels ◽  
Localized Corrosion ◽  
Significant Difference ◽  
Super Duplex Stainless Steels ◽  
Acidification Model

Two super duplex stainless steels (SDSS) with different W content, namely UNS S32750 (W-free) and UNS S39274 (2.1 wt.% W), were tested in simulated crevice corrosion environments to determine the influence of W on their corrosion resistance. Anodic potentiodynamic polarization experiments were performed in two different crevice-like-solutions: 1 M HCl (as reference for a pH = 0 environment), and 7 M LiCl, adjusted to the same pH value. Galvele’s critical acidification model was used to estimate the theoretical critical potential (Ecrit) and comparatively evaluate the corrosion resistance of the two SDSS. The anodic potentiodynamic polarization results showed a statistically significant difference between the two materials in only one test condition, i.e., 7 M Cl− at 60 °C. Additionally, the quantification of chemical dissolution of the metal cations after the tests suggested a surface enrichment in W only in the 7 M chloride solution. Scanning electron microscope (SEM) analysis indicated a uniform dissolution experienced by UNS S32750 in this environment, whereas UNS S39274 suffered selective corrosion of the ferrite-phase. These observations were reflected in a slight increase in the Ecrit values of UNS S32974 estimated with Galvele’s model.

Compatibility Evaluation for Application of Lean Duplex Stainless Steels to Seawater Systems in Nuclear Power Plants

2010 ◽  
Vol 654-656 ◽  
pp. 382-385
Author(s):  
Hyun Young Chang ◽  
Heung Bae Park ◽  
Young Sik Kim ◽  
Sang Kon Ahn ◽  
Kwang Tae Kim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Stainless Steels ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
High Strength ◽  
Duplex Stainless Steels ◽  
Stainless Steel 316L ◽  
Pitting Potential

Lean duplex stainless steels have been developed in Korea for the purpose of being used in the seawater systems of industries. The flow velocity of some part of seawater systems in nuclear power plants is high and damages of components from corrosion are severe. Therefore, this environment requires using high strength and high corrosion resistant steels. The newly developed lean duplex stainless steels STS329LD(20.3Cr-2.2Ni-1.4Mo) and STS329J3L(22.4Cr-5.7Ni-3.6Mo) are evaluated for the compatibility in seawater systems of nuclear power plants. In this study, the physical & mechanical properties and corrosion resistance of two alloys were quantitatively evaluated in comparison with commercial stainless steel 316L. Microstructures and mechanical properties of them were analyzed and the electrochemical properties related to corrosion resistance were measured such as pitting potential, passive current density, and corrosion rates from Tafel analysis. Critical pitting temperatures were measured in accordance with ASTM G48E method. The pitting initiation time and lifetime for replacement were predicted from the PRE values of test alloys and empirical equations that have been formulated from the condenser tubes of a nuclear power plant.

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