scholarly journals EFFECT OF SIGMA PHASE PRECIPITATION ON MECHANICAL BEHAVIOR AND PITTING CORROSION OF DUPLEX STAINLESS STEEL

2019 ◽  
Vol 25 (1) ◽  
pp. 4
Author(s):  
Talha Berguiga ◽  
Zakaria Boumerzoug
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Pitting Corrosion ◽  
Sigma Phase ◽  
Produced Water ◽  
Water Solution ◽  
Chloride Concentration ◽  
Corrosion Properties ◽  
Pitting Potential ◽  
Simulated Seawater

<p class="Style1">The main purpose of this work is to investigate the pitting corrosion behavior of sigmatized duplex stainless steel (DSS) exposed to two different chloride environments: simulated seawater solution and produced water solution. Specimens taken from a commercial DSS (UNS 31803) have been subjected to aging treatments at 850°C for different holding times to achieve different amounts of sigma phase. Metallographic examinations combined with X-ray diffraction technique were employed to follow the microstructure evolution. The pitting potential of the aged samples were determined in simulated seawater solution and produced water solution. It was established that solution treated DSS shows a high pitting corrosion resistance in both test solutions, while serious deterioration of corrosion properties occurs in presence of sigma phase. It was concluded that both sigma phase amount and chloride concentration worsen the pitting potential, the higher sigma content, the lower pitting potential and the higher chloride concentration, the lower pitting potential. SEM observation showed that pitting nucleation occurs preferentially at sigma phase interfaces due to the development of Cr- and Mo-depleted regions around sigma phase. It was also confirmed that the hardness behavior is only affected for long term aged samples.</p><p class="Style1"> </p>

scholarly journals EFFECT OF SIGMA PHASE PRECIPITATION ON MECHANICAL BEHAVIOR AND PITTING CORROSION OF DUPLEX STAINLESS STEEL

2021 ◽  
Vol 25 (1) ◽  
pp. 4-17
Author(s):  
Talha Berguiga ◽  
Zakaria Boumerzoug
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Pitting Corrosion ◽  
Sigma Phase ◽  
Produced Water ◽  
Water Solution ◽  
Chloride Concentration ◽  
Corrosion Properties ◽  
Pitting Potential ◽  
Simulated Seawater

The main purpose of this work is to investigate the pitting corrosion behavior of sigmatized duplex stainless steel (DSS) exposed to two different chloride environments: simulated seawater solution and produced water solution. Specimens taken from a commercial DSS (UNS 31803) have been subjected to aging treatments at 850°C for different holding times to achieve different amounts of sigma phase. Metallographic examinations combined with X-ray diffraction technique were employed to follow the microstructure evolution. The pitting potential of the aged samples were determined in simulated seawater solution and produced water solution. It was established that solution treated DSS shows a high pitting corrosion resistance in both test solutions, while serious deterioration of corrosion properties occurs in presence of sigma phase. It was concluded that both sigma phase amount and chloride concentration worsen the pitting potential, the higher sigma content, the lower pitting potential and the higher chloride concentration, the lower pitting potential. SEM observation showed that pitting nucleation occurs preferentially at sigma phase interfaces due to the development of Cr- and Mo-depleted regions around sigma phase. It was also confirmed that the hardness behavior is only affected for long term aged samples.

Influence of Sigma Phase Precipitation on Pitting Corrosion of 2507 Super-Duplex Stainless Steel

2010 ◽  
Vol 658 ◽  
pp. 380-383 ◽  
Author(s):  
Ying Han ◽  
De Ning Zou ◽  
Wei Zhang ◽  
Jun Hui Yu ◽  
Yuan Yuan Qiao
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Ambient Temperature ◽  
Duplex Stainless Steel ◽  
Pitting Corrosion ◽  
Super Duplex Stainless Steel ◽  
Phase Precipitation ◽  
Pitting Potential ◽  
Σ Phase ◽  
Pitting Corrosion Resistance

Specimens of 2507 super-duplex stainless steel aging at 850°C for 5 min, 15 min and 60 min were investigated to evaluate the pitting corrosion resistance in 3.5% NaCl solution at 30°C and 50°C. The results are correlated with the microstructures obtained with different aging time. The precipitation of σ phase remarkably decreases the pitting corrosion resistance of the steel and the specimen aged for 60 min presents the lowest pitting potential at both 30°C and 50°C. With increasing the ambient temperature from 30°C to 50°C, the pitting potential exhibits a reduction tendency, while this tendency is less obviously in enhancing the ambient temperature than in extending the isothermal aging duration from 5 to 60 min. SEM analysis shows that the surrounding regions of σ phase are the preferable sites for the formation of corrosion pits which grew up subsequently. This may be attributed to the lower content of corrosion resistance elements in these regions formatted with σ phase precipitation.

scholarly journals Pitting Corrosion Resistance on Annealing Treated Super Duplex Stainless Steel S32750

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 294
Author(s):  
Shuang Liu ◽  
Chaohua Yue ◽  
Xi Chen ◽  
Qiuhua Zhu ◽  
Yiyou Tu
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Duplex Stainless Steel ◽  
Pitting Corrosion ◽  
Annealing Temperature ◽  
Super Duplex Stainless Steel ◽  
Boundary Area ◽  
Pitting Potential ◽  
Pitting Corrosion Resistance ◽  
Equivalent Number

The pitting corrosion resistance of S32750 super duplex stainless steel, annealing treated at temperatures of 950–1200 °C for 20–60 min, was investigated using potentiodynamic polarization tests. The results show that the volume fractions of ferrite in the S32750 duplex stainless steel increased from 48.9% to 68.4% as annealing temperatures increased from 950 to 1200 °C. The pitting potential of the sample increased first and then decreased from an annealing temperature of 950 to 1050 °C, and the highest pitting potential was observed after annealing at 1050 °C for 35 min. The pitting corrosion resistance of S32750 stainless steel is due to the combination of pitting resistance equivalent number (PREN) value, phase fraction and grain boundary area fraction, and the imbalance of corrosion potential.

Pitting corrosion and effect of Euphorbia echinus extract on the corrosion behavior of AISI 321 stainless steel in chlorinated acid

2019 ◽  
Vol 37 (3) ◽  
pp. 259-271 ◽  
Author(s):  
Y. Koumya ◽  
R. Idouhli ◽  
M. Khadiri ◽  
A. Abouelfida ◽  
A. Aityoub ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Pitting Corrosion ◽  
Electrochemical Impedance ◽  
Chloride Concentration ◽  
Analysis Data ◽  
Chloride Ions ◽  
General Corrosion ◽  
Visible Absorption ◽  
Pitting Potential ◽  
Aisi 321

AbstractStainless steel (SS) is a very corrosion-resistant alloy used in different industrial plants because of its chemical and mechanical properties. However, the high chloride concentration in sulfuric acid (H2SO4) may promote both general corrosion and pitting corrosion. The pitting corrosion susceptibility in SS in chlorinated H2SO4 and the effect of Euphorbia echinus extract (EEE) on both general corrosion and pitting corrosion have been studied using potentiodynamic polarization, electrochemical impedance spectroscopy, chronoamperometry, cyclic voltammetry, and scanning electron microscopy (SEM). The pitting potential has been found to shift slightly in the presence of chloride ions (Cl−) in H2SO4. Also, pitting corrosion initiation has been demonstrated in the recorded chronoamperograms as a linear straight line having a positive slope. EEE has reduced the general corrosion and the inhibitor adsorption was found to follow the Langmuir isotherm. SEM micrographs showed that the tested inhibitor has efficiently acted on pitting corrosion for different concentrations of Cl−. Also, the kinetic findings were in good agreement with the surface analysis data. Fourier transform infrared spectroscopy and ultraviolet-visible absorption spectrophotometric measurements provided more insights on the interaction between the chemical functional groups of the inhibitor and the SS surface.

Influence of Sigma Phase Formation on Pitting Corrosion of an Aged UNS S31803 Duplex Stainless Steel

CORROSION ◽  
10.5006/0768 ◽  
2013 ◽  
Vol 69 (9) ◽  
pp. 900-911 ◽  
Author(s):  
Daniella Caluscio dos Santos ◽  
Rodrigo Magnabosco ◽  
Carlos de Moura-Neto
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Phase Formation ◽  
Pitting Corrosion ◽  
Sigma Phase

Microstructural influence of sigma phase on pitting corrosion behavior of duplex stainless steel/NaCl electrolyte couple

2021 ◽  
Vol 259 ◽  
pp. 124056 ◽  
Author(s):  
David D.S. Silva ◽  
Thiago A. Simões ◽  
Daniel A. Macedo ◽  
Alysson H.S. Bueno ◽  
Sandro M. Torres ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Corrosion Behavior ◽  
Pitting Corrosion ◽  
Sigma Phase

Macro and Micro Electrochemical Techniques to Study Influence of Sigma Phase Formation in a Duplex Stainless Steel

2013 ◽  
Vol 794 ◽  
pp. 583-591 ◽  
Author(s):  
B. Sunil Kumar ◽  
Vivekanand Kain
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Pitting Corrosion ◽  
Potentiodynamic Polarization ◽  
Sigma Phase ◽  
Electrochemical Techniques ◽  
Chloride Ion ◽  
Heat Treatments ◽  
Localized Corrosion ◽  
Chromium Depletion

In the present study macro electrochemical (anodic polarization) and micro electrochemical (scanning electrochemical microscopy (SECM) area scan measurements at passive potential) techniques have been used to study the influence of sigma phase and/or the resultant chromium depletion regions on localized corrosion behavior of aged type 2205 duplex stainless steel (DSS) in neutral chloride ion solution. DSS type 2205 was subjected to aging at 750 °C for 30 min, 10 h and 48 h. The formation and growth of the sigma phase with heat treatments was assessed by optical microscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction. The influence of formation of sub-microscopic and bulky sigma phase on intergranular corrosion (IGC) and pitting corrosion was investigated by various electrochemical techniques including electrochemical potentiokinetic reactivation (EPR), potentiodynamic polarization and SECM. Apart from EPR tests, ASTM A 262 Practice B test was carried out to evaluate the presence of chromium depletion regions with heat treatments. The results showed that with increasing aging duration, the degree of sensitization and IGC rates initially increased and then decreased with heat treatment. The pitting potentials decreased continuously with increase in aging duration up to 10 h as assessed by potentiodynamic polarization tests. The SECM area scan measurements showed more metastable pitting corrosion events for 30 min and 10 h aged specimens compared to the 48 h aged specimen at passive potential in 0.1M neutral chloride ion solution.

Correlation between AC magnetic susceptibility and pitting behaviour of sigma-phase containing duplex stainless steel

2015 ◽  
Vol 62 (6) ◽  
pp. 371-378 ◽  
Author(s):  
Kin Ho Lo ◽  
Chi Tat Kwok ◽  
Hong Cheng Kuan ◽  
Weng Kin Chan ◽  
Wenji Ai
Keyword(s):  
Stainless Steel ◽  
Magnetic Susceptibility ◽  
Duplex Stainless Steel ◽  
Sigma Phase ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
Ac Magnetic Susceptibility ◽  
Pitting Potential ◽  
Content Type ◽  
Passive Current

Purpose – The purpose of this paper is to characterize the pitting behaviour of sigma-phase-containing duplex stainless steel and investigate the correlation between magnetic susceptibility and pitting potentials. Design/methodology/approach – Use an alternating current (AC) magnetic susceptometer to trace the change in magnetic susceptibility associated with sigma phase formation and systematic study of the effects of sigma precipitation on pitting parameters as obtained using the anodic potentiodynamic polarization test. Findings – The precipitation of sigma phase impairs the general and pitting corrosion resistance of duplex stainless steel. The pitting potential, the corrosion potential and the AC magnetic susceptibility have good correlations. Unlike the pitting potential and the corrosion potential, the passive current and the corrosion current do not seem to possess any trend with annealing time. Originality/value – The correlation between AC magnetic susceptibility and pitting parameters has not been reported in the literature before.

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