Critical Pitting Temperature of a 22-05 Duplex Stainless Steel and Pitting Potential Statistics

2019 ◽  
Vol 16 (52) ◽  
pp. 297-305 ◽  
Author(s):  
Capucine Dussart ◽  
Lionel Peguet ◽  
Alain Gaugain ◽  
Bernard Baroux
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Pitting Potential ◽  
Critical Pitting Temperature

scholarly journals The Microstructure and Pitting Resistance of 2002 Lean Duplex Stainless Steel after the Simulated Welding Thermal Cycle Process

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 70 ◽  
Author(s):  
Yuanyuan Yang ◽  
Yanjun Guo ◽  
Yuanyuan Liu ◽  
Jin Li ◽  
Yiming Jiang
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Heat Input ◽  
Strong Dependence ◽  
Austenite Phase ◽  
Cooling Rates ◽  
Pitting Potential ◽  
Lean Duplex Stainless Steel ◽  
Welding Thermal Cycle ◽  
Critical Pitting Temperature

In this paper, thermal cycles with different heat inputs and cooling rates were investigated for a novel lean duplex stainless steel 2002 using a welding simulation. The microstructure and pitting resistance of the simulated heat-affected zones were studied. With the increasing heat input, the amount and size of the austenite phase both increased, along with a transformation from rods to dendritic structures. The critical pitting temperature (CPT) and the pitting potential (Epit) both increased first and then declined as the heat input increased, indicating a strong dependence of pitting resistance on the heat input. For the different cooling rates, the amount of ferrite increased as the cooling rate increased from 0.25 °C/s to 20 °C/s. The CPT and Epit both increased with the increasing cooling rates, indicating an improved pitting resistance. The pits initiated preferentially at the boundaries of ferrite and austenite due to the precipitation of M23C6 in the specimens with different cooling rates.

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.

Effects of the α/γ-Phase Ratio on the Corrosion Behavior of Cast Duplex Stainless Steel

CORROSION ◽  
10.5006/3464 ◽  
2020 ◽  
Vol 76 (9) ◽  
pp. 815-825
Author(s):  
Ryotaro Yamamoto ◽  
Hiroshi Yakuwa ◽  
Matsuho Miyasaka ◽  
Nobuyoshi Hara
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Chloride Ions ◽  
Phase Ratio ◽  
Potential Range ◽  
High Concentration ◽  
Active Dissolution ◽  
Pitting Potential ◽  
Potential Measurement ◽  
Α Phase

The effects of the α/γ-phase ratio on pitting corrosion initiation and growth in cast duplex stainless steel were studied, including the preferential dissolution of the two phases inside the pits, using pitting potential measurement and potentiostatic polarization measurement with a high concentration of chloride ions and a low pH. The initiation of pitting was not dependent on the α-phase ratio. The γ phase preferentially dissolves when a high potential in the active dissolution region is applied, and the α phase preferentially dissolves when a low potential is applied. In addition, with an increase in α-phase ratio, the potential range where the α phase preferentially dissolves enlarged toward the higher potential side. The growth rate of stable pitting increased with the α-phase ratio. Dissolution of the α phase increased with an increase in the α-phase ratio. This phenomenon is presumably caused by the decreased amount of Cr in the α phase, resulting from the increased α-phase ratio, as well as by Cr depletion around Cr nitrides.

Effect of temperature change rate on the critical pitting temperature for duplex stainless steel

2009 ◽  
Vol 39 (10) ◽  
pp. 1703-1708 ◽  
Author(s):  
Lihua Zhang ◽  
Yiming Jiang ◽  
Bo Deng ◽  
Daoming Sun ◽  
Juan Gao ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Temperature Change ◽  
Effect Of Temperature ◽  
Change Rate ◽  
Temperature Change Rate ◽  
Critical Pitting Temperature
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