Investigation on ultra-pure ferritic stainless steel 436L susceptibility to intergranular corrosion using optimised double loop electrochemical potentiokinetic reactivation method

Intergranular corrosion (IGC) of Nb-Ti stabilized ferritic stainless steel (FSS) 429 was investigated using the double loop electrochemical potentiokinetic reactivation (DL-EPR) test combined with the microstructure observation. The results indicated that the optimized DL-EPR test condition for FSS 429 was the solution of 0.5 M H2SO4+ 0.0001 M KSCN with a scanning rate of 100 mV/min at 30°C. Based on this condition, the specimens aging at 400–700°C for different duration were tested and a time-temperature-sensitization (TTS) curve for FSS 429 was obtained, which reveals the sensitization nose was located around 550°C. The criticalIr/Iavalue was determined to be about 3% above which IGC occurred. After aging treatment, Cr depletion zone was detected using energy dispersive spectroscopy (EDS), most possibly due to Cr segregation around intergranular TiC and NbC.

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Determination of Intergranular Corrosion Susceptibility of Z3CN20.09M Cast Duplex Stainless Steel by a Modified Double Loop Electrochemical Potentiokinetic Reactivation Method

Energy Materials 2014 ◽

10.1007/978-3-319-48765-6_68 ◽

2014 ◽

pp. 557-562

Author(s):

Y. Z. Shi ◽

B. Yang ◽

M. X. Zhang ◽

H. C. Wu ◽

S. L. Wang

Keyword(s):

Stainless Steel ◽

Duplex Stainless Steel ◽

Intergranular Corrosion ◽

Double Loop ◽

Electrochemical Potentiokinetic Reactivation ◽

Corrosion Susceptibility

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Evaluation of the Susceptibility to Intergranular Corrosion for a Novel Cr-Mn-N Austenitic Stainless Steel Using DL-EPR

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.631-632.192 ◽

2013 ◽

Vol 631-632 ◽

pp. 192-197

Author(s):

Lei Gang Zheng ◽

Xiao Qiang Hu ◽

Xiu Hong Kang ◽

Dian Zhong Li

Keyword(s):

Stainless Steel ◽

Austenitic Stainless Steel ◽

Electrolyte Solution ◽

Intergranular Corrosion ◽

Xrd Analysis ◽

Double Loop ◽

Chromium Depletion ◽

Electrochemical Potentiokinetic Reactivation ◽

Epr Test ◽

Optical Micrographs

The sensitization and intergranular corrosion (IGC) behavior of a novel Cr-Mn-N austenitic stainless steel (named as MPMD133) sensitized in the temperature range from 600 oC to 1000oC for 3 hours was investigated by the double loop electrochemical potentiokinetic reactivation (DL-EPR) test. The effects of the sensitization temperature on the susceptibility to IGC of MPMD133 were examined in the 0.5M H2SO4 +0.01M KSCN electrolyte solution. The results show that the degree of IGC increases as the sensitization temperature increasing till 900oC. Meanwhile it decreases rapidly when the sensitization temperature is elevated up to 1000oC, which is confirmed by the subsequent optical micrographs observation. The XRD analysis reveals that the precipitation of Cr23C6 leads to chromium depletion along the grain boundaries, consequently results in the susceptibility to IGC.

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Application of electrochemical methods for the investigation of intergranular corrosion welded joint austenitic stainless steel 19Cr-9Ni

Hemijska industrija ◽

10.2298/hemind101122005j ◽

2011 ◽

Vol 65 (2) ◽

pp. 179-186 ◽

Cited By ~ 1

Author(s):

Bore Jegdic ◽

Ana Alil ◽

Zlatan Milutinovic ◽

Zoran Odanovic ◽

Bojan Gligorijevic ◽

...

Keyword(s):

Stainless Steel ◽

Austenitic Stainless Steel ◽

Welded Joints ◽

Intergranular Corrosion ◽

Significant Degree ◽

Electrochemical Methods ◽

Double Loop ◽

Quantitative Evidence ◽

Degree Of Sensitization ◽

Electrochemical Potentiokinetic Reactivation

Sensitization degree of the austenitic stainless steel welded joints was investigated by electrochemical methods of the double loop electrochemical potentiokinetic reactivation (DL EPR) in H2SO4 + KSCN solution, and by the measurement of corrosion potential of the steel in the drop of the solution of HNO3 + FeCl3 + HCl. The welded joints were tested by X-ray radiographic method in order to check the presence of the weld defects. Grain size of the base metal and the welded joints were determined by optical microscopy. Good agreement between the results obtained by different electrochemical methods was obtained. Heat-affected zone (HAZ) of the austenitic stainless steel welded joints has shown significant degree of sensitization. The double loop electrochemical potentiokinetic method gave quantitative evidence about susceptibility of the stainless steel to intergranular corrosion.

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