Establishing a New Solution Based on Hydrochloric Acid/Sodium Thiosulfate for Detecting and Measuring Degree of Sensitization of Stainless Steels Using Double-Loop Electrochemical Potentiodynamic Reactivation Method

CORROSION ◽  
2012 ◽  
Vol 68 (1) ◽  
pp. 015007-1-015007-11 ◽  
Author(s):  
M. Momeni ◽  
A. Ale-yassin ◽  
M.H. Moayed
CORROSION ◽  
10.5006/3559 ◽  
2020 ◽  
Vol 76 (8) ◽  
pp. 742-749
Author(s):  
Raul B. Rebak ◽  
Sheldon W. Dean

The sensitization of stainless steels may decrease their corrosion resistance in industrial applications. Traditional immersion tests exist to determine the degree of sensitization (DOS) of the stainless steels. However, electrochemical methods may be preferred because they are less expensive and faster to perform. The fast and robust double loop electrochemical potentiokinetic reactivation (DL-EPR) test has been introduced to the corrosion community some decades ago but an interlaboratory testing study was necessary to assess the repeatability and reproducibility of the DOS results. This work reports on a recent study where 11 laboratories returned results that show a high degree of confidence in the data obtained by DL-EPR.


2021 ◽  
Vol 21 (7) ◽  
pp. 3984-3988
Author(s):  
Kwang-Hu Jung ◽  
Seong-Jong Kim

The sensitization and passivation characteristics of AL-6XN heat-treated for up to 24 h at 800 °C were evaluated through double loop electrochemical potentiodynamic reactivation (2 M H2SO4 + 0.01 M KSCN +2 M NaCl solution) and cyclic potentiodynamic polarization (3.5% NaCl solution) test methods. Furthermore, the dependence between the characteristic values (Epit, Erep, and degree of sensitization) was discussed. The σ phase was precipitated at the intergranular and intragranular in AL-6XN at 800 °C. When the heat treatment time exceeded 1 hour, AL-6XN occurred rapid sensitization due to the precipitation of σ phase. In a 3.5% NaCl solution, the passivation characteristics of AL-6XN with sensitivity were very poor and depended much on the degree of sensitization.


2016 ◽  
Vol 850 ◽  
pp. 78-85 ◽  
Author(s):  
Bing Yi Liu ◽  
Ya Jun Xue ◽  
Zong Hui Yang ◽  
Xin Xian Fang

The corrosion behaviors of austenitic stainless steels, 304 and 316L as a contrast material, are investigated in hydrochloric acid corrosion under different conditions including immersion corrosion, single-phase flow and two-phase flow, respectively. The corrosion mass loss test and electrochemical test were carried out to evaluate the influence of medium temperature and concentration. The specimen surface morphologies and chemical compositions were obtained using scanning electron microscope to analyze the corrosion mechanism. The results show that the static corrosion rates of 304 and 316L steels and erosion corrosion rates of 304 steel increase obviously with the medium temperature increasing, but, the effect of hydrochloric acid concentration on their corrosion rate is less than that of the temperature. The corrosion current density values of 304 stainless steel increase and its passivation region of the polarization curve becomes narrowing and disappeared as the medium temperature increase. Uniform corrosion is the main way found on the surfaces of the stainless steels at room temperature in the hydrochloric acid solution. However, the selective corrosion occurs on their surface with the medium temperature increasing, and the higher temperature and concentration of corrosion medium, the more serious selective corrosion.


1997 ◽  
Vol 229 (1-2) ◽  
pp. 123-128 ◽  
Author(s):  
Nathalie Lopez ◽  
Mariano Cid ◽  
Monique Puiggali ◽  
Inaki Azkarate ◽  
Alberto Pelayo

2019 ◽  
Vol 43 (6) ◽  
pp. 369-375
Author(s):  
Muhammad Shahmy Hadi ◽  
Safaa N. Saud ◽  
Esah Hamzah ◽  
Mohd Fauzi Mamat

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Mehmet Emin Arıkan ◽  
Rafet Arıkan ◽  
Mustafa Doruk

In the present study as in our previous studies (Arikan and Doruk, 2008 and Arikan et al., 2012), similar specimens taken from a hot rolled cylindrical duplex stainless steel (DSS) bar with 22% Cr grade were solution annealed at 1050°C and then aged at 800∘C from 100 to 31622 min for sensitization treatment. Double loop electrochemical potentiodynamic reactivation and standard weight loss immersion acid tests were conducted. The solution annealed samples were found unsensitized. The samples aged for 100 min were less sensitized whereas samples aged for 316 min and more time were sensitized. The degree of sensitization (DOS) can be attributed to higher contribution of chromium and molybdenum depleted areas that result from intermetallic phases. However, especially the samples aged from 3162 to 31622 min have revealed chromium replenishment. Consequently, the degree of sensitization was lowered in comparison to the results obtained in previous studies.


2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Mehmet Emin Arıkan ◽  
Rafet Arıkan ◽  
Mustafa Doruk

Specimens taken from a hot-rolled cylindrical duplex stainless steel (DSS) bar with 22% Cr grade were solution annealed at1050∘C and then aged at725∘C from 100 to 31622 min for sensitization treatment. Double loop electrochemical potentiodynamic reactivation and standard weight loss immersion acid tests were conducted. The solution-annealed samples were found unsensitized. Those samples aged for 100 and 316 min were less sensitized whereas samples aged for 1000 min and especially those aged for 3162, 10000, and 31622 min were heavily sensitized. The degree of sensitization (DOS) can be attributed to higher contribution of chromium- and molybdenum-depleted areas resulting from intermetallic phases.


2011 ◽  
Vol 65 (2) ◽  
pp. 179-186 ◽  
Author(s):  
Bore Jegdic ◽  
Ana Alil ◽  
Zlatan Milutinovic ◽  
Zoran Odanovic ◽  
Bojan Gligorijevic ◽  
...  

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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