Practical aspects on the use of on-site Double Loop Electrochemical Potentiodynamic Reactivation Technique (DL-EPR) for Duplex Stainless Steel

Assis, Kioshy Santos de; Rocha, Anne Caroline da Silva; Margarit-Mattos, I.C.P.; Serra, Flavio A. S.; Mattos, O.R.

doi:10.1016/j.corsci.2013.04.050

Cited by 31 publications

(18 citation statements)

References 19 publications

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“…[34][35][36] The meaning of high values for Ir/Ia and Qr/Qa were generally explained by the presence of deleterious phases. [34][35] However, these high ratios were obtained for alloys tested in the annealed condition and the high ratios were a result of preferential corrosion of the ferrite phase. It was emphasized that the use of DL-EPR in the field should be preceded by exhaustive work characterizing the duplex steel in the laboratory.…”

Section: Introductionmentioning

confidence: 97%

“…39,41 In previous papers, results exploring the effect of the microstructure of DSS in the kinetic parameters obtained by DL-EPR have been presented. [34][35][36] In the present work, the objective was to provide a critical view of the detection of deleterious phases in duplex steel and to compare the DL-EPR technique with the use of EC method.…”

Section: Introductionmentioning

confidence: 99%

“…However, the complexity of this class of stainless steel can be easily seen in the complete lack of consensus on the proper parameters for the operation of the DL-EPR tests, such as electrolyte composition and scan rate. [27][28][29][30][31][32][33][34][35][36][37] Improving the choice of experimental parameters by using optimizing methods has been proposed. 38 In our laboratory, we are not following this approach of finding the best experimental condition for each class of DSS.…”

Section: Introductionmentioning

confidence: 99%

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Magnetic and Electrochemical Techniques as Tools to Detect Deleterious Phases in Duplex Stainless Steels

Leal¹,

Assis²,

Mattos³

et al. 2015

Corrosion

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The development of techniques to detect deleterious phases in duplex and super duplex stainless steel has a great technicalscientific appeal. However, establishing a quality control of these steels using a unique technique of inspection requires an attentive analysis about its limits and sensibility of detections. Thus, the current work compares magnetic techniques based on eddy current methods and electrochemical potentiokinetic reactivation with double loop to detect deleterious phases in duplex stainless steel. The limitations and advantages of each technique are discussed mainly concerning the viability to detect sigma phase and chromium nitride. KEY WORDS: cyclic voltammetry, duplex stainless steel, sigma phase ISSN 0010-9312 (print), 1938-159X (online) 15/000141/$5.00+$0.50/0 © 2015, NACE International

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Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Magnetic and Electrochemical Techniques as Tools to Detect Deleterious Phases in Duplex Stainless Steels

Leal¹,

Assis²,

Mattos³

et al. 2015

Corrosion

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“…Besides those advantages, DSS are submitted to sensitization when exposed to a number of high temperatures between 300-900 ºC, with the formation of numerous deleterious phases, such as carbides (MC, M 6 C, M 7 C 3 , M 23 C 6 ), chromium nitrides (Cr 2 N), σ phase and χ phase. In smaller time ranges, σ phase precipitates on δ/γ e δ/δ interfaces, which affects the DSS properties, being the σ phase a very hard and brittle intermetallic compound [3,4]. Elevated levels of chromium and molybdenum may promote the σ phase formation, which occurs during processes that involve heat treatment, plastic deformation or yet due to aging [5].…”

Section: Introduction (Word Style (Times New Roman))mentioning

confidence: 99%

Intergranular Corrosion of UNS S31803 Heat Treated at 800 °C Varying Range Times

Dias¹,

Santos²,

Viana³

2015

JCCE

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Abstract:The aim of this work is evaluate the intergranular corrosion on UNS S31803 steel, with heat treatments at 800 °C, varying treatment times of 30 mins, 360 mins and 1,440 mins. The results confirm the formation of σ phases and secondary austenite (γ 2 ). For the analysis of the influence of σ and γ 2 phases, metallographic analysis were conducted through optical microscopy, potentiokinetic reactivation electrochemical techniques and potentiodynamic polarization in NaCl 3.5% solution. Microstructural analysis has shown a formation of γ 2 and σ phase in heat treatment, due to diffusion of chromium and molybdenum from δ phase to γ phase, precipitating on δ/γ and δ/δ interfaces. The DL-EPR (Double loop electrochemical potentiokinetic reactivation) results have shown an increase of the DOS (degree of sensitization) for long periods of time on heat treatment. The results of potentiodynamic polarization showed a reduction of the corrosion and pitting potentials, followed by an increase of the current density when the UNS S31830 steel is heat treated during long periods of time.

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“…Barreto et al 7 employed a solution with 2.00 M H 2 SO 4 + 0.01 M KSCN + 1.00 M NaCI and performed the DL-EPR test with scan rates between 1.5 and 3.0 mV/s in situ. They observed that the DOS was sensitive to deleterious phases in amounts above 8.00%.…”

Section: Introductionmentioning

confidence: 99%

Nondestructive Microstructural Characterization of Superduplex Stainless Steel by Double Loop Electrochemical Polarization Reactivation Portable Test

et al. 2017

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Superduplex stainless steels (SDSS) are frequently employed in the petrochemical industries where is required high mechanical strength, toughness, and corrosion resistance. However, these properties can be affected by deleterious phases formation due thermomechanical processes applied in the field during pipes and vessels construction. This work propose the nondestructive microstructural characterization of deleterious phases precipitated in SDSS isothermally treated in 800 and 850ºC using portable double loop electrochemical polarization reactivation tests (DL-EPR). The results obtained in this nondestructive test are quite close to those obtained by conventional test, and can be correlated with the amount of deleterious phases precipitated. It can be concluded that the microstructural degradation of superduplex stainless steel can be evaluated by portable DL-EPR test with slow sweep rates, using a special cell and a proper electrolyte at room temperature.

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Practical aspects on the use of on-site Double Loop Electrochemical Potentiodynamic Reactivation Technique (DL-EPR) for Duplex Stainless Steel

Cited by 31 publications

References 19 publications

Magnetic and Electrochemical Techniques as Tools to Detect Deleterious Phases in Duplex Stainless Steels

Magnetic and Electrochemical Techniques as Tools to Detect Deleterious Phases in Duplex Stainless Steels

Intergranular Corrosion of UNS S31803 Heat Treated at 800 °C Varying Range Times

Nondestructive Microstructural Characterization of Superduplex Stainless Steel by Double Loop Electrochemical Polarization Reactivation Portable Test

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