Intergranular corrosion of welded joints of austenitic stainless steels studied by using an electrochemical minicell

Garcı́a, C.; Tiedra, Pilar De; Blanco, Y.; Martín, Óscar; Martín, Fernando

doi:10.1016/j.corsci.2008.06.016

Cited by 132 publications

(56 citation statements)

References 30 publications

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“…39 Delta ferrite can be found along cell boundaries in welds if the austenitic SS solidifies first as primary austenite, as in these cellular regions. 39,46 In general, the amount of delta ferrite retained is inversely proportional to the cooling rate. As cooling rates of the SLM materials can be extremely high, little delta ferrite is expected.…”

Section: Discussionmentioning

confidence: 99%

The Role of Microstructure and Surface Finish on the Corrosion of Selective Laser Melted 304L

Schaller

Mishra²,

Rodelas

et al. 2018

J. Electrochem. Soc.

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The corrosion behavior of selective laser melted (SLM) 304L was investigated and compared to conventional wrought 304L in aqueous chloride and acidic solutions. Through immersed electrochemical testing and exposure in acidic solutions, the SLM 304L exhibited superior pitting resistance in the polished state compared to wrought 304L. However, the surface condition of the SLM material had a great impact on its corrosion resistance, with the grit-blasted condition exhibiting severely diminished pitting resistance. Local scale, capillary micro-electrochemical and scanning electrochemical microscopy investigations, identified porosity as a contributing factor to decreased corrosion resistance. Preferential corrosion attack was not observed to be related to the characteristic underlying cellular microstructure produced through SLM processing. This study highlights the effects of SLM microstructural features on corrosion resistance, specifically the substantial influence of surface finish on SLM corrosion behavior and the need for development and optimization of processing techniques to improve surface finish. Powder bed selective laser melting (SLM) has become a desirable and widely used technique for the additive manufacturing (AM) of metal parts. While a significant amount of research has been carried out on the mechanical properties of SLM materials, little is known regarding their corrosion behavior. Of the few corrosion studies that do exist, the primary focus has been on evaluating general corrosion resistance.1,2 A few recent investigations have examined the role of processing and microstructure on the material corrosion behavior in more detail.3,4 However, there is still a need for further investigation in order to develop a full understanding of the microstructural and morphological characteristics inherent to AM materials due to the unique processing conditions and their relative contributions to the materials' corrosion behavior. Ideally, a ranking of the deleterious or advantageous properties formed in AM materials with respect to corrosion should be established. This is necessary for a variety of alloy systems in engineering relevant solutions and environments to help inform and guide future processing parameters, build designs, and materials selection.The powder bed process along with extremely high cooling rates and temperature gradients during SLM processing create microstructures and part surfaces that differ greatly from their conventional thermo-mechanically processed counterparts. Several characteristics are expected or have known effects on corrosion behavior including surface finish, porosity, inclusions (MnS, oxides, etc.), and microstructures formed through non-equilibrium cooling conditions. For example, a strong relationship between surface roughness and corrosion susceptibility has been observed in which pit initiation decreases with decreasing surface roughness in chloride solutions.5-7 Porosity, formed by entrapped gas or lack of fusion of powder particles in the SLM build, can also reduce...

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Section: Discussionmentioning

confidence: 99%

The Role of Microstructure and Surface Finish on the Corrosion of Selective Laser Melted 304L

Schaller

Mishra²,

Rodelas

et al. 2018

J. Electrochem. Soc.

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“…DL EPR metodu je razradio V. Čihal [6,12] i našla je primenu za ispitivanje sklonosti prema interkristalnoj koroziji ne samo austenitnih čelika [13], već i feritnih [7], duplex nerđajućih čelika [14], itd. DL EPR metoda se primenjuje za ispitivanje sklonosti zavarenih spojeva nerđajućih čelika prema interkristalnoj koroziji, kao i za ispitivanje sklonosti prema naponskoj koroziji [11].…”

Section: Slika 1 Primer Ispitivanja Sklonosti Prema Interkristalnoj unclassified

Influence of welding current intensity on susceptibility to intergranular corrosion in welded joints of stainless steel

Jegdic¹,

Bobic²,

Alić³

2017

Zavarivanje i zavarene konstrukcije

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IzvodIspitana je sklonost prema interkristalnoj koroziji zavarenog spoja austenitnog nerđajućeg čelika X5Cr-Ni18-10. Zavareni spoj je formiran pri različitim jačinama struje zavarivanja (110 A, 130 A i 150 A). Ispitivanja su vršena metodom elektrohemijske potenciokinetičke reaktivacije sa dvostrukom petljom (DL EPR metoda), na osnovnom metalu i u zoni uticaja toplote (ZUT). Osnovni metal je otporan prema interkristalnoj koroziji. Zona uticaja toplote formirana pri zavarivanju strujom jačine 150 A pokazuje najveću sklonost prema interkristalnoj koroziji. Sklonost prema interkristalnoj koroziji je znatno niža pri zavarivanju manjim jačinama struje. Pokazatelj sklonosti prema interkristalnoj koroziji (Q r /Q p ) GBA je ~ 6 puta veći za zonu uticaja toplote (pri jačini struje zavarivanja od 150 A) nego za osnovni metal. Na osnovu prikazanih rezultata može se zaključiti da jačina struje zavarivanja u velikoj meri utiče na sklonost zavarenog spoja nerđajućeg čelika X5CrNi18-10 prema interkristalnoj koroziji. AbstractSusceptibility to intergranular corrosion in welded joints of austenitic stainless steel X5Cr-Ni18-10 was tested. The welding was performed with different intensity of welding current (110 A, 130 A and 150 A). The tests were performed using electrochemical potentiokinetic reactivation method with double loop (DL EPR method) on the base metal and in the heat affected zone. The results obtained by the DL EPR method show that the heat affected zone formed by welding with 150 A has the highest susceptibility to intergranular corrosion. The susceptibility to intergranular corrosion is considerably lower when applying smaller welding current. The base metal is resistant to intergranular corrosion. The indicator of susceptibility to intergranular corrosion (Qr/Qp) GBA is ~ 6 times higher for the heat affected zone (at 150 A welding current intensity) than for the base metal. Obtained testing results show that the welding current intensity greatly influences the susceptibility to intergranular corrosion in welded joints of stainless steel X5Cr-Ni18-10. UVOD Interkristalna korozija je vid lokalne korozije koji se manifestuje rastvaranjem oblasti granica zrna. Pri laganom hlađenju ili zagrevanju austenitnih nerđajućih čelika, u temperaturnom intervalu od 420 o C do 820 o C, po granicama zrna se izdvajaju karbidi bogati hromom, prvenstveno M 23 C 6 [1][2][3]. Izdvajanje karbida hroma izaziva osiromašenje prigraničnih oblasti zrna hromom. To je posledica spore difuzije hroma u austenitu u navedenom temperaturnom intervalu. Ako je sadržaj hroma manji od sadržaja koji je neophodan za održavanje zaštitnog pasivnog filma, oblast neposredno uz granicu zrna postaje senzibilizovana i podložna interkristalnoj koroziji. Prigranične zone, siromašne hromom, imaju veću brzinu rastvaranja u odnosu na ostale oblasti zrna [1]. Senzibilizacija nerđajućeg čelika prema interkristalnoj koroziji se najčešće javlja u

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“…Higher magnifications in the observation of corrosion processes is a very important point because despite the fact that the effects of corrosion processes are visible at large scale, its mechanisms happen at a smaller scale. Some authors have used microscopic systems such as microcells, scanning electrochemical microscopy or atomic force microscopy in order to study in-situ corrosion processes (García et al, 2008a;García et al, 2008b;Martin et al, 2008). These experimental devices can be applied to different settings, such as heterogeneous materials (dual phase steels, welding, etc).…”

Section: Previous Corrosion Studies With Image Acquisition Systemsmentioning

confidence: 99%

Application of Confocal Laser Scanning Microscopy to the In-situ and Ex-situ Study of Corrosion Processes

Leiva-García¹,

Garcı́a-Antón²,

Muñoz-Portero³

2011

Laser Scanning, Theory and Applications

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Intergranular corrosion of welded joints of austenitic stainless steels studied by using an electrochemical minicell

Cited by 132 publications

References 30 publications

The Role of Microstructure and Surface Finish on the Corrosion of Selective Laser Melted 304L

The Role of Microstructure and Surface Finish on the Corrosion of Selective Laser Melted 304L

Influence of welding current intensity on susceptibility to intergranular corrosion in welded joints of stainless steel

Application of Confocal Laser Scanning Microscopy to the In-situ and Ex-situ Study of Corrosion Processes

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