Pitting behavior of friction stir repair-welded 304L stainless steel in 3.5% NaCl solution at room temperature: role of grain and defect structures

Naskar, Anirban; Bhattacharyya, Madhumanti; Raja, Krishnan S.; Charit, Indrajit; Darsell, Jens T.; Jana, Saumyadeep

doi:10.1007/s42452-020-03935-0

Cited by 10 publications

(5 citation statements)

References 56 publications

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“…Furthermore, the combination of the decreasing θ max with the low-frequency range indicates that the cracking process is being developed [59]. At the "Failure", the θ max decreased to -60 • , and the attenuation of the peak found at high frequencies denotes a deep crack [60].…”

Section: Electrochemical Impedance Spectroscopy (Eis)mentioning

confidence: 99%

Stress Corrosion Cracking Mechanisms of UNS S32205 Duplex Stainless Steel in Carbonated Solution Induced by Chlorides

Martin

Bastidas

2023

Metals

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Herein, the chloride-induced stress corrosion cracking (SCC) mechanisms of UNS S32205 duplex stainless steel (DSS) reinforcing bars in alkaline and carbonated solutions are studied. Electrochemical monitoring and mechanical properties were tested using linear polarization resistance and electrochemical impedance spectroscopy, coupled with the slow strain rate tensile test (SSRT) to evaluate the SCC behavior and unravel the pit-to-crack mechanisms. Pit initiation and crack morphology were identified by fractographic analysis, which revealed the transgranular (TG) SCC mechanism. HCO3− acidification enhanced the anodic dissolution kinetics, thus promoting a premature pit-to-crack transition, seen by the decrease in the maximum phase angle in the Bode plot at low frequencies (≈ 1 Hz) for the carbonated solution. The crack propagation rate for the carbonated solution increased by over 100% compared to the alkaline solution, coinciding with the lower phase angle from the Bode plots, as well as with the lower charge transfer resistance. Pit initiation was found at the TiN nonmetallic inclusion inside the ferrite phase cleavage facet, which developed TG-SCC.

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Section: Electrochemical Impedance Spectroscopy (Eis)mentioning

confidence: 99%

Stress Corrosion Cracking Mechanisms of UNS S32205 Duplex Stainless Steel in Carbonated Solution Induced by Chlorides

Martin

Bastidas

2023

Metals

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“…Friction stir welding or processing (FSW or FSP) is another surface modification process that leads to grain refinement, low-angle grain boundaries, and compressive residual stress distribution on the stirred zone (SZ) [26]. The friction-stirred 304L material showed better resistance to pitting corrosion in the acidified chloride solution than the base metal (BM) in mill-annealed conditions [27,28]. Therefore, FSW and FSP can be beneficial in preventing SCC damage in austenitic SS structures.…”

Section: Introductionmentioning

confidence: 99%

“…Our previous studies showed that friction stir welding of 304L resulted in excessive grain refinement due to heavy plastic deformation and a higher fraction of low-angle grain boundaries due to dislocation rearrangement [27,28]. The low-angle grain boundaries could supply more misorientation dislocations at the metal/film interface, forming anion vacancies by a dislocation-climb process.…”

Section: Introductionmentioning

confidence: 99%

Chloride-Induced Stress Corrosion Cracking of Friction Stir-Welded 304L Stainless Steel: Effect of Microstructure and Temperature

Naskar,

Bhattacharyya,

Jana

et al. 2024

Crystals

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Dry storage canisters of used nuclear fuels are fabricated using SUS 304L stainless steel. Chloride-induced stress corrosion cracking (CISCC) is one of the major failure modes of dry storage canisters. The cracked canisters can be repaired by friction stir welding (FSW), a low-heat input ‘solid-phase’ welding process. It is important to evaluate the ClSCC resistance of the friction stir welded material. Stress corrosion cracking (SCC) studies were carried out on mill-annealed base materials and friction stir welded 304L stainless U-bend specimens in 3.5% NaCl + 5 N H2SO4 solution at room temperature and boiling MgCl2 solution at 155 °C. The engineering stress on the outer fiber of the FSW U-bend specimen was ~60% higher than that of the base metal (BM). In spite of the higher stress level of the FSW, both materials (FSW and BM) showed almost similar SCC failure times in the two different test solutions. The SCC occurred in the thermo-mechanically affected zone (TMAZ) of the FSW specimens in the 3.5% NaCl + 5 N H2SO4 solution at room temperature, while the stirred zone (SZ) was relatively crack-free. The failure occurred at the stirred zone when tested in the boiling MgCl2 solution. Hydrogen reduction was the cathodic reaction in the boiling MgCl2 solution, which promoted hydrogen-assisted cracking of the heavily deformed stirred zone. The emergence of the slip step followed by passive film rupture and dissolution of the slip step could be the SCC events in the 3.5% NaCl + 5 N H2SO4 solution at room temperature. However, the slip step height was not sufficient to cause passivity breakdown in the fine-grained SZ. Therefore, the SCC occurred in the partially recrystallized softer TMAZ. Overall, the friction-stirred 304L showed higher tolerance to ClSCC than the 304L base metal.

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“…The cracks formed during aggressive service conditions are generally covered with an oxide layer that breaks down during the FSP and incorporated as a welding defect known as 'lazy-S'. The 'lazy-S' is a spiraled feature consisting of oxide or carbide particles residing on the surface of the crack being repaired and forms an interface between the advancing and retreating sides of the SZ [21,22]. Our recent work showed that the simulated crack repaired SZ of 304 SS showed lower corrosion resistance than that of the base metal (BM) [22].…”

Section: Introductionmentioning

confidence: 99%

“…The 'lazy-S' is a spiraled feature consisting of oxide or carbide particles residing on the surface of the crack being repaired and forms an interface between the advancing and retreating sides of the SZ [21,22]. Our recent work showed that the simulated crack repaired SZ of 304 SS showed lower corrosion resistance than that of the base metal (BM) [22]. The lower corrosion resistance of the FSPed specimens was attributed to the presence of 'lazy-S' which acted as a preferential pit initiation site.…”

Section: Introductionmentioning

confidence: 99%

Room temperature corrosion behaviour of plastically deformed AISI 304 stainless steel by friction stir welding in neutral and acidified chloride solutions

Naskar

Bhattacharyya

Raja

et al. 2022

Corrosion Engineering, Science and Technology

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Severe plastic deformation of 304L stainless steel plate was carried out by friction stirring under an isothermal tool temperature at 825°C. The friction stirred zone showed extensive grain refinement, high fraction of low angle grain boundaries due to dislocation rearrangement, Σ3 and Σ9 special grain boundaries and discrete Fe-Cr-Mn-rich particles. Electrochemical polarisation measurements were done on the base metal (BM) and friction stir welded (FSW) specimens in the neutral and acidified 3.5% NaCl solutions. The BM showed marginally better pitting resistance in the neutral chloride solution than the FSW because of a larger fraction of special grain boundaries, and larger grain size. Whereas in acidified 3.5% NaCl solution, the FSW showed better corrosion resistance than the BM. The surface film of the FSW had a lower impedance and a lower defect concentration than the BM indicating higher diffusivity of point defects in the FSW.

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Pitting behavior of friction stir repair-welded 304L stainless steel in 3.5% NaCl solution at room temperature: role of grain and defect structures

Cited by 10 publications

References 56 publications

Stress Corrosion Cracking Mechanisms of UNS S32205 Duplex Stainless Steel in Carbonated Solution Induced by Chlorides

Stress Corrosion Cracking Mechanisms of UNS S32205 Duplex Stainless Steel in Carbonated Solution Induced by Chlorides

Chloride-Induced Stress Corrosion Cracking of Friction Stir-Welded 304L Stainless Steel: Effect of Microstructure and Temperature

Room temperature corrosion behaviour of plastically deformed AISI 304 stainless steel by friction stir welding in neutral and acidified chloride solutions

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