Effect of Solution Annealing Time on the Microstructure and Corrosion Resistance of Duplex Stainless Steel

Abstract

The formation of intermetallic phases during thermal treatments is a decisive point for the performance of duplex stainless steels, which may prevent the obtaining or provoke degradation of their properties. This paper presents an investigation on the corrosion resistance of duplex SAF 2205 steel as received and after solution annealing treatment. The objective was to evaluate the correlation between the solution annealing time, the resulting microstructural changes and the corrosion resistance of the steel through electrochemical tests of cyclic potentiodynamic polarization and double-cycle potentiokinetic reactivation (DL-EPR). The heat treatments were performed at 1100° C for 30, 120 and 240 min with subsequent air cooling. The results of the DL-EPR showed that although there was no presence of intermetallic phases even with the absence of intermetallic phases, the solution annealing time influenced the degree of chromium depletion of the samples, so that with the increase of time, there was an increase in the degree of chrome depletion.

Temperature and time effect of thermal aging treatment on microstructure and corrosion resistance of UNS S31803 duplex stainless steel

“…Thus, DSS becomes more susceptible to the localized corrosion, for being sensitive to active dissolution and contributing to the degradation of passive film stability (Hilders et al, 2018, Jinlong et al, 2015, Lacerda et al, 2015, Li, Lo, Kwok, Sun & Lai, 2018, Mandal, 2016, Mohammed, Shrikrishna & Sathiya, 2016, Verma & Taiwade, 2017. Furthermore, the formation of α' causes a cross-stich displacement, leading to a decreased mobility of disagreements, leading to an increase in hardiness, in the yield point and mechanical resistance, besides reducing toughness and elongation (Appleton, 2019, Llorca-Isern, López-Jiménez, López-Luque, Biezma & Roca, 2016, Mandal, 2016, Marques, Silva & Santos, 2020, Mohammed et al, 2016, Paulraj & Garg, 2015, Rezende et al 2018, Rezende, Dainezi, Apolinario, Sousa & Mariano, 2019, Rivolta, Gerosa & Tavasci, 2018, Verma & Taiwade, 2017.…”

“…Phase α' can be formed by two mechanisms, nucleation and growth, and spinodal decomposition of ferrite, depending (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v10i8.17369 on the chemical composition of the ferrite phase and the temperature of the treatment. Both mechanisms occur to reduce the Gibbs free energy of the system and, consequently, promote a thermodynamically more stable state (Appleton, 2019, Llorca-Isern et al, 2016, Marques et al, 2020, Mohammed et al, 2016, Paulraj & Garg, 2015, Rezende et al 2018, Rivolta et al, 2018, Verma & Taiwade, 2017.…”

Influence of Homogenization and Annealing Temperatures on the Microstructure, Mechanical Properties, and Passive Properties of Cold Rolled 2205 Duplex Stainless Steel

“…A higher volume fraction of austenite than ferrite is observed for the FP1 sample, the fact seemed to be associated with the reversion mechanism from deformation-induced α'-martensite to austenite. Microstructural changes inside the austenitic lamellae are related to austenite-ferrite transformation 16 . Recrystallization of the ferrite progressed during annealing at 1000 °C so that the ferrite lamellae became larger.…”

“…On the other hand, the instability of the ferrite phase, due to improper heat treatment temperature, may cause the precipitation of deleterious secondary phases, such as the sigma phase in duplex stainless steels, which causes the Cr and Mo elements to be depleted in the regions adjacent to the matrix due to their consumption in solid solution, reducing the corrosion resistance and mechanical properties [14][15][16] .…”

Effect of Heat Treatment Atmospheres on Microstructure Evolution and corrosion resistance of 2205 Duplex Stainless Steel weldments

“…Improper annealing temperature promotes formation of intermetallic precipitation which depends on presence of Cr, Mo. Furthermore, several studies showed the Nearby zone of the Sigma phase depleted of Mo, Cr, whereas sigma phase enriched with Cr, Mo, and presence of intermetallic phases make duplex stainless steel was prone to Embrittlement [4], and consequently low corrosion resistance and deteriorated mechanical properties [9], [10] [11], [12] [13].…”