Influence of the Heterogeneous Nucleation Sites on the Kinetics of Intermetallic Phase Formation in Aged Duplex Stainless Steel

Melo, Elis Almeida; Magnabosco, Rodrigo

doi:10.1007/s11661-017-4299-z

Cited by 18 publications

(9 citation statements)

References 17 publications

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“…Most of this secondary phase is distributed in the rolling direction of the sample, involving the ferrite phase. It is also possible the precipitation of both sigma and chi phases simultaneously at a particular temperature and some residual chi phase can also be detected while the sigma phase progresses in its precipitation [3,5,22,[30][31][32][33][34][35][36]; this is why both phases are observed in Figure 5a.…”

Section: Microstructural Evolution After Carburizing Process and Shormentioning

confidence: 99%

Study of the Thermochemical Surface Treatment Effect on the Phase Precipitation and Degradation Behaviour of DSS and SDSS

2020

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In this study, the effect of a plasma ion carburizing process to duplex and superduplex stainless steels (DSS and SDSS), at 925 °C for a long time, as thermochemical process influencing the microstructural evolution is presented. The objective is to analyse the diffusion elements’ influence on the precipitation of secondary phases after additional short thermal treatment. A comparison among the different treatments was performed after the resulting microstructures were analysed by Field Emission—Scanning Electron Microscope. Precipitation of secondary phases—sigma (σ), chi (χ), nitrides and carbides—seemed to occur during the treatments in a similar way for both steels (DSS and SDSS), although they showed a different morphology and precipitation mode. General corrosion behaviour of untreated and treated samples was investigated by potentiodynamic tests in order to prove their corrosion resistance. It was found that an improvement of the surface protection after the plasma carburizing process occurred.

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Section: Microstructural Evolution After Carburizing Process and Shormentioning

confidence: 99%

Study of the Thermochemical Surface Treatment Effect on the Phase Precipitation and Degradation Behaviour of DSS and SDSS

2020

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“…It has been verified that the critical formation time for σ or other phases depends on several factors such as the amount of Cr, Mo and N, the solution treatment temperature and for the most part on the cooling rate during quenching: higher the cooling rate, lower the amount of precipitated phases [12,13]. From previous works, the critical cooling rate for 2205 has been established at 0.35 °C/s and for 2507 has been estimated as being higher than approximately 0.8÷0.9 °C/s, when a final σ-phase content of about 0.2% was obtained [13,14].The precipitation kinetics of secondary phases becomes faster by finer ferrite and austenite grain size [8], due to the higher grain boundary surface, serving as preferential nucleation site [15].…”

Section: Introductionmentioning

confidence: 97%

“…Despite these technological aspects, a complete and definitive description of secondary phases formation in DSSs is still unavailable and several different precipitation sequences of various intermetallic phases have been proposed. Some authors [3,4,8,9] suggest that the precipitation of σ-phase is associated with intermediate precipitation of χ-phase, which subsequently transforms into σ-phase, while some other authors associate the phases formation to nitrides precipitation [10].Also, in lean duplex stainless steels the precipitation of σ was observed without any χ-phase precipitation [11].…”

Section: Introductionmentioning

confidence: 99%

Investigation on Solid State Phase Transformations in a 2510 Duplex Stainless Steel Grade

Calliari¹,

Breda²,

Gennari³

et al. 2020

Preprint

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Duplex and Super Duplex Stainless Steels are very prone to secondary phases formation related to ferrite decomposition at high temperatures. In the present paper the results on secondary phase precipitation in a 2510 Duplex Stainless Steel, heat treated in the temperature range 850-1050 °C for 3-30 minutes are presented. The precipitation starts at grain boundaries with a consistent ferrite transformation for very short times. The noses of the TTP curves are at 1000 °C for σ-phase and at 900 °C for χ-phase, respectively. The precipitation sequence involves a partial transformation of χ into σ, as previously evidenced in 2205 and 2507 grades. Furthermore, the experimental data were compared to the results of Thermo-Calc calculations.

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“…Despite these technological aspects, a complete and definitive description of secondary phases formation in DSSs is still unavailable and several different precipitation sequences of various intermetallic phases have been proposed. Some authors [3,4,8,9] suggest that the precipitation of σ-phase is associated with intermediate precipitation of χ-phase, which subsequently transforms into σ-phase, while some other authors associate the phase formations to nitride precipitation [10]. Additionally, in lean duplex stainless steels, the precipitation of σ was observed without any χ-phase precipitation [11].…”

Section: Introductionmentioning

confidence: 99%

Investigation on Solid-State Phase Transformations in a 2510 Duplex Stainless Steel Grade

Calliari

Breda²,

Gennari

et al. 2020

Metals

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Duplex and Super Duplex Stainless Steels are very prone to secondary phases formation related to ferrite decomposition at high temperatures. In the present paper the results on secondary phase precipitation in a 2510 Duplex Stainless Steel, heat-treated in the temperature range 850–1050 °C for 3–30 min are presented. The precipitation starts at grain boundaries with a consistent ferrite transformation for very short times. The noses of the Time–Temperature–Precipitation (TTP) curves are at 1000 °C for σ-phase and at 900 °C for χ-phase, respectively. The precipitation sequence involves a partial transformation of χ into σ, as previously evidenced in 2205 and 2507 grades. Furthermore, the experimental data were compared to the results of Thermo-Calc calculations. Understanding and ability to predict phase stability in 2510 duplex stainless steel is a key factor to design optimal welding processes that avoid any secondary phase precipitation in the weld bead as well as in the heat-affected zone.

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Influence of the Heterogeneous Nucleation Sites on the Kinetics of Intermetallic Phase Formation in Aged Duplex Stainless Steel

Cited by 18 publications

References 17 publications

Study of the Thermochemical Surface Treatment Effect on the Phase Precipitation and Degradation Behaviour of DSS and SDSS

Study of the Thermochemical Surface Treatment Effect on the Phase Precipitation and Degradation Behaviour of DSS and SDSS

Investigation on Solid State Phase Transformations in a 2510 Duplex Stainless Steel Grade

Investigation on Solid-State Phase Transformations in a 2510 Duplex Stainless Steel Grade

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