Study of Sigma Phase in Duplex SAF 2507

Fellicia, Dian Mughni; Sutarsis,; Kurniawan, Budi Agung; Wulanari, Dieski Nuntasi; Purniawan, Agung; Wibisono, Alvian Toto

doi:10.1088/1757-899x/202/1/012039

Cited by 15 publications

(6 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The block-shaped specimens were wire-cut to 80×17×17 mm 3 , heated to 1050 ℃, held for 60 min and then quickly quenched in water. Finally, the Ce-modified SAF 2507 SDSS specimens in solid solution state were obtained [27].…”

Section: Methodsmentioning

confidence: 99%

Controlled cold rolling effect on microstructure and mechanical properties of Ce-modified SAF 2507 super duplex stainless steel

Zhou

Xiong

Yue

et al. 2019

Materials Science and Engineering: A

View full text Add to dashboard Cite

Controlled cold rolling impacts on microstructure and mechanical properties of the rare earth Ce-modified SAF 2507 super duplex stainless steel (SDSS) are investigated towards a better application and development prospective over the pristine SDSS. Rolling was performed at room temperature with the deformation level in a range of 30% -90%. A large amount of dislocations into the ferrite phase turned out, and their density increased with the deformation. While, emergence of dislocation plugs group, ferrite grains get refined to nanometer scale during the deformation process. In addition to deformed bands within austenite, formation of α′-martensitic phases and significant increment in their volume fraction are detected and attributed to deformation-induced martensitic transformation. Elongation of the ferrite and austenite microstructures along the deformation direction under the action of high strain also resulted in fibers formation gradually. Correspondingly, significant increase in the strength index while decrement in the plasticity index are observed. Moreover, cold rolling deformation not only affects the tensile fracture morphology but also switches it from a typical ductile to a ductile and quasi-cleavage mixed fracture.

show abstract

Section: Methodsmentioning

confidence: 99%

Controlled cold rolling effect on microstructure and mechanical properties of Ce-modified SAF 2507 super duplex stainless steel

Zhou

Xiong

Yue

et al. 2019

Materials Science and Engineering: A

View full text Add to dashboard Cite

show abstract

“…This is called second austenite γ transformation because of the accompanying Ni enrichment. Moreover, the σ phase nucleated at either the γ/δ or δ/δ grain boundaries and grew into ferrite grains until the end of the transformation in Figure 10b [27].…”

Section: Discussionmentioning

confidence: 99%

“…It was found that the γ volume decreased and the δ volume increased from 2SS + 3 cycles to 2SS + 7 cycles, consistently with the thermodynamic prediction in the temperature range of 850 • C to 1000 • C in Figure 2, to achieve the ideal equilibrium ratio of δ:γ = 1:1 at 2SS + 7 cycles, as depicted in the green square in Figure 4. After the intersection point at 2SS + 7 cycles in Figure 4, the γ phase volume inversely increased and the δ volume decreased with increasing numbers of cycles (2SS + 13 cycles and 2SS + 20 cycles), causing the formation of small γ' grains, indicated by the fine dotted pink rectangle and purple rectangle in Figure 4, based on the δ phase eutectoid decomposition of δ → σ + γ' [5,27]. This so-called secondary γ' with high nickel and low chromium content is generated from the eutectoid decomposition of δ.…”

Section: The Microstructure Of Xrd and Ebsdmentioning

confidence: 99%

“…The total γ volume increase resulted from the eutectoid γ merging into the original γ phase grain, as indicated by the fine dotted pink narrow rectangle in Figure 4. rectangle and purple rectangle in Figure 4, based on the δ phase eutectoid decomposition of δ → σ + γ' [5,27]. This so-called secondary γ' with high nickel and low chromium content is generated from the eutectoid decomposition of δ.…”

Section: The Microstructure Of Xrd and Ebsdmentioning

confidence: 99%

See 1 more Smart Citation

Large Delta T Thermal Cycling Induced Stress Accelerates Equilibrium and Transformation in Super DSS

Chen

Yen

et al. 2020

Crystals

View full text Add to dashboard Cite

Based on the predicted phase diagram of super duplex stainless steel (DSS) calculated by Thermo-Calc, the maximum peak temperature 1100 °C was selected to ensure no σ phase existence. This target temperature fell into the two-phase solid solution (SS) region. A series of different thermal cycling tests were carried out with the notations of 2SS, 2SS + 3 cycles, 2SS + 7 cycles, 2SS + 13 cycles, and 2SS + 20 cycles. It was found that the trend of two-phase volume ratio variation by thermal cycling followed the predicted thermodynamic equilibrium trend. After 2SS + 7 cycles, the ratio of two-phase δ/γ tended toward the ideal 1:1. According to the electron backscatter diffraction (EBSD) analysis, the δ phase crystal orientation changed from the most frequent directions of <001> and <111> of the as-received sample to the most frequent orientation of <113> after two SS treatments. While the γ phase grain always remained at <101> orientation. The grain boundary misorientation angles of the γ grains were relatively stable, ranging from 53° to 63°, but those of the δ grains were widely distributed actively presuming the lattice rotation. The Kernel Average Misorientation (KAM) value of the local strain in face center cubic (fcc) γ grains was varied and greater than that of the body center cubic (bcc) δ phase, indicating that the former, with a large grain boundary misorientation had larger local deformation than the latter, which possesses wide random misorientation angle distribution.

show abstract

“…The other reason that affects the hot workability of duplex stainless steel is the precipitation of σ phase. The σ phase is hard and brittle, and it is the most harmful precipitation phase in steel, which can significantly reduce the plasticity of steel [6][7][8][9]. Amit [7] and Wang [10] et al believed that it is the slow cooling rate during forging that transforms δ phase to σ phase, and the precipitation of σ phase in this process damages the hot workability.…”

Section: Introductionmentioning

confidence: 99%

Effect of solution treatment on microstructure and properties of 00Cr32Ni7Mo3.5N

Chen

Ren

et al. 2021

Powder Metallurgy

View full text Add to dashboard Cite

00Cr32Ni7Mo3.5N parts were prepared by hot isostatic pressing (HIP) and forging process in this study. The effect of solution heat treatment on microstructure, mechanical properties and pitting resistance were investigated. Under solution treating at 1100°C, the phase constitution in HIP parts can be adjusted to comprise approximately 50% austenite (γ) and 50% ferrite (δ) phases with equiaxed structure, and this post-processing can meanwhile help to dissolve precipitated brittle σ phase. In comparison, the banded dual-phase structures in forged counterparts cannot be removed even after annealing at 1200°C. The desired phase proportion after solution treatment plus the equiaxed grains impart superior comprehensive performance to HIP parts with the tensile strength of 886 MPa, elongation of 48.0%, impact energy of 83 J, and pitting potential of 0.9659 V in neutral 3.5 wt-% NaCl solution. Based on this work, HIP seems to be a promising method to fabricate near-net-shape 00Cr32Ni7Mo3.5N parts.

show abstract

Study of Sigma Phase in Duplex SAF 2507

Cited by 15 publications

References 3 publications

Controlled cold rolling effect on microstructure and mechanical properties of Ce-modified SAF 2507 super duplex stainless steel

Controlled cold rolling effect on microstructure and mechanical properties of Ce-modified SAF 2507 super duplex stainless steel

Large Delta T Thermal Cycling Induced Stress Accelerates Equilibrium and Transformation in Super DSS

Effect of solution treatment on microstructure and properties of 00Cr32Ni7Mo3.5N

Contact Info

Product

Resources

About