Identification and quantification of martensite in ferritic-austenitic stainless steels and welds

Baghdadchi, Amir; Hosseini, Vahid A.; Karlsson, Leif

doi:10.1016/j.jmrt.2021.09.153

Cited by 23 publications

(7 citation statements)

References 42 publications

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“…The corresponding phase map shown in Figure 1 b displays a small fraction of α′-martensite, ~3%, that coexists with the austenitic matrix. This martensite formation in the initial structure of MMn–SS is attributable to the mechanical polishing, which promoted strain, and consequently martensite was induced, as reported in the literature [ 32 , 33 ].…”

Section: Resultssupporting

confidence: 52%

Microstructural Evolution and Mechanical Performance of Two Joints of Medium-Mn Stainless Steel with Low- and High-Alloyed Steels

et al. 2023

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In this work, 2 mm thick medium-Mn austenitic stainless steel (MMn–SS) plates were joined with austenitic NiCr stainless steel (NiCr–SS) and low-carbon steel (LCS) using the gas tungsten arc welding technique. A precise adjustment of the welding process parameters was conducted to achieve high-quality dissimilar joints of MMn–SS with NiCr–SS and LCS. The microstructural evolution was studied using laser scanning confocal and electron microscopes. Secondary electron imaging and electron backscatter diffraction (EBSD) techniques were intensively employed to analyze the fine features of the weld structures. The mechanical properties of the joints were evaluated by uniaxial tensile tests and micro-indentation hardness (HIT). The microstructure of the fusion zone (FZ) in the MMn–SS joints exhibited an austenitic matrix with a small fraction of δ-ferrite, ~6%. The tensile strength (TS) of the MMn–SS/NiCr–SS joint is significantly higher than that of the MMn–SS/LCS joint. For instance, the TSs of MMn–SS joints with NiCr–SS and LCS are 610 and 340 MPa, respectively. The tensile properties of MMn–SS/LCS joints are similar to those of BM LCS, since the deformation behavior and shape of the tensile flow curve for that joint are comparable with the flow curve of LCS. The HIT measurements show that the MMn–SS/NiCr–SS joint is significantly stronger than the MMn–SS/LCS joint since the HIT values are 2.18 and 1.85 GPa, respectively.

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Section: Resultssupporting

confidence: 52%

Microstructural Evolution and Mechanical Performance of Two Joints of Medium-Mn Stainless Steel with Low- and High-Alloyed Steels

et al. 2023

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“…As the ferrite and martensite phases look similar on the SEM images, no difference was observed in the matrix structure. [ 26 ] Therefore, to distinguish the matrix of the two samples, the samples were color‐etched using the LePera etchant and observed by the OM (Figure 2c,d). When steels are etched with the LePera etchant, different colors appear depending on the phase.…”

Section: Resultsmentioning

confidence: 99%

The Effect of V/C Ratio on the Phase Formation Behavior in Vanadium Carbide‐Based Tool Steel Fabricated through Powder Metallurgy

Park,

Kim,

Jun

et al. 2023

steel research int.

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This study investigates phase formation behavior by considering the vanadium (V) to carbon (C) ratio in vanadium carbide‐based tool steel. The V/C ratios are controlled by changing the V content. The samples with the V/C ratio of 4.78 and 6.12 are first prepared through gas atomization with a form of powder and then turned into bulk forms through hot isostatic pressing. The bulk samples are annealed at 1070 °C and then quenched. The hardness values of the 4.78V/C and 6.12V/C samples are 50.7 and 17.3 HRC, respectively. Phases of each sample are analyzed to confirm the reason for the hardness difference. The α′‐martensite phase is formed in the matrix of the 4.78V/C sample, whereas the matrix of the 6.12V/C sample is the α‐ferrite phase. Thermodynamic calculations and high‐temperature phase analysis are performed to examine the difference in the phase formation. In the 4.78V/C sample, the γ‐austenite phase is formed at 1070 °C, which transforms to the α′‐martensite phase during cooling in the heat treatment process. Meanwhile, the 6.12V/C sample has no austenite phase at 1070 °C, so martensitic transformation does not occur. These analyses confirm that it is crucial to control the phase formation by controlling the contents of V and C with an appropriate ratio.

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“…As it shows, 8 parallel beads were deposited in each layer, and thereafter, layers were added until the block was fabricated. In this macrograph etched with modified Beraha reagent, ferrite is the dark phase and austenite is the bright phase [29][30][31]. As can be seen, there was a periodic bead-to-bead microstructure in each layer.…”

Section: Overviewmentioning

confidence: 92%

Wire laser metal deposition of 22% Cr duplex stainless steel: as-deposited and heat-treated microstructure and mechanical properties

et al. 2022

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Duplex stainless steel (DSS) blocks with dimensions of 150 × 70x30 mm3 were fabricated by Laser Metal Deposition with Wire (LMDw). Implementation of a programmable logic control system and the hot-wire technology provided a stable and consistent process producing high-quality and virtually defect-free deposits. Microstructure and mechanical properties were studied for as-deposited (AD) material and when heat-treated (HT) for 1 h at 1100 °C. The AD microstructure was inhomogeneous with highly ferritic areas with nitrides and austenitic regions with fine secondary austenite occurring in a periodic manner. Heat treatment produced a homogenized microstructure, free from nitrides and fine secondary austenite, with balanced ferrite and austenite fractions. Although some nitrogen was lost during LMDw, heat treatment or reheating by subsequent passes in AD allowed the formation of about 50% austenite. Mechanical properties fulfilled common requirements on strength and toughness in both as-deposited and heat-treated conditions achieving the highest strength in AD condition and best toughness and ductility in HT condition. Epitaxial ferrite growth, giving elongated grains along the build direction, resulted in somewhat higher toughness in both AD and HT conditions when cracks propagated perpendicular to the build direction. It was concluded that high-quality components can be produced by LMDw and that deposits can be used in either AD or HT conditions. The findings of this research provide valuable input for the fabrication of high-performance DSS AM components. Graphical Abstract

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Identification and quantification of martensite in ferritic-austenitic stainless steels and welds

Cited by 23 publications

References 42 publications

Microstructural Evolution and Mechanical Performance of Two Joints of Medium-Mn Stainless Steel with Low- and High-Alloyed Steels

Microstructural Evolution and Mechanical Performance of Two Joints of Medium-Mn Stainless Steel with Low- and High-Alloyed Steels

The Effect of V/C Ratio on the Phase Formation Behavior in Vanadium Carbide‐Based Tool Steel Fabricated through Powder Metallurgy

Wire laser metal deposition of 22% Cr duplex stainless steel: as-deposited and heat-treated microstructure and mechanical properties

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