Microstructural evolution, precipitation and mechanical properties of hot rolled 27Cr-4Mo-2Ni ferritic steel during 800 °C aging

Lu, Hui-Hu; Guo, Hong-Kui; Luo, Yi; Liu, Zhen-Guang; Li, Wenqi; Li, Jianchun; Liang, Wei

doi:10.1016/j.matdes.2018.10.039

Cited by 40 publications

(15 citation statements)

References 36 publications

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“…It precipitates as fine particles along the ferrite grain boundaries and does not significantly grow due to the start of precipitation of r phase and the exhaustion of the available Nb [785,787]. Similar observations were made in 27Cr-4Mo-2Ni superferritic steel after hot rolling, solution treatment at 1050°C and/or aging between 600 and 800°C [789][790][791][792]. Increased Cr contents were found to promote the precipitation of r and Laves phase and to widen the precipitation temperature region of the Laves phase, but annealing at temperatures above 1000°C can result in complete dissolution of the detrimental phases [788].…”

Section: Superferritic Steels (C 25% Cr)supporting

confidence: 64%

“…At higher temperatures, detrimental embrittling intermetallic phases such as r (FeCr), v (Fe 36 Cr 12 M 10 ), and Laves phase (Mo,Nb,Ti)Fe 2 can precipitate. Due to the high Cr contents, the Cr-rich r phase is the most frequently observed precipitating phase, while the occurrence of Laves phase has only rarely been described [784][785][786][787][788][789][790][791][792][793]. In a typical superferritic alloy of composition 25Cr-(2-3)Mo-4Ni containing 0.3 wt% Nb, Laves phase was found to nucleate as first intermetallic phase during aging at 850°C.…”

Section: Superferritic Steels (C 25% Cr)mentioning

confidence: 99%

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Laves phases: a review of their functional and structural applications and an improved fundamental understanding of stability and properties

2020

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Laves phases with their comparably simple crystal structure are very common intermetallic phases and can be formed from element combinations all over the periodic table resulting in a huge number of known examples. Even though this type of phases is known for almost 100 years, and although a lot of information on stability, structure, and properties has accumulated especially during the last about 20 years, systematic evaluation and rationalization of this information in particular as a function of the involved elements is often lacking. It is one of the two main goals of this review to summarize the knowledge for some selected respective topics with a certain focus on non-stoichiometric, i.e., non-ideal Laves phases. The second, central goal of the review is to give a systematic overview about the role of Laves phases in all kinds of materials for functional and structural applications. There is a surprisingly broad range of successful utilization of Laves phases in functional applications comprising Laves phases as hydrogen storage material (Hydraloy), as magneto-mechanical sensors and actuators (Terfenol), or for wear- and corrosion-resistant coatings in corrosive atmospheres and at high temperatures (Tribaloy), to name but a few. Regarding structural applications, there is a renewed interest in using Laves phases for creep-strengthening of high-temperature steels and new respective alloy design concepts were developed and successfully tested. Apart from steels, Laves phases also occur in various other kinds of structural materials sometimes effectively improving properties, but often also acting in a detrimental way.

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Section: Superferritic Steels (C 25% Cr)supporting

confidence: 64%

Section: Superferritic Steels (C 25% Cr)mentioning

confidence: 99%

Laves phases: a review of their functional and structural applications and an improved fundamental understanding of stability and properties

2020

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“…The higher the chromium content in stainless steel, the better the corrosion resistance. Besides Cr, adding other appropriate alloyed elements is a very important method to improve the localized corrosion resistance of stainless steels [1][2][3]. Alloyed elements can be beneficial to corrosion resistance only if there is a certain chromium content in stainless steels.…”

Section: Introductionmentioning

confidence: 99%

Revisiting the effect of molybdenum on pitting resistance of stainless steels

et al. 2021

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As an important alloyed element to improve the localized corrosion resistance of stainless steels, Mo has been widely studied by researchers. This article reviews the mechanisms of the effect of Mo on localized corrosion. Two possible effects and corresponding experimental research are described respectively: Mo exists in the passive film as oxide and enhances the film stability (manifesting as lower nucleation probability of localized corrosion and longer delay time of breakdown of the passive film); Mo affects dissolution kinetics and inhibits active dissolution current density (manifesting as smaller metastable pitting current density and size). Then some contradictory results are discussed by considering the pitting model proposedrecently. Strictly speaking, none of the existing experimental results can deny the effect of Mo on the passive film or on the dissolution kinetics. It is reasonable to believe that Mo affects the entire process of localized corrosion rather than a single reaction. Finally, some possible research suggestions are put forward.

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“…However, the problem with increasing Cr content and adding Al is that this can lead to a formation of the M 23 C 6 -type (M=Cr and Fe) carbides and AlN precipitates, the coarsening rate of which will accelerate at high temperatures and in turn significantly affect the changes in mechanical properties during hot deformation [5][6][7][8]. FHSS exhibits the poor formability and abnormal grain coarsening at high temperatures [9,10]. Therefore, controlling the precipitates and hindering the grain growth is very significant for improving product properties.…”

Section: Introductionmentioning

confidence: 99%

Microstructural evolution and precipitation behavior of the 0.1C-18Cr-1Al-1Si ferritic heat-resistant stainless steel during hot deformation

Zhang

Zou

Wei

et al. 2020

Mater. Res. Express

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The 0.1C-18Cr-1Al-1Si ferritic heat-resistant stainless steel has attracted considerable attention to high-temperature applications due to its favorable combination of creep and oxidation resistance. In this paper, the microstructural evolution and precipitation behavior of the 0.1C-18Cr-1Al-1Si ferritic heat-resistant stainless steel is studied from the compression deformation data in the temperature range of 850°C-1050°C and the strain rate range of 0.01-1 s −1 . Experimental results demonstrate that higher temperatures and lower strain rates enhance the dynamic recrystallization (DRX) process with remarkable effectiveness. The main precipitates are proved as the AlN phases and the (Cr,Fe) 23 C 6 carbides during hot deformation. With an increase in the deformation temperature, the size of (Cr,Fe) 23 C 6 and AlN gradually increases, and volume fraction gradually decreases. When the strain rate decreases, the average size and volume fraction of (Cr,Fe) 23 C 6 and AlN gradually increase. At the lower temperatures, the occurrence of dynamic recrystallization (DRX) is strongly influenced by (Cr,Fe) 23 C 6 formed on the grain boundaries, mainly because it causes a pinning effect, which hinders the movement of dislocations and delays the occurrence of the DRX.

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Microstructural evolution, precipitation and mechanical properties of hot rolled 27Cr-4Mo-2Ni ferritic steel during 800 °C aging

Cited by 40 publications

References 36 publications

Laves phases: a review of their functional and structural applications and an improved fundamental understanding of stability and properties

Laves phases: a review of their functional and structural applications and an improved fundamental understanding of stability and properties

Revisiting the effect of molybdenum on pitting resistance of stainless steels

Microstructural evolution and precipitation behavior of the 0.1C-18Cr-1Al-1Si ferritic heat-resistant stainless steel during hot deformation

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Microstructural evolution, precipitation and mechanical properties of hot rolled 27Cr-4Mo-2Ni ferritic steel during 800 °C aging

Cited by 40 publications

References 36 publications

Laves phases: a review of their functional and structural applications and an improved fundamental understanding of stability and properties

Laves phases: a review of their functional and structural applications and an improved fundamental understanding of stability and properties

Revisiting the effect of molybdenum on pitting resistance of stainless steels

Microstructural evolution and precipitation behavior of the 0.1C-18Cr-1Al-1Si ferritic heat-resistant stainless steel during hot deformation

Contact Info

Product

Resources

About

Microstructural evolution, precipitation and mechanical properties of hot rolled 27Cr-4Mo-2Ni ferritic steel during 800 °C aging