Tempering of medium- and high-carbon martensites

Samuel, F. H.; Hussein, A. A.

doi:10.1016/0026-0800(82)90030-1

Cited by 17 publications

(7 citation statements)

References 15 publications

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“…[2][3][4] Hence, tempering of formerly created martensite is possible in regular traffic, together with compressive stress in the wheel/rail interface. In an earlier study, rapid tempering of martensite without prestress showed a strong softening taking place greater than about 150-200uC (associated with the first stages of tempering 5,6 ), essentially instantaneous and as a function only on maximum peak temperature reached during the tempering process. 7 In the present study, monotonic stress-strain response has been investigated for as quenched martensite (and pearlite) when flash heated under simultaneous constant compressive stress.…”

Section: Introductionmentioning

confidence: 85%

Rapid thermomechanical tempering of iron–carbon martensite

Cvetkovski

Ahlström

Persson

2014

Materials Science and Technology

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Tempering of martensite under simultaneous compressive stress has been studied within the temperature range of 20-400uC. Resistive heating was utilised to obtain rapid heating and cooling cycles of a few seconds. Material was obtained from a medium carbon pearlitic railway wheel steel, quench hardened to obtain martensitic structure. Greater than y150uC dilatation effects where observed below the global yielding point of the material. Microstraining around dislocations in the body centred tetragonal crystallographic structure or viscous flow at higher temperatures was a probable explanation to this material behaviour. Hence, external stress may have an important influence on the tempering progression of martensitic steel. The trials also showed that tempering of martensite progresses fast, is near instantaneous and is independent of the presence of external stress or not.

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Section: Introductionmentioning

confidence: 85%

Rapid thermomechanical tempering of iron–carbon martensite

Cvetkovski

Ahlström

Persson

2014

Materials Science and Technology

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“…For high-carbon steel, Wang et al [27] reported that HMF could enhance the decomposition of the retained austenite in M50 steel during tempering at 200-530 • C. From these studies, it is realized that HMF has the capacity to modify the microstructure and performance of steels during tempering. However, for high-carbon steels, tempering at a relatively high temperature (such as 600 • C) can significantly cause the recovery of the matrix and the coarsening of carbides [30], finally obtaining TS structures [6,8]. The majority of the previous studies regarding tempering in HMF have focused on the tempering of steels at relatively lower temperatures.…”

Section: Introductionmentioning

confidence: 99%

Effect of High Magnetic Field in Combination with High-Temperature Tempering on Microstructures and Mechanical Properties of GCr15 Bearing Steel

Chen

Zhu

et al. 2022

Metals

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The microstructures and mechanical properties of GCr15 bearing steel after high-temperature tempering with and without a 5 T high magnetic field (HMF) were investigated. It was found that the application of the HMF at the stage of high-temperature tempering slowed down the growth of the tempered sorbite (TS) structures, increased the density of the carbides, and reduced the carbide size and the volume fraction. XRD diffraction patterns showed that the HMF resulted in a higher dislocation density. Hardness testing indicated that the HMF led to an increase in the Vickers hardness in the tempered sample. It is inferred that the change in carbide size stems from the reduction in nucleation barrier in the HMF and the increase in dislocation density originates from the interaction between dislocations and carbides. Additionally, the decrease in diffusivity in the HMF also contributes to the reduction in the size of TS structures and the refinement of carbides. This work demonstrates that high-temperature tempering with an HMF can slow down the growth of TS microstructures in GCr15 bearing steel, control the carbide size, and improve Vickers hardness, which provides a new heat treatment method to regulate the microstructure and properties of GCr15 bearing steel.

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“…Upon tempering of quenched high-carbon martensitic steels, the detwinning process and the formation of the carbides normally start at a relatively low-temperature: approximately 100 to 400 °C 7 , 14 – 17 . However, in low-carbon steels, the carbides (mainly cementite) normally form after tempering at approximately 400 °C 9 , 18 .…”

Section: Introductionmentioning

confidence: 99%

“…Previous studies mainly focused on carbide formation during the tempering process, and most of the studied alloys were not simply Fe–C binary alloys 3 ; and less attention has been paid to the morphology change of twinning structures during tempering. Some studies have revealed that the twinning structure vanishes and dislocations change into subgrain boundaries during tempering 7 . Recently, a new mechanism of the microstructural evolution has been proposed that the twinned martensite can be treated as freshly formed martensite immediately after martensitic transformation; and that the other structure can be regarded as the result of tempering (auto-tempering or post-tempering) 9 , 10 .…”

Section: Introductionmentioning

confidence: 99%

In situ heating TEM observations on carbide formation and α-Fe recrystallization in twinned martensite

Liu

Man

Yin

et al. 2018

Sci Rep

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The microstructural evolution of twinned martensite in water-quenched Fe–1.6 C (wt.%) alloys upon in situ heating was investigated using transmission electron microscopy (TEM). In the as-quenched samples, a high density of a body-centred cubic (bcc) {112} 〈111〉 -type twinning structure exists in the martensite structure. Upon in situ heating to approximately 200–250 °C, carbides (mainly θ-Fe3C cementite) accompanying a detwinning process were observed only in the originally twinned region. The carbides were absent in the originally untwinned (twin-free) region. The experimental results have suggested that the formation of the carbides depends on the twinning-boundary ω-Fe metastable phase, which can be stabilised by interstitial carbon atoms. When the specimens were heated, the twinning-boundary ω-Fe(C) transformed into carbide (mainly θ-Fe3C cementite) particles on the original {112} twinning planes. Further heating resulted in substantial recrystallisation of α-Fe fine particles, which formed immediately after martensite transformation. The results presented here should be helpful in understanding the microstructural evolution of various carbon steels.

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Tempering of medium- and high-carbon martensites

Cited by 17 publications

References 15 publications

Rapid thermomechanical tempering of iron–carbon martensite

Rapid thermomechanical tempering of iron–carbon martensite

Effect of High Magnetic Field in Combination with High-Temperature Tempering on Microstructures and Mechanical Properties of GCr15 Bearing Steel

In situ heating TEM observations on carbide formation and α-Fe recrystallization in twinned martensite

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