Microstructure evolution and kinetic analysis of DM hot-work die steels during tempering

Zhou, Qingchun; Wu, Xiaochun; Shi, Nannan; Li, Junwan; Min, Na

doi:10.1016/j.msea.2011.04.024

Cited by 57 publications

(28 citation statements)

References 15 publications

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“…During tempering, the recovery of martensitic steel involves the precipitation and coarsening of carbides, as well as the rearrangement of dislocations inherited from quenching ( Ref 27,28). With regard to long-term tempering, the temper resistance of the steel strongly depends on the …”

Section: Temper Stabilitymentioning

confidence: 99%

Wear Resistance of H13 and a New Hot-Work Die Steel at High temperature

Chen

et al. 2016

J. of Materi Eng and Perform

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The friction and wear behaviors of a new hot-work die steel, SDCM-SS, were studied at high temperature under dry air conditions. The wear mechanism and microstructural characteristics of the SDCM-SS steel were also investigated. The results showed that the SDCM-SS steel had greater wear resistance compared with H13 steel; this was owed to its high oxidizability and temper stability. These features facilitate the generation, growth, and maintenance of a tribo-oxide layer at high temperature under relatively stable conditions. The high oxidizability and thermal stability of the SDCM-SS steel originate from its particular alloy design. No chromium is added to the steel; this ensures that the material has high oxidizability, and facilitates the generation of tribo-oxides during the sliding process. Molybdenum, tungsten, and vanadium additions promote the high temper resistance and stability of the steel. Many fine Mo 2 C and VC carbides precipitate during the tempering of SDCM-SS steel. During sliding, these carbides can delay the recovery process and postpone martensitic softening. The high temper stability postpones the transition from mild to severe wear and ensures that conditions of mild oxidative wear are maintained. Mild oxidative wear is the dominant wear mechanism for SDCM-SS steel between 400 and 700°C.

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Section: Temper Stabilitymentioning

confidence: 99%

Wear Resistance of H13 and a New Hot-Work Die Steel at High temperature

Chen

et al. 2016

J. of Materi Eng and Perform

Self Cite

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“…Johnson and Mehl 11 and Avrami 12-14 proposed a kinetic equation of solid state transformation simultaneously. Tempering transformation is solid state transformation controlled by diffusion and therefore its kinetic law can be written in the form of J-M-A-K type equation as follows 15,16 …”

Section: Tempering Kineticsmentioning

confidence: 99%

“…15 The values of ln D obtained by extrapolating the curves in Fig. 7 to the intersection at the vertical axis 6 Images (SEM) of samples isothermally tempered at a T th 5600uC, b T th 5620uC and c T th 5660uC respectively 7 Plots of ln ln 1 1{t…”

Section: Tempering Kineticsmentioning

confidence: 99%

Microstructure evolution and kinetics analysis during tempering of Mn–Ni–Mo nuclear power forging steel

Wang

Han

2013

International Heat Treatment and Surface Engineering

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The mechanical properties of Mn-Mo-Ni nuclear power forging steel can be affected greatly by tempering processes. In the present paper, scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and hardness measurements were employed to correlate property variation with the evolution of microstructure during tempering of an Mn-Mo-Ni steel. Kinetics analysis based on hardness measurements was applied to isothermal tempering at temperatures in the range 600-660uC. The hardness variations during tempering are explained by decomposition of retained austenite and martensite-austenite (M-A), precipitation and coarsening of carbides within bainitic ferrite, and recrystallisation of bainitic ferrite. According to the kinetics analysis, the tempering transformation activation energy has been calculated as about 101?4 kJ mol 21 , which indicates a mechanism of carbon diffusion within ferrite. Finally, the considerable precipitation and coarsening of carbides within bainitic ferrite have been observed only at high isothermal temperatures (generally equal to or above 660uC), indicating a high tempering resistance of the Mn-Mo-Ni steel.

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“…Usually, the working surface temperature of dies can get up to 550 • C, which is very close to the tempering temperature of die steel. Continuous evolution of the microstructure will occur and significantly affect the various properties of the die steel [1]. Actually, the cracks as a network are normally observed on the die surface, which results in more than 80% failure of hot-work dies [2].…”

Section: Introductionmentioning

confidence: 99%

Carbides Evolution and Tensile Property of 4Cr5MoSiV1 Die Steel with Rare Earth Addition

Liu

et al. 2017

Metals

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Studies of 4Cr5MoSiV1 die steel suggest that under appropriate conditions, additions of rare earth (RE) can enhance tensile property. This improvement is apparently due to the more uniform distribution of carbides and the enhancement of precipitation strengthening after RE additions. In this present work, the effect of the RE addition on the carbides evolution and tensile property of 4Cr5MoSiV1 steel with various RE contents (0, 0.018, 0.048 and 0.15 wt %) were systematically investigated. The two-dimensional detection techniques such as optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) were used to investigate the carbides evolution of as-cast, annealed and tempered with RE addition. The results indicated that the carbides in 4Cr5MoSiV1 steels were modified by adding the suitable amount of RE. The eutectic structure and coarse eutectic carbides were all refining and the morphology of the annealed carbides initiated change from strip shape to ellipsoidal shape compared with the unmodified test steel (0RE). In addition, the amount of the tempered M 8 C 7 carbides increased initially and then decreased with the alteration of RE addition from 0.018 to 0.15 wt %. Notably, the tensile test indicated that the average value of ultimate tensile strength (UTS) and elongation rate of 0.048RE steel increased slightly to 1474 MPa and 15%, higher than the 1452 MPa and 12% for the unmodified test steel (0RE), respectively. Such an addition of RE (0.048 wt %) would have a significant effect on the carbides evolution of as-cast, annealed and tempered and resulting in the tensile property of 4Cr5MoSiV1 die steel.

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Microstructure evolution and kinetic analysis of DM hot-work die steels during tempering

Cited by 57 publications

References 15 publications

Wear Resistance of H13 and a New Hot-Work Die Steel at High temperature

Wear Resistance of H13 and a New Hot-Work Die Steel at High temperature

Microstructure evolution and kinetics analysis during tempering of Mn–Ni–Mo nuclear power forging steel

Carbides Evolution and Tensile Property of 4Cr5MoSiV1 Die Steel with Rare Earth Addition

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