Austenitization during intercritical annealing of an Fe-C-Si-Mn dual-phase steel

Yi, Joon-Jeong; Kim, In Sup; Choi, Hyung Sup

doi:10.1007/bf02670328

Cited by 46 publications

(12 citation statements)

References 9 publications

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“…f s is only a function of temperature. This is consistent with existing studies on dual-phase steels conducted by Yi et al (1985) and Asadi…”

Section: Saturated Volume Fractionsupporting

confidence: 93%

“…A e1 and A e3 are the starting and finishing temperatures of austenite formation for a proeutectoid steel in the equilibrium state. If the steel is soaked at a temperature between A e1 and A e3 , which is termed the intercritical region, only partial austenitization can be achieved, which has been proved by the studies of Yi et al (1985) and Asadi Asadabad et al (2008). The equilibrium state is a mixture of austenite and ferrite phases (α + γ).…”

Section: Introductionmentioning

confidence: 99%

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Experimental characterisation of the effects of thermal conditions on austenite formation for hot stamping of boron steel

Lin

Balint

et al. 2016

Journal of Materials Processing Technology

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The formation of austenite in manganese-boron steels during selective heat treatment has great significance in the application of innovative hot stamping processes. Heat treatment tests were designed according to the thermal cycle of industrial heating and hot stamping processes and were conducted on a Gleeble 3800 thermomechanical testing system. Specimens were subjected to non-isothermal (heating rates: 1K/s-25K/s) and isothermal (soaking temperatures: 1023K-1173K) temperature profiles. A high-resolution dilatometer was employed to detect the dimensional change of the specimens associated with austenitization. The dilatometric measurement was quantitatively related to the volume fraction of austenite. By analysing the evolution curves of austenite fraction, the effects of heating rate and temperature on the progress of austenite formation under both non-isothermal and isothermal conditions were investigated and characterised, improving the current understanding of the mechanisms that control austenite formation in manganese-boron steels. Imperial College London Reviewer #1: General:This submission presents new and significant results on austenite formation during heating cycles for a commercial Mn-B steel (22MNB5). The data and insights presented will be valuable in the design of selective heating and quenching processes for hot stamping of this steel grade. However, the Discussion is deficient. The need to analyse the (same) dilatometer data several different ways is not obvious. See responses to the specific comments below -in particular, see the response to specific comment 5. Specific:1. p.6: Section 2 is a lengthy description of 'textbook material'. It should be deleted and replaced with a brief summary of the issues/knowledge gaps which were addressed in the present study. This revised summary should be included in Section 1. Section 2 has been reduced and incorporated into a revised Section 1 (p. 6-8). The information that remains is necessary for later discussion Thank you for these corretions. All have been updated according to the suggestions. The comments from Reviewer #3:In order to gain a better understanding of the kinetics of the austenite formation in boron steels, in this work the formation of austenite in a manganese-boron steel has been investigated by the authors through dilatometry and theoretical analysis. The authors have conducted heat treatment tests on a Gleeble 3800 thermomechanical testing system. Specimens were subjected to non-isothermal heating rates (1K/s, 5 K/s and 25K/s) and different isothermal soaking temperatures (1023K, 1073K,1123K and1173K) . A high resolution dilatometer was employed to detect the dimensional change of the specimens associated with austenitization and a method was proposed to quantitatively relate the dilatometric measurement to the volume fraction of austenite. The effects of heating rate and soaking temperature on the progress of austenite formation under both non-isothermal and isothermal conditions were investigated by analyzing the evolu...

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“…f s is only a function of temperature. This is consistent with existing studies on dual-phase steels conducted by Yi et al (1985) and Asadi…”

Section: Saturated Volume Fractionsupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Experimental characterisation of the effects of thermal conditions on austenite formation for hot stamping of boron steel

Lin

Balint

et al. 2016

Journal of Materials Processing Technology

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“…4 closely resemble the one presented in Ref. [14] obtained after partial austenitisation of a martensitic microstructure. In their work, the martensite present in the initial microstructure undergoes carbide precipitation along martensite lath and packet boundaries during the heating prior to the partial austenitisation, preventing the annihilation of the tangled dislocation substructure inside the martensite laths and keeping the lath boundaries.…”

Section: Formation Of Intercritical Microstructuressupporting

confidence: 79%

“…5a shows that the microstructure obtained after heating to 710 • C (below A c1 ), consists of ferrite, a small amount of untempered martensite (formed during the 3 s of isothermal holding, which was also confirmed by dilatometry) and partially tempered martensite that was present in the initial microstructure and that is probably containing precipitation of carbides in martensite interlath positions, as described in Ref. [14]. At higher magnifications some carbide precipitation could be observed in martensite/martensite boundaries.…”

Section: Formation Of Intercritical Microstructuresmentioning

confidence: 84%

New low carbon Q&P steels containing film-like intercritical ferrite

Santofimia

Minh

Zhao

et al. 2010

Materials Science and Engineering: A

165

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“…Then, the austenite nucleated inside the pearlite colonies and on the pearlite colony boundaries. Meanwhile austenite was nucleated on the ferrite-ferrite grain boundaries 22,27,28 . Besides, the carbides in the ferrite grains also offered nucleation sites for austenite in the present study.…”

Section: Dual-phase Microstructuresmentioning

confidence: 99%

Effect of initial microstructures on the properties of Ferrite-Martensite Dual-Phase pipeline steels with Strain-Based design

Zuo

et al. 2012

Mat. Res.

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This study aims to investigate the effect of initial microstructures on the properties of ferritemartensite dual-phase pipeline steels with strain-based design. For this purpose, the as-received acicular ferrite steels were first austenitized at 920 °C for 15 minutes followed by air cooling and water quenching to produce ferrite-pearlite and ferrite-martensite microstructure, respectively. Subsequently, the steels with ferrite-pearlite, ferrite-martensite and as-received acicular ferrite microstructure were intercritically annealed at 820 °C for 10 minutes followed by water quenching to produce three different ferrite-martensite dual-phase microstructures. Tensile tests, Vickers hardness and Charpy impact tests were carried out to investigate the mechanical properties. Scanning electron microscope was used to analyze the microstructures and tensile fractographs. The results showed that all the tensile specimens of these three different ferrite-martensite dual-phase steels fractured in ductile mode, however, their microstructures and mechanical properties varied significantly. By contrast, the ferrite-martensite dual-phase steel derived from acicular ferrite initial microstructure had optimal combination of the strength, toughness and deformability, which provided a good candidate for the pipeline steels with strain-based design used in severe geological environments.

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Austenitization during intercritical annealing of an Fe-C-Si-Mn dual-phase steel

Cited by 46 publications

References 9 publications

Experimental characterisation of the effects of thermal conditions on austenite formation for hot stamping of boron steel

Experimental characterisation of the effects of thermal conditions on austenite formation for hot stamping of boron steel

New low carbon Q&P steels containing film-like intercritical ferrite

Effect of initial microstructures on the properties of Ferrite-Martensite Dual-Phase pipeline steels with Strain-Based design

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