Microstructural Predictions Including Arbitrary Thermal Histories, Reaustenization and Carbon Segregation Effects

Oddy, A. S.; McDill, J.M.J.; Karlsson, L.

doi:10.1179/0008-4433(96)00001-8

Cited by 4 publications

(10 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[3] A separate kinetic model is used for the ferrite region that surrounds the pearlite. The diffusion-limited model for the austenitization of ferrite is very similar to others (Oddy et al, [15] Judd and Paxton, [5] and Molinder [4] ). The differences between the current model and the earlier models will be discussed after our model is presented.…”

Section: B Austenitization Kineticsmentioning

confidence: 86%

“…[16] It is assumed that the transformation from pearlite to austenite follows Avrami kinetics [18] and can be modeled as an additive reaction. [18] These assumptions result in the following differential equation for the reaction extent (Oddy et al, [15] and Jacot et al [19] ):…”

Section: B Austenitization Kineticsmentioning

confidence: 98%

“…Oddy et al [15] proposed a similar, but more complex, model to determine the carbon diffusion into the ferrite, which included two fitting constants. These fitting constants were expected to be similar in magnitude and near unity, yet they were determined to be an order of magnitude apart.…”

Section: B Austenitization Kineticsmentioning

confidence: 99%

“…The austenite carbon content is initially equal to the eutectoid value and then reduces as more of the ferrite region is transformed. Equation [15] only determines the density of the austenite at the average carbon content and must be modified to calculate the density of austenite for other carbon concentrations. This is done by using the following equation:…”

Section: Self-calibration Of the Phase Densitiesmentioning

confidence: 99%

“…Thus, the fraction transformed is not a linear function of the relative length change and cannot be directly inferred from a dilatation vs time/temperature record. In order to avoid this difficulty in the current work, the dilatation record from constant heating rate experiments was fit directly using temperature and composition-dependent densities coupled with a transformation model similar to that recently described by Oddy et al [15] From this direct fit, the fraction austenite versus the time/temperature path is derived. The model treats the formation of austenite from the pearlite/ferrite mixture as a two-part process, one describing the transformation of pearlite and one describing the growth of austenite into the proeutectoid ferrite.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

A method for extracting phase change kinetics from dilatation for multistep transformations: Austenitization of a low carbon steel

Dykhuizen

Robino

Knorovsky

1999

Metall Mater Trans B

View full text Add to dashboard Cite

This article describes the development of a method for determining phase change kinetics for multistep diffusion limited solid-state transformations from dilatation data. Since each step in a multistep reaction proceeds at a different rate, and the volume changes for the transformations are, in general, not equal, determination of the reaction kinetics from the dilatation data is not straightforward. Thus, a model is developed for the phase change process in which the transient dilatation is calculated based on the fractional extent of the various phases present. In this way, kinetic parameters are determined that allow the best match to the experimental data. However, both random and systematic experimental errors make reproduction of the experimental dilatation difficult. Therefore, a selfcalibration process is developed that uses portions of the dilatation data to obtain the density variation of the various phases with temperature to help correct for experimental uncertainties. This procedure also enables the model to be used in situations where accurate property data are not available. The model and procedures are applied to the formation of austenite in a pearlite/ferrite low carbon steel where the pearlite and ferrite regions transform at different rates. A single kinetic parameter set allows reproduction of transformation transients of significantly different heating rates. These parameters can then be used to describe the austenitization for any time-temperature path. Excellent agreement between the model and experimental data is shown.

show abstract

Section: B Austenitization Kineticsmentioning

confidence: 86%

Section: B Austenitization Kineticsmentioning

confidence: 98%

Section: B Austenitization Kineticsmentioning

confidence: 99%

Section: Self-calibration Of the Phase Densitiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

A method for extracting phase change kinetics from dilatation for multistep transformations: Austenitization of a low carbon steel

Dykhuizen

Robino

Knorovsky

1999

Metall Mater Trans B

View full text Add to dashboard Cite

show abstract

‘Flash’ Annealing in a Cold‐Rolled Low Carbon Steel Alloyed With Cr, Mn, Mo, and Nb: Part I ‐ Continuous Phase Transformations

Cerda

Vercruysse

Goulas

et al. 2018

steel research int.

View full text Add to dashboard Cite

The aim of the present work is to study the microstructure evolution of a cold‐rolled low carbon steel alloyed with Cr, Mn, Mo, and Nb during continuous heating. The formation of austenite and its further transformation is examined by means of peak annealing experiments at three different heating rates, followed by quenching. The effect of carbide‐forming alloying elements in the kinetics of austenite formation and decomposition is discussed with the aim of DICTRA calculations. Electron Probe Micro Analysis allows the detection of small compositional fluctuations within the microstructure, which are responsible for local changes in the mechanism of austenite formation. It is experimentally demonstrated that the temperature dependence of the austenite fraction is relatively insensitive to the heating rate. It is suggested that carbide‐forming alloying elements slow down the kinetics of austenite formation.

show abstract

Austenite decomposition during press hardening of a boron steel—Computer simulation and test

Åkerström

Oldenburg

2006

Journal of Materials Processing Technology

119

View full text Add to dashboard Cite

Microstructural Predictions Including Arbitrary Thermal Histories, Reaustenization and Carbon Segregation Effects

Cited by 4 publications

References 0 publications

A method for extracting phase change kinetics from dilatation for multistep transformations: Austenitization of a low carbon steel

A method for extracting phase change kinetics from dilatation for multistep transformations: Austenitization of a low carbon steel

‘Flash’ Annealing in a Cold‐Rolled Low Carbon Steel Alloyed With Cr, Mn, Mo, and Nb: Part I ‐ Continuous Phase Transformations

Austenite decomposition during press hardening of a boron steel—Computer simulation and test

Contact Info

Product

Resources

About