Book ChapterDOI
Microstructural characterisation of steel heat-treated by the novel quenching and partitioning process
K. He,David V. Edmonds,John G. Speer,David K. Matlock,Fernando Rizzo +4 more
- pp 429-430
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TLDR
The Quenching and Partitioning (QPQP) process as discussed by the authors has exceptionally high carbon concentration of the austenite fraction, which is decoupled from the decomposition of the bainite.Abstract:
The Quenching and Partitioning (QP exceptionally high carbon concentration of austenite fraction, which is decoupled from austenite decomposition as compared with carbon partitioning during the bainite transformation; fast processing limited only by the rapid diffusion of carbon.read more
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Journal ArticleDOI
Quenching and Partitioning Steel Heat Treatment
Li Wang,John G. Speer +1 more
TL;DR: In this article, Dossett et al. investigated the relationship between properties and microstructures of Q&P steels subjected to various heat treatments and showed that the ultrahigh strength of X&P steel results from martensite laths, while its good ductility is attributed to TRIP-assisted behavior of retained austenite during deformation.
References
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Journal ArticleDOI
Carbon partitioning into austenite after martensite transformation
TL;DR: In this paper, a model is developed to describe the endpoint of carbon partitioning between quenched martensite and retained austenite, in the absence of carbide formation.
Journal ArticleDOI
Quenching and partitioning martensite-a novel steel heat treatment
TL;DR: In this paper, a novel concept for the heat treatment of martensite, different to customary quenching and tempering, is described, which can be used to generate microstructures with martensites/austenite combinations giving attractive properties.
Journal ArticleDOI
The bainite transformation in a silicon steel
Abstract: An experimental silicon steel has been used in a detailed kinetic and structural study of the bainite transformation in an attempt to resolve some of the controversies concerning the reaction mechanism. Distinct reaction ‘C’ curves and transformation mechanisms were observed for the upper and lower bainite reactions. The observed set of three minima in transformation kinetics were found to be incompatible with the solute drag explanation of the kinetic Bs temperature. Transmission electron microscopy indicated the growth of both upper and lower bainite by the propagation of displacive subunits, with adjacent nucleation in the latter case. Definite evidence for carbon supersaturation was obtained for the lower bainitic ferrite. The results are best explained in terms of a shear mechanism for the ferritic component of bainite rather than a ledge mechanism (as is observed in Widmanstatten ferrite growth). Carbide precipitation events were also characterized and the evidence suggested that precipitation resulted from the aging of a supersaturated matrix in lower bainite. The evidence also suggests that carbide precipitation events are of secondary importance to the essence of bainite formation. It was further proven that the concept of a metastable equilibrium1 controlling the transition from upper to lower bainite was not applicable to the present steel and indeed, if any metastable equilibrium does exist in any other steel, it does not constitute a general phenomenon and hence is not essential to the bainite transformation mechanism.