Severe tempering of bainite generated at low transformation temperatures

Severe tempering of bainite generated at low transformation temperatures

The response of a strong bainitic–steel to tempering at high temperatures is investigated, because a softened state is sometimes necessary during the manufacture of engineering components, prior to the final heat–treatment which hardens the material. Thermodynamic calculations conducted to determine the maximum temperature at which the steel could be annealed without forming austenite were foun...

Examination of carbon partitioning into austenite during tempering of bainite

The redistribution of carbon after tempering of a novel nanocrystalline bainitic steel consisting of a mixture of supersaturated ferrite and retained austenite has been analyzed by atom probe tomography. No direct evidence supporting the additional carbon enrichment of austenite beyond that initially achieved during the bainite heat treatment was obtained during subsequent tempering of this hig...

Kinetics of the bainite transformation

A theory is developed for the evolution of bainite as a function of time, temperature, chemical composition and austenite grain size. The model takes into account the details of the mechanism of transformation, including the fact that nucleation begins at the austenite grain surfaces, and that the growth of a sheaf occurs by the repeated nucleation of small platelets. Predictions made using the...

Mathematical Modelling of Bainite Transformation Kinetics

Steels with a mixed microstructure of allotriomorphic ferrite, bainitic ferrite, retained austenite and martensite have potentially good combinations of high strength and formability. This work describes a kinetic theory for the formation of bainite in steels where the precipitation of carbides is suppressed. The theory is based on the mechanism of transformation. It includes, for example, a nu...

Acceleration of Low - temperature Bainite