Diffusion-controlled phase transformations in steels. Theory and applications

A semi-empirical approach to the application of transformation theory to the prediction of mechanical properties of low alloy steels is described. Isothermal theories of particle, plate and lamellar growth due to Hillert and others are synthesized and calibrated within multicomponent constitutional and cooling constraints to predict tempering, isothermal and continuous cooling diagrams. From these, mechanical properties and residual stress-strain distributions can be usefully estimated. Calibration of the formulas to large historical data sets allows very accurate computational predictions to be made. It is argued that our particular compromise between theory and empiricism is optimal with respect to the requirements of heat treat technology