Simple method for tailoring the optimum microstructures of high-strength low-alloyed steels by the use of constitutive equation

A simple approach for tailoring the microstructure to meet the property requirements of low carbon steels is studied with the material constants of the Swift equation. Experimental data of the specimens subjected to various chemical compositions and rolling conditions were used to elucidate the relationship among the microstructures, the tensile properties, and the material constants of the Swift equation. This relationship reveals that the material constants of the Swift equation are closely related to the microstructural features of low carbon steels, and in particular constant b can be expressed as a function of the volume fraction of the constituent phases. The approach proposed in this study includes (i) the determination of appropriate range of constant b to meet the required properties and (ii) the selection of the optimum microstructures corresponding to the determined b values. Since this simple approach can provide a guidance in how to control the microstructure to acquire target properties and link microstructural features with macroscopic constitutive behavior, it is very useful for the development of new advanced steels and to save time and production cost.