The Prediction of the Mechanical Properties for Hot-Rolled Nb Micro-Alloyed Dual-Phase Steel Based on Microstructure Characteristics

Because wheel manufacturing requires dual-phase (DP) 590 steel with different thickness specifications, it is necessary to produce DP590 steel with good mechanical property stability through a controlled cooling process. According to the volume fraction of ferrite and martensite and the grain size of ferrite in DP590 steel with different plate thicknesses under industrial production conditions, the effects of strengthening and toughening mechanisms, such as fine grain strengthening and phase transformation strengthening, on mechanical properties are considered, and a prediction model of the microstructure-property relationship of DP590 steel is established. On this basis, the effects of thickness and processing parameters on the grain size and fraction of ferrite are analyzed, which show that the evolution of ferrite accord with physical metallurgy principles. Three DP590 steels are rolled by using the established microstructure-property relationship model, and the results show that the predicted results of the model are in good agreement with the experimental values.