The dynamic characteristics and constitutive model of 1020 steel

Abstract

In this study, room-temperature quasi-static compressive tests and split Hopkinson tests based on the principles of plastic deformation were conducted on 1020 steel at strain rates ranging from 2000 to 4000 s−1 and temperatures ranging from 100 to 400°C in order to improve the quality of 1020 steel components formed by cold working and develop an accurate mathematical model for describing the dynamic characteristics of 1020 steel. The relationship between flow stress and strain, strain rate and temperature was obtained. The effects of various strain rates and temperatures on the flow stress of 1020 steel were investigated; the results show that the effect of strain rate and thermal softening is obvious, and a modified Johnson–Cook (JC) model and an original JC model were established and compared based on the experimental data. The results of comparisons between the measured and predicted flow stresses by the two models using statistical analysis indicate that the modified JC model describes the dynamic characteristics of 1020 steel more effectively than the original model does. In addition, the modified JC model yielded more consistent stress–strain relationship data under different strain rates and temperatures.