Flow behavior and processing maps of high-strength low-alloy steel during hot compression.

Deformation behavior of a new kind of high-strength low-alloy steel was investigated by isothermal compression tests at temperatures of 800–1200 °C and strain rates of 0.01–10 s−1. The flow behavior of the steel was characterized through the analysis of true stress-strain curves. A relevant constitutive equation was established, and proved to be suitable by comparing experimental and calculated data under various deformation conditions. Processing maps based on the dynamic material model were constructed with strains of 0.3, 0.5 and 0.7. The maps showed that the optimal hot-working temperature range of the new steel was 1050–1200 °C, while the optimal strain rate range was 0.018–0.562 s−1, which was consistent with the microstructure of the deformed specimens. Dislocations and substructures under different deformation conditions were observed and analyzed by TEM. The results indicated that there were two kinds of DRX nucleation mechanisms during hot deformation. • The flow behavior of HSLA steel was studied. • The constitutive equation of the peak stress for HSLA steel was established. • The processing maps of HSLA steel at different strains were constructed. • Two DRX mechanisms were observed in this studied steel. [ABSTRACT FROM AUTHOR]