Facilitating the occurrence of dynamic recrystallization in plain extra low-carbon steel by warm asymmetric rolling

Abstract

The occurrence of dynamic recrystallization in warm rolling of plain extra-low carbon steel was examined by applying 75% thickness reduction in a single pass. The investigated temperature range was ambient to 700 °C. Results show apparently dynamic recrystallization remains absent in symmetric rolling below 600 °C. Nevertheless, dynamic recrystallization not only just occurs but accelerates as the condition of warm rolling changed from symmetric to asymmetric condition. The analysis of grain internal disorientations and geometrically necessary dislocation densities by High-angular Resolution on-axis Transmission Kikuchi Diffraction (HR-TKD) allowed to identify the type of dynamic recrystallization and its evolution through the warm temperature range. New grains formed by either continuous or discontinuous dynamic recrystallization are preferentially orientated according a typical shear texture up to 600 °C in the case of asymmetric rolling. Above 600 °C, dynamically recrystallized grains produce restrengthening in the rolling texture as well as in the overall texture.