Improvement of strength and toughness for hot rolled low-carbon bainitic steel via grain refinement and crystallographic texture

• A high-efficient approach to improve mechanical properties of steel was reported.
• The strong <110>//RD texture was obtained by UFC following hot rolling.
• Effective grain size of the steel was refined to ~2.0 µm by the reported process.
• Mechanism of improving toughness was discussed.

Low-carbon bainitic steel with effective grain size of ~2.0 µm and strong <110>//RD (rolling direction) transformation texture was obtained by adopting ultra fast cooling following non-recrystallization rolling. The steel exhibited higher tensile strength of ~840 MPa and lower ductile-to-brittle transition temperature of ~−106 °C in comparison with the steel that had no distinct texture with effective grain size of ~4.5 µm. High intensity of {110} planes normal to the rolling direction were formed as a result of the strong {114}~{223}<110> transformation texture and effectively inhibited the main crack propagation by ductile fracture mechanism. The existing {100} planes parallel to the rolling plane led to the impact fracture delamination at −20~−100 °C, which improved the low temperature toughness.