Strength and Ductility at High-speed Tensile Deformation of Low-carbon Steel with Ultrafine Grains

Tensile properties at various deformation speeds up to similar to 1500 mm/sec of low-carbon steel with elongated ultrafine grains were examined, focusing on both strength and ductility. Fine-grained samples were prepared by producing severe plastic deformation by caliber rolling. The ultrafine-grained samples showed an increase of elongation while maintaining high strength at a higher deformation speed. At a deformation speed of similar to 1500 mm/s, the absorbed energy exhibited by the fine-grained samples was as large as that of the conventional-grained sample, regardless of the difference in strength.