High toughness and high strength untempered steel and processing method thereof

摘要

The present invention is concerned about high toughness and high strength untempered steel having the mechanical properties equivalent to or better than those of tempered steel and processing method thereof, more particularly, the high toughness and high strength untempered steel having the tensile strength higher than 90 kgf/mm2 with the impact toughness higher than 5 kgf-m/cm2 in the KS 3 specimen, and processing method thereof.