Abstract: The present disclosure relates to a high-strength steel and a method of manufacturing the same. Slab with specific composition is subjected to a rolling process and a heat treatment process with specific conditions for changing the metallographic structure of the obtained steel. The obtained steel includes at least 95% tempered martensite, and has a high tensile strength and a high yield strength.

Abstract: A method for manufacturing a high-strength and high-ductility steel includes steps in which an alloy steel is provided. The method continues with step in which the alloy steel is hot rolled, so that the microstructure of the alloy steel includes austenite, bainite and martensite. The method continues with step in which the hot-rolled alloy steel is annealed, so as to decompose bainite and martensite structures of the alloy steel into ferrite and austenite structures. The method continues with step in which the annealed alloy steel is cold rolled. The method continues with step in which the cold-rolled alloy steel is annealed, so as to manufacture a high-strength and high-ductility steel in a phase with 50% to 70% of residual austenite.

Abstract: A method for manufacturing a high-strength and high-ductility steel includes steps in which an alloy steel is provided. The method continues with step in which the alloy steel is hot rolled, so that the microstructure of the alloy steel includes austenite, bainite and martensite. The method continues with step in which the hot-rolled alloy steel is annealed, so as to decompose bainite and martensite structures of the alloy steel into ferrite and austenite structures. The method continues with step in which the annealed alloy steel is cold rolled. The method continues with step in which the cold-rolled alloy steel is annealed, so as to manufacture a high-strength and high-ductility steel in a phase with 50% to 70% of residual austenite.