HIGH-STRENGTH STEEL SHEET AND METHOD FOR MANUFACTURING SAME

摘要

The present invention comprises: a hot rolling step in which a steel slab having a prescribed component composition is heated to 1100°C-1300°C, is hot rolled at a finishing rolling outlet side temperature of 800°C-1000°C, and then wound at an average winding temperature of 200°C-500°C, thereby forming a hot-rolled steel sheet; an acid cleaning treatment step in which an acid cleaning treatment is carried out on the hot-rolled steel sheet; and an annealing step in which the hot-rolled steel sheet is maintained at a temperature of 740°C-840°C for 10s-900s, then cooled at an average cooling speed of 5°C/s-50°C/s, to a cooling termination temperature of more than 350°C but not greater than 550°C, and is maintained for at least 10s at the temperature range of more than 350°C but not more than 550°C.