STEEL SHEET AND METHOD OF MANUFACTURING THE SAME

摘要

Disclosed are a steel sheet and a manufacturing method for the same, capable of satisfying properties of a low yield ratio by controlling alloying elements and process conditions. The manufacturing method for the steel sheet according to the present invention includes (a) a step of reheating a slab board in a slab reheating temperature (SRT) of 1150-1200°C; (b) a step of primarily rolling the reheated board in a recrystallization area; (c) a step of secondly rolling the primarily rolled board in a finishing rolling temperature (FRT) of 860-880°C in a non-recrystallization area; (d) a step of primarily cooling the secondly rolled board up to 450-500°C; (e) a step of cooling the primarily cooled board to be in 600-650°C due to the heat of the center of the thickness direction; and (f) a step of secondly cooling the cooled board up to less than 300°C. [Reference numerals] (AA) Start; (BB) End; (S110) Reheat a slab; (S120) Primary rolling; (S130) Secondary rolling; (S140) First cooling; (S150) Air cooling; (S160) Second cooling