POSCO Holdings Inc.
HIGH STRENGTH STEEL SHEET HAVING EXCELLENT FORMABILITY AND MANUFACTURING METHOD THEREOF

Abstract:

A high strength steel sheet including, by weight, C: 0.001% to 0.004%, Si: 0.5% or less (excluding 0%), Mn: 1.2% or less (excluding 0%), P: 0.005% to 0.12%, S: 0.01% or less, N: 0.01% or less, acid soluble Al: 0.1% or less (excluding 0%), Ti: 0.01% to 0.04%, a remainder of Fe, and unavoidable impurities, wherein the contents of Ti, N, and S satisfy the following Relationship 1, a ratio (b/a) of an average random intensity ratio (b) of an orientation group of (111) [1-10] to (111) [-1-12] to an average random intensity ratio (a) of an orientation group of (001) [1-10] to (110) [1-10] at a point t/4 (where t is a thickness of the steel sheet) in a thickness direction of the steel sheet is 2.3 or more, and a bake hardenability (BH) of the steel sheet is 4 MPa or more.