POSCO Holdings Inc.
HIGH STRENGTH HOT-ROLLED STEEL SHEET HAVING EXCELLENT WORKABILITY, AND METHOD FOR MANUFACTURING THE SAME

Abstract:

Provided is a steel material that may be used for arms, frames, beams, brackets, reinforcing materials, etc. of chassis parts of a vehicle and, more specifically, to a high strength hot-rolled steel sheet having excellent workability and a method for manufacturing same. The steel sheet includes: by weight %, 0.1-0.15% of C, 2.0-3.0% of Si, 0.8-1.5% of Mn, 0.001-0.05% of P, 0.001-0.01% of S, 0.01-0.1% of Al, 0.7-1.7% of Cr, 0.0001-0.2% of Mo, 0.02-0.1% of Ti, 0.01-0.03% of Nb, 0.001-0.005% of B, 0.1-0.3% of V, 0.001-0.01% of N, and a balance of Fe and inevitable impurities, wherein tensile strength (TS) is 1180 MPa or more, a product (TS.times.E1) of tensile strength and elongation is 20,000 MPa % or more, and a product (TS.times.HER) of tensile strength and hole expandability is 30,000 MPa % or more.