The Webb Law Firm
High strength steel sheet and hot dip galvanized steel sheet having high ductility and excellent delayed fracture resistance and method for manufacturing the same
A cold rolled steel sheet and a hot dip galvanized steel sheet, which have high strength and elongation, such as a tensile strength of 980 MPa or more and an elongation of 28% or more, and excellent delayed fracture resistance, and manufacturing methods thereof. The cold rolled steel sheet has a composition including 0.05 to 0.3 weight percent C, 0.3 to 1.6 weight percent Si, 4.0 to 7.0 weight percent Mn, 0.5 to 2.0 weight percent Al, 0.01 to 0.1 weight percent Cr, 0.02 to 0.1 weight percent Ni and 0.005 to 0.03 weight percent Ti, 5 to 30 ppm B, 0.01 to 0.03 weight percent Sb, 0.008 weight percent or less S, balance Fe and impurities. The hot dip galvanized steel sheet has a hot dip galvanized layer or a hot dip galvannealed layer on the cold rolled steel sheet.
POSCO
C C C C C C C C C C C C C C
C21D C21D C21D C22C C21D C22C C21D C22C C22C C21D C22C C21D C21D C22C
additional inventional additional inventional additional inventional inventional inventional inventional additional inventional additional inventional inventional
Young Hoon Kwang Geun Seung Bok Jai Hyun
Jin Chin Lee Kwak