公开(公告)号：US12180556B2

公开(公告)日：2024-12-31

申请号：US18025836

申请日：2021-09-13

Applicant: POSCO CO., LTD

Inventor： Tae-Jin Song ,  Sung-Il Kim ,  Chang-Sik Choi

IPC: C21D8/02 ,  C21D9/46 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/60 ,  C23C2/06 ,  C23C2/40 ,  C23G1/00

Abstract: Provided are a hot rolled steel sheet having excellent crashworthiness and a method for manufacturing same. The hot rolled steel sheet of the present invention contains, in weight %, 0.05-0.13% of carbon (C), 0.2-2.0% of silicon (Si), 1.3-3.0% of manganese (Mn), 0.01-0.1% of aluminum (Al), 0.001-0.05% of phosphor (P), 0.001-0.05% of sulfur (S), 0.001-0.02% of nitrogen (N), and the balance being Fe and other inevitable impurities, and has a steel microstructure comprising, in area %, 55% or more of bainitic ferrite, 10% or more of a martensite/austenite composite phase (MA), the sum of the bainitic ferrite and the martensite/austenite composite phase (MA) being 95% or more, and the remaining total being less than 5% of granular ferrite, retained austenite, and carbides.

公开(公告)号：US20250051870A1

公开(公告)日：2025-02-13

申请号：US18712125

申请日：2022-11-22

Applicant: POSCO CO., LTD

Inventor： Tae-Jin Song ,  Joo-Hyun Ryu ,  Je-Woong Lee

IPC: C21D9/46 ,  C21D1/18 ,  C21D6/00 ,  C21D8/02 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/12 ,  C22C38/14 ,  C22C38/22 ,  C22C38/26 ,  C22C38/28 ,  C22C38/32 ,  C22C38/38

Abstract: The present invention relates to a hot-rolled steel sheet that can be suitably applied to an automobile chassis structure member or the like and, more specifically, to an ultrahigh-strength hot-rolled steel sheet having tensile strength of 1180 MPa or more, excellent formability, and uniform material distribution in the steel sheet, and a manufacturing method therefor.

公开(公告)号：US11970749B2

公开(公告)日：2024-04-30

申请号：US18171305

申请日：2023-02-17

Applicant: POSCO CO., LTD

Inventor： Tae-Jin Song ,  Jeong-Eun Kim ,  Chang-Sik Choi

IPC: C21D8/02 ,  C21D9/46 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/12 ,  C22C38/14

CPC classification number: C21D8/0226 ,  C21D8/0205 ,  C21D8/0215 ,  C21D8/0247 ,  C21D9/46 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/12 ,  C22C38/14 ,  C21D2211/001

Abstract: Provided is a method of manufacturing a hot rolled steel sheet having excellent formability and fatigue properties, including: preparing a slab including, by weight %, 0.3 to 0.8% of carbon C, 13 to 25% of manganese (Mn), 0.1 to 1.0% of vanadium (V), 0.005 to 2.0% of silicon (Si), 0.01 to 2.5% of aluminum (Al), 0.03% or less of phosphorus (P), 0.03% or less of sulfur (S), 0.04% or less (excluding 0%) of nitrogen (N), and a remainder of iron (Fe) and inevitable impurities; heating the slab to 1050 to 1250° C.; finish rolling, the slab heated in the heating, at a temperature of not lower than a recrystallization temperature of a region having an average V concentration and not higher than a recrystallization temperature of a region having twice the average V concentration, to obtain a hot rolled steel sheet; and coiling the hot-rolled steel sheet at 50 to 700° C.