IP Library › Granted Patent US 12,516,394
Granted Patent B2
US 12,516,394 · App. 17/311,219 · Granted Jan 6, 2026

Plated steel sheet for hot press forming having excellent impact properties after hot press forming, hot press formed member, and manufacturing methods thereof

Inventors: Seong-Woo Kim (Gwangyang-si, KR); Jin-Keun Oh (Gwangyang-si, KR); Sang-Heon Kim (Gwangyang-si, KR); Yeol-Rae Cho (Pohang-si, KR)
Assignee: POSCO CO., LTD
C21D9/46B21D22/022C21D8/0226C21D8/0236C21D8/0263C21D8/0273C22C38/001C22C38/002C22C38/02C22C38/04C22C38/06C22C38/28C22C38/32C23C2/02C23C2/022C23C2/0224C25D3/22C25D3/44C21D2211/002C21D2211/005C21D2211/008C21D2211/009
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Quick Facts
Patent No.
US 12,516,394
App. No.
17/311,219
Granted
Jan 6, 2026
Kind
B2
Abstract

The present disclose relates to a plated steel sheet for hot press forming having excellent impact properties after hot press forming. The plated steel sheet includes: a base steel sheet containing, by weight, 0.15-0.4% of C, 0.1-1% of Si, 0.6-8% of Mn, 0.001-0.05% of P, 0.0001-0.02% of S, 0.01-0.1% of Al, 0.001-0.02% of N, 0.01-0.5% of Cr, and impurities; and a plating layer formed on the surface of the base steel sheet and composed of zinc, aluminum, or an alloy containing zinc and aluminum. The ratio (CS/CB) of a C content (CS) in a surface layer to a C content (CB) in the base steel sheet is 0.6 or less. The ratio ((MnS+CrS)/(MnB+CrB)) of the total content (MnS+CrS) of Mn and Cr in the surface layer to the total content (MnB+CrB) of Mn and Cr in the base steel sheet is 0.8 or more.

Claims (7)

1 . A plated steel sheet for hot press forming, the plated steel sheet comprising:

a base steel sheet including, by wt %, 0.15% to 0.4% of carbon (C), 0.1% to 1% of silicon (Si), 0.6% to 8% of manganese (Mn), 0.001% to 0.05% of phosphorus (P), 0.0001% to 0.02% of sulfur(S), 0.01% to 0.1% of aluminum (Al), 0.001% to 0.02% of nitrogen (N), 0.01% to 0.5% of chromium (Cr), a balance of Fe, and other impurities; and

a plating layer including zinc, aluminum, or alloys thereof on a surface of the base steel sheet,

wherein a ratio (Cs/CB) of a C content (Cs) of a surface layer portion to a C content (CB) of the base steel sheet is 0.6 or less, and a ratio ((Mns+Crs)/(MnB+CrB)) of a sum (Mns+Crs) of contents of Mn and Cr of the surface layer portion to a sum (MnB+CrB) of contents of Mn and Cr of the base steel sheet is 0.8 or more,

wherein the surface layer portion refers to a region to a depth of 15 μm from the surface of the base steel sheet excluding the plating layer.

2 . The plated steel sheet of claim 1 , wherein the base steel sheet further includes, by wt %, one or more of 0.0005% to 0.01% of boron (B) and 0.01% to 0.05% of titanium (Ti).

3 . The plated steel sheet of claim 1 , wherein a microstructure of the surface layer portion in the base steel sheet includes, by area fraction, 40% to 100% of ferrite and a balance of 0% to 60% of pearlite, bainite, or martensite, and a microstructure of a central portion in the base steel includes, by area fraction, 30% to 90% of ferrite and a balance of 10% to 70% of pearlite, bainite, or martensite.

Assignments (3)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Oct 26, 2022
From: POSCO HOLDINGS INC.
To: POSCO CO., LTD
Reel/Frame 061777/0937 →
CHANGE OF NAME Recorded Sep 28, 2022
From: POSCO
To: POSCO HOLDINGS INC.
Reel/Frame 061561/0730 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jun 7, 2021
From: KIM, SEONG-WOO; OH, JIN-KEUN; KIM, SANG-HEON; CHO, YEOL-RAE
To: POSCO
Reel/Frame 056494/0260 →
Priority Claims (1)
KR 10-2018-0164822 · Dec 19, 2018 · national
Continuity (1)
Related Publication 20220025479A1 · Jan 27, 2022
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