	US 11,884,989 B2
	Hot-stamping formed body
Daisuke Maeda, Tokyo (JP); Yuri Toda, Tokyo (JP); Tomohito Tanaka, Tokyo (JP); and Kazuo Hikida, Tokyo (JP)
Assigned to NIPPON STEEL CORPORATION, Tokyo (JP)
Appl. No. 17/599,935
Filed by NIPPON STEEL CORPORATION, Tokyo (JP)
PCT Filed May 13, 2020, PCT No. PCT/JP2020/019129 § 371(c)(1), (2) Date Sep. 29, 2021, PCT Pub. No. WO2020/241260, PCT Pub. Date Dec. 3, 2020.
Claims priority of application No. 2019-101985 (JP), filed on May 31, 2019.
Prior Publication US 2022/0195557 A1, Jun. 23, 2022
Int. Cl. B32B 15/01 (2006.01); C21D 9/48 (2006.01); C21D 1/18 (2006.01); C21D 6/00 (2006.01); C21D 8/04 (2006.01); C22C 18/00 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/06 (2006.01); C22C 38/26 (2006.01); C22C 38/28 (2006.01); C22C 38/32 (2006.01); C22C 38/38 (2006.01)

CPC C21D 9/48 (2013.01) [B32B 15/013 (2013.01); C21D 1/18 (2013.01); C21D 6/002 (2013.01); C21D 6/005 (2013.01); C21D 6/008 (2013.01); C21D 8/0405 (2013.01); C21D 8/0426 (2013.01); C21D 8/0436 (2013.01); C21D 8/0463 (2013.01); C22C 18/00 (2013.01); C22C 38/001 (2013.01); C22C 38/002 (2013.01); C22C 38/005 (2013.01); C22C 38/02 (2013.01); C22C 38/06 (2013.01); C22C 38/26 (2013.01); C22C 38/28 (2013.01); C22C 38/32 (2013.01); C22C 38/38 (2013.01); C21D 2211/001 (2013.01); C21D 2211/008 (2013.01)]

3 Claims

1. A hot-stamping formed body comprising:

a base steel sheet consisting of, as a chemical composition, by mass %,

C: 0.15% or more and less than 0.70%,

Si: 0.005% to 0.250%,

Mn: 0.30% to 3.00%,

sol. Al: 0.0002% to 0.500%,

P: 0.100% or less,

S: 0.1000% or less,

N: 0.0100% or less,

Nb: 0% to 0.150%,

Ti: 0% to 0.150%,

Mo: 0% to 1.000%,

Cr: 0% to 1.000%,

B: 0% to 0.0100%,

Ca: 0% to 0.010%,

REM: 0% to 0.30%, and

a remainder consisting of Fe and impurities; and

a plating layer provided on a surface of the base steel sheet, the plating layer having an adhesion amount of 10 g/m²to 90 g/m²and a composition consisting of Ni having a Ni content of 10 mass % to 25 mass % with a remainder of Zn and impurities,

wherein, in a surface layer region, which is a region from the surface of the base steel sheet to a position at a depth of 50 μm from the surface, an average grain size of prior austenite grains is 10.0 μm or less, and a Ni concentration per unit area at grain boundaries having an average crystal orientation difference of 15° or more is 1.5 mass %/μm²or more, and

fracture is absent in a case a test piece to which a V notch is applied is subjected to 900 MPa in terms of a nominal stress calculated by dividing a load applied to the test piece by a cross-sectional area of a bottom of the V notch and immersed in an aqueous solution obtained by dissolving 3 g/l of ammonium thiocyanate in 3% saline solution at room temperature for 12 hours.