US 11,788,166 B2
Cold-rolled steel plate for hot forming, having excellent corrosion-resistance and spot-weldability, hot-formed member, and method for manufacturing same
Jin-Keun Oh, Gwangyang-si (KR); Yeol-Rae Cho, Gwangyang-si (KR); A-Ra Cho, Incheon (KR); Jin-Ho Cha, Gwangyang-si (KR); Si-Myoung Heo, Gwangyang-si (KR); Jeong-Won Seo, Gwangyang-si (KR); and Seong-Woo Kim, Gwangyang-si (KR)
Assigned to POSCO CO., LTD, Pohang-si (KR)
Filed by POSCO Co., Ltd, Pohang-si (KR)
Filed on Feb. 27, 2023, as Appl. No. 18/114,387.
Application 18/114,387 is a division of application No. 17/885,860, filed on Aug. 11, 2022, granted, now 11,624,100.
Application 17/885,860 is a continuation of application No. 16/336,645, granted, now 11,441,205, issued on Sep. 13, 2022, previously published as PCT/KR2017/010639, filed on Sep. 26, 2017.
Claims priority of application No. 10-2016-0123273 (KR), filed on Sep. 26, 2016.
Prior Publication US 2023/0235423 A1, Jul. 27, 2023
Int. Cl. C21D 9/46 (2006.01); B21B 3/02 (2006.01); B21D 22/02 (2006.01); C21D 6/00 (2006.01); C21D 8/02 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/20 (2006.01); C22C 38/22 (2006.01); C22C 38/24 (2006.01); C22C 38/26 (2006.01); C22C 38/50 (2006.01); C22C 38/54 (2006.01)
CPC C21D 9/46 (2013.01) [B21B 3/02 (2013.01); B21D 22/022 (2013.01); C21D 6/004 (2013.01); C21D 6/005 (2013.01); C21D 6/008 (2013.01); C21D 8/0205 (2013.01); C21D 8/0226 (2013.01); C21D 8/0236 (2013.01); C21D 8/0247 (2013.01); C22C 38/001 (2013.01); C22C 38/002 (2013.01); C22C 38/008 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/20 (2013.01); C22C 38/22 (2013.01); C22C 38/24 (2013.01); C22C 38/26 (2013.01); C22C 38/50 (2013.01); C22C 38/54 (2013.01); C21D 2211/003 (2013.01); C21D 2211/005 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A hot-formed member, comprising:
a base member comprising C: 0.1 to 0.4%, Si: 0.5 to 2.0%, Mn: 0.01 to 4.0%, Al: 0.001 to 0.4%, P: 0.001 to 0.05%, S: 0.0001 to 0.02%, Cr: 0.5% or higher and less than 3.0%, N: 0.001 to 0.02%, and a balance of Fe and inevitable impurities by weight %,
wherein the base member satisfies equation (1) below:
1.4≤0.4*Cr+Si≤3.2  equation (1):
where each element symbol is a value of a content of each element measured by weight %; and
wherein an Si-based amorphous oxide layer having a thickness of 2 nm to 2000 nm is continuously or discontinuously formed on a surface of the base member.