US 12,344,923 B2
Zinc plated steel sheet having excellent spot weldability and manufacturing method thereof
Ki-Cheol Kang, Gwangyang-si (KR); Sea-Woong Lee, Gwangyang-si (KR); Kyoo-Young Lee, Gwangyang-si (KR); Jong-Ho Kim, Gwangyang-si (KR); and Young-Roc Im, Gwangyang-si (KR)
Assigned to POSCO CO., LTD, Pohang-si (KR)
Appl. No. 17/415,543
Filed by POSCO, Pohang-si (KR)
PCT Filed Dec. 18, 2019, PCT No. PCT/KR2019/017929
§ 371(c)(1), (2) Date Jun. 17, 2021,
PCT Pub. No. WO2020/130602, PCT Pub. Date Jun. 25, 2020.
Claims priority of application No. 10-2018-0165177 (KR), filed on Dec. 19, 2018.
Prior Publication US 2022/0056564 A1, Feb. 24, 2022
Int. Cl. C22C 38/38 (2006.01); C21D 8/02 (2006.01); C21D 9/46 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/06 (2006.01); C22C 38/22 (2006.01); C22C 38/26 (2006.01); C22C 38/28 (2006.01); C22C 38/32 (2006.01); C23C 2/02 (2006.01); C23C 2/06 (2006.01); C23C 2/28 (2006.01); C23C 2/40 (2006.01)
CPC C22C 38/38 (2013.01) [C21D 8/0205 (2013.01); C21D 8/0226 (2013.01); C21D 8/0236 (2013.01); C21D 9/46 (2013.01); C22C 38/001 (2013.01); C22C 38/002 (2013.01); C22C 38/02 (2013.01); C22C 38/06 (2013.01); C22C 38/22 (2013.01); C22C 38/26 (2013.01); C22C 38/28 (2013.01); C22C 38/32 (2013.01); C23C 2/02 (2013.01); C23C 2/0222 (2022.08); C23C 2/0224 (2022.08); C23C 2/024 (2022.08); C23C 2/06 (2013.01); C23C 2/28 (2013.01); C23C 2/40 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A zinc plated steel sheet having excellent spot weldability, comprising:
a steel sheet; and
a zinc-based plated layer formed on a surface of the steel sheet,
wherein a ratio (a/b) between a widthwise average value (a) of thickness of an internal oxidized layer and a widthwise standard deviation (b) of thickness of the internal oxidized layer in the steel sheet is 1.5 or more, and
wherein the widthwise average value (a) of the thickness of an internal oxidized layer and the widthwise standard deviation (b) of thickness of the internal oxidized layer are obtained by dividing the overall width of the steel sheet at equal intervals, measuring the thickness of the internal oxidized layer at each divided point, and calculating the average and standard deviation of these values.