US 11,654,653 B2
Method for the manufacturing of liquid metal embrittlement resistant galvannealed steel sheet
Christian Allely, Metz (FR); Pascal Bertho, Yutz (FR); Anirban Chakraborty, Chesterton, IN (US); and Hassan Ghassemi-Armaki, Schererville, IN (US)
Assigned to ArcelorMittal, Luxembourg (LU)
Appl. No. 16/605,473
Filed by ArcelorMittal, Luxembourg (LU)
PCT Filed Apr. 25, 2018, PCT No. PCT/IB2018/000429
§ 371(c)(1), (2) Date Oct. 15, 2019,
PCT Pub. No. WO2018/203126, PCT Pub. Date Nov. 8, 2018.
Claims priority of application No. PCT/IB2017/000520 (WO), filed on May 5, 2017.
Prior Publication US 2020/0123674 A1, Apr. 23, 2020
Int. Cl. C25D 5/12 (2006.01); B23K 11/11 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C25D 5/50 (2006.01); C21D 8/02 (2006.01); C23C 10/28 (2006.01); C25D 3/12 (2006.01); C21D 9/46 (2006.01); C25D 3/22 (2006.01); C22C 38/06 (2006.01); B32B 15/01 (2006.01)
CPC B32B 15/011 (2013.01) [B23K 11/11 (2013.01); C21D 8/0273 (2013.01); C21D 9/46 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C23C 10/28 (2013.01); C25D 3/12 (2013.01); C25D 3/22 (2013.01); C25D 5/12 (2013.01); C25D 5/50 (2013.01)] 13 Claims
 
1. A method for the manufacture of a galvannealed steel sheet comprising the following successive steps:
A) coating a steel sheet with a first coating consisting of nickel and having a thickness between 200 nm and 500 nm, said steel sheet having a composition including in weight percentage:
0.10<C<0.40%,
1.5<Mn<3.0%,
0.7<Si<3.0%,
0≤Nb≤0.5%,
0≤B≤0.010%,
0≤Cr≤1.0%,
0≤Mo≤0.50%,
0≤Ni≤1.0%,
0≤Ti≤0.5%,
a remainder of the composition being iron and inevitable impurities resulting from the processing;
B) annealing the coated steel sheet at a temperature between 600 to 1200° C. in an atmosphere comprising from 1 to 10% of H2 at a dew point between −60 and −30° C.;
C) coating the steel sheet obtained in step B) with a second coating based on zinc; and
D) subjecting the steel sheet obtained in step C) to an alloying heat treatment to form a galvannealed steel sheet.