	US 12,123,071 B2
	High flangeable ultra-high strength ductile hot-rolled steel, method of manufacturing said hot-rolled steel and use thereof
Radhakanta Rana, Alkmaar (NL)
Assigned to TATA STEEL IJMUIDEN B.V., Velsen-Noord (NL)
Appl. No. 17/760,448
Filed by TATA STEEL IJMUIDEN B.V., Velsen-Noord (NL)
PCT Filed Feb. 11, 2021, PCT No. PCT/EP2021/053290 § 371(c)(1), (2) Date Aug. 9, 2022, PCT Pub. No. WO2021/160721, PCT Pub. Date Aug. 19, 2021.
Claims priority of application No. 20156728 (EP), filed on Feb. 11, 2020.
Prior Publication US 2023/0081354 A1, Mar. 16, 2023
Int. Cl. B32B 15/01 (2006.01); C21D 6/00 (2006.01); C21D 8/02 (2006.01); C21D 9/52 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/12 (2006.01)

CPC C21D 9/52 (2013.01) [B32B 15/012 (2013.01); B32B 15/013 (2013.01); C21D 6/005 (2013.01); C21D 6/008 (2013.01); C21D 8/0205 (2013.01); C21D 8/0226 (2013.01); C21D 8/0263 (2013.01); C22C 38/001 (2013.01); C22C 38/002 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/12 (2013.01); C21D 2211/008 (2013.01)]

20 Claims

1. A hot-rolled steel strip comprising (in wt. %):

C: 0.10-0.30;

Si 0.50-1.0;

Al 0.030-0.31;

Mn: 1.65-2.50;

(Si+Al): 0.80-1.31;

and optionally any one or more of alloying elements selected from:

V: less than 0.10;

Nb: less than 0.10;

Ti: less than 0.10;

Mo: less than 0.50;

Cr: less than 1.50;

Cu: less than 1.00;

Ni less than 0.50;

B: less than 0.0030 (30 ppm);

unavoidably also comprising:

N: less than 0.0100 (100 ppm);

S: less than 0.005;

P: less than 0.020;

the remainder being Fe and unavoidable impurities;

having a yield strength of at least 1100 MPa, an ultimate tensile strength of at least 1200 MPa, a yield ratio of at least 0.85, a total elongation of at least 6.0%, a hole expansion ratio of at least 30% and a bending angle at 1 mm thickness of at least 70°;

having a microstructure consisting of 60 to 85 vol. % of tempered martensite, 40 to 15 vol. % of fresh martensite, and less than 1 vol. % of retained austenite and no cementite or other carbides.