	US 12,319,992 B2
	Cold rolled steel sheet
Florian Winkelhofer, Kirchberg-Thening (AT); Thomas Hebesberger, Pasching (AT); Martin Gruber, Pregarten (AT); and Johannes Rehrl, St. Marien (AT)
Assigned to VOESTALPINE STAHL GMBH, Linz (AT)
Appl. No. 17/423,742
Filed by VOESTALPINE STAHL GMBH, Linz (AT)
PCT Filed Nov. 28, 2019, PCT No. PCT/EP2019/082855 § 371(c)(1), (2) Date Jul. 16, 2021, PCT Pub. No. WO2020/151855, PCT Pub. Date Jul. 30, 2020.
Claims priority of application No. 1950072-7 (SE), filed on Jan. 22, 2019.
Prior Publication US 2022/0112586 A1, Apr. 14, 2022
Int. Cl. C22C 38/58 (2006.01); C21D 8/02 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/06 (2006.01); C22C 38/42 (2006.01); C22C 38/46 (2006.01); C22C 38/48 (2006.01); C22C 38/50 (2006.01); C22C 38/54 (2006.01)

CPC C22C 38/58 (2013.01) [C21D 8/0205 (2013.01); C21D 8/0236 (2013.01); C22C 38/002 (2013.01); C22C 38/008 (2013.01); C22C 38/02 (2013.01); C22C 38/06 (2013.01); C22C 38/42 (2013.01); C22C 38/46 (2013.01); C22C 38/48 (2013.01); C22C 38/50 (2013.01); C22C 38/54 (2013.01); C21D 2211/001 (2013.01); C21D 2211/002 (2013.01); C21D 2211/005 (2013.01); C21D 2211/008 (2013.01)]

7 Claims

1. A cold rolled steel sheet having:

a) a composition consisting of, in wt. %:


	C	0.15-0.25
	Si	1.5-1.6
	Mn	2.2-2.8
	Cr	≤0.8
	Mo	≤0.2
	Al	0.03-1.0
	Nb	≤0.04
	V	≤0.04
	Ti	0.02-0.04
	B	0.001-0.005
	Ti/B	8-11

balance Fe apart from impurities,

wherein the impurity contents of Cu and Ni are limited to


	Cu	≤0.15
	Ni	≤0.15;

b) a multiphase microstructure comprising a matrix of bainitic ferrite and wherein the amount of polygonal ferrite is ≤10 vol. %, and

c) the following mechanical properties


	a tensile strength (R_m)	980-1500 MPa
	yield strength (R_p0.2)	580-1200 MPa
	total elongation (A₅₀)	≥3%.