US 2026/0286484 A1 · Steel sheet and high strength press hardened steel part and method of manufacturing the same

Abstract

A steel sheet made of a steel having a composition including, C: 0.3-0.4%, Mn: 0.5-1.0%, Si: 0.4-0.8%, Cr: 0.1-1.0%, Mo: 0.1-0.5%, Nb: 0.01-0.1%, Al: 0.01-0.1%, Ti: 0.008-0.03%, B: 0.0005-0.003%, P ≤0.020%, Ca ≤0.001%, S ≤0.004%, N ≤0.005% and including optionally Ni <0.5%, having a microstructure including, in surface fraction, from 60% to 95% of ferrite, the rest being martensite-austenite islands, pearlite or bainite, and including a bulk and a skin layer occupying the outermost 10% of the thickness on either sides of the bulk, the skin layer having a skin layer inclusion population wherein the cumulated surface fraction of oxides, MnS and TiNbCN is equal to or below 75*10−6.

Claims14

Dependent claims

A steel sheet made of a steel having a composition comprising, by weight percent:

C
:
0.3
-
0.4
%
Mn
:
0.5
-
1.
%
Nb
:
0.01
-
0.1
%
Ti
:
0.008
-
0.03
%
S
≤
0.004
%
a remainder of the composition being iron and unavoidable impurities resulting from processing,
the steel sheet having a microstructure comprising, in surface fraction, from 60% to 96% of ferrite, the rest being martensite-austenite islands, pearlite or bainite,
the steel sheet comprising from a bulk to the surface of the coated steel sheet:
the bulk, the bulk being topped by a skin layer occupying the outermost 10% of the thickness on either side of the bulk, the skin layer having a skin layer inclusion population wherein the cumulated surface fraction of oxides, MnS and TiNbCN is equal to or less than 75*10−6.

29 more elements

Dependencies are inferred from the claim text.

Steel sheet and high strength press hardened steel part and method of manufacturing the same

Life of this patent

Steel sheet and high strength press hardened steel part and method of manufacturing the same

Life of this patent

Abstract

Claims14