US 6,743,307 B1 · High resistance steel band or sheet and method for the production thereof

Abstract

The invention relates to a higher-strength steel strip or steel sheet comprising a predominantly ferritic-martensitic microstructure with a martensite content of between 4 and 20%, wherein the steel strip or steel sheet, apart from Fe and impurities due to smelting, comprises (in % by weight) 0.05-0.2% C, ≦1.0% Si, 0.8-2.0% Mn, ≦0.1% P, ≦0.015% S, 0.02-0.4% Al, ≦0.005% N, 0.25-1.0% Cr, 0.002-0.01% B. Preferably the martensite content is approximately 5% to 20% of the predominantly martensitic-ferritic microstructure. Such a higher-strength steel strip or steel sheet made from a dual phase steel comprises good mechanical/technological properties even after being subjected to an annealing process which includes an overageing treatment. Furthermore, the invention relates to a method for producing steel strip or steel sheet according to the invention.

Claims12

Dependent claims

A higher strength steel strip or steel sheet comprising a predominantly ferritic-martensitic microstructure with a martensite content of between 40% and 20%, wherein the steel strip or steel sheet, apart from Fe and impurities due to smelting, comprises (in % by weight)

C:
0.05-0.2%;
Si:
≦1.0;
Mn:
0.8-2.0% P:
≦0.1%;
S:
≦0.015%;
Al 0.02-0.4%;
N:
≦0.005%;
Cr:
0.25-1.0%;
B:
0.002-0.01%;
and
optionally Ti:
wherein for A1 contents of 0.02-0.06%, the Ti content is at least 2.8×AN, with AN=content of N;
and wherein the A1 content is 0.1-0.4% if there is no Ti present.

17 more elements

Dependencies are inferred from the claim text.

High resistance steel band or sheet and method for the production thereof

Life of this patent

High resistance steel band or sheet and method for the production thereof

Life of this patent

Abstract

Claims12