Patent ID: 11920207
Assignee: ARCELORMITTAL
Field: Materials, metallurgy (Chemistry)
Classification: CPC C  B | IPC B  C

Claim 0:
1. A cold rolled heat treated steel sheet having a composition comprising the following elements, expressed in percentage by weight:
0.1%≤Carbon≤0.5%
1%≤Manganese≤3.4%
0.5%≤Silicon≤2.5%
0.03%≤Aluminum≤1.5%
0%≤Sulfur≤0.003%,
0.002%≤Phosphorus≤0.02%
0%≤Nitrogen≤0.01%
and optionally containing one or more of the following elements
0.05%≤Chromium≤1%
0.001%≤Molybdenum≤0.5%
0.001%≤Niobium≤0.1%
0.001%≤Titanium≤0.1%
0.01%≤Copper≤2%
0.01%≤Nickel≤3%
0.0001%≤Calcium≤0.005%
0%≤Vanadium≤0.1%
0%≤Boron≤0.003%
0%≤Cerium≤0.1%
0%≤Magnesium≤0.010%
0%≤Zirconium≤0.010%
a remainder being iron and unavoidable impurities caused by processing;
a microstructure of the cold rolled heat treated steel sheet comprising in area fraction, 10 to 30% Residual Austenite, 50 to 85% Bainite, 1 to 20% Quenched Martensite, and less than 30% Tempered Martensite, the Bainite consisting of Lath Bainite and Granular Bainite.