Patent ID: 11965230
Assignee: NUCOR CORPORATION
Field: Materials, metallurgy (Chemistry)
Classification: CPC C | IPC C

Claim 12:
13. A hot rolled, complex metallographic structured steel sheet having a composition comprising the following elements by weight:
carbon in a range from 0.01% to 0.2%,
manganese in a range from 1.0% to 3.5%,
phosphorous less than or equal to 0.1%,
silicon less than or equal to 1.2%,
aluminum in a range from 0.01% to less than 0.10%,
nitrogen less than or equal to 0.02%,
copper less than or equal to 0.5%,
vanadium less than or equal to 0.12%,
the composition having no purposeful addition of boron,
and the balance of the composition comprising iron and incidental ingredients;, wherein only after hot rolling the hot rolled sheet has a uniform multiphase microstructure of:
bainite between 15% and 45% by volume;
martensite+austenite (M+A) constituent between 10% and 30% by volume;
tempered and non-tempered martensite present at less than 15% by volume; and
a remainder volume of a mixture of polygonal ferrite (PF) and quasi-polygonal ferrite,
the remainder volume present in a range of 30-60% by volume.