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

Claim 0:
1. A hot rolled, complex metallographic structured steel sheet comprising:
(a) a composition comprising the following elements by weight:
carbon in a range from 0.02% 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; and
a multi-phase microstructure only after hot rolling having in combination: bainite between 15% and 45% by volume, martensite+austenite (M+A) constituent between 5% and 35% by volume, tempered and non-tempered martensite at less than 15% by volume, a remainder volume essentially ferrite; the remainder volume comprising a mixture of polygonal ferrite (PF) and quasi-polygonal ferrite is present in a range of 30-60% by volume of the microstructure.