United States Steel Corporation
HIGH DUCTILITY ZINC-COATED STEEL SHEET PRODUCTS

Abstract:

High ductility steel sheet products are disclosed that have controlled compositions that, in combination with controlled heating cycles, produce desirable microstructures and favorable mechanical properties including ultimate tensile strength of at least 1180 MPa, high ductility, hole expansion, bendability and formability. Steel compositions include controlled amounts of carbon, manganese, silicon, chromium, molybdenum and aluminum. Rolled sheets are subjected to a thermal cycle including a heating stage followed by quenching to below the martensite-start temperature and aging.