Ultra-high strength weathering steel and high friction rolling of the same
AssigneeNucor Corporation
InventorsTao Wang, Kishlay Mishra
Life of this patent
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Abstract
Disclosed herein is a light-gauge, ultra-high strength weathering steel sheet comprising between 0.5% and 1.5% nickel. Also disclosed herein is a high friction rolled carbon alloy steel strip free of prior austenite grain boundary depressions and having a smear pattern. Still further disclosed herein is a high friction rolled carbon alloy steel strip that has been surface homogenized to provide a thin cast steel strip free of a smear pattern.
Claims15
A continuously cast hot rolled ultra-high strength weathering thin cast steel strip comprising:
- an as cast thickness cast at less than or equal to 2.5 mm;
- a composition comprising:
- by weight, between 0.20% and 0.40% carbon, less than 1.0% chromium, between 0.7% and 2.0% manganese, between 0.10% and 0.50% silicon, between 0.1% and 1.0% copper, less than or equal to 0.12% niobium, less than 0.5% molybdenum, between 0.5% and 1.5% nickel, and silicon killed containing less than 0.01% aluminum, and the remainder iron and impurities resulting from melting;
- a corrosion index of 6.0 or greater;
- a microstructure having, by volume, at least 75% martensite formed from prior austenite grain sizes of at least 100 μm, a yield strength of between 700 and 1600 MPa, a tensile strength of between 1000 and 2100 MPa, and an elongation of between 1% and 10%;
- and
- a pair of hot rolled opposing surfaces wherein less than 50% of the pair of opposing surfaces contain prior austenite grain boundaries.
A continuously cast hot rolled ultra-high strength weathering thin cast steel strip comprising:
- an as cast thickness cast at less than or equal to 2.5 mm;
- a composition comprising:
- by weight, between 0.20% and 0.40% carbon, less than 1.0% chromium, between 0.7% and 2.0% manganese, between 0.10% and 0.50% silicon, between 0.1% and 1.0% copper, less than or equal to 0.12% niobium, less than 0.5% molybdenum, between 0.5% and 1.5% nickel, and silicon killed containing less than 0.01% aluminum, and the remainder iron and impurities resulting from melting;
- a corrosion index of 6.0 or greater;
- a microstructure having, by volume, at least 75% martensite formed from prior austenite grain sizes of at least 100 μm, a yield strength of between 700 and 1600 MPa, a tensile strength of between 1000 and 2100 MPa, and an elongation of between 1% and 10%;
- and
- a pair of hot rolled opposing surfaces wherein 10% or less of the pair of opposing surfaces contain prior austenite grain boundary depressions.
A continuously cast hot rolled ultra-high strength weathering thin cast steel strip comprising:
- an as cast thickness cast at less than or equal to 2.5 mm;
- a composition comprising:
- by weight, between 0.20% and 0.40% carbon, less than 1.0% chromium, between 0.7% and 2.0% manganese, between 0.10% and 0.50% silicon, between 0.1% and 1.0% copper, less than or equal to 0.12% niobium, less than 0.5% molybdenum, between 0.5% and 1.5% nickel, and silicon killed containing less than 0.01% aluminum, and the remainder iron and impurities resulting from melting;
- a corrosion index of 6.0 or greater;
- a microstructure having, by volume, at least 75% martensite formed from prior austenite grain sizes of at least 100 μm, a yield strength of between 700 and 1600 MPa, a tensile strength of between 1000 and 2100 MPa, and an elongation of between 1% and 10%;
- and
- a pair of hot rolled opposing surfaces having a smear pattern and free of prior austenite grain boundary depressions.
Dependencies are inferred from the claim text.