Abstract: A steel product or thin steel cast strip including, by weight, less than 0.25% carbon, between 0.20 and 2.0% manganese, between 0.05 and 0.50% silicon, less than 0.01% aluminum, and at least one of niobium between 0.01% and 0.20% and vanadium between 0.01% and 0.20%, and a microstructure of a majority bainite and acicular ferrite, and more than 70% niobium and/or vanadium in solid solution. The steel product may have an increase in elongation and an increase in yield strength after age hardening. The age hardened steel product may have niobium carbonitride particles with an average particle size of 10 nanometers and less, and may have substantially no niobium carbonitride particles greater than 50 nanometers. The steel product may have a yield strength of at least 380 MPa, a tensile strength of at least 410 MPa, or both. The product may have a total elongation of at least 6% or 10%.

Abstract: A hot rolled steel strip made by the steps including assembling a twin roll caster, forming a casting pool of molten steel of such composition that the cast strip produced comprises by weight, greater than 0.25% and up to 1.1% carbon, between 0.40 and 2.0% manganese, between 0.05 and 0.50% silicon, less than 0.01% aluminum, counter rotating the casting rolls to solidify metal shells and forming a steel strip, hot rolling the steel strip such that mechanical properties at 10% and 35% reduction are within 10% for yield strength, tensile strength and total elongation, and coiling the hot rolled steel strip at a temperature between 550 and 750° C. to provide a majority of the microstructure comprising pearlite, along with bainite and acicular ferrite. The steel may have a free oxygen content between 5 and 50 ppm or between 25 and 45 ppm.

Abstract: A steel product or thin steel cast strip comprised of, by weight, less than 0.25% carbon, between 0.20 and 2.0% manganese, between 0.05 and 0.50% silicon, less than 0.01% aluminum, and at least one of niobium between 0.01% and 0.20% and vanadium between 0.01% and 0.20%, and having a microstructure of a majority bainite and acicular ferrite, and more than 70% niobium and/or vanadium in solid solution. The steel product may have an increase in elongation and an increase in yield strength after age hardening. The age hardened steel product may have niobium carbonitride particles with an average particle size of 10 nanometers and less, and may have substantially no niobium carbonitride particles greater than 50 nanometers. The steel product may have a yield strength of at least 380 MPa or a tensile strength of at least 410 MPa, or both. The steel product or thin cast steel strip may have a total elongation of at least 6% or 10%.

Abstract: A method for making alloy strip by continuous casting with tensile strength of at least 900 MPa and total elongation of at least 30%, strip with tensile strength of at least 1200 MPa and total elongation of at least 20%, or strip with tensile strength of at least 1500 MPa and total elongation of at least 15%. Molten metal is introduced forming a casting pool supported on the casting rolls and counter-rotating the A heat flux is provided with a peak heat flux >20 Mw/m2. The strip is cooled at 1000-3000 K/sec. A roll biasing force >40 kN/meter of casting roll length is applied to form thin metal strip. The strip is then conveyed through a first enclosure with an atmosphere having an oxygen content of <5%. The cast strip is rolled through a rolling mill and reduced and modification of the microstructure is initiated.

Abstract: A steel product or thin steel cast strip including, by weight, less than 0.25% carbon, between 0.20 and 2.0% manganese, between 0.05 and 0.50% silicon, less than 0.01% aluminum, niobium between 0.01% and 0.20%, and vanadium between 0.01% and 0.20%. The steel product may have a tensile strength of between 550 and 600 MPa after age hardening at a peak temperature of between 700 and 750° C.

Abstract: A hot rolled steel strip made by the steps including assembling a twin roll caster, forming a casting pool of molten steel having a free oxygen content between 20 and 75 ppm and having a composition such that the cast strip comprises by weight, greater than 0.1 and not more than 0.5% carbon, between 0.9 and 2.0% manganese, between 0.05 and 0.50% silicon, greater than 0.01% and less than or equal to 0.15% phosphorus, and less than 0.01% aluminum, counter rotating the casting rolls forming the steel strip, hot rolling the strip such that mechanical properties at 10% and 35% reduction are within 10% for yield strength, tensile strength and total elongation, and coiling the strip at a temperature between 300 and 700° C. to provide a majority of the microstructure comprising bainite and acicular ferrite. Alternatively, the steel may have between 0.20 and 0.60% copper and manganese as low as 0.08%.

Abstract: A hot rolled steel strip made by the steps including assembling a twin roll caster, forming a casting pool of molten steel of such composition that the cast strip produced comprises by weight, greater than 0.25% and up to 1.1% carbon, between 0.40 and 2.0% manganese, between 0.05 and 0.50% silicon, less than 0.01% aluminum, counter rotating the casting rolls to solidify metal shells and forming a steel strip, hot rolling the steel strip such that mechanical properties at 10% and 35% reduction are within 10% for yield strength, tensile strength and total elongation, and coiling the hot rolled steel strip at a temperature between 550 and 750° C. to provide a majority of the microstructure comprising pearlite, along with bainite and acicular ferrite. The steel may have a free oxygen content between 5 and 50 ppm or between 25 and 45 ppm.

Abstract: A hot rolled steel strip made by the steps including assembling a twin roll caster, forming a casting pool of molten steel of such composition that the cast strip produced comprises by weight, greater than 0.25% and up to 1.1% carbon, between 0.40 and 2.0% manganese, between 0.05 and 0.50% silicon, less than 0.01% aluminum, counter rotating the casting rolls to solidify metal shells and forming a steel strip, hot rolling the steel strip such that mechanical properties at 10% and 35% reduction are within 10% for yield strength, tensile strength and total elongation, and coiling the hot rolled steel strip at a temperature between 550 and 750° C. to provide a majority of the microstructure comprising pearlite, along with bainite and acicular ferrite. The steel may have a free oxygen content between 5 and 50 ppm or between 25 and 45 ppm.

Abstract: A hot rolled steel strip made by the steps including assembling a twin roll caster, forming a casting pool of molten steel having a free oxygen content between 20 and 75 ppm and having a composition such that the cast strip comprises by weight, less than 0.25% carbon, between 0.9 and 2.0% manganese, between 0.05 and 0.50% silicon, greater than 0.01% and less than or equal to 0.15% phosphorus, and less than 0.01% aluminum, counter rotating the casting rolls forming the steel strip, hot rolling the strip such that mechanical properties at 10% and 35% reduction are within 10% for yield strength, tensile strength and total elongation, and coiling the strip at a temperature between 300 and 700° C. to provide a majority of the microstructure comprising bainite and acicular ferrite. Alternatively, the steel may have between 0.20 and 0.60% copper and manganese as low as 0.08%.

Abstract: A hot rolled steel strip made by the steps including assembling a twin roll caster, forming a casting pool of molten steel of such composition that the cast strip produced comprises by weight, greater than 0.25% and up to 1.1% carbon, between 0.40 and 2.0% manganese, between 0.05 and 0.50% silicon, less than 0.01% aluminum, counter rotating the casting rolls to solidify metal shells and forming a steel strip, hot rolling the steel strip such that mechanical properties at 10% and 35% reduction are within 10% for yield strength, tensile strength and total elongation, and coiling the hot rolled steel strip at a temperature between 550 and 750° C. to provide a majority of the microstructure comprising pearlite, along with bainite and acicular ferrite. The steel may have a free oxygen content between 5 and 50 ppm or between 25 and 45 ppm.

Abstract: A steel product or thin steel cast strip including, by weight, less than 0.25% carbon, between 0.20 and 2.0% manganese, between 0.05 and 0.50% silicon, less than 0.01% aluminum, and at least one of niobium between 0.01% and 0.20% and vanadium between 0.01% and 0.20%, and a microstructure of a majority bainite and acicular ferrite, and more than 70% niobium and/or vanadium in solid solution. The steel product may have an increase in elongation and an increase in yield strength after age hardening. The age hardened steel product may have niobium carbonitride particles with an average particle size of 10 nanometers and less, and may have substantially no niobium carbonitride particles greater than 50 nanometers. The steel product may have a yield strength of at least 380 MPa, a tensile strength of at least 410 MPa, or both. The product may have a total elongation of at least 6% or 10%.

Abstract: A steel product or thin steel cast strip comprised of, by weight, less than 0.25% carbon, between 0.20 and 2.0% manganese, between 0.05 and 0.50% silicon, less than 0.01% aluminum, and at least one of niobium between 0.01% and 0.20% and vanadium between 0.01% and 0.20%, and having a microstructure of a majority bainite and acicular ferrite, and more than 70% niobium and/or vanadium in solid solution. The steel product may have an increase in elongation and an increase in yield strength after age hardening. The age hardened steel product may have niobium carbonitride particles with an average particle size of 10 nanometers and less, and may have substantially no niobium carbonitride particles greater than 50 nanometers. The steel product may have a yield strength of at least 380 MPa or a tensile strength of at least 410 MPa, or both. The steel product or thin cast steel strip may have a total elongation of at least 6% or 10%.

Abstract: A composition and method of making a high-strength low-alloy hot-rolled steel sheet, strip, or plate bearing titanium as the principal or only microalloy strengthening element. The steel is substantially ferritic and has a microstructure that is at least 20% acicular ferrite. The steel has a minimum yield strength of at least 345 MPa (50 ksi) and even over 621 MPa (90 ksi) adding titanium as the lone microalloy element for strengthening, with elongation of 15% and more. Addition of vanadium, niobium, or a combination thereof can result in yield strengths exceeding 621 MPa (90 ksi). Effective titanium content, being the content of titanium in the steel not in the form of nitrides, oxides, or sulfides, is in the range of 0.01 to 0.12% by weight. The manufacturing process includes continuously casting a thin slab and reducing the slab thickness using thermomechanical controlled processing, including dynamic recrystallization controlled rolling.