Abstract: A twin roll casting system includes a pair of counter-rotating casting rolls, a casting roll controller is configured to adjust at least one process control setpoint for the casting rolls in response to control signals. A cast strip sensor measures at least one parameter of the cast strip. A controller receives measurement signals from the cast strip sensor provides control signals to the casting roll controller. The controller is a data-driven model comprising a database of state-input pairs; and executes the following steps at each time step: measure a state-input similarity between a new state observation and samples, assign a weight to each consequent output of samples based on the similarity measured, and sum the weighted outputs and predict an output of a new state observation. The controller is configured to provide the control signals to the casting roll controller based on the predicted output of the new state observation.

Abstract: A method of and apparatus for continuous casting of thin cast strip including removing oxides from the casting surface of each casting roll by contacting the casting surface of each casting roll with a rotating brush between the nip and the casting area, determining the temperature in segments along the casting roll surfaces or across the cast strip adjacent the nip, and delivering gas adjacent the casting surface between the rotating cleaning brush and the casting area regulated in segments corresponding to the determined temperature in the segment to control the quality of the strip produced. The gas delivery adjacent the casting surface between the rotating brush and the casting area may be done in at least five segments along the casting roll, and the temperature determination step may be done in a continuum such as by a scanning pyrometer. The temperature determination of the cast strip may be done between 0.2 and 1 meter from the nip.

Abstract: A method of controlling heat flux between the casting pool and the surfaces of the casting roll in a strip steel casting process includes controlling the concentration of nitrogen in the steel melt. The concentration of nitrogen may be controlled to achieve an operational heat transfer to the casting roll. The beat flux to the casting rolls may be controlled by maintaining the sum of partial pressures calculated from the nitrogen and hydrogen concentrations in the casting pool below 1.15 atmospheres. Decreasing the concentration of nitrogen can increase heat flux at the casting rolls.

Abstract: A method of producing cast steel strip having low surface roughness and low porosity by casting with molten steel having a total oxygen content of at least about 100 ppm and a temperature that allows a majority of any oxide inclusions to be in a liquidus state. The steel strip produced by the method may have a per unit area density of at least about 120 oxide inclusions per square millimeter to a depth of about 2 microns from the strip surface.

Abstract: A method of and apparatus for continuous casting of thin cast strip including removing oxides from the casting surface of each casting roll by contacting the casting surface of each casting roll with a rotating brush between the nip and the casting area, determining the temperature in segments along the casting roll surfaces or across the cast strip adjacent the nip, and delivering gas adjacent the casting surface between the rotating cleaning brush and the casting area regulated in segments corresponding to the determined temperature in the segment to control the quality of the strip produced. The gas delivery adjacent the casting surface between the rotating brush and the casting area may be done in at least five segments along the casting roll, and the temperature determination step may be done in a continuum such as by a scanning pyrometer. The temperature determination of the cast strip may be done between 0.2 and 1 meter from the nip.

Abstract: A method of producing cast steel strip having low surface roughness and low porosity by casting with molten steel having a total oxygen content of at least about 70 ppm and a free oxygen content between 20 and 60 ppm, and a temperature that allows a majority of any oxide inclusions to be in a liquidus state. The total oxygen content may be at least 100 ppm and the free oxygen content between 30 and 50 ppm. The steel strip produced by the method may have a per unit area density of at least about 120 oxide inclusions per square millimeter to a depth of about 2 microns from the strip surface.

Abstract: A method of and apparatus for localized control of heat flux in continuous casting of thin cast strip comprising removing oxides from the casting surface of each casting roll by contacting the casting surface of each casting roll with the rotating brush in advance of the casting area, and delivering gas at the casting surface between the rotating brush and entry to the casting area to form a gas layer on the casting surface of each casting roll where the oxides have been removed. The delivering of gas at the casting surface between the rotating brush and entry to the casting area is preferably done in at least three zones along the casting roll axes to form a gas layer on the casting surface of each casting roll where the oxides have been removed, where the gas projected in the respective zones can be of different composition, mixture, pressure, or combination thereof.

Abstract: A thin steel strip with low surface roughness and low porosity produced by casting with molten steel having a total oxygen content of at least about 100 ppm and a temperature that allows a majority of any oxide inclusions to be in a liquidus state. The steel strip produced by the method may have a per unit area density of at least about 120 oxide inclusions per square millimeter to a depth of about 2 microns from the strip surface.

Abstract: A thin cast strip is formed having at least one microstructure selected from the group consisting of polygonal ferrite, acicular ferrite, Widmanstatten, bainite and martinsite, a surface roughness of less than 1.5 microns Ra and a scale thickness of less than about 10 microns by applying a mixture of water and oil on the work rolls of the hot rolling mill, passing the thin cast strip at a temperature of less than 1100° C. through the hot rolling mill while the mixture of oil and water is applied to the work rolls, and shrouding the thin cast strip from the casting rolls through the hot rolling mill in an atmosphere of less than 5% oxygen to form the thin cast strip.

Abstract: A method of controlling heat flux between the casting pool and the surfaces of the casting roll in a strip steel casting process includes controlling the concentration of nitrogen in the steel melt. The concentration of nitrogen may be controlled to achieve an operational heat transfer to the casting roll. The beat flux to the casting rolls may be controlled by maintaining the sum of partial pressures calculated from the nitrogen and hydrogen concentrations in the casting pool below 1.15 atmospheres. Decreasing the concentration of nitrogen can increase heat flux at the casting rolls.

Abstract: A system for determining process parameters for the ladle refinement of steel includes a computer executing a number of software algorithms for determining one or more process parameters for various steel refinement process steps. In one embodiment, for example, the computer is configured to determine the total amount of flux additions to achieve a desired sulfur percentage as part of a steel desulfurization process. In another embodiment, the computer is configured to determine the total quantity of oxygen to be injected into the steel as part of a steel reoxidation process. In still another embodiment, the computer is configured to determine a melting temperature of inclusions within the refined steel, and to determine whether this melting temperature is within an acceptable range to successfully process the steel in a continuous steel strip casting apparatus/process, or whether the steel must be reworked to achieve an acceptable inclusion melting temperature.

Abstract: A system and method for producing thin cast strip by continuous casting is disclosed. The system includes a twin-roll casting apparatus having a pair of casting rolls positioned laterally adjacent each other to form a nip between the casting rolls through which metal strip may be continuously cast. A drive mechanism of the system is capable of individually driving the rotational speed of the casting rolls in a counter-rotational direction to cause the strip to pass through the nip between the casting rolls. A control mechanism of the system is capable of varying an alignment angle between the casting rolls to reduce effects of eccentricity in the casting rolls on a profile of the strip produced by the casting rolls.

Abstract: A method of and apparatus for localized control of heat flux in continuous casting of thin cast strip comprising removing oxides from the casting surface of each casting roll by contacting the casting surface of each casting roll with the rotating brush in advance of the casting area, and delivering gas at the casting surface between the rotating brush and entry to the casting area to form a gas layer on the casting surface of each casting roll where the oxides have been removed. The delivering of gas at the casting surface between the rotating brush and entry to the casting area is preferably done in at least three zones along the casting roll axes to form a gas layer on the casting surface of each casting roll where the oxides have been removed, where the gas projected in the respective zones can be of different composition, mixture, pressure, or combination thereof.

Abstract: A cast carbon steel strip is prepared by continuously casting in a twin roll caster and cooling to transform the strip from austenite to ferrite at a temperature range between 400° C. and 850° C. at cooling the strip to transform the austenite to ferrite within a temperature range between 400° C. and 850° C. at a cooling rate of greater than 100° C./sec without inhibiting the cooling rate to form cast strip that is less than about 1% austenite and has a packet size of at least 10% greater than 300 ?m, is either (i) a mixture of polygonal ferrite and low temperature transformation products or (ii) predominantly low temperature transformation products, and has a yield strength of at least 450 MPa. The cast strip before cooling is passed through a hot rolling mill to reduce the thickness of strip by at least 15% and up to 50%.

Abstract: A method of producing strip comprising the steps of assembling a pair of casting rolls with a nip between them, introducing between the casting rolls to form a casting pool of molten carbon steel having a total oxygen content of at least 70 ppm usually less than 250 ppm, and a free oxygen content 20 and 60 ppm, counter rotating the casting rolls, solidifying the molten steel on the rolls to form metal shells with levels of oxide inclusions reflected by the total oxygen content of the molten steel, and forming thin steel strip through the nip between the casting rolls from the solidified shells. The molten steel may have a total oxygen content is at least 100 ppm and the free oxygen content may be between 30 and 50 ppm. A unique steel strip may be obtained using the method having ductile properties.

Abstract: A steel strip made with protective layer of less than 100 nanometers with Fe203 adjacent the base metal of the strip. The steel strip may be made by assembling two casting rolls in lateral relationship to form a nip there between through which strip can be cast, forming a casting pool supported on the casting rolls above the nip at a temperature such that the temperature of the steel is greater than about 1,300° C. at the nip between the casting rolls, counter-rotating the casting rolls such that the peripheral surfaces of the casting rolls each travel toward the nip to produce a cast strip downwardly from the nip, and passing the continuous cast strip through at least one cooling chamber that has less than 5% oxygen to cool the strip to less than 150° C. or until coiled without disrupting the surface of the strip adjacent the protective layer formed.

Abstract: A method of producing cast steel strip having low surface roughness and low porosity by casting with molten steel having a total oxygen content of at least about 100 ppm and a temperature that allows a majority of any oxide inclusions to be in a liquidus state. The steel strip produced by the method may have a per unit area density of at least about 120 oxide inclusions per square millimeter to a depth of about 2 microns from the strip surface.

Abstract: A cast carbon steel strip is prepared by continuously casting in a twin roll caster and cooling to transform the strip from austenite to ferrite at a temperature range between 400° C. and 850° C. at cooling the strip to transform the austenite to ferrite within a temperature range between 400° C. and 850° C. at a cooling rate of greater than 100° C./sec without inhibiting the cooling rate to form cast strip that is less than about 1% austenite and has a packet size of at least 10% greater than 300 ?m, is either (i) a mixture of polygonal ferrite and low temperature transformation products or (ii) predominantly low temperature transformation products, and has a yield strength of at least 450 MPa. The cast strip before cooling is passed through a hot rolling mill to reduce the thickness of strip by at least 15% and up to 50%.

Abstract: A steel product with a high austenite grain coarsening temperature having less than 0.4% carbon, less than 0.06% aluminium, less than 0.01% titanium, less than 0.01% niobium, and less than 0.02% vanadium by weight, and having fine oxide particles containing silicon and iron distributed through the steel microstructure having an average particle size less than 50 nanometers and may be between 5 and 30 nanometers. The steel product may have fine oxide particles distributed through the microstructure capable of restricting ferrite recrystallisation for strain levels up to at least 10.0%, for temperatures up to 750 ° C. with holding times up to 20 minutes. The steel product may be made by continuous casting of steel strip introduced between the casting rolls to form a casting pool of molten carbon steel having a total oxygen content of at least 70 ppm usually less than 250 ppm, and a free oxygen content 20 and 60 ppm, counter rotating the casting rolls.

Abstract: A thin steel strip with low surface roughness and low porosity produced by casting with molten steel having a total oxygen content of at least about 100 ppm and a temperature that allows a majority of any oxide inclusions to be in a liquidus state. The steel strip produced by the method may have a per unit area density of at least about 120 oxide inclusions per square millimeter to a depth of about 2 microns from the strip surface.