Method for casting metal strip with edge control

A casting roll control system with adjustable circumference control for use in a twin roll caster for producing cast strip metal, comprising:

• a casting roll including a casting surface formed by a cylindrical tube;
• a logic controller;
• a first expansion ring disposed within the cylindrical tube and under a step which forms a shoulder of the casting surface, the first expansion ring having at least one heating element and at least one temperature sensor adapted to provide signals indicative of expansion ring temperature, the at least one temperature sensor being coupled to the logic controller, the first expansion ring being formed of a material that expands an outer diameter of the first expansion ring when heated by the at least one heating element, thereby expanding an outer diameter of the casting surface corresponding to a location of the first expansion ring;
• and
• a plurality of strip thickness sensors adapted to provide output signals indicative of a thickness of a cast strip capable of being arranged to make thickness measurements across a width of a cast strip in a line substantially perpendicular to a casting direction including an edge thickness and being coupled to the logic controller;
• wherein the logic controller is configured with instructions stored in non-volatile memory to receive thickness measurements from the strip thickness sensors and temperature measurements from the at least one temperature sensor, fit a curve to the thickness measurements, determine a target edge thickness of the cast strip based on the curve, determine a delta thickness as a difference between the measured edge thickness and the target edge thickness and cause an amount of power applied to the at least one heating element to be adjusted to reduce the delta thickness.