Hot Edge Induction Heating for Aluminium Cold Rolling Mills

The Hot Edge Induction System offers an advanced and efficient solution for managing strip-tight edges in aluminum cold rolling mills. By applying targeted heat at the strip edge position, the system expands the roll, reducing strip-tight edge issues. This allows for higher rolling speeds and fewer strip breaks, enhancing the overall efficiency of the rolling process.

During rolling, heat energy is transferred into the work roll directly adjacent to the strip. Coolant sprays then manage the roll temperature to ensure material flatness. However, thermal growth drops at the strip edge as heat energy from the rolling process conducts along the roll length. In this location, cooling sprays become ineffective in maintaining flatness, leading to tight edge issues.

Hot edge inductors apply targeted heat at the strip edge, expanding the roll and alleviating tight edge problems. This efficient technology delivers immediate process improvements and offers a quick return on investment. Hot edge inductors significantly enhance strip edge flatness, allowing mills to operate at higher speeds while maintaining the required product tolerances. Commonly used in aluminum cold mills, hot edge inductors are ideal for thin strips, foil, and can body alloys. The system can be retrofitted to most mill types, providing flexible integration into existing operations.

Induction Heating Head Construction

The induction heads use high flux density materials and low resistance Litz cables for superior performance and efficiency. Their liquid-cooled design ensures reliable operation at ambient temperatures above 250°C, ideal for high-temperature applications. Encased in durable epoxy resin, the heads resist wear, abrasion, and a wide range of chemicals, including most industrial solvents, ensuring long-lasting durability and consistent performance in challenging environments.

Operating Principle of the Hot Edge Induction Heating for Aluminium Cold Rolling Mills

The inductors are mounted on a precision mechanical positioning system to optimize strip edge heating. Two inductors are precisely aligned relative to the strip edges to ensure optimal positioning of the additional heating and prevent tight edges. The inductors are independently adjustable along the work roll barrel using hydraulic cylinders equipped with integral position transducers and linear motion slides to accommodate varying strip widths. The inductors retract for roll changes and extend toward the roll, calibrating the extension for roll size.

The Hot Edge Induction System includes the induction heating heads and auxiliary equipment for precise control and positioning. Hydraulic cylinders adjust the heating heads to maintain a specific air gap and strip width, achieving accuracy within 1 mm of the roll surface.

Benefits of Hot Edge Induction Heating for Aluminium Cold Rolling Mills

• Reduced downtime, fewer edge cracks and strip breaks
• Increased mill speed
• Lower bending force, resulting in less work roll wear
• Energy efficient: 90% efficiency and only operates during passes
• Cost savings: uses <10% of the energy used by hot edge sprays.
• No additional requirements for coolant volume, pump flow, fume extraction, or waste rolling oil