The fundamentals for efficient and economical roll cooling are an optimized nozzle and header arrangement. In the process of rolling the most significant aspect is the generation of heat through friction and deformation in the roll bite.
The most important aspects are:
- Maintaining uniform, stable roll temperatures, circumferentially around the roll and transversely across the roll width
- Creating optimum thermal crowns and minimum differential in temperature in the upper and lower work rolls with optimum heat extraction
Because of the current demands on mills to process much lighter exit gauges from increased incoming hot strip thickness, much larger reductions are necessary on individual mill stands, such high reductions at a nominal width result in a larger area of contact with corresponding higher rolling force, friction and heat generation.
These high reduction schedules combined with the requirement to produce widening range of material cross-sections with a more diverse range of softer and harder materials also result in increasingly greater challenges in the control of roll temperature and the effective transfer/extraction of heat.