High-Precision Header Flux Control of Ultra-Fast Cooling in Hot Strip Mill By PI Controlle

Abstract

A new header flux controller of an ultra-fast cooling (UFC) system was investigated during hot strip rolling. The UFC header flux was calibrated by changing the opening rate of the adjusting valve from 0% to 95% and, reversely, from 95% to 0%, in increments of 5%. The results showed that the header flux was rarely influenced by the changing direction of the adjusting valve. Based on the analysis of the flux adjusting, the definition of adjusting-efficiency (A-E) of flux was introduced and the corresponding equation was established. A Proportion-Integral (PI) controller, based on A-E, was employed to implement the closed-loop control of the header flux. The results from the on-site implementation indicated that the flux deviation between target and measured values was less than ±1.0m3/h.