Abstract: In order to ensure stable production and uniform microstructure of hot-rolled dual phase in CSP rear ultra-fast cooling (UFC)， the high-precision control of the cooling water pressure should be achieved in strip production process. For the problem of the pressure fluctuation in the cooling process of strip， the methods which united power pump closed-loop control and valve fuzzy control， and interlocked power pump closed-loop control and valve closed-loop control were designed by binding technology and equipment features of Baotou CSP rear ultra-fast cooling system. It was found that the head-tail control range of collector pipe pressure is 0.85±0.05MPa， and the middle control range of collector pipe pressure is 0.85±0.01MPa in the actual application. The high-precision control of the cooling water pressure is achieved in low-cost hot-rolled dual phase cooling process of the rear UFC system， and it satisfies the production requirement of hot-rolled dual-phase steel.

Key words: compact strip production(CSP), ultra-fast cooling, water pressure, uncooled head, uncooled tail, control method