Development of Ultra Fast Cooling Variable Frequency Control System in Hot Strip Mill

Abstract

With advanced high-strength steels and high value-added steels development, it is urgent to innovative run out table cooling line in hot strip mill with flexible cooling capacity to meet products metallurgical requirements of the cooling rate after rolling. The way to increase the cooling capacity is to improve the effect of heat exchange of water forced convection with hot strip. Then to raise the spraying pressure to penetrate the residual water and break the vapor inside it is the most feasible method. So, how to control the variable frequency device providing variable spraying pressure is the object of this study. Firstly, cooling after rolling process requirement under ultra fast cooling was analyzed; secondly, characteristic curves of centrifugal pump and water supply pipeline were tested; then inverter timing control, interlock control, security control and so on were studied. Since online application of the variable frequency control system, the water supply system has been running stably and reliably

Microstructural and mechanical properties of ultra-high-strength dual-phase steel produced by ultra-fast cooling

“…Hot-rolled high-strength steels are generally produced by adding a large number of alloying elements [9]; however, this method significantly increases the production cost and also deteriorates the welding properties of steels. With the development of the thermomechanical control process (TMCP), the ultra-fast cooling technology (UFC) is used to control the phase transition in steels [10,11]. However, the roles of a large number of deformed substructures retained by UFC in hot-rolled ultra-high-strength DP steel have not yet been systematically discussed [12].…”