Model Algorithm Research on Cooling Path Control of Hot-rolled Dual-phase Steel

With the development of advanced high strength steel, especially for dual-phase steel, the model algorithm for cooling control after hot rolling has to achieve the targeted coiling temperature control at the location of downcoiler whilst maintaining the cooling path control based on strip microstructure along the whole cooling section. A cooling path control algorithm was proposed for the laminar cooling process as a solution to practical difficulties associated with the realization of the thermal cycle during cooling process. The heat conduction equation coupled with the carbon diffusion equation with moving boundary was employed in order to simulate temperature change and phase transformation kinetics, making it possible to observe the temperature field and the phase fraction of the strip in real time. On this basis, an optimization method was utilized for valve settings to ensure the minimum deviations between the predicted and actual cooling path of the strip, taking into account the constraints of the cooling equipment's specific capacity, cooling line length, etc. Results showed that the model algorithm was able to achieve the online cooling path control for dual-phase steel.