Speaker
Description
A knowledge driven, physically based and reliable determination of process parameters during hot rolling is crucial for the accurate prediction of final product properties and for the precise layout and design of hot strip mills.
Based on known initial conditions of the material and accurate product tracking, the evolution of physical properties can be calculated based on the time-temperature deformation path. For this purpose, several detailed sub-models are required to describe, e.g. temperature evolution due to heat generation and heat radiation, convection and conduction or considering the effects of descaling. The same holds for the prediction of heat loss and phase transformations while passing the material through a transfer bar cooling unit, a heat cover its thermal equilibration inside a coil box or the impact of inductive heating and fast cooling along the cooling line.
Based on metallurgical process parameter settings, the calculated interaction between mill and material in terms of temperature evolution, deformation induced work hardening and resulting forces and torques provide direct input for dimensioning of the force and power requirements of mill stand and drives. Moreover, the model results are also utilized for dimensioning of several other components of a hot strip mill like shears, profile and flatness actuators, cooling equipment or downcoilers. Calculation of metallurgy relevant intrinsic parameters such as states of precipitates and microstructural morphology provide the basis for the prediction of phase transformation kinetics and physical properties such as yield and tensile strength.
A detailed analysis of the product mix enables throughput evaluations based on a variety of pass and cooling schedule optimizations allowing accurate predictions on operational expenses and return on investments to be expected. The feedback from existing rolling mills is used as an input for the fine tuning and continuous improvement of the detailed models.