A mathematical model is developed based on the reaction kinetics and mass balance to investigate the decarburization rate based on operational parameters of the UHP electric arc furnace charged with hot metal. Thus, the evolution of carbon content can be described accurately, and the carbon content at the end of melting can be controlled dynamically. The calculated results are in good agreement with the production data of a 150 ton DC-UHP electric arc furnace. Simulated results show that the decarburization rate is proportional to the flow rate of oxygen at high carbon contents, to the square root of carbon content at intermediate carbon contents, and to the carbon content at low carbon contents. The decarburization rate, especially at low carbon contents, can be enhanced by bath agitation. For optimum operating conditions, less oxygen flow rate is required as the carbon content decreases.
