Abstract:
A mathematical model was developed to simulate Unigal's Continuous Galvanizing Line (CGL) and identify the variables that most affect the performance of the thermal cycle. Several aspects of the process were considered, such as heating system, gas jet cooling, radiant tubes, fuel gas consumption, hydrogen-nitrogen gas mixture concentration, steel strip properties and geometry, blowers, and heat exchangers. The model predicts process conditions along the production line: number and capacity of burners segmented by zones, strip temperature, strip cooling and heating rates, and plots cooling curves on Continuous Cooling Transformation diagram (CCT). The model is versatile, as example, a simulation of increase from 3% to 10% hydrogen concentration in HN gas results in savings of electricity consumption of 17% to 33%.
The model was validated from tests carried out at CGL's industrial plant where calculate values by the model agree to within ± 10 % with the actual production data.