A PROCESS-ORIENTED MODEL FOR THE DEGASSIN G OF STEEL HEATS

A simple thermodynamics- and reaction kinetics-based model designed fo r different secondary metallurgy degassing processes is described. Tak en into account in this respect is that, during the vacuum treatment, the degassing mainly takes place just beneath the bath surface where c onsiderable additional pressure develops in the ascending bubbles in r elation to their environment. The decarburization monitored on the bas is of waste gas measurements is compared with the modelled dependences of the decarburization rate on the carbon concentration for the ultra low decarburization of low-alloy steels in ladle-tank and recirculatio n degassing as well as for the refining of high-chromium steels in a v acuum and in a converter, and the model parameters are identified. Sim ulation data taken from literature are used as a means of comparison f or dehydrogenation and denitrogenization in ladle tank degassing.