Thermodynamic Analysis of Removing the Non-Metallic Inclusions from the Molten Steel During Continuous Casting Process
DOI:
https://doi.org/10.20535/1810-0546.2018.3.136570Keywords:
Steel, Coagulation, Non-metallic inclusions, TundishAbstract
Background. Nowadays the main directions of the metallurgical production development in our country are the improvements of the metal quality, caused by the increased competition on both the internal and the world markets. One of the main requirements for the high quality steel is low content of the non-metallic inclusions in the finished product, as well as their uniform distribution along the metal blank cross-section. The manufacturing of the high quality metal has become possible, for some time now, because of its refining in the molten state at the last stage of casting in the tundish. Investigations in the casting device under the industrial conditions are limited, because of the physical conditions of the process being carried out, the too large size of the casting device and high temperature in particular. These limitations can be overcome, if the experiments are carried out not on the conventional device, but on the physical model with the further investigation of the metal quality, taking advantage of the metallographic methods.
Objective. The aim of the paper is the quality improving of continuously cast steel.
Methods. Thermodynamic analysis of coagulation and removal of non-metallic inclusions into slag have been applied. Investigation of hydrodynamic processes occurring in the tundish during continuous casting, which contributes to the removal of nonmetallic inclusions. Metallographic methods of investigation of finished product (steel).
Results. The thermodynamic analysis of the disperse system of molten steel–non-metallic inclusions has shown that metallic films (layers) are formed on top of non-metallic phase particles. Physical modeling of hydrodynamic flows showed that the most effective structure of flows, which promotes the coagulation of nonmetallic inclusions, is a vortex type system. Industrial tests have shown that metal samples that were obtained with the use of “reaction chamber” contain 40–80 % less of non-metallic inclusions.
Conclusions. In order to create the most favorable conditions for the coagulation of the non-metallic phase in the tundish, it is necessary that “reaction chamber” is used during the process. The data of thermodynamic analysis and physical modeling correspond to data of industrial tests.References
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