THERMODYNAMIC STUDY OF EXCHANGE-REACTIONS IN THE MANUFACTURING OF MICROALLOYED STEELS BY THE ESR PROCESS

With the aim of manufacturing 42CrMo4 steel by the electroslag remelti ng process (ESR) with a certain Ti and Al content and uniform distribu tion throughout the ingot, a study has been made of the complex metal- slag reactions which take place, especially of the most reactive eleme nts. The thermodynamic activities of the elements in the molten metal and of the oxides in the slag were calculated and theoretic oxidation equilibria of the elements with greatest affinity for oxygen were prop osed, as well as their exchange equilibria. Comparison of the theoreti c equilibria with experimental results permits interpretation of how t he system evolves during remelting and adjustment of the slag composit ion and other parameters in order to manufacture a steel of a certain composition and uniform from the bottom to the top of the ingot.