THERMODYNAMIC ASPECTS IN THE MANUFACTURING OF MICROALLOYED STEELS BY THE ELECTROSLAG REMELTING PROCESS

In this paper the possibility is demonstrated of producing microalloye d steels with Ti, V and Nb using electrodes composed of finished steel s freely available on the open market. The addition of ferroalloys to the slag pool was carried out at intervals of 1 min and it was confirm ed that this interval was sufficient to obtain an acceptable microallo ying distribution in the metal pool. Deoxidation was carried out with Ca-Si at rates of between 1-1.5 kg/t and it was confirmed that metal/s lag reactions in the production of microalloyed steels with V and Nb a re easily controllable, a uniform composition being obtained from the bottom to the top of the ingot with these metals. However, in the case of steels with Ti it was necessary to prevent the Si/Ti exchange reac tions which were produced when the slag did not contain SiO2 and when the rate at which Fe-Ti was added was low. In the case of microalloyed steels with Nb and with V a thermodynamic equilibrium between the Al, Ca and 0 was obtained. However, in the case of steels with Ti the equ ilibrium was produced between the Al, Ti and 0.