Abstract: According to this process: the position in respect of height of the "molten metal (2)/liquid slag (3)" interface (M) is continuously determined. Further the position of an isotherm (IS) located at the "liquid slag (3)/powder layer (4)" interface is continuously determined by automatically controlling the position of a thermocouple (8) on this isotherm and by measuring the displacements of this thermocouple.By comparing the position in respect of height of the molten metal/liquid slag interface (M) with the position in respect of height of the isotherm (IS), the thickness and thus the variations in thickness of the liquid slag are continuously deduced.

Abstract: Process and apparatus for preventing defects in the symmetry of rolled H-beams or I-beams, i.e., a faulty position of their webs (4) in relation to their flanges (5), by correcting such defects in situ. The differential between the torques applied to the upper and lower rolls (1,2) of the rolling stand is determined and compared to a predetermined threshhold value (.delta.). Any excess of the measured value over the threshhold value is eliminated by correction of the elevation of the inlet table of the rolling stand so as to reduce the measured value to below the threshhold value.