A glass frit composition having the theoretical oxide values (in weight %) of 0.5-9 Li.sub.2 O, 29-38 Na.sub.2 O, 0-25 CaO, 5-10 B.sub.2 O.sub.3 and 38-50 of SiO.sub.2 is characterized in that it is virtually fluorine-free and was found to be eminently suitable in its molten form as a lubricant in the continuous casting of steel. The invention is thus related to a lithium containing fluorine-free frit compositions and in a second aspect to an improvement in the process for the continuous casting of steel, the improvement comprising using as a lubricant the glass frit composition referred to above.
