Ca-treatment is an important aid to avoid clogging and to modify sulphides. The leading Austrian steel producer voestalpine Stahl GMBH in Linz treats Si-alloyed steel with CaSi wire to reduce the sulphur content in steel grades for gas tubes. Due to steadily increasing quality demands sulphide and oxide inclusions steels for galvanized hot-rolled strip have also to be modified. This type of steel grades is Si-free in order to guarantee the zinc coating adherence. This excludes CaSi wire for the Ca-treatment. An alternative to CaSi is CaFe wire. The aim of this work is to investigate the role of two different CaFe wires in the production of Si-free hot-rolled strip steel grades in theory and under industrial scale conditions. Main content of the practical work is the investigation of the Ca-treatment on the steel composition during and after ladle treatment, the recovery of the fed Calcium wire and the influence of the Ca-treatment on the modification of the non-metallic inclusions in the hot rolled band.