A wire feed unit (1) for the controlled feeding of wire from a coil into a steel melt in a ladle for purposes of introducing additives into the melt, comprises a water cooled guide tube (2, 3) of length capable of imparting a straightening effect on wire fed along the guide tube (2, 3) and of allowing the uncontrolled wire leaving the guide tube to be close to its point of penetration of the steel in the ladle. The invention also includes a ladle arc furnace (L) provided with a unit (1).