A post mortem MgO-C brick of a steel ladle (slag line) was studied to identify the main causes of a localized wear, produced at initial taps. The extreme low thickness of the lining provokes ladle removed from service. In addition, slag infiltration into the upper horizontal joint promotes corrosion. The slag line presents cracks with a propagation pattern considerably parallel to the hot face. In order to identify the wear mechanisms, the results of the postmorten study were compared with information of the characterization of one brick without use.Fil: Brandaleze, Elena. Universidad Tecnológica Nacional. Facultad Regional San Nicolás. Departamento Metalurgia. Centro DEYTEMA; Argentina.Fil: Benavidez, Edgardo. Universidad Tecnológica Nacional. Facultad Regional San Nicolás. Departamento Metalurgia. Centro DEYTEMA; Argentina.