Apparatus for removing slag from the top surface of metal shapes including a conveyor belt and a pair of vertically adjustable impact units located above the conveyor belt. Each impact unit has an impact element head driven by an electric motor and is attached to a screw jack for adjusting its vertical position. The impact units and a portion of the conveyor belt are surrounded by a closed cabinet having inlet and outlet openings for the conveyor belt and the metal shapes carried thereon. The impact element head in each unit is a disc connected to a support plate. The disc has peripheral grooves in its surfaces and radially aligned pairs of holes connecting the grooves throughout the circumference of the disc with a flexible steel cable extending from the groove in one surface of the disc through each pair of radially aligned holes and through the groove in the other surface of the disc so that its ends extend past the surface of the disc to contact slag on the top surface of metal shapes passing below the impact heads on the conveyor belt.
