Start-up billet head for a continuous casting machine for metal, in particular, steel

A start-up billet head for a continuous casting machine for metal closes off an outlet of the casting die before start-up of the casting process. The start-up billet head has a coupling part facing an interior of the casting die and forms together with a billet cast in the casting die a positive-locking, hook-shaped connection. The connection can be decoupled after leaving the casting die by performing a tilting movement of the start-up billet head about a joint of the start-up billet. The coupling part has a recess with a first side active in a billet removal direction and a second side facing the first side. The first and second sides have oppositely oriented arc shapes. The coupling part has the shape of a preliminary billet profile with at least one undercut located in the area of at least one flange or angled joint of the preliminary billet profile.