The invention relates to a continuous casting nozzle assembly (10) for casting, in particular for upward vertical casting, of a metallic, in particular a non-ferrous, pipe, which is suitable for uninterrupted casting, which nozzle assembly comprises a nozzle (11), a mandrel (12) and a cooler (15). Surface roughness of at least part, in particular of the dwindling area (Z), of inner surface of the nozzle (11) of the nozzle assembly (10) is 1-8.0 Ra, advantageously 3-5 Ra.