An immersion nozzle for use with an immersion nozzle replacement apparatus, capable of preventing crack formation due to the presence of a neck region. The immersion nozzle includes a nozzle body, a flange, and a metal casing. The nozzle body is formed such that a region of an outer peripheral surface thereof located above a point of power of an upward supporting force from a supporting device extends vertically up to an upper edge of the nozzle body without any dimensional change with respect to an central axis of an inner bore of the nozzle body. The outer peripheral surface region is not joined to the metal casing.

Refractory casting nozzle for a changing device arranged at the outlet of a metallurgical vessel is provided with a top side refractory plate, which is provided with an abutting surface at each of two opposing end faces. During a change, the casting nozzle can either be moved against the one abutting surface of a top side plate of an adjacent casting nozzle or be pushed out from this casting nozzle. This top side plate is provided, in the one abutting surface, with a centering element protruding on both sides of this and in the opposite abutting surface with a bevelling on both sides, designed such that, during a change, the casting nozzle cooperates, with its centering elements with the bevellings of the adjacent identically designed casting nozzle, thus bringing about a guiding of the two casting nozzles.