Intumescent sealing for metal casting apparatuses

Refractory element of a nozzle assembly for a metal casting apparatus, said refractory element comprising a first through bore opening at a first, substantially planar coupling surface configured for being coupled in a sliding translation relationship with a second coupling surface of a second refractory element, wherein the first coupling surface of said refractory element is provided with a sealing member comprising a thermally intumescent material, wherein said first planar coupling surface is a surface selected from the group consisting of:

• the coupling surface of a pouring nozzle configured for being loaded in and unloaded out of a tube exchange device in sliding relationship with a corresponding contact surface of an inner nozzle embedded within the floor of a tundish;
• the coupling surface of an inner nozzle configured to be mounted in the bottom floor of a tundish and fixed to a tube exchange device such that said coupling surface enters in sliding relationship with a pouring nozzle upon introduction of the latter in said tube exchange device;
• and
• the coupling surface of a slide gate device plate such that said coupling surface enters in sliding relationship with the coupling surface of a second plate of said slide gate, and wherein the sealing member comprises:
• 5-95 wt. % of an intumescent material consisting of expandable graphite;
• 5-95 wt. % of a binder consisting of water glass and clay;
• 0.1-80 wt. % of a lubricant consisting of nonexpendable graphite;
• and
• 0.1-20 wt. % of an antioxidant consisting of aluminum;
• wherein the wt. % are measured as solids dry weight with respect to a total dry weight of the sealing member composition.