Tube for pouring liquid metal, assembly of a tube and a metal frame and metal frame

Tube for pouring liquid metal from a metallurgical container, the tube delimiting a pouring channel having a pouring axis (X), comprising a downstream part, in which the pouring channel has a diameter known as the outlet diameter (Dout), and an upstream part which is defined as being that part of the tube that lies between an upper transverse plane (Psup), tangential to the upper end of the tube, and a lower transverse plane (Pinf) lying a distance (L), known as the threshold distance, from the upper transverse plane (Psup), the threshold distance having a dimension greater than four times the outlet diameter (Dout), the upstream part being flared and being configured in such a way that:

• its upper end has a convex overall shape in the axial direction (X) and has a surface of intersection with the upper transverse plane (Psup) of which the width (e) in the radial direction (Y) is less than half the outlet diameter (Dout),
• the upstream part is included within a first volume corresponding to the complementary part of an axisymmetric frustoconical volume (V1) having as its axis the pouring axis (X), and the generatrix of which forms an angle alpha (a) greater than 5° with the pouring axis (X), the small base of the frustoconical volume (V1) corresponding to the surface of intersection of the lower transverse plane with the pouring channel,
• the upstream part is included within a second volume (V2), delimited by a surface of revolution generated by an isosceles trapezium revolving about the pouring axis (X), the small base of the trapezium lying in the upper transverse plane (Psup), having as its centre the centre (C) of the upper end of the tube and as its dimension a width (E) equal to half the outlet diameter (Dout), the large base of the trapezium lying in the lower transverse plane (Pinf) and the two non-parallel sides of the trapezium together making an angle beta (β) less than 30°, and
• an outer wall of the upstream part of the tube contains a portion with a radius of curvature that is convex in vertical profile with respect to the body of the tube.