The invention proposes an assembly (1) comprising: an exhaust casing (20), rotating about an axis (X-X), comprising a flange (23) for attachment to a mounting (42); a sealing plate (30) for rotation about the axis, the plate being added to the attachment flange of the casing and having a radial section comprising: a radially inner end portion (32), a radially outer end portion (34), and a bend (31) extending between the two end portions, said portions forming therebetween an angle of 80 to 100 degrees, the outer end portion having a length in an axial direction (L34) equal to 15% to 35% of the height (H) of the plate measured in the radial direction around the rotation axis, the outer end portion extending parallel to said axis, and said bend being open in the downstream direction relative to the flow of air.