Abstract: The facility is comprised of an oven (8) fitted with rotating supports (3) disposed parallel to each other, upon which preformed tubes (11) rest and rotate, which are introduced from a feeder (14) where they are contained at room temperature for their homogeneous circumferential heating inside said oven (8). Additionally, transverse displacement means (5, 6) are disposed inside the oven (8) in order to facilitate the elevation and transverse displacement of the preformed tubes (11), in such a manner as to favour the progressive and uniform heating throughout the thickness of said preformed tubes (11). On the other hand, it features assemblies that generate heating currents (15, 10, 2) comprised of elements (15), fans (10) and deflectors (2) longitudinally distributed in sectors or quadrants inside the oven (8), for the purpose of heating and distributing the air over the preformed tubes (11).