Method for producing a tube of glass

A method for producing a tube (22) of glass by forming a hollow cylinder (2) from glass with a first outer diameter D1, the method comprising

• while the hollow cylinder is rotating about a rotation axis (6), softening the hollow cylinder in portions in a heating zone (20) which is moved at a relative feed rate Va to form a softened portion and radially expanding the softened portion under an action of a centrifugal force and/or of an internal overpressure applied in a bore (7) of the hollow cylinder (2) so as to form a deformation zone (30), the tube (22) being shaped continuously to a second outer diameter D2 which is greater than the first outer diameter D1,
• wherein the radial expansion of the softened portion is carried out at a location-dependent radial expansion rate Vr, a profile of which along the deformation zone (30) has a maximum value Vr, max, Vr, max being smaller than 20 cm/min,
• wherein the radial expansion of the softened portion is such that the tube (22) is produced at the second outer diameter D2 which is greater by at least 70 mm than the first outer diameter D1 in a single forming step, and
• wherein the heating zone is subdivided into a front heating portion assigned to a beginning of the deformation zone and a rear heating portion assigned to an end of the deformation zone, with a higher temperature being generated on a surface of the deformation zone by the front heating portion than by the rear heating portion, such that a temperature towards the end of the deformation zone is lower than a temperature at the beginning of the deformation zone.