in an axial direction a more or less coinciding with the transport direction as well as beside one another in the circumferential direction wherein gas outlet openings 15 are disposed directly in curved mandrel surface 16 of mandrel 3 constituted as a lateral cylindrical surface and not offset radially inwards with respect to the latter in the example of embodiment according to fig2 the mandrel is constituted at least in sections by a porous material 18 e g polished metal foam which comprises a multiplicity of gas outlet openings 15 constituted by micropores which are disposed beside one another both axially and in the circumferential direction in such a way that an air cushion is thus ensured the compressed air is also conveyed through optional heating means 14 in the case of the example of embodiment according to fig2 fig3 shows a longitudinal cross section of a mandrel 3 in an alternative representation the latter is internally hollow and can be acted on with compressed gas in particular compressed air wherein the compressed gas migrates through microporous mandrel material 18 in the radial direction outwards the microporous material is preferably a metal foam for example an aluminium foam which if need be is provided with stabilisation additives with the aid of the compressed gas an air cushion is formed between tubular shape 4 formed from a substrate 2 and mandrel 3 tubular shape 4 is transported in transport direction r with the aid of combined pressure application and conveying means 19 which in the shown example of embodiment comprise a forming strap 20 which is pressed radially inwards against tubular shape 4 in order thus to generate static friction between forming strap 20 and flexible tubular shape 4 so that.