FIELD: manufacture of tubular products. SUBSTANCE: elastic deformation holds the complex blank closed so that a complete pipe or a length thereof is produced. A closed seam is resorted to in this particular case to lock the blank edges. The blank is bent or flanged parallel to the axis of the pipe or the length thereof. A gap is formed between the longitudinal blank edges in the disjointed condition, enabling another component to be inserted into the gap. The disjointed blank is given a configuration in cross section which provides for obtaining the product of the specified configuration in cross section under the forces and moments coming on the closed seam. EFFECT: simplification of the manufacturing technique. 22 cl, 21 dwg
