Fabrication of small size seamless reservoirs by tube forming

The purpose of this paper is to introduce an innovative manufacturing process that is capable of shaping industrial tubes into small size, seamless, reservoirs made from a variety of materials and available in many shapes. The process is carried out by axial pressing the open ends of a tube against two shaped dies, while providing internal support by means of a low melting point (recyclable) mandrel, until achieving the desired shape of the reservoir. The elimination of weld seams leads to major improvements in economy and reliability and offers potential for fabricating reservoirs in medium to large batches for a wide variety of industrial and commercial applications.Special emphasis is given to practical aspects related to the tools and techniques that were utilized for fabricating spherical reservoirs and cylindrical reservoirs with semi-ellipsoidal ends.The presentation is supported by experimentation and numerical modelling based on independently determined mechanical properties of the materials with the purpose of understanding the deformation mechanics, identifying the formability limits and demonstrating the overall performance and feasibility of the proposed manufacturing process.

► Innovative manufacturing process for shaping tubes into seamless reservoirs.
► Process makes use of sharp edge dies and internal, recyclable, mandrels.
► Collapse by local buckling and wrinkling is avoided.
► Forming load facilitates industrialization in a low-cost, small capacity, press.