Spiral Pipes Manufacturing Process

Spiral pipes are produced from hot rolled coils produced in steel plant. All the incoming coils are verified for its chemistry & mechanical properties as per the test certificate received from the steel plant to meet specification requirements.

The Spiral Pipe manufacturing process involves setting of the mill entry line as per the calculated angle with respect to centre line of pipe & forming cage to the required diameter. The coils are opened, leveled in leveler & end sheared to facilitate joining of incoming & outgoing coils & joined by Submerged Arc Welding to maintain production continuity. Subsequently it is guided & its edges are milled to get the desired edge. It is then formed at the forming table on the principle of three roll bending to get the required diameter & auto SAW welded from inside. Since the strip is being fed continuously inside welding operation is also continuous. At about 180 degree phase, continuous outside auto SAW welding is carried out so that string of formed pipe is welded from both sides. It is then cut to the required length by Plasma equipment at the cut off equipment. Individual pipe is serially numbered for its traceability. During forming & welding, weld gap at inside welding is maintained by gap control unit to get adequate fusion from inside.

All the pipes are then inspected from inside as well as outside to find defect in the weld or body, diameter, forming defects etc. Pipes requiring rectification are manually rectified by manual welding &/or grinding depending on the nature of defect. Pipe ends are then beveled. Each pipe is then hydrostatically tested as per the calculated pressure; it is then inspected before offering to the customer’s inspectors. Accepted pipes are then paint stenciled as per the requirement before shifting it to the storage yard & subsequent dispatch.