Pipe Manufacturing Process

ERW manufacturing facilities

The Capital Star Steel SA manufacturing plant in Mozambique utilises the latest and most advanced steel pipe manufacturing equipment, thereby ensuring the best quality standards possible. Our ERW pipe manufacturing facility meets all specifications set by leading oil and gas companies and international specifications, ensuring that we remain the benchmark of the steel pipe manufacturing industry.

Slitting line

Capital Star Steel SA has an in-house fully automated slitting line enabling us to slit milledge hot rolled coils to various widths, thereby allowing us to rapidly respond to customer needs for various diameters. This allows for minimised lead times and cost savings to the client.

Mill Entry

Slit coil is loaded onto the coil magazine from where it is fed into the decoiler. Coiled steel is then uncoiled, flattened and cropped before it is cross-welded onto the tail end of the previous coil. From here the continuous strip is fed into a spiral accumulator. This process ensures a non-stop manufacturing operation of pipe since strip is continuously fed into the mill.

ERW Pipe Manufacturing Process

The accumulator allows for the steel strip to be continuously fed into the forming section, where the pipes are formed longitudinally using a combination of forming passes and cage technology. This process also incorporates edge forming and is precisely controlled through fine adjustments in the forming cage. Mill set-ups for various diameters, wall thickness and steel grades are recorded in our mill set-up database, thereby ensuring accurate and repetitive quality.

After the forming process, the pipes are welded by high frequency induction (HFI). After welding, the HAZ is seam annealed using medium frequency induction heating and then air cooled. Pipes are then cut to length using a flying cutoff. Pipe lengths between 6 and 18 meters can be produced off the mill. All pipes are then end-faced to prepare pipe-ends for field welding or flanging as required by the customer. All pipes are hydrostatically pressure tested to specification requirements. The weld seams are then again ultrasonically tested by our highly skilled technical staff to ensure no cracks are formed during the pressure test process.