World’s largest continuous ERW tube welding machine

The highly automated ERW (electric resistance welding) tube welding line in Blytheville (Arkansas), USA started operation in mid-2021. With a capacity of more than 400,000 tons per year, the new 28-inch plant complements the Atlas Tube division of Zekelman Industries.

Greater product diversity for the North American market

Zekelman uses the new 28-inch ERW tube welding line to manufacture structural and piling tubes with diameters ranging from 10 3/4 to 28 inches (273 to 710 mm) and wall thicknesses of up to 1 inch (25.4 mm). In addition, it is possible to produce square and rectangular hollow sections with dimensions of 8 x 8 inches (203.2 x 203.2 mm) up to 22 x 22 inches (558.2 x 558.2mm) or 34 x 10 inches (863.6 x 254 mm).

For the North American market, this means a more diverse product range for HSS products (hollow structural sections) that find various end uses in infrastructure and building construction. Moreover, with this line, Zekelman Industries is also able to manufacture products larger than 20 inches on an ERW tube welding line for the first time in the US.

This 28-inch ERW tube welding line uses PERFECT arc^® welding technology for the cross joining of strip up to 25.4 mm thick. The PERFECT arc^® welding system, which was developed and patented by SMS group, is a GMA (gas metal arc) tandem welding process, i.e. a set of tandem torches apply single-wire gas metal arc welds. Thanks to its ability to cross-weld the 25.4 mm thick coil ends in only one welding pass with reliable fusion results, it significantly reduces cycle times in the cross welding station and so increases the productivity of the entire plant. Welding is performed at up to 800 amps per wire.

The PERFECT arc^® inverter welding power sources feature digital technology, which can deliver efficiency levels over 90%. Depending on the operating point, energy savings of up to 30% can be achieved compared to welding power sources that still use conventional thyristor technoloy.

The design and configuration of the new welding line meet the strictest requirements regarding product quality and throughput. The X-Pact^® Quicksetting system enables short changeover times for ERW welded tube plants. The smart X-Pact^® Quicksetting system provides for an automatic adjustment of the rolls to their new working position after a size change. Thanks to a data-based approach for system adjustments, changeover and setting times in the line are minimized, productivity is increased, and continuous improvements in product quality is guaranteed. The system fulfills the current requirements for high flexibility in production with ever-smaller batch sizes and wider production mixes. With the X-Pact^® Quicksetting roll management module, the ideal configuration and the required rolls for the subsequent tube format can be planned while production is underway.