PWS GmbH has been contracted to build a new two-stage spiral pipe-welding plant for China’s Shandong Shengli Steel Pipe Co. Ltd. The value of the contract has not been reported, but the new plant is due to be online by September 2011 producing up to 240,000 metric tons/year of welded tubular products.

Shandong Shengli Steel Pipe is a part of Shengli Oil and Gas Pipe Holdings Ltd. that supplies pipes to the nearby Shengli oilfield, one of China’s largest petroleum-drilling regions, with reserves estimated at 4.8 billion tons (351,840,000 barrels) and natural gas reserves estimated at 230 billion cubic meters. The site is in eastern China, near Dongying, in Shandong province.

PWS is an operating subsidiary of the SMS Group, having been acquired by the plant builder in 2009. In addition to spiral-welding machines PWS manufactures pipe-end finishing machines, hydrostatic pipe testers, and similar products, along with automation systems and peripheral devices and material handling equipment.

The plant being developed for the Shengli site will be an integrated operation, consisting of prewelding process systems, a spiral pipe forming and tack welding machine for hot-rolled steel strip, and a downstream finish welding stands. Shengli will be able to produce low-carbon steel pipes from 24 to 64 inches diameter, mostly for natural gas and oil pipelines.

“For our welding technology we employ welding current sources without transformers,” detailed PWS managing director Michael Stark. “The important parameters for a stable welding process that are normally generated by means of electrical components in the welding current source are now modulated flexibly by power electronics. Through the elimination of the welding transformer and other electrical components in our welding technology, we achieve efficiencies of over 90 percent. The result is an energy saving of over 30 percent compared with the older technology.”

The energy-saving welding technology also makes it possible to weld at a significantly faster rate, with no negative effect on the stability of the welding process. PWS attributes this to modern current source technology and process control.