Having become the southern African distributor for Polysoude orbital welding systems, Renttech SA held an orbital welding open day at its Secunda branch. African Fusion’s Peter Middleton attends and talks to welding specialist, Eduan Naude.
Renttech SA, according to Naude, has been looking at how to help clients to implement more automated solutions for several years. “To improved productivity and quality, we know that out fabricators have to adopt automation to remain competitive against imports,” he begins. “For several years now, we have been looking for new opportunities and partners that could help us improve our offering and the capabilities of our local industries, “ he says.
Hence the signing in November 2016 of a partnership agreement with Polysoude, an acknowledged global leader in orbital TIG welding technology.
“While orbital TIG welding is not unknown in South Africa, systems have generally been supplied from overseas and most have remained locally unsupported. In Polysoude, we have found a state-of-the-art equipment developer willing to train our local Renttech team and to offer continuous and ongoing welding and technical support,” Naude adds.
Why is orbital welding important? “We have seen a serious shortage of the number of skilled welders required in the tube and piping market, which is currently being filled by importing OCN (other country national) welders.” Naude responds.
“We believe it will be far better to put in some automation and then upskill our own people to operate these. Orbital welding systems take the manual manipulations skills out of welders’ hands, but the technical skills to prepare the joint and set up the equipment 100% correctly remains an essential aspect of the process,” argues Naude. “This requires a sound knowledge of the process and ongoing attention to the finer details,” he adds.
Naude has significant experience in orbital TIG welding, having spent years producing joints for the reheaters and superheaters for the Medupi and Kusile new-build projects. “This work involved producing 132 000 orbital welds over a six to seven year period. And while this work is now completed, the project highlighted the value and possibilities available from the process,” he notes.
“We now have the experience and can offer training, procedure development, welding support and technical services from our nationwide footprint of branches, and we can reference some high-level successes from the past. In addition, Polysoude has a massive amount of global experience that it is willing to share with us, and an R&D capability that we can access for customised solutions and/or procedure development,” Naude assures African Fusion.
Outlining the key principle of Polysoude orbital welding solutions, Naude says that a TIG welding torch travels around the tubes to be joined, guided by an orbital welding head clamped onto the pipe.
Systems are available for tube-to-tube; pipe-to-pipe; and tube-to-tube sheet welding; and butt welds, fillet welds, flange joints, bends, T-fittings and valves on a comprehensive range of tube and pipe material types can be accommodated.
For thick-walled piping the use of narrow-gap technology, which reduces the total amount of weld metal required by reducing the pipe-end preparation – in some cases to 3.0° – makes the technology attractive with regard to weld speed and quality.
“As a company strong in the petrochemical industry, we see significant opportunities there, but in respect of orbital TIG welding particularly, our current focus is on power generation on the repair and maintenance side. This work typically involves joining new to old piping, which comes with issues such as pitting corrosion, out-of-roundness and fit-up mismatch, all of which require robust welding systems and procedures for success,” Naude tells African Fusion.
He cites a current trial involving new-to-old boiler pipe of varying sizes.