Electrical Power & Protection


Rotary friction welding – a first for Tutuka power station

January 2025 Electrical Power & Protection

Steinmüller Africa, a leader in high-pressure steam generation equipment, has successfully used rotary friction welding in a project with engineering consultant, eNtsa. This innovative technique was applied to fabricating four headers used for high-pressure water heater boiler units installed at Tutuka power station in Mpumalanga.

The duo used a hybrid of rotary friction welding and friction hydro-pillar processing (FHPP) to attach 448 heat exchanger nozzles onto each of the four high-pressure headers used in the final fabrication of the high-pressure heat exchangers. This process was developed as an alternative to the current submerged arc welding method. “The nozzles need to be precise to ensure a proper fit between the tube and nozzle weld,” explains Friedrich Schwim, senior welding engineer at Steinmüller Africa.

The initial welds using the submerged arc welding method resulted in defects in the first four headers, and although the submerged arc welding process was further refined to have no defects, these four headers still needed to be repaired. To repair these defects, the two companies used a hybrid application of FHPP and rotary friction welding to weld the nozzles to the headers.

100% defect free

“All necessary code compliances were developed, and the welding has proven to be 100% free of defects, and a huge success,” says Schwim. He points out that there are numerous advantages to this new welding method. “There was almost zero distortion in the nozzle orientation; the automated process ensures that all the welds are the same; welding time is 75% less compared to submerged arc welding; and, most importantly, the cost of manufacturing remained the same,” he continues.

WeldCore technology

WeldCore, which formed the basis of this welding technique, is a novel sampling and repair technique that involves removing a cylindrical metallurgical sample from a pipe wall and repairing the site in the steam line using taper friction hydro-pillar processing. This reduces the risk of unexpected catastrophic failure and increases uptime, which leads to substantial cost savings.

The company’s collaboration with eNtsa, which had developed the fundamentals of this process, led to its application and approval. “There are various friction welding technologies in the industry, but for this specific application, they have never been used. It also becomes a difficult and expensive process when developed from scratch,” he explains. “There is a health and safety standard for this welding process, but without a baseline project where this technology was used anywhere in the world, we had to persuade the client and the Association of Inspection Authorities (AIA) to accept it for the project.”

Applications and IP

This welding technique can be applied in the petrochemical, nuclear and power generation industries, where nozzles must be welded to pipes to create a forged-like bond. It now forms part of the intellectual property of Steinmüller Africa and eNtsa. “To date, our two companies are the only ones in the world that have introduced it for this specific application,” says Schwim.

To bring the project to fruition, eNtsa provided the welding technology, the machines, and expertise in the process itself. Steinmüller Africa provided the technical knowledge on welding and required compliance, including the final machining of the stub to header welds. For the duration of this project, eNtsa was appointed as Steinmüller Africa’s sub-contractor under its ISO 3834-2 quality certificate. “We took full responsibility for the welding, and provided the technology to perform the final machining and post-weld heat treatment,” Schwim concludes.

For more information contact Steinmüller Africa, +27 11 806 3321, [email protected], www.steinmuller.bilfinger.com




Share this article:
Share via emailShare via LinkedInPrint this page

Further reading:

The climate change reality in South Africa: An engineer’s call to action
Electrical Power & Protection
This year’s World Engineering Day on 4 March was a powerful reminder of the critical role engineers play in driving progress toward the sustainable development goals.

Read more...
Empowering Africa’s renewable energy future
Electrical Power & Protection
As a global leader in renewable energy technology, SUNGROW has pioneered sustainable power solutions for over 28 years. At the recent Africa Energy Indaba 2025, SUNGROW showcased its advanced energy solutions designed to meet the diverse needs of the African continent.

Read more...
The role of electromechanical solutions in supporting Africa’s industrial growth
Electrical Power & Protection
Africa’s industries are transforming rapidly. Fuelled by a huge demand for energy connectivity, better infrastructure, increased manufacturing and responsible resource management, electromechanical solutions are key to shaping this growth, allowing industries to scale up their operations efficiently and sustainably.

Read more...
Empowering South Africa’s IPPs for a renewable future
Electrical Power & Protection
Many crucial parts of the economy of the future will be hugely energy intensive, foremost amongst which will be electrified transport and the large data processing required by automation and AI. Successful economies will be those that can ensure businesses and investors have access to a stable supply of low-cost renewable energy. South Africa has the opportunity to become a global leader in this regard.

Read more...
Sustainable mining operations escalate as demand for critical materials to double
Electrical Power & Protection
The mining sector is at the forefront of the energy transition due to its role in extracting essential materials and minerals necessary for green technologies. As demand for renewable energy, electric vehicles and other sustainable technologies increases exponentially, so will the demand for these necessary materials.

Read more...
Monitoring partial discharge on medium voltage switchgear
Schneider Electric South Africa Electrical Power & Protection
Schneider Electric South Africa has launched its EcoStruxure Service Plan (ESP) in the Anglophone African region for medium voltage (MV) switchgear

Read more...
Raptor switches
Phoenix Contact Electrical Power & Protection
The Phoenix Contact Raptor switches enable reliable and safe operation in extreme ambient conditions. The managed switch portfolio meets the stringent requirements of IEC 61850-3 and IEEE 1613 standards and is ideal for critical infrastructure and power supply applications.

Read more...
Electrical safety warning indicators
Electrical Power & Protection
Remlive electrical safety warning indicators have been keeping the workplace safe for more than 25 years.

Read more...
Self-contained standalone lightning warning system
Senseca Electrical Power & Protection
The BTD-200 lightning warning system from Biral (UK) is a complete detection and warning system. Its highly specialised aviation grade lightning detection technology delivers the warning as soon as lightning is detected and before the first strike.

Read more...
Half brick second generation converter
Vepac Electronics Electrical Power & Protection
The Supreme series half brick second generation converter from Vepac is composed of isolated, board-mountable, fixed switching frequency DC-DC converters that use synchronous rectification to achieve extremely high power conversion efficiency.

Read more...