valves and non-return valves in sizes from 200 mm and up,” explains Tudhope. “This enables these high value steam valves to be repaired in a fraction of the time that it would take to cut that valve out of the pipework and repair it off-site. This offers huge economic advantages to power station operators,” he adds. With respect to the repair of the seats for these valves, he says these are typically clad with exotic materials such as Stellite. “These materials are often difficult to weld and machine, so we refurbish the seats in our 3 500 m 2 factory in Spartan, Kempton Park. “Since we are working extensively with SOEs, 2Roads’ Level 1 B-BBEE status is in- valuable to us in terms of ongoing access to this work. We also see this merger as an opportunity to expand our offering to dif- ferent SOEs based on the expertise we have been developed over the years,” Tudhope informs African Fusion. The AWT factory, he says, offers a wide range of both welding and machining capabilities. “We prefer to combine these two offerings by doing work that involves weld repair followed by precise machining back to OEM specifications. We are special- ists at restoring the critical components of machines back to their as-new condition,” he notes. “At the moment, for example, we do new manufacture on boiler feed pumps for major power stations, which involves very thick section welding of up to 70 mm tube thicknesses of multistage barrels. The welding has to test 100% flaw-free using phased-array UT and we do the work using a combination of mechanised MIG welding and manual metal arc welding (MMAW). In terms of materials, some barrels are clad internally with a layer of 316L stain- less steel using a rotator and a column and boom system. “AWT has long been a spe- cialist welder of a variety of high alloy and exotic materials. In one particular pump barrel, some nozzles are WB36, a Ni-Cu-Mo steel micro-alloyed with niobium, others are cast 316L and yet more components are made from 10CrMo910. Coupled with the internal cladding and final PWHT, this has been a real welding engineers’ challenge!” he exclaims Many high temperature valve parts require the use of the creep resistant 2¼Cr1Mo and CrMoV steels, while yet other valve parts use materials that are barely weldable, such as spindles made from X19CrMoVNb11-1, a high chromium martensitic boiler steel that is very sensitive to welding,” Tudhope reveals. “Weld repair
Above: A main steam stop valve repaired by AWT at is Kempton Park facility. Right: A repaired pulper rotor being machined back to its as-new condition. also offer the chance to improve the surface properties of the base material.” Kagisho Bapela elaborates: “It is often quicker and much more cost effective to use a locally engineered procedure to repair process plant equipment than to procure and install new replacement components. Procurement processes can be long, both in terms of getting the capital expense authorised and then waiting for the delivery from an OEM – and if downtime is involved, this can be very costly. Repair services can usually be justified from opera- tional budgets, so spending authorisation delays are also shorter,” he points out. “Going forward, we are looking to cre- ate capacity in an allied suite of services to keep process plants running with fewer interruptions, being on constant standby
to help customers keep their infrastruc- ture healthy. SOEs are all facing having to rebuild their infrastructure: from power to transport to water, everyone seems to be short of the engineering capacity needed to restore service delivery levels. He reveals that the 2Roads Group will also be establishing a fully-fledged train- ing centre that will offer management, vocational and skills development training. “This will include training and skills transfer programmes based on access to practical training on welding techniques used by AWT,” says Bapela. “Through this partnership with 2Roads, we see huge opportunities to access mar- kets where we have not previously been active,” Tudhope concludes. www.2roads.co.za: www.appliedwelding.co.za
The refurbishment of a water pump impeller at AWT.
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March 2022
AFRICAN FUSION
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