In the light of global economic pressures and the consequent difficult trading environment, Afrox continues to invest in the development of people, products and processes. African Fusion talks to Johan Pieterse and Hennie van Rhyn about some of the initiatives the company has put in place to ensure the sustainability of the welding industry in South Africa.
Pieterse, Afrox’ business manager for manufacturing industries, believes that current trading conditions are tough. “The economy is pretty flat and certainly not growing much. If anything, we are looking at a net decline. Some shielding is coming from the ongoing build projects, but not enough to contribute to growth,” he says.
In response, he believes that it is vital to stay focused and to continue to develop local capacity. “We believe that we need to double our efforts to upskill local people, introduce new processes, improve the quality of our local welding consumables and to support best-practice welding and safety standards so as to emerge as a competitive nation. Productivity, quality and cost effectiveness all need to be improved for South African manufacturing and fabrication to survive these difficult times,” he suggests.
The power generation projects have already presented several challenges. “We have all gone up a steep learning curve, but the first of the Medupi boilers is now nearing completion and we are now in a much better position to support and supply the remainder of the Eskom projects. The experience we have picked up at Medupi is already helping us with Kusile,” he adds.
One of the key challenges was to conform to internationally required standards for locally manufactured consumables. “We have long had AWS and ASME standards but we have also had to add European standards to make sure that all of our locally manufactured products conform to the standards required by the European approval bodies,” he explains. “We also installed a vacuum packing line to enable us to keep supplying our local power stations with ‘proudly-South African’ products,” he tells African Fusion.
“More importantly, though, we found that we needed to provide support to ensure that the quality of the finished welds would conform to the strict quality requirements of the main contractors. We therefore had to assist with welder training, welding procedure specifications (WPSs) and procedure qualification records (PQRs) to make sure that all the locally produced consumables were being effectively applied,” he adds.
“The lack of welding skills became apparent very early on and so we have been actively involved in welding skills development for several years now. Our focus is on getting welders up and running on the particular process that they need to apply, GMAW or FCAW, for example. We train welders so as to optimise their productivity and to enable the best possible outcome in terms of both cost and quality.
“Welding costs do not come down simply by purchasing cheaper products,” warns Pieterse. “Competitiveness is all about throughput – saving on labour and overhead costs. A knowledgeable guy with well set up equipment and using a WPS developed for optimal performance and quality will almost always produce the best consistency and the lowest overall cost,” he says. “It is never a good idea to associate the process costs with lower equipment and consumable costs, because consistent welding speeds and quality cannot be achieved with inferior products.”
Another key service now being offered by Afrox is towards the enhancement of South Africa’s on-site safety standards. “Our Safety Solutions Programme aims to make sure that everyone on a site is aware of the dangers and knows how to deal with oxy-fuel gases and processes,” explains van Rhyn.
The starting point for the programme is operator training to ensure that gas-related cutting and heating processes can be performed safely at a customer’s premises. “We also do risk-assessments and risk mitigation to assist customers to upgrade the safety of their facilities,” adds van Rhyn. “We aim to ensure that our key customers are able to use gas equipment safely, that the equipment conforms to all national standards and that all operators are trained and accredited in the safe handling and use of oxy-fuel gas supply systems.”
And while talking about gas equipment, Pieterse points out that Afrox, via its parent, the Linde Group, has recently launched Lindoflamm®, an acetylene-based flame solution that can improve efficiency, quality and productivity. “Lindoflamm reduces the costs of hot forming, flame straightening and pre- and post-heat treatment operations,” says Pieterse. “The energy from Acetylene, the primary heat source for Lindoflamm, transfers heat much more effectively into the workpiece, so the energy goes into the steel where it is needed, instead of into the air,” he says. “A fully mechanised system can improve productivity and reduce s costs by as much as 30%,” he suggests.
The process is widely used overseas as the state-of-the-art heating solution and is catching on in South Africa in companies seeking to raise standards and improve productivity. “It is ideal for fabricating boilers and for the flame straightening applications,” Pieterse adds.
Shifting attention to gases, van Rhyn says that Afrox is fast expanding the laser gas market. The R100-million re-engineering of Afrox’ Gases Operations Centre (GOC) in Germiston has made it possible to quickly and effectively make complex gas mixtures to very high purities. “We can now supply a wide range of special laser gas mixes. No laser can operate without these. Different lasers use different mixes that optimise the laser resonator performance, and each OEM requires a different composition,” he explains. “As part of the global Linde Group, we work with all the global OEMs, like Trumpf, Rofin, Amada, Mazak and Bystronic, and we are able to support all of these lasers with gas according to their specifications. Because of our world-class GOC in Germiston, we can mix gases to the exact composition very competitively– and it’s easy to order and mix because each prescription is recorded and stored in the system as a material number.
Historically, lasers like the Trumpf machines have used pure gases in separate cylinders, argon, nitrogen and CO2, and incorporated a gas mixing system to achieve the resonant gas required. “On these lasers, we simply feed the different gases into the laser at the pressures required and the machine mixes to the composition required. But the gases used have to be very pure. Argon and nitrogen need to be N5 gases, which means 99,999% pure and CO2 is an N4,5 gas, 99,995% pure,” explains Rhyn.
“It is more efficient and cost effective for the customer, however, to use a single premixed gas and Linde is negotiating with laser OEMs to manufacture current generation machines to use premixed gases,” he adds.
The South African laser market is expanding fast. “We are experiencing growth of 67% year-on-year and we now know of 450-460 active laser-cutting machines operating in South Africa, excluding all of the second-hand imports.
As well as the resonator gas requirements, lasers also require a purge gas, which is often high-purity compressed air or nitrogen, and a cutting assist gas. “Laser assist gases are the equivalent of the cutting gas for flame processes. Generally, for mild and carbon steel cutting, oxygen is used as the assist gas. "Oxygen is reactive, so it creates additional heat as it burns through the cut,” Pieterse explains. “But for stainless steel and aluminium, nitrogen is used, which is more inert. The laser, therefore, does all the melting and you need high pressure to blow through the cut,” he adds.
A high-flow high-pressure system called Trifecta is used for lasers using high-pressure nitrogen. “This is a system that takes low pressure liquid nitrogen at about -180˚C, passes it through a vaporiser and then through two buffer tanks, which raise the temperature and pressure to about 33 bar at 20˚C. As the gas heats up, it expands and the pressure increases,” says van Rhyn.
Through these and many other initiatives, Afrox is gearing up to support and sustain South Africa as a competitive manufacturing destination: “We are able to supply local industry with leading products and technologies and support these with an experienced and a knowledgeable team. Technology transfer is what we really do,” Pieterse concludes.