Long-life-liner manufacturer Rio-Carb received a large order in June for 190-mm- to 2-m-diameter chromium-carbide-CrC-lined dust extraction ducting for a BHP Billiton plant from air pollution control specialist Genair Pollution Projects, the main design and installation contractor of the project.

“Dust extractor pipes are difficult to replace when they wear out because of their size; therefore, when a pipe is assembled, precision and high quality are important. Using a combination of 5 mm and 8 mm Rio-Carb mild steel CrC overlay plate for the bends of these dust extraction plants will enable the ducting to handle high abrasion conditions,” explains Genair MD Wynand Schoeman.

He adds that, where the pipe bends, dust impinges on the side of the plates, which causes wear. To solve this problem, Rio-Carb applies a double layer weld onto the mild steel CrC lining, which provides proper structural strength, while the carbon element ensures the hardness of the pipes.

“CrC liners contain 24% to 25% chromium, which is 12 to 15 times higher than in 400 and 500 Q+T martensitic steels. “CrC has a heat resistance of up to 500 °C and when deposited by weld cladding, it obtains a hardness level of between 56 Rc to 58 Rc. “Our exclusive MaxC5 process ensures that the CrC crystals form vertical dend- rites, or columns, when solidifying – like bristles on a toothbrush. This is ideal for long life under sliding abrasion conditions,” explains Rio-Carb director Colin Maine.

The company says the quality and long-term benefits guaranteed by its CrC lining have encouraged it to expand its footprint in Africa, where mineral processing plants augment its long-life CrC liners.

Maine adds that the company is also doing a lot of work in steel fabrication, as it aims to provide a one-stop service for its clients to provide them with a full package of services for their projects.

“We have cladding, plasma cutting, rolling, pressing, stud welding and trained computer-aided-design (CAD) designers all under one roof. This closed-loop service enables us to offer quick deliveries with certified packages, such as welding and studding, to AWS specifications. Large stocks of CrC overlay plates are always available at the factory.

“This stock amounts to about two- and-a-half month’s turnover supply and large jobs can, therefore, be started in a matter of days, if not hours. The full data-profile rolling of each liner is kept on a ten-year CAD database for rapid delivery,” highlights Maine.

Despite the labour and economic unrest in South Africa’s mining sector, he does not believe Rio-Carb will be affected in any way, as the company still strives to meet the market’s needs and supply the relevant services.