Thermal spray coating supplier Thermaspray’s cost considerations restrict the manufacture of critical components from optimal wear and corrosion-resistant materials. Therefore, the bulk of Thermaspray’s work is on new pump parts for original-equipment manufacturers (OEMs), although it also refurbishes parts that have not been too severely damaged.

Protective thermal spray coatings reduce degradation processes on performance- critical pump components, extending the operating life and improving pump efficiencies for optimised uptime and increased production.

The company, headquartered in Olifantsfontein, Gauteng, uses its 20 years’ experience in wear- and corrosion-resistant thermal spray coating to provide a comprehensive range of support coating finishing technologies.

Since pumps are essential in many heavy industries, including mining, they typically operate in extremely stringent and corrosive environments, and are subject to degradation processes such as mechanical wear, corrosion and cavitation. These processes impair the performance critical surfaces in pumps, leading to increased vibrations, a reduction in service life and a continuous decline in throughput and pump efficiency.

Over the last decade, there have been significant technological advancements in the field of thermal spray coating technology, with new coating materials and spray processes significantly outperforming the more traditional coatings.

Thermal spray refers to a coating process where the coating is produced by the projection of a molten stream of particles onto a surface. “Thermal spray is a collection of techniques, which include high-velocity oxygen fuel, plasma, flame spray and arc spray, used to apply materials to substrates,” explains Thermaspray spray shop manager Paul Young. “These techniques can be applied in any industry, such as mining and printing, where there are surfaces suffering from decay.

To prepare a new or worn part for coating, we strip it down to the substrate and we have the necessary experience and capabilities to produce the final product, new or refurbished, to original-equipment (OE) speci- fications,” explains Young.

He notes that worn parts are easily refurbished, stating that, “as these parts are uncoated, [the company] first removes the damage – dents or corroded areas – before applying the thermal spray coatings”.

The removal of the coating material through a grinding process and the reapplication of the coating can extend both the pump’s and the coated part’s service life. By increasing the mean time between failures, the extension of the replacement period will lead to substantial savings on replacement costs and keep downtime to a minimum. “Furthermore, refurbishment of a used pump can deliver savings of between 45% and 65% of the cost of a new pump,” highlights Young.

New uncoated parts such as impellors, rings diffusers, casing rings and shafts are normally received disassembled from the OEMs. Once Thermaspray has applied the relevant coatings, the parts are returned to the OEMs for reassembly.

Young states that the application of protective coatings to OE parts offers end-users substantial cost saving benefits. Coated OE performance-critical parts can be refurbished and reused, whereas uncoated OE parts are normally so badly damaged that refurbishment is impossible. “Coating of OE parts often facilitates assembly as parts are easier to slide on and off.”

He also points out that small faults can occur on parts during the manufacturing process. “Coating these defective parts is a faster and much more affordable process, compared with scrapping and manufacturing a new part.” He notes that Thermaspray can also assist with bringing an undersized part to size.

Young adds that the company applies thermal spray coatings to spare parts as well, ensuring that they are protected before they are used for replacement.

Thermaspray, through a joint venture with Cape Town-based innovative vacuum coatings, rapid and complex surface analysis company Surcotec offers an extensive portfolio of engineering and thermal spray coating solutions that extend component life cycles to assist OEMs and end-users across Southern Africa in reducing costs and increasing production.

The companies’ high-quality wear- and corrosion-resistant thermal spray coatings, plasma transferred arc cladding and polymer coatings are augmented by a host of specialised allied services.