The implementation of the thermal spray process as a replacement for hard-chrome plating in hydraulic cylinders is impeded by inadequately stringent health and safety regulations in South Africa, says maintenance and fabrication specialist Weartech technical director Adam Wintle.
“The . . . process has been used for years in the US and Europe as a health precaution. As a result, various industries that use the . . . process in the US and Europe have benefited from the extended life of hydraulic rods . . . also culminating in chrome plating being banned in specific parts,” he points out.
A hydraulic cylinder is a mechanical actuator that generates force through a stroke. It consists of a cylinder barrel, in which a piston connected to a piston rod moves back and forth.
A piston rod requires smooth or hard surfaces on the outer diameter for proper sealing. The production of hard chrome is required for chrome-plating the piston rods in hydraulic cylinders, which produces hexavalent chromium – a verified carcinogen.
Wintle explains that using the thermal spray process for hydraulic cylinders has significant health benefits, since the process produces fewer carcinogens than chrome plating.
Thermal spray offers several alternative super alloy-, ceramic- or carbide-based coatings as replacement for hard-chrome plating. These coatings are applied using high-velocity oxygen fuel or plasma spray equipment.
Weartech notes that thermal-sprayed surfaces resist aggressive environmental conditions, such as corrosion, and outperform the hard chrome plated coatings.
Wintle clarifies that the process is uncomplicated and requires only initial training and installation.
He adds that thermal-sprayed surfaces are extremely hard and sometimes require finishing using diamond-finishing products.