Spheroidal graphite cast iron is a material widely used in the industry for the manufacturing of all kind of covers and protective casings thanks to its good combination of mechanical properties, processability and cost. When cast iron components are put into service in corrosive environments the most common approach to protect the components is painting them. The protective painting has been found to flake off with time when aggressive washing procedures, such as the ones used in the Food & Beverage industry, are applied several times.

In this project, the coating of cast iron with a corrosion resistant AISI 316L stainless steel by Laser Metal Powder Deposition has been studied as an alternative protection against corrosion. Several samples with different combinations of substrate preparation, number of layers and surface conditions were produced and analysed by optical microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, wash down tests and salt spray chamber corrosion tests.

Main results show that the diffusion of carbon from the carbon-rich cast iron to the stainless steel coating, which would have a negative effect on the corrosion resistant properties, was significantly low as a result of the low penetration and dilution achieved during the laser metal powder deposition process. The deposited stainless steel coatings successfully protected the substrate during the corrosion tests and the integrity of the coatings is not expected to fail during the washing producers applied in the industry.