Equipment used in mining, agriculture, and machining frequently fails due to simultaneous wear and corrosion, which shortens service life and increases maintenance costs. To address this, the present work develops high-hardness and corrosion-resistant overlays on S235JR carbon steel using Ni-hard cast iron, aiming to extend component durability in chloride-containing environments and other aggressive service conditions. Ni-hard cast iron powder, conforming to ASTM A532, was deposited on S235JR steel by the Gas Tungsten Arc Welding process at welding currents of 100, 110, and 120 A. The resulting overlays were evaluated for microstructure, hardness, and corrosion behavior. The base steel exhibited a ferritic–pearlitic microstructure with hardness of approximately 129 HV 0.3, whereas the overlays showed a predominantly martensitic matrix with uniformly distributed chromium carbides, achieving surface hardness up to 860 HV 0.3. In a 3.5% sodium chloride solution, the overlays demonstrated significantly lower corrosion rates compared to the base steel (158.23 mils per year), with values of 112 mils per year at 100 A and 27.52 mils per year at 120 A. In conclusion, selecting a higher welding current produced a more uniform martensitic microstructure and enhanced passivating phases, yielding superior hardness and corrosion resistance. These findings show that Ni-hard overlays produced by the Gas Tungsten Arc Welding process offer a practical and economical route to upgrade S235JR steel for harsh industrial environments.
Ostovan et al. (Mon,) studied this question.