Abstract
Laser cladding is a widely used surface modification technique in various industrial sectors such as offshore, power generation, and oil and gas. The high energy density and coherence of the laser beam enable rapid heating and cooling of the molten pool. As a result of this rapid solidification process, solute retention differs significantly from equilibrium solidification, minimizing or eliminating segregation and thereby enhancing the alloy’s solid-solution limit. Among the key benefits of laser cladding, its ability to produce a fine-grained structure with minimal heat-affected zone, low distortion, and low dilution rate can be pointed out.
Among various application areas, laser cladding is used for corrosion protection in harsh environments by depositing a corrosion-resistant alloy such as IN625 onto cost-effective structural base alloys. In this research, an ytterbium fiber laser (16 kW) was utilized to optimize the laser cladding process for deposition of IN625 alloy on HSLA steel substrate. The optimization was conducted by single bead depositions with varying key parameters, including laser power, scanning speed, wire feed rate, and defocusing distance. The deposited samples were then sectioned for morphological, microstructural and mechanical investigation. The results revealed that under optimal deposition conditions, an iron dilution rate of less than 5% is achievable, which is in line with the recommended values in the literature. The resulting microstructure exhibited both columnar and equiaxed morphology, with the gamma phase being the predominant feature. Dependency of this microstructural features and corresponding microhardness values were then further analyzed across the selected cases with optimum dilution rate and wetting angle to identify the cases with suitable deposition and potentially beneficial microstructure for corrosion protection. The outcomes of the current research will facilitate process optimization for continuous cladding of IN625 of larger substrates made of HSLA steel alloy.