A Hardness Study on Laser Cladded Surfaces for a Selected Bead Overlap Conditions

Laser cladding is used to coat a surface of a metal to enhance the metallurgical properties at the surface level of a substrate. For surface cladding operations, overlapping bead geometry is required. Single bead analyses do not provide a complete representation of essential properties; hence, this research focuses on overlapping conditions. The research scope targets the coaxial laser cladding process specifically for P420 stainless steel clad powder using a fiber optic laser with a 4.3 mm spot size on a low/medium carbon structural steel plate (AISI 1018). Many process parameters influence the bead geometrical shape, and it is assumed that the complex temperature distributions within the process could cause subsequent large variations in hardness values. The bead overlap configurations experiments are performed with 40%, 50% and 60% bead overlaps for a three-pass bead formation. A three-dimensional transient fully coupled thermal-metallurgical-mechanical finite element (FE) model was developed to simulate hardness variations in the laser cladded component. For the simulation, the thermo-physical and thermo-mechanical data of the clad and substrate materials in the range of room temperature to the melting temperature are assigned as an input data for the analysis. The numerical results of the microhardness, melt pool, and heat affected zone (HAZ) are compared with the Vickers microhardness measurements, melt pool, and HAZ geometry. The results will provide relevant information for process planning decisions and will provide a baseline for predicting properties of metal additive manufactured components.