Multiphysics Simulation and Experimental Analysis of Laser-Clad Stellite 6 on 316 Stainless Steel Using FEM and RSM

This research explores how process parameters affect the molten pool formation and solidification structure during the laser cladding of Stellite 6 onto a 316 stainless steel substrate. The study combines Finite Element Method (FEM) simulations with empirical-statistical approaches. Using the Response Surface Method (RSM), the Design of Experiments (DOE), optimization, validation, and statistical modeling were carried out. FEM was utilized to simulate and analyze heat distribution generated during the laser cladding process. The FEM model, within an Arbitrary Lagrange-Eulerian (ALE) framework, included material selection, determination of thermal properties, substrate dimensions and meshing, boundary condition application, heat flux input, and temperature-dependent equations for specific heat, thermal conductivity, and density. Thermal analysis and 3D temperature distribution indicated that the molten pool began forming 0.51 seconds after the laser was activated and grew as heat input increased. The peak temperature was reached 0.2 seconds after the laser beam struck the substrate. Simulated and experimental data for single-pass cladding showed acceptable correlation, with 78% and 80.5% prediction accuracy for height and width, respectively. The calculated thermal gradient (G) ranged from 100 to 750 K/mm, and the solidification rate (R) varied from 0.001 to 0.009 m/s. The developed regression models demonstrated strong predictive capabilities, with R² values of 0.90, 0.99, 0.98, and 0.97 for clad height, width, penetration depth, and dilution, respectively. The optimization process yielded a desirability score of 0.795, while experimental validation confirmed the model's reliability, with a maximum prediction error of 13%.