Estimation of Bead Size and Catchment Efficiency in Laser Cladding

Prediction of the geometry and dimensions of the clad bead in a laser cladding procedure is important to ensure dimensional accuracy and efficient functionality. Practical expressions for the prediction of these dimensions can reduce the burden of expertise and save time involved with the usage of numerical models among practitioners. This presentation discusses mathematical expressions developed through analytical modeling based on Rosenthal’s solutions for estimating the width, height, and catchment efficiency of clad beads from information on known process parameters. Effective thermo-physical properties of the substrate are determined to consider their variation with temperature which is often overlooked. An expression for the thermal efficiency of the cladding process taking into account the shadowing effect of the powder cloud is proposed. An improved analytical estimation of catchment efficiency based on proper integration of mass flow over the surface of the weld pool is introduced, assuming a gaussian distribution for the laser power and the powder flow with the same distribution parameters. The model developed predicts width and catchment efficiency within 10% accuracy, with the only exceptions being the highest velocity and the lowest laser power tested. The predictions of bead height show a systematic error of 18% on average.