Parameter optimization of laser cladding process and resulting microstructure for the repair of tenon on steam turbine blade

Process parameters are crucial to the quality of laser cladding; however, these values are generally determined through trial and error, which brings with it tremendous costs in time and manpower. This study employed the Taguchi Method to determine the optimal parameters for tenon repair on a steam turbine blade using multi-layer laser cladding. In the following experiments, we focused on the quality characteristic of dilution rate (DR). We then performed experiments to verify the effectiveness of the Taguchi results. Analysis of the microstructure and hardness properties of the weldment revealed superior grain refinement in the fusion zone (FZ), compared to the base metal (BM) and specimens that had undergone tempering treatment (TT) at 700 °C for 2 h, resulting in enhanced hardness. Our results demonstrate the effectiveness of the proposed parameter settings in the repair of a damaged tenon, resulting in mechanical properties exceeding those in the BM. Prior to the application of these parameters in the field, mock-up trials were performed to ensure that the repaired tenon met minimum design standards with regard to tensile strength.