Experimental study on the machining performance of nickel-based superalloy GH4169 milled by AWJ

The experimental study of AWJ milling performance of nickel-based superalloy materials is the basis for the study of milling process parameter optimization. Therefore, this paper focuses on the effect law of process parameters (waterjet pressure, abrasive flow rate, nozzle traverse speed, nozzle tilt angle and step-over distance) on milling performance (milling depth and surface roughness) when milling of nickel-based superalloys via AWJ. The prediction models of milling depth and surface roughness were established using the response surface method. The waterjet pressure is the factor that affects the milling depth and surface roughness the most, while the abrasive flow rate is the factor that affects the milling depth and surface roughness the least. In the interaction term of the milling depth model, the maximum milling depth is obtained at low waterjet pressure when the nozzle tilt angle is between 60 degrees and 80 degrees. While at high waterjet pressure, the maximum milling depth is obtained when the nozzle tilt angle is close to 90 degrees; at any step-over distance, the effect on the milling depth is smaller when the nozzle traverse speed increases above 25 mm/s. In the interaction term of the surface roughness model, when the waterjet pressure is low, there is an optimal nozzle traverse speed to minimize the surface roughness value; at a higher nozzle traverse speed, the minimum surface roughness value occurs at minimum step-over distance. The validation experiment shows that the maximum relative error of the milling depth model is 10.09% and the maximum relative error of the surface roughness model is 12.12%, which proves the validity of the established milling depth model and surface roughness model.